Title of Invention	"VEHICLE MOTOR CONTROL DEVICE"
Abstract	As the motors that drive the wheels of a vehicle, there are provided three motors for each chassis. When controlling the respective motors individually by inverters, there are provided: acceleration detection and control sections (26) that throttle the torque on detection of increase of the rate of change with time of the speed signal of a motor by more than a prescribed value, and slippage speed detection and control sections (27) that throttle the torque in accordance with the amount by which a motor speed signal has increased from a prescribed reference speed. The changeover control section (28) effects changeover such that control of the inverter (11) that controls the motor that is positioned rearmost in the direction of travel of the vehicle in each chassis is normally performed by the acceleration detection and control section (26) and control of the inverters that control the other two motors is performed by the slippage speed detection and control section (27).

Title of Invention

"VEHICLE MOTOR CONTROL DEVICE"

Abstract

As the motors that drive the wheels of a vehicle, there are provided three motors for each chassis. When controlling the respective motors individually by inverters, there are provided: acceleration detection and control sections (26) that throttle the torque on detection of increase of the rate of change with time of the speed signal of a motor by more than a prescribed value, and slippage speed detection and control sections (27) that throttle the torque in accordance with the amount by which a motor speed signal has increased from a prescribed reference speed. The changeover control section (28) effects changeover such that control of the inverter (11) that controls the motor that is positioned rearmost in the direction of travel of the vehicle in each chassis is normally performed by the acceleration detection and control section (26) and control of the inverters that control the other two motors is performed by the slippage speed detection and control section (27).

Full Text	TITLE OP THE INVENTION VEHICLE MOTOR CONTROL DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle motor control device for controlling drive of a rail vehicle. 2. Description of the Related Art A vehicle motor control device that controls drive of a rail vehicle performs anti-skid readhesion (or re-adhesion) control in order to prevent skidding of the vehicle wheels. Such anti-skid readhesion control may be performed by the method of acceleration detection, in which anti-skid readhesion control is performed by detecting skidding by calculating the speed change rate of the vehicle shaft or motor shaft or by the method of slippage speed detection, in which skidding is detected by calculating the skidding speed (or slipping speed). FIG. 1 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional acceleration detection method. FIG. 1 shows the case in which there are six wheel-driving motor shafts in a single vehicle, these being independently controlled by respective inverters. The rotational speed of the motors 12a to 12f that are driven by the inverters 11a to llf is detected by rotational speed detectors (such as for example pulse generators or resolvers) 13a to 13f and input to anti-skid readhesion control sections 14a to 14f. The anti-skid readhesion control sections 14a to 14f have the same construction, so only the anti-skid readhesion section 14a will be described below. The rotational speed (rotational number) of the motor 12a that is detected by the rotation speed detector (pulse generator) 13a is converted into a speed signal that is input to the speed calculation section 15a of the anti-skid readhesion control section 14a. The rate of change of the speed signal is found by inputting the speed signal found by the speed calculation section 15a to the acceleration detection section 16a. The acceleration detection section 16a then determines whether the rate of change of the speed signal is at or above a prescribed value: if the rate of change of the speed signal is at or above the prescribed value, the acceleration detection section 16a identifies (detects) the skidding condition; if the rate of change of the speed signal is less than the prescribed value, the acceleration detection section 16a identifies recovery. The torque throttling/recovery calculation section 17a calculates and outputs the amount of torque throttling or recovery in accordance with the skidding identification signal of the acceleration detection section 16a. The torque instruction pattern output section 18a outputs a torque instruction pattern: the output of the torque throttling/recovery calculation section 17a is output as the final torque instruction after being subtracted from the torque instruction pattern from the torque instruction pattern output section 18a by a subtracter 19a. Next, FIG. 2 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional slippage speed detection method. FIG. 2 shows the case in which there are six wheel-driving motor shafts in a single vehicle, these being independently controlled by respective inverters. The rotational speed of the motors 12a to 12f that are driven by the inverters lla to llf is detected by rotational speed detectors 13a to 13f and input to speed calculation sections 15a to 15f of anti-skid readhesion control sections 14a to 14f, where it is converted to a speed signal. The speed signals that are calculated by the speed calculation sections 15a to 15f are input to a reference speed calculation section 20, where a reference speed is calculated. The calculation of the reference speed may be performed by for example a method as illustrated in the Journal of the Electrical Association of Japan Industrial Applications Section Vol. 121-D' No. 9. 2001 p 928 (Figure 11) The reference speed calculated by the reference speed calculation section 20 is input to the subtracters 21a to 21f of the respective anti-skid readhesion control sections 14a to 14f, where the reference speed is subtracted from the speed signals of each motor shaft found by the speed calculation sections 15a to 15f, and the amount of deviation greater than zero is input to the preliminary delay amplification sections 22a to 22f. The outputs of the preliminary delay amplification sections 22a to 22f are subtracted from the torque instruction patterns from the torque instruction pattern output sections 18a to 18f and the results output as the final torque instruction. Some references, such as for example Published Japanese Patent No. 3152785 (Laid-open Japanese Patent Application No, H. 6-261415) disclose arrangements wherein, when controlling individual controllers that separately control each motor of the vehicle motors, high precision control can be performed without affecting other motors even if skidding occurs in any one motor. However, with a vehicle motor control device in which anti-skid readhesion control is performed by the conventional acceleration detection method, torque throttling in order to achieve readhesion is performed immediately in a positive fashion on detection of skidding, so torque throttling tends to be abrupt and the amount of throttling tends to be large. Consequently, in cases where skidding occurs frequently, the average acceleration torque is greatly lowered, or the abrupt throttling of the torque that is performed for each shaft as mentioned in the Patent Publication referred to above may give rise to shifting of the shaft load, tending to cause skidding of other shafts. On the other hand, in the case of a vehicle motor control device in which anti-skid readhesion control is performed by the conventional slippage speed detection method, the amount of torque throttling is determined in accordance with the amount of the slippage speed produced by the skidding, so, although the amount of torque throttling can be made smaller than in the case of the acceleration detection method, the torque throttling response is lowered due to the first-order lag element (or preliminary delay element). Consequently, a mode is generated in which readhesion is not reliably achieved, so there is a risk of destabilization of the reference speed if skidding continues in respect of all six shafts. SUMMARY OF THE INVENTION Accordingly, an advantage of an aspect of the present invention is to provide a novel vehicle motor control device whereby the amount of torque throttling on skidding is reduced and stable acceleration performance is obtained without destabilization of the reference speed. The above object can be achieved by a rotary electrical machine constructed as follows. Specifically, a vehicle motor control device having as motors driving the wheels of a vehicle three motors per chassis and further having inverters that individually control respective motors comprises: an acceleration detection and control section provided for each respective inverter and that throttles the torque on detecting increase of the rate of change with time of the speed signal of the aforementioned motors above a prescribed value; a slippage speed detection and control section provided for each respective inverter and that throttles the torque in response to the amount of increase of the speed signal of said motor from a prescribed reference speed; and a changeover control section that changes over the inverter that controls the motor that is located rearmost in the direction of vehicle travel in each chassis so as to be controlled by said acceleration detection and control section and the inverters that control the other two motors so as to be controlled by said slippage speed detection and control section. According to the present invention, even under conditions of poor adhesion between the rail and vehicle wheels such that skidding occurs frequently, lowering of the acceleration performance can be suppressed, since the minimum torque throttling amount in accordance with the amount of skidding speed suffices, and a stable reference speed is obtained. BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: FIG. 1 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional acceleration detection method. FIG. 2 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional slippage speed detection method. FIG. 3 is a block diagram of the case where a vehicle motor control device according to a first embodiment of the present invention is applied to a vehicle. FIG. 4 is a detailed block diagram of a vehicle motor control device according to a first embodiment of the present invention. FIG. 5 is an operating waveform diagram showing the operation in the case of an acceleration detection and control method with an acceleration detection and control section according to a first embodiment of the present invention. FIG. 6 is an operating waveform diagram of a slippage speed detection and control method with a slippage speed detection and control section according to a first embodiment of the present invention. FIG. 7 is a detailed block layout diagram of a vehicle motor control device according to a second embodiment of the present invention. FIG. 8 is a block layout diagram of a reference speed abnormality detection section according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 3 thereof, two embodiments of the present invention will be described. (First embodiment) FIG. 3 is a block diagram of the case where a vehicle motor control device according to a first embodiment of the present invention is applied to a vehicle. In the lower part of the vehicle body 23 of the vehicle, there are provided two chassis frames 24A, 24B; vehicle shafts 25a, 25b, 25c are mounted on the chassis frame 24a and vehicle shafts 25d, 25e, 25f are mounted on the chassis frame 24B. These vehicle shafts are respectively driven by motors 12a to 12f. Hereinbelow, the motor shafts respectively corresponding to the six vehicle shafts 25a to 25f will be described as the No. 1 shaft, No. 2 shaft, No. 3 shaft, No. 4 shaft, No. 5 shaft and No. 6 shaft, from the direction of travel in the case of an instruction for forward travel. The rotational speeds of the motors 12a to 12f corresponding to the respective shafts are respectively detected by the rotational speed detectors 13a to 13f and input to the anti-skid readhesion control sections 14a to 14f. The anti-skid readhesion control sections 14a to 14f include acceleration detection and control sections 26a to 26f, slippage speed detection and control sections 27a to 27f and changeover control sections 28a to 28f. The acceleration detection and control sections 26a to 26f perform anti-skid readhesion control by throttling the torque on detection of skidding; this detection is performed by sensing increase of the rate of change with time of the speed signal of the motors 12a to 12f above a prescribed value. In contrast, the slippage speed detection and control sections 27a to 27f perform anti-skid readhesion control by throttling the torque in response to the amount of increase of the speed signals Va to Vf from the motors 12a to 12f from a prescribed reference speed Vref. The prescribed reference speed Vref is found by calculation performed by the reference speed calculation section 20. In this embodiment of the invention, the minimum value of the speed signals Va to Vf of the motors 12a to 12f is selected as the reference speed. Next, the changeover control sections 28a to 28f effect changeover between the acceleration detection and control sections 26a to 26f and the slippage speed detection and control sections 27a to 27f; normally, by using the acceleration detection and control sections 26a to 26f, they control the inverter that controls the motor that is positioned rearmost in the direction of travel of the vehicle for each chassis and effect changeover such that the inverters that control the other two motors are controlled by the slippage speed detection and control sections 27a to 27f. For example, if the direction of travel of the vehicle is the leftwards direction in FIG. 1, it is arranged that the motor 12c (12f) that is positioned rearmost in the direction of travel of the vehicle on a chassis is controlled by the acceleration detection and control sections 26a to 26f, while the other two motors 12a, 12b (12d, 12e) are controlled by the slippage speed detection and control sections 27a to 27f. FIG. 4 is a detailed block layout diagram of a vehicle motor control device according to a first embodiment of the present invention. The acceleration detection and control sections 26a to 26f and the slippage speed detection and control sections 27a to 27f of the anti-skid readhesion control sections 14a to 14f are of the same construction, so only the acceleration detection and control section 26a and the slippage speed detection and control section 27a of the anti-skid readhesion control section 14a will be described. The acceleration detection and control section 26a includes a speed calculation section 15a, an acceleration detection section 16a, a torque throttling/recovery calculation section 17a, a switch 29a, a subtracter 19a, and a torque instruction pattern output section 18a. Also, the slippage speed detection and control section 27a includes a speed calculation section 15a, subtracter 30a, preliminary delay amplifier 22a, switch 29a, subtracter 19a, and torque instruction pattern output section 18a. Changeover of the acceleration detection and control section 26a and slippage speed detection and control section 27a is performed by changeover of the switch 29a. This changeover is performed by the changeover control section 28a. First of all, the operation when the acceleration detection and control section 26a is selected by the switch 29a will be described. The speed signal Va converted by the speed calculation section 15a is input to the acceleration detection section 16a, and the change rate of the speed signal Va is thereby found. If the rate of change of this speed signal Va exceeds the prescribed value, skidding is identified, and if the prescribed value is not exceeded, recovery is identified. The torque throttling/recovery calculation section 17a calculates and outputs a torque throttling amount or recovery amount in accordance with the skidding identification signal obtained in the acceleration detection section 16a to the subtracter 19a through the switch 29a. The subtracter 19a compares this with the torque instruction pattern from the torque instruction pattern output section 18a, and outputs a torque instruction corresponding to the difference thereof. FIG. 5 is an operating waveform diagram showing the operation of the acceleration detection and control method in the acceleration detection and control section 26a. When adhesion between the vehicle wheels and the rail drops due for example to rain, causing the vehicle wheels to skid, there is an abrupt increase in the speed change rate, so, at the time-point tl where the speed change rate exceeds a certain set value A, a skidding detection flag is set, causing torque throttling to be commenced with a comparatively steep gradient. Then, at the time-point t2 where the speed change rate has become less than a given set value B, the skid detection flag is removed, allowing operation to be performed in which restoration is slowly effected to the original torque instruction, with a preliminary delay constant provided by a time constant i. Substantially reliable readhesion can therefore be performed with a motor shaft controlled in this way. Next, the operation in the case where the slippage speed detection and control section 21 a is selected by the switch 29a will be described. The speed signal Va converted by the speed calculation section 15a is input to the subtracter 30a, The subtracter 30a inputs a reference speed Vref from the reference speed calculation section 20, finds the deviation of the speed signal Va and the reference speed Vref, and outputs this deviation to the preliminary delay amplification section 22a. The reference speed calculation section 20 selects the minimum value of the speed signals Va to Vf calculated by the speed calculation sections 15a to 15f of the No. 1 shaft to No. 6 shaft, and outputs this as the reference speed Vref. The preliminary delay amplification section 22a finds the torque throttling amount from the deviation greater than zero of the speed signal Va and reference speed Vref and outputs the result to the subtracter 19a through the switch 29a. The subtracter compares this with the torque instruction pattern from the torque instruction pattern output section 18a, and outputs a torque instruction in accordance with the difference thereof. FIG. 6 is an operational waveform diagram showing operation in accordance with the slippage speed detection and control method in the slippage speed detection and control section 27a. When at the time-point t1 the speed signal Va of the motor 12a increases by more than a certain value from the reference speed Vref as a result of skidding of the vehicle wheels, the speed signal Va is subtracted from the torque instruction pattern in accordance with the amount of this increase. The torque throttling amount becomes zero at the time point t2 where the deviation of the speed signal Va and the reference speed Vref of the motor 12a has become less than a certain value due to readhesion as a result of such torque throttling. Under such speed detection control, the torque is continuously controlled by the deviation amount while allowing slippage of the vehicle wheels, so, under conditions in which the rail adhesion has decreased, the speed signal Va of the motor 12a is normally larger than the reference speed Vref. Next, changeover of the acceleration detection and control sections 26a to 26f and the slippage speed detection and control sections 27a to 21 £ will be described. Changeover of the acceleration detection and control sections 26a to 26f and the slippage speed detection and control sections 27a to 27f is performed by the changeover control sections 28a to 28f. The changeover control section 28a of the anti-skid readhesion control section 14a associated with the No. 1 shaft performs changeover under the same condition as the changeover control section 28d of the anti-skid readhesion control section 14d associated with the No. 4 shaft. Likewise, the changeover section 28b of the anti-skid readhesion control section 14b associated with the No. 2 shaft and the changeover control section 28e of the antiskid readhesion control section 14e associated with the No. 5 shaft perform changeover under the same condition and the changeover section 28c of the anti-skid readhesion control section 14c associated with the No. 3 shaft and the changeover control section 28f of the anti-skid readhesion control section 14f associated with the No. 6 shaft perform changeover under the same condition. Regarding the No. 1 shaft and No. 4 shaft, the changeover control sections 28a, 28d arrive at their decisions on input of the forward travel instruction and shaft number to the AND circuits 31a, 31d. In the event of a forward drive instruction, the AND circuits 31a, 31d of the changeover control sections 28a, 28d assume logic value "1" and the switches 29a, 29d are changed over to the side of the slippage speed detection and control section 27a. Contrariwise, in the event of a backward travel instruction, the AND circuits 31a, 31d of the changeover control sections 28a, 28d become logic value "0" and the switches 29a, 29d are changed over to the side of the acceleration detection and control section 26a. Regarding the No. 2 and No. 5 shaft, the changeover control sections 28b, 28e arrive at their decisions by input of a forward travel or backward travel instruction by the OR circuits 32b, 32e and by input of the outputs of the OR circuits 32b, 32e and the shaft numbers to the AND circuits 31b, 31e. Consequently, both in the event of a forward travel instruction and in the event of a backward travel instruction, the logic value becomes "1" and the switches 29a, 29d are changed over to the side of the slippage speed detection and control section 27a. Regarding the No. 3 shaft and No. 6 shaft, the changeover control sections 28c, 28f arrive at their decisions by input of the backward travel instruction and shaft number to the AND circuits 31c, 31f. In the event of a backward travel instruction, the AND circuits 31c, 31f of the changeover control sections 28c, 28f become logic value "1" and the switches 29c, 29f are changed over to the side of the slippage speed detection and control section 27a. Contrariwise, in the event of a forward travel instruction, the AND circuits 31c, 31f of the changeover control sections 28c, 28f become logic value "0", and the switches 29c, 29f are changed over to the side of the acceleration detection and control section 26a. In this way, the first and second motors 12a, 12b and the fourth and fifth motors 12d, 12e with respect to the direction of forward travel are controlled by the slippage speed detection and control section 27, while the third and sixth motors 12c, 12f are controlled by the acceleration detection and control section 26. The reason for this is in order to obtain a stable reference speed, in view of the fact that, considering shifting of the shaft load of the vehicle, the magnitude of the shaft load is a minimum in the case of the first motor shaft and thereafter increases in the order: second, fourth, third, fifth and sixth shafts. In other words, reliable readhesion can be achieved by employing acceleration detection and control as the control method for the third and sixth motors, which are the tail motors, where the shaft load is largest in each chassis. By employing slippage speed detection and control for the other shafts, overall torque throttling is minimized. With the first embodiment, by using the acceleration detection and control section 26 to control the third and sixth motors, which are the tail motors, where the shaft load is largest in each chassis, and using the slippage speed detection and control section 27 to control the other shafts, reliable readhesion of the vehicle wheels with the rails can be achieved, and shifting of the shaft load can be prevented from provoking skidding of the other shafts, thereby making it possible to minimize the amount of overall torque throttling. (Second embodiment) FIG. 7 is a detailed block layout diagram of a vehicle motor control device according to a second embodiment of the present invention. In this second embodiment, in contrast to the first embodiment shown in FIG. 4, reference speed abnormality detection sections 33a to 33f are provided in the changeover control sections 28a to 28f. Elements which are the same as in the case of FIG. 4 are given the same reference symbols and repeated description is dispensed with. The changeover control sections 28a, 28d of the No. I shaft and No. 4 shaft include AND circuits 31a, 31d that input a forward travel instruction and shaft number, and AND circuits 34a, 34d that input the output of the AND circuits 31a, 31d and the output of reference speed abnormality detection sections 33a, 33d. When the reference speed Vref of the reference speed abnormality detection sections 33a, 33d is abnormal, a logic value "0" is output. Consequently, when the reference speed Vref is abnormal, the outputs of the AND circuits 34a, 34d become logic value "0" irrespective of the output of the AND circuits 31a, 31d, so the acceleration detection and control section 26 is selected. The changeover control sections 28b, 28e of the No. 2 shaft and No. 5 shaft include OR circuits 32b, 32e that input a forward travel instruction and backward travel instruction, AND circuits 31b, 31e that input the outputs of the OR circuits 32b, 32e and the shaft number, and AND circuits 34b, 34e that input the output of the AND circuits 31b, 31e and the output of the reference speed abnormality detection sections 33b, 33e. The reference speed abnormality detection sections 33b, 33e output logic value "0" when the reference speed Vref is abnormal. Consequently, the output of the AND circuits 34b, 34e becomes logic value "0" when the reference speed Vref is abnormal, irrespective of the output of the AND circuits 31b, 31e, and the acceleration detection and control section 26 is therefore selected. The changeover control sections 28c, 28f of the No. 3 shaft and No. 6 shaft include AND circuits 31c, 31f that input a backward travel instruction and shaft number, and AND circuits 34c, 34f that input the output of the AND circuits 31c, 31f and the output of the reference speed abnormality detection sections 33c, 33f. The reference speed abnormality detection sections 33c, 33f output logic value "0" when the reference speed Vref is abnormal. Consequently, if the reference speed Vref is abnormal, the output of the AND circuits 34c, 34f becomes logic value "0" irrespective of the output of the AND circuits 31c, 31f, and the acceleration detection and control section 26 is therefore selected. FIG. 8 is a block layout diagram of reference speed abnormality detection sections 33a to 33f in the second embodiment of the present invention. The reference speed Vref from the reference speed calculation section 20 is input to a comparator 35, and is compared with a first set value by the comparator 35. A decision is thereby made as to whether or not the reference speed Vref is within a first set value range (for example ± 0.5 Hz). If the period of continuance of the reference speed Vref being within the first set range is equal to or more than a set value (for example 1 sec) of an ON time element 36, the logic value "1" is output to the NAND circuit 37. Meanwhile, the speed signals Va to Vf of the motors 12a to 12f are input to a maximum value calculation section 38, and the maximum value of these speed signals Va to Vf is thereby obtained. The maximum value of the speed signals Va to Vf found by the maximum value calculation section 38 is input to a comparator 39 and, if the maximum value of the speed signals Va to Vf is equal to or more than a second set value (for example 2 Hz), the comparator 39 outputs logic value "1" to a NAND circuit 37. The output of the NAND circuit 37 therefore becomes logic value "0" if the reference speed Vref is within the first set range i.e. in the vicinity of zero and the maximum value of the speed signals Va to Vf is equal to or greater than the second set value i.e. if any of the speed signals Va to Vf are in an abnormal condition. Thus, if the speed signal Va to Vf of any of the motors 12a to 12f is abnormal, with the result that this stays at zero, the reference speed Vref also remains at zero after selection of the minimum value of the speed signals Va to Vf, so the torque of the motor that is the subject of slippage speed detection and control stays in a throttled condition i.e. the motor becomes disabled. Accordingly, if abnormality of the reference speed Vref is detected, the first and second and fourth and fifth motors are changed over from the slippage speed detection and control section 27 to the acceleration detection and control section 26. In this way, at least the inverters 11 of the motors 12 associated with the drive shafts other than the drive shaft whose speed signal V is abnormal can be actuated normally. With this second embodiment, when abnormality of the reference speed Vref is detected, all of the motors are changed over to the acceleration detection and control section 26, so that the inverters 11 of the drive shafts other than the drive shaft that is abnormal can be actuated normally. Anti-skid readhesion control can therefore be performed even if one or more of the drive shafts has become abnormal. The present invention may be applied in electric locomotives. WHAT IS CLAIMED IS: 1. A vehicle motor control device having as a motor driving wheels of a vehicle three motors per chassis and said motors being individually controlled by an inverter, said vehicle motor control device comprising: an acceleration detection and control section provided for each respective inverter and that throttles a torque on detecting increase of a rate of change with time of a speed signal of said motors above a prescribed value; a slippage speed detection and control section provided for each respective inverter and that throttles a torque in response to an amount of increase of a speed signal of said motor from a prescribed reference speed; and a changeover control section that changes over said inverter that controls said motor that is located rearmost in a direction of vehicle travel in each chassis so as to be controlled by said acceleration detection and control section and inverters that control the other two motors so as to be controlled by said slippage speed detection and control section. 2. The vehicle motor control device according to claim 1, wherein said changeover control section effects control of all of said inverters by said acceleration detection and control section if a prescribed reference speed is at or below a first set value even when a prescribed time has elapsed after inverter start-up, and a maximum value of said speed signals of respective motors has become equal to or greater than a second set value. 3. The vehicle motor control device according to claim 2, wherein said first set value is ± 0.5 Hz. 4. The vehicle motor control device according to claim 2, wherein said second set value is 2 Hz. 5. The vehicle motor control device according to claim 1, wherein three motors are provided in each case in two said chassis provided in each vehicle, and, of a first motor, second motor, third motor, fourth motor, fifth motor and sixth motor identified in a direction of travel of said vehicle, acceleration detection and control is performed in respect of said third motor and sixth motor and slippage speed detection and control is performed in respect of remaining other motors.

Full Text

TITLE OP THE INVENTION
VEHICLE MOTOR CONTROL DEVICE
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle motor control device for controlling drive of a rail vehicle.
2. Description of the Related Art
A vehicle motor control device that controls drive of a rail vehicle performs anti-skid readhesion (or re-adhesion) control in order to prevent skidding of the vehicle wheels. Such anti-skid readhesion control may be performed by the method of acceleration detection, in which anti-skid readhesion control is performed by detecting skidding by calculating the speed change rate of the vehicle shaft or motor shaft or by the method of slippage speed detection, in which skidding is detected by calculating the skidding speed (or slipping speed).
FIG. 1 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional acceleration detection method. FIG. 1 shows the case in which there are six wheel-driving motor shafts in a single vehicle, these being independently controlled by respective inverters.

The rotational speed of the motors 12a to 12f that are driven by the inverters 11a to llf is detected by rotational speed detectors (such as for example pulse generators or resolvers) 13a to 13f and input to anti-skid readhesion control sections 14a to 14f. The anti-skid readhesion control sections 14a to 14f have the same construction, so only the anti-skid readhesion section 14a will be described below.
The rotational speed (rotational number) of the motor 12a that is detected by the rotation speed detector (pulse generator) 13a is converted into a speed signal that is input to the speed calculation section 15a of the anti-skid readhesion control section 14a. The rate of change of the speed signal is found by inputting the speed signal found by the speed calculation section 15a to the acceleration detection section 16a. The acceleration detection section 16a then determines whether the rate of change of the speed signal is at or above a prescribed value: if the rate of change of the speed signal is at or above the prescribed value, the acceleration detection section 16a identifies (detects) the skidding condition; if the rate of change of the speed signal is less than the prescribed value, the acceleration detection section 16a identifies recovery. The torque throttling/recovery calculation section 17a calculates and outputs the amount of torque throttling or

recovery in accordance with the skidding identification signal of the acceleration detection section 16a.
The torque instruction pattern output section 18a outputs a torque instruction pattern: the output of the torque throttling/recovery calculation section 17a is output as the final torque instruction after being subtracted from the torque instruction pattern from the torque instruction pattern output section 18a by a subtracter 19a.
Next, FIG. 2 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional slippage speed detection method. FIG. 2 shows the case in which there are six wheel-driving motor shafts in a single vehicle, these being independently controlled by respective inverters.
The rotational speed of the motors 12a to 12f that are driven by the inverters lla to llf is detected by rotational speed detectors 13a to 13f and input to speed calculation sections 15a to 15f of anti-skid readhesion control sections 14a to 14f, where it is converted to a speed signal. The speed signals that are calculated by the speed calculation sections 15a to 15f are input to a reference speed calculation section 20, where a reference speed is calculated. The calculation of the reference speed may be performed by for example a method as illustrated in the Journal of the Electrical Association of Japan Industrial

Applications Section Vol. 121-D' No. 9. 2001 p 928 (Figure 11)
The reference speed calculated by the reference speed calculation section 20 is input to the subtracters 21a to 21f of the respective anti-skid readhesion control sections 14a to 14f, where the reference speed is subtracted from the speed signals of each motor shaft found by the speed calculation sections 15a to 15f, and the amount of deviation greater than zero is input to the preliminary delay amplification sections 22a to 22f. The outputs of the preliminary delay amplification sections 22a to 22f are subtracted from the torque instruction patterns from the torque instruction pattern output sections 18a to 18f and the results output as the final torque instruction.
Some references, such as for example Published Japanese Patent No. 3152785 (Laid-open Japanese Patent Application No, H. 6-261415) disclose arrangements wherein, when controlling individual controllers that separately control each motor of the vehicle motors, high precision control can be performed without affecting other motors even if skidding occurs in any one motor.
However, with a vehicle motor control device in which anti-skid readhesion control is performed by the conventional acceleration detection method, torque throttling in order to achieve readhesion is performed immediately in a positive fashion on detection of skidding,

so torque throttling tends to be abrupt and the amount of throttling tends to be large. Consequently, in cases where skidding occurs frequently, the average acceleration torque is greatly lowered, or the abrupt throttling of the torque that is performed for each shaft as mentioned in the Patent Publication referred to above may give rise to shifting of the shaft load, tending to cause skidding of other shafts.
On the other hand, in the case of a vehicle motor control device in which anti-skid readhesion control is performed by the conventional slippage speed detection method, the amount of torque throttling is determined in accordance with the amount of the slippage speed produced by the skidding, so, although the amount of torque throttling can be made smaller than in the case of the acceleration detection method, the torque throttling response is lowered due to the first-order lag element (or preliminary delay element). Consequently, a mode is generated in which readhesion is not reliably achieved, so there is a risk of destabilization of the reference speed if skidding continues in respect of all six shafts.
SUMMARY OF THE INVENTION
Accordingly, an advantage of an aspect of the present invention is to provide a novel vehicle motor control device whereby the amount of torque throttling on skidding is

reduced and stable acceleration performance is obtained without destabilization of the reference speed.
The above object can be achieved by a rotary electrical machine constructed as follows. Specifically, a vehicle motor control device having as motors driving the wheels of a vehicle three motors per chassis and further having inverters that individually control respective motors comprises:
an acceleration detection and control section provided for each respective inverter and that throttles the torque on detecting increase of the rate of change with time of the speed signal of the aforementioned motors above a prescribed value;
a slippage speed detection and control section provided for each respective inverter and that throttles the torque in response to the amount of increase of the speed signal of said motor from a prescribed reference speed; and
a changeover control section that changes over the inverter that controls the motor that is located rearmost in the direction of vehicle travel in each chassis so as to be controlled by said acceleration detection and control section and the inverters that control the other two motors so as to be controlled by said slippage speed detection and control section.
According to the present invention, even under conditions of poor adhesion between the rail and vehicle

wheels such that skidding occurs frequently, lowering of the acceleration performance can be suppressed, since the minimum torque throttling amount in accordance with the amount of skidding speed suffices, and a stable reference speed is obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional acceleration detection method.
FIG. 2 is a layout diagram of a vehicle motor control device that performs anti-skid readhesion control using a conventional slippage speed detection method.
FIG. 3 is a block diagram of the case where a vehicle motor control device according to a first embodiment of the present invention is applied to a vehicle.
FIG. 4 is a detailed block diagram of a vehicle motor control device according to a first embodiment of the present invention.
FIG. 5 is an operating waveform diagram showing the operation in the case of an acceleration detection and

control method with an acceleration detection and control section according to a first embodiment of the present invention.
FIG. 6 is an operating waveform diagram of a slippage speed detection and control method with a slippage speed detection and control section according to a first embodiment of the present invention.
FIG. 7 is a detailed block layout diagram of a vehicle motor control device according to a second embodiment of the present invention.
FIG. 8 is a block layout diagram of a reference speed abnormality detection section according to a second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 3 thereof, two embodiments of the present invention will be described.
(First embodiment)
FIG. 3 is a block diagram of the case where a vehicle motor control device according to a first embodiment of the present invention is applied to a vehicle. In the lower part of the vehicle body 23 of the vehicle, there are provided two chassis frames 24A, 24B; vehicle shafts 25a, 25b, 25c

are mounted on the chassis frame 24a and vehicle shafts 25d, 25e, 25f are mounted on the chassis frame 24B. These vehicle shafts are respectively driven by motors 12a to 12f. Hereinbelow, the motor shafts respectively corresponding to the six vehicle shafts 25a to 25f will be described as the No. 1 shaft, No. 2 shaft, No. 3 shaft, No. 4 shaft, No. 5 shaft and No. 6 shaft, from the direction of travel in the case of an instruction for forward travel.
The rotational speeds of the motors 12a to 12f corresponding to the respective shafts are respectively detected by the rotational speed detectors 13a to 13f and input to the anti-skid readhesion control sections 14a to 14f. The anti-skid readhesion control sections 14a to 14f include acceleration detection and control sections 26a to 26f, slippage speed detection and control sections 27a to 27f and changeover control sections 28a to 28f.
The acceleration detection and control sections 26a to 26f perform anti-skid readhesion control by throttling the torque on detection of skidding; this detection is performed by sensing increase of the rate of change with time of the speed signal of the motors 12a to 12f above a prescribed value. In contrast, the slippage speed detection and control sections 27a to 27f perform anti-skid readhesion control by throttling the torque in response to the amount of increase of the speed signals Va to Vf from the motors 12a to 12f from a prescribed reference speed Vref. The prescribed

reference speed Vref is found by calculation performed by the reference speed calculation section 20. In this embodiment of the invention, the minimum value of the speed signals Va to Vf of the motors 12a to 12f is selected as the reference speed.
Next, the changeover control sections 28a to 28f effect changeover between the acceleration detection and control sections 26a to 26f and the slippage speed detection and control sections 27a to 27f; normally, by using the acceleration detection and control sections 26a to 26f, they control the inverter that controls the motor that is positioned rearmost in the direction of travel of the vehicle for each chassis and effect changeover such that the inverters that control the other two motors are controlled by the slippage speed detection and control sections 27a to 27f. For example, if the direction of travel of the vehicle is the leftwards direction in FIG. 1, it is arranged that the motor 12c (12f) that is positioned rearmost in the direction of travel of the vehicle on a chassis is controlled by the acceleration detection and control sections 26a to 26f, while the other two motors 12a, 12b (12d, 12e) are controlled by the slippage speed detection and control sections 27a to 27f.
FIG. 4 is a detailed block layout diagram of a vehicle motor control device according to a first embodiment of the present invention. The acceleration detection and control

sections 26a to 26f and the slippage speed detection and control sections 27a to 27f of the anti-skid readhesion control sections 14a to 14f are of the same construction, so only the acceleration detection and control section 26a and the slippage speed detection and control section 27a of the anti-skid readhesion control section 14a will be described.
The acceleration detection and control section 26a includes a speed calculation section 15a, an acceleration detection section 16a, a torque throttling/recovery calculation section 17a, a switch 29a, a subtracter 19a, and a torque instruction pattern output section 18a. Also, the slippage speed detection and control section 27a includes a speed calculation section 15a, subtracter 30a, preliminary delay amplifier 22a, switch 29a, subtracter 19a, and torque instruction pattern output section 18a. Changeover of the acceleration detection and control section 26a and slippage speed detection and control section 27a is performed by changeover of the switch 29a. This changeover is performed by the changeover control section 28a.
First of all, the operation when the acceleration detection and control section 26a is selected by the switch 29a will be described. The speed signal Va converted by the speed calculation section 15a is input to the acceleration detection section 16a, and the change rate of the speed signal Va is thereby found. If the rate of change of this speed signal Va exceeds the prescribed value, skidding is

identified, and if the prescribed value is not exceeded, recovery is identified. The torque throttling/recovery calculation section 17a calculates and outputs a torque throttling amount or recovery amount in accordance with the skidding identification signal obtained in the acceleration detection section 16a to the subtracter 19a through the switch 29a. The subtracter 19a compares this with the torque instruction pattern from the torque instruction pattern output section 18a, and outputs a torque instruction corresponding to the difference thereof.
FIG. 5 is an operating waveform diagram showing the operation of the acceleration detection and control method in the acceleration detection and control section 26a. When adhesion between the vehicle wheels and the rail drops due for example to rain, causing the vehicle wheels to skid, there is an abrupt increase in the speed change rate, so, at the time-point tl where the speed change rate exceeds a certain set value A, a skidding detection flag is set, causing torque throttling to be commenced with a comparatively steep gradient. Then, at the time-point t2 where the speed change rate has become less than a given set value B, the skid detection flag is removed, allowing operation to be performed in which restoration is slowly effected to the original torque instruction, with a preliminary delay constant provided by a time constant i.

Substantially reliable readhesion can therefore be performed with a motor shaft controlled in this way.
Next, the operation in the case where the slippage speed detection and control section 21 a is selected by the switch 29a will be described. The speed signal Va converted by the speed calculation section 15a is input to the subtracter 30a, The subtracter 30a inputs a reference speed Vref from the reference speed calculation section 20, finds the deviation of the speed signal Va and the reference speed Vref, and outputs this deviation to the preliminary delay amplification section 22a. The reference speed calculation section 20 selects the minimum value of the speed signals Va to Vf calculated by the speed calculation sections 15a to 15f of the No. 1 shaft to No. 6 shaft, and outputs this as the reference speed Vref.
The preliminary delay amplification section 22a finds the torque throttling amount from the deviation greater than zero of the speed signal Va and reference speed Vref and outputs the result to the subtracter 19a through the switch 29a. The subtracter compares this with the torque instruction pattern from the torque instruction pattern output section 18a, and outputs a torque instruction in accordance with the difference thereof.
FIG. 6 is an operational waveform diagram showing operation in accordance with the slippage speed detection and control method in the slippage speed detection and

control section 27a. When at the time-point t1 the speed signal Va of the motor 12a increases by more than a certain value from the reference speed Vref as a result of skidding of the vehicle wheels, the speed signal Va is subtracted from the torque instruction pattern in accordance with the amount of this increase. The torque throttling amount becomes zero at the time point t2 where the deviation of the speed signal Va and the reference speed Vref of the motor 12a has become less than a certain value due to readhesion as a result of such torque throttling. Under such speed detection control, the torque is continuously controlled by the deviation amount while allowing slippage of the vehicle wheels, so, under conditions in which the rail adhesion has decreased, the speed signal Va of the motor 12a is normally larger than the reference speed Vref.
Next, changeover of the acceleration detection and control sections 26a to 26f and the slippage speed detection and control sections 27a to 21 £ will be described. Changeover of the acceleration detection and control sections 26a to 26f and the slippage speed detection and control sections 27a to 27f is performed by the changeover control sections 28a to 28f.
The changeover control section 28a of the anti-skid readhesion control section 14a associated with the No. 1 shaft performs changeover under the same condition as the changeover control section 28d of the anti-skid readhesion

control section 14d associated with the No. 4 shaft. Likewise, the changeover section 28b of the anti-skid readhesion control section 14b associated with the No. 2 shaft and the changeover control section 28e of the antiskid readhesion control section 14e associated with the No. 5 shaft perform changeover under the same condition and the changeover section 28c of the anti-skid readhesion control section 14c associated with the No. 3 shaft and the changeover control section 28f of the anti-skid readhesion control section 14f associated with the No. 6 shaft perform changeover under the same condition.
Regarding the No. 1 shaft and No. 4 shaft, the changeover control sections 28a, 28d arrive at their decisions on input of the forward travel instruction and shaft number to the AND circuits 31a, 31d. In the event of a forward drive instruction, the AND circuits 31a, 31d of the changeover control sections 28a, 28d assume logic value "1" and the switches 29a, 29d are changed over to the side of the slippage speed detection and control section 27a. Contrariwise, in the event of a backward travel instruction, the AND circuits 31a, 31d of the changeover control sections 28a, 28d become logic value "0" and the switches 29a, 29d are changed over to the side of the acceleration detection and control section 26a.
Regarding the No. 2 and No. 5 shaft, the changeover control sections 28b, 28e arrive at their decisions by input

of a forward travel or backward travel instruction by the OR circuits 32b, 32e and by input of the outputs of the OR circuits 32b, 32e and the shaft numbers to the AND circuits 31b, 31e. Consequently, both in the event of a forward travel instruction and in the event of a backward travel instruction, the logic value becomes "1" and the switches 29a, 29d are changed over to the side of the slippage speed detection and control section 27a.
Regarding the No. 3 shaft and No. 6 shaft, the changeover control sections 28c, 28f arrive at their decisions by input of the backward travel instruction and shaft number to the AND circuits 31c, 31f. In the event of a backward travel instruction, the AND circuits 31c, 31f of the changeover control sections 28c, 28f become logic value "1" and the switches 29c, 29f are changed over to the side of the slippage speed detection and control section 27a. Contrariwise, in the event of a forward travel instruction, the AND circuits 31c, 31f of the changeover control sections 28c, 28f become logic value "0", and the switches 29c, 29f are changed over to the side of the acceleration detection and control section 26a.
In this way, the first and second motors 12a, 12b and the fourth and fifth motors 12d, 12e with respect to the direction of forward travel are controlled by the slippage speed detection and control section 27, while the third and

sixth motors 12c, 12f are controlled by the acceleration detection and control section 26.
The reason for this is in order to obtain a stable reference speed, in view of the fact that, considering shifting of the shaft load of the vehicle, the magnitude of the shaft load is a minimum in the case of the first motor shaft and thereafter increases in the order: second, fourth, third, fifth and sixth shafts. In other words, reliable readhesion can be achieved by employing acceleration detection and control as the control method for the third and sixth motors, which are the tail motors, where the shaft load is largest in each chassis. By employing slippage speed detection and control for the other shafts, overall torque throttling is minimized.
With the first embodiment, by using the acceleration detection and control section 26 to control the third and sixth motors, which are the tail motors, where the shaft load is largest in each chassis, and using the slippage speed detection and control section 27 to control the other shafts, reliable readhesion of the vehicle wheels with the rails can be achieved, and shifting of the shaft load can be prevented from provoking skidding of the other shafts, thereby making it possible to minimize the amount of overall torque throttling.
(Second embodiment)

FIG. 7 is a detailed block layout diagram of a vehicle motor control device according to a second embodiment of the present invention. In this second embodiment, in contrast to the first embodiment shown in FIG. 4, reference speed abnormality detection sections 33a to 33f are provided in the changeover control sections 28a to 28f. Elements which are the same as in the case of FIG. 4 are given the same reference symbols and repeated description is dispensed with.
The changeover control sections 28a, 28d of the No. I shaft and No. 4 shaft include AND circuits 31a, 31d that input a forward travel instruction and shaft number, and AND circuits 34a, 34d that input the output of the AND circuits 31a, 31d and the output of reference speed abnormality detection sections 33a, 33d. When the reference speed Vref of the reference speed abnormality detection sections 33a, 33d is abnormal, a logic value "0" is output. Consequently, when the reference speed Vref is abnormal, the outputs of the AND circuits 34a, 34d become logic value "0" irrespective of the output of the AND circuits 31a, 31d, so the acceleration detection and control section 26 is selected.
The changeover control sections 28b, 28e of the No. 2 shaft and No. 5 shaft include OR circuits 32b, 32e that input a forward travel instruction and backward travel instruction, AND circuits 31b, 31e that input the outputs of the OR circuits 32b, 32e and the shaft number, and AND

circuits 34b, 34e that input the output of the AND circuits 31b, 31e and the output of the reference speed abnormality detection sections 33b, 33e. The reference speed abnormality detection sections 33b, 33e output logic value "0" when the reference speed Vref is abnormal. Consequently, the output of the AND circuits 34b, 34e becomes logic value "0" when the reference speed Vref is abnormal, irrespective of the output of the AND circuits 31b, 31e, and the acceleration detection and control section 26 is therefore selected.
The changeover control sections 28c, 28f of the No. 3 shaft and No. 6 shaft include AND circuits 31c, 31f that input a backward travel instruction and shaft number, and AND circuits 34c, 34f that input the output of the AND circuits 31c, 31f and the output of the reference speed abnormality detection sections 33c, 33f. The reference speed abnormality detection sections 33c, 33f output logic value "0" when the reference speed Vref is abnormal. Consequently, if the reference speed Vref is abnormal, the output of the AND circuits 34c, 34f becomes logic value "0" irrespective of the output of the AND circuits 31c, 31f, and the acceleration detection and control section 26 is therefore selected.
FIG. 8 is a block layout diagram of reference speed abnormality detection sections 33a to 33f in the second embodiment of the present invention. The reference speed Vref from the reference speed calculation section 20 is

input to a comparator 35, and is compared with a first set value by the comparator 35. A decision is thereby made as to whether or not the reference speed Vref is within a first set value range (for example ± 0.5 Hz). If the period of continuance of the reference speed Vref being within the first set range is equal to or more than a set value (for example 1 sec) of an ON time element 36, the logic value "1" is output to the NAND circuit 37.
Meanwhile, the speed signals Va to Vf of the motors 12a to 12f are input to a maximum value calculation section 38, and the maximum value of these speed signals Va to Vf is thereby obtained. The maximum value of the speed signals Va to Vf found by the maximum value calculation section 38 is input to a comparator 39 and, if the maximum value of the speed signals Va to Vf is equal to or more than a second set value (for example 2 Hz), the comparator 39 outputs logic value "1" to a NAND circuit 37. The output of the NAND circuit 37 therefore becomes logic value "0" if the reference speed Vref is within the first set range i.e. in the vicinity of zero and the maximum value of the speed signals Va to Vf is equal to or greater than the second set value i.e. if any of the speed signals Va to Vf are in an abnormal condition.
Thus, if the speed signal Va to Vf of any of the motors 12a to 12f is abnormal, with the result that this stays at zero, the reference speed Vref also remains at zero after

selection of the minimum value of the speed signals Va to Vf, so the torque of the motor that is the subject of slippage speed detection and control stays in a throttled condition i.e. the motor becomes disabled.
Accordingly, if abnormality of the reference speed Vref is detected, the first and second and fourth and fifth motors are changed over from the slippage speed detection and control section 27 to the acceleration detection and control section 26. In this way, at least the inverters 11 of the motors 12 associated with the drive shafts other than the drive shaft whose speed signal V is abnormal can be actuated normally.
With this second embodiment, when abnormality of the reference speed Vref is detected, all of the motors are changed over to the acceleration detection and control section 26, so that the inverters 11 of the drive shafts other than the drive shaft that is abnormal can be actuated normally. Anti-skid readhesion control can therefore be performed even if one or more of the drive shafts has become abnormal.
The present invention may be applied in electric locomotives.

WHAT IS CLAIMED IS:
1. A vehicle motor control device having as a motor
driving wheels of a vehicle three motors per chassis and
said motors being individually controlled by an inverter,
said vehicle motor control device comprising:
an acceleration detection and control section provided for each respective inverter and that throttles a torque on detecting increase of a rate of change with time of a speed signal of said motors above a prescribed value;
a slippage speed detection and control section provided for each respective inverter and that throttles a torque in response to an amount of increase of a speed signal of said motor from a prescribed reference speed; and
a changeover control section that changes over said inverter that controls said motor that is located rearmost in a direction of vehicle travel in each chassis so as to be controlled by said acceleration detection and control section and inverters that control the other two motors so as to be controlled by said slippage speed detection and control section.
2. The vehicle motor control device according to claim 1,
wherein said changeover control section effects control
of all of said inverters by said acceleration detection and control section if a prescribed reference speed is at or

below a first set value even when a prescribed time has elapsed after inverter start-up, and a maximum value of said speed signals of respective motors has become equal to or greater than a second set value.
3. The vehicle motor control device according to claim 2,
wherein said first set value is ± 0.5 Hz.
4. The vehicle motor control device according to claim 2,
wherein said second set value is 2 Hz.
5. The vehicle motor control device according to claim 1,
wherein three motors are provided in each case in two
said chassis provided in each vehicle, and, of a first motor, second motor, third motor, fourth motor, fifth motor and sixth motor identified in a direction of travel of said vehicle, acceleration detection and control is performed in respect of said third motor and sixth motor and slippage speed detection and control is performed in respect of remaining other motors.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=uaJj/Ty6BZZK6lMJxoXmhg==&loc=+mN2fYxnTC4l0fUd8W4CAA==

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Patent Number

270313

Indian Patent Application Number

1031/DEL/2007

PG Journal Number

50/2015

Publication Date

11-Dec-2015

Grant Date

10-Dec-2015

Date of Filing

11-May-2007

Name of Patentee

KABUSHIKI KAISHA TOSHIBA

Applicant Address

1-1 SHIBAURA 1-CHOME, MINATO-KU, TOKYO, 105-8001, JAPAN

Inventors:

#	Inventor's Name	Inventor's Address
1	TODA SHINICHI	C/O INTELLECTUAL PROPERTY DIVISION, TOSHIBA CORPORATION, OF 1-1 SHIBAURA 1-CHOME, MINATO-KU, TOKYO, 105-8001, JAPAN
2	YASUOKA IKUO	C/O INTELLECTUAL PROPERTY DIVISION, TOSHIBA CORPORATION, OF 1-1 SHIBAURA 1-CHOME, MINATO-KU, TOKYO, 105-8001, JAPAN
3	NAKAZAWA YOSUKE	C/O INTELLECTUAL PROPERTY DIVISION, TOSHIBA CORPORATION, OF 1-1 SHIBAURA 1-CHOME, MINATO-KU, TOKYO, 105-8001, JAPAN

PCT International Classification Number

B60T13/18

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	P2006-142578	2006-05-23	Japan