Title of Invention

MECHATRONIC TEST RIG FOR ACTUATORS

Abstract

This invention relates to a mechatronic test rig for actuators. It consists of a loading actuator associated with position sensing means and interfaced to an electronically derivable load test actuator mounted between a fixed end plate and a movable platform. The movable platform has a load sensing means and means for measuring acceleration. A command generator is connected to a controller capable of feeding input parameters. The controller is capable of generating real time drive voltage for loading factors based on commands received from the command generator.

Full Text

Technical Field: The invention relates to a mechatronic test rig for actuators in which any type of load dynamics can be realized mechatronically for evaluating actuation system performance under various loading conditions. Background and Prior Art: Different types of position servomechanisms are used in industries and aerospace mechanisms to control the position of tools, thrusters etc. in the presence of uncertain load disturbances. These position servo mechanisms are powered either by electromechanical or electro hydraulic actuators which convert electrical or hydraulic energy into mechanical energy as per the servo system command. During the development and qualification phases of these actuators for position servomechanisms, they are to be tested for performance validation under an equivalent mechanical loading environment similar to the real application. Currently, this is being carried out using dedicated load test rigs where the load dynamics is simulated using the equivalent mass, spring etc. For example, for testing servo actuators employed for thrust vector control of rockets and missiles, inertia simulated rocket engines are currently used. This scheme requires different loading devices to be fabricated for different actuation systems and even a small change in one of the load parameters like inertia may call for the total change of the loading device. The present invention relates to a Universal test rig for actuators in which any type of load dynamics can be realized mechatronically for evaluating the actuation system performance under various loading conditions. Contrary to the prior-art test beds, the mechanical load parameters like mass, spring stiffness, damping etc. can be directly programmed as input parameters to generate the corresponding load reaction force in real time using the present invention. Thus the present invention can cater to the loading requirement of a wide range of actuators having different stroke and force ranges without changing the loading device. Japanese Patent JP 7134080 discloses the invention of a 'Hydraulic Load Simulator' which can generate a load equivalent to a load generated in a hydraulic actuator at a time of operating an actual machine against a hydraulic system. This invention simulates the hydraulic pressure load felt by the hydraulic flow control valves when it is actually connected to the actuator. However, the present invention differs from this as it simulates the mechanical load felt by the actuator instead of the hydraulic pressure load. Objects of the invention: The primary object of the present invention is to provide a Universal test rig for linear actuators with wide force and stroke ranges using a common loading actuator and a mechatronic control loop in which load dynamics constants can be programmed as input parameters. Yet another object of the present invention is to synthesize any nonlinear load dynamics mechatronically which can be expressed as a function of actuator position, velocity and acceleration. Another object of the present invention is to provide a test rig to estimate the dynamic stiffness characteristics of a liner actuation system against load disturbance. Another object of the present invention is to provide a test rig to estimate the sensitivity of actuation system with respect to load parameter variation. Yet another object of the present invention is to provide a system modeling test bed to extract the internal parameters of actuator under test. A further object is to provide a test bed in which benchmark control problems can be easily synthesized to validate advanced control algorithms Summary of invention: The present invention namely the mechatronic test rig for actuators is a Universal test rig in which any generic load dynamics including nonlinearities and external load disturbance forces can be directly programmed as input parameters or signals to generate the equivalent load reaction force in real time. The mechanical realization of this reaction force is carried out using a high power loading actuator controlled by a high bandwidth force servo loop. This device uses position, acceleration and force sensors to generate the real time drive command to the loading actuator. The computation of force command and the compensation of force servo loop are carried out by a digital signal processor based control unit. The loading actuator is mechanically interfaced to the actuator under test through a movable platform, which can freely move in the direction of actuation. The test actuator is connected to the movable platform through force sensor, the output of which is used for feedback and control. This invention relates to a mechatronic test rig for actuators comprising a loading actuator one end of which is fixedly mounted on an end plate, said loading actuator associated with position sensing means and provided with a DC torque motor interfacing with an electronically drivable load test actuator, the electronic drive through a slidably movable platform, said test actuator is mounted between a fixed end plate and said movable platform, said movable platform having load sensing means and means for measuring acceleration, a controller connected to a command generator provided with means for feeding input parameter valves like load mass, load stiffness, load damping, load friction, external load force and the like as functions of time and load displacement said controller capable of generating real time drive voltage for such loading factors based on command from said command generator and the force feed back received from said load sensing means. Detailed description of the invention: Fig.l illustrates a preferred embodiment of mechatronic test rig actuator of this invention. The loading actuator (1) generates the required load reaction force and is interfaced to the test actuator (2) through a movable platform (3) and a loading force measuring device (7). The other end of loading actuator is mounted on the fixed end plate (5). The loading actuator (1) uses a DC torque motor and a ball screw mechanism to generate the loading force according to the drive current from the loading actuator drive electronics (12). The test actuator (2) is driven by its own drive electronics (13) and is mounted between the fixed end plate (4) and the moving platform (3) through the load sensing device (7). The movable interface platform (3) slides freely along the guides (6) using appropriate linear motion bearing mechanism. An acceleration measuring device (8) mounted on the moving interface platform senses the acceleration of the moving ends of the actuators which is equivalent to the load acceleration. A position sensing device (9) associated with the loading actuator measuring the displacement of the interface platform (3) gives the load displacement. The load velocity is derived from load acceleration and load position by a state observer. The load parameter values like load mass, load stiffness, load damping, load friction, external load force as a function of time or load displacement can be given an input parameters by the system operator (11) into the command generator device (10). The command generator device (10) sends the real time load force command to the force servo loop controller (12) based on the real time data of position, velocity and acceleration of the load. The force loop controller (12) generates the real time drive voltage for the loading actuator torque motor based on the force command from (10) and force feedback from (7). The bandwidth of the force servo loop is one order higher than the bandwidth of the test actuator (2) so that the effect of loading force generated by the loading actuator resembles close to the actual load reaction force expected in the real operation of the test actuator. The following are the advantages of the present invention over the prior art test beds. 1) There is no need of dedicated test rigs for each type of load and actuator. The present invention provides a Universal test bed with programmable load dynamics and can accommodate actuators having wide stroke and force ranges. 2) Any nonlinear load dynamics and time dependent external load disturbance force can be generated using present invention without any extra hardware requirement. 3) Dynamic stiffness characteristics and servo loop robustness can be estimated using the present invention without any extra hardware requirement. 4) The present invention due to its programmable feature can be used as an autonomous test rig for modeling the test actuator and also for synthesizing benchmark control problems. WE CLAIM: 1. A mechatronic test rig for actuators comprising a loading actuator one end of which is fixedly mounted on an end plate, said loading actuator associated with position sensing means and provided with a DC torque motor interfacing with an electronically drivable load test actuator, the electronic drive through a slidably movable platform, said test actuator is mounted between a fixed end plate and said movable platform, said movable platform having load sensing means and means for measuring acceleration, a controller connected to a command generator provided with means for feeding input parameter valves like load mass, load stiffness, load damping, load friction, external load force and the like as functions of time and load displacement said controller capable of generating real time drive voltage for such loading factors based on command from said command generator and the force feed back received from said load sensing means. 2. The mechatronic test rig as claimed in claim 1, wherein said loading actuator is provided with a DC torque motor and a ball screw means to generate loading force on the basis of the drive current from its electronic drive means. 3. The mechatronic test rig as claimed in claim 1, wherein said load test actuator is a linear actuator. 4. The mechatronic test rig as claimed in claims 1 to 3, wherein said controller is a digital signal processor capable of executing control algorithms.

Documents:

110-CHE-2006 CORRESPONDENCE OTHERS 13-08-2013.pdf

110-CHE-2006 AMENDED CLAIMS 22-08-2014.pdf

110-CHE-2006 AMENDED PAGES OF SPECIFICATION 22-08-2014.pdf

110-CHE-2006 EXAMINATION REPORT REPLY RECEIVED 22-08-2014.pdf

110-CHE-2006 CORRESPONDENCE OTHERS.pdf

110-CHE-2006 FORM 18.pdf

110-che-2006-abstract.pdf

110-che-2006-claims.pdf

110-che-2006-correspondnece-others.pdf

110-che-2006-description(complete).pdf

110-che-2006-drawings.pdf

110-che-2006-form 1.pdf

110-che-2006-form 26.pdf

110-che-2006-form 3.pdf