Methods of Compensation of Mechanical Feedback in the Operation of Electric-Drive Position Servosystems

摘要

The methods of mechanical feedback compensation in the operation of single-channel electric-drive systems with rigid kinematics, which implement position-based servocontrol of production machines (metal-working machines, robots, manipulators, and aggregated processing equipment in the chemical, paper-making, textiles, and other industries) are considered. An analysis is carried out of a technical solution based on the joint use of a change in the structure of the position controller with the switching of its integral input when the feedback is opened and the introduction of additional stabilizing feedback on the difference in the angular displacements of the motor shaft and the working body to the input of the current controller in the subordinate axis position control system of the follow-up electric drive. It is established that an equivalent alternative to changing the structure of the position controller depending on the feedback state is the corresponding replacement of working-body position feedback with motor-shaft angular displacement feedback while maintaining stabilizing feedback on the difference in the angular displacements of the working body and the electric motor. The advantage of the second approach is that the system is much less sensitive to inaccurate adjustment of the feedback monitor in the control device to the actual feedback size in the power transmission, as well as to possible feedback variations during equipment operation. Improving the accuracy of the movement of the working body in the final stage of following and positioning mode for both variants of the system can be achieved through additional switching elements providing forced activation of the integrator in the structure of the position controller in the first version of the control system or working-body position feedback in the second version. The effectiveness of the considered control systems of the follow-up electric drive is confirmed by the results of mathematical modeling in the MATLAB software package and full-scale tests on a multifunctional test bench.