Position control of Stewart platform with electric linear actuator

Abstract

In recent decades, several technological applications have depended on manipulators like Stewart platform due to its accuracy and precision. Based on actuation type, Stewart platforms could be rotary or linearly actuated. Electric linear actuators are devices commonly consist of DC or AC motors coupled with lead screw or mechanism of gears and spindle which are used to convert rotary motion into linear (push or pull) motion. To increase accuracy and precision and achieve the desired linear actuator response, controllers should be used. The main aspiration of this work is to investigate the feasibility of using PID controllers for position control of Stewart platform with linear actuators. The mathematical model has been derived and the model transfer function has been obtained. To meet the required response of performance characteristics, the PID controller has been designed based on analysis of root-locus. Model simulation analysis has been carried out on both MATLAB and Simulink. For the electric linear actuator, comparison between the obtained response and the results of Ziegler-Nichols tuning method has been discussed on basis of the specifications of the time response. The PID controller parameters for the electric linear actuator has been tested experimentally and compared with simulation results.