Optimization and control of an energy-efficient vibration-driven robot

Abstract

Vibration-driven robots are innovative mechanical systems that exhibit a wide range of capabilities and applications due to their simple propellers. The applications of these robots span from clearing debris after an incident, traversing pipelines for inspection and maintenance, or medical purposes. In this paper, optimization and motion control of an energy-efficient two-module vibration-driven robot are investigated. The robot contains two blocks connected by a spring as its main body, and an unbalanced rotating mass to drive the robot rectilinearly. At first, the governing dynamic equations of the robot are derived and solved using MATLAB/Simulink. Then, the dynamic model of the robot is verified by comparing the obtained results with the simulation results from MSC Adams. Subsequently, a parametric study is conducted to investigate the effect of various physical parameters of the robot on its average velocity and consumed energy. Afterward, optimization variables are determined and a proper objective function is considered. By performing an optimization process using a genetic algorithm (NSGA-II), optimal parameters of the robot are obtained. Moreover, for motion control of the optimized robot, two control schemes, PID and Fractional Order PID, are designed. To evaluate and compare the performance of the proposed controllers, parameters of both controllers are optimized using a genetic algorithm in which both tracking error and control input are minimized, simultaneously. Finally, tracking error and control effort of the mentioned controllers for motion control of the robot are compared and discussed.