Optimal Nonlinear PID Control of a Micro-Robot Equipped with Vibratory Actuator Using Ant Colony Algorithm: Simulation and Experiment

In this paper, an optimal nonlinear control scheme based on the application of ant colony optimization (ACO) is applied to a micro-robot equipped with vibratory actuators. Accordingly, two small vibrating motors are utilized to run the micro-robot and the motion principle of stick-slip is used for locomotion purpose. First, a dynamic model of the micro-robot is derived considering the stiffness of the robot’s legs. Then, the influences of robot mass and length of legs on micro-robot motion are studied using simulation. Next, an optimal linear PID control scheme is applied to the micro-robot system. However, it is found that this control method does not have an acceptable performance when friction is low or the system is under disturbance. Consequently, an ACO-based optimal nonlinear PID control is proposed to cope with the mentioned drawbacks as the main contribution of the paper. Afterwards, the performance of both control techniques is compared through simulation. Finally, the micro-robot is developed and experimentally evaluated. It is found that the experimental results are in a good agreement with some of the simulation outcomes through which the validity of the mathematical scheme as well as the feasibility of design is affirmed.