Tracking control of parallel manipulator with 3-DOF

A parallel three degrees of freedom (3-DOF) manipulator known as Maryland manipulator is considered in this paper. The manipulator model considered in this paper is more practical because the offset lengths are not taken zero. The trajectory tracking control of the Maryland manipulator is done using linear?quadratic regulator (LQR) based proportional?integral?derivative (PID) controller. Three sequential trajectories are used to provide complete dynamic analysis of the manipulator. The manipulator considered here is more practical because the offset lengths are not taken zero unlike previous research articles. The motivation behind using PID controller is its simplicity and effectiveness. The manipulator is a highly coupled and nonlinear system so the correct determination of control signal is very important to achieve good tracking performance. The process for selecting the PID parameters is discussed in detail and the simulations results are used to show the efficacy of the controller.