Implementation and Testing of Force Control on a Spherical Articulated Manipulator

Robotic manipulators, a complex research topic consisting of nonlinear dynamics and control, have a wide industrial application that requires stability and high precision of the end-effector. Apart from the internal forces, external disturbances of the manipulator can cause a deviation from its desired state, affecting the overall stability and trajectory during the process. Therefore, a robust feedback control system is essential to ensure accurate maneuvering to the desired target position. Position controllers such as the Proportional-Integral-Derivative (PID) controller and the Linear Quadratic Regulator (LQR) controller are generally used for all robotic operations. In this work, we have implemented force-based impedance control using the manipulator’s simplified Lagrangian-Euler dynamics (LE) and we have compared the performance of 3 degrees of freedom (DoF) articulated robotic manipulators by applying the three control algorithms in MATLAB-Simulink and ROS-Gazebo simulators. The manipulator’s performance is tested for point-to-point motion subjected to disturbances and the simulation results shows that the impedance control has a higher tolerance to high perturbations than the classical PID and optimal LQR controllers. The results also demonstrate that the force-based controller is more suitable for higher-order linked systems in industrial applications than the optimal controller.