Modelling and Simulation of Robot Arm Interaction Forces Using Impedance Control

In this paper we present the implementation of a Cartesian impedance control method to regulate the interaction forces between a robotic arm and the environment. A complete description of the procedure to model and control both a two-link planar robot arm and its interaction with the environment is detailed and simulated using MATLAB/Simulink; from the generation of a mechanical model in SimMechanics (MATLAB), the description and tuning of a dynamic model-based controller to cancel-out the non-linearities present on the dynamic model of the robot, the modelling of an environment, and finally the control of the interaction forces making use of a Cartesian impedance control method. This type of control adjusts the dynamic behaviour of the robot manipulator when contacting the environment, basically controlling stiffness and damping of the interaction rather than the precise contact forces. Its implementation in the Cartesian Space permits future use of the results in an industrial robot, whose internal joint and torque controllers are commonly not accessible.