Dynamic Modeling and Force Control of a Redundant Robot for Polishing Applications
Sprache des Vortragstitels:
85th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM)
Sprache des Tagungstitel:
For many robotic applications with tasks such as cutting, assembly or polishing, it is necessary to get in contact with the surrounding. In this paper a redundant robot with seven degrees of freedom in a metal polishing task is considered. For simulation as well as for the controller design a dynamic model of the robot and a contact model are required. The equations of motion of the robot are calculated by the Projection Equation in subsystem representation and the contact model contains linear tool elasticities and work piece elasticities. In the case of the polishing task, a constant contact force during the process is required even if the robot moves along a trajectory. Thus some degrees of freedom of the robot tool center point (TCP) have to be position controlled while the other ones have to be force controlled. The redundant robot offers the possibility to avoid singular positions or to maximize the available end-effector forces within the inverse kinematics and is therefore best suited for polishing large objects. The actual process forces are measured with a six axes force-torque-sensor mounted at the TCP. These forces are used in a parallel force/position control law to achieve the desired
behavior. Results from simulation as well as from measurements of a test arrangement are compared to each other.