Variable structure control of a redundant robotic manipulator

Absrracr: A variable structure system controller is developed to achieve set-point control and trajectory control of a redundant robotic manipulator for automated grinding. Precise control of a grinding robot is challenging because the system dynamics are highly coupled and nonlinear. Moreover, control parameters of the system are configuration dependent and difficult to accurately model. Variable structure systems (VSS) are robust to variations of system parameters and external disturbances, and they do not require accurate modeling. VSS implementation provides an attractive alternative. A control law based on VSS and sliding mode control is described. Redundancy results in non-uniqueness of the inverse kinematic and dynamic solutions, so that non-teaching control methods are difficult to implement. To overcome this difficulty, we propose method for regulation and trajectory control of the redundant robotic am^ by the use of dedicated controllers to specific joints and specific control commands. Variable structure control is applied to a four degree of freedom robotic manipulator for grinding. The system is modeled using ADAMS and exported to a MATL.Al3 environment where controllers are added and the system is simulated. The results show high potential for applying VSS control without teaching.