Switched control of a SCARA robot with shared actuation resources

Increasing performance demands on industrial motion systems often lead to more expensive hardware components and thus a high bill of materials. Given this trend, it is of interest to find solutions that still can provide good performance, but can be used to reduce the overall bill of materials. In this paper, such a solution is proposed by sharing actuation resources between several actuators and using advanced motion control algorithms for the resulting switched system to meet the performance requirements. Obviously, by the sharing of resources, less hardware components are needed, thereby significantly lowering the bill of materials. We demonstrate this solution on an industrial SCARA robot, where it is proposed to use a single amplifier to serve several actuators, rather than a separate amplifier for each actuator. Based on a switched nonlinear model of the robot, switched PID-type controllers are explored that connect to the industrial control practice. The potential of the proposed approach is shown both in simulations and real experiments on an industrial SCARA robot.