High precision feedback control design for dual-actuator systems

Dual-actuator control systems are designed by piggybacking a small secondary actuator onto a primary actuator. Yet the control design for such systems is challenging due to the limited dynamic range of the secondary actuator and its coupling with the primary actuator. In this paper, we propose a new control design approach for dual-actuator systems. We first show that, through a simple coordinate transformation, a dual-actuator system can be separated into two subsystems, one of them controlled only by the primary actuator, which can be designed using conventional methods, and the other one involving tracking control using the secondary actuator. We then devise a switching control strategy for the secondary actuator to achieve high precision control. Two dual-actuator systems are used to demonstrate the use of dual actuators and effectiveness of the new design approach.