Adaptive Integral Sliding-Mode Position Control of a Coupled-Phase Linear Variable Reluctance Motor for High-Precision Applications

Key factors limiting the greater use of linear motors are motor cost and complexity of controls. This paper develops an adaptive sliding-mode position control of a coupled-phase linear variable reluctance (LVR) motor for high-precision applications. With several distinct features, the LVR motor can be considered a strong candidate for high-performance linear motion applications due to its simple structure, compactness, and low cost with no permanent magnet. The adaptive position controller based on sliding-mode control is considered because of its simple structure and robustness against uncertain perturbations and external disturbances. The designed controller consists of the following: 1) an inner force control loop based on the sinusoidal flux model for simplicity and computational efficiency and 2) an outer position control based on the adaptive sliding-mode control to enhance the system robustness and to achieve high accuracy for high-precision applications. The LVR motor prototype was constructed for laboratory test, and the controller is implemented on a real-time DSP-based controller card. The comparative experimental results clearly show that the proposed controller is suitable for controlling the LVR motor system for high-accuracy applications and effective for reducing the chattering.