Adaptive Iterative Sliding Mode Control: Development, Synthesis, and Application of a Flexure-Joint Biaxial Gantry Stage

In this work, an adaptive iterative sliding mode control method is proposed for multi-axis mechatronic systems. Commonly, the multi-axis mechatronic systems are applied in high-speed and high-precision contouring tasks. For such contouring tasks, the multi-axis coordination is a main issue. As an inevitable challenge, several factors affect the multi-axis coordinate and diminish the contouring performance. Also, some special mechanical structure brings strong coupling to the system, which makes the system identification rather difficult. To solve these problems, this work proposes a learning-based totally model-free control approach for contouring tasks in application to such multi-axis motion stages. With this approach, all the coupling, disturbance, nonlinearity, and other unknown dynamics are regarded as lumped uncertainties in each axis. As a result, these uncertainties can be attenuated and compensated by the proposed controller. To analyze the contouring performance, a case study of a flexure-linked dual-drive H-gantry system is investigated to illustrate the effectiveness of the proposed method.