A novel macro-fiber-composite stick-slip actuator with large single-step displacements

Abstract

Precision micro-manipulation tasks demand high-speed motion but low driving frequency for stick-slip actuators to achieve efficient operation and reduce friction wear. This paper presents a novel parasitic-type linear stick-slip actuator with macro fiber composites (MFCs). Unlike conventional piezoelectric actuators, the proposed stick-slip actuator has large single-step displacements and high motion consistency. It can realize high-speed motion under low driving frequency due to the superior properties of MFCs and the dual-drive method with a single driving foot. The actuator is devised based on a multi-beam-compliant driving mechanism, a pair of MFCs, and a slider. Also, an electromechanical dynamic model is proposed. A switching control strategy guarantees high positioning accuracy under large strokes. Finally, an experimental system is built. The single-step displacement can reach 367.7 μm with the dual-drive method. The actuator still has an effective stepping displacement of 63.4 μm even with a load of 2.1 kg. The maximal speed is 131.80 mm/s at a working frequency of 450 Hz. Thus, the actuator can realize mm/s motion with several Hertz driving voltages. Moreover, the maximum forward-reverse deviation only accounts for 1.31 % for a 2504 μm motion range, and the closed-loop motion resolution is 1.970 nm. Experiments verify the effectiveness and performance of the designed MFC stick-slip actuator.