Triaxial Fast Tool Servo Using Hybrid Electromagnetic-Piezoelectric Actuation for Diamond Turning

A high-performance triaxial fast tool servo (FTS) with the hybrid electromagnetic-piezoelectric actuation and the hybrid parallel-serial-kinematic structure is reported. Featuring the balanced and uniform actuation, in this article, a novel axis-symmetric linearized reluctance actuator is proposed to generate the planar motion in parallel, and the piezoactuated vertical motion is then serially carried by the planar motion within a limited space. Verified by the finite-element analysis, a two-stage design strategy is developed to optimally determine the multiphysical system parameters for the triaxial FTS, assisted by an analytical model of the electromagnetic circuit as well as the mechanical mechanism. As for the trajectory tracking, the loop-shaping tuned PID controller with a feedforward compensator is employed for each axis, and a damping controller is additionally designed for the planar motion. Finally, both open-loop and closed-loop performance of the prototype are carefully demonstrated.

Automated summary

This article reports a high-performance triaxial fast tool servo (FTS) that utilizes hybrid electromagnetic-piezoelectric actuation and a hybrid parallel-serial-kinematic structure. The novel axis-symmetric linearized reluctance actuator is proposed for generating planar motion in parallel, and the piezoactuated vertical motion is carried out serially within a limited space. A two-stage design strategy is developed using finite-element analysis to optimize the system parameters for the triaxial FTS. Trajectory tracking is achieved through loop-shaping tuned PID controllers and a damping controller for planar motion.