Design, Analysis, and Test of a Novel Self-Sensing Fast Tool Servo

Fast tool servo (FTS) is playing an important role in ultraprecision machining, which however suffers the drawback that the tool/workpiece interaction force as a vital process parameter cannot be monitored. In this article, a novel self-sensing fast tool servo (SFTS) capable of simultaneous control of tool position and measurement of thrust force is developed. The SFTS is especially devised by adopting a novel dual feedback configuration to achieve the decoupled sensing of thrust force, whereas assuring the independent tool moving in feed direction. Analytical model and finite-element model are established to demonstrate the effectiveness of designed SFTS. Apart from the extended capability of traditional FTS in force sensing, theoretical analysis also reveals the proposed SFTS possesses a broad working bandwidth. Experimental verifications are carried out, and the results confirm that the SFTS exhibits nanoscale positioning accuracy, kilohertz-level working bandwidth, and meanwhile millinewton-level force sensing performance. The enabled self-sensing ability and superior performances make this unique SFTS promising and practical for broad applications in ultraprecision machining.