The fast tool servo (FTS) technology has unique advantages in the machining of complex surfaces such as special-shaped targets and free-form surfaces. In view of the shortcomings in the performance of the existing FTS device, this paper puts forward a novel FTS which uses two piezoelectric ceramics instead of flexure hinges to provide restoring force. Firstly, the feasibility of the double-drive principle is verified theoretically, and the corresponding mechanism is optimized accordingly. Then, the system control hysteresis model is established and identified, and the appropriate control strategy is designed. Finally, the performances of the proposed FTS device are tested, and a typical microstructure is machined based on the device and ultra-precision lathe. The results indicate that the proposed device effectively improves the performance of the FTS system, which is useful for the processing of microstructures and free-form surfaces.

The contact parameters of joint interfaces have a great influence on the dynamic performance of the machine tool, and the dynamic performance determines the machining precision of the machine tool. Therefore, it is important to accurately identify the contact parameters of joint interfaces to improve the machining precision of the machine tool. In this paper, a method of identifying the joint interface stiffness parameters based on a joint simulation in Matlab and Ansys is first proposed, and then stiffness parameters of joint interfaces between the bed and column of the precision grinding machine are identified by applying the method. Finally, the feasibility and high efficiency of the proposed method are proved by comparing the natural frequencies of the simulation and the experiment. In order to further analyze the influence of joint contact parameters on the performance of the joint interfaces, the theoretical model of the normal stiffness of the joint interfaces based on fractal geometry is amended and verified by taking into account the asperity interaction and elastic–plastic deformation. Then, the modified model is extended to a three-dimensional model, which is more in line with the actual situation. Finally, the influencing factors of the joint interface stiffness are analyzed. The conclusions of this paper are of great significance in the dynamic performance analysis and structural design of machine tools.

The characteristic parameters of fixed joint surfaces, such as stiffness and damping, play a dominant role in determining the overall performance of various mechanical structures, especially in high-performance machine tools. However, accurate characterization of these joint parameters remains challenging, due to a lack of direct validation methods. In this study, we consider the deformation of the base caused by the interaction of micro-convex bodies based on the 3D Kogut and Etsion (KE) model, and modify the characteristic parameter model of joint surfaces. Interfacial fractal parameters were determined using the structural function method, which enabled direct experimental validation of the characteristic parameter model. Finally, a comprehensive dynamic performance analysis of the GP300 grinding machine was conducted, and the results revealed that the joint surface changed the various modes of vibration and the corresponding natural frequencies of the machine tool. These findings deepen our understanding of the characteristic parameters of the binding surface and their effects, and have important guiding significance for the performance analysis and design of machine tools.