Control strategy for the open loop control of piezo actuators in high frequency machine hammer peening processes

Machine hammer peening is a production technology for the surface finishing of metal parts. A hammer peening tool is utilized to smooth and harden the work piece surface by an incremental micro forming process. Due to the production requirements of a high process force and a working frequency, piezo actuators represent a feasible solution for the process. Achieving high surface quality also requires the implementation of control structures to avoid the resonance frequencies. This paper presents the system prototype of a piezo-based tool for machine hammer peening (""PiezoPeening""). By introducing the system components and identifying relevant parameters, the elements of the control structure are determined and the integration of smart material into the tool is illustrated. Due to the relation between the working frequency, system resonance frequency and surface quality, an analysis by using different working parameters is performed for properly setting the working frequency and actuator pre-load. Based on the results, a control sequence is proposed to deal with different positioning systems.