基于多轴同步控制的微尺度双向加载实验系统

Aimed at the currently insufficient experimental condition for the research on yielding and hardening behavior in microforming of ultrathin sheets, a micro-scaled biaxial loading test system was presented, which can achieve complex loading paths. The system is characterized with four independent driving axes in hardware, coupled with separated upper computer and lower computer in software structure. The digital image correlation (DIC) method is adopted to capture deformation strain in the biaxial tension process. The control model of permanent magnet synchronous motor (PMSM) was first established, and the control parameters of speed closed loop were identified. The control accuracy of single-axis position closed-loop is significantly improved by using the nonlinear PID control method, and the four-axis synchronous control under diverse displacement/load ratios is realized on the basis of virtual axis method. The biaxial loading experiment reveals that the system satisfies the requirements of displacement synchronization error within 0.02 mm and load synchronization error within 0.05 kN. The developed system can thus be used for experimental research on yielding and hardening behavior of ultrathin sheet.