电液伺服双轴疲劳试验力控制系统及其幅值相位控制算法的研究

Investigation on a Biaxial Electro-hydraulic Servo Control System for Fatigue Testing and Amplitude and Phase Control Algorithm

由于汽车排气管在实际运行环境中受到复杂交变载荷,单轴的疲劳试验不能准确预测试件的疲劳寿命。双轴的协同加载能更好地模拟实际工况,但需要对两个轴力传感器输出信号的幅值和相位差进行精确控制。因此,针对排气管双轴动态加载的需求,研发一种力控制的电液伺服式双轴疲劳试验加载装置,并设计基于PXI总线结构和多DSP并行处理技术的多轴伺服控制器,基于伺服闭环和外环驱动谱修正相结合的控制算法,实现了双通道正弦波的幅值相位控制。为验证算法的性能,两通道参考信号均采用频率为10 Hz,幅值为2. 363 k N的正弦波,并且相位差为90°,对排气管进行双轴疲劳试验。试验结果表明:该双轴力加载系统能精确地跟踪参考信号的幅值和相位差。

Since exhaust pipe suffers comlicated alternating load in the actual environment,the single-axial fatigue test can not accurately predict the fatigue life.The biaxial cooperative loading can better simulate the actual working condition,but the amplitude and phase difference of output signals of the two axial force sensors need to be precisely controlled.An electro-hydrualic biaxial fatigue test rig was developed for dynamic load of exhaust pipe.Furthermore,a multi-axis controller based on PXI bus and multi-DSP parallel precessing was designed.The two-channel amplitude and phase control of sinusoidal wave were realized by using the algorithm of iteratively correcting the driving signal spectrum.To verify the performance of the algorithm,the biaxial fatigue test was carried out on the exhaust pipe when reference signals are both 10 Hz sinusoidal waves with an amplitude of 2.363 kN and the phase difference of the two-channel is 90°.The experimental results show that the developed biaxial loading system performs good for amplitude and phase difference.