含谐波传动关节的机械臂在不同转速下的时频特性

Time-frequency Characteristics of Manipulator with Harmonic Drive Joint under Different Speed

谐波传动关节是机械臂的典型关节。为了研究含谐波传动关节的机械臂在不同转速情况下的时频特性,针对空间机械臂,研制机械臂实验装置和测试系统,测试不同转速下机械臂关节处和末端标志点的振动响应。采用小波变换信号分析方法并借助于机械臂的驱动模型,分析谐波传动关节处的摩擦和运动滞后等非线性因素对不同转速下机械臂振动特性的影响。基于非线性响应面法和非线性规划方法分析了机械臂的最佳运行工况。研究结果表明:小波变换能够较好地表征机械臂在不同转速下关节和末端振动响应的时频特征;随着转速的增大,机械臂关节处和末端标志点的振动能量向低频段集中,振动能量峰值及其对应的频率呈现出局部波动;机械臂末端的振动特性明显弱于关节,关节处的振动频率更为丰富,但关节的振动能量峰值衰减比末端要快;且机械臂处于低速运行工况时可以保持较好的动力学性能。研究结果揭示了含谐波传动关节的机械臂在不同转速下的时频特性,对含谐波关节的机械臂设计及其振动抑制技术水平的提高具有重要意义。

Harmonic drive joints are typical joints of manipulator. In order to study the time-frequency characteristics of the manipulator with harmonic drive joint under different speed, the experiment device and testing system were developed to test the vibration response in the marker points of manipulator joint and end under different speed, taking the space manipulator as the research object. The wavelet transform and the drive model of the manipulator were introduced to analyze the impact of nonlinear factors on the vibration characteristics of the manipulator under different speed, which were caused by friction and movement hysteresis of the harmonic drive joint. Based on the nonlinear response surface method and nonlinear programming method, the optimal operating conditions of the manipulator were analyzed. The results show that the wavelet transform can be used to better represent time-frequency information of the manipulator joint and end under different speed;the vibration energy of the marker points in the manipulator joint and end are concentrated in low frequency, and the vibration energy peak and the corresponding frequency of the manipulator joint and end appear local fluctuation as the speed increases;the oscillation characteristic of the end is significantly weaker than the joint, the vibration frequency of the joint is more abundant, but the decay speed of the joint vibration energy peak is faster than the end;the manipulator can maintain good dynamic performance at low speed. This research reveals the time-frequency characteristics of the manipulator with harmonic drive joint under different speed, which is greatly significant to improve the technique level for the design and vibration suppression of manipulator with harmonic drive joint.