一种六自由度机械臂的振动特性研究

Vibration characteristics of a 6-DOF manipulator

针对某新型六自由度机械臂末端在工作过程中出现严重抖动的问题,研究了机械臂各运动关节和本体对末端振动特性的影响。构建了机械臂刚柔耦合动力学简化模型,仿真得到了本体在不同工作姿态下的固有频率特性,并结合机械振动测试理论,建立了基于激励+单体+本体+末端振动的路径传递模型;提出了一种机械臂本体固有频率测试和单轴工作模式振动测试相结合的模态试验方法,应用AVANT MI-7008动态频谱分析测试仪,提取了各轴启停时的的振动频率和机械臂本体的一二阶固有频率,获得了机械臂各关节避开共振频率范围。研究结果表明:模态测试获得固有频率和MATLAB仿真结果基本吻合,验证了方案的可行性;为提高机械臂末端定位精度和稳定性提供了一种有效的分析手段。

Aiming at the problem of serious vibration at the end of a new 6-DOF manipulator in the working process,the influence of each movement joint and the body of the manipulator on the vibration characteristics of the end were studied under different working postures.The simplified rigid flexible coupling dynamics model of the manipulator was constructed,the natural frequency characteristics of the body was obtained by simulation.Combined with mechanical vibration testing theory,the path transfer model based on excitation+monomer+ontology+end vibration was constructed,a modal test method combining the natural frequency test of the manipulator body with the vibration test of the single axis working mode was proposed.By using the AVANT MI-7008 dynamic spectrum analyzer,the start stop vibration frequency of each axis and the first and second order natural frequencies of manipulator body was extracted,and joints of the manipulator were avoided the resonance frequency range.The results indicate that the natural frequency test results are basically consistent with the simulation results,which verifies the feasibility of the scheme and provides an effective analysis method for improving the positioning accuracy and stability of the end of the manipulator.