七轴机械臂避奇异轨迹规划

Singularity avoidance trajectory planning for a seven-axis manipulator

为有效解决机械臂在避奇异轨迹规划时关节角度可能达到关节极限的问题,以思灵机器人公司的七轴机械臂为研究对象,通过微分法建立了机械臂的雅可比矩阵;通过分析可操作度来评估机械臂是否接近奇异态;利用阻尼最小二乘法确定机械臂避奇异的关节角速度;利用零空间下的自运动,限制关节角速度防止其达到运动极限,并提出了新的自运动计算方法。最后,将避奇异的关节角速度与自运动的关节角速度相结合,得到了机械臂的最终关节角速度。通过对比实验和仿真结果,验证了所提计算方法的有效性,有效解决了机械臂在避奇异时关节角度处于极限位置而停止运动的问题。

In order to effectively solve the problem of joint angle reaching the joint limit during singularity avoidance trajectory planning for a manipulator,the Jacobian matrix of the manipulator was established using the differential method,by taking the seven-axis manipulator of Agile Robotics Company as the research object.Whether the manipulator is approaching a singular state was evaluated by analyzing its manipulability measure,and the joint angular velocity of the manipulator to avoid singularity was determined by using the damping least squares method.By utilizing self-motion in null space,the joint angular velocity was restricted to prevent it from reaching the limit of motion,and a new method for calculating self-motion was proposed.Finally,by combining the joint angular velocity of singularity avoidance with the joint angular velocity of self-motion,the final joint angular velocity of the manipulator was obtained.By comparing experiment with simulation results,the effectiveness of the proposed calculation method was verified.The problem that the manipulator stops motion when the joint angle is in the limit position during singularity avoidance is effectively solved.