面向实时运动学标定的机械臂轨迹规划

Trajectory Planning of Robot Arm for Real-Time Kinematic Calibration

为解决机械臂标定效率低的问题,针对机械臂实时标定中的作业-标定共用轨迹的规划方法进行了研究。首先,选择立体视觉作为测量方式,减少对机械臂末端的物理约束;然后,以作业轨迹和靶标可视性为约束条件,采用DETMAX算法选出最优测量构型作为轨迹中间点,并分析了中间点聚类数量与轨迹极值间的关系,作为确定轨迹数量的依据;最后,在关节空间下仿真分析了新方法所得轨迹特征。研究结果表明,匀速运动段与静止段间相连的角度和角速度轨迹均具有良好平滑性,角加速度连续且无跳动;角速度和角加速度轨迹极值远低于实际对应的指标极限;各关节在中间点的角度准确且停留时间充足。因此新方法能够满足机械臂在不停工前提下开展实时标定的要求。

For the low efficiency of robot arm calibration,the planning method of work-calibration co-trajectory in robot arm real-time calibration was investigated.Firstly,stereovision was selected to relax the physical constraints on the end-effector.Then,taking the work trajectory and the visibility of marker as constraints,the DETMAX algorithm was used to select the optimal measurement configuration as the via points of the co-trajectory.And then the relationship between the clustering of via points and the extremum of each trajectory was analyzed to determine the number of co-trajectories.Finally,the new trajectory was simulated and analyzed in joint space.The results show that the angle and angular velocity trajectories connected between the uniform motion segment and the stationary segment are smooth,and the angular acceleration is continuous with no jumping.The extreme values of angular velocity and angular acceleration trajectory are much lower than the limits of actual corresponding indicators.The angles of each joint at the via points are accurate and the stationary times are sufficient.Therefore,the new method meets the requirements of real-time calibration of robot arm without suspension of work.