双臂并联煤矸石分拣机器人及其轨迹规划研究

Research on dual-arm parallel coal gangue sorting robot and its trajectory planning

目前的煤矸石自动分拣系统大多采用串联机械臂,只能分拣出粒度较小的矸石,且分拣速度较慢,分拣效果不理想。针对该问题,设计了一种双臂并联煤矸石分拣机器人。该机器人采用推动而非抓取的分拣方式,能够针对粒度为300~600 mm的矸石进行分拣,且大大降低了机械臂的力矩需求,提高了分拣速度。为了避免频繁启停给电动机造成刚性冲击,延长电动机使用寿命,在关节空间下分别采用抛物线过渡的插值函数、三次多项式及五次多项式插值函数进行轨迹规划,仿真和对比分析结果表明,采用五次多项式插值函数进行轨迹规划时,角加速度曲线过渡平滑,不仅能满足机器人轨迹起始点和终止点的角度、角速度约束,还能满足其角加速度约束,使分拣机器人的运动轨迹更加平稳。实验结果表明:对于粒度为300~600 mm的煤矸石,双臂并联煤矸石分拣机器人矸石识别率和分拣率分别为91.14%和86.29%,分拣准确率和稳定性较高;完成单次完整的分拣动作只需1.2 s,与人工分拣相比大大缩短了分拣周期;通过在关节空间的轨迹规划,降低了分拣过程中电动机受到的刚性冲击,可保证机器人长时间稳定工作。

At present,the automatic sorting system of gangue mostly adopts series mechanical arm,which can only sort out the gangue with small particle size.The separation speed is slow and the separation effect is not ideal.In view of this problem,a kind of dual-arm parallel coal gangue sorting robot was designed.The robot adopts the sorting mode of pushing rather than grasping,which can sort the gangue with the particle size of 300-600 mm,and greatly reduce the torque demand of the manipulator and improve the sorting speed.In order to avoid rigid impact caused by frequent start-up and stop and prolong the service life of the motor,parabola interpolation function,cubic polynomial interpolation function and quintic polynomial interpolation function are respectively used for trajectory planning in joint space.Simulation and comparative analysis results show that the angular acceleration curve transition is smooth when using quintic polynomial interpolation function for trajectory planning,the angle and angular velocity constraints of the starting and ending points of the robot trajectory are satisfied,and the angular acceleration constraint is also satisfied,so that the motion trajectory of the sorting robot is more stable.The experimental results show that for the coal gangue with particle size of 300-600 mm,the recognition rate and sorting rate of dual-arm parallel coal gangue sorting robot are 91.14%and 86.29%respectively,with high sorting accuracy and stability;it only takes 1.2 s to complete a single complete sorting operation,which greatly shortens the sorting cycle compared with manual sorting;through joint space trajectory planning,the rigid impact of the motor in the sorting process is reduced,which can ensure the system stable work for a long time.