基于遗传算法的串联机械手驱动系统减速比优化

摘要

The driving system of a serial manipulator usually combines an AC servomotor with a precision decelerator,with the latter being used for increasing the driving torque of the driving system and reducing its rotational speed.The reduction ratio of the driving system plays a very important role in accelerating or decelerating the serial manipulator and manipulating its operation speed.Therefore,we use an improved S-shaped speed curve to plan the trajectory of the end-effecter of the serial manipulator,to ensure its continuous acceleration and to reduce its impact while it is moving in a high speed.We propose a method for optimizing the reduction ratio of the driving system,which takes the operation principles of the AC servomotor as constraint conditions and aims at the minimal operation time for completing the planned trajectory.A SCARA robot with 4 degrees of freedom is taken as example.On the basis of the inverse dynamics modeling and trajectory planning,we optimize the reduction ratio of the driving system with the genetic algorithm.The simulation results show that our optimization method is effective,can make full use of the performance of the AC servomotor and consequently helps to reduce the cost of the driving system of the serial manipulator,thus enhancing its overall performance.%串联机械手的驱动系统一般采用交流伺服电动机与精密减速器配套使用的方式。减速器在驱动系统中用于提高驱动力矩、降低输出转速,其减速比直接影响串联机械手的加减速性能和拾放操作速度。基于此,利用改进的S形速度曲线进行轨迹规划,能确保串联机械手加速度的连续,有利于降低机械手高速运动时的冲击。提出一种以平均完成规划的路径轨迹运行时间最短为目标,以交流伺服电动机需满足的运行原则为约束条件,对驱动系统减速比进行优化配置的方法。以4自由度SCARA机器人为例,在逆动力学建模、轨迹规划的基础上,运用遗传算法对最优减速比进行优化。采用该优化方法可以充分发挥交流伺服电动机的性能,从而有利于降低机械手驱动系统的成本,同时提高机械手整体的性能。