STUDY ON OPTIMAL PATH AND OPERATING TIME FOR DRIVING A MANIPULATOR WITH SAVING ENERGY

节约机械手的耗散能量，对改善火电厂排放的co2气体使地球变暖的环境具有重要意义。因此，本课题研究了垂直铰接机械手PTP运动中能量耗散最小的最优路径和操作时间。粗略估计全局最优路径，使较重的连杆向重力方向加速，向反重力方向减速。该路径作为求解非线性两点边值问题迭代法的起始函数。仿真结果表明，在选择运行时间时，所提出的最优路径比常规路径的耗散能降低1/14 ~ 1/30，达到最优。为了实现仿真结果，改进了由两个直驱电机驱动的双连杆机械手，使第一和第二连杆可以360度以上旋转，并辨识了连杆的惯量和库仑摩擦力等参数。通过数字信号处理器对仿真得到的最优速度函数命令机械手时，对实验结果的路径进行了无误差验证。在伺服驱动器输入处测量耗散能量。实测能量略大于模拟结果的能量。由于三相逆变器实现的伺服驱动器的转换损耗而略有不同。

It is important to save the dissipated energy even of manipulators for improving the environment of the earth which is warmed up by CO_2 gas emitted from thermal power plants. Hence, this project is studied about an optimal path and operating time which minimize the dissipated energy in PTP motions of a vertically articulated manipulators. A globally optimal path is roughly estimated so that the heavier link is accelerated toward gravitational direction and decelerated toward anti-gravitation. This proposed path is used as a starting function of the iteration method solving a non-linear two-point boundary-value problem. The simulation results show that a proposed optimal path can reduce the dissipated energy to 1/14〜1/30 compared with conventional path when the operating time is selected so as to be optimal.In order to implement the simulation results, two-link manipulator driven by two direct drive motors is improved so that the first and second links can be rotated over 360 degree, and the parameters such as inertias and Coulomb friction forces of the links are identified. When the manipulator are commanded to be optimal velocity function obtained by the simulations via a digital signal processor, the path from the experimental result are verified without error. The dissipated energy is measured at input of servo-driver. The measured energy is a little larger than the energy of the simulation result. A little difference is due to the conversion loss of the servo-driver implemented by three-phase inverter.