摘要
工业机器人具有工作空间大、结构紧凑、灵活性好等优点,但工业机器人机械臂的串联结构形式使其整体刚性存在不足。机器人的末端负载完全由关节处的伺服电机分担,增加了机械臂的驱动功率及能耗。针对上述问题提出一种具有机械手臂的机器人结构,机器人大臂和小臂采用平行四边形框架及对角线驱动的结构形式,利用平行四边形框架平衡外部弯矩作用。仿真结果表明,与工业机器人相比,在仅有外部重力负载作用时大臂的驱动功率可以降低20%~80%,小臂的功率与工业机器人相当;在仅有外部弯矩作用时,无需消耗电机的驱动功率,从原理上降低了机械臂的驱动功率及能耗。此外,对机器人整体刚度进行计算,计算结果表明,此机器人的整体刚度优于工业机器人,有利于提高机器人在搬运、码垛等作业中的负载能力。
Industrial robots are widely used in the fields of handling, stacking and machining due to their advantages of large workspace, compact structure and good flexibility, but the stiffness of the robot is relatively weak due to the series structure. In addition, the external load of the robot is fully shared by servo motors which increase the driving power and energy consumption of the robot arm, especially for the big and small arms. In order to increase the robot stiffness and reduce the driving power of the robot arm, a robot structure with a novel robot arm was presented. A parallelogram structure with diagonal driven was adopted for robot big and small arms. The diagonal electric cylinders driven by ball screws using double nuts with preload to eliminate the reverse backlash, and the anti-backlash method was applied to the rotary base and the robot wrist to eliminate the transmission backlash. By using the parallel quadrilateral frame to balance the external bending moment, the driving power and the energy consumption of the mechanical arm were reduced in principle. The energy consumption of the novel robot and the corresponding industrial robot were compared under the same external load, and the simulation results showed that the driving power of the big arm can be reduced from 20% to 80% compared with the industrial robot and the small arm was equal to the industrial robot when only the external gravity load was applied. Moreover, the power consumption of the driving motor was not required when only external bending moment was applied. Finally, based on the strain energy and Castigliano' s theorem, combining with the robot arms stiffness results using finite element analysis (FEA), the integral robot stiffness was calculated and the results showed that the overall stiffness of the robot was better than that of industrial robots, which made it beneficial to improve the load capacity in the operations of handling, stacking and SO on.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2017年第9期402-410,共9页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51575092)
辽宁重大装备制造协同创新中心项目
关键词
机械手臂
结构设计
性能分析
mechanical arm
structural design
performance analysis