蛇形机械臂的机构设计与关节驱动分析

Mechanism design and joint drive analysis of snake-arm manipulators

考虑到蛇形机械臂相比于传统六轴机械臂在运动灵活性和避障性能等方面具有明显优势,选择蛇形机械臂进行了研究。为了使其适应各类非结构化环境,给出了一种基于绳索驱动的设计方法,并用等效转轴描述方法建立了蛇形臂运动学模型,进行了静态逐模块受力分析。机械臂各模块之间串联连接,采用绳索驱动方式实现机械臂全驱动。在静态逐模块受力分析中,考虑了绳索所受摩擦力的影响,并引入了一种优化函数,分析了关节驱动绳索的牵引力大小,从而对绳索驱动位移伸长量进行补偿。同时,建立了基于CAN总线的闭环控制系统,提高了关节姿态准确度。最后,在ADAMS仿真环境中进行运动学仿真,通过与理想位姿的对比验证了位移补偿方法的可行性,并通过样机试验验证了控制系统的有效性。

Considering that compared to traditional six-axis manipulators,a snake-arm has the obvious advantages in terms of movement flexibility and obstacle avoidance,a study on snake-like manipulator is conducted. In order to make a snake-like arm adapt to various types of unstructured environments,a new design method for snake-like arms based on wire driven is given,a kinematic model for snake-like arms is established by using the method for description of equivalent rotating shaft,and a static force module analysis is performed. The modules are connected in series. Fully driven of the snake-arm is based on the rope-driven approach. In the static force module analysis,the influence of the rope friction force is considered. An optimization function is introduced to analyze the traction force of the joint drive rope,so as to compensate the elongation of the rope displacement. Further,a closed-loop control system based on CAN bus is established to improve the accuracy of joint pose. Finally,the kinematic simulation is carried out in ADAMS simulation environment. The feasibility of the displacement compensation method is verified by comparing with the snake-arm＇s ideal pose,and the effectiveness of the control system is verified by the prototype test.