Non-spherical ball-socket joint design for Delta-type robots

作者：Yang Eileen Chih Ying^*; Yen Ming Hsien; Chou Ming Ti; Huang Zhen Jia; Chen Sin Kai

来源：Mechatronics, 2017, 45: 14-24.

DOI：10.1016/j.mechatronics.2017.05.003

• Loading deflection
• Link flexibility
• Joint clearance
• Non-spherical ball-socket joint

Delta-type robots are commonly used for positioning purposes in medical surgery. In such applications, the loading position accuracy of the end effector is of critical importance. However, the positioning accuracy is determined by the loading deflection, which depends in turn on the link flexibility and joint clearance within the system. Importantly, the loading deflection is posture/position dependent. This characteristic greatly complicates the task of improving the positioning accuracy using traditional compensation control methods. Accordingly, the present study proposes a non-spherical ball-socket joint design to improve the loading stiffness of the robot over the entire workspace. An analytical model is derived to quantify the loading deflection as a function of the link flexibility and joint clearance. The experimental results show that the non-spherical ball-socket joint design reduces the total variation in the loading deflection of the end effector by up to 81.04% compared to that of a traditional robot with spherical ball-socket joints when performing positioning over the entire workspace at the assigned height.

• 出版日期2017-8