Differential-Evolution-Based Parameter Identification Method for a Redundant Hybrid Robot Using POE Model

作者：Wu, Yong-Bo^*; Wu, Hua-Peng; Handroos, Heikki

来源：Journal of the Chinese Society of Mechanical Engineers, 2013, 34(3): 195-202.

• Identification
• Error Model
• Differential Evolution
• Hybrid Robot
• Product of Exponential (POE)

This paper presents a kinematic calibration method for a redundant serial-parallel robot to improve its end-effector positioning accuracy. The studied robot is composed of a kinematically redundant serial mechanism with four degree-of-freedom (DOF) and a hexapod parallel manipulator with full six degree-of-freedom in a three-dimensional space. The serial mechanism is designed to enlarge the robot's workspace whereas the parallel manipulator is used to improve the robot end-effector accuracy. The robot will be adopted for the assembly of vacuum vessel of the international thermonuclear experimental reactor (ITER) by carrying out various tasks, such as welding, machining, non-destructive testing, measuring the gap between two adjacent sectors and transporting a premade splice plate to match the measured gap. Based on the product of exponentials (POE) formula, an error model involving 60 kinematic parameters is derived, which accounts for the kinematic errors originated from the manufacturing and assembly processes. Due to its hybrid serial-parallel kinematic structures and a large number of identification parameters in a high nonlinear error model, the traditional iterative least-square algorithms cannot be used to identify the error parameters.

• 出版日期2013-6