A Power Series Based Inverse-Kinematics Solution of Humanoid Robot Finger with Coupled Joints

摘要

Inverse-kinematics is an emphasis and difficulty in the design and application of the humanoid robot hand with coupled joints because of nonlinearity induced by trigonometric transcendental function. In this paper, a power series based inverse-kinematics algorithm is presented, by which the transcendental equation including trigonometric function can be converted into an algebraic equation. An approximate solution is derived first by means of power series expansions; with 1D linear interpolation for errors compensating, the final solution with small error can then be achieved. For robot with linearly coupled joints, the algorithms based on power series expanded to quadratic and quartic terms are used to calculate the accurate joint angles. For robot with nonlinearly coupled joints, the specific procedures are proposed to select appropriate transmission ratio. Simulation and experimental results demonstrate effectiveness of the proposed inverse kinematics method.