title: A behavior-based inverse kinematics algorithm to predict arm prehension postures for computer-aided ergonomic evaluation.
abstract: In this paper, the computational problem of inverse kinematics of arm prehension movements was investigated. How motions of each joint involved in arm movements can be used to control the end-effector (hand) position and orientation was first examined. It is shown that the inverse kinematics problem due to the kinematic redundancy in joint space is ill-posed only at the control of hand orientation but not at the control of hand position. Based upon this analysis, a previously proposed inverse kinematics algorithm (Wang et Verriest, 1998a) to predict arm reach postures was extended to a seven-DOF arm model to predict arm prehension postures using a separate control of hand position and orientation. The algorithm can be either in rule-based form or by optimization through appropriate choice of weight coefficients. Compared to the algebraic inverse kinematics algorithm, the proposed algorithm can handle the non-linearity of joint limits in a straightforward way. In addition, no matrix inverse calculation is needed, thus avoiding the stability and convergence problems often occurring near a singularity of the Jacobian. Since an end-effector motion-oriented method is used to describe joint movements, observed behaviors of arm movements can be easily implemented in the algorithm. The proposed algorithm provides a general frame for arm postural control and can be used as an efficient postural manipulation tool for computer-aided ergonomic evaluation.
mesh_terms: D000328:Adult; D000465:Algorithms; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D004551:Elbow Joint / Q000502:physiology; D006804:Ergonomics; D005069:Evaluation Studies as Topic; D005544:Forecasting; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009068:Movement; D011187:Posture; D015203:Reproducibility of Results; D012785:Shoulder Joint / Q000502:physiology; D014955:Wrist Joint / Q000502:physiology