In *Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems*, pages 1407--1412, 2003.

doi abstract bibtex

doi abstract bibtex

Humanoid robotics is a new challenging field. To cooperate with human beings, humanoid robots not only have to feature human-like form and structure but, more importantly, they must possess human-like characteristics regarding motion, communication and intelligence. In this paper, we propose an algorithm for solving the inverse kinematics problem associated with the redundant robot arm of the humanoid robot ARMAR. The formulation of the problem is based on the decomposition of the workspace of the arm and on the analytical description of the redundancy of the arm. The solution obtained is characterized by its accuracy and low cost of computation. The algorithm is enhanced in order to generate human-like manipulation motions from object trajectories.

@InProceedings{Asfour2003, Title = {Human-like Motion of a Humanoid Robot Arm Based on a Closed-form Solution of the Inverse Kinematics Problem}, Author = {Asfour, T. and Dillmann, R.}, Booktitle = {Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems}, Year = {2003}, Pages = {1407--1412}, Abstract = {Humanoid robotics is a new challenging field. To cooperate with human beings, humanoid robots not only have to feature human-like form and structure but, more importantly, they must possess human-like characteristics regarding motion, communication and intelligence. In this paper, we propose an algorithm for solving the inverse kinematics problem associated with the redundant robot arm of the humanoid robot ARMAR. The formulation of the problem is based on the decomposition of the workspace of the arm and on the analytical description of the redundancy of the arm. The solution obtained is characterized by its accuracy and low cost of computation. The algorithm is enhanced in order to generate human-like manipulation motions from object trajectories.}, Doi = {10.1109/IROS.2003.1248841}, ISSN = { }, Keywords = {human-like manipulation motions; humanoid robot ARMAR; humanoid robot arm; inverse kinematics problem; object trajectories; redundant robot arm; motion control; position control; redundant manipulators; ECE780}, Review = {Analytical approach. Difficult, only applied to a single arm Robot arms should be similar human arm, kinematically, including redundency. The redundency can be used to avoid joint limits, obstacles and singular conifgurations. One can divide redundancy algorithms into global (requires data on entire Cartesian space to generate globally optimal joint angles trajectories) or local (uses instantaneous position of end effect for local optimization in real time) methods. Various hypothetical cost functions has been suggested for human arm, which has been applied to robotics. They're using a 7 DOF humanoid, described by DH. Some details about the motion limitation/joint workspace of the joints are described. - Shoulder workspace is described as an ellipsoid - The elbow workspace is described as a sphere - This intersection point is difficult to describe. Lots of math - (p3) Describes the elbow vector as a unit vector. - Constrant: position of wrist cannot be further than the physical length of the arm segments So they're breaking down the complicated IK problem into two segments: Shoulder to elbow, and elbow to end-effector They take specific elements from the DH matrix (homogenous transformation blah blah) and reverse (ie calculate the arctan) to find specific angles. So even though we can get a closed analytical solution, there is still an infinite solution. Eqn26 describes a set of parameters that imitates human-like arm motion, based on the desired human arm elevation and yaw angle, given wrist position. From this, the robot joint angles can be determined. It's not perfect, but it's pretty good. Currently, the system ignores dynamics, which is needed to generate realistic velocity.}, Timestamp = {2011.01.07} }

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