Feasibility evaluation method for trajectory of redundant manipulators based on null-space

In order to deal with the problem that the traditional methods are unable to online determine the feasibility of the tip's trajectory of redundant manipulators under joint limit and collision constraints, a method based on the description of null space was provided to online determine the feasibility of the tip's trajectory of S-R-S redundant manipulators. Firstly, a method for efficiently computing the null-space under joint limits and a modified collision detection method were developed to compute the null-space of redundant manipulators in real time. If the null-space of the specified tip pose was empty, the tip pose would never achieve for the limitation of the joint limit or collision. Then, based on this idea, a evaluate method was developed for determining the feasibility of the desired trajectory of the S-R-S redundant manipulator. The method doesn't need to pre-compute and build a database for the workspace of redundant manipulators as the traditional methods, and can determine the feasibility of the tip's trajectory under multi-constraints in real time. Finally, the effectiveness and real-time of the proposed method were demonstrated by the experiments on a redundant manipulator. © 2019, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.