Commanding a Whole-Arm Manipulation Grasp Configuration With One Click: Interaction Concept and Analytic IK Method

Robotic assistance in nursing is becoming increasingly important due to labor shortage and novel capabilities in hard- and software. In nursing, patients often need to be manipulated which requires force distribution beyond the scope of traditional end effectors. This can be solved with whole arm manipulation (WAM). Unfortunately, commanding WAM configurations for grasping patients is very complex, as many contact points need to be achieved, and all 6 or 7 degrees of freedom have to be defined. In this paper, a novel interaction concept and according to inverse kinematic solvers based on a local elliptic approximation are proposed, which allows commanding a WAM holding grasp with one click on a point cloud. It is shown how the local elliptic model is used for formulating a very fast analytic multi-contact inverse kinematic solver. Two alternative solvers are derived by extending the BioIK method and by utilizing the popular sequential quadratic programming approach. Experiments show the efficiency of the analytic method and the robustness of the local elliptic model relative to perceptual perturbations.