An Efficient Stochastic Constrained Path Planner for Redundant Manipulators

Abstract

This brief proposes a novel stochastic method that exploits the particular kinematics of mechanisms with redundant actuation and a well-known manipulability measure to track the desired end-effector task-space motion in an efficient manner. Whilst closed-form optimal solutions to maximise manipulability along a desired trajectory have been proposed in the literature, the solvers become unfeasible in the presence of obstacles. A manageable alternative to functional motion planning is thus proposed that exploits the inherent characteristics of null-space configurations to construct a generic solution able to improve manipulability along a task-space trajectory in the presence of obstacles. The proposed Stochastic Constrained Optimization (SCO) solution remains close to optimal whilst exhibiting computational tractability, being an attractive proposition for implementation on real robots, as shown with results in challenging simulation scenarios, as well as with a real 7R Sawyer manipulator, during surface conditioning tasks.

Special Issue on Trends and Challenges in Robotic Applications

“…In [29], the authors propose a new stochastic method that efficiently tracks the desired end-effector task-space motions for mechanisms with redundant actuation and is applicable to industrial and collaborative robots. It utilizes manipulability measures and null-space configurations to achieve better manipulability, together with a collision-free trajectory in the task-space, providing a computationally tractable alternative to optimal motion planning, and demonstrated promising results in simulations and real robot scenarios.…”