We present a method that finds locomanipulation plans that perform simultaneous locomotion and manipulation of objects for a desired endeffector trajectory. Key to our approach is to consider an injective locomotion constraint manifold that defines the locomotion scheme of the robot and then using this constraint manifold to search for admissible manipulation trajectories. The problem is formulated as a weightedA* graph search whose planner output is a sequence of contact transitions and a path progression trajectory to construct the wholebody kinodynamic locomanipulation plan. We also provide a method for computing, visualizing, and learning the locomanipulability region, which is used to efficiently evaluate the edge transition feasibility during the graph search. Numerical simulations are performed with the NASA Valkyrie robot platform that utilizes a dynamic locomotion approach, called the divergentcomponentofmotion (DCM), on two example locomanipulation scenarios.
Stampede: A DiscreteOptimization Method for Solving PathwiseInverse Kinematics
We present a discreteoptimization technique for finding feasible robot arm trajectories that pass through provided 6DOF Cartesianspace endeffector paths with high accuracy, a problem called pathwiseinverse kinematics. The output from our method consists of a path function of jointangles that best follows the provided endeffector path function, given some definition of ``best''. Our method, called Stampede, casts the robot motion translation problem as a discretespace graphsearch problem where the nodes in the graph are individually solved for using nonlinear optimization; framing the problem in such a way gives rise to a wellstructured graph that affords an effective best path calculation using an efficient dynamicprogramming algorithm. We present techniques for sampling configuration space, such as diversity sampling and adaptive sampling, to construct the searchspace in the graph. Through an evaluation, we show that our approach performs well in finding smooth, feasible, collisionfree robot motions that match the input endeffector trace with very high accuracy, while alternative approaches, such as a stateoftheart perframe inverse kinematics solver and a global nonlinear trajectoryoptimization approach, performed unfavorably.
 Award ID(s):
 1830242
 Publication Date:
 NSFPAR ID:
 10104781
 Journal Name:
 2019 International Conference on Robotics and Automation (ICRA)
 Sponsoring Org:
 National Science Foundation
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