7,498 research outputs found
Robust Execution of Contact-Rich Motion Plans by Hybrid Force-Velocity Control
In hybrid force-velocity control, the robot can use velocity control in some
directions to follow a trajectory, while performing force control in other
directions to maintain contacts with the environment regardless of positional
errors. We call this way of executing a trajectory hybrid servoing. We propose
an algorithm to compute hybrid force-velocity control actions for hybrid
servoing. We quantify the robustness of a control action and make trade-offs
between different requirements by formulating the control synthesis as
optimization problems. Our method can efficiently compute the dimensions,
directions and magnitudes of force and velocity controls. We demonstrated by
experiments the effectiveness of our method in several contact-rich
manipulation tasks. Link to the video: https://youtu.be/KtSNmvwOenM.Comment: Proceedings of IEEE International Conference on Robotics and
Automation (ICRA2019
Faster Motion on Cartesian Paths Exploiting Robot Redundancy at the Acceleration Level
The problem of minimizing the transfer time along a given Cartesian path for redundant robots can be approached in two steps, by separating the generation of a joint path associated to the Cartesian path from the exact minimization of motion time under kinematic/dynamic bounds along the obtained parameterized joint path. In this framework, multiple suboptimal solutions can be found, depending on how redundancy is locally resolved in the joint space within the first step. We propose a solution method that works at the acceleration level, by using weighted pseudoinversion, optimizing an inertia-related criterion, and including null-space damping. Several numerical results obtained on different robot systems demonstrate consistently good behaviors and definitely faster motion times in comparison with related methods proposed in the literature. The motion time obtained with our method is reasonably close to the global time-optimal solution along same Cartesian path. Experimental results on a KUKA LWR IV are also reported, showing the tracking control performance on the executed motions
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