Všechny publikace

Caterpillar Heuristic for Gait-Free Planning With Multi-Legged Robot

  • DOI: 10.1109/LRA.2023.3293749
  • Odkaz: https://doi.org/10.1109/LRA.2023.3293749
  • Pracoviště: Katedra počítačů, Centrum umělé inteligence
  • Anotace:
    In this letter, we address path planning for the quasi-static locomotion of a multi-legged walking robot on terrains with limited available footholds, such as passing a water stream over rocks. The task is to find a feasible sequence of steps to navigate the robot in environments where precise foot placement and order of the leg movements are necessary for successful traversal. A finite set of the considered footholds forms a state-space search domain, where states are defined by pairing the robot legs with footholds. The actions represent the connectivity of submanifolds of the robot configuration space approximating the robot's kinematic constraints indicating possible steps in a given stance. We propose a novel heuristic that significantly reduces the number of expanded states in the A* planner by avoiding local minima exhibited by commonly used heuristics. The computational requirements are nearly an order of magnitude lower than for the existing contact-driven solutions reported in the literature for similarly formulated planning problems. The viability of the proposed approach is further supported by an experimental deployment.

Motion Planning for Multi-legged Robots using Levenberg-Marquardt Optimization with Bezier Parametrization

  • Autoři: Ing. David Valouch, prof. Ing. Jan Faigl, Ph.D.,
  • Publikace: Proceedings of 11th European Conference on Mobile Robots. Brighton: Institute of Electrical and Electronics Engineers, 2023. p. 344-348. ISSN 2639-7919. ISBN 979-8-3503-0704-7.
  • Rok: 2023
  • DOI: 10.1109/ECMR59166.2023.10256284
  • Odkaz: https://doi.org/10.1109/ECMR59166.2023.10256284
  • Pracoviště: Katedra počítačů, Centrum umělé inteligence
  • Anotace:
    This paper presents a novel formulation of motion planning for multi-legged walking robots. In the proposed method, a single-step motion is formulated as a nonlinear equation problem (NLE): including kinematic, stability, and collision constraints. For the given start and goal configurations, the robot's path is parametrized as Bezier curve in the configuration space. The resulting NLE is solved using Levenberg-Marquardt optimization implemented using a sparse matrix solver. We propose handling the trigonometric kinematic constraints with the polynomial path parametrization. A relaxation of the constraint is used while guaranteeing a desired tolerance along the planned path. Although the proposed method does not explicitly optimize any criterion, it produces high-quality paths. The method is deployed in transforming a sequence of discrete configurations produced by a step sequence planner into a valid path for a multi-legged walking robot in challenging planning scenarios where a regular locomotion gait cannot be used because of sparse footholds.

Gait-free Planning for Hexapod Walking Robot

  • DOI: 10.1109/ECMR50962.2021.9568834
  • Odkaz: https://doi.org/10.1109/ECMR50962.2021.9568834
  • Pracoviště: Katedra počítačů, Centrum umělé inteligence
  • Anotace:
    This paper presents a gait-free motion planning approach for quasi-static walking of hexapod walking robots on terrains with limited available footholds. The proposed approach avoids using a prescribed gait pattern allowing an arbitrary sequence of leg swings. Furthermore, it is allowed that some legs do not need to be placed on the terrain for an extended duration. The proposed method is based on a decomposition of the motion planning into: (i) finding a candidate sequence of stances and intermediate configurations representing plausible steps using a graph-search; and (ii) connecting the intermediate configurations by feasible paths satisfying the motion constraints of the walking robot. The individual one-step paths are determined using a Bézier curve-based parametrization that seems to be sufficient for the relatively simple paths of a single step, and the low-capacity parametrization yields natural-looking motion.

Za stránku zodpovídá: Ing. Mgr. Radovan Suk