Trajectory and Foothold Optimization using Low-Dimensional Models for Rough Terrain Locomotion
Carlos Mastalli, Michele Focchi, Sylvain Calinon, Jonas Buchli, Ioannis Havoutis, Andreea Radulescu, Darwin G. Caldwell, Claudio Semini
IEEE Conference on Robotics and Automation 2017
Abstract— We present a trajectory optimization framework for legged locomotion on rough terrain. We jointly optimize the Center of Mass (CoM) motion and the foothold locations, while considering terrain conditions. We use a terrain costmap to quantify the desirability of a foothold location. We increase the gait’s adaptability to the terrain by optimizing the step phase duration and modulating the trunk attitude, resulting in motions with guaranteed stability. We show that the combination of parametric models, stochastic-based exploration and receding horizon planning allows us to handle the many local minima associated with different terrain conditions and walking patterns. This combination delivers robust motion plans without the need for warm-starting. Moreover, we use soft-constraints to allow for increased flexibility when searching in the cost landscape of our problem. We showcase the performance of our trajectory optimization framework on multiple terrain conditions and validate our method in realistic simulation scenarios and experimental trials on a hydraulic, torque controlled quadruped robot.
Official paper download link at publisher: coming soon
Pre-prints of all our papers can be found here: http://www.iit.it/hyq (Publications)
The following publications provide the details about the online computation of the terrain costmap and the whole-body controller
C. Mastalli, A. Winkler, I. Havoutis, D. G. Caldwell, C. Semini, On-line and On-board Planning and Perception for Quadrupedal Locomotion, IEEE International Conference on Technologies for Practical Robot Applications (TEPRA), 2015.
M. Focchi, A. del Prete, I. Havoutis, R. Featherstone, D. G. Caldwell, C. Semini, High-slope terrain locomotion for torque-controlled quadruped robots, Autonomous Robots, 259-272, 2017.