Planning and Execution of Dynamic Whole-Body Locomotion for a Hydraulic Quadruped on Challenging Terrain
This work addresses the problem of efficient and stable locomotion for hydraulic quadrupeds on rough terrain, representing an incremental improvement over prior methods.
The authors tackled dynamic quadrupedal locomotion on challenging terrain by developing a framework that integrates online environment modeling, foothold selection, and trajectory optimization, achieving traversal speeds nearly 6 times faster than their previous work in experimental trials.
We present a framework for dynamic quadrupedal locomotion over challenging terrain, where the choice of appropriate footholds is crucial for the success of the behaviour. We build a model of the environment on-line and on-board using an efficient occupancy grid representation. We use Any-time-Repairing A* (ARA*) to search over a tree of possible actions, choose a rough body path and select the locally-best footholds accordingly. We run a n-step lookahead optimization of the body trajectory using a dynamic stability metric, the Zero Moment Point (ZMP), that generates natural dynamic whole-body motions. A combination of floating-base inverse dynamics and virtual model control accurately executes the desired motions on an actively compliant system. Experimental trials show that this framework allows us to traverse terrains at nearly 6 times the speed of our previous work, evaluated over the same set of trials.