Simultaneous Contact and Motion Planning

Simultaneous Contact and Motion Planning

Bringing the gap between what legged robots can do requires to carefully plan motion and foothold planning over challenging terrains. Motion and foothold planning requires to consider the robot’s dynamics and the terrain model in a suitable numerical optimization formulation. However, mathematically speaking, this problem is hard to solve due to contact discontinuities, nonlinear, high-dimensional and under-actuated dynamics.

To this end, we have proposed different numerical optimization formulations: nonlinear [1], stochastic [2,3] and mixed-integer convex [4] optimizations. In [1], we proposed a hierarchical numerical optimization which helps to plan jumping maneuvers and its contact event. We have studied non-convex terrain model which is used to plan motions and footholds through a stochastic optimization [2,3]. We use a cart-table with flywheel model and the robot stability is guaranteed by keeping the centroidal moment pivot inside the support polygon [3]. Finally, we have proposed to plan different quadrupedal gaits, and their foothold locations, by formulating both through integer variables [4].

[1] non linear optimization

[2] stochastic optimization

 

[3] stochastic optimization

[4] mixed-integer convex optimization

Selected publications:

[1] Mastalli et al. Hierarchical planning of dynamics movements without scheduled contact sequences.
[2] Mastalli et al. Motion planning for quadrupedal locomotion: coupled planning, terrain mapping and whole-body control.
[3] Mastalli et al. Trajectory and foothold optimization using low-dimensional models for rough terrain locomotion.
[4] Aceituno-Cabezas et al. Simultaneous contact, gait and motion planning for robust multi-legged locomotion via mixed-integer convex optimization.

Contact:Carlos Mastalli