Foothold selection for quadruped robots based on feasible ground reaction force sets

Davulcu, Furkan
Legged robots mainly control their speed and posture only at the stance phase, when their feet touch the ground, by producing desired forces on the body using ground reaction forces. However, the selection of footholds affects the forces that can be put on the body during the stance phase. This thesis presents a new foothold selection framework that selects footholds considering the friction cone, motor limits, and leg geometry to help the stance controllers control the speed and posture of the robot more effectively. We evaluate our framework in the scenario of coming to a stop from a diverse set of initial conditions on a planar quadrupedal robot in simulation and compare it with the widely used Raibert's heuristic for foothold selection. Our experiments show that the planar quadruped robot converges to the desired state faster and spends less energy while the motors spend less time in their torque limits using our method. Furthermore, our method makes the quadrupeds more robust against unexpected disturbances by selecting footholds that give more flexibility to stance controllers in terms of force output capability.


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Citation Formats
F. Davulcu, “Foothold selection for quadruped robots based on feasible ground reaction force sets,” M.S. - Master of Science, Middle East Technical University, 2022.