LTV MPC for Quadruped Locomotion

preprint available here: https://arxiv.org/abs/2212.05154

Authors: Andrew Zheng and Sriram S.K.S Narayanan

This work presents an existing state-of-the-art optimal controller for quadruped locomotion. The robot dynamics is represented using a single rigid body (SRB) model. A linear time-varying model predictive controller (LTV MPC) is proposed by using linearization schemes. Simulation results show that the LTV MPC can execute various gaits, such as trot and crawl, and is capable of tracking desired reference trajectories even under unknown external disturbances. The LTV MPC is implemented as a quadratic program using $qpOASES$ through the $CasADi$ interface at 50 Hz. The proposed MPC can reach up to 1 m/s top speed with an acceleration of 0.5 m/s$^2$ executing a trot gait.

Requirements

Basic: MATLAB and MATLAB optimization toolbox Optional: CasADi

Run

Navigate to main directory and run Convex_MPC.m Set 'use_Casadi'

• 0: quadprog w/ MATLAB optimization
• 1: qpoases w/ CasADi

References

• Di Carlo, Jared, et al. "Dynamic locomotion in the mit cheetah 3 through convex model-predictive control." 2018 IEEE/RSJ international conference on intelligent robots and systems (IROS). IEEE, 2018.
• Ding, Yanran, et al. "Representation-free model predictive control for dynamic motions in quadrupeds." IEEE Transactions on Robotics 37.4 (2021): 1154-1171.