Template-Based and Optimal Control of Dynamic Quadrupedal Gaits

Date

2025-11-26

Author

AKBABA, MUSTAFA

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This work presents a unified, template-based control framework for dynamic quadrupedal locomotion that covers trotting, pronking, and landing. First, we extend the clock-torque actuated spring-loaded inverted pendulum (CT-SLIP) template to 3D. This single template enables walking trot, regular trot, and flying (running) trot. The controller adds a projectile motion model for flight phases and a yaw control that rotates the swing foot plane for better turning stability. A whole-body controller (WBC) is integrated to map template forces to the full robot. The approach is tested extensively in MuJoCo simulation and on the Unitree GO1 robot, showing smooth gait transitions, strong disturbance rejection, and real-world performance. Second, we develop a robust pronking controller by combining the same template dynamics with predictive control. A linear time-varying MPC tracks reference trajectories generated by the template, while a nonlinear MPC (NMPC) plans footsteps using analytical template solutions. The method is implemented in simulation and on hardware. Convergence analysis and disturbance tests confirm stable and adaptable pronking from various initial conditions. Finally, we propose an optimization-based foot placement strategy for safe landing on flat ground. The stance phase uses a spring-damper template. An NMPC minimizes the error between template-predicted moments and actual ground reaction forces at touchdown, while respecting friction constraints. Simulation and hardware experiments demonstrate successful landings at horizontal velocities up to 5 m/s with higher stability than previous methods. Overall, combining simple template models with modern predictive control yields robust, versatile, and high-performance locomotion across multiple gaits and tasks.

Subject Keywords

Template-based control, Legged locomotion, Optimal control, Quadrupedal robotics, Spring loaded inverted pendulum (SLIP)

URI

https://hdl.handle.net/11511/117404

Collections

Graduate School of Natural and Applied Sciences, Thesis