Abstract: This paper presents a template-based control method for achieving diverse trotting motions in quadrupedal systems, with a focus on smooth transitions between walking trot, regular trot, and flying (running) trot. First, we extend the Clock Torque Actuated Spring-Loaded Inverted Pendulum (CT-SLIP) template to three dimensions, creating a comprehensive control framework. A template-based control strategy is then developed to compute joint torques for stable locomotion, along with a detailed approach for transitioning between gaits. To enable the flight phase in the running trot, a projectile motion model is incorporated into the template. For improved turning, we implement a yaw control method that rotates the swing foot plane to enhance stability, enabling higher turning rates while maintaining steady forward motion and balance. To further enhance locomotion stability and performance, a Whole-Body Controller (WBC) is integrated. The proposed method is implemented and rigorously evaluated in the MuJoCo simulator, with experiments testing gait transitions and disturbance rejection. Additionally, comparative studies assess the impacts of both swing foot plane rotation and the WBC on overall system performance. Furthermore, the approach is validated through real hardware experiments on Unitree GO1 quadrupedal robot, successfully demonstrating smooth gait transitions, stable locomotion, and practical applicability in real-world scenarios.

Key words: Legged locomotion, Template-based control, Gait transition, Trotting')">Legged locomotion, Template-based control, Gait transition, Trotting