  This study explores the dynamics of asymmetrical bounding gaits in
quadrupedal robots, focusing on the integration of torso pitching and hip
motion to enhance speed and stability. Traditional control strategies often
enforce a fixed posture, minimizing natural body movements to simplify the
control problem. However, this approach may overlook the inherent dynamical
advantages found in natural locomotion. By considering the robot as two
interconnected segments, we concentrate on stance leg motion while allowing
passive torso oscillation, drawing inspiration from natural dynamics and
underactuated robotics principles. Our control scheme employs Linear Inverted
Pendulum (LIP) and Spring-Loaded Inverted Pendulum (SLIP) models to govern
front and rear leg movements independently. This approach has been validated
through extensive simulations and hardware experiments, demonstrating
successful high-speed locomotion with top speeds nearing 4 m/s and reduced
ground reaction forces, indicating a more efficient gait. Furthermore, unlike
conventional methods, our strategy leverages natural torso oscillations to aid
leg circulation and stride length, aligning robot dynamics more closely with
biological counterparts. Our findings suggest that embracing the natural
dynamics of quadrupedal movement, particularly in asymmetrical gaits like
bounding, can lead to more stable, efficient, and high-speed robotic
locomotion. This investigation lays the groundwork for future studies on
versatile and dynamic quadrupedal gaits and their potential applications in
scenarios demanding rapid and effective locomotion.
