3D control of a high-speed quadruped trot

Purpose – Legged vehicles offer several advantages over wheeled vehicles, particularly on broken terrain, but are presently too slow to be considered for many high-speed tasks. This paper presents an effective 3D controller for a high-speed quadruped trot. Design/methodology/approach – To successfully regulate forward velocity and heading, secondary motions such as body pitch and roll must be stabilised. The complicated coupling between pitch and roll motion causes the control effort on one axis to disturb the motion and control effort of the other. Unlike the modular methods in previous research, the algorithm presented here employs a cooperative approach where pitch stability effort is directly accounted for by the roll controller. Findings – When the secondary motions such as pitch and roll are well stabilized, forward velocity and heading can be regulated up to 3 m/s and 208/s, respectively. Research limitations/implications – For many quadrupeds, trotting is usually employed as the precursor to galloping, which is ultimately used at top speeds. Because these two gaits are commonly used together, we expect their control algorithms to share a number of similar components. It is then expected that understanding the quadruped trot will serve as a valuable foundation to understanding the quadruped gallop. Originality/value – This appears to be the first reported regulation of quadruped heading while running at significant speeds.