Implementation of trot-to-gallop transition and subsequent gallop on the MIT Cheetah I

Abstract

This paper presents a demonstration of the trot-to-gallop transition and subsequent stable gallop in a robotic quadruped. The MIT Cheetah I, a planar quadruped platform for high-speed running, achieves these tasks with a speed of 3.2 m/s (Froude number of 2.1) on a treadmill. The controller benefits from clues from biological findings and it incorporates (1) a gait pattern modulation that imposes predefined gait patterns with a proprioceptive touchdown feedback, (2) tunable equilibrium-point foot-end trajectories for four limbs that intentionally modulate ground reaction forces, and (3) programmable leg compliance that provides instantaneous reflexes to leg–ground interaction. An inertial measurement unit sensor is integrated with the controller in order to regulate leg angles of attack at touchdown. We reduce the dimension of the control parameters which describe temporal/spatial characteristics of quadruped locomotion, and the values are tuned via dynamic simulation and then experiment. Given a pre-defined virtual leg compliance and a desired angle of attack of legs, the equilibrium-point foot-end trajectories and phase relationships between four legs for stable trot and gallop gaits are found independently. We propose a simple throw-and-catch gait transition strategy which connects two stable limit cycles, the trot and the gallop, by linearly varying control parameters during the transition period. Successful gait transition is achieved in both simulation and experiment. Comprehensive analysis on the characteristics of the MIT Cheetah I experimental trot-to-gallop transition is provided. The phase portraits imply that stable limit cycles are achieved with the proposed controller in both trot and gallop, which enables the trot-to-gallop gait transition at high speed.

The compliant effect of controlled spine on interaction with the ground in quadruped trotting

“…The Bezier curve has the features: two coincident control points lead to zero velocity, and three coincident control points result in zero acceleration. 5,26 In addition, the velocity of initial point of the swing trajectory is proportional to the distance of the P 0 and P 1 . Similarly, the velocity of terminal point is proportional to the distance of the P n –1 and P n .…”

Šešiakojo roboto judėjimo energetinio efektyvumo tyrimas

“…2011), taip pat Masačiusetso technologijos institutui priklausantis robotas gepardas "MIT Cheetah" (D. J. Hyun et. al.…”

A Bio-Inspired Compliance Planning and Implementation Method for Hydraulically Actuated Quadruped Robots with Consideration of Ground Stiffness

“…Recent years have witnessed significant achievements in the research area of legged robots. Versatile high-performance robots, such as BigDog, Spot, and Atlas developed by Boston Dynamics [ 2 ], the MIT cheetah series [ 3 , 4 , 5 , 6 , 7 ], the HyQ [ 8 , 9 ] and the ANYmal [ 10 , 11 ] developed by IIT and ETH Zurich, the Aliengo [ 12 ] from the Unitree Robotics, and the Jueying robots [ 13 , 14 ] developed by the DeepRobotics and Zhejiang University, have brought prospective practical applications. Nevertheless, despite considerable performance improvements in the past 20 years in mechatronics and control, the locomotion efficiency of the state-of-the-art robots lags far behind that of their biological counterparts [ 15 ].…”