Experiments in Balance With a 2D One-Legged Hopping Machine

TLDR

Balance is crucial for legged mobility and may enable versatile vehicles; the one‑legged hopping machine used here emphasizes balance, and prior modeling of similar devices by Raibert informs its design. The study constructs a 2D one‑legged hopping machine to investigate balance’s role in legged locomotion and to develop suitable control strategies. The machine’s locomotion is controlled by a three‑part scheme comprising vertical height, horizontal velocity, and angular attitude regulation. The simple three‑part control scheme enabled the machine to hop in place, run at a set speed, move between locations, and clear obstacles.

Abstract

The ability to balance is important to the mobility obtained by legged creatures found in nature, and may someday lead to versatile legged vehicles. In order to study the role of balance in legged locomotion and to develop appropriate control strategies, a 2D hopping machine was constructed for experimentation. The machine has one leg on which it hops and runs, making balance a prime consideration. Control of the machine’s locomotion was decomposed into three separate parts: a vertical height control part, a horizontal velocity part, and an angular attitude control part. Experiments showed that the three part control scheme, while very simple to implement, was powerful enough to permit the machine to hop in place, to run at a desired rate, to translate from place to place, and to leap over obstacles. Results from modeling and computer simulation of a similar one-legged device are described by Raibert [10].