The Hopping Leg

During our on-going studies of locomotion we have designed and constructed a vertically-constrained hopping robotic leg. The "body" of the robot is a powerful DC motor, and its "leg" and "foot" are a system of tubes and a spring which guarantee smooth and repeatable hopping. The principal design objective was to make the machine track piecewise-constant hopping height commands. This objective is considered the first step toward constructing a four-legged machine that walks and runs. In addition to tracking accuracy, consideration was given to economical operation, in terms of power consumption and computational complexity.

A hopping height controller based on a previously proposed near-inverse algorithm was implemented and its ability to regulate the machine's hopping altitude was demonstrated. The controller assumes a discrete model of the plant dynamics and uses a polynomial approximation of the plant's response to estimate the height of the upcoming hop based on previous hop heights and the applied control input.

Now that a single dimensional model was implemented and studied, we are working on two-dimensional and three-dimensional designs.

Members Involved with the Hopping Leg

One-Dimensional Leg: Andrés Lebaudy, Joe Prosser
Two-Dimensional Leg: Bill Bassill