overconstrained-locomotion

• This is my Undergraduate thesis. This work investegated possible locomotion of an overconstrained leg.
• This work has some initial results of monopod hopping with overconstrained leg; however, it is restricted to a sagittal plane. An independent robot with overconstrained leg must has at least 2 legs. Therefore, future works are expected to solve possible biped/quadruped locomotion.
• Details of this work can be seen in docs\sustechthesis_WangBY_UG21.pdf

Bennett's four-bar linkage

This is an exapmle, or the source of our ispiration, of a Bennett's linkage.

Overconstrained leg

The overconstrained leg is literally half of the four-bar linkage. The first two joints 1 and 2 are chosen to be actuation.

Controller design through templates composition

We first studied a monopod with overconstrained leg. Its frontal plane and sagittal plane view is shown below:

Controlling this monopod jumping in a sagittal plane requires consideration of its foot placement that is not directly underneath the body. $\delta$ here is the angle of projection from leg to YZ plane. The hopping controller is inspired by PennJerboa ¹ and some other works ^{2 3 4}.

Webots experiments

Results

Here are some initial results of the monopod hopping in the sagittal plane.

phase space

sagittal plane trajectories

Some experiments are recorded in videos.

References

[1] The Penn Jerboa: A Platform for Exploring Parallel Composition of Templates

[2] Legged robot that balance

[3] Reactive Planning and Control of Planar Spring–Mass Running on Rough Terrain

[4] Analysis of a Simplified Hopping Robot