Omnidirectional Monoped Hopper

GOAT (Gear-less Omnidirectional Acceleration Topology)

Daniel Piedrahita

Puneet Singhal

Hadi Salman


Introduction

The GOAT (Gearless Omnidirectional Acceleration Topology) robot is a monoped robot that has 3DOF position control of its foot, as well as high bandwidth proprioceptive force control, meaning that it is capable of both precise foot placement and highly dynamic running gaits. It can achieve high bandwidth, precise, dynamic motion by using three direct-drive electromagnetic actuators connected in a spatial parallel configuration. Direct drive actuation avoids the common problems associated with using gearboxes, including stiction and backlash. These actuators also allow for straightforward implementation of virtual model control on the robot leg, which lets the robot change its stiffness in real time.

goatdiagram.PNG


Virtual Model Control

High-bandwidth virtual model control implemented at 800 hertz in C++ allows the leg to effectively emulate the behavior of a spring-damper system.


Balance Control

3D balance control was achieved through a LQR controller.

3dbalancingGIF.gif


Hopping Control

To achieve successful hopping behavior, a raibert-style controller was developed for the GOAT leg. raiberthopperdiagram


Implementation

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