Electrical and Computer Engineering ETDs

Publication Date

Fall 12-21-2016

Abstract

This dissertation describes the development of a control algorithm that transitions a robotic linkage system between stabilized states producing responsive locomotion. The developed algorithm is demonstrated using a simple robotic construction consisting of a few links with actuation and sensing at each joint. Numerical and experimental validation is presented. In this algorithm, transitioning excitations, called rhythms, are formulated using terminal state control solutions. Rhythms are constrained to be low order parameterized functions allowing for the optimal control problem to be replaced by a parametric optimization problem with a limited set of easily solved unknowns. This algorithm is developed and demonstrated using a simply linkage system consisting of only two links joined at a knee, called a two-link. The two-link can exist in a number of different configurations of various dynamic orders. The highest order configuration occurs when the two viii link is in flight. Transition from a higher order to a lower order configuration occurs when a link impacts or parts from the ground. A “no rebound” condition at the point of impact is assumed. An increase in order occurs as the result of a link parting from the ground such as would occur in the presence of control actuation. Rhythms can be cascaded together using state transition logic to produce locomotion. Sequential two-link rhythms to stand, crouch, and continuous hop produce responsive locomotion. Uncertainty reduction and controllability is not continuous but intermittent, adding to the complexity of the control problem. The derived algorithm was validated by hardware implementation. Solid models of two-link parts were generated in SolidWorks and printed using an Ultimaker 2+ 3D printer. Printed solids were assembled with mechanical and electrical substructure to produce instrumentality. Control was hierarchical. High level communications were transmitted via an I2C interface from a Raspberry Pi 3 model B microcomputer to A/D and D/A converters while low level communication within the two link occurred between mid-range microchip PIC processors and motor drivers. Rhythms that allowed the two-link to stand, crouch, hop and lie down were programmed in Raspberry Pi software.

Keywords

two-link rhythms control robotics hybrid

Document Type

Dissertation

Language

English

Degree Name

Electrical Engineering

Level of Degree

Doctoral

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Prof. Chaouki Abdallah

Second Committee Member

Prof. Rafael Fierro

Third Committee Member

Prof. Meeko Oishi

Third Advisor

Prof. Chaouki Abdallah

Fourth Committee Member

Prof. Frank Lewis

Comments

Please let me know if further revisions are requested at the below address.

I do not have a signed dissertation approval page although one was produced by the ECE department.

The approval page is now p.i.

Download

Share

COinS