Change search
ReferencesLink to record
Permanent link

Direct link
Software control of an eight wheeled-legged hybrid robot
2010 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Space robots such as rovers have typically used wheeled mobility systems such as the rocker-bogie suspension system. However, NASA’s ATHLETE robot featuring a hybrid wheeled-legged mobility system signifies a shift in direction. Legged and hybrid mobility systems improve on wheeled systems in their enhanced ability to move effectively on rough terrain. One class of legged robots that have been strongly researched for space applications are frame-walking systems. These robots typically have legs with sliding prismatic joints to provide a degree of freedom in the vertical direction. The present thesis work is targeted to a hybrid eight wheeled-legged robot called the Zero-Carrier. The robot is designed for transportation of disabled and elderly people, and has legs with sliding prismatic joints to allow stair-climbing ability. The aim of the thesis was to implement the upper-level control software for the next version of the robot. The role of the software is to detect obstacles using on-board sensors and control actuators to move the robot to autonomously overcome the obstacles. To allow implementation, testing and demonstration of the software a simulation platform was developed using OpenGL for 3D visualisation. The described control software improves on previous versions by providing intelligent control of individual legs using state machines, while centrally coordinating movements to guarantee stability. This results in a wider range of obstacles that can be overcome. Advanced features including center of gravity control, smooth movement and level movement on slopes are also addressed to improve passenger comfort and safety. Results for a set of simulation test cases are presented which demonstrate the implemented control software’s ability to overcome various obstacle situations. In the context of space robotics, strong similarities were demonstrated between Zero-Carrier and various researched space robots. The research work therefore provides a relevant examination of the complexities encountered in performing the autonomous control of such a complex machine.

Place, publisher, year, edition, pages
Keyword [en]
Technology, Space robotics, hybrid mobility system, 3D-simulation, control, software, stair climbing.
Keyword [sv]
URN: urn:nbn:se:ltu:diva-53498ISRN: LTU-PB-EX--10/068--SELocal ID: a8250134-7a91-4c7c-80a7-9da248ed0626OAI: diva2:1026872
Subject / course
Student thesis, at least 30 credits
Educational program
Space Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

Open Access in DiVA

fulltext(2176 kB)0 downloads
File information
File name FULLTEXT01.pdfFile size 2176 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

ReferencesLink to record
Permanent link

Direct link