Change search
ReferencesLink to record
Permanent link

Direct link
Manipulator, Mounting and Integration, and Communication Brick Collection
KTH, School of Electrical Engineering (EES), Automatic Control.
2008 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

The aim of this project is to add manipulation functionality to one of the NASA's Mars rovers through the integration of a robotic arm. The functionality is needed to enable retrieval of deployed communication bricks from the Martian surface. For this, a simple hook end-eector is designed and tested using a controller implemented on a computer.

The manipulator is a ve degree of freedom robotic arm with revolute joints. It is a nonlinear MIMO system but can be approximated to be five highly decoupled linear SISO systems. The manipulator is controlled in joint space, where each joint follows a trajectory. The trajectory is generated as four sequential sub-trajectories, where the manipulator comes to rest at each transition point.

We assume that the Martian surface is free of obstacles and that the manipulator can work in any position on the workspace. We also assume that the position of the hole on the communication brick is known. For controlling the end-eector in joint space, a trajectory-following PD-controller is constructed.

When testing the controller the rst four joints (waist, shoulder, elbow and twist) follow the desired trajectory well. The last joint, wrist, follows the trajectory well for the rst period of time and then start to oscillate around the path curve. The controller was tuned by decreasing Kp value for the wrist joint. The reason for deciding to decrease Kp was to slow the system down and therefore gain an increased stability. Tuning resulted in a better behaving wrist joint controller which follows the desired trajectory in a satisfactory way. Oscillations in wrist have disappeared and the controller works as intended.

We designed and manufactured an end-eector that was within the IRG price range. We established baseline communication with the manipulator, developed a standalone control software and implemented a software for collection of communication bricks. This controller was working properly and fullled the goal set at the beginning of the thesis to design a communication brick collecting manipulator.

Place, publisher, year, edition, pages
2008. , 35 p.
National Category
Control Engineering
URN: urn:nbn:se:kth:diva-105873OAI: diva2:572667
Subject / course
Automatic Control
Educational program
Master of Science in Engineering
Available from: 2012-12-03 Created: 2012-11-28 Last updated: 2012-12-03Bibliographically approved

Open Access in DiVA

fulltext(12865 kB)28 downloads
File information
File name FULLTEXT01.pdfFile size 12865 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Automatic Control
Control Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 28 downloads
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

Total: 30 hits
ReferencesLink to record
Permanent link

Direct link