Bogie rover black

DARK ROVER ROCKER-BOGIE OPTIMIZATION DESIGN
Thomas Brooks Graham Gold Nick Sertic

Self Sponsored

Applied Science 479 Engineering Physics The University of British Columbia

Project Number 1076 January 18, 2011

Executive Summary
There were three goals for this project: to build an inexpensive test track, to design a rocker-bogie suspension system, and to quantify changes in energyusage based on the rover’s geometry. We successfully built a test track capable of repeatable tests, an easily modifiable rocker-bogie system, and found some very favourable results through testing. We tested the rover by running it along the test track and monitoring the instantaneous current and voltage values of each drive motor. By repeating the run several times at a fixed rover configuration wewere able to get average values for the run. We then integrated this data and produced a value of energy consumption per configuration. This is the main metric within our report. The most optimal configuration that we tested in terms of minimal energy consumption was with a 90 degree primary angle, back hole mounting, standard slot length. Further tests were done about this point and we also foundthat energy consumption decreases if the primary angle between the rocker and bogie is increased by tens of degrees, and the slot position is shortened. Overall, the optimal configuration used 15% less energy than the worst configuration we tested, and 6.4% less energy than the next least energetic setup. Moving the slot from the standard mounting position to the shortened one reduced the energyconsumption by 2.5%. These results indicate that our tesing setup produces useful results which can be used to guide further design of the rocker-bogie system such that energy consumption is minimized. After conducting this project and analyzing the results we have defined four main recommendations for future work. 1. Further testing to be done with a six wheeled rover chassis. 2. Include more realisticand difficult obstacles on the testing tracks. 3. Use higher quality motors and wheels on the rover. 4. Design the next rover with three driving wheels, instead of two.

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Contents
1 Introduction 1.1 Background and Motivation 1.2 Project Objectives . . . . . 1.3 Project Scope . . . . . . . . 1.4 Report Organization . . . . 5 5 7 8 8 10 10 10 11 13 14 15 15 17 18 18 19 21 25 26 26 26 27 28 3132 38

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2 Discussion 2.1 Methods and Testing Protocol . . . . . . . . . . . . . . . . . . . . 2.1.1 Test Track Fabrication . . . . . . . . . . . . . . . . . . . .2.1.2 Rover Design . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.3 Data Acquisition . . . . . . . . . . . . . . . . . . . . . . . 2.2 Experimental Equipment . . . . . . . . . . . . . . . . . . . . . . . 2.3 Data Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.1 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.2 Calculating Energy . . . . . . . . . . .. . . . . . . . . . . 2.4 Discussion of Results . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.1 General Trends for Front and Back Motor Power Consumption 2.4.2 Energy Consumptions for Different Configurations . . . . . 2.4.3 Overall Rankings of Tested Configurations . . . . . . . . . 3 Conclusion 4 Project Deliverables 4.1 List of Deliverables . . . . . . . . . . . . . . . . . . . . . . . . .. 4.2 Financial Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Ongoing Commitments . . . . . . . . . . . . . . . . . . . . . . . . 5 Recommendations A References B MATLAB Code C Solidworks Drawings

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List of Figures
1.1 1.2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Example of a Rocker-Bogie System . . . . . . . . . . . . . . . . . Test Surface used by Miller and Lee . . . . ....