Design of novel adaptive magnetic adhesion mechanism for climbing robots in ferric structures ...

157 Pages·2017·8.31 MB·English

by  Francisco Ochoa

Design of novel adaptive magnetic adhesion mechanism for
climbing robots in ferric structures

By:

Francisco Ochoa Cardenas

A thesis submitted in partial fulfilment of the requirements for the degree of
Doctor of Philosophy

The University of Sheffield
Faculty of Engendering
Department of Automatic Control and Systems Engineering

November 2016
ii
iii
iv
Abstract
The work presented in this thesis proposes a novel adaptive magnetic
adhesion mechanism that can be implemented in most locomotion
mechanisms employed in climbing robots for ferric structures. This novel
mechanism has the capability to switch OFF and ON its magnetic adhesion
with minimal power consumption, and remain at either state after the
excitation is removed. Furthermore, the proposed adhesion mechanism has
the ability to adapt the strength of the adhesive force to a desired magnitude.
These capabilities make the proposed adhesion mechanism a potential
solution in the field of wall climbing robots.
The novel contributions of the proposed mechanism include the
switching of the adhesive force, selectivity of the adhesive force magnitude;
determination of the parameters that have an impact in the final adhesive
force. Finally, a final prototype is constructed with customised components
and it is subject to a set of simulations and experiments to validate its
performance.

iii
iv
Acknowledgments
Firstly, I would like to express my deepest gratitude to my supervisor,
Prof. Tony J. Dodd, for all his support, guidance through the PhD and
specially for his patience.
All my gratitude to the people that encouraged me on pursuing the PhD
and that always were present.
• My wife, whose support, patience and encouragement where vital for
reaching the end.
• My daughter and son, which are the motor that push me go further and
never give up.
• My parents, whose care, support and guidance in life have driven me to
reach the unimaginable.
• My aunts Cuca and Pina Ochoa, and uncle Luis Ochoa, who set the
basis, along with my parents, that allowed me be where I am, and more
important to be who I am
Last but not least, I would like to thank my two Mexicans sponsors,
CONACyT and SEP (under Becas Complemento SEP grant), for the great
opportunity to going abroad to study and contribute the future of my
country.

v
vi
Contents
1.1. Motivation ........................................................................................................ 2
1.2. Problem definition ......................................................................................... 4
1.3. Aims and objectives ....................................................................................... 4
1.4. Contributions ...................................................................................................5
1.5. Thesis outline .................................................................................................. 6
2.1. Classification of the unmanned vehicles ................................................ 10
2.2. Wall climbing mobile robots ...................................................................... 14
2.2.1. Locomotion mechanisms ............................................................... 18
2.2.2. Adhesion mechanisms .................................................................... 21
2.3. WCMR for inspection of ferric structures ............................................. 26
2.3.1. Electro-permanent magnets ......................................................... 28
2.4. Concluding remarks ..................................................................................... 31
3.1. Theory.............................................................................................................. 33
vii
3.1.1. Important concepts ........................................................................ 34
3.2. Working principles ...................................................................................... 39
3.2.1. OFF and ON configurations .......................................................... 40
3.2.2. Variable magnetic adhesive force ............................................... 43
3.2.3. Characteristics of the EPMs ......................................................... 44
3.3. Validation of the electro-permanent magnet concept ....................... 45
3.3.1. Basic configuration and components of the EPM .................. 46
3.3.2. Equipment and experimental setup .......................................... 48
3.3.3. Simulation and experimental results: basic OFF and
ON configurations ........................................................................... 54
3.3.4. Switching between states and variable magnetic
adhesive force ................................................................................... 58
3.4. Concluding remarks .................................................................................... 64
4.1. Locomotion mechanism selection .......................................................... 66
4.1.1. Selection of the locomotion mechanism and EPMAM
integration ......................................................................................... 70
4.2. EPMAM Implementation in the wheeled locomotion
mechanism ..................................................................................................... 73
4.2.1. Preliminary simulations of the wheeled EPMAM
design ...................................................................................................77
4.3. Validation of the proposed wheeled locomotion mechanism
with EPMAM .................................................................................................. 80
4.3.1. OFF and ON states validation ....................................................... 81
4.3.2. Validation of the OFF-ON and ON-OFF switching, and
variable magnetic adhesion .......................................................... 83
4.4. Concluding remarks .................................................................................... 90
5.1. Influence of the individual design components in the final
adhesive force ................................................................................................ 94
5.1.1. Steel keepers ..................................................................................... 95
5.1.2. Enamelled wire gauge..................................................................... 97
5.1.3. Gap between EPM device and adhesion surface ..................... 98
5.2. Configuration of the EPMAM into the wheel ...................................... 101
5.2.1. Rotating EPMAM ............................................................................ 101
viii