Abstract
This thesis presents research work related to the
impedance control of redundant manipulators. The main
goal is to study the effects of redundancy on the dynamic
behaviour of manipulators. Firstly, theoretical
developments related to redundancy, dynamics and
impedance control are presented in general form without
restriction to any particular manipulator. The purpose is
to keep the findings useful for other developments and
continue the research on a wider scale. Later, the Water
Hydraulic MANipulator (WHMAN), which consists of
redundant degrees of freedom, is used for simulations and
experiments. WHMAN is developed at the Department of
Intelligent Hydraulics and Automation at Tampere
University of Technology (IHA/TUT). The purpose of this
manipulator is to provide assistance during the ITER
divertor maintenance and it requires position and force
control during these operations.
The analytical model of WHMAN in the form of state space
equations is used for mathematical analysis and numerical
verification. The verified simulation model is used for
the development and verification of controllers. The
position controllers of the joints are developed using a
linearized model and then fine-tuned using a nonlinear
model and the actual manipulator. The results show that
models of WHMAN can be utilized for control design and
further study.
Both position-based and equivalent force-based
implementations of impedance controller were tested with
the simulation model of WHMAN. The simulation results
showed unstable behaviour of the manipulator for
equivalent force-based implementation. Therefore only the
position-based implementation was used in the
experiments. The results show that, in the absence of
linear mapping between joint-space and operational-space,
the development of equivalent force-based impedance
controller is not straightforward and requires separate
design for the inner-loop force controller.
The theoretical, simulation and experimental results show
that the existence of redundant degrees of freedom can
result in improving the dynamic performance of a
manipulator and thus the impedance regulation
capabilities.
Original language | English |
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Qualification | Doctor Degree |
Awarding Institution |
|
Award date | 4 Nov 2011 |
Place of Publication | Tampere |
Publisher | |
Print ISBNs | 978-952-15-2652-7 |
Electronic ISBNs | 978-952-15-2657-2 |
Publication status | Published - 2011 |
MoE publication type | G5 Doctoral dissertation (article) |
Keywords
- robotic
- impedance control
- water hydraulics