Optimal Linear Quadratic Gaussian Torque Controller (LQG) for upper limb rehabilitation
With the increasing numbers of degrees of freedom (DOF), modeling and control of the upper-limb robotic devices become significantly challenging. Model uncertainties, parameter inaccuracies, and incompletely known frictional effects also become inevitable, leading to the need for robust control...
| Main Authors: | , , |
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| Format: | Proceeding Paper |
| Language: | English English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/80029/ http://irep.iium.edu.my/80029/1/80029%20Optimal%20Linear%20Quadratic%20Gaussian%20Torque.pdf http://irep.iium.edu.my/80029/2/80029%20Optimal%20Linear%20Quadratic%20Gaussian%20Torque%20SCOPUS.pdf |
| Summary: | With the increasing numbers of degrees of
freedom (DOF), modeling and control of the upper-limb robotic
devices become significantly challenging. Model uncertainties,
parameter inaccuracies, and incompletely known frictional
effects also become inevitable, leading to the need for robust
controller design. This paper presents the design of an optimal
Linear Quadratic Gaussian torque controller (LQG) with
integral action for upper limb rehabilitation robot under the
independent joint control paradigm. The controller is motivated
to ensure optimal robust torque control, to avoid modelling
uncertainties, and to simplify control design process. The
proposed method is demonstrated through a simulation study
and implemented experimentally on two active joints of a 5-DOF
robot prototype. The LQG closed-loop control system responses
to both step and input/output disturbance inputs demonstrated
superior performance of the controller to the traditional PID
controller. The elbow flexion/extension and shoulder
abduction/adduction experiments involving healthy subjects
verified that the controller is able to deliver better performance
within 0.0047Nm and 0.0068 Nm RMS torque tracking errors
for shoulder and elbow respectively. |
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