We propose an adaptive stabilization solution for a linear second-order system with unknown parameters, where only the position and the sign of the constant associated with the control input are known. The control str...
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We propose an adaptive stabilization solution for a linear second-order system with unknown parameters, where only the position and the sign of the constant associated with the control input are known. The control strategy consists in proposing a filter system with its whole state available and having the same structure as the uncertain system. Then, based on the Immersion & Invariance approach, and the Model Reference method, we design an adaptive controller to stabilize the filter system. Finally, using the backstepping approach, we stabilize the original uncertain system. We carry out the convergence analysis using the traditional Lyapunov method, in conjunction with the Barbalat's Lemma. The obtained control strategy is simple and easy to implement. We assess the effectiveness of our adaptive control strategy through numerical simulations.
Humans perform a wide range of skillful and dexterous motion by adjusting the dynamic characteristics of their musculoskeletal system during motion. This capability is based on the non-linear characteristics of the mu...
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ISBN:
(纸本)9781424466757
Humans perform a wide range of skillful and dexterous motion by adjusting the dynamic characteristics of their musculoskeletal system during motion. This capability is based on the non-linear characteristics of the muscles and the motor control architecture that can control motion and exerted force independently. Mechanical impedance (i.e. stiffness, viscosity and inertia) constitutes the most solid characteristic for describing the dynamic behavior of human movements. This paper presents a method for estimating upper limb impedance characteristics in the three-dimensional (3D) space, covering a wide range of the arm workspace. While subjects maintained postures, a seven-degrees-of-freedom (7-DoFs) robot arm was used to produce small displacements of subjects' hands along the three Cartesian axes. The end-point dynamic behavior was modeled using a linear second-order system and the impedance characteristics in the 3D space were identified using the measured forces and motion profiles. Experimental results were confirmed with two subjects.
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