Robust Adaptive Control of the Nonlinearly Parameterized Human Shank Dynamics for Electrical Stimulation Applications

Author(s):  
Ruzhou Yang ◽  
Marcio de Queiroz

In this paper, we introduce two robust adaptive controllers for the human shank motion tracking problem that is inherent in neuromuscular electrical stimulation (NMES) systems. The control laws adaptively compensate for the unknown parameters that appear nonlinearly in the musculoskeletal dynamics while providing robustness to additive disturbance torques. The adaptive schemes exploit the Lipschitzian and/or the concave/convex parameterizations of the model functions. The resulting control laws are continuous and guarantee practical tracking for the shank angular position. The performance of the two robust adaptive controllers is demonstrated via simulations.

2010 ◽  
Vol 6 (2) ◽  
pp. 145-149
Author(s):  
Ibrahim Jasim

This paper presents a new strategy for controlling induction motors with unknown parameters. Using a simple linearized model of induction motors, we design robust adaptive controllers and unknown parameters update laws. The control design and parameters estimators are proved to have global stable performance against sudden load variations. All closed loop signals are guaranteed to be bounded. Simulations are performed to show the efficacy of the suggested scheme


2004 ◽  
Vol 126 (1) ◽  
pp. 229-235 ◽  
Author(s):  
Dong H. Kim ◽  
Hua O. Wang ◽  
Hai-Won Yang

This paper describes a systematic procedure to design robust adaptive controllers for a class of nonlinear systems with unknown functions of unknown bounds based on backstepping and sliding mode techniques. These unknown functions can be unmodeled system nonlinearities, uncertainties and disturbances with unknown bounds. Both state feedback and output feedback designs are addressed. In the design procedure, the upper bounds of the unknown functions are estimated using an adaptation strategy, and the estimates are used to design stabilizing functions and control inputs based on the backstepping design methodology. The proposed controllers guarantee that the tracking errors converge to a residual set close to zero exponentially for both state feedback and output feedback designs, while maintaining the boundedness of all other variables.


Author(s):  
JIANPING CAI ◽  
LUJUAN SHEN ◽  
FUZHEN WU

We consider a class of uncertain non-linear systems preceded by unknown backlash-like hysteresis, which is modelled by a differential equation. We propose a new state feedback robust adaptive control scheme using a backstepping technique and properties of the differential equation. In this control scheme, we construct a new continuous function to design an estimator to estimate the unknown constant parameters and the unknown bound of a ‘disturbance-like’ term. The transient performance of the output tracking error can be guaranteed by the introduction of pre-estimates of the unknown parameters in our controller together with update laws. We do not require bounds on the ‘disturbance-like’ term or unknown system parameters in this scheme. The global stability of the closed-loop system can be proved.


2012 ◽  
Vol 263-266 ◽  
pp. 817-821 ◽  
Author(s):  
Yi Mei Chen ◽  
Shao Ru Chen

The problem of robust adaptive stabilization of a class of multi-input nonlinear systems with unknown parameters and structure has been considered. By employing the direct adaptive method to a general nonlinear adaptive system, a robust adaptive controller is designed to complete the global asymptotically stability of the system states. Some simulations are provided to illustrate the effectiveness of the proposed method.


2001 ◽  
Vol 11 (04) ◽  
pp. 1149-1158 ◽  
Author(s):  
YIGUANG HONG ◽  
HUASHU QIN ◽  
GUNARONG CHEN

This letter addresses the problem of robust adaptive control for synchronization of continuous-time coupled chaotic systems, which may be subjected to disturbances. A general model is studied via two different approaches, using either state feedback or measured output feedback controls. Adaptive controllers are designed, in which a sliding mode structure is employed to increase the robustness of the closed-loop systems. When only output variables are measurable for synchronization, the adaptive controllers are designed by incorporating with a filter and using the so-called σ-modification technique. Several numerical examples are presented to show the effectiveness of the proposed chaos synchronization methods.


2016 ◽  
Vol 13 (03) ◽  
pp. 1650010 ◽  
Author(s):  
Zhengcai Cao ◽  
Longjie Yin ◽  
Yili Fu ◽  
Jian S. Dai

A significant amount of work has been reported in the area of vision-based stabilization of wheeled robots during the last decade. However, almost all the contributions have not considered the actuator dynamics in the controller design. Considering the unknown parameters of the robot kinematics and dynamics incorporating the actuator dynamics, this paper presents a vision-based robust adaptive controller for the stabilization of a wheeled humanoid robot by using the adaptive backstepping approach. For the controller design, the idea of backstepping is used and the adaptive control technique is applied to treat all parametric uncertainties. Moreover, to attenuate the effect of the external disturbances on control performance, smooth robust compensators are employed. The stability of the proposed control system is analyzed by using Lyapunov theory. Finally, simulation results are given to verify the effectiveness of the proposed controller.


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