Robust Adaptive Control of Antagonistic Tendon-Driven Joint in the Presence of Parameter Uncertainties and External Disturbances

Author(s):  
Hongqian Lu ◽  
Xu Zhang ◽  
Xianlin Huang

The design of nonlinear tracking controller for antagonistic tendon-driven joint has garnered considerable attention, whereas many existing control methodologies are impractical in the real-time applications due to complexity of computations. In this work, a robust adaptive control method for controlling antagonistic tendon-driven joint is mainly studied by combining adaptive control with mapping filtered forwarding technique. To enhance the robustness of the closed-loop systems, the true viscous friction coefficients are not needed to be known in our controller design. Typically, to tackle the problem of “explosion of complexity,” filters are introduced to bridge the virtual controls such that the controller is decomposed into several submodules. Mappings and their analytic derivatives are computed by these filters, and the mathematical operations of nonlinearities are greatly simplified. The block diagram of this controller of tendon-driven joint is provided, and controller performances are validated through simulations.

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Gaosheng Luo ◽  
Jiawang Chen ◽  
Linyi Gu

A robust adaptive control method with full-state feedback is proposed based on the fact that the elbow joint of a seven-function hydraulic manipulator with double-screw-pair transmission features the following control characteristics: a strongly nonlinear hydraulic system, parameter uncertainties susceptible to temperature and pressure changes of the external environment, and unknown outer disturbances. Combined with the design method of the back-stepping controller, the asymptotic stability of the control system in the presence of disturbances from uncertain systematic parameters and unknown external disturbances was demonstrated using Lyapunov stability theory. Based on the elbow joint of the seven-function master-slave hydraulic manipulator for the 4500 m Deep-Sea Working System as the research subject, a comparative study was conducted using the control method presented in this paper for unknown external disturbances. Simulations and experiments of different unknown outer disturbances showed that (1) the proposed controller could robustly track the desired reference trajectory with satisfactory dynamic performance and steady accuracy and that (2) the modified parameter adaptive laws could also guarantee that the estimated parameters are bounded.


2020 ◽  
Vol 10 (12) ◽  
pp. 4270
Author(s):  
Jiao Chen ◽  
Jiangyun Wang ◽  
Weihong Wang

Model reference adaptive control (MRAC) schemes are known as an effective method to deal with system uncertainties. High adaptive gains are usually needed in order to achieve fast adaptation. However, this leads to high-frequency oscillation in the control signal and may even make the system unstable. A robust adaptive control architecture was designed in this paper for nonlinear aircraft dynamics facing the challenges of input uncertainty, matched uncertainty, and unmatched uncertainty. By introducing a robust compensator to the MRAC framework, the high-frequency components in the control response were eliminated. The proposed control method was applied to the longitudinal-direction motion control of a nonlinear aircraft system. Flight simulation results demonstrated that the proposed robust adaptive method was able to achieve fast adaptation without high-frequency oscillations, and guaranteed transient performance.


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.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Weiwei Sun ◽  
Guochen Pang ◽  
Pan Wang ◽  
Lianghong Peng

This paper deals with the robust stabilizability andL2disturbance attenuation for a class of time-delay Hamiltonian control systems with uncertainties and external disturbances. Firstly, the robust stability of the given systems is studied, and delay-dependent criteria are established based on the dissipative structural properties of the Hamiltonian systems and the Lyapunov-Krasovskii (L-K) functional approach. Secondly, the problem ofL2disturbance attenuation is considered for the Hamiltonian systems subject to external disturbances. An adaptive control law is designed corresponding to the time-varying delay pattern involved in the systems. It is shown that the closed-loop systems under the feedback control law can guarantee theγ-dissipative inequalities be satisfied. Finally, two numerical examples are provided to illustrate the theoretical developments.


2009 ◽  
Author(s):  
Fulai Liu ◽  
Jikuan Wang ◽  
Ruiyan Du ◽  
Bin Wang

2020 ◽  
Vol 5 (3) ◽  
pp. 135-146
Author(s):  
Ngoc-Duc Nguyen ◽  
Hyeung-Sik Choi ◽  
Han-Sol Jin ◽  
Jiafeng Huang ◽  
Jae-Heon Lee

Hybrid underwater glider (HUG) is an advanced autonomous underwater vehicle with propellers capable of sustainable operations for many months. Under the underwater disturbances and parameter uncertainties, it is difficult that the HUG coordinates with the desired depth in a robust manner. In this study, a robust adaptive control algorithm for the HUG is proposed. In the descend and ascend periods, the pitch control is designed using backstepping technique and direct adaptive control. When the vehicle approaches the target depth, the surge speed control using adaptive control combined with the pitch control is used to keep the vehicle at the desired depth with a constant cruising speed in the presence of the disturbances. The stability of the proposed controller is verified by using the Lyapunov theorem. Finally, the computer simulation using the numerical method is conducted to show the effectiveness of the proposed controller for a hybrid underwater glider system.


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