INTELLIGENT PASSIVE CONTROL FOR LOWER LIMB REHABILITATION SYSTEM

2013 ◽  
Vol 37 (3) ◽  
pp. 1023-1033 ◽  
Author(s):  
Ming-Shium Hsieh ◽  
Chin-Sheng Chen ◽  
Kuan-Sheng Chien

This paper proposes the design and control of continuous passive motion (CPM) machine based on constraint-induced movement therapy (CIMT). First, the dynamic model of the CPM machine is derived for further controller design by the principal of virtual work. Then, an intelligent sliding-mode control (ISMC) system which involved recurrent Hermite neural network (RHNN) estimator to estimate the unknown external disturbance and uncertainty is proposed to track the angular position and velocity of the CPM machine.

2013 ◽  
Vol 284-287 ◽  
pp. 2249-2254 ◽  
Author(s):  
Ming Shium Hsieh ◽  
Chin Sheng Chen ◽  
Kuan Sheng Chien

In this paper, we present the design and control of continuous passive motion (CPM) machine based on Constraint-Induced Movement Therapy (CIMT) for a patient who needs knee rehabilitation. First, the dynamic model of the CPM machine is derived by the principal of virtual work in dynamics. Then, an intelligent sliding-mode control (ISMC) system which involved recurrent Chebyshev neural network (RCNN) estimator to estimate the unknown external disturbance and uncertainty online is proposed to track the angular position and velocity of the CPM machine. Furthermore, we prove that the proposed ISMC system is asymptotically stable via Lyapunov theory. Finally, the experimental results are illustrated to demonstrate that the ISMC system can effectively reduce chattering phenomenon and precisely track reference trajectory of the CPM machine.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Wenxing Fu ◽  
Binbin Yan ◽  
Xiaofei Chang ◽  
Jie Yan

Hypersonic technology plays an important role in prompt global strike. Because the flight dynamics of a hypersonic vehicle is nonlinear, uncertain, and highly coupled, the controller design is challenging, especially to design its guidance and control law during the attack of a maneuvering target. In this paper, the sliding mode control (SMC) method is used to develop the guidance law from which the desired flight path angle is derived. With the desired information as control command, the adaptive neural control in discrete time is investigated ingeniously for the longitudinal dynamics of the hypersonic missile. The proposed guidance and control laws are validated by simulation of a hypersonic missile against a maneuvering target. It is demonstrated that the scheme has good robustness and high accuracy to attack a maneuvering target in the presence of external disturbance and missile model uncertainty.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Ruiping Xu ◽  
Zhen Liu ◽  
Cunchen Gao ◽  
Huimin Xiao

The problem of integral sliding mode control (ISMC) with passivity is investigated for a class of uncertain neutral systems with time-varying delay (NTSTD) and external disturbance. The system states are unavailable. An ISMC strategy is proposed based on the state estimate. By employing a novel sliding functional, a new sufficient criterion of robust asymptotic stability and passivity for both the error system and the sliding mode (SM) dynamic system is derived via linear matrix inequality (LMI) technique. Then, a SM controller is synthesized to guarantee the reachability of the sliding surface predefined in the state estimate space. Finally, a numerical example shows the feasibility and superiority of the obtained result.


2011 ◽  
Vol 22 (2) ◽  
pp. 137-147 ◽  
Author(s):  
Jian-Ping Jiang ◽  
Dong-Xu Li

This study deals with decentralized robust vibration control of a smart composite panel with parameter uncertainties. The composite panel with four collocated piezoelectric actuators and velocity sensors is modeled using finite element method, and then the size of the model is reduced in the state space using Modal Hankel Singular Value. The parameter uncertainties presented by natural frequencies and modal damping ratios are considered in controller design process. To suppress the vibration induced by external disturbance, a decentralized robust H∞ controller is developed using linear matrix inequality techniques. Numerical simulation for the smart panel is performed in order to investigate the effectiveness of decentralized vibration control (DVC). When the system is subjected to an initial displacement field or distributed white noise disturbance, numerical results show that the DVC system is very effective. Although there are 20% parameter uncertainties for modal frequencies, damping ratio, and control input, the decentralized controller can effectively suppress the vibration excited by the external disturbance. Furthermore, the decentralized controller composed of four three-order systems can be practically implemented well.


1997 ◽  
Vol 122 (1) ◽  
pp. 108-113 ◽  
Author(s):  
Shyh-Leh Chen ◽  
Steven W. Shaw ◽  
Hassan K. Khalil ◽  
Armin W. Troesch

The dynamics and control of a strongly nonlinear 3-DOF model for ship motion are investigated. The model describes the roll, sway, and heave motions occurring in a vertical plane when the vessel is subjected to beam seas. The ship is installed with active antiroll tanks as a means of preventing large amplitude roll motions. A robust state feedback controller for the pumps is designed that can handle model uncertainties, which arise primarily from unknown hydrodynamic loads. The approach for the controller design is a combination of sliding mode control and composite control for singularly perturbed systems, with the help of the backstepping technique. It is shown that this design can effectively control roll motions of large amplitude, including capsize prevention. Numerical simulation results for an existing fishing vessel, the twice-capsized Patti-B, are used to verify the analysis. [S0022-0434(00)02701-5]


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jinwei Sun ◽  
Jingyu Cong ◽  
Weihua Zhao ◽  
Yonghui Zhang

As the deviation error will accumulate during the data acquisition and transcoding process of an active suspension system, this paper presents a sliding-mode-based quantized feedback control method. The aim of the controller is to improve the vertical performance of vehicles in the presence of external interferences. A 7-DOF suspension model with nonlinear springs and actuator dynamics is built for the control purpose. Firstly, a static quantizer on the uplink channel and a dynamic quantizer on the downlink channel are considered in the sliding mode controller to reduce the cumulative error and suppress the sprung mass motions. Secondly, an event trigger mechanism is introduced in the controller design process to reduce energy consumption and operation frequency of the actuator. The overall stability of the designed controller is proved by the Lyapunov functions. Finally, numerical simulations are carried out to evaluate the efficacy of the proposed controller. Different quantitative and trigger conditions are discussed, and the random road excitation is considered as the external disturbance input. The results of the control method indicate that the designed controller can improve the riding comfort with little loss of handling stability compared with the passive system. In addition, the trigger mechanism can improve the working efficiency of actuators effectively.


2019 ◽  
Vol 93 ◽  
pp. 03002
Author(s):  
Plamena Zlateva

Biogas production by anaerobic digestion with addition of acetate is considered. Sliding mode control for regulation of the biogas flow rate using the addition of acetate as a control action is proposed. The control design is carried out with direct use of nonlinear model and expert knowledge. Chattering phenomena are avoided by realizing the sliding mode with respect to the control input derivative. The state variables, external disturbance, process output and control input are varied in the known intervals. The performance of the designed sliding mode control is investigated by varying the process set point and the uncertain process parameter, which reflecting the influence of the external disturbance. The excellent performance of presented control is proved through simulation investigations in MATLAB using Simulink.


Author(s):  
Zhuojun Luo ◽  
Mengling Wu ◽  
Jianyong Zuo

Instead of using knowledge-based controllers, which need a lot of experience and experimental data to form a reliable knowledge base, a model-based controller is proposed in this article based on a sliding mode control method to control the brake cylinder pressures of an electropneumatic brake on subway trains. The complicated structure of the electropneumatic brake is simplified, and an order-reduced nonlinear model of the plant is built. An equivalently continuous technique based on pulse width modulation is used to deal with the discontinuity of the plant model, which is derived from the discontinuous nature of On/Off valves. The nonlinear sliding mode controller is designed for air charging and discharging periods, respectively. Measures such as continuous approximation and control dead zone are introduced into the controller to improve control performance. This article concerns mainly about the theoretical part of the whole research. Plant parameter identification and controller tests are performed in a sequel article.


2020 ◽  
Vol 23 (1) ◽  
pp. 45-50
Author(s):  
Hazem Ali ◽  
Azhar Jabbar Abdulridha ◽  
Rawaa Khaleel ◽  
Kareem Kareem A. Hussein

In this work, the design procedure of a hybrid robust controller for crane system is presented. The proposed hybrid controller combines the linear quadratic regulator (LQR) properties with the sliding mode control (SMC) to obtain an optimal and robust LQR/SMC controller. The crane system which is represented by pendulum and cart is used to verify the effectiveness of the proposed controller. The crane system is considered one of the highly nonlinear and uncertain systems in addition to the under-actuating properties. The parameters of the proposed LQR/SMC are selected using Particle Swarm Optimization (PSO) method. The results show that the proposed LQR/SMC controller can achieve a better performance if only SMC controller is used. The robustness of the proposed controller is examined by considering a  variation in system parameters with applying an external disturbance input. Finally, the superiority of the proposed LQR/SMC controller over the SMC controller is shown in this work.


2019 ◽  
Vol 9 (9) ◽  
pp. 1753 ◽  
Author(s):  
Ramamurthy Jeyasenthil ◽  
Seung-Bok Choi

This paper proposes a systematic feedback controller design methodology for multi-input multi-output (MIMO) uncertain systems using the quantitative feedback theory (QFT). To achieve this goal, the model matching problem was considered and the inversion feedforward controller was designed to improve control performance while reducing the demand on feedback control alone. The proposed method is formulated based on the concept of equivalent disturbance attenuation (EDA) approach in which the uncertain system problem is converted into an external disturbance rejection problem based on a nominal system. This proposed approach exhibiting non-sequential design method result in the suboptimal solution showing design simplicity and computational efficiency compared to the existing method. In order to validate the effectiveness of the proposed control methodology, the MIMO magnetic levitation system as adopted and control performances such as time response were presented in both time and frequency domains.


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