Modified Sky-Hook Control of a Semi-Active Suspension System Using H∞ Robust Control Theory

2009 ◽  
Author(s):  
Mohammad Saber Fallah ◽  
Rama Bhat ◽  
Wen-Fang Xie
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Controller Design ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Output Feedback Control ◽  
Suspension System ◽  
Linear Matrix ◽  
Control Force ◽  
The Stability

The main focus of the present paper is on the design of a modified sky-hook control of a semi-active Macpherson suspension system by means of H∞ Output Feedback Control (OFC) theory. To this end, a new dynamic model, incorporating the kinematics of the suspension system, is used for the controller design. The combination of a Linear Matrix Inequality (LMI) solver and Genetic Algorithm (GA) is adopted to regulate the static output feedback control gain so that the stability conditions are fulfilled and control objectives are achieved. Meanwhile, a three-dimensional kinematic model of the system is incorporated to investigate the influence of the control force variation on the steering, handling and stability of the vehicle. A geometric relation of the vehicle roll center is employed to study one more extra aspect of the comfort and stability of the vehicle. The results show that the proposed controller improves the kinematic and dynamic performances of the suspension well compared with those of the passive system. Moreover, it is concluded that a superior stability of the vehicle during the cornering can be achieved by adjusting the height of the vehicle roll center passively so that the stability of the vehicle is improved while the forward motion specifications can be modified by an appropriate suspension control design.

scholarly journals TCSC Controller Design Based on Output Feedback Control with Linear Matrix Inequality

2000 ◽  
Vol 33 (5) ◽  
pp. 185-190
Author(s):  
Masachika Ishimaru ◽  
Goro Shirai ◽  
Satoru Niioka ◽  
Ryuichi Yokoyama
Keyword(s):  
Feedback Control ◽  
Linear Matrix Inequality ◽  
Output Feedback ◽  
Controller Design ◽  
Output Feedback Control ◽  
Linear Matrix ◽  
Matrix Inequality

scholarly journals Static Output Feedback Control for Discrete-Time Switched Systems via Improved Path-Following Method

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jian Chen ◽  
Chong Lin
Keyword(s):  
Feedback Control ◽  
Discrete Time ◽  
Output Feedback ◽  
Switched Systems ◽  
Controller Design ◽  
Output Feedback Control ◽  
Path Following ◽  
Static Output Feedback ◽  
Static Output Feedback Control ◽  
Static Output

This paper focuses on the problems of static output feedback control andH∞controller design for discrete-time switched systems. Based on piecewise quadratic Lyapunov functions and a new linearization method, new sufficient conditions for system stability andH∞controller design are obtained. Then, an improved path-following algorithm is built to solve the problems. Finally, the merits and effectiveness of the proposed method are shown by two numerical examples.

On Selection of Control Parameters for H∞ Output Feedback

2005 ◽  
Author(s):  
Chang-Ching Chang ◽  
Chi-Chang Lin
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Output Feedback ◽  
Delay Time ◽  
Output Feedback Control ◽  
Feedback Gain ◽  
Control Force ◽  
Control Parameters ◽  
Structural Responses ◽  
Control Forces

In this paper, an H∞ direct output feedback control algorithm through minimizing the entropy, a performance index measuring the tradeoff between H∞ optimality and H2 optimality, is employed to design the control system in reducing structural responses due to dynamic loads such as earthquakes. The control forces are obtained from the multiplication of direct output measurements by a pre-calculated time-invariant feedback gain matrix. To achieve optimal control performance, the strategy to select both control parameters γ and α is extensively investigated. The decrease of γ or increase of α results in better control effectiveness, but larger control force requirement. For a single degree-of-freedom (SDOF) damped structure, exact solutions of output feedback gains and control parameters are derived. It can be proved analytically that the LQR control is a special case of the proposed H∞ control. Direct velocity feedback control is effective in reducing structural responses with very small number of sensors and controllers compared with the DOFs of the structure. In active control of a real structure, control force execution time delay cannot be avoided. Relatively small delay time not only can render the control ineffective, but also may cause system instability. In this study, explicit formulas to calculate maximum allowable delay time and critical control parameters are derived for the design of a stable control system. Some solutions are also proposed to increase the maximum allowable delay time.

H ∞ Control for Continuous-Time Switched Linear Systems

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Grace S. Deaecto ◽  
José C. Geromel
Keyword(s):  
Feedback Control ◽  
Linear Systems ◽  
Output Feedback ◽  
Continuous Time ◽  
Design Problem ◽  
State Feedback ◽  
Output Feedback Control ◽  
Control Design ◽  
Linear Matrix ◽  
Switched Linear Systems

This paper deals with the output feedback H∞ control design problem for continuous-time switched linear systems. More specifically, the main goal is to design a switching rule together with a dynamic full order linear controller to satisfy a prespecified H∞ level defined by the L2 gain from the input to the output signal. Initially, the state feedback version of this problem is solved in order to put in evidence the main difficulties we have to face toward the solution of the output feedback control design problem. The results reported in this paper are based on the so called Lyapunov–Metzler inequalities, which express a sufficient condition for switched linear systems global stability. The solution of the previously mentioned output feedback control design problem through a linear matrix inequality based method is the main contribution of the present paper. An academic example borrowed from literature is used for illustration.

Delayed Output Feedback Control for Nonlinear Systems With Fuzzy Observers

2012 ◽  
Author(s):  
Mansour Karkoub ◽  
Tzu Sung Wu
Keyword(s):  
Feedback Control ◽  
Nonlinear System ◽  
Nonlinear Systems ◽  
Output Feedback ◽  
Tracking Error ◽  
Sufficient Conditions ◽  
Output Feedback Control ◽  
Linear Matrix ◽  
External Disturbances ◽  
Control Scheme

In this paper, the design problem of delayed output feedback control scheme using two-layer interval fuzzy observers for a class of nonlinear systems with state and output delays is investigated. The Takagi-Sugeno type fuzzy linear model with an on-line update law is used to approximate the nonlinear system. Based on the fuzzy model, a two-layer interval fuzzy observer is used to reconstruct the system states according to equal interval output time delay slices. Subsequently, a delayed output feedback adaptive fuzzy controller is developed to override the nonlinearities, time delays, and external disturbances such that the H∞ tracking performance is achieved. The linguistic information is developped by setting the membership functions of the fuzzy logic system and the adaptation parameters to estimate the model uncertainties directly for using linear analytical results instead of estimating nonlinear system functions. The filtered tracking error dynamics are designed to satisfy the Strictly Positive Realness (SPR) condition. Based on the Lyapunov stability criterion and linear matrix inequalities (LMIs), some sufficient conditions are derived so that all states of the system are uniformly ultimately bounded and the effect of the external disturbances on the tracking error can be attenuated to any prescribed level and consequently an H∞ tracking control is achieved. Finally, a numerical example of a two-link robot manipulator is given to illustrate the effectiveness of the proposed control scheme.

scholarly journals H∞Output-Feedback Tracking Control for Networked Control Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Sung Hyun Kim
Keyword(s):  
Feedback Control ◽  
Control Systems ◽  
Output Feedback ◽  
Networked Control Systems ◽  
Output Feedback Control ◽  
Single Step ◽  
Linear Matrix ◽  
Tracking Problem ◽  
Transmission Delays ◽  
Feedback Control Systems

This paper investigates the observer-basedH∞tracking problem of networked output-feedback control systems with consideration of data transmission delays, data-packet dropouts, and sampling effects. Different from other approaches, this paper offers a single-step procedure to handle nonconvex terms that appear in the process of designing observer-based output-feedback control, and then establishes a set of linear matrix inequality conditions for the solvability of the tracking problem. Finally, two numerical examples are given to illustrate the effectiveness of our result.

Robust Control of Automotive Active Seat-Suspension System Subject to Actuator Saturation

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Zhou Gu ◽  
Shumin Fei ◽  
Yaqin Zhao ◽  
Engang Tian
Keyword(s):  
Controller Design ◽  
Actuator Saturation ◽  
Input Saturation ◽  
Output Feedback Control ◽  
Suspension System ◽  
Linear Matrix ◽  
Control Input ◽  
State Variables ◽  
Sampled Data ◽  
Seat Suspension

This paper deals with the problem of robust sampled-data control for an automotive seat-suspension system subject to control input saturation. By using the nature of the sector nonlinearity, a sampled-data based control input saturation in the control design is studied. A passenger dynamic behavior is considered in the modeling of seat-suspension system, which makes the model more precisely and brings about uncertainties as well in the developed model. Robust output feedback control strategy is adopted since some state variables, such as, body acceleration and body deflection, are unavailable. The desired controller can be achieved by solving the corresponding linear matrix inequalities (LMIs). Finally, a design example has been given to demonstrate the effectiveness and advantages of the proposed controller design approach.

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