L1 State Feedback Control of Semi-Active Suspension.

Multipoint interpolation of Volterra series and [formula omitted]-model reduction for a family of bilinear descriptor systems

The main aim of this paper is to attenuate the effects of the road disturbance on the quarter-car active suspension system (ASS) for the passenger comfort by using design. Therefore, a new static disturbance compensator is proposed by using linear matrix inequality method such that the disturbance compensator and feedback controller are simultaneously designed for the disturbances in the linear time-invariant systems, which are measurable or predictable. They have static structure, and the disturbance compensator is designed on the feedforward path. The design is applied against the road disturbance affecting the quarter car ASS. The effectiveness of the design is demonstrated with the simulations.

This paper studies the stabilization of the discrete‐time bilinear system , where A and B are bounded linear operators on a pre‐Hilbert space H, by means of a new nonlinear state feedback control which is uniformly bounded. First, sufficient conditions for uniform exponential stabilization are given, and the decay rate of the state is estimated. Then global weak stabilization is investigated under less stringent assumptions. In the case of the finite dimension, easily verified conditions for uniform stabilization are given. Moreover, a decomposition method allows additional stabilization results. Finally, illustrative examples are provided.

We propose an algorithm for nonlinear receding-horizon output feedback control by combining a real-time nonlinear optimal state feedback control algorithm and a real-time nonlinear optimal state estimation algorithm. The algorithms of state feedback control and state estimation are obtained by minimizing receding-horizon performance indexes. Application of the stabilized continuation method results in algorithms that do not involve any successive approximation methods. Simulation results of a 2-wheeled car clarify characteristics of the output feedback control algorithm.

This brief addresses the problem of control for active vehicle suspension systems in finite frequency domain. The performance is used to measure ride comfort so that more general road disturbances can be considered. By using the generalized Kalman-Yakubovich-Popov (KYP) lemma, the norm from the disturbance to the controlled output is decreased in specific frequency band to improve the ride comfort. Compared with the entire frequency approach, the finite frequency approach suppresses the vibration more effectively for the concerned frequency range. In addition, the time-domain constraints, which represent performance requirements for vehicle suspensions, are guaranteed in the controller design. A state feedback controller is designed in the framework of linear matrix inequality (LMI) optimization. A quarter-car model with active suspension system is considered in this brief and a numerical example is employed to illustrate the effectiveness of the proposed approach.

A controller is designed for automotive active suspension whose purpose is to improve the ride comfort against road disturbances. This disturbance rejection problem is formulated as an l/sub 1/ control problem, i.e., minimization of the effects of disturbances in terms of the l/sub /spl infin//-induced norm. Since l/sub 1/ control theory minimizes the maximum possible amplification of signal magnitude, the l/sub 1/ controller can specify the maximum magnitude of outputs in the time domain, regardless of the frequency of road disturbances. To design a static full state feedback controller, Shamma's l/sub 1/ near-optimal control theory is applied. Although l/sub 1/ control with full state feedback usually can be dynamic and of arbitrarily high order, this theory with a certain approximation is able to construct a simple static state feedback with nonlinearity. Therefore, for a linear quarter vehicle model, a nonlinear controller is designed. Finally, satisfactory performances of the controller are confirmed by numerical analysis.

This paper investigates the dynamic output-feedback control problem for active suspension systems subject to actuator faults in finite frequency domain. Unmeasured states and uncertain parameters are considered in the controller design process. By using the generalized Kalman-Yakubovich-Popov (KYP) lemma, an H ∞ controller can be obtained in specific frequency band. The H ∞ controller is used to make passengers ride comfort under road disturbance. Moreover, the constraints of active suspension systems can be guaranteed depended on the designed controller. Finally, simulations are presented to illustrate the effectiveness of the proposed controller.

• Proposed a dynamic energy management system for hybrid sources in an electric vehicle. • Buck-boost H-bridge converters are introduced for bidirectional power flow control. • System non-linearities are addressed using a nonlinear state feedback controller. • The proposed system accurately delivers instantaneous vehicle speed and torque. This paper describes a methodology to control a multi-source battery-capacitor hybrid EV incorporating a dynamic power splitting strategy. Considering the requirement for precise speed control characteristics of the EV and the non-linear behavior of traction motor with system disturbances, a non-linear state feedback controller (NLSFC) with a disturbance observer is suggested as the speed control technique for the EV traction motor. To interface a parallel configured multi-source system, a non-inverted buck-boost H-bridge is proposed as the source side converter for effective recovery of the braking energy. Detailed control design for traction motor and converter is also presented for efficient control of EV. Besides, an adaptive energy management strategy considering power profile and dynamic source characteristics is incorporated into the overall control system. The simulation results from various case studies indicate that the proposed system can follow the required vehicle speed and torque despite the sudden change in EV load torque. Furthermore, the comparative analysis between NLSFC and PI controller shows improvement with steady-state error reduction from 0.43 to 0.0014 and peak overshoot drop from 12.07% to 3.51% during acceleration of the system when proposed NLSFC is adopted. The proposed solutions will be implemented in a prototype EV system in the future.

Generation of multi-wing chaotic attractor in fractional order system

The response of a Duffing–van der Pol oscillator under delayed feedback control

<div class="htmlview paragraph">As an important class of nonlinear system, polytopic bilinear system is investigated. Combined with the properties of convex polytope, the nonlinear control for polytopic bilinear system is formulated by synthesizing nonlinear <i>H</i><sub>∞</sub> controller which is designed for polytopic bilinear system at vertices. For a semi-active suspension system with controllable damping and variant stiffness elements, it is easily modeled as a polytopic bilinear system model. In this case, the desired nonlinear control properties are pursued in making effective use of the changeable damping property while the variant stiffness is taken as the affine parameter of polytopic model. Therefore, polytopic bilinear system model could be reduced to a feasible problem by polytopic convex decomposition. Then the control problem of bilinear system model is to find a solution of nonlinear <i>H</i><sub>∞</sub> control. Here, the merits in using nonlinear <i>H</i><sub>∞</sub> state feedback control are that it can confine the damping force output to 1<sup>st</sup> and 3<sup>rd</sup> phase planes where changeable damping force is produced and its nonlinear control output makes a fast state origin convergence in keeping small vibration and motion. In this paper, a practical control design demonstration for a polytopic bilinear suspension system is described after the theory description. The simulation study and experimental results demonstrate the effective control performance in improving ride comfort.</div>

A procedure based on neural networks for the classification of linear and nonlinear systems is presented, using excitation and response data under swept sine excitation. Special attention is paid to the classification and identification of linear and bilinear systems, the latter being considered since they exhibit typical characteristics of cracked systems. The computer simulations show that: (1) using the procedure presented in this paper the trained classification network can reliably classify a linear system and different nonlinear systems; (2) the output of the trained identification neural network for a linear system and a bilinear system can be used as a quantitative indicator of characteristics of bilinear systems having different stiffness ratios (k(x>0)/k(x<0)) with respect to the bilinear system used in the training stage; (3) for two-degree-of-freedom systems, the trained network can not only determine the existence of a bilinear stiffness and the magnitude of its stiffness ratio, but also specify which stiffness is bilinear, i.e. indicate its position. These results provide a possibility of using the trained neural networks to detect and locate structural cracks which have the characteristics of bilinear systems.

This research introduces a more accurate control oriented model that can be applied in the suspensions performance domain towards comfort and stability improvement. Active suspension based on Magnetorheological (MR) dampers is an attractive solution in improving vehicle stability and passenger comfort. These Dampers are highly nonlinear and their modeling and control is a challenge. The multi-model approach is applied to describe the highly nonlinear two-degrees-of-freedom (2-DOF) one-quarter-vehicle semi-active suspension with an MR damper. The objective is to show that an MR damper, represented by the Bouc-Wen approach, is suitable for control purposes. Passenger comfort and vehicle stability are translated into constraints on a controlled output. Therefore, the control problem aims to attenuate the effect of the road profile which is considered as an exogenous input. This problem is solved using the H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> techniques applied to the non linear system. Due to the multi-model nature of the system description, the controller is obtained from Linear Matrix Inequalities conditions. A numerical case and simulation work support the results.

Data-driven MIMO model-free reference tracking control with nonlinear state-feedback and fractional order controllers

Output feedback control of switched nonlinear systems using multiple Lyapunov functions