Publications

Vehicle crash test is considered to be the most direct and common approach to assess the vehicle crashworthiness. However, it suffers from the drawbacks of high experiment cost and huge time consumption. Therefore, the establishment of a mathematical model of vehicle crash which can simplify the analysis process is significantly attractive. In this paper, we present the application of LPV-ARMAX model to simulate the car-to-pole collision with different initial impact velocities. The parameters of the LPV-ARMAX are assumed to have dependence on the initial impact velocities. Instead of establishing a set of LTI models for vehicle crashes with various impact velocities, the LPV-ARMAX model is comparatively simple and applicable to predict the responses of new collision situations different from the ones used for identification. Finally, the comparison between the predicted response and the real test data is conducted, which shows the high fidelity of the LPV-ARMAX model.

In this paper, the problem of robust synchronization and fault detection for a class of master-slave systems subjected to some nonlinear perturbations and mixed neutral and discrete time-varying delays is investigated based on an H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> performance condition. By introducing a descriptor technique, using Lyapunov-Krasovskii functional and a suitable change of variables, new required sufficient conditions are established in terms of delay-dependent linear matrix inequalities to synthesize the residual generation scheme. The explicit expression of the synchronization law is derived for the fault such that both asymptotic stability and a prescribed level of disturbance attenuation are satisfied for all admissible nonlinear perturbations. A numerical example with simulation results illustrates the effectiveness of the methodology.

This paper deals with modelling and adaptive output tracking of a Transverse Flux Permanent Magnet Machine (TFPM) as a non-linear system with unknown nonlinearities by utilizing High Gain Observer (HGO) and Radial Basis Function (RBF) networks. The technique of feedback linearization and H ∞ control are used to design an adaptive control law for compensating the unknown nonlinearity parts, such the effect of cogging torque, as a disturbance is decreased onto the rotor angle and angular velocity tracking performances. Finally, the capability of the proposed method is shown in the simulation results.

Focusing on the issue of nonlinear stability control system about the single-stage inverted pendulum, the T-S fuzzy model is employed. Firstly, linear approximation method would be applied into fuzzy model for the single-stage inverted pendulum. At the same time, for some nonlinear terms which could not be dealt with via linear approximation method, this paper will adopt fan range method into fuzzy model. After the T-S fuzzy model, the PDC technology is utilized to design the fuzzy controller secondly. Numerical simulation results, obtained by Matlab, demonstrate the well-controlled effectiveness based on the proposed method for the model of T-S fuzzy system and fuzzy controller.

This paper studies the problem of guaranteed cost control for spacecraft evacuation. The relative dynamic model is established based on Clohessy-Wiltshire (C-W) equations. The paper has taken parameter uncertainty, output tracking, disturbance attenuation, and fuel cost into consideration. The paper introduces a new Lyapunov approach, so the controller design problem can be transferred into a convex optimization problem subject to linear matrix inequality (LMI) constraints. By using the controller, the spacecraft evacuation can be completed in a safe extent. Meanwhile, the fuel cost also has an upper bound. Then the paper analyzes the approach of evacuation and discusses possible initial states of the spacecraft for the controller design. An illustrative example is applied to show the effectiveness of the proposed control design method, and different performances caused by different initial states of spacecraft (-V-bar, -R-bar, and +H-bar) are simulated.

Notice of Violation of IEEE Publication Principles <br><br> After careful consideration by a duly constituted committee, an author of this article, Hamid Reza Karimi, was found to have acted in violation of the IEEE Principles of Ethical Publishing by artificially inflating the number of citations to this article. <br/> This paper addresses the issue of robust fuzzy sliding mode control for continuous-time nonlinear Takagi-Sugeno fuzzy systems with semi-Markovian switching. The focus is on designing a novel fuzzy integral sliding surface without assuming that the input matrices are the same with full column rank and then developing a fuzzy sliding-mode controller for stochastic stability purpose. Based on Lyapunov theory, a set of newly developed linear matrix inequality conditions are established for stochastic stability of the sliding-mode dynamics with generally uncertain transition rates, and then extended to where the input matrix is plant-rule-independent, as discussed in most existing literatures. Furthermore, finite-time reachability of the sliding surface is also guaranteed by the proposed fuzzy sliding-mode control laws. A practical example is provided to demonstrate the effectiveness of the established method numerically.

No abstract is provided for this article.

Sub-optimal multi-user joint-detection (JD) is an effective technique for combating the effects of multiple-access interference in CDMA communication systems. Its implementation, however, is accompanied by a prohibitive computational complexity when supporting large numbers of asynchronous users and channels with long impulse responses. Two approaches for the reduction of this complexity are compared. The first is based on an approximate Cholesky factorization. The second is based on iterative schemes such as the method of conjugate gradients or the Jacobi algorithm and its derivatives. The two approaches result in significant reductions in complexity at the expense of little or no degradation in performance. Results are presented for the asynchronous multi-rate environment of the WCDMA uplink with exact and realistic channel estimates.

Vehicle crash modeling and reconstruction is an important field for research since the safety statistics from many countries show that the fatality rate of passenger vehicle occupants involved in road accidents is high. In particular, side impact are considered to be a serious problem. For this reason, in this paper, there is presented a methodology to reconstruct a given vehicle to road safety barrier oblique collision. An easy to analyze, viscoelastic model is established to represent a vehicle crash event. The reasonable modeling simplifications are assumed (namely: the vehicle is rigid and deformation of the safety barrier is negligible) which let the computational efficiency of the proposed approach improve, whereas simultaneously does not affect the accuracy of the simulation results. The Levenberg–Marquardt algorithm is applied to estimate parameters of the two-dimensional Maxwell model which represents a vehicle oblique collision. The obtained results verify that the fidelity of such a model is high and its behavior closely resembles the kinematics of the reference fullscale vehicle.

This paper investigates the stability problem for a class of uncertain genetic regulatory networks (GRNs) with time-varying delay via delta operator approach. Both the parameter uncertainty and the generalized activations are considered in the model under study. By constructing an appropriate Lyapunov–Krasovskii functional, the stability and robust stability conditions of GRNs are presented under the delta operator frame. These conditions can be expressed in terms of linear matrix inequalities (LMIs). Finally, a numerical example is employed to illustrate the effectiveness of the proposed results.

Nowadays, each newly produced car must conform to the appropriate safety standards and norms. The most direct way to observe how a car behaves during a collision and to assess its crashworthiness is to perform a crash test. Because of the fact that vehicle crash tests are complex and complicated experiments it is advisable to establish their mathematical models. This paper contains an overview of the kinematic and dynamic relationships of a vehicle in a collision. There is also presented basic mathematical model representing a collision together with its analysis. The main part of this paper is devoted to methods of establishing parameters of the vehicle crash model and to real crash data investigation i.e. - creation of a Kelvin model for a real experiment, its analysis and validation. After model's parameters extraction a quick assessment of an occupant crash severity is done.

In this paper, some small-gain conditions are presented for stochastic network systems which can describe many large-scale systems with interconnections, nonlinear behaviors, uncertainties and random disturbances. One subsystem is selected as monitor with the requirement that the gains to other systems are smooth concave functions. The relations of members under the supervise of the monitor are described as bilateral plus multilateral relations of gains. For the deterministic case, the requirement on the monitor can be removed. To demonstrate the power of this result, the small-gain conditions cover interconnected system with two subsystems as a special case. Compared with the existing results, the main character is that the forward completion of system and ultimate uniform boundedness of input are removed from conditions of small-gain theorems.

This chapter presents several important definitions and lemmas needed in the study of fractional calculus theory and system stability theory, providing essential theoretical support for subsequent research. Fractional calculus extends the concept of integer-order differentiation and integration to noninteger orders, offering a powerful tool for modeling various physical and engineering processes. System stability theory, on the other hand, addresses the behavior of dynamic systems over time, ensuring that they remain within desired bounds and do not exhibit undesirable behavior. By laying down the foundational concepts and theoretical constructs in these areas, this chapter serves as a critical reference point for further exploration and application in advanced research. The definitions and lemmas provided here are crucial for developing a deeper understanding and for solving complex problems in these fields.

Engineering, IITRAM, Ahmedabad and Department of Mechanical Engineering, IIT Bhilai.This conference provides a forum for discussion on issues, concepts, skill development and possible innovations in the mechanical infrastructure sector.ICRAM-2022 aims at bringing the best technical minds working in the field of mechanical engineering on a common platform to share their knowledge of technical expertise, experience and forthcoming challenges in the development of infrastructure of the country.

This paper deals with the problem of stability analysis for discrete‐time switched positive linear systems with unstable subsystems. The fundamental concept involves utilizing the stability properties of switching behavior to counteract the state divergence introduced by unstable systems. Moreover, the existing results in the literature lack a method that can simultaneously address the stability analysis of switching positive systems containing only stable subsystems or containing unstable subsystems or only unstable subsystems. Therefore, in this paper, based on the widely used discretization Lyapunov function method in time‐delay systems, a new dwell‐time dependent co‐positive Lyapunov function was proposed by applying it to switched positive systems. A computable sufficient condition for stability analysis of switched linear systems with unstable subsystems was established within the dwell time framework. To verify the effectiveness of the results, this paper provides a numerical example and an example of supersaturated cross signal control for illustration, as well.