Linear Suspension Research Articles

Performance improvement study of nonlinear bionic suspension based on inerter and on–off control strategy

How to improve the dynamic performance of nonlinear suspension systems is a focus of attention. The combination of inerter and on–off control strategy can effectively improve the dynamic performance of linear suspension systems, but it will also bring some adverse effects. This paper puts forward a nonlinear suspension system performance enhancement scheme based on semi-active on–off control strategies of inerter to eliminate the adverse effects of the introduction of the inerter and to enhance the dynamic performance of nonlinear suspension systems. This paper takes the nonlinear double-diamond bionic kangaroo leg suspension system as an example and adopts the above scheme to carry out dynamic modeling, time–frequency domain dynamic characteristics analysis, and control characteristics research. The results show that the dynamic performance of the proposed nonlinear suspension system with passive inerter is partially better than that of the original suspension system in time–frequency domain, while the overall dynamic performance of the proposed nonlinear suspension system with semi-active inerter is better than that of the original suspension system. The proposed nonlinear suspension system with semi-active inerter shows good stability and adaptability under different working conditions, and the proposed control strategies can eliminate the adverse effects of passive inerter. The above results indicate the correctness of the proposed scheme and the effectiveness of the control strategies.

A Comparative Study of Particle Swarm Optimized Control Techniques for Active Suspension System

This work presents a comparative study for performance evaluation of quarter vehicle Active Suspension System (ASS) using different control techniques. Linear and non-linear mathematical models of the systems are presented and controlled using Proportional Integral Derivative (PID), Feedback Linearization, and Fuzzy Logic Control (FLC). Particle Swarm Optimization (PSO) technique is applied to optimize the gains of the implemented controllers. A simulation process is done using MATLAB/SIMULINK and the results show that the proposed PSO-optimized PID controller has enhanced the root mean square (r.m.s) values of ride comfort, load carrying, and road holding of the linear suspension system by 26.82%, 20.95%, and 22.72% respectively compared to the linear passive suspension system. Whereas, for the nonlinear suspension system, the PSO-optimized FLC has provided better compromise of the performance criteria. The controller has improved the r.m.s values of ride comfort, load carrying, and road handling by 40.61%, 44.21%, and 27.46% respectively compared to the non-linear passive suspension system.

Vibration Control of Quarter Car Model Using Modified PID Controller

The purpose of this research is to control a quarter car suspension system and also to reduce the fluctuated movement caused by passing thevehicle over road bump using modified PID (Proportional Integral and Derivative) controller. The proposed controller deals with dual loopfeedback signals instead of single feedback signal as in the conventional PID controller. The structure of the modified PID controller wascreated by moving the proportional and derivative actions in the feedback path while remaining the integral action in the forward path. Thus,high accuracy results were obtained. Firstly, modelling and simulation of linear passive suspension system for a quarter car system wasperformed using Matlab – Simulink software. Then the linear suspension system was activated and simulated by using an active hydraulicactuator to generate the necessary force which can be regulated and controlled by the proposed controller. The performance of whole systemhas been enhanced with a modified PID controller.

Matching, Stability, and Vibration Analysis of Nonlinear Suspension System for Truck Cabs

To improve comfort, a nonlinear suspension system is proposed on the basis of the nonlinear vibration isolation theory and the installation space of the cab suspension system for trucks. This system is suitable for all‐floating cabs. For easy matching and design, the static and stability characteristics of the suspension system were analyzed, respectively, and the boundary condition for the stability of the system was given. Moreover, the cab simulation model was established, and the dynamic simulation was conducted. The stability analysis shows that the smaller the vibration excitation of the cab system, the higher its stability is. The dynamic simulation results show that the acceleration of the cab with the nonlinear suspension system is effectively suppressed; the dynamic deflection of the suspension is kept within a certain range, and the design space of the suspension stroke can be effectively utilized. Compared with the traditional linear suspension system, the nonlinear suspension system has better vibration isolation characteristics and can effectively improve ride comfort.

Research on Ride Comfort of Nonlinear Vehicle Suspension

In this paper, in order to study the effect of nonlinear suspension system, a nonlinear dynamic model considering nonlinearity of suspension is built and another model with the respective of linear suspension system is developed which is for comparison. Then the dynamic equation of the model is set up. The simulation is accomplished through MATLAB/SIMULINK. It is found that the band-limited white noise module can simulate the power spectral density of road surface well. Finally, numerical simulation results indicates that an appropriate nonlinear suspension model fits reality better than a linear one and using relative control can provide the best ride comfort.

A new passive non-linear damper for automobiles

Passive linear suspension systems are limited in their ability to improve ride characteristics owing to the conflicting interdependence between ride comfort, road holding, and space occupied by the suspension system. Non-linear systems can improve the performance of passive designs by de-linking the various metrics involved in ride comfort. Based on the control strategies used in semi-active suspensions, a new non-linear damper design is proposed, where the damping rapidly changes with stroke. This design has been fabricated and tested to validate the analytical expressions governing the damping as a function of stroke. Experimental results show excellent agreement with analytical expressions. The novel damper model has been used along with an existing non-linear spring design, in a quarter-car simulation. The results indicate that the non-linear design leads to significantly lower acceleration levels when compared with a linear system, without any compromise on other metrics.

Heave-Pitch-Roll Dynamics of Flexible Vehicle in Variable Velocity Run

Analysis for response statistics evaluation of a flexible vehicle travelling with variable velocity over nonhomogeneously profiled flexible track is presented with a heave-pitch-roll model. The vehicle body is idealised as a flexible member with variable cross-section, inertia, damping and stiffness distributions. The vehicle may also have variable section slender elastic attachments. Coupled dynamics with rigid body heave-pitch-roll modes and elastic bending-torsion modes of the vehicle body along with coupled bending-torsion modes of the attachments are considered. Equivalent linear suspension system characteristics are employed for developing the analysis. Numerical results are presented for an aircraft with tricycle landing gear arrangements and comparison is made with other models.