Sliding mode control of active suspension system

The purpose of this paper is to present a new approach in controlling an active suspension system. This approach utilized the proportional integral sliding mode control scheme. Using this type of sliding surface, the asymptotic stability of the system during sliding mode is assured compared to the conventional sliding surface. The proposed control scheme is applied in designing an automotive active suspension system for a quarter-car model and its performance is compared with the existing passive suspension system. A simulation study is performed to prove the effectiveness of this control design

VHDL-AMS based genetic optimisation of fuzzy logic controllers

Purpose – This paper presents a VHDL-AMS based genetic optimisation methodology for fuzzy logic controllers (FLCs) used in complex automotive systems and modelled in mixed physical domains. A case study applying this novel method to an active suspension system has been investigated to obtain a new type of fuzzy logic membership function with irregular shapes optimised for best performance. Design/methodology/approach – The geometrical shapes of the fuzzy logic membership functions are irregular and optimised using a genetic algorithm (GA). In this optimisation technique, VHDL-AMS is used not only for the modelling and simulation of the FLC and its underlying active suspension system but also for the implementation of a parallel GA directly in the system testbench. Findings – Simulation results show that the proposed FLC has superior performance in all test cases to that of existing FLCs that use regular-shape, triangular or trapezoidal membership functions. Research limitations – The test of the FLC has only been done in the simulation stage, no physical prototype has been made. Originality/value – This paper proposes a novel way of improving the FLC’s performance and a new application area for VHDL-AMS

Modeling, Design and Simulation of Active Suspension System Frequency Response Controller using Automated Tuning Technique

Car suspension system is a mechanism that separates the car from the tire. The objective of the suspension system is to improve a ride quality by ensuring passenger’s comfort and good car road handling when the car is subjected to an input excitation. The dynamics of the suspension system was mathematically modeled. The system transfer function determined. The suspension system performance characteristics of overshoot and settling time set at not more than 5% and 5seconds respectively. Frequency response controller was designed by using the MATLAB function sisotool in the automated tuning technique. The result of the simulation indicated that the overshoot and settling time 2.97% and 3.95seconds respectively. The design requirement satisfied. Keywords: Suspension, active, Frequency response

Skyhook-PID Control Strategy to Improve Performance of a Pneumatic Active Suspension System

The research applies a skyhook-PID control method for an active suspension system. The control strategy has three feedback control loops. They are the innermost loop for the force tracking of the pneumatic actuator, the intermediate loops applying skyhook strategy for the elimination of the disturbances, and the outermost loop using PID controller for the determination of the desired force. Some experiments were carried out on a physical test rig with a hardware-in-the-loops feature. The performance of the proposed control method was evaluated and benchmarked to examine the effectiveness of the system in suppressing the disturbance effect of the suspension system. It was found that the experimental results demonstrate the superiority of the active suspension system with Skyhook-PID scheme compared to the PID and passive suspension systems

Modeling, Design and Simulation of Active Suspension System Root Locus Controller using Automated Tuning Technique.

Car suspension system is a mechanism that separates the car from the tire. The objective of the suspension system is to improve a ride quality by ensuring passenger’s comfort and good car road handling when the car is subjected to an input excitation. The dynamics of the suspension system was mathematically modeled. The system transfer function determined. The suspension system performance characteristics of overshoot and settling time set as not more than 5% and 5seconds respectively. PID controller was designed by using the MATLAB function sisotool in the automated tuning technique. The result of the simulation indicated that the overshoot and settling time 3.53% and 4.92seconds respectively. The design requirement satisfied. Keywords: Suspension, active, Root Locus

Electromagnetic hybrid active-passive vehicle suspension system

The suspension systems currently in use can be classified as passive, semi-active and active. The passive suspension systems are the most commonly used due to their low price and high reliability. However, this system can not assure the desired performance from a modem suspension system An important improvement of the suspension performance is achieved by the active systems. Nevertheless, they are only used in a very reduced number of automobile models because they are expensive and complex. Another disadvantage of active systems is the relatively high energy consumption. The use of electromagnetic linear actuators is an alternative for the implementation of active suspensions. Moreover, this solution has the advantage of the suspension energy recovery. In spite of the materials development, the electromagnetic actuators are yet expensive to produce. In this paper it is proposed an hybrid suspension system which combines the simplicity of the passive dampers with the performance of an electromagnetic active suspension. Maintaining the passive damper, it is possible to keep the performance of the active suspension, but using a smaller electromagnetic actuator

On the Observability and Controllability of Active Suspension System

The focus of this paper is on the controllability and observability of an active suspension system used in automobile. The primary responsibility of control system Engineers is to design and implement controller. The active suspension system dynamics was captured by a mathematical model. The system transfer function model was determined by using the road disturbance as input and the car response as output. The state – space representation was subjected to controllability and observability test using MATLAB commands. The result of the test shows that the rank of the state matrix was (4) which is equal to the state matrix dimension. The active suspension system is both state controllable and observable. Keywords: Controllability, Observability, Active Suspension

Half Car Active Suspension System

This paper presents a new method in modeling an active suspension system for a half-car model in state space form and develop a robust control strategy in controlling the active suspension system. Fuzzy logic is used to control the system. Velocity and displacement of front wheels are taken as input variables of the fuzzy logic controller. Active forces improving vehicle driving, ride comfort and handling properties are considered to be the controller outputs. The controller design is proposed to minimize chassis and wheels deflection when uneven road surfaces, pavement points, etc. are acting on the tires of running cars. Comparison of performance of active suspension fuzzy control system with passive suspension system is shown using Matlab/Simulink simulation. From the result, it shows that active suspension system has better performance than the passive suspension system

Vibrational control of air suspension system using PID controller

This paper deals with modeling and evaluation of suspension system with a pneumatic actuator controlled by Proportional Integral Derivative (PID) controller. A non-linear mathematical model of the dynamic suspension system with two degrees of freedom is developed. The controller is designed by setting proper gain values obtained by comparing three tuning methods - Ziegler Nicolas, Refined Ziegler Nicolas and Optimal control. The time response of the air suspension system is contrasted with the passive suspension system due to the road disturbance modeled as a single bump input. The proposed model limits suspension travel, minimizes passenger acceleration and keeps body displacement within bound

Pengujian Prototip Suspensi Aktif Tegar (Robust) Model Seperempat Kendaraan

In this paper the result of the performance test of a robust-active suspension system will be presented. The performance of the developed suspension system was evaluated under a sinusoidal road disturbance with amplitude of 3 mm (peak to peak), and within the frequency test range of 1 "“ 9 Hz. The experimental results show that in the frequency test range of 1 "“ 4 Hz, the sprung mass acceleration of the active suspension is smaller than that of the passive suspension. However, the sprung mass acceleration of the active suspension is higher than that of the passive one, in the frequency test range of 5 "“ 9 Hz. Moreover, the unsprung mass acceleration of the active suspension is smaller than its passive counterpart in all of the frequency test range 1 "“ 9 Hz