Active Vibration Control of Automotive Suspension System using Fuzzy Logic Algorithm

The performance of active suspension systems is directly related to the mechanical design and control of the system. The stable operation of the controller improves driving comfort and handling. The quarter car model is frequently used in the analysis of suspension systems due to its simple structure. In this study, Matlab Simulink software was used in the modeling, control and simulation of the quarter car active suspension model. System performance was investigated for four different road profiles with PID and fuzzy logic control methods. Two of the road profiles used are in the form of impact signals consisting of pits and bumps. The other two road profiles are random road disturbances with high frequency. The effects of active and passive suspension systems on driving comfort are compared by taking into account the control methods used. As a result of the study, it has been determined that the fuzzy logic controller gives better results in pulse signals consisting of bumps and pits, and the PID controller gives better results in high-frequency random road disturbances. In addition, with the use of fuzzy logic control method in the active suspension system, a significant decrease in the actuator force has occurred. This result is very interesting in terms of minimizing energy, reducing actuator sizes and reducing costs.

This study designs a fuzzy logic controller (FLC) for an active automobile suspension system in which the membership functions and control rules are optimized using a genetic algorithm (GA). The objective of the FLC is to strike an optimal balance between the ride comfort and the vehicle stability. The values of the crossover and mutation parameters in the GA are adapted dynamically during the convergence procedure using a fuzzy control scheme. The convergence state of the GA is determined by using a support vector machine (SVM) method to identify the variation in each of the genes of the best-fit GA chromosome following each iteration loop. The feasibility of the proposed GA-assisted FLC scheme is verified by performing a series of numerical simulations in which the characteristics of the controlled plant are compared with those observed in a passive suspension system and obtained under an optimal linear feedback controller. The results demonstrate that the GA-assisted FLC results in a lower suspension deflection, a reduced sprung mass acceleration and a lower bouncing distance between the tire and the ground.

Passenger ride comfort is considered to be of utmost importance in designing any suspension system. The primary objective of any suspension system in automobiles is to isolate the road disturbances experienced by the tyres from being transmitted to the passengers. ISO- 2631-1:1997(E) has provided certain guidelines to analyse ride comfort and also indicates the degree to which the vibration exposure will be acceptable. Hence active suspension systems are becoming crucial to improve ride quality and passenger comfort, in view of the established superiority over conventional systems. In this paper considering direction of vibrations acting on human body in the translational vertical direction of the coordinate system, bump analysis is carried out on a 3 DOF quarter car model. Since the system dynamics change with increase in the Degrees of freedom, fuzzy logic control is used to control active suspension of a 3-DOF quarter car model. The objective function of the fuzzy logic control has been defined to minimize the sprung mass acceleration and seat acceleration, and is evaluated by simulating the transient response to road perturbations. In this paper the study is extended to a quarter car (3-DOF) seat-suspension model instead of 2 DOF suspension systems, since the vibrations are transmitted to human body through broad contact area like buttocks when sitting. The performance parameters, chassis acceleration, seat acceleration, seat displacement and chassis displacements are analyzed and also the ride comfort levels are analyzed according to ISO-2631-1:1997(E). Results indicate more ride comfort to the occupants through the active suspension system with the proposed fuzzy controller rather than the passive suspension system.

The primary aim of a vehicle's suspension system is to isolate the vehicle's main body from road irregularities, thus improving passenger comfort and ensuring optimal handling stability. This research discusses a stabilizing fuzzy control design for active vehicle suspension systems. The nonlinear model of the active suspension is then represented using a Takagi-Sugeno (TS) fuzzy model. The control approach uses a TS fuzzy controller utilizing an observer to estimate the state while reducing road disturbances. The closed-loop stability requirements of the vehicle utilizing the fuzzy controller and observer are expressed as a Linear Matrix Inequalities (LMI) problem, which can be effectively resolved through convex optimization methods. In this paper, we study the stability of the nonlinear automotive active suspension system with two degrees of freedom represented by a TS fuzzy model, where we will present the stabilization conditions by state feedback via the PDC (Parallel Distributed Compensation) control law and in the last section we introduced the TS fuzzy observer for the case of non-measurable premise variables.

Suspension system plays most significant role in supporting the vehicle weight and isolating vehicle body from road shocks and vibrations. The aim of suspension system is to suppress uncomforting situations from road unevenness to driver and passengers and to provide road handling and stability of vehicles. The aim of this research work is to design efficient active controller for active suspension system for improving ride quality and road holding that can tackle different types of road input conditions. By using mathematical modeling 2 Degree Of Freedom (DOF) Quarter Car Model is designed. Linear Quadratic Regulator (LQR) and Fuzzy logic controller which are capable of considering disturbances have been designed. Three different road profiles such as Step, Sine and Band limited white noise are taken as input disturbances. In this work, MATLAB/SIMULINK software is used for simulation purpose and simulation result demonstrate that proposed active suspension system shows excellent performance by improving road holding, ride comfort, reduced peak overshoot and reduced settling time in comparison to passive suspension system for all the road profiles. LQR controller gives extremely good performance improving up to 96%.

Suspension system is used to fulfil the criteria of ride comfort and road handling. In this paper, a quarter car active & semi-active suspension systems are designed using Matlab/Script software. Comparison of active & semi-active suspension systems are done using robust control theory for the control targets suspension deflection, body acceleration and body travel. H infinity controller is selected to compare the two suspensions using time domain analysis. Finally the simulation result prove the effectiveness of the active suspension system by decreasing the body acceleration & sustaining the suspension deflection and body travel outputs.

Active suspension (AS) system is primarily responsible for vehicles' ride quality and safety enhancement. However, the high power demand and fast dynamics of this system confine its application in conventional vehicles. Fuel cell hybrid electric vehicles (FCHEVs) are local zero-emission HEVs with a promising perspective in the transportation section and, due to their comprehensive energy storage system (ESS), can well supply the AS's power demand. Although AS load can increase fuel consumption and limit the driving range of FCHEVs, the energy regeneration of the AS system may compensate for this augmented fuel consumption and even contribute to further fuel economy. A regenerative AS system is proposed for a passenger FCHEV. The AS system comprises four independent regenerative fuzzy AS systems. The ESS is a combined battery/ultracapacitor system responsible for powering the AS system and capturing the regenerated energy based on the proposed energy regeneration scheme. The energy management system (EMS) is also a central fuzzy logic controller (FLC) that determines the power split between the power sources. Simulation results reveal that the AS load increases fuel consumption and accelerates ESS degradation. However, regeneration of the AS load can effectively improve fuel economy and FC aging.

<div class="section abstract"><div class="htmlview paragraph">The design of the conventional passive suspension has always been a compromise between vehicle handling and comfort, which led to the development of the modern active and semi active suspension systems. Amongst these, semi-active suspension has been focus of research in recent years owing to its lesser complexity and less power consumption as compared to active suspension.</div><div class="htmlview paragraph">Semi active suspension uses real time variation in damping coefficient which can be achieved by using various control strategies. It is observed from available literature that Skyhook (for better ride comfort), Groundhook (for better vehicle handling) and Hybrid are most widely used strategies. These strategies use ‘On-Off’ control strategy (i.e. two preset values of damping co-efficient) but a better control over damping coefficients can be achieved using Continuous Control strategy. This paper aims to implement Continuous control strategy using Fuzzy logic for the semi active suspension. For the analysis, Two degree of freedom Quarter car model is used which is excited by three road profiles namely Bump, Sine Wave and Swept Sine wave. Comparison is done on the basis of vehicle parameters: Body displacement, Wheel displacement, Suspension working space and Dynamic tire deflection. Also frequency response of system is analysed using Fast Fourier Transform. Simulation is done using MATLAB SIMULINK and results of ‘Continuous control strategy’ are compared with the results of ‘On-Off control strategy’ and ‘Passive suspension’. Continuous control strategy using Fuzzy Logic control was found to provide better overall performance with 22.1% reduction in body displacement, 11.66% reduction in dynamic tire deflection and 31.77% reduction in suspension working space. Also Fuzzy logic control retained its stability over whole frequency range.</div></div>

In this paper, the semi-active suspension in railway vehicles based on the controlled Magnetorheological (MR) fluid dampers is examined, and compared with the semi-active low and semi-active high suspension systems to enhance the running safety, ride quality and ride comfort for a high-speed rail vehicle. Fuzzy logic and chaotic fruit fly control techniques are used as system controllers to determine desired damping forces for front and rear bogie frame with force track-ability of system controllers. A 28 degrees of freedom (DoF) mathematical model of the rail vehicle is formulated using nonlinear vehicle suspension and nonlinear heuristic creep model. The Modified Dahl model is formulated to characterize the behavior of the MR damper. The simulation result is validated using the experimental results. Four different suspension strategies are proposed with MR damper i.e. passive, semi-active low, semi-active high and semi-active intelligent compound controller based on bio-inspired chaotic fruit and fuzzy logic hybrid controller. A comparison indicates that the semi-active controller gives the optimum performance based on frequency and time response analysis for comfort vibration actuation (9.088 to 15.33%), ride quality (14.81–20.73%) and comfort (24.91–27.81%) and it has little influence on derailment quotients, offload factors, as a result, it will not endanger the running safety of rail vehicle.

In pursue of a comfortable vehicle driving in different road profiles, intelligent methods used to improve the suspension system of the vehicle. Semi-active suspension system outperformed other suspension systems because it contains an intelligent actuator that can give the appropriate force to dissipate unwanted vibration using intelligent and real-time controllers. Here in this paper MR fluid damper with Fuzzy-PID controller examined to optimized using modified DE algorithm. However, in the Fuzzy-PID controller, the fuzzy logic algorithm is used to autotune the PID controller, but it cannot be considered as a fully real-time controller since the fuzzy algorithm uses a previous knowledge base built offline. The offline design of Fuzzy algorithm cannot cope with real-time unexpected vibrations occurred while driving car in different road profiles. In this paper, a Fuzzy-DE-PID controller proposed based on modified DE algorithm to enhance the Fuzzy logic gains in order to increase vehicle semi-active suspension system performance. To prove the effectiveness of the proposed controllers, a simulation and experimental tests were conducted using the proposed controller with different disturbances. The results of the simulation and the experimental tests for the proposed controller showed improvement of the vehicle’s ride comfort over the Fuzzy-PID and the passive system. We believe that using this proposed controller in any other real-time application will improve the performance to the highest levels without the need for a previous knowledge base for designing a real-time Fuzzy-PID controller.

On a flat city road, the specificity of the suspension poses a challenge. Sport utility vehicles (SUVs) have less flexibility compared to regular cars, despite providing a firm grip on asphalt and concrete. Constant adjustments to the center of gravity of SUVs are necessary. Surprisingly, they are less reliable and stable in urban settings due to this characteristic. In this study, a mathematical model of the suspension system of SUVs based on the Newtonian approach is introduced and validated with data from experiments carried out by the MTS machine system on the mono-tube (oil/air) mixed damper element. The model accurately predicts the performance of this damper, commonly used in SUVs, across various operating conditions, including different frequencies. A coil spring element, serving as a passive suspension unit with this damper, is also tested experimentally under similar conditions. By integrating passive suspension elements with the active actuator, the proposed modified design reduces the power consumption needed for the actuator to function and ensures a certain level of reliability. The effectiveness and performance of the modified active suspension system in comparison to the traditional passive suspension system are assessed using three different strategies: hybrid PID-LQR, linear quadratic regulator (LQR), and proportional-integral-derivative (PID). The genetic algorithm is utilized to determine the optimal parameter values for each controller by minimizing a cost function, maximizing performance, and minimizing energy consumption. Simulation results demonstrate that the active suspension system controlled by the PID-LQR controller offers significantly improved ride comfort and vehicle stability compared to other systems. This suggests that the performance of the active suspension system is greatly enhanced by the combined application of the hybrid PID-LQR controller compared to other systems.

A passive suspension system is used by the automotive industry to control the motion of the vehicle. Nowadays, semiactive and active suspension systems are a requirement of commercial vehicles to improve performance characteristics and road comfort. The objective of the paper is to present a comprehensive analysis of passive, semiactive, and active suspension systems. The fuzzy logic controller is used to present the active suspension system. The characteristic of the shock absorber (damper) is non-linear and hysteresis in nature. Hence, a Magneto-rheological (MR) damper-based Bouc-Wen model is utilized to present the semiactive suspension. The comparative analysis of vehicle suspension characteristics has been carried out by using a bump road profile. The modeling of the Bouc-Wen model and quarter car system is carried out in the Simulink environment. The simulated results show that the semiactive and active suspension systems can be a better option for vehicle suspension systems to provide passengers with road comfort.

Actuator is the key to vehicle active suspension. Based on the analyses of traditional passive suspension and active suspension system, a novel vehicle active suspension with Electro-Hydrostatic Actuator (EHA) is put forward. The system consists of two parts: spring and actuator with variable control force. The actuator is made up of hydraulic cylinder, hydraulic pump, controller and BLDCM. According to bond graph principles, bond graph model of 2 DOF passive suspensions and bond graph model of EHA active suspension are built. Moreover, fuzzy logic controller is designed and fuzzy control active suspension is simulated using MATLAB tools. The prototype and test rig of EHA active suspension are developed and bench tests are carried out. The simulation and experimental results show that fuzzy control active suspension with EHA provides better ride comfort, handling and stability than passive suspension.

<div class="section abstract"><div class="htmlview paragraph">The performance of suspension system has a direct impact on the riding comfort and smoothness. For the traditional suspension can not effectively alleviate the impact of road surface and the poor anti-vibration performance, The dynamics model of vehicle suspension system is established, and the control model of vehicle four-degree-of-freedom active suspension is designed with fuzzy control strategy. On this basis, a comprehensive simulation model of the control model of vehicle active suspension coupled with road excitation is established. and the ride comfort of vehicles under different types of suspension are tested through Simulink. The simulation results show that compared with the passive suspension, the reduction of vehicle acceleration and dynamic deformation of the active suspension controlled by fuzzy PID can reach 33.76% and 22.45%. and the reduction of pitch Angle speed and dynamic load of the active suspension controlled by fuzzy PID can reach 16.18% and 10.72%. Under fuzzy PID control, the amplitude of each evaluation index of active suspension in the suspension system is substantially reduced than that of the passive suspension, and the root-mean-square value decreases by about 10% on average. It can be seen that the active suspension with fuzzy PID control can improve the performance of the suspension system on the basis of ensuring the stability and rapid response of the system, and can well reduce the random vibration caused by the impact of the vehicle on the random road surface during the driving process, improve the ride comfort, smoothness and ride safety of the vehicle, and achieve a good control effect on the vehicle suspension.</div></div>

A suspension system is responsible for driver comfort and safety. It isolates car body from road disturbances. A quarter car suspension is a suspension of 1/4th car body mass. Suspension system has three types: passive, semi-active and active. A passive suspension has fixed damping rates determined by their design. Semi-active and active suspension uses selective damping rates. In active suspension, energy is added externally to change damping coefficient. This paper focuses on the development of modeling for 2 DOF and control algorithm in order to adjust damping rates of damper according to road disturbances. This paper proposes advanced Fuzzy Logic Controller (FLC) to minimize sprung mass displacement and Suspension Working Space (SWS) using MATLAB Simulink.