Modeling and controlling a quarter-vehicle active suspension model

This paper presents an application of the LQR active suspension control algorithm for a vertical planar oscillation model developed for ¼ of a vehicle. The wheel smoothness and dynamics with the road surface are two parameters to provide control signals. A simulation model is developed here based on MATLAB software to compare and evaluate the LQR active suspension model with the passive suspension. The results obtained here shows an improvement for a number of parameters when utilizing the active suspension model including fluctuating amplitude; oscillation damping time; the displacement acceleration of the active suspension body.

Exposure to Whole-Body Vibration in Commercial Heavy-Truck Driving in On- and Off-Road Conditions: Effect of Seat Choice

Trucking is a key industry in Canada with around 180 000 professional drivers. As an industry it has a disproportionately high injury claim rate, particularly for back injuries. Whole-body vibration (WBV) can contribute to the onset and development of low back disorders, and is a well-documented exposure among driving professions. A widely adopted WBV mitigation measure focuses on hydraulic and/or pneumatic passive suspension systems both in the driver’s seat and underneath the vehicle cab. Passive suspension ‘air-ride’ seats are the current industry standard but new technologies such as the electromagnetic active vibration cancelling (EAVC) seats offer potentially substantial improvements in WBV reduction. In this paper, we evaluate and compare four commonly used truck seats (three air-ride, one EAVC) for their vibration damping characteristics and WBV exposure attenuation in on- and off-road conditions. We recruited 24 professional truck drivers who drove 280 km (mixed on-road and off-road) in ore-haul trucks under four different seating conditions. Following the ISO 2631-1 WBV standard, vibration measurements were made on the cab floor and seat pad, and 8-h average weighted vibration (A(8)) and 8-h vibration dose values (VDV(8)) were calculated, as well as the Seat Effective Amplitude Transmissibility (SEAT), and daily vibration action limits (DVALs). These measures were compared between seat types, as well as road conditions. The EAVC seat gave best performance for both A(8) (0.27 m s−2) and VDV(8) (6.6 m s−1.75). The EVAC seat had the lowest SEAT tested (36.2%) and the longest DVAL. However, among the three passive air-suspension seats, two showed significantly reduced A(8) (0.43 and 0.44 m s−2) and VDV(8) (9.1 and 9.3 m s−1.75) exposures relative to the third passive air-suspension seats [A(8) (0.54 m s−2) and VDV(8) (11.1 m s−1.75)]. These differences in exposures among the three passive air-suspension seats resulted in varying DVAL times, with the worst performing seat reaching the DVAL after only 6.3 h of driving. There was also a seat by road type interaction; there were performance differences between the passive air-suspension seats on-road, but not off-road. The observed reduction of the WBV exposures measured from the EAVC seat was consistent with previous results. But we showed that there can also be substantive differences among seats that are the current industry standard. These differences were more evident on-road than off-road, which suggests that more work needs to be done to understand seat performance characteristics, and in matching the correct seat technology to the driving task. We demonstrated that WBV exposures in current industry conditions may exceed health-based exposure limits; this has policy relevance because WBV exposures are linked to prevalent and costly adverse health conditions in a working population that is ageing. Increased WBV measurement collection is recommended to ensure the anticipated exposure attenuations are achieved when seats are relied upon as an engineered control against WBV.

Improving the Comfort of the Vehicle Based on Using the Active Suspension System Controlled by the Double-Integrated Controller

When the vehicle moves on the road, many external factors affect the vehicle. These effects can cause oscillation and instability for the vehicle. The oscillation of the vehicle directly affects the safety and comfort of passengers. The suspension system is used to control and extinguish these oscillations. However, the conventional passive suspension system is unable to fully meet the vehicle’s requirements for stability and comfort. To improve these problems, these are much modern suspension system models that have been used in the vehicle to replace the passive suspension system. The modern suspension systems are used as the air suspension system, semiactive suspension system, and active suspension system. These systems which are controlled automatically by the controller were established based on the control methods. There are a lot of control methods which are used to control the operation of the active suspension system. These methods have their advantages and disadvantages. Almost, conventional control methods such as PID, LQR, or SMC are commonly used. However, they do not provide optimal efficiency in improving a vehicle’s oscillation. Therefore, it is necessary to establish a novel solution for the active suspension system control to improve the vehicle’s oscillation. In this paper, the method of using the double-integrated controller is proposed to solve the above problem. The double-integrated controller consists of two hydraulic actuators which are controlled completely separately. This is a completely novel and original method that can provide positive effects. This research focuses on establishing, simulating, and evaluating the novel control method (the double-integrated control) for the active suspension system. The results of the research have shown that when the vehicle is equipped with the active suspension system which is controlled by the double-integrated controller, the maximum values of displacement and acceleration of the sprung mass are significantly reduced. They reach only 6.25% and 9.10% (case 1) and 6.00% and 6.12% (case 2) compared to the conventional passive suspension system. Besides, its average values which are calculated by RMS are only about 3.91% and 4.67% (case 1) and 4.48% and 4.77% (case 2) compared to the above case. Therefore, the comfort and stability of the vehicle have been improved. This paper provides new concepts and knowledge about the double-integrated control method which will become the trend to be used in the next time for the systems of the vehicle. In the future, experimental procedures also need to be conducted to be able to more accurately evaluate the results of this research.

Intelligent Cuckoo Search Algorithm of PID and Skyhook Controller for Semi-Active Suspension System using Magneto-Rheological Damper

This article introduces the application of the Cuckoo Search (CS) Algorithm to tune Proportional-Integral-Derivative (PID) and Skyhook controller for the semi-active (SA) suspension system further to improve the vehicle’s ride comfort and stability. Meanwhile, the PID-CSA and Skyhook-CSA intelligent approaches have been compared to the passive suspension system. The performances of the PID controller and Skyhook controller are optimised by Cuckoo Search (CS) Algorithm, respectively. The system’s mean square error (MSE) is defined as an objective function for optimising the proposed controllers. The performance of the proposed PID-CSA and Skyhook-CSA controllers are evaluated with the passive suspension system in the form of body acceleration, body displacement, and tire acceleration. The sinusoidal road profile is set as the disturbance of this system. The percentage improvement for body acceleration and body displacement achieved about 25% for the PID-CSA controller and 1-4% for Skyhook-CSA. These simulated results reflect that the proposed controllers outperformed in comparison with other considered methods to obtain the most effective vehicle stability and ride comfort.

Comparative Study between Type I and Type II Fuzzy Controller for Semi Active Suspension System

In this article, a type-2 fuzzy interval controller is proposed to solve the nonlinear control problems of semi-active suspension system. A suspension model with two degrees of freedom and A fuzzy approach for controller synthesis were proposed. The performance of the IT2FLC-based semi-active vehicle suspension system in terms of sprung mass displacement, suspension deflection and tire deflection are compared to the homologous fuzzy type-1 controller (T1FLC), and to the passive suspension system conventional using MATLAB / SIMULINK software for simulation and controller design. The vehicle parameters, called suspension deflection and speed of suspended mass are given as inputs for both controllers. The Csemi control signal is the variable damping coefficient. Inputs and outputs are presented by triangular membership functions. Mamdani inference system is used, along with a Karnik-Mendel algorithm to locate the center of gravity in reduction type for IT2FLC controller. Simulation results show that IT2FLC-based semi-active suspension system outperforms T1FLC and passive suspension system. Thus, they show a major improvement in control signal i.e. IT2FLC controller generates a lower damping coefficient than T1FLC controller. In addition, a remarkable reduction in signal energy by IT2FLC compared to same semi-active suspension system with T1FLC.

The Theoretical Study of an Interconnected Suspension System for a Formula Student Car

When it comes to racing applications, the primary engineering goal is to increase the performance envelope of the vehicle for a given set of tires. To achieve this goal, it is necessary to maximize the normal loads on the wheels while at the same time minimizing the tire load variation. The purpose of this paper is to present a mathematical model for a Formula Student car in order to study if performance gains are achieved by replacing the traditional passive suspension with a hydraulically interconnected suspension system. To have a complete picture of the advantages and disadvantages of each system, two vibrating models with 7 degrees of freedom were created in order to simulate the motion response of a Formula Student car to realistic excitations. Two particular interpretations of the results were chosen as important performance indicators. The first one is given by the pitch stability of the chassis relative to the road, which can be linked with a decrease in downforce load variation. The second one is the ability of the wheel to follow the road profile as closely as possible, which can be directly correlated with the amount of mechanical grip of the vehicle. The simulation results indicate that the hydraulically interconnected suspension system offers better results for both proposed cases but at the expense of the roll stability of the vehicle.

Ride comfort analysis of driver seat using super twisting sliding mode controlled magnetorheological suspension system

In order to improve the ride comfort of the driver, a higher-order Sliding Mode Controller was proposed in this study for a semiactive magnetorheological (MR) suspension system. The work is mainly focused on improving the ride comfort of the driver with simultaneous improvement in road holding capability of the vehicle and to study the effects of using Super Twisting Sliding Mode Controller (STSMC) in a quarter car with driver seat model. The modified Bouc-Wen model was simulated using MATLAB/Simulink software and the STSMC was adopted to control the voltage variation in MR damper using Continuous State Control (CSC) algorithm. The controller and the suspension system parameters were analysed in time domain with random road inputs. Fast Fourier Transform (FFT) analysis was also carried out to show the effectiveness of the controller towards improving the driver seat comfort. The STSMC-controlled MR damper was used as a primary suspension and the effectiveness of its controllability was compared with passive suspension system. The uncontrolled MR suspension system was also analysed in order to verify the fail-proof advantage of the MR damper. From the results, it was found that the ride comfort was extremely improved when STSMC controller was used than when the uncontrolled MR and passive suspension systems were employed. The uncertainty of the STSMC was verified for different passenger masses and it achieved a robust control over load variation. The selected STSMC was validated with the first-order Sliding Mode Controller and the results were discussed in terms of time-domain analysis.

Computation of passive suspension parameters for improvement of vehicle ride quality based on stochastic optimal controller with a look-ahead preview

This article aims to determine the optimum parameters of a half-car model passive suspension vehicle passing on a random road. The optimum parameters are obtained based on the response of linear quadratic regulator control with a look-ahead preview for attaining the passive suspension performance nearly equivalent to the active suspension performance. The optimum parameters are estimated by equalizing mean square suspension controlling forces of passive and active vehicle models and subsequently minimizing the performance error between the two systems. The response of passive suspension with optimized parameters matches approximately with the active suspension response, with respect to ride comfort and road holding.

Optimization of Nonlinear Passive Suspension System to Minimize Road Damage for Heavy Goods Vehicle

Major contributors to the road damage are Heavy Goods Vehicles (HGV), resulting in high maintenance costs of roads. This high cost makes it necessary to look into the issue seriously for minimizing the road damage. An Automobile Engineer can reduce road damage through the efficient design of a suspension system. The design involves satisfying the two conflicting criteria of riding comfort and vehicle handling with the restriction on the suspension travel. This paper involves designing an automobile suspension system, to improve the performance of the vehicle without a significant change in the cost of the suspension system and minimize road damage. To achieve the aforesaid objective, the use of a nonlinear passive suspension is suitable as compared to a linear passive suspension system. For the analysis, a HGV model of vehicle suspension has been considered. The suspension system considered for investigation comprises of a cubical nonlinear spring and a linear damper. Road damage has been represented by the fourth power of the tire dynamic load. A genetic algorithm has been used to optimize the half truck model to minimize road damage. The solution has been obtained using MATLAB and SIMULINK.