Suspension Damping Research Articles

The active control of the lateral movement of a motor suspended under a high-speed locomotive

In order to improve the dynamic performance of high-speed locomotives, an active control method for the movement of a suspended motor is proposed, in which a damper is replaced by an actuator. A simplified mechanical model of the flexible suspension system is established to study its dynamics and create an active control strategy. Then, a multi-body dynamic model of the locomotive is simulated to obtain the conditions for optimal control. The results show that a smaller damping of the lateral suspension is conducive to improving the dynamic performance of the locomotive; the system has a theoretical optimum damping ratio of between 0.1 and 0.3. A small level of damping results in a large lateral displacement of the suspended system, which cannot be allowed to occur due to space limitations. The optimal control is used with the aim of reducing the lateral vibration amplitude of the suspended motor system and bogie frame. The active control of the suspension system improves the lateral dynamic performance of the locomotive and effectively limits the lateral displacement of the suspended system relative to the bogie frame. Compared with a passive suspension approach, the lateral forces on the wheelset are reduced by up to 25% at speeds between 140 and 180 km/h on straight track, and the nonlinear critical speed is increased from 390 to 480 km/h.

Motorized vehicle active suspension damper control with dynamic friction and actuator delay compensation for a better ride quality

This paper describes motorized active suspension damper control with dynamic friction and actuator delay compensation for an enhanced ride quality. The control algorithm consists of a supervisory controller, an upper-level controller and a lower-level controller. The supervisory controller determines the control modes, such as the passive control modes and the active control mode. The upper-level controller, which incorporates the existing actuator delay, computes the damping force using linear quadratic control theory. The actuator input is determined by the lower-level controller by compensating the dynamic friction torque. To estimate the sprung-mass displacement, the sprung-mass velocity, the unsprung-mass displacement and the unsprung-mass velocity, two state estimators are proposed. An adaptive observer is developed for the non-linear dry friction to estimate the ball-screw dynamic friction caused by the axial movement of the actuator and the viscosity. The performance of the proposed control algorithm was evaluated from simulations. It was shown from simulations that the proposed motorized active suspension damper control with a friction and delay compensation algorithm can improve the ride quality.

NeuroFuzzy Adaptive Control for Full-Car Nonlinear Active Suspension with Onboard Antilock Braking System

In this paper, the dynamic behavior of the nonlinear full-car model having active suspensions with nine degrees of freedom including driver, passenger seats and antilock braking system (ABS) is analyzed. The comfort analysis of a driver and passengers of the full car with active suspension model including all forms of nonlinearities is very rare in the literature. The literature also lacks the comfort analysis of the driver and passengers, while the car accelerates and decelerates during cornering. The nonlinearities in the proposed model include the dry friction nonlinearities of the suspension dampers and the geometric nonlinearities of the four corners of the car chassis. Modified adaptive NeuroFuzzy Takagi–Sugeno–Kang (NFTSK) control strategies are presented for the vehicle active suspension control to improve the ride quality, road holding capability and vehicle stability. Separate control strategy is used for ABS to avoid wheel locking and slipping for providing better road–wheel contact. The paper also investigates the coordination of active suspensions and ABS to further enhance the performance of the ABS control. To validate the performance of the proposed intelligent control strategies, the response of the vehicle nonlinear model due to road irregularities is evaluated using various performance indexes. The results are then compared with passive control to verify the performance of modified adaptive NFTSK control.

Experimental Fault Diagnosis in Systems Containing Finite Elements of Plate of Kirchoff by Using State Observers Methodology

This paper presents a methodology for detection and localization of faults by using state observers. State Observers can rebuild the states not measured or values from points of difficult access in the system. So faults can be detected in these points without the knowledge of its measures, and can be track by the reconstructions of their states. In this paper this methodology will be applied in a system which represents a simplified model of a vehicle. In this model the chassis of the car was represented by a flat plate, which was divided in finite elements of plate (plate of Kirchoff), in addition, was considered the car suspension (springs and dampers). A test rig was built and the developed methodology was used to detect and locate faults on this system. In analyses done, the idea is to use a system with a specific fault, and then use the state observers to locate it, checking on a quantitative variation of the parameter of the system which caused this crash. For the computational simulations the software MATLAB was used.

Investigation of Slow-Active Suspension System’s Non-linearity on The Performance of The Anti-lock Brake System

This paper presents an advanced integrated controller design for military vehicle slow-active suspension system and anti-lock brake system (ABS) considering the effect of the suspension components non-linearity on the braking dynamics. The presented investigation is applied to a quarter vehicle model using the Magic Formula tire model and the actual characteristics for suspension damper (throttle valve) and spring (gas spring). The suspension controller is designed based on LQR using a linearized vehicle model and the ABS controller is designed based on ON/OF control methodology using tire skid ratio of 15% as a reference value. The mathematical derivations as well as the control techniques are numerically implemented in MATLAB environment. Several simulation results are carried out considering typical performance measures such as stopping time, stopping distance and vehicle body vertical acceleration. The results illustrated that, the integrated controller reduces the stopping distance on different road surfaces and therefore improves the braking performance to avoid or reduce the impact of vehicle accident.

Influence of the Longitudinal and Lateral Suspension Damping on the Vibration Behaviour in the Railway Vehicles

Abstract The paper focuses on the influence of the longitudinal and lateral suspension damping in correlation with the velocity upon the vibration behaviour of the railway vehicles while moving on a tangent track. The numerical simulations are developed based on a linear model of a 17-degree of freedom vehicle that allows the evaluation of the dynamic behaviour of the vehicle in a sub-critical velocity. Based on the response frequency functions of the vehicle in a harmonic and in a random behaviour, a series of basic properties of the stable behaviour of the forced lateral vibrations has been made evident, as well as the opportunities to lower the level of the carbody vibrations by changing the suspension damping.

Simultaneous Optimization of Semiactive Quarter Car Suspension Parameters using Taguchi Method and Grey Relational Analysis

In present paper, a methodology is presented related to the optimization of semi-active quarter car model suspension parameters having three degrees of freedom, subjected to bump type of road excitation. Influence of primary suspension stiffness, primary suspension damping, secondary suspension stiffness and secondary suspension damping are studied on the passenger ride comfort, taking root mean square (RMS) values of passenger seat displacement and settling time into account. Semi-active quarter car model assembled with magneto-rheological (MR) shock absorber is selected for optimization of suspension parameters using Taguchi method in combination with Grey relational analysis. Confirmatory results with simulation run indicates that the optimized results of suspension parameters are helpful in achieving the best ride comfort to travelling passengers in terms of minimization of passenger seat displacement and settling time values.

Assessing the effectiveness of probe vehicle acceleration measurements in estimating road roughness

In this article, we compare roadway roughness measured using a probe vehicle with roadway roughness calculated from the measured profile using an inertial profiler. Roughness is characterised by vehicle body vertical acceleration and probe vehicle roughness index (PVRI), which approximates the international roughness index (IRI) of a full car (rather than a quarter car). The reason the PVRI is used rather than the IRI is that acceleration measurements obtained from a probe vehicle represent the response of the full car rather than a quarter car. An important aspect of this article is that the same physical quantities are compared rather than obtaining a correlation between two different physical quantities. The results suggest that the roughness calculated from probe vehicle measurements is comparable with the roughness calculated from the measured profile; however, the investigation also revealed that data sampling frequency and quarter car parameters, specifically suspension damping and tyre stiffness, can have a significant effect on the measured PVRI.

Experimental investigation on a controllable colloidal damper for vehicle suspension

Experimental investigation on a controllable colloidal damper for vehicle suspension

Ride comfort enhancement of heavy vehicles using magnetorheological seat suspension

This paper investigates the application of a controlled MR damper for a semi-active seat suspension for heavy vehicles, enabling more appropriate control algorithm. The proposed control system consists of a system controller that calculates the desired damping force using a proportional integral derivative (PID) controller tuned using genetic algorithm (GA), and a continuous state damper controller that estimates the command voltage that is required to track the desired damping force. The controlled semi-active seat suspension is compared to a passive seat suspension for predetermined base displacements. These inputs are calculated separately from the vibration of the body mass of a passive quarter-vehicle suspension. System performance criteria are evaluated in both time and frequency domains, in order to verify the effectiveness of the proposed semi-active control algorithm. The generated results show that the proposed genetic PID controller of MR seat suspension offers a considerable enhancement of the ride comfort.

Effect Analysis of Vehicle System Parameters on Dynamic Response of Pavement

In order to study the damage of a semirigid pavement under vehicle loads with varied parameters, the random dynamic loads applied on the pavement by a running vehicle were computed with two degrees of freedom, quarter-vehicle model, and then a three-dimensional finite element analysis model of semirigid asphalt pavement was established. With the peak stress index of each pavement layer, the effect of varied vehicle parameters on pavement response was studied. The results indicated that the stress wave frequency of each pavement layer was similar to that of the dynamic random load, and, with increased pavement depth, the wave effect decreased. The pavement response increased with increased suspension stiffness and tire stiffness and decreased with increased suspension damping and tire damping. Furthermore, compared to the stiffness, the response variation induced by the damping was orders of magnitude lower. Compared with the traditional time response analysis method, the peak response analysis of the pavement structure was more scientific, rational, and intuitive, which could be useful for the study of vehicle-pavement interaction and road damage.

Modeling and Analysis of Static and Dynamic Characteristics of Nonlinear Seat Suspension for Off-Road Vehicles

Low-frequency vibrations (0.5–5 Hz) that harm drivers occur in off-road vehicles. Thus, researchers have focused on finding methods to effectively isolate or control low-frequency vibrations. A novel nonlinear seat suspension structure for off-road vehicles is designed, whose static characteristics and seat-human system dynamic response are modeled and analyzed, and experiments are conducted to verify the theoretical solutions. Results show that the stiffness of this nonlinear seat suspension could achieve real zero stiffness through well-matched parameters, and precompression of the main spring could change the nonlinear seat suspension performance when a driver’s weight changes. The displacement transmissibility curve corresponds with the static characteristic curve of nonlinear suspension, where the middle part of the static characteristic curve is gentler and the resonance frequency of the displacement transmissibility curve and the isolation minimum frequency are lower. Damping should correspond with static characteristics, in which the corresponding suspension damping value should be smaller given a flatter static characteristic curve to prevent vibration isolation performance reduction.

A state feedback input constrained control design for a 4-semi-active damper suspension system: a quasi-LPV approach

This paper addresses a semi-active suspension control of the full vehicle equipped with 4 controlled semi-active dampers by using a full 7 degree of freedom (DOF) vertical model. First, the dissipativity conditions of the semi-active dampers are recast as saturation conditions on the control inputs. Then, the suspension controller is derived by solving a state feedback control design problem for a class of linear parameter-varying (LPV) system in the presence of actuator saturation. To this aim, a generalized sector condition for LPV system is applied to treat the nonlinearity, caused by the input saturation and to relax the stability condition. The proposed control law ensures the disturbance attenuation by reducing the L2 gain from the disturbance to the controlled output. This controller, derived in the LPV/H∞ framework, is based on the LMI solution for polytopic systems. Some realistic simulation results are presented in order to illustrate the effectiveness of the proposed approach.

Tyre force control strategy for semi-active magnetorheological damper suspension system for light-heavy duty truck

A semi-active controller scheme for magnetorheological (MR) damper of a light-heavy vehicle suspension known as Tyre Force Control (TFC) is proposed. The effectiveness of the proposed TFC algorithm is compared with Groundhook (GRD) control. A simulation model was developed and simulated using MATLAB Simulink software. The performance of the semi-active MR damper using TFC is analytically studied. Ride test was conducted at three different speeds and two different bumps, and the simulation results of TFC and GRD are compared and analysed. The results showed that the proposed controller is able to reduce tyre force significantly compared to GRD control strategy.

Investigation on Emergency Brake Property of a Heavy-Duty Vehicle Based on Functional Virtual Prototyping Model

A Functional Virtual Prototyping full vehicle model for a tri-axial heavy-duty truck is built, and the non-linearity of suspension dampers and tires is also considered. With the trajectory of full vehicle gravity center, longitudinal tire force of front wheel, longitudinal acceleration, lateral acceleration, yaw rate and pitch angle as the evaluation indexes of brake property, the influences of system parameters including wheelbase, load shift, road surface roughness and separated road friction coefficient on brake efficiency, stability and ride comfort are analyzed. In addition, the interaction of brake and full vehicle dynamics is studied. Results show that small wheelbase and load shift may improve the brake efficiency of vehicles, small road surface roughness is beneficial to brake stability and ride comfort, and great frictional coefficient difference of separation road will worsen the brake efficiency and stability.

Nonlinear adaptive control of semi-active MR damper suspension with uncertainties in model parameters

This paper is concerned with vibration mitigation of a quarter car model using a semi-active magnetorheological (MR) damper. A nonlinear adaptive controller is proposed for vibration attenuation of the quarter car suspension system equipped with MR damper. Proposed adaptive controller can also compensate the uncertainties related to both quarter car model and the MR damper. Moreover, a nonlinear observer is designed to estimate an internal state variable of the MR damper. The mathematical model of the damper which is strongly nonlinear is used to predict the damping force based on velocity input, internal state and voltage input. An experimental test set-up is constructed to validate the MR damper parameters which are adapted by designed controller. Efficiency of adaptive controller is compared with separately designed linear $$\hbox {H}\infty $$ controller and passive cases under bump, sine and C-grade road inputs. The proposed adaptive controller is able to achieve good performance in road holding and driving comfort despite uncertainties in model parameters.

Design of Automobile Shock Absorber Based on Throttle Type Adjustable Damping

With the deepening of reform in the industrial sector, automotive manufacturing technology has been greatly improved. Suspension damping effect of the traditional shortcomings of poor correlation analysis suspension constituted by employees, starting from the improved shock absorber damping valve, designed and developed Nepal adjustable shock absorber set, in order to improve traffic safety and create favorable conditions. This damper is in the computing speed and power, the analysis of the relationship between the motor and the throttle on the invention came. Practice has proved that through adjustable automobile shock absorber damping curve smoothing, deformation is not obvious, the stepper motor rotation into correspondence with the damping force, with better value.

Smart Fluid Self Adaptive Damper System (SFSADS)

This paper is on fluid damper systems, which is self-adaptive and used to increase the speed and acceleration of vehicles. In normal dampers there is a time lag leading to break in contact between the wheel and the road reducing the acceleration. Now, our idea is about making the suspension adapt to varying road conditions. Due to irregularities in asphalt, a change occurs in the suspension damper position with the aid of the magnetic field and causes the suspension to change from softer to harder and vice versa giving more acceleration and increasing the pace of the vehicle.

Non-Parametric Modelling and Validation of Magnetorheological Damper for Lateral Suspension of Railway Vehicle Using Interpolated Sixth Order Polynomial

Passenger ride comfort is an important factor in railway vehicle services. However, passenger ride comfort is sometimes affected by the vibrations resulting from the track irregularities. It will be critical when the track is exposed to prolonged sun’s heat and lack of track maintenance. This means that the optimization of passive suspension parameters alone could not cope with these cases. Semi-active suspension system for railway vehicles has been developed as a way to solve these problems. The technology of semi-active suspension is widely used especially in the railway vehicle application. Magnetorheological (MR) damper is one of the applications of the concept of semi-active suspension. However, there are a variety of criteria for MR dampers based on usage. To meet the requirements of railway vehicle suspension system, a MR damper have been developed. The criteria for the MR damper are obtained experimentally. Then, the model for the MR damper is developed using Interpolated Sixth Order Polynomial and validated by experimental. The MR damper model has shown improvement, especially in the railway vehicle dynamics performance.

Integrated control of the differential braking, the suspension damping force and the active roll moment for improvement in the agility and the stability

This paper describes an integrated control strategy of the differential braking, the semiactive suspension damper and the active roll moment. Integrated control is designed to improve the agility and the stability of a vehicle by simultaneous control of the yaw rate and the roll motion. The proposed integrated chassis control algorithm consists of a supervisor, vehicle motion control algorithms and a coordinator. The supervisor monitors the vehicle status and determines the desired vehicle motions such as the desired yaw rate and the desired roll motion based on control modes to improve the stability and the agility of the vehicle. The control algorithm calculates the desired yaw moment and the desired roll moment for generation of the desired vehicle motions. The coordinator determines the brake pressures, the damper current and the active roll moment to generate the desired yaw moment and the desired roll moment. The roll moment and the yaw moment can be controlled simultaneously by the use of the active anti-roll bar motor torque. Open-loop and closed-loop simulations of a driver–vehicle–controller system were conducted to investigate the performance of the proposed control algorithm. The performance of the proposed integrated chassis control algorithm was compared with those of the individual chassis control systems, such as the electronic control suspension and the an active roll control system. It was shown from the simulation results that the proposed integrated chassis control system can provide a significantly improved performance with respect to the agility, the manoeuvrability and the roll stability of a vehicle compared with the performances of the individual chassis control systems.