Cab Suspension Research Articles

Experimental Validation of Truck Cab Suspension Model and Ride Comfort Improvement under Various Semi-Active Control Strategies

The semi-active cab suspension system for trucks is gaining increasing importance due to its economic advantages, low energy consumption, and significant enhancement of ride comfort. This paper investigates the effects of three control methods on improving ride comfort of semi-active cab suspension systems under random and bump road conditions: Proportional-Integral-Derivative (PID) control, fuzzy PID control, and Model Predictive Control (MPC). Initially, an accurate multi-degree-of-freedom truck cab suspension model was developed and validated through actual road tests. Based on this model, three control strategies were designed and implemented. Finally, the effectiveness of each control strategy was evaluated under various road conditions, including random and bump road scenarios. The results indicate that these control strategies can effectively reduce vibrations and impacts, significantly improving ride comfort. This improvement is crucial for alleviating driver fatigue and enhancing driving safety. Among them, the MPC control showed superior performance, reducing vibrations by at least 31% under both random and bump road conditions, outperforming PID and Fuzzy PID in terms of effectiveness and robustness.

Design and experimental analysis of magneto-rheological damper featuring a labyrinthic dual-channel valve

For the sake of improving the damping performance of the cab suspension system, the MR damper featuring the labyrinthic dual-channel valve (LDCV-MRD for short) is proposed in this paper, which is composed of a mixture of circular channel, circular disk channel and circular tube channel. The LDCV-MRD is designed structurally and the magnetic circuit is analyzed. The output damping force mathematical model is established, and the coil’s number of turns is computed. The magnetic field in the damping channel of LDCV-MRD is simulated and analyzed. The processed and fabricated LDCV-MRD is tested, and the experimental results are compared and analyzed with the simulation results. The results show that the simulated values of the maximum damping force and the adjustable coefficient fit well with the experimental results. The peak output damping force of the experiment achieves 21 008 N. The adjustable coefficient reaches about 5.61, when the input current gets to 2 A.

Calculation Model for Evaluating Suspensions during Maneuvers of a 4WD Vehicle with a 6x6 Wheels

The article describes the purpose, scope, main parameters of the flowchart of the procedure used to calculate control devices when comparing vehicle suspension structures with a 6x6 wheel arrangement. Methods for comparing suspensions during maneuvers are described. A description of the cab suspension system, a block diagram of the simulation program is presented. The visualization of the process of rebuilding the studied model of a 6*6 vehicle with two different types of front suspension is shown. An estimate of the load on the front and rear axles during the rebuilding for a period of time t = 5 s, their energy output and inertia is given. The distribution of the load along the axes of the investigated 6*6 vehicle model is presented when rebuilding with the front suspension of the first and second types. The coordinates of the base points of the front axle allow you to evaluate the numerical values for specific coordinates at a given point in time.

The method of virtual bench tests conducting to analyze the vehicle technical characteristics compatibility to detect and prevent the risk of resonant phenomena in the sprung cab

BACKGROUND: A relevant issue when designing vehicles with multiple levels of suspension systems is collaborative operation of these systems, which ensures the required vehicle dynamics and smoothness parameters, as well as the absence of risk for the occurrence of resonance phenomena. The vehicle cab is a dynamic system with 6 degrees of freedom, so its oscillatory motions have a complex spatial character with the oscillation energies overflow from one direction to another. The solving of problems of the sprung cab dynamics should be conducted in a spatial nonlinear formulation, which makes it possible to take into account the phenomena of redistribution of oscillation energy between the directions of space. This approach can be put into operation with simulation modeling methods through creating a spatial virtual rig of the cab with a suspension system and modeling its dynamics with the application of appropriate external inputs.
 AIM: Development of the method of using virtual tests to analyze the compatibility of technical characteristics of the cab suspension system, the frame system and the primary vehicle suspension systems to detect and prevent the risk of resonant phenomena in the cab.
 METHODS: Building a virtual test rig of a vehicle cab as a multibody dynamics system of connected bodies in space, mounted at the movable vehicle frame with spring-dampers. Virtual tests are conducted by simulation modeling methods according to the method for analyzing nonlinear phenomena when spatial resonances occur in the secondary suspension system of a vehicle cab.
 RESULTS: The method of vehicle cab virtual tests conducting for analyzing oscillatory processes occurring in the cab, including resonances, using a virtual test rig in a multibody dyamics software package.
 CONCLUSION: The developed method ensures an ability to take measures to detect and prevent the risk of spatial resonance phenomena in the vehicle cab at all stages of the components design and the cab suspension systems study.

Reaction Rod Link in Rear Cab Suspension to Control Cab Dynamics in Tractor-Semitrailer Vehicles

<div>Articulated vehicles form an important part of our society for the transport of goods. Compared to rigid trucks, tractor-trailer combinations can transport huge quantities of load without increasing the axle load. The fifth wheel (FW) acts as a bridge between the tractor and trailer, which can be moved within the range to achieve rated front and rear axle loads. When the FW is moved front, it adversely affects the cab dynamics and cab suspension forces. Compared to the cab pitch and roll, yaw motion increases drastically. The current study tries to address this issue by providing reaction rod links in the rear cab suspension.</div> <div>In this study, a 4×2 tractor with a three-axle semitrailer is considered by keeping the FW at its frontmost position, which is the worst-case scenario for a cab. Three different cases of reaction rod arrangement and its influence on cab dynamics are studied in comparison with a model without reaction rods. To assess this, time signal–based relative pseudo-fatigue damage, power spectral density (PSD), and level crossing plots are analyzed.</div> <div>The outcome shows that cab pitch, roll, and yaw motion reduce by a considerable amount with the presence of a reaction rod. Cab suspension forces will also reduce. The horizontal V-inclination of the reaction rod plays a major role in improving cab yaw motion and reducing the lateral forces. A straight link without any inclination helps in reducing the pitch and roll motion of the cab.</div>

Takagi–Sugeno Fuzzy Model-Based Control for Semi-Active Cab Suspension Equipped with an Electromagnetic Damper and an Air Spring

Variable damping shock absorbers have received extensive attention for their efficient vibration reduction performance, and air springs have also been widely used in high-end commercial vehicles due to their nonlinear stiffness characteristics. This paper presents a novel semi-active cab suspension integrated with an air spring and a variable damping electromagnetic damper (A-EMD). The electromagnetic damper (EMD) prototype was designed, manufactured and tested. Then, due to the interference of nonlinear stiffness characteristics of the air spring with the controller in the subsequent design, the Takagi–Sugeno fuzzy method was adopted to segmentally linearize its nonlinearity, based on which an H∞ state feedback semi-active controller was designed to control the EMD to generate variable damping force. Furthermore, a Luenberger state observer was designed to provide immeasurable state parameters for the controller. Numerical simulations were carried out to validate the effectiveness of the proposed approaches, and the results show that the proposed control strategy can significantly improve the ride comfort of the A-EMD system. The vibration dose value (VDV) acceleration under the bump road and the frequency-weighted acceleration root mean square (FWA-RMS) under the random road decreased by 36.05% and 19.77%, respectively, compared with the passive suspension system.

Nonlinear resonant phenomena in the secondary suspension system of the vehicle cab research

The issue of creating a methodology for analyzing nonlinear phenomena in the occurrence of spatial resonances in the truck cab suspension system is solved in research. The study purpose is the creating of spatial vibrations mathematical model of the cab on the suspension with regard to the car frame and changing the differential equations of the model dynamics to a form that allows visually analyze the nonlinear resonant phenomena arising in the system to research oscillations instability in resonance conditions. The transformation of the oscillation equations to a quasi-linear form is performed using the replacement of the trigonometric functions of Euler angles by the first two terms of their power series expansions. Because of the research, unfavorable frequency ratios for external and internal resonances in the cab suspension system were obtained. Guides are given to reduce the cab on the suspension rocking amplitudes when spatial nonlinear resonances occur. Keywords: nonlinear resonance, secondary suspension system, car cab suspension, mathematical model, quasi-linear view, vibration stability

Performance of semi-active cab suspension system with different control methods

In this study, based on adaptive control methods, the semi-active suspension system of the heavy truck cab is researched and controlled to improve the ride comfort of the heavy truck. A dynamic model of the vehicle is established for simulation. Matlab/Simulink software is used to simulate and calculate the root mean square (RMS) accelerations of the driver’s seat and cab pitch angle under different operation conditions. Proportional-integral-derivate controller with its parameters optimized by the genetic algorithm (GA-PID controller) and Fuzzy logic control combined with PID (FLC-PID controller) are used to control the semi-active cab suspension system of the heavy truck. The obtained results show that the ride comfort of the vehicle using FLC-PID is better improved in comparison with using GA-PID under different operating conditions. Especially, when the vehicle moves at a speed of 72 km/h, the RMS accelerations of the driver's seat and cab pitch angle are greatly reduced by 26.45 % and 26.07 % respectively. Therefore, the FLC-PID control should be applied to the suspension system of the vehicles to improve the vehicle's ride comfort.

Improving the comfort of truck drivers by using controlled cab suspension shock absorbers

The research addresses the issue of creating a methodology for selecting the damping control law in nonlinear suspension systems and determining the characteristics of controlled shock absorbers in the cab suspensions. The study object is the shock-absorbing support device of the truck cab suspension system. By mathematical modeling of the car dynamics, it is proved the effectiveness of the cab suspension system with controlled shock absorbers and its operability according to the criterion of the possibility of implementing a controlled shock support device in the form of a technical device. Keywords controlled shock absorbers, cab suspension, smoothness running, driver comfort, shock support device

Parameter Optimization of the Cab Suspension for Commercial Vehicles Based on the Differential Evolution Genetic Algorithms

Parameter Optimization of the Cab Suspension for Commercial Vehicles Based on the Differential Evolution Genetic Algorithms

Effect of damping rate on fatigue failure tendency of a topology-optimised swing arm for a heavy commercial truck cab suspension

The effect of damping rate on the failure tendency of a truck cab suspension swing arm was numerically investigated. Firstly, the mechanical design of the swing arm was carried out using topology optimisation by taking the standard load cases into account. Displacement differences which occurred in the front cab suspension springs, as a result of the cab roll, were obtained for an uneven road surface by using the Multibody Dynamics (MBD) model of the truck. Using these data, full transient Finite Element (FE) analyses and arm fatigue analysis were conducted for various damping characteristics of the shock absorber. Results showed that, reducing the damping ratio of the shock absorbers by, e.g., 50% in comparison with the reference value, may result in swing arm damage under dynamic loading conditions. Therefore, it was concluded that, damping rate should be considered in the design stage of cab suspension components which can be categorised as a safety system.

Nonlinear Coupled Dynamic Modelling of Driver-seat-cab System and Biomechanical Behaviour Prediction

The biomechanical responses of the driver-truck system in a dynamic environment have become a significant concern in the design and control of trucks. When evaluating the riding comfort of the seat-cab system, it is necessary to predict the biomechanical responses of the driver’s different parts and directions. However, there is no reliable model and method for effectively predicting the response characteristics of the driver-seat-cab system. Aiming at such problem, firstly, based on the 7 DOF (degree-of-freedom) seated human biodynamic model established previously, a 10 DOF non-linear dynamic model of the driver-seat-cab system was created, and its vibration differential equations were established. Secondly, the vibration signals for simulation and verification were collected through the road test using a truck. Thirdly, based on the Newmark-β integration method, the specific solution process of the model was given. The non-linear damping coefficients of the front and rear dampers for the cab suspensions were measured with a bench test. Moreover, the simulations were conducted based on the measured model parameters, taking the collected frame vibration signals as the inputs. The results show that the simulation results agree with the test results, proving that the dynamic model can effectively predict the driver’s biomechanical responses. Finally, some useful conclusions were obtained through the simulation analysis. The established model and conclusions can provide technical support for comfort evaluation, optimization design, and control of the seat-cab suspension system.

Variable universe fuzzy control of the wheel loader semi-active cab suspension with multimode switching shock absorber

The aim of this work is to design a variable universe fuzzy control of a wheel loader semi-active cab suspension with damping multimode switching shock absorber. Considering the cost and reliability, a new type of shock absorber, whose adjustable damping characteristics are achieved by just changing the on–off statuses of two solenoid valves, is applied to the wheel loader cab suspension. The vibration model of the wheel loader, which considers the vibration characteristics of the working device, the four-wheel correlated random road excitation, and the engine vibration excitation simultaneously, is established first. Based on the working principle of the target shock absorber, the damping multi-state switching model is also established to reflect the relationship between the damping coefficients and the on–off statuses of two solenoid valves. Then, a variable universe fuzzy damping control strategy, which can determine the optimal switching sequences of the damping modes according to the cab suspension performance indexes, is designed. Finally, simulation analyses were conducted to verify the effectiveness of the proposed control approach of the wheel loader semi-active cab suspension with multimode switching shock absorber.

Simulation Analysis of Cab Mounting System of Flat-head Truck

Because the working environment of heavy truck with flat head is harsh, it is often in full load or vibration and impact load for a long time, and the cab suspension system receives these responses, and the driver’s intuitive feeling is the output response of the system. In this paper, the static and dynamic characteristics of air spring are tested, and the stiffness and motion characteristic curves are obtained. Then, according to the test data, the model of cab air mount system is established in ADAMS software, which simulates the response of cab mount under real vibration and evaluates its vibration reduction performance.

The Effect of Change in Assembly Sequence on Permanent Strain of Cab Suspension Console

The Effect of Change in Assembly Sequence on Permanent Strain of Cab Suspension Console

Calculated evaluation of the efficiency of dynamic vibration isolators of the tractor cab suspension system

The article gives a brief analysis of vibration-protective properties of standard rubber monoblock vibration isolators used in the systems of cabin suspension of domestic tracked tractors. The advantages of dynamic vibration dampers are described. The dynamic model of the tractor with standard and dynamic vibration isolators is described. The article presents the review of the methods of performed design researches and the analysis of their results.

Simulation of nonlinear vibration responses of cab system subject to suspension damper complete failure for trucks

The strong vibration responses of the cab system can be restrained by the damper force and the friction of the suspensions for trucks. After the failures of dampers, especially in the case of the complete failure, the anti vibration effect of the friction is prominent. However, the nonlinear vibration response characteristics of the cab subject to the damper complete failure have not been revealed. In order to reveal the nonlinear vibration response characteristics, a dynamic model of the cab system was established and its vibration equations were given. The friction forces existing in the suspensions were determined by the bench test. The influences of the friction forces on the cab vibration under different amplitude harmonic inputs were investigated when the dampers completely fail. The cab vertical displacement changes with the excitation amplitude and the vibration represents various motion states, including the periodic motion, the quasi-periodic motion, and the chaotic motion. The simulation results show that when the dampers fail, the proper friction forces help to suppress the quasi-periodic motion and the chaotic motion of the cab and to reduce the amplitude of the periodic motion. The proper friction forces can make the cab movement far away from the chaos area. They also help to avoid the fatigue damage of the cab floor and suspension parts to improve the service life of the suspension parts and to reduce the maintenance cost of the cab suspensions.

Evaluation of Tractor Ride Vibrations by Cab Suspension System

HighlightsTractor ride vibrations were evaluated under various conditions according to type of cab suspension.Ride vibrations were measured on flat and bumpy roads using four tractors with different cab suspension types.Tractors with hydro-pneumatic suspension exhibited smaller ride vibrations than tractors with rubber mounts.Semi-active hydro-pneumatic control resulted in smaller ride vibrations than those resulting from passive control.Abstract. In this study, tractor ride vibrations were evaluated under various conditions according to the type of cab suspension, and the effects of different cab support methods on these ride vibrations were determined. Ride vibrations on flat and bumpy roads were measured using four tractors equipped with different cab suspension types and were analyzed based on ISO Standard 2631-1 for human exposure to whole-body vibration. The ride vibration values were evaluated using the weighted root mean square acceleration and fourth-power vibration dose value. The results confirmed that the tractor equipped with semi-active hydro-pneumatic cab suspension at the two rear positions yielded smaller ride vibrations than the tractors with rubber mounts at all four positions. Vibration reduction effects of up to 53.8% and 67.1% were yielded in the flat road test and bumpy road test, respectively. In addition, among the two tractors with hydro-pneumatic cab suspension systems, ride vibrations were reduced by approximately 7.1% in the tractor that used semi-active control as compared to the tractor that used passive control. Keywords: Hydro-pneumatic cab suspension, Ride vibration, Rubber mount, Whole-body vibration.

An adjustable damper for cab suspension

An adjustable damper for cab suspension

Simulation and Optimization of Truck Cab Suspension System Based on ADAMS

Taking the suspension system of the truck cab as the research object, aiming at the three working conditions commonly used by engineering vehicles, cab suspension system dynamics model is established in ADAMS/view. The stiffness and damping of the front and rear suspension are design variables, and the maximum acceleration of the cab floor is minimized as the design objective. ADAMS’s own optimization module is used to optimize the suspension parameters, and the optimal matching value of the suspension parameters under the three working conditions is obtained. And On this basis, the three sets of values were optimized by DOE orthogonal test technology, and a set of optimal matching values of suspension parameters suitable for three kinds of road conditions was obtained. Finally, the accuracy of the model and the optimization value of cab suspension parameters are verified by the actual road test results.