Tractor Semitrailer Research Articles

Ride Comfort Analysis of Unsuspended Cabin Tractor Semi-Trailer

This research work uses parameter variation techniques for calculating the set of vehicle parameters that result in the best ride comfort for the driver. Tractor semi-trailer vertical dynamic ride model is developed using 9 degrees-of-freedom. The simulation of the model is conducted using MATLAB. The input to the system is a velocity amplitude function of the vertical road irregularities. Other inputs include the load conditions, vehicle speed and road conditions. The RMS vertical weighted acceleration at the driver’s seat and at the centre of gravity of tractor and semi-trailer for different parameters of the vehicle are assessed for ride comfort analysis.

Liquid Sloshing Effect Analysis on Lateral Dynamics of an Articulated Vehicle Carrying Liquid for Various Filled Volumes

In this paper, the consequences of filled volume on the transient lateral dynamic and stabilities boundaries displacement of an articulated vehicle carrying liquid is investigated. First, a sixteen-degrees-of-freedom nonlinear dynamic model of an articulated vehicle is developed. Then, the model is validated by using TruckSim software. Next, the dynamic interaction of the fluid cargo with the vehicle, by integrating a quasi-dynamic slosh model with a tractor semitrailer model is investigated. In this study, the most important dynamic reposes are considered which include yaw rate, roll angle and lateral acceleration for both the tractor and semitrailer as well as liquid center of mass lateral movement. Also, to investigate the rollover stability of the vehicle, lateral load transfer ratio is considered as an important factor. The dynamic system performance for three different filled volumes is exhibited in j-turn and lane change standard maneuvers. The simulation results revealed that by increasing the liquid volume the rollover probability rises due to the increase in roll angle and lateral load transfer, especially in lane change maneuver.

Fuzzy Logic Based Control of the Lateral Stability of Tractor Semitrailer Vehicle

A novel control scheme is proposed to improve the yaw stability of a tractor semitrailer vehicle in critical situations. The control scheme is a two-layer structure consisting of an upper yaw moment controller and a lower brake force distributor. The tractor and the trailer are, respectively, stabilized by two independent fuzzy logic based yaw moment controllers. The controllers for the tractor and the trailer are, respectively, designed to track the reference yaw rate of the tractor and the hitch angle between the tractor and the trailer while considering the variation of the hitch angular rate at the same time. The corrective yaw moments determined by the corresponding upper fuzzy yaw moment controllers are realized by active wheel braking. The performance of the proposed control scheme is evaluated by simulations on a nonlinear vehicle model. The results demonstrate that the proposed control scheme is robust and effective in stabilizing the severe instabilities such as jackknife and trailer oscillation in the chosen simulation scenarios. It is believed that this control scheme is robust to the variation of road adhesion conditions.

Analysis of bifurcation and stability for a tractor semi-trailer in planar motion

This paper is intended for bifurcation analysis of a nonlinear tractor semi-trailer vehicle model in planar motion and for investigating its stability under constant running conditions. Bifurcation analysis shows that bifurcation diagrams of a tractor semi-trailer are quite different from those of a single-unit vehicle. Some instability phenomena of the vehicle system such as jackknifing, sideslip, and spinning are explained by correlating them with the behaviour in the neighbourhood of unstable fixed points based on analysis of eigenvectors, phase trajectories, and status of lateral tyre force saturation. It is also found that yaw planar instability of a tractor semi-trailer is caused by lateral tyre force saturation of the tractor's rear axles and/or the trailer's axles. Moreover, the stability region in the state space is demarcated, and a stability index for evaluating size of the stability region in a feasible domain is proposed. Yaw stability under constant driving conditions is analysed by using the proposed stability index.

Study on Tractor Semi-Trailer Roll Stability Control

The rollover accidents in the tractor semi-trailer are often fatal and many factors could cause the tractor semi-trailer rollover. In this paper, a rollover prevention control method was proposed based on real-time calculation of rollover index. The vehicle Center of Gravity (CG) height from the ground is an important parameter in the rollover index and it is estimated through lateral acceleration sensor and suspension deflection sensors. Comparing the rollover index with the preset threshold, the differential braking will be applied to corresponding wheels once the trigger conditions are met. A roll stability control simulation was performed on the dynamic model based on virtual prototyping. The results show that the rollover prevention control proposed in this paper can stabilize the tractor semi-trailer and prevent from rollover on high speed curve driving.

The dependence of truck roll stability on size and weight variables

The roll stability of heavy–duty trucks and truck combinations is discussed both on the level of the fundamental mechanics of vehicle response and from the viewpoint of the quantitative influence of size and weight variables. The presentation on fundamentals begins with the case of a rigidly suspended vehicle and builds up to the case of a tractor–semitrailer with distinctive suspension stiffnesses and spring lash properties at the various axle positions. Size and weight considerations cover variations in axle load, gross weight and overall width as well as incidental issues involving the height and possible lateral offset of the payload centre of gravity.

The self–steering behaviour of a tractor–semi–trailer at high–speed and its control to improve lateral stability

The loss of stability by heavy highway tractor–semi–trailers can lead to serious traffic accidents. Among the contributing factors are variations in the operating conditions (e.g. different loading conditions, gusting side winds, and slippery patches on the road surface) which cannot entirely be controlled by the driver. In this paper, the behaviour of a 3–axle tractor–semi–trailer is examined from the point of view of steerability and a suitable measure of its handling characteristic is defined. On the basis of the results of this examination, some possible control methods are developed to improve the lateral stability of the tractor–semi–trailer using controlled steering of the tractor's rear wheels and of the trailer's wheels. The controller is designed using the virtual model following control law, and in the feedback loop both linear quadratic regulator (LQR) and H∞ controllers are applied.

Nonlinear ride analysis of heavy vehicle using local equivalent linearization technique

A multi–degree–of–freedom ride model of a typical tractor–semitrailer configuration comprising of nonlinear suspension damping mechanisms is developed. A local equivalent linearisation technique based on energy balance is employed to obtain the ride response of the nonlinear vehicle model. The critical behaviour of vehicle suspension(s) lock–up due to high magnitude of Coulomb (dry) friction is modelled and incorporated in the analytical technique such that the nonlinear behaviour of the system can be effectively simulated by the equivalent linear system. The effectiveness of local equivalent linearisation technique is demonstrated by comparing it with respect to conventional numerical integration and statistical linearisation techniques. A comprehensive parametric study is performed to investigate the influence of vehicle suspension characteristics, vehicle geometry, speed, highway profile and trailer loading patterns.

Heavy Truck Driver Workload Investigation

ABSTRACT Driver workload is of growing interest in the automotive society, since the number of in-vehicle technologies and vehicles on the road grows. Operational and environmental factors impact the driver's ability to negotiate a chosen course and place heavy demands on the driver in terms of mental and physical capacity. A key component of the driver's operating environment is the vehicle. In this research, the impact of various tire configurations, for example, dual and wide based, for a Class 8 tractor–semitrailer combination vehicle on driver workload performance is presented. Driver workload performance is assessed during four maneuvers: 60 m radius steady state circle, 120 m radius steady state circle, road course, and North Atlantic Treaty Organization emergency lane change maneuver. Surface electromyography (sEMG) electrodes were placed on the left and right wrist flexors (flexor carpi ulnaris) and right wrist extensors (extensor carpi ulnaris) in order to capture muscle activity during all maneuvers. Peak and integrated values of sEMG are calculated to obtain metrics of driver workload. Results of the study show distinct separation of muscle activity for each tire configuration. Differences in driving techniques were also identified based on the dominant hand of the driver and orientation of the maneuver, that is, clockwise or counterclockwise.

An improvement in rollover detection of articulated vehicles using the grey system theory

A Rollover Index combined with the grey system theory, called a Grey Rollover Index (GRI), is proposed to assess the rollover threat for articulated vehicles with a tractor–semitrailer combination. This index can predict future trends of vehicle dynamics based on current vehicle motion; thus, it is suitable for vehicle-rollover detection. Two difficulties are encountered when applying the GRI for rollover detection. The first difficulty is effectively predicting the rollover threat of the vehicles, and the second difficulty is achieving a definite definition of the real rollover timing of a vehicle. The following methods are used to resolve these problems. First, a nonlinear mathematical model is constructed to accurately describe the vehicle dynamics of articulated vehicles. This model is combined with the GRI to predict rollover propensity. Finally, TruckSim™ software is used to determine the real rollover timing and facilitate the accurate supply of information to the rollover detection system through the GRI. This index is used to verify the simulation based on the common manoeuvres that cause rollover accidents to reduce the occurrence of false signals and effectively increase the efficiency of the rollover detection system.

Soft Measurement Technology for Tractor-Semi Trailer

A three degree of freedom vehicle dynamic model of a tractor semi trailer is established and a simulation mode is set up with the Matlab/simulink software. Then, design a Kalman state estimator, using easily measured parameters to estimate the tractor side slip angle, trailer yaw rate those are difficult measured or measuring in high cost; the simulation show that: the estimated value coming from estimator agree well with the simulation measurements, and can improve the estimation accuracy by adjusting the process noise covariance matrix and measurement noise covariance matrix.

The Selection of Process Noise Covariance Q and Measurement Noise Covariance R on Kalman Filter

At first, a seven degree of freedom dynamic model of tractor semi-trailer was established, and a simulation model with the Matlab/Simulink software was established too. Based on the model, a state estimator based on Kalman theory was designed, using easily measured parameters to estimate the parameters that are difficultly measured or have high measurement cost, after that, compared estimated values and simulation measurements and analyzed the influence with changes of process noise covariance Q and measurement noise covariance R.

A sliding-mode controller for directional control of articulated heavy vehicles

In order to improve the handling and stability of a tractor–semitrailer, a new sliding-mode controller is designed on the basis of a non-linear three-degree-of-freedom model of the vehicle. Three state variables, namely the tractor’s yaw rate, the tractor’s lateral velocity and the articulation angle, are controlled as the target responses using active steering. A new version of the desired articulation angle is proposed so that the rear end of the semitrailer unit is forced to follow the path of the fifth wheel if the proposed reference value is tracked. A 12-degree-of-freedom non-linear model of the articulated heavy vehicle validated by real test data is used to evaluate the control system. The comparative simulation results prove the significant effects of the proposed non-linear control method with respect to a previously designed linear controller on improving the handling and stability performance, especially under severe driving conditions.

Control Dominant Factors Analysis for Under-Actuated Vehicle Platoon Stability System

As a kind of flexible and under actuated systems which based on cooperative vehicle infrastructure system (CVIS), autonomous tractor-semi trailer platoon in vehicle networking can enhance the information interaction and controllability of safety. Establish the two degree of freedom model of tractor-semi trailer firstly. Then, we analysis dominant factor and equilibrium point for the under actuated physics system's stability including its coordination evolution rule. Space-time mathematical model was established based on the dynamic observation information during vehicle platoon driving. μ-Synthesis robust controller was designed to deal with real time conditions, for example, following, lane changing and obstacles avoiding. The parameters of autonomous under actuated platoon controller can be adjusted on-line by fuzzy rules. Finally, we verify robust stability and dynamic performance of autonomous under actuated platoon tracking controller by the computation simulation method.

Kinematic and dynamic analysis of a heavy truck with individual front suspension

The main focus of this work is on the characteristics of a commercial vehicle with individual front suspension (IFS). Both kinematic and dynamic properties of the vehicle are investigated through simulations and analytical expressions. Moreover, employing the model of the tractor semitrailer combination, the study presents the results of comparison between the trucks with IFS and rigid front axle with respect to comfort and handling. This is done by analysing the responses of the vehicles to different road and steering inputs. The obtained results show enhanced comfort and steering feeling for the truck with IFS.

Study on Lateral Stability Control for Tractor Semi-trailer Based on Sliding Mode Control

Study on Lateral Stability Control for Tractor Semi-trailer Based on Sliding Mode Control

A Gain-Scheduled PID Controller for Automatic Path Following of a Tractor Semi-Trailer

A Gain-Scheduled PID Controller for Automatic Path Following of a Tractor Semi-Trailer

Assessing the Effect of Chassis Torsional Stiffness on Tractor Semi-trailer Rollover

The semi-trailer chassis was usually treated as rigid body in many existing literature, which would lead to larger deviation from actual situation. A rigid semi-trailer chassis model was built andflexiblized based on the modal test results in this paper. The tractor semi-trailer withflexible chassis was utilized to simulate the rollover scenarios on high speed obstacle avoidance under emergency based on virtual prototyping. The simulation results were compared to the simplified 5-DOF, 3-wheel linear vehicle model. It was revealed that the wheels on flexible chassis are more inclined to be got pushed up and away from the road, which is likely to occur rollover. The actual roll angle of semi-trailer is proposed to be measured from several positions, and it should be a weighted value.

Influence of Road Surfaces on Whole Body Vibration for Suspended Cabin Tractor Semitrailer Drivers

This paper presents a study on whole body vibration analysis for drivers of tractor semitrailers. The tractor semitrailer, namely, a suspended cabin tractor semitrailer was considered for the present investigation. The important process parameters such as different speeds, different road surfaces and different loaded conditions with driver seat interface acceleration in X- longitudinal, Y-transverse and Z-vertical axes were tested. The average running weighted root mean square accelerations obtained after conducting the experimental work were between 0.6265 and 1.5594 m/s2at the driver seat interface in the translational axes. Based on the weighted acceleration the value was compared to ISO 2631–1:1997 to find the permitted exposure time of drivers. The acceleration suspended cabin tractor semi trailer drivers are exposed to exceeds the upper exposure limit for an 8-h work day as outlined in (ISO 2631–1:1997) [1] when they work continuously.

Multi-objective stability control algorithm of heavy tractor semi-trailer based on differential braking

Rollover and jack-knifing of tractor semi-trailer are serious threats for vehicle safety, and accordingly active safety technologies have been widely used to reduce or prevent the occurrence of such accidents. However, currently tractor semi-trailer stability control is generally only a single hazardous condition (rollover or jack-knifing) control, it is difficult to ensure the vehicle comprehensive stability of various dangerous conditions. The main objective of this study is to introduce a multi-objective stability control algorithm which can improve the vehicle stability of a tractor semi-trailer by using differential braking. A vehicle controller is designed to minimize the likelihood of rollover and jack-knifing. First a linear vehicle model of tractor semi-trailer is constructed. Then an optimal yaw control for tractor using differential braking is applied to minimize the yaw rate and lateral acceleration deviation of tractor, as well as the hitch articulation angle of tractor semi-trailer, so as to improve the vehicle stability. Second a braking scheme and variable structure control with sliding mode control are introduced in order to achieve the best braking effect. Last Fishhook maneuver is introduced to the active safety simulation and the active control system effect verification. The simulation results show that multi-objective stability control algorithm of semi-trailer could improve the vehicle stability significantly during the transient maneuvers. The proposed multi-objective stability control algorithm is effective to prevent the vehicle rollover and jackknifing.