Shu Wen Zhou

Jackknife Control on Tractor Semi-Trailer during Emergency Braking

Emergency braking on a low coefficient of friction or split-mu road surface, the semi-trailer may push the tractor from behind until it spins round and faces backwards, and a jackknife accident occurs. In this paper, the tractor semi-trailer kinematics was analyzed and a 3-dof of tractor semi-trailer model was used to design a state observer to estimate the articulation angle. To avoid a jackknife, the four-channel ABS which can produce maximum braking force will be switch to three-channel ABS according the estimated articulation angle. The virtual prototyping simulation results show that the jackknife control system can improve the tractor semi-trailer lateral stability under emergency braking and shorten the stop distance dramatically on split-mu road surface at high speed.

Stability Control on Tractor Semi-Trailer during Split-Mu Braking

Handling behaviour of articulated vehicles combination is more complex and less predictable than that of non-articulated vehicles. It is usually difficult for drivers to maneuver a tractor semi-trailer during high speed emergency braking on split-mu road surface. Braking on this type of road surface, the conventional anti-lock braking systems will cause the vehicle deviate from the desired direction, or overmuch stopping distance. In this paper, a 3-dof of tractor semi-trailer model was used to produce desired yaw rates which were compared with actual yaw rates. An active front steering control and four-channel ABS were integrated to improve the tractor semi-trailer lateral stability while braking on split-mu road surface, which will produce maximum braking force. A full function tractor semi-trailer model was built and assembled in multi-body dynamics software, and the dynamic analysis was performed on split-mu road surface. The simulation results show that the integrated system can improve the tractor semi-trailer lateral stability under braking on split-mu road surface.

Vehicle Dynamics Control for Tractor Semitrailer Lateral Stability

Rollover and jack-knifing of tractor semitrailer on high speed obstacle avoidance under emergency are serious threats for motorists. A tractor semitrailer model was built with multi-rigid-body method in this paper. The steering performance of tractor semitrailer has been analyzed, as well as the stability control theory, including yaw rate following, anti-rollover. The dynamics simulation for yaw rate following and anti-rollover has been performed on the dynamic tractor semitrailer. The results show that the vehicle dynamics control proposed in this paper can stabilize the tractor semitrailer, rollover and jack-knifing are prevented and the tractor semitrailer more accurately follows the drivers desired path.

Study on Automatic Planning of Truck-Mounted Concrete Boom Pump System

In many cases, pouring concrete automatically instead of manually will lessen the operator’s labor intensity and increase productivity dramatically. An automatic pouring system was schemed in this paper, as well as the planning of pouring trajectory. A simulation model was built based on virtual prototyping, and the impact of new automatic pouring system on the boom system was verified with the co-simulation method. Since the complexity of the work environment, the obstacle avoidance of boom system was analyzed and planned. A 3D program based on virtual reality technology was built to simulate the automatic pouring process.

Structural-Acoustic Analysis of Automobile Passenger Compartment

Besides the performances of handling, stability, ride comfort, power and fuel economy, the sound pressure levels in the automobile passenger compartments heavily influence the customer’s purchasing decision. The interior acoustics of automobile passenger compartment was analyzed in this paper. The frequency response analysis was performed on the vehicle body due to road roughness. The frequency response of vehicle body’s output spectrum, nodes’ velocity is used as the boundary condition of the acoustic cavity. With boundary element method and acoustic transfer vector method, the panel acoustic contribution was analyzed. By modifying the stiffness, damping or mass of the corresponding panel, the acoustic pressure levels at the driver’s and passenger’s ear were decreased.

Study on Vehicle Stability Control Based on Yaw Following and 4WS

Because of the high speed and insufficient stopping distance, a sudden obstacle will force the vehicle to perform a lane change maneuver to avoid a crash or rear-end collision. A vehicle yaw following control system was designed in this paper to prevent vehicles from spinning and drifting out on high speed obstacle avoidance under emergency. However, yaw following control system, in some situation, may not react properly to, or even deteriorate on-road rollover events. Four-wheel steering control system can reduce the excessive yaw movement due to yaw following control system. An integration control system, including yaw following control system and four-wheel steering control system was presented and discussed. With this improved control system, the vehicle lateral stability can be improved on high speed obstacle avoidance.

Dynamic Mechanical Analysis of Automotive Gearbox Casing

After the three-dimensional solid modeling of the SG135 automobile gearbox, finite element analysis models of static, transient and harmonic response load are built based on correlation theory. On the basis of ADAMS dynamic simulation of different gearbox gears, transient load of the gearbox casing at different working gears is found out. With frequency response characteristic of gearbox casing analyzed at typical working conditions of first gear and reverse gear, the evaluation of some factors such as strength and stiffness are given out, which provides theory basis for further improvement of gearbox casing structure and strengthening weak links. Based on harmonic response analysis, the impact on gearbox casing structural vibration by harmonic excitation of the engine is imitated, and the match relation of frequency response between the gearbox and the engine is analyzed. Improvements about engine operational limits matching and gearbox structural design are proposed.

Study on High-Speed Lateral Stability of Car-Trailer Combination

Since the handling behaviour of car-trailer combination is more complex and less predictable than that of non-articulated vehicles, the drivers may lose control of the vehicle in some hasty steering maneuvers. The kinematics of car-trailer combination has been analyzed with a 3 DOF model. A modified Vehicle Dynamics Control system was designed to improve the lateral stability of the trailer. The dynamics simulation for lateral stability of car-trailer combination has been performed on the multi-body model. The results show that the lateral stability of car-trailer combination, including yaw rate and roll angle has been improved with the modified Vehicle Dynamics Control system.

Lateral Stability Control Design for Tractor Semitrailer Based on Virtual Prototyping

Tractor semitrailers on high speed obstacle avoidance under emergency are likely to arise rollover or jack-knifing, which are serious risks for motorists. A dynamic stability analysis model of a three-axle tractor semitrailer vehicle is developed using the application tool. The linearized vehicle model is utilized to predict the dynamics state of the tractor semitrailer built in multibody dynamics simulation software. The lateral stability simulation for yaw rate following and anti-rollover has been performed on the dynamic model based on virtual prototyping. The results show that the lateral stability control based on tractor semitrailer proposed in this paper can stabilize the tractor semitrailer, rollover and jack-knifing can be prevented to a large extent.

Study on Semi-Active Control for Leaf Spring Suspension Based on Virtual Prototyping

Conventional leaf spring suspension in heavy duty trucks can afford large carry capacity and better handling stability ability but less ride performance. In this paper a semi-active control was embed to the leaf spring suspension. The dynamics model of semi-active leaf spring suspension was built and analyzed. A full function heavy duty tractor using virtual prototyping was built and assembled in dynamics simulation software. A bumpy road test was performed to verify the performance of the proposed semi-active suspension. The results show that the semi-active leaf spring suspension proposed in this paper can improve the ride performance of the heavy duty trucks. The occupants in the vehicle cab will feel more comfortable.