Papers by Author: Si Qi Zhang

Abstract: In this paper, under various constraints, based on LR series engine of automobile mixed model assembly line as an example, application of MMALB theory design automobile engine assembly line. To solve the multi-objective optimization problem, we establish the mathematical model between the workstation and workstation internal load balancing two optimization objectives. And engine assembly line is dynamic simulated by using the simulation software eM-Plant. The results verify the validity and practicability of the digital simulation. Finally, the planning scheme guarantees the whole assembly line load balancing and achieves production requirements.

Abstract: A three-dimensional multi-body model of the 50th percentile male human and discretized neck was built to evaluate the effect of active head restraint on cervical vertebrae injuries lessening in vehicle rear impact. The discretized neck includes of cervical spine vertebrae, intervertebral discs, ligaments, and muscles. The BioRID-II adult male dummy restrained using safety belt was seated on a sled, whose longitudinal velocity measured from rear impact FEM simulation was applied to simulate the relative motion of the head and neck. According to the interspinous ligament loads and the ligamenta flava loads of the cervical spine, an active head restraint and an impact absorber were designed to lessening the neck injuries in vehicle rear end collisions.

Abstract: 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.

Abstract: 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.

Abstract: The human spinal column is a highly complex and sophisticated system both from an engineering and neurological point of view, and provides a source of biomimetic inspiration for analysis of its function in trauma scenarios. A three-dimensional multi-body model of the 50th percentile male human and discretized neck were built for the study on cervical spine injuries in vehicle frontal impact. The discretized neck includes of cervical spine vertebrae, intervertebral discs, ligaments, and muscles. Following motor front crash evaluations, a finite element vehicle model was propelled straight ahead into a concrete barrier at a speed of 50 km/h. The longitudinal velocity of driver seat was decreased due to the absorbing energy function of the crumple zones. A Hybrid III adult male dummy was seated on a sled, restrained using safety belt, and longitudinal velocity measured from frontal impact was applied to simulate cervical spine injuries. The disk bending loads, interspinous ligament loads and disk shear strain of the cervical spine were analyzed in this paper.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The paper presents a vehicle dynamics control strategy devoted to prevent vehicles from spinning and drifting out. With vehicle dynamics control system, counter braking are applied at individual wheels as needed to generate an additional yaw moment until steering control and vehicle stability were regained. The Linear Quadratic Regulator (LQR) theory was designed to produce demanded yaw moment according to the error between the measured yaw rate and desired yaw rate. The results indicate the proposed system can significantly improve vehicle stability for active safety.

Abstract: 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 driver's desired path.