Nenggen Ding

Sensor systems for vehicle environment perception in a highway intelligent space system

A Highway Intelligent Space System (HISS) is proposed to study vehicle environment perception in this paper. The nature of HISS is that a space sensors system using laser, ultrasonic or radar sensors are installed in a highway environment and communication technology is used to realize the information exchange between the HISS server and vehicles, which provides vehicles with the surrounding road information. Considering the high-speed feature of vehicles on highways, when vehicles will be passing a road ahead that is prone to accidents, the vehicle driving state should be predicted to ensure drivers have road environment perception information in advance, thereby ensuring vehicle driving safety and stability. In order to verify the accuracy and feasibility of the HISS, a traditional vehicle-mounted sensor system for environment perception is used to obtain the relative driving state. Furthermore, an inter-vehicle dynamics model is built and model predictive control approach is used to predict the driving state in the following period. Finally, the simulation results shows that using the HISS for environment perception can arrive at the same results detected by a traditional vehicle-mounted sensors system. Meanwhile, we can further draw the conclusion that using HISS to realize vehicle environment perception can ensure system stability, thereby demonstrating the methods feasibility.

Integrated control of automobile ABS/DYC/AFS for improving braking performance and stability

Braking control on a μ-split road is not an easy task. An integrated control (ITC) algorithm is proposed by combining antilock braking system (ABS), direct yaw-moment control (DYC) and active front steering (AFS). The algorithm is intended for maximising the utilisation of road friction while maintaining directional stability of a vehicle during emergency braking on a μ-split road. A three-layer hierarchical control architecture is developed for the ITC. The upper-layer controller is used for DYC to generate a desired yaw moment, allocation of the moment to ABS and AFS is handled by the intermediate-layer controller, and two control algorithms are designed at the lower-layer for ABS and AFS, respectively. The performance of the ITC is compared with a modified independent control (MIC) algorithm via hardware-in-the-loop (HIL) simulations. The results show that the braking performance and stability of the vehicle are improved by employing the ITC algorithm.

An integrated algorithm for vehicle stability improvement with the coordination of direct yaw moment and four-wheel steering control

This paper presents an integrated algorithm for enhancing vehicle stability with the coordination of four-wheel steering and direct yaw moment control based on a hierarchical control structure. At the upper level of the integrated control system, the desired four-wheel steering angles and yaw moment are derived using a sliding mode control technique; at the lower level, the control inputs are optimised and implemented using a pseudo-inverse method. A 2 degrees of freedom (DOF) vehicle model is generated to design the integrated control algorithm, and an 8-DOF non-linear vehicle model is developed for numerical simulations. The algorithm is evaluated using a hardware-in-the-loop real-time simulation system (HILS) with the physical implementation of active four-wheel steering and differential braking. It is demonstrated that the proposed algorithm can enhance vehicle handling and stability under different operating conditions.

Concept Design for Sliding Boot of Submerging-Floating Moving Platform Based on Compliant Mechanism

The traction force of walking device on normal pavement is determined by contact pressure and adhesion force related with road friction coefficient. Soft terrains should be sufficiently carrying-capable for walking devices to keep their trafficability and not sink into the surface. Deep soft terrains without bottom carrying layer, such as swamps, tidal flats, and paddy fields with deep layer of silt, are unable to provide sufficient load-bearing capacity for vehicles and walking devices. Aiming at solving above problem, a noval surmerging-floating moving platform is proposed. As one role of running gear, a skidding defined as “sliding boot” is designed. The sliding boot is a fixture clamped on the front wheel as a plier, when vehicle is running on invertebrate terrains. Due to dynamic characteristic of sliding boot, sliding boot is ultized as “floating” unit. In order to essure the reliability and safty of sliding boot, mechanism design is completed based on compliance of pneumatic tire. The design method is verified by test. The results show the design method of sliding boot is approved reasonable, feasible and practical.© 2013 ASME

Design and Structure Analysis of Wheeled Chassis With Self-Balancing Rocker of Rescue Engineering Machinery

A wheeled chassis with self-balancing rocker is developed for rescue engineering machinery. This chassis has better ground adaptability compared with traditional ones because of the automatically adjustable ground clearance and body posture, non-trapezium steering mechanism, independent four-wheel steering, and “X”-type radiation legs.Finite element analysis on the chassis structure is done with two mechanical models and under typical finite element working conditions. HyperWorks software is used to analyze different parts of the chassis, and the results are used for structure optimization. The rocker plate thickness and rocker frame topology are optimized using Optistruct. The results demonstrate the effectiveness and feasibility of proposed optimization methods.Copyright

Development and Analysis of Hilly Power Chassis With Vari-Ground Clearance and Vari-Wheel Track Mechanism

A kind of Hilly Power Chassis with Vari-ground Clearance and Vari-wheel Track Mechanism (VII-HPC) is designed to be adapted to various types of crops grown ridge section and height. It consists of the middle part, balancing system, two driving axles and steering system. These assemblies form an H-type chassis structure where both sides of the driving axle and the middle part are connected for power transmission, ground clearance varying and wheel track adjustable function, which ensures full-time four-wheel drive in a complex road environment and confirms that the middle part is always in the angle bisector of the two driving axles. According to the various agricultural ground clearance and line spacing of different crops in the hilly areas, the ground clearance and the wheel track can be adjusted continuously and smoothly driven by hydraulic system. According to VII-HPC Structural Characteristic without Ackerman Steering Linkage, the hydraulic four wheel steering scheme has been proposed. The related analysis is presented to verify the feasibility of VII-HPC, including the relationship between the ground clearance and parameters like centroid height, and the ride analysis at different speeds on the pulse road. The results and the subsequent experimental results show the design method and the concept of VII-HPC are proved reasonable, feasible and practical.© 2013 ASME