Development of Anti-lock Brake System in Virtual Environment

emergency braking. Thus, how to select attachment coefficient and simulate road conditions are of critical significance in the construction of virtual environment. We adopt an algorithm [ I l l -[12]-simplification detail rendering of digital terrain model-to with the construct the threshold value of tilt angle and the real continuous level of terrain model with different attachment coefficient.
fuzzy controller and used software simulation to build
simulation block for the full ABS control system; Davis[2] reports an initial simulation-based study to determine the performance potential of controller designed with neural network method; Hold and Bhatt [3] have developed a self-testing ABS controller using CAD tools; Sergey [41 provides the control design via the sliding mode approach.
a
to monitor whethcr tail
slide happened, 3) simulate motions of vehicle when ABS is
I1 VIRTUAL REALITY PLATFORM MODEL
Virtual Reality is usually perceived as any in which users is effectively immersed in a responsive virtual world. [8] It is mainly composed of four crucial technologies: visual displays, graphics rendering system, tracking system and database construction and maintenance system. In this paper,
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control system; In scction N, we use virtual environment to obtain simulation results and apply them to real system. At the last section, we give the conclusions.
Fig.2 illustrates three key operations: 1) construct a 3-dismensional body of vehicle in virtual environment and 2) calculate the angle of deviation working. Deviation angle
B. Road conditions model
In rainy, icy or other low attachment coefficient road
conditions, traffic accidences are likely to happen when
6
TriNum<UAX?
Display the objecrs
Abslracl-W?th increase ofspeed, Vehicle5 brahe performance is o f
attracts a lot of researchers in this area. Most researchers focus on control algorithms and their feasibility analysis based on computer simulation. Chen [I] has developed a
it mainly includes vehicle model and road conditions model.
a is
a key parameter to monitor the
functions of ABS. When ABS is working, ideal value of
a is zero, which indicates that vehicle stops alone a direct
o f
based on virtual
environment, which is a generic solution to all kin& ojvehicles in
I INTRODUCTION
Since appearance of vehicle and improvement of its speed, vehicle’ brake performance is focused. According to some statistics, 25% of traffic accidents happened because of bad brake performance and low effective brake. Thus ABS is gradually accepted as standard equipment used in vehicles.
VEClMS 2004 - IEEE Intematianal Conferenceon V i m 1 Envimnments, Human-Computer Interfaces. and Measurement Systems Boston, MA, USA, 12-14 July 2004
Development of Anti-lock Brake System in Virtual Environment
1 -
Control Singals
I
Acquisition and
Annlysis
I
Fig.1. System architechre ofABS
ABS is a device that can prevent the lock-up of vehicle
wheels during emergency braking. It can keep good maneuverability when vehicle is turning, for the reason that the tire-road slip is controlled in an acceptable range. Also, vehicle loading ABS can obtain satisfactory braking distance and driving stability because of ABS’s regulation on brake pressure. With the popularity and commercial value, ABS In this paper, we intend to develop a generic solution to
critical importance to its safe and reliable operation. Conventional techniques used to the design and manufacturing ofAnri-loch Brake System (ABS), are based on real analysis and design. while, these techniques and contml algorithms are time-consuming, especially
functions, such as transformer, rendering, fog, anti aliasing, texture map, we can establish the body of vehicle and simulate its motion in virtual environment with a natural undulating terrain [9] under different road conditions. Here presents the algorithm.
line when emergency braking. As shown in Fig.3, included angle of
X,
a is
--axis
in
coordinate system
(x,, y , ,z ) and x, --axis in coordinate system ( x,, y , ,z ~ ) . ,
I n i t i a l i z e 30 Objects
x = f( t ) and z = g ( t )
Then at the time of
t,,
Vehielm mows
two dimensional n r o j e c t i o n s of
J
Fig.3.Coordinate System in Vimal Environment
ABS design based on the combination of virtual environment and real testing and manufacturing, as shown in Fig.1. In section I1 , we provide the software and hardware models of virtual environment, which includes vehicle model and road conditions model; In section III, we develop a full ABS
not always compatible with other hinds o vehicles. This paper f
presents a new method o design and pmtorype mali-ation f Vehicle Dynamics Control System-ABS real design and manufacturing. Keywords-Anti-lock Broke System, Krtual Reality, Terrain Mode, OpenGL
Dengfeng Yang, Zhihua Feng, Desheng Ma, Gang Sun
Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui, China, 230027 Phone:86-55 1-3607894. Fax:86-55 1-3607894, Email:ydf@mail.ustc.edu.cn
Suppoቤተ መጻሕፍቲ ባይዱing the vehicle is moving forward, the equation of motion locus can be expressed as:
A. Vehicle Body and Motion Model
By using sofware--OpenGL, 3DMAX, and their