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DESIGN AND CONTROL OF THE 4WD SYSTEM AND 8WS SYSTEM OF AUTOMOBILE FOR TRANSPORTING BRIFGE Li Yunhua , Zhang Zhihua and Wang Zhanlin Institute of Mechatronic Control, Beijing University of Aeronautics and Astronautics, Beijing, P.R. China Tel/Fax: 010-82316053, E-mail: [email protected] Zhengzhou Dafang Bridge-Machine CO. LTD, Zhengzhou, P.R. China Tel/Fax:0371-8883328, E-mail:[email protected]

ABSTRACT Aiming at the requirement of 4WD(4 Wheels Drive) system and 8WS(8 Wheels Steering) system of the automobile, the mathematical model, design of the controller, and engineering realization of controller based on CAN(Controller Aerial Network) bus are studied. The method of control and management, and electronic operating panel (interface between driver and main controller) are proposed. The theory of control and synthesize for the MIMO control system with one dimension reference input and n-1 dimension ratio inputs is put forward. The conclusion here founded the theoretical foundation of the hydraulic control system of the engineering transporting truck. Key Words: hydraulic control, automobile, computer control, field bus control systems, controller aerial network

INTRODUCTION With the automation level, operating complexity, and electrohydraulic control components of the automobile on the increase, the control and management to its mechatronic subsystem has become an imperative problem. Because of field bus is of good operating property and opening property, saving on link cable, hardware cost and field assembling cost, an electrohydraulic control system of automobile realized by FCS(Field Bus Control System) has been noticed greatly. CAN is controller aerial network, it is a type of two-way serial communication network based bus. It is of the physical layer and data information link layer based on OSI(open systems interconnection) model. CAN bus is

originally designed for the detection and control of automobile by Germany Bosch Corporation. Because of its excellent performance, high reliability, and unique design, the famous automobile manufacture corporations, for example BENZ, BMW, ROLLSROYCE, etc., use CAN bus to realize the data communication between the automobile control system and the each of detection component and actuator. In this paper, aiming the requirement of the truck for transporting the box-beam of the bridge, a kind of the microcomputer control systems based on CAN-FCS and electrohydraulic control is proposed. This system is called the microelectronic system of the truck for transporting bridge. It has three sub-systems, i.e., traveling system, steering system, and horizontal adjusting system, and two control units of monitor, display, and operation which is separately laid in the cabin to be set in the front end and the rear end of the truck for transporting bridge. The traveling system has 4 driving sub-trucks, 4 follower sub-trucks, 8 electrohydraulic proportional variable displacement driving motors and 2 electrohydraulic proportional variable displacement pumps. The steering system is belong to independent type system, it is consist of 8 electrohydraulic power steering mechanism. The horizontal adjusting system has 8 supporting cylinders, it can work in the 3 supporting points manner and 4 supporting points manner according to requirement. Three systems above being mentioned can be all controlled and managed by center operating unit through CAN bus. The truck for transporting bridge and the arrangement of control system is shown in Fig. 1.

Fig. 1 Scheme of the truck for transporting bridge This paper is arranged as follows: part 1 is a summary introduction and basic description of the truck for transporting bridge, part 2 describes the general design of CAN-FCS, part 3 is the control scheme design of the travelling system, part 4 is the design of control scheme

of the independent steering system, part 5 is the design of the control scheme of the horizontal adjusting system, part 6 is the design of the control law when the truck for transporting bridge is under the steer operation, and the end is the conclusion of the paper.

DESIGN OF FCS OF THE TRUCK FOR TRANSPORTING BRIDGE The FCS of the truck for transporting bridge is shown in Fig. 2.

CAN-BUS

CAN-AO

AMP

CAN-AI

sensor

CAN-AO

AMP

variable motor 1

rpm

control panel

display

speed lever

CAN-AI

rpm sensor

travel unit

airborne PC

pump solenoid CAN-DO

steer disk

variable motor 8

CAN-DO

operating unit CAN-AI

valve

motot solenoid valve main pump pressure

steer pump pressure

suspension horizontal adjusting cylinder

horizontal meter

pressure tranducer

CAN-ADJ

AMP

CAN-AO

steer motor£±

angle sensor CAN-AI

CAN-ADJ

AMP

CAN-AI

steer motor£¸

angle sensor

engin speed

CAN-AI

steer disk

steering unit

angle

CAN-AI CAN-DO

cooling solenoid valve

Fig. 2 Scheme diagram of FCS of the truck for transporting bridge can be locked each other. The FCS of the truck for transporting bridge has two (2) Human Interface realization modes. Scheme 1 is the realization mode based on airborne industrial control computer and RSMThe excellent operating performance is one of the CAN. Scheme 2 is the realization mode based on the important indexes to evaluating the performance of CAN intelligent node and CAN-I/O node. Among of automobile. In this truck, it has many kinds of motion, them, scheme 1 is of the short developing period and e.g., direct traveling, inclined traveling, center steering, high reliability, but its cost is high. Scheme 2 needs to front bridge and rear bridge steering, low speed design interface circuit card using CAN device and to traveling, high speed traveling speed traveling, fine develop software according to CAN communication slow traveling, etc., and the operating of the agreement, but its cost is low and its technical electrohydraulic control system needs to set many input maintaining secrecy is good. Here the scheme 1 is used. parameters, for example, vehicle speed, steering speed, The connection of FCS of the truck for transporting steering radius, inclined angle, and so on. So to design a bridge is shown in Fig. 2. It consists of 4 sections, i.e., human interface for finishing the connection between operating section, traveling control section, steering driver and the central controller of electrohydraulic control section, and horizontal adjusting section. Among control system is very essential. of them, the operating section has two set of unit with The human interface is shown in Fig. 3. It consists of same function, they are respectively set in the cabins to many buttons, speed adjusting handle, operating wheel, be posited at the front end and rear end, and two units and so on.

(1) General Design

low speed

centre steer

high speed

FW steer

H-axis steer

jogging

RW steer

V-axis steer

angle march

condition monitor

speed adjusting lever back set

operating wheel

Fig. 3 Human Interface(Electronic operating panel)

CONTROL SCHEME TRAVELING SYSTEM

DESIGN

OF

Traveling system has 4 driving sub-cars and 4 flower Single loop motor rotational speed control system has two modes. Mode 1 is the common parallel mode. Mode 2 is the parallel mode to be based on second adjusting

sub-cars. Each sub-car has two driving motor, and high speed driving speed project is used. Its construction and operation principle are shown in Fig. 4. principle. They are respectively shown in Fig. 5 and Fig. 6. Among of them, mode 2 is of good performance, and simple realization construction of the controller.

status of road

traveling parameters

rpm-sensor

single loop controller

determine order rotional speed

CAN bus

Fig. 4 Block Diagram of Traveling Control System

Vm

Qi

PL

1 Lc s + C m s

Vm

ω

1 J m s + Bm

Vm

reference input

amplifier

variable displacement mechanism

ω

variable displacement motor

controll law rotational speed sensor

average speed

Fig. 5 Block Diagram of Single Loop Motor Control System(1) TL order

controll law

D/A

PWM-ampli

variable mechanism

fier

Ps

1 J m s + Bm

ω

rotational speed sensor

Fig. 6 Block Diagram of Single Loop Motor Control System(2) shown in Fig. 3. Among of them, the V-axis steering is DESIGN OF STEERING SYSTEM shown in Fig. 7. When driver operates the car to steer, The steering system consists of 8 independent steering the button of steering station is first pressed, and then systems, each of them is all electrohydraulic position the operating wheel is to be rotated. servo system. It has 6 kinds of working station, and is sub-car

1 L1

Re1

Ri1

2

L0

b

C1

3

3

4

C4 C0

C2

C3

M

Fig. 7 Scheme of Steering System

Fig. 8 Diagram of Supporting Mode

c

Oc

R0

L1

O

DESIGN OF HORIZONTAL ADJUSTING SYSTEM The horizontal adjusting system uses three points support mode. It consists of liquid pendulum, amplifier and filter circuit, controller, electrohydraulic proportional direction and flow-rate valve, and cylinder. The supporting mode is shown in Fig. 8.

DESIGN OF CONTROL LAW When the truck is steered, the coordinated motion control to traveling system and steering system is necessary. In strictly speaking, this is an MIMO system. Here, for acquiring the simple controller construction and the fast processing time, the compound control law with order compensating and internal loop feedback is used.

CONCLUSIONS This study proposes a kind of the structure and realization method of the FCS for the truck based on CAN bus, and its design method of three sub-systems is discussed.

ACKNOWLEDGEMENT This project is supported by the foundation of Beijing Natural Science No. 3002008.

REFERENCES [1]P.J.Brucker,Scheduling Problems in Connection with Flexible Production Systems, Proceedings of the 1991 IEEE International Conference on Robotics and Automa-tion,Sacramento,California-April 1991 [2] G.Finke,J.Blazewicz,An Integrated System for Scheduling Machines and Vehicles in an FMS, Proceedings of the 1991 IEEE International Conference on Robotics and Automation, Sacramento, CaliforniaApril 1991 [3] Virginia Mary Lo, Heuristic Algorithms for Task Assignment in Distributed Systems, CH2021-4/84/0000/0030,1984,IEEE