CN202098458U - Electrically-controlled electric four-wheel steering system - Google Patents

Abstract

The utility model relates to an electronically controlled electric four-wheel steering system of a two-axle automobile. Including the front and rear wheel steering mechanism and angle sensor, stepping motor and its deceleration mechanism; the front wheel angle sensor is installed on the steering shaft of the steering wheel; the rear wheel angle sensor is installed on the output shaft of the motor deceleration mechanism-gear gearbox, The vehicle speed sensor is installed near the rotor of the speedometer, the yaw rate sensor is installed on the vehicle body at the center of mass of the vehicle, and the front and rear wheel steering mechanisms use rack and pinion steering mechanisms. When the vehicle is turning, each sensor transmits the sensing signal to the controller (ECU). After analysis and calculation, the (ECU) outputs a signal to the motor, and the motor determines the magnitude of the torque and the direction of rotation of the motor according to the signal from the (ECU). The rear wheels are driven to deflect at a certain angle through the rear wheel steering mechanism. The utility model has the advantages of few parts, light weight, compact design and good economy, and is not affected by the operating conditions of the engine during operation.

Description

Electronically controlled electric four-wheel steering system

technical field

The utility model belongs to the technical field of automobile parts manufacturing, in particular to an electronically controlled electronic four-wheel steering system of a two-axle automobile.

Background technique

Due to the slow response, inflexible steering, and poor directional stability at high speeds, the traditional single front axle steering system gradually fails to meet people's increasingly high requirements for active safety of vehicles. An efficient steering system is urgently needed to achieve good vehicle steering safety. In this situation, the four-wheel steering system came into being. The four-wheel steering (Four-Wheel Steering, 4WS for short) system means that during the steering process of the vehicle, the four wheels of the front and rear groups can play a steering role as required, so as to More effectively improve the maneuverability and handling stability of the vehicle. When turning at a low speed, the front and rear wheels of a 4WS vehicle steer in opposite phases, which can reduce the turning radius of the vehicle; when turning at a high speed, the front and rear wheels steer at the same phase, which can reduce the side slip angle of the vehicle's center of mass and reduce the steady-state overshoot of the yaw rate of the vehicle. amount, etc., can further improve the vehicle handling stability.

In the current 4WS system, except for the mechanical type, most of the hydraulic 4WS systems are used. This system has a large working pressure and stable and reliable work. However, due to the structure, system layout, sealing, energy consumption, and efficiency of the hydraulic system The existing shortcomings, as well as the response lag in the steering process, make it difficult for the hydraulic 4WS system to meet the requirements of modern four-wheel steering vehicles in terms of steering sensitivity and rapidity, which is not conducive to the stability of the car at high speed.

Utility model content

In order to overcome the shortcomings of the hydraulic four-wheel steering system in terms of structure, system layout, sealing, energy consumption, and efficiency, the utility model provides a hydraulic four-wheel steering system with few parts, light weight, compact design, small space occupation, and fuel economy. Good electronically controlled electric four-wheel steering system.

The technical solution to achieve the above object is as follows: electronically controlled electric four-wheel steering system, including front and rear wheel steering mechanisms, front and rear wheel angle sensors, vehicle speed sensors, yaw rate sensors and drive motor speed reduction mechanism, the drive motor The reduction mechanism adopts a speed change gearbox.

The front and rear wheel steering mechanisms are rack and pinion steering mechanisms.

The front wheel angle sensor is an inductive angular displacement sensor installed on the steering shaft of the steering wheel.

The rear wheel angle sensor also adopts an inductive angular displacement sensor, which is installed on the output shaft of the motor reduction mechanism-speed change gear box.

The vehicle speed sensor is installed near the rotor of the vehicle speed odometer, and adopts a photoelectric vehicle speed sensor.

The yaw rate sensor is installed on the vehicle body at the center of mass of the automobile, and adopts a piezoelectric jet rate sensor.

The sensing signals of the front wheel angle sensor, the rear wheel angle sensor, the vehicle speed sensor and the yaw rate sensor are all transmitted to the controller (ECU) through wires.

The CPU of described controller (ECU) is a 16 single-chip microcomputers with 256 bytes of RAM, adopts the 80C196KB single-chip microcomputer of Intel Corporation MCS-96 series, expands 27128EPROM program memory outside.

The motor reduction mechanism is connected with the stepping motor and the rear wheel steering mechanism.

The stepping motor receives the output signal of the controller (ECU) through the wire, and according to the instruction of the control signal, performs the rotation movement of the corresponding direction and angle, drives the movement of the rear wheel steering mechanism, and makes the rear wheel deflect to the left or right.

Compared with the traditional hydraulic four-wheel steering system, the beneficial technical effects of the utility model are reflected in the following aspects:

(1) Not affected by engine operating conditions. In the case of using 4WS, the steering system is not affected by the stop and turn of the engine, and the driver can obtain the maximum steering power even when the vehicle is stopped.

(2) It is beneficial to the overall layout design of the vehicle. Since the utility model uses more electrical equipment, a lot of mechanical connections are reduced, the parts are few, the weight is light, the design is compact, and the occupied space is relatively small, which can be more conducive to the general layout design of the whole vehicle.

(3) Good fuel economy. Because the power steering device of the utility model is not directly driven by the engine through the transmission system, the steering motor is only connected when the steering action occurs, so fuel can be saved. At the same time, because there is no loss of oil, the system works more reliably and runs faster.

Description of drawings

Fig. 1 is the overall layout of the utility model.

Fig. 2 is the schematic circuit diagram of the control system of the utility model.

The marks in the above figure are: 1, 3 front wheel 2 front wheel steering mechanism 4 front wheel angle sensor 5 steering wheel 6 vehicle speed sensor 7 controller (ECU) 8 yaw rate sensor 9 stepping motor 10 speed reduction mechanism 11, 13 Rear wheel 12 Rear wheel angle sensor 14 Rear wheel steering mechanism 15 Steering mode selection switch 16 External power supply 17 Steering mode indicator light 18 Fault display

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described further.

As shown in Figure 1, the electronically controlled electric four-wheel steering system includes a front wheel steering mechanism 2, a front wheel angle sensor 4, a rear wheel angle sensor 12, and a reduction mechanism 10; the front wheel steering mechanism 2 adopts a rack-and-pinion type Steering mechanism; the deceleration mechanism 10 is a gear box, and the front wheel angle sensor 4 is installed on the steering shaft of the steering wheel 5; the rear wheel angle sensor 12 is installed on the output shaft of the deceleration mechanism 10, and the vehicle speed sensor 6 is installed on the vehicle speed mileage Near the rotor of the watch, a photoelectric vehicle speed sensor is adopted, and the yaw rate sensor 8 is installed on the vehicle body at the center of mass of the automobile, and a piezoelectric jet sensor is used.

The perception signals of described front wheel angle sensor 4, rear wheel angle sensor 12, vehicle speed sensor 6 and yaw rate sensor 8 all pass to controller (ECU) 7, and described controller (ECU) 7 is a unit with 256 The 16-bit single-chip microcomputer of the byte RAM adopts the 80C196KB single-chip microcomputer of the MCS-96 series of Intel Corporation, and expands the 27128EPROM program memory externally.

The rear wheel steering mechanism (14) adopts a rack and pinion steering mechanism; the speed reduction mechanism 10 is connected with the stepper motor 9 and the rear wheel steering mechanism 14, and plays the role of speed reduction and torque increase.

The stepping motor 9 receives the output signal of the controller (ECU) 7, and performs rotational movement in the corresponding direction and angle according to the instruction of the control signal.

See shown in Figure 2, described controller (ECU) 7 is the core of whole system, by 80C196KB single-chip microcomputer 7-3, EPROM7-2, signal conditioning circuit 7-1, internal power supply circuit 7-4, motor drive circuit 7- 5. It is composed of display output circuit 7-6 and other parts. The controller (ECU) 7 has a built-in system fault self-diagnosis program, and the diagnosis result is notified to the driver through the fault display screen 18 . The system sets two steering modes, and sets the steering mode switch 15 and the steering mode switch indicator light 17. The driver can choose the traditional 2WS steering mode or the 4WS steering mode. The system can automatically select the steering mode switch according to the fault signal , that is, when the four-wheel steering system breaks down, the steering system is automatically converted from the 4WS mode to the 2WS mode, and the 4WS system failure indicator light 18 is lit at the same time.

When the vehicle is turning, the front wheel steering sensor 4 transmits the signal of the front wheel steering to (ECU) 7, and the vehicle speed sensor 6 transmits the speed signal of the vehicle to (ECU) 7. The output signal, the motor 9 determines the size of the torque and the direction of rotation of the motor according to the magnitude of the signal sent by the (ECU), and the rear wheel is driven by the rear wheel steering mechanism 14 to produce a certain angle of deflection. (ECU) also monitors the state of the vehicle in real time through the yaw rate sensor 8 and the rear wheel angle sensor 12, and feeds back the difference between the ideal value of the rear wheel angle and the actual angle to the stepping motor 9 to realize real-time Adjust the rear wheel angle to realize the four-wheel steering of the car. The whole system is powered by an external power supply 16, which is a vehicle battery.

Since the speed of the car changes rapidly when turning in actual driving (usually the turning is accompanied by a deceleration process), the control strategy adopted is: when the speed is lower than 40km/h, the front and rear wheels rotate in reverse, when the speed is 40km/h～60km/h The rear wheel steering mechanism hardly moves, and the front and rear wheels rotate in the same direction when the speed is higher than 60km/h. The size and direction of the movement are completely controlled by (ECU) 7 according to the set steering ideal value.

Claims (4)

1. electricity powered formula four-wheel steering system comprises foresteerage gear (2), front wheel angle sensor (4), trailing wheel rotary angle transmitter (12), speed reduction gearing (10); Said front wheel angle sensor (4) is installed on the steering shaft of steering handwheel (5); Said trailing wheel rotary angle transmitter (12) is installed on the output shaft of speed reduction gearing (10), and rotary angle transmitter (4) (12) adopts the inductance type angular-motion transducer; Said foresteerage gear (2) is a rack and pinion steering mechanism, it is characterized in that:

Also comprise car speed sensor (6) and yaw-rate sensor (8);

Said car speed sensor (6) is installed near the rotor of car speed mileage table, adopts the photo-electric car speed sensor; Said yaw-rate sensor (8) is installed on the vehicle body at automobile barycenter place, adopts piezoelectricity efflux angle speed sensor.

2. electricity powered formula four-wheel steering system according to claim 1; It is characterized in that: the perceptual signal of described front wheel angle sensor (4), trailing wheel rotary angle transmitter (12), car speed sensor (6) and yaw-rate sensor (8) is all passed to controller (ECU) (7); The CPU of described controller (ECU) (7) is 16 micro controller systems with 256 byte RAM; Adopt the 80C196KB micro controller system of the MCS-96 of Intel Company series, extend out the 27128EPROM program store.

3. electricity powered formula four-wheel steering system according to claim 1; It is characterized in that: said speed reduction gearing (10) is a speed-changing gear box; Said rear-axle steering mechanism (14) is a rack and pinion steering mechanism; Described speed reduction gearing (10) connects stepper motor (9) and rear-axle steering mechanism (14), plays reduction of speed and increases the square effect.

4. according to claim 1 or 3 described electricity powered formula four-wheel steering systems, it is characterized in that: said stepper motor (9) receives the output signal of controller (ECU) (7), and according to the indication of control signal, does rotatablely moving of respective direction and angle.

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