KR20020014309A - An automotive steering system having intelligent 4 wheels steering function - Google Patents

Abstract

PURPOSE: An intelligent four-wheel steering system of a vehicle is provided to improve stability by steering front and rear wheels of the vehicle individually with a motor without an additional hydraulic unit, and to prevent accidents by controlling with a microprocessor. CONSTITUTION: A steering system of a vehicle is composed of a signal input unit(10) measuring the steering angle of a steering wheel and vehicle speed; a main controller(20) processing the signal from the signal input unit according to logic and program, and outputting a control signal; and front and rear wheel driving units(30,40) controlled according to the control signal from the main controller. The front and rear wheel driving units consist of motion controllers(31,41), power amplifiers(32,42) amplifying signals from the motion controller, steering motors(33,43) operating according to the signal from the power amplifiers, and connecting units(35,45) operating steering racks(36,46) steering front wheels according to rotation of steering motors. Front and rear wheels are controlled with the electric motors individually. The vehicle is stabilized with steering rear wheels by reverse phase in changing the lane during traveling at high speed, and radius of rotation is reduced with steering rear wheels by same phase in parking or U-turn.

Description

An automotive steering system having intelligent 4 wheels steering function

The present invention relates to a steering apparatus of a vehicle having an intelligent four-wheel steering function, and more particularly, by steering a rear wheel together with a front wheel by a steering force generated independently of a vehicle engine, while maintaining a relatively short turning radius. The present invention relates to a vehicle steering apparatus having an intelligent four-wheel steering function.

In general, the steering system (steering system) of the vehicle is to control the attitude or direction of the vehicle desired by the driver, the hydraulic power to reduce the operating force on the steering wheel of the driver by obtaining hydraulic assistance by a pump connected to the crankshaft of the engine. Steering devices or vehicle speed-sensitive power steering devices that are suitable for driving by varying the hydraulic assistance power of the pump through the vehicle speed signal measured by measuring the vehicle speed are widely used.

However, such a hydraulic or vehicle speed-sensitive power steering device has a disadvantage of being dependent on the rotational speed of the engine because the hydraulic assist force is obtained by a pump connected to the crankshaft of the engine.

That is, although the vehicle load added to the tire of the vehicle is large at the time of stopping or at low speed of the vehicle, the hydraulic assistance force of the pump is low due to the low engine speed, while the vehicle load added to the tire of the vehicle at high speed of the vehicle. In spite of this relatively small rotation speed, the engine's high rotational speed increases the hydraulic assistance of the pump, which is the opposite of the state of the vehicle, that is, a large steering force is required at the time of stopping or at a low speed and a relatively small steering force is required at the high speed. Of course, there is a problem.

As a result, the driver generates the necessary assistance by using only a motor pump type or an electric motor that separates the pump that generates hydraulic auxiliary power from the engine, and not only performs the desired steering by the driver, but also consumes energy in accordance with the required state of the vehicle during steering. Also, the development of an effective steering system is urgently required.

Accordingly, the present invention has been made in view of the above, and has an object of controlling the front and rear wheels of the vehicle at the time of steering using an electric motor independent of the engine.

In addition, an object of the present invention is to stabilize the behavior of the vehicle by steering the rear wheel of the vehicle in reverse phase when changing the lane while driving the vehicle at high speed.

In addition, an object of the present invention is to relatively reduce the turning radius of the vehicle by steering the rear wheels in phase when the vehicle is parked or U-turn.

The present invention for achieving the above object, the signal input unit for detecting the steering angle and the vehicle speed of the steering wheel operated by the driver, and processing the signal according to the built-in logic (Logic) and program (Program) The main controller generates a control signal and the front and rear wheel drive devices controlled according to the control signal of the main controller, wherein the front and rear wheel drive devices controlled by the main controller are respectively a motion controller and the motion controller. A power amplifier for amplifying a signal, a steering motor operated at a predetermined rotation amount according to a signal transmitted through the power amplifier, and connecting means for manipulating a steering rack for steering a front wheel according to the rotational force of the steering motor do.

1 is a block diagram of a steering apparatus of a vehicle having an intelligent four-wheel steering according to the present invention;

2 is a block diagram of a front wheel steering system equipped with a steering device for a vehicle having an intelligent four-wheel steering function according to the present invention;

3 is a block diagram of a rear wheel steering system equipped with a steering device for a vehicle having an intelligent four-wheel steering function according to the present invention;

Figure 4 is a block diagram for the control of the steering device of the vehicle having an intelligent four-wheel steering function according to the present invention

5A and 5B are lane change state diagrams of a vehicle having an intelligent four-wheel steering function and a vehicle having a general steering function according to the present invention.

6 is a turning state diagram of a vehicle having an intelligent four-wheel steering function and a vehicle having a general steering function according to the present invention;

<Description of the symbols for the main parts of the drawings>

10: signal input unit 10a: steering angle signal unit

10b: vehicle speed signal unit 20: main controller

30: front wheel drive device 31,41: motion controller

32,42: power amplifier 33,43: steering motor

34,44: encoder 35,45: connection means

35a, 45a: Electronic clutch 35b, 45b: Connection plate

35c, 45c: Ball screw reader

36,46: Steering rack 36a, 46a: Ball screw

40: rear wheel drive device 47: preload means

47a: housing 47b: separator

47c: spring

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a steering apparatus of a vehicle having an intelligent four-wheel steering according to the present invention. The present invention detects a steering angle of a steering wheel operated by a driver and generates a steering angle signal unit. A signal input unit 10 comprising a vehicle speed signal unit 10b for generating a signal by measuring a vehicle speed and a vehicle speed, and processing the signal of the signal input unit 10 according to built-in logic and program. And a main controller 20 for generating a control signal and front and rear wheel drive devices 30 and 40 controlled according to the control signal of the main controller 20.

Here, the front wheel drive device 30 controlled by the main controller 20 is a motion controller 31 for outputting a control value of the control target according to the output signal of the main controller 20, and the motion controller 31 It consists of a power amplifier 32 for amplifying the signal and a steering motor 33 operated at a predetermined amount of rotation in accordance with the signal transmitted through the power amplifier 32.

In addition, the front wheel drive device 30 forms a main circuit 20 and a feedback circuit for stability of the control, that is, the main controller 20 detects the operating current of the steering motor 33. The motion is detected by a linear potentiometer for detecting the rotational degree of the encoder 34 and the steering motor 33 and a current sensor for detecting a power state supplied to the steering motor 33, respectively. A state of the controller 31 is also sensed to form a closed loop to optimally control the front wheel drive device 30.

Here, the motion controller 31 of the front wheel drive device 30 forms a closed loop to sense the operating current and the operating power of the steering motor 33 through the encoder 34 and the current sensor, respectively.

And, the steering motor 33 of the front wheel drive device 30 is provided with a connecting means 35 for operating a steering rack 36 for steering the front wheels in accordance with the rotational force of the steering motor 33, the connection means ( As shown in FIG. 2, an electromagnetic clutch 35a connected with the operation of the steering motor 33, a connection plate 35b operated by the electromagnetic clutch 35a, and the connection plate 35b are provided. It is provided in the ball screw (36a) section of the steering rack 36 is composed of a ball screw reader (35c) for moving the steering rack 36 as it moves left and right.

Meanwhile, the rear wheel drive device 40 includes a motion controller 41, a power amplifier 42, and a steering motor 43 controlled by the main controller 20 in the same way as the front wheel drive device 30 described above. In addition, the connecting means 45 for manipulating the steering rack 46 for steering the rear wheels in accordance with the rotational force of the steering motor 43 is also a ball screw of the steering rack 46 via the electromagnetic clutch 45a and the connecting plate 45b. It consists of a ball screw reader 45c which moves the steering rack 46 as it engages in the section (46a) and moves left and right.

In addition, the rear wheel drive device 40 also forms a feedback circuit with the main controller 20 in the same manner as the front wheel drive device 30 described above for the stability of the control.

However, the rear wheel drive device 40, unlike the front wheel drive device 30, is provided with a preload means 47 on one side of the steering rack 46 at intervals from the connecting means 45, this preload means 47 As shown in FIG. 3, the housing 47a forms an empty space so as to surround the separating plate 47b integrally formed in the steering rack 46, and the separation plate 47b in the housing 47a is centered. It consists of the spring 47c provided in both sides.

On the other hand, the main controller 20 for controlling the front and rear wheel drive device (30, 40) is largely composed of a main program, a control program and a communication program for the control, the main program is required to control the system variables and other Since the memory variable is initialized and the offset value (Off-Set Value) of each sensor signal is determined, as shown in FIG. 4, a car speed interrupt routine and a watch dog timer interrupt routine are shown. Signal is inputted.

In addition, the control program operated by the main program is a motion controller 31 via a software time interrupt interrupted by a current state detection signal among feedback signals of the front and rear wheel drive devices 30 and 40. And a control algorithm for generating a control command of (41).

In addition, a communication program for communication between the main program and the motion controllers 31 and 41 of the front and rear wheel drive devices 30 and 40 or other external devices is provided with an interface (for example, the motion controllers 31 and 41). Interface) and communication protocol (Communication Protocol) of course mutual communication is made.

Hereinafter, the operation of the present invention will be described in detail.

When the steering angle signal unit 10a and the vehicle speed signal unit 10b are changed to the signal input unit 10 as the vehicle runs, the main program of the main controller 20 connected to the signal input unit 10 is input. The control value is generated by initializing the vehicle speed signal and the watchdog timer.

Subsequently, a control signal of the main program generates a control command through a control algorithm to manipulate the motion controllers 31 and 41, wherein the control algorithm controls the current state of the steering motors 33 and 43 to the encoders 34 and 44. In addition, the control algorithm is interrupted according to the signal detected through) and re-executed under the set condition.

At this time, the control algorithm for controlling the motion controllers 31 and 41 is performed through a communication program having a communication protocol for communicating with the main program through the interface of the motion controllers 31 and 41.

Referring to the operation of the front wheel drive device 30 that is steered in accordance with the control process of the main controller 20 in more detail, the steering wheel is used to change the position of the driving vehicle (when changing lanes or turning). When operated, the steering angle of the steering wheel is input to the main controller 20 together with the vehicle speed signal via the steering angle signal unit 10a via the signal input unit 10.

Subsequently, the main controller 20 transmits a control signal corresponding to the steering angle and the vehicle speed detected by the motion controller 31, and the signal of the motion controller 31 is controlled by the power amplifier 32. 33), the steering motor 33 is rotated clockwise or counterclockwise.

At this time, since the electronic clutch 35a of the connecting means 35 is operated together with the operation of the steering motor 33 to connect the connecting plate 35b and the steering motor 33, the ball of the connecting plate 35b. The steering rack 36 which forms the section of the ball screw 36a engaged with the screw reader 35c is moved in one of the left and right directions according to the rotation direction of the steering motor 33 to steer the front wheels. .

On the other hand, the main controller 20 detects the rotation amount and the current state of the steering motor 33 is operated through the linear potentiometer and the encoder 34, as well as the power state supplied to the steering motor 33, At the same time, by detecting the electrical signal for the state of the motion controller 31, the power of the power supplied to the steering motor 33 and the signal of the current state is fed back to continuously generate an electrical signal value corresponding to the desired steering angle Of course, the steering motor 33 is controlled via the H-bridge circuit of the power amplifier 32 while controlling the controller 31.

In addition, the operation of the rear wheel drive device 40 according to the present invention is the same as the front wheel drive device 30 described above, the signal of the steering angle signal part 10a and the vehicle speed signal part 10b is input through the signal input part 10. The controller 20 is input to the steering motor 43 through the motion controller 41 and the power amplifier 42, and rotates the steering motor 43 in a clockwise or counterclockwise direction so that the electronics of the connecting means 45 are rotated. A steering rack 46 having a ball screw 46a section engaged with the ball screw reader 45c of the coupling plate 45b via the clutch 45a is left and right according to the rotational direction of the steering motor 43. It is moved in one of the right directions to steer the rear wheels.

Here, the preloading means 47 provided on one side of the steering rack 46 allows the return operation to be quickly performed after the steering rack 46 is moved, that is, when the steering rack 46 is moved to the left side of FIG. 3. The spring 47c positioned on the left side of the means 47 is compressed, and when the spring 47c is restored after the return, the compressed spring 47c is restored, thereby pushing the separating plate 47b of the steering rack 46. Of course, the return of the rack 46 is returned quickly and with relatively little force.

On the other hand, the main controller 20 detects the rotation amount and the current state of the steering motor 43, which is operated in the same manner as the front wheel drive device 30, through the linear potentiometer and the encoder 44, as well as the steering motor ( 43) together with the power supply to the steering motor 43, and at the same time the electrical signal for the state of the motion controller 41 is fed back to the power supply and the current signal supplied to the steering motor 43 to the desired steering angle Of course, the steering motor 43 is controlled through the H-bridge circuit of the power amplifier 42 while controlling the motion controller 41 by continuously generating corresponding electric signal values.

As such, the front and rear wheel drive devices 30 and 40 steered by the motors 33 and 43 operated through the main controller 20 generating control signals according to the steering angle and the vehicle speed according to the present invention are generally two. The wheel steering vehicle has various advantages, and in particular, when the dashed line changes or turns, the movement width thereof is relatively short or narrow.

That is, FIGS. 5A and 5B show a lane change during high-speed driving of a four-wheel steering and a general two-wheel steering vehicle according to the present invention. FIG. When changing from Va) to the final position Vd, the front and rear wheels of the vehicle are steered in the same inclination angle (a, b) among the first and second moving positions Vb and Vc located in the movement width L. While the direction of the vehicle body is always constant, Fig. 5 (B) showing two-wheel steering shows the first and second moving positions located within the moving width L 'when changing from the initial position Va to the final position Vd of the vehicle. Among the Vb and Vc, the front wheel and the rear wheel of the vehicle are steered at different inclination angles a 'and b' to change toward the lane where the direction of the vehicle body is changed, causing an instant instability.

In addition, Figure 6 shows the low-speed turning of the four-wheel steering and the general two-wheel steering vehicle of the present invention when the present invention moves from the initial position (V1) of the vehicle to the final position (V3) inside the vehicle of the moving position (V2) While the inclination angles (c, d) of the wheels positioned outwardly and the outwardly located wheels are all the same, and their rotation radius also has different radiuses (R, R) through the same gap (G, G '), When the two-wheel steering vehicle moves from the initial position (V1) to the final position (V3), the inclination angles (c ', d') of the wheels located inside the vehicle at the moving position (V2) and the wheels located outward are different. The radius of rotation (R ', R') is different in size but located on the same center line, the radius of rotation becomes relatively large.

As described above, according to the present invention, since both the front and rear wheels of the vehicle are equipped with independent steering control functions by the motor and are controlled by the microprocessor as well as the steering stability, the reliability deterioration according to the driver's instability in the event of a sudden accident occurs. It is effective to prevent.

In addition, the present invention is to stabilize the behavior of the vehicle by steering the rear wheel of the vehicle in reverse phase when changing the lane while driving the vehicle at high speed while steering the rear wheel in the same phase when the vehicle parking or U-Turn The turning radius of the vehicle is relatively reduced compared to the two-wheel steering vehicle.

In addition, the present invention can be manufactured in a small size as well as steering the vehicle by the electric motor without a separate hydraulic device has a large expandability effect.

Claims (7)

Front and rear wheel drive controlled according to the generated signal of the main controller 20 to process the signal of the signal input unit 10 for detecting the steering angle of the steering wheel operated by the driver according to the built-in logic and program to generate a control signal Device 30, 40, the main controller 20 is the front and rear wheel drive to continuously detect the feedback of the operation results of the front and rear wheel drive device (30, 40) operated by the output control value Steering device of a vehicle with intelligent four-wheel steering to form a closed loop independent of (30, 40), respectively. The front and rear wheel drive apparatuses 30 and 40 further include motion controllers 31 and 41 for outputting control values to be controlled according to output signals from the main controller 20, and the motion controllers 31 and 41. Power amplifiers 32 and 42 for amplifying the signals of the signal 41 and the steering motors 33 and 43 operated at a predetermined rotational amount according to the signals transmitted through the power amplifiers 32 and 42, and the steering motors 33 and 33; , 43) a steering device of a vehicle having an intelligent four-wheel steering function, characterized in that it is composed of connecting means (35, 45) for moving the steering rack (36, 46) left and right. The steering motor (33, 43) of the front and rear wheel drive device (30, 40) is connected to the main controller 20, the operating current through the encoder (34, 44), linear potentiometer and current sensor And the rotation amount and the supplied power state, respectively, and the intelligent four-wheel steering, characterized in that the state of the motion controllers 31 and 41 is detected by the main controller 20 through an interface for receiving a control signal. Steering device of a vehicle having a function. The method of claim 3, wherein the motion controller (31,41) is to form a closed loop to sense the operating current and the operating power of the steering motor (33, 43) through the encoder (34, 44) and the current sensor, respectively A vehicle steering apparatus having an intelligent four-wheel steering function. 3. The electronic clutch (35a, 45a) of claim 2, wherein the connecting means (35, 45) of the front and rear wheel drive (30, 40) are connected together with the operation of the steering motor (33, 43). The coupling plates 35b and 45b operated by the clutches 35a and 45a and the connecting plates 35b and 45b are engaged with the ball screws 36a and 46a of the steering racks 36 and 46 to be left and Steering device of a vehicle having an intelligent four-wheel steering function, characterized in that consisting of a ball screw reader (35c, 45c) for moving the steering rack (36,46) as it is moved right. 6. The rear wheel drive device (40) according to claim 5, wherein the rear wheel drive device (40) is provided with a preloading means (47) for generating a repulsive force to one side of the steering rack (46) so that a return operation can be performed quickly when the steering rack (46) returns. Steering device of a vehicle having an intelligent four-wheel steering function, characterized in that. 7. The preloading means (47) according to claim 6, wherein the preloading means (47) includes a housing (47a) which forms an empty space to surround the separating plate (47b) integrally formed in the steering rack (46), and the separating plate (in the housing 47a). 47b) Steering device of a vehicle having an intelligent four-wheel steering function, characterized in that consisting of a spring (47c) provided on both sides.