JPH09169281A - Electronically-controlled steering system of car and controlmethod thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stable steering feeling of a steering handle based on the high, middle, slow speed of a vehicle and to insure the steering stability. SOLUTION: An electronic controlled steering system and a control method thereof, may be applied to an electronic steering controller to determine the compensated inclination of current to the vehicle speed during running, based on the speed signal from a speed sensor 22, to determine the compensated inclination of current to the steering absolute angle along with the change in steering angle from the steering angle sensor 23, to calculate steering angular velocity by measuring pulse timing of the steering angle signal from the steering angle sensor 23, to determine the compensated inclination of current associated with the steering angular velocity based on the speed. By summing these compensated currents, and PID computing together with the external throttle voltage and the feedback current from an electronic steering control valve, a compensated current to supply to the electronic steering control valve is determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle electronically controlled steering system and a control method thereof for adjusting a flow rate pressure of a steering wheel based on a traveling speed of a vehicle.

[0002]

2. Description of the Related Art In general, when driving a vehicle, if the frictional force between the wheels of the vehicle and the ground is large, the operating force of the steering handle becomes large and it becomes impossible to steer quickly. In order to solve this, the vehicle is required to have a light and steerable steering device. To solve this,
An electronically controlled steering machine was developed. Therefore, the electronically controlled steering machine reduces the operating force of the steering wheel to freely select the steering gear to prevent kickback (kick back) of the steering wheel due to an impact from the road surface. It reduces the shimymotion of the spinning wheels.

That is, an electronically controlled steering machine of a vehicle receives hydraulic oil supplied from a pump, and a steering control valve selectively supplies the hydraulic oil to both sides of a power cylinder according to the steering of a driver to operate a steering wheel. Is to do.

When the vehicle travels at a low speed, the steering force (catch-up) is lightened so that the steering can be performed with a small force. By increasing the weight, the steering feeling of the driver who operates the steering wheel is increased. The steering force of the vehicle is actively adjusted according to the traveling speed to improve steering stability (on-cen
ter feel).

In such an electronically controlled steering machine, as shown in FIG. 11, the hydraulic oil supplied from the pump P is distributed to two pipelines, and one pipeline follows rotation of the steering handle. , Power cylinder 2 through steering control valve 1
Is selectively supplied to both sides of. From the other line, it is supplied to the reaction force control device 6 via the pressure control valve 5. At this time, the electronic control unit 4 controls the pressure control valve 5 to control the reaction force chamber pressure of the reaction force control device 6 in accordance with the traveling speed of the vehicle detected by the vehicle speed detection unit 3 to increase the steering force of the vehicle. It is actively controlled according to the traveling speed of the vehicle.

Further, as shown in FIG. 12, a steering control valve 1 in which a linear reaction force appears according to the control pressure of the flow rate.
The pinion 11 is fixed to the inside thereof, and the reaction force piston 12 that slides in the radial direction is assembled to the shaft S. Therefore, the piston installed on the rear surface of the pinion covers and tightens the outer peripheral surface of the shaft S so as to firmly grasp the outer peripheral surface of the shaft S according to the pressure control amount. The torsion bar 14 and the shaft S are fixed by the center pin 15,
The body valve 16 and the binion 11 are connected to the stopper pin 18
The driver operates the steering handle so that the driver can feel the steering feeling.

As described above, in the electronically controlled steering machine, when the driver rotates the steering wheel, the torsion bar 14 causes angular displacement, and the shaft area has an orifice area corresponding to the angular displacement. Formed by the edge, a pressure corresponding to the orifice area is generated and supplied to the left and right cylinders of the steering control valve 1.

The conventional electronically controlled steering machine having such a structure has an inherent current compensation slope showing the control current characteristic of the steering valve in order to compensate the flow rate according to the steering angular velocity related to the vehicle speed. doing. Therefore, the bypass pressure is increased according to the traveling speed of the vehicle, and the bypass pressure is instantaneously decreased when the steering angular velocity is generated.

Nevertheless, since the technique does not consider the influence of the steering angular velocity with the traveling speed of the vehicle,
When the steering angular velocity was generated irrespective of the traveling speed of the vehicle, the gradients of the bypass pressure compensation amounts were all the same. Therefore, if the compensation inclination is adjusted based on the intermediate speed of the vehicle, the amount of compensation at the time of high-speed driving of the vehicle becomes excessive and the steering feeling of the steering wheel becomes momentarily lighter. When the compensation inclination is adjusted, the amount of compensation during low-speed traveling is small, so there is a problem that the feeling of steering becomes heavy.

Moreover, since the area where the steering angular velocity is generated varies depending on the traveling speed of the vehicle, as described above, when the inclinations of the bypass pressure compensation amounts are all set to be the same, the driver of the vehicle feels uncomfortable. There was a problem.

Further, as a typical conventional technique,
A steering force control device for a power steering device is disclosed in Japanese Patent Laid-Open No. 63-2427.
No. 74 (1988.10).
The steering force control device is a flow rate control system in which a solenoid valve adjusts the supply flow rate, and is a device for controlling the steering force only based on information from a vehicle speed sensor and a steering angle sensor. Direction angle θ is the vehicle speed sensor 40
And a steering wheel torque TMa corresponding to the steering angle sensor 45 and steering output torque TSa calculated in the characteristic map, and control corresponding to the calculated steering wheel torque TMa and steering output torque TSa. The current value is calculated from the characteristic map to control the solenoid valve. As a result, the steering feeling of the steering wheel is improved.

However, since the technique does not consider the influence of the steering angular velocity, when the steering angular velocity is generated, the bypass input is instantaneously reduced to reduce the flow rate regardless of the traveling speed of the vehicle. This means that it has the same drawbacks as the above technology.

After all, when the steering angle is changed while the vehicle is traveling, it can be known that the insufficient flow rate must be quickly compensated.

[0014]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an electronically controlled steering system provided with an electronically controlled steering device for adjusting the flow rate pressure of a steering handle according to the traveling speed of a vehicle, and a control method thereof. The main purpose is.

Another object of the present invention is to provide an electronically controlled steering system for calculating a compensating current based on a vehicle speed, a steering angle and a steering angular velocity of a vehicle and controlling a hydraulic pressure of an electronically controlled steering machine. It is to provide the control method.

Another object of the present invention is to provide an electronically controlled steering system and a control method therefor having a current compensation slope for adjusting a flow rate of a steering angular velocity corresponding to a vehicle speed while the vehicle is traveling. To do.

[0017]

SUMMARY OF THE INVENTION Therefore, according to the present invention, there is provided electronically controlled steering means for adjusting the left and right chamber flow rates of a power cylinder for applying steering force to a steering wheel, and a vehicle speed sensor for detecting the speed of a vehicle. A steering angle sensor that detects a steering angular velocity while the vehicle is traveling, a throttle sensor that detects an applied current based on an opening / closing angle of a throttle valve, and an interface unit that converts a current signal of the sensor or the like into a voltage and outputs the voltage. A control unit that receives an input signal from the interface unit, processes the received signal based on a system program and adjusts the flow rate of the left and right chambers of the power cylinder, and the electronic control steering unit based on the control of the control unit. A drive unit for applying a drive voltage to the means, and a current track for inputting to the control unit by detecting a drive current flowing in the electronically controlled steering means. Parts and constituted by an electronic control steering system and a display driving unit that apply voltage to the photodiode LED under the control of the control unit.

Further, the method of controlling the electronically controlled steering machine according to the present invention corresponds to the step of receiving the input of the vehicle speed, the steering speed, and the steering angular velocity from the vehicle speed sensor and the steering angle sensor, and the input data. It comprises a step of calculating a current value, a step of detecting the throttle valve voltage and a current of the electronically controlled steering means, a step of driving the electronically controlled steering valve by the drive current determined in the above step, and the like.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic block diagram of an electronically controlled steering machine and its control section in an electronically controlled steering system applied to the present invention. The electronically controlled steering machine 100 includes a steering control valve 1 and a flow rate control valve 20. Here, since the steering control valve 1 has been described with reference to FIG. 12, detailed description thereof will be omitted. Flow control valve 20
Is composed of a housing 17 of the steering control valve 1 and a housing 2 integrally connected. Inside the housing 2, a spool 3 is elastically supported at one end by a spring 4, and the other end is connected to a solenoid 7 so as to move up and down. Inside the housing 2, a first group 8 and a second group 9 are formed above and below the spool 3. The first channel 12 is provided in the first group 8.
Is formed and communicates with the right hydraulic passage 31 of the steering control valve 1. A second flow passage 13 is formed in the second group 9 and communicates with the left hydraulic passage 32. A bidirectional orifice 35 is formed in the center of the spool 3, which allows the first group 8 and the second group 9 to communicate with each other, so that the flow rate can be freely moved.

The steering control valve 1, the flow rate control valve 20 and the like as described above are disclosed in Japanese Patent Application No. 8-169 filed before the present application.
No. 043 [US Pat. No. 08 / 670,129 or German Patent No. 1962606.4]
In detail.

Therefore, in the electronically controlled steering machine 100, when the steering handle is turned to the right, the pressure in the right chamber 33 rises, the spring 4 side becomes high pressure in the flow control valve 20, and the left chamber becomes the tank 40. And the solenoid 7 side is brought to the atmospheric pressure state. On the contrary, when the steering handle is turned to the left, the pressure in the left chamber 34 rises, and the solenoid 7 side becomes high pressure. At this time, right chamber 3
3 is connected to the tank 40 to bring the spring 4 side into the atmospheric pressure state. As described above, in the electronically controlled steering machine 100, the high pressure end and the low pressure end are formed in both directions according to the left-right movement of the steering handle, so that the pressure formed via the orifice 35 has the same characteristics in both directions. Is configured.

The electronically controlled steering machine 100 communicates with the fluid discharge lines L and R of the power cylinder 30 composed of the left and right chambers 34 and 33. The fluid line I connects the pump P to the fluid return line. The tank 40 is connected by T. The tank 40 is connected to the fluid supply pump.

The electronic steering control unit 50 is connected to the vehicle speed sensor 22 and the steering angle sensor 23, receives the vehicle speed signal and the steering angle signal, and controls the operation of the renoid 7 based on the result.

As shown in the block diagram of FIG. 2, the electronic steering control unit 50 is a control unit 2 including a microprocessor.
1 is included. The control unit 21 is connected to a vehicle speed sensor 22 that detects a vehicle speed by an interface unit 25, a steering angle sensor 23 that detects a steering angle of a steering wheel, and a throttle sensor 24 that detects an opening angle of a throttle valve. . The interface unit 25 shapes these input currents into predetermined rectangular waves and converts them into voltage values. The control unit 21 supplies a control signal to the solenoid drive unit 27 according to a predetermined system program based on the input from each sensor in order to control the operation of the solenoid 7 of the electronically controlled steering machine 100. The solenoid drive unit 27 causes a predetermined current to flow to the solenoid coil 26 based on the control signal of the control unit 21 so that the solenoid 7 moves the spool 3 to bypass the fluid. Therefore, as will be described later, the left and right chambers 3 of the power cylinder 30.
Adjust the hydraulic pressure for 4, 33.

The current tracking section 28 detects the current flowing through the solenoid coil 26 and inputs it to the control section 21. The display drive unit 29 is provided with a display light emitting diode LED, and is turned on and off based on a signal from the control unit 21.

On the other hand, the electronic steering control section 50 controls the electronically controlled steering machine 100 based on the principle of the present invention, and its operation flowchart is shown in FIGS. The electronic steering control unit 50, when the vehicle start key is pressed,
First, the system is initialized at step 200. In post-initialization step 210, the vehicle speed is calculated. As shown in FIG. 4, the vehicle speed calculation is based on the principle of the present invention. In order to ensure accuracy, the control unit 21 is provided with a large number of RAMs and is connected to an internal timer for 1.42 seconds. The vehicle speed is detected sequentially for each. That is, in step 411, 7
It detects whether 2 milliseconds (msec) has elapsed, and calculates the vehicle speed only when it has elapsed.
In step 2, every 1.42 seconds, the vehicle speed in one of the RAMs is calculated from the vehicle speed signal frequency × 1.42 seconds. In the next step 413, the current speed is detected, but the speed is determined from the speed plus the vehicle speed stored in all RAM.

The vehicle speed thus determined determines the compensation current value stored in the look-up table that is passed through the solenoid 7 of the flow control valve 20 according to the vehicle speed as shown in FIG. That is, 1 A at a vehicle speed of 0 to 60 km / h, 0.4 A at a vehicle speed of 60 to 80 km / h, 8
It is 0.4 to 0.1 A at 0 to 60 km / h, 16
At 0 km / h and above, 0.1 A flows. At this time, the compensation current value for the vehicle speed is determined.
If the current value associated with the vehicle speed is determined in this way, step 22
At 0, the steering absolute angle is calculated. As shown in FIG. 5, the steering absolute angle is detected when the vehicle speed is 40 km / h or more. According to the input from the steering angle sensor according to the vehicle speed, the current compensation inclination with respect to the electronically controlled steering device is obtained. Is determined.

That is, in step 421, the vehicle speed is 40
If it is 40 km / h or less, the process proceeds to step 422, the compensation current value associated with the steering angular velocity is set to zero, and the process is returned. If the vehicle speed is 40km / h
If the above is the case, in step 423 it is detected whether the steering wheel is in neutral. If it is not in neutral, the process proceeds to step 422, and the compensation current value associated with the steering angle is zero. To judge. If the steering wheel is in the neutral position, it is determined in step 424 whether there is an alternate signal between the on-center (ON-CENTER) A phase and the off-center (OFF-CENTER) B phase.

If there is a signal alternating from the A phase to the B phase or from the B phase to the A phase by about ± 10 °, the current compensation slope as shown in FIG. 8 is provided in steps 425 and 426. That is, when the vehicle speed is 80 km / h or less, the maximum steering absolute angle is 20 °, and when it is 80 km / h or more, the maximum steering absolute angle is 60 °. At this time, the vehicle speed is 7
From 0 km / h to 80 km / h, it has a compensation slope of 0.01 A to 0.04 A, and 80 km / h to 160 km /
Up to h, it has a compensation slope from 0.04A to 0.172A. At this time, the period in which the compensation current from the A phase to the B phase reaches 0.1 A is within 1 second, and the compensation current decrease time from the B phase to the A phase is within 0.5 ms. Furthermore, the vehicle speed is 160k
When the steering absolute value is 60 ° or more at m / h or more, the compensation current value is 0.172 A, which is almost unchanged.

As described above, in steps 425 and 426, etc., since the steering angle is detected by ± 10 °, the current compensation slope can be obtained. In the next step 230, the current compensation slope with steering angular velocity is determined.

As shown in FIG. 6, the steering angular velocity is generated by the operation of the steering handle while the vehicle is traveling. To detect such steering angular velocity, a pulse signal is output from the steering angle sensor. , Calculate the acceleration based on the cycle. Therefore, in step 431, it is determined whether the steering angle is valid. That is, it is determined whether the steering angle is maintained at the on-center. If not valid, step 43
At 2, the steering angle compensation current is set to zero. If the steering angle is valid, it is determined whether or not the steering angle is changed to ± 20 ° or more in the current steering angle and there is a lane change intention.

If there is no intention to change lanes, step 4
At 33, the current steering angle is compared with the previous steering angle. At this time, if the steering angle is moved within ± 20 °, it is determined whether the steering wheel is being restored. That is, if the previous steering angle is 30 ° and the current steering angle is 20 °, it is determined that the steering handle is being restored.

If the steering handle is being restored, step 4
At 34, the steering wheel may be restored and pass through the neutral position, so that the compensating current is suddenly reduced to the neutral position.

On the other hand, if there is an intention to change the lane in step 433, the compensating current to the steering angular velocity with the vehicle speed is calculated. This is the vehicle speed +
It has steering angular velocity compensation current characteristics.

Taking the lookup table of FIG. 10 as an example, when the vehicle speed is 120 km / h and the steering angular velocity is 800 °, the compensation current is determined to be 505 mA.

Thereafter, in step 437, it is determined whether the steering angle is ± 20 ° or more and is maintained for 10 seconds or more while the vehicle is traveling. This is the case when the vehicle remains on a slow curve for a long time.

If not, the steering handle is returned to the neutral position, and the current compensation associated with the steering angular velocity is completed. On the contrary, when the steering angular velocity is ± 20 ° or more and is continued for 10 seconds or more, the process proceeds to step 438, and the current is increased with a constant ratio of 10 seconds, and the steering feeling of the steering wheel is improved. It can relieve the person's fatigue.

In this way, the compensation current values for the vehicle speed, the steering absolute angle and the steering angular velocity are determined, and in step 240, the corresponding current value based on the angular compensation inclination is read from the look-up table. The current value thus read out is used to calculate the total current value in step 241. The total current value I is I _U + I _W + I _P.

When the total current value I is calculated in this manner, the control unit (210 is a PAM (Pulse Width Modulatio)
n) A predetermined current value I is supplied to the solenoid 7 by supplying a duty sigunal to the drive controller.

In the next step 243, the control unit 21
Is the throttle valve voltage and the current transition detected by the current transition unit 28 in the solenoid coil 26 is input. In this way, the control unit 21 uses the input median constants and the like as PIs.
D calculation is performed, and when drawing or adding a current associated with a change in the steering angular velocity, the reversal gain, that is, the PID gain is minimized to calculate the PWM (Pulse Width Modulation) duty, and based on this calculation , Determines the compensation current supplied to the solenoid. The control unit 21 drives the flow rate control valve 20 by generating a PWM duty signal for the compensation current thus determined and controlling the drive control unit.

[0041]

As described above, the present invention adjusts the bypass flow rate of the electronically controlled steering device by calculating the compensating slope corresponding to the vehicle speed, the steering absolute angle and the steering angular velocity while the vehicle is traveling. The stable steering feeling of the steering wheel can be obtained based on the high speed, medium speed, and low speed of the vehicle, and the steering stability is ensured.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an electronic steering control system provided with an electronic control steering machine according to the present invention.

FIG. 2 is a block diagram of an electronically controlled steering system according to the present invention.

FIG. 3 is a main flowchart for controlling an electronically controlled steering machine according to the present invention.

FIG. 4 is a flowchart for calculating a vehicle speed according to the present invention.

FIG. 5 is a flowchart showing an operation of calculating a compensation current according to a steering absolute angle according to the present invention.

FIG. 6 is a flowchart for calculating a current value with respect to a steering angular velocity according to the present invention.

FIG. 7 is a graph of compensation current based on vehicle speed.

FIG. 8 is a graph of compensation current based on steering absolute angle.

FIG. 9 is a graph of a compensation current corresponding to a steering angular velocity based on a vehicle speed.

FIG. 10 shows a lookup table.

FIG. 11 is a block diagram schematically showing a configuration of a conventional electronic steering control system.

FIG. 12 is a sectional view showing a flow control valve applied to a conventional electronic steering control system.

[Explanation of symbols]

 1: Steering control valve 20: Flow control valve 21: Control part 22: Vehicle speed sensor 23: Steering angle sensor 24: Throttle sensor 25: Interface part 26: Solenoid coil 27: Solenoid drive part 28: Current redirection part 29: Display drive

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jaea Duk, Kim South Korea, Kwangwon-do, Wonju City, Won-dong, Hanju APT. 102-1401

Claims (7)

[Claims] 1. An electronically controlled steering system for a vehicle, comprising: a vehicle speed sensor for detecting a speed while the vehicle is traveling; a steering angle sensor for detecting a steering angle associated with the operation of a steering handle of the vehicle; A throttle sensor that detects the opening angle of the throttle valve, an interface unit that receives signals from all the sensors and the like to convert current into a voltage value, and an input signal that is received from the interface unit. Based on the steering angle with respect to the vehicle speed while the vehicle is traveling, and a control unit that determines a current compensation inclination such as steering angular velocity, an electronically controlled steering device bypasses the flow rate in both directions based on a control signal from the control unit. So that the voltage of the throttle valve and the current detected from the electronically controlled steering device are supplied to the control unit by a current tracking unit, and from the control unit Vehicle electronic control steering systems, characterized by being configured from a light emitting diode driving unit such as to induce driving of the light emitting diode for displaying the operation of the electronic control steering motor based on the control signal. 2. The vehicle according to claim 1, wherein the control unit is provided with a large number of RAMs cooperating with a counter so that the vehicle speed is individually input at an interval of 1.42 seconds according to the vehicle speed signal. Electronically controlled steering system. 3. The electronically controlled steering system for a vehicle according to claim 1, wherein the control unit calculates the steering angular velocity so that the steering angle signal is calculated by an internal timer. 4. A method for controlling an electronically controlled steering machine, the step of calculating a vehicle speed according to a vehicle speed signal, and the absolute steering angle is continuously determined at intervals of ± 10 °, and the current associated with the absolute steering angle is determined. Calculating a compensation slope value, measuring a pulse time of a signal input from a steering angle sensor to determine a steering angular velocity, calculating a compensation current for the steering angular velocity, and steering with the vehicle speed. From the step of calculating the compensation current of the angle and the steering angular velocity, and the step of detecting the throttle valve voltage and the reversal current from the control valve, calculating the PID for the compensation current, and determining the compensation current. A control method characterized by being configured. 5. The vehicle speed detecting step comprises a step of judging whether or not milliseconds have elapsed after the vehicle is started, and a RA having a large number of counters.
5. The control method according to claim 4, further comprising the step of sequentially inputting a vehicle speed to M at 1.42 second intervals and adding the vehicle speeds of these RAMs to calculate the vehicle speed. . 6. The step of calculating the steering absolute angle is such that the vehicle speed is 4
If the steering wheel is neutral, the steering angle is ± 10 ° each from on-center to off-center, or from off-center to on-center. 5. The control method according to claim 4, further comprising: a step of detecting whether the steering angle has been changed to, and a step of determining a compensation current according to the detected steering angle. 7. The steering angle velocity is detected when the steering angle is determined to be valid in the steering angle calculation step and when the steering angle is changed by ± 20 ° or more, The control method according to claim 4, further comprising a step of calculating a compensation current based on the current compensation slope.