KR930000647B1 - Steering angle middle point detecting apparatus - Google Patents

Abstract

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Description

Steering Angle Key Point Detection Device

1 is a partially broken front view showing an embodiment of a power steering apparatus according to the present invention.

2 is an enlarged cross-sectional view taken along the line II-II of FIG.

3 is an enlarged cross-sectional view taken along line III-III of FIG. 1 showing the structure of the rotation detector.

4 is a waveform diagram showing an output waveform of a rotation detector.

5 is a block diagram showing the configuration and operation of the controller.

6 to 10 are flowcharts for explaining respective control operations.

11 is a graph showing the characteristics of the relationship between the motor current and torque in the indicating current function.

12 is a flowchart of angular velocity control.

* Explanation of symbols for main parts of the drawings

6: torque sensor 8: motor

17: rotation detector 18: vehicle speed detector

71c: Midpoint detection section 71d: Steering angle determiner

71g: Angular velocity detector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering angle midpoint detection device for detecting a midpoint of a steering angle of a steering mechanism, and more particularly to an improvement for the purpose of improving the midpoint detection accuracy.

In the power steering apparatus which assists the steering force based on the detection and the result of the steering torque applied to the handle, the steering angle is usually used as one of the steering conditions.

As a means for detecting a steering angle conventionally, it is known to use a sensor such as a potentiometer for detecting its movement on the handle shaft or the rack shaft.

In such a steering angle detection means, the output of the sensor is adjusted and determined so as to be a predetermined output value when the vehicle goes straight, thereby detecting the midpoint of the steering angle.

However, in the conventional steering angle detection means, the output value of the sensor corresponding to the center of the steering angle is determined in advance, and the characteristic values of the steering mechanisms such as camber and toe are changed according to the change over time and the maintenance of the steering mechanism. There was a problem in that a shift occurred between the determined output value and the midpoint of the steering angle for driving the vehicle straight, so that the midpoint could not be detected accurately.

Therefore, it is necessary to correct the output value of the sensor every fixed period or at the time of maintenance in order to eliminate the above-described variation and to accurately detect the center point.

The present invention has been made in view of the above circumstances, and it is determined that the vehicle is going straight when the steering torque is smaller than the torque setting value according to the vehicle speed and the torque fluctuation is small, the steering angle at that time is detected, and the center of gravity of the steering angle is detected accordingly. An object of the present invention is to obtain a steering angle center point detection device which makes it unnecessary to correct the output value of the center and improves the detection accuracy of the center point.

The apparatus for detecting a steering angle center point according to the present invention is a device for detecting a center point of a steering angle of a steering mechanism for converting a rotational movement of a vehicle steering wheel into a left-right direction, the vehicle speed detecting means for detecting a speed of a vehicle; A torque sensor for differentially detecting the steering torque applied to the steering wheel, a steering position detecting means for detecting the steering position of the steering mechanism, a steering torque setting value preset according to the detected vehicle speed, and a steering detected by the torque sensor A means for comparing the torque, a means for fertilizing the change amount set value with the torque sensor, a change amount of the steering torque in which the steering torque is smaller than the steering torque set value, and the amount of change in the steering torque is differentially detected, and a preset torque torque Steering angle at the steering position of the steering mechanism detected by the steering position detection means when less than the set value of change amount Characterized in that it comprises a means for detecting the midpoint of.

According to the present invention, the steering torque, the vehicle speed and the torque change amount are detected, and when the vehicle speed is larger than a predetermined value, the preset steering torque change value and the preset steering torque change amount set value are compared with the preset steering torque setting value according to the vehicle speed. And the steering torque change amount is compared with the magnitude of the steering torque change amount, and when the steering torque change value is smaller than the steering torque setting value and the steering torque change amount is smaller than the steering torque change amount setting value, it is regarded that the vehicle is going straight. Is detected.

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

1 is a partially broken front view of a one-pinion power steering apparatus using a steering angle center detection device according to the present invention, FIG. 2 is an enlarged sectional view taken along line II-II of FIG. 1, and FIG. 3 is a rotation of steering position detection means. It is an expanded sectional view along the III-III line | wire of FIG. 1 which shows the structure of a detector.

In the figure, "1" is a rack shaft, and is fixed to a part of the vehicle body in the longitudinal direction to the left and right, and is fitted inward to form the rack shaft case 2 having a cylindrical shape.

In addition, "3" is a pinion shaft and is supported by the pinion shaft case (4) which is installed in the vicinity of one end of the rack shaft case (2) in a state in which the shaft center is obliquely crossed with respect to the rack shaft (1). have.

The pinion shaft 3 has an upper shaft 3a and a lower shaft 3b connected to the same shaft through the torsion bar 5 as shown in FIG. 2, and the upper shaft 3a is connected to the pinion shaft case by the ball bearing 40. 4) It is supported inside, and its upper end is interlocked with a handle through a universal joint (not shown).

The lower shaft 3b is supported in the pinion shaft case 4 by a four-point contact ball bearing 41 at a position near the upper end in a state where the lower portion of the pinion shaft case 4 protrudes the lower portion of the pinion shaft case 4 to an appropriate length.

The above-mentioned four-point contact ball bearing 41 is fitted outwardly by the lower end side of the lower shaft 3b, and is formed at the end formed near the upper end of the lower shaft 3b, and is fitted on the outer circumferential surface by being fitted outside from the lower end side. Both sides of the inner circumference are held by the collar 42 to be positioned in the longitudinal direction on the outer side of the lower shaft 3b, and then inserted together into the pinion shaft case 4 from the lower opening described above together with the lower shaft 3b. Pinion shaft case 4 held by both ends of the outer circumference thereof by a ring-shaped portion formed under the case 4 and a lock nut 43 screwed into the case 4 in the opening described above. ) Is positioned inside the shaft in the axial length direction to bear the radial load acting on the lower shaft 3b and the axial load in both directions.

The pinion gear 30 is formed in the middle part of the lower shaft 3b which protrudes from the pinion shaft face 4 over the appropriate length in the axial length direction, and the pinion gear 30 is the pinion shaft case 4 Is fixed to the upper side of the above-described rack shaft case 2 by a fixing bolt 44, the shaft is positioned at a position near one end of the above-described rack shaft 1 in the rack shaft case 2. It engages with the rack gear 10 formed over the suitable length in the longitudinal direction, and engages with the lower shaft 3b and the rack shaft 1 in the state which inclined the shaft center to each other.

The lower shaft 3b described above extends further below the latching position with the rack shaft 1, and at the lower end thereof, a large bevel gear 31 is fitted to form a shaft like this and the gear forming surface downward. The bevel gear 31 is supported by a needle-shaped roller bearing 33 in a bevel gear housing 20 provided subsequent to the lower side of the rack shaft case 2.

Accordingly, the lower shaft 3b is supported at both sides of the engagement position between the rack gear 10 and the pinion gear 30 by the aforementioned four-point contact ball bearing 41 and the needle roller bearing 33, and the engagement thereof The amount of bending occurring in the lower shaft 3b at the position is kept within a predetermined allowable range.

In addition, in the engagement position between the rack gear 10 and the pinion gear 30, the rack guide 12 which presses the rack shaft 1 by the force of the push spring 11 toward the pinion shaft 3 so that they engage without a gap. Is installed, and the rack shaft 1 is supported in the engaged position at both ends in the radial direction at the rack guide 12 and the lower shaft 3b at the above-mentioned engagement position, and is installed in series with the pinion shaft case 4. It is supported by the bearing bush 13 inserted in the edge part of the rack shaft case 2 on the opposite side to a position, and the movement in the axial length direction is free in the rack shaft case 2 inside.

Tie rods (15) (15) (15) (15) (15) (15) (15) (15) (15), each of which connects the left and right ends of the rack (1), respectively protruding from both sides of the rack (2) case (2), to the left and right vehicle wheels (not shown). The vehicle wheels are steered left and right by movement in the axial length direction of the rack shaft 1.

"6" in FIG. 2 is a torque sensor for detecting steering torque applied to the handle, which is fitted outside the upper shaft 3a and rotates with the upper shaft 3a, centering on the shaft center of the upper shaft 3a on the lower end face. The resistor support member 60, which forms a ring-shaped resistor, and the outer shaft 3b, which are externally fitted, are rotated at the same time, and a detector is formed on the upper end face in contact with one of the radial points on the resistor described above. The potentiometer is constituted by the detector supporting member 61.

The upper shaft 3a of the pinion shaft 3 rotates around its axis in accordance with the rotation of the handle, but the road surface resistance acting on the wheel is acting on the lower shaft 3b through the rack shaft 1, and the torsion bar is sandwiched between the two shafts. In (5), twist occurs according to the steering torque applied to the handle.

The torque sensor 6 has a relative displacement in the circumferential direction between the upper shaft 3a and the lower shaft 3b as the torsion bar 5 twists as a potential corresponding to the position where the above-described detector and the resistor contact each other. In the case where the torsion bar 5 is not twisted, in other words, it is initially set to output a predetermined reference potential when the steering wheel operation is not performed.

The output signal of the torque sensor 6 is input to the control unit 7 in a timely manner, and the control unit 7 recognizes this signal as the direction and magnitude of the steering torque described above by comparing with the aforementioned reference potential and The drive signal is sent to the steering assistance motor (8).

The steering assist motor 8 is engaged with the electromagnetic clutch 16, the planetary gear reduction device 9, and the large bevel gear 31 described above, and has a lower diameter (below) through the bevel gear 32 having a smaller diameter. It transmits the rotational force to 3b).

The electromagnetic clutch 16 has a round ring shape and is coaxial with it on one side of the coil part 161 fixed to the middle case 81 of the motor 8 and the rotation shaft 80 of the motor 8 from the outside. The main body 162 rotates at the same time as the rotation shaft 80, and is engaged with the main body 162 by an electromagnetic force caused by energization of the coil unit 161 to face the main body 162. It is comprised by the desorption part 163, and desorption of the rotational force of the motor 8 is performed.

The planetary gear reduction device 9 is inserted into the detachable portion 163 and rotates and at the same time is supported by a bearing having one of the sun gears and one end thereof inserted into the main part and inserted into the planetary carrier 93 described later. The outer ring 91 and the outer ring 91 are formed in the form of a ring-shaped sun shaft 90 supported by the bearing, and a coaxial shaft fixed to the casing end face 82 of the motor 8 described above. A plurality of planetary gears 92 (rotating contact with the inner circumferential surface of the solar shaft and the outer circumferential surface of the solar gear 90 described above, respectively, rotating around a different shaft center and revolving around the axial center of the sun gear at the same time. 92)... And these planetary gears 92 and 92. It is composed of a planetary carrier 93 for supporting each shaft, has an outer diameter smaller than the motor 8 described above, and is integrated with the motor 8 and the electromagnetic clutch 16 on one side of the rotation shaft 80.

The output shaft 94 of the planetary gear reduction device 9 is fitted and fixed at the axial center position of the above-described planetary carrier 93 positioned on the same axis as the rotation shaft 80 of the motor 8 to protrude to a suitable length out of the casing. It is.

The small bevel gear 32 described above is fitted to the distal end of the output shaft 94 with the gear forming surface facing the front end side, and the small bevel gear 32 is the planetary gear 92 and the aforementioned 92 together with the output shaft 94. )… It is supposed to rotate according to the revolution of.

The motor 8, the electromagnetic clutch 16, and the planetary gear reduction device 9 described above have the small bevel gear 32 inward while the shaft center thereof is substantially parallel to the shaft center of the rack shaft 1. The small bevel gear 31 described above fits in one bevel gear housing 20 and fits inside the housing 20 to the large bevel gear 31 fitted to the lower end of the lower shaft 3b. It is fixed to the bracket 2a attached to the outer side of the main shaft case 2.

Backlash adjustment between the large bevel gear 31 and the small bevel gear 32 requires the casing of the planetary gear reduction device 9 and the bevel gear housing when the planetary gear reduction device 9 is inserted into the bevel gear housing 20. This can be easily done by changing the thickness and / or longevity of the shim inserted into the abutting contact portion with (20).

Further, on the other side of the rotational shaft 80 of the motor 8, a rotation detector 17 for detecting the rotational position of the motor 8 is fitted outside the rotational detector 17 on the other side of the rotational shaft 80 of the motor 8. A magnet plate 170 having a disc shape and having two poles of N poles and S poles, and two reed switches 171 attached to each other with a predetermined attachment angle β (β = 135 ° in this embodiment) ( 171).

4 is a waveform diagram showing an output waveform of the rotation detector. The two reed switches 171 and 171 are attached at an angle of attachment β of 135 ° so that the output waveform is output by being shifted in phase by 90 degrees.

Since each of the four waveforms is output in one revolution to detect the start and the end, the rotation detector 17 has a resolution of 1/16 of one revolution.

The rotation detector 17 can be detected at a rotational speed of zero compared to a conventional rotation detector such as a taco generator, and the relative position of the rotor can be detected.

Compared with the photointerrupter type rotary encoder, it is smaller, stronger against high temperature, less changeable over time, and lower in price. In addition, the output waveform becomes a pulse output, and the detection result is simply input to a CPU such as a microcomputer.

In addition to the output signal of the torque sensor 6 described above, the control unit 7 inputs the output signal of the rotation detector 17 and the output signal of the vehicle speed detector 18 for detecting the vehicle speed.

The control described later is performed by the controller 7 to output a drive signal for driving the motor 8 and the electromagnetic clutch 16.

Next, the control by the control unit 7 will be described.

5 is a block diagram showing the configuration and control operation of the controller 7.

The control part 7 mainly consists of a microprocessor, and is equipped with the drive circuit 72b of the electromagnetic clutch 16, the PWM drive circuit 72a of the motor 8, the current detection circuit 71e, etc.

)를 검출하는 각 가속도 검출부 (71b), 본 발명의 요지인 조향기구인 중점을 결정하기 위해서의 중점 검출부(71c), 모터(8)의 로크를 검출하는 로크 검출부(71f), 핸들의 회전 가속도(

)를 검출하는 각속도 검출부(71g) 밑 조향 토오크(T)의 절대값 ｜T｜에 따른 함수를 발생하는 토오크 함수부(73g)에 각각 입력되어 있다.The torque detection signal of the torque sensor 6 carries out the phase compensation part 71a for advancing the phase and stabilizing the system, and the acceleration of each rotation of the handle (

), The acceleration detection section 71b for detecting the center of gravity, the midpoint detection section 71c for determining the midpoint of the steering mechanism which is the gist of the present invention, the lock detection section 71f for detecting the lock of the motor 8, and the rotational acceleration of the handle (

) Are input to the torque function unit 73g which generates a function according to the absolute value | T | of the steering torque T under the angular velocity detection unit 71g.

The vehicle speed detection signal of the vehicle speed detector 18 includes a lock detector 71f, an instruction current function unit 73a, a midpoint detector 71c, a vehicle speed function unit 73f for generating a function corresponding to the vehicle speed v, and a correction current. Given by the function unit 73b and the change current function unit 73c, respectively.

)가 주어지고 각 가속도(

)와 차속(v)에 따라 모터(8)의 가감속시의 관성력과 차량의 바퀴 둘레의 관성력을 보정하는 보정 전류(Ic)를 결정한다.The correction current function unit 73b is used to calculate the acceleration of each handle (output from the respective speed detectors 71b).

) And the angular acceleration (

) And a correction current Ic for correcting the inertia force at the time of acceleration and deceleration of the motor 8 and the inertia force around the wheel of the vehicle according to the vehicle speed v.

The change current function 73c is given a steering angle steering angle θ output from the steering angle determining unit 71d to be described later, and the change current Ia which changes the characteristics of the instruction current I according to the steering angle θ and the vehicle speed. Determine.

The rotation detection signal of the rotation detector 17 is output from the lock detection section 71f, the midpoint detection section 71c, the angular acceleration detection section 71b, the angular velocity detection section 71g, and the rotation detection signal and the midpoint detection section 71c. It is input to the steering angle determination part 71d which determines steering angle (theta).

The lock detector 71f detects the rotation of the motor 8 when the torque and the vehicle speed are larger than the respective predetermined values based on the input rotation detection signal, the vehicle speed detection signal v and the torque detection signal T, thereby locking the lock. By detecting the presence or absence, the output signal is given to the electromagnetic clutch 16 through the drive circuit 72b.

The output ω of the acceleration detection unit 71g is given to an acceleration function unit 73d that generates a function according to the acceleration.

In addition, the function unit 73d is given a change current Ia and an offset amount is given in accordance with the change current Ia.

In addition, the command current function unit 73a which generates the command current I to the motor 8 is given the output signal T of the phase compensator 71a and the vehicle speed detection signal v and the change current Ia.

The output signal of the vehicle speed function unit 73f is given to the torque function unit 73g to output the torque function fd corresponding to the vehicle speed.

The output is given to the subtracted current function 73e and generates the subtracted current Ir by the output of the angular velocity function 73d and the output of the torque function 73g.

The output signal of the instructing current function unit 73g is input to the subtractor 74c, where the subtracted current Ir, which is the output of the subtracted current function unit 73e, is subtracted and the subtraction result is given to the adder 74a.

In the adder 74a, it is added with the output signal of the correction current function unit 73b, and the addition result is given to the subtractor 74b.

The subtractor 74b subtracts the feedback signal from the current detection circuit 71e which detects the current consumption of the motor 8 from the above addition result, and the subtraction result is PWM (Pulse-Width Modulation) pulse. It is given to the motor 8 through the furnace 72a.

Next, the operation will be described.

FIG. 6 is a flow chart showing the control of the lock detection, and in step 11 the vehicle speed of the vehicle speed detector 18 is determined in step 11 when it is judged whether or not a signal has started to be generated when the ignition switch (not shown) is turned on. Enter (v).

It is determined in step 12 whether the vehicle speed v is larger than the vehicle speed limit value Vs1, and when the vehicle speed v is large, the steering torque T of the torque sensor 6 is input in the next step 13.

It is determined in step 14 whether the steering torque T is greater than the torque limit value Ts1, and when it is large, the rotational position of the motor 8 in the rotation detector 17 is input in step 15, and the value is determined by step 16. If it is determined that the motor 8 is rotating, the motor 8 is returned. If the motor is not rotating, the motor 8 is locked. (8) and the planetary gear reduction device (9) are separated to free the steering mechanism from the motor (8). In step 18, the lock alarm (not shown) is turned on and returned.

On the other hand, when it is determined in step 10 that the signal has been started, the electromagnetic clutch 16 is turned off in step 19 and the motor 8 is turned on in step 20.

When the motor 8 is turned on, the elapse of the predetermined time is determined in step 21. Then, the rotation position of the motor 8 in the rotation detector 17 is input in step 22, and the motor 8 in step 23 is inputted by the value. When it is determined whether it is rotating or not, the motor 8 is turned off in step 24 and the electromagnetic clutch 16 is turned on in step 25.

When it is determined in step 23 that the motor 8 is not rotating, the lock alarm is turned on and returned in step 26.

Next, each acceleration detection and motor inertia control using the same will be described.

7 is a flowchart showing the calculation of each acceleration and the control of motor inertia using the same.

First, the torque T in the torque sensor 6 is input in step 30, and then in step 31, the rotation speed (ω m) of the motor 8 in the rotation detector 17 is measured in each acceleration detection section 71b. In step 32, each speed? Of the handle is obtained by the following operation.

Next, the inertia force of the motor 8 determined by the correction current function unit 73b and the inertia force of the wheel circumference of the vehicle are corrected by the angular acceleration ω and the vehicle speed V given to the steering wheel obtained in step 33. Find the correction current (IC).

Next, the correction current IC obtained in step 34 is input to the adder 72a and added with the indicating current I obtained by the indicating current function unit 73a.

Accordingly, since the inertia force of the motor 8 and the inertia force of the circumference of the vehicle wheel are added to the instructing current I when the respective accelerations such as the start and end of steering assistance by the motor 8 are detected, the steering current I is steered. Improvement of sense is planned.

Next, the calculation of the center point of the steering angle, which is the subject of the present invention, and the return control of the steering angle using the same will be described.

FIG. 8 is a flow chart showing the return control of the steering angle, FIG. 9 is the calculation of the midpoint of the steering angle, and FIG. 10 shows the procedure for determining the left and right positions of the steering angle.

11 is a graph showing the characteristics of the relationship between the motor current and the torque in the instruction current function unit 73a, and the instruction current I on the vertical axis and the torque T on the horizontal axis.

The dashed line indicates the characteristic when the vehicle speed is large, and the dashed-dotted line shows the characteristic when the vehicle speed is small.

In Fig. 8, the torque T is inputted in step 40 recently, and it is determined in step 41 whether the torque T is in the dead zone.

TS, T

-Ts의 범위에 있어서 공지의 모터 전류 제어를 행한다.If outside the dead zone, return and the T of FIG.

TS, T

Well-known motor current control is performed in the range of -Ts.

As a result, the indicating current I is determined according to the detection torque T and the detection speed V. FIG.

When the torque T is included in the dead zone, it is determined whether or not the midpoint calculation routine described later in step 42 has ended.

When the midpoint calculation is completed, the rotation position of the motor 8 is inputted from the rotation detector 17 in step 43, and then the relative steering angle θr and the midpoint θm based on the rotation position in step 44 are obtained. The steering angle determiner 71d determines the steering angle θ (= θ r -θ m).

When the steering angle θ is determined, the change current Ia is obtained from the change current drain 73c by the steering angle θ and the vehicle speed V in step 45, and the command current function 73a is used to determine the change of the current I. Calculate the value and direction.

When the midpoint operation is not completed in step 42, the change current Ia is inputted by the steering angle minimum value determined in the left and right determination routines described later in step 47 by inputting the rotation position of the motor 8 from the rotation detector 17 in step 46. ) Is calculated to calculate the value and direction of the indicated current (I).

In the midpoint calculation routine shown in FIG. 9, the vehicle speed V is input in step 50, and it is determined in step 51 whether the vehicle speed V is greater than the threshold value Vs2. (Ts2) is determined and the torque T is input in step 53, and it is determined in step 54 whether the torque T is smaller than the torque set value Ts2.

Ts)을 정하고, 다음에 토오크센서 (6)에 의해 검출된 최근의 토오크(Tn)와 그것보다 하나 앞의 타이밍에서 검출된 토오크(Tn-1)와의 토오크 차

T(=Tn-Tn-1)를 산출한다(스텝 542).When it is small, the torque difference set value (

Ts) is determined, and the torque difference between the latest torque Tn detected by the torque sensor 6 and the torque Tn-1 detected at a timing earlier than that.

T (= Tn-Tn-1) is calculated (step 542).

T)가 토오크차 설정값(

Ts)보다도 작은가 어떤가를 판정한다.Next, at step 543, the torque difference (

T) is the torque difference setpoint (

Or less than Ts).

When it is small, it is determined that the vehicle is going straight, and in step 551, the rotation position of the motor 8 is input and the relative steering angle θr is calculated (step 551).

Thus, the detected relative steering angle θr is integrated to the integrator having the transfer function 1 / (1 + Ts) (step 552), and then the counter is set to 0 by referring to the value of the counter installed in the controller 7 in step 553. If the midpoint cannot be determined otherwise, the counter is decremented (step 56), and the midpoint of the steering angle is updated (step 57).

If the counter value is 0, since the midpoint has already been determined, the steering angle determination flag is set in step 58, and the midpoint is updated in step 57.

This is to avoid unstable behavior early in the system.

T)가 토오크차 설정값(

Ts)보다 큰때는 리턴한다.In addition, when the vehicle speed V is smaller than the threshold value Vs2 in step 51, when the torque T is greater than the torque setting value Ts2 in step 54 or when the torque difference (

T) is the torque difference setpoint (

Returns greater than Ts).

As a result, when the torque T becomes zero, that is, when the torque T becomes zero, for example, when the hand is released at the time of returning the handle, it is not judged to be straight and the time for the midpoint calculation is shortened.

In addition, the return control is performed by the left and right determination routines described later until the midpoint calculation is completed.

In the right and left determination routine shown in FIG. 10, the vehicle speed V is input at step 60 to determine whether the vehicle speed V is greater than the threshold value Vs3 at step 61, and when the torque is large, the torque T is input at step 62. In step 63, the torque T is integrated and it is determined whether the direction of the integrated value is right.

If it is the right side, the value of the right side of the steering and minimum value is updated in step 65, and if it is the left side, the value of the left side of the steering angle minimum value is updated and returned in step 64.

The change current Ia is determined using this minimum value and the vehicle speed V.

On the other hand, when the change current Ia is determined by the steering angle θ and the vehicle speed V in the return control, as shown in FIG. 11, the steering wheel return control when the torque is in the dead zone according to the change current Ia. The indicated current I is changed.

For example, when the vehicle speed V is large, as indicated by the broken line, when the torque T enters the dead zone, the increase rate of the indicating current I is increased, and the motor 8 is controlled to speed up the return to the center point. On the contrary, when the vehicle speed is small, as indicated by the dashed-dotted line, when the torque T enters the dead zone, the motor 8 is controlled to reduce the increase rate of the instruction current I to slow the return to the center point.

Next, the angular velocity control of the handle will be described.

12 is a flowchart showing the angular velocity control of the handle.

Initially, the rotation position of the motor 8 is input by the output of the rotation detector 17 in step 70, and the relative steering angle (theta) r is calculated.

Next, in step 71, the steering angle θ (= θ r -θ m) is obtained from the relative steering angle θ r, and the offset amount corresponding to the steering angle θ is given to the angular velocity function unit 73d.

Next, in step 72, the vehicle speed V is input, and in step 73, the torque T is input.

Next, in step 74, the vehicle speed function fv is determined by the vehicle speed function unit 73f by the vehicle speed V, and the speed control amount fd is determined by the torque function unit 73g by this and the torque T.

)를 검출하여 오프셋량을 가미한 각속도 함수 (f

)를 구한다.Next, at step 75 the angular velocity (

) Angular velocity function (f) with offset

)

)와 속도 제어량(fd)에 의해 감산 전류(Ir)를 감산 전류 함수부(73e)에서 구하고, 이것을 감산기(74c)로 입력하여 그것에 의해 토오크(T) 및 각속도(

)에 따른 전류를 지시전류(I)에서 감산한다.Next, the angular velocity function f obtained in step 76

) And the subtraction current Ir are obtained from the subtraction current function unit 73e by the speed control amount fd and inputted to the subtractor 74c, whereby the torque T and the angular velocity (

) Is subtracted from the indicated current (I).

This improves the followability during sharp turning and prevents excessive return of the handle upon return.

In the present embodiment, the case where the device of the present invention is used for the return control of the steering wheel of the electric power steering apparatus has been described. However, the present invention is not limited to this and can be used for other control as well. In the present embodiment, the parallax difference of the detected torque is used as the change amount of the harmonic torque. However, the present invention is not limited to this, and the change amount may be any value as long as the change amount of the steering torque such as the derivative value can be detected. good.

In addition, in this embodiment, the rotation detector which detects the rotational position of the motor is used as the steering position detection means. Any means may be used.

As described above, according to the present invention, the steering torque, the vehicle speed, and the angular velocity are detected, and the steering position of the steering mechanism is detected when the steering torque is smaller than the preset steering torque setting value according to the vehicle speed and the torque difference is smaller than the torque difference setting value. Since the center of gravity of the steering mechanism is detected by one steering position, the center of gravity can be detected at the relative steering position, the calibration of the center of gravity of the steering position detection means is not necessary, and the accuracy of the center of gravity detection can be improved, As we judge whether we go straight by torque car in comparison with prior application (Japanese special place 63-248309), we do not let go of steering wheel at the time of steering wheel return and judge immediately before torque becomes zero, and friction of road surface It is hard to be affected by, and it has an excellent effect such as shortening the computation time of the key operation.

Claims (1)

An apparatus for detecting the center of the steering angle of a steering mechanism for converting the rotation of the steering wheel of the vehicle into a left-right direction for steering, the vehicle speed detecting means 18 for detecting the speed of the vehicle and steering applied to the steering wheel The torque sensor 6 which sequentially detects torque, the steering position detection means 17 which detects the steering position of a steering mechanism, the steering torque setting value preset according to a vehicle speed, and the steering torque detected by the torque sensor are compared A comparison means for comparing the change amount of the steering torque sequentially detected by the torque sensor 6 with a preset torque change amount set value, and a steering torque change smaller than the steering torque set value and the change amount of the steering torque set the torque change amount Detecting means for detecting the midpoint of the steering angle at the steering position of the steering mechanism detected by the steering position detecting means 17 when smaller than the value ( A steering angle focus detection device characterized in that it comprises a 71c).

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