KR20080010275A - Apparatus for sensing steering angle and sensing method of the same - Google Patents

Abstract

An apparatus and a method for detecting a steering angle are provided to increase a processing speed by removing an existing signal conversion process and reduce the manufacturing cost by removing an A/D converter. An apparatus for detecting a steering angle comprises a main gear(210) rotating together with a steering shaft(100), and first and second auxiliary gears(221,225). The first and second auxiliary gears engage with the main gear and have gear ratios different from each other. First and second magnets(231,235) are meshed with the first and second auxiliary gears to rotate together with the first and second auxiliary gears, respectively. First and second rotary hall integrated circuits(241,245) detect rotation angles of the first and second magnets, respectively. A member calculates an absolute steering angle of the steering shaft according to output signals of the rotary hall integrated circuits.

Description

Steering angle sensing device and sensing method {APPARATUS FOR SENSING STEERING ANGLE AND SENSING METHOD OF THE SAME}

1 is a view showing a steering angle sensing device according to an embodiment of the present invention.

2 is a flowchart showing a steering angle sensing method according to an embodiment of the present invention.

3 is a view illustrating a steering angle sensing method according to an exemplary embodiment of the present invention, and a graph of digital output values obtained by sensing rotation angles of first and second magnets in first and second rotary hole integrated circuits, respectively.

FIG. 4 is a graph illustrating only an area of δS ≧ 0 shown in FIG. 3;

5 is a flowchart showing a steering angle sensing method according to another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: steering shaft 210: main gear

221,225: 1st and 2nd auxiliary gear 231,235: 1st and 2nd magnet

241,245: first and second rotary hole integrated circuit

The present invention relates to a steering angle sensing device and a sensing method.

The steering device used in a vehicle is a device for changing the direction of a steering wheel (front wheel or rear wheel) in order to change the traveling direction of the vehicle in operation. Since the steering degree of the driving vehicle is utilized as data for controlling the vehicle, the steering angle of the steering shaft is measured to detect the steering degree of the vehicle.

Conventional steering angle sensing device detected a steering angle in a 360 ° range based on one rotation of the steering shaft. However, since the steering wheel of the vehicle rotates 2 to 3 rotations in the clockwise direction and 2 to 3 rotations in the counterclockwise direction, it is not known at all how much the steering wheel has been rotated by the conventional steering angle sensing device. Due to this, there is a problem that the absolute angle of the steering shaft is unknown.

In order to solve such a problem, a steering angle sensing device using an anisotropic magnetorresistance (AMR) device has been developed, which will be described in detail.

In the steering angle sensing device using the AMR element, two subgear gears of different sizes are engaged with the main gear which rotates in the same manner as the steering shaft. The magnets are fixed to the two sub-gears, respectively, and two AMR elements sense the positions of the magnets and represent the analog voltage values. The analog-to-digital converter then converts the analog voltage values into digital values and detects the absolute angle of the steering wheel through the combination and operation of these converted values.

However, in the conventional steering angle sensor as described above, an error may occur during conversion in the analog-to-digital converter, and thus there is a disadvantage in that reliability is lowered.

In addition, there is a disadvantage in that the processing speed is delayed because a process of converting an analog value to a digital value is required.

In addition, since an analog-digital converter is required, the cost increases.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to provide a steering angle sensing device and method that can improve the reliability.

Another object of the present invention is to provide a steering angle sensing device and method for improving the processing speed as well as reducing the cost.

Steering angle sensing device according to the present invention for achieving the above object, the main gear to rotate with the steering shaft; First and second auxiliary gears having different gear ratios that rotate in association with the main gear; First and second magnets respectively coupled to the first and second auxiliary gears and rotating together with the first and second auxiliary gears, respectively; First and second rotary hall integrated circuits for sensing digital rotation angles of the first and second magnets to output digital signals; Means for calculating an absolute steering angle of the steering shaft in accordance with output signals of the first and second rotary hole integrated circuits.

In addition, the steering angle sensing method according to the present invention for achieving the above object, the first and second rotary hole integrated circuit (Rotary) the rotation angle of the first and second magnets rotate at different angular speeds as the steering shaft rotates; Sensing using a Hall Integrated Circuit); Obtaining a difference δS between the rotation angle S1 of the sensed first magnet and the rotation angle S2 of the second magnet sensed; The rotation angle θ of the steering shaft is calculated using Equation δS x G (gain value).

Hereinafter, a steering angle sensing device and a sensing method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a steering angle sensing device according to an embodiment of the present invention.

As shown, the steering angle sensing device according to the present embodiment includes the main gear 210, the first and second auxiliary gears 221 and 225, the first and second magnets 231 and 235, and the first and second rotary hole integrated circuits. (Rotary Hall Integrated Circuit) (241, 245).

The main gear 210 is coupled to the outer circumferential surface of the steering shaft 100 that rotates according to an external force for rotating the steering wheel (not shown) and rotates together with the steering shaft 100.

The first and second auxiliary gears 221 and 225 mesh with and interlock with the main gear 210. In this case, the gear ratio of the first sub-gear 221 and the gear ratio of the second sub-gear 225 are formed different from each other, hereinafter, the gear ratio of the second sub-gear 225 is greater than the gear ratio of the first sub-gear 221. Assume Then, when the main gear 210 rotates one turn, the first auxiliary gear 221 rotates more than the second auxiliary gear 225.

The first and second magnets 231 and 235 are coupled to the first and second auxiliary gears 221 and 225, respectively, and rotate in the same manner as the first and second auxiliary gears 221 and 225, respectively.

The first and second rotary hole integrated circuits 241 and 245 are installed to face the first and second magnets 231 and 235, respectively, to sense rotation angles of the first and second magnets 231 and 235. The first and second rotary hole integrated circuits 241 and 245 sense a change in magnetic flux according to the rotation of the first and second magnets 231 and 235 and output the value as a digital signal.

The main gear 210 may be directly coupled to the steering shaft 100, or may be coupled to the steering shaft 100 using the steering torque sensing device 300 as a medium. The steering torque sensing device 300 is connected to the steering shaft 100 and rotates together with the steering shaft 100. The main gear (300) is connected to the output shaft 310 of the steering torque sensing device 300 coupled to the steering shaft 100. 210 is combined. In order to couple the main gear 210 and the output shaft 310, protrusions 213 and grooves 313 are inserted into and interposed between the inner circumferential surface of the main gear 210 and the outer circumferential surface of the output shaft 310.

The first and second auxiliary gears 221 and 225 are coupled to and supported by the case 350 of the steering torque sensing device 300, and the first and second rotary hole integrated circuits 241 and 245 are the case of the steering angle sensing device. Connected to PCB 260 coupled to 250.

The steering angle sensing device according to the present embodiment is provided with means for calculating an absolute steering angle of the steering shaft 100 using digital signal values output from the first and second rotary hole integrated circuits 241 and 245.

The means is represented by equation (1).

θ = δS × G, and 0 ≦ δS ≦ (2 ⁿ −1).

At this time, δS = S1-S2, θ is the rotation angle of the main gear 210, G is the gain value, n is the number of bits of the rotary hole integrated circuit. In addition, S1 is a rotation angle of the first magnet 231 sensed and output by the first rotary hole integrated circuit 241, and S2 is a second magnet sensed and output by the second rotary hole integrated circuit 245. 235) the rotation angle.

A method of sensing a steering angle by the above Equation 1 will be described with reference to FIGS. 1 to 4.

2 is a flow chart illustrating a steering angle sensing method according to an embodiment of the present invention, Figure 3 is a view for explaining a steering angle sensing method according to an embodiment of the present invention, the rotation angle of the first and second magnets FIG. 4 is a graph showing digital output values sensed by the first and second rotary hole integrated circuits, and FIG. 4 is a graph illustrating only an area of δS ≧ 0 illustrated in FIG. 3.

As shown, the steering angle sensing method according to the present embodiment senses the rotation angle of the main gear 210 that rotates in the same manner as the steering shaft 100 to measure the rotation angle of the steering shaft (100).

To this end, in step S110, the rotation angles of the first and second magnets 231 and 235 that rotate in the same manner as the first and second auxiliary gears 221 and 225 that rotate in conjunction with the main gear 210 may be determined. 2 are sensed using the rotary hole integrated circuits 241 and 245. The first and second rotary hole integrated circuits 241 and 245 output rotation angles of the first and second magnets 231 and 235 as digital values.

It is assumed that the steering wheel and the steering shaft 100 and the main gear 210 rotate by 1,800 ° when the steering wheel is rotated as much as possible in the counterclockwise direction while the steering wheel is rotated as much as possible in the clockwise direction. In addition, it is assumed that the first and second auxiliary gears 221 and 225 interlocked with the main gear 210 while having different gear ratios are eight revolutions and 7.5 revolutions. Gear ratios of the first and second auxiliary gears 221 and 225 may be appropriately designed according to the actual rotation angle of the main gear 210 according to the vehicle and the precision to be sensed. Then, as the main gear 210 rotates, the rotation angles of the first and second magnets 231 and 235 sensed by the first and second rotary hole integrated circuits 241 and 245 are waveform S1 as shown in FIG. 3. And waveform S2. At this time, the maximum value of the output is 2 ⁿ , where n is the number of bits of the rotary hole integrated circuit.

In operation S120, the difference δS between the output value S1 sensed by the first rotary hole integrated circuit 241 and the output value S2 sensed by the second rotary hole integrated circuit 245 is calculated. The value of δS is the value of the area shaded to the left in FIG. 3. At this time, since the period of the waveform S1 is shorter than the period of the waveform S2, the value of δS becomes (−) in the region shaded to the right in FIG. 3. If the value of δS is negative, the rotation angle θ degree of the main gear 210 to be calculated is a value of (−). This is cumbersome because a new reference value must be set for the negative value.

In order to solve this problem, it is determined in step S130 that? S ≧ 0 is applied. Thus, if δS≥0, θ is calculated (S140), if δS <0, S1 + 2 ⁿ = S1 is calculated (S133), and fed back to step S120 to calculate δS of the positive value. .

The rotation angle of the main gear 210 is θ = δS x G, where G is a pre-calculated gain value.

When the value of δS changes linearly, there is no overlapping value of δS, and when there is no overlapping value of δS, there is no overlapping value of θ. In order not to cause duplication of θ values, 0 ≦ δS ≦ (2 ⁿ −1) should be used.

In the condition of 0≤δS, δS may be obtained by S1 + 2 ⁿ of S1 of the region hatched to the right in FIG. 3 where the value of δS is negative. Therefore, the condition of 0≤δS also corresponds to a condition for causing the value of δS to change linearly.

When the area of δS≥0 and δS are negative (-), and the area of δS newly obtained by S1 + S1 + 2 ⁿ is extracted, as shown in FIG. 4, as the main gear 210 rotates from 0 ° to 1800 °, δS varies linearly between 0 and (2 ⁿ −1). That is, there is no overlapping value of δS.

The steering angle sensing device and the sensing method according to the present embodiment rotate in conjunction with the main gear 210 which rotates in the same manner as the steering shaft 100, but the rotation angles of the first and second magnets 231 and 235 that rotate at different periods from each other. Is sensed by the first and second rotary hole integrated circuits 241 and 245 which output digital signals, and the difference is obtained to obtain the absolute steering angle of the steering shaft 100. That is, since the steering angle is sensed using the digital signal directly output, the reliability is improved and the processing speed is high.

FIG. 5 is a flowchart illustrating a steering angle sensing method according to another exemplary embodiment of the present invention, and describes only differences from FIG. 2.

As shown, in step S130, if δS≥0, the new δS is calculated (S133) with δS + ²ⁿ = δS (n = number of bits of the rotary hole integrated circuit), and then θ is calculated ( S140).

As described above, the steering angle sensing device according to the present invention senses the first and second rotary hole integrated circuits outputting digital angles of rotation angles of the first and second magnets rotating at different periods in cooperation with the steering shaft. Then, the difference is found and the absolute steering angle of the steering shaft is obtained. Therefore, since there is no process of converting an analog signal into a digital signal, an error occurrence phenomenon due to signal conversion is eliminated and reliability is improved.

In addition, the processing speed is improved because there is no signal conversion process, and the cost is reduced because no analog / digital converter is required.

In the above, the present invention has been described in accordance with one embodiment of the present invention, but those skilled in the art to which the present invention pertains have been changed and modified without departing from the spirit of the present invention. Of course.

Claims (7)

A main gear rotating together with the steering shaft; First and second auxiliary gears having different gear ratios that rotate in association with the main gear; First and second magnets respectively coupled to the first and second auxiliary gears and rotating together with the first and second auxiliary gears, respectively; First and second rotary hall integrated circuits for sensing digital rotation angles of the first and second magnets to output digital signals; And means for calculating an absolute steering angle of the steering shaft in accordance with output signals of the first and second rotary hole integrated circuits. The method of claim 1, The means is Equation θ = δS x G, 0≤δS≤ (2 ⁿ -1), where S1 is the rotation angle of the first magnet sensed and output by the first rotary hole integrated circuit, S2 is the The rotation angle of the second magnet sensed and output by the second rotary hole integrated circuit, δS = S1-S2, θ is the rotation angle of the main gear, G is a gain value, n is the number of bits of the rotary hole integrated circuit. ⁿ is a steering angle sensing device for calculating the absolute steering angle of the steering shaft according to the maximum value of the digital output signal of the rotary hole integrated circuit. The method of claim 1, The main gear is coupled to the steering shaft is coupled to the outer peripheral surface of the output shaft of the steering torque sensing device that rotates in the same way as the steering shaft, A steering angle sensing device having protrusions and grooves interposed between the inner circumferential surface of the main gear and the outer circumferential surface of the output shaft. Sensing the rotation angles of the first and second magnets rotating at different angular velocities as the steering shaft rotates using the first and second rotary hall integrated circuits; Obtaining a difference δS between the rotation angle S1 of the sensed first magnet and the rotation angle S2 of the second magnet sensed; The steering angle sensing method of performing a step of calculating the rotation angle (θ) of the steering shaft by using the equation δS x G (gain value). The method of claim 4, wherein If δ S <0, Equation S1 = S1 + 2 ⁿ (n = number of bits of the rotary hole integrated circuit, 2 ⁿ is the maximum value of the digital output signal of the rotary hole integrated circuit) Steering angle sensing method characterized in that the feedback (Feed Back). The method of claim 4, wherein If δS <0, the equation δS = δS + 2 ⁿ (n = number of bits in the rotary hole integrated circuit, 2 ⁿ is the maximum value of the digital output signal of the rotary hole integrated circuit), and then convert δS to calculate θ. Steering angle sensing method characterized in that. The method according to claim 5 or 6, Steering angle sensing method, characterized in that δS satisfies Equation 0≤δS≤ (2 ⁿ -1).

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