KR102311493B1 - Torque Sensor And Method for Processing Torque Signal - Google Patents

Abstract

The present invention relates to a torque sensor having high reliability and a torque signal processing method, wherein the torque sensor of the present invention outputs a main digital signal (T1), a first sub digital signal (T2), and a second sub digital signal (T3). and the slope of the second sub digital signal T3 is 1/2 of the slope of the main digital signal T1.

Description

Torque Sensor And Method for Processing Torque Signal

The present invention relates to a torque sensor and a torque signal processing method.

The driver manipulates the steering wheel connected to the wheel to control the driving direction of the vehicle. And, in order to accurately measure the degree of steering of the steering wheel, a power steering device is further provided between the steering wheel and the wheel to measure the torque applied to the steering shaft.

An electric power steering (Motor Driven Power Steering; MDPS) system includes a torque sensor, and measures the torque applied to the steering shaft by measuring the mutual magnetic field of the rotor coupled to the steering shaft. Then, the motor is driven by determining the operating force required to steer the vehicle according to the torque.

Specifically, the electric power steering system receives an analog voltage output from the torque sensor, compares the main signal T1 and the sub-signal T2 , and performs arithmetic processing to detect an output error of the torque sensor. That is, when T1 or T2 is not correct, the electric power steering system operates using the remaining signals.

1 is a general torque output graph, and FIG. 2 is a general torque signal processing flowchart.

As shown in FIG. 1 , the electric power steering system adds up T1 and T2 within a predetermined range, and when the summation result is a predetermined value, it operates using the torque output using T1 and T2.

As shown in FIG. 2 , in the general electric power steering system, when T1 and T2 are input from the torque sensor (S10), T1 and T2 are summed to confirm the summing result (S15). When the summation result matches the preset value, torque is output using T1 and T2 (S20). Conversely, if the result of the sum of T1 and T2 does not match the set value, it is sequentially checked whether T1 and T2 are within a certain range (S25, S30, S35, S40, S45, S50) and a warning lamp is turned on (S55, S60, S55, S60, S65, S70).

However, in this case, there is a problem in that it is not possible to accurately determine which signal among T1 and T2 is defective or normal. Currently, as the vehicle functional safety-related standards are being strengthened, a torque sensor having high reliability is required.

Republic of Korea Patent Publication No. 10-2011-0109100 (published on Oct. 6, 2011)

An object of the present invention is to solve the above problems, and to provide a torque sensor and a torque signal processing method having high reliability.

To achieve the above object, the torque sensor of the present invention outputs a main digital signal T1, a first sub digital signal T2, and a second sub digital signal T3, and The slope is 1/2 of the slope of the main digital signal T1.

In addition, the torque signal processing method of the present invention for achieving the same object comprises the steps of comparing the summation result of the main digital signal (T1) and the first sub digital signal (T2) output from a torque sensor with a preset value; and when the summing result and the preset value do not match, an abnormal output of the main digital signal T1 and the first sub digital signal T2 is detected using the second sub digital signal T3. including the steps of

The torque sensor of the present invention includes three of T1 which is a main digital signal (Torque Sensor Master; TSM), T2 which is a first sub digital signal (Torque Sensor Slave; TSS1), and T3 which is a second sub digital signal (Torque Sensor Slave; TSS2). outputs a signal. And by processing the torque signal using the output T1, T2, and T3, it is possible to improve the reliability of the electric power steering system.

1 is a general torque output graph.
2 is a flowchart of a typical talk signal processing.
3 is a perspective view of a torque sensor of the present invention.
4 is a torque output graph of the present invention.
5 is a flowchart of a talk signal processing according to the present invention.

Since the present invention may have various changes and may have various embodiments, specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the embodiment of the present invention to a specific embodiment, and it should be understood to include all changes, equivalents, or substitutes included in the spirit and scope of the embodiment.

Terms including an ordinal number, such as first, second, etc., may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the embodiments of the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the possibility of addition or existence of numbers, steps, operations, components, parts, or combinations thereof.

In the description of the embodiment, in the case where one component is described as being formed "on or under" of another component, above (above) or below (below) (on or under) includes both components in which two components are in direct contact with each other or in which one or more other components are disposed between the two components indirectly. In addition, when expressed as "on or under", the meaning of not only an upward direction but also a downward direction based on one component may be included.

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components are assigned the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted.

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

Figure 3 is a perspective view of the torque sensor of the present invention, Figure 4 is a torque output graph of the present invention.

3, the torque sensor of the present invention includes a steering shaft 10 including an input shaft 10a and an output shaft 10b, a torque rotor 20, a position rotor 30, a magnetic field detection unit 40, and a control unit (not shown). city) and upper and lower housings 50a and 50b. The torque sensor as described above may output a torque by measuring a rotation angle deviation between the steering wheel and the wheel.

When the driver manipulates the steering wheel, the input unit 10a connected to the steering wheel rotates, and the output unit 10b connected to the input unit 10a also rotates to transmit rotational force to the wheel. However, in general, the input unit 10a rotates more than the output unit 10b due to the road friction force of the wheels. Accordingly, the wheel can be rotated using a power means such as a motor using the torque output by the torque sensor.

Specifically, the input shaft 10a passes through the upper housing 50a and is positioned at the center of the torque rotor 20 . And, the output shaft 10b passing through the lower housing 50b is coupled to the input shaft 10a through a torsion bar (not shown) in the center of the torque rotor 20 . The torque rotor 20 is accommodated in the position rotor 30 , and the torque rotor 20 is rotatable in the position rotor 30 . Although not shown, a ring-shaped magnet is provided on the outer peripheral surface of the torque rotor 20 , and a magnet is provided on the inner surface of the position rotor 30 , and when the input unit 10a rotates, the torque rotor 20 and the position rotor 30 ), there is a change in the magnetic field between

The magnetic field detection unit 40 includes a plurality of IC chips (not shown) to detect a change in the magnetic field due to a deviation between the rotation angle of the input shaft 10a and the rotation angle of the output shaft 10b. Then, the magnetic field detector 40 transmits the sensed magnetic field change to a controller (not shown), and the controller (not shown) generates a torque based on the magnetic field change. Then, the motor (not shown) generates auxiliary power based on the torque and transmits it to the steering shaft 10 .

The magnetic field change is output as T1 which is a main digital signal (Torque Sensor Master; TSM), T2 which is a first sub digital signal (Torque Sensor Slave; TSS1), and T3 which is a second sub digital signal (Torque Sensor Slave; TSS2). In this case, T1 and T2 are electrical signals that sense the relative rotational displacement of the input shaft 10a and the output shaft 10b according to the rotation of the steering wheel. And, T3 is a signal having a slope of 1/2 of the slope of T1.

The reason that the torque sensor of the present invention outputs three signals T1, T2 and T3 is to additionally use T3 in the torque signal processing algorithm. That is, when the electric power steering system operates with one signal when the signal of T1 or T2 fails, it is to improve reliability compared with T3 whether the signal for operating the electric power steering system is a normal signal.

Specifically, as shown in FIG. 4 , the torque sensor of the present invention includes T1 which is a main digital signal (Torque Sensor Master; TSM), T2 which is a first sub digital signal (Torque Sensor Slave; TSS1), and a second sub digital signal as described above. It outputs T3 which is a signal (Torque Sensor Slave; TSS2). At this time, when T1 and T2 satisfy the preset reference value, it is determined as normal. For example, the normal range for T1 and T2 is from 0.5V to 4.5V. And, T3 is output using the slope of T1, and the slope of T3 is 1/2 of the slope of T1. T3 is determined to be normal when it has a range of 1.5V to 3.5V.

The torque sensor of the present invention as described above may calculate T1 and T2 using T3, and may detect a torque error by comparing the calculated T1 and T2 with T1 and T2 output from the torque sensor.

T1 and T2 are calculated using T3 as in Equations 1 and 2 below.

[Equation 1]

T1 = 2 x (T3 - 2.5) + 2.5

[Equation 2]

T2 = -2 x (T3 - 2.5) + 2.5.

Hereinafter, the torque signal processing algorithm of the present invention will be described in detail.

5 is a flowchart of a talk signal processing according to the present invention.

In the present invention, when the torque cannot be output through T1 and T2, the torque is output with only one signal selected from among T1, T2 and T3, or the torque is output with T1 and T3 or T2 and T3. Torque is output using the torque constants of T1, T2, and a torsion bar. The torque constant of the torsion bar is when the torque is normally output (torque constant: K ₁ ), when the torque is output using only T1 (torque constant: K ₂ ), when the torque is output using only T2 (torque constant: K ₃ ) and the case of outputting torque only with T3 (torque constant: K ₄ ) have different values, respectively.

As shown in FIG. 5 , when T1, T2, and T3 are input from the torque sensor (S100), T1 and T2 are summed to check whether the summation result matches a preset value (S105). In the present invention, when the sum of T1 and T2 output from the torque sensor is 5V, torque is output using T1 and T2 (S110).

Conversely, if the summing result is not 5V, perform the next step.

First, it is checked whether T1 is within 0.5V to 4.5V (S115, S120), and it is checked whether T1 is normally output.

A case where T1 is within the normal range (0.5V to 4.5V) and a case outside the normal range will be separately described as follows.

*when T1 is in the normal range*

If T1 is within the normal range, perform the following steps in sequence.

First, it is checked whether T3 is 1.5V to 3.5V (S125, S130). When T3 is within the normal range, it is checked whether T1 ≠ 2 x (T3 - 2.5) + 2.5, and a step of comparing T1 calculated by T3 and output T1 is performed (S135). If the T1 calculated by T3 and the output T1 match, it is checked that T2 ≠ -2 x (T3 - 2.5) + 2.5, and a step of comparing T2 calculated by T3 with the output T2 is further performed ( S140). When the T2 calculated by T3 and the output T2 match, the step of checking whether T2 is 0.5V to 4.5V is performed (S145, S150).

And, when it is determined that T2 outputs the normal range by steps S145 and S150, T1, T2, and T3 all output the normal range, but the summation result of T1 and T2 is incorrect. and a warning lamp for turning off the MDPS is turned on (S155).

Conversely, in step S140, if T2 calculated by T3 and output T2 do not match, it is determined that T3 is also defective and torque is output using only T1 (S160). If T2 calculated by T3 coincides with output T2, but it is determined that T2 outputs an abnormal range in steps S145 and S150, torque is output only with T1 and T3 (S165). At this time, the torque is output using only T1 and T3, and the torque constant uses a torque constant K _{1 in} a steady state in which the sum of T1 and T2 matches a preset value.

[Equation 3]

Torque = 4K ₁ x (T1 - T3)

Then, in steps S125 and S130 of checking whether T3 is 1.5V to 3.5V, if T3 is not in the normal range, the step of checking whether T2 is 0.5V to 4.5V is immediately performed (S145, S150). Then, according to the result of the steps S145 and S150, the torque is output by performing the step S155 or the step S165.

*If T1 is not in the normal range*

If T1 is not within the normal range through steps S115 and S120, the following steps are sequentially performed.

First, it is checked whether T2 is within 0.5V to 4.5V (S170, S175), and in turn, it is checked whether T3 is also within the normal range.

Specifically, when T2 is in the normal range, it is checked whether T3 is 1.5V to 3.5V (S180, S185). If T2 and T3 are within the normal range, check whether T2 ≠ -2 x (T3 - 2.5) + 2.5, and perform a step of comparing T2 calculated by T3 with output T2 (S190), Ensure the reliability of the output.

If T2 calculated by T3 matches with output T2, torque is output only with T2 and T3 (S195). _{In this case, as the torque constant, a torque constant K 1 in} a steady state in which the sum of T1 and T2 matches a preset value is used.

[Equation 4]

Torque = 4/3K ₁ x (T3 - T2)

Conversely, when T2 calculated by T3 and output T2 do not match, T2 is determined to be defective and torque is output using only T3 ( S200 ). Then, T2 is in the normal range, but when T3 is in the abnormal range through steps S180 and S185, torque is output using only T2 (S205).

Conversely, when it is confirmed that T2 is in the abnormal range through steps S170 and S175, it is checked whether T3 is 1.5V to 3.5V (S210, S215). For example, when T3 is within the normal range, only T3 is determined to be normal and torque is output using only T3 (S200). Then, when T3 is in the abnormal range, it is determined that all of T1, T2, and T3 have failed, and a warning lamp for turning off the MDPS is turned on (S220).

That is, the torque signal processing method of the present invention includes T1 which is a main digital signal (Torque Sensor Master; TSM), T2 which is a first sub digital signal (Torque Sensor Slave; TSS1), and a second sub digital signal (Torque Sensor Slave; TSS2). T3 is outputted, and T1 or T2 output abnormally can be easily detected by using T3. Accordingly, it is possible to prevent the driver from directly applying a large force to steering due to a malfunction of the motor by generating auxiliary power with a normal signal selected from among T1, T2, and T3.

In addition, when T1 or T2 is abnormally output and the electric power steering system operates with the remaining signals, it may be checked whether the remaining signals for operating the electric power steering system are normal signals using T3. Accordingly, the present invention can improve the reliability of the electric power steering system.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is known in the art to which the present invention pertains that various substitutions, modifications and changes are possible within the scope without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

10a: input axis 10b: output axis
10: steering shaft 20: torque rotor
30: position rotor 40: magnetic field detection unit
50a: upper housing 50b: lower housing

Claims (10)

delete delete delete comparing the summation result of the main digital signal T1 and the first sub digital signal T2 output from the torque sensor with a preset value; and
When the summing result and the preset value do not match, the ratio of the main digital signal T1 to the first sub digital signal T2 using the second sub digital signal T3 output from the torque sensor A torque signal processing method comprising the step of detecting a normal output. 5. The method of claim 4,
calculating the main digital signal (T1) using the second sub-digital signal (T3), and comparing the calculated main digital signal with the output main digital signal (T1) How to process a torque signal. 5. The method of claim 4,
calculating the first sub digital signal T2 using the second sub digital signal T3 and comparing the calculated first sub digital signal with the output first sub digital signal T2; Torque signal processing method further comprising. 5. The method of claim 4,
When the main digital signal T1 outputs an abnormal signal,
A torque signal processing method, characterized in that the torque calculated by the following Equation (3) is output using the first sub-digital signal (T2) and the second sub-digital signal (T3).
[Equation 3]
Torque = 4K x (T1 - T3)
where K is the torque constant 5. The method of claim 4,
When the first sub digital signal T2 outputs an abnormal signal,
A torque signal processing method, characterized in that the torque calculated by the following Equation (4) is output using the main digital signal (T1) and the second sub-digital signal (T3).
[Equation 4]
Torque = 4/3K x (T3 - T2)
where K is the torque constant 9. The method according to any one of claims 4 to 8,
The torque signal processing method, characterized in that the slope of the second sub digital signal (T3) is 1/2 of the slope of the main digital signal (T1). 10. The method of claim 9,
The main digital signal T1 and the second sub digital signal T3 satisfy Equation 1 below,
[Equation 1]
T1 = 2 x (T3 - 2.5) + 2.5
The first sub-digital signal (T2) and the second sub-digital signal (T3) satisfy the following equation (2).
[Equation 2]
T2 = -2 x (T3 - 2.5) + 2.5

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