KR101687684B1

KR101687684B1 - Steering system

Info

Publication number: KR101687684B1
Application number: KR1020150161354A
Authority: KR
Inventors: 김건하; 김진우
Original assignee: 만도헬라일렉트로닉스(주)
Priority date: 2015-11-17
Filing date: 2015-11-17
Publication date: 2016-12-20

Abstract

A steering system is disclosed. According to an embodiment of the present invention, the steering system comprises: a sensor unit outputting a plurality of signals in correspondence to at least one rotation of an input shaft and an output shaft; and an electromagnetic control unit receiving the signals outputted from the sensor unit, individually calculating a difference value between a previous angle value and a current angle value of each signal with respect to at least two signals of the received signals, calculating a representative difference value with the calculated difference values, and calculating a steering angle combining the calculated representative difference value and a previous steering angle to be a final steering angle.

Description

Steering system {STEERING SYSTEM}

The present invention relates to a steering system, and more particularly, to a steering system for sensing a steering angle of a steering wheel in response to an operation of a steering wheel of a vehicle.

Generally, the steering angle signal is transmitted to a parking assist system (SPAS) as well as a driving safety device such as a steering system, an electronic stability control (ESC), a steering collision avoidance system (SCAs) ), Driver's convenience systems such as Smart Cruise Control (SCC), and the like.

The steering angle sensor used to calculate the steering angle serves to convert a physical signal into an electrical signal to an electronic control unit (ECU) so as to calculate the steering angle information of the driver mounted on the steering system.

In recent years, reliability of the output signal has been demanded as the use range of the steering angle signal becomes wider. To secure this, it is necessary to secure the reliability using the redundant structure in the steering system.

Korean Patent Laid-Open Publication No. 2013-0084133 (published on July 24, 2014)

An embodiment of the present invention is to provide a steering system capable of enhancing the reliability of a steering angle by utilizing a dynamic redundancy structure in calculating a steering angle of a steering wheel of a vehicle.

According to an aspect of the present invention, there is provided a control apparatus for a vehicle including: a sensor unit for outputting a plurality of signals corresponding to rotation of at least one of an input shaft and an output shaft; And a controller configured to receive a plurality of signals output from the sensor unit and calculate a difference angle between a previous angle value and a current angle value of each signal with respect to at least two of the plurality of received signals, An electronic control unit for calculating a representative difference angle using the angles, and calculating the final steering angle by summing the calculated representative difference angle and the previous steering angle.

The electronic control unit may calculate the representative difference angle by averaging at least two difference angles among the calculated difference angles, or may calculate any one of the calculated difference angles by the representative difference angle.

The electronic control unit may calculate the representative difference angle with respect to the difference angle within a predetermined error range by comparing the calculated difference angles with each other.

According to another aspect of the present invention, there is provided a torque angle sensor comprising: a torque angle sensor; And an electronic control unit for receiving an output signal of the torque angle sensor, wherein the torque angle sensor comprises: a first rotor connected to the input shaft; a second rotor connected to the output side; a first signal corresponding to a rotation angle of the input shaft A second angle element for outputting a second signal corresponding to a rotation angle of the first rotor and a third signal corresponding to a rotation angle of the second rotor, And a third angle element outputting a corresponding fourth signal and a fifth signal corresponding to a rotation angle of the second rotor, wherein the electronic control unit controls the signals output from the first to third angular elements Calculates a difference angle between a previous angle value and a current angle value of each signal for at least two of the four signals received from the second and third angle elements, There is a steering system for calculating a difference between each represents, and calculates the final steering angle by adding the previous angle and the steering angle representing the calculated difference can be provided using.

The electronic control unit may further comprise a vernier algorithm for inputting the first signal received from the first angle element at the start of the vehicle and the four signals received from the second and third angle elements The final steering angle can be calculated.

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1 is a configuration diagram of a steering system according to an embodiment of the present invention.
2 is a diagram for explaining a vernier algorithm performed in an electronic control unit of a steering system according to an embodiment of the present invention.
3 is a diagram for explaining an algorithm in which a vernier algorithm and an angle tracking algorithm are combined in an electronic control unit of a steering system according to an embodiment of the present invention.
FIG. 4 illustrates a method of calculating four steering angle signals by applying a dynamic redundancy structure in steering angle calculation in an electronic control unit of a steering system according to an embodiment of the present invention, and then obtaining a final steering angle signal using a majority voting system FIG.
5 is a view for explaining the calculation of the final steering angle signal using the majority voting system after obtaining four steering angle differences by applying a dynamic redundancy structure in the steering angle calculation in the electronic control unit of the steering system according to another embodiment of the present invention to be.
Figs. 6 and 7 are diagrams showing the results of the simulation according to Figs. 4 and 5. Fig.
8 to 13 are views for explaining various aspects of a sensor unit in a steering system according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments to be described below are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. The present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components are exaggerated for the sake of convenience. Like reference numerals designate like elements throughout the specification.

In the following description of the present embodiment, the torque angle sensor of the present invention is limited to an input shaft coupled with a steering shaft and three angular elements that output a signal corresponding to a rotation angle of the output shaft. It is not necessary to output a signal corresponding to the rotation angle of all the output shafts nor is it limited to having three angular elements. The torque angle sensor can be applied to a case in which a plurality of signals corresponding to the rotation angle of the sensing object are outputted even if the signal corresponding to the rotation of any one of the input shaft and the output shaft is output without having three angle elements.

Hereinafter, the sensor unit for outputting a signal corresponding to the rotation angle of the steering shaft will be described as a torque angle sensor using a contactless inductive position sensor system and a Hall sensor system. However, And the sensor portion may have various types of sensing elements instead of the basic angular element of the torque angle sensor, as will be described later.

1 is a configuration diagram of a steering system according to an embodiment of the present invention.

Referring to FIG. 1, the steering system may be coupled to a steering shaft including a steering wheel 11, an input shaft 12, a torsion bar 13, and an output shaft 14.

When the driver rotates the steering wheel 11, the rotational force of the steering wheel 11 is transmitted through the input shaft 12, the torsion bar 13, and the output shaft 14, and the direction of the steering wheel is changed.

The torsion bar 13 is disposed between the input shaft 12 and the output shaft 14 and can coaxially connect the input shaft 12 and the output shaft 14. [ The torsion bar 13 can measure the degree of twist generated in the input shaft 12 and the output shaft 14.

The steering system includes a torque angle sensor 100 that modulates a torque sensor and a steering angle sensor into one, and an electronic control unit (ECU) 110 that calculates and outputs a steering angle based on a signal sensed by the torque angle sensor 100 do.

The torque angle sensor 100 includes a first rotor 101 connected to the input shaft 12, a second rotor 102 connected to the output shaft 14, a gear 103 rotated in conjunction with the input shaft 12, A first angle element 105 for converting a magnetic flux density change of the magnet 104 into an electrical signal and outputting the electrical signal, a first rotor 101 and a second rotor 101, And a second angle element 106 and a third angle element 107 for outputting physical position information on which the first and second angles 102 and 102 rotate.

The first angle element 105 may be a Hall IC. The first angle element 105 can output a signal corresponding to the rotation angle of the input shaft 12. [

The second angle element 106 and the third angle element 107 may be a contactless inductive position sensor ASIC (CIPOS ASIC).

The second angle element 106 outputs a signal corresponding to the rotation angle of the first rotor 101 and a signal corresponding to the rotation angle of the second rotor 102.

The third angle element 107 outputs a signal corresponding to the rotation angle of the first rotor 101 and a signal corresponding to the rotation angle of the second rotor 102.

The electronic control unit 110 receives the respective signals output from the first to third angular elements 105 to 107 and calculates and outputs the steering angles of the steering wheel 11 using the received signals .

A signal used for the steering angle calculation in the torque angle sensor 100 is one angle information outputted from the first angle element 105 and two angle information outputted from the two angle elements 106 and 107, Signal.

In the CIPOS system, a CIPOS ASIC, which means a position sensing system using a non-contact electromagnetic induction system, converts the physical position information of the rotors 101 and 102 located on the same axis into electrical signals when the steering system rotates, .

The Hall IC converts the magnetic flux density change of the magnet 104 located on the rotating shaft into an electrical signal and transmits the electrical signal to the electronic control unit 110.

The torque angle sensor 100 transmits the angle information to the electronic control unit 110 so that the electronic control unit 110 can perform the final steering angle calculation.

The electronic control unit 110 calculates the steering angle using the transmitted angle information.

In the past, the signal used for the steering angle calculation uses a total of two angular information for each one output from the two Hall ICs.

There are two methods of calculating the steering angle, one using Vernier algorithm and the other using Vernier algorithm and Angle follower.

The Vernier algorithm is a method of calculating a combination of two signals having different phases of a repeated angle (or a repetition angle of a signal). For example, one of the four signals output from the second and third angular elements 106 and 107 (CIPOS ASIC) and one signal output through the first angular element 105 (HALL IC) are combined and operated.

2 is a diagram for explaining a vernier algorithm performed in an electronic control unit of a steering system according to an embodiment of the present invention.

Referring to FIG. 2, the Primary (from CIPOS) graph at the top of FIG. 2 represents a selected one of the four signals from the second and third angular elements 106 and 107 (CIPOS ASIC) The graph represents one signal (PWM signal) output through the first angle element 105 (Hall IC).

If the steering angle of the signal output from the CIPOS ASIC is 40˚ and the steering angle of the signal output from the HALL IC is 296˚, input the steering angle 40˚ of the signal output from the CIPOS ASIC and the steering angle 296˚ of the signal output from the HALL IC The steering angle signal calculated by the vernier algorithm module shown in FIG. 2 is expressed by the angle signal graph at the bottom of FIG. 2, and its steering angle is 1476 degrees.

3 is a diagram for explaining an algorithm in which a vernier algorithm and an angle tracking algorithm are combined in an electronic control unit of a steering system according to an embodiment of the present invention.

Referring to FIG. 3, in the case of using the angular tracking algorithm in combination with the vernier algorithm, which is another method of calculating the steering angle, for one of the two signals used for the steering angle calculation, The output value is compared to obtain a difference value (Delta angle), and the difference value is added to the existing steering angle value and added.

In this method, since the initial value of the steering angle can not be obtained, the current position of the steering wheel is obtained using the venerable algorithm at the first moment when the vehicle starts, and thereafter, the calculation is performed using the angle tracking algorithm.

At least four identical steering angle values can be simultaneously computed through angular tracking calculation using difference value calculation using one or more signals of the four signals output from the second and third angular elements 106 and 107 (CIPOS ASIC) Do. This means having at least four dynamic redundancy structures.

More specifically, first, the electronic control unit 110 determines whether it is an initial state. That is, it is determined whether the vehicle is in the initial state in which the vehicle is turned on.

In the initial state, the electronic control unit 110 performs a vernier angle calculation. That is, the Vernier algorithm is applied to one of the four signals output from the second and third angular elements 106 and 107 (CIPOS ASIC) and one signal output through the first angular element 105 (HALL IC) And the calculated angle is determined as the steering angle phi n.

On the other hand, if it is not the initial state, an absolute angle obtained by adding the difference angle ?? to the previously calculated steering angle? N-1 is determined as the steering angle? N. At this time, the difference angle [Delta] [theta] is calculated for each of the four signals output from the second and third angular elements 106 and 107 (CIPOS ASIC) signal) ([theta] n). For reference, four difference angles are generated by calculating the difference angle (??) for four signals, and four absolute angles are obtained by adding the previous steering angle (? N-1) to each difference angle. And determines it as the current steering angle phi n. For example, the average angle of the four absolute angles can be determined as the current steering angle phi n.

A widely used method for ensuring the reliability of a signal is a redundancy check.

This redundant structure can be classified into a static redundant structure and a dynamic redundant structure.

In the case of static redundancy, the output is determined by a majority voting system for inputs with parallel structures. In the static redundancy structure, a determination is made as to whether or not the signal is used through comparison of signals within the system.

In this static redundant structure, the input is interdependent. If a fault is detected in one input, the signal may not be used depending on the setting of the voting system.

In case of dynamic redundancy, it is composed of parallel structure. It is similar to static redundancy structure in that voting system is used, but input signal is independent, so even if a fault is detected in one input, And can be replaced according to judgment conditions.

As described above, in order to secure the reliability of the steering angle calculation, it is important to secure a redundant structure. In particular, in the case of a dynamic redundant structure, even if an anomaly occurs in one signal through the combination of independent signals, reliability of the final steering angle signal can be ensured through combination of other identical signals.

In the past, only the vernier algorithm is used for the steering angle calculation, so that only one steering angle signal is calculated using the two signals.

On the other hand, in the embodiment of the present invention, since the vowel algorithm and the angle tracking algorithm are applied in combination, four independent signals can be used for the calculation, so that the reliability of the signal can be secured through the majority voting system of the steering angle signal dynamic redundant structure have.

FIG. 4 illustrates a method of calculating four steering angle signals by applying a dynamic redundancy structure in steering angle calculation in an electronic control unit of a steering system according to an embodiment of the present invention, and then obtaining a final steering angle signal using a majority voting system FIG.

Referring to FIG. 4, an independent steering angle signal can be obtained by obtaining respective difference angles (difference angles 1 to 4) through one input signal (angle information 1 to 4), and adding previous steering angle signals to each of the difference angles The final steering angle signal can be obtained using a voting system.

More specifically, in the case of the angular information 1 received from the second angular element 106, the electronic control unit 110 calculates the difference value between the previous angular value of the received angular information 1 and the current angular value 1), and calculates the steering angle signal 1 by adding the calculated difference angle to the previous steering angle.

In the case of the angular information 2 to the angle information 4, the steering angle signal 2 to the steering angle signal 4 are calculated by applying the same method as the angle information 1.

The final steering angle signal is calculated using the majority voting system for the four calculated steering angle signals. For example, the final steering angle is calculated by averaging at least two steering angles among the four steering angles. Further, any one of the four steering angles can be calculated as the final steering angle signal.

Meanwhile, the four steering angles may be compared with each other to determine whether they are within a predetermined error range, and a steering angle obtained by averaging steering angles within any predetermined error range or within a predetermined error range may be calculated as a final steering angle.

In such an arithmetic structure, there is a dynamic redundancy structure through four independent signals, so that the reliability of the steering angle signal can be secured.

However, in this method, since the angle tracking operation must be performed four times at the same time, the calculation load of the electronic control unit 110 performing the actual calculation can be increased, and a method for improving the calculation load is needed.

Therefore, an improved method for reducing the load of the angular tracking operation is required in the method of identifying the redundant structure as shown in FIG.

5 is a view for explaining the calculation of the final steering angle signal using the majority voting system after obtaining four steering angle differences by applying the dynamic redundancy structure in the steering angle calculation in the electronic control unit of the steering system according to another embodiment of the present invention to be.

Referring to FIG. 5, the difference angle obtained through the four input signals is an independent value as in the case of each of the steering angle signals obtained through the angle tracking operation, and can be utilized in the majority voting system.

More specifically, in the case of the angular information 1 received from the second angular element 106, the electronic control unit 110 calculates the difference value between the previous angular value of the received angular information 1 and the current angular value 1).

Similarly, in the case of the angular information 2 to the angular information 4, the same method as in the angle information 1 is used to calculate the difference angles (Delta angle 2 to Delta angle 4).

The representative difference angle is calculated using the majority voting system for the four calculated difference angles (Delta angle 1 to Delta angle 4). For example, a representative difference angle is calculated by averaging at least two difference angles among four difference angles. In addition, any one of the four difference angles can be calculated as the representative difference angular signal. On the other hand, the four difference angles are compared with each other to determine whether the difference angle is within a predetermined error range, and a difference angle obtained by averaging the steering angles within one of the difference angles within a predetermined error range or within a preset error range is calculated as a representative difference angle can do.

After calculating the representative difference angle, the steering angle obtained by summing the calculated difference angle and the previous steering angle is calculated as the final steering angle.

The advantage of this method is that each of the four difference angles is independent of each other, so that it is possible to calculate the steering angle with reliability even if only one angle tracking operation is performed while maintaining the dynamic redundant structure.

The difference voting system according to the embodiment of the present invention has an advantage of reducing a calculation load on a microcontroller unit (MCU) compared to a steering angle voting system.

Figs. 6 and 7 are diagrams showing the results of the simulation according to Figs. 4 and 5. Fig.

Referring to FIGS. 6 and 7, the data used in the simulation is obtained by rotating the actual sensor. The obtained sensor output does not have a structure that can directly determine the difference angle, so a conversion process is required. This is not included in the calculation process time, but the simulation of the processing time for the difference angle and only the calculation of the final steering angle signal is performed.

The simulation results show that the processing time increases according to the number of data basically. The method of voting by using the steering angle signal and the method of voting by using the difference angle signal are the same. However, It was confirmed that there was a gain for the processing time of about 1 ms.

According to an embodiment of the present invention, four steering angle signals can be obtained through a vernier operation and an angle tracking operation using a torque angle sensor, and the reliability of signals can be secured by utilizing a dynamic redundancy structure for the signals.

Also, according to the embodiment of the present invention, it is possible to utilize a lot of redundant structures due to the structure of the torque angle sensor, and it is easy to ensure reliability with respect to the steering angle signal.

According to the embodiment of the present invention, the steering angle signal can be obtained only by comparing the difference angles in order to reduce the load due to the redundant calculation. In this case, the load on the calculation can be reduced without loss of the dynamic redundant structure of the signal have.

8 to 13 are views for explaining various aspects of a sensor unit in a steering system according to another embodiment of the present invention.

Referring to FIG. 8, the sensor unit 100 may include two angle elements HALL IC 1 and HALL IC 2 instead of the torque angle sensor. At this time, each Hall IC can output a signal corresponding to the rotation angle of at least one of the input shaft 12 and the output shaft 14 of the steering shaft. The sensor unit 100 further includes the first rotor 101 and the second rotor 102. The HALL IC 1 transmits a signal corresponding to the rotation angle of the first rotor 101 to the HALL IC 2 Can output a signal corresponding to the rotation angle of the second rotor 102. [

The electronic control unit 110 can calculate the final steering angle by applying the final steering angle calculation according to FIG. 4 or the final steering angle calculation according to FIG. 5 to the two signals received from the sensor unit 100.

9 shows a case where the sensor unit 100 includes one HALL IC and a CIPOS ASIC that outputs one signal corresponding to the rotation angle of the first rotor 101 or the second rotor 102. [

FIG. 10 is a schematic view of a sensor unit 100 in which the sensor unit 100 includes one HALL IC and one CIPOS ASIC, as shown in FIG. 9, in which the CIPOS ASIC is connected to each of the first rotor 101 and the second rotor 102, Are outputted together.

11 shows a case where the sensor unit 100 includes two CIPOS ASICs, and each CIPOS ASIC outputs one signal corresponding to the rotation angle of each of the rotors 101 and 102.

FIG. 12 shows a case where two CIPOS ASICs are included as shown in FIG. 11, and each CIPOS ASIC outputs signals corresponding to angles of rotation of the first rotor 101 and the second rotor 102 together.

13 shows a case in which one HALL IC and two CIPOS ASICs are included, and two CIPOS ASICs output one signal corresponding to the rotation angle of the first rotor 101 or the second rotor 102. Fig.

9 to 13, in the same way as in FIG. 8, the electronic control unit 110 performs a final steering angle calculation according to FIG. 4 or a final steering angle calculation according to FIG. 5 for at least two signals among a plurality of signals received from the sensor unit 100 The final steering angle can be calculated.

100: Torque angle sensor 101: First rotor
102: second rotor 105: first angle element
106: second angle element 107: third angle element
110: Electronic control unit

Claims

A sensor unit for outputting a plurality of signals corresponding to rotation of at least one of an input shaft and an output shaft; And
And calculates a difference angle between a previous angle value and a current angle value of each signal with respect to at least two signals among the plurality of received signals, And an electronic control unit for calculating a final steering angle by summing the calculated representative difference angle and the previous steering angle.

The method according to claim 1,
Wherein the electronic control unit calculates the representative difference angle by averaging at least two difference angles among the calculated difference angles or calculates any one of the calculated difference angles as the representative difference angle.

3. The method of claim 2,
And the electronic control unit calculates the representative difference angle with respect to the difference angle within a predetermined error range by comparing the calculated difference angles with each other.

Torque angle sensor; And
And an electronic control unit for receiving an output signal of the torque angle sensor,
Wherein the torque angle sensor comprises:
A first rotor connected to the input shaft, a second rotor connected to the output side, a first angle element outputting a first signal corresponding to a rotation angle of the input shaft, a second signal corresponding to a rotation angle of the first rotor, A third signal corresponding to a rotation angle of the first rotor, and a third signal corresponding to a rotation angle of the second rotor, Comprising an angle element,
Wherein the electronic control unit receives the signals output from the first to third angular elements and for each of at least two of the four signals received from the second and third angular elements, And calculates a difference angle between the current angle value and the current angle value, calculates a representative difference angle using the calculated difference angles, and calculates the final steering angle by summing the calculated representative difference angle and the previous steering angle.

5. The method of claim 4,
The electronic control unit uses a Vernier algorithm in which the first signal received from the first angle element at the start of the vehicle and the four signals received from the second and third angle elements are input A steering system for calculating a final steering angle.

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