Signal correction device and method for steer-by-wire system

Abstract

A signal correction device and method for an SBW system are provided. The signal correction device may include: a command signal receiving / transmitting unit for receiving a command signal transmitted from a superior device via a vehicle communication network and transmitting a command signal obtained by correcting the linearity of the received command signal to a subordinate device via the vehicle communication network; a buffer unit for storing the command signal received by the command signal transmitting / receiving unit as an original signal; and a control unit for correcting the linearity of the original signal using the original signal stored as the command signal in the buffer unit and a command signal obtained by delaying the command signal stored in the buffer unit by a specified unit time, thereby generating a command signal with corrected linearity. The signal correction device and method for an SBW system disclosed herein can maintain the linearity of a signal.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a signal correction device and method for a Steer-By-Wire (SBW) system, and more particularly to a signal correction device and method for an SBW system capable of correcting a signal received by a receiving unit from a transmitting unit via a vehicle communication network in a vehicle employing the SBW system, thereby maintaining the linearity of the signal. Background Art

[0002] Generally speaking, the SBW system refers to a new generation of chassis control technology, in which a control unit (not shown) controls a motor (e.g., a reaction motor or a steering motor) to steer the front wheels based on input of a steering signal detected by a sensor unit (not shown) without the need for a mechanical connection such as a universal joint between the steering wheel and the steering device.

[0003] More specifically, the SBW system detects signals such as steering angle and steering torque required by the driver's steering request from a steering wheel (not shown) via a sensor unit (not shown) and transmits the detected signals to a control unit (not shown). The control unit then generates a steering reaction force and a steering force control signal based on a preset control algorithm. These signals drive a reaction motor (not shown) connected via a vehicle communication network (or ideally, a Controller Area Network (CAN) communication) to provide the driver with a steering reaction force similar to that of existing power steering systems. Simultaneously, the control unit drives a steering motor (not shown) via the vehicle communication network to steer the vehicle left or right.

[0004] Therefore, when the mechanical column is removed from the SBW system, the system transmits the steering angle command to the steering actuator via the vehicle communication network. As a result, road vibrations transmitted from the road along the mechanical connection are prevented from being transmitted to the driver, improving road feel.

[0005] However, the possible problems of SBW system are: due to the characteristics of vehicle communication network, such as Figure 1 As shown, among signals transmitted through a vehicle communication network (eg, CAN communication), a signal that needs to maintain linearity (eg, a steering angle signal) does not maintain the linearity of the received signal, but may experience delays or peaks.

[0006] Therefore, when a signal that needs to remain linear does not remain linear but has a delay or a peak, for example, when a steering angle signal that needs to remain linear does not remain linear but has a delay or a peak, in the portion where the steering angle signal has a delay or a peak, the steering is not smooth but unstable.

[0007] Therefore, a method is needed to correct a signal to maintain linearity without using a filter.

[0008] A related art of the present disclosure is disclosed in Korean Patent Application Publication No. 10-2011-0062119, published on June 10, 2011, and entitled “Control Apparatus and Method for SBW System”. Summary of the Invention

[0009] Various embodiments of a signal correction apparatus and method for an SBW system can correct a signal received by a receiving unit from a transmitting unit via a vehicle communication network in a vehicle to which the SBW system is applied, thereby maintaining the linearity of the signal.

[0010] In one embodiment, a signal correction device of an SBW system may include: a command signal receiving / transmitting unit for receiving a command signal sent by an upper-level device through a vehicle communication network, and sending a command signal obtained by correcting the linearity of the received command signal to a lower-level device through the vehicle communication network; a buffer unit for storing the command signal received through the command signal transmitting / receiving unit as an original signal; and a control unit for correcting the linearity of the original signal by using the original signal stored as the command signal in the buffer unit and a command signal obtained by delaying the command signal stored in the buffer unit by a specified unit time to generate a command signal with corrected linearity.

[0011] The upper-level device can send a command signal at the upper level through the vehicle communication network according to the command signal transmission system specified by the SBW system; and the lower-level device can receive a command signal at the lower level through the vehicle communication network according to the command signal transmission system specified by the SBW system.

[0012] The signal correction device may further include a counting signal transmitting / receiving unit configured to receive a counting signal transmitted by the upper-level device and transmit the counting signal to the lower-level device.

[0013] The signal correction device can separately send / receive the counting signal in synchronization with the command signal received through the vehicle communication network to check the period and linearity of the command signal, and the counting signal continuously increases to a specified specific count value at each specified unit time of each period.

[0014] The control unit may determine whether linearity of the command signal received through the vehicle communication network is maintained by using a count value of a count signal.

[0015] In order to judge whether the linearity of the command signal is maintained, the control unit may judge whether a delay or a peak occurs by using a count value of the count signal in each cycle.

[0016] The control unit may check a count value of the count signal received in synchronization with the instruction signal in each cycle, and judge that the instruction signal is delayed when the same count value as that of the previous cycle remains even in the current cycle.

[0017] When the command signal has no delay, the control unit may generate a command signal to be transmitted to a lower device by using the command signal delayed by one unit time of the corresponding cycle.

[0018] When the instruction signal is delayed, the control unit may generate an instruction signal to be transmitted to a lower device by using the original signal of the corresponding period.

[0019] The control unit may check a count value of the count signal received synchronously with the command signal in each cycle, and determine that a peak value has appeared in the command signal when a count value doubled from a count value in a previous cycle is detected in the current cycle. When a peak value has not appeared in the command signal, the control unit may generate a command signal to be transmitted to a lower-level device by using the command signal delayed by one unit time in the corresponding cycle.

[0020] When a peak appears in the command signal, the control unit may generate a command signal to be transmitted to a lower-level device by using only half of an increment of the original signal in the corresponding period.

[0021] In one embodiment, a signal correction method for an SBW system may include: receiving, by a control unit of a signal correction device of the SBW system, an instruction signal from an upper-level device; storing, by the control unit, the instruction signal as an original signal in a buffer unit; determining, by the control unit, whether the linearity of the instruction signal is maintained; and when the linearity of the instruction signal is not maintained, correcting, by the control unit, the linearity of the original signal by using the original signal stored as the instruction signal in the buffer unit and an instruction signal obtained by delaying the instruction signal stored in the buffer unit by a specified unit time, to generate an instruction signal with corrected linearity.

[0022] In the judgment of whether the linearity of the instruction signal is maintained, the control unit can check the count value of the count signal received synchronously with the instruction signal in each cycle, and when the same count value as the previous cycle is retained even in the current cycle, judge that the instruction signal is delayed.

[0023] In order to correct the linearity of the original signal, when the command signal has no delay, the control unit may generate a command signal to be transmitted to a lower device by using the command signal delayed by one unit time in the corresponding cycle.

[0024] In order to correct the linearity of the original signal, when the instruction signal is delayed, the control unit may generate an instruction signal to be transmitted to a lower device by using the original signal of the corresponding period.

[0025] In the determination of whether the linearity of the instruction signal is maintained, the control unit may check the count value of the count signal received synchronously with the instruction signal in each cycle, and when a count value doubled from the count value of the previous cycle is detected in the current cycle, determine that a peak appears in the instruction signal.

[0026] In order to correct the linearity of the original signal, when no peak appears in the command signal, the control unit may generate a command signal to be transmitted to a lower device by using the command signal delayed by one unit time in the corresponding cycle.

[0027] In order to correct the linearity of the original signal, when a peak appears in the command signal, the control unit may generate the command signal to be transmitted to the lower device by using only half of the increment of the original signal in the corresponding period.

[0028] According to an embodiment of the present disclosure, a signal correction device and method of an SBW system can correct a signal received by a receiving unit from a transmitting unit through a vehicle communication network in a vehicle to which the SBW system is applied, thereby maintaining the linearity of the signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a diagram for describing a case of a conventional SBW system in which the linearity of a signal received through a vehicle communication network is not maintained due to a delay or a peak occurring in the signal.

[0030] Figure 2 2 is a diagram showing a schematic configuration of a signal correction device of an SBW system according to an embodiment of the present disclosure.

[0031] Figure 3 is a flowchart describing a signal correction method for an SBW system according to an embodiment of the present disclosure.

[0032] Figure 4 is used to describe Figure 3 A diagram of the method used to correct the linearity of the command signal.

[0033] Figure 5 is a graph showing a difference between a signal whose linearity is not corrected and a signal whose linearity is corrected by applying a signal correction method of an SBW system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] The following describes a signal correction device and method for a SBW (steer-by-wire) system using various exemplary embodiments with reference to the accompanying drawings. It should be noted that the drawings are not drawn to exact scale, and that the thickness of lines or the dimensions of components may be exaggerated for ease of description and clarity. Furthermore, the terms used herein are defined with regard to the functionality of the present invention and may vary based on the user's or operator's preferences or intentions. Therefore, the definitions of terms should be interpreted in light of the overall disclosure set forth herein.

[0035] Figure 2 2 is a diagram showing a schematic configuration of a signal correction device of an SBW system according to an embodiment of the present disclosure.

[0036] like Figure 2 As shown, a signal correction device of an SBW (steer-by-wire) system according to an embodiment of the present disclosure includes a command signal sending / receiving unit 110 , a counting signal sending / receiving unit 120 , a control unit 130 and a buffer unit 140 .

[0037] The command signal sending / receiving unit 110 receives a command signal (e.g., a steering angle command) sent by an upper-level device (not shown), which may be, for example, a device that sends a command signal at an upper level through a vehicle communication network according to a specified command signal transmission system.

[0038] Further, the command signal sending / receiving unit 110 sends the command signal (e.g., steering command) obtained by correcting the linearity of the received command signal to a downstream device (not shown), which is, for example, a device that receives the command signal at a downstream level through a vehicle communication network according to a specified command signal transmission system.

[0039] The control unit 130 corrects the linearity of the command signal received by the command signal receiving / transmitting unit 110 (see Figure 3 and Figure 4 ).

[0040] At this time, in order to correct the linearity of the instruction signal (or original signal), the control unit 130 stores the instruction signal (or original signal) received through the instruction signal sending / receiving unit 110 in the buffer unit 140, and uses the instruction signal and the original signal delayed by a specified unit time (for example, 1 millisecond) from the original signal, that is, the instruction signal stored in the buffer unit 140 and not delayed by one unit time.

[0041] The count signal transmitting / receiving unit 120 receives a count signal transmitted from an upper device (not shown) that transmits a command signal at an upper level through a vehicle communication network according to a specified command signal transmission system, for example, and transmits the count signal to a lower device.

[0042] The counting signal refers to a signal that is separately sent / received to check the period and linearity of a command signal received through a vehicle communication network (eg, CAN communication) and increases by a specified specific value 1 in each period (ie, a specified unit time).

[0043] The control unit 130 can use the count value of the count signal to determine whether the period and linearity of the current communication signal are maintained. For example, in order to determine whether the linearity of the command signal or the original signal is maintained, to determine the portion of the command signal or the original signal where the linearity is not maintained, or to determine whether a delay or peak occurs in the command signal or the original signal, the control unit 130 uses a count signal that increases by 1 in each period (i.e., a specified unit time).

[0044] The control unit 130 determines a portion where linearity is not maintained or a delay or a peak occurs based on the count value of the count signal, and corrects the portion where linearity is not maintained or a delay or a peak occurs in the command signal or the original signal by using a command signal delayed by a specified unit time (e.g., 1 millisecond) in each cycle (i.e., a specified unit time) and the original signal, i.e., the command signal stored in the buffer unit 140 and not delayed by a unit time (see Figure 3 and Figure 4 ). Figure 3 is a flowchart describing a signal correction method for an SBW system according to an embodiment of the present disclosure, and Figure 4 is used to describe Figure 3 A diagram of the method used to correct the linearity of the command signal.

[0045] refer to Figure 3 The control unit 130 stores the instruction signal received from the upper device through the instruction signal sending / receiving unit 110 in the buffer unit 140, and generates an instruction signal to be sent to the lower device, that is, in step S101, by using the instruction signal stored in the buffer unit 140 and delayed by one unit time (for example, 1 millisecond) to generate an instruction signal that is delayed by one unit time but whose linearity has been corrected.

[0046] The control unit 130 checks the count value of the count signal that is synchronized with the instruction signal or the original signal and received separately in each cycle (i.e., a specified unit time), and when the same count value as that of the previous period is maintained in the current cycle, for example, when the count value of the previous cycle is 10 and the count value of the current cycle is 10, it is judged that the instruction signal is delayed (yes in step S102).

[0047] Thus, when the command signal is not delayed (No in S102), the control unit 130 generates a command signal to be sent to the lower device (i.e., a command signal whose linearity is corrected or whose value is delayed by one unit time) by using the command signal delayed by one unit time (e.g., 1 millisecond) in the corresponding cycle, and in step S103 (see Figure 4 )middle.

[0048] On the other hand, when the command signal is delayed (Yes in step S102), the control unit 130 generates a command signal to be transmitted to the lower-level device (i.e., a command signal which is not delayed by one unit time but whose linearity has been corrected) by using the original signal in the corresponding cycle (i.e., the command signal which is stored in the buffer unit 140 and is not delayed by one unit time or the original signal value), and in step S103 (see Figure 4 )middle.

[0049] The control unit 130 checks the count value of the count signal in each cycle (i.e., a specified unit time), which is synchronized with the instruction signal or the original signal and is received independently, and when it is detected in the current cycle that the count value increases by 2 compared with the count value in the previous cycle, for example, when the count value of the previous cycle is 10 and the count value of the current cycle is 12, it is judged that a peak has appeared in the instruction signal (yes in step S105).

[0050] Thus, when no peak appears in the command signal (No in step S105), the control unit 130 generates a command signal to be transmitted to the lower-level device (i.e., a command signal delayed by one unit time but having its linearity corrected) by using a command signal delayed by one unit time (e.g., 1 millisecond) from the corresponding cycle or a value of the command signal delayed by one unit time, in step S103 (see Figure 4 ).

[0051] On the other hand, when a peak occurs in the command signal (Yes in step S105), the control unit 130 generates a command signal to be sent to the lower device (i.e., a command signal delayed by one unit time but with its linearity corrected) by half the increment of the original signal in the corresponding cycle (i.e., the command signal stored in the buffer unit 140 and not delayed by one unit time), and in step S107 (see Figure 4 ). When only half of the original signal increment is used, it may mean that a value obtained by halving the increment is used because the increment of the original signal is 2. While transmitting / receiving a command signal between an upper device and a lower device via a vehicle communication network (e.g., CAN communication) during driving, steps S101 to S107 are continuously repeated.

[0052] The vehicle communication network is not limited to CAN communication, and the absolute time of one unit time is different for each of a plurality of Electronic Control Units (ECUs) applied to a vehicle.

[0053] refer to Figure 4 The portion of the original signal (i.e., the instruction signal stored in the buffer unit 140 and not yet delayed by a unit time) that does not maintain its linearity, i.e., the portion where a delay or peak occurs, is obtained by reference to Figure 3 The method corrects and generates a command signal with linearity preservation.

[0054] Figure 5 : is a graph showing a difference between a signal whose linearity is not corrected and a signal whose linearity is corrected by a signal correction method of an SBW system according to an embodiment of the present disclosure.

[0055] Figure 5 A shows a steering angle signal received through a vehicle communication network, indicating that the linearity of the signal corrected by the signal correction method (logic) according to the present embodiment is maintained without delay or peak. Figure 5Figure B shows a signal waveform obtained by differentiating the steering angle signal received via the vehicle communication network, demonstrating that when the signal corrected by the signal correction method (logic) according to this embodiment is differentiated, the linearity of the signal is maintained smoothly and without interference. In a vehicle employing an SBW system, the signal correction device and method of the SBW system according to the embodiments of the present disclosure can correct the signal received by the receiving unit from the transmitting unit via the vehicle communication network, thereby maintaining the linearity of the signal. Therefore, the signal correction device and method can correct portions of the steering angle signal where its linearity is not maintained, i.e., portions where delays or peaks occur, thereby smoothly and stably controlling steering. Although the present disclosure has been disclosed with reference to the embodiments shown in the accompanying drawings, these embodiments are for illustrative purposes only, and those skilled in the art will appreciate that various modifications and other equivalent embodiments can be made from these embodiments. Therefore, the technical scope of the present disclosure should be defined by the appended claims. Furthermore, the embodiments described in this specification can be implemented, for example, by a method or process, an apparatus, a software program, a data stream, or a signal. Although a feature is discussed only in a single context (e.g., discussed only in a method), the discussed feature can be implemented in another type (e.g., an apparatus or program). The apparatus can be implemented in suitable hardware, software, or firmware. The method can be implemented in a device such as a processor, which generally refers to a processing device including a computer, a microprocessor, an integrated circuit, or a programmable logic device. The processor also includes a communication device such as a computer, a cellular phone, a personal digital assistant (PDA), and another device that facilitates information communication between end users.

[0056] Although exemplary embodiments of the present disclosure are disclosed for illustrative purposes, it will be appreciated by those skilled in the art that various modifications, additions, and substitutions are possible without departing from the scope and spirit of the present disclosure as defined in the appended claims. Therefore, the true technical scope of the present disclosure should be defined by the claims.

Claims

1. A signal correction device for a steer-by-wire (SBW) system, comprising: a command signal receiving / transmitting unit for receiving a command signal transmitted from a superior device via a vehicle communication network, and transmitting a command signal obtained by correcting the linearity of the received command signal to a subordinate device via the vehicle communication network; a buffer unit for storing the command signal received by the command signal transmitting / receiving unit as an original signal; and a control unit for correcting the linearity of the original signal by using the original signal stored as the command signal in the buffer unit and a command signal obtained by delaying the command signal stored in the buffer unit by a specified unit time to generate a command signal having corrected linearity; and The counting signal sending / receiving unit is used to receive the counting signal sent by the upper-level device and send the counting signal to the lower-level device.

2. The signal correction device according to claim 1, wherein: The superior device sends a command signal at the superior level through the vehicle communication network according to the command signal transmission system specified by the SBW system; as well as The lower device receives a command signal at a lower level through the vehicle communication network according to the designated command signal transmission system of the SBW system.

3. The signal correction device according to claim 1, wherein: The count signal is separately transmitted / received in synchronization with the command signal received through the vehicle communication network to check the period and linearity of the command signal, and the count signal continuously increases by a specific count value every specified unit time in each period.

4. The signal correction device according to claim 1, wherein: The control unit determines whether linearity of the command signal received through the vehicle communication network is maintained by using a count value of a count signal.

5. The signal correction device according to claim 4, wherein: To determine whether the linearity of the command signal is maintained, the control unit determines whether a delay or a peak occurs by using a count value of the count signal in each cycle.

6. The signal correction device according to claim 1, wherein: The control unit checks a count value of the count signal received in synchronization with the instruction signal in each cycle, and judges that the instruction signal is delayed when the same count value as that of the previous cycle remains even in the current cycle.

7. The signal correction device according to claim 6, wherein: When the command signal has no delay, the control unit generates a command signal to be transmitted to a lower device by using the command signal delayed by one unit time of the corresponding cycle.

8. The signal correction device according to claim 6, wherein: When the instruction signal is delayed, the control unit generates an instruction signal to be transmitted to a lower device by using the original signal of a corresponding period.

9. The signal correction device according to claim 1, wherein: The control unit checks a count value of the count signal received in synchronization with the command signal in each cycle, and determines that a peak occurs in the command signal when a count value doubled from the count value of the previous cycle is detected in the current cycle.

10. The signal correction device according to claim 9, wherein: When a peak does not appear in the command signal, the control unit generates a command signal to be transmitted to a lower device by using the command signal delayed by one unit time in a corresponding cycle.

11. The signal correction device according to claim 9, wherein: When a peak occurs in the command signal, the control unit generates a command signal to be transmitted to a lower-level device by using only a half of an increment of the original signal in a corresponding period.

12. A signal correction method for a steer-by-wire (SBW) system, comprising: The control unit of the signal correction device of the SBW system receives the command signal from the superior device; The control unit stores the instruction signal in a buffer unit as an original signal; determining, by the control unit, whether the linearity of the command signal is maintained; and When the linearity of the command signal is not maintained, the control unit corrects the linearity of the original signal by using the original signal stored as the command signal in the buffer unit and a command signal obtained by delaying the command signal stored in the buffer unit by a specified unit time to generate a command signal with corrected linearity; Wherein, in judging whether the linearity of the instruction signal is maintained, the control unit checks the count value of the count signal received synchronously with the instruction signal in each cycle, and when the same count value as that of the previous cycle is retained even in the current cycle, it is judged that the instruction signal is delayed.

13. The signal correction method according to claim 12, wherein: To correct the linearity of the original signal, when the command signal has no delay, the control unit generates a command signal to be transmitted to a lower device by using the command signal delayed by one unit time in a corresponding cycle.

14. The signal correction method according to claim 12, wherein: In order to correct the linearity of the original signal, when the instruction signal is delayed, the control unit generates an instruction signal to be transmitted to a lower device by using the original signal of a corresponding period.

15. The signal correction method according to claim 12, wherein: In determining whether the linearity of the instruction signal is maintained, the control unit checks the count value of the count signal received synchronously with the instruction signal in each cycle, and when a count value doubled from the count value of the previous cycle is detected in the current cycle, it is determined that a peak appears in the instruction signal.

16. The signal correction method according to claim 12, wherein: To correct the linearity of the original signal, when no peak appears in the command signal, the control unit generates a command signal to be transmitted to a lower device by using the command signal delayed by one unit time in a corresponding cycle.

17. The signal correction method according to claim 12, wherein: To correct the linearity of the original signal, when a peak appears in the command signal, the control unit generates a command signal to be sent to a lower-level device by using only half of an increment of the original signal in a corresponding cycle.

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