Motor control method and device for shift-by-wire system

Abstract

The present application relates to a motor control method and device for a shift-by-wire system. A motor control method for a shift-by-wire system identifies a current position of a switched reluctance (SR) motor as a start position at a time point when a shift request is input, and determines whether the current position of the SR motor is the same as a target position; when the current position and the target position are not the same, a current is applied to rotate the SR motor toward the target position; a time point until actual movement of the SR motor is sensed is counted; when the counted time exceeds a time reference value, lead angle control that increases a rotation speed of the SR motor is performed; a current applied to the SR motor is measured, and the lead angle control is increased or delay angle control that decreases the rotation speed of the SR motor is performed according to the measured current value.

Description

Technical Field

[0001] This invention relates to a motor control method and apparatus for an electronic shift-by-wire (SBW) system, and more specifically, to a motor control method and apparatus that utilizes a switched reluctance (SR) motor as a shift actuator. Background Technology

[0002] According to the cable-shift (SBC) type automatic transmission, which is a type of automatic transmission with a changeable shift range in the prior art, when the shift lever is moved, a stop plate is rotated via the cable, opening a manual valve and opening the P-, R-, N-, and D- channels in the valve body, thereby selecting the desired shift range. However, since the position of the cable must be taken into account in the prior art SBC type, the design is limited by the position of the cable, which may be disadvantageous in terms of assembly and mass production.

[0003] The shift-by-wire type is an alternative to the SBC type in related technologies. The SBW type is a technology that provides ease of operation and increased safety by rotating a stop plate using a motor instead of a cable connected to the shift lever on the driver's seat. The SBW type is configured to detect the operating status of the shift lever via a sensor or switch, and operate the manual valve by rotating the stop plate via a motor. In electric vehicles and DCT systems without a hydraulic circuit, the parking gear simply engages and disengages.

[0004] The stop plate has multiple shift ranges, and the stop roller is statistically stable by an SBW-type stop spring. The motor rotates the stop plate to the appropriate position in response to a driver's request to change the shift range by operating the shift lever, thereby achieving a specific mechanical state of the vehicle system, and thus realizing the state desired by the driver, such as parking or driving.

[0005] When the driver inputs the desired shift range via the gear shift lever, the vehicle control unit needs some time to receive the input, determine the control value of the motor (including the control valves for the rotation direction and rotation angle (displacement of the stop plate), and then, based on the determined control value, actually engage the desired shift range by driving the motor. The timing of this process is typically adjusted based on the motor's responsiveness.

[0006] In particular, because there is a slight time difference between the moment the gear shift lever completes its operation and the moment range information is displayed on the instrument panel or other means after the actual engagement range, the driver can immediately recognize the motor's responsiveness when changing gear ranges. However, inconsistent responsiveness can lead to quality issues, potentially degrading the vehicle's commercial value.

[0007] Conventional brushless DC motors use pulse width modulation (PWM) duty cycle control for speed feedback control, solving the problem of inconsistent response. However, switched reluctance (SR) motors have a cost advantage, but due to the characteristics of SR motors, variable PWM duty cycle control is not possible. Therefore, a technique is needed to ensure consistent response (constant shift time) when using SR motors. Summary of the Invention

[0008] The purpose of this disclosure is to provide a motor control method and apparatus for an electronic shift-by-wire system, which can ensure consistent response (constant shift time) by changing only the software without adding or changing specific hardware in the electronic shift-by-wire system that uses a switched reluctance (SR) motor as the shift actuator.

[0009] To achieve these objectives, according to one aspect of this disclosure, a motor control method for a shift-by-wire (SBW) system, wherein the shift range of an automatic transmission is changed by a switched reluctance (SR) motor, the method comprising: (a) identifying the current position of the SR motor as a starting position at the time point at which a shift request is input, and determining whether the current position of the SR motor is the same as a target position when a request to change the shift range is input; (b) applying a current to cause the SR motor to rotate toward the target position when the current and the target position are not the same; (c) counting a time from the time point at which the current is applied until the time point at which the actual movement of the SR motor is sensed by an operation counter; (d) comparing the counted time with a preset time reference value, and performing a lead angle control that increases the rotational speed of the SR motor when the counted time exceeds the time reference value; and (e) measuring the current applied to the SR motor during the actual shift period in which the SR motor rotates toward the target position, and increasing the lead angle control or performing a delay angle control that decreases the rotational speed of the SR motor based on the measured current value.

[0010] The motor control method for a gear-by-wire system according to an embodiment of the present disclosure may further include (d') a step between steps (d) and (e) whereby step (d) compares the difference between the current position of the SR motor and the starting position after advance angle control with a preset threshold.

[0011] When the difference between the current position of the SR motor and the starting position after the advance angle control is less than a preset threshold, as a comparison result in step (d'), the counter can be initialized, and the method returns to step (c) and repeats the subsequent steps. When executing the subsequent steps, in step (d), advance angle control that increases the rotational speed of the SR motor to a higher speed than that obtained by the previous advance angle control can be performed. When the difference between the current position of the SR motor and the starting position after the advance angle control exceeds a preset threshold, the method can change the process to proceed to step (e).

[0012] In step (e), the measured current value can be compared with a preset reference current value, and advance angle control or delay angle control can be added.

[0013] In step (e), the current error value can be calculated by subtracting the measured current value from the reference current value (current error value = reference current value - measured current value); and the current error value can be compared with a set threshold. When the current error value is larger, the lead angle control can be increased proportionally to the current error value, and when the current error value is smaller, the delay angle control can be executed proportionally to the current error value.

[0014] To achieve these objectives, according to another aspect of the invention, a motor control device for a shift-by-wire system includes: a switched reluctance (SR) motor configured to generate a driving force for rotating a stop plate to a target position; an encoder configured to output a corresponding electrical signal based on the rotation of the SR motor; and a shift-by-wire (SBW) controller configured to set the target position by analyzing signals from a shift lever sensor that senses changes in the position of the shift lever, and configured to control the operation of the SR motor based on signals from the encoder, such that the stop plate can rotate toward the set target position. The SBW controller may include a plurality of processors programmed to apply current to the SR motor when a driver operating the shift lever inputs a request to change the shift range, to count the time from the time the current is applied to the time the actual movement of the SR motor is sensed, to perform advance angle control to increase the rotational speed of the SR motor when the counted time exceeds a preset time reference value, to measure the current applied to the SR motor during the actual shifting period when the SR motor rotates toward the target position, and to increase the advance angle control or perform delay angle control to decrease the rotational speed of the SR motor based on the measured current value.

[0015] The processor may include: a determiner configured to identify the current position of the SR motor at the time of the request to change the shift range as a start position and determine whether the current position of the SR motor is the same as the target position; a current controller configured to apply current to cause the SR motor to rotate toward the target position when the current position and the target position are different from the determination result of the determiner; a counter unit configured to count the time from the time the current controller applies the current until the actual movement of the SR motor is sensed by operating the counter; and a comparator configured to compare the time counted by the counter unit with a preset time reference value, and the current controller may include logic programmed to perform advance angle control that increases the rotational speed of the SR motor when the time counted by the counter unit exceeds the time reference value, and to further increase advance control or perform delay control that decreases the rotational speed of the SR motor based on the current value measured during the actual shifting period when the SR motor rotates toward the target position.

[0016] According to embodiments of this disclosure, in an electronic shift-by-wire system using an SR motor as a shift actuator, consistent response (constant shift time) can be ensured simply by changing the software without adding or changing specific hardware, and thus, commercial value deterioration or safety incidents due to shift delays can be prevented. Attached Figure Description

[0017] The above and other objects, features and advantages of this disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein:

[0018] Figure 1 This is a perspective view showing the range-changing mechanism of a shift-by-wire system applied to an automatic transmission;

[0019] Figure 2 This is a schematic diagram of a motor control device for a gear-shifting system according to an embodiment of the present disclosure;

[0020] Figure 3 This is a reference view used to describe the lead angle control of this disclosure; and

[0021] Figure 4 This is a control flowchart that sequentially shows a series of processes for controlling the motor in an online gear shifting system. Detailed Implementation

[0022] It should be understood that the terms "vehicle" or "vehicular" or other similar terms as used herein include motor vehicles in general, such as passenger cars, including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, vessels, including various boats and ships, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other vehicles powered by alternative fuels (e.g., fuels derived from resources other than petroleum). As described herein, a hybrid vehicle is a vehicle with two or more power sources, such as a gasoline-powered vehicle and an electric-powered vehicle.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that, when used in this specification, the terms “comprises” and / or “comprising” designate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Throughout this specification, unless explicitly stated otherwise, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of the stated elements, but do not exclude any other elements. Furthermore, the terms “unit,” “-er,” “-or,” and “module” described in the specification refer to a unit for performing at least one function and operation, and may be implemented by hardware components or software components and combinations thereof.

[0024] Furthermore, the control logic of this disclosure can be embodied in a non-transitory computer-readable medium containing executable program instructions that are executed by a processor, controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium can also be distributed across a network-coupled computer system, such that the computer-readable medium is stored and executed in a distributed manner, for example, by a telematics server or controller area network (CAN).

[0025] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular forms are intended to include the plural forms.

[0027] The terms “first,” “second,” etc., used in this specification may be used to describe various components, but the components should not be construed as limited to the terms. These terms are used only to distinguish one component from another.

[0028] In the following description with reference to the accompanying drawings, the same parts are given the same reference numerals and are not described repeatedly. However, in describing this disclosure, detailed descriptions of well-known technologies will be omitted so as not to obscure the description of this disclosure with unnecessary detail.

[0029] First, the mechanical structure of the shift range changing mechanism in the shift-by-wire system is outlined.

[0030] Figure 1 This is a perspective view showing the shift range changing mechanism of a shift-by-wire system applied to an automatic transmission.

[0031] Reference Figure 1 The shift range changing mechanism 13 includes a stop plate 15 that operates to determine the position of the valve core 42a of the manual valve 42, and a shift actuator 16 that generates a driving force for rotating the stop plate 15. The shift actuator 16 may be electric and is operated in the same manner as a starter motor (not shown) powered by a battery installed in the vehicle.

[0032] The shift range changing mechanism 13 is connected to the parking mechanism 17 so that they can operate together. The stop plate 15 of the range changing mechanism 13 is rotated by the shift actuator 16, and gradually pushes or pulls the valve core 42a of the manual valve 42 or the parking lever 17c of the parking mechanism 17, thereby determining its position. The stop mechanism consists of the stop plate 15, the rotating shaft 15a, and the stop spring 15b.

[0033] The stop spring 15b can be supported on the valve body 42b of the manual valve 42, and the stop plate 15 can be substantially fan-shaped. The part that serves as the rotation center of the stop plate 15 is mechanically connected to the shift actuator 16 via a rotating shaft 15a. Therefore, the stop plate 15 rotates synchronously with the motor 16a of the shift actuator 16.

[0034] A shift range determining surface 150 (hereinafter referred to as 'position determining surface') consisting of continuous curved waves is formed on the edge of the stop plate 15. The roller 15c of the stop spring 15b is located in a groove at a specific position on the position determining surface 150, thereby maintaining the position determined state (shift range changing state).

[0035] Four grooves can be formed on the positioning surface, corresponding to the range positions P, R, N, and D of the manual valve 42 that operates together with the stop plate 15. Ridges are formed between the grooves and adjacent grooves, for example, between the P-range groove and the R-range groove, or between the R-range groove and the N-range groove. The ridges are the boundaries between adjacent shift ranges.

[0036] The spacing between the grooves defining the shift range and their adjacent ranges is constant; therefore, the spacing between the ridges that form the boundaries between adjacent shift ranges and their adjacent ridges is also constant. However, depending on the circumstances, the spacing between the grooves in the P range and the R range can be larger than the spacing between other grooves. Therefore, all the spacing between the grooves is different.

[0037] The shift actuator 16 is actuated in response to a signal output when the driver operates the shift lever 11, and accordingly, the roller 15c of the stop spring 15b is positioned in any of the four grooves (grooves defining the P-, R-, N-, and D- ranges respectively). Thus, the stop plate 15 is held in a position corresponding to the position of the manual valve 42.

[0038] The shift actuator 16 may include a motor, a switched reluctance (SR) motor 16a (hereinafter referred to as 'motor' for ease of description), a speed reducer 16b for reducing the rotation of the motor, and an encoder 16c for sensing the rotation direction and rotation angle of the motor 16a when the motor 16a rotates and outputting corresponding electrical signals to the SBW controller 14.

[0039] The rotating shaft 15a can be connected to the output shaft (not shown) of the reducer 16b via a spline or the like to rotate together, and the parking mechanism 17 is used to change the output shaft 10 of the automatic transmission 1 to a locked state where it cannot rotate and an unlocked state where it can rotate. The parking mechanism 17 may include a parking gear 17a, a parking locking pawl 17b, a parking lever 17c, etc., formed on the edge of the output shaft 10.

[0040] The basic operation of the shift range changing mechanism 13 constructed in this manner is briefly described below.

[0041] When the driver operates the gear shift lever 11 or the parking switch 12, one of the parking range P, reversing range R, neutral range N, and driving range D of the automatic transmission 1 is selected. Therefore, a signal is output from the gear shift lever sensor 103 or the parking switch 12, and the SBW controller 14 receives the output signal and identifies the selected target range (or target range) P, R, N, or D.

[0042] Based on information about the distance between the current position and the newly identified target position P, R, N, or D, the SBW controller 14 determines the command value of the shift actuator 16 (as a duty cycle value of a control valve including the rotation direction and rotation angle), and rotates the motor 16a forward or backward by a predetermined angle at a timing determined based on the determined command value. Therefore, the rotating shaft 15a and the stop plate 15 rotate by the predetermined angle.

[0043] Timing can be determined by a Hall sensor (not shown), which uses a Hall element installed in the motor and exhibiting the Hall effect. As the motor 16a rotates, the encoder 16c senses the signal change and provides a signal corresponding to the current shift range to the SBW controller 14. The SBW controller 14 performs feedback control on the motor 16a based on the signals from the encoder 16c and the Hall sensor 16d.

[0044] For example, when the shift lever 11 is operated from the neutral range N to the drive range D, the target position signal changes from N to D. The SBW controller 14, which receives this signal, sets the target rotation angle corresponding to the selected target position D, determines the corresponding command value (duty valve), and allows power to be supplied to the motor 16a through the determined command value.

[0045] Furthermore, during electrical transmission, the drive motor 16a is activated, causing its output shaft to rotate. The SBW controller 14 receives a signal corresponding to the rotation angle from the encoder 16c in real time. Based on the signal provided by the encoder 16c, the SBW controller identifies the rotation angle and direction of the motor 16a in real time and performs feedback control on the motor 16a, making the rotation angle of the motor 16a the same as the target rotation angle.

[0046] According to this control, the stop plate 15 rotates counterclockwise. Figure 1 At a predetermined angle, the roller 15c of the stop spring 15d separates from the groove N, slides on an adjacent ridge, and then positions itself into the adjacent groove D. As a result, the valve core 42a of the manual valve 42 slides axially, and the range of the manual valve 42 changes from N to D.

[0047] When the driver manually operates the parking switch 12 and selects the parking range P, the parking lever 17c is pushed forward, and the parking locking pawl 17b is raised by the rotation of the stop plate 15, thereby causing the pawl 17d to engage between the teeth of the parking gear 17a. Therefore, the output shaft 10 of the automatic transmission 1 is locked, and the manual valve 42 stops at position P.

[0048] According to the shift range changing mechanism 13 operating in this manner, the motor's response speed decreases when the load in the motor increases due to external environmental conditions (e.g., extremely low temperatures, aging of related components, etc.). However, unlike servo motors, it is not possible to perform feedback control on SR motors via pulse width modulation (PWM) duty cycle control, so another approach is needed to ensure a consistent response.

[0049] Therefore, this disclosure provides a motor control device for an electronic shift-by-wire system, which can control the speed of the motor by utilizing the effect of the recovery current rise delay when the U-phase power transmission is executed +1 step earlier than the actual mode, based on the motor's responsiveness (response speed) and the current information (actual current information applied to the motor) when the motor is operated in response to a request to change the shift range.

[0050] The following describes a motor control device for a shift-by-wire system applied to a shift-by-wire system according to embodiments of the present disclosure.

[0051] Figure 2 This is a schematic diagram of a motor control device for a gear-shifting system according to an embodiment of the present disclosure.

[0052] Reference Figure 1 The motor control device according to an embodiment of this disclosure includes the aforementioned motor (SR motor) 16a, encoder 16c, and SBW controller 14. The motor 16a is controlled by the SBW controller 14 to rotate the stop plate 15 to a target position, and the SBW controller 14 identifies whether the stop plate 15 has entered the target position based on the signal from the encoder 16c.

[0053] As described above, the SBW controller 14 sets the target position by analyzing the signal output from the shift lever sensor 103 when the shift lever 11 is operated. Furthermore, the SBW controller 14 controls the motor 16a to rotate the stop plate 15 toward the set target position. Specifically, the SBW controller 14 identifies the rotation angle of the motor 16a and controls the motor 16a according to the signal from the encoder 16c, so that the rotation angle becomes the same as the target rotation angle.

[0054] In this disclosure, the SBW controller 14 specifically includes multiple processors programmed to apply current to the motor in response to a request to change the shift range when the shift lever is operated, to determine whether the responsiveness is appropriate based on the time from the time the current is applied to the time when the actual movement of the motor is sensed, and to compensate for the responsiveness by increasing the lead angle control of the motor's rotational speed when the responsiveness deteriorates.

[0055] In particular, the SBW controller 14 includes multiple processors programmed to apply current to the motor when the driver operating the shift lever inputs a request to change the shift range, to time the time from the time the current is applied to the time when the actual movement of the motor is detected, to perform advance angle control to increase the motor rotation speed when the counted time exceeds a preset time reference value, to measure the current applied to the motor during the actual shift period when the motor rotates toward the target position, and to increase the advance angle control or decrease the motor rotation speed based on the measured current value.

[0056] The processor includes: a determiner 140 that identifies the current position of the motor 16a at the time point when a request to change the shift range is input as the starting position, and determines whether the current position of the motor 16a is the same as the target position; and a current controller 142 that applies a current to rotate the motor 16a toward the target position when the current position and the target position are not the same as the determination result of the determiner 140.

[0057] The processor also includes: a counter unit 144, which counts the time from the point when the current controller 142 applies the current until the actual movement of the motor 16a is detected by operating the counter; and a comparator 146, which compares the time counted by the counter unit 144 with a preset time reference value. The time reference value is required through repeated experiments or simulations in the same simulated environment, and may be the time required to provide an optimal response.

[0058] The current controller 142 may include a program (control logic) programmed to determine that the operation of the motor 16a is delayed (response degradation) due to a large actual load, and to compensate for the delay in responsiveness by increasing the rotational speed of the motor 16a through advance angle control when the time counted by the counter unit 144 (the time from the point when the current is applied to the motor 16a to the point when the actual movement of the motor 16a is sensed) exceeds a time reference value.

[0059] The program may include a procedure to appropriately adjust the responsiveness of motor 16a when motor 16a enters an actual shifting period in which motor 16a rotates toward a target position, by increasing the lead angle control based on the current value actually applied to motor 16a and by converting the voltage of the shunt resistor into current through a current meter, or by performing a delay angle control to reduce the rotational speed of motor 16a.

[0060] For reference, such as Figure 3As shown in the reference view, advance angle control refers to the control that increases the speed of motor 16a by utilizing the effect of the recovery current rise delay when the U-phase power transmission is executed +1 task earlier than the actual mode, while delay angle control refers to the control that decreases the speed of motor 16a by executing the U-phase power transmission -1 task later than the actual mode.

[0061] Reference Figure 4 The control flowchart describes in more detail the motor control processing performed by the motor control device for an electronic shift-by-wire system according to the embodiments of the present disclosure described above. For ease of description, refer to... Figure 1 and Figure 2 The reference numerals of the components shown are used to describe them.

[0062] Figure 4 It is a control flowchart that sequentially shows a series of motor control processes performed by the motor control device used in the electronic shift-by-wire system.

[0063] Reference Figure 4 The motor control method for the electronic shift-by-wire system begins at step S100. In step S100, the current position of motor 16a is identified as the starting position at the time of the shift request, and when a request to change the shift range is input, it is determined whether the current position of motor 16a is the same as the target position. If the current position of motor 16a is the same as the target position in step S100, then in response to the request to change the shift range, it is determined that the shift range has been changed, and the process ends without further action.

[0064] However, if the current position and the target position are different from the results determined in step S100, step S200 is executed, which applies current to the motor 16a to rotate the motor 16a toward the target position. In step S200, the target rotation angle is determined based on the distance information from the current position to the selected target position (target shift range), and power transmission is allowed until the rotation angle of the motor 16a reaches the target rotation angle.

[0065] When a current is applied in step S200 to rotate the motor 16a to the target position, step S300 is executed, which involves counting the time from the time the current is applied until the actual movement of the motor 16a is sensed using an operation counter. In step S300, the time point at which a change in the output of the encoder 16c is sensed after the current is applied can be identified as the time point at which the actual movement of the motor 16a is sensed.

[0066] The counted time in step S300 is provided as a comparison value for comparison with a time reference value set in the next step S400. In step S400, when the counted time in step S300 exceeds the time reference value, it is determined that the rotational speed of the motor has decreased at the initial set speed, and a predetermined control is implemented to compensate for the decreased reaction speed by increasing the rotational speed of the motor 16a.

[0067] The predetermined control can be a lead angle control that increases the rotational speed of motor 16a. As described above, lead angle control refers to the control that increases the speed of motor 16a by utilizing the effect of the recovery current rise delay when the U-phase power transmission is executed +1 steps earlier than the actual mode.

[0068] However, when the counted time in step S300 is less than the time reference value, it is determined that the rotational speed of motor 16a is an appropriate speed, and the process can proceed to the next step S500 without going through the predetermined control for increasing the rotational speed of motor 16a, i.e., the lead angle control step.

[0069] After step S400, step S500 is executed, comparing the difference between the current position and the starting position of motor 16a with a preset threshold. If the difference between the current position and the starting position after advance angle control is less than the preset threshold in step S500, it indicates that even though advance angle control has been performed, motor 16a has not moved sufficiently to the target position. Therefore, the counter is initialized and the process returns to step S300.

[0070] Specifically, when the difference between the current position of motor 16a and the starting position after advance angle control is less than a preset threshold, as determined by the comparison in step S500, the counter is initialized, and the process returns to step S300, repeating the subsequent processing. During the repeated processing, advance angle control is performed to increase the rotational speed of motor 16a to a higher speed than the previous advance angle control (e.g., U-phase power transmission is performed +2 tasks earlier than in the actual mode).

[0071] However, when the difference between the current position of motor 16a and the starting position after advance angle control exceeds a preset threshold, as determined by the comparison in step S500, it is determined that motor 16a has entered the actual shifting period of motor rotation toward the target position, and the process proceeds to step S600, which will be described below.

[0072] In step S600, the current applied to motor 16a during the actual shifting period when motor 16a rotates toward the target position is measured, and delay angle control that increases the lead angle or decreases the rotational speed of motor 16a is executed based on the measured current value. In step S600, the lead angle control can be increased or the delay angle control that decreases the rotational speed can be executed by comparing the measured current value with a preset reference current value.

[0073] Step S600 is described in more detail.

[0074] When the process enters step S600, the current error value S610 is calculated first. The current error value can be obtained by subtracting the current value of motor 16a measured during the actual gear shift from the reference current value (the measured current value), that is, it can be calculated by the simple equation "current error value = reference current value - measured current value".

[0075] The current value of motor 16a, that is, the reference current value used as the basis for calculating the current error value, can be set to different values ​​according to the battery voltage. This is to prevent the current rise caused by the battery voltage difference from being incorrectly identified as an increase in load on motor 16a.

[0076] When the current error value is derived through step S610, it is determined whether the actual rotation angle of motor 16a (calculated by encoder output) and the target rotation angle have reached the stop control period of motor 16a (determining whether the rotation position of motor 16a is close to the target position) (S620). When it is determined that the stop control period of motor 16a has been reached, the advance angle control of motor 16a is stopped, and the stop control of motor 16a (2-phase power transmission) is executed so that motor 16a can stop at the target position (S622).

[0077] However, when motor 16a has not reached the stop control period, the current error value calculated in step S610 is compared with a predetermined set threshold. When the current error value is larger, a lead angle control proportional to the current error value is executed, and when the current error value is smaller, a delay angle control proportional to the current error value is executed.

[0078] For example, such as Figure 4 As shown, the current error value is compared with a set threshold 1, which serves as the maximum threshold. When the current error value is greater than the set threshold 1 (current error value > set threshold 1), the lead angle control increases by +2. Furthermore, when the current error value is less than the set threshold 1 (current error value < set threshold 1), the current error value is again compared with a set threshold 2, which is less than the set threshold 1.

[0079] When the current error value is greater than the set threshold 2 (set threshold 1 > current error value), the lead angle control only adds +1 task as a comparison result. When the current error value is less than the set threshold 2 (current error value < set threshold 2), the current error value is compared again with the set threshold 3, which is less than the set threshold 2. When the current error value is less than the set threshold 3, the lead angle control reduces -2 tasks (-2 task delay angle control).

[0080] However, when the current error value is greater than the set threshold 3, the current error value is compared with the set threshold 4, which is greater than the set threshold 3 and less than the set threshold 2. When the current error value is less than the set threshold 4 (set threshold 3 < current error value < set threshold 4), the lead angle control only reduces the number of tasks by -1 (-1 task delay angle control), and when the current error value is greater than the set threshold 4 (set threshold 4 < current error value < set threshold 2), neither the lead angle nor the delay angle control needs to be executed.

[0081] According to the embodiments of the present disclosure described above, in an electronic shift-by-wire system using an SR motor as a shift actuator, consistent response (constant shift time) can be ensured simply by changing the software without adding or changing specific hardware, and thus, commercial value deterioration or safety incidents due to shift delays can be prevented.

[0082] The above detailed description describes only specific embodiments. This disclosure should not be construed as limiting itself to the specific embodiments described above, but should be construed as including all changes, equivalents, and substitutions within the spirit of this disclosure as defined in the claims.

Claims

1. A motor control method for a drive-by-wire shifting system, wherein, The shift range of the automatic transmission is changed by a switched reluctance motor, and the motor control method includes: a) Identify the current position of the switched reluctance motor as the starting position at the time the shift request is input, and determine whether the current position of the switched reluctance motor is the same as the target position when a request to change the shift range is input. b) When the current position and the target position are not the same, apply a current to make the switched reluctance motor rotate toward the target position; c is the step of counting the time from the point when the current is applied until the actual movement of the switched reluctance motor is sensed by using an operation counter. d compares the counted time with a preset time reference value, and performs a lead angle control step to increase the rotational speed of the switched reluctance motor when the counted time exceeds the time reference value; and e measures the current applied to the switched reluctance motor during the actual shifting period of the switched reluctance motor as it rotates toward the target position, and increases the lead angle control or performs a delay angle control to reduce the rotational speed of the switched reluctance motor based on the measured current value.

2. The motor control method according to claim 1 further includes: d' is the step between steps d and e, where the difference between the current position and the starting position of the switched reluctance motor is compared with a preset threshold after advance angle control is performed in step d.

3. The motor control method according to claim 2, wherein, When the difference between the current position of the switched reluctance motor and the starting position after advance angle control is less than the preset threshold, as a comparison result in step d', the counter is initialized, and the method returns to step c and repeats the subsequent steps. When the subsequent steps are executed, advance angle control is performed in step d to increase the rotational speed of the switched reluctance motor to a higher speed than that obtained by the previous advance angle control.

4. The motor control method according to claim 2, wherein, When the difference between the current position of the switched reluctance motor and the starting position after advance angle control, as a comparison result in step d', exceeds the preset threshold, the method changes the process to proceed to step e.

5. The motor control method according to claim 1, wherein, In step e, the measured current value is compared with the preset reference current value, and lead angle control is added or delay angle control is executed.

6. The motor control method according to claim 5, wherein, The current error value is calculated by subtracting the measured current value from the reference current value. The current error value is compared with a set threshold. When the current error value is larger, the lead angle control is increased proportionally to the current error value. When the current error value is smaller, the delay angle control is executed proportionally to the current error value.

7. A motor control device for a drive-by-wire shifting system, comprising: A switched reluctance motor is configured to generate a driving force for rotating the stop plate to a target position; The encoder is configured to output a corresponding electrical signal based on the rotation of the switched reluctance motor; as well as The shift-by-wire controller is configured to set a target position by analyzing signals from a shift lever sensor that senses changes in the position of the shift lever, and is configured to control the operation of the switched reluctance motor based on signals from the encoder, such that the stop plate can rotate toward the set target position. The shift-by-wire controller includes multiple processors programmed to apply current to the switched reluctance motor when the driver operating the shift lever requests a change in the shift range, to count the time from the time the current is applied to the time the actual movement of the switched reluctance motor is sensed, and to perform advance angle control to increase the rotational speed of the switched reluctance motor when the counted time exceeds a preset time reference value. The controller also measures the current applied to the switched reluctance motor during the actual shifting period when the switched reluctance motor rotates toward the target position, and, based on the measured current value, either increases the advance angle control or performs delay angle control to decrease the rotational speed of the switched reluctance motor.

8. The motor control device according to claim 7, wherein, The processor includes: The determiner is configured to identify the current position of the switched reluctance motor at the time when a request to change the shift range is input as a start position, and to determine whether the current position of the switched reluctance motor is the same as the target position. A current controller is configured to apply current to cause the switched reluctance motor to rotate toward the target position when the current position and the target position are not the same as the determination result of the determiner. The counter unit is configured to start from the time point when the current controller applies current until the time point when the actual movement of the switched reluctance motor is sensed by operating the counter; and A comparator is configured to compare the time counted by the counter unit with a preset time reference value, and When the time counted by the counter unit exceeds the time reference value, the current controller performs advance angle control to increase the rotational speed of the switched reluctance motor, and further increases advance control or performs delay control to decrease the rotational speed of the switched reluctance motor based on the current value measured during the actual shifting period when the switched reluctance motor rotates toward the target position.

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