Steering control device and steering control method

Abstract

The present application relates to a kind of steering control device and steering control method, the steering control device is used to control first motor and second motor, corresponding to the rotation of first steering wheel, first motor generates steering feedback torque, second motor generates rack drive torque for moving rack (Rack), comprising: calculation part, based on rack thrust information and preset second motor performance information, calculate the rack speed information related to the rack speed allowed in the case of driving rack using second motor is allowed, and based on the instruction rack speed information generated by driving rack at the speed corresponding to the rotation of steering wheel and the rack speed information allowed, calculate the steering response lag prevention torque information for preventing steering response lag (Catch-up) on steering wheel;Control part, based on steering response lag prevention torque information, to first motor executes steering response lag prevention control.

Description

Technical Field

[0001] This invention relates to a steering control device and a steering control method, and more specifically, to a steering control device and a steering control method capable of correcting the steering feedback torque based on the output of a motor. Background Technology

[0002] In a vehicle's steering system, due to the limited capacity of the steering mechanism, a steering response lag (catch-up) phenomenon may occur, where the driver cannot feel the reaction force or cannot steer at the desired speed.

[0003] Relatedly, unlike electric power steering (EPS) systems where the upper and lower ends are physically connected, steer-by-wire (SBW) systems, due to the physical separation of the upper and lower ends, may experience a problem where the steering response lag is difficult to perceive at the upper end.

[0004] Therefore, it is also necessary to develop a technology in the SBW system that can quickly identify and prevent steering response lag in advance. Summary of the Invention

[0005] The problem the invention aims to solve The purpose of this invention is to provide a steering control device and a steering control method that can prevent steering response lag caused by motor capacity limitations.

[0006] In addition, the present invention aims to provide a steering control device and a steering control method that can predict the possibility of steering response lag based on command information and motor information generated by the rotation of the steering wheel.

[0007] means for solving problems On one hand, this embodiment can provide a steering control device for controlling a first motor and a second motor, corresponding to the rotation of a steering wheel. The first motor generates steering feedback torque, and the second motor generates rack drive torque for moving a rack. The steering control device includes: a calculation unit that calculates allowable rack speed information based on rack thrust information and preset second motor performance information, the allowable rack speed information being related to the rack speed allowed when the rack is driven using the second motor; and calculates steering response hysteresis prevention torque information for preventing steering response hysteresis on the steering wheel based on commanded rack speed information and the allowable rack speed information, the commanded rack speed information being generated for driving the rack at a speed corresponding to the rotation of the steering wheel; and a control unit that performs steering response hysteresis prevention control on the first motor based on the steering response hysteresis prevention torque information.

[0008] On the other hand, this embodiment can provide a steering control method for controlling a first motor and a second motor corresponding to the rotation of a steering wheel. The first motor generates steering feedback torque, and the second motor generates rack drive torque for moving a rack. The steering control method includes: a step of calculating allowable rack speed information, which calculates allowable rack speed information based on rack thrust information and preset second motor performance information, wherein the allowable rack speed information is related to the rack speed allowed when the rack is driven by the second motor; a step of calculating steering response hysteresis prevention torque information, which calculates steering response hysteresis prevention torque information for preventing steering response hysteresis (catch-up) on the steering wheel based on commanded rack speed information and allowable rack speed information, wherein the commanded rack speed information is generated to drive the rack at a speed corresponding to the rotation of the steering wheel; and a step of steering response hysteresis prevention control, which performs steering response hysteresis prevention control on the first motor based on the steering response hysteresis prevention torque information.

[0009] Invention Effects According to the present invention, a steering control device and a steering control method are provided that can prevent steering response lag caused by motor capacity limitations.

[0010] In addition, according to the present invention, a steering control device and a steering control method can be provided that can predict the possibility of steering response lag based on command information and motor information generated by the rotation of the steering wheel. Attached Figure Description

[0011] Figure 1 This is a block diagram related to the steering control device of the present invention.

[0012] Figure 2 This is a diagram illustrating an exemplary configuration of a steering device for a vehicle according to one embodiment.

[0013] Figure 3 This is an exemplary diagram illustrating the configuration of a steering system in a vehicle according to an embodiment that enables the steering control device to operate.

[0014] Figure 4 This is a diagram illustrating, by way of example, the steering response lag in the steering system of a vehicle according to one embodiment.

[0015] Figure 5 This is a diagram illustrating, by way of example, the configuration of a steering response hysteresis prevention control in a vehicle's steering system according to an embodiment.

[0016] Figure 6 This is an exemplary diagram illustrating the configuration of a steering control device utilizing second motor performance information according to one embodiment.

[0017] Figure 7 This is an exemplary diagram illustrating the configuration of a steering control device utilizing a lookup table according to one embodiment.

[0018] Figure 8 This is a sequence diagram related to the steering control method of the present invention.

[0019] Figure 9 This is an exemplary diagram illustrating the sequence of processes for calculating the final torque in a steering control method according to one embodiment.

[0020] Figure 10 This is a sequence diagram used to illustrate a steering control method according to yet another embodiment. Detailed Implementation

[0021] Hereinafter, this embodiment will be described in detail with reference to the exemplary accompanying drawings. When assigning reference numerals to the constituent elements in the various drawings, the same reference numerals will be used as much as possible for the same constituent element, even if it is shown in different drawings. In addition, in the description related to this embodiment, detailed descriptions of related known structures or functions may be omitted if it is determined that such detailed descriptions may obscure the main idea of ​​the present invention. When using terms such as "comprising," "possessing," or "component" as mentioned in this specification, other parts may be added as long as "only~" is not used. When a constituent element is expressed in a singular form, it may include a plural form unless there is a particularly clear statement.

[0022] Furthermore, in the descriptions relating to the constituent elements of this embodiment, terms such as "first," "second," "A," "B," "(a)," and "(b)" may be used. These terms are used only to distinguish their constituent elements from other constituent elements, and the nature, order, sequence, or number of the corresponding constituent elements are not limited by the terms.

[0023] In descriptions relating to the positional relationships of constituent elements, when two or more constituent elements are described as "connected," "combined," or "linked," it should be understood that the two or more constituent elements can be directly "connected," "combined," or "linked." However, the two or more constituent elements can also be "connected," "combined," or "linked" in a manner that also "intersperses" other constituent elements. Among these, the other constituent elements can also be included in one or more of the two or more constituent elements that are "connected," "combined," or "linked" to each other.

[0024] In descriptions relating to temporal relationships of constituent elements, methods of action, or manufacturing methods, for example, when describing temporal or procedural relationships such as “after,” “following,” “after,” or “before,” discontinuous situations may also be included, provided that “directly” or “directly” is not used.

[0025] On the other hand, when referring to numerical values ​​or their corresponding information (e.g., level) related to a constituent element, even without additional explicit description, the numerical value or its corresponding information can be interpreted as including the range of errors that may occur due to various factors (e.g., factors in the process, internal or external shocks, noise, etc.).

[0026] Figure 1 This is a block diagram related to the steering control device of the present invention.

[0027] refer to Figure 1 The steering control device 100 according to the present invention may include a calculation unit 110 and a control unit 120. Furthermore, the calculation unit 110 and the control unit 120 may be connected to each other.

[0028] As an example, the steering control device 100 may be a steering control device for controlling a first motor and a second motor. Corresponding to the rotation of the steering wheel, the first motor generates steering feedback torque, and the second motor generates rack drive torque for driving the rack. It may include: a calculation unit 110, which calculates allowable rack speed information based on rack thrust information and preset second motor performance information, the allowable rack speed information being related to the rack speed allowed when the rack is driven using the second motor, and calculates steering response hysteresis prevention torque information for preventing steering response hysteresis on the steering wheel based on commanded rack speed information and allowable rack speed information, the commanded rack speed information being generated to drive the rack at a speed corresponding to the rotation of the steering wheel; and a control unit 120, which performs steering response hysteresis prevention control on the first motor based on the steering response hysteresis prevention torque information.

[0029] The calculation unit 110 can calculate: permissible rack speed information related to the rack speed allowed when the rack is driven by the second motor; and steering response lag prevention torque information for preventing steering response lag (catch-up) on the steering wheel.

[0030] As an example, the calculation unit 110 can calculate the allowable rack speed information based on the rack thrust information and the second motor performance information.

[0031] Specifically, the calculation unit 110 can calculate the corresponding motor torque information and corresponding motor speed information corresponding to the rack thrust information based on the second motor performance information, and can calculate the allowable rack speed information based on the corresponding motor torque information and corresponding motor speed information.

[0032] Here, the second motor performance information may include rack thrust-motor torque information, motor torque-motor speed information, and rack speed-damping torque information. Additionally, the rack thrust-motor torque information may include first look-up table information, the motor torque-motor speed information may include second look-up table information, and the rack speed-damping torque information may include third look-up table information.

[0033] As an example, the first lookup table information may include information related to the first lookup table, in which the motor torque value corresponding to each rack thrust value is stored using each rack thrust value as an index.

[0034] Specifically, when using the information in the first lookup table, a specific rack thrust value can be used as an index to calculate the motor torque value corresponding to that specific rack thrust value; or, a specific motor torque value can be used as an index to calculate the rack thrust value corresponding to that specific motor torque value.

[0035] As another example, the second lookup table information may include information related to the second lookup table, which stores motor speed values ​​corresponding to each motor torque value, indexed by each motor torque value.

[0036] Specifically, when using the information from the second lookup table, a specific motor torque value can be used as an index to calculate the motor speed value corresponding to that specific motor torque value, or a specific motor speed value can be used as an index to calculate the motor torque value corresponding to that specific motor speed value.

[0037] As another example, the third lookup table information may include information related to the third lookup table, which stores the damping torque value corresponding to each rack speed value, indexed by the rack speed value.

[0038] Specifically, by using the information from the third lookup table, a specific rack speed value and a specific rack speed difference can be used as an index to extract the corresponding damping torque value, and the damping torque information can be calculated based on the extracted damping torque value.

[0039] Regarding this second motor performance information and related information included therein, as follows: Figure 6 and Figure 7 A more detailed explanation follows.

[0040] The calculation unit 110 can calculate the corresponding motor torque information based on the rack thrust information and the rack thrust-motor torque information. For example, the calculation unit 110 can calculate the corresponding motor torque information based on the first lookup table information included in the rack thrust information and the rack thrust-motor torque information.

[0041] Alternatively, if the rack thrust-motor torque information is information that can output a motor torque value in the form of a graph related to the relationship between rack thrust and motor torque, or in the form of a formula for outputting a motor torque value based on the input rack thrust value, then the motor torque value corresponding to the rack thrust value of the rack thrust information is calculated from these graphs or formulas, and the calculated motor torque value is used as the corresponding motor torque information.

[0042] The calculation unit 110 can calculate the corresponding motor speed information based on the corresponding motor torque information and the motor torque-motor speed information. For example, the calculation unit 110 can calculate the corresponding motor speed information based on the second lookup table information included in the corresponding motor torque information and the motor torque-motor speed information.

[0043] Alternatively, if the motor torque-motor speed information is information that outputs a motor speed value in the form of a graph or formula that relates the motor torque to the motor speed, the motor torque value corresponding to the rack thrust value of the rack thrust information can be calculated from these graphs or formulas, and the calculated motor torque value can be used as the corresponding motor torque information.

[0044] The calculation unit 110 can calculate the allowable rack speed information based on the corresponding motor speed information. Specifically, it can calculate the rack speed based on the relationship between the second motor speed and the rack speed, in a manner that allows for the calculation of the rack speed corresponding to the second motor when it is driven at the corresponding motor speed.

[0045] For example, the calculation unit 110 can calculate the allowable rack speed information by multiplying the corresponding motor speed information by a preset gear constant. Alternatively, it can use a lookup table storing rack speed values ​​corresponding to each motor speed value to calculate the allowable rack speed information.

[0046] The calculation methods for the gear constant and those using lookup tables can be used, either by selecting one based on preset selection criteria and calculating it, or by calculating both methods and then calculating the allowable rack speed based on the two results. In the case of two calculation results, the average of the two results can be used to calculate the allowable rack speed. Alternatively, the smaller value of the two results can be used to calculate the allowable rack speed.

[0047] For example, the selection criteria can be arbitrarily chosen by the user. Alternatively, the selection criteria can be as follows: if the vehicle's action (movement) state determines that it is necessary to consider additional information besides the corresponding motor speed information, a method using the corresponding lookup table can be selected; if it is determined that it is not necessary to consider additional information, a method using the gear constant can be selected.

[0048] On the other hand, the calculation unit 110 can calculate the preset critical rack speed information as the allowable rack speed information when the rack thrust information is below the preset critical thrust information.

[0049] Typically, in a motor torque-motor speed graph, the relationship between motor torque and motor speed can be defined as a relationship that is closer to an inverse relationship as motor speed decreases, so that motor torque can be increased in a general sense.

[0050] However, exceptions may include: a range in which the motor speed has a constant value in all cases where the motor torque is below a constant value; and a range in which the motor torque has a constant value in all cases where the motor speed is below a constant value.

[0051] Here, for critical thrust information, in the motor torque-motor speed graph, within the range where the motor speed value does not increase below a constant value regardless of the increase in the motor torque value, the motor torque value corresponding to the motor speed value and the rack thrust value corresponding to the motor torque value can be set to the rack thrust value at the maximum position.

[0052] Furthermore, in this case, for the critical rack speed information, the motor speed value corresponding to the critical thrust information can be obtained from the motor torque-motor speed graph, and the rack speed value corresponding to the motor speed value can be set based on the relationship between the motor speed and the rack speed.

[0053] In summary, when the critical thrust information and critical rack speed information are preset, and the rack thrust is above the critical thrust, the critical rack speed information can be calculated as the allowable rack speed information without additional complex calculations. Therefore, the overall calculation speed of the allowable rack speed information can be improved.

[0054] As another example, the calculation unit 110 can calculate steering response lag prevention torque information based on the command rack speed information and the allowable rack speed information. Here, steering response lag prevention torque refers to the motor torque generated on the first motor in order to prevent steering response lag when the second motor and rack are driven based on a command that exceeds the capacity limit of the second motor.

[0055] Furthermore, for this steering response lag prevention torque information, the damping torque information can be calculated based on the command rack speed information and the allowable rack speed information, and can be calculated in the following way, that is, by adding the steering feedback torque and damping torque information calculated according to the existing logic without considering whether the steering response lag is present.

[0056] First, the calculation unit 110 can calculate the damping torque information based on the command rack speed information, the allowed rack speed information, and the rack speed-damping torque information. Here, the damping torque information may include third lookup table information, in which the damping torque value corresponding to each rack speed value is stored, indexed by the rack speed value.

[0057] Typically, steering response lag can occur when the second motor and rack are driven based on commands exceeding the capacity limits of the second motor. Taking this into account, if the commanded rack speed information exceeds the permissible rack speed information, it can be determined that there is a possibility of steering response lag when the second motor and rack are driven based on the commanded rack speed information.

[0058] Relatedly, the calculation unit 110 can calculate rack speed difference information related to the difference between the commanded rack speed information and the permissible rack speed information. In this case, the rack speed difference information can be calculated using the formula "rack speed difference information = commanded rack speed – permissible rack speed".

[0059] Specifically, when the rack speed difference information is ≥ 0, there is a possibility of steering response lag when the second motor and rack are driven based on the commanded rack speed information. Therefore, it can be configured to perform steering response lag prevention control in the control unit 120 afterwards. Conversely, when the rack speed difference information is < 0, the possibility of steering response lag is smaller. Therefore, it can be configured not to perform steering response lag prevention control in the control unit 120 afterwards.

[0060] On the other hand, even if the difference between the commanded rack speed and the permissible rack speed is the same, the magnitude of the damping torque required to prevent steering response lag and the magnitude of the steering response lag prevention torque can vary depending on the magnitude of the motor torque occurring in the second motor.

[0061] With this in mind, the rack speed-damping torque information and the third lookup table information included in the rack speed-damping torque information can be configured to calculate the damping torque information by fully considering both the rack speed information and the rack speed difference information.

[0062] For example, if the allowable rack speed information is 0.5 m / s and the commanded rack speed information is 0.7 m / s, the rack speed difference information can be calculated as 0.2 m / s. In this case, the third lookup table information can be set to calculate the damping torque information as 1.1 Nm.

[0063] Furthermore, when the allowable rack speed information is 2.0 m / s and the commanded rack speed information is 2.2 m / s, the rack speed difference information can be calculated as 0.2 m / s. In this case, the third lookup table information can be set to calculate the set damping torque information as 2.1 Nm.

[0064] Thus, in the process of calculating the third lookup table information, even when the rack speed difference information is calculated to be the same 0.2 m / s, if the allowable rack speed information and the command rack speed information are relatively large, the damping torque information can be set to be calculated to a relatively large value; and if the allowable rack speed information and the command rack speed information are relatively small, the damping torque information can be set to be calculated to a relatively small value.

[0065] In summary, the calculation unit 110 can calculate the damping torque information by taking into account all allowable rack speed information and rack speed difference information during the process of setting rack speed-damping torque information and third lookup table information.

[0066] The calculation unit 110 can calculate steering response hysteresis prevention torque information based on steering feedback torque and damping torque information.

[0067] Here, steering feedback torque refers to the torque generated on the first motor in order to transmit steering feel corresponding to the rotation of the steering wheel. The steering feedback torque may include both steering assist torque and steering reaction torque.

[0068] Additionally, the steering feedback torque may include a torque configured to be generated according to existing logic. Here, existing logic may include: logic related to the calculation and control of steering feedback torque that does not include a portion taking into account whether or not steering response lag occurs.

[0069] Specifically, the calculation unit 110 can calculate steering response hysteresis prevention torque information based on the steering feedback torque calculated according to existing logic and the damping torque information calculated according to the present invention. For example, the steering response hysteresis prevention torque can be calculated by adding the magnitude of the steering feedback torque and the magnitude of the damping torque.

[0070] In this situation, steering response lag typically occurs due to the limited capacity of the second motor, resulting in smaller motor torque, rack speed, and other parameters. Therefore, the steering response lag prevention torque is calculated to be greater than the steering feedback torque, thereby providing a relatively heavier steering feel. That is, the damping torque added to the steering feedback torque can be calculated as a torque value in the same direction as the steering feedback torque.

[0071] On the other hand, the calculation unit 110 can set an upper dead zone limit and a lower dead zone limit based on the allowable rack speed information, thereby calculating dead zone interval information. In this case, the dead zone interval set based on the dead zone interval information can be set to a range below the upper dead zone limit and above the lower dead zone limit.

[0072] Depending on the circumstances, there may be situations where vehicle steering control is continuously performed within a range close to the permissible rack speed caused by the limitation of the second motor capacity.

[0073] In this case, if the calculation of steering response lag prevention torque and the determination of whether or not to control steering response lag are performed only based on specific values ​​of the performance information of the second motor, the frequent execution of such calculations and controls may have an adverse effect on the efficiency of steering control.

[0074] To improve this problem, dead zone information is calculated based on the allowable rack speed information, and the calculation of steering response lag prevention torque and the determination of whether or not to implement steering response lag prevention control are performed based on the dead zone information. This improves the efficiency of steering response lag prevention control and enhances the stability of steering control.

[0075] The control unit 120 can perform steering response hysteresis prevention control on the first motor based on steering response hysteresis prevention torque information. In this case, the steering response hysteresis prevention control may include controlling the first motor to generate steering response hysteresis prevention torque based on the steering response hysteresis prevention torque information.

[0076] Furthermore, the control unit 120 can be configured to execute the steering response lag prevention control when the steering response lag prevention control meets preset conditions.

[0077] As an example, the control unit 120 can perform steering response lag prevention control when the rack speed difference information is above a preset reference speed difference. Here, the reference speed difference can be set to a constant specific value, or it can be set based on the allowable rack speed information.

[0078] For example, the reference speed difference can be set to a specific value of 0.1 m / s. In this case, assuming the allowable rack speed information is 1.0 m / s, then when the commanded rack speed information is 1.1 m / s or higher, the rack speed difference information will be greater than or equal to the reference speed difference of 0.1 m / s, thus steering response lag prevention control can be implemented. Assuming the allowable rack speed information is 2.0 m / s, then when the commanded rack speed information is 2.1 m / s or higher, the rack speed difference information will be greater than or equal to the reference speed difference of 0.1 m / s, thus steering response lag prevention control can be implemented.

[0079] As another example, the reference speed difference can be set to a ratio of 10% of the allowable rack speed information. In this case, the reference speed difference is 0.1 m / s when the allowable rack speed is 1.0 m / s, and 0.2 m / s when the allowable rack speed is 2.0 m / s. Based on this, it is used as a reference and compared with the rack speed difference information to determine whether to perform steering response lag prevention control.

[0080] Comparing the two methods mentioned above related to the setting of the reference speed difference, the calculation process of the method with a specific value becomes simpler, thus enabling faster execution of the determination of whether to perform steering response lag prevention control, which has advantages in terms of control speed. When the ratio value is set based on the allowable rack speed information, the allowable rack speed information can be matched to calculate a more accurate reference speed difference, thus enabling more accurate execution of the determination of whether to perform steering response lag prevention control, which has advantages in terms of control accuracy and precision.

[0081] On the other hand, the control unit 120 can perform steering response lag prevention control when the command rack speed information exceeds the dead band range of the dead band range information. For example, when the dead band range is set to be below the upper dead band limit and above the lower dead band limit, the control unit 120 can perform steering response lag prevention control when the command rack speed information exceeds the upper dead band limit or is less than the lower dead band limit. That is, a configuration for performing dead band processing can be added to the determination of whether to start / end the steering response lag prevention control.

[0082] For example, if the rack speed information is allowed to be calculated as 1.0 m / s, the size of the dead zone is set to 0.2 m / s, the upper limit of the dead zone is set to 1.2 m / s, and the lower limit of the dead zone is set to 1.0 m / s, so that the dead zone information can be calculated.

[0083] In this case, if the allowable rack speed information is 1.0 m / s and the commanded rack speed information is 1.1 m / s, it is determined that it is within the dead zone interval information, so steering response lag prevention control can be omitted.

[0084] In this case, if the allowable rack speed information is 1.0 m / s and the commanded rack speed information is 1.3 m / s, it is determined that the range does not exceed the dead zone range information, and thus steering response lag prevention control can be executed.

[0085] In addition, depending on the situation, if the steering response lag prevention control is started when the command rack speed information is determined to exceed the upper limit of the dead zone, the steering response lag prevention control will continue to be executed when the command rack speed information is above the lower limit of the dead zone, even if the command rack speed information subsequently decreases to below the upper limit of the dead zone. The steering response lag prevention control will only end when the command rack speed information decreases to below the lower limit of the dead zone.

[0086] This dead-zone handling prevents frequent switching between the start and end of steering response hysteresis prevention control, even when the commanded rack speed information continuously approaches, exceeds, or falls below the allowed rack speed information. Consequently, the inefficiency caused by the start / end of steering response hysteresis prevention control itself is minimized, thereby improving the stability of steering control.

[0087] Figure 2 This is a diagram illustrating an exemplary configuration of a steering device for a vehicle according to one embodiment.

[0088] Reference Figure 2 According to one embodiment, the steering device 200 may include at least one of a steering control device 100, a steering wheel 210, a first motor 220, a rack 250, and a second motor 260. Here, the steering wheel 210, the first motor 220, the rack 250, and the second motor 260 may be physically separate from each other.

[0089] Alternatively, the steering device 200 according to one embodiment may be a steer-by-wire device, which includes: a first actuator connected to a steering wheel 210 and generating steering feedback torque using a first motor 220; and a second actuator mechanically separated from the first actuator and connected to a rack 250, generating rack drive torque using a second motor 260.

[0090] In this case, the first drive may include not only the steering wheel 210 and the first motor 220, but also any configuration required for the operation of the upper end of the steering device 200, such as the configuration for enabling the steering wheel 210 and the first motor 220 to work or calculate and transmit information generated by such work, and the configuration for calculating, generating and transmitting steering torque and steering feedback torque.

[0091] In addition, the second drive may include not only the rack 250 and the second motor 260, but also any configuration required for the operation of the lower end of the steering device 200, such as the configuration for enabling the rack 250 and the second motor 260 to work or calculate and transmit information generated by such work, and the configuration for calculating, generating and transmitting rack drive torque.

[0092] The steering wheel 210 is a component included in the upper part of the steering device. Any component that generates changes in steering angle and steering torque in the steering device through the rotation of the steering wheel 210 can be included.

[0093] The first motor 220 is a configuration included in the upper end of the steering device, and is a configuration that generates steering feedback torque in response to the rotation of the steering wheel 210. Depending on the situation, it may include any motor that can be classified as a steering feedback motor, steering assist motor, steering reaction motor, etc.

[0094] The rack 250 is a component included in the lower end of the steering device. Any component that generates changes in steering angle and steering torque by moving the rack 250 can be included.

[0095] The second motor 260 is a configuration included in the lower end of the steering device, and is a configuration that generates rack drive torque based on information related to changes in steering angle and steering torque received from the upper end of the steering device. Depending on the situation, it may include any motor that is classified as a rack motor, rack drive motor, etc.

[0096] The steering device 200 described above may be equipped with a steering control device 100 according to the present invention, and its various components can be controlled by the steering control device 100. Furthermore, these provisions are applicable to the following... Figures 3 to 7 The instructions mentioned above relate to the steering mechanism.

[0097] Figure 3 This is an exemplary diagram illustrating the configuration of a steering system in a vehicle according to an embodiment that enables the steering control device to operate.

[0098] Reference Figure 3 The steering control device 100 can be controlled to make the rack 250 and the second motor 260 work in accordance with the rotation of the steering wheel 210, and can be controlled to generate steering feedback torque in the first motor 220.

[0099] Specifically, a steering torque 312 can be generated as the steering wheel 210 rotates, and a command for moving the rack 250 can be generated based on the rotation of the steering wheel 210 and the magnitude of the steering torque 312. Accordingly, the command rack speed 314 and the command second motor torque 316 can be calculated.

[0100] Next, it can be controlled to generate motor torque in the second motor 260 based on the command second motor torque 316, and it can be controlled to make the second motor 260 rotate at the second motor speed 352 by the motor torque.

[0101] Next, the rack 250 can be controlled to move at a rack speed 354 based on the operation of the second motor 260 as described above. In this case, the magnitude of the rack speed 354 can be calculated or estimated as the value of multiplying the second motor speed 352 by a preset gear constant.

[0102] Next, when the rack 250 moves at a rack speed 354 via the second motor 260, the rack thrust 356 applied to the rack 250 can be calculated. Here, the rack thrust 356 can be calculated by directly measuring it using a sensor, or it can be calculated by estimating it using the motor torque and speed of the second motor 260, the rack speed of the rack 250, etc.

[0103] Subsequently, the steering control device 100 can be controlled to generate steering feedback torque 322 in the first motor 220 based on rack speed 354 or rack thrust 356.

[0104] Furthermore, the content related to the generation of steering torque 312 caused by the rotation of steering wheel 210 as described above, the generation of command rack speed 314 and command second motor torque 316, the calculation and generation of second motor speed 352, rack speed 354 and rack thrust 356, and the control of the generation of steering feedback torque 322, except for the parts related to steering response lag prevention control, can also be applied to the following. Figure 4 and Figure 5 middle.

[0105] Figure 4 This is a diagram illustrating, by way of example, the steering response lag in the steering system of a vehicle according to one embodiment.

[0106] Reference Figure 4 In the steering control device 100, a large steering torque 412 is generated due to situations such as the rapid rotation of the steering wheel 210. As a result, when an instruction exceeding the capacity limit of the second motor 260 is generated, a steering feedback torque smaller than the magnitude corresponding to the rotation of the steering wheel 210 will occur, which may result in a steering response lag.

[0107] Specifically, when the steering wheel 210 rotates rapidly at a constant speed or higher, the steering torque 412 may become a value greater than a constant value, and the resulting command rack speed 414 and command second motor torque 416 may also be calculated to be relatively large.

[0108] Subsequently, these commands for rack speed 414 and second motor torque 416 may exceed the performance of the second motor 260, and if the second motor 260 is operated based on commands exceeding its performance, the second motor 260 can only operate within the limits of its performance.

[0109] Accordingly, when the second motor 260 is driven and the rack 250 is operated according to the instruction rack speed 414 and the instruction second motor torque 416, the second motor speed 452, rack speed 454 and rack thrust 456 can be set to be smaller than the calculated values ​​generated by the instructions.

[0110] Next, as described above, if the rack speed 454 and rack thrust 456 are generated at a size smaller than the calculated value generated by the command, the magnitude of the steering feedback torque 422 calculated based on the rack speed 454 and rack thrust 456 may also be calculated to be smaller than the size corresponding to the command.

[0111] As a result, according to one embodiment of the steering control device 100, when the steering wheel 210 rotates rapidly at a constant speed or higher, generating a relatively large steering torque 412, and when the rack 250 drives it accordingly, generating a smaller steering feedback torque 422 than the size corresponding to the rotation of the steering wheel 210 due to exceeding the capacity limit of the second motor 260, the driver may feel a reaction force, or a steering response lag phenomenon may occur where the steering cannot be performed at the desired speed.

[0112] In this case, the magnitude of the torque corresponding to the rotation of the steering wheel 210, in relation to the steering feedback torque 422, can be the magnitude of the steering response hysteresis torque 424 added to the steering feedback torque 422.

[0113] That is, when a relatively large steering torque 412 is generated due to the rotation of the steering wheel 210, if a torque corresponding to the magnitude of the summed steering feedback torque 422 and the steering response lag torque 424 is generated on the first motor 220, steering response lag can be prevented.

[0114] Figure 5 A diagram illustrating the configuration of steering response hysteresis prevention control in the steering device of a vehicle according to an embodiment is provided.

[0115] Reference Figure 5 When the steering control device 100 generates a relatively large steering torque 512 due to a situation such as a rapid rotation of the steering wheel 210, it generates a command that exceeds the capacity limit of the second motor 260. Figure 4 In contrast, the allowable rack speed 558 is calculated based on the performance information of the second motor, and the first motor 220 is controlled to generate a steering response lag prevention torque based on the allowable rack speed 558, thereby preventing steering response lag.

[0116] Specifically, when the steering wheel 210 rotates rapidly at a constant speed or higher, the steering torque 512 generated by it may become a value of constant magnitude or higher, and the resulting command rack speed 514 and command second motor torque 516 may also be calculated to be large values.

[0117] However, compared to directly driving the rack 250 and the second motor 260 based on the commanded rack speed 514 and the commanded second motor torque 516... Figure 4 In a different embodiment, the steering control device 100 determines whether the command rack speed 514 is a command that exceeds the limit of the second motor capacity, and calculates the portion exceeding the limit of the second motor capacity as a damping torque. Furthermore, it generates a steering response lag prevention torque by adding it to the steering feedback torque, thereby preventing the occurrence of steering response lag.

[0118] For example, the steering control device 100 can calculate the allowable rack speed information based on the prior rack thrust information 552 and the second motor performance information. Here, the prior rack thrust information 552 may include information storing a measured or estimated value of the rack thrust acting on the rack 250 in the state prior to generating the steering torque 512 and the commanded rack speed 514.

[0119] In more detail, the steering control device 100 can calculate the permissible second motor torque 554 based on the previous rack thrust information 552 and the second motor performance information. For example, based on the previous rack thrust information 552 and the first lookup table information, when a rack thrust corresponding to the magnitude of the previous rack thrust information 552 is applied to the rack 250, the permissible second motor torque 554 related to the motor torque allowed by the performance limitations of the second motor can be calculated. Furthermore, these permissible second motor torques 554 can be calculated as corresponding motor torque information.

[0120] Next, the steering control device 100 can calculate the corresponding motor speed information based on the corresponding motor torque information and the second motor performance information. For example, based on the allowed second motor torque 554 and the second lookup table information, when a motor torque corresponding to the allowed second motor torque 554 is applied to the second motor, a permissible second motor speed 556 related to the motor speed allowed by the performance limitations of the second motor can be calculated. Furthermore, these permissible second motor speeds 556 can be used as the corresponding motor speed information for calculation.

[0121] Here, the allowable second motor torque 554 and corresponding motor torque information, and the allowable second motor speed 556 and corresponding motor speed information can be information calculated in the process of calculating the allowable rack speed information for pre-judging whether steering response lag occurs, before the rack 250 and the second motor 260 are actually driven.

[0122] Next, the steering control device 100 can calculate the permissible rack speed 558 based on the corresponding motor speed information and a preset gear constant. Alternatively, the rack speed difference 559 can be calculated by using the difference between the commanded rack speed 514 and the permissible rack speed 558.

[0123] Next, the steering control device 100 can calculate the damping torque 524 based on the commanded rack speed 514, the permissible rack speed 558, the rack speed difference 559, and information from the third lookup table. For example, it searches for (queries) the value corresponding to the permissible rack speed 558 from the index of the permissible rack speed in the third lookup table, and searches for the value corresponding to the rack speed difference 559 from the index of the rack speed difference in the third lookup table, thereby calculating the damping torque 524 by retrieving the damping torque value stored at the corresponding position.

[0124] Then, the steering control device 100 can be controlled to calculate the steering response lag prevention torque by adding the magnitude of the steering feedback torque 522 calculated by the existing logic and the damping torque 524, and generate a torque corresponding to the steering response lag prevention torque on the first motor 220, thereby performing steering response lag prevention control.

[0125] Furthermore, during the execution of these steering response lag prevention controls, steering response lag prevention controls can be executed if the condition that the rack speed difference 559, which is related to the difference between the commanded rack speed 514 and the permissible rack speed 558, is at least a preset reference speed difference is met.

[0126] Alternatively, by calculating the dead zone information, including the upper and lower dead zone limits, if the command rack speed 514 exceeds the upper dead zone limit while the steering response lag prevention control is not being executed, the system can be controlled to execute steering response lag prevention control. Conversely, if the command rack speed 514 is less than the lower dead zone limit while the steering response lag prevention control is being executed, the system can be controlled to terminate the execution of steering response lag prevention control.

[0127] In this way, by using reference speed difference or dead zone information to meet preset conditions related to steering response lag prevention control, steering response lag prevention control can be performed, thereby improving the control efficiency of steering control device 100 and further improving the stability of steering control, including steering response lag prevention control.

[0128] As mentioned above Figure 5 As described in the relevant description, the steering control device 100 according to the present invention determines in advance whether the magnitude of the command rack speed 514 generated by the rapid rotation of the steering wheel 210 exceeds the performance of the second motor. Therefore, it calculates the allowable rack speed 558 and damping torque 524 in advance before driving the rack 250 and the second motor 260, thereby controlling it to generate steering response hysteresis prevention torque in the second motor 260.

[0129] That is, by comparing the command information and the performance information of the second motor, the probability of the occurrence of steering response lag can be determined. If the probability of the occurrence of steering response lag is determined, preemptive measures for steering response lag prevention control can be implemented. Therefore, when compared with the case of implementing ex-post measures to realize steering response lag, it has the effect of improving the occurrence of steering response lag and the steering instability and steering control inefficiency that occur in the process of removing it.

[0130] Figure 6 This is a diagram illustrating, by way of example, the configuration of a steering control device according to one embodiment using performance information of a second motor.

[0131] Reference Figure 6 According to one embodiment, the performance information of the second motor of the steering control device may include performance-related information at the time of design of the second motor. In this case, the performance-related information of the second motor may include not only information related to motor torque and motor speed, but also information related to rack thrust and rack speed, which may affect the performance of the second motor when it is connected to a rack.

[0132] Specifically, the performance information of the second motor can be Figure 6The chart format shown can also be Figure 7 The lookup table form shown can also be a calculation form that can output a corresponding output value when an input value is input.

[0133] As an example, the performance information of the second motor may include rack thrust-motor torque information related to the relationship between the rack force and motor torque of the second motor.

[0134] Specifically, the rack thrust-motor torque information may include information representing the relationship between the rack thrust value applied to the rack in a steering device where a second motor and a rack are connected, and the rack thrust value applied to the rack when a motor torque corresponding to a specific motor torque value is applied to the second motor. That is, it may include information enabling the calculation of the shape of the rack thrust value corresponding to the motor torque value of the second motor, or the shape of the motor torque value of the second motor corresponding to the rack thrust value.

[0135] Furthermore, this rack thrust-motor torque information can be presented in a graphical format, with rack thrust and motor torque each representing an axis. Alternatively, it can be presented in a tabular format, with rack thrust and motor torque each representing an index. (See below for an example.) Figure 7 As explained, in order to distinguish it from other lookup table information, when the rack thrust-motor torque information is in lookup table form, it is set as the first lookup table information.

[0136] As another example, the performance information of the second motor may include motor torque-motor speed information related to the TN curve of the second motor. Here, the TN curve is information related to the relationship between the motor's torque and the number of cycles, where the number of cycles is revolutions per minute, which can include information related to the motor's rotational speed.

[0137] Specifically, the motor torque-motor speed information can be information that represents the relationship between the motor torque and motor speed of the second motor in a graphical form. For example, it could be information in a graphical form with motor torque as the x-axis and motor speed as the y-axis.

[0138] Alternatively, the motor torque-motor speed information could be represented as a lookup table, using the motor torque value of the second motor as an index to store the motor speed value corresponding to each motor torque value. Furthermore, as follows: Figure 7 As explained, in order to distinguish it from other lookup table information, when the motor torque-motor speed information is in lookup table form, it is set as the second lookup table information.

[0139] As another example, the performance information of the second motor may include rack speed-damping torque information related to the relationship between the rack speed and damping torque of the second motor.

[0140] Specifically, the rack speed-damping torque information can be represented as a lookup table, where the commanded rack speed and the permissible rack speed are used as indices to store the damping torque values ​​corresponding to the commanded rack speed and the permissible rack speed. Alternatively, it can be represented as a table, where the permissible rack speed and the rack speed difference are used as indices to store the damping torque values ​​corresponding to the permissible rack speed and the rack speed difference.

[0141] Alternatively, the rack speed-damping torque information can be represented as a lookup table, in which the allowed rack speed is used as one index and the rack speed difference, which is related to the difference between the commanded rack speed and the allowed rack speed, is used as another index, storing the corresponding damping torque values.

[0142] As another example, rack speed-damping torque information can be presented in a graphical format, with the allowable rack speed, rack speed difference, and damping torque each representing an axis. Furthermore, as follows... Figure 7 As explained in the text, in order to distinguish it from other lookup table information, when the rack speed-damping torque information is in lookup table form, it is set as the third lookup table information.

[0143] On the other hand, the steering control device 100 according to one embodiment can be based on Figure 6 The motor torque-motor speed graph in the image is used to calculate motor torque-motor speed information, and this information can be used to calculate the motor speed value corresponding to a specific motor torque value, or the motor torque value corresponding to a specific motor speed value.

[0144] Additionally, it can be based on Figure 6 The graph shows the motor torque-motor speed, and the relationship between the second motor's torque and rack thrust. This allows for the calculation of rack thrust-motor torque information, and can be based on... Figure 6 The graph shows the motor torque-motor speed and the relationship between the second motor's speed and rack speed. The motor speed-rack speed information is then calculated.

[0145] As an example, Figure 6The Y-axis of the graph shown serves as a reference, representing information related to the relationship between the motor torque value and the specific rack thrust value. That is, in the case where the second motor generates torque corresponding to a specific motor torque value, thereby causing the rack to operate, when a rack thrust corresponding to a specific rack thrust value is applied, this correspondence between the specific motor torque value and the specific rack thrust value can be used to calculate rack thrust-motor torque information.

[0146] As another example, Figure 6 The X-axis of the graph shown serves as a reference, representing information related to the relationship between the rack speed value and the specific motor speed value. That is, when a second motor operates at a speed corresponding to a specific motor speed value, thereby causing the rack to operate, the motor speed-rack speed information can be calculated using this correspondence between the specific motor speed value and the specific rack speed value, given the resulting rack speed.

[0147] Taking all the above explanations into account Figure 6 Based on the graphs and the relationship between motor torque and motor speed, the relationship between rack thrust and motor torque, and the relationship between motor speed and rack speed, the steering control device 100 calculates the motor torque value corresponding to a specific rack thrust value, the motor speed value corresponding to a specific motor torque value, and the rack speed value corresponding to a specific motor speed value.

[0148] Furthermore, in connection with this, when specifically referring to Figure 6 When looking at the graphs, the relationship between the motor torque and motor speed of the second motor can be defined as a relationship that is closer to an inverse relationship as the motor speed decreases, so that the motor torque can be increased in a more reasonable way.

[0149] but, Figure 6 The charts may include, by exception, the intervals in which the motor speed is constant in all cases where the motor torque is constant; and the intervals in which the motor torque is constant in all cases where the motor speed is constant.

[0150] Taking into account these exceptional ranges, when the rack thrust information is below the preset critical thrust information 610, the preset critical rack speed information 620 is calculated as the allowable rack speed information.

[0151] Here, in Figure 6 In the chart, within the range where the motor speed value does not increase below a constant value regardless of the increase in the motor torque value, the critical thrust information 610 can be set to the motor torque value corresponding to the motor speed value and the rack thrust value corresponding to the motor torque value at the maximum position.

[0152] Furthermore, in this case, the critical rack speed information 620 can determine the motor speed value corresponding to the critical thrust information 610, and can calculate the rack speed value corresponding to the motor speed value based on the relationship between the motor speed and the rack speed.

[0153] In summary, when the critical thrust information 610 and the critical rack speed information 620 are preset, the critical rack speed information can be calculated as the allowable rack speed information without additional complex calculations when the rack thrust is above the critical thrust. Therefore, the overall calculation speed of the allowable rack speed information can be improved.

[0154] In addition, Figure 6 In another exception to the chart, namely all cases where the motor speed is below a constant value, if the range where the motor torque has a constant value is used, then when the rack speed information is below the preset second critical rack speed information 630, the preset second critical rack thrust information 640 can be calculated as rack thrust information.

[0155] Figure 7 This is an exemplary diagram illustrating the configuration of a steering control device utilizing a lookup table according to one embodiment.

[0156] Reference Figure 7 The second motor performance information is information related to the relationship between at least two or more pieces of information, and may include information in the form of a lookup table, in which a specific value related to at least one or more pieces of information is used as an index, and the specific value corresponding to the remaining information is stored.

[0157] Specifically, when the rack thrust-motor torque information, motor torque-motor speed information, and rack speed-damping torque information are each implemented using a lookup table, in order to distinguish between the various lookup tables, the rack thrust-motor torque information can be defined as the first lookup table information, the motor torque-motor speed information can be defined as the second lookup table information, and the rack speed-damping torque information can be defined as the third lookup table information.

[0158] As an example, the first lookup table information may include information related to the first lookup table. In the first lookup table, each rack thrust value is used as an index, and the motor torque value corresponding to each rack thrust value is stored respectively.

[0159] Specifically, when using the information in the first lookup table, a specific rack thrust value can be used as an index to calculate the motor torque value corresponding to the specific rack thrust value, or a specific motor torque value can be used as an index to calculate the rack thrust value corresponding to the specific motor torque value.

[0160] As another example, the second lookup table information may include information related to the second lookup table, in which each motor torque value is used as an index and the motor speed value corresponding to each motor torque value is stored.

[0161] Specifically, when using the information from the second lookup table, a specific motor torque value can be used as an index to calculate the motor speed value corresponding to that specific motor torque value, or a specific motor speed value can be used as an index to calculate the motor torque value corresponding to that specific motor speed value.

[0162] As another example, the third lookup table information may include information related to the third lookup table, in which each rack speed value is used as an index and a damping torque value corresponding to each rack speed value is stored.

[0163] Specifically, by utilizing the information from the third lookup table, specific rack speed values ​​and specific rack speed differences can be used as indices to calculate the corresponding damping torque values.

[0164] In summary, in the steering control device according to the present invention, when calculating motor torque, motor speed, damping torque, etc., calculations are performed using formulas related to the input / output relationship of the required information in each calculation. However, it is also possible to utilize... Figure 7 The information shown in the lookup table format is used to calculate the required value.

[0165] Thus, when a lookup table is used in the calculation process of the present invention, the calculation speed of multiple values ​​required in steering response lag prevention control can be improved, thereby improving the substantial effect of steering response lag prevention control.

[0166] In other words, based on the rotation state of the steering wheel, the steering response lag prevention torque must be calculated in advance before generating the steering feedback torque corresponding to that rotation state in order to effectively exert the actual steering response lag prevention effect. When this is taken into account, the usefulness of applying lookup tables in the calculation process of this invention can be maximized.

[0167] The steering control device 100 will be briefly described again from a methodological point of view below. Content that is repeated above will be omitted as needed, but all of them are applicable to the following methodological point of view.

[0168] Figure 8 This is a sequence diagram related to the steering control method of the present invention.

[0169] Reference Figure 8The steering control method according to the present invention may include: a step of allowing rack speed information calculation S810; a step of calculating steering response hysteresis prevention torque information S820; and a step of steering response hysteresis prevention control S830.

[0170] As an example, a steering control method is used to control a first motor and a second motor corresponding to the rotation of a steering wheel. The first motor generates steering feedback torque, and the second motor generates rack drive torque for moving the rack. The steering control method includes: a step of calculating allowable rack speed information, which calculates allowable rack speed information based on rack thrust information and preset second motor performance information, the allowable rack speed information being related to the rack speed allowed when the rack is driven using the second motor; a step of calculating steering response hysteresis prevention torque information, which calculates steering response hysteresis prevention torque information for preventing steering response hysteresis (catch-up) on the steering wheel based on commanded rack speed information and the allowable rack speed information, the commanded rack speed information being generated to drive the rack at a speed corresponding to the rotation of the steering wheel; and a steering response hysteresis prevention control step, which performs steering response hysteresis prevention control on the first motor based on the steering response hysteresis prevention torque information.

[0171] The allowable rack speed information calculation step S810 may include the following steps: calculating the allowable rack speed information based on rack thrust information and second motor performance information.

[0172] Specifically, the allowable rack speed information calculation step S810 may include the following steps: calculating the corresponding motor torque information and corresponding motor speed information corresponding to the rack thrust information based on the second motor performance information, and calculating the allowable rack speed information based on the corresponding motor torque information and corresponding motor speed information.

[0173] As an example, the rack speed information calculation step S810 may include the following steps: calculating the corresponding motor torque information based on the first lookup table information included in the rack thrust information and the rack thrust-motor torque information.

[0174] Next, the rack speed information calculation step S810 may include the following steps: calculating the corresponding motor speed information based on the second lookup table information included in the corresponding motor torque information and the motor torque-motor speed information.

[0175] Next, in the allowable rack speed information calculation step S810, the rack speed information can be calculated based on the relationship between the motor speed of the second motor and the rack speed, using a method that calculates the rack speed corresponding to the motor speed when the second motor is driven at the corresponding motor speed. For example, it can include the following step: calculating the allowable rack speed information by multiplying the corresponding motor speed information with a preset gear constant.

[0176] The steering response hysteresis prevention torque information calculation step S820 may include the following steps: calculating steering response hysteresis prevention torque information based on command rack speed information and allowable rack speed information.

[0177] Specifically, in the steering response lag prevention torque information calculation step S820, the damping torque information can be calculated based on the command rack speed information and the allowable rack speed information, and the calculation is performed by adding the steering feedback torque and damping torque information calculated by the existing logic that does not consider whether the steering response lag is present.

[0178] Steering response hysteresis prevention control step S830 may include: performing steering response hysteresis prevention control on the first motor based on steering response hysteresis prevention torque information. In this case, steering response hysteresis prevention control may include: controlling the first motor by generating steering response hysteresis prevention torque based on steering response hysteresis prevention torque information.

[0179] In addition, in the steering response lag prevention control step S830, steering response lag prevention control can be performed if either the reference speed difference or the dead zone interval information meets a preset condition.

[0180] Figure 9 This is an exemplary diagram illustrating the general process for calculating the final torque in a steering control method according to one embodiment.

[0181] Reference Figure 9 The process for calculating the final torque in the steering control method according to one embodiment may include a rack thrust input step S910, a rack speed command input step S920, a rack speed calculation permission step S930, a dead zone handling step S940, a damping torque calculation step S950, an existing control logic execution step S960, a totaling step S970, and a final torque calculation step S980.

[0182] The rack thrust input step S910 may include the step of inputting previously measured or estimated rack thrust information into the steering control device 100.

[0183] The instruction rack speed input step S920 may include the step of inputting instruction rack speed information generated corresponding to the rotation of the steering wheel into the steering control device 100.

[0184] The allowable rack speed calculation step S930 may include a step of calculating allowable rack speed information based on rack thrust information and commanded rack speed information. In this case, the allowable rack speed information may be calculated based on second motor performance information related to the performance of the second motor at the time of its design.

[0185] In addition, the performance information of the second motor may include information related to the TN curve of the second motor. That is, it allows the rack speed information to be calculated based on the TN curve of the second motor.

[0186] In the dead band processing step S940, a dead band including an upper dead band value and a lower dead band value can be set based on the allowable rack speed information. Dead band processing is used to determine whether the command rack speed information exceeds the dead band and to determine whether to execute steering response lag prevention control.

[0187] Specifically, it may include the following steps: if the command rack speed information exceeds the upper limit of the dead zone when steering response lag prevention control is not performed, then steering response lag prevention control is started; if the command rack speed information is less than the lower limit of the dead zone when steering response lag prevention control is performed, then steering response lag prevention control is terminated.

[0188] The damping torque calculation step S950 may include the following steps: if the dead zone processing result satisfies the execution conditions of steering response lag prevention control, the damping torque information is calculated based on the command rack speed, the allowed rack speed information, and the rack speed-damping torque information.

[0189] For example, the value corresponding to the allowable rack speed and rack speed difference information can be found from the index of the preset third lookup table, and the damping torque information can be calculated by using the method of extracting the damping torque value stored at the corresponding position.

[0190] The existing control logic execution step S960 may include the following steps: executing logic to calculate steering feedback torque and control it in response to the rotation of the steering wheel.

[0191] The total step S970 may include a step for adding the damping torque information and the steering feedback torque.

[0192] The final torque calculation step S980 may include a step of calculating the final torque using the result of adding the magnitude of the steering feedback torque and the magnitude of the damping torque. Here, the final torque may refer to the steering response lag prevention torque generated in the first motor to prevent steering response lag.

[0193] Figure 10 This is a sequence diagram used to illustrate a steering control method according to yet another embodiment.

[0194] refer to Figure 10 According to another embodiment of the steering control method, it may include a rack speed limiting setting step S1010, a damping torque index signal calculation step S1020, a damping torque calculation step S1030, and a feedback torque output step S1040.

[0195] The rack speed limiting setting step S1010 may include the following steps: based on rack thrust information and second motor performance information, when rack thrust corresponding to rack thrust information is applied to the rack, setting the maximum value of rack speed that is limited by the performance limit of the second motor, i.e., limiting rack speed.

[0196] The damping torque index signal calculation step S1020 may include the following steps: based on the limiting rack speed and the second motor curve table, calculate the index signal corresponding to the limiting rack speed from the second motor curve table.

[0197] In this case, the second motor curve table may include curve information related to the performance of the second motor. For example, information related to the TN curve of the second motor may include information in a table format.

[0198] Additionally, the damping torque index signal calculation step S1020 may include a step of performing dead zone processing based on limiting the rack speed.

[0199] Specifically, the steps may include: setting a dead zone with an upper and lower limit based on the rack speed limit, and determining whether to execute steering response lag prevention control by using dead band processing to determine whether the commanded rack speed exceeds the dead zone.

[0200] The damping torque calculation step S1030 may include: calculating damping torque information from a second motor curve table using a damping torque index signal. In this case, it may include the following steps: the damping torque index signal may be used during the extraction of the corresponding value from the index portion of the second motor curve table, thereby extracting the damping torque value stored at the storage location of the index corresponding to the damping torque index signal, and thus calculating the damping torque information.

[0201] The feedback torque output step S1040 may include a step for outputting the final feedback torque to the first motor. Specifically, the feedback torque output step S1040 may include the following steps: calculating the final feedback torque by adding the damping torque information and the steering feedback torque calculated by existing logic, based on the damping torque information and the steering feedback torque, and outputting the final feedback torque to the first motor based on the calculation result.

[0202] Through the above, even when commands exceeding the performance limits of the second motor are generated due to rapid rotation of the steering wheel, the damping torque is calculated using the second motor curve table related to the performance of the second motor and the rack speed limit, and the final feedback torque is output to the first motor by adding the steering feedback torque generated by the existing logic to the damping torque, thereby executing steering response lag prevention control that can prevent steering response lag from occurring.

[0203] As described above, the present invention can provide a steering control device and a steering control method that can prevent steering response lag caused by motor capacity limitations.

[0204] In addition, the present invention can provide a steering control device and a steering control method that can predict the possibility of steering response lag based on command information and motor information generated by the rotation of the steering wheel.

[0205] The above description is merely an illustrative representation of the technical concept of the present invention. Those skilled in the art can make various modifications and variations without departing from the essential characteristics of this technical concept. Furthermore, this embodiment is intended to illustrate the technical concept of the present invention and not for limiting purposes; therefore, the scope of this technical concept is not limited to this embodiment. The scope of protection of the present invention should be interpreted by the scope of the following claims, and all technical concepts within the same scope should be interpreted as being included within the scope of the claims of the present invention.

Claims

1. A steering control device for controlling a first motor and a second motor corresponding to rotation of a steering wheel, wherein the first motor generates steering feedback torque and the second motor generates rack drive torque for moving a rack, characterized in that, include: The calculation unit calculates permissible rack speed information based on rack thrust information and preset second motor performance information. This permissible rack speed information relates to the rack speed allowed when the second motor is used to drive the rack. The calculation unit also calculates steering response lag prevention torque information based on commanded rack speed information and the permissible rack speed information to prevent steering response lag on the steering wheel. The commanded rack speed information is generated to drive the rack at a speed corresponding to the rotation of the steering wheel. The control unit performs steering response hysteresis prevention control on the first motor based on the steering response hysteresis prevention torque information. The calculation unit calculates rack speed difference information related to the difference between the magnitude of the commanded rack speed information and the magnitude of the allowed rack speed information. When the rack speed difference information is above a preset reference speed difference, the control unit performs the steering response lag prevention control.

2. The steering control device according to claim 1, characterized in that, The calculation unit calculates the corresponding motor torque information and the corresponding motor speed information corresponding to the rack thrust information based on the second motor performance information, and calculates the allowable rack speed information based on the corresponding motor torque information and the corresponding motor speed information.

3. The steering control device according to claim 2, characterized in that, The second motor performance information includes: The first lookup table information uses each rack thrust value as an index to store the motor torque value corresponding to each rack thrust value, and... The second lookup table information uses each motor torque value as an index to store the motor speed value corresponding to each motor torque value; The calculation unit calculates the corresponding motor torque information based on the rack thrust information and the first lookup table information, and calculates the corresponding motor speed information based on the corresponding motor torque information and the second lookup table information.

4. The steering control device according to claim 2, characterized in that, The calculation unit calculates the allowable rack speed information by multiplying the corresponding motor speed information by a preset gear constant.

5. The steering control device according to claim 1, characterized in that, When the rack thrust information is below a preset critical thrust information, the calculation unit calculates the preset critical rack speed information as the allowable rack speed information.

6. The steering control device according to claim 1, characterized in that, The second motor performance information includes a third lookup table, in which the rack speed value is used as an index to store the damping torque value corresponding to each rack speed value. The calculation unit calculates the damping torque information based on the command rack speed information, the allowable rack speed information, and the third lookup table information, and calculates the steering response hysteresis prevention torque information based on the steering feedback torque and the damping torque information.

7. The steering control device according to claim 1, characterized in that, The calculation unit sets the upper and lower dead zone limits based on the allowable rack speed information and calculates the dead zone interval information. When the command rack speed information exceeds the dead zone interval below the upper limit of the dead zone and above the lower limit of the dead zone, the control unit performs the steering response lag prevention control based on the dead zone interval information.

8. A steering control method for controlling a first motor and a second motor, corresponding to rotation of a steering wheel, wherein the first motor generates steering feedback torque, and the second motor generates rack drive torque for moving a rack, characterized in that, include: The allowed rack speed information calculation step calculates allowed rack speed information based on rack thrust information and preset second motor performance information. This allowed rack speed information is related to the permitted rack speed when the second motor is used to drive the rack. The steering response hysteresis prevention torque information calculation step calculates steering response hysteresis prevention torque information to prevent steering response hysteresis on the steering wheel based on the commanded rack speed information and the allowed rack speed information. The commanded rack speed information is generated to drive the rack at a speed corresponding to the rotation of the steering wheel. The steering response lag prevention control step involves performing steering response lag prevention control on the first motor based on the steering response lag prevention torque information. The steering response hysteresis prevention torque information calculation step includes the following steps: Calculate rack speed difference information related to the difference between the magnitude of the commanded rack speed information and the magnitude of the allowed rack speed information. The steering response hysteresis prevention control steps include the following steps: If the rack speed difference information is above the preset reference speed difference, the steering response lag prevention control is executed.

9. The steering control method according to claim 8, characterized in that, The calculation steps for the allowable rack speed information include the following steps: Based on the second motor performance information, the corresponding motor torque information and corresponding motor speed information corresponding to the rack thrust information are calculated, and the allowable rack speed information is calculated based on the corresponding motor torque information and the corresponding motor speed information.

10. The steering control method according to claim 9, characterized in that, The second motor performance information includes: The first lookup table information uses each rack thrust value as an index to store the motor torque value corresponding to each rack thrust value, and... The second lookup table information uses each motor torque value as an index to store the motor speed value corresponding to each motor torque value; The calculation steps for the allowable rack speed information include the following steps: The corresponding motor torque information is calculated based on the rack thrust information and the first lookup table information, and the corresponding motor speed information is calculated based on the corresponding motor torque information and the second lookup table information.

11. The steering control method according to claim 8, characterized in that, The calculation steps for the allowable rack speed information include the following steps: When the rack thrust information is below a preset critical thrust information, the preset critical rack speed information is calculated as the allowable rack speed information.

12. The steering control method according to claim 8, characterized in that, The second motor performance information includes a third lookup table, in which the rack speed value is used as an index to store the damping torque value corresponding to each rack speed value. The steering response hysteresis prevention torque information calculation step also includes the following steps: The damping torque information is calculated based on the command rack speed information, the allowable rack speed information, and the third lookup table information, and the steering response hysteresis prevention torque information is calculated based on the steering feedback torque and the damping torque information.

13. The steering control method according to claim 8, characterized in that, The steering response hysteresis prevention torque information calculation step includes the following steps: Based on the allowable rack speed information, the upper and lower dead zone limits are set, and the dead zone interval information is calculated. The steering response hysteresis prevention control steps include the following steps: If the command rack speed information exceeds the dead zone of the dead zone information, the steering response lag prevention control is executed.

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