Steering control device and steering control method

Abstract

Steering control device (10) comprising: a receiver (110) that receives engine torque from an engine torque sensor provided in a host vehicle; and a control device (120) that makes it possible to drive a steering gear in a compliance zone, to calculate a friction of the steering gear based on the engine torque obtained by driving the steering gear, to determine a state of the steering gear based on the calculated friction and to issue a notification to a driver about the state of the steering gear, where the compliance zone is set to a range of engine positions in which a rack does not move even though the steering gear is driven. wherein the control device (120) controls the steering gear so that it is driven in the compliance zone before the host vehicle is steered by the driver, wherein the control device (120) determines that the steering gear is in a normal state when the calculated friction is less than a predetermined first reference value and greater than a predetermined second reference value, characterized in that the control device (120) stores the calculated friction and, if a result of the comparison between stored frictions shows that the friction is gradually increasing, determines that the steering gear has rust formations.

Description

BACKGROUND

[0001] The present invention relates to a steering control device according to the preamble of claim 1 and to a steering control method according to the preamble of claim 5. Area: Description of related technology

[0002] The electric steering device detects the steering torque generated by the rotation of the steering wheel and controls the motor so that it provides steering assistance proportional to the detected steering torque, thereby controlling the steering of the vehicle.

[0003] In electronic power steering, the steering torque generated by turning the steering wheel is transmitted to the rack via the rack-and-pinion mechanism, and the power steering assistance generated by the motor, which depends on the steering torque, is also transmitted to the rack. In other words, the power steering assistance generated by the motor is added to the steering torque generated by the steering wheel, causing the rack to move axially and thus steering the vehicle.

[0004] In such an electronic power steering system, a reduction in friction between several components, e.g., the rack and pinion mechanism or the reduction gear of the mechanism comprising the device, can occur, for example, due to wear on the components or decreasing fastening force, which can occur with increasing vehicle mileage. Another example is that the rack and pinion mechanism or the reduction gear can develop rust, thereby increasing friction between several parts of the mechanism. A method for detecting increased friction in a servo-assisted rack and pinion steering system, in which an electric servo motor is coupled to a rack and pinion of the steering system via a ball screw drive, is known from the generic publication DE 10 2014 201 952 A1.In this process, the electric servomotor of the rack and pinion steering system is supplied with a test current of a predetermined current strength, and any change in the position of a rotor of the electric servomotor resulting from this current is recorded. The recorded change in position is then compared with a predetermined expected change in position, and a friction state is determined based on the result. Further methods for determining a changed friction state are known from DE 10 2013 220 519 A1 and DE 10 2018 217 474 A1.

[0005] An increase or decrease in friction between the internal components of the electronic power steering system can cause the driver to experience an unpleasant sensation when steering.

[0006] The aforementioned problems are solved by a steering control device with the features of claim 1, and by a steering control method with the features of claim 5. Possible embodiments are set forth in the dependent claims. In one aspect, the disclosure provides for a steering control device which, in particular, comprises a receiver that receives engine torque from an engine torque sensor provided in a host vehicle, and a control device that enables a steering gear to be driven within a compliance zone, which calculates the friction of the steering gear based on the engine torque received by driving the steering gear, determines a state of the steering gear based on the calculated friction, and outputs a message to a driver regarding the state of the steering gear.

[0007] In another aspect, the disclosure provides for a steering control method which includes, in particular, an information reception step that receives an engine torque from an engine torque sensor provided in a host vehicle, a friction calculation step that enables a steering gear to be driven in a compliance zone and that calculates a friction of the steering gear based on the engine torque received by the drive of the steering gear, and a state determination step that determines a state of the steering gear based on the calculated friction.

[0008] According to the disclosure, the steering control device and the method can calculate and quantify the friction of the steering gear and determine the condition of the steering gear according to the calculated friction. DESCRIPTION OF THE DRAWINGS

[0009] The foregoing and further tasks, features and advantages of the disclosure will become clearer from the following detailed description when it is taken into account together with the accompanying drawings, in which: Fig. 1 is a block diagram illustrating a steering control device according to an embodiment of the disclosure; Fig. 2 a schematic representation of a steering control system according to an exemplary embodiment; Fig. 3 and Fig. Four views are shown, illustrating an example of calculating friction using a compliance zone according to an embodiment; Fig. 5 is a flowchart illustrating a steering control procedure according to an embodiment of the disclosure; Fig. 6 is a flowchart that illustrates step S520 in more detail according to an exemplary embodiment; and Fig. Figure 7 is a view that shows step S530 in more detail according to an exemplary embodiment. DETAILED DESCRIPTION

[0010] In the following description of examples or embodiments of the disclosure, reference is made to the accompanying drawings, which show specific examples or embodiments that can be implemented for illustrative purposes and in which the same reference numerals and symbols can be used to designate the same or similar components, even if they are shown in different accompanying drawings. Furthermore, in the following description of examples or embodiments of the disclosure, detailed descriptions of known functions and components included herein are omitted where it is determined that such a description might make the subject matter rather unclear in some embodiments of the disclosure.The expressions used herein, such as "contain," "exhibit," "include," "consist of," and "formed of," are generally intended to permit the addition of other components, unless the expressions are used with the phrase "only." As used herein, singular forms are intended to include plural forms unless the context clearly indicates otherwise.

[0011] Expressions such as “first,” “second,” “A,” “B,” “(A),” or “(B)” may be used herein to describe elements of revelation. None of these terms are used to define any importance, order, sequence, or number of elements, etc., but are used merely to distinguish the respective element from other elements.

[0012] When it is mentioned that a first element is "connected or coupled" to a second element, or that it "touches or overlaps," this should be interpreted to mean that the first element may be "directly connected or coupled" to the second element, or that it may "directly touch or overlap," but also that a third element may be "arranged between" the first and second elements, or that the first and second elements may be "connected or coupled" to each other via a fourth element, or that they may "touch or overlap," etc. In this context, the second element may be contained within at least one of two or more elements that are "connected or coupled," "touch or overlap," etc.

[0013] When time-related terms such as "after", "following", "next", "before" and the like are used to describe processes or operations of elements or configurations or of sequences or steps in operational, processing and manufacturing procedures, these terms may be used to describe non-consecutive or non-sequential processes or operations unless the term "immediately" or "as soon as" is used together.

[0014] Furthermore, when specifying dimensions, relative sizes, etc., it should be considered that numerical values ​​for an element or feature, or corresponding information (e.g., level, range, etc.), include a tolerance or error range that can be caused by various factors (e.g., process factors, internal or external influences, noise, etc.), even if no specific description is provided. Moreover, the term "could" can encompass all meanings of the term "may."

[0015] A steering control device according to an embodiment of the disclosure is described below with reference to the accompanying drawings.

[0016] Fig. Figure 1 is a block diagram illustrating a steering control device 10 according to an embodiment of the disclosure.

[0017] Referring to Fig. 1 A steering control device 10 according to an embodiment of the disclosure can comprise a receiver 110 and a control device 120.

[0018] According to one embodiment of the disclosure, the steering control device 10 may be an advanced driver assistance system (ADAS) installed in a host vehicle to provide information that is helpful for driving the host vehicle or assists the driver in the host vehicle.

[0019] The term ADAS can refer to various types of driver assistance systems. These systems can include, for example, autonomous emergency braking, a parking assist system (SPAS), blind spot detection (BSD), adaptive cruise control (ACC), lane departure warning system (LDWS), lane keeping assist system (LKAS), and lane change assist system (LCAS). However, the disclosure is not limited to these.

[0020] In this context, "host vehicle" can refer to a vehicle equipped with a drive motor and powered by its force. Furthermore, the host vehicle can be an electric vehicle, i.e., an electrically powered vehicle that obtains its propulsion energy not by burning a fossil fuel, but by powering a motor with electricity from a battery.

[0021] The steering control device 10 is suitable for both manned vehicles and driverless, autonomous vehicles.

[0022] The receiver 110 can receive engine torque from an engine torque sensor present in the host vehicle.

[0023] The engine torque sensor described above can be mounted on the host vehicle. In one embodiment, the engine torque sensor can be integrated into the steering control system 1.

[0024] An embodiment of the steering control system 1 is described below, in which the functions of the steering control device 10 can be performed.

[0025] Fig. Figure 2 is a schematic view of a steering control system 1 according to an exemplary embodiment.

[0026] In relation to Fig. 2. According to one embodiment, the steering control system 1 can be a system in which the steering of the vehicle equipped with the steering control system 1 is controlled depending on the rotation angle of the steering wheel 211 operated by the driver.

[0027] The steering control system 1 can comprise a hydraulic power steering system (HPS), which generates hydraulic pressure by rotating a pump to produce a steering assistance force, and an electronic power steering system (EPS), which drives a motor to produce a steering assistance force. The following description focuses primarily on the electronic steering control system 1, but the disclosure is not limited to it.

[0028] The steering control system 1 can be a mechanical steering control system 1 that steers the wheel 223 by transmitting the force (torque) generated by the driver turning the steering wheel 211 to the steering motor 221 (reference numeral 231 in the figure) via a mechanical power transmission device (e.g. a linkage). Fig. 2) transmits to steer the wheel 223 by means of the drive of the steering motor 221, or a steer-by-wire (SbW) system that transmits the force by transmitting / receiving electrical signals, e.g., via a cable, instead of a mechanical force transmission device, depending on whether the steering input actuator 210 and the steering output actuator 220 are coupled by a mechanical connecting element (or linkage). An example is described below in which the steering control 1 is an SbW system, but the disclosure is not limited thereto.

[0029] The in Fig. The steering control system 1 shown in the disclosure can comprise a steering input actuator 210, a steering control device 10, and a steering output actuator 220. As described above, the steering input actuator 210 and the steering output actuator 220 can be mechanically separated from each other if the steering control system 1 is a SbW system.

[0030] The steering input actuator 210 can refer to a device into which the steering information intended by the driver is input. As described above, the steering input actuator 210 can include a steering wheel 211, a steering shaft 212, and a reaction force motor 213. Although not shown, the steering angle information can also include a steering gear to transmit the rotational force of the reaction force motor 213 to the steering shaft 212.

[0031] The reaction force motor 213 can receive a control signal (also referred to as a "command current") from the steering control device 10 and exert a reaction force on the steering wheel 211. In particular, the reaction force motor 213 can receive a command current from the steering control device 10 and drive it at a rotational speed specified by the command current, thereby generating a reaction torque. The generated reaction torque can be transmitted to the steering wheel via the steering gear.

[0032] The steering control device 10 can receive steering information from the steering input actuator 210, calculate a control value, and output an electrical signal indicating the control value to the steering output actuator 220. The steering information can be information that includes at least a steering angle or a torque.

[0033] The steering control device 10 can receive performance information as feedback, which is actually output by the steering output actuator 220, calculate a control value and output an electrical signal based on the control value to the steering output actuator 220 to provide the driver with a steering feel.

[0034] The steering output actuator 220 can be a device that actually drives the steering of the host vehicle. The steering output actuator 220 can, for example, comprise a steering motor 221, a rack 222, and a wheel 223.

[0035] The steering input actuator 210 and the steering output actuator 220 can also include a motor torque sensor that can detect the motor torque of the reaction force motor 213 and the steering motor 221.

[0036] The steering motor 221 can move the rack 222 axially. In particular, the steering motor 221 can be driven by receiving a command current from the steering control device 10 and move the rack 222 linearly in the axial direction. The wheel 223 can be steered to the left or right by the linear movement of the rack 222.

[0037] Although not shown, the steering control system 1 according to the disclosure may also include, for example, a clutch for disconnecting or connecting the steering input actuator 210 and the steering output actuator 220. The clutch can be actuated by the steering control device 10.

[0038] If the steering control system 1 according to the disclosure is an SbW system and the host vehicle is driving in an autonomous driving mode, the steering control system 1 according to the disclosure can either control only the steering output actuator 220 to control the steering of the host vehicle, or control both the steering input actuator 210 and the steering output actuator 220 to control the steering of the host vehicle.

[0039] Returning to Fig. 1. The control device 120 can enable the steering gear to be driven in the compliance zone, calculate the friction of the steering gear based on the engine torque obtained by driving the steering gear, determine the state of the steering gear based on the calculated friction, and issue a notification about the state of the steering gear to the driver.

[0040] The control device 120 can estimate the rack force based on information about the motor torque from the receiver 110. The estimated rack force can be derived from the sum of the friction of the steering gear, the friction of the vehicle's suspension, and the friction of the tires. Determining the condition of the steering gear therefore requires an environment in which only the friction of the steering gear can be calculated.

[0041] Fig. 3 and Fig. Figure 4 shows an example of calculating friction using a compliance zone according to an embodiment.

[0042] According to the Fig. 3 and Fig. 4. The friction of the steering gear can be calculated by driving the steering gear within the compliance zone. The compliance zone can be set to a range of motor positions in which the rack does not move, even when the steering gear is driven. In particular, the steering gear can be driven by the steering motor, which is controlled by the command signal from the steering control device 10, and the rack can thus move. However, there may be a small range in which the rack does not move, even though the steering gear is driven by the steering motor, and such a small range can be defined as the compliance zone.

[0043] As in Fig. As shown in Figure 3, the compliance zone can be set to a range of motor positions. Motor position can refer to the angle at which the motor rotates clockwise or counterclockwise. Thus, the compliance zone can be defined based on a preset motor rotation angle.

[0044] The range of motor positions in which the rack remains stationary, even though the steering gear is driven by the steering motor, can vary depending on the mechanical characteristics of the steering gear. Accordingly, the compliance range can be defined differently depending on the mechanical characteristics of the steering gear.

[0045] Referring to Fig. 4. The control device 120 can receive the motor torque generated by the steering motor via the steering gear drive from the motor torque sensor in order to calculate an estimate of the torque. The calculated estimate of the torque can be displayed in the Fig. The diagram shown in section 4 illustrates this.

[0046] In Fig. 4. A and B can each be the maximum and minimum values ​​of the torque estimate, but are not limited to this. For example, in a segment where the motor position is constant, the torque estimate can be varied, in which case A and B can each be the mean of the varied torque estimates.

[0047] The control device 120 can calculate the friction of the steering gear based on A and B. For example, the friction of the steering gear can be the average value obtained by dividing A and B by 2.

[0048] Accordingly, it is possible to calculate the estimated torque based on the torque generated by the steering motor when the steering gear is driven in the compliance zone, so that the rack does not move, and to calculate the steering gear friction based on this estimated torque. When the steering gear is driven in the compliance zone, the actual position of the rack remains unchanged, so only internal components of the steering gear are actuated without influencing suspension and tire friction. This allows for the creation of an environment in which only the steering gear friction can be calculated.

[0049] The compliance zone is not limited to the position of the rack. In other words, wherever the rack is positioned, if its position lies at the midpoint between the forces, it is possible to calculate the steering gear friction, since the steering gear is driven within the compliance zone based on the rack being positioned midway between the forces. In other words, even if the rack is not positioned at the midpoint, the steering gear is driven within the compliance zone as long as its position does not deviate from the midpoint between the forces, allowing the steering gear friction to be calculated.

[0050] The control device 120 can control the steering gear so that it moves into the compliance zone before the host vehicle is steered by the driver, calculating the friction of the steering gear and determining the state of the steering gear based on this calculated friction. For example, the control device 120 can control the steering gear so that it moves into the compliance zone before the host vehicle starts and steers, thus determining the state of the steering gear. As another example, the control device 120 can control the steering gear so that it moves into the compliance zone before the host vehicle, which has previously been moving and stopped so that its speed is zero, steers again, thereby determining the state of the steering gear.

[0051] As described above, the control device 120 can determine the state of the steering gear based on the calculated friction of the steering gear. Various embodiments of the steering gear state determined from the calculated friction of the steering gear are described below.

[0052] If the calculated friction is, for example, a preset first reference value or higher, the control unit 120 can detect that the steering gear is damaged. The preset first reference value may be the maximum value at which the steering gear can be driven without damage. In this case, the control unit 120 can issue a message to the driver indicating damage to the steering gear.

[0053] As another example, receiver 110 can receive the temperature from a temperature sensor located in the host vehicle. The received temperature can be the interior temperature of the host vehicle, but is not limited to this. The temperature can, for example, be the temperature of the external environment in which the host vehicle is moving.

[0054] If the calculated friction is equal to or greater than the preset first reference value, and the received temperature is equal to or less than the preset temperature, the control unit 120 can detect that the steering gear is experiencing increased friction due to low temperature. In other words, the grease applied to the steering gear bearing, for example, may undergo a change in its physical properties due to the low temperature, resulting in increased steering gear friction. In this case, the control unit 120 can send a message to the driver indicating that the steering gear friction has increased due to low temperature. The control unit 120 can then initiate additional control measures to increase the power of the steering motor to compensate for the increased steering gear friction caused by the low temperature.

[0055] As described above, if the calculated friction corresponds to or exceeds the preset first reference value and the temperature is preset as a factor for determining the condition of the steering gear, the control device 120 can detect and determine an increase in steering gear friction due to damage to the steering gear or a low temperature based on the temperature received from the temperature sensor and issue a notification or message to the driver about the result of the determination.

[0056] Another example is that if the calculated friction is below a preset second reference value, the control unit 120 may detect that the steering gear is worn. The preset second reference value can be the maximum value at which parts need to be replaced due to wear on the steering gear. In this case, the control unit 120 can issue a message to the driver indicating that parts need to be replaced due to wear on the steering gear.

[0057] As another example, if the calculated friction is less than the preset first reference value and greater than the preset second reference value, the control device 120 can determine that the steering gear is in a normal state. In other words, the range between the preset first and second reference values ​​can be a numerical friction range within which the steering gear can normally operate. In this case, the control device 120 can issue a message indicating that the steering gear is normal, but in a normal state, no message may be issued.

[0058] Furthermore, the control device 120 can detect, based on the calculated friction, that the steering gear has developed rust, even though it is operating within the normal range for normal driving. For example, the control device 120 can calculate the friction of the steering gear when the steering gear is operating within the compliance zone and store the calculated friction values. The control device 120 can compare the stored friction values ​​and, if the comparison shows that the friction is gradually increasing, determine that the steering gear has developed rust. In other words, if rust forms and the condition deteriorates, the friction of the steering gear can gradually increase. The control device 120 can detect that the steering gear has developed rust by storing and comparing the calculated friction values.In this case, the control unit 120 can issue a message to the driver that a repair is required due to rust deposits on the steering gear.

[0059] As described above, the steering control device 10 can calculate the friction of the steering gear according to the disclosure and determine the condition of the steering gear according to the calculated value.

[0060] The steering control device 10 can, for example, be designed as an electronic control unit (ECU).

[0061] According to one embodiment, a computer system (not shown), such as the steering control device 10, can be implemented as an electronic control unit (ECU). The ECU can include at least one or more processors, memory, a storage unit, a user interface input unit, or a user interface output unit, which can communicate with each other via a bus. The computer system can also include a network interface for accessing a network. The processor can be a central processing unit (CPU) or a semiconductor device that executes processing instructions stored in the memory and / or storage unit. The memory and storage unit can comprise various types of volatile / non-volatile storage media. For example, the memory can include read-only memory (ROM) and random-access memory (RAM).

[0062] The following describes a steering control method using the steering control device 10, which can perform the embodiments described above in the disclosure.

[0063] Fig. Figure 5 is a flowchart illustrating a steering control procedure according to an embodiment of the disclosure.

[0064] Referring to Fig. 5. A steering control method according to the disclosure may include an information reception step S510 for receiving an engine torque from an engine torque sensor provided in a host vehicle, a friction calculation step S520 for enabling a steering gear to be driven in a compliance zone and for calculating a friction of a steering gear based on an engine torque received by driving or controlling the steering gear, and a state determination step S530 for determining a state of the steering gear based on the calculated friction.

[0065] Although not shown, the steering control procedure may further include an output step (not shown) to issue a notification to a driver about the state of the steering gear determined in state determination step S530.

[0066] Fig. Figure 6 is a flowchart that illustrates step S520 in more detail according to an exemplary embodiment.

[0067] With reference to Fig. 6. The steering control method can determine whether the rack of the host vehicle is positioned at a midpoint between the forces. The midpoint between forces can indicate a balance of forces. Therefore, if the rack is positioned at the midpoint between forces, it may be in a state where no external force acts upon it.

[0068] The steering control method can control the steering gear so that it is driven within the compliance zone (S620). The compliance zone can be set to a range of engine positions in which the rack does not move, even when the steering gear is driven. Generally, the estimated torque can represent the sum of the steering gear friction, the vehicle's suspension friction, and the tire friction. When the steering gear is driven within the compliance zone, the rack does not move, making it possible to calculate the steering gear friction solely based on the estimated torque.

[0069] The steering gear drive can be controlled to enter the compliance zone before the driver steers the host vehicle. For example, it is possible to control the steering gear so that it is driven within the compliance zone before the host vehicle starts moving and steering, or before the host vehicle, which has previously moved and stopped (so that its speed is zero), begins steering again.

[0070] The steering control procedure can calculate the friction of the steering gear (S630). For example, the steering control procedure can calculate the estimate of the torque by receiving from the engine torque sensor the engine torque generated by the steering motor through the drive of the steering gear when the steering gear is driven in the compliance zone, and calculate the friction of the steering gear based on the calculated estimate of the torque.

[0071] Fig. Figure 7 is a view that shows step S530 in more detail according to an exemplary embodiment.

[0072] As in Fig. As shown in Figure 7, the steering control procedure can determine whether the calculated friction is equal to or greater than a preset first reference value (S710). If the calculated friction is equal to or greater than the preset first reference value (Yes in S710), the information receive step can continue to receive the temperature from the temperature sensor provided in the host vehicle, and the condition determination step can determine whether the temperature received from the temperature sensor is equal to or less than a preset temperature (S720). If the temperature received from the temperature sensor is equal to or less than a preset temperature (Yes in S720), the steering control procedure can determine that the steering gear condition is an increase in friction due to low temperature (S730). In this case, the steering control procedure can issue a message to the driver that the steering gear friction has increased due to low temperature, although this is not shown in Figure 7. Fig. Figure 7 is not shown. The steering control procedure can perform an additional control to increase the power of the steering motor in order to compensate for the increased friction of the steering gear due to the low temperature.

[0073] If the temperature received by the temperature sensor is above the preset temperature, the steering control procedure may detect that the steering gear has been damaged (S740). In this case, the Fig. If 7 is not shown, the steering control system can issue a message to the driver about the damage to the steering gear.

[0074] If the calculated friction is less than the preset first reference value (No in S710), the steering control procedure can determine whether the calculated friction is equal to or less than a preset second reference value (S750).

[0075] If the calculated friction is equal to or less than the preset second reference value (Yes in S750), the steering control procedure may detect that the steering gear is worn (S760). In this case, although in Fig. 7 not shown, issue a message to the driver informing him that a part replacement is necessary due to wear and tear on the steering gear.

[0076] If the calculated friction is greater than the preset second reference value (No in S750), the steering control procedure can determine that the steering gear is in a normal condition (S770). In this case, which is described in Fig. If 7 is not shown, the steering control procedure may issue a message indicating that the steering gear is normal, but in the normal state, the output of a message may be omitted.

[0077] Furthermore, the steering control procedure, although in Fig.Figure 7 (not shown) indicates that the steering gear has developed rust based on the calculated friction, even though the steering gear is operating within the normal range for normal driving. For example, the steering control system can calculate the steering gear friction when the steering is operating within the compliance zone, store the calculated friction values, and, if a comparison of the stored friction values ​​shows a gradual increase in friction, determine that the steering gear has developed rust. In this case, the steering control system can issue a message to the driver indicating that repair is required due to rust deposits on the steering gear.

[0078] As described above, the steering control device and steering control method can only calculate and quantify the friction of the steering gear and determine the state of the steering gear according to the calculated friction.

[0079] The above description is presented to enable the person skilled in the art to implement and utilize the technical idea of ​​the disclosure and has been provided in the context of a specific application and its requirements. Various modifications, additions, and substitutions to the described embodiments will be readily apparent to a person skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the intent and scope of the disclosure. The above description and the accompanying drawings provide an example of the technical idea of ​​the disclosure for purely illustrative purposes. That is to say, the disclosed embodiments are intended to illustrate the scope of the technical idea of ​​the disclosure.Thus, the scope of the disclosure is not limited to the embodiments shown, but refers to the broadest scope consistent with the claims. The scope of protection of the disclosure should be interpreted on the basis of the following claims, and all technical ideas within the scope of their equivalents should be considered to be included in the scope of the disclosure.

Claims

[1] Steering control device (10) comprising: a receiver (110) that receives engine torque from an engine torque sensor provided in a host vehicle; and a control device (120) that makes it possible to drive a steering gear in a compliance zone, to calculate a friction of the steering gear based on the engine torque obtained by driving the steering gear, to determine a state of the steering gear based on the calculated friction and to issue a notification to a driver about the state of the steering gear, where the compliance zone is set to a range of engine positions in which a rack does not move even though the steering gear is driven. wherein the control device (120) controls the steering gear so that it is driven in the compliance zone before the host vehicle is steered by the driver, wherein the control device (120) determines that the steering gear is in a normal state when the calculated friction is less than a predetermined first reference value and greater than a predetermined second reference value, characterized by , that the control device (120) stores the calculated friction and, if a result of the comparison between stored frictions shows that the friction is gradually increasing, determines that the steering gear has signs of rust. [2] Steering control device (10) according to claim 1, characterized by , that the control device (120) detects that the steering gear is damaged when the calculated friction is a preset first reference value or higher. [3] Steering control device (10) according to claim 1 or 2, characterized by, that the receiver (110) further receives a temperature from a temperature sensor provided in the host vehicle, and wherein the control device (120) determines that the condition of the steering gear is an increase in friction due to a low temperature when the calculated friction is a preset first reference value or more and the temperature is a preset temperature or less. [4] Steering control device (10) according to one of claims 1 to 3, characterized by , that the control device (120) determines that the steering gear is worn when the calculated friction is a preset second reference value or less. [5] Steering control procedures, including: an information reception step (S510) that receives an engine torque from an engine torque sensor provided in a host vehicle; a step for calculating friction (S520) which makes it possible to drive a steering gear in a compliance zone and to calculate the friction of the steering gear based on the engine torque obtained by driving the steering gear; and a state determination step (S530) that determines a state of the steering gear based on the calculated friction, where the compliance zone is set to a range of engine positions in which a rack is not moved even though the steering gear is driven, wherein the state determination step (S530) controls the steering gear so that it is driven in the compliance zone before the host vehicle is steered by the driver, wherein the state determination step (S530) determines that the steering gear is in a normal state when the calculated friction is less than a predetermined first reference value and greater than a predetermined second reference value, characterized by , that the state determination step (S530) stores the calculated friction and, if a result of the comparison between stored frictions shows that the friction is gradually increasing, determines that the steering gear is rusting. [6] Steering control method according to claim 5, characterized by , that the condition determination step (S530) determines that the steering gear is damaged if the calculated friction is a preset first reference value or higher. [7] Steering control method according to claim 5 or 6, characterized by, that the information reception step (S510) further receives a temperature from a temperature sensor provided in the host vehicle, and wherein the state determination step (S530) determines that the state of the steering gear is an increase in friction due to a low temperature when the calculated friction is a preset first reference value or more and the temperature is a preset temperature or less. [8] Steering control method according to any one of claims 5 to 7, characterized by , that the condition determination step (S530) determines that the steering gear is worn if the calculated friction is one preset second reference value or less.

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