Steering device, steering control device, abnormality detection method for steering device, and program

Abstract

The steering device (700) has: a movable member (26); a housing (50); a motor (5); a rotation-linear motion conversion mechanism (70); an elastic body (80, 80) that elastically supports the rotation-linear motion conversion mechanism to the housing; and a control device (500) that, according to a case where a condition as a trigger or the like is established, outputs a first control signal (SG20) for relatively moving the rotation-linear motion conversion mechanism with respect to the movable member by a displacement amount corresponding to an elastic support amount of the elastic body to the motor, acquires a physical quantity related to a movement amount of the movable member based on the first control signal, judges whether or not there is an abnormality based on the physical quantity related to the movement amount of the movable member, and outputs an abnormality judgment signal when it is judged that there is an abnormality.

Description

Technical Field

[0001] This invention relates to steering devices, steering control devices, methods and procedures for detecting abnormalities in steering devices, etc. Background Technology

[0002] Patent document 1 shows a steering device that has an abnormality diagnosis function that diagnoses the presence or absence of abnormal conditions by detecting faults and anomalies.

[0003] Claim 1 of the document describes that "the steering actuator drive command signal includes a steering drive command signal and an abnormality detection test drive command signal, the test drive command signal is output to the steering actuator to steer the steering wheel, and the abnormality diagnosis unit determines whether there is an abnormality in the steering device based on the signal related to the action performed by the steering actuator in response to the test drive command signal".

[0004] Furthermore, claim 7 of the document states that "the controller includes a steering angle detection unit, which detects the steering angle of the steering wheel based on a signal related to the action of the steering actuator corresponding to the test drive command signal."

[0005] Furthermore, claim 9 of the document states that "in the steering device of claim 7, a test drive command signal causes the steering wheel to move and reach the end of the stroke on the left and right sides of the steering wheel."

[0006] In addition, paragraph

[0175] of the document states that "abnormalities can be diagnosed by detecting abnormal phenomena such as a decrease in motor speed and periodic fluctuations in motor speed."

[0007] Furthermore, in the anomaly diagnosis of this literature, the steering wheel needs to be moved significantly when detecting faults or anomalies. Therefore, if there are obstacles such as curbs around the steering wheel, the movement of the steering wheel will be hindered, making accurate anomaly detection impossible. As a countermeasure, paragraphs

[0108] and

[0109] of this literature or Figure 8 As described in step S22, as a prerequisite for anomaly detection, images of the area around the steering wheel are captured using a camera or similar device to detect the presence of obstacles.

[0008] In, for example, paragraph

[0007] of patent document 2, Figure 2 The diagram illustrates a steering device comprising: a steering shaft capable of axial movement; a ball screw that transmits driving force generated by an electric motor to the steering shaft; a bearing that rotatably supports the nut of the ball screw in a housing; and an elastomer that supports the bearing axially on the steering shaft.

[0009] Paragraph

[0042] of this document describes "axial deformation of the elastic body along the steering shaft", and paragraph

[0003] of this document describes "the elastic body has the effect of reducing vibration and working noise caused by the axial displacement of the bearing, or attenuating the impact load acting on the bearing along the axial direction".

[0010] In a passage

[0004] of Patent Document 3, it is described that "in a steering device, when a load is applied to the rack, the transmission part of the reducer that slows down the output rotation of the steering motor undergoes elastic deformation, and the position of the steering component and the rotation position of the steering motor will deviate according to the amount of elastic deformation, thereby causing a control error in the steering angle."

[0011] Furthermore, as a countermeasure, the document describes, for example, paragraph

[0022] , that "in order to suppress the decrease in steering angle control accuracy caused by elastic deformation of the transmission part of the reducer, the microcomputer includes a load estimation unit and a load compensation amount calculation / judgment unit."

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent Application Publication No. 2020-37315

[0015] Patent Document 2: International Publication No. 2020 / 170417

[0016] Patent Document 3: Japanese Patent Application Publication No. 2023-38726 Summary of the Invention

[0017] The problem that the invention aims to solve

[0018] In Patent Document 1, the steering actuator is activated according to a test drive command signal, and the steering actuator's faults and abnormalities are detected by detecting the steering angle of the steering wheel.

[0019] In addition, when detecting faults or abnormalities, the steering wheels are moved to the end of their travel on the left and right sides of the steering wheel.

[0020] In this case, the travel distance of the steering shaft, i.e., the stroke, becomes longer, and the time required to detect the steering angle also becomes longer.

[0021] Furthermore, as described in Patent Documents 2 and 3, it is known that elastic deformation can occur in steering devices where there is an elastic body that shifts axially along the steering axis, or in the transmission part of a speed reducer.

[0022] However, as described in Patent Document 3, elastic deformation of the transmission part of the reducer is considered to be one of the causes of control error in steering angle.

[0023] In other words, this elastic deformation is considered to be the main reason for the adverse effect on the control accuracy of the steering angle. Therefore, in Patent Document 3, a compensation process is implemented by computer to compensate for the reduction in control accuracy.

[0024] In other words, in the past, the elastic deformation of the transmission parts of the reducer did not contribute to the detection of abnormalities in the steering device.

[0025] The purpose of this invention is to reduce the amount of travel and time required for detecting the following anomalies: the normal movement of movable parts such as steering shafts is constrained by factors such as rust or icing.

[0026] Methods for solving problems

[0027] The inventors conducted in-depth research and obtained the following insights: During the period when the driving force for anomaly detection is applied to a movable part such as a steering shaft, the amount of travel of the temporary and reversible small displacement caused by the elastic body or the like is different in the case of an anomaly and in the case of no anomaly. Therefore, it is possible to determine whether there is an anomaly based on this small displacement.

[0028] This invention is based on these insights.

[0029] The following is an explanation of this disclosure.

[0030] According to one aspect of this disclosure, a steering device (700) is provided, which is installed in a vehicle to steer the vehicle's steering wheels (31, 31), wherein the steering device (700) comprises: a movable member (26) connected to the steering wheels and steer them; a housing (50) covering at least a portion of the movable member and fixed to the vehicle body; a motor (5) applying a steering force to the movable member; a rotary-to-linear conversion mechanism (70) disposed within the housing, which converts the rotary motion transmitted from the motor into linear motion and transmits it to the movable member; and an elastomer (80, 80) disposed within... Between the rotary direct-acting conversion mechanism and the housing, the rotary direct-acting conversion mechanism is elastically supported in the housing; and the control device (500), which, in response to the condition for triggering as an action confirmation or the condition for a predetermined condition being met, outputs a first control signal (SG20) to the motor, causing the rotary direct-acting conversion mechanism to move relative to the movable part relative to the displacement amount corresponding to the elastic support amount of the elastic body, obtains a physical quantity related to the movement amount of the movable part based on the first control signal, and determines whether there is an abnormality based on the physical quantity related to the movement amount of the movable part, and outputs an abnormality judgment signal (SG35) when an abnormality is determined.

[0031] According to another aspect of this disclosure, a steering control device (500) is provided that controls the operation of a steering device (700), which is mounted on a vehicle (10) and turns the steering wheels of the vehicle. The steering device includes: a movable part (26) connected to and turning the steering wheels (31, 31); a housing (50) covering at least a portion of the movable part and fixed to the vehicle body; a motor (5) applying a steering force to the movable part; a rotary-to-linear conversion mechanism (70) disposed within the housing, which converts the rotational motion transmitted from the motor into linear motion and transmits it to the movable part; and an elastic body (80, 80) disposed between the rotary-to-linear conversion mechanism and the housing, elastically supporting the rotary-to-linear conversion mechanism in the housing, or a transmission mechanism (44) disposed between the motor and the rotary-to-linear conversion mechanism, which transmits the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism. The transmission mechanism (44) includes a deformable driving medium (63) and an elastic body (80, 80). An anomaly detection process is implemented to detect abnormalities in the normal movement of a movable part. The anomaly detection process includes: a first process, generating an anomaly detection driving force by providing an anomaly detection drive command to a motor, and applying the anomaly detection driving force to the movable part. Although the anomaly detection driving force cannot cause the movable part to move over the frictional force acting on the movable part, it can cause temporary and reversible deformation of the elastic body, or cause temporary and reversible deformation of the driving medium and the elastic body, which are assumed to be deformable; and a second process, measuring the minute displacement of the movable part and obtaining the measured value of the physical quantity corresponding to the minute displacement. If the first stroke amount corresponding to the minute displacement shown by the measured value is smaller than the second stroke amount corresponding to the normal minute displacement generated under no anomaly conditions, an anomaly is determined to exist. The minute displacement corresponds to the deformation of the elastic body, or the total deformation of the driving medium and the elastic body, which are assumed to be deformable, during the application of the anomaly detection driving force to the movable part.

[0032] According to other aspects of this disclosure, a method for detecting anomalies in a steering control device is provided, which detects anomalies in a steering device (700), the steering device being mounted on a vehicle (10) and turning the vehicle's steering wheels. The steering device includes: a movable part (26) connected to and turning the steering wheels (31, 31); a housing (50) covering at least a portion of the movable part and fixed to the vehicle body; a motor (5) applying a steering force to the movable part; a rotary-to-linear conversion mechanism (70) disposed within the housing, converting rotational motion from the motor into linear motion and transmitting it to the movable part; and an elastic body (80, 80) disposed between the rotary-to-linear conversion mechanism and the housing, elastically supporting the rotary-to-linear conversion mechanism within the housing, or a transmission mechanism (44) disposed between the motor and the rotary-to-linear conversion mechanism, transmitting the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism. The transmission mechanism (44) includes a deformable drive medium (63) and an elastic body (80, 80). The anomaly detection method includes: a first step of generating an anomaly detection driving force by providing an anomaly detection driving command to a motor, and applying the anomaly detection driving force to a movable part. Although the anomaly detection driving force cannot cause the movable part to move against the frictional force acting on the movable part, it can cause the elastic body to undergo temporary and reversible deformation, or cause the driving medium and the elastic body, which are assumed to be deformable, to undergo temporary and reversible deformation respectively; and a second step of measuring the minute displacement of the movable part and obtaining the measured value of the physical quantity corresponding to the minute displacement. If the first stroke amount corresponding to the minute displacement shown by the measured value is smaller than the second stroke amount corresponding to the normal minute displacement generated under no anomaly conditions, an anomaly is determined to exist. The minute displacement corresponds to the total deformation of the elastic body temporarily generated during the application of the anomaly detection driving force to the movable part, or the deformation of the driving medium and the elastic body, which are assumed to be capable of the deformation.

[0033] According to another aspect of this disclosure, a program is provided for operating a computer as the tear control device of the present invention described above.

[0034] Invention Effects

[0035] According to the present invention, instead of mechanically moving movable parts such as steering shafts according to the usual viewpoint, the focus is on the extremely small displacement caused by the deformation of the elastic body, and the abnormality is determined based on the small displacement.

[0036] By using an anomaly detection method that is fundamentally different from the past, the stroke of the moving parts required for anomaly detection and the time required for anomaly detection can be significantly reduced compared to the past.

[0037] In addition, according to the present invention, a steering control device capable of detecting abnormalities in the steering device at high speed based on minute displacements can be provided.

[0038] In addition, according to the present invention, a method for detecting steering device abnormalities can be provided, which is capable of detecting steering device abnormalities at high speed based on minute displacements.

[0039] In addition, according to the present invention, a program is provided that enables the easy construction of a steering control device using a computer. Attached Figure Description

[0040] Figure 1 This is a diagram illustrating an example of the overall structure of a steering system according to an embodiment of the present invention.

[0041] Figure 2 It is shown Figure 1 A diagram showing other configuration examples of the steering control device.

[0042] Figure 3 This is a cross-sectional view of an example of a rotary-to-linear conversion mechanism using a ball screw.

[0043] Figure 4 This is a characteristic diagram showing the relationship between the compressive load and the amount of compression of an elastomer.

[0044] Figure 5 This is a cross-sectional view showing an example of a transmission mechanism using a worm and a worm wheel, which has components capable of elastic deformation.

[0045] Figure 6 This is a characteristic graph showing an example of the displacement of the motor rotation angle relative to time under normal conditions during self-diagnostic processing.

[0046] Figure 7 This is a characteristic graph illustrating an example of the displacement of the motor rotation angle relative to time under abnormal conditions during self-diagnostic processing.

[0047] Figure 8 The figure shows a comparison between the motor rotation angle and the time required for anomaly detection in the self-diagnostic process of one embodiment of the present invention and a conventional example.

[0048] Figure 9 This diagram illustrates a case where obstacles such as curbs are present near the steering wheels, but the self-diagnostic process determines it to be normal.

[0049] Figure 10 This diagram illustrates an example of a decision-making process when an obstacle such as a curb that contacts the steering wheel is detected during the self-diagnosis process.

[0050] Figure 11This is a flowchart illustrating an example of the overall processing sequence for self-diagnostic procedures.

[0051] Figure 12 This is a flowchart illustrating an example of the processing steps for determining whether a self-diagnostic process can be implemented.

[0052] Figure 13 This is a flowchart illustrating an example of the specific steps involved in a self-diagnostic process.

[0053] Figure 14 This is a flowchart illustrating another example of the specific processing steps for self-diagnostic procedures. Detailed Implementation

[0054] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments shown in the drawings are one example of the present invention, and the present invention is not limited to this embodiment.

[0055] <Example 1>

[0056] Reference Figure 1 . Figure 1 This is a diagram illustrating an example of the overall structure of a steering system according to an embodiment of the present invention.

[0057] The steering system 200 mounted on the vehicle 10 includes a steering operation input device 300 and a steering device 700. The steering device 700 includes a steering control device 500 and a steering mechanism 800. Furthermore, in this specification, the steering control device is sometimes referred to simply as the "control device".

[0058] Figure 1 The steering system 200 shown is a so-called steer-by-wire type steering system, in which the steering wheel 301 and the steering wheels 31, 31 are mechanically separated, and the steering system 200 can independently control the steering angle of the steering wheels 31, 31 relative to the operating angle of the steering wheel 301.

[0059] The steering operation input device 300 includes a steering wheel 301, a steering shaft 302, an operation angle sensor 303 for detecting the operation angle of the steering wheel 301, an operation torque sensor 304 for detecting the operation torque of the steering wheel 301, and a reaction force actuator, i.e., a reaction force motor 305, for applying a reaction force torque to the steering wheel 301.

[0060] The steering control device 500 may be composed of one or more microprocessors. The steering control device 500 has a control unit 501. The control unit 501 has a motor control unit 403 and an anomaly detection unit 409. The motor control unit 403 has a self-diagnostic capability determination unit 405 and an anomaly detection drive command issuing unit 407. The anomaly detection unit 409 has an anomaly determination unit 411.

[0061] Various sensors 600 and ECU (Electronic Control Unit) 601, which detect the vehicle 10's operating status, driving status, etc., supply the control unit 501 with various information required for the electronic control of the steering device.

[0062] In addition, ECU601 can notify the occupants of vehicle 10, including the driver, of various information by causing the notification unit 603 to operate.

[0063] The steering device 800 includes: a movable member 26 serving as a steering shaft, which is connected to steering wheels 31, 31 via steering knuckle arms 29, 29 and steers the steering wheels 31, 31; a housing 50 covering at least a portion of the movable member 26 and fixed to the body of the vehicle 10; a motor 5 that applies steering force to the movable member 26; a rotary-to-linear conversion mechanism 70 disposed within the housing 50, which converts the rotational motion transmitted from the motor 5 via a transmission mechanism 44 such as a reducer into linear motion and transmits it to the movable member 26; and elastic bodies 80, 80 disposed between the rotary-to-linear conversion mechanism 70 and the housing 50, which elastically support the rotary-to-linear conversion mechanism 70 within the housing 50.

[0064] Furthermore, the motor 5, transmission mechanism 44, rotary-to-direction conversion mechanism 70, and elastic bodies 80 and 80 constitute a steering actuator. However, a steering actuator without the transmission mechanism 44 can also be conceived.

[0065] Elastomers 80 and 80 can be made of rubber parts or wave washers, for example.

[0066] In addition, a rotation angle sensor 2 for detecting the rotation angle of the motor 5 is provided in the steering device 700.

[0067] In addition, Figure 1 In the example, the transmission mechanism 44 has an input-side pulley 61, an output-side pulley 62, and a belt 63 as a driving medium that transmits the rotation of the input-side pulley 61 to the output-side pulley 62 and drives the output-side pulley.

[0068] The belt 63, which serves as the driving medium, is, for example, a ring-shaped belt whose main material is rubber.

[0069] For example, synthetic rubber and polyurethane rubber with excellent wear resistance, oil resistance, heat resistance, and bending resistance can be used. In addition, sometimes glass fiber, steel wire, etc. are embedded inside the 63 as core material.

[0070] By causing the input-side pulley 61 and the output-side pulley 62 to rotate synchronously via the belt 63, which serves as the driving medium, the rotational force of the input-side pulley 61 can be transmitted to the output-side pulley 62.

[0071] The main material of belt 63 is rubber, so slight expansion and contraction can be expected during use. In other words, belt 63 is intended to be a driving medium that deforms during use.

[0072] In addition, Figure 1 In the example, we envision using a ball screw as the rotary-to-linear conversion mechanism 70.

[0073] The ball screw has a nut 73 and a rolling bearing 74. The term "rolling bearing" is sometimes used hereinafter simply referred to as "bearing".

[0074] However, it is not limited to this example. As a rotary-to-linear conversion mechanism 70, a rack and pinion, for example, can be used instead of a ball screw.

[0075] Under normal conditions, the movable component 26, which serves as the steering shaft, can move linearly to the end of its stroke in the first direction DR1 and the second direction DR2, which is opposite to the first direction.

[0076] Furthermore, for example, if the first direction DR1 corresponds to the left when viewed by the occupants of the vehicle 10, including the driver, the "first direction" can also be referred to as the "left." Similarly, if the second direction DR2 corresponds to the left when viewed by the occupants of the vehicle 10, including the driver, the "second direction" can also be referred to as the "right."

[0077] The control unit 501 included in the steering control device 500 can perform necessary calculations based on the detection signal SG1 of the steering angle sensor 303, the detection signal SG2 of the operating torque sensor 304, the detection signals of various sensors 600, and various information supplied from the ECU 601, to generate a control signal SG3 for the reaction motor 305, thereby controlling the reaction torque of the reaction motor 305, and generating a motor control signal SG19, thereby controlling the driving force of the motor 5, such as the steering torque.

[0078] These control functions are typically found in the control unit 500 of a steer-by-wire steering system 200.

[0079] exist Figure 1 In the example, in addition to the usual control functions described above, the control unit 501 also has an anomaly detection function that detects anomalies such as rust, ice, etc., where the normal movement of the movable part 26 is restricted.

[0080] exist Figure 1 In the example, there are obstacles such as rust or ice between the nut 73 and the movable part 26. Therefore, the movable part 26 is in an abnormal state where movement is normally impeded.

[0081] The above-mentioned abnormal state can be detected by activating each part of the abnormal detection unit 409, which includes the self-diagnosis capability determination unit 405, the abnormal detection drive command issuing unit 407, and the abnormal determination unit 411 provided in the motor control unit 403.

[0082] In other words, the steering control device 500 has the following functions: in response to the condition that triggers the action confirmation or the condition that is specified, it outputs a first control signal SG20 to the motor 5, causing the rotary direct motion conversion mechanism 70 to move relative to the movable member 26 by a displacement amount corresponding to the elastic support amount of the elastic body 80, 80, etc.; it acquires a physical quantity related to the movement amount of the movable member 26 based on the first control signal SG20, for example, as a detection signal of the rotation angle sensor 2; it determines whether there is an abnormality based on the physical quantity related to the movement amount of the movable member 26; and when an abnormality is determined, it outputs an abnormality judgment signal SG35 to, for example, the ECU 601.

[0083] exist Figure 1 In the example, the steering device 700 has the following structure: as a structural element that generates temporary and reversible deformation during the provision of a drive command for abnormal detection as a first control signal to the motor 5, in addition to the elastic bodies 80, 80, it also has a belt 63, which is envisioned to deform as a drive medium, provided in the transmission mechanism 44 which is disposed between the motor 5 and the rotary direct drive mechanism 70 and transmits the driving force generated by the rotation of the motor 5 to the rotary direct drive mechanism 70.

[0084] However, it is also conceivable that the transmission mechanism 44 is not provided. In this case, the structural element that undergoes temporary and reversible deformation during the provision of a drive command for anomaly detection as a first control signal to the motor 5 is only the elastic bodies 80, 80.

[0085] It should be noted that, in this specification, a structure that only has elastic bodies 80, 80 as structural elements that produce temporary and reversible deformation is sometimes referred to as the "first structure," while a structure that, in addition to elastic bodies 80, 80, also has a transmission mechanism 44 that is disposed between the motor 5 and the rotary-to-direction conversion mechanism 70 and transmits the driving force generated by the rotation of the motor 5 to the rotary-to-direction conversion mechanism 70, and which is envisioned to be deformable, is referred to as the "second structure."

[0086] As described above, the steering control device 500 includes a motor control unit 403 for controlling the motor 5 and an abnormality detection unit 409 for detecting abnormalities in the normal movement of the movable part 26.

[0087] The summary of the self-diagnostic processing for detecting abnormalities is as follows. First, the self-diagnostic capability determination unit 405 of the motor control unit 403 determines whether self-diagnosis can be performed.

[0088] In a preferred embodiment of the present invention, a self-diagnosis is performed before the vehicle 10 enters a driving state, so as to prevent accidents caused by abnormalities from occurring.

[0089] Therefore, if the self-diagnostic capability determination unit 405 confirms at least one of the following conditions, such as the ignition switch being off, the parking brake being on, the vehicle speed of 10 being zero, or the input of steering commands from occupants including the driver to the motor control unit 403 being cut off, it determines that it is in a state where self-diagnosis can be performed.

[0090] Then, the self-diagnosis capability determination unit 405 turns on the trigger signal required for self-diagnosis processing and the signal indicating the specified conditions, so that the conditions for starting self-diagnosis are met.

[0091] Specifically, the self-diagnostic capability determination unit 405 may input a start signal as a trigger signal to the motor control unit 403 when the ignition switch is on, or when an occupant, including the driver, turns on the self-diagnostic start switch, and at the same time, input a self-diagnostic start signal as a trigger signal to the motor control unit 403.

[0092] Subsequently, the self-diagnosis capability determination unit 405 sends a self-diagnosis start command SG10 to the anomaly detection drive command issuing unit 407, and sends a self-diagnosis start notification signal SG11 to the anomaly detection unit 409 to notify the start of self-diagnosis.

[0093] As a result of implementing these determinations, in a preferred embodiment, the motor control unit 403 and the anomaly detection unit 409 perform a self-diagnostic process to determine whether there is an anomaly when the vehicle 10 is not in motion.

[0094] Therefore, it is possible to perform self-diagnostic anomaly detection before the vehicle 10 is in a driving state, and to prevent accidents and malfunctions caused by the restriction of the movement of movable parts due to rust, ice, etc.

[0095] In addition, for example, when the vehicle 10 is stopped with the ignition switch or other starter switch on, the motor control unit 403 and the abnormality detection unit 409 perform a self-diagnostic process to determine whether there is an abnormality when the vehicle 10 is stopped, for example, when it is in an idling stop state and there is no steering operation input from the occupants of the vehicle 10, including the driver.

[0096] Thus, for example, even during the idling stop of the vehicle 10 while it is in motion, it is possible to perform anomaly determination based on self-diagnosis in advance, even without steering operation input, so as to prevent accidents and malfunctions caused by the restriction of movement of movable parts due to rust, ice, etc.

[0097] Upon receiving the self-diagnosis start command SG10, the abnormal detection drive command issuing unit 407 provides the abnormal detection drive command SG20, which serves as the first control signal, to the motor 5.

[0098] Motor 5 receives the drive command SG for abnormality detection and rotates. As a result, although it is impossible to overcome the friction caused by the sliding resistance in the movable part 26, which is the steering shaft, to move the movable part 26, it will generate a driving force for abnormality detection. This driving force for abnormality detection can cause the belt 63, which is the driving medium that is conceived to deform in the transmission mechanism 44, and the elastic bodies 80 and 80 to deform respectively.

[0099] Furthermore, without the transmission mechanism 44, a driving force for abnormal detection is generated that can cause the elastomers 80 and 80 to deform respectively.

[0100] Here, the deformation of the elastic bodies 80, 80 generated during the application of the driving force for anomaly detection to the movable part 26 is preferably the maximum elastic deformation that each of the elastic bodies 80, 80 can deform. The displacement corresponding to the maximum elastic deformation that each of the elastic bodies 80, 80 can deform can be uniquely specified during the design phase.

[0101] Therefore, it is possible to uniquely predetermine the minute displacement during normal operation.

[0102] Furthermore, the total deformation of the driving medium 63 and the elastic bodies 80, 80, which are temporarily deformable during the period when the driving force for abnormal detection is applied to the movable part 26, is preferably the total deformation obtained by adding the maximum elastic deformation that can be deformed in the elastic bodies 80, 80 to the normal deformation that can be assumed in the driving medium 63 when the driving force for abnormal detection is generated.

[0103] The displacement corresponding to the conceivable normal deformation of the driving medium 63 is uniquely specified during the design phase. Therefore, the minute displacement under normal conditions can be uniquely specified in advance.

[0104] The driving force for abnormality detection is transmitted to the movable part 26 via a reducer that serves as a transmission mechanism 44, thereby applying the driving force for abnormality detection to the movable part 26.

[0105] The anomaly detection unit 409 measures, for example, the minute displacement of the movable part 26 along the first direction DR1 or the second direction DR2 by the rotation angle sensor 2, and obtains a physical quantity corresponding to the minute displacement, such as the measured value of the rotation angle of the motor 5, or in other words, the detection value. The minute displacement corresponds to the deformation of the temporary and reversible elastic bodies 80, 80 generated during the application of the driving force for anomaly detection to the movable part 26, or to the total deformation of the belt 63 and the elastic bodies 80, 80, which are conceived to be deformable as driving mediums.

[0106] The measured value is supplied as the detection signal SG30 of the rotation angle sensor 2 to the anomaly determination unit 411 of the anomaly detection unit 409.

[0107] However, the physical quantity of minute displacement can also be obtained by detecting the rotation angle of the pinion 509 that meshes with the rack, which is a movable part 26, by the rotation angle sensor 510.

[0108] In this case, the detected value of the rotation angle of the pinion 509, in other words, the detection signal SG21, is supplied to the abnormality determination unit 411.

[0109] In addition, the physical quantity of minute displacement can also be obtained by detecting the displacement of the rack, which is a movable part 26, by a non-contact sensor 511.

[0110] exist Figure 1 In this non-contact sensor 511, an optical displacement sensor can be used to apply a mark 513 for position displacement detection on the rack of the movable part 26, which is the object. Light is irradiated from the light-emitting part 515 onto the mark 513, and the reflected light is received by the light-receiving part 517.

[0111] The minute displacement of the movable part 26 can be measured by utilizing the fact that the light-receiving position in the light-receiving part 517 moves according to the displacement of the object, i.e., the movable part 26.

[0112] In this case, the detected value of the displacement detected in the light-receiving unit 517, in other words, the detection signal SG23, is supplied to the anomaly determination unit 411.

[0113] Multiple of the above-mentioned measurement methods can also be used in combination. That is, the measured value of the physical quantity of minute displacement can be at least one of the following: the measured value of the rotation angle of the motor 5, the measured value of the rotation angle of the pinion 509 meshing with the rack as a movable part 26, and the measured value obtained by detecting the displacement of the rack as a movable part 26 through a non-contact sensor 511.

[0114] For example, if the first stroke amount corresponding to the small displacement shown in the received measured value is smaller than the second stroke amount corresponding to the normal small displacement generated in the absence of an anomaly, the anomaly determination unit 411 in the anomaly detection unit 409 determines that there is an anomaly.

[0115] That is, when the normal movement of the movable part (rack) is restricted due to rust, ice, etc., the above-mentioned small displacement will also produce an abnormality in the amount of stroke, so it is possible to determine whether there is an abnormality based on the small displacement.

[0116] In a preferred embodiment, anomaly detection can be implemented through threshold determination.

[0117] Here, if the "stroke amount corresponding to the small displacement based on the measured value" is set as the "first stroke amount" and the "stroke amount of the small displacement that can be imagined under normal conditions" is set as the "second stroke amount", for example, a threshold is set such that the first stroke amount < threshold ≤ second stroke amount. By judging based on this threshold, normal / abnormal conditions can be determined.

[0118] Here, the threshold is less than or equal to the second stroke amount. The maximum range that the threshold can be set is determined by the upper limit of the second stroke.

[0119] Taking this into account, the judgment using the above threshold can also be described as follows: the judgment is that the first stroke corresponding to the measured value is smaller than the second stroke under normal conditions.

[0120] When an anomaly is detected by the anomaly determination unit 411, the anomaly detection unit 403 supplies an anomaly determination signal SG35 to, for example, the ECU 601.

[0121] When the ECU 601 receives the abnormality judgment signal SG35, it can, for example, control the notification unit 603 to issue a notification message to the occupants of the vehicle 10, including the driver, to notify them of the abnormality.

[0122] In addition, to mitigate potential hazards, some functions related to the driving of vehicle 10 can be temporarily disabled, thus temporarily restricting driving functionality. In this manual, these procedures are sometimes referred to as "abnormality countermeasures."

[0123] Thus, in Figure 1 In the example, instead of moving the movable part 26 in a conventional mechanical manner, the focus is on the reversible, extremely small displacement that is temporarily generated during the period when the motor 5 generates the driving force for abnormality detection, corresponding to the drive command for abnormality detection, and the abnormality is determined based on this small displacement.

[0124] As a result, the stroke of the movable part 26 required for anomaly detection can be reduced to less than 1 / 100 of the previous amount compared to the past.

[0125] In addition, unlike existing examples, it does not require detecting abnormal phenomena such as a decrease in motor speed or periodic fluctuations in motor speed. Instead, it can determine abnormalities through simplified threshold determination, which can significantly reduce the burden on the devices required for abnormality determination.

[0126] Furthermore, in the past, since the rack moved and the steering wheel moved significantly, if there were obstacles such as curbs around the steering wheel, the movement of the steering wheel would be hindered and accurate anomaly detection would not be possible. Therefore, as a prerequisite for anomaly detection, it was necessary to first use a camera or the like to take pictures of the area around the steering wheel to detect whether there were obstacles. However, in this invention, the steering wheels 31, 31 do not actually move, so it is not necessary to detect obstacles by taking such pictures, which also reduces the burden on the device.

[0127] However, in this invention, from a microscopic perspective, it is considered that the steering wheel, which corresponds to the tiny displacement of the rack, also has a tiny displacement. Therefore, in cases where the steering wheel is in close contact with the ground, such as when there is a curb or other object, it cannot be said that it will not have an adverse effect on the measurement of the stroke of the tiny displacement in this invention.

[0128] Therefore, in other preferred embodiments of the present invention, countermeasures are also implemented in the case of obstacles such as curbs.

[0129] More specifically, to suppress erroneous judgments caused by adverse effects such as curb stones, a re-diagnosis is implemented. This re-diagnosis is performed in software using anomaly detection algorithms, eliminating the need for camera recording as in the past. This re-diagnosis also reduces the processing load and helps prevent a decrease in anomaly detection accuracy.

[0130] The details of the re-diagnosis will be described later.

[0131] Thus, according to the preferred embodiment of the present invention, the time required for anomaly detection can be significantly reduced, and the processing burden of anomaly determination can be alleviated, thereby simplifying the algorithm for anomaly detection.

[0132] Next, refer to Figure 2 . Figure 2 It is shown Figure 1 Figures showing other structural examples of the steering control device in [the context]. Figure 2 In the middle, to and Figure 1 Common parts are labeled with the same reference numerals.

[0133] Figure 2 The motor control unit 403 shown has the previous Figure 1The self-diagnostic capability determination unit 405 and the abnormality detection drive command issuing unit 407 are shown, but for ease of explanation, these are omitted.

[0134] exist Figure 2 In the example, in addition to the self-diagnosis capability determination unit 405 and the abnormality detection drive command issuing unit 407, the motor control unit 403 also has a motor history accumulation unit 406.

[0135] The motor history accumulation unit 406 stores and accumulates data representing the usage history of the motor 5 at any time, specifically, such as the cumulative value of the rotational speed of the motor 5 or the cumulative value of the usage time of the motor 5.

[0136] In addition, Figure 2 In the example, the anomaly determination unit 411 in the anomaly detection unit 409 is provided with a threshold setting unit 413 and a threshold determination unit 415.

[0137] Historical data is supplied from the motor history accumulation unit 406 to the threshold setting unit 413.

[0138] In addition, the threshold setting unit 413 is supplied with ambient temperature data detected by the temperature sensor 417 of the vehicle 10.

[0139] The threshold setting unit 413 can variably control the threshold for anomaly determination based on at least one of the ambient temperature of the vehicle 10 and the driving history of the vehicle 10.

[0140] The ambient temperature of vehicle 10 can be detected based on the ambient temperature data supplied by temperature sensor 417. In addition, the driving history of vehicle 10 can be detected based on historical data supplied by motor history storage unit 406.

[0141] Here, the belt 63, which serves as the driving medium in the transmission mechanism 44, typically has the following tendency: as the ambient temperature increases, rubber materials and the like tend to stretch, and the degree of stretching of the small displacement generated when the driving force is applied will increase compared to the initial value.

[0142] Furthermore, if the belt 63, which serves as the driving medium in the transmission mechanism 44, continues to be used, the wear and deterioration of the rubber material and the like will cause the elongation of the minute displacement generated when the driving force is applied to differ from the initial value.

[0143] Typically, there is a tendency for the elongation of the small displacement of 63 when the driving force is applied to increase with longer usage time compared to the initial value.

[0144] As described above, the threshold setting unit 413 variably, in other words, adaptively controls the threshold for anomaly determination based on at least one of the ambient temperature of the vehicle 10 and the driving history of the vehicle 10.

[0145] Therefore, the threshold for anomaly detection can be appropriately fine-tuned based on the ambient temperature and usage history.

[0146] The threshold determination unit 415 uses an appropriately adjusted threshold to determine whether there is an anomaly. Therefore, it is possible to suppress the decrease in the accuracy of anomaly determination.

[0147] In addition, Figure 2 In the example, in the control device 500, the memory 503 stores information that enables the computer to function as... Figure 1 or Figure 2 The program 505 is used to make the computer act according to the program 505. By making the computer act according to the program 505, it is easy to construct a steering control device with anomaly detection function based on small displacements.

[0148] Next, refer to Figure 3 . Figure 3 This is a cross-sectional view of a rotary-to-linear conversion mechanism using a ball screw. Figure 3 In the middle, to and Figure 1 Common parts are labeled with the same reference numerals.

[0149] exist Figure 3 In the example, a "ball screw" is used as the rotary-to-linear conversion mechanism 70, and the movable part 26 is a "steering shaft" that turns the wheels 31, 31.

[0150] In the following description, it is sometimes referred to as "ball screw 70" and sometimes as steering shaft 26.

[0151] The ball screw 70 is a type of rotary-to-linear conversion mechanism that converts rotary motion into linear motion.

[0152] The ball screw 70 consists of a threaded portion 71 formed on a movable part 26 that serves as a steering shaft, a plurality of balls 72, and a nut 73 connected to the threaded portion 71 via the plurality of balls 72.

[0153] Nut 73 is an annular component surrounding steering shaft 26 and is configured to rotate relative to steering shaft 26. Nut 73 has a helical groove on its inner circumference, which forms a nut-side ball screw groove. Steering shaft 26 has a helical groove on its outer circumference, which forms a steering shaft-side ball screw groove.

[0154] With the steering shaft 26 inserted into the nut 73, a ball circulation groove is formed by the ball screw groove on the nut side and the ball screw groove on the steering shaft side. The ball circulation groove is filled with a plurality of metal balls 72.

[0155] When the motor 5 rotates, the output pulley 62 rotates through the drive medium 63 of the transmission mechanism 44, and the nut 73 rotates accordingly.

[0156] When the nut 73 rotates, the balls 72 move inside the ball circulation groove, and the steering shaft 26 moves linearly relative to the nut 73 along the axial direction, that is, along the long side. Thus, the rotational motion of the nut 73 is converted into linear motion, that is, into direct motion.

[0157] The housing 50 is composed of a first housing 51 and a second housing 52, which are fixed together by bolts.

[0158] Nut 73 is rotatably supported on housing 50 by bearing 74, and its relative axial movement with respect to bearing 74 is restricted.

[0159] The bearing 74 is located inside the storage chamber 53 between the first end face 55 and the second end face 57, and is fitted with the inner circumferential surface 58 of the storage chamber 53.

[0160] There is a small gap between the inner circumferential surface 58 of the receiving chamber 53 and the outer circumferential surface 74a of the bearing 74. Therefore, when an axial load is applied to the bearing 74, the bearing 74 can make a small displacement relative to the inner circumferential surface 58 of the receiving chamber 53 along the axial direction of the steering shaft 26.

[0161] Furthermore, the bearing 74 can be constructed from a "rolling bearing" such as a ball bearing or a roller bearing. A pair of annular support portions 75, 75 are located on both sides of the outer ring 74b of the bearing 74. The pair of support portions 75, 75 face each other axially across the bearing 74. Thus, inside the housing 53, the bearing 74 and the pair of support portions 75, 75 are located between the first surface 55 and the second end surface 57.

[0162] The outer ring 74b of the bearing 74 is supported all circumference by a pair of annular supports 75, 75 to be elastic in the axial direction of the steering shaft 26, in other words, to be floating supported.

[0163] As a result, the nut 73 is indirectly and elastically supported in the axial direction of the steering shaft 26 via the bearing 74.

[0164] The support portion 75 is provided in pairs, but in the following description, one of them will be used as an example.

[0165] The support portion 75 is composed of an annular elastic body 80 and an annular collar 90 supporting the elastic body 80. The elastic body 80 and the collar 90 are integrated together in the axial direction of the steering shaft 26.

[0166] The elastomer 80 is a ring-shaped component made of an elastic material that supports the outer ring 74b of the bearing 74 axially around the entire circumference of the steering shaft 26. Examples of elastic materials constituting the elastomer 80 include rubber monomers, resin monomers, combinations of rubber and resin, and two-color molded products of rubber and resin.

[0167] The collar 90 is made of metal and hard resin materials and is located between the elastomer 80 and the housing 50 in the axial direction of the steering shaft 26. The movement of the collar 90 along the axial direction of the steering shaft 26 is recorded by the housing 50.

[0168] As previously explained, the nut 73, a structural element of the ball screw 70, which is a rotary direct-drive conversion mechanism, is indirectly and elastically supported in the axial direction of the steering shaft 26 via a bearing 74. The bearing 74 is supported in the axial direction of the steering shaft 26 by a support portion 75 having an elastic body 80 and a collar 90. Furthermore, the collar 90 is located between the elastic body 80 and the housing 50 in the axial direction of the steering shaft 26.

[0169] Therefore, in other words, the elastic body 80 can be referred to as "a component disposed between the rotary direct conversion mechanism 26 and the housing 50, which elastically supports the rotary direct conversion mechanism 26 to the housing 50".

[0170] Next, refer to Figure 4 . Figure 4 It is a characteristic diagram that shows the relationship between the compressive load and the amount of compression of an elastomer.

[0171] exist Figure 4 In the example, the elastomer 80 has a first load characteristic and a second load characteristic.

[0172] The first load characteristic is the ratio of compressive load per unit compression along the axial deformation of the steering shaft 26, i.e., the characteristic of a gradual increase in spring stiffness. The second load characteristic is the ratio of compressive load per unit compression, i.e., the characteristic of a sharp increase in spring stiffness compared to the first load characteristic.

[0173] Figure 4 With the vertical axis set as the compressive load fc input to the elastic body 80 and the horizontal axis set as the compression amount δ of the elastic body 80, the characteristics of the compression amount δ of the elastic body 80 relative to the compressive load fc, i.e., the load characteristics, are shown.

[0174] exist Figure 4 In this context, the compressive load corresponding to the reference compression amount δa is the reference compressive load fca.

[0175] The range A1 of compression from the origin to the preset baseline compression amount δa is called the first range A1. The range A2 of compression from the baseline compression amount δa to the upper limit compression amount δb, which is half the length of the first range A1, is called the second range A2.

[0176] The first range A1 represents the range of the first load characteristic, and the second range A2 represents the range of the second load characteristic.

[0177] First, it is stated that "the deformation of the elastic bodies 80, 80 generated during the application of the driving force for abnormal detection to the movable part 26 is preferably the maximum elastic deformation that each of the elastic bodies 80, 80 can deform," and the compression amount corresponding to this "maximum elastic deformation that can deform" is equivalent to Figure 6 The maximum compression amount δb.

[0178] The displacement corresponding to the maximum elastic deformation that the elastomer 80, 80 can deform can be uniquely specified during the design phase. Therefore, it is possible to uniquely specify the minute displacement under normal conditions in advance.

[0179] In addition, the driving force used for anomaly detection can be described as "a driving force that, although unable to make the movable part 26 overcome the frictional force acting on the movable part 26 as a steering axis, can make the elastic body 80 produce the maximum deformation δb".

[0180] In a preferred embodiment, the driving force for anomaly detection can be described as "a driving force greater than the minimum driving force that can cause the movable part 26 to move despite not being able to overcome the frictional force acting on the movable part 26 as a steering axis."

[0181] Furthermore, considering the reduction of false positives, the driving force for anomaly detection is more preferably "a driving force that is large enough compared to the minimum driving force that can cause the movable part 26 to move against the frictional force acting on the movable part 26 as a steering axis, although it is not large enough to cause the movable part 26 to move against the frictional force acting on the movable part 26 as a steering axis".

[0182] Furthermore, if the driving force for abnormality detection is uniquely specified based on the characteristics of the aforementioned elastomer 80, then the typical amount of deformation, i.e., the typical amount of expansion and contraction, that can be conceived in the driving medium 63 such as the belt that is conceived to deform relative to the specified driving force shall be specified.

[0183] Therefore, as Figure 1As in the example provided with a drive medium 63 and an elastic body 80, "the total deformation of the drive medium 63 and the elastic body 80, which are temporarily deformable and are assumed to be deformable, during the application of a driving force for abnormal detection to the movable part 26, which serves as a steering shaft," is "the total deformation of the drive medium 63 as a belt, which is assumed to be deformable, in addition to the maximum elastic deformation δb that can be deformed in the elastic body 80, plus the total deformation of the drive medium 63 as a belt, which is assumed to be normally deformable, when the driving force for abnormal detection is applied," and can be uniquely specified during the design phase. Therefore, an appropriate threshold for abnormal detection can be set.

[0184] Next, refer to Figure 5 It is a cross-sectional view showing an example of a transmission mechanism using a worm and a worm wheel, which has components capable of elastic deformation.

[0185] As explained earlier Figure 1 , Figure 3 In the example, a ball screw is used as the mechanism for transmitting driving force, but... Figure 5 In the example, a transmission mechanism utilizing a worm gear and worm wheel is used as the transmission mechanism. Furthermore, in... Figure 5 In the example, as a rotary-to-linear conversion mechanism, it is assumed that a rack and pinion is used.

[0186] Figure 5 The transmission mechanism includes a motor body 24, a motor output shaft 25, a housing 113, a worm gear 610, a worm 620, a shaft 622, a first bearing 630, a second bearing 640, an elastic body 700A made of rubber or the like constituting the first worm damper, an elastic body 700B constituting the second worm damper, and a joint 650 that transmits the rotation of the motor output shaft 25 to the shaft 622 and the worm 620.

[0187] The connector 650 has an elastic component, namely a bushing 653, made of rubber or the like.

[0188] exist Figure 5 In the example, the worm 620 is connected to the output shaft 25 of the motor via a connector 650. The bushing 653 of the connector 650, the first elastic body 700A or the second elastic body 70A elastically deforms in the axial direction of the shaft portion 622, thereby enabling the worm 620 to move slightly in the axial direction.

[0189] In addition, since the worm gear 610 meshes with the worm 620, the elastic deformation of the bushing 653, the first elastic body 700A or the second elastic body 70A of the connector 650 in the axial direction of the shaft 622 will indirectly cause the worm gear 610 to also be slightly displaced in the axial direction of the shaft 622.

[0190] Here, for example, imagine the previous Figure 1The diagram shows a configuration where the pinion 509 engages with the output shaft 611 of the worm gear 610. In this configuration, if the worm gear 610 rotates, then... Figure 1 The pinion 509 shown rotates, and the movable part 26, which serves as the steering shaft, moves along... Figure 5 The example shows the axial movement of shaft 622.

[0191] In this case, the movable component 26, which serves as the steering shaft, can be indirectly and elastically supported on the housing 113 via the worm gear 610, worm 620, elastic bodies 700A, 700B, first bearing 630, or second bearing 640.

[0192] Here, Figure 5 The elastomers 700A and 700B in the text are equivalent to Figure 2 The components of the ball screw with elastic elements 80 and 80, in addition... Figure 5 The bushing 653, which is an elastic component, is equivalent to Figure 2 The transmission mechanism 44 in the ball screw is a component of the drive medium 63 that is capable of elastic deformation.

[0193] Figure 5 The elastomers 700A and 700B in the examples can also be referred to as "set in". Figure 1 The rotary-to-linear conversion mechanism 26 shown is a component that elastically supports the rotary-to-linear conversion mechanism 26 to the housing 113.

[0194] Therefore, as Figure 5 As shown, the present invention can also be applied in the example where a worm 620 and a worm wheel 610 are used as the transmission mechanism and a rack and pinion are used as the rotary-to-linear conversion mechanism.

[0195] Next, refer to Figure 6 . Figure 6 This is a characteristic graph showing an example of the displacement of the motor rotation angle relative to time under normal conditions during self-diagnostic processing.

[0196] exist Figure 6 In the middle, to and Figure 1 , Figure 3 The same reference numerals are used to label the same parts. However, in Figure 6 For ease of explanation, the main parts of the rotary-to-linear conversion mechanism are simplified and the description of the transmission components is omitted.

[0197] like Figure 6 As shown in A-1, the movable part 26, which is the steering shaft, is indirectly elastically supported on the housing 50, 50 via the nut 73 and bearing 74 of the ball screw 70, which is the rotary direct-acting conversion mechanism, and through the elastic bodies 80, 80.

[0198] exist Figure 6 In A-1, no rust or ice formed on the movable part 26. Furthermore, there were no obstacles such as curbs near the steering wheel 31, which is connected to the movable part 26 via the steering knuckle arm 29. Therefore, in a normal state, the movable part 26 can make normal, small displacements along the first and second directions DR1 and DR2 when an abnormality detection driving force is applied.

[0199] exist Figure 6 A-2 shows an example of the variation of the rotation angle of motor 5 with respect to time during anomaly detection. Furthermore, in the following description, the rotation angle of motor 5 is sometimes referred to as the "motor rotation angle".

[0200] exist Figure 6 In A-2, the period from time t1 to t5 is the self-diagnosis period for anomaly detection, during which the driving force for anomaly detection is applied to the movable part 26, which serves as the steering shaft.

[0201] As previously explained, in one of the preferred embodiments, the driving force for anomaly detection is a driving force capable of producing "the total deformation obtained by adding the maximum elastic deformation that can be deformed in the elastomers 80, 80 to the normal deformation that can be conceived of the belt 63 as the driving medium when the driving force for anomaly detection is generated".

[0202] The motor rotation angle "+Rn" is the rotation angle of the motor 5 corresponding to the displacement amount obtained by "the elongation of the belt 63, which serves as the driving medium of the transmission component 44, plus the displacement of the elastic body 80" in the first direction DR1.

[0203] The motor rotation angle "-Rn" is the rotation angle of the motor 5 corresponding to the displacement amount obtained by adding the elongation of the belt 63, which serves as the driving medium, of the transmission component 44 on the second direction DR2 to the displacement of the elastic body 80.

[0204] "+Rth" is the first threshold for anomaly detection in the first direction DR1. This first threshold "+Rth" can also be the same value as "+Rn", but in a preferred embodiment, to reduce false detections, it is set to "the value of the rotation angle corresponding to the elongation of the belt 63, which serves as the driving medium, in the first direction DR1 of the transmission member 44, i.e.,..." Figure 7 The value of "+Rs" in A-2 that is larger than "+Rn".

[0205] "-Rth" is the first threshold for anomaly detection in the second direction DR2. This second threshold "-Rth" can also be the same value as "-Rn", but in a preferred embodiment, it is set to a value greater than the rotation angle corresponding to the elongation of the belt 63, which serves as the driving medium, in the second direction DR2 of the transmission member 44. Figure 7The value of "-Rs" in A-2 is smaller than that of "-Rn".

[0206] exist Figure 6 In A-2, the area depicted by the diagonal line represents the range of variation of the motor rotation angle.

[0207] exist Figure 6 In A-2, the variation in the motor rotation angle during self-diagnosis exceeds the first threshold "+Rth" in the first direction DR1 and is below the second threshold "-Rth" in the second direction DR2.

[0208] therefore, Figure 1 The anomaly determination unit 411 in the anomaly detection unit 409 shown determines it as "normal".

[0209] Next, refer to Figure 7 This is a characteristic graph illustrating an example of the displacement of the motor rotation angle relative to time in the event of an anomaly during self-diagnostic processing. Figure 7 In the middle, to and Figure 6 The same parts are labeled with the same reference numerals.

[0210] exist Figure 7 In A-1, there are obstructions such as rust and ice between the nut 73 in the rotary direct-drive conversion mechanism, i.e., the ball screw 70, and the movable part 26, which serves as the steering shaft. Therefore, the movable part 26 is in an abnormal state where its normal movement is obstructed.

[0211] Due to this anomaly, nut 73 cannot move axially in the movable part 26, which serves as the steering shaft, and thus the elongation, or in other words, the "micro-displacement," of the elastomers 80, 80 is zero.

[0212] Therefore, the only detectable "micro-displacement" is the micro-displacement of the belt 63, which serves as the driving medium for the transmission component 44.

[0213] like Figure 7 As shown in A-2, the variation in the first direction DR1 of the motor rotation angle during self-diagnosis is only a variation corresponding to the motor rotation angle "+Rs", which corresponds to the elongation of the belt 63 of the transmission component 44, which serves as the driving medium, in the first direction DR1. That is, the detected motor rotation angle is lower than the first threshold "+Rs" in the first direction DR1.

[0214] Similarly, the change in motor rotation angle in the second direction DR2 during self-diagnosis is only a change corresponding to the motor rotation angle "-Rs", which corresponds to the elongation of the belt 63 of the transmission component 44, which serves as the driving medium, in the first direction DR2. That is, the detected motor rotation angle exceeds the second threshold "-Rth" in the second direction DR2.

[0215] therefore, Figure 1 The anomaly determination unit 411 in the anomaly detection unit 409 shown determines it as "abnormal".

[0216] Next, refer to Figure 8 . Figure 8 The figure shows a comparison between the motor rotation angle and the time required for anomaly detection in the self-diagnostic process of one embodiment of the present invention and a conventional example.

[0217] in addition, Figure 8 A-2 is to Figure 8 A magnified view of a portion of A-1. Figure 8 In A-2, the variation of the motor rotation angle in the present invention is shown in more detail.

[0218] exist Figure 8 In A-1, the characteristic line Q1 shown by the dashed line represents the range of variation of the motor rotation angle and the time required for anomaly detection when the movable part, which is the steering shaft, moves at its full stroke, i.e., the maximum stroke that can be moved, in order to perform anomaly detection.

[0219] Furthermore, the characteristic line Q2, represented by a very short solid line as a thick line, represents, in an embodiment of the present invention, the range of variation of the motor rotation angle and the time required for anomaly detection when a small driving force for anomaly detection is applied to the movable part, which is the steering shaft, during self-diagnosis and a temporary and reversible small displacement is generated.

[0220] In the existing example, for instance, when the movable part 26, which serves as a steering wheel, is moved in the first direction DR1, the motor rotation angle changes from "0" to "R20", with a change amount of "RB". Furthermore, the time required for anomaly detection is the period "TB" from time t10 to t20.

[0221] In contrast, in an embodiment of the present invention, the motor rotation angle changes from "0" to "R10", with a change amount of "RA". Additionally, the time required for anomaly detection is the period "TA" from time t10 to t11.

[0222] In addition, such as Figure 8 As shown in A-2, if the motor rotation angle in the embodiment of the present invention is shown more accurately, it shifts in the positive direction with "0" as the reference, and then shifts in the negative direction with "0" as the reference. That is, the motor rotation angle vibrates in both positive and negative directions.

[0223] In a preferred embodiment, the variation RA of the motor rotation angle in the present invention is less than 1 / 100 of the variation RB in conventional examples. Specifically, if the full stroke of the movable part, which serves as the steering shaft, is set to 100 mm, the normal small displacement of the movable part in the embodiment of the present invention is less than 1 mm, which significantly reduces the variation of the motor rotation angle compared to the conventional method.

[0224] Similarly, in a preferred embodiment, the time TA required for anomaly detection in the present invention is less than "1 / 100" of the time TB in conventional examples. Therefore, the time required for anomaly detection can be significantly reduced compared to the past.

[0225] <Example 2>

[0226] In this embodiment, an example of determining the situation where there are obstacles such as curbs near the steering wheels will be described.

[0227] Reference Figure 9 . Figure 9 This diagram illustrates a case where obstacles such as curbs are present near the steering wheels, but the self-diagnostic process determines it to be normal. Figure 9 In the middle, to and Figure 6 The same reference numerals are used to label the same parts.

[0228] like Figure 9 As shown in A-1, a curb 90, which acts as an obstacle, is located near the steering wheel 31 at a distance LA. That is, since the curb 90 is separated from the steering wheel 31 by a distance LA, the movable part 26 of the steering wheel can make a small displacement within a distance LA.

[0229] exist Figure 9 In A-2, the area with diagonal lines represents the range of minute displacements of the movable part 26.

[0230] As previously explained, "+Rs" and "-Rs" are motor rotation angles corresponding to the elongation of the belt 63, which serves as the driving medium of the transmission component 44, in the first and second directions DR1 and DR2, respectively.

[0231] In addition, the motor rotation angles “+Rn” and “-Rn” are the rotation angles of the motor 5 corresponding to the displacement amount obtained by “the elongation of the belt 63, which serves as the driving medium of the transmission component 44, plus the displacement of the elastic body 80” in the first and second directions DR1 and DR2.

[0232] like Figure 9As shown in A-2, during the self-diagnosis period, when the maximum displacement of the motor rotation angle reaches the values ​​of "+Rn" and "-Rn" of the motor rotation angle, and the abnormality is judged using the first and second thresholds "+Rth" and "-Rth", it is judged as "normal".

[0233] Next, refer to Figure 10 . Figure 10 This diagram illustrates an example of the judgment process when an obstacle such as a curb that contacts the steering wheel is detected during the self-diagnostic process. Figure 10 In the middle, to and Figure 9 The same reference numerals are used to label the same parts.

[0234] exist Figure 10 In section A-1, there is a curb 90 that acts as an obstacle and comes into contact with the steering wheel 31. Figure 9 Unlike example A-1, there is no gap between the steering wheel 31 and the curb 90. Therefore, the small displacement of the steering wheel 31 is hindered by the curb 90. As a result, there is no small displacement of the movable part 26, which serves as the steering axis, in the first direction DR1.

[0235] However, although the displacement of the movable part 26 is zero, due to the friction between the movable part 26 and the nut 73, the elastic body 80 located on the second direction DR2 side relative to the bearing 74 will contract, and the bearing 74 and the nut 73 will have a slight displacement towards the second direction DR2 side.

[0236] The minute displacement caused by the contraction of the elastic body 80 is the largest deformation within the range that the elastic body 80 can deform. This minute displacement is denoted as "W", and the corresponding motor rotation angle is denoted as "RW". Regarding this motor rotation angle RW, in... Figure 10 This will be explained in section A-4.

[0237] Since the displacement of movable part 26 is zero, therefore in Figure 10 In A-2, the motor rotation angle observed during self-diagnosis is only the motor rotation angle "+Rs" corresponding to the elongation of the belt 63, which serves as the driving medium, in the first direction DR1 of the transmission component 44.

[0238] In this case, the motor rotation angle is lower than the first threshold "+Rth", which is considered an "abnormal" situation.

[0239] However, this situation is different from the previous reference. Figure 7 The condition described in A-2, which involves rust, ice, or other obstacles to movement (Abn), cannot be distinguished.

[0240] In other words, it is impossible to distinguish whether it is... Figure 7Like the A-1, there are obstacles to movement such as rust and ice on Abn, or is it like... Figure 10 There are obstacles such as curbs 10 that come into contact with the steering wheel 31.

[0241] If it is like this Figure 10 If there are obstacles such as curbs 10 as in A-1, then as long as the vehicle 10 is moved to release the steering wheel 31 from the contact with the obstacles such as curbs 10, the movable part 26 can make a small displacement in the first direction DR1, and as a result of self-diagnosis, it will be judged as "normal".

[0242] In other words, although in Figure 10 The condition of A-1 can be described as follows: "Although there are no obstructions such as rust or ice on Abn, which is normal, the presence of obstacles such as curbs makes it appear abnormal." This is in contrast to... Figure 7 The situation shown in A-1, "an abnormal situation has occurred where there are obstacles to movement such as rust and ice Abn", is clearly different.

[0243] Therefore, in self-diagnosis, it is preferable to... Figure 10 The condition of A-1 is detected, and countermeasures are taken in case there are obstacles 10 such as curbs, such as notifying the occupants of vehicle 10, including the driver.

[0244] In order to Figure 7 To distinguish the condition of A-1 for detection Figure 10 The situation of A-1, in Figure 10 In A-3, the driving force for abnormal detection is increased, causing the movable part 26 to be displaced in the second direction DR2.

[0245] Here, in the case where there is an obstacle such as a curb 90 that is in contact with the steering wheel 31 located on the first direction DR1 side relative to the movable part 26, there is usually no obstacle such as a curb at the steering wheel located on the second direction DR2 side, which is the opposite direction.

[0246] In other words, it can be envisioned that in the second direction DR2, there are no obstacles such as curbs that would impede the slight displacement of the movable part 26.

[0247] Therefore, when an abnormality detection driving force is applied to the movable part 26, the movable part 26 will produce a slight displacement in the second direction DR2. In addition, the bearing 74 and the nut 73 will also produce a slight displacement in the first direction DR1 due to the friction between the movable part 26 and the nut 73.

[0248] Here, pay attention Figure 10 The elongation and contraction of a pair of elastomers 80, 80 in A-3. Furthermore, as previously explained, in Figure 10 In A-1, the elastic body 80 produces the largest deformation within its deformable range, and this deformation is accompanied by a displacement "W" in the elastic body 80.

[0249] exist Figure 10 In A-3, Figure 10 In A-1, the contracted elastomer 80 elongates by displacement "W", first recovers to the neutral position where the displacement is zero, and then elongates from the neutral position according to displacement "W" to become an elongated state.

[0250] On the other hand, Figure 10 The elongated elastic body 80 in A-1 contracts according to the displacement "W", and after returning to the neutral position where the displacement is zero, it contracts from the neutral position according to the displacement "W" to become a contracted state.

[0251] That is, in Figure 10 In A-3, the elastomer 80 produces a small displacement of "2W".

[0252] Here, Figure 10 The driving force used for anomaly detection in A-1 is a driving force that generates "the displacement "W" of the elastic body 80 plus the small displacement obtained by the elongation displacement of the belt 63, which serves as the driving medium, in the transmission component 44".

[0253] On the other hand, Figure 10 In A-3, the driving force for abnormal detection is increased and set to generate a small displacement by adding the displacement of the elastic body 80 displacement "2W" plus the displacement of the belt 63, which is the driving medium of the transmission component 44.

[0254] Therefore, in Figure 10 In A-3, the following variation in motor rotation angle occurs, which corresponds to the "small displacement obtained by the displacement of the elastic body 80 "2W" plus the displacement of the belt 63, which serves as the driving medium, in the transmission component 44".

[0255] Focus on Figure 10 The latter half of the self-diagnosis period in A-4, i.e., the period from time t3 to t5.

[0256] During this period, a driving force is applied to the movable part 26 to produce a small displacement in the second direction DR2. In this case, the change in the motor rotation angle is the following change: the motor rotation angle "Rs" corresponding to the extension of the belt 63 plus the motor rotation angle "RW" corresponding to the displacement W until it returns to the neutral position, and the motor rotation angle "RW" corresponding to the displacement W from the neutral position to the maximum displacement position.

[0257] exist Figure 10In A-4, during the period from time t3 to t4, "-Rth2" is used as the threshold for anomaly detection. Here, if we ignore the sign and compare the absolute values, then "Rth2 > Rth". Since this increases the driving force for anomaly detection, correspondingly, the threshold with the larger absolute value, Rth2, is used as the threshold for anomaly detection. If we consider the sign, it can also be said that the threshold "-Rth2" is used to determine whether there is an anomaly.

[0258] exist Figure 10 In A-4, during the period from time t3 to t4, the maximum variation of the range of the motor rotation angle, that is, the range of the area marked by the diagonal line and sand pattern in the figure, is lower than the threshold "-Rth2". Therefore, it is determined that the movable part 26 in the second direction DR2 has produced a normal small displacement.

[0259] exist Figure 10 In the example, the situation is as follows: an anomaly is detected in the first direction DR1, but no anomaly is detected during the anomaly detection process performed in the second direction DR2 by increasing the driving force. Therefore, in this case, it can be determined that there is an obstacle such as a curb obstructing the displacement of the steering wheels in the first direction DR1. Furthermore, the details of the processing steps for detecting the presence of obstacles such as curbs will be described later.

[0260] <Example 3>

[0261] In this embodiment, the processing steps in the self-diagnostic process for anomaly detection are described as an example.

[0262] Reference Figure 11 . Figure 11 This is a flowchart illustrating an example of the overall processing steps for self-diagnostic procedures.

[0263] In step S1, the steering control device 500 determines whether self-diagnosis can be performed. For example, if it confirms that at least one of the following is true: the ignition switch or other starter switch is off, the parking brake is on, the vehicle speed of 10 is zero, or the input of steering commands from occupants, including the driver, to the motor control unit 403 is cut off, it determines that it is in a state where self-diagnosis can be performed.

[0264] If the answer in step S1 is "yes", proceed to step S2; if the answer is "no", repeat step S1.

[0265] In step S2, it is determined whether the self-diagnostic process has started. If it is "yes", proceed to step S3; if it is "no", return to step S1.

[0266] In step S3, the steering control device 500 activates the trigger signal required for self-diagnosis processing and the signal indicating the specified conditions, thus satisfying the conditions for starting self-diagnosis.

[0267] Specifically, for example, when the ignition switch is on, a start signal as a trigger signal is input to the motor control unit 403, or when an occupant, including the driver, turns on the self-diagnostic start switch, a self-diagnostic start signal as a trigger signal is input to the motor control unit 403.

[0268] In step S4, a self-diagnostic process is performed.

[0269] In step S5, it is determined whether there is no abnormality. If the result is "no", that is, there is an abnormality, proceed to step S6; if the result is "yes", that is, there is no abnormality, proceed to step S7.

[0270] In step S6, abnormality countermeasures are implemented. For example, abnormality notification and partial restriction of vehicle movement are implemented. After that, the process proceeds to step S7.

[0271] In step S7, the self-diagnosis termination process is implemented. For example, the following process is implemented: the actions and measures that were restricted due to the self-diagnosis being performed are restored to an unrestricted state.

[0272] Next, refer to Figure 12 . Figure 12 This is a flowchart illustrating an example of the processing steps for determining whether a self-diagnostic process can be implemented. That is, Figure 12 Show Figure 11 The specific steps of step S1 shown are illustrated in the example.

[0273] In step S11, it is determined whether self-diagnosis processing can be performed.

[0274] In step S12, it is determined whether a vehicle stopping measure has been performed while the vehicle is parked. If the result is "no", the process returns to step S11; if the result is "yes", the process proceeds to step S13.

[0275] In step S13, the steering command input from the steering wheel is invalidated.

[0276] In step S14, it is confirmed whether the steering command input from the steering wheel has been invalidated. In this invention, very small displacements need to be detected. When the steering command input is valid, this small displacement cannot be detected; therefore, in step S14, as a precaution, it is confirmed that the steering command input has been invalidated. If the result in step S14 is "No," the process returns to step S13; if the result is "Yes," the process proceeds to step S15.

[0277] In step S15, self-diagnostic processing is enabled.

[0278] Next, refer to Figure 13 . Figure 13 This is a flowchart illustrating an example of the specific processing steps for self-diagnosis. That is, Figure 13 express Figure 11 This is an example of the specific steps involved in step S4.

[0279] In step S10, the steering control device provides a drive command for abnormality detection to the motor.

[0280] In step S20, a driving force for abnormality detection is applied to the movable part.

[0281] In step S30, a temporary and reversible small displacement caused by the deformation of the elastomer is measured.

[0282] In step S40, the measured values ​​of the physical quantities corresponding to the minute displacements are obtained.

[0283] In step S50, for the measured stroke amount and the normal stroke amount, it is determined whether the relationship between the measured stroke amount and the normal stroke amount holds. If it is "yes", proceed to step S60; if it is "no", proceed to step S80.

[0284] In step S60, an anomaly is determined, and then in step S70, anomaly countermeasures are executed. For example, an anomaly notification is issued, or measures are taken to restrict part of the vehicle's movement.

[0285] In step S80, if no abnormality is found, the self-diagnosis process ends.

[0286] Next, refer to Figure 14 . Figure 14 This is another flowchart illustrating the specific processing steps of a self-diagnostic procedure. That is, Figure 14 It shows in Figure 11 The execution of step S4 in the self-diagnosis process includes an application example of the processing steps for detecting and processing obstacles such as curbs.

[0287] In addition, Figure 14 For ease of explanation, the previously shown "first direction DR1" is defined as the left side when observed by occupants, including the driver, and is referred to as "left" or "left side". Similarly, the previously shown "second direction DR2" is defined as the right side when observed by occupants, including the driver, and is referred to as "right" or "right side".

[0288] exist Figure 14In the processing steps, in the self-diagnostic processing for abnormality detection, driving force is applied to the movable part 26, which is the steering shaft, in each left and right direction and the minute displacement in each direction is detected. Based on the measured value of the minute displacement in each direction, it is determined whether there is an abnormality and whether there are obstacles such as curbs.

[0289] In other words, in Figure 14 In the example, the following two situations can be distinguished for detection: the two situations are: anomalies caused by rust, ice, etc., which restrict the movement of movable parts; and a situation where, although no such anomaly occurs, the slight displacement of the steering wheel is hindered by obstacles such as curbs.

[0290] In addition, Figure 14 In the example, it is also possible to determine whether the deviation of the stroke value caused by friction in the left and right directions of the movable part 26 (hereinafter referred to as friction deviation) is too large, and to detect any abnormalities based on the result. In this case, more careful and reliable abnormality detection can be performed.

[0291] The following is an explanation in order.

[0292] In step S100, it is determined whether the left side is in a state of no abnormality. That is, an abnormality detection driving force is applied to the movable part 26, the measured value of the resulting minute displacement is obtained, and compared with a pre-prepared predetermined threshold. For example, if the measured value as an absolute value is above the threshold as an absolute value, it is determined to be in a state of no abnormality, i.e., normal.

[0293] If the answer in step S100 is "yes", then proceed to step S101; if the answer is "no", then proceed to step S200. Step S200 and subsequent steps will be described later.

[0294] In step S101, the same method is used to determine whether the right-hand side is in a state of no abnormality. If the result in step S101 is "no", proceed to step S301. Step S301 and subsequent steps will be described later.

[0295] When "yes" is selected in step S101, that is, when the right side is also determined to be without abnormality, it is generally considered that no abnormality was detected in this self-diagnosis, and the process moves to step S103, where the self-diagnosis can be terminated.

[0296] In other words, if there are no abnormalities in the left and right directions, it can be determined as normal.

[0297] However, in Figure 14 In the example of the processing steps, to be more cautious and to reduce false judgments, the judgment in step S102 can also be performed before the processing in step S103.

[0298] When performing step S102, it is determined whether the friction deviation estimated based on the small displacements in the left and right directions, i.e., the left and right friction force deviation, is within a predetermined allowable range, or in other words, whether it is within the normal range, i.e., whether it is not excessively large beyond the normal range.

[0299] That is, after the determination in steps S100 and S200, it is tentatively determined that there is no abnormality in the left and right directions. However, there is a difference between the stroke amount of the first micro displacement on the left and the stroke amount of the second micro displacement on the right. Moreover, if the difference in the stroke amount exceeds the preset allowable range or the normal range, that is, if the friction deviation exceeds the normal range and is too large, it can be estimated that there is a high probability that the movement is constrained due to the influence of rust, ice, etc. in at least one direction of the movable part that serves as the steering shaft, although the constraint may be slight.

[0300] Therefore, if the result in step 102 is "No", as a precaution, an exception is determined to have occurred, and the process proceeds to step S308. Step S308 and subsequent processing will be explained later.

[0301] Next, the processing steps S200 to S204 will be explained. Furthermore, the series of processes in steps S201 to S204 show the process for re-diagnosis when both the left and right directions are determined to be abnormal; in other words, an example of the re-diagnosis process after the first determination of an abnormality is shown.

[0302] Even if the left and right directions are deemed abnormal in the first determination, there is still a possibility of false determination because the displacement detected in this invention is a very small displacement.

[0303] Additionally, as previously mentioned Figure 10 As explained in A-1, it is conceivable that although there is no actual abnormality caused by rust, ice, etc., the presence of obstacles such as curbs that come into contact with the steering wheels may appear to be abnormal.

[0304] Therefore, in Figure 14 In the example of the processing steps, as a precaution, a re-diagnosis is performed in steps S201 to S204 to reduce the possibility of misjudgment.

[0305] In step S200, similar to step S101 described above, it is determined whether the right side is in a state of no abnormality.

[0306] If "Yes" is selected in step S200, proceed to step S301. Step S301 and its subsequent processing will be described later.

[0307] If the result in step S200 is "No", proceed to step S201. As explained earlier, in the first determination, even if both the left and right directions are determined to be abnormal, there is still a possibility of misdetermination. Therefore, to be on the safe side, a re-diagnosis process should be performed, in other words, a retry process should be performed.

[0308] In step S201, in order to ensure its effectiveness, the driving force for abnormality determination is increased compared with the first determination in steps S100 and S200, and the diagnosis process is started again.

[0309] Furthermore, multiple re-diagnoses can be performed, but in this case, it is preferable to increase the driving force for abnormality detection sequentially in each re-diagnosis to improve the effectiveness of the re-diagnosis.

[0310] Furthermore, the extent to which the driving force should be increased can be predetermined during the design phase from the perspective of suppressing misjudgments. For example, as previously stated... Figure 10 As explained in A-3, the presence or absence of curb stones, etc., can be detected by applying a driving force to the movable part 26 that produces a displacement that is twice the displacement of the elastic body 80 plus the displacement caused by the elongation of the belt 63, etc. of the transmission part 44.

[0311] With this in mind, for example, in the first determination, i.e., steps S100 and S200, a driving force can be applied to the movable member 26 to produce a displacement that is "the displacement of the elastic body 80 plus the displacement caused by the elongation of the belt 63 of the transmission member 44, etc." On the other hand, regarding the re-diagnosis, i.e. steps S201 to S204, an increased driving force can be applied to the movable member 26 to produce a displacement that is "twice the displacement of the elastic body plus the displacement caused by the elongation of the belt 63 of the transmission member 44, etc."

[0312] In step S202, it is determined whether there is no abnormality on the left. That is, an increased driving force for abnormality detection is applied to the movable part, the measured value of the small displacement resulting therefrom is obtained, and it is compared with a pre-prepared threshold corresponding to the increased driving force.

[0313] For example, if the measured value as an absolute value is above the threshold as an absolute value, it is judged as having no abnormality, that is, normal.

[0314] If the answer in step S202 is "yes", then proceed to step S203; if the answer is "no", then proceed to step S204.

[0315] In step S203, for the right side, it is determined in the same way whether it is in an abnormal state.

[0316] If "yes" is selected in step S203, the diagnosis is repeated, i.e., a retry is performed, and it is determined that there are no abnormalities in the left and right directions.

[0317] Therefore, in this case, it is judged to be normal, and then the process proceeds to step S103 to implement the self-diagnosis termination process.

[0318] If "No" is selected in step S203, during the re-diagnosis performed by increasing the driving force, it is determined that there is no abnormality on the left but there is an abnormality on the right.

[0319] In this situation, there is a higher probability that there are obstacles such as curbs that come into contact with the steering wheels on the right. Therefore, in principle, the process proceeds to step S306. In step S306, obstacles such as curbs are detected.

[0320] In addition, the statement "in principle, the process is transferred to step S306" is because, similar to step S102, out of caution, it is possible to first determine in step S305 whether the left and right frictional force deviation is within the allowable range.

[0321] If step S305 is performed and the condition is "No" in step S305, it is highly likely that a constraint causing movement due to rust, icing, or other factors will occur in at least one left or right direction of the movable part that serves as the steering shaft, even if the constraint is minor. Therefore, as a precaution, it is determined that there is an anomaly, and the process proceeds to step S308.

[0322] Additionally, if "yes" is indicated in step S305, the process proceeds to step S306, where obstacles such as curbs are detected.

[0323] In step S307, for example, a process is performed to notify occupants, including the driver, that an obstacle such as a curb has been detected. Then, the process proceeds to step S103, where a self-diagnostic termination process is performed.

[0324] Additionally, in step S204, it is determined whether there is no abnormality on the right side. If the result in step S204 is "No," then during the re-diagnosis performed by increasing the driving force, it is determined that there is an abnormality in both the left and right directions. In this case, the process proceeds to step 308.

[0325] In this case, in step 308, an anomaly is detected that hinders the displacement of the movable part due to rust, ice, or other factors.

[0326] Next, in step S309, abnormality countermeasures are implemented. For example, notifying occupants, including the driver, that an abnormality has occurred, or implementing measures to restrict the vehicle's movement, such as temporarily stopping the vehicle.

[0327] Additionally, when "yes" is set in step S204, during the re-diagnosis performed by increasing the driving force, the left side is determined to be abnormal, but the right side is determined to be normal.

[0328] In this situation, there is a higher probability that there is an obstacle such as a curb that is in contact with the steering wheel on the left. Therefore, in principle, the process proceeds to step S306. In step S306, the obstacle such as the curb is detected. However, as explained earlier, step S305 can also be performed before step S306.

[0329] Next, the processing steps S301 to S304 will be explained. This series of processes is related to the re-diagnosis when the result of the first determination shows that either the left or right side is normal but the other side is abnormal.

[0330] In this situation, for directions deemed abnormal, the presence of obstacles such as curbs can be identified. That is, an initial determination of the presence of curbs, etc., can be made, but there is also the possibility of false determinations. Therefore, in Figure 14 In the example of the processing steps, in order to reduce misjudgment and as a precaution, a second diagnosis is performed after the first judgment of curb stones, etc.

[0331] In step S301, in order to ensure its effectiveness, the driving force for abnormality determination is increased and the diagnostic process is started again compared with the first determination in steps S100 and S101.

[0332] Furthermore, multiple re-diagnoses can be performed, but in this case, it is preferable to increase the driving force for abnormality detection sequentially in each re-diagnosis to improve the effectiveness of the re-diagnosis.

[0333] Furthermore, the extent to which the driving force should be increased can be predetermined during the design phase from the viewpoint of suppressing false judgments. As an example, the method for increasing the driving force described in step S201 can be applied.

[0334] In step S302, it is determined whether there is no abnormality on the left. That is, an increased driving force for abnormality detection is applied to the movable part, and the measured value of the small displacement resulting therefrom is obtained and compared with a pre-prepared threshold corresponding to the increased driving force. For example, if the measured value as an absolute value is above the threshold as an absolute value, it is determined that there is no abnormality, that is, it is normal.

[0335] If the answer in step S302 is "yes", then proceed to step S303; if the answer is "no", then proceed to step S304.

[0336] In step S303, the same method is used to determine whether the right side is in a state of no abnormality.

[0337] When "yes" is selected in step S303, the diagnosis can be repeated, i.e., a retry, to determine that there are no abnormalities in either the left or right directions.

[0338] In other words, it is known that the problem is unrelated to obstacles such as curbs. Therefore, in principle, we proceed to step S103 to perform the self-diagnosis termination process. However, as previously explained, step S102 can also be performed before step S103.

[0339] If "No" is selected in step S303, during the re-diagnosis performed by increasing the driving force, it is determined that there is no abnormality on the left but an abnormality on the right. In this case, there is a high probability that there is an obstacle such as a curb that is in contact with the steering wheel on the right.

[0340] Therefore, in this case, the process proceeds to step S306 in principle. In step S306, obstacles such as curbs are detected. However, as previously explained, step S305 may also be performed before step S306.

[0341] Additionally, in step S304, it is determined whether there is no abnormality on the right side. If the result in step S304 is "No," then during the re-diagnosis performed by increasing the driving force, it is determined that there is an abnormality in both the left and right directions. In this case, the process proceeds to step 308.

[0342] In this case, in step 308, an anomaly is detected that hinders the movement of movable parts due to rust, ice, or other factors. Next, in step S309, anomaly countermeasures are implemented. For example, this may involve notifying occupants, including the driver, of the anomaly, or implementing measures to temporarily stop the vehicle, thus limiting its movement.

[0343] In addition, when "yes" is set in step S304, during the re-diagnosis performed by increasing the driving force, although the left side is determined to be abnormal, the right side is determined to be without abnormality.

[0344] In this situation, there is a higher probability that there is an obstacle such as a curb that is in contact with the steering wheel on the left. Therefore, in principle, the process proceeds to step S306. In step S306, an obstacle such as a curb is detected. However, as previously explained, step S305 may also be performed before step S306.

[0345] An example of the structure and effects of the embodiments of the present invention described above is as follows.

[0346] According to a first aspect of the steering device of the present invention, a steering device (700) is provided, which is installed in a vehicle to steer the steering wheels (31, 31) of the vehicle, wherein the steering device (700) comprises: a movable member (26) connected to the steering wheel and steer the steering wheel; a housing (50) covering at least a portion of the movable member and fixed to the vehicle body; a motor (5) applying a steering force to the movable member; a rotary-to-linear conversion mechanism (70) disposed within the housing, which converts the rotary motion transmitted from the motor into linear motion and transmits it to the movable member; and an elastic body (80, 80) provided with... The rotary direct-acting conversion mechanism is placed between the rotary direct-acting conversion mechanism and the housing, and the rotary direct-acting conversion mechanism is elastically supported in the housing; and the control device (500) responds to the condition that triggers the action confirmation or the condition that is set, by outputting a first control signal (SG20) to the motor, causing the rotary direct-acting conversion mechanism to move relative to the movable part more than the displacement corresponding to the elastic support amount of the elastic body, acquiring a physical quantity related to the movement amount of the movable part based on the first control signal, and judging whether there is an abnormality based on the physical quantity related to the movement amount of the movable part, and outputting an abnormality judgment signal (SG35) when an abnormality is judged.

[0347] According to the first method, instead of mechanically moving the movable parts constituting the steering shaft, etc., from a normal point of view, the focus is on the extremely small displacement caused by the deformation of the elastic body, and the abnormality is determined based on the small displacement.

[0348] By using an anomaly detection method that is fundamentally different from the past, the stroke of the moving parts required for anomaly detection and the time required for anomaly detection can be significantly reduced compared to the past.

[0349] In the second approach, which is subordinate to the first approach, the steering device may have either a first structure or a second structure. In the first structure, only an elastic body (80, 80) is provided as a structural element that undergoes temporary and reversible deformation during the period when a drive command for abnormality detection, which serves as a first control signal, is provided to the motor. In the second structure, in addition to the elastic body, a drive medium (63) conceived as deformable is provided in a transmission mechanism (44) disposed between the motor and the rotary-to-direction conversion mechanism, which transmits the driving force generated by the rotation of the motor to the rotary-to-direction conversion mechanism. The control device (500) has a motor control unit (403) for controlling the motor and an abnormality detection unit (409) for detecting abnormalities in the normal movement of the movable part. When an abnormality is detected, the motor control unit generates an abnormality detection signal by providing a drive command for abnormality detection, which serves as a first control signal, to the motor. The driving force is applied to the movable part for anomaly detection. Although the driving force for anomaly detection cannot make the movable part move by overcoming the friction acting on the movable part, it can cause the elastic body or the driving medium and the elastic body, which are assumed to be deformable, to deform. The anomaly detection unit measures the minute displacement of the movable part and obtains the measured value of the physical quantity corresponding to the minute displacement. The minute displacement corresponds to the total deformation of the temporary and reversible elastic body generated during the application of the driving force for anomaly detection to the movable part, or the deformation of the driving medium and the elastic body, which are assumed to be deformable. If the first stroke amount corresponding to the minute displacement shown in the measured value is smaller than the second stroke amount corresponding to the normal minute displacement generated under the condition of no anomaly, an anomaly is determined to be present.

[0350] According to the second method, instead of mechanically moving movable parts such as the rack constituting the steering shaft in the conventional sense, the focus is on the temporary, extremely small, reversible displacement caused by an elastic body or the like during the period when a driving force for abnormality detection is generated in the motor in response to a drive command for abnormality detection, and an abnormality is determined based on this small displacement. This small displacement can also be described as a swaying or rocking motion in the steering actuator; it is a temporary and recoverable displacement, fundamentally different from the conventional concept of mechanically moving movable parts. Therefore, according to the present invention, the stroke of the movable part required for abnormality detection can be reduced to, for example, less than 1 / 100 of the conventional amount, and the time required for abnormality detection can also be reduced to less than 1 / 100 of the conventional amount.

[0351] Furthermore, unlike existing examples, it does not require detecting abnormal phenomena such as a decrease in motor speed or periodic fluctuations in motor speed. For example, abnormalities can be easily identified through simplified threshold determination.

[0352] Furthermore, in the past, since moving movable parts and steering wheels required significant movement, the movement of steering wheels would be hindered by obstacles such as curbs around them, making accurate anomaly detection impossible. Therefore, as a prerequisite for anomaly detection, images of the area around the steering wheels must first be captured using a camera to detect the absence of obstacles. However, in this invention, since the steering wheels do not actually move, it is not necessary to detect obstacles based on such images, thus making anomaly detection easier.

[0353] In the third method, which is subordinate to the second method, the deformation of the elastic body generated during the period when the driving force for abnormal detection is applied to the movable part is the maximum elastic deformation that the elastic body can deform. Alternatively, the total deformation of the driving medium and the elastic body, which are assumed to deform temporarily generated during the period when the driving force for abnormal detection is applied to the movable part, is the total deformation obtained by adding the maximum elastic deformation that the elastic body can deform to the normal deformation that the driving medium can conceive when the driving force for abnormal detection is generated.

[0354] In the third approach, the driving force used for anomaly detection is either a driving force capable of causing the elastomer to produce the maximum elastic deformation that it can deform, or a driving force capable of producing a total deformation that is the sum of the maximum elastic deformation that the elastomer can deform and the conceivable normal deformation of the driving medium under the condition of generating the driving force for anomaly detection.

[0355] The maximum elastic deformation that the elastomer can deform, or the typical deformation that the driving medium can conceive of under the condition of generating the driving force for anomaly detection, can be uniquely specified during the design phase. Therefore, the driving force for anomaly detection can also be uniquely specified as an appropriate value.

[0356] In the fourth method, which is subordinate to the first or second method, the measured value of the physical quantity corresponding to the minute displacement may be at least one of the following: the detected value of the rotation angle of the motor, the detected value of the rotation angle of the pinion (509) meshing with the rack as a movable part, and the detected value obtained by detecting the displacement of the rack as a movable part by a non-contact sensor (511).

[0357] In the fourth approach, minute displacements can be accurately detected using the rotation angle of the motor that constitutes the steering device's actuator. Furthermore, minute displacements can also be accurately detected by using the rotation angle of the pinion meshing with the rack, which is a movable component. Additionally, minute displacements can also be accurately detected using, for example, the latest non-contact sensors such as optical displacement sensors. Therefore, the present invention can be applied in practice.

[0358] In a fifth embodiment belonging to at least one of the first to fourth embodiments, the anomaly detection unit may perform a threshold determination when an anomaly is determined. In the first embodiment, where only the elastic body deforms, and in the second embodiment, where the driving medium and the elastic body, which are both assumed to deform, deform separately, the threshold is set to a travel value smaller than the travel value of the movable part corresponding to the maximum elastic deformation that can be deformed. In the second embodiment, the threshold is set to a travel value larger than the travel value of the micro-displacement corresponding to the maximum elastic deformation that the elastic body can deform, and smaller than the travel value of the micro-displacement corresponding to the following total deformation, which is the total deformation obtained by adding the maximum elastic deformation that the elastic body can deform to the normal deformation that the driving medium can be assumed to have generated when the driving force for anomaly detection is generated.

[0359] According to the fifth method, a reliable anomaly determination can be implemented without increasing the burden on the anomaly detection unit by setting an appropriate threshold and comparing the measured value with the threshold.

[0360] In the sixth method, which is subordinate to the fifth method, the anomaly detection unit may variably control the threshold based on at least one of the vehicle's ambient temperature and the vehicle's driving history.

[0361] According to the sixth method, the threshold for anomaly determination is variably, in other words, adaptively controlled based on at least one of the vehicle's ambient temperature and the vehicle's driving history. Therefore, the threshold for anomaly detection can be appropriately fine-tuned according to the ambient temperature and usage history.

[0362] In the seventh method, which is subordinate to any of the first to sixth methods, the motor control unit and the abnormality detection unit may perform a self-diagnostic process to determine whether there is an abnormality when the vehicle is not in motion.

[0363] According to the seventh method, self-diagnosis can be performed in advance before the vehicle 10 enters a driving state, thus preventing accidents caused by abnormalities from occurring.

[0364] In the eighth method, which belongs to any of the first to sixth methods, the motor control unit and the abnormality detection unit may perform a self-diagnostic process to determine whether there is an abnormality when the vehicle is stopped with the vehicle's start switch turned on and there is no steering operation input from the vehicle's occupants.

[0365] According to the eighth method, for example, even during the idling stop of the vehicle in motion, it is possible to perform anomaly determination based on self-diagnosis in advance under the condition that there is no steering operation input, so as to prevent accidents and failures caused by the restriction of the movement of movable parts due to rust, ice, etc.

[0366] In the ninth embodiment, which belongs to any of the first to eighth embodiments, the movable part can be moved in a first direction and a second direction opposite to the first direction, respectively. The elastic body includes a first elastic body that can deform in the first direction by contraction deformation and a second elastic body that can deform in the second direction by contraction deformation. The motor control unit applies a driving force for abnormality detection to the movable part and performs a first action that deforms the first elastic body in the first direction and a second action that deforms the second elastic body in the second direction, respectively. If the abnormality detection unit detects an abnormality in either the first abnormality determination process corresponding to the first action or the second abnormality determination process corresponding to the second action, it determines that there is an abnormality.

[0367] According to the ninth method, abnormalities in the first and second directions are diagnosed separately. If both the first and second directions are determined to be abnormal, an abnormality is determined to exist. By comprehensively considering abnormalities in the first and second directions to perform abnormality determination, the possibility of false positives can be reduced.

[0368] In the tenth method, which is subordinate to the ninth method, if the control device detects an abnormality in either the first abnormality determination process or the second abnormality determination process, a first re-diagnosis is performed before determining that there is an abnormality. If the abnormality detection driving force applied to the movable part during the first or second abnormality determination process is set as the first driving force, in the first re-diagnosis, the motor control unit applies a second driving force greater than the first driving force to the movable part to re-perform the first and second abnormality determination processes. If an abnormality is detected in both the first and second abnormality determination processes in the first re-diagnosis, the abnormality detection unit determines that there is an abnormality. If an abnormality is detected only in either the first or second abnormality determination process in the first re-diagnosis, the abnormality detection unit determines that there is an obstacle in contact with a steering wheel, and implements countermeasures for the presence of an obstacle. The steering wheel is the steering wheel in the direction corresponding to the abnormality determination process in which the abnormality was detected. If no abnormality is detected in either the first or second abnormality determination process in the first re-diagnosis, the abnormality detection unit determines that everything is normal.

[0369] In the tenth method, similar to the ninth method, abnormalities in the first and second directions are diagnosed respectively. If both the first and second directions are determined to be abnormal, it is determined that there is an abnormality.

[0370] However, in this approach, out of caution and to further reduce the possibility of misdiagnosis, an abnormality is not immediately determined, but an additional first re-diagnosis is performed.

[0371] In the first re-diagnosis, the driving force used for anomaly detection is increased compared to the driving force used in the first determination. When the first re-diagnosis is performed with an increased driving force, and anomalies are determined in both the first and second directions as in the first determination, the probability of an actual anomaly is considered higher. Therefore, anomaly detection with higher reliability can be performed.

[0372] In addition, in the first and second diagnoses, if there are no abnormalities in the first and second directions, it can be determined as normal.

[0373] Furthermore, in the first re-diagnosis, as a result of the abnormality determination implemented by increasing the driving force, if either the first or second one is determined to be normal and the other one is determined to be abnormal, since either one is normal, it is more likely that there is no abnormality caused by rust, ice, etc. The reason for the other one being determined to be abnormal can be estimated to be other phenomena, such as the presence of obstacles such as curbs that come into contact with the steering wheel, or in other words, the vehicle's wheels.

[0374] Therefore, if the driving force is increased and the result of the first self-diagnosis is that an abnormality is only determined in either the first or second direction, it is determined that there is no abnormality caused by rust, ice, etc., but the displacement of the steering wheel is hindered by obstacles such as curbs, and appropriate countermeasures are taken, such as notifying the driver of the presence of curbs, etc.

[0375] In this way, by adding a first re-diagnosis, the original detection object, i.e., the abnormality caused by rust, ice, etc., can be clearly distinguished from the superficial abnormality caused by the presence of curb stones, etc., thus improving the accuracy of abnormality determination.

[0376] In the eleventh embodiment, which belongs to any of the first to eighth embodiments, the movable part may be able to move in a first direction and a second direction opposite to the first direction, respectively. The elastic body includes a first elastic body that can deform in the first direction by contraction deformation and a second elastic body that can deform in the second direction by contraction deformation. The motor control unit applies a driving force for abnormality detection to the movable part and performs a first action that deforms the first elastic body in the first direction and a second action that deforms the second elastic body in the second direction, respectively. If an abnormality is detected in either the first abnormality determination process corresponding to the first action or the second abnormality determination process corresponding to the second action, the abnormality detection unit performs a second re-diagnosis before determining that an abnormality has occurred. The abnormality detection driving force applied to the movable part during the first or second abnormality determination process is used to perform the abnormality detection. When the first driving force is set, in the second re-diagnosis, the motor control unit applies a third driving force greater than the first driving force to the movable part to re-implement the first abnormality determination process and the second abnormality determination process. In the second re-diagnosis, if an abnormality is detected in either the first or second abnormality determination process, the abnormality detection unit determines that an abnormality exists. In the first re-diagnosis, if an abnormality is detected in only one of the first or second abnormality determination processes, the abnormality detection unit determines that an obstacle is in contact with a steering wheel, and implements countermeasures for the presence of an obstacle. The steering wheel is the steering wheel in the direction corresponding to the abnormality determination process in which the abnormality was detected. In the second re-diagnosis, if no abnormality is detected in either the first or second abnormality determination process, the abnormality detection unit determines that everything is normal.

[0377] In the eleventh method, similar to the tenth method, the driving force is increased compared to the first determination to perform a re-diagnosis, i.e., a second re-diagnosis.

[0378] However, unlike the tenth method, in this method, if either the first or second direction is judged as normal in the first judgment and the other direction is judged as abnormal, a second re-diagnosis is performed.

[0379] In this situation, as explained in the ninth method, there is a possibility that the displacement of the steering wheels may be obstructed by obstacles such as curbs. However, instead of making such a judgment immediately, a second re-diagnosis is performed by increasing the driving force as a precaution, in order to reduce the possibility of misjudgment.

[0380] If the result of the second re-diagnosis is the same as the first determination, and only if either the first or second direction is determined to be abnormal, the possibility of obstacles such as curbs is quite high. Therefore, in this case, it is determined that there are obstacles such as curbs, and appropriate countermeasures are taken.

[0381] In addition, during the second diagnostic test performed by increasing the driving force, if an abnormality is detected in either direction, the possibility of abnormalities caused by rust, icing, etc. is high, and therefore it is determined that there is an abnormality.

[0382] In addition, in the second re-diagnosis, if no abnormalities are found in the first and second directions, it is judged as normal.

[0383] In this way, by adding a second diagnosis, it is possible to clearly distinguish and detect the original abnormality caused by rust, ice, etc., and the superficial abnormality caused by the presence of curb stones, etc. In particular, since the accuracy of the determination of the presence of curb stones, etc. is improved, the accuracy of the abnormality determination can be further improved.

[0384] In the twelfth embodiment, which belongs to any of the first to eighth embodiments, the movable part can move in a first direction and a second direction opposite to the first direction, respectively. The elastic body includes a first elastic body that can deform in the first direction by contraction deformation and a second elastic body that can deform in the second direction by contraction deformation. The motor control unit applies a driving force for abnormality detection to the movable part and performs a first action that deforms the first elastic body in the first direction and a second action that deforms the second elastic body in the second direction. In the case where no abnormality is detected in the first abnormality determination process corresponding to the first action and the second abnormality determination process corresponding to the second action, and the result is a first normal determination state that can be determined to be normal, or in the case where an abnormality is detected in at least one of the first abnormality determination process corresponding to the first action and the second abnormality determination process corresponding to the second action, but the result of the re-diagnosis is a second normal determination state that can be determined to be normal, the abnormality detection unit further determines whether the deviation of the measured value of the physical quantity corresponding to the micro-displacement or the stroke value obtained based on the measured value of the micro-displacement itself in the first and second directions exceeds the normal range and is too large. If it is determined to be too large, it is determined that there is an abnormality.

[0385] In the twelfth method, even if the condition is judged to be normal in the first determination or in the second diagnosis, in order to be more cautious and reduce misjudgment, it is determined whether the deviation of friction estimated based on the small displacements in the first and second directions exceeds the normal range and becomes too large.

[0386] In other words, in this method, it is determined whether the frictional deviation estimated based on the minute displacements in the first and second directions, i.e., the frictional force deviation in the first and second directions, is within a predetermined allowable range, or in other words, whether it is within the normal range, or whether it is not within the normal range and thus deemed excessive.

[0387] That is, in the first judgment and the second diagnosis, although it is tentatively determined that there is no abnormality, there is a difference between the stroke amount of the first micro displacement in the first direction and the stroke amount of the second micro displacement in the second direction. Moreover, if the difference in the stroke amount includes a difference that exceeds the preset allowable range or the normal range, that is, if the friction deviation exceeds the normal range and is too large, it can be estimated that in at least one of the first and second directions, the movable part of the steering shaft is likely to have a movement constraint caused by the influence of rust, ice, etc., although the constraint may be slight.

[0388] Therefore, in this approach, an anomaly is carefully identified under such circumstances. This further reduces the possibility of misjudgment.

[0389] In the thirteenth embodiment, which belongs to any of the first to twelfth embodiments, the rotary direct-acting conversion mechanism is a ball screw mechanism, which includes: a ball nut; and a ball bearing having an inner ring portion disposed in the ball nut, an outer ring portion disposed in the housing, and a plurality of balls disposed between the inner ring portion and the outer ring portion. When the outer ring portion is provided with a first end face on one side in the axial direction of the movable member and the opposite side of the outer ring portion is provided with a second end face, an elastic body is provided on at least one of the first end face and the second end face to elastically support the ball bearing in the housing.

[0390] In this approach, a ball screw mechanism, which is versatile, has very low friction loss, and high energy conversion efficiency, is used as the rotary-to-linear conversion mechanism. This, for example, improves the practicality of the steering device to which the present invention is applied.

[0391] In the fourteenth embodiment, which belongs to any of the first to thirteenth embodiments, the transmission mechanism that transmits the driving force generated by the rotation of the motor to the rotary direct-drive conversion mechanism is a reduction mechanism provided between the motor and the ball screw mechanism. It consists of an input pulley on the motor side, an output pulley on the ball screw mechanism side, and a belt wound between the input pulley and the output pulley. The driving component that can deform is the belt.

[0392] In this approach, a highly versatile reducer utilizing pulleys and belts is used as the transmission mechanism. This, for example, improves the practicality of the steering device employing the present invention.

[0393] In the fifteenth embodiment, a steering control device controls the operation of a steering mechanism mounted on a vehicle and steering the vehicle's steering wheels. The steering mechanism includes: a movable part connected to the steering wheels and steering them; a housing covering at least a portion of the movable part and fixed to the vehicle body; a motor applying a steering force to the movable part; a rotary-to-linear conversion mechanism disposed within the housing, converting rotational motion from the motor into linear motion and transmitting it to the movable part; and a transmission mechanism disposed between the rotary-to-linear conversion mechanism and the housing, elastically supporting the rotary-to-linear conversion mechanism within the housing, or disposed between the motor and the rotary-to-linear conversion mechanism, transmitting the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism. The transmission mechanism comprises a deformable driving medium and an elastic body, wherein an anomaly detection process is implemented to detect abnormalities in the normal movement of the movable part that are constrained. The process includes: a first process, generating an abnormality detection driving force by providing an abnormality detection drive command to the motor, and applying the abnormality detection driving force to the movable part. Although the abnormality detection driving force cannot make the movable part move over the frictional force acting on the movable part, it can cause the elastic body or the driving medium and the elastic body, which are conceived to be deformable, to undergo temporary and reversible deformation, respectively; and a second process, measuring the minute displacement of the movable part and obtaining the measured value of the physical quantity corresponding to the minute displacement. If the first stroke amount corresponding to the minute displacement shown by the measured value is smaller than the second stroke amount corresponding to the normal minute displacement generated under no abnormality, an abnormality is determined to exist. The minute displacement corresponds to the deformation of the elastic body or the total deformation of the driving medium and the elastic body, which are conceived to be deformable, during the period when the abnormality detection driving force is applied to the movable part.

[0394] According to this method, a steering control device capable of detecting steering device malfunctions at high speed based on minute displacements can be provided.

[0395] In the sixteenth embodiment, an anomaly detection method for a steering control device detects an anomaly in the steering device, which is mounted on a vehicle and steers the vehicle's steering wheels. The steering device includes: a movable part connected to and steers the steering wheels; a housing covering at least a portion of the movable part and fixed to the vehicle body; a motor applying a steering force to the movable part; a rotary-to-linear conversion mechanism disposed within the housing, converting rotational motion from the motor into linear motion and transmitting it to the movable part; and an elastic body disposed between the rotary-to-linear conversion mechanism and the housing, elastically supporting the rotary-to-linear conversion mechanism within the housing, or a transmission mechanism disposed between the motor and the rotary-to-linear conversion mechanism, transmitting the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism. The anomaly detection method includes: a first step, by providing an anomaly detection method to the motor... The detection process involves generating an abnormality detection driving force using a driving command, and applying this abnormality detection driving force to a movable part. Although this abnormality detection driving force cannot cause the movable part to move despite the frictional force acting on it, it can cause temporary and reversible deformation of the elastic body, or cause temporary and reversible deformation of the driving medium and the elastic body, which are assumed to be deformable. The second step involves measuring the minute displacement of the movable part and obtaining the measured value of the physical quantity corresponding to the minute displacement. If the first stroke amount corresponding to the minute displacement shown in the measured value is smaller than the second stroke amount corresponding to the normal minute displacement generated under normal conditions, an abnormality is determined to exist. This minute displacement corresponds to the total deformation of the elastic body temporarily generated during the application of the abnormality detection driving force to the movable part, or the deformation of the driving medium and the elastic body, which are assumed to be deformable.

[0396] According to this method, a steering device anomaly detection method can be provided that can detect steering device anomalies at high speed based on minute displacements.

[0397] In the seventeenth method, the program is a program that enables the computer to act as the steering control device in the fifteenth method described above.

[0398] According to this method, a program can be provided that enables the easy construction of steering control devices using a computer.

[0399] This invention is not limited to the embodiments described above and can be modified and applied in various ways. For example, various materials can be used as the material of the elastomer and the material of the driving medium such as the belt in the transmission mechanism. In addition, in addition to the structures described in the embodiments, rotary-to-linear conversion mechanisms and transmission mechanisms with various other structures can be used.

[0400] Any method that achieves the intended effects and benefits of this invention is acceptable; this invention is not limited to any particular embodiment.

[0401] [Industry Applicability]

[0402] The present invention is useful, for example, as a steering device in a four-wheeled vehicle.

[0403] Explanation of reference numerals in the attached figures

[0404] 2: Rotation angle sensor

[0405] 5: Motor (Steering Actuator)

[0406] 10: Vehicles

[0407] 24: Motor body

[0408] 25: Motor output shaft

[0409] 26: Movable parts (steering shaft)

[0410] 29: Steering knuckle arm

[0411] 31: Steering wheel (wheel)

[0412] 44: Transmission mechanism (reducer, etc.)

[0413] 50: Casing

[0414] 51: First shell

[0415] 52: Second shell

[0416] 53: Storage Room

[0417] 55: First end face

[0418] 57: Second end face

[0419] 58: Inner circumferential surface

[0420] 61: Input side pulley

[0421] 62: Output side pulley

[0422] 63: Driving medium (tape)

[0423] 70: Rotary-to-direct-drive conversion mechanism (ball screw)

[0424] 71: Threaded section

[0425] 72: Ball bearing

[0426] 73: Nut

[0427] 74: Bearings (Rolling Bearings)

[0428] 74a: Outer circumferential surface of the bearing

[0429] 74b: Outer ring of the bearing

[0430] 75: Support section (ring-shaped support section)

[0431] 80: Elastomer

[0432] 90: Ring

[0433] 113: Shell

[0434] 200: Steering System

[0435] 300: Steering input device

[0436] 301: Steering Wheel

[0437] 302: Steering shaft

[0438] 303: Operating Angle Sensor

[0439] 304: Operating torque sensor

[0440] 305: Reaction motor (reaction actuator)

[0441] 403: Motor Control Unit

[0442] 405: Self-diagnosis assessment department

[0443] 406: Motor History Accumulation Department

[0444] 407: Driver instruction issuing unit for anomaly detection

[0445] 409: Anomaly Detection Department

[0446] 411: Anomaly Detection Department

[0447] 413: Threshold setting unit

[0448] 415: Threshold Determination Unit

[0449] 417: Temperature sensor

[0450] 500: Steering control device (control device)

[0451] 501: Control Department

[0452] 503: Memory

[0453] 505: Procedure

[0454] 509: Small Gear

[0455] 510: Rotation Angle Sensor

[0456] 511: Non-contact sensors (non-contact displacement sensors, optical displacement sensors)

[0457] 513: Mark

[0458] 515: Light-emitting part

[0459] 517: Light-receiving part

[0460] 600: Various sensors

[0461] 601: ECU (Electronic Control Unit)

[0462] 603: Notification Department

[0463] 610: Worm Gear

[0464] 620: Worm Gear

[0465] 622: Shaft

[0466] 630: First Bearing

[0467] 640: Second bearing

[0468] 650: Connector

[0469] 653: Bushing (elastic component)

[0470] 700: Steering mechanism

[0471] 700A: Elastomer (First worm gear damper)

[0472] 700B: Elastomer (Second worm gear damper)

[0473] 800: Steering gear

[0474] DR1: First direction (e.g., left)

[0475] DR2: Second direction (e.g., right side)

[0476] Abn: Rust, ice, and other obstacles that hinder movement.

Claims

1. A steering device mounted on a vehicle to steer the vehicle's steering wheels, wherein, The steering device has: A movable part that is connected to the steering wheel and causes the steering wheel to turn; A housing that covers at least a portion of the movable part and is fixed to the body of the vehicle; A motor that applies a steering force to the movable part; A rotary-to-linear conversion mechanism, disposed within the housing, converts the rotary motion transmitted from the motor into linear motion and transmits it to the movable component; An elastomer is disposed between the rotary-to-linear conversion mechanism and the housing, which elastically supports the rotary-to-linear conversion mechanism on the housing; as well as The control device, in response to the fulfillment of a triggering condition or a predetermined condition that serves as confirmation of action, outputs a first control signal to the motor, causing the rotary direct motion conversion mechanism to move relative to the movable member by a displacement amount corresponding to the elastic support amount of the elastic body. It acquires a physical quantity related to the movement amount of the movable member based on the first control signal, and determines whether there is an abnormality based on the physical quantity related to the movement amount of the movable member. If an abnormality is determined, it outputs an abnormality judgment signal.

2. The steering device according to claim 1, wherein, The steering device has a first structure or a second structure. In the first structure, the elastic body is the only structural element that undergoes temporary and reversible deformation during the period when a drive command for anomaly detection, which is the first control signal, is provided to the motor. In the second structure, in addition to the elastic body, there is also a transmission mechanism disposed between the motor and the rotary-to-linear conversion mechanism, which is conceived to be deformable and includes a transmission medium that transmits the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism. The control device includes a motor control unit for controlling the motor and an anomaly detection unit for detecting abnormalities in the normal movement of the movable part that are constrained. When the motor control unit detects the abnormality, it generates a driving force for abnormality detection by providing the motor with a drive command for abnormality detection, which serves as the first control signal. This driving force is then applied to the movable member. Although the driving force for abnormality detection cannot cause the movable member to move despite the friction acting on it, it can deform the elastomer or cause both the deformable drive medium and the elastomer to deform. The anomaly detection unit measures the minute displacement of the movable part and obtains the measured value of the physical quantity corresponding to the minute displacement. This minute displacement corresponds to the temporary and reversible deformation of the elastic body generated during the application of the driving force for anomaly detection to the movable part, or the total deformation of the driving medium and the elastic body, which are conceived to be deformable. If the first stroke corresponding to the minute displacement shown in the measured value is smaller than the second stroke corresponding to the normal minute displacement generated without the anomaly, it is determined that there is an anomaly.

3. The steering device according to claim 2, wherein, The deformation of the elastic body generated during the application of the driving force for anomaly detection to the movable part is the maximum elastic deformation that the elastic body can deform. Or, The total deformation of the driving medium and the elastomer, which are temporarily generated during the period when the driving force for anomaly detection is applied to the movable part, is the total deformation obtained by adding the maximum elastic deformation that can be deformed in the elastomer to the normal deformation that can be conceived in the driving medium when the driving force for anomaly detection is generated.

4. The steering device according to claim 2, wherein, The measured value of the physical quantity corresponding to the minute displacement is at least one of the following: the detected value of the rotation angle of the motor, the detected value of the rotation angle of the pinion meshing with the rack, which is the movable component, and the detected value obtained by detecting the displacement of the rack, which is the movable component, using a non-contact sensor.

5. The steering device according to claim 2, wherein, The anomaly detection unit performs a threshold-based determination when it determines that an anomaly has occurred. When the first case is defined as the deformation of only the elastomer, and the second case is defined as the deformation of both the deformable driving medium and the elastomer, respectively... In the first case, the threshold is set to a stroke value smaller than the stroke value of the small displacement corresponding to the maximum elastic deformation that the movable part can deform. In the second case, the threshold is set to a stroke value that is larger than the stroke value of the minute displacement corresponding to the maximum elastic deformation that the elastomer can deform, and smaller than the stroke value of the minute displacement corresponding to the following total deformation, which is the total deformation obtained by adding the maximum elastic deformation that the elastomer can deform to the normal deformation that the driving medium can conceive when the driving force for the anomaly detection is generated.

6. The steering device according to claim 5, wherein, The anomaly detection unit variably controls the threshold based on at least one of the vehicle's ambient temperature and the vehicle's driving history.

7. The steering device according to claim 2, wherein, The motor control unit and the anomaly detection unit perform self-diagnostic processing to determine whether the anomaly exists when the vehicle is not in motion.

8. The steering device according to claim 2, wherein, When the vehicle is stopped with the start switch on and there is no steering input from the vehicle's occupants, the motor control unit and the anomaly detection unit perform a self-diagnostic process to determine whether the anomaly exists.

9. The steering device according to claim 2, wherein, The movable component can move in a first direction and in a second direction, which is opposite to the first direction. The elastic body includes a first elastic body capable of deforming in the first direction through contraction deformation, and a second elastic body capable of deforming in the second direction through contraction deformation. The motor control unit applies the driving force for anomaly detection to the movable component, and respectively performs a first action to deform the first elastic body in the first direction and a second action to deform the second elastic body in the second direction. If the anomaly detection unit detects an anomaly in either the first anomaly determination process corresponding to the first action or the second anomaly determination process corresponding to the second action, it determines that there is an anomaly.

10. The steering device according to claim 9, wherein, If the control device detects an anomaly in either the first anomaly detection process or the second anomaly detection process, it performs a first re-diagnosis before determining that an anomaly has occurred. When the driving force for detecting the anomaly applied to the movable part during the first anomaly determination process or the second anomaly determination process is set as the first driving force. In the first re-diagnosis, the motor control unit applies a second driving force, which is greater than the first driving force, to the movable part to re-implement the first anomaly determination process and the second anomaly determination process. In the first re-diagnosis, if an abnormality is detected in both the first abnormality determination process and the second abnormality determination process, the abnormality detection unit determines that an abnormality exists. In the first re-diagnosis, if an abnormality is detected in either the first abnormality determination process or the second abnormality determination process, the abnormality detection unit determines that an obstacle is in contact with a steering wheel, and implements countermeasures for the presence of an obstacle. This steering wheel is the steering wheel in the direction corresponding to the abnormality determination process that detected the abnormality. In the first re-diagnosis, if no abnormality is detected in either the first abnormality determination process or the second abnormality determination process, the abnormality detection unit determines that it is normal.

11. The steering device according to claim 2, wherein, The movable component can move in a first direction and in a second direction, which is opposite to the first direction. The elastic body includes a first elastic body capable of deforming in the first direction through contraction deformation, and a second elastic body capable of deforming in the second direction through contraction deformation. The motor control unit applies the driving force for anomaly detection to the movable component, and respectively performs a first action to deform the first elastic body in the first direction and a second action to deform the second elastic body in the second direction. If an anomaly is detected in either the first anomaly detection process corresponding to the first action or the second anomaly detection process corresponding to the second action, the anomaly detection unit performs a second re-diagnosis before determining that an anomaly has occurred. When the driving force for detecting the anomaly applied to the movable part during the first anomaly determination process or the second anomaly determination process is set as the first driving force. In the second re-diagnosis, the motor control unit applies a third driving force, which is greater than the first driving force, to the movable part to re-implement the first anomaly detection process and the second anomaly detection process. In the second re-diagnosis, if an abnormality is detected in both the first and second abnormality determination processes, the abnormality detection unit determines that an abnormality exists. In the first re-diagnosis, if an abnormality is detected in either the first abnormality determination process or the second abnormality determination process, the abnormality detection unit determines that an obstacle is in contact with a steering wheel, and implements countermeasures for the presence of an obstacle, wherein the steering wheel is the steering wheel in the direction corresponding to the abnormality determination process in which the abnormality was detected. In the second re-diagnosis, if no abnormality is detected in either the first abnormality determination process or the second abnormality determination process, the abnormality detection unit determines that it is normal.

12. The steering device according to claim 2, wherein, The movable component can move in a first direction and in a second direction, which is opposite to the first direction. The elastic body includes a first elastic body capable of deforming in the first direction through contraction deformation, and a second elastic body capable of deforming in the second direction through contraction deformation. The motor control unit applies the driving force for anomaly detection to the movable component, and respectively performs a first action to deform the first elastic body in the first direction and a second action to deform the second elastic body in the second direction. If no abnormality is detected in either the first abnormality determination process corresponding to the first action or the second abnormality determination process corresponding to the second action, resulting in a first normal determination state that can be determined as normal, or if an abnormality is detected in at least one of the first abnormality determination process corresponding to the first action or the second abnormality determination process corresponding to the second action, but the result of the re-diagnosis is a second normal determination state that can be determined as normal, the abnormality detection unit further determines whether the deviation of the measured value of the physical quantity corresponding to the micro-displacement or the travel value obtained based on the measured value of the micro-displacement itself in each of the first and second directions exceeds the normal range and is too large. If it is determined to be too large, it is determined that there is an abnormality.

13. The steering device according to claim 2, wherein, The rotary-to-linear conversion mechanism is a ball screw mechanism. The ball screw mechanism includes: a ball nut; and a ball bearing having an inner ring portion disposed in the ball nut, an outer ring portion disposed within the housing, and a plurality of balls disposed between the inner ring portion and the outer ring portion. When the outer ring portion is designated as a first end face on one side of the movable member along the axial direction, and the side of the outer ring portion opposite to the first end face is designated as a second end face, an elastic body is provided on at least one of the first end face and the second end face to elastically support the ball bearing to the housing.

14. The steering device according to claim 2, wherein, The transmission mechanism that transmits the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism is a reduction mechanism disposed between the motor and the ball screw mechanism. It consists of an input-side pulley on the motor side, an output-side pulley on the ball screw mechanism side, and a belt wound between the input-side pulley and the output-side pulley. The driving component capable of undergoing the aforementioned deformation is the belt.

15. A steering control device for controlling the operation of a steering mechanism mounted on a vehicle and steering the steering wheels of the vehicle, the steering mechanism comprising: A movable part that is connected to the steering wheel and causes the steering wheel to turn; A housing that covers at least a portion of the movable part and is fixed to the body of the vehicle; A motor that applies a steering force to the movable part; A rotary-to-linear conversion mechanism, disposed within the housing, converts the rotary motion transmitted from the motor into linear motion and transmits it to the movable component; as well as The transmission mechanism, disposed between the rotary-to-linear conversion mechanism and the housing, elastically supports the rotary-to-linear conversion mechanism against the elastic body of the housing, or disposed between the motor and the rotary-to-linear conversion mechanism, transmits the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism. This transmission mechanism comprises a deformable driving medium and the elastic body. in, An anomaly detection process is implemented to detect abnormalities in the normal movement of the movable part that are constrained. The anomaly detection process includes: The first process involves generating an anomaly detection driving force by providing an anomaly detection drive command to the motor, and applying this anomaly detection driving force to the movable part. While this anomaly detection driving force cannot cause the movable part to move against the frictional force acting on it, it can cause temporary and reversible deformation of the elastomer, or cause temporary and reversible deformation of both the driving medium and the elastomer, which are conceived to be capable of such deformation. The second process involves measuring the minute displacement of the movable part and obtaining a measured value of the physical quantity corresponding to the minute displacement. If the first stroke amount corresponding to the minute displacement shown in the measured value is smaller than the second stroke amount corresponding to the normal minute displacement generated in the absence of the abnormality, an abnormality is determined to exist. The minute displacement corresponds to the deformation of the elastic body during the application of the driving force for abnormality detection to the movable part, or the total deformation of the driving medium that is assumed to be deformable and the elastic body.

16. A method for detecting an anomaly in a steering device, comprising: detecting an anomaly in the steering device, the steering device being mounted on a vehicle and steerable the vehicle's steering wheels, the steering device comprising: A movable part that is connected to the steering wheel and causes the steering wheel to turn; A housing that covers at least a portion of the movable part and is fixed to the body of the vehicle; A motor that applies a steering force to the movable part; A rotary-to-linear conversion mechanism, disposed within the housing, converts the rotary motion transmitted from the motor into linear motion and transmits it to the movable component; as well as The transmission mechanism, disposed between the rotary-to-linear conversion mechanism and the housing, elastically supports the rotary-to-linear conversion mechanism against the elastic body of the housing, or disposed between the motor and the rotary-to-linear conversion mechanism, transmits the driving force generated by the rotation of the motor to the rotary-to-linear conversion mechanism. This transmission mechanism comprises a deformable driving medium and the elastic body. in, The anomaly detection method includes: The first step involves generating an anomaly detection driving force by providing an anomaly detection drive command to the motor, and applying this anomaly detection driving force to the movable part. While this anomaly detection driving force cannot cause the movable part to move against the frictional force acting on it, it can cause temporary and reversible deformation of the elastomer, or cause temporary and reversible deformation of both the deconstructible driving medium and the elastomer. The second step is to measure the minute displacement of the movable part and obtain the measured value of the physical quantity corresponding to the minute displacement. If the first stroke amount corresponding to the minute displacement shown in the measured value is smaller than the second stroke amount corresponding to the normal minute displacement generated in the absence of the abnormality, it is determined that there is an abnormality. The minute displacement corresponds to the deformation of the elastic body that is temporarily generated during the application of the driving force for abnormality detection to the movable part, or the total deformation of the driving medium and the elastic body, which are assumed to be deformable.

17. A program that causes a computer to operate as the steering control device of claim 15.

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