JP3925422B2 - Steering device abnormality detection device and steering device abnormality detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention detects an abnormality in a vehicle steering system in which wheel steering is performed by a driving force of a driving source different from the operating member or by a driving force of an operating member assisted by a driving force of another driving source. The present invention relates to an apparatus and a method.
[0002]
[Prior art]
The vehicle steering apparatus includes a so-called power steering that steers a wheel by assisting a driving force input from an operation member such as a steering wheel by a driving force of a separately provided driving source, and an operation unit including a steering wheel. Steering unit that steers the wheel is mechanically separated, and the steering unit that steers the wheel according to the operation of the steering wheel by the drive source provided in the steering unit, etc. Exists. In general, the steering device has a steering rod (for example, a rack bar) whose both ends are respectively connected to the steering knuckles of the left and right wheels, and the wheels are moved by moving the steering rod in the lateral direction of the vehicle. Is steered. The steering device including the drive source has a structure in which the wheel is steered depending on the drive force of the drive source, and therefore an abnormality occurs in the drive source and the drive transmission path from the wheel to the wheel. It is hoped that it will be discovered early.
[0003]
In a power steering apparatus that uses an electric motor as a drive source, for example, techniques described in the following patent documents exist as techniques for finding an abnormality in the electric motor. This technique is intended to detect a load short-circuit fault of a drive source by detecting a load current of a motor.
[0004]
[Patent Document 1]
Japanese Patent No. 3274377
[0005]
[Problems to be solved by the invention, means for solving problems and effects]
In the steering apparatus including the driving source, as described above, the driving force from the driving source is transmitted as the steering driving force of the wheels via, for example, the steering rod. An abnormality may occur. For example, it is generated when a meshing part such as a gear or a ball screw, a bearing part holding a rotating body such as a gear constituting a reduction mechanism that decelerates the output shaft of the motor or the rotation of the output shaft, or the like is damaged. It is abnormal. However, for example, such an abnormality in the driving force transmission path cannot be found even with the above-described prior art.
[0006]
Then, this invention is made | formed as a subject to obtain the apparatus and method which detect abnormality of the steering part of the steering apparatus provided with the drive source different from the operation member, and according to this invention, The steering device abnormality detection device and the steering device abnormality detection method of each aspect are obtained. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating understanding of the present invention, and should not be construed as limiting the technical features described in the present specification and the combinations thereof to those described in the following sections. . In addition, when a plurality of items are described in one section, it is not always necessary to employ the plurality of items together. It is also possible to select and employ only some items.
[0007]
In addition, although some of the aspects obtained by the present invention are listed as claimed inventions, the following items and the claimed invention will be described. 1 is the sum of the items (2) to (4) in claim 2, the claim (6) is in claim 3, and the sum of items (7) and (10) is claimed. The combination of item (4) with item (11) and item (12) corresponds to item 5 and item (13) corresponds to item 6. The (21) term corresponds to the seventh claim.
[0008]
(1) (a) An operation unit including an operation member operated by a driver for steering, and (b) a drive motor, which is driven by the rotational driving force of the motor, or the rotational driving force of the motor. An apparatus for detecting an abnormality in the steering unit of a vehicle steering device including a steering unit that is driven by a driving force from the operation unit assisted by the steering unit and steers a wheel according to an operation of the operation member Because
Rotation drive body that exists in the transmission path of the rotation drive force of the drive motor or the drive motor and is driven to rotate by itself The fluctuation state of the physical factor value directly or indirectly indicating the rotation state of the drive motor within the set rotation angle of the drive motor or the rotary drive body is detected. A fluctuation detector;
Based on the detected fluctuation state, an abnormality recognition unit that recognizes that the steering unit is abnormal; and
A steering device abnormality detection device comprising:
[0009]
To put it simply, the abnormality detection device described in this section measures a parameter indicating the rotation state of a drive motor or a rotary driving body rotated by the motor in a certain relatively short span, and the variation state of the parameter. Therefore, an abnormality of the steered portion is detected. As described above, in particular, an abnormality in the driving force transmission path from the motor to the steered wheels, for example, an abnormality of the steered portion due to an abnormality occurring in each component constituting the driving force transmission path is discovered. Is a suitable abnormality detection device.
[0010]
For example, as described above, foreign matters are mixed in or bitten on each part of the transmission mechanism such as a bearing that holds a rotary drive body such as a motor output shaft and a gear that is rotationally driven by the output shaft. And abnormalities occur in the drive transmission path due to rust, damage, etc. of those parts. These abnormalities hinder the smooth rotation of the motor or the rotational drive body (hereinafter may be abbreviated as “motor etc.”), so that physical factor values such as rotational speed (detailed later) are abnormal. Appears as a variation. As will be described in detail later, the fluctuations often appear as, for example, periodic fluctuations according to the rotation period of the motor or the like, or appear as fluctuations at a certain turning angle position. If it judges, those abnormalities in a steering part can be detected easily. The abnormality of the steered portion can be experienced by the operator as a change in the feeling of operation of the vehicle if the degree of the abnormality becomes large, but it is sufficiently small in the initial stage of the abnormality and can be experienced. Have difficulty. According to the abnormality detection device described in this section, it is possible to detect even a small abnormality in the initial stage that the operator cannot feel.
[0011]
In the aspect described in this section, the type of the “drive motor” serving as the drive source is not particularly limited. Various types of electric motors that are rotationally driven can be used. In addition, the “rotary drive body” is, for example, a device that is driven depending on the driving force of the driving motor, that is, when the steered rod is driven depending on the driving force of the driving motor. It may be provided for the purpose of driving force transmission between the rudder rod. In that case, the rotational drive of the drive motor may be transmitted at a reduced speed, or may be transmitted at a constant speed or increased. For example, in a steered portion that includes a steered rod provided with a rack, a pinion that meshes with the rack, and a drive motor that rotates the pinion or moves the drive rod, the pinion or the pinion The shaft functions as a rotary drive. Further, in a steered portion that includes a steered rod in which a ball screw is formed, a nut that is screwed to the ball screw, and a drive motor that rotates the nut, the nut serves as a rotational drive body. Function.
[0012]
For example, a steering wheel is generally used as the “operation member”, but the shape, method, and the like are not particularly limited. For example, in the above-described operation unit / steering unit separation type steering device, it is only necessary to be able to acquire an operation amount for determining the turning angle, and in extreme cases, various devices such as a joystick are adopted. Is possible. The meanings of “set rotation angle”, “physical factor”, “variation state”, specific aspects of “variation detection unit”, “abnormality recognition unit”, etc. will be described in the following sections.
[0013]
(2) The fluctuation detection unit includes a rotation speed fluctuation detection unit that detects a fluctuation state of a rotation speed of the drive motor or the rotary drive body as a fluctuation state of the physical factor value. Steering device abnormality detection device.
(3) The variation detection unit includes a rotational torque variation detection unit that detects a variation state of the rotational torque of the drive motor or the rotary drive body as the variation state of the physical factor value. The steering device abnormality detection device according to item).
(4) The variation detection unit includes a load variation detection unit that detects a variation state of the load of the drive motor as the variation state of the physical factor value. Steering device abnormality detection device.
[0014]
In the anomaly detection device of the present invention, the “physical factor value” used for detecting the fluctuation state is not particularly limited, and may be a wide variety of parameters as long as it is a parameter representing the rotation state of a motor or the like. You can adopt things. Each of the above three terms is a term limited to a specific one that can use the “physical factor value”. Any of the “physical factor values” exemplified in these terms can be obtained relatively easily, and they change according to the force that inhibits the rotation of the motor, etc. It is a parameter that is easy to recognize. For example, when it is assumed that the operation member is operated at a constant speed, the three factor values are theoretically constant values or values that gradually change during the operation. However, for example, even if it is controlled to supply a constant current value to the drive motor, if the foreign matter is mixed or damaged, the rotational speed of the motor or the like is slowed according to the state of occurrence. . On the other hand, even if it is controlled to rotate at a constant speed, the load current indicating the motor load increases and the rotational torque also increases. Therefore, when the above abnormality occurs in the steered portion, those physical factor values cause abnormal fluctuations. Thus, the fluctuation of the physical factor value can be an effective index indicating abnormality.
[0015]
In the above item (2), the “rotational speed” may be a rotational angular speed or a peripheral speed. The measurement device for each physical factor value is not particularly limited. For example, if the rotation angular velocity, the rotation phase is measured by a measurement device such as a resolver and is calculated from the amount of change in the rotation phase over time. Can do. It can also be calculated on the basis of the number of pulses acquired during the passage of a predetermined time by a measuring device such as an encoder or an electromagnetic pickup. Further, for example, a peripheral speed meter or the like can be employed for the peripheral speed, and various torque sensors can be employed for the rotational torque. Note that the measurement of the rotational torque is not limited to a mode in which the torque of the motor or the like is directly measured, but is another constituent element that constitutes the steered portion, and the constituent element in which the rotational torque fluctuation of the motor or the like appears as its own torque fluctuation The torque may be measured and the torque fluctuation of the motor or the like may be indirectly measured. When the load of the drive motor appears in the magnitude of the load current as in a general electric motor, it is only necessary to detect the load current, and various ammeters can be employed as the measuring device.
[0016]
The above three terms relate to an aspect having a “rotational speed fluctuation detection unit”, “rotational torque fluctuation detection unit”, and “load fluctuation detection unit”, respectively, depending on the object of detection. As will be understood from the paragraphs, the abnormality detection device of the present invention may be configured to include only one of the three detection units, or may be configured to include two or more. In other words, it is also possible to detect a variation state of two or more types of factor values and to recognize an abnormality based on them.
[0017]
(5) The variation detector detects a difference between the maximum value and the minimum value of the physical factor value within the set rotation angle as the variation state of the physical factor value. The steering device abnormality detection device according to any one of (4).
[0018]
In the abnormality detection device of the present invention, there is no limitation on what value the variation state of the physical factor value within the set rotation angle is. For example, as shown in this section, the variation state value can be determined by the difference between the maximum value and the minimum value of the factor values measured within the rotation angle. The difference between the factor value and the end of measurement can be used as the fluctuation state value. In addition, the maximum value of the measured change gradient of the factor value can be used as the fluctuation state value. As described in this section, the difference between the maximum value and the minimum value can be calculated easily, and if that value is adopted as the fluctuation state value, the factor value generated within a rotation angle smaller than the set rotation angle. Even if it is an abnormal fluctuation, it will be reflected in the value.
[0019]
(6) The steering apparatus abnormality detection device according to any one of (1) to (5), wherein the set rotation angle is an angle corresponding to one rotation of the drive motor or the drive rotor.
[0020]
The physical factor value varies depending on the operation speed of the operation member. For example, the fluctuation increases when the operation speed suddenly increases, such as when the steering wheel is suddenly operated. Therefore, if the rotation angle range at the time of detection is too large, the difference between the factor value at the start of measurement and the factor value at the end of measurement increases, so even if the difference between the maximum value and the minimum value is the fluctuation state value Even if it is adopted, it becomes difficult to detect fluctuations caused by abnormalities. In view of this, it is desirable to detect a variation in the factor value in a relatively small angle range. That is, it is desirable to shorten the fluctuation detection span. Specifically, the full rotation angle of the motor, etc., during the entire turning stroke (the turning stroke when turning from the state steered to the set limit in one direction to the set limit in the other direction) It is desirable to set it to 1/15 or less. More preferably, it should be 1/20 or less, and more preferably 1/25 or less. In addition, as described above, when foreign matter, damage, etc. are present in the motor, etc., the fluctuation of the factor value caused by them is a periodic fluctuation with a period of one rotation of the motor, etc., particularly in the initial stage of abnormality. It may appear in a form, or may appear continuously in each cycle. Considering this, it is desirable that the “set rotation angle” corresponds to one rotation of the motor or the like as in the aspect described in this section. The set rotation angle may be an angle corresponding to 2 rotations, 3 rotations, or the like, and conversely, an angle corresponding to 1/2 rotation, 1/3 rotation, or the like.
[0021]
(7) Item (1) to Item (6), wherein the variation detection unit performs one-time detection of the variation state of the physical factor value within the set rotation angle in accordance with a predetermined condition. The steering device abnormality detection device according to claim 1.
[0022]
For example, even if the variation of the factor value detected in one detection is large, the variation is not caused by the abnormality of the steered portion, but the operation member is subjected to extreme operation or reaction from the road surface. There is a possibility that it is caused by force. In addition, in the case of mixing of foreign matter, it may be temporary and may not lead to an abnormality of the steered portion. In consideration of such a situation, it is desirable to recognize the abnormality of the steered portion by a plurality of detections under the condition of the same fluctuation detection span as in the aspect described in this section.
[0023]
(8) The steering according to (7), wherein the variation detection unit includes a continuous detection unit that performs the detection once in a plurality of times during one operation of the operation member. Device abnormality detection device.
(9) The rotational angle position of the drive motor or drive rotor is associated with the turning angle of the wheel,
(7) or (8), wherein the variation detection unit includes a specific angle position detection unit that performs the detection once at a specific rotation angle position corresponding to a specific turning angle at a plurality of times. Steering device abnormality detection device.
[0024]
The modes described in the above two items are modes in which a condition for performing detection a plurality of times, in other words, a limitation regarding sampling conditions is added. The mode of item (8) includes, for example, a mode in which fluctuation detection is continuously performed in one operation of turning the handle or one operation of returning the handle. For example, every time a motor or the like rotates by a set rotation angle, one detection starts and ends. Specifically, the detection starts and ends every rotation of the motor or the like, that is, every 360 ° rotation. There is an advantage that the number of samples for fluctuation detection can be increased. In addition, the mode in which detection is performed continuously includes, for example, a mode in which the detection span is a set rotation angle, but the detection start timing is set to a smaller angle pitch. That is, this is a mode in which detection is performed a plurality of times with detection periods partially overlapping while moving the fluctuation detection span. Even if the rotation angle in one operation is the same, the number of detections can be further increased if the variation detection span is moved and measured. Instead of the mode described in the item (8), a mode is provided with an intermittent detection unit that performs the one-time detection intermittently over a plurality of times during one operation of the operation member. You can also. This mode is a mode in which intervals are provided in each fluctuation detection span. For example, after the end of one detection, after the rotation by a predetermined rotation angle, or after a predetermined time elapses, the next detection is started. Is included. There is an advantage that the number of samplings for fluctuation detection in one operation can be reduced.
[0025]
The aspect described in the above item (9) is an aspect in which fluctuation detection is performed at a rotational angle position of a motor or the like corresponding to a certain turning angle in a steerable range. For example, in the driving force transmission unit from the motor or the like to the steered rod, if there is damage or the like on the steered rod side, the above factor value at a certain position in the steerable range, that is, at a certain steered angle position. There is a high possibility that abnormal fluctuations will occur. In such a case, it is desirable to set the position as the specific rotation angle position and to manage the abnormal fluctuation of the position with priority. The embodiment described in the item (9) is a preferable embodiment in such a case. The specific rotation angle position may be a section having a predetermined width, such as a set rotation angle that is a fluctuation detection span. Moreover, it is good not only to make only one position into a specific rotation angle position, but it is good also considering a some position as a specific rotation angle position, respectively. That is, this is a mode in which a variation in the factor value is detected at a plurality of specific rotation angle positions.
[0026]
The above two terms relate to an aspect having each of a “continuous detection unit” and a “specific angle position detection unit” according to the sampling conditions. The abnormality detection device of the present invention may be configured to include only one of the two detection units, or may include both. For example, a mode in which a part of detection results in continuous detection is used as a detection result at a specific position is also included.
[0027]
(10) The abnormal time recognition unit that, when the fluctuation state detected in the one-time detection exceeds a set threshold state, recognizes that time as an abnormal time, and the abnormality The steering device abnormality detection device according to any one of items (7) to (9), further including an abnormal time appearance state dependence recognition unit that recognizes that the steering unit is abnormal based on the appearance state of the times.
[0028]
In order to recognize the abnormality of the steered portion, it is desirable to carry out according to some condition. In the mode described in this section, for example, when the fluctuation state in one detection exceeds the set condition, it is recognized as abnormal fluctuation, and when the abnormal fluctuation appears beyond the set condition, A mode for identifying an abnormality is included. Even if there is an abnormal fluctuation of the factor value, the abnormal fluctuation is not caused by an abnormality of the steered part, but is caused by an abrupt operation of the operation part or an abnormal reaction from the road surface, for example. It may be due to power. Such abnormal fluctuation is due to disturbance and becomes so-called noise when an abnormality of the steered portion is detected. According to the “abnormality recognition unit” with the configuration described in this section, the judgment based on the appearance state of abnormal times is performed according to the conditions set by appropriate conditions, thereby performing the authorization without the influence of disturbance. It is possible.
[0029]
(11) The abnormal times appearance state dependency recognition unit includes a frequency dependency determination unit that determines that the steering unit is abnormal when the frequency of occurrence of the abnormal times exceeds a set threshold frequency (10 The steering device abnormality detection device according to item).
(12) When the abnormal times appearance state-based authorization unit continues beyond the threshold number of times when the abnormal times are set, the abnormal times continuous time certification unit that authorizes that the turning unit is abnormal ( The steering device abnormality detection device according to item 10) or (11).
[0030]
The above two terms relate to limitations related to the certification conditions of the abnormal times appearance state certification unit. In any aspect, if the “threshold frequency” and “threshold number” are appropriate, it is possible to eliminate the influence of disturbance and perform appropriate abnormality recognition. For example, when the ratio exceeds a predetermined ratio, it is determined based on the ratio of abnormal times that occurred in the most recent detection times that have been set. The aspect etc. which recognize as abnormality of a steering part are included. In addition, the abnormality detection device of the present invention can also be implemented in a mode having only one of the “frequency-based authorization unit” and the “abnormal times certification unit”, both of which have both It can also be implemented in such a manner that it can function selectively or both perform the authorization process in parallel.
[0031]
(13) The rotational angle position of the drive motor or the drive rotator is associated with the turning angle of the wheel,
Item (10) to (12), wherein the abnormality recognition unit includes a specific angle position recognition unit that performs the recognition of the abnormality and performs the recognition of the abnormality with respect to a specific rotation angle position corresponding to a specific turning angle. The steering device abnormality detection device according to any one of the items.
[0032]
The mode described in this section is a mode for identifying an abnormality that has occurred at a specific rotation angle position. The mode described in this section includes a mode in which the certification based on the appearance frequency as described above, the certification based on continuous occurrence, and the like are performed at the specific rotation angle position. As described above, for example, in the case where there is damage or the like in a specific part on the side of the steering rod in the driving force transmission unit from the motor or the like to the steered rod, when abnormally managing the specific part This is a preferred embodiment.
[0033]
(14) Any one of the items (1) to (13), wherein the steering unit is a vehicle steering device that is driven not by the driving force of the operation unit but by the rotational driving force of the driving motor. The steering device abnormality detection device according to claim 1.
[0034]
The mode described in this section is a mode that targets the above-described steering unit of the operation unit / steering unit separation type, that is, a so-called steer-by-wire type steering device. In the case of a separate operating unit / steering unit type steering device, the abnormal fluctuation of the steering unit is not transmitted to the operating member. I don't get it. Therefore, the abnormality detection device of the present invention that can detect the abnormality of the steered portion has a great merit that is applied to such an operation unit / steered portion separated type steering device. In the case of a power steering device that assists the operation force of the operation member with the driving force of the drive motor, a certain degree of abnormality can be recognized by the operator through the operation member, but still a small abnormality in the initial stage can be recognized. It is difficult for the operator to experience it. In view of the fact that an abnormality can be detected early before the abnormality increases, the abnormality detection device of the present invention can enjoy a sufficient merit even when the power steering device is targeted.
[0035]
(21) (a) An operation unit including an operation member operated by a driver for steering, and (b) a drive motor, which is driven by the rotational driving force of the motor, or the rotational driving force of the motor. A method of detecting an abnormality in the steering unit of a vehicle steering apparatus including a steering unit that is driven by a driving force from the operation unit assisted by the steering unit and steers a wheel in accordance with an operation of the operation member Because
Rotation drive body that exists in the transmission path of the rotation drive force of the drive motor or the drive motor and is driven to rotate by itself The fluctuation state of the physical factor value directly or indirectly indicating the rotation state of the drive motor within the set rotation angle of the drive motor or the rotary drive body is detected. A variation detection step;
Based on the detected fluctuation state, an abnormality recognition step for certifying that the steered portion is abnormal; and
The steering apparatus abnormality detection method characterized by including.
[0036]
The aspect described in this section relates to a method for detecting an abnormality of the steering apparatus, and includes the above-described variation detection step and abnormality recognition step. Since the description of the aspect of this section overlaps with the description of the abnormality detection apparatus described above including the section (1), the description will be omitted to avoid complication. In addition, the abnormality detection method of the present invention can be implemented in a mode in which the technical contents described in the items (2) to (14) are applied to this item. Since the description of these aspects is the same as the description described in each section, the description thereof will be omitted for simplification of the specification.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, but includes the embodiments described in the above section [Problems to be solved by the invention, problem-solving means and effects]. As described above, the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art.
[0038]
<First Embodiment>
i) Overall structure of the steering system
FIG. 1 schematically shows the overall configuration of a vehicle steering apparatus including an abnormality detection apparatus as an embodiment of the present invention. The present steering device is a separate operating unit / steering unit type steering device having a structure in which the operating unit 10 and the steered unit 12 are mechanically separated. In addition to the operating unit 10 and the steered unit 12, an operation is performed. A steering electronic control unit (steering ECU) 14 that is a control device for turning the wheel according to the operation of the unit 10 is configured.
[0039]
The operation unit 10 operates the steering wheel 20 as an operation member, an operation angle sensor 22 for detecting an operation angle that is an operation position of the steering wheel 20, and an operation response to the steering wheel 20 so that the operator can feel a steering feeling. An operation reaction force applying device 24 for applying force is included. The operation reaction force applying device 24 includes a reaction force motor 26 that is an electric motor and a speed reducer 28 that is a speed reducer. And the output shaft 34 is connected to the steering wheel 20, so that a relatively large operation reaction force can be applied even with a relatively small rotational driving force of the reaction force motor 26. The operation angle sensor 22 is mainly composed of a rotary encoder, and can detect an operation angle in the left-right rotation direction from the neutral position of the steering wheel 20. Since the operation reaction force applying device 24 and the operation angle sensor 22 are well known, detailed description thereof will be omitted. In addition, the structure of the operation part 10 is not limited to the above-mentioned thing, The operation part of an already well-known various structure can be employ | adopted for this steering apparatus.
[0040]
The steered portion 12 includes a rod driving device 52 that functions as an actuator for steering and moves the steered rod 50 in the vehicle width direction, and each end of the steered rod 50 has a tie rod 54 and a knuckle arm 56. And connected to each of the left and right steered wheels 58.
[0041]
FIG. 2 shows a cross-sectional view of the rod driving device 52. The rod driving device 52 includes a housing 60 that includes three housing members 60a, 60b, and 60c, and a steering motor 62 that is an electric motor as a drive source therein. The steered motor 62 includes a stator 66 including a coil 64 circumferentially provided on the inner surface of a housing member 60a having a substantially cylindrical shape, a magnet 68 provided circumferentially on the outer peripheral portion, and penetrates the steered rod 50 on the inner peripheral side. And a generally cylindrical rotor 70. The rotor 70 has its outer peripheral portion held by bearings 72 and 74 provided on the inner peripheral portions of the housing members 60b and 60a, so that the rotor 70 can move relative to the housing 60 in the axial direction. Held impossible.
[0042]
The steered rod 50 is held by the housing 60 so as to be movable in the axial direction and non-rotatable by slidingly contacting and holding the rod holding portions 76a, 76b of the housing members 60b, 60c. Specifically, the steered rod 50 has a turning surface 78 formed as a flat surface in the shaft portion, and a part of the rod holding portion 76a is in sliding contact with the turning surface 78. The rotation of the steered rod 50 is prevented.
[0043]
A ball nut 80 having a bearing ball is provided on the inner peripheral portion of the rotor 70 so as not to rotate relative to the rotor 70 and to move in the axial direction. Further, a ball screw portion 82 in which a ball screw is formed is present at the central portion in the axial direction of the steered rod 50, and the ball nut 80 and the ball screw portion 82 are screwed together. When the turning motor 62 rotates, specifically, when the rotor 70 rotates, the ball nut 80 rotates and the turning rod 50 moves in the axial direction. In this steering apparatus, the steered rod 50 is moved by a full stroke when the steered motor 62 rotates about 30 times.
[0044]
The rotation angle of the steered motor 62, specifically, the rotation phase of the rotor 70 is detected by a motor rotation angle sensor 84. The motor rotation angle sensor 84 is mainly composed of a resolver and is provided between the rotor 70 and the housing member 60a so that the rotation phase of the rotor 70 within one rotation can be detected. The steered motor 62 is provided with a steered angle sensor 86 in the housing member 60b. The turning angle sensor 86 is also mainly composed of a resolver, and detects the rotational phase of the gear 90 that meshes with a worm 88 provided at one end of the rotor 70. The gear ratio is set so that the full stroke of the steered rod 50 corresponds to approximately one rotation of the gear 90. By detecting the rotational phase of the gear 90, the moving position of the steered rod 50, that is, The turning angle of the corresponding turning wheel 58 is detected. Although not described in detail, the detection of the turning angle by the turning angle sensor 86 is normally performed once at the start of the vehicle (turning on the ignition switch) and simultaneously the rotation angle of the turning motor 62 corresponding to the position. Is detected by the motor rotation angle sensor 84 and the two are associated with each other, the steering control based on the rotation angle detected by the motor rotation angle sensor 84 is performed. Although two motor rotation angle sensors 84 are provided, usually one of them functions, and when one of them malfunctions, the other is made a multiplex system so that the other functions. Yes. Redundancy considering so-called fail-safe.
[0045]
When the steered rod 50 is moved in the axial direction (left-right direction) by the rod driving device 52, the steered wheel 58 is steered to a steered angle corresponding to the moving position. The tie rod 54 is provided with an axial force sensor 92 (see FIG. 1) for detecting an axial force acting in the axial direction. The tie rod axial force measured by the axial force sensor 92 changes according to the reaction force that the steered wheel 58 receives from the road surface by steering, and is used for control of the operation reaction force applying device 24. Note that the configuration of the steering unit 12 is not limited to the above-described configuration, and it is possible to employ already-known various types of steering units provided with other types of actuators, sensors, and the like in this steering device. it can.
[0046]
The present steering apparatus is controlled by a steering ECU 14 having a computer 100 as a main component. The computer 100 includes a CPU 102, a ROM 104, a RAM 106, an input / output interface (I / O) 108, a bus 110 that connects them, and the like. A reaction force motor 26 and a steering motor 62 are connected to the input / output interface 108 via respective drive circuits (drivers) 112 and 114, and the operation angle sensor 22, the motor rotation angle sensor 84, and the rolling motor 62. A steering angle sensor 86 and an axial force sensor 92 are connected. Each of the drive circuits 112 and 114 monitors a supply current to the reaction force motor 26 and the steering motor 62, that is, a load current, and each has a portion that serves as a load ammeter. .
[0047]
The steering control by the steering ECU 14 is performed as follows. When the operator operates the steering wheel 20 for steering, the operation angle is detected by the operation angle sensor 22, and the target turning angle of the steered wheels 68 is determined based on the detected operation angle. As described above, the actual moving position of the steered rod 50, that is, the steered angle, is detected by the motor rotational angle sensor 84 in association with the rotational angle of the steered motor 62. Based on the deviation between the actual turning angle and the target turning nucleus, a current having a magnitude corresponding to the deviation is supplied to the turning motor 62. On the other hand, the reaction force received by the steered wheels 48 from the road surface during steering is the axial force received by the tie rod 54 detected by the axial force sensor 92 and the load current of the steered motor 62 monitored by the drive circuit 114. On the basis of the model stored in the ROM 104. The reaction force motor 26 is controlled based on the determined reaction force, and an operation reaction force corresponding to the reaction force received from the road surface is applied to the steering wheel 20.
[0048]
ii) Abnormal steering
In this steering apparatus, a case where the operator operates the steering wheel 20 to perform one steering (operation to turn the steering wheel) will be considered. As a rough rule, if the steering wheel 20 is operated at a constant operation speed in the middle of the operation, the rotation speed of the rotor 70 of the steering motor 62 (more precisely, (Rotational angular velocity) shows a substantially constant value or changes gradually. Here, for example, if it is assumed that foreign matter is caught in the bearing 72 or the bearing 74, or the bearing ball is rusted or chipped, the rotor 70 is prevented from rotating smoothly, and the rotational speed ( The rotational speed of the rotor 70 varies. Although this variation varies depending on the cause and the like, for example, in the initial stage of abnormality, the variation continues irregularly or becomes a periodic variation. In that case, the load current of the steered motor 62 and the rotational torque of the steered motor 62 (rotational torque of the rotor 70) also vary in the same manner.
[0049]
FIG. 3 shows an example of a single fluctuation of those physical factor values caused by the abnormality of the steered portion 12. These one-time fluctuations occur in a relatively small range ψ as a single rotation of the rotation angle of the motor, and the one-time fluctuation occurs once or plural times during one rotation of the steering motor 62. It is likely to occur continuously or frequently while the turning motor 62 is rotating. It should be noted that the fluctuation when the abnormality is in a relatively early stage has a small amplitude, but generally, as the degree of abnormality increases, the amplitude of the fluctuation increases.
[0050]
In addition to being caused by the abnormality of the steered portion 12, the physical factor values vary. For example, not only when the steering wheel 20 is suddenly operated, but also when the steered wheel 48 passes through a large unevenness on the road surface, it fluctuates due to the influence of the reaction force from the road surface. However, since the fluctuation in such a case occurs irregularly and does not continue for a long time, it can be distinguished from the fluctuation caused by the abnormality of the steered portion 12.
[0051]
Next, the abnormal fluctuation of the physical factor value due to another cause among the abnormalities of the steering unit 12 will be considered. For example, there is a case where there is a scratch in one place of the ball screw portion 82, or a case where there is a scratch in a portion of the steered rod 50 that is in sliding contact with the rod holding portion 76a or 76b. In such a case, when the steered rod 50 is moved in the axial direction and screwed with the ball nut 80 at the point of the scratch, or when it slides into contact with the rod holding portion 76a or 76b at the point of the scratch. In addition, the scratches hinder smooth movement of the steered rod 50. Also in this case, as in the case of the above-mentioned cause, the above parameters cause abnormal fluctuations. The abnormal fluctuation due to such a cause is characterized in that it occurs when the steered wheel 58 has a specific steered angle. From this, it is possible to distinguish such abnormal fluctuations from the above-mentioned sudden operation of the steering wheel 20 and abnormal fluctuations caused by large irregularities on the road surface.
[0052]
Various causes other than those described above are conceivable as the cause of the abnormality of the steered portion 12, and the physical factor values that vary due to the abnormality, that is, the parameters for detecting the abnormality are described above. Various things can be considered in addition to the above. In the present embodiment, in order to simplify the description, the abnormal fluctuation caused by the abnormality described above is targeted, the rotational speed (rotational angular speed) of the steered motor 62 is detected as the parameter, and the abnormal fluctuation of the rotational speed is detected. Based on the state, the abnormality of the steered portion 12 is authorized. If the foreign matter bites, the scratches on the steered rod 50, etc., are left as they are, they cause other damage, the abnormalities of the steered portion 12 worsen, and eventually it becomes impossible to steer. Conceivable. Considering such a point, it is desirable to detect the abnormality of the steered portion 12 at an early stage.
[0053]
iii) Detection of abnormalities in the steering section
Detection of the abnormality of the steered portion 12 is performed by the steering ECU 14 executing an abnormality detection program (abnormality detection routine) stored in the ROM 104. FIG. 4 shows a flowchart of the abnormality detection program. Hereinafter, a method for detecting an abnormality in the steered portion 12 will be described with reference to this flowchart. Note that this program is executed in a time-sharing manner with the turning control program during execution of the normal steering turning control program described above.
[0054]
When the vehicle is started, that is, when the ignition switch is turned on, initial setting processing from Step 1 (hereinafter abbreviated as “S1”, the same applies to other steps) to S3 is performed. First, in S1, the turning angle at the start is set. Specifically, the turning angle sensor 86 detects the turning angle at the time of start-up, corresponds to the motor rotation angle detected by the motor rotation angle sensor 84, and prepares for detecting an abnormality based on the motor rotation angle. Is called.
[0055]
In subsequent S2, a detection section is set. In the present embodiment, the variation state of the rotational speed of the steering motor 62 is detected over the entire region of the steering, and the set rotation angle that is the detection span of one variation state detection is the steering motor. The rotation angle (360 °) corresponding to one rotation of 62 is set. Therefore, a process of assigning one rotation of the turning motor 62 over the entire turning angle is performed. By this processing, one detection is always started at a constant rotation phase of the steering motor 62, and one detection is ended when one rotation is reached and the phase is reached. That is, in the turning angle scale, a detection pitch and detection span detection section corresponding to one rotation of the turning motor 62 is set. It should be noted that the detection start point and the detection end point are reversed in the detection of the same detection section in the operation at the right turn and the operation at the left turn.
[0056]
Next, in S3, an abnormal times storage area is set in a predetermined area of the RAM 106. In the abnormal times storage area, a result of recognition as to whether or not the fluctuation state of the rotational speed detected in one detection is an abnormal state, that is, whether or not the detected times are abnormal times is stored. FIG. 5 conceptually shows the abnormal times storage area. Two types of abnormal times storage area 120 are set. One type is a constant storage area 122, and each time detection is performed in this area, an authorization result indicating whether or not the detection time is an abnormal time is stored. Another type of area is the specific position storage area 124, and a plurality of such areas are set for each of the set detection sections. Each of the specific position storage areas 124 indicates whether or not the detection times are abnormal times each time detection is performed at the specific rotation angle position of the steering motor 62 associated with the turning angle. The certification result is stored. The constant storage area 122 has a size capable of storing the certification results for 50 detection times, and each of the specific position storage areas 124 has a size capable of storing the certification results for 25 detection times, and these areas have a first-in first-out memory. Each of them is stored in order from the latest certification result. After completing the initial setting process of S1 to S3, the detection of the fluctuation state and the preparation for the abnormality recognition process are completed.
[0057]
Subsequently, in S4, it is determined whether or not the steering device is being operated. This determination is made based on whether or not the detected value of the operation angle of the steering wheel 20 by the operation angle sensor 26 has changed by a predetermined value or more. If the operation is in progress, the detection of the variation state and the abnormality recognition process from S5 will be started. When turning is started and the set detection section is reached, that is, when the rotation phase of the turning motor 62 reaches the set start phase, detection of the fluctuation state is started. First, in S5, it is determined which detection section is the current detection, that is, which rotation angle position of the turning motor 62 is associated with the turning angle.
[0058]
In subsequent S6, one detection is performed. Within one rotation of the steering motor 62, a plurality of rotational speed measurement points are allocated and provided at a predetermined angular pitch (for example, 36 points in 10 ° increments, 12 points in 30 ° increments, etc.). ing. In the detection of the fluctuation state, the rotational speed of the steered motor 62 at all these measurement points is measured. The value of the rotational speed is obtained by dividing the value of the angular pitch of the measurement point by the time taken to rotate from the previous measurement point to the current measurement point. After the turning of the steering motor 62 and the measurement at all measurement points is completed, the maximum value ω of each measurement value _max And the minimum value ω _min Are determined, and a difference Δω between them is obtained. In this embodiment, this value Δω is used as a fluctuation state value indicating a fluctuation state of the rotation speed in one detection. That is, in this embodiment, the fluctuation state is detected by obtaining the rotational speed difference Δω within the detection section.
[0059]
Next, in S7, the detected rotational speed difference Δω is set to a set value Δω. ₀ It is determined whether or not the value exceeds. Δω ₀ Has a meaning as a value representing a threshold state for classifying whether the fluctuation state is an abnormal state or a normal state. As a result of the determination, the detected rotational speed difference Δω is the threshold Δω ₀ Is not exceeded, it is recognized that the detected time is not an abnormal time, and in S8, the value of the abnormal time flag F indicating whether or not it is an abnormal time is determined to be 0. The detected rotational speed difference Δω is the threshold value Δω ₀ Is exceeded, it is recognized as an abnormal time, and the abnormal time flag value F is determined to be 1 in S9.
[0060]
Next, in S <b> 10, the determined abnormal times flag value F is stored in the constant storage area 122 of the set abnormal times storage area 120. Next, in S11, the determined abnormal flag value F is stored in the specific position storage area 124 corresponding to the detection section in which the current detection is performed. As a result of the storage process in S10, the data stored in the constant storage area 122 is data that represents the appearance state of the abnormal times at all times, that is, the abnormal times at all rotation angle positions that do not depend on the turning angle. . Similarly, the data stored in the specific position storage area 124 is data representing a specific position abnormal turn, that is, an appearance state of an abnormal turn at a specific rotation angle position depending on the turning angle. In the initial setting, all values of the constant storage area 122 and the specific position storage area 124 are set to 0.
[0061]
Subsequently, a process for recognizing a normal abnormality, that is, an abnormality independent of the turning angle is performed. First, in S12, based on the data stored in the constant storage area 122, an abnormal times continuous count value C indicating how many times the abnormal times have continued from the current detection is calculated, and the value is set. Threshold number C ₀ It is determined whether (for example, 10 times) has been exceeded. As a result of determination, threshold number C ₀ Is exceeded, it is recognized in S13 that the steered portion 12 is always abnormal. The authorization result is displayed on the instrument panel of the vehicle, and the operator is notified of the normal abnormality of the steered portion 12. In S12, the abnormal number of consecutive times C is the threshold number C. ₀ Or after the process of S13, the process proceeds to the next S14. In S14, the percentage of abnormal times included in the data stored in the constant storage area 122, that is, the abnormal frequency appearance frequency R is calculated, and the threshold frequency R for which the value is set is calculated. ₀ It is determined whether or not (for example, 50%) is exceeded. As a result of determination, threshold frequency R ₀ Is exceeded, in S15, as in S13, it is recognized that the steering unit 12 is always abnormal. The certification result is similarly displayed on the instrument panel of the vehicle, and the steering unit Twelve abnormalities are notified to the operator. In S14, the abnormal frequency R is the threshold frequency R ₀ If it does not exceed, or after performing the process of S15, the process proceeds to a process for authorizing the specific position abnormality.
[0062]
In the process for authorizing the specific position abnormality, that is, the abnormality depending on the turning angle, first, in S16, based on the data stored in the specific position storage area 124 corresponding to the detection section in which the current detection is performed, The number of consecutive abnormal times C that indicates how many times abnormal times are continuous at the specific angle position from the detection. _x Is calculated and its value is set to the threshold number C _x0 It is determined whether (for example, 5 times) has been exceeded. As a result of determination, threshold number C ₀ Is exceeded, it is recognized in S17 that the steered portion 12 is abnormal at the specific rotation angle position. The authorization result is displayed on the instrument panel of the vehicle together with the specific rotation angle position, and the operator is notified of the specific position abnormality of the steered portion 12. In S16, the abnormal times continuous count value C _x Is the threshold number C _x0 Or after the process of S17 is performed, the process proceeds to the next S18. In S18, the ratio of abnormal times included in the data stored in the specific position storage area 124, that is, the abnormal frequency appearance frequency R _x Is calculated and its value is set to the threshold frequency R _x0 It is determined whether or not (for example, 50%) is exceeded. As a result of determination, threshold frequency R _x0 Is exceeded, it is recognized in S19 that the steered portion 12 is abnormal at the specific rotational angle position as in S17. Similarly, the authorization result is displayed on the instrument panel of the vehicle together with the specific rotation angle position, and the operator is notified of the specific position abnormality of the steered portion 12. Abnormal frequency of appearance R in S18 _x Is the threshold frequency R _x0 Or after the process of S19 is performed, the process returns to S4, and if the steering wheel 20 is being operated, the above-described series of processes is repeated, and in the next detection section, the detection of the fluctuation state and the abnormality are detected. The certification process is performed. In this way, while the vehicle is operating, that is, while the ignition switch is ON, the detection and authorization processes are repeated, and an abnormality in the steered portion 12 is detected.
[0063]
In this program, the above detection is continuously performed while the steering wheel 20 is being operated. Although not shown in the flowchart, when one operation of the steering wheel 20 is completed, if it is in the middle of the detection section, that is, in the middle of one detection, the operation for a predetermined time is thereafter performed. When it is not performed, the detection at that time is aborted, and it is determined that there was no detection at that time. Also, when the steering wheel 20 is reversely operated in the middle of one detection, the detection at that time is aborted, and a new detection / authorization process is performed with the reverse operation as one operation. ing.
[0064]
The above processing is performed by an abnormality detection device included in the steering device. The abnormality detection device is essentially a motor rotation angle sensor mainly using a portion of the steering ECU 14 that executes the abnormality detection program. 84, etc. are comprised. Although the abnormality detection device is configured to include a variation detection unit and an abnormality recognition unit, the variation detection unit is configured to include a portion of the steering ECU 14 that executes the processes of S4 to S6 of the program, The abnormality recognition unit is configured to include a part that executes the processes of S7 to S18. The processes in the variation detection unit and the abnormality recognition unit are the parts responsible for the variation detection step and the abnormality recognition step in the abnormality detection method, respectively. The process of S4 to S6 is a process of detecting a plurality of times continuously in a single operation of the steering wheel 20, and a process of detecting a plurality of times at a specific rotation angle position. Therefore, it can be said that the fluctuation detection unit includes a continuous detection unit and a specific angular position detection unit. Moreover, since the fluctuation | variation of the rotational speed of the steering motor 62 is detected, it can be said that a fluctuation | variation detection part contains a rotational speed fluctuation | variation detection part. Furthermore, the process of S7-S11 is a process which performs the recognition of abnormal times for each performed detection, and the process of S12-S19 performs the recognition of abnormalities based on the appearance state of abnormal times. Since it is a process to be performed, it can be said that the abnormality recognition unit is configured to include an abnormal times recognition unit and an abnormal times appearance state-based authentication unit. More specifically, the abnormal times appearance state-based authorization unit includes an abnormal times continuous time certification unit as a part for executing the processes of S12, S13, S16, and S17, and executes the processes of S14, S15, S18, and S19. It can be said that it includes the frequency-based certification department as a part to do. Further, according to the above program, data relating to the abnormal times at the specific angular positions certified in S7 to S9 is stored in a predetermined storage area in S11, and abnormal certification in the specific angular positions is based on the data in S16 to S19. It is carried out. Therefore, in other words, it can be said that the specific angle position recognition unit is configured to include a part for executing those steps.
[0065]
In the above-described abnormality detection, the abnormality is recognized based on the fluctuation state of the rotational speed of the steering motor 62, but instead of this aspect, the abnormality is detected based on the fluctuation state of the load current of the steering motor 62. Certification can also be performed. As described above, since the drive circuit 114 monitors the current supplied to the steered motor 62, the drive circuit 114 detects the variation state of the monitored current value and performs the authorization based on the variation state. As described above, the program may be changed. Specifically, for example, in S6, the maximum value I of the load current in the detection section _max And the minimum value I _min A difference ΔI is detected, and in S7, ΔI is a threshold value ΔI. ₀ The determination may be made based on whether or not the value is exceeded. Thus, when utilizing the load current of the steering motor 62, the said fluctuation | variation detection part functions as a load fluctuation | variation detection part.
[0066]
In the above embodiment, the cause of the abnormality of the steered portion 12 is typical to some extent. As described above, depending on the cause of abnormality, the state of fluctuation of the physical factor value as the parameter may be different. In that case, the set rotation angle, which is a detection span, and each threshold value Δω ₀ , C ₀ , R ₀ , C _x0 , R _x0 Or the number of abnormal times flag value F that can be stored in the abnormal times storage area is appropriately changed to a value according to the intended cause, etc. It is sufficient to execute the process.
[0067]
Second Embodiment
i) Overall structure of the steering system
FIG. 6 schematically shows the overall configuration of another vehicle steering apparatus including an abnormality detection apparatus as an embodiment of the present invention. The present steering device is a so-called normal power steering device that steers a wheel by the operation force of a steering wheel assisted by an electric motor and the assisted driving force. The steering device is roughly configured to include an operation unit 10, a steering unit 12, and a steering ECU 14. Note that in the description of the present embodiment, the same reference numerals as those used earlier are used for the same functions as those of the previous embodiment.
[0068]
The operation unit 10 includes a steering wheel 20 and a steering column 150 connected thereto. The operating force applied to the steering wheel 20 is transmitted as the rotational driving force of the steering column 150 and input to the steered portion 12.
[0069]
The steered portion 12 includes a rod driving device 52 that functions as an actuator for steering and moves the steered rod 50 in the vehicle width direction, and each end of the steered rod 50 has a tie rod 54 and a knuckle arm 56. And connected to each of the left and right steered wheels 58.
[0070]
FIG. 7 shows the rod driving device 52. FIG. 7A is a view from above, and FIG. 7B is a cross-sectional view. The rod driving device 52 includes a housing 60 that includes three housing members 60a, 60b, and 60c, and a steering motor 62 that is an electric motor as a drive source therein. The steered motor 62 includes a stator 66 including a coil 64 circumferentially provided on the inner surface of a housing member 60a having a substantially cylindrical shape, a magnet 68 provided circumferentially on the outer peripheral portion, and penetrates the steered rod 50 on the inner peripheral side. And a generally cylindrical rotor 70. The rotor 70 has its outer peripheral portion held by bearings 72 and 74 provided on the inner peripheral portions of the housing members 60b and 60a, so that the rotor 70 can move relative to the housing 60 in the axial direction. Held impossible.
[0071]
The steered rod 50 can be called a rack bar, and has a rack portion 152 formed with a rack at an intermediate portion thereof. The steered rod 50 has a ball screw portion 82 in which a ball screw is formed at a position aligned with the rack portion 152. A pinion 154 meshes with the rack portion 152, and the pinion 154 is connected to the steering column 150 and is rotated by the rotation of the steering column 154. The steered rod 50 is in sliding contact with the rod holding portion 76b of the housing member 60c, and is in sliding contact with another rod support portion 156 provided at a portion where the pinion 154 of the housing member 60b is present, and is held by them. Thus, the housing 60 is held so as to be movable in the axial direction and non-rotatable. Specifically, the steered rod 50 has a turning surface 78 formed as a flat surface on the shaft portion, and a part of the rod holding portion 76b is in sliding contact with the turning surface 78. The rotation of the steered rod 50 is prevented. Further, a ball nut 80 having a bearing ball is provided on the inner peripheral portion of the rotor 70 so as not to be rotatable relative to the rotor 70 and not relatively movable in the axial direction. The ball nut 80 includes a ball screw portion. The ball screw formed at 82 is screwed.
[0072]
The pinion 154 is rotated by the operating force of the steering wheel 20 and the steered rod 50 is moved in the axial direction by the rotational driving force. Further, if the steering motor 62 rotates, specifically, if the rotor 70 rotates, the ball nut 80 rotates and the steered rod 50 moves in the axial direction. In other words, the rod driving device 52 has a structure in which the steered wheel 58 is steered by moving the steered rod 50 in the axial direction by the operation force of the steering wheel 20 and the rotational drive force of the steered motor 62. In addition, since the steering motor 62 assists the operating force of the steering wheel 20 in the steering rod 50 in which the rack is formed, the steering device is a rack assist type power steering device. It is.
[0073]
Further, the rod driving device 52 includes a torque sensor 158 at a connection portion between the shaft of the pinion 154 and the steering column 150. The torque sensor 158 detects the rotational torque generated between the shaft of the pinion 154 and the steering column 150 using the torsion bar torsion, and is generally used. Is omitted. Based on the rotational torque value detected by the torque sensor 158, the assist force of the steering motor 62 is determined. Further, the rod drive device 52 includes a motor rotation angle sensor 84 for detecting the rotation angle of the steering motor 62, specifically, the rotation phase of the rotor 70. The motor rotation sensor 84 is mainly composed of a resolver, and is provided between the rotor 70 and the housing member 60a so that the rotation phase of the rotor 70 within one rotation can be detected. Note that the configuration of the steering unit 12 is not limited to the above-described configuration, and it is possible to employ already-known various types of steering units provided with other types of actuators, sensors, and the like in this steering device. it can.
[0074]
The present steering apparatus is controlled by a steering ECU 14 having a computer 100 as a main component. The computer 100 includes a CPU 102, a ROM 104, a RAM 106, an input / output interface (I / O) 108, a bus 110 that connects them, and the like. A steering motor 62 is connected to the input / output interface 108 via a drive circuit 114, and a motor rotation angle sensor 84 and a torque sensor 158 are connected. The drive circuit 114 monitors the supply current to the steered motor 62, that is, the load current, and has a portion serving as a load ammeter.
[0075]
The steering control by the steering ECU 14 is performed as follows. When the operator operates the steering wheel 20 for steering, turning is started. In the turning, a rotational torque is generated between the shaft of the pinion 154 and the steering column 150 as described above. The rotational torque is detected by the torque sensor 158, and the assist force of the steered motor 62 is determined according to the rotational torque. Then, a current having a magnitude corresponding to the assist force is supplied to the steering motor 62.
[0076]
ii) Abnormal steering
Also in this embodiment, the abnormality of the steered part 12 with the same cause as in the previous embodiment occurs. Further, in the present embodiment, an abnormality caused by the biting of foreign matter, a flaw, or the like can also occur at the meshing position between the rack portion 152 and the pinion 154. Since the state of the abnormal fluctuation of the physical factor value is the same as that described above, the description thereof is omitted here.
[0077]
The pinion 154 that meshes with the rack portion 152 of the steered rod 50 is a drive rotating body that is provided in the steered portion 12 and is driven to rotate by itself. It appears not only in the abnormal fluctuation of the factor value but also in the abnormal fluctuation of the physical factor value of the pinion 154. Therefore, in this embodiment, unlike the previous embodiment, the rotational torque generated in the pinion 154 detected by the torque sensor 158 is adopted as a parameter for abnormality detection, and this abnormal variation is detected to detect the turning unit 12. It is assumed that an abnormality is detected. In addition, since the variation detection span is a section corresponding to one rotation of the steered motor 62 as in the previous embodiment, the variation state in the section is a variation within one rotation of the rotational torque of the steered motor 62. In other words, this embodiment can be said to indirectly detect fluctuations in the rotational torque of the steered motor 62.
[0078]
iii) Detection of abnormalities in the steering section
Detection of an abnormality in the steered portion 12 is performed by the steering ECU executing an abnormality detection program, as in the previous embodiment. Since the program is similar to the program shown in the flowchart in FIG. 4, it will be described with reference to the flowchart. In addition, description of steps for performing almost the same processing is omitted.
[0079]
First, S1 in the initial setting process is not executed in the present embodiment. This is because the present steering device is a power steering device and therefore does not include a means for detecting the turning angle, and control based on the turning angle is not performed. In the detection section setting in S <b> 2, first, the rotational phase of the steered motor 62 at the time when the ignition switch is turned on is detected by the motor rotation angle sensor 84. The set rotation angle is set to 360 °, and a plurality of detection sections in which one rotation of the steering motor 62 is one detection section are set on the basis of the detected rotation phase. In the present steering device, the turning angle of the steered wheels 58 cannot be recognized, and therefore, the number of detections corresponding to the entire stroke of the steering is detected in each of the left and right turning directions around the current rotation angle position. A section is set. It cannot be specified at which turning angle each of these detection sections, but these detection sections are relatively associated with the turning angle. In S3, an abnormal times storage area 120 as shown in FIG. 5 is also set in this embodiment. Although the number of specific position storage areas 124 is set according to the number of detection sections, in the present embodiment, some of these areas are not used.
[0080]
In the variation detection process of S4 to S6, the physical factor value that is the target of detection of the variation state is different from the previous embodiment, and the others are hardly different. In the present embodiment, in S6, the torque value is measured by the torque sensor 158 at each of the aforementioned measurement points, and the maximum value T of the measured value of the rotational torque in the detection section is measured. _max And the minimum value T _min Are determined, and their torque difference ΔT is determined. Also in the abnormality recognition process of S7 to S19, the torque difference ΔT is the threshold ΔT in S7. ₀ It is only different from the previous embodiment that the approval of whether or not is exceeded, and the others are hardly different.
[0081]
As described above, also in the power steering apparatus, according to the present invention, it is possible to detect an abnormality of the steered portion 12 at an early stage. In the present embodiment, the fluctuation state of the rotational torque of the pinion 154 that is the driving rotary body (indirectly, the fluctuation state of the rotational torque of the steering motor 62) is detected, and the processing of S4 to S6 of the steering ECU 14 is performed. The rotational torque fluctuation detecting unit is configured to include a part for executing the above. In the case of the present embodiment as well, as in the previous embodiment, the abnormality can be recognized based on the fluctuation state of the load current of the steered motor 62, and the motor rotation angle sensor 84 is used. It is also possible to measure the rotational speed of the steered motor 62 and identify an abnormality based on the fluctuation state of the rotational speed. Further, similarly to the previous embodiment, it is possible to change the set rotation angle, each threshold value, and the like as appropriate according to the cause of the target abnormality, and to perform the process of detecting the fluctuation state and identifying the abnormality.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of an operation unit / steering unit separation type steering apparatus configured to include an abnormality detection apparatus of the present invention.
FIG. 2 is a cross-sectional view showing a steered rod driving device that constitutes an operation unit / steering unit separation type steering device;
FIG. 3 is a graph illustrating fluctuations in the rotation speed of a steered motor caused by an abnormality in the steered portion.
FIG. 4 is a flowchart of an abnormality detection program executed in the abnormality detection device of the present embodiment.
FIG. 5 is a diagram conceptually showing an abnormal times storage area set in a RAM of a steering ECU.
FIG. 6 is a schematic diagram showing an overall configuration of a power steering device configured to include the abnormality detection device of the present invention.
FIG. 7 is a diagram and a cross-sectional view of a steered rod drive device that constitutes a power steering device as viewed from above.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10: Operation part 12: Steering part 14: Steering electronic control unit (abnormality detection apparatus) 20: Steering wheel (operation member) 50: Steering rod 52: Rod drive device 58: Steering wheel 60: Steering motor (drive) Motor) 84: Motor rotation angle sensor 86: Steering angle sensor 114: Drive circuit (load ammeter) 120: Abnormal rotation storage area 122: Constant storage area 124: Specific position storage area 152: Rack part 154: Pinion 158: Torque Sensor

Claims (7)

(a) An operation unit having an operation member operated by a driver for steering, and (b) a drive motor, which is driven by the rotational driving force of the motor or assisted by the rotational driving force of the motor. An apparatus for detecting an abnormality of the steered portion of a vehicle steering device including a steered portion that is driven by a driving force from the operating portion and steers a wheel according to an operation of the operating member. ,
The drive motor or rotational drive having a physical factor value that directly or indirectly indicates the rotational state of the rotational drive body that is present in the transmission path of the rotational drive force of the drive motor or the drive motor and is rotationally driven by itself. A fluctuation detector for detecting a fluctuation state within a set rotation angle of the body ;
A steering device abnormality detection device comprising: an abnormality recognition unit that recognizes that the steering unit is abnormal based on the detected fluctuation state. The fluctuation detecting unit is
(A) as a fluctuation state of the physical factor value, a rotational speed fluctuation detection unit that detects a fluctuation state of the rotational speed of the drive motor or the rotary drive body;
(B) as a fluctuation state of the physical factor value, a rotational torque fluctuation detection unit for detecting a fluctuation state of the rotational torque of the drive motor or the rotary drive body;
2. The steering apparatus abnormality detection device according to claim 1, further comprising: (C) at least one selected from a load fluctuation detection unit that detects a fluctuation state of a load of the drive motor as the fluctuation state of the physical factor value.   The steering apparatus abnormality detection device according to claim 1 or 2, wherein the set rotation angle is an angle corresponding to one rotation of the drive motor or the drive rotator.   The fluctuation detection unit performs one-time detection of the fluctuation state of the physical factor value within the set rotation angle in accordance with a predetermined condition, and the abnormality recognition unit When the fluctuation state detected in the one-time detection exceeds a set threshold state, the abnormal time recognition unit that recognizes the time as an abnormal time, and the turning unit based on the appearance state of the abnormal time The steering device abnormality detection device according to any one of claims 1 to 3, further comprising: an abnormal times appearance state dependency recognition unit that recognizes an abnormality. The abnormal times appearance state dependence certification part,
(B) a frequency-based authorization unit that authorizes the steering unit to be abnormal when the frequency of occurrence of the abnormal times exceeds a set threshold frequency;
(B) The steering according to claim 4, further comprising at least one of an abnormal times continuous time recognition unit that recognizes that the steering unit is abnormal when the abnormal times continue beyond a set threshold number of times. Device abnormality detection device. The rotational angle position of the drive motor or drive rotor is associated with the turning angle of the wheel,
The said abnormality recognition part is provided with the specific angle position recognition part which performs the recognition of the said abnormal times and recognizes the said abnormality about the specific rotation angle position corresponding to a specific turning angle. The steering apparatus abnormality detection apparatus of description. (a) An operation unit having an operation member operated by a driver for steering, and (b) a drive motor, which is driven by the rotational driving force of the motor or assisted by the rotational driving force of the motor. A steering unit for a vehicle including a steering unit that is driven by a driving force from the operation unit and steers a wheel in response to an operation of the operation member. ,
The drive motor or rotational drive having a physical factor value that directly or indirectly indicates the rotational state of the rotational drive body that is present in the transmission path of the rotational drive force of the drive motor or the drive motor and is rotationally driven by itself. A variation detection step of detecting a variation state within a set rotation angle of the body ;
And an abnormality recognition step of determining that the steered portion is abnormal based on the detected fluctuation state.

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