Anomaly detection device

Abstract

To make it possible to detect presence or absence of an abnormality in a speed reducer in the case where an electric actuator includes the speed reducer.SOLUTION: When a speed reducer in an electric actuator is abnormal, actuation efficiency is degraded. Therefore, for example, when a control target value for the electric actuator remains unchanged, an actual current value to be supplied actually to the electric actuator or an integrated value of the actual current value over a set period of time gets larger. Otherwise, the actual current value may get larger for a standard relation between the control target value and the actual current value. Therefore, presence or absence of an abnormality in at least one speed reducer of plural electric actuators can be detected based on the control target values and the actual current value in the plural electric actuators having the speed reducers.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an abnormality detection device that detects whether or not an abnormality exists in an electric actuator. [Background technology]

[0002] Patent Document 1 describes a steering system that includes steering actuators provided on each of the left and right rear wheels of a vehicle, steering angle sensors that detect the steering angles of each of the left and right rear wheels, and a control device that controls each of the steering actuators based on the detection values ​​of each of the steering angle sensors. The steering system described in Patent Document 1 is provided with two steering angle sensors that detect the steering angles of each of the left and right rear wheels. Therefore, even if one of the steering angle sensors is abnormal, the respective steering actuators can be controlled based on the detection value of the other steering angle sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-223868 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to make it possible to detect whether or not there is an abnormality in a reducer when the electric actuator includes the reducer. [Means for solving the problem]

[0005] In an electric actuator, if the reducer is malfunctioning, the operating efficiency decreases. Therefore, for example, when the control target value for the electric actuator is the same, the actual current value actually supplied to the electric actuator or the integrated value of the actual current value over a set time increases. Furthermore, the actual current value may increase relative to the standard relationship between the control target value and the actual current value. Based on the above, it is possible to detect whether or not there is an abnormality in the reducer of at least one of multiple electric actuators equipped with a reducer, based on the control target value and actual current value for each of the multiple electric actuators. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a diagram conceptually showing an entire steering system equipped with an abnormality detection device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view showing a wheel steering device which is a component of the steering system. [Figure 3] FIG. 2 is a front view of an electric actuator that is a component of the wheel steering device. [Figure 4] FIG. 2 is a cross-sectional view of a reducer that is a component of the electric actuator. [Figure 5] 3A to 3C are diagrams conceptually illustrating the operation of the reducer. [Figure 6] 6 is a flowchart showing an abnormality detection program stored in a storage unit of the steering ECU of the steering system. [Figure 7] FIG. 4 is a diagram showing the relationship between the target steering angle and the actual current value in each of the wheel steering devices provided on the left and right front wheels of the steering system. [Figure 8] 8A and 8B are diagrams showing the relationship between the target steering angle and the actual current value in each of the wheel steering devices in another state. DETAILED DESCRIPTION OF THE INVENTION

[0007] A wheel steering system (hereinafter, sometimes simply referred to as a steering system) provided in a vehicle equipped with an abnormality detection device as one embodiment for carrying out the present invention will be described in detail below with reference to the drawings. [Example]

[0008] As shown in Figure 1, this steering system includes wheel steering devices (hereinafter sometimes simply referred to as steering devices) 12FL, 12FR provided respectively for left and right front wheels 10FL, 10FR which are the steered wheels of the vehicle, a steering operation device 14 through which the driver performs steering operation, a steering ECU 16 mainly consisting of a computer, etc. Hereinafter, the symbols FL, FR, etc. which indicate the positions of the wheels may be omitted when it is not necessary to specify the positions of the wheels or when referring to them collectively, etc.

[0009] As shown in Fig. 2, the front wheel 10 is rotatably held by a steering knuckle (hereinafter referred to as the knuckle) 17. A lower arm 18 is connected to the knuckle 17, and the lower arm 18 is connected to a vehicle body member (not shown) via a bush so as to be swingable in the vertical direction (around an axis extending in the front-to-rear direction). The knuckle 17 is supported by the vehicle body member (not shown) via a shock absorber 20, a suspension spring 21, etc.

[0010] Each of the steering devices 12 includes the knuckle 17 described above, a steering actuator 24 as an electric actuator provided on the lower arm 18, a pitman arm 34 connected to the output shaft 24out (see Figures 3 and 4) of the steering actuator 24, and a tie rod 26 connecting the pitman arm 34 to the knuckle arm 22 of the knuckle 17.

[0011] As shown in FIG. 3, the steering actuator 24 includes a steering motor 30 which is an electric motor as a drive source, and a reducer 32 which reduces the speed of rotation of the steering motor 30 to increase the force. In this embodiment, the reducer 32 includes a strain wave gear device, which is a differential device that utilizes the differential between an ellipse and a perfect circle. An example of a strain wave gear device is Harmonic Drive (registered trademark). As shown in Fig. 4, the reducer 32 includes a wave generator 40, a flexible external gear (flexspline) 41, a rigid internal gear (circular spline) 42, etc.

[0012] The rigid internal gear 42 is generally cylindrical and has a plurality of internal teeth 42g on its inner circumferential surface. The rigid internal gear 42 is fixed to the main body 32h of the reducer 32. Wave generator 40 includes a generally elliptical, plate-like rigid cam plate 41b and a flexible bearing 40v provided on the outer periphery of rigid cam plate 41b. Output shaft 30out of steering motor 30, which is the input shaft of speed reducer 32, is attached to rigid cam plate 41b so as to be rotatable integrally with it. The inner ring of bearing 40v rotates integrally with rigid cam plate 41b.

[0013] Flexible external gear 41 is flexible and includes a cylindrical portion and a bottom portion which is a diaphragm. A plurality of external teeth 41g are provided on the outer peripheral surface of the cylindrical portion of flexible external gear 41. The output shaft of speed reducer 32, i.e., output shaft 24out of steering actuator 24, is attached to the bottom portion of flexible external gear 41 via thick portion 41h so as to be rotatable integrally therewith.

[0014] An outer ring of a bearing 40v of wave generator 40 is fitted onto the inner periphery of the cylindrical portion of flexible external gear 41, while flexible external gear 41 is disposed on the inner periphery of rigid internal gear 42. As shown in FIG. 5 , some of the external teeth 41g of flexible external gear 41 can mesh with some of the internal teeth 42g of rigid internal gear 42. In this embodiment, the number of internal teeth 42g of rigid internal gear 42 is two more than the number of external teeth 41g of flexible external gear 41. Because wave generator 40 has an elliptical shape, the internal teeth 42g and external teeth 41g mesh with each other at two locations 180° apart in the circumferential direction. Therefore, when output shaft 30out of steering motor 30 (i.e., rigid cam plate 40b of wave generator 40 and inner ring of bearing 40v) rotates once, the meshing position between internal teeth 42g and external teeth 41g moves by two teeth. The flexible external gear 41 (and the outer ring of the bearing 40v) rotates in accordance with this movement of the meshing position, causing the output shaft 24out to rotate.

[0015] A pitman arm 34 is connected at one end to the output shaft of the reduction gear 32, which is the output shaft 24out of the steering actuator 24, so as to be rotatable integrally therewith. The other end of the pitman arm 34 is connected to one end of the tie rod 26 via a connecting portion 36. The other end of the tie rod 26 is connected to the knuckle arm 22 via a connecting portion 38.

[0016] In the present steering device 12, when steering actuator 24 is driven in the direction indicated by arrow X in Fig. 2, pitman arm 34 is rotated about the axis of steering actuator 24. As pitman arm 34 rotates, tie rod 26 is moved in the direction indicated by arrow Y, whereby knuckle arm 22 and knuckle 17 are rotated about kingpin axis KP, and wheel 10 is steered in the direction indicated by arrow Z.

[0017] As shown in FIG. 1, the steering operation device 14 includes a steering wheel 56 as a steering operation member that is operated by the driver, an operation angle sensor 58 that detects the operation angle, which is the rotation angle of the steering wheel 56, as the operation amount of the steering operation member, and a reaction force imparting device 60 that imparts an operation reaction force to the steering wheel 56.

[0018] The present steering system includes motor ECUs 70FL, 70FR, etc. in addition to steering ECU 16. Motor ECUs 70FL, 70FR are respectively provided corresponding to steering motors 30 of steering actuator 24. These steering ECU 16, motor ECU 70, etc. are connected to each other so that they can communicate with each other via a CAN (Control area network) 72. In addition to the steering ECU 16 and motor ECU 70, for example, a meter ECU 74, etc. are connected to CAN 72. An alarm device such as a display 76 is connected to meter ECU 74.

[0019] Steering ECU 16 includes an execution section, a storage section, input / output sections, etc., all of which are not shown, and to the input / output section are connected operation angle sensor 58, vehicle speed sensor 80 that detects the traveling speed of the vehicle, etc., as well as reaction force application device 60. In steering ECU 16, target steering angles MSTR_FL, MSTR_FR (one example of a control target value), which are target values ​​for the steering angles of each of left and right front wheels 10, are determined based on operation angle θ detected by operation angle sensor 58, traveling speed v of the vehicle, etc. Furthermore, reaction force application device 60 is controlled based on the determined target steering angles MSTR_FL, MSTR_FR, etc. Furthermore, the determined target steering angles MSTR_FL, MSTR_FR are supplied to motor ECUs 70FL, 70FR, respectively, via CAN 72. Note that target steering angles MSTR_FL, MSTR_FR may also be determined for the purpose of abnormality detection, regardless of steering angle θ, traveling speed v, etc., as will be described later.

[0020] Motor ECU 70 is similarly mainly composed of a computer including an execution section, a storage section, an input / output section, etc. Connected to the input / output section are steering angle sensor 84 which detects the steering angle of wheel 10, current sensor 86 which detects an actual current value (which can be referred to as a control current value or a supply current value) which is the value of a current actually supplied to steering motor 30, etc., and is also connected to steering motor 30, etc. Motor ECU 70 feedback-controls the current supplied to steering motor 30 so that the actual steering angle (which is an example of an actual operating value) which is the actual steering angle of wheel 10 detected by steering angle sensor 84 approaches the target steering angle supplied from steering ECU 16.

[0021] In the steering system configured as above, it is determined whether or not there is an abnormality (deterioration) in the reducer 32 of the steering actuator 24. As described above, the reducer 32 includes a strain wave gearing device, which provides a large reduction ratio and high inverse efficiency. However, when a large external force acts on the wheel 10, such as when the wheel 10 hits a curb, tooth misalignment (also referred to as tooth skipping) due to ratcheting may occur. That is, when a large external force acts on the wheel 10 and acts between the flexible external gear 41 and the rigid internal gear 42 via the tie rod 26 and the pitman arm 34, tooth misalignment may occur between the external teeth 41g of the flexible external gear 41 and the internal teeth 42g of the rigid internal gear 42. When tooth misalignment occurs, poor meshing occurs between the external teeth 41g of the flexible external gear 41 and the internal teeth 42g of the rigid internal gear 42, making it difficult for the rotation of the wave generator 40 to be smoothly transmitted to the rotation of the flexible external gear 41. This condition is referred to as a deterioration or abnormality of the reducer 32 equipped with a strain wave gearing device. When the reducer 32 deteriorates in this way, the efficiency of the reducer 32 deteriorates, and the actual current value for the target steering angle and the integrated value of the actual current value over a set time period increase.

[0022] Therefore, in this embodiment, when the target steering angles of left and right front wheels 10FL, 10FR are approximately the same (MSTR_FL≈MSTR_FR), integrated values ​​SI_FL, SI_FR over a set time of actual current values ​​I_FL, I_FR, which are current values ​​actually supplied to steering motors 30FL, 30FR in two steering actuators 24FL, 24FR as multiple electric actuators, are acquired. Then, when the ratio of one of these integrated values ​​SI_FL, SI_FR to the other is greater than a set ratio γx that is greater than 1, it is determined that reducer 32 of one of steering actuators 24 is abnormal or has deteriorated. Set ratio γx can be a value greater than 1 and less than 2, for example. SI_Fi / SI_Fj>γx (i=L,R j=R,L)

[0023] The abnormality detection (deterioration determination) program shown in the flowchart of FIG. In step 1 (hereinafter simply referred to as S1, and the same applies to the other steps), each variable is initialized. Specifically, the integrated current values ​​SI_FL, SI_FR, the deterioration determination permission flag Flag, and the count value JDT of the deterioration determination counter are set to 0 as their initial values. In S2, the operating angle θ, the vehicle speed sensor 80, and the current sensor 86 detect the operating angle θ, the traveling speed v, and the actual current values ​​I_FL, I_FR supplied to the motor 30.

[0024] In S3, target steering angles MSTR_FL, MSTR_FR for left and right front wheels 10Fl, 10FR are obtained based on the operating angle θ and traveling speed v. Then, in S4, it is determined whether the absolute values ​​of the target steering angles |MSTR_FL|, |MSTR_FR| are each greater than a set angle STR, which serves as a set value. Set angle STR can be set to a magnitude that enables estimation that wheels 10 have been steered and enables detection of the presence or absence of an abnormality in speed reducer 32. This is because, if the absolute value of the target steering angle is equal to or less than the set angle, a difference is unlikely to occur between the integrated values ​​of the actual currents supplied to the respective steering motors 30, even if there is an abnormality in speed reducer 32.

[0025] If the determination in S4 is YES, then in S5, the deterioration determination permission (abnormality detection permission) flag Flag is set to 1. If the determination is NO, the deterioration determination permission flag Flag remains 0. If the determination in S4 is YES, then deterioration determination of the reducer 32 is permitted.

[0026] In S6, it is determined whether the deterioration determination permission flag Flag is 1, and in S7, it is determined whether the target steering angles MSTR_FL, MSTR_FR are substantially the same. If the determinations in S6 and S7 are YES, then in S8 and S9, integrated values ​​SI_FL and SI_FR of actual current values ​​I_FL and I_FR supplied to steering motor 30 for a set time are obtained. S8 and S9 are repeatedly executed for the set time.

[0027] For example, as shown in Figure 7, if target steering angles MSTR_FL, MSTR_FR for left and right front wheels 10FL, 10FR are approximately the same and change as shown in Figure 7(a), the control current value (actual current value) supplied to steering motor 30FL of steering actuator 24FL for left front wheel 10FL and the control current value (actual current value) supplied to steering motor 30FL of steering actuator 24FR for right front wheel 10FR may change as shown in Figures 7(b) and 7(c), respectively. The control current value changes as the rotational speed of steering motor 30 accelerates or decelerates. Then, if the determination in S4 is YES at time ta and the determinations in S6 and S7 are YES, the control current values ​​are integrated from time ta until set time T has elapsed, and integrated values ​​(shaded areas in the figure) are obtained.

[0028] When the set time T has elapsed, the determination in S9 becomes YES, and in S10, it is determined whether the absolute value of the difference between these integrated values ​​SI_FL and SI_FR divided by the average value {(SI_FL+SI_FR) / 2} is greater than an abnormality determination ratio γ. The ratio γ can be set to, for example, a value greater than 0 and less than 1. |SI_FL-SI_FR| / {(SI_FL+SI_FR) / 2}>γ If the determination in S10 is NO, it is determined that reducers 32FL, 32FR of left and right steering actuators 24FL, 24FR are both normal, and integrated values ​​SI_FL, SI_FR are set to initial value 0 in S11.

[0029] On the other hand, if the determination in S10 is YES, then in S12 it is determined that one of the reducers 32FL, 32FR has deteriorated (is abnormal), and the count value JDT of the deterioration determination counter is incremented by 1. Also, the integrated values ​​SI_FL, SI_FR are set to 0. In S13, it is determined whether the count value JDT of the deterioration determination counter is greater than a set number of times n. If the number of deterioration determinations JDT is greater than the set number of times n, this is notified in S14. This is because if the deterioration determination is performed a number of times exceeding the set number of times n, there is a high possibility that the reducer 32 has truly deteriorated. For example, abnormality information (deterioration information) indicating that there is a high possibility that one of the speed reducers 32FL, 32FR is abnormal, or maintenance information indicating that replacement or maintenance of the speed reducers 32FL, 32FR is desirable, can be supplied to the meter ECU 74 via the CAN 72. The meter ECU 74 can notify the abnormality information or maintenance information via a notification device such as a display 76.

[0030] In this way, in this embodiment, it is possible to easily obtain whether or not there is an abnormality in either one of the speed reducers 32FL, 32FR. Furthermore, while the vehicle is running, the target steering angles for the left and right front wheels 10FL, 10FR are often approximately the same. Therefore, step S7 is not essential. In other words, the abnormality detection program can be executed in a running state in which the target steering angles MSTR_FL, MSTR_FR for the left and right front wheels 10FL, 10FR are approximately the same.

[0031] In the above embodiment, the case has been described in which the target steering angle is determined based on the vehicle's traveling speed v, operating angle θ, etc. when the vehicle is in a normal traveling state. However, when the vehicle is stopped, etc., the target steering angle can also be determined for the purpose of detecting an abnormality in speed reducer 32, without being based on the vehicle's traveling speed v or operating angle θ.

[0032] For example, as shown in Figure 8(a), when the vehicle is stopped, target steering angles MSTR_FL, MSTR_FR can be changed in a pulsed manner (the steering angle is changed between + and -, i.e., the steering direction is changed between right and left). In this case, as in the above embodiment, the presence or absence of an abnormality in at least one of reducers 32 of left and right steering actuators 24 is detected by comparing the integrated values ​​of the actual current values ​​of steering motors 30. Note that the target steering angles can be changed in a pulsed manner, for example, in a sinusoidal wave, rectangular wave, triangular wave, sawtooth wave, etc.

[0033] In this way, when the target steering angles MSTR_FL, MSTR_FR are changed in a pulse-like manner and the integrated values ​​of the actual current values ​​obtained are compared, the influence of the suspension geometry can be reduced, thereby improving the accuracy of detecting whether or not there is an abnormality in the reducer 32.

[0034] Furthermore, in the vehicle's running state, the target steering angle can also be determined based on the environment around the vehicle. In cases such as when the vehicle is an autonomous vehicle, the driver may not operate the steering operation member 56. In such cases, the target steering angle is determined based on the curvature of the road on which the host vehicle is running, objects present in the vicinity, and the like.

[0035] Furthermore, the presence or absence of an abnormality in reducer 32 can also be detected by comparing the responsiveness of steering actuator 24. Deterioration of reducer 32 causes the responsiveness of reducer 32 to deteriorate, resulting in a deterioration in the responsiveness of steering actuator 24, and this fact can be used to detect the presence or absence of an abnormality. For example, the responsiveness of the steering actuator can be evaluated based on the gradient of change in the actual steering angle when the target steering angle is the same, the deviation between the actual steering angle and the target steering angle, etc.

[0036] Furthermore, in the above embodiment, the abnormality detection device is applied to a steering system, but it can also be applied to a vehicle height adjustment system, an active suspension system, etc., provided in a vehicle.

[0037] For example, in a vehicle height adjustment system, the vehicle height adjustment actuator may include a speed reducer. In such a case, when the loads applied to the left and right wheels of the vehicle height adjustment actuator are approximately the same and the target vehicle height values ​​are approximately the same, it is possible to detect whether or not there is an abnormality in at least one of the left and right speed reducers by comparing the integrated values ​​of the currents to the left and right vehicle height adjustment actuators. In addition, in an active suspension system, for example, an active stabilizer actuator may include a reducer, and in that case, the present embodiment can also be similarly applied.

[0038] As described above, in this embodiment, the abnormality detection device is made up of current sensor 86, and a portion of steering ECU 16 that stores and executes the abnormality detection program. Also, of the abnormality detection device, current sensor 86 and the like make up a current value detection portion, and a control target value determination portion is made up of a portion of steering ECU 16 that stores and executes S3 of the abnormality detection program represented by the flowchart in Fig. 6.

[0039] Furthermore, the present invention can be embodied in various forms with various modifications and improvements made based on the knowledge of those skilled in the art. [Explanation of symbols]

[0040] 12: Wheel steering device 16: Steering ECU 24: Steering actuator 30: Steering motor 32: Reducer 41: Flexible external gear 42: Rigid internal gear 58: Operation angle sensor 70: Motor ECU 72: CAN 76: Display 84: Steering angle sensor 86: Current sensor Patentable invention

[0041] (1) An abnormality detection device for detecting the presence or absence of an abnormality in at least one of a plurality of electric actuators each equipped with a reduction gear, An abnormality detection device that detects the presence or absence of an abnormality in the reducer included in at least one of a plurality of electric actuators, based on a control target value determined for each of the plurality of electric actuators and an actual current value, which is the current value actually supplied to each of the plurality of electric actuators.

[0042] (2) The abnormality detection device according to paragraph (1) detects the presence or absence of an abnormality in the reducer included in at least one of the plurality of electric actuators based on an actual current value, which is the current value actually supplied to each of the plurality of electric actuators, when the absolute value of the control target value determined for each of the plurality of electric actuators is greater than a set value and the control target values ​​determined for each of the plurality of electric actuators are approximately the same.

[0043] (3) The abnormality detection device according to paragraph (1) or (2) includes an actual current value detection unit that detects the actual current value actually supplied to each of the plurality of electric actuators, and when the control target values ​​determined for each of the plurality of electric actuators are approximately the same, detects the presence or absence of an abnormality in the reducer of at least one of the plurality of electric actuators by comparing the integrated values ​​of the actual current values ​​for each of the plurality of electric actuators detected by each of the actual current value detection units over a predetermined set time.

[0044] For example, if the ratio of the integrated current value for one of multiple electric actuators to the integrated current value for the other electric actuators is greater than a set ratio, it can be detected that the reducer of one electric actuator is abnormal.

[0045] (4) The abnormality detection device according to any one of (1) to (3), further comprising an actual current value detection unit that detects the actual current value actually supplied to each of the plurality of electric actuators, and when the control target value for each of the plurality of electric actuators is changed in a pulsed manner, detects the presence or absence of an abnormality in the reducer of at least one of the plurality of electric actuators by comparing the integrated values ​​of the actual current values ​​for each of the plurality of electric actuators detected by each of the actual current value detection units over a predetermined set time.

[0046] (5) An abnormality detection device according to any one of (1) to (4), including a stop control target value determination unit that changes the control target value in a pulsed manner when the vehicle is stopped.

[0047] When the vehicle is in a stopped state, there is no problem in terms of safety even if the control target value is changed in a pulsed manner for the purpose of detecting an abnormality.

[0048] (6) The abnormality detection device according to any one of (1) to (5), further comprising a driving control target value determination unit that determines the control target value based on at least one of the state of the vehicle and the state of the surroundings of the vehicle when the vehicle is in a driving state.

[0049] When the vehicle is in a traveling state, it is desirable to determine the control target value based on the state of the vehicle (the traveling speed of the vehicle, the state of operation of the operating members by the driver, etc.) and the state around the vehicle (the state of the road on which the vehicle is traveling, the relative positional relationship with objects around the vehicle, etc.).

[0050] (7) The reducers each include a wave gear device including a wave generator, a flexible external gear, and a rigid internal gear, the flexible external gear is rotatable integrally with the output shaft of the electric actuator and includes a plurality of external teeth formed on an outer circumferential surface thereof, the rigid internal gear is fixed to the main body of the reducer, is formed on an inner peripheral surface, and includes a plurality of internal teeth that are capable of fitting with some of the external teeth of the flexible external gear, The abnormality detection device according to any one of items (1) to (6) detects whether or not there is an abnormality in the reducer due to tooth skipping between the external teeth of the flexible external gear and the internal teeth of the rigid internal gear.

[0051] (8) The plurality of electric actuators are two electric actuators located on the left and right sides of the vehicle, The abnormality detection device according to any one of items (1) to (7), wherein the abnormality detection device detects that the reducer included in one of the two electric actuators is abnormal when the ratio of the integrated value of the actual current value over a predetermined set time when the control target value for each of the two electric actuators is approximately the same is greater than a set ratio greater than 1.

[0052] For example, the following formula (2) is a modification of formula (1) used in the examples. In formula (2), the value {(2+γ) / (2-γ)} corresponds to the aforementioned γx, the set ratio described in section (8). |SI_FL-SI_FR| / {(SI_FL+SI_FR) / 2}>γ···(1) SI_Fi / SI_Fj>{(2+γ) / (2-γ)} i=L,R j=R,L (2)

[0053] (9) An abnormality detection device for detecting the presence or absence of an abnormality in at least one of a plurality of electric actuators each equipped with a reduction gear, An abnormality detection device that detects the presence or absence of an abnormality in the reducer included in at least one of a plurality of electric actuators, based on the responsiveness of each of a plurality of electric actuators, which is determined based on a control target value determined for each of the plurality of electric actuators and an actual operating value, which is the actual operating value of each of the plurality of electric actuators.

[0054] The abnormality detection device described in this section can employ the technical features described in any one of sections (1) to (8).

Claims

1. An abnormality detection device that detects the presence or absence of an abnormality in at least one of a plurality of electric actuators each equipped with a reducer, the abnormality detection device detects the presence or absence of an abnormality in the reducer included in at least one of the plurality of electric actuators based on a control target value determined for each of the plurality of electric actuators and an actual current value which is a current value actually supplied to each of the plurality of electric actuators, An abnormality detection device that detects the presence or absence of an abnormality in the reducer included in at least one of the plurality of electric actuators based on an actual current value, which is the value of current actually supplied to each of the plurality of electric actuators, when the absolute value of the control target value determined for each of the plurality of electric actuators is greater than a set value and the control target values ​​determined for each of the plurality of electric actuators are approximately the same.

2. An abnormality detection device that detects the presence or absence of an abnormality in at least one of a plurality of electric actuators each equipped with a reducer, the abnormality detection device detects the presence or absence of an abnormality in the reducer included in at least one of the plurality of electric actuators based on a control target value determined for each of the plurality of electric actuators and an actual current value which is a current value actually supplied to each of the plurality of electric actuators, an actual current value detection unit that detects the actual current value actually supplied to each of the plurality of electric actuators, and when the control target values ​​determined for each of the plurality of electric actuators are approximately the same, detects the presence or absence of an abnormality in the reducer of at least one of the plurality of electric actuators by comparing integrated values ​​of the actual current values ​​for each of the plurality of electric actuators detected by each of the actual current value detection units over a predetermined set time.

3. An abnormality detection device that detects the presence or absence of an abnormality in at least one of a plurality of electric actuators each equipped with a reducer, the abnormality detection device detects the presence or absence of an abnormality in the reducer included in at least one of the plurality of electric actuators based on a control target value determined for each of the plurality of electric actuators and an actual current value which is a current value actually supplied to each of the plurality of electric actuators, an actual current value detection unit that detects the actual current value actually supplied to each of the plurality of electric actuators, and when the control target value for each of the plurality of electric actuators is changed in a pulsed manner, detects the presence or absence of an abnormality in the reducer of at least one of the plurality of electric actuators by comparing integrated values ​​of the actual current values ​​for each of the plurality of electric actuators detected by each of the actual current value detection units over a predetermined set time.

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