JP2008148412A - Motor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely detect an angle of a wiper arm, and to correct the angle of the wiper arm. <P>SOLUTION: The angle at the operation of the wiper arm 14 can be precisely detected from a relative angle (θ1) detected by a high-precision relative angle sensor 30 for detecting a rotational angle of an input shaft 22 of a reduction gear 20 to which the wiper arm 14 is attached, and an absolute angle (θ2) which is detected by an absolute angle sensor 32 for detecting a rotational angle of an output shaft 28 of the reduction gear 20. Furthermore, the angle of the wiper arm 14 can be corrected by detecting the relative angle (θ1) and the absolute angle (θ2) in non-loading states in advance, and by creating a correction value or a correction operation formula on the basis of the detection result in advance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor control device including a reduction gear that receives a rotational driving force of a motor and decelerates a rotation speed at a predetermined reduction ratio.

  2. Description of the Related Art Conventionally, for example, a pair of wiper arms to which wiper blades are attached in order to wipe a vehicle window has a structure that is driven independently of each other (vehicle facing wiper system).

  Generally, in a vehicular facing wiper system, a wiper arm wipes a wiping range while reciprocating from a lower inversion position to an upper inversion position in the same direction and in the same cycle. At this time, the wiper arms are operated by changing the speed of the wiper arms according to the position of the wiper arms so that the wiper arms do not contact each other and do not disturb the field of view. For this reason, it is necessary to detect the angle of the wiper arm.

  In order to detect the angle of the wiper arm, there is known one in which a two-pole magnet is attached to the output shaft of a speed reducer for driving the wiper arm, and the direction of the magnetic field is detected by a magnetic sensor (such as a hall sensor). In this case, an error may occur between the actual angle of the wiper arm and the detected angle depending on the positional relationship between the magnet and the magnetic sensor and the magnetized state of the magnet. In other words, accuracy is not very good.

In order to eliminate this inaccuracy, the wiping area is divided into several (for example, four) zones, and the output of the speed reducer for driving the wiper arms to detect in which zone each wiper arm is located. It has been proposed to attach a sensor to the shaft (see Patent Document 1). In Patent Document 1, in order to detect where each wiper arm is located in the range detected by the sensor (absolute angle sensor), a relative angle sensor is attached to the motor shaft of the motor for driving the speed reducer. The position of the wiper arm is detected.
Special table 2005-535512 gazette

  However, in the conventional motor control device, if the wiping area changes depending on the type of vehicle, etc., it is necessary to change the plate used to detect the range in which the wiper arm is located, and the detection accuracy of the sensor for detection Therefore, the angle of the wiper arm cannot be detected with high accuracy.

  Further, when either the relative angle sensor or the absolute angle sensor fails, the wiper arm cannot be operated.

  In consideration of the above facts, the present invention has an object to provide a motor control device that can accurately detect the angle of the wiper arm and correct the angle of the wiper arm.

  According to a first aspect of the present invention, there is provided an absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives rotational driving of a motor and decelerates a rotational speed at a predetermined reduction ratio. A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to an input shaft of the speed reducer connected to a rotation shaft of the motor, and an absolute angle of the absolute angle sensor. Correction means for correcting using the relative angle of the relative angle sensor.

  According to the first aspect of the invention, by correcting the detection value of the absolute angle sensor using the relative angle sensor, it is possible to recognize the angle with high accuracy even if the absolute angle sensor has relatively low accuracy. Become.

  According to a second aspect of the present invention, in the first aspect of the present invention, the correction unit is configured to determine the absolute angle based on a correlation between detection values of the absolute angle sensor and the relative angle sensor. It is characterized by generating correction data of a detection value by a sensor.

  According to the second aspect of the present invention, the correction means generates correction data based on the correlation between the detected values of the absolute angle sensor and the relative angle sensor. Thereby, the angle detection of the relative angle sensor with high accuracy can be reflected in the detection value of the absolute angle sensor.

  The invention described in claim 3 is the invention described in claim 2, further comprising storage means for storing the correction data in advance.

  According to the third aspect of the present invention, the correction data is stored in advance as an embodiment of the correction of the absolute angle sensor, so that the calculation process is not delayed and the highly accurate angle can always be recognized. .

  According to a fourth aspect of the present invention, there is provided an absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives rotational driving of a motor and decelerates a rotational speed at a predetermined reduction ratio. A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to the input shaft of the speed reducer connected to the rotation shaft of the motor, A failure of the absolute angle sensor or the relative angle sensor is determined based on energization information and the absolute angle detected by the absolute angle sensor or the relative angle detected by the relative angle sensor.

  According to the fourth aspect of the present invention, it is possible to know a problem of either the absolute angle sensor or the relative angle sensor.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, if any of the absolute angle sensor or the relative angle sensor has a problem, a problem has occurred. The absolute angle of the output shaft is obtained by using the one that is not present.

  According to the fifth aspect of the present invention, if any sensor fails, it is not disabled immediately and can be used continuously by substituting a sensor that is not malfunctioning. .

  According to a sixth aspect of the present invention, there is provided an absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives a rotational drive of a motor and decelerates a rotational speed at a predetermined reduction ratio. A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to the input shaft of the speed reducer connected to the rotation shaft of the motor, An abnormality of the speed reducer is detected based on energization information and an absolute angle detected by the absolute angle sensor or a relative angle detected by the relative angle sensor.

  According to the sixth aspect of the invention, since there is a relative angle sensor on the input shaft and an absolute angle sensor on the output shaft, it is possible to determine the abnormality of the speed reducer.

  According to a seventh aspect of the present invention, there is provided an absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives a rotational drive of a motor and decelerates a rotational speed at a predetermined reduction ratio. A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to an input shaft of the speed reducer connected to a rotation shaft of the motor, and The output shaft load torque allowing the elastic deformation of the speed reducer based on the difference between the coefficient and the absolute angle of the absolute angle sensor and the relative angle of the relative angle sensor. It is characterized by calculating.

  According to the seventh aspect of the present invention, the difference between the detected value of the relative angle sensor of the input shaft and the detected value of the absolute angle sensor of the output shaft correlates with the load torque. On the other hand, since the reduction gear is elastically deformed due to, for example, a gear meshing tolerance, a coefficient of this elastic deformation is obtained. As a result, the load torque of the output shaft that allows the elastic deformation of the speed reducer can be calculated.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein a wiper arm for wiping a vehicle window glass as a driving load of the output shaft is attached to the output shaft, The wiper arm reciprocates in the vehicle window by forward and reverse rotation of the motor.

  According to the eighth aspect of the present invention, the load of the wiper arm greatly changes depending on the running state of the vehicle and the environmental change. Obtaining a highly accurate angle with respect to this change can avoid, for example, mutual interference when simultaneously operating two unit wiper arms provided side by side, and ensure a wide wiping area.

  The invention according to claim 9 is the invention according to claim 7, wherein a wiper arm for wiping a vehicle window glass as a drive load of the output shaft is attached to the output shaft, and the forward rotation and reverse rotation of the motor The wiper arm reciprocates on the vehicle window glass, and the friction state applied to the wiper arm is determined from the calculated load torque.

  According to the ninth aspect of the present invention, the friction state can be determined using the load torque calculated from the difference between the detected value of the relative angle sensor of the input shaft and the detected value of the absolute angle sensor of the output shaft. it can.

  A tenth aspect of the invention further includes a relative angle correction unit that corrects the relative angle detected by the relative angle sensor in accordance with the friction state in the invention of the ninth aspect.

  According to the invention described in claim 10, the wiper arm can accurately reciprocate in the wiping range by correcting the relative angle according to the friction state.

  The invention described in claim 11 is characterized in that, in the invention described in claim 10, the electric power supplied to the motor is changed in accordance with the position of the wiper arm in accordance with the friction state.

  According to the eleventh aspect of the invention, when the friction is large, the wiper arm can be operated similarly to the case where the friction is small by increasing the electric power supplied to the motor.

  According to a twelfth aspect of the present invention, in the invention of the tenth aspect, when the friction coefficient is high from the friction state, the forward rotation and reverse rotation positions of the motor indicate that the wiper arm reciprocates the vehicle window. Control is performed in a direction that is wider than a predetermined range of movement.

  According to the twelfth aspect of the present invention, when the friction coefficient is high, the wiping angle is narrowed. Therefore, the wiper arm accurately reciprocates in the wiping range by controlling in a direction wider than the predetermined inversion position. Can do.

  According to a thirteenth aspect of the invention, in the invention of the twelfth aspect, the torque is calculated in the vicinity of the forward rotation position and the reverse rotation position of the motor.

  According to the thirteenth aspect of the invention, when the wiper arm wipes, the frictional state changes near the center of the wiping angle and near the reversing position. Therefore, the wiping angle is widened by calculating the torque near the reversing position. By controlling the direction, the wiper arm can reciprocate accurately in the wiping range.

  According to a fourteenth aspect of the present invention, in the invention according to any one of the ninth to thirteenth aspects, the friction state includes an inertia torque and a friction required for the wiper arm to wipe the vehicle window glass. It is characterized by the total torque.

  According to the fourteenth aspect of the present invention, the friction state can be determined by calculating the sum of the inertia torque and the friction torque.

(First embodiment)
FIG. 1 is a schematic explanatory diagram illustrating a control flow of the wiper system according to the present embodiment.

  As shown in FIG. 1, the wiper switch 10 is connected to the controller 12. The wiper switch 10 sends operation signals such as the operation and operation speed of the wiper arm 14 to the controller 12.

  The controller 12 includes a memory 16. The controller 12 is connected to a motor 18 that is a drive source of the wiper arm 14. The controller 12 drives and controls the motor 18 based on the operation signal from the wiper switch 10 to operate the wiper arm 14.

  The memory 16 stores correction information of the operating state of the wiper arm 14, that is, the rotation angle (absolute angle (θ2) shown in FIG. 4) from a predetermined reference position (for example, the lower reverse position). The correction information will be described later.

  The rotation shaft of the motor 18 is connected to the speed reducer 20. The speed reducer 20 includes an input shaft 22 that is coaxially coupled (may be common) to the rotation shaft of the motor 18, a worm gear 24 attached to the input shaft 22, and a worm wheel 26 that meshes with the worm gear 24. It is equipped with. An output shaft 28 is attached to the center of the worm wheel 26. The motor 18 rotates the input shaft 22 based on the electric power supplied from the controller 12, decelerates the rotational speed via the worm gear 24 and the worm wheel 26 that operate in conjunction with the input shaft 22, and outputs to the output shaft 28. Actuate the attached wiper arm 14.

  In the speed reducer 20, the output shaft 28 can be rotated forward / reversely within a range of 360 degrees with a predetermined reduction ratio, but the rotation angle range is determined according to the wiping range in which the wiper arm 14 wipes the vehicle window. In other words, if all 360-degree positions are recognized, all wiping ranges can be handled.

  Here, the input shaft 22 is provided with a relative angle sensor 30, and the output shaft 28 is provided with an absolute angle sensor 32. The relative angle sensor 30 and the absolute angle sensor 32 are each connected to the controller 12 and send the respective detected values to the controller 12.

  The relative angle sensor 30 is composed of a motor pulse encoder, detects the rotation state of the input shaft 22 (relative angle (θ1) shown in FIG. 4), and sends the detection result to the controller 12.

  The absolute angle sensor 32 includes an output shaft pulse encoder that may cause an error depending on the positional relationship between the magnet and the magnetic sensor or the magnetized state of the magnet. Specifically, the absolute angle sensor 32 is configured by a Hall IC or the like that outputs a pulse when the output shaft 28 rotates at a relatively rough predetermined angle, a reference position is set in advance, and the output shaft 28 from the reference position is set. The rotation angle (absolute angle (θ2) shown in FIG. 4) is detected, and the detection result is sent to the controller 12.

  The above-described correction information is stored in the memory 16 of the controller 12. This correction information is obtained in advance by calculating the absolute angle (θ2 in FIG. 4) of the output shaft 28 with respect to the change in the relative angle (θ1 in FIG. 4) of the input shaft 22 measured in the no-load state (that is, the wiper arm 14 is not attached). Is calculated on the basis of an error corresponding to one rotation (360 degrees) of the output shaft 28. The memory 16 may store a correction calculation formula for calculating correction information instead of the correction information.

(Generation basis for correction information of the absolute angle sensor 32)
As shown in FIG. 4, if the x-axis of the x-y axis is the detection angle θ1 by the relative angle sensor 30 and the y-axis is the detection angle θ2 by the absolute angle sensor 32, the drive shaft (input) of the same system is originally used. Since they are the shaft 22 and the output shaft 28), θ1 and θ2 are in a directly proportional relationship, and become a characteristic curve that rises straight to the right as shown by the solid line in FIG.

  However, the absolute angle sensor 32 that detects θ2 has an error between the actual angle of the wiper arm 14 and the detected angle depending on the positional relationship between the magnet and the magnetic sensor and the magnetized state of the magnet. There is a detection difference between the detection values of the sensor and the relative angle sensor 30, and the correlation is as shown by the chain line in FIG.

  Therefore, the error e at the required angle of the absolute angle sensor 32 is detected by trusting the detection value θ1 of the relative angle sensor 30 (e = θ1−θ2).

  If this error is stored in advance in the memory 16 of the controller 12 and the detected value θ2 detected by the absolute angle sensor 32 is corrected, an accurate wiping operation angle of the wiper arm 14 can be obtained by the relative angle sensor 30. (Θ2 ′ = θ1). In the correction, the memory 16 of the controller 12 may store a map of correction values for the detection values of the absolute angle sensor 32, or a correction calculation using the detection values of the absolute angle sensor 32 as parameters. You may memorize a formula.

  Further, since the relative angle sensor 30 and the absolute angle sensor 32 are attached to the input shaft 22 and the output shaft 28, respectively, various problems occur depending on the detection states of the relative angle sensor 30 and the absolute angle sensor 32. Can be determined. This defect determination will be described in detail in the second embodiment (see Table 1).

  In FIG. 4A, the play based on the meshing tolerance of the teeth of the worm gear 24 and the worm wheel 26 when the motor 18 is reversed is indicated by θb. When this play is recognized, the elastic deformation in the speed reducer 20 is determined, and this is stored in the memory 16 of the controller 12 as the elastic coefficient k and detected by the relative angle sensor 30 and the absolute angle sensor 32. Based on the value, it is possible to monitor the torque due to the external load during the operation of the wiper arm 14.

  The operation of the first embodiment will be described below.

  When an operation signal for operating the wiper arm 14 is sent from the wiper switch 10 to the controller 12, the controller 12 drives and controls the motor 18. The motor 18 rotates the input shaft 22 based on the electric power supplied by the controller 12. As the input shaft 22 rotates, the worm gear 24 and the worm wheel 26 rotate, whereby the wiper arm 14 attached to the output shaft 28 operates. Accordingly, the wiper arm 14 wipes the wiping area of the vehicle window from the lower inversion position to the upper inversion position. When detecting that the wiper arm 14 has rotated to the lower inversion position or the upper inversion position, the controller 12 causes the motor 18 to rotate forward and backward, and by repeating this, the wiper arm 14 reciprocates in the wiping area of the vehicle window.

  The rotation angle of the wiper arm 14 is detected from the relative angle sensor 30 and the absolute angle sensor 32, and when the angle is deviated compared to the target value, the power supplied to the motor 18 is controlled to correct the angle. .

  FIG. 2 shows a flow of creating correction information.

  As shown in FIG. 2, the rotation angle is detected by the relative angle sensor 30 and the rotation angle by the absolute angle sensor 32 in a no-load state where there is no external load torque, that is, the wiper arm 14 is not attached to the output shaft 28. Detection is performed.

  In step 100, as an initial setting of the absolute angle sensor 32, a reference position for detecting the rotation angle of the output shaft 28 of the speed reducer 20 is determined. From this reference position, a rotation angle (absolute angle (θ2) shown in FIG. 4) by which the output shaft 28 is rotated is detected. When the reference position is determined, the process proceeds to step 102.

  In step 102, as an initial setting of the relative angle sensor 30, the count value of the motor pulse encoder that detects the rotation state of the input shaft 22 (relative angle (θ1) shown in FIG. 4) is reset, that is, set to “0”. 104.

  In step 104, the rotation of the motor 18 is started, and the routine proceeds to step 106.

  In step 106, the output shaft 28 is rotated once (360 degrees) from the reference position determined in step 100, and the process proceeds to step 108.

  As shown in FIG. 3, the absolute angle sensor 32 detects a pulse at every predetermined angle at which the output shaft 28 rotates from the reference value determined in step 100. The relative angle sensor 30 detects the rotation state (relative angle (θ1) shown in FIG. 4) from the time when the count value of the motor pulse encoder is reset in step 102.

  In step 108, the rotation state of the input shaft 22 (relative angle (θ1 shown in FIG. 4) with respect to a predetermined rotation angle of the output shaft 28 (absolute angle (θ2) shown in FIG. 4) while the output shaft 28 rotates 360 degrees). )), That is, the pulse count value MC of the motor pulse encoder is read, and the routine proceeds to step 110.

  In step 110, an error (difference) of each position for 360 degrees corresponding to a predetermined angle (absolute angle (θ2) shown in FIG. 4) is calculated. The error (difference) is corrected from the angle (relative angle (θ1) shown in FIG. 4) detected corresponding to the angle of the output shaft 28 (absolute angle (θ2) shown in FIG. 4). Create By setting the correction value to θ2 ′ = θ2 + e, θ2 ′ = θ1. The error is calculated and the process proceeds to step 112.

  In step 112, a correction value that eliminates the error or a correction arithmetic expression that uses the count value of the output shaft pulse encoder as a parameter is stored in the memory 16, and this routine ends.

  FIG. 4 is a graph showing the relationship between the correction array and the correction value based on the relative angle (θ1) and the absolute angle (θ2).

  The target is to rotate the output shaft 28 (absolute angle (θ2)) in proportion to the relative angle (θ1) that the input shaft 22 rotates, but in practice, as indicated by the chain line in FIG. Rotate to. Therefore, as shown in FIG. 4B, the relative angle (θ1) with respect to the correction array e = θ1−θ2 is calculated, and the correction value (θ2 ′) is calculated as shown in FIG. it can.

  Further, as shown in FIG. 4A, when the motor 18 is rotated in the reverse direction, the difference until the relative angle (θ2) of the output shaft 28 changes with respect to the relative angle (θ1) of the input shaft 22 can be detected. Thereby, the play (θb) when the speed reducer 20 rotates in reverse can also be detected.

  In order to calculate the correction data, the output shaft 28 is rotated 360 degrees. However, in order to wipe the vehicle window with the wiper arm 14, the rotation angle of the wiper arm 14 differs depending on the mounted vehicle. Therefore, when the controller 12 detects the angle of the lower inversion position and the angle of the upper inversion position among the rotation angles (θ2) of the output shaft 28 as shown in FIG. Or control to reverse.

  Since the position of the wiper arm 14 can be detected from the absolute angle (θ2) of the output shaft 28 and can be corrected using the correction value (θ2 ′), the power supply returns from a state where the power supply was cut off during the operation of the wiper arm 14. Even in this case, the accurate angle of the wiper arm 14 can be detected, the initial value of the relative angle (θ1) of the input shaft 22 can be determined, and the motor 18 can be controlled.

  Based on the relative angle (θ1) detected from the highly accurate motor pulse encoder, correction data (θ2 ′) for the absolute angle (θ2) detected from the output shaft pulse encoder is created in advance, so that the wiper arm 14 The accuracy of angle detection can be improved.

(Second Embodiment)
The second embodiment of the present invention will be described below. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description of the configuration is omitted.

  The second embodiment is characterized in that the angle of the wiper arm 14 is accurately detected in the first embodiment, and the relative angle sensor 30 and the absolute angle sensor 32 are used in combination to correct the angle. As shown in FIG. 5, it becomes easy to specify a sensor or cause of the failure, and torque can be calculated.

  In the state where electric power is supplied to the motor 18, the relative angle (θ1) of the input shaft 22 changes, the absolute angle (θ2) of the output shaft 28 also changes, and the absolute angle (θ2) and the relative angle When the angle difference from (θ1) is small, it is determined as normal. When it is determined to be normal, the relative angle (θ1) is preferentially controlled, and a load torque described later can be detected.

  If the relative angle (θ1) of the input shaft 22 changes while power is being supplied to the motor 18, but the absolute angle (θ2) of the output shaft 28 does not change, the absolute value of the output shaft 28 It is determined that a problem has occurred in the absolute angle sensor 32 that detects the angle (θ2), and control is performed using only the relative angle (θ1) of the input shaft 22.

  Conversely, when power is being supplied to the motor 18, the absolute angle (θ2) of the output shaft 28 is changed, but the relative angle (θ1) of the input shaft 22 is not changed, the input shaft 22 is changed. It is determined that a problem has occurred in the relative angle sensor 30 that detects the error, and control is performed using only the correction value (θ2 ′).

  If it is determined that a problem has occurred in either the relative angle sensor 30 or the absolute angle sensor 32, the defect information is transmitted to a higher-level electronic control unit (ECU).

  When the supply of electric power to the motor 18 is less than a predetermined duty and the relative angle (θ1) of the input shaft 22 changes, but the absolute angle (θ2) of the output shaft 28 does not change, the output shaft 28 Since it can be determined that the load is not transmitted to the motor 18, an abnormality of the speed reducer 20 can be detected.

  When the load is applied to the output shaft 28 more than usual due to the running state of the vehicle, environmental changes, and the like, the wiper arm 14 determines the absolute angle (θ2) or the corrected angle (θ2 ′) of the output shaft 28 and the input shaft of the speed reducer 20. There is a difference between the relative angle of 22 (θ1). By obtaining the elastic deformation coefficient (k) of the speed reducer 20 in advance, the load torque (T) of the output shaft 28 is obtained by setting the elastic coefficient (k) of the speed reducer 20 to the angle difference (θ2′−θ1). The multiplication can be performed using T = k × (θ2′−θ1).

  In particular, the load torque is detected from the angle difference, and after the torque of a predetermined level or more that may cause an abnormality in the speed reducer 20 is applied, the relative angle (θ1) of the input shaft 22 of the speed reducer 20 is changed but output. If there is no change in the absolute angle (θ2) of the shaft 28, it can be determined that the speed reducer 20 has become abnormal. If there is an angle difference of one worm gear between the relative angle (θ1) and the absolute angle (θ2), it is determined that one worm gear is damaged, and the correction data (θ2 ′) is used as a reference. Control as.

  Since the load torque of the output shaft 28 can be detected, when a predetermined torque that may cause an abnormality in the speed reducer 20 is detected, the speed reducer 20 can be forcibly stopped to prevent the worm gear from being damaged. .

  Note that the relative angle sensor 30 that detects the relative angle (θ1) of the input shaft 22 of the speed reducer 20 may count a signal like a ring magnet and a Hall IC.

  The absolute angle sensor 32 that detects the absolute angle (θ2) of the output shaft 28 includes a combination of a magnet coupled to the output shaft 28 and a Hall element or a magnetoresistive element that detects the direction of the magnetic field, a resolver, It may be a binary angle absolute rotary encoder.

(Third embodiment)
The third embodiment of the present invention will be described below. In the third embodiment, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and description of the configuration is omitted.

  A feature of the third embodiment is that in the second embodiment, the load torque can be calculated by using the relative angle sensor 30 and the absolute angle sensor 32 together to correct the wiping angle of the wiper arm 14. The wiper arm 14 can be accurately controlled according to the friction state of the wiper blade from the calculated load torque.

  FIG. 5 is a schematic explanatory diagram illustrating a flow of control of the wiper system according to the third embodiment.

  The rubber wiper blade 34 is connected to the wiper arm 14. The wiper blade 34 contacts and wipes the window glass according to the operation of the wiper arm 14.

  As shown in FIG. 5, the load torque of the output shaft 28 of the speed reducer 20 and the frictional load between the window glass and the wiper blade 34 are applied to the wiper arm 14, and the wiper arm 14 is deformed.

  The friction coefficient between the window glass and the wiper blade 34 varies greatly between the wet state and the dry state of the window glass, and the force applied to the wiper arm 14 also varies with the change in the friction coefficient. When the window glass is dry, the friction coefficient is large, and if the proper wiping angle is set when it is wet, the output shaft 28 of the speed reducer 20 connecting the wiper arm 14 and the speed reducer 20 is set. Even if the wiper arm 14 is operated at the set wiping angle, the wiper arm 14 is deformed by the frictional force between the window glass and the wiper blade 34 and operates within a narrower range than the set wiping angle. Therefore, the operation state of the wiper arm 14 differs depending on whether the window glass is dry or wet.

  Therefore, the friction coefficient applied to the wiper arm 14 is estimated based on the calculated load torque (T), and the wiper arm 14 is controlled in accordance with the change in the friction state based on the friction coefficient.

  Here, the output shaft 28 generates a total torque (T1 + T2) that is a sum of the inertia torque (T1) and the friction torque (T2).

  The inertia torque (T1) is calculated by T1 = J · α [N · m] based on inertia (J), where α is the angular acceleration of the wiper arm 14 to accelerate and decelerate the wiper arm 14.

  Friction torque (T2) is expressed as follows: friction coefficient (μ) between the window glass and the wiper blade 34, the force that the wiper arm 14 holds the wiper blade 34 is F [N], and the length of the wiper arm 14 is r [m]. = Μ · F · r [N · m].

  Values other than the friction coefficient do not change greatly, but the friction coefficient (μ) is about 0.1 to 0.3 when the window glass is wet (when wet), whereas it is dry (when dry). ) Is about 1.0 to 1.3. For this reason, the friction torque (T2) of the output shaft 28 increases at the time of Dry compared to the time of Wet.

  When a load is applied to the output shaft 28, as described in the second embodiment, the absolute angle of the output shaft 28 (detection data θ2 and correction data θ2 ′ are shown in FIG. 4 but here referred to as θ2). And the relative angle of the input shaft 22 (θ1 shown in FIG. 4), and by obtaining the elastic deformation coefficient (k) in advance, the load torque (T) of the output shaft 28 is T = K × (θ2−θ1).

  FIG. 6 is a graph showing a change in the coefficient of friction when the x-y axis is the time (t) and the y-axis is the difference between the absolute angle and the relative angle (θ2−θ1).

  The output shaft 28 represented by the difference (θ2−θ1) between the absolute angle of the output shaft 28 (θ2 shown in FIG. 4) that changes with time and the relative angle (θ1 shown in FIG. 4) of the input shaft 22. From the change in the load torque (T), it can be estimated whether the friction state is a wet time indicated by a chain line or a dry time indicated by a solid line.

  The friction coefficient (μ) of the friction torque (T2) can be estimated from this friction state (in the case of Wet and in the case of Dry). The motor 18 is controlled in accordance with the friction coefficient (μ).

  FIG. 7 is a graph showing increase / decrease in power when the x-axis of the xy axis is time (t) and the y-axis is voltage (v). In addition, increase / decrease in electric power is performed by the gain (for example, duty control) of a motor drive voltage.

  When the load on the output shaft 28 increases due to friction, the number of revolutions of the motor 18 decreases, and the operation time required to wipe the window glass increases. Therefore, the friction coefficient is estimated from the friction state (see FIG. 6), the control amount is changed according to the friction coefficient, and the power supplied to the motor 16 is increased or decreased. As a result, regardless of the operating angle position of the wiper arm 14, stable operation is possible. In addition, even when the friction state changes greatly, such as from wet (chain line) to dry (solid line), the operating time of the wiper arm 14 can be stabilized and wiped off by increasing the power accordingly in accordance with the friction coefficient. it can.

  In the third embodiment, the constant wiping time is maintained by changing the power supplied to the motor 16 according to the friction state, but the absolute angle of the output shaft 28 (θ2 shown in FIG. 4). A constant wiping angle may be maintained by changing.

  FIG. 8 is a graph showing changes in the wiping angle when the x-axis of the xy axis is time (t) and the y-axis is an absolute angle (θ2).

  The reaction force of the load torque of the output shaft 28 is related to the wiper arm 14. Therefore, a larger friction is applied to the wiper arm 14 at the time of Dry than at the time of Wet. Therefore, at the time of Dry, it operates with a wiping angle narrower than the wiping angle set at the time of Wet.

  When the friction coefficient is high (solid line), the wiper arm 14 maintains a predetermined wiping angle even if the friction state changes, by setting a target wiping angle wider than when wetting (dashed line). Wiping can be performed at a stable wiping angle.

  Due to the wiping operation of the wiper arm 14, the moisture wiped by the wiper blade 34 is likely to accumulate near the lower inversion position and near the upper inversion position, and the friction coefficient of the portion may differ from other wiping ranges. Therefore, in order to wipe with a stable work time by changing the control amount, it is better to estimate the friction coefficient over almost the entire wiping angle. On the other hand, in order to change so that the wiping angle is expanded and to wipe at a stable wiping angle, it is better to estimate the friction coefficient in the vicinity of the inversion position.

It is a schematic explanatory drawing of the wiper system which concerns on 1st Embodiment. It is a flowchart which shows the flow which calculates the correction data which concern on 1st Embodiment. It is the schematic which shows the timing which detects a relative angle and an absolute angle. It is a graph which shows the relationship between a correction | amendment arrangement | sequence and a correction value from a relative angle and an absolute angle. It is an outline explanatory view of a wiper system concerning a 3rd embodiment. It is a graph showing the change of the friction coefficient which concerns on 3rd Embodiment. It is a graph showing the increase / decrease in the electric power which concerns on 3rd Embodiment. It is a graph showing the change of the wiping angle which concerns on 3rd Embodiment.

Explanation of symbols

  12 .... Controller, 14 .... Wiper arm, 18 .... Motor, 20 .... Reducer, 22 .... Input shaft, 28 ... Output shaft, 30 ... Relative angle sensor, 32 ... Absolute angle sensor

Claims (14)

An absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives rotational driving of the motor and decelerates the rotational speed at a predetermined reduction ratio;
A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to an input shaft of the speed reducer connected to a rotation shaft of the motor;
Correction means for correcting the absolute angle of the absolute angle sensor using the relative angle of the relative angle sensor;
A motor control device.   2. The correction unit generates correction data for a detection value by the absolute angle sensor based on a correlation between detection values of the absolute angle sensor and the relative angle sensor. Motor control device.   The motor control apparatus according to claim 2, further comprising a storage unit that stores the correction data in advance. An absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives rotational driving of the motor and decelerates the rotational speed at a predetermined reduction ratio;
A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to an input shaft of the speed reducer connected to a rotation shaft of the motor;
A failure of the absolute angle sensor or the relative angle sensor is determined based on energization information to the motor and an absolute angle detected by the absolute angle sensor or a relative angle detected by the relative angle sensor. Motor control device.   5. The absolute angle of the output shaft is obtained by using one of the absolute angle sensor and the relative angle sensor that does not have a failure when the failure occurs in either the absolute angle sensor or the relative angle sensor. A motor control device according to claim 1. An absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives rotational driving of the motor and decelerates the rotational speed at a predetermined reduction ratio;
A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to an input shaft of the speed reducer connected to a rotation shaft of the motor;
A motor control device that detects an abnormality of the speed reducer based on energization information to the motor and an absolute angle detected by the absolute angle sensor or a relative angle detected by the relative angle sensor. An absolute angle sensor that detects an absolute angle from a reference position with respect to an output shaft of a speed reducer that receives rotational driving of the motor and decelerates the rotational speed at a predetermined reduction ratio;
A relative angle sensor for detecting a relative angle for recognizing a rotation state without having a reference position with respect to an input shaft of the speed reducer connected to a rotation shaft of the motor;
The output of allowing the elastic deformation of the speed reducer based on the difference between the coefficient and the absolute angle of the absolute angle sensor and the relative angle of the relative angle sensor. A motor control device for calculating a load torque of a shaft.   The wiper arm for wiping the vehicle window glass as a drive load of the output shaft is attached to the output shaft, and the wiper arm reciprocates the vehicle window by forward and reverse rotation of the motor. The motor control device according to claim 7.   A wiper arm for wiping the vehicle window glass as a drive load of the output shaft is attached to the output shaft, and the load torque calculated by the wiper arm reciprocatingly moving the vehicle window glass by forward and reverse rotation of the motor. The motor control device according to claim 7, wherein a friction state applied to the wiper arm is determined from the control unit.   The motor control device according to claim 9, further comprising a relative angle correction unit that corrects the relative angle detected by the relative angle sensor according to the friction state.   The motor control device according to claim 10, wherein the electric power supplied to the motor is changed in accordance with the position of the wiper arm according to the friction state.   When the friction coefficient is high from the friction state, the forward rotation and reverse rotation positions of the motor are controlled in a direction wider than a predetermined range in which the wiper arm reciprocates the vehicle window. Item 11. The motor control device according to Item 10.   The motor control device according to claim 12, wherein the torque is calculated in the vicinity of the forward rotation position and the reverse rotation position of the motor.   The motor control according to any one of claims 9 to 13, wherein the friction state is a sum of an inertia torque and a friction torque necessary for the wiper arm to wipe the vehicle window glass. apparatus.

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