OPENING/CLOSING CONTROL DEVICE

Abstract

An opening/closing body control device is provided that can quickly detect pinching even when the opening/closing body is bent due to the pinching.

An opening/closing body control device includes a motor drive unit that drives a motor for opening and closing the opening/closing body, and a control unit that controls an operation of the motor drive unit. The opening/closing control device includes a difference value calculator that calculates a current difference value that is a difference between a present value and a past value of a motor current, a differential value calculator that calculates a differential value of the current difference value, an adder that adds the current difference value and the differential value, and a pinching detection unit that judges whether or not pinching occurs at the opening/closing body based on a comparison result between the added value and a threshold.

Claims

1. An opening/closing control device comprising: a motor drive unit that drives a motor to open and close an opening/closing body, a control unit controls an operation of the motor drive unit, the control unit includes: a difference value calculation unit calculates a current difference value, which is a difference between a present value and a past value of a motor current flowing in the motor, a differential value calculation unit calculates a differential value of the current difference value calculated by the difference value calculation unit, an adding unit adds the current difference value and the differential value, a pinching detection unit that judges whether or not there is a pinching at the opening/closing body based on the result of a comparison between an added value calculated by the adding unit and a predetermined threshold value.

2. An opening/closing control device comprising: a motor drive unit that drives a motor to open and close an opening/closing body, a control unit controls an operation of the motor drive unit, the control unit includes: a difference value calculation unit calculates a speed difference value, which is the difference between a present value and a past value of a motor speed, a differential value calculation unit calculates a differential value of the speed difference value calculated by the difference value calculation unit, an adding unit that adds the speed difference value and the differential value, a pinching detection unit that judges whether or not there is a pinching at the opening/closing body based on the result of a comparison between an added value calculated by the adding unit and a predetermined threshold value.

3. The opening/closing control device according to claim 1, wherein the adding unit adds the current difference value and the differential value multiplied by a predetermined coefficient.

4. The opening/closing control device according to claim 1, wherein the differential value is a differential value obtained by differentiating the current difference value by time, or a differential value obtained by differentiating the current difference value by a position of the opening/closing body.

5. The opening/closing control device according to claim 1, wherein instead of the motor current, a motor torque, which is proportional to the motor current, is used, the pinching detection unit judges the presence or absence of pinching by comparing a difference value of the motor torque and its differential value, which are added, with a threshold value.

6. The opening/closing control device according to claim 2, wherein the adding unit adds the speed difference value and the differential value multiplied by a predetermined coefficient.

7. The opening/closing control device according to claim 2, wherein the differential value is the differential value obtained by differentiating the speed difference value by time, or the differential value obtained by differentiating the speed difference value by a position of the opening/closing body.

8. The opening/closing control device according to claim 1, wherein the opening/closing body is a rotary opening/closing body that is supported at one end on a rotary shaft and rotated around the shaft by the motor.

9. The opening/closing control device according to claim 8, wherein the opening/closing body is a back door provided at the rear of a vehicle, the motor rotates the back door via an opening/closing mechanism connected to the back door.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a system diagram for controlling an opening and closing of a back door.

[0022] FIG. 2 is a diagram showing a first embodiment of a specific configuration of a control unit.

[0023] FIG. 3A is a diagram showing a difference value calculation unit.

[0024] FIG. 3B is a graph showing changes in a motor current over time.

[0025] FIG. 4 is a graph for illustrating a pinching detection method according to an aspect of the present invention.

[0026] FIG. 5 is a diagram showing a second embodiment of a specific configuration of a control unit.

[0027] FIG. 6A is a diagram showing details of a difference value calculation unit in FIG. 5.

[0028] FIG. 6B is a graph showing changes in the motor current over a position of an opening/closing body.

[0029] FIG. 7 is a diagram showing a third embodiment of a specific configuration of the control unit.

[0030] FIG. 8A is a diagram showing details of a difference value calculation unit.

[0031] FIG. 8B is a graph showing changes in a corrected motor speed over time.

[0032] FIG. 9 is a diagram showing a fourth embodiment of a specific configuration of the control unit.

[0033] FIG. 10A is a diagram showing details of a difference value calculation unit.

[0034] FIG. 10B is a graph showing changes in the corrected motor speed over the position of the opening/closing body.

[0035] FIG. 11 is a schematic structure diagram of the back door to illustrate its operation.

[0036] FIG. 12 is a simplified diagram of the mechanism for opening and closing the back door.

[0037] FIG. 13 is a diagram showing an example of a pinching.

[0038] FIG. 14 is a diagram showing another example of a pinching.

[0039] FIG. 15 is a dynamic model diagram in the case where a pinching occurs.

[0040] FIG. 16 is a graph for explaining a conventional pinching detection.

DETAILED DESCRIPTION

[0041] Embodiments of the present invention will be described with reference to the drawings. Throughout the drawings, the same or corresponding parts are denoted by the same reference numerals. Hereinafter, a back door 51 of a vehicle illustrated in FIGS. 11 to 14 will be described as an example of an opening/closing body.

[0042] FIG. 1 is a system configuration diagram for controlling the opening and closing of the back door 51. A back door control device 100 is an example of an opening/closing unit and is equipped with a control unit 1 and a motor drive unit 2. The control unit 1 outputs control signals to control the operation of the motor drive unit 2 based on an operation unit 3 in a vehicle or an electronic key. The motor drive unit 2 outputs a drive signal to rotate or stop a motor 4 based on the control signal from the control unit 1. The motor 4 rotates forward, reverses, or stops according to the drive signal from the motor drive unit 2. Connected to the motor 4 is a door opening/closing mechanism 5 that mechanically opens and closes the back door 51 (see FIG. 12). As mentioned above, an arm 53 of the door opening/closing mechanism 5 extends or retracts in conjunction with the rotation of the motor 4 to open or close the back door 51.

[0043] A voltage detection unit 6 and a current detection unit 7 are provided on an output side of the motor drive unit 2. The voltage detection unit 6 detects a motor voltage applied to the motor 4 from the motor drive unit 2. The current detection unit 7 detects a motor current flowing in the motor 4. The motor voltage detected by the voltage detection unit 6 is input to the control unit 1. The motor current detected by the current detection unit 7 is input to the control unit 1.

[0044] The motor 4 is equipped with an angle detection unit 8. The angle detection unit 8 consists of a pulse encoder, for example, and outputs pulses synchronized with the rotation of the motor 4. A total number of the pulses represents a door angle when the back door 51 opens or closes. The door angle detected by the angle detection unit 8 is input to the control unit 1.

[0045] FIG. 2 is a diagram showing a first embodiment of a specific configuration of the control unit 1. Here, only the blocks related to pinching detection are shown (the same applies to FIGS. 5, 7, and 9 described later). The control unit 1 is equipped with a current correction unit 10, a difference value calculation unit 11, a differential value calculation unit 12, a multiplier 13, an adder 14, and a pinching detection unit 15.

[0046] The current correction unit 10 is an electric circuit that corrects a variation in the motor current caused by a variation in the motor voltage. The current correction unit 10 corrects the motor current Id detected by the current detection unit 7 in FIG. 1 according to the motor voltage Vd detected by the voltage detection unit 6. The corrected motor current Id is input to the difference value calculation unit 11.

[0047] The difference value calculation unit 11 is an electric circuit that calculates the current difference value ?Id. The current difference value ?Id is the difference between the present value of the motor current Id and the past value of the motor current Id. In detail, as shown in FIG. 3A, the difference value calculation unit 11 consists of a delay circuit 11a and a subtractor 11b. FIG. 3B shows a time change of the motor current Id. The motor current Id(t) input to the difference value calculation unit 11 is a present value(time t) shown in FIG. 3B. On the other hand, the delay circuit 11a holds a past current value Id(t?D) (time (t?D), which is shown in FIG. 3B, going back by a predetermined period D from the time t. The subtractor 11b calculates the current difference value ?Id(t) by subtracting the past current value Id(t?D) from the present current value Id(t) of the motor current Id. The calculation is shown in the following equation.

[00001]$?\mathrm{Id}\left(t\right)=\mathrm{Id}\left(t\right)-\mathrm{Id}\left(t-D\right)$

[0048] In FIG. 2, the current difference value ?Id calculated by the difference value calculation unit 11 is input to the adder 14 and also to the differential value calculation unit 12. The differential value calculation unit 12 differentiates the current difference value ?Id by time and calculates a differential value d(?Id)/dt of the current difference value. The calculated differential value d(?Id)/dt is input to the multiplier 13. The multiplier 13 multiplies the differential value d(?Id)/dt by a predetermined coefficient a to calculate a?d(?Id)/dt. In principle, the value of the coefficient a should be a=1, but in practice, an appropriate value may be selected by trial and error in an experimental process of the pinching detection. The differential value in the present invention includes the differential value multiplied by such a coefficient a.

[0049] The multiplication result of the multiplier 13 is input to the adder 14. The adder 14 adds the current difference value ?Id calculated by the difference value calculation unit 11 and a?d(?Id)/dt calculated by the multiplier 13 to calculate ?Id+[a?d(?Id)/dt]. The calculated value is input to the pinching detection unit 15 and serves as the basis for judging whether or not a pinching has occurred. In the following, a=1 for simplicity, and the pinching detection unit 15 detects the pinching based on ?Id+d(?Id)/dt.

[0050] In detail, the pinching detection unit 15 compares ?Id+d(?Id)/dt (i.e., the sum of the current difference value and the differential of the current difference value) with a predetermined threshold value Th. If ?Id+d(?Id)/dt>Th, then it judges that a pinching has occurred. If ?Id+d(?Id)/dt?Th, then it judges that a pinching has not occurred. Alternatively, if ?Id+d(?Id)/dt?Th, then it judges that a pinching has occurred, and if ?Id+d(?Id)/dt<Th, then it judges that a pinching has not occurred.

[0051] FIG. 4 is a diagram for explaining a pinching detection method according to an aspect of the invention. FIG. 4 illustrates changes in various calculated values when a pinching occurs at the back door 51. A change in the difference value of the motor current, ?Id, calculated by the difference value calculation unit 11 is represented by a curve G1. A change in the differential value d(?Id)/dt of the differential value calculated by the differential value calculation unit 12 is represented by a curve G2. A sum of the curve G1 and the curve G2, i.e., the addition of the difference value and the differential value ?Id+d(?Id)/dt, is represented by a curve G3. A difference value of the motor current when there is no bend in the back door 51 is represented by a curve G4. The curve G4 is the same as the dashed line in FIG. 16.

[0052] As can be seen from FIG. 4, in a conventional method of comparing the difference value ?Id of the motor current in the curve G1 with the threshold value Th, the change in the difference value ?Id is gradual, which delays a detection timing tb of the pinching, as also explained in FIG. 16. In contrast, in the present invention, by adding the differential value d(?Id)/dt of the curve G2 to the difference value ?Id of the curve G1, the degree of the change of the added value, ?Id+d(?Id)/dt of the curve G3, is greater than that of the difference value ?Id of the curve G1, and a rise is more steep. Therefore, by comparing the curve G3 with the threshold value Th, a timing until the curve G3 reaches the threshold value Th is shortened, and as a result, the pinching can be detected at an earlier timing tc than the conventional pinching detection timing tb.

[0053] The pinching detection unit 15 outputs a detection result according to whether or not there is pinching. If the detection result is pinched, the control unit 1 outputs a control signal to the motor drive unit 2 to stop or reverse the motor 4. The motor drive unit 2 receives the control signal and stops or reverses motor 4. This stops the back door 51. As a result, the back door 51 reversing in the reverse direction, the state of being pinched by the obstacle is eliminated.

[0054] As shown in FIG. 2, the door angle of the back door 51 detected by the angle detection unit 8 is input to the pinching detection unit 15. This is the same condition as when a pinching occurs, because when the back door 51 reaches the fully-closed position 51a in FIG. 11, the motor current increases rapidly along with the torque of the motor 4. This is to prevent misjudgment of pinching at this time. In other words, the pinching detection unit 15 does not judge that a pinching has occurred if the back door 51 is in the fully-closed position 51a even if the added value of the difference value of the motor current and its differential value reaches the threshold value Th.

[0055] FIG. 5 shows a second embodiment of a specific configuration of control unit 1. As in FIG. 2 (the first embodiment), control unit 1 is equipped with the current correction unit 10, the difference value calculation unit 11, the differential value calculation unit 12, the multiplier 13, the adder 14, and the pinching detection unit 15, but a calculations of the current difference value and the differential value of the difference value differ from those in FIG. 2. The following is a specific explanation.

[0056] In FIG. 2, as explained in FIG. 3, the difference value calculation unit 11 calculated the current difference value ?Id(t) by subtracting the past value Id(t?D) at the time t?D from the present value Id(t) at the time t of the motor current Id. In contrast, in FIG. 5, as shown in FIG. 6, the difference value calculation unit 11 used a position of the back door 51 instead of time, and subtracted the past value Id(n?D) at a position n?D from the present value Id(n) of the motor current Id at the position n, A current difference value ?Id (n) is calculated. The position here is the value corresponding to the door angle of the back door 51 (the total number of pulses mentioned above) detected by the angle detection unit 8 in FIG. 1.

[0057] In FIG. 2, the differential value calculation unit 12 differentiated the current difference value ?Id by the time to calculate the differential value d(?Id)/dt. In FIG. 5, the differential value calculation unit 12 calculates the differential value d(?Id)/dn by differentiating the current difference value ?Id by the position. Therefore, the multiplier 13 performs an operation to multiply the differential value d(?Id)/dn by a coefficient a. The adder 14 performs an operation to add the current difference value ?Id calculated by the difference value calculation unit 11 and a?d(?Id)/dn calculated by the multiplier 13. Therefore, assuming a=1, the pinching detection unit 15 compares ?Id+d(?Id)/dn with the threshold value Th to judge whether or not a pinching has occurred.

[0058] In the second embodiment, as in the first embodiment, the difference value ?Id of the motor current is added to the differential value d(?Id)/dn, so that the added value ?Id+d(?Id)/dn has a greater degree of change than the difference value ?Id. Therefore, by comparing the added value with the threshold value Th, it is possible to detect a pinching at an earlier timing than the conventional pinching detection timing, thereby reducing the time to detect the pinching.

[0059] FIG. 7 shows a third embodiment of the specific configuration of control unit 1. As in FIG. 2 (the first embodiment), the control unit 1 is equipped with the difference value calculation unit 11, the differential value calculation unit 12, the multiplier 13, the adder 14, and the pinching detection unit 15. Instead of the current correction unit 10 in FIG. 2, a speed correction unit 16 is provided. In addition, calculations of the difference value and the differential of the difference value are different from those in FIG. 2. In FIG. 2, the difference value of current and the differential value of the difference value were calculated based on the motor current I. In FIG. 7, the difference value and the difference value of the differential value are calculated based on a motor speed R (a rotation speed of the motor 4). The following is a specific explanation.

[0060] The speed correction unit 16 is an electric circuit that corrects for variations in the motor speed caused by variations in the motor voltage. The speed correction unit 16 corrects the motor speed Rd detected by the speed detection unit, not illustrated in the FIG. 7, according to the motor voltage Vd detected by the voltage detection unit 6 in FIG. 1. The corrected motor speed Rd is input to the difference value calculation unit 11.

[0061] The difference value calculation unit 11 is an electric circuit that calculates a speed difference value ?Rd, which is a difference between the present value and the past value of the corrected motor speed Rd. In detail, as shown in FIG. 8A, the difference value calculation unit 11 consists of a delay circuit 11a and a subtractor 11b. FIG. 8B shows the time change of the corrected motor speed Rd. As is clear from comparison with FIG. 3B, the corrected motor speed Rd changes inversely to the motor current Id.

[0062] A corrected motor speed Rd(t) input to the difference value calculation unit 11 is the present (time t) speed value shown in FIG. 8B. On the other hand, the delay circuit 11a holds a corrected motor speed Rd (t?D) in the past (time (t?D), which is the time (t?D) backward by a predetermined period D from the time t) shown in FIG. 8B. The subtractor 11b calculates a speed difference value ?Rd(t) by subtracting the present value Rd(t) from the past value Rd(t?D) of the corrected motor speed Rd. The calculation is shown by the following equation.

[00002]$?\mathrm{Rd}\left(t\right)=\mathrm{Rd}\left(t-D\right)-\mathrm{Rd}\left(t\right)$

[0063] Returning to FIG. 7, the speed difference value ?Rd calculated by the difference value calculation unit 11 is input to the adder 14 and also to the differential value calculation unit 12. The differential value calculation unit 12 differentiates the speed difference value ?Rd by the time and calculates a differential value d(?Rd)/dt of the speed difference value. The calculated differential value d(?Rd)/dt is input to the multiplier 13 and multiplied by a coefficient a (here a=1). The adder 14 calculates ?Rd+d(?Rd)/dt by adding the speed differential value ?Rd calculated by the differential value calculation unit 11 and d(?Rd)/dt calculated by the multiplier 13. The calculated value is input to the pinching detection unit 15.

[0064] The pinching detection unit 15 compares ?Rd+d(?Rd)/dt (i.e., a sum of the speed difference value and the differential of the speed difference value) with the predetermined threshold value Th. If ?Rd+d(?Rd)/dt>Th, it judges that a pinch has occurred. If ?Rd+d(?Rd)/dt?Th, it judges that no pinch has occurred. Alternatively, if ?Rd+d(?Rd)/dt?Th, it judges that a pinching has occurred, and if ?Rd+d(?Rd)/dt<Th, it judges that no pinching has occurred.

[0065] In the third embodiment as described above, by adding the differential value d(?Rd)/dt of the differential value to the difference value ?Rd of the motor speed, this added value ?Rd+d(?Rd)/dt has a greater degree of change than the difference value ?Rd. Therefore, by comparing the added value with the threshold value Th, it is possible to detect the pinching at an earlier timing than the conventional pinching detection timing. Thereby, the time required to detect the pinching can be shortened.

[0066] FIG. 9 shows a fourth embodiment of the specific configuration of control unit 1. As in FIG. 7 (the third embodiment), control unit 1 is equipped with the speed correction unit 16, the difference value calculation unit 11, the differential value calculation unit 12, the multiplier 13, the adder 14, and the pinching detection unit 15. A calculation of a speed difference value and a differential of the difference value differs from that in FIG. 7. The following is a specific explanation.

[0067] In FIG. 7, as explained in FIG. 8, the difference value calculation unit 11 calculated the speed difference value ?Rd(t) by subtracting the present value Rd(t) at time t from the past value Rd(t?D) at time t?D of the corrected motor speed Rd. In contrast, in FIG. 9, as shown in FIG. 10, the difference value calculation unit 11 uses the position of the back door 51 instead of time, and subtracts the present value Rd(n) at the position n from the past value Rd(n?D) of the corrected motor speed Rd at the position n?D to obtain and calculating the difference speed value ?Rd(n). The position corresponds to a door angle of the back door 51 (a pulse counted value of the angle detection unit 8), as in the second embodiment.

[0068] In FIG. 7, the differential value calculation unit 12 differentiated the speed difference value ?Rd by the time to calculate the differential value d(?Rd)/dt. In FIG. 9, the differential value calculation unit 12 calculates the differential value d(?Rd)/dn by differentiating the speed difference value ?Rd by the position. Therefore, the multiplier 13 performs the operation of multiplying the differential value d(?Rd)/dn by the coefficient a (here a=1). In addition, the adder 14 performs the operation of adding the speed difference value ?Rd calculated by the difference value calculation unit 11 and d(?Rd)/dn calculated by the multiplier 13. Therefore, the pinching detection unit 15 compares ?Rd+d(?Rd)/dn with the threshold value Th to judge whether or not a pinching has occurred.

[0069] In the fourth embodiment as described above, as in the third embodiment, the differential value d (?Rd)/dn of the difference value is added to the difference value ?Rd of the motor speed, whereby the added value ?Rd+d (?Rd)/dn is calculated. The added value has a larger degree of change than the difference value ?Rd. Therefore, by comparing the added value with the threshold value Th, it is possible to detect the pinching earlier than the conventional pinching detection timing. This enables shortening of the time to detect the pinching.

[0070] As described above, the exemplary embodiment of the present invention has a difference value calculation unit 11 that calculates the difference between the present value and the past value of the current of the motor 4 or the speed of the motor 4, a differential value calculation unit 12 that calculates the differential value of the difference value calculated by the difference value calculation unit 11, and an adder 14 that adds these difference value and differential value. Then, by comparing the added value of the difference value and differential value with the threshold value Th, the presence or absence of the pinching at the back door 51 is judged. Thus, even if the back door 51 is bent due to the pinching, the presence or absence of pinching can be detected more quickly than with the conventional method of detecting the presence or absence of pinching using only the difference value.

[0071] In addition to the embodiments described above, various other embodiments can be employed in the present invention. For example, in FIG. 2 and FIG. 5, the difference value of the motor current and the differential value were added, and the added value was compared with a threshold value to judge whether or not a pinching has occurred. In contrast, a motor torque can be used instead of the motor current. In other words, when the motor torque=the motor current?a torque constant is established, the motor torque is proportional to the motor current. Therefore, instead of the difference value of the motor current, the difference value of the motor torque can be calculated, and the value obtained by adding the difference value and the differential value can be compared with the threshold value to judge whether or not pinching occurs.

[0072] In the above mentioned example, a motor 4 is provided for the back door 51. The motors may be provided for both a left side and a right side of the back door 51. In this case, the back door control device 100 is provided for each motor. If both the right side and the left side of the back door 51 are driven by each motor, the amount of the bend of the back door 51 when pinching occurs will be reduced compared to when only one side is driven by a motor, but the bend will still occur.

[0073] Furthermore, in the embodiments described above, the back door of a vehicle was used as an example of an opening/closing body. The present invention can be applied to a rotary type open/close body other than back doors, as long as one end is supported by a rotating shaft and rotated around the shaft by a motor. For example, the invention can be applied to the control of a rotary gate installed in a garage.

[0074] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.