MOVING BODY CONTROL DEVICE
20220348117 · 2022-11-03
Assignee
Inventors
Cpc classification
E05F15/41
FIXED CONSTRUCTIONS
E05Y2400/44
FIXED CONSTRUCTIONS
E05F15/40
FIXED CONSTRUCTIONS
International classification
Abstract
A moving body control device controls a moving body that moves by a rotation of a motor. The moving body control device includes: a pinching detecting unit that detects pinching of an object based on a change in a physical quantity indicating a rotation state of the motor. The pinching detecting unit is configured to: determine that the pinching has occurred in a case in which a first difference of the physical quantity in a first period is equal to or greater than a first threshold value and a tendency of a change in the physical quantity in the first period is a monotonous increase or a monotonous decrease; and lower a value of the first threshold value in a case in which the tendency of the monotonous increase or the monotonous decrease of the physical quantity continues for a period longer than the first period.
Claims
1. A moving body control device that controls a moving body that moves by a rotation of a motor, the moving body control device comprising: a pinching detecting unit that detects pinching of an object due to a movement of the moving body based on a change in a physical quantity indicating a rotation state of the motor; and a control unit that controls an operation of the motor based on a detection result of the pinching detecting unit, wherein the pinching detecting unit is configured to: determine that the pinching of the object has occurred in a case in which a first difference of the physical quantity in a predetermined first period is equal to or greater than a first threshold value and a tendency of a change in the physical quantity in the first period is a monotonous increase or a monotonous decrease; and lower a value of the first threshold value in a case in which the tendency of the monotonous increase or the monotonous decrease of the physical quantity continues for a period longer than the first period.
2. The moving body control device according to claim 1, wherein the pinching detecting unit returns the first threshold value to an original value in a case in which the physical quantity does not indicate the tendency of the monotonous increase or the monotonous decrease after lowering the first threshold value.
3. The moving body control device according to claim 1, wherein the pinching detecting unit is configured to: calculate a difference between a physical quantity at a beginning of the first period and a physical quantity at an end of the first period as the first difference, calculate, for each of a plurality of second periods obtained by dividing the first period, a difference between a physical quantity at a beginning of a second period and a physical quantity at an end of the second period as each of a plurality of second differences, and determine that the tendency of the change in the physical quantity in the first period is the monotonous increase or the monotonous decrease in a case in which a ratio of the second differences equal to or greater than a second threshold value among the plurality of second differences is equal to or greater than a third threshold value.
4. The moving body control device according to claim 3, wherein where the first difference is denoted by ΔI, the second difference is denoted by ΔIs(m), the first threshold value is denoted by a, the second threshold value is denoted by β, the third threshold value is denoted by γ, and the number of ΔIs(m) that is equal to or greater than β among M ΔIs(m) in the first period is denoted by N, the pinching detecting unit is configured to: calculate a tendency score SC, which indicates the tendency of the change in the physical quantity in the first period, by
SC=N/M, and determine that the pinching of the object has occurred in a case in which ΔI≥α and SC≥γ are satisfied.
5. The moving body control device according to claim 4, wherein the pinching detecting unit determines that the pinching of the object has occurred in a case in which a relationship between M and N is M=N, and ΔI≥α and SC=1 are satisfied.
6. The moving body control device according to claim 1, wherein the physical quantity is a current flowing through the motor or a rotation speed of the motor.
7. The moving body control device according to claim 1, wherein the moving body is a seat of a vehicle or a window of the vehicle.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DETAILED DESCRIPTION
[0035] In embodiments of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention.
[0036] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same parts or corresponding parts are designated by the same reference numerals. In the following, a vehicle seat as a moving body will be taken as an example, and a case where the present invention is applied to a seat control device will be described.
[0037]
[0038] The operation unit 5 is configured of a switch for manually operating an operation of the seat 20, and the like. The motor current detecting unit 6 detects a motor current flowing through the motor 8. The motor speed detecting unit 7 detects a rotation speed of the motor 8. The motor 8 is a motor for moving the seat 20 in a direction a (front-and-rear direction). The slide mechanism 9 is coupled to the motor 8 and the seat 20, converts the rotational motion of the motor 8 into a linear motion, and moves the seat 20 in the direction a by a predetermined distance.
[0039] The seat control device 50 includes a control unit 1, a motor drive unit 2, and a threshold value storage unit 3. The control unit 1 is configured of a CPU and the like, and controls an overall operation of the seat control device 50.
[0040] The control unit 1 is provided with a pinching detecting unit 4. A function of the pinching detecting unit 4 is actually realized by software. A method of detecting the pinching will be described in detail later. The motor drive unit 2 is configured of a circuit that generates a drive signal (for example, a PWM signal) for rotating the motor 8, and the like. The threshold value storage unit 3 stores threshold values α, α′, β, and γ for the pinching detecting unit 4 to determine the presence or absence of pinching between seats. These threshold values will be described in detail later.
[0041] Next, a basic principle of the pinching detection according to one or more embodiments of the present invention will be described with reference to
[0042] In
[0043] Now, assuming that the pinching has occurred at a beginning time point n′ in the period T, the load of the motor 8 starts to increase from this time point, and the motor current also increases accordingly. Further, as a rate of an increase in the motor current increases with time, the current difference indicating the change in the motor current at regular intervals also increases. Therefore, a current difference ΔIa at an end time point n in the period T is equal to or greater than the current difference threshold value α, which is a first condition for the pinching determination. However, under this first condition alone, in a case where disturbance has occurred in the period T as illustrated in
[0044] Therefore, in one or more embodiments of the present invention, in the case of the pinching, the motor current monotonically increases in the period T as illustrated in
[0045] Therefore, in the case of the disturbance illustrated in
[0046] Next, a specific method for the pinching detection according to one or more embodiments of the present invention will be described with reference to
[0047]
[0048] The tendency difference ΔIs(m) is calculated as the difference in each motor current I at the beginning time point and the end time point of the period W for each of a plurality of periods (only one period W is illustrated in
[0049] In
ΔIs(m)=I(n−[m−1]×Z)−I(n−[m−1]×Z−W) (1)
[0050] The tendency difference ΔIs (1) is a tendency difference in the period W1, and is calculated as a difference between the motor current (current at point c) at the beginning time point (n−2Z) of the period W1 and the motor current (current at point a=I (n)) at the end time point (n) of the period W1. That is, where m=1 and W=W1 in the above equation (1), the tendency difference ΔIs(1) is expressed as the following equation.
ΔIs(1)=I(n)−I(n−W1)
[0051] The tendency difference ΔIs(2) is a tendency difference in the period W2, and is calculated as a difference between the motor current (current at point d) at the beginning time point (n−3Z) of the period W2 and the motor current (current at point b) at the end time point (n−Z) of the period W2. That is, where m=2 and W=W2 in the above equation (1), the tendency difference ΔIs(2) is expressed as the following equation.
ΔIs(2)=I(n−Z)−I(n−Z−W2)
[0052] The tendency difference ΔIs (3) is a tendency difference in the period W3, and is calculated as a difference between the motor current (current at point e) at the beginning time point (n−4Z) of the period W3 and the motor current (current at point c) at the end time point (n−2Z) of the period W3. That is, where m=3 and W=W3 in the above equation (1), the tendency difference ΔIs(3) is expressed as the following equation.
ΔIs(3)=I(n−2Z)−I(n−2Z−W3)
[0053] The tendency difference ΔIs(4) is a tendency difference in the period W4, and is calculated as a difference between the motor current (current at point f) at the beginning time point (n−5Z) of the period W4 and the motor current (current at point d) at the end time point (n−3Z) of the period W4. That is, where m=4 and W=W4 in the above equation (1), the tendency difference ΔIs(4) is expressed as the following equation.
ΔIs(4)=I(n−3Z)−I(n−3Z−W4).
[0054] The tendency difference ΔIs(5) is a tendency difference in the period W5, and is calculated as a difference between the motor current (current at point g) at the beginning time point (n−6Z) of the period W5 and the motor current (current at point e) at the end time point (n−4Z) of the period W5. That is, where m=5 and W=W5 in the above equation (1), the tendency difference ΔIs(5) is expressed as the following equation.
ΔIs(5)=(n−4Z)−I(n−4Z−W5)
[0055] The tendency difference ΔIs(6) is a tendency difference in the period W6, and is calculated as a difference between the motor current (current=I(n′) at point h) at the beginning time point (n′) of the period W6 and the motor current (current at point f) at the end time point (n−5Z) of the period W6. That is, where m=6 and W=W6 in the above equation (1), the tendency difference ΔIs(6) is expressed as the following equation.
ΔIs(6)=I(n−5Z)−I(n−5Z−W6)
[0056] As described above, when the six tendency differences ΔIs(1) to ΔIs(6) are calculated in the period T, the period T is shifted to the right direction by a predetermined amount in
[0057] By comparing each of the tendency differences ΔIs(1) to ΔIs(6) with the tendency difference threshold value β, it is possible to grasp the tendency of the change in the motor current I in the period T. For example, as illustrated in
[0058] Therefore, in one or more embodiments of the present invention, as the parameter indicating the tendency of the change in the motor current I in the period T, the tendency score SC calculated for each period T based on the tendency difference ΔIs(m) is used. Among the M tendency differences ΔIs(m) in the period T, when the number of ΔIs(m) which are equal to or greater than the threshold value β is denoted by N, the tendency score SC is calculated by the following equation.
SC=N/M (2)
[0059] The tendency score threshold value γ in
[0060] In a case where the above-described tendency differences ΔIs(1) to ΔIs(6) are all equal to or greater than the threshold value β, M=6 and N=6 in the above equation (2), so that the tendency score SC is SC=1. On the other hand, in a case where there are three tendency differences which are equal to or greater than the threshold value β, M=6 and N=3 in the above equation (2), so that the tendency score SC is SC=0.5. Further, in a case where there is no tendency difference which is equal to or greater than the threshold value β, M=6 and N=0 in the equation (2), so that the tendency score SC is SC=0.
[0061] As described above, the tendency score SC is in the range of 1≥SC≥0, and the closer the SC is to 1, the stronger the monotonous increase tendency of the motor current I is illustrated. Therefore, the tendency score SC is compared with the tendency score threshold value γ, and if SC≥γ, the motor current monotonically increases in the period T as illustrated in
[0062] In a case where the pinching is detected, the control unit 1 eliminates the pinching state by stopping or reversing the motor 8 by the motor drive unit 2.
[0063]
[0064]
[0065] As described above, in the present embodiment, in a case where the current difference ΔI is equal to or greater than the current difference threshold value α (first condition) and the tendency score SC is equal to or greater than the tendency score threshold value γ (second condition), it is determined that the pinching has occurred. The tendency score SC indicates the tendency of the change in the motor current I in the period T, and the value of the tendency score SC differs between a case where the disturbance has been applied and a case where the pinching has occurred. Therefore, in the case of the disturbance, even if the first condition is satisfied, the second condition is not satisfied, and thereby even in a case where the motor current I fluctuates greatly due to the disturbance, it is possible to avoid erroneously determining that the pinching has occurred. As a result, even if the period T for calculating the difference ΔI of the motor current I is set long in order to ensure the detection of the pinching by the flexible seat 20, the disturbance and the pinching are clearly distinguished and it is possible to suppress that the pinching is erroneously detected.
[0066] However, with only the above-described determination criteria, in a case where the “escaping operation” as illustrated in
[0067]
[0068] In the example of
[0069] Therefore, in one or more embodiments of the present invention, in a case where a state of the second condition SC≥γ, that is, the monotonous increase tendency of the motor current I continues for a period longer than the period T, the value of the current difference threshold value α used in the first condition is lowered. Therefore, it is possible to detect the pinching due to the escaping operation.
[0070] Specifically, as illustrated in
[0071] In this way, according to the present embodiment, even in a case where the occupant P performs the escaping operation in an attempt to avoid pinching, it is possible to detect the pinching by lowering the value of the current difference threshold value α. The motor current I may indicate a gradual increasing tendency not only in the escaping operation but also in a case where the seat is flexible or in a case where a soft object is pinched. Therefore, one or more embodiments of the present invention are also effective in such cases.
[0072]
[0073] In
[0074] The first motor drive unit 2a and the second motor drive unit 2b drive the first motor 8a and the second motor 8b, respectively. The first motor current detecting unit 6a and the second motor current detecting unit 6b detect motor currents flowing through the first motor 8a and the second motor 8b, respectively. The first motor speed detecting unit 7a and the second motor speed detecting unit 7b detect rotation speeds of the first motor 8a and the second motor 8b, respectively. The first pinching detecting unit 4a detects the pinching of the object in a case where the seat 20 moves in the direction a based on the current detected by the first motor current detecting unit 6a. The second pinching detecting unit 4b detects the pinching of the object in a case where the backrest 20b is tilted in the direction b based on the current detected by the second motor current detecting unit 6b.
[0075] Also in such a second embodiment, based on the same principle as in the first embodiment, the first pinching detecting unit 4a detects the pinching of the object due to the movement of the seat 20, and the second pinching detecting unit 4b detects the pinching of the object due to the tilt of the backrest 20b. Further, in a case where any of the pinching detecting units 4a and 4b detects the pinching, the first motor 8a or the second motor 8b is stopped or reversed by the motor drive units 2a and 2b, and thereby the control unit 1 eliminates the pinching state.
[0076] In the case of the second embodiment, the threshold values α, α′, β, and γ stored in the threshold value storage unit 3 may be set separately corresponding to the first pinching detecting unit 4a and the second pinching detecting unit 4b, respectively.
[0077] In one or more embodiments of the present invention, it is possible to employ various embodiments in addition to the above-described embodiments.
[0078] For example, in
[0079] Further, in the above-described embodiments, an example in which the pinching is detected based on the motor current detected by the motor current detecting units 6, 6a, and 6b is given, but the pinching may be detected based on a frequency of a ripple included in the motor current.
[0080] Further, the physical quantity for pinching detection is not limited to the current and frequency, but may be the rotation speeds of the motors detected by the motor speed detecting units 7, 7a, and 7b. In this case, when the pinching occurs, the rotation speed of the motor decreases, and the difference in rotation speed indicates the tendency of the monotonous decrease in the period T of
[0081] Further, in determining whether the current or the rotation speed is monotonically increased or monotonically decreased in the period T, other mathematical methods may be used instead of the above equations (1) and (2).
[0082] Further, in the above-described embodiments, in
[0083] Further, in
[0084] Further, in the above-described embodiments, an example in which the seat control device is equipped in the vehicle is given, but the present invention may also be applied to a power window device that opens and closes a window of the vehicle by a motor, and further, to a moving body control device used in a field other than the vehicle.
[0085] While one or more embodiments of 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. According, the scope of the invention should be limited only by the attached claims.