JP3948043B2 - Motor controller for opening / closing mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor control device for an opening / closing mechanism that detects the trapping of foreign matter by an opening / closing mechanism such as a window or sunroof of an automobile driven by a motor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a motor control device for detecting foreign object pinching by an opening / closing mechanism, for example, there is one disclosed in JP-A-6-253570. This is because the disturbance torque is estimated from the motor drive current, speed, etc. in consideration of the motor acceleration, and the chopper using the PWM pulse according to the H bridge drive device composed of four switching elements based on the estimated value. The driving current flowing through the motor is controlled by operation, the pinching force is reduced, and pinching is prevented with an inexpensive configuration.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional motor control device, for example, when used for opening and closing the power window of an automobile, a battery is used as the power source, and when the battery is replaced, the polarity is reversed and reversely connected. There arises a problem that the current to the four switching elements flows backward.
[0004]
That is, as shown in FIG. 3, when the power supply is reversely connected, the control circuit 50 for controlling the motor 1 by outputting the UP and DOWN signals for opening and closing the power window and the PWM signal for controlling the speed is provided with the backflow prevention diode 6. As a result of this, the current is not backflowed in the circuit and protected, whereas the four switching elements 3 have a problem that the current flows back in the path indicated by the arrow due to the parasitic diodes in the four switching elements 3. .
[0005]
The above problem can be solved by providing the backflow prevention diode 60 in the drive circuit through which the motor current flows as in the control circuit 50 as shown in FIG. Further, instead of providing a backflow prevention diode, a backflow prevention circuit comprising a resistor 32 and a switching element 31 can be added as shown in FIG. 5 to prevent backflow.
[0006]
However, since the current value of the motor reaches several tens of A to drive the power window of the automobile, the diode 60 in FIG. 4 or the switching element 31 in FIG. In addition, there is a problem that parts cost is high, heat generation is large, and heat dissipation measures are further required, which is not a practical method for vehicles.
[0007]
In addition, Japanese Patent Application Laid-Open No. 6-74781 discloses that pinching is prevented by differentiating the driving current of the motor to detect pinching force to a foreign object and stopping or reversing the motor by a relay. Here, in order to prevent an erroneous determination due to an inrush current generated at the start of the motor, the determination result is ignored for a certain period of time after the motor is started.
[0008]
However, in an open / close mechanism such as a power window of an automobile, the wind glass is closed while gradually adjusting the occupant to adjust the amount of wind entering the vehicle, or the open / close operation is repeated for a short time. There is a case where the position is finely adjusted, and if such a fine operation is performed within a period in which the determination time is ignored, there is a problem that the detection accuracy may be deteriorated due to foreign object pinching.
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a motor control device that can detect pinching from the start of a motor without causing a current to flow backward even when a power supply is reversely connected.
[0009]
[Means for Solving the Problems]
For this reason, the present invention drives an opening / closing mechanism that opens and closes an opening / closing object such as a window or a door, and in the motor control device of the opening / closing mechanism supplied with power from a DC power supply.
Control means for outputting a control signal to control the motor;
Relay means for connecting the DC power source to the motor and supplying power to the motor by a control signal output by the control means;
And soft-start means for gradually increasing the drive current as the differential value of the drive current to the motor during starting of the motor falls within a predetermined constant value,
A pinch detection means for detecting that a foreign object has been pinched by the opening / closing object by calculation from the time of starting the motor, using a differential value of the driving current of the motor as a parameter,
The control means performs control to reduce the driving force of the motor in the closing direction of the opening / closing object when the pinching is detected.
[0010]
It is desirable that the relay means can be connected to the motor by changing the polarity of the DC power supply by control.
Further, the pinching detection means can determine pinching of foreign matter by comparing a differential operation value of the driving current of the motor with a determination value as a determination target.
Then, it is desirable to perform reversal control on the motor once when the pinching is detected.
[0011]
[Action]
In the present invention, the control means outputs a control signal for operating the motor by operation. Since the control signal has a function of connecting the DC power source to the motor by the relaying means, the connection between the DC power source and the motor depends on the operation of the control means. As long as the control means does not operate, no current flows from the DC power source to the motor. Since the control means operates upon receiving power supply and does not operate with a power supply with reversed polarity, the drive circuit is prevented from being destroyed by the backflow of current without supplying power to the motor with the DC power supply reversed in polarity.
[0012]
When the DC power supply is connected to the motor and the motor starts, the soft start means gradually increases the drive current so that the differential value of the drive current to the motor falls within a predetermined constant value. The frictional force change when the object starts to move from the stationary state can be suppressed to a low level, and the property change of the frictional force is prevented from being erroneously detected as being caught, and the jamming detection can be started from the start. .
[0013]
The relay means is configured to connect the DC power source to the motor with the polarity changed by control, so that the motor can be rotated forward and reverse, and the opening / closing object can be opened / closed only by the control of the motor. It becomes possible.
Further, the entrapment detection means detects a driving current of the motor, so as compared with the determination value of the differential value of the drive current as a determination target determining entrapment of foreign object, a torque sensor for detecting an external force saving In addition, an effect of reducing the apparatus cost can be obtained.
When the foreign object is detected, when the reversal control is performed on the motor, the holding force can be suppressed to a low level and the foreign object can be pulled away from the apparatus.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to an example of a motor control device used for opening and closing a power window of an automobile.
FIG. 1 is a diagram illustrating the configuration of the embodiment.
The motor 1 that drives the power window 30 is connected to the positive and negative terminals of the battery via a relay 2 by a drive FET 3 and a resistor 4. The drive FET 3 can drive the motor 1 at a variable speed by a PWM signal output from the controller 5. The relay 2 is always in a state of disconnecting the motor 1 from the power source. When the UP or DOWN signal is output from the controller 5, the drive coil is activated to switch the contact to a predetermined position and connect the motor 1 to the power source. To do. As a result, the motor 1 can close and open the power window.
[0015]
The controller 5 includes a control circuit 7 that outputs UP and DOWN signals to the relay 2, a soft start circuit 8 that performs soft start when closing the power window, and a current that flows through the motor 1 by taking the voltage from the resistor 4. It comprises a current detection circuit 9 for detecting and a pinch detection circuit 11 for performing pinch detection using the detected value of the motor current. The power supply terminal is connected to the positive terminal of the battery via the diode 6 for preventing backflow, and the ground is the negative terminal of the battery. Are connected to each other and receive power supply. A power window (P / W) switch 10 is connected to the control circuit 7.
[0016]
The control circuit 7 determines the rotation direction of the motor 1 according to the operation state of the P / W switch 10 operated by the occupant, and outputs an UP or DOWN signal to the relay 2. The soft start circuit 8 is a PWM signal having a duty ratio of 100% when the power window 30 is opened from the rotation direction of the motor 1 determined by the control circuit 7, and the duty ratio is 0 when the power window 30 is closed. The PWM signal that gradually increases is output to the drive FET 3. This realizes a soft start in which the window glass gradually accelerates when the power window 30 is closed.
[0017]
The pinch detection circuit 11 inputs the current detection value of the current detection circuit 9, obtains the change speed of the drive current of the motor 1, and performs pinching determination by comparing with the determination value. When the pinching is determined, a pinching signal is sent to the control circuit 7. Upon receiving this signal, the control circuit 7 outputs a DOWN signal for inverting the motor 1 to the relay 2 in spite of being operated to close the power window, opens the power window for a certain time, and then again. Drive in the closing direction.
[0018]
Next, the operation principle of the above-described embodiment apparatus will be described with reference to FIG.
FIG. 2 shows changes in the signal from closing the power window 30 to occurrence of pinching, detection, and opening the power window 30.
While the P / W switch 10 raises the window glass (UP) and the power window is operated in the closing direction, the control circuit 7 outputs an UP signal to the relay 2. The soft start circuit 8 performs a soft start by outputting a PWM signal whose duty ratio gradually changes from 0 to the drive FET 3 almost simultaneously. Due to the soft start, the motor 1 is gradually accelerated, and the current detection circuit 9 detects a motor current that changes smoothly in proportion to the speed.
[0019]
Therefore, during this time, the motor current differential value obtained by the pinching detection circuit 11 falls within a certain value. The inrush current generated at the time of starting the motor is caused by the fact that the coil in the motor generates a current proportional to the inductance L of the coil and the differential value of the motor current, but the differential value of the motor current falls within a constant value. This means that the increase amount of the motor current can be suppressed by the soft start and can be made to the extent that the pinching detection accuracy is not affected. Therefore, if pinching does not occur, the amount of increase in current is kept within a certain value by soft start, so even if pinching is detected immediately after motor startup, the detection result does not include false positives, and the determination result It is not necessary to provide a period for ignoring.
[0020]
When pinching occurs, an external force that inhibits the movement acts on the power window, the driving force increases against the external force, the motor current increases rapidly, and the differential value of the motor current increases. Therefore, the differential value of the motor current can be detected by comparing with the determination value.
[0021]
When the pinching detection circuit 11 detects pinching, it outputs a pinching signal, and the control circuit 7 outputs a DOWN signal to the relay 2 regardless of whether the P / W switch is in an operation state for closing the power window 30 to output the power window. 30 is opened within a certain time. At this time, the motor reverse operation causes a more rapid current increase and the differential value of the motor current also shows a large value. However, since the power window is in an open state, the pinching detection circuit 11 does not determine pinching and does not determine the pinching signal. Do not output. This prevents malfunction when no pinching occurs.
[0022]
When the control circuit 7 finishes the inversion control, the control circuit 7 again performs control based on the operation state of the P / W switch. In the figure, since the window closing operation of the P / W switch is completed, the motor 1 is separated from the power source.
When the P / W switch 10 is operated in the direction to open the window, the control circuit 7 outputs a DOWN signal to the relay 2, and the soft start circuit 8 outputs a PWM signal with a duty ratio of 100% to the drive FET 3 to open the window. Open faster than close. At this time, the motor current and the differential value of the motor current that appear greatly are ignored as described above, and the pinching detection circuit does not perform pinching determination while the power window is being opened.
[0023]
This embodiment is configured as described above, and a drive FET is provided in the motor drive circuit, and soft start is performed when the window is closed, so that there is no sudden change in motor current. Therefore, it is not necessary to provide a detection result ignoring period for avoiding erroneous detection of pinching due to sudden changes in current. It is possible to detect pinching from the beginning when the window is closed. Since the motor is inverted by switching the relay contacts, it is possible to perform a soft start with a single drive FET.
[0024]
In addition, since the relay is always in a state of disconnecting the motor 1 from the power supply, even when the battery is reversely connected, the control circuit protected by the backflow prevention diode does not operate, so that a current flows through the parasitic diode of the drive FET. Instead, the drive FET is protected. Regarding the backflow prevention diode for protecting the control circuit, the current consumed by the circuit is very small, and even if the drive current of the relay is taken into consideration, it is about several hundred mA.
[0025]
【The invention's effect】
As described above, according to the present invention, since the connection between the DC power source and the motor is related to the operation of the control means, unless the operation to the control means is performed, the current is reversed in the motor drive circuit and the motor drive circuit Is prevented from being destroyed. In addition, when the power supply is supplied from the same DC power source as the motor using the fact that the control means operates with power supply and does not operate with a power supply with reversed polarity, the DC power supply is operated regardless of whether the control means is operated or not. The occurrence of reverse current flow in the motor drive circuit is prevented without the power source being connected to the motor. As a result, it is not necessary to provide a circuit for preventing a backflow of current in the motor drive circuit, and no heat dissipation measures are required, and the apparatus can be configured at low cost.
[0026]
When the DC power supply is connected to the motor and the motor starts, the soft start means gradually increases the drive current so that the differential value of the drive current to the motor falls within a predetermined constant value. Friction force change when an object starts moving from a stationary state can be suppressed to a low level, preventing the property change of friction force from being erroneously detected as being caught, and pinching detection can be started from the start of the motor It becomes.
[0027]
The relay means can be connected to the motor by changing the polarity of the DC power supply by control, so that the motor can be rotated forward and reverse, and the motor can be opened and closed by controlling only the motor. Can be achieved with the same motor.
Further, the entrapment detection means detects a driving current of the motor, so as compared with the determination value of the differential value of the drive current as a determination target determining entrapment of foreign object, a torque sensor for detecting an external force saving In addition, an effect of reducing the apparatus cost can be obtained.
When the foreign object is detected, when the reversal control is performed on the motor, the holding force can be suppressed to a low level and the foreign object can be pulled away from the apparatus.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing a change in a signal during operation of a power window.
FIG. 3 is a diagram showing a flow of a power supply when a power supply is reversely connected in a conventional H-bridge drive.
FIG. 4 is a diagram showing a conventional example.
FIG. 5 is a diagram illustrating a conventional example.
[Explanation of symbols]
1 Motor 2 Relay (relay means)
3 FET
4 Resistance 5 Control unit 6, 60 Diode 7, 50 Control circuit (control means)
8 Soft start circuit (soft start means)
9 Current detection circuit 10 Power window switch 11 Pinch detection circuit (Pinch detection means)
30 Power Wind

Claims (4)

In a motor control device of an opening / closing mechanism that drives an opening / closing mechanism that opens and closes an opening / closing object such as a window or a door and is supplied with power from a DC power
Control means for outputting a control signal to control the motor;
Relay means for connecting the DC power source to the motor and supplying power to the motor by a control signal output by the control means;
And soft-start means for gradually increasing the drive current as the differential value of the drive current to the motor during starting of the motor falls within a predetermined constant value,
A pinch detection means for detecting that a foreign object has been pinched by the opening / closing object by calculation from the time of starting the motor, using a differential value of the driving current of the motor as a parameter,
The motor control device for an opening / closing mechanism, wherein the control means performs control for reducing the driving force of the motor in the closing direction of the opening / closing object when the pinching detection means detects the pinching of a foreign object. 2. The motor control device for an opening / closing mechanism according to claim 1, wherein the relay unit is configured to connect the DC power source to the motor by changing a polarity according to the control signal. 3. The opening / closing mechanism according to claim 1, wherein the pinch detection means performs a pinch determination on a foreign object by differentiating the driving current of the motor and comparing the differential calculation value with a determination value. Motor control device. 4. The motor control device for an opening / closing mechanism according to claim 1, wherein the control means reversely controls the motor when the pinching detection means detects the pinching of a foreign object.

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