JPH03143284A - Circuit for controlling switching element driving motor - Google Patents

Abstract

PURPOSE:To enhance the reliability of detecting a malfunction by judging the motor to be in an overload state when the ratio of decrease in rotating speed of the motor to a reference value set by arbitrarily reading and storing the signal of rotating speed sensing means exceeds a predetermined value, and reversing or stopping the motor. CONSTITUTION:A CPU 2 outputs a drive command signal to a motor 4 in response to the opening/closing state of the contacts of switches. In the case of continuously opening operation, a pulse output is counted, the position of a sunroof panel is stored, and the rotating speed of the motor 4 is estimated from the pulse period. When the overload state of the motor 4 is sensed from the pulse period, a drive command output to the motor 4 is stopped. Even when the panel is fully opened, the overload state of the motor 4 is sensed to stop the drive command output. Thus, the motor can be rapidly reversed or stopped for a small malfunction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a control circuit for an electric motor that drives an opening/closing member such as an automobile sunroof or a power window.

<Prior art> For opening/closing bodies that are driven to open and close by electric motors, such as electric sunroofs or power windows,
It is preferable to add a safety function such that the electric motor reverses or stops when a foreign object is caught during its operation (particularly during its closing operation). Such security functions include:
It detects the load current of the motor and reads from changes in the frequency or period of the pulse signal as the motor rotates to indicate that the driving load of the opening/closing body has increased to a predetermined value or more, and based on this, controls the reversal or stop of the motor. What has been done is known.

<Problem to be Solved by the Invention> However, since the load current and rotational speed of a motor may change significantly due to temperature changes and voltage changes, it is necessary to uniquely define a reference value for determining an overload state. cannot be controlled. Therefore, a control system may be adopted in which the frequency or cycle is read at any time and the motor is reversed or stopped when the rate of change from the previous value exceeds a predetermined value. However, this method has the disadvantage that if the rate of change is slow, it is difficult to detect an abnormality.

The present invention was devised to eliminate such inconveniences, and its main purpose is to provide a control circuit for a switchgear drive motor that is improved in order to increase the accuracy of abnormality detection.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the object is to provide a control circuit for an electric motor for driving an opening/closing body to open/close in response to an operation signal of an operation switch, which comprises: It has a signal detection means for detecting a signal corresponding to the rotational speed of the electric motor, and each time a signal indicating a rotational speed higher than a set reference value is input by reading and storing the signal of the signal detection means from time to time. The setting of the reference value is updated, and when the rotational speed reduction rate of the electric motor with respect to the reference value exceeds a predetermined value, it is determined that the electric motor is in an overload state, and the electric motor is controlled to reverse or stop. This is achieved by providing a control circuit for an opening/closing body drive motor characterized by the following.

According to this configuration, the reference value for determining whether the motor is overloaded changes in accordance with the steady operating speed of the motor depending on the temperature or voltage at that time, making it easy to determine the overload state. can be performed properly at all times. Furthermore, since the value corresponding to the maximum rotational speed in the operating cycle becomes the reference value, the accuracy of abnormality determination is increased. Moreover, since the overload is determined based on the rate of change with respect to the reference rotational speed, an appropriate overload determination can be made even if the steady-state operating level changes.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the entire control circuit of a vehicle sunroof device as an opening/closing body to which the present invention is applied. This control circuit 1 includes a CPU 2 that controls the entire operation, a contact output group 3 of each switch (described later) that provides the CPU with information regarding the operation status and operating status of the sunroof panel (not shown), and a group of contact outputs 3 for opening and closing the sunroof panel. Driving electric motor 4
and a rotation direction setting circuit 5 that selects and sets the forward or reverse rotation direction of the motor 4 using an electromagnetic relay driven by a control signal from the CPU 2.

The contact output group 3 includes a 4-motion open switch 6, a continuous open switch 7, a 4-motion close switch 8, a continuous close switch 9, and a tilt switch for giving the sunroof panel opening/closing motion in 4-motion operation or continuous operation. A tilt up switch 10 for providing operation, a close limit switch 11 and a lower limit limit switch 12 for detecting the operating limit of the sunroof panel, and generate pulse signals in synchronization with the rotation of the electric motor 4. The rotation sensor 13 outputs a signal corresponding to the rotation speed of the sunroof panel and a position detection signal of the sunroof panel to the CPU 2.

The CPU 2 includes lock signal generation circuits 1 and 4 that can be selectively oscillated/stopped by the CPU 2, and the operating state of the CPU 2 is monitored using a pulse signal oscillated by the CPU 2. If it is determined that there is an abnormality, a signal is sent to the CPU 2. a watchdog timer circuit 15 as a monitoring circuit that outputs a program and pulse oscillation reset signal; and a watchdog timer circuit 15 that clears the memory contents in the CPU 2 when power is switched from not being supplied to the CPU 2 to being supplied. A clear signal output circuit 16 and a reset signal output circuit that reset the program in the CPU 2 and the pulse oscillation to the watchdog timer circuit 15 when the power to the CPU 2 changes from not being supplied to being supplied. j circuits 17 are respectively connected.

Power is constantly supplied to the CPU 2 from the vehicle battery 19 via the stabilized power supply circuit 18 .

Further, the on/off signal of the ignition key switch 20 is given to the CPU 2 via the buffer 21, and is sent to the watchdog timer circuit 15 via the switching circuit 22 which is turned on when the ignition key switch 20 is turned on. Stabilized power supply circuit 18
Power is supplied from

Next, the operation procedure of the above embodiment will be explained.

To open and close the sunroof panel, each switch may be operated as desired. That is, the CPU 2 outputs a drive command signal to the electric motor 4 according to the open/close status of the contacts of each switch. In the case of continuous open operation, the pulse output is counted to store the position of the sunroof panel, and the rotational speed of the electric motor 4 is determined from the pulse period.

If an overload condition of the electric motor 4 is detected from this pulse period, the drive command output to the electric motor 4 is stopped. Even when the sunroof panel reaches the fully open position, the overload condition of the electric motor 4 is detected and the drive command output is stopped.

In the case of four-motion operation, an open or close command signal is output to the motor 4 only while the switch is pressed. In this case as well, detecting an overload on the motor 4 from the pulse period is performed in the same way as in continuous operation, but if an overload condition is determined, control is performed to disable the previous operation. .

Tilt operation occurs when the sunroof panel is in the fully closed position.
That is, it is made effective only when the signal from the close limit switch 11 is input to the CPU 2. The tilt-up operation is performed by a dedicated tilt-up switch 10, the tilt-down operation is performed by a continuous close switch 8, and the completion of tilt-down is performed by a contact signal from a lower limit detection limit switch 12. That is, two limit switches 11.・Identified from 12 states.

Next, the safety return operation routine of the sunroof panel will be explained with reference to FIGS. 2 and 3.

In step ST1, a close command signal is output to the rotation direction setting circuit 5 in response to the operation of the continuous close switch 9, and the electric motor 4 is started in the close direction. Next, the rotation speed n of the electric motor 4 is determined from the output of the rotation sensor 13. Period value T for several pulses synchronized with . is detected in step ST2, and this value is stored as a load determination reference value. still,
Considering that the rotation is unstable immediately after starting the electric motor 4, data on the rotation speed is not captured for a predetermined period of time (section tm in Figure 3), but since the rotation speed tends to increase, , this time should be extremely short.

Next, after a predetermined period of time has passed from step ST2, step ST
3, detect the pulse signal corresponding to the rotation speed n1 again,
Find the period value T. Then, in step ST4, this value T
and the lower price that is remembered. It is determined whether the ratio of T to To is greater than or equal to a predetermined reference value (for example, 140%).

Here, if it is determined that the rate of decrease in the rotational speed of the electric motor 4 exceeds a predetermined value, that is, the period T has increased beyond a certain limit, as shown by n4 in FIG. In step ST5, the electric motor 4 is assumed to be in an overload state, and the sunroof panel is reversed by a predetermined distance and then stopped.

On the other hand, T in step ST4. If it is determined that the ratio of T to T is equal to or less than a predetermined reference value, that is, the electric motor 4 is in a steady operating state, the ratio is equal to or less than the cycle value stored in step ST6. and the current cycle value T. T here. >T, that is, if it is determined that the motor rotational speed is increasing (n, n3 in Figure 3), the new value of T is set to T. In other words, the overload determination reference value is updated, and if To≦T, that is, the rotation speed is fluctuating to a low value (n2 in FIG. 3), T.

The process returns to step ST3 without updating the value of . In this way, the overload determination reference value is always set to a smaller value.

If some foreign object is caught in the drive section of the sunroof panel, the load on the motor increases, but the rotational speed of the motor 4 slows down and the pulse period T becomes longer.

Therefore, by comparing the cycle value T detected at regular intervals in the above routine with the minimum cycle value To during that cycle, it is possible to accurately determine whether the motor 4 is overloaded. Then, when normal operation continues and the sunroof panel position determined from the pulse integrated value reaches the predetermined position immediately before fully closed (point A in Figure 3), load detection is canceled and the close limit switch 11 is pressed to fully close the sunroof panel. The motor 4 continues to operate until the closed state is detected (point B in Figure 3) (section tc in Figure 3).

In the above routine, only the closing operation was explained, but the opening operation can be performed in the same way. Further, as for the overload judgment value, it is also possible to appropriately change different values between the four movements or between open and close.

[Effects of the Invention] As described above, according to the invention, the overload detection level of the electric motor during the opening/closing operation can be determined without being influenced by the temperature conditions or battery voltage at that time. Further, even if some load fluctuation occurs during operation, the value under the lightest load condition is determined as the reference, so the electric motor can be quickly reversed or stopped even in the event of a slight abnormality. Furthermore, since overload is determined based on the rate of change with respect to the reference rotational speed, it is possible to appropriately determine overload even if the steady-state operating level changes. Therefore, an extremely large effect can be achieved in increasing the accuracy of overload determination in the opening/closing member drive motor. In addition, since the structure can be simplified without using a clutch mechanism or a circuit breaker, it is effective in reducing manufacturing costs and downsizing the device.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a control circuit of a sunroof device to which the present invention is applied, FIG. 2 is a control flow diagram of the portion related to the present invention, and FIG. This is a graph for explanation. 1...Control circuit 2...CPU3...Contact output group 4...Electric motor 5...Rotation direction setting circuit 6...4-motion open switch 1 7...Continuous open switch 8... 4-motion close switch 9... Continuous close switch 10... Tilt up switch 11... Close limit switch 12... Down limit limit switch 13... Rotation sensor 14... Clock signal generation circuit 15. ... Watchdog timer circuit 16 ... Clear signal output circuit 17 ... Reset signal output circuit 18 ... One stabilized power supply circuit ... Vehicle battery 20 ... Ignition key switch 21 ... Buffer 22 ...For switching circuits Applicant: Representative of Mitsuba Electric Co., Ltd. Patent attorney: Yo Oshima 2

Claims (1)

[Claims] (1) A control circuit for an electric motor for driving the opening/closing body to open and close in response to an operation signal from an operation switch, comprising a signal detection means for detecting a signal corresponding to the rotational speed of the electric motor, the signal detection means The setting of the reference value is updated every time a signal indicating a rotation speed higher than the set reference value is input by reading and storing the signal from time to time, and the rotation speed reduction rate of the electric motor with respect to the reference value is set to a predetermined value. 1. A control circuit for an opening/closing body drive motor, characterized in that when a value exceeds a value, the motor is determined to be in an overload state, and the motor is controlled to be reversed or stopped.