JPH0318397A - Detection controller for overload of sewing machine - Google Patents

Abstract

PURPOSE:To exactly detect a value (overload state) of a difference to a rating loss value of a sewing machine motor by setting a voltage value applied to the motor and a measured rotating speed as input values, deriving an overload value of the motor by a fuzzy rule generated in advance, and bringing the control of a DC motor to fuzzy inference in accordance with the overload value. CONSTITUTION:A target evaluating device 1 of a fuzzy inferring device 4 compares an operation command from a controller and a rotating speed of a control object 3, and a fuzzy inferring part 2 brings the feedback quantity of a DC motor to fuzzy inference, and controls electric energy supplied to the DC motor. The control object 3 is the DC motor, and a state X is an applied voltage and a rotating speed of the DC motor. From these data, a loss value PLos and a current value I of the DC motor are calculated, and the fuzzy inferring part 2, first of all, infers a difference PLj to a rating loss value of the DC motor by a fuzzy rule 1 from these values, and subsequently, infers a set rotation speed N of the DC motor from an accumulated value SIGMAPLj.T of the difference to the rating loss value and the current value by a fuzzy rule 2, and controls electric energy supplied to the DC motor.

Description

[Detailed description of the invention] [Industrial application field]

The present invention uses fuzzy reasoning to determine the difference between the rated loss value and the DC motor used as a sewing machine motor.
The present invention further relates to an overload detection control device for a sewing machine that infers the rotational speed to be set for the DC motor based on the cumulative value of the difference from the rated loss value and the current value, and controls the amount of power supplied to the DC motor.

[Prior art and problems to be solved by the invention] Conventionally,
There are methods for knowing the loss value of the sewing machine motor that drives the sewing machine and detecting whether it is overloaded, as shown below. l) As shown in Figure 7, in the conventional example of a built-in sewing machine, in order to know the loss value of the sewing machine motor, it is necessary to know the current value of the sewing machine motor, and this is detected by the current detection resistor R5. Ta. Here, the circuit structure will be briefly explained. In the 7th round, the volume VR1 of the controller is
It is connected to the control power supply Vcc, and the voltage changes depending on the amount of depression of the controller.
and a condenser CI,
A/D conversion terminal A/DI of chip CPU (hereinafter referred to as IC2)
The IC 2 outputs a PWM (pulse width control) signal for controlling the DC motor M according to this voltage level. The reset IC (ICI) is connected to the RESET terminal of IC2, detects the rise and fall of the control power supply Vcc, and initializes IC2. DC motor M is a sewing machine motor drive power supply vb and MOS
Connected between the drains of FET (hereinafter referred to as FETI), DC
A seven-lead wheel diode D1 is connected in parallel with the motor M. A resistor R5 is connected to the source of FETI, and this resistor R5 is a current detection resistor for the DC motor M, and has a low resistance and a high capacity as described later. The detection signal (voltage) of current detection resistor R5 is passed through a filter consisting of resistor R6 and capacitor C3 to IC2.
It is designed to be input to the A/D conversion terminal A/'D3. Further, D2 is a protection diode for preventing the input voltage to the input terminal of A/D3 from exceeding. FETI is a power MOSFET, which is a driver for switching the power supply for driving the DC motor M, and its gate 1 is connected to the gate protection resistor R4 and gate 11 of the FETI.
It is connected to IC2 via c3, and is controlled by the PWM signal output from IC2. In this embodiment, the rotation detector 10 detects the rotation speed of the DC motor using a disc slit and a photo-incrapter, and its detection signal is input to the port Pl of the IC2. Resistor R2 and resistor R3 are voltage dividing resistors for detecting the voltage of the drive power supply of DC motor M, and the voltage at the connection point between resistor R2 and resistor R3 should not exceed control power supply Vcc (5V). A/D conversion terminal A//D2 of IC2 is set.
It is connected to the. Capacitor C2 is a capacitor for filtering the divided voltage level. There is a problem in that the current detection resistor R5 must have a fairly large capacity when using a motor with large current changes such as the DC motor M3-4. That is, according to the conventional system shown in FIG.
When a current flows through the current detection resistor R5 connected in series with the motor M, the source potential of MOSFET (FETl) increases, and as a result, the gate voltage of FETI decreases relatively, causing FET1 to I can't drive anymore. Therefore, in addition to the control power supply Vcc = 5V, a higher voltage power supply, for example, a power supply of Va = 12V, is required as the gate supply power for the MOSFET. Second, the rated current of the DC motor that drives the sewing machine under normal conditions is approximately 1A, and in order to detect the current during rated operation, the If the resistance value is determined by assuming that the voltage generated across the resistor is about 1V, the resistance value of the resistor R5 will be 1Ω. However, when the sewing machine is locked, at least about 10A flows. When this sewing machine is locked, the resistor R5 has (1 0A
) 2X(1Ω) - Generates heat exceeding 100W. In the actual system, when the sewing machine locks, the power supply to the DC motor M is stopped in a short time due to the lock detection operation, so the capacitance of the resistor R5 may be a fraction of IOOOW. However, it would take up space and be wasteful to have it built into the sewing machine. 2) In addition, a method for detecting overload of a sewing machine motor using a feedback control method according to a conventional example different from 1) is described in the fifth section.
As shown in the figure, the lock detection rotation speed is set in advance for the set rotation speed, and when a load D close to the lock state is applied at time TI, this state is detected by detecting the rotation speed and the sewing machine motor is power supply had been stopped. To restart the sewing machine motor, press the controller again or
This was done by operating the start/stop button. If this operation is repeated, the sewing machine motor and drive circuit generate heat, causing failure of these parts, and in the worst case, burning out. According to the conventional example, since the lock detection rotational speed is set to a constant value with respect to the set rotational speed as described above, the sewing machine motor is operated in a slightly overloaded state as shown by loads A-C. If the sewing machine is overloaded, the condition cannot be detected, and if the machine is operated for a long time in such a condition, the sewing machine motor and drive circuit may fail, depending on the degree of overload condition, as in the case described above. It is the cause of this. In order to solve this problem, it is conceivable to attach a temperature sensor to the sewing machine motor and detect an overload condition based on whether the temperature rise of the sewing machine motor exceeds a certain specified value. In this case, it is difficult to manufacture the temperature sensor inside the sewing machine motor, and as a result, it is generally installed on the outside of the sewing machine. However, as shown in Figure 6, the difference between the temperature rise value between the outer shell and the inside of the sewing machine motor changes depending on the amount of power supplied to the motor, and also varies between sewing machine motors. It is difficult to detect temperature rise values, and there are practical problems in terms of accuracy for detecting overload conditions. [Means for Solving the Problems and Effects of the Invention] The present invention provides an electronic sewing machine that uses a DC motor to drive the upper and lower shafts of the sewing machine, in which the voltage value and rotation speed applied to the motor are input values. The difference from the rated loss value of the motor is inferred using fuzzy rules created in advance, and the rotational speed to be set for the DC motor is further inferred from the cumulative value of the difference from the rated loss value and the current value. The present invention provides an overload detection control device for a sewing machine equipped with a fuzzy inference device, and furthermore, the fuzzy inference device is configured to calculate PLj of the difference from the rated loss value based on the current value and loss value of the motor.
Inferred is the cumulative value ΣPLj4 of the difference from the rated loss value.
The present invention provides an overload detection control device for a sewing machine that infers the rotational speed to be set for the DC motor based on the current value of the DC motor and the current value of the DC motor. First, the device does not require a current detection section to detect the current of the sewing machine motor as in the conventional example, and does not use a temperature sensor to detect the amount of heat generated by the sewing machine motor. Accurately calculate the difference between the rated loss value and the sewing machine motor (
This has the effect of making it possible to detect overload conditions. Second, the rotational speed to be set for the sewing machine motor can be inferred from the cumulative value of the difference between the rated loss of the sewing machine motor and the current value, and the amount of power supplied to the sewing machine motor can be controlled.
If the sewing machine motor is slightly overloaded for a long time, lowering the set rotation speed will reduce the loss value of the sewing machine motor and prevent the motor from generating abnormal heat, resulting in the worst situation where the sewing machine is close to a locked state. If this continues, the set rotational speed will be controlled to drop rapidly and eventually stop.
In addition, in this case, if ON/OFF is repeatedly performed as in the conventional example, the cumulative value Σ of the difference from the rated loss value of the fuzzy rule
If PLj4' becomes very large and its value exceeds a certain value, the sewing machine motor will be controlled so as not to start even if a start signal is generated, which will cause the sewing machine motor and drive circuit to heat up and cause a malfunction, as in the conventional example. It has the effect of solving the problem that caused it.

【Example】

Hereinafter, the present invention will be explained with reference to Examples. ○Structure of overload detection control device for sewing machine In FIG. 1, the target evaluation device 1 of the fuzzy reasoning device 4
is a device that compares and evaluates the operating command from the controller and the rotational speed of the controlled object 3 (DC motor in this embodiment), and the fuzzy inference unit 2 compares and evaluates the rotational speed of the controlled object 3 (DC motor in this example).
This is a device that infers the amount of feedback of and controls the amount of electric power supplied to the DC motor M. In this embodiment, the controlled object 3 is the DC motor M, and the state X is the applied voltage and rotation speed of the DC motor. From these data, the loss value P of the DC motor M, which will be described later, can be calculated.
Loss and current value I are calculated, and the fuzzy inference unit 2 calculates
First, from these values, the difference PLj from the rated loss value of the DC motor M is inferred using the 7Ajii rule 1, and then the cumulative value ΣPLj of the difference from the rated loss value is inferred from the 7Ajii rule 2.
The set rotational speed N of the DC motor M is inferred from -T and the current value, and the amount of electric power supplied to the DC motor M is controlled. Next, fuzzy rules will be explained. In Figure 1, the graphs 7 shown at "Rule 1, Rule 2" are graphs of the membership functions, and the vertical axis of each graph is the membership value (from 0 to 1). membership value)
or indicate degree. ○Rule 1 The parameters on the horizontal axis of each graph in Rule 1 are loss value Plos (unit W), current value I (unit A), and difference PLj (from the left of the figure) to the rated loss value of the DC motor (
The unit is W). ○Rule 2 The parameters on the horizontal axis of each graph 7 in Rule 2 are the cumulative value ΣPLj of the difference from the rated loss value in this order from the left of the figure.
"r (unit: W), current value I (unit: A), and set rotational speed N (unit: rpm). Each of these parameters of Rule 1 and Rule 2 has a specific value on the horizontal axis of each graph. Although it has a value, it will only be shown qualitatively here.The inference is first made by calculating the current value I and the loss by the formula described later from the detected voltage value V of the DC motor M and the measured rotation speed. The difference PLj from the rated loss value of the DC motor M is inferred from the value for the smaller degree of each membership function for the value PLos.Next, the cumulative value ΣPLj-T of the difference from the rated loss value and the current value The set rotational speed N of the DC motor M is inferred from the value for the larger degree of the membership functions for , and the amount of power supplied to the DC motor is controlled. The characteristics of M will be explained with reference to Fig. 3. From the characteristic curve of DC motor M shown in the figure, the following equation is established: V-K-N・Φ+R A- I ------ ------
--(1) However, in equation (1), V: voltage K: constant N: rotational speed RA: armature resistance I; current Φ: magnetic flux. The formula for determining the current value I is obtained by transforming formula (1) into I −
(V-K-N・Φ) / RA---------(2
). Further, the loss P LOS of the DC motor M is given by the following equation. PLOS- I 2・RA + W l------
--------(3) However, in equation (3), W1 is a no-load loss Wl-D·N+WD D: Coefficient W: A loss unrelated to speed. In equation (2), the value of the constant K1 armature resistance RA is known in advance, and the magnetic flux Φ can also be known in advance once a certain range of operating conditions is determined.
If the applied voltage V is known, the current I can be determined from equation (2). In addition, in equation (3), the current value I is given by equation (2), and as mentioned above, the value of armature resistance RA is known in advance, and the coefficient D of no-load loss Wl is the loss W that is unrelated to speed. are also known in advance, so if the rotational speed N of the DC motor M and the applied voltage V are known, the loss value P Los can be determined from equation (3). 07 Overview of fuzzy control Next, an overview of fuzzy control will be briefly explained. As mentioned above, the parameters on the horizontal axis of each graph of Rule 1 are shown on the left side of the figure. In this order, the loss value Plos
(unit: W), current value I (unit: A), and difference PLj (unit: W) from the rated loss value of the DC motor M. Generally, in order to find the difference PLj from the rated loss value of the DC motor M, it is sufficient to find the loss value PLos using equation (3), and then subtract the known rated loss value from that value.
The reason why we intentionally set Rule 1 is as follows. As mentioned above, the values of armature resistance RA, magnetic flux Φ, and no-load loss W1 in equation (3) and equation (2) related to equation (3) that give the loss value P Los of DC motor M are known in advance. However, these values are so-called "average values" and vary among DC motors, and also vary depending on the operating state of the DC moke M. For this reason, the loss value P LOSN current value I is treated as ambiguous values, and a membership function whose parameters are the difference PLj between each of these values and the rated loss value as the inference result of rule l is calculated based on empirical rules and experiments. By repeating this, or by inferring the difference PIj from the rated loss value, a relatively highly accurate value can be obtained. Also, as mentioned above, the parameters on the horizontal axis of each graph of Rule 2 are, in this order from the left of the figure, the cumulative value of the difference from the rated loss value ΣPLj4' (unit: W), the current value 1 (
Unit A) indicates the set rotational speed N (unit rpm). Similarly, in Rule 2, the membership function whose parameters are the cumulative value ΣPLj - T1 current value ■ of the difference with the rated loss value and the set rotational speed N as the inference result of Rule 2 is used as a parameter. Create a function using empirical rules and repeating experiments,
By performing fuzzy inference on the set rotational speed N, a relatively highly accurate value can be obtained. The control procedure is as follows: First, the current value 1 and the loss value P Log calculated using equations (2) and (3) expressing the characteristics of the DC motor Ml5 based on the detected voltage value V of the DC motor M and the measured rotational speed. The difference PLj from the rated loss value of the DC motor is inferred from the membership function of the difference PLj from the rated loss value of the DC motor. Next, from the cumulative value ΣPLj-T of the difference with the rated loss value and the membership function for the current value ■, the membership function of the set rotational speed N of the DC motor is used to calculate the DC motor M's value. The set rotational speed N is inferred and the amount of power supplied to the DC motor M is controlled. Overload detection control of a sewing machine Next, overload detection control of a sewing machine motor according to an embodiment of the present invention will be explained with reference mainly to FIGS. 1 and 2. Unlike the conventional example, this example does not require a current detection resistor (R5 in FIG. 7), and as a result, the MOSFET
CFETI), the power supply that drives the V
Vc of the sewing machine control power supply without requiring a (usually 12V)
Since only c-5V is required, it is possible to incorporate the sewing machine's overload detection control device into the sewing machine without taking up much space compared to the conventional example. In Figure 2, when you step on controller 1/roller VRI,
The l-chip CPU (hereinafter referred to as IC2) is the controller VRI.
A/D conversion is performed on the level of , and a PMW signal (pulse width control signal) is outputted so that the DC motor M has a rotation speed corresponding to the level. In order to obtain the peak value ■P of the voltage applied to the DC motor M, IC2 converts the voltage divided by resistors R2 and R3 into A.
/D conversion and calculate a digital value with the partial pressure corrected. The applied voltage (■) of the DC motor is determined from the calculated value VP by the following formula. (See Figure 4) v-vPXTP/T
(4) However, in equation (4), TP: Pulse width (time display) T: Maximum pulse width (time display) The rotation speed (Nrpm) of the DC motor is input to the CPU via the rotation detector, and the current The value I is given by equation (2),
Further, the loss value P LOS of the DC motor M is determined by equation (3). The inference is first made based on the voltage value V of the DC motor M obtained by (4) and the measured rotational speed.
) From the value for the smaller degree of each membership function for the current value I and the loss value PLos calculated by the formula, the difference from the rated loss value PLj of the DC motor is determined by the membership function of the difference PLj from the rated loss value of the DC motor. Infer the difference PLj. Next, the setting of the D'C motor M is determined by the membership function of the set rotational speed of the DC motor M from the value corresponding to the larger degree of the cumulative value ΣPLjT of the difference from the rated loss value and the membership function for the current value ■. Rotational speed N
is inferred, and the amount of power supplied to the DC motor M is controlled. Further, when the cumulative value ΣPLj-T of the difference from the rated loss value exceeds a certain value, the sewing machine motor is controlled not to be started even if a start signal is generated. [Effects of the Invention] As described above, according to the present invention, in an electronic sewing machine that uses a DC motor to drive the upper and lower shafts of the sewing machine, firstly, current detection of the sewing machine motor is performed as in the conventional example. It does not require a current detection unit for the sewing machine motor, nor does it require a temperature sensor to detect the heat generation amount of the sewing machine motor.
This has the effect of making it possible to detect overload conditions. Second, the rotational speed to be set for the sewing machine motor can be inferred from the cumulative value of the difference from the rated loss of the sewing machine motor and the current value, and the amount of power supplied to the sewing machine motor can be controlled.
If the sewing machine motor is slightly overloaded for a long time, lowering the set rotation speed will reduce the loss value of the sewing machine motor and prevent abnormal heat generation of the motor. If the condition continues, the set rotational speed is rapidly reduced and then controlled to stop, and in this case, the rotation speed is repeatedly ○N/○ as in the conventional example.
When FF is performed, the cumulative value ΣPLj−T of the difference from the rating loss l9 of the fuzzy rule and the lost value becomes very large,
When this value exceeds a certain value, the sewing machine motor is controlled so as not to start even if a start signal is generated, which solves the problem of conventional sewing machine motors and drive circuits that generate heat and cause malfunctions. Effects can be obtained.

[Brief explanation of the drawing]

1 to 4 relate to embodiments of the present invention, FIG. 1 is a block diagram showing a 77J inference device for overload detection control of a sewing machine, and FIG. A block diagram of the detection control circuit, Figure 3 is a diagram showing the characteristics of the DC motor, Figure 4 is a diagram explaining how to determine the applied voltage in PWM control, and Figure 5 is the actual rotation speed and lock in each load state. Figure 6 is a diagram showing the relationship between the detected rotational speed, etc., Figure 6 is a diagram showing the relationship between the temperature rise between the inside and the outer shell of the sewing machine motor, and Figure 7 is the overload detection control of the sewing machine built into the conventional sewing machine. It is a block diagram of a circuit. 4 is the fuzzy inference device, ■ is the current value, M is the DC201 mode, N is the set rotation speed, P Los is the loss value, PL
j is the difference from the rated loss value, ΣPLj4'' is the cumulative value of the difference from the rated loss value, and ■ is the voltage value.

Claims (1)

[Claims] I. In an electronic sewing machine that uses a DC motor to drive the upper and lower shafts of the sewing machine, a voltage value V applied to the motor;
The present invention is equipped with a fuzzy inference device that calculates the overload value of the motor using a fuzzy rule created in advance using and the measured rotational speed as input values, and fuzzy infers the control of the DC motor according to the overload value. Features: Sewing machine overload detection control device. II. The fuzzy rules of the fuzzy inference device infer the difference PLj from the rated loss value from the current value I of the motor and the loss value PLos, and further calculate the cumulative value Σ of the difference from the rated loss value.
2. The overload detection control device for a sewing machine according to claim 1, wherein a set rotational speed of the DC motor is inferred from PLj·T and a current value I of the DC motor.