JPS58148692A - Torque setting device for motor - Google Patents

Abstract

PURPOSE:To always output an accurate control signal by detecting the torque of a motor in the state of no load or near the no load, comparing and calculating the signal representing the magnitude of the torque with a reference signal and setting the other reference value. CONSTITUTION:In, for example, a vehicle washing machine, torque sensors 6a, 6b which detects the torques of washing brush drive motors 5a, 5b are provided in the motors. The outputs of the sensors 6a, 6b are applied to an arithmetic controller 10. The controller 10 stores reference voltages corresponding to the motor torques in response to the positions A, B of the washing brushes 2a, 2b, and outputs a sequence control signal which performs the prescribed mechanical operation when the output voltages of the sensors 6a, 6b exceeds the above reference voltages. The controller 10 compares the output signals of the sensors 6a, 6b with the other reference signals according to the magnitude of the output signals of the sensors, and controls the torques of the motors 5a, 5b. The reference values are corrected by the motor torques at no load or in the vicinity of the no load, and an accrate control signal can be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a torque setting device for an electric motor.

For example, in a car washing apparatus for a car, after the brushes are brought close to each other at point B in FIG. 1, the trolley 3 is moved to bring the brush into contact with the car 1 at six points, and the car wash is started.

As a sequence control device for moving the brushes as described above, the torque of the brush electric motor that drives the car wash brush is detected by a torque sensor, and the torque sensor output voltage is
When the reference value EA in the figure is reached, a control signal indicating that the car wash brushes are at point A in Fig. 1 is output, the car wash brushes are advanced in the direction B, and when the car wash brushes come into contact with each other at point B, the electric motor is activated. It has been proposed that when the torque increases and the output voltage exceeds EB, a control signal indicating that the motor is at point B is output.

The above-mentioned torque sensor is, for example, one in which a core is placed at the coil end of the primary winding of an induction motor so that it can be electromagnetically coupled, and a signal proportional to the torque is obtained by the winding wound around the core. may be used.

As shown in Figure 3, this rice torque sensor tends to have a large error ER in a range where the motor torque is small.
For example, in a low torque range such as point A or point B in FIG. 1, even if the reference value EA is reached.

Even if EB is set, there is a drawback that point A and point B may be detected incorrectly due to an error in the output of the torque sensor.

In addition, when obtaining a sequence control signal based on the magnitude of the motor torque, if the no-load loss increases due to changes in the mechanical load, such as changes in the axis of the car wash brush connected to the motor, the torque sensor shown in Figure 2. Since the output characteristic curve moves upward, for example, in Fig. 1, the output voltage of the torque sensor reaches E before the car wash brush reaches point B.
B is reached and the control signal is output at the wrong position.

Furthermore, the control signal may be output at the wrong position due to fluctuations in the torque detection voltage due to variations in the torque sensor itself or variations in the characteristics of the electric motor that drives car wash brushes and other mechanical loads. There is also the disadvantage that

This invention was made to eliminate the above-mentioned drawbacks, and it reads the torque sensor output under no load or near no load and sets other reference values based on this. An object of the present invention is to provide a torque setting device for an electric motor that can always output accurate control signals regardless of errors, fluctuations in mechanical load loss, and product variations. I will explain it together.

FIG. 4 is a diagram showing an example in which the present invention is applied to a car wash apparatus similar to that shown in FIG. 1, and components equivalent to those in FIG. 1 are given the same reference numerals.

In FIG. 4, reference numerals 5a and 5b are car wash brush driving motors using squirrel cage induction motors, and torque sensors 6a and 6b for detecting the torque of each motor are provided inside the motors.

For example, as shown in FIG. 5, the torque sensors 6a and 6b sandwich the coil end 7 of the squirrel-cage winding of the induction motor 5 between the iron cores 8, and are wound around the iron cores 8! I9 is provided to obtain a voltage proportional to the motor torque from the winding 9. Note that in the present invention, other arbitrary types of torque sensors may be used.

Reference numeral 10 denotes a calculation-side m-device using a microcomputer, to which the output signals of the torque sensors 5a and 6b are applied. Inside the arithmetic and control unit 10, there are positions A of the car wash brushes 2a and 2b in FIG.

Reference voltages EA, EB, EC, . The data are compared within the arithmetic and control unit 10. Then, the arithmetic and control unit 10 sets the torque sensor voltage to each reference value EA, E.
When B, EC, etc. are exceeded, a sequence control signal is output to perform a predetermined mechanical operation.

Further, the arithmetic and control device 10 outputs a signal for controlling the torque of the electric motors 5a, 5b according to the magnitude of the output signal of the torque sensors 5a, 5b, based on a signal as a result of comparison with a reference voltage ED, etc. In addition, 11°12 is the car wash brush 2a
, 2b.

In the present invention, the reference value EA1EB1EC is not a fixed value, but is modified based on the motor torque at or near no-load. That is, the output of 6b is read, and the output voltage EA' of the torque sensor at this time is stored in the arithmetic and control unit IO. Then, values α and β corresponding to a predetermined torque increase are added to the voltage EA' of the torque sensor, and other reference voltages EB' and EC corresponding to the motor torque at points B and 6 are calculated by the following equation: EB = EA '+αEC=
Determined by EA'+β.

The same applies to other reference values ED and EE (EE>ED>EC).

Therefore, at the start of the first operation, the output of the torque sensor 6λ indicating the actual torque of the electric motor 5a when the car wash buoys V2a and 2b are at point A - voltage EAI
is read by the arithmetic and control unit 10, and based on this read value, the reference voltage EB1 corresponding to point B is determined as EB.
It is set as l=EAI+α. Similarly, the reference voltage E c 1 corresponding to the 0 point is E. □-E
It is set as A1+β. Then, during the first car wash, the reference voltages Esi and Ecl are compared with the output voltage of the torque sensor 6a, and control is performed according to the comparison result.

Further, during the nth car wash operation, the output voltage EAo of the torque sensor 6a, which indicates the actual torque of the electric motor 5a when the brush is at point A, is read by the accounting control device 1°.
As shown in Figure 6, point B and 0 during the nth operation
The reference voltages corresponding to the points are EBn-EAn+α, Ecn-
It is set as EAn+β. And this reference voltage E
Bn + ECn is compared with the output voltage of the torque sensor 6a, and sequence control is performed according to the comparison result. A similar operation is performed for the torque sensor 6b.

Therefore, during the first operation, the motor torque at point B in FIG. Even if the torque at light load increases and the motor torque at point B, which is the first factor, changes to Tn, the reference voltage EB□ for detecting point B has also changed to EBn, so the torque sensor voltage At the time E B1 , that is, before the car wash brush reaches point B, a control signal erroneously indicating that the brush is at point B will not be generated. Note that a control signal is obtained when the torque sensor voltage exceeds the newly set reference voltage EBn, that is, when the car wash brush reaches point B, which is the first factor.

Even if there is an error in the torque sensor output voltage during low-torque operation due to variations in torque sensor products, the reference voltages EB, EC, etc. are corrected in the same way as described above, and the accurate position of the car wash brush can be determined. The control signal shown is obtained.

Note that the present invention is applicable not only to car wash brushes but also to any control system torque detection device that obtains a sequence control signal from the torque of an electric motor.

Further, the torque sensor is not limited to the type shown in FIG.

Furthermore, in the above-described embodiment, various reference voltages are calculated based on the output voltage of the torque sensor at point A in FIG. Other reference voltages may be modified based on the output voltage.

As detailed above, according to the present invention, in a control system that obtains a control signal by comparing the output value of a torque sensor of an electric motor with a predetermined reference value, Because the system reads the torque sensor output at the same time and sets other reference values based on this, it is possible to always output an accurate control signal even if there is an error in the torque sensor output or fluctuations in the load torque. You will be able to do this.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of a car wash device, Fig. 2 is a graph showing the relationship between electric motor torque and torque sensor output, and Fig. 3 is a plan view showing an example of a car washing device.
The figure is a graph showing a state in which an error occurs in a torque sensor, FIG. 4 is a block diagram showing an embodiment of the present invention, FIG. 5 is a sectional view showing an example of a torque sensor, and FIG. 6 is an implementation of the method shown in FIG. It is a graph showing an example operation. 5a, 5b...Electric motor, 6a, 5b...Torque sensor, 10...Arithmetic and control device Patent applicant: Fuji Electric Manufacturing Co., Ltd. Representative Patent Attorney Aoyama, 2 people → Figure 3 Figure 4 Figure 5 ^ Figure 6

Claims (1)

[Claims] (1) A torque detection means that detects the torque of the electric motor and generates a signal representing the magnitude of the torque, and compares the output signal of the torque detection means with a predetermined reference value, and outputs a control signal according to the comparison result. An electric motor characterized in that it is equipped with a calculation means for outputting an output, and a setting means for reading the output voltage of the torque detection means under no load or near no load, and setting other reference values based on this. torque setting device.