JPS6289495A - Torque controller for differential actuator - Google Patents

Abstract

PURPOSE:To increase the range of a torque control from zero speed of an output shaft to a normal rotating speed range by inverter-controlling independently a differential mechanism and two induction machines respectively. CONSTITUTION:Induction machines 1, 2 form together with a differential mechanism 3 a differential actuator 4. The machines 1, 2 are driven by the powers from inverters 8, 9 through peculiar distribution lines 6, 7 from the same 3-phase AC power source 5. A digital torque detector 11 is attached to the output shaft 10 of the actuator 4, and the detected torque value is indicated on a torque meter 12. When the input frequency of the inverter input to the machines is arbitrarily set, the rotating direction of the output shaft is reversely rotated, or the torque of desired magnitude can be freely obtained.

Description

[Detailed Description of the Invention] [Field of Application] This invention relates to a 6-stroke motor consisting of two induction motors and a differential mechanism.
Regarding the torque control system of 7'chi'-2 output 1'''control'6 difference 4Y-; Kuchi, 1 motor.

[Conventional technology]

Figure 9 is based on the inverter of an induction machine used as a conventional actuator! lj control circuit diagram.

In the figure, 51 is an input terminal of the AC source, 52 is an AC-DC converter that converts AC to DC, 53 is a smoothing circuit that completely smoothes the DC current, and 54 is a smoothing circuit that converts DC to any frequency. A current-to-AC converter (hereinafter referred to as an inverter) that converts into AC power, 55 is an induction machine.

Next, the operation will be explained.

First, the AC-11-current converter 52 converts, for example, a 3-phase AC power supply into DC 1 (7). After smoothing this in the smoothing circuit 53, the inverter 5 turns on and off in a certain sequence.
4, the signal is converted into an AC power IF of any desired frequency, and this is input to the conductor 55. Second, the rotational speed of the induction machine 55 is controlled by receiving the voltage/frequency output from the inverter 54 as shown in FIG.

Furthermore, by using the inverter 54fc as described above and changing the voltage/frequency characteristic (V/f characteristic), that is, by making the output voltage V proportional to the output frequency f of the inverter 54, the almost constant torque characteristic can be obtained. It's gone, it's 1, frequency f
If the voltage V is controlled to be constant even when V changes, approximately constant output characteristics can be obtained.

[Problem that the invention seeks to solve]

The conventional control method using an inverter for an induction motor is as described above, and as shown in Fig. 11, torque control is possible except in the low speed rotation region, but it is possible to control the torque from 1 to 1 in normal operating conditions. In the low rotational speed region around this area, Vi,
) The torque ripple becomes large, making it impossible to obtain sufficient and stable torque.Therefore, there are problems in that it is impossible to control the torque of the induction motor in this rotational speed range.

This invention was made to solve all of the above problems, and uses an inverter to control a differential actuator that combines two induction motors and a differential mechanism, thereby increasing the output shaft from zero speed to normal rotation speed. The object of the present invention is to obtain a torque control system for a differential actuator that can output a sufficiently large torque over a range of areas.

[Means for solving problems]

The torque control method for a differential actuator according to the present invention uses each of the above-mentioned induction machines of a differential actuator consisting of two induction machines and a differential mechanism, and inverters provided correspondingly thereto. The drive is controlled.

[For production]

In this invention, one induction machine is driven by an inverter with a constant output frequency, and the other induction machine is driven by an inverter that can select any output frequency. It acts to obtain constant torque throughout. This is due to the differential characteristics of the differential mechanism that allows the output shaft to be driven at zero speed even when each of the induction machines rotates at high speed, and at the same time prevents the occurrence of torque ripple. Furthermore, by arbitrarily setting the output frequency of the inverter input to each induction machine, it is possible to reverse the direction of rotation of the output shaft and to freely obtain a desired amount of torque.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained. 1st
In the figure, reference numeral 1.2 indicates an induction machine having the same output characteristics and the same structure, and these constitute a differential actuator 4 together with a differential mechanism 3, which will be described later.

The induction machines 1 and 2 receive power from the same three-phase AC power supply 5 via their own distribution lines 6 and 7. Here, the voltage/frequency characteristics shown in FIG. It is driven by receiving power from each inverter 8.9. 10 is an output shaft of the differential actuator 4, and a digital torque detector 11 is attached to this, so that the detected torque value can be displayed on a torque meter 12.

The data detected and measured by the digital torque detector 11 and other circuit current, voltage, and power measuring instruments can be monitored at any time on a display device such as a control panel. Also, 13°14 is
This is a polyphase power needle inserted into the

FIG. 2 is a structural diagram showing details of the differential actuator 4. As shown in FIG. In the figure, reference numerals 1 and 2 indicate induction machines, which are connected by a differential mechanism 3 and housed in the same case 21. Reference numerals 22 and 23 denote hollow rotating shafts of the induction machines 1 and 2, which are rotatably supported by bearings 24 and 25, respectively.

26.27 are the first . A second differential gear, 28.29, is a third differential gear, 3, meshed together with both differential gears 26.27.
0 is a differential shaft installed on the third differential gear 28 and 29, 31 is a differential bearing that rotatably supports this differential shaft 30, and 32 and 33 are orthogonal to the differential shaft 30. Projecting output shafts pass through the hollow rotating shaft 22.23 and are rotatably supported by bearings 34.35 provided at the open end of the case 21.

Next, the operation of this differential actuator 4 will be described, and then the method of the present invention will be described according to the circuit shown in FIG.

First, the rotating shafts 22 and 23 move toward the differential mechanism 3 by arrows P,
When rotating in the Q direction, if the rotational speed θ1 of the rotating shaft 22 is greater than the rotational speed θ2 of the rotating shaft 230, (θ1
〉θ2) Based on these rotational speed differences, the third differential gears 28 and 29 rotate on their own axis around the differential shaft 30 while moving over the first differential gear 26 and the second differential gear 27. revolve. Therefore, the outputs 41132, 33 are outputted via the differential shaft 30.
rotates in the R direction, and its rotational speed is θ0 =-(θ1-02) ・・・・・・・・・
It becomes fi1. Furthermore, if the rotational speed of the rotating shaft 22 is lower than the rotational speed of the rotary shaft 23, that is, θ1 < θ2, then the 30th differential gear 28, 29 will receive 270 rotations of the second differential gear. The output shaft 32.33 rotates on the first differential gear 26, 27 in the opposite direction to that described above, and the output shaft 32, 33 rotates in the opposite direction. Next, if the rotational speeds of the rotating shafts 22 and 23 are both equal (θ1-θ2), then θ0-0, and the difference in the rotational speeds of the output shafts 32 and 33 becomes zero, that is, they stop.

In this way, even if the two rotating shafts 32, 33 are used within the normal rotation speed range, the output shafts 32, 33 can smoothly and easily rotate from zero speed to a predetermined low speed. In other words, it becomes easy to shift gears in a low speed rotation region.

Next, when the rotational direction of one of the two rotational shafts 22.23, for example the rotational shaft 23, is reversed (in the direction of arrow S), the rotational speed of the output shaft 32.33 at this time will be the first. The rotational speeds of the 20th differential gears 26 and 27 are added together, and θ0 = - (θ1 + 02)...
... T2), and the speed will be increased. Also, the rotational speed θ1. If both θ2 are equal, then (θ1=0
2), the third differential gear 28.29 is connected to the first differential gear 28.29. It is on the 20th differential gear 26, 27 and does not rotate, and the 1st. The output shaft 3 rotates integrally with the second differential gear 26, 27, and is obtained at this time.
The rotation speed of 2.33 is constant with the rotation axis 22°23,
And the output will be equivalent to the output of induction machines 11 and 12.

In other words, the speed change range of the output shaft of the differential actuator 4 is a wide range including all zero speeds.

On the other hand, if each output torque of the induction machine 11.12 is T11T2, and the output torque of the output shaft 32.33 is To, there is always To == Ts + T2 between them.
・・・・・・・・・・・・The relationship (4) is established, and the output torque T1. If T2 is in equilibrium, To=2
T, and a sufficiently large torque can be obtained on the output shaft 32,33.

Next, a method of controlling the differential actuator 40 torque 1- using the [61 path shown in FIG. 1] will be described.

First, the relationship between the rotational speed of the output shafts 32 and 33 of the differential actuator 4 and the torque is determined by setting the set frequencies of the inverters 8 and 9 to 35HE and 30Hz, respectively (frequency difference 5Hz), and the rotation of the induction motor 1.2. Speed 937 RPM
When determined through experiments, the result is as shown by the solid line in Figure 3, and the maximum generated torque reaches 29.6 Kym, which is the maximum torque shown by the dotted line when a single induction motor is driven at the set frequency as in the past. Compared to the generated torque 4.7 to 9cnb,
Become big enough.

This means that by controlling the differential actuator 4 in an impact manner, a sufficiently strong torque can be generated even in a low rotational speed range, making it sufficiently practical.

In addition, the set frequency of inverter 8 is fixed at 35Hz,
Change the set frequency of the other inverter 9 from 5Hz to 30Hz
When changing the torque between -
The rotation speed characteristics are obtained and the droop characteristics are similar to those of a DC machine.

In other words, all you have to do is set a sufficiently large amount of the associated control ratio. According to this, for each set frequency to be changed, a sufficiently large torque can be obtained by controlling a small number of rotations, and in a differential actuator that is a combination of two DC machines, the difference in voltage applied to each DC machine can be It also corresponds to cases where it is changed.

Next, the output i! 1132.33 (ζj nib L・'
- By applying a load with a key etc., the set frequency of the inverter 8 is set to a constant 35Iim, and the set frequency of the inverter 9 is changed.
．． The torque-rotational speed characteristic 6 of the 33 is as shown in FIG. 5, and the torque can be controlled to be almost constant regardless of the same rotational speed.

In this way, the output shaft 3 of the differential frequency 1 type acticoator 4
2, 33 AX low] -ir rotation 1-,, -r a2.
The field, Ctr'4, constitutes 5, and the induced state 1,
2ζ・, length high speed -te rotation 1r, output shaft 3
2, 'ti 3 is II (at high speed rotation), ・l',
Also, the torque generated by the driver is -16 τ, and the torque ripple is also extremely small.

Figure 6 shows the use of the top control system invented by ζ''1-
This is the difference! Formed by the output shaft 33 of type I1 Akuzayu, -ta 4, 'lr threaded part 33
Horizontal movement 111' with threaded I7 at a i *1) Nut member 4 i,, I:: , this nut member 41 - end metal pivot j2, two one γ-me 42, and one end is pivotally supported on the case-1 on the induction machine 2 side, and the other end of the arm 42 is pivotably supported in the center.A grip arm 43 and a grip arm 43 are arranged opposite to each other at the ends of the grip arm 43-f1. ．． It is composed of a grip plate 44 with a protruding L ridge. This gripper is a differential type actuator 2 to actuator 4 as described above.
The torque control allows the workpiece 452 to be clamped between the grip plate 44 with any force, making it possible to grip even the softest workpiece 45 without damaging it. For example, if the moving speed of the workpiece 45 (/(i) is 1.With a constant clamping force,
5 can be changed from one force to the other. .

No. '71'' 4it↓1..7H-ri control method purple usage 1.
．． fJ-, 5565 with 7-way extrusion equipment of various automatic machines
．． This is the output of the differential actuator 1--4.
A horizontally movable V-knot member 46 is screwed onto the threaded portion 33&.

The nut member 46 and the KI-shaped extruded rod 47 are integrated into one
19. from the one attached to f54. As the output shaft 33 rotates, the extrusion rod 47 pushes the workpiece 48 toward the top of the bed 49. It works like this. According to this.

For example, work 433 presses 1. When taking it out, slowly apply high torque 5 When returning to the original position, quickly shake the small tonneau 1. It can also be operated with a constant torque V.

FIG. 8 shows a clamper 1-7 using a torque control type. This means that the output shaft 33 of the differential actuator 4 is equipped with an arm 50, and a workpiece 51 is attached to the end of this arm 50.
The clamping member 52 is pivoted to clamp the clamp member 52, and the torque 1ltIII described above is applied.

The clamping force of the clamping member 52 against the workpiece 51 can be constant or arbitrarily controlled.

〔Effect of the invention〕

As described above, according to the present invention, the two induction machines that constitute the differential actuator together with the differential mechanism are each independently controlled by the inverter, so that the output shaft can be controlled from zero speed to the normal rotation speed range. , the range of torque control can be expanded, and stable torque can be obtained easily and at any time.

[Brief explanation of drawings]

FIG. 1 is a block connection diagram for explaining a torque control method of a differential actuator according to an embodiment of the present invention;
Figure 2 is a cross-sectional view of the differential actuator, Figure 3 is a torque-same rotation characteristic diagram of the differential actuator, and Figure 4 is the torque of the differential actuator when the set frequency of the inverter is changed. - Rotation speed characteristic diagram, Figure 5 is the same i. Lecoux rotation speed characteristic diagram when a load is applied to the output shaft, Figure 6 is a front view of the gripper using the torque control method, and Figure 7 is also a workpiece extrusion diagram. The front view of the device, Figure 8 is a front view of the clamper, Figure 9 is a circuit diagram of a conventional induction machine controlled by an inverter, Figure 10 is a voltage/frequency characteristic diagram of the inverter, and Figure 11 is a diagram of a conventional induction machine. It is a torque-rotation speed characteristic diagram of the machine. 1.2 is an induction machine, 3 is a differential mechanism, 4 is a differential actuator, and 8.9 is an input/(-ta).In addition, the same reference numerals indicate the same or corresponding parts in the figure.Patent applicant Mao Naotake Ri Patent applicant Mitsubishi Electric Corporation 1'- Agent Patent attorney 1) Hiroshi Sawa; (2 others) "-11 Fig. 1 Fig. 2 Plate rotation speed Fig. 5〈- j→ (・Procedural amendment) (Voluntary) 1. Chugai indication 9.'j Application 1986-227231
issue? 1 Name of the invention Torque control system for differential actuator, '3. Relationship between the person making the amendment and the tenancy: Representative of the applicant for permission: Mamoru Shiki, late 4, Agent: Postal code: 105 Address:
East J; ζ 1-4-10-5 Nishishinbashi, Minato-ku, Target of correction 6, Mi positive inner world Figure 1 will be corrected as shown in the attached sheet. At least one document containing Figure 1 after 11 minutes of cataloging of imposed documents

Claims (2)

[Claims] (1) Equipped with two induction machines and a differential mechanism that extracts the sum or difference of the rotational speeds of each of these induction machines and transmits it to the output shaft, and according to the rotational speed of each of the induction machines. In the torque control method of the differential actuator that controls the torque of the output shaft, each of the induction machines is driven and controlled by a unique inverter having the same or different voltage/frequency output characteristics. A torque control method for differential actuators featuring: (2) By inputting a constant frequency signal to one induction machine and a variable frequency signal to the other induction machine,
2. The torque control system for a differential actuator according to claim 1, wherein the torque obtained at the output shaft is controlled to be constant with respect to the rotational speed for each variable frequency.