JP2013148485A - Torque detection device of dynamometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a fluctuation portion from overlapping with detection torque by allowing vibrations to vibrate an acceleration sensor through an oscillator when a rotator rotates at a high speed when performing torque detection by a dynamometer.SOLUTION: A torque operation part 3 is provided with a filter part 31 for vibration elimination. A difference between a torque command value detected by the torque operation part 3 and a detection torque value detected by a load cell is inputted to the filter part 31. A difference between an output from the filter part and the torque command value is defined as an output signal of the dynamometer.

Description

  The present invention relates to a torque detector for a dynamometer, and more particularly to a torque detector that does not require an acceleration sensor.

  In the case of a dynamometer (dynamometer) having a peristaltic mechanism used for an engine dynamometer system or a chassis dynamometer, the load cell used for torque detection includes a dynamometer perforator in addition to the torque actually detected by the dynamometer. Torque fluctuations due to the natural vibrations are added and output. The torque fluctuation due to the natural vibration of the slider is not necessary for torque detection, and Patent Documents 1 and 2 are known as methods for removing the fluctuation.

  That is, in Patent Document 1 and Patent Document 2, an acceleration sensor is attached to a swing element to detect an acceleration signal, and the detection signal and the load cell detection signal are added to remove the natural vibration of the swing element.

JP 58-90135 A Japanese Utility Model 1-14836

The methods of Patent Documents 1 and 2 are sufficient as a countermeasure for eliminating fluctuations when used at a relatively low speed, such as a chassis dynamometer, but in an engine bench system used up to a high speed, a dynamometer rotor is used. It rotates at a high speed, and the vibration caused by the rotation causes the acceleration sensor to vibrate via the slider. Among these vibrations, the peristaltic direction is canceled with the output signal of the load cell, but since the vibration in the axial direction and horizontal waveform is included, the above-mentioned vibration enters the torque detection at high speed rotation in the conventional method,
Spoil detection with less fluctuation component due to swinging at high speed response with anti-folding measures. For this reason, conventionally, a method of removing a torque fluctuation associated with high-speed rotation by adding a filter according to the rotational frequency to be used is employed, and the number of additional parts is increased.

Accordingly, an object of the present invention is to provide a torque detector for a dynamometer that does not require an acceleration sensor or additional components.

The present invention controls a peristaltic dynamometer through an inverter based on a torque current command value, and detects torque using a load cell.
A torque calculation unit for inputting the torque current command value and calculating a torque command value of the dynamometer is provided, and a filter unit is provided in the torque calculation unit. The signal TLc ^ output from the filter unit and the torque command value Tdy The difference between the difference Tdy ^ and the detected torque value TLc detected by the load cell is input to the filter unit, and the difference between the signal output from the filter unit and the torque command value is used as the output signal of the dynamometer. It is characterized by comprising.

  The filter section used in the present invention is characterized by comprising a 1 / Tk · s integrator.

  Where Tk is a filter constant and s is a Laplace operator.

  As described above, according to the present invention, it is only necessary to use the torque current command value of the inverter that controls the dynamometer in addition to the torque detection by the load cell as the torque detection device. The natural vibration can be removed without mounting the torque, and the number of parts for torque detection can be reduced. Further, since no acceleration sensor is used, it is possible to detect torque without rotational vibration during high-speed rotation.

The block diagram of the torque detection apparatus which shows embodiment of this invention. Waveform diagram for explanation.

  FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, in which 1 is a torque command unit, 2 is a measurement unit including an inverter and a dynamometer body, and 3 is a torque calculation unit. The torque command unit 1 is a part of an inverter control circuit that controls the dynamometer, and uses a value based on a set value or a torque detection value fed back and stored in the inverter panel, and controls it. A torque current command Is is output from the torque current command generation unit 10 in the circuit. The torque current command Is is output to the measurement unit 2 and the torque calculation unit 3.

The measuring unit 2 detects torque by an inverter 20 for controlling torque of the dynamometer based on the torque current command Is, a dynamometer unit 21 controlled by the output of the inverter 20, and a load cell connected to the dynamometer slider. A load cell torque detector 22 and a torque amplifier 23 are provided.
The torque Td of the dynamometer 21, which is the shaft output of the dynamometer, is output as a detection signal TLc0 of the load cell detector 22 as a sum of disturbances Tdis such as natural vibrations of the slider, and is set to a predetermined value by the torque amplifier 23. Amplified to become a load cell detection signal TLc, which is input to the torque calculator 3.

  The torque calculation unit 3 includes a model unit 30 that models an inverter and a dynamometer, and a filter 31, and the input torque current command Is is converted into a shaft torque Tdy in the model unit 30. As the calculated shaft torque Tdy, a torque command value based on the torque current command Is is used in an inverter control circuit (not shown). Here, in order to facilitate understanding, the model unit 30 is used. I will explain it. That is, the torque generated by the dynamometer basically matches the torque current command Is for which the inverter performs vector control. Therefore, the model unit 30 is configured as a control model of Is / Tdy conversion, and is output to the subtracting unit 33 as a shaft torque Tdy proportional to the torque current command Is.

  An output TLc ^ that has passed through the filter unit 31 is input to the subtractor 33, and the subtractor 33 performs a difference operation between the shaft torque Tdy and the output TLc ^ to obtain an output signal Tdy ^ of the dynamometer. The output signal Tdy ^ of the dynamometer is subjected to a difference operation with the load cell detection signal TLc in the subtracting unit 34, and the deviation signal is input to the filter unit 31. Here, Tk in the filter unit 31 is a filter coefficient, and s is a Laplace operator.

Next, the operation of the present invention will be described.
In the steady state, the output Tdy of the model unit 30 is negatively added in the subtraction unit 33 in a loop that passes through the filter unit 31 for vibration removal, so that the load cell detection torque (output of 31) TLc ^ of the filter output and the model The dynamometer torque in operation and the dynamometer torque (output of 33) Tdy ^ as the calculation result of the filter output are obtained from the equations (1) to (3).
TLc ^ = (Tdy ^ -TLc) * (1 / Tk.s) (1)
Tdy ^ = Tdy-TLc ^ = Tdy- (Tdy ^ -TLc) * (1 / Tk.s) (2)
Expanding this, Tdy ^ = Tdy-Tdy ^ * (1 / Tk * s) + TLc * (1 / Tk * s) (3)
Also, (Move to the left side to compile this with Tdy ^)
Tdy ^ + Tdy ^ × (1 / Tk · s) = Tdy + TLc × (1 / Tk · s) (4)
(Summarize this with Tdy ^)
Tdy ^ {1+ (1 / Tk · s)} = Tdy + TLc × (1 / Tk · s) (5)
Are in a relationship. Therefore, the output signal Tdy ^ of the dynamometer is

Or (divide the numerator denominator by (1 / Tk · s))

Thus, the expressions (6-1) and (6-2) become the evaluation expressions.

That is, in (6-1), if (1 / Tk · s) ≈0, then Tdy ^ at t = 0,

And the output is Tdy ^ = Tdy.

  In the equation (6-2), when t = ∞, 1 / Tk · s = ∞,

So,

The output is Tdy ^ = TLc.

FIG. 2 is a waveform diagram showing the above relationship. The output of the torque command Tdy from the model unit 30 becomes 0 at the time t when the output Tdy ^ of the subtraction unit 33 gradually decreases as shown in FIG. TLc = 0).
On the other hand, the detected torque TLc by the measuring unit 2 is filtered by a loop passing through the filter 31 for vibration removal, and finally becomes the detected torque TLc≈output torque Tdy ^ as shown in FIG. (However, Tdy = 0). Therefore, the dynamometer output signal Tdy ^ which is the output of the subtractor 33 becomes the signal output signal Tdy ^ of the sum of (a) and (b) in the subtractor 33 as shown in FIG. The dynamometer output signal Tdy ^ from which the natural vibration torque of the child and the detection noise component of the load cell are removed is obtained.

Since the output Tdy of the model unit 30 in the transient state is not negatively added in the loop passing through the filter 31, the change ΔTdy ^ is the filtered detected torque TLc ^ (≈dynamometer torque Td) before the change. It is added and substantially coincides with the changed dynamometer torque Td. That is, Tdy = ΔTdy ^ + TLc≈Td
It becomes. Therefore, in the transient state, the dynamometer torque Td without detection delay due to filtering can be detected in the output signal Tdy ^ with a high-speed response.

As described above, according to the present invention, it is only necessary to use the torque command value of the inverter that controls the dynamometer in addition to the torque detection by the load cell as the torque detection device. The conventional parts such as an acceleration sensor need not be attached to the child.
In addition, the filter unit can remove torque fluctuations due to the natural vibration of the slider and noise components of torque detection by the load cell, and can ensure the torque detection accuracy by the load cell in a steady state.
Furthermore, even in an excessive state, high-speed torque detection by torque current control is possible, torque detection without fluctuation such as rotational vibration at high-speed rotation is possible, and high-response torque detection without detection delay by filtering is possible It will be.

DESCRIPTION OF SYMBOLS 1 ... Torque command part 2 ... Measuring part 3 ... Torque calculating part 10 ... Torque current command generation part 20 ... Inverter 21 ... Dynamometer part 22 ... Load cell 30 ... Model part 31 ... Filter part

Claims (2)

In a torque detection device that controls a peristaltic dynamometer via an inverter based on a torque current command value and detects torque using a load cell,
A torque calculation unit for inputting the torque current command value and calculating a torque command value of the dynamometer is provided, and a filter unit is provided in the torque calculation unit. The signal TLc ^ output from the filter unit and the torque command value The difference between the difference Tdy ^ and the detected torque value TLc detected by the load cell is input to the filter unit, and the difference between the signal output from the filter unit and the torque command value is used as the output signal of the dynamometer. A torque detector for a dynamometer characterized by comprising. The dynamometer torque detection device according to claim 1, wherein the filter unit includes a 1 / Tk · s integrator.
Where Tk is a filter constant and s is a Laplace operator.

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