JPS6054616B2 - Method and apparatus for simulating the rotating mass of a brake test stand - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for simulating a rotating mass on a brake test stand and the implementation of this method, in which the necessary energy is supplied by an electric machine and the brake torque is measured and integrated. It relates to a device for.

A method of this type and a device of this type are known from DE 27 58 117 A1.

In that case, the electric machine is adjusted to the desired speed of rotation, but
There is no disclosure regarding the simulated moment of inertia of the test stand. It is an object of the invention to provide a method and a device for simulating rotating masses, such that the test stand can be adjusted to the desired moment of inertia. According to the invention, such an object is achieved in the method mentioned at the outset by dividing the integrated brake torque by the difference between the output speed and the current instantaneous speed and calculating the quotient. This is achieved by supplying the moment of inertia to the control circuit as the actual value.

Furthermore, it is expedient to adjust the output rotational speed to a settable value. To carry out the method according to the invention,
In an arrangement in which the brake torque is detected by a force measuring device and amplified by an amplifier, the amplified measurement signal is fed to an integrator and the output of this integrator is applied to a first input terminal of the divider. A speedometer generator input and connected to the electrical machine is connected directly and via a sample-and-hold circuit operable at the start of a measurement to a subtracter, the output of which is It is particularly suitable if the second input of the divider is controlled and the output signal of this divider is fed as an actual value to a moment of inertia control circuit which influences the supply current of the electrical machine. Furthermore, in that case, the amplified measurement signal is zero co. It is expedient to provide that the control circuit for the moment of inertia can be disconnected via a switch and the control circuit for the output speed can be connected by means of the output of this zero comparator. There is. In this way, it is ensured that the electric machine is set to the desired rotational speed at the beginning of the measurement.

Next, the present invention will be described in detail based on embodiments shown in the drawings. The figure schematically shows an embodiment of the invention.
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A rotary brake disc 1 or a brake drum is connected to an electric machine 6, for example a direct current machine. Rotary mass 4 is a symbolic representation of the basic rotary mass of the test stand, and 5 designates an additional rotary mass that can be electrically connected. Of course, a number of additional rotating masses can be connected to the DC machine 6 as well. A fixed brake part 2, that is, a brake saddle for a disc brake, is swingably supported,
An electrical detector 3 is coupled to, for example, a load cell or a torque tube. The brake torque is then converted into an electrical signal, which is amplified by an amplifier 3a. The output of this amplifier 3a is input to an integrator 18, and the output signal of this integrator 18 is input to a divider 20. The other input of this divider 20 is controlled by a subtracter 30. The negative input terminal of the subtracter 30 is connected to the speedometer generator 7 connected to the DC machine 6, while its positive input terminal is connected to the sample and hold circuit 19. - This sample and hold circuit 19 is similarly connected to the speedometer generator 7 in a separable manner. The output signal of the divider 20 is sent to the subtracter 3
1 to the moment of inertia control circuit. The target value of the moment of inertia is set by the bodensiometer 22 and is supplied to the positive input terminal of the subtracter "31.
The output of 1 is connected to the moment of inertia regulator 21. The output signal of the regulator 21 is further supplied to a current control circuit 9, which controls an anti-parallel connected power converter 8 as an operating section. This power converter can draw or remove circuit current. The output of the power converter 8 is connected to the input of the DC machine 6. The output of amplifier 3a is connected to a zero comparator 17, which controls switches 16, 16a which short-circuit integrator 18 and divider 20 as long as no measurement signal is present.

Furthermore, the zero comparator 17 is connected to the contacts 12, 13 of the moment of inertia control circuit as long as the value of the brake torque is zero and instead a known speed control circuit is connected to the speed regulator 10. , 14 are opened.
Additionally, when the brake torque deviates from zero, the zero comparator opens the switch 15 which isolates the sample and hold circuit 19 from the speedometer generator 7. The known output speed control circuit uses a potentiometer 1 as a setpoint value generator.
It is composed of 1.

This potentiometer is connected to the positive input of the subtractor 32, its negative input is energized by the speedometer generator 7, and its output is connected to the speed regulator 10. The output of the rotation speed regulator 10 is on the one hand supplied to a current control circuit 9;
On the other hand, the regulator 2 merely causes the output voltage of the moment of inertia regulator 21 to follow the output voltage of the rotational speed regulator 10.
3. In addition, the speedometer generator 7 is connected to a zero comparator 33. This zero comparator 33 switches the switch 2 when the rotational speed of the DC machine 6 reaches zero.
4, thereby cutting off the current supply path of the DC machine 6. The device described above operates as follows.

As long as the brake saddle 2 is not activated, that is, as long as no brake torque moment is present, the DC machine is adjusted to the desired rotational speed via the above-mentioned control circuit for the output speed of the DC machine 6. Now, when the brake saddle 2 is actuated via a pneumatic or hydraulic device capable of regulating the brake pressure, the switch 14 is
15, 16, 16a are opened, switch 13 is closed, and switch 12 is switched. Therefore, a moment of inertia control circuit is connected from now on. The output signal of divider 20 represents the actual value of the total moment of inertia. Now, assuming that the current moment of inertia is smaller than the moment of inertia set in the potentiometer 22, the regulator 21 accelerates the DC machine 6 step by step until the two coincide exactly.
The DC machine then operates as a motor. On the contrary,
If the current moment of inertia is larger than the set moment of inertia, the DC machine
The control (brake) operates as a generator until it no longer registers the deviation of the actual value from the power standard value.
Provide auxiliary assistance to the process. In this way, very good control dynamics are obtained. DC machine 6 during the braking process
When the rotational value reaches zero, the switch 24 is opened, the DC machine 6 is de-energized and the test program is terminated, as described above. If during a scheduled test program of the brake torque this brake torque is brought back to zero again, the zero comparator 17 causes the switch 14 to
, 15, 16, 16a are closed, switch 13 is opened, and switch 12 is again switched to the rotation speed control circuit side. The DC motor 6 is therefore automatically readjusted to the output speed set on the potentiometer 11 when the braking process is interrupted.

[Brief explanation of the drawing]

The figure is a block diagram showing one embodiment of the present invention. 6... Electric machine, 7... Speedometer generator, 12, 13, 14, 15, 16, 16a... Switch, 17... Zero comparator, 18 ...
... Integrator, 19 ... Sample hold circuit, 20 ... Divider, 30 ... Subtractor.

Claims (1)

Claims: 1. A method for simulating a rotating mass of a brake test stand, in which the necessary energy is supplied from an electric machine and the brake torque is measured and integrated, in which the integrated brake torque is To simulate the rotating mass of a brake test stand, which is characterized in that it is divided by the difference obtained by subtracting the current instantaneous rotational speed from the output rotational speed, and the quotient is supplied as an actual value to the moment of inertia control circuit. method for. 2. The method according to claim 1, characterized in that the output rotation speed is adjusted to a settable value.
A method for simulating rotating masses on brake test stands. 3. The required energy is supplied by the electric machine, the brake torque is measured and integrated, the integrated brake torque is divided by the difference between the output speed and the current instantaneous speed, and the quotient is Device for implementing a method for simulating a rotating mass of a brake test stand, which is supplied as an actual value to a control circuit for the moment of inertia, the brake torque being detected by a force measuring device, and In such a device amplified by an amplifier, the amplified measurement signal is fed to an integrator 18,
The output of this integrator is input to a first input terminal of a divider 20, and a speedometer generator 7 connected to said electric machine 6 is directly connected to a sample and hold circuit which can be activated at the beginning of a measurement. 19 to a subtracter 30, the output of which controls the second input of said divider 20;
for simulating the rotating mass of a brake test stand, characterized in that the output signal of this divider 20 is supplied as an actual value to a control circuit for the moment of inertia which influences the supply current of the electric machine 6. Device. 4. In the device according to claim 3, the amplified measurement signal is supplied to a zero comparator 17, and the output of this zero comparator causes the switches 12, 1 to
3, 14, 15, 16, 16a to simulate the rotating mass of a brake test stand characterized in that the moment of inertia control circuit can be disconnected and the output rotation speed control circuit can be connected. equipment for.