SU1495666A1 - Bench for dynamic testing of vehicles - Google Patents

Abstract

The invention is intended for running in and various tests and is an all-wheel drive system of cross-country drums with loads, in which each wheel of the vehicle rests on a pair of cross-drums. The purpose of the invention is to increase efficiency by increasing the range of test vehicles and expanding the functionality of the stand by expanding the range of test modes. An electric machine 5 and 6, respectively, are connected to each drum 1 and 2 of the stand, the core windings of each pair of machines connected by means of the drums 1 and 2 to one wheel 3 are interconnected in series and connected to regulator 7. To other regulators 10 and 11, the excitation windings 8 and 9 are connected, and the regulation system 13 comprises sensors and current adjusters of the cores, the sum of the difference of the excitation currents of each pair of machines. 2 Il.

Description

4: CO C71

O5 O 05

3149

The invention relates to a transport technique, in particular to test, rolling and brake stands for the diagnosis of wheeled vehicles in which the active wheels of the vehicle rest on a pair of rollers each.

The aim of the invention is to improve efficiency by increasing the range of test vehicles and expanding the functionality of the test bench by expanding the range of test modes.

Figure 1 shows the electromechanical power circuit of a test drum stand; Fig. 2 is a diagram of the automatic control of the stand loading devices.

The test bench (Fig. 1) is a system of support running drums 1 and 2, the number of pairs of which is equal to the number of active wheels 3 of the test machine 4. Each of drum 1 and 2 is connected to the electric machine 5 and 6, respectively, the main windings - which are connected in pairs in series and connected to voltage regulators 7, and their windings 8 and 9 of independent excitation are connected to regulators 10 and 11 of the excitation current, respectively. Regulators 7, 10 and 11 are connected to supply voltage 12 by means of switches (not shown) and are connected to automatic control system 13. The latter is also connected to the supply network 12 and to the stand control system 14.

A part of the automatic control system 13 relates to a pair of support drums 1 and 2, designed to regulate the load on the active wheel 3 of the vehicle 4 (Fig; 2) and contains the voltage control unit 15 of the voltage regulator 7, the current control blocks 16 and 17 excitation of the regulators 10 and 11 of the excitation current and electric machines-5 and 6, the sensor 18 and the setpoint 19 of the current of the main pair of machines 5 and 6 are connected to the voltage regulator 7 by means of the comparison unit 20 and the control unit 15 wives, sensor 21 and master 22 total excitation associated with the regulators 16 and 17 of the excitation currents by means of a comparison unit 23 and blocks 16 and

17 adjustment of field currents,. the sensor 24 and the setting device 25 of the excitation current difference connected to the controller 16 by means of the comparison unit 26. Sensor 18 is installed in the circuits of machines 5 and 6. Sensors 21 and 24 are functional computing units, including the actual current sensors installed in the circuits of the excitation windings 8 and 9, and summation units. Setters 19, 22, and 25 are associated with stand control system 14. In addition, the system

13, the automatic adjustment comprises channels for adjusting the frequency of rotation of the wheels 3 and the angles of rotation (not shown).

The stand works as follows.

The vehicle 4 enters the stand, each of its active wheel 3 being mounted on a pair of reels 1 and 2. Regulators 7, 10 and 11 and the automatic control system 13 are connected to the supply voltage network 12.

Then the test machine 4 begins to accelerate with its engine, the drums 1 and 2 are driven to rotate with their active wheels. When idling, the control system 14 does not cause the signal to turn on regulators 7, 10 and 11 and the electric machines 5 and 6 rotate without active load, creating on the shafts of the drums 1 and 2 only the inertial load.

When running under load system

14 control gives a signal to activate the regulators 7, 10., and 1 1. On the windings of machines 5 and 6, the currents of the core and excitation begin to flow, and braking torques appear on the shafts of machines 5 and 6 and drums 1 and 2, creating loads for the wheels 3 of the test vehicle 4. At the command of the control system 14, which sets the same settings control for all machines 5 and 6, the automatic control system 13 maintains the same amount of braking torque on the shafts of all the drums.

When running in reverse, the order and nature of the work of the stand does not change.

Braking tests are conducted in a similar order, but before braking is initiated by a signal from control system 14, machine 5 and 6 are reversed, for which purpose to one of the windings 8

and 9 — root or excitation — the polarity of the connection of the corresponding current regulator 7 or 10 and 11 changes.

Depending on the test conditions, either the equal torque of the machines 5 and 6 on all the shafts of the drums I and 2 can be ensured, or their predetermined different values for each of the active wheels 3 of the machine 4. In this case, the control system 14 sets different settings . current for each regulator 7 and the sum of the excitation currents for each pair of regulators 10 and 11, and the system

13 adjustments maintains an appropriate amount of current and excitation currents of each pair of machines.

5. and 6.

When imitating on the stand mode of vehicle turning systems

14, the control sets different current settings for electric machines that, by means of drums, are coupled to the wheels of different sides of the vehicle. In order to control such modes, the control system 14 adjusts the signals of the setting units 19 and 22 in accordance with the signals of the wheel speed sensors and the steering angles.

Testing at the stand of transport; equipment of different weights and with different weight distribution over the axles; required to change the total test load on the wheels of the vehicle and to change the distribution of the total load between the drums. This task is solved by setting a different overall signal level of the setting units 19, and a different level of signals of the various setting units 19 by the stand control system 14.

It is known that, when the stand loadlers operate, at the points of contact of each wheel 3 with the corresponding drums 1 and 2, tangential forces arise, the occurrence of which leads to a redistribution and normal reactions at these points. As a result of this, the ratios of normal and tangential forces at the points of contact change and, accordingly, the conditions of coupling between the forest and the rinks. When braking, the normal response at the point of contact of the wheel 3 with the front in the direction of installation of the machine 4 at the stand drum 1 decreases, and at the contact point

d 5

0

five

the one with drum 2 is increased. With very high braking forces, the normal response from the first roller to zero gives and the machine is thrown back from the rollers. Under less conditions, the normal response is reduced to a tangent value and the roller starts to slip relative to wheel 3.

The conditions of adhesion at two points of contact of wheel 3 with drums 1 and 2 at high forces can be equalized by redistributing tangential forces between the rollers - reducing the tangential force on the first and increasing on the second rink when braking and vice versa during acceleration. For this, the control system 14 sets the torque error signal of the machines 5 and 6 as an error signal of the drive currents in the windings 8 and 9 of these machines. The control system 13 maintains the difference specified by this signal in the braking process, regardless of the absolute magnitude of the torques. In this case, the total load on the wheels remains unchanged.

In the process of adjusting, the signals of the setpoint adjusters 19, 22 and 25, the total excitation current and the difference of the excitation currents arrive at the inputs of the comparison bds, 20 and 23, the other inputs of which receive signals from the respective sensors 18, 21 and 24. The error signals from the block output 20, 23 and 26 comparisons are fed to the inputs of the control units 15-17. In block 16, they are warehouses- Q vajuts c j then in all blocks the amplification

0

five

It is converted into control signals at the inputs of the regulators 7, 10 and 11, causing a corresponding change in the controlled parameters.

rametrov.

Depending on the sign of the reference signal of the block 25, the excitation current of the machine 5 varies in one direction or another. Machine excitation current

6 varies in the opposite direction due to the signal of the feedback unit 21 for the total excitation current. As a result, the load moment (traction or brake) of each pair of electric machines 5 and 6

m sfr 1 „,

where C is electromagnetic. machines 5 and 6;

f is the magnetic flux of the corresponding machine;

IPJ is the current of the core, and the difference in the torques of the machines of each pair

4M - (| SFA-SFB |). Ie the total moment of a pair of machines does not depend on their difference.

Due to the possibility provided in the stand scheme, both coordinated and independent control of pairs of load electric machines associated with each wheel transport: Nogo means separately, the stand has full versatility. It allows the vehicle to be tested when the latter is working from its own engine and the engine when working from stand electric machines. It allows to imitate any modes of acceleration, braking, turning, reversing, - reverse running under any possible loads in road conditions and with loads that significantly exceed their magnitude. The latter is achieved by creating optimal conditions for coupling each wheel to the stand drums due to the mutual adjustment of the load moments of each pair of electric machines associated with one vehicle KOjiecoM each, with the total load moment on the wheel constant. This allows us to significantly move the limit of possible loads on the stand to a region of very large values that did not resort to the structural complexity of the stand. This effect is achieved solely by the automation of the stand and, therefore, operation and testing on the stand is simplified.

Claims (1)

Invention Formula The stand for dynamic testing of vehicles, containing a frame supported on its base and reinforced on it with drums pair for each active wheel of the vehicle, load devices made in the form of electric machines, voltage regulators and excitation current of machines, an automatic control system machines and stand control system, characterized in that, in order to increase efficiency by increasing the range of tested vehicles and expanding functional capabilities of the stand by expanding the range of test modes, with each drum an electric machine kinematically connected, the main windings of every two machines connected by means of the drums to one wheel of the vehicle are connected in pairs in series to each other and connected to the voltage regulator, the excitation windings of all electric machines are connected to individual field current controllers, and the automatic control system includes sensors and current setors of the core of each pair of electrical machines connected to the voltage regulators of the respective pair of machines, sensors and setting devices of the total excitation current of each pair of electrically machines connected with the regulators of the excitation current of the respective machines, and sensors and setting devices of the difference of the excitation currents of each pair of electric machines associated with one of the regulators of the excitation current of each pair of machines. FIG. 2