SU934392A1 - Stand for graduating and testing accelerometers - Google Patents

Description

(5) STAND FOR GRANNING AND TESTS OF ACCELEROMETERS.

The invention relates to a measuring technique and can be used for the calibration of angular and linear accelerometers and their testing for the effects of accelerations varying in a sinusoidal manner. A known installation for calibrating accelerometers, comprising a rotating platform and a harmonic modulator, located on its fl. The closest in technical essence and the achieved effect to the invention is a stand consisting of a platform rotated by an electric drive on which a harmonic modulator is located containing a drive and two balanced masses fixed on a rotating rod, the axis of rotation of which is intersected with the axis of rotation. the platform, and the movement of the masses is combined with this axis 21. The work of the stand is based on the principle of periodically changing the moment of inertia of the moving system relative to the axis of rotation of the platform, which causes an effect on the accuracy of the calibration of a number of factors accounting nepoddayuschihs (dynamic imbalance moving masses, the variable load on the bearings, unstable frictional torque, backlash kinematics elements, etc.). In addition, the presence on the platform of a system of rotating masses with a drive and a conductor to it causes additional intrinsic noise. The purpose of the invention is to improve the accuracy of accelerometer calibration, simplify the design and expand the range of reproducible accelerations. The goal is achieved by the fact that in the stand for calibration and testing of accelerometers, containing a rotating platform with a drive and a device for harmonic modulation, this device is made in the form of two selsyns, the stator and rotor windings of which are respectively connected, and the rotor of one selsyn is rigidly fixed 39 its stator, and the rotor of another rigidly mounted on the shaft of the platform. In addition, the stators of the selsyn and the drive motor of the platform are connected to adjustable power sources. In FIG. 1 is a schematic of the device for calibrating accelerometers in FIG. 2 - graphs showing the work of the stand. The device comprises a shaft 1 with a platform 2 for mounting a test accelerometer 3 and an electric motor k mounted on an anchor 5- On the shaft 1, a rosin 6 rotor is rigidly fixed. The stator windings 7 and 8 of the selsyns are fed from the source 9 of an adjustable alternating voltage. An electric motor with a naturally soft mechanical characteristic is supplied with power from a controlled constant voltage source 10. The rotor 11 of the other selsyn is inhibited. The device works as follows. When the motor is on, the platform is informed about the rotation around its axis. The transmission of voltage from the power supply to the stator windings of the selsyn creates a synchronizing moment Sync Sykr vnw sinwt, (1) which will modulate the moment of static resistance of the engine sinusoidally. The engine in conjunction with the steady-state S platform is described by equations. , do; dt c + where Cj and Cg are the proportionality coefficients between the current of 5 cor and the rotating moment, as well as between the speed of rotation of the reverse EMF.

   ° resistance

root chain;

I. - the moment of inertia of the rotor of the engine and platform; and - supplied to the engine

voltage;

OU - platform rotation speed; 0

Claims (2)

1. Stand for calibration and testing of accelerometers, containing a rotating platform with a drive and a device for harmonic modulation, characterized in that, in order to improve the accuracy of the graduation method 2 MC, the torque of the static resistance of the engine. The acceleration of the platform in this case is 01 ksino t, (3) where k is the coefficient of proportionality. When calibrating linear accelerometers, they are placed on the platform so that the center of inertia of the inertial mass of the accelerometer is at the calculated distance from the axis of rotation of the platform, and, the axis of sensitivity was oriented in the direction of linear acceleration. When calibrating angular accelerometers, they are positioned on the platform so that the axis of rotation of the platform coincides with the axis of sensitivity of the accelerometer. In 1 quadrant (Fig. 2) of the BP line, the mechanical characteristic of a DC motor with independent excitation is natural. By using an adjustable DC power source, the slope of the characteristic n f (M) can be changed, i.e. change the rigidity of the mechanical characteristic, which leads to the expansion of the amplitude range of reproducible accelerations (bk) | dm). For the same purpose, a change in the supply voltage of the stator windings of the circuits {quadrant IV, fig. 2). This changes the value of the maximum synchronizing moment (b k) (d m). Installing accelerometers directly on the platform and eliminating loads modulating the moment of inertia of the moving system and their power drive current leads improves the accuracy of accelerometer calibrations and reduces the device's own noise. Replacing the modulator with two selsyns also improves the accuracy of calibration and simplifies the design of the stand. accelerometer kits, simplifying the design and expanding the range of reproducible accelerations, the harmonic modulation device is made in the form of two selsins, the stator and rotor windings of which are respectively connected, the rotor of one selsyn rigidly fixed with respect to its stator, and the rotor of the other rigidly fixed on the shaft of the platform. 2. Stand according to claim 1, of tl and h ayush and with TCMj that the stators of selsyns and the platform drive motor is connected to adjustable power sources. Sources of information taken into account in the examination 1. USSR author's certificate N398873, cl. G 01 p 21/00, 2k.M.7. 2. USSR author's certificate No. 593155, cl. G 01 P, 15-02.78 (prototype). fug. Fg / g g fF uf