JPS6048684B2 - gyroscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gyroscope device, particularly a so-called ``dynamically tuned free rotor''.
The present invention relates to a gyroscope device including a gyro.

A dynamically tuned free rotor comprising four inertial elements mounted on a drive shaft by means of spring couplings, which elements are rotated by the drive shaft and are free to rotate about another axis. It's becoming like that. Such gyros are designed such that the spin frequency of the drive shaft is equal to the natural frequency of the inertial element as it rotates on the spring support. Therefore, under these conditions, the inertial element is very sensitive to angular displacements of the drive shaft. The displacement of the inertial element relative to the drive shaft is measured with respect to two orthogonal axes lying in the plane of rotation of the inertial element, so a free rotor can be used instead of two single-axis gyros. The inertial platform has three mutually orthogonal axes to stabilize. Therefore, it is possible to use a single free rotor gyro with a conventional single axis gyro, or to use two free rotor gyros. Inertial platforms are commonly attached to aircraft and the time required to adjust the platform before the aircraft can take off is critical.

The platform must undergo a series of maneuvers that take several minutes before the aircraft can take off. Part of this time is spent waiting for the gyro to speed up. It is also common practice to change the gain of the leveling servo loop J in steps, which also takes time. It is an object of the present invention to provide a three-axis inertial platform having at least one dynamically tuned free rotor gyro and which can be adjusted more quickly, and a method for performing such alignment.

The invention provides a platform carried in a three-axis gimbal system, a shaft encoder and a torque motor connected to each axis of the gimbal system, at least one dynamically tuned motor carried on the platform and having two sensitive axes. a free rotor gyro carried on each sensitive axis of the gyro, two accelerometers carried on a platform and having sensitive axes aligned with the two sensitive axes of the gyro, two accelerometers carried on each sensitive axis of the gyro; a resolver device that applies a resolution signal to the appropriate gimbal torque motor in response to the output of the gyroscopic off on the sensitive axis, and the output of each gyroscope off as the gyromotor is accelerating to its normal operating speed; and a signal combining device operative to combine the output of an accelerometer on another gyro sensitive axis. The invention also provides a method for adjusting the gyroscope device, which includes the following process steps. (a) connecting the output of the shaft encoder on each gimbal axis to the torque motor on that axis before the speed of the gyro motor reaches its normal operating speed; (b) connecting the output of the shaft encoder on each gimbal axis to the torque motor on that axis; At each sensitive axis, the gyroscopic spin motor is accelerating to its normal operating speed by combining the output of the gyroscopic off with the output of the accelerometer on the other axis and decomposing the two combined outputs on the two Z axes. (c) applying the decomposition components to the gimbaled torque motors on the two axes; (c) adding the output of the gyrobic off on each J-axis to the torque on the coax when the gyro spin motor is running at its normal operating speed; 1 and 2 of the accompanying drawings.

The drawings show in block diagram form the various parts of an inertial platform using two free rotor gyros.
Double lines indicate mechanical connections between, for example, gimbal axes, shaft encoders, and torque motors. One of two free rotor gyros, Gyro 1- has two orthogonal axes GIX
) GIY, each axis is equipped with a gyrobic off and torque device.

These axes preferably coincide with the X and Y axes of the platform, each axis being equipped with an accelerometer. The second free rotor gyro, gyro 2', also has two orthogonal axes. One of these, axis G2Z, coincides with the Ξ axis of the platform and also includes a big-off and torque device.
The other axis of the gyro 2, axis G2R, is redundant and its big-off and torque device are connected in a closed loop to prevent its zero point from wandering. The three gimbal axes of the platform, namely GMI, GM2,
Each GM3 is equipped with a shaft encoder and a torque motor.

For convenience, gimbal axes GMI, GM2, and GM3 are considered azimuth, roll, and pitch, respectively. As shown in the figure, the gimbal movement ρM1, that is, the azimuth axis is the axis G2Z of the gyro 2.
is consistent with

On this axis there is a shaft encoder 10 and a gimbal torque
There is Umo Ichita 11. The output of shaft encoder 10 is applied to torque motor 11 via adder 12, switch SA and amplifier 13. The other input to adder 12 is an external reference signal. The shaft encoder 14 of the gimbal shaft GM2 is connected to a torque motor 16 via a switch SB and an amplifier 15, and the shaft encoder 17 of the gimbal shaft GM3 is connected to a torque motor 19 via a switch SC and an amplifier 18. As described above, the other axis G2R of the gyro 2 has its big-off 20 and torque device 21 connected in a closed loop via the amplifier 22. This loop is not necessary if a single axis gyro is used for gyro 2. The two gyro axes GIX, GIY are associated with gyro 1, which for the purposes of this invention must be a dynamically tuned free rotor gyro.

Gyrobic off 23 on axis GIX sends the signal to adder 2
Add to 4's solo power. The output of this adder is the resolver 25
added to. Similarly, gyrobic off 26 on axis GIY applies a signal to adder 27 whose output is also connected to resolver 25 . platform axis x
An accelerometer 28 is mounted on top. This accelerometer is actually arranged to respond to the acceleration of the platform along its Y axis, but senses gravity when tilted about the X axis. The output of the accelerometer is connected to a leveling filter 29 and a navigation computer 30. The output of the leveling filter 29 is connected via a switch SD to a gyrotorque device 31 on the X-axis and also to a second input of an adder 27 via a switch SE. Similarly, the platform axis Y
carries an accelerometer 32 that is arranged to respond to platform acceleration along the X-axis of the platform and to sense gravity when tilted about the Y-axis.

The output of this accelerometer is connected to a leveling filter 33 and a navigation computer 30. The output of the leveling filter 33 is connected via a switch SF to a gyrotorque device 34 on the Y-axis, and also to a second input of a summer 24 via a switch SG. The output of navigation computer 30 can also be applied to gyrotorque devices 31, 34 via switches SD, SF.

The resolver 25 decomposes the input into components around the orthogonal gimbal axes GM2 and GM3, and converts the appropriate components into swings SB and B.
C to the gimbal torque motors 16 and 19, respectively.

Switch SA can be actuated to directly connect the gyroscopic off 35 on axis G2Z to the gimbal torque motor 11 on gimbal mount ρM1, and the gyrotorque device 36 on that axis is connected directly to the navigation computer 30. Ru.

Each of the seven switches SA to SG is a four-position switch, and in the case of two switches SE and SG, the position is 3,
There is no connection to 4.

Each switch is actuated according to a series of steps in the platform adjustment operation, the number of steps being illustrated next to the switch contact. Next, the platform adjustment operation will be explained in detail.

Assume that the gyro is switched off and the platform is stationary, with all axes unadjusted. Adjustment operations are carried out in three stages according to the normal ``navigation'' mode under the control of the navigation computer. The first stage requires all switches SA-SG to be in position 1.

In this position, the shaft encoders on axes GM2, GM3 are directly connected to the corresponding gimbal torque motors. A shaft encoder 10 on axis GMI is connected to a coaxial torque motor 11 under the control of an external reference signal via an adder 12. The three shaft encoders provide outputs that indicate misalignment between the gimbal axis and its vehicle axis, so the effect of this step is to reduce the torque until the gimbal axis is at least approximately aligned with the vehicle axis. Drives the motor. It is to be.

This is a very fast operation, taking only 1 to 2 seconds, and can be employed even on conventional gyro-based platforms. At this stage, the output from the gyrobic off is not connected to the torque motor and therefore has no effect. Also during this phase the gyro spin motor is switched on and can begin running up to normal speed.

The next step in the adjustment operation is to move the switch 4 positions to position 2.

This only connects switches SB and SC. Therefore, only gyro 1 is stabilized, and gyro 2 is under the control of an external reference signal. Since there is a misalignment between the carrier axis and the vertical axis, the two accelerometers indicate the tilt of the stationary platform about the pitch and roll axes. As previously mentioned, the accelerometer 28 on the x-axis of the platform senses the tilt about this axis and the actual acceleration along the y-axis. The output of this accelerometer is applied to adder 27 via leveling filter 29 and switch SE. The output is then added to the output of the gyroscopic off 26 on the Y axis of the platform to indicate the actual offset of the gyro axis. The sum signal is applied to resolver 25. The output of the resolver is applied to the gimbal torque motors 16, 19 in a conventional servo manner to maintain a small output from the adder 27. Thus, the gyro axis is offset by an amount that depends on the accelerometer input to the adder. Unless the gyro has reached its normal operating speed, the suspension will not be synchronized to the operating speed.
For this purpose, a spring coupling exists within the gyro. Thus, the gyro offset acts on this spring coupling, which causes the gyro rotor to have an axis G.
This causes a preset around lX, thereby reducing the tilt sensed by accelerometer 28. Similarly, the tilt of the platform about the Y axis is sensed by an accelerometer 32, the output of which is sent to the gyrobic off 2 by an adder 24.
It is added to the output of 3. The summation signal is resolved by resolver 25 and applied to gimbal torque motors 16, 19 to deflect the X axis, thereby producing a preset about axis GIY to reduce tilt. The force of the spring coupling within the gyro decreases as the gyro spin motor approaches its normal speed, so the motor acceleration rate is set to allow time for this stage to complete. . During operation, the accelerometer outputs are also applied to the gyrotorque device through leveling filters, but these signals are very small compared to the presets produced by the spring couplings. During the first two stages, the gyro 2 is adjusted around the axis G2Z by an external reference signal.

Stage 3 of the adjustment operation occurs when the gyro spin motor is running at its normal speed and each switch is moved to position 3.

In this case there is no spring coupling between the gyro axes and the technique of stage 2 is no longer available. In this case, all three axes are directly controlled by the gyroscopic off switch. The tilt error is very small as a result of the first two steps, so the accelerometer output is small or non-existent. In each axis a gyrobic off signal is applied to the appropriate gimbaled torque motor. In this case the leveling loops are under the control of gyrotorque devices, these torque devices being arranged with fairly long time constants, so that movements of the platform carrier do not influence the platform adjustment. Such movements result from starting aircraft engines, moving people, etc. In this case, the output of the leveling filter is processed by the navigation computer, for example to provide a more precise adjustment of the gyrocompass. The adjustment operation is completed through the three steps described above.

In normal use, the switch is moved to position 4;
The gyrotorque devices on the three axes are therefore controlled by the navigation computer 30. The computer receives input from the accelerometer and the leveling filter is usually ignored in this mode. The main time savings in the operation described above is due to the fact that the second stage relies on a spring coupling that is present when the dynamically tuned free rotor gyro is operating below its design speed.

Therefore, the acceleration time of the motor is initially utilized to provide a fast leveling response, which is then automatically extended to the slow response necessary to minimize the effects of carrier motion. Vertical adjustment is substantially completed within the gyro run-up time. In conventional schemes using only gyrotorque motors, run-up time is usually wasted time due to high drift rates, which in dynamically tuned free rotor gyros are limited to operating at their design speed. It can happen when you don't. The reason for this is that gyrobic off does not necessarily give a true indication of the undeflected position of the gyro suspension. The deflection and spring rate produced act to bias the leveling group in a direction that displaces it from the position that the accelerometer indicates to be the true vertical position. Because the spring rate changes over time as the gyro motor accelerates, conventional techniques have difficulty taking this effect into account. In contrast, in the present invention, a fixed error proportional to the big-off error is introduced through the adjustment operation, which is small and can be easily taken into account. Another advantage is that much higher preset rates are achieved using the method of the present invention than when using conventional gyrotorque devices. This allows faster removal of larger initial misalignments, which means that the first stage of the operation can be performed faster. The operations described above are also applicable when the platform has only one dynamically tuned free rotor gyro, since the Ξ-axis stabilization is usually obtained from an external source.

[Brief explanation of the drawing]

Figures 1 and 2 are block diagrams showing the various components of an inertial platform using two free rotor gyros. GIX, GIY, G2Z, G2R... Gyro axis, GMI, GM2, GM3... Gimbal axis,
SA~SG...Switch, 10, 14, 17.
...Shaft encoder, 11, 16, 19.
...Torque motor, 13, 15, 18...
・Amplifier, 23, 26... Big off, 12,
24, 27... Adder, 25... Resolver, 28, 32... Accelerometer, 29, 33...
... Rebeling filter, 30 ... Navigation 5 computer, 31, 34, 36 ... Gyrotorque device.

Claims (1)

[Claims] 1. A platform carried on a three-axis gimbal system; a shaft encoder and a torque motor connected to each axis of the gimbal system; carried on the platform and having a gyroscope spin motor and two sensitive axes; at least one dynamically tuned free rotor gyroscope; a pick-off and torque device connected to each sensitive axis of the gyroscope; a receiver carried on the platform and aligned with the two sensitive axis of the gyroscope; two accelerometers with sensitive axes; a resolver device that responds to the output of the gyroscope pickoff on each sensitive axis of the gyroscope and applies a resolved signal to the appropriate gimbaled torque motor; a gyroscope spin motor at its normal operating speed; Only when you are driving at a speed of
a signal coupling device operative to couple the output of each gyroscope pickoff with the output of an accelerometer on another sensitive axis of the gyroscope such that a spring coupling exists between the sensitive axes of the gyroscope; including gyroscope equipment. 2. a signal combining device, in each sensitive axis of the gyroscope, an adder operative to combine said two output signals, and a filter device for ensuring that the output of the accelerator is applied to the appropriate adder; a switch device operative to connect the output of the filter device to a suitable summer only when the gyroscope spin motor is operating at its normal operating speed. Device. 3. The gyroscope apparatus of claim 2, wherein the switch device is operative to connect the output of each gimbal axis shaft encoder to the gimbal torque motor on that axis before the speed of the gyroscope spin motor increases. . 4. A platform supported on a 3-axis gimbal system; a shaft encoder and a torque motor connected to each axis of the gimbal system; at least one supported on the platform and having a gyroscope spin motor and two sensitive axes; a dynamically tuned free rotor gyroscope; a pickoff and torque device connected to each sensitive axis of the gyroscope; 5 sensitive axes carried on a platform and aligned with the two sensitive axes of the gyroscope; two accelerometers having: a resolver device that applies a resolved signal to the appropriate gimbaled torque motor in response to the output of the gyroscope pickoff on each sensitive axis of the gyroscope; a speed at which the gyroscope spin motor is below its normal operating speed; There is a spring coupling between the sensitive axes of the gyroscope, coupling the output of each gyroscope pickoff with the output of the accelerometer on the other sensitive axis of the gyroscope only when driving at (a) before the speed of the gyroscope spin motor reaches its normal operating speed, the output of a shaft encoder on each gimbal axis is adjusted to Connecting to the gimbal torque motor on; (
b) Combine the output of the gyroscope pickoff in each of the two sensitive axes of the gyroscope with the output of the accelerometer on the other axis, decompose the two combined outputs for the two axes, and generate the gyroscope spin motor. (c) applying the resolved components to the gimbaled torque motors on the two axes only when the gyroscope spin motor is running at a speed less than its normal operating speed; (c) when the gyroscope spin motor is running at its normal operating speed; Connecting the output of the gyroscope pickoff on each axis to a gimbal torque motor on the same axis and applying a control signal to the gyroscope torque device; A method for adjusting a gyroscope device comprising the above sequential steps.