(c) 2000, 2014 Akos Szoboszlay
The rate table (cylindrical object in foreground with motor coils) is used for testing. It moves back and forth as commanded by the generator inside the Dynamic Signal Analyzer (instrument at left), using either a swept sine or a random noise pattern (for faster testing). Mounted on the rate table is a gyro (short cylindrical object) and an Inertial Angle Sensor (long cylindrical object). Behind the black circular dust cover is a mirror that is used to for some tests. The Dynamic Signal Analyzer (instrument at left) is now set up for frequency response testing. It is also is also used for noise testing.
Akos Szoboszlay designed the following:
The rate table electronics and servo loop with optical linear position feedback.
The gyro which I co-designed the capture loop, and
The gimbal (huge ring partly seen in picture) which used my servo design with a quad sensor giving angular position feedback. What was tested was the rate (same as angular velocity) from the gyro and Inertial Angle Sensor (after these were packaged in one unit).
Akos Szoboszlay used the rate table and the Dynamic Signal Analyzer (HP 3562A) to blend the gyro -- which had excellent low frequency response but not meeting bandwidth requirements by itself -- and the Inertial Angle Sensor's capture loop -- containing no DC information but having excellent high frequency response, to 300 Hz. The Inertial Angle Sensor was put into a capture loop which converted the signal from angular position to angular acceleration. An LPF (Low Pass Filter) converted that to angular velocity above the corner frequency, f0. The same LPF was used on the gyro signal, to obtain -20 dB/decade above the f0. The two signals were blended together by summing after matching the gains of the two signals. This blend was then further flattened by a "shaping filter" within 0.25 dB flatness (up to 18 Hz). I used the Dynamic Signal Analyzer to obtain the poles and zeros of the response, and then designed the inverse response with op amps, capacitors and resistors, which was the shaping filter. I also used the Dynamic Signal Analyzer to compensate and test the capture loops. I also used it to obtain noise plots, and used this information to reduce noise.
Shown is Akos Szoboszlay looking at plot results. The two power supplies (at right) power the rate table.