The AAA200 Series of Servo Accelerometers measure vector acceleration with high accuracy using a closed loop force balance torquer mechanism.
All AAA200 Series Accelerometers operate as a closed-loop torque balance servo system. With reference to the illustration below the pendulous mass ‘A’ develops a torque proportional to the product of its mass unbalance and the applied acceleration. The movement of mass ‘A’ is detected by position sensor ‘B’ whose output signal is connected to an amplifier. The resulting current is fed into the torquer motor ‘C’ which then develops a torque exactly equal to, but directly opposed to the initial torque from the pendulous mass ‘A’. Mass ‘A’ stops moving, assuming a position minutely differing from it’s zero ‘g’ position. Simultaneously, the current to the torquer motor is fed through a stable resistor to provide an output voltage proportional to the applied acceleration.
The system is electronically damped by means of a phase advancing network within the integrated servo amplifier. By adjusting the parameters of the servo amplifier and related electronic networks, the operating characteristics of a servo accelerometer can be optimised to suit a particular application.