An observer to improve the speed signal using a Ferraris acceleration sensor
Jochen Faßnacht, P. Mutschler · 2001
Servo drive systems for high dynamic applications need precise measuring signals. The incremental encoder for position measurement is well known. In recent time there is also an acceleration sensor for rotational drives available. The combination of both sensors – a Ferraris sensor and an incremental encoder – promises great benefits [1]. In a speed controlled system the accurate speed signal is very important. If a state control is chosen to improve the performance of the system the accurate acceleration of the machine rotor is also interesting. These signals could also be generated by a state observer using the calculated machine torque and the measured position, but especially in an application with high disturbance torques the measured acceleration is preferable. The generation of the speed and acceleration signal by time discrete differentiation of the position signal amplifies the measuring noise inherently in control systems with small cycle times. In this paper the performance, advantages and disadvantages of the two sensor devices are discussed. Possible algorithms to correct the acceleration signal and a state observer to generate a better speed signal are presented.