Kinematic observers for active control of helicopter rotor vibration

A simple scheme for estimating the state variables of a helicopter rotor is presented. The method incorporates the use of blade-mounted accelerometers and/or position transducers to reconstruct modal displacements and velocities. The design of the observer structure and feedback gains is simplified by the fact that the method requires only knowledge of basic kinematic relationships between the various modal quantities. The observer structure described is particularly well-suited to control problems where the use of a traditional Kalman Filter approach would be too complex or costly. The technique can be viewed as decreasing the requirements on observer complexity while increasing the need for an enhanced sensor complement.