Sensorless wave based control

Official URL: http://192.168.1.20/record=b1293855 (Table of Contents)

Mechanical waves naturally propagate through dynamical systems that are subjected to initial excitation. These mechanical waves carry enough information about the dynamical system including its dynamics and parameters, in addition to the externally applied forces or torques due to the system's interaction with the environment. In other words, mechanical waves carry all the dynamical system's information in a coupled fashion. This thesis proposes an estimation algorithm that enables estimating flexible systems' dynamics, parameters, externally applied forces and disturbances. The proposed algorithm is implemented on a lumped system with an actuator located at one of its boundaries, that is used as a single platform for measurements where actuator's current and velocity are measured and used to estimate the reflected mechanical waves. Only these two measurements from the actuator are required to accomplish the motion and vibration control, keeping the dynamical system free from any attached sensors by considering the reflected mechanical waves as a natural feedback from the system. In this thesis the notion of position estimation is proposed including both rigid and flexible motion estimation, where the position of each lumped mass is estimated and experimentally compared with the actual measurements. This in turn implies the possibility of using these position estimates as a virtual feedback to the controllers instead of using the actual sensor's feedback. System's global behavior can be investigated by monitoring lumped system dynamics, to guarantee the accomplishment of motion control task and the minimization of system's residual vibrations. Since the dynamics of the system can be obtained, the externally applied forces or torques can be estimated. The experimental results show the validity of the proposed algorithm and the possibility of using two actuator parameters in order to estimate the uniform system parameters, rigid system's position, flexible system's lumped mass positions and external disturbances due to system's interaction with the environment.