In many optical trapping experiments, exogenous forces are estimated by assuming the exogenous force is balanced with the optical force. These optical forces are measured using Hooke’s law, and the displacement of the particle is low-pass filtered to minimize the effects of Brownian noise. This paper explores a different approach that uses a disturbance model approach for estimating exogenous forces using a Kalman filter. The state estimate is then used in a LQG structure to manipulate the relative position of a dielectric particle within an optical trap. The exogenous force estimate using a Kalman filter has been shown to have a higher SNR than the force estimation using Hooke’s Law. In addition to force estimation, the control structure can also manipulate the relative displacement of the particle to satisfy experimental conditions. A simulation is presented to demonstrate the performance of the LQG control structure.
Integrated control/structure optimization by multilevel decomposition
