Improved quasi-Newton algorithm for the optimal coil design problem

摘要

In this work the problem of designing the optimal coil for the homogeneous magnetic field excitation is considered. Such coils are used for example in the magnetic resonance imaging systems. The studied problem formulation belongs to the class of the box-constrained non-linear optimization problem. This kind of optimization problem requires calling the objective function many times and in consequences it is very time consuming to get optimal solution. Author proposes splitting the optimization problem into the smaller one. First the optimization process is done for very low dimension. Then using the spline function the space of the possible solutions is increased, and the increased solution becomes an initial point for the new optimization step. The quasi-Newton optimization method is used to solve nonlinear optimization problem. Several design examples are presented.