The trackability limitation of current gradient algorithm is discussed.A new algorithm, named variable parameter gradient estimation algorithm with local polynomial approximation is proposed.
For the other four leaf shapes - spathulate, denta-spathulate, cello-shaped and deltoid - more segments of Bezier curves were necessary for a good fitting.
In order to further discuss the identification of fault after the detection, a nonlinear online neural network approximator is used to provide an estimate of the fault.