Fitting method for pump complex characteristic curve based on B-spline

A fitting method for pump complex characteristic curve with large deflections and non-equidistant data points based on cubic uniform B-spline is presented.New virtual data points are introduced when any spire point is detected in the curve,which is divided into several sections with simple shapes.The optimal knots ordinates and Abscissas within the specified distribution ranges are searched employing sequential optimization method in the least square sense.It is proved in the examples that the new method works well in precisely building the pump test data in wide area into smooth curve without disturbance caused by the random test error.