Method for evaluating minimum area of line profile error of cross section of skirt part of variable-ellipse piston

The invention discloses a method for evaluating a minimum area of a line profile error of a cross section of a skirt part of a variable-ellipse piston. The method comprises the following steps of: measuring and acquiring a coordinate of a measurement point on the cross section of the skirt part of the variable-ellipse piston at first, if the coordinate of the measurement point is a rectangular coordinate, converting the rectangular coordinate into a polar coordinate, and establishing a model for evaluating the minimum area of the line profile error of the cross section of the skirt part of the variable-ellipse piston; then randomly producing an initial position and an initial speed of a particle, calculating a target function value of the particle according to the initial position of the particle and a measured value of the cross section line profile, and determining a partial optimal particle and a whole optimal particle; and modifying the speed of the particle and changing the position of the particle by an enrichment factor method, updating the position of the particle optimal particle and the position of the whole optimal particle by using the changed position of the particle, and when a predetermined terminating condition is achieved, outputting a minimum area answer, the optimal parameter value and the ovality of the line profile error of the cross section of the skirt part of the variable-ellipse piston. By the method, the minimum area answer, the optimal parameter value and the ovality of the line profile error of the cross section of the skirt part of the variable-ellipse piston can be calculated at the same time.