Calibration of angular displacement sensor of vehicle rudders based-on vision measurement technology

A non-contact calibration method for angular displacement sensor of aileron, flap, rudder and elevator for vehicle based on computer monocular vision is proposed. A calibration target, made up of double feature circle of co-plane, was attached on the airplane's rudder. The digital image was acquired by using a digital camera to take pictures of the double-circle calibration target, The position and. length of perspective projection for center of circle and diameter of the feature circle were identified by digital image processing. A set of coordinates calculation equations between the object space and the image space were set up according to reverse perspective projection transformation, and equation of plane of the calibration target was educed. So, the angular displacement of the vehicle s rudder was expressed by direction cosine of the target's plane. Simulation and experiment were carried out to verify the method, the result shows that the method have some benefits as time-saving, operation-simple and with high accuracy, and free from calibrating interior and exterior parameter in advance. The error of angle displacement calibration is less than 0.2°.