Dual-redundancy smart rotating speed sensor design for unmanned helicopter

For the complex condition of unmanned helicopter and its high requirements of reliability, a dual-redundancy smart rotating speed sensor is proposed using hardware and software redundancy. It is composed of two MCUs(Micro Control Units), dual-port RAM(Random Access Memory), pulse signal generator circuitry, logic circuitry, CAN(Controller Area Network) bus interface and so on, and can be applied to distributed control system of unmanned helicopter. The sensor's reliability is improved by two channels which detect and backup each other. The experiment indicates that the reliability and real-time response of the dual-redundancy smart rotating speed sensor is satisfactory and the relative error of rotating speed measurement is less than 0.5%. The dual-redundancy smart rotating speed sensor can switch exactly and send alarm signals when there are malfunctions..