Failure detection schemes in control actuation systems for launch vehicles

Abstract

Control actuation systems are used for the attitude control of launch vehicles. They are basically closed loop position servo systems by means of which the engine or nozzle of the rocket is vectored based on the commands coming from onboard computer. The two important elements of a typical control actuation system are the control electronics and the actuators. Control electronics plays a vital role in the success of a launch vehicle mission. To avoid single point failures and hence, to improve the reliability of the system, various redundancy schemes are used in control actuation systems. The main factors to be considered for selection of redundancy scheme are the increase in weight, size, improvement in reliability, etc. In this paper, a case study of a typical dual redundant electromechanical control actuation system is highlighted. Various redundancy schemes were studied considering their merits and complexity of implementation. The configuration chosen ensures lesser switchover transient and has less complexity compared to triple and quad redundant systems. A dual redundant controller in active standby mode is realised and the test results are attached.