Control Of JDAM's Electromechanical Actuator

JDAM, which is a family of inexpensive, precision-guided munitions, plays an important role in modern warfare. Therefore, the study of the munitions is significant.The EMA of JDAM must be small size, large output moment, high precision, digital, modular. In this paper, the EMA of JDAM is the plant. According to the system requirements, the paper determines the structure and composition of EMA. Then the paper creates a mathematical model, and analyses carefully the rudder hinge moment.Precision-guided munitions flight the much shorter-range than missile, the corresponding adjustment time is short. So the accuracy, speed is the feature of ammunition, and the basic requirements of servo performance. For variable structure control with fast response, the parameter variations and external disturbances is not sensitive, no need to on-line identification, simple implementation, the paper design to meet system performance requirements of the terminal sliding mode control, combined with practical servo control system needs to solve the outstanding problems. Because of the upper bound of the parameter uncertainty and disturbance is difficult to obtain, the adaptive law is applied to estimate the value. The appropriate Lyapunov function is selected to prove the stability of the improved closed-loop system. The control law is improved by approximation saturation function, because of the vibration of variable structure control. Then, the results of numerical simulation prove the control law.According to the general requirements of EMA structure, critical components are designed and verified. 3D software is used to modal and analyse the components. Using traditional method of bevel gear, tooth contact fatigue strength and tooth root bending fatigue strength are analyzed. Analyze the static and dynamic modal of the key axis with ANSYS. That analysis of the system axis at the nodal displacement under load and vibration mode provides the safe operation of the system guidance.