Inertial stabilization of a sensor mounted on nonstationary platforms is an important task in many applications such as image processing, astronomical telescopes, and tracking SYSTEMs. For this purpose, some type of GIMBALing arrangements is typically used. For implementing the LOS stabilization, usually a two-axes GIMBAL SYSTEM is used which the sensor is mounted in the inner GIMBAL. The dynamic modeling and designing the control SYSTEM for two axes GIMBAL SYSTEM have been studied extensively, but there is a few works on three axes GIMBAL SYSTEM. In this paper, the equation of motion for a three axes GIMBAL SYSTEM is derived by the moment equation. The effect of angular velocities of the base into the GIMBALed dynamic SYSTEM and cross-coupling between GIMBALs are presented. In addition, some critical notes are presented for constructing the GIMBAL assembly. Moreover, a model based control strategy is proposed for controlling the GIMBAL dynamics.

The GIMBAL stabilization mechanism is used to provide the stability to an object mounted on the GIMBAL by isolating it from the base angular motion and vibration. The purpose of this paper is to present a model of control servo SYSTEM for one axis GIMBAL mechanism using a cascade PID controller. The GIMBAL torque relationships are derived by taking into consideration the base angular motion. The conventional PID controller and three cascade controller structures are investigated. The servo control loop is built and modelled in MATLAB/Simulink using these controllers. The simulation results are compared and the servo SYSTEM performance is analysed for each controller in terms of performance criteria. The comparison results prove that a further improved SYSTEM performance is achieved using I-PD controller as compared to the SYSTEM performance obtained when the other controllers are utilized. The paper’s value lies in designing the servo control SYSTEM using a modified controller composed of two parallel I-PD controllers related with a switch depend ing on the base angular rate as a threshold. The results show that the modified SYSTEM satisfies the desired servo SYSTEM requirements.