Integrated Development of Target Aiming System for Heavy Weight 2-Axis Gimbal Turret

This study develops the integrated target aiming system (ITAS) of heavy weight 2-axis gimbal (2AG). ITAS needs the three parts such as target tracking part and stabilization part, roll compensation part. The target tracking part generates the angular rate command to track the moving target. The stabilization part eliminates the rotational disturbance when the mobile vehicle drives on the street or track defined in test operational procedure (TOP). The roll compensation part generates the angular rates for yaw and pitch axis to remove the roll disturbance. The 2-axis gimbal structure cannot directly remove the roll disturbance to maintain the aiming point when the vehicles moves because the it do not include the actuator of roll rotation due to limitation of weight and power supply. Therefore, this research designs the three parts by analyzing dynamics. First, the motion equation of 2AG is defined by applying the constraints to 3 degrees of freedom (DOF) motion equation to define the control technique. Second, the target tracking controller is designed by using classical position controller and smith-predictor to minimize the time delay effect due to image processing time. It outputs the angular rate command with respect to inertia coordinate for stabilization controller. Third, the stabilization controller is designed to automatically reduce the rotational disturbance of yaw and pitch axis by tracking the given angular rate command generated by target tracking controller. The stabilization controller is developed as dual loop system. The inner loop and the outer loop use the encoder sensor and the inertial measurement unit (IMU) sensor, respectively. The inner loop using the encoder sensor generates the torque command including friction compensation by tracking the given angular rate command made by outer loop. The outer loop using the IMU sensor tracks the given command generated by target tracking controller and computes the angular rate command with respect to vehicle coordinate to remove the rotational disturbance measure by IMU sensor. Fourth, the roll compensator is developed to improve the performance of target aiming system. The roll compensator outputs the angular velocities commands for the yaw and pitch axes to eliminate the roll disturbance. Finally, the performance of proposed system is checked by 6-DOF simulator and the remotely controlled weapon station (RCWS). The disturbance profile for 6-DOF simulator is measured by small tactical vehicle (STV) including RCWS.