Sliding Mode Controller Design Based on Quaternion Feedback for UVMS

With the development of lightweight and agile undersea vehicle manipulator systems(UVMSs), the demand for high-precision underwater attitude control is becoming increasingly prominent. Euler angle is traditionally used to represent the attitude; however, an inverse kinematic solution under a special attitude results in a singularity when this representation is employed. As a result, the requirements of special operations cannot be fulfilled through this representation. In this study, therefore, the quaternion is used to represent the posture of the rigid body of an undersea vehicle, and a quaternion-based kinematics model is established to avoid the gimbal lock. Furthermore, a dynamic model for the UVMS, sliding mode surface based on quaternion error, and position and attitude sliding mode controller are established. The stability of the system is analyzed by the generalized Lyapunov theory. In order to achieve a better control effect, this study uses the function of integrate time absolute error(ITAE) to design the fitness function and uses the genetic algorithm(GA) to optimize the controller parameters. The simulation results verify the effectiveness of the controller.