基于四元数反馈的UVMS滑模控制器设计

Sliding Mode Controller Design Based on Quaternion Feedback for UVMS

随着水下机器人-机械手系统(UVMS)向轻量化、敏捷化方向发展,对高精度水下姿态控制的需求日益突出。传统方法多使用欧拉角表示姿态,其在特殊姿态下求运动学逆解会产生奇异,不能满足特殊姿态作业的要求。因此,文中采用四元数表示水下机器人本体姿态,建立基于四元数的运动学模型,避免了欧拉角的万向锁问题。同时,进一步构建了UVMS的动力学模型,构造基于四元数误差的滑模面,设计了位置、姿态滑模控制器,并通过广义Lyapunov理论分析了系统的稳定性。为了实现更好的控制效果,利用时间误差绝对值函数设计适应度函数,采用遗传算法优化了控制器参数。仿真结果验证了控制器的有效性。

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 represen tation.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.