Zhao Zhuoqun, Wang Jiang, Zhao Hui
School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, China.
School of Mechanical Engineering, Tianjin Sino-German University of Applied Sciences, Tianjin 300350, China.
Sensors (Basel). 2023 Aug 11;23(16):7133. doi: 10.3390/s23167133.
Aiming at the time-varying uncertainties of robot and camera models in IBUVS (image-based uncalibrated visual servo) systems, a finite-time adaptive controller is proposed based on the depth-independent Jacobian matrix. Firstly, the adaptive law of depth parameters, kinematic parameters, and dynamic parameters is proposed for the uncertainty of a robot model and a camera model. Secondly, a finite-time adaptive controller is designed by using a nonlinear proportional differential plus a dynamic feedforward compensation structure. By applying a continuous non-smooth nonlinear function to the feedback error, the control quality of the closed-loop system is improved, and the desired trajectory of the image is tracked in finite time. Finally, using the Lyapunov stability theory and the finite-time stability theory, the global finite-time stability of the closed-loop system is proven. The experimental results show that the proposed controller can not only adapt to the changes in the EIH and ETH visual configurations but also adapt to the changes in the relative pose of feature points and the camera's relative pose parameters. At the same time, the convergence rate near the equilibrium point is improved, and the controller has good dynamic stability.
针对基于图像的未标定视觉伺服（IBUVS）系统中机器人和相机模型的时变不确定性，提出了一种基于深度无关雅可比矩阵的有限时间自适应控制器。首先，针对机器人模型和相机模型的不确定性，提出了深度参数、运动学参数和动力学参数的自适应律。其次，采用非线性比例微分加动态前馈补偿结构设计了有限时间自适应控制器。通过将连续非光滑非线性函数应用于反馈误差，提高了闭环系统的控制质量，并在有限时间内跟踪图像的期望轨迹。最后，利用李雅普诺夫稳定性理论和有限时间稳定性理论，证明了闭环系统的全局有限时间稳定性。实验结果表明，所提出的控制器不仅能够适应EIH和ETH视觉配置的变化，还能适应特征点相对姿态和相机相对姿态参数的变化。同时，提高了平衡点附近的收敛速度，控制器具有良好的动态稳定性。
