考虑全状态约束和扰动的机械臂神经网络控制

Neural Network Control of Robotic Arm Considering Full-state Constraints and Disturbances

  • 摘要: 针对具有全状态约束、有界未知扰动和动态不确定性的机械臂跟踪控制问题,本文利用正切型障碍李雅普诺夫函数,提出了考虑全状态约束和有界扰动的机械臂自适应神经网络控制。位置误差采用时变约束,速度误差采用静态约束。在虚拟控制设计中引入时变类比例-积分(PD)项,加快了系统的响应速度。考虑并抑制机械臂末端搬运物体而未固定好的有界扰动,采用自适应神经网络来处理机械臂系统的不确定性,即使在外部扰动和未知动态下也能保证满足预定义的状态约束。引入摩尔-彭罗斯逆并基于李雅普诺夫理论证明闭环系统信号最终有界。对比仿真结果表明了所提方法响应速度快、跟踪误差小、鲁棒性强的优越性。在Franka Emika Panda机器人上的实验结果验证了所提方法的有效性。

     

    Abstract: To address the tracking control challenges of robotic arms faced with full state constraints, bounded unknown disturbances, and dynamic uncertainties, we propose an adaptive neural network control strategy that employs tangent-type barrier Lyapunov functions to manage full state constraints and bounded disturbances. Time-varying constraints are applied to position errors, while static constraints handle velocity errors. A time-varying class PD term is introduced in the virtual control design to speed up system response. To address and suppress the bounded disturbances caused when the end of the robotic arm carries an object without fixing it well, an adaptive neural network is used. This approach effectively deals with system uncertainties, ensuring that the robotic arm satisfies predefined state constraints even under external disturbances and unknown dynamics. The Moore-Penrose inverse and Lyapunov stability theory are introduced to prove that the closed-loop system remains consistently bounded. Comparative simulation results demonstrate the method's advantages in achieving fast response speeds, small tracking errors, and strong robustness to full-state constraints. Experimental results on a Franka Emika Panda robot validate the effectiveness of the proposed method.

     

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