六自由度机械臂无模型自适应滑模控制

Model-free adaptive sliding mode control method for 6-DOF manipulator

针对强耦合、非线性的六自由度机械臂系统难以建立精确数学模型的问题,提出了一种无模型自适应滑模控制方案。以无模型自适应方法与滑模变结构控制相结合,利用全格式动态线性化方法,将机械臂非线性模型转换为离散的动态线性时变模型,采用各关节的输入力矩和输出角速度来设计控制器,并引入滑模控制保证其收敛性。通过六自由度机械臂的Sim Mechanics模型进行了仿真实验,结果表明,相比于现有的无模型自适应方案,即使在没有建立六自由度机械臂精确数学模型的情况下,所设计的控制方案能实现各关节对理想速度更加迅速的响应和更加精准的跟踪,从而验证了所提出的无模型自适应滑模控制方案的可行性和有效性。

Due to the strong coupling and nonlinearity,it is difficult to establish an accurate mathematical model for the six degrees of freedom manipulator systems. To solve this problem,a model-free adaptive sliding mode control scheme is proposed. The control scheme combined the model-free adaptive control method with the sliding mode variable structure control method. The full form dynamic linear method is used to transform the nonlinear model of the manipulator into a discrete dynamic linear time-varying model. The input torque and output velocity of each joint are used to design the controller. Then the sliding mode method is introduced to guarantee the convergence of the approach. The simulation experiments are conducted by a SimMechanics model of the 6-DOF manipulator. The simulation results show that even without the establishment of the accurate mathematical model of the 6-DOF manipulator,the proposed control scheme has faster response and better tracking performance to ideal speed of each joint than that of existing model-free adaptive control schemes. The final results also verify the feasibility and effectiveness of theproposed model-free adaptive sliding mode control solution.