Dual backstepping adaptive switching control of parameterized unknown bounded uncertain system with uniform online tuning law

This article proposes a kind of dual backstepping recursive sequences adaptive switching control mechanism. This method realizes the accuracy and efficiency stable tracking control of the parameterized uncertain nonlinear system. First, a decoupled scheme is utilized to separate uncertain structure from the nonlinear system. The uncertain structure is parameterized reconstructed. Then two distinct backstepping sub-controllers accordance with accuracy control phase and coarse control phase are designed separately. The double different backstepping controllers based on variable structure saturation switching logic are combined into a mixed control mechanism. In addition a group of online adaptive tuning law as supplement is employed to evaluate the unknown bounded uncertain structure. With the appropriately designed switching logical scheme, the stable tracking of the closed-loop control system is realized. Compared with traditional method, the advantages of this novel mechanism introduced overcome the drawback of chatting in saturation switching, and protect the beneficial nonlinear properties to improve the tracking accuracy, further balance and alleviate the conflict between convergence accuracy and efficiency. Meanwhile the uniform tuning laws are designed in accordance with different saturation switching phase making up different control process requirements and compensate the unknown uncertainty. Finally, two simulation comparison examples of position tracking control are given to demonstrate the usefulness and potential of the novel design method.