Abstract
In this paper, a robust adaptive fuzzy proportional-derivative inverse dynamics decoupling control scheme with fuzzy-based linear extended state observer (FLESO) is presented and applied to the trajectory tracking control of a two degree-of-freedom (2-DOF) spherical motion mechanism (SMM). The dynamics of the SMM has the characteristics of multivariable nonlinearity, uncertainties and strong coupling. Uncertainties like the modeling errors and external disturbances affect the tracking performance, and coupling increases the difficulty of controller design and reduces the tracking precision. Therefore, a novel hybrid control scheme that is composed of a fuzzy proportional-derivative (FPD) feedback control with varying gains, inverse dynamic model-based feed-forward decoupling term, FLESO with varying bandwidth, and robust term is developed. The novel control strategy combines the advantages of simplicity and easy design of the FPD control, the effectiveness of the FLESO to handle the modeling errors and external disturbances, and the robustness of the robust term to estimation errors of the FLESO. First, introduce the structure of the SMM and establish the dynamic model. Second, the feed-forward decoupling principle is derived based on the inverse dynamic model. Then the FPD control with two-inputs and two-outputs is designed, whose rule base is derived by the phase plane method. The linear extended state observer is designed, whose bandwidth is tuned via the fuzzy logic system. Furthermore, the asymptotic stability of the proposed controller is proved by the Lyapunov theorem. Finally, the high tracking performance of the proposed controller is validated via both simulation and experiment results.
Highlights
Multi-DOF spherical motion generation devices, which are generally composed of at least two rotary motors and some intermediate connecting parts in serial or parallel form, have been widely applied in industry such as robotic joints and orienting devices [1]-[3]
We investigate a novel 2-DOF hydraulic spherical motion mechanism (SMM) which can accomplish a 2-DOF smooth spherical motion in a single joint [4]
There have been plenty of advanced control strategies to settle the control problems caused by nonlinearity, uncertainties and strong coupling, such as fuzzy logic control [5], [6], neural network control [7], [8] and sliding mode control [9] and so forth
Summary
Multi-DOF spherical motion generation devices, which are generally composed of at least two rotary motors and some intermediate connecting parts in serial or parallel form, have been widely applied in industry such as robotic joints and orienting devices [1]-[3]. Bian et al.: A Robust Fuzzy PD Inverse Dynamics Decoupling Control of SMM with FLESO control These motivate us to develop an efficient control strategy for the SMM to compensate for the model uncertainties and external disturbances, which can provide the satisfactory control performance, and has the simple structure and low computation. The inverse dynamic model-based feed-forward control with the simple structure is widely employed to linearize and decouple the nonlinear coupled systems [18], [19]. It requires a precision dynamic model and has no capability to handle the model uncertainties and external disturbances.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
