This article proposes an unknown system dynamics estimator (USDE) based sliding mode control for servo mechanisms with and modeling uncertainties. An invariant manifold is first constructed by introducing auxiliary variable on a first-order low-pass filter. used to design USDE only one tuning parameter (i.e., time constant the filter) simpler structure than other estimators. The compensate effect of lumped since it can be easily incorporated into synthesis. Moreover, avoid chattering...

In this article, a fuzzy adaptive nonsingular fixed-time attitude tracking control scheme is proposed for the quadrotor unmanned aerial vehicles (UAVs) subject to inertia uncertainties, actuator saturation, and faults. A new sliding mode surface an auxiliary function are constructed, such that singularity problem can be avoided in controller design without using any piecewise continuous functions. Then, novel arccot function-based double power reaching law developed adjust gain enhance...

Currently, radical gastrectomy for gastric cancer is usually combined with lymph node tracing technology to ensure the complete removal of metastatic nodes. Our case demonstrates that bismuth compounds may be useful as tracers in gastrectomy. A 37-year-old man who was confirmed diagnosis found have black-stained nodes during surgical resection. The patient's medication history, pathological analysis and Inductively coupled plasma mass spectrometry (ICP-MS) presence dark particle deposited...

In this paper, the parameter identification and control problem are investigated for a mechanical servo system with LuGre friction. First of all, an intelligent glowworm swarm optimization (GSO) algorithm is developed to identify friction parameters. Then, by using finite-time estimate law nonlinear sliding mode technique, adaptive (NSMC) based on GSO designed speed up convergence decrease overshoot steady-state time in process. Finally, comparative simulations given show that proposed...

This paper proposes a novel continuous reaching law for chattering-free sliding mode control by using two hyperbolic functions with similar changing rate and opposite amplitude characteristics. The first function is an inverse sine function, which can guarantee the fast convergence as initial value of variable far away from equilibrium. When approaching to zero, second tangent ensure be infinitely close zero rather than cross zero. With proposed law, property both guaranteed, satisfactory...

Abstract This article proposes a neural‐network‐based adaptive finite‐time output constraint control scheme for attitude stabilization of rigid spacecrafts. First, novel singularity‐free terminal sliding mode variable is constructed and an auxiliary function developed in the controller design to avoid singularity problem. Then, neural law designed approximate lumped uncertainty spacecraft system including inertia uncertainties external disturbances. Furthermore, prescribed performance...

In this paper, a speed tracking and synchronization control approach is proposed for multimotor system based on fuzzy active disturbance rejection (FADRC) enhanced adjacent coupling scheme. By employing logic rules to adjust the coefficients of extended state observer (ESO), FADRC presented guarantee performance enhance robustness against external parametric variations. Moreover, an strategy simplify structure controller through introducing into conventional approach. Based scheme, adaptive...

In this paper, an improved adjacent coupling control scheme combined with integral sliding mode (ISMC) and active disturbance rejection (ADRC) techniques is proposed for multiple motors synchronization. The whole synchronous system divided into two parts. For the first part, a speed synchronization controller designed based on (ISMC), developed by introducing cofficients, which can enhance performance of motors. second technique employed design tracking to guarantee strong robustness high...

In this work, the position and attitude tracking finite-time adaptive control problem of a type vertical take-off landing (VTOL) aircraft system is studied. Here, dynamic VTOL subjected to external disturbances unknown nonlinearities. Firstly, radial basis function neural networks are introduced approximate these nonlinearities, weight update laws proposed replace ideal weights. Secondly, for errors generated in approximation process system, parameter presented. After that, based on designed...

In this paper, an active disturbance rejection control (ADRC) scheme combined with phase-locked loop (PLL) is proposed for sensorless speed of the permanent magnet synchronous motor (PMSM) system. The extended state observer (ESO) employed to estimate back electromotive force (EMF), and a PLL designed based on trigonometric function extract rotor signal. Then, ADRC basis estimated ensure that accurate performance. Simulation results show effectiveness method.

In this paper, the parameters identification and control problem is investigated for a mechanical servo system with LuGre friction. First of all, an intelligent glowworm swarm optimization algorithm developed to identify friction parameters. Then, adaptive based on (AC+GSO) designed by using finite-time parameter estimate law speed up convergence. Finally, comparative simulations are given show that proposed technique effective high tracking performance.

Abstract This paper presents a finite-time command-filtered approximation-free attitude tracking control for rigid spacecraft. A novel prescribed performance function (FTPPF) is first constructed to ensure that the errors converge predefined region in finite time. Then, error compensation mechanism and incorporated into backstepping design, such differentiation of virtual signals recursive steps can be avoided overcome singularity issue. Compared with most approximation-based methods, less...

In this paper, a design method of sliding controller with the disturbance observer is proposed for existence and parameter perturbation in electromechanical servo system, switch function, gain control function are given, At same time, stability analysis made by means Lyapunov function. The designed has lower , so chattering mode reduced greatly. Moreover, compensated quickly. Simulations verified that better dynamic performance robust capability, also it decided advantage over conventional...

In this paper, an adaptive tracking control scheme is proposed for robotic manipulators with unknown input saturation. To overcome the design difficulty from non-differential saturation nonlinearity, a smooth nonlinear function of signal first introduced to approximate function, which can be further transformed into affine form according mean-value theorem. Then, simple sigmoid neural network employed uncertain parts including in system. By combing backstepping technique and sliding-mode...

In this paper, a universal control scheme is investigated for class of nonlinear systems with unknown parameters and nonlinearities like friction, dead-zone, etc. First all, an adaptive finite-time update law developed to estimate the by introducing auxiliary filtered variables system states regressor matrix. Then, controller proposed based on parameter estimation guarantee globally asymptotic stability system. Finally, motor servo friction given as example show effectiveness method.

In this paper, a composite integral terminal sliding mode surface is developed, and an adaptive synchronization control scheme proposed accordingly for multiple robotic manipulators with actuator saturation. By combining the terms, presented able to reduce static tracking errors improve performance. Moreover, system uncertainties, external disturbances effect of input saturation are compensated by designing update laws. The finite-time stability whole proved via Lyapunov analysis. Finally,...

Control network takes responsibility for data communication in the networked control system (NCS), so media access of is key to guaranteeing efficiency system. The paper presents a novel variable priority token passing manner network. theoretical analysis, mathematical analysis and experiments are given on after other. Comparison from shows high advantage presented than that CSMA/CD standard token-passing.

This paper proposes an adaptive tracking control scheme for voltage-driven robotic manipulators with output constraints to achieve satisfactory performance. To overcome the design difficulty from constraints, a tangent boundary Lyapunov function (tBLF) is first introduced keep errors remain within allowable range of constraints. Then, RBF neural networks are employed approximate uncertainties in system, and differentiator (TD) applied obtain differentiation virtual laws back stepping design....

To improve the ability of anti-interference and robustness planar motors, this article proposed a proportional-derivative (PD) position control method using nonlinear extended state observer (NESO). Firstly, dynamic model motor is given. And then, lumped disturbance system observed by developed observer, in which parameters are committed to ensuring stability NESO. The compensated output PD controller, enhance suppression system. Moreover, simulation results prove that can effectively...