In order to solve the problem that control system of permanent magnet synchronous motor (PMSM) is difficult meet high accuracy due influence non-repeated disturbances such as external disturbance, parameter variation, and friction force during operation, a novel sliding mode (NSMC) method based on tracking differentiator (TD) radial basis (RBF) neural network was proposed. Firstly, new reaching...

Spacecraft simulators are widely used to study the dynamics, guidance, navigation, and control of a spacecraft on the ground. A spacecraft simulator can have three rotational degrees of freedom by using a spherical air-bearing to simulate a frictionless and microgravity space environment. The moment of inertia and center of mass are essential for control system design of ground-based three-axis...

Back-stepping design method is widely used in high-performance tracking control tasks As known to all, the controller based on back-stepping will become complex as model order increases, which so called “explosion of terms” problem. In this paper, a differentiator (TD) proposed handle Instead calculating derivatives intermediate variables through tedious analytical expressions, for method, embe...

An arbitrary order differentiator that, in the absence of noise, converges to the true derivatives of the signal after a finite time independent of the initial differentiator error is presented. The only assumption on a signal to be differentiated (n−1)-times is that its n-th derivative is uniformly bounded by a known constant. The proposed differentiator switches from a newly designed uniform ...

In this paper, a continuous hybrid differentiator is presented based on a strong Lyapunov function. The differentiator design can not only reduce sufficiently chattering phenomenon of derivative estimation by introducing a perturbation parameter, but also the dynamical performances are improved by adding linear correction terms to the nonlinear ones. Moreover, strong robustness ability is obtai...

Abstract: In this paper, describing function method is used to analyze the characteristics and parameters selection of differentiators. Nonlinear differentiator is an effective compensation to linear differentiator, and hybrid differentiator consisting of linear and nonlinear parts is the combination of both advantages of linear and nonlinear differentiators. The merits of the hybrid differenti...

Abstract: This paper presents a high-order differentiator for delayed measurement signal. The proposed differentiator not only can correct the delay in signal, but aslo can estimate the undelayed derivatives. The differentiator consists of two-step algorithms with the delayed time instant. Conditions are given ensuring convergence of the estimation error for the given delay in the signals. The ...

A tunable temporal photonic fractional differentiator using a silicon-on-isolator (SOI) electrically tuned microring resonator (MRR) is proposed and experimentally demonstrated. Through changing the voltage applied on the MRR, the fractional order of the photonic differentiator can be continuously tuned. The proposed fractional-order differentiator is demonstrated experimentally with Gaussian p...