This article presents a finite-time equivalent-input- disturbance (FTEID) approach that estimates the EID in a finite time. A finite-time state observer and a finite-time EID estimator ensure the finite-time convergence of the EID estimation and make improvement for the disturbance-rejection performance of a control system. The FTEID-based control system is divided into three subsystems for stability analysis and an algorithm is carried out to design gains of state feedback and finite-time observer. The effectiveness and superiority of the FTEID approach are verified by experiments of a Stewart-platform control system.

This paper presents a new non-contact alternating current impedance instrument (NCACII) with multiple frequencies to measure the electrical impedance during the hydration of cement-based materials. It implements two measurement techniques: the first technique is a frequency conversion measurement with a frequency variation range of 1–100 kHz. The second is to measure the variation in impedance with time. It provides a new way to analyze the pore structure of cement-based materials. In this instrument, we design a current sensor made from nanocrystalline T37. The experimental results demonstrate the detection accuracy of NCACII has been improved and indicates the superiority of nanocrystalline T37.

In the vector control system of a tubular oscillating permanent magnet synchronous linear motor, it is difficult to obtain accurate feedback information from the conventional mechanical sensors under bad and complex working conditions. This paper presents a new predictive current control designed to estimate the speed of the tubular oscillation permanent magnet synchronous linear motor. It implements two control techniques: The first technique is using the sliding-mode observer’s speed observer for speed estimation. The second is to design a deadbeat predictive current control to replace the PI regulator in the conventional current loop; it solves the difficulties of global optimization and PI parameter setting. The simulation and experimental results show that this method gives a good dynamic performance.