In this paper, a 3D jerk chaotic system with hidden attractor was explored, and the dissipativity, equilibrium, and stability of this system were investigated. The attractor types, Lyapunov exponents, and Poincare section of the system under different parameters were analyzed. Additionally, a circuit was carried out, and a good similarity between the circuit experimental results and the theoretical analysis testifies the feasibility and practicality of the original system. Furthermore, a robust feedback controller was designed based on the finite‐time stability theory, which guarantees the synchronization of 3D jerk master‐slave system in finite time and asymptotically converges to the origin. Finally, we also give verification for the discussion in this paper by numerical simulation.

This paper concentrates on the predefined‐time trajectory tracking for an uncertain robotic manipulator system. First, a modified predefined‐time control (PTC) algorithm is proposed. Subsequently, with the help of proposed modified PTC algorithm and the nonsingular design method of terminal sliding mode, a novel nonsingular terminal sliding‐mode control (NTSMC) scheme is proposed for ensuring the predefined‐time convergence of tracking errors. The advantages of the newly proposed control scheme are as follows. (i) Unlike the conventional predefined‐time sliding‐mode control (SMC) which only guarantees the predefined‐time convergence of sliding‐mode surface, the proposed scheme can guarantee the predefined‐time convergence of tracking errors. (ii) Compared with the conventional PTC algorithm, the proposed modified PTC algorithm can reduce the initial control peaking and enhance the precision of convergence time. The performance and effectiveness of the proposed control scheme are illustrated by comparing with the existing methods.

In this paper, a microfiber knot resonator (MKR) was encapsulated in polydimethylsiloxane (PDMS), and its capability to sense temperature was experimentally evaluated. A very high sensitivity of -12 nm/°C was recorded for the MKR device, with a microfiber diameter of 2μm and a ring diameter of 95 μm. However, light-loss was significant in the small MKR. We attribute this to the low ratio of ring-length to microfiber-diameter. A stable temperature-sensing performance and sensitivity of negative 8.48 nm/°C were obtained for the MKRs with a microfiber diameter of 3 μm and a ring diameter of 3 mm. A MKR device with a non-uniform microfiber (in diameter) was also fabricated and studied. This compact and miniature temperature-probe will be a promising candidate for wearable devices.

This paper proposes a novel robust fixed‐time control for the robot manipulator system with uncertainties. Based on the uniform robust exact differentiator (URED) algorithm, a robust control term is constructed. Then, a robust fixed‐time inverse dynamics control (IDC) is proposed. For the proposed control method, the fixed‐time stability of a closed‐loop system with uncertainties is strictly proved. The newly proposed method exhibits the following two attractive features. First, the proposed control scheme extends the existing fixed‐time IDC for the robot manipulator system to the robust control scheme. Second, the proposed method is strictly nonsingular rather than the commonly used approximate approach. Simulation result demonstrates the effectiveness of the proposed control scheme.