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For the high precise tracking control purpose of a cable-driven manipulator under lumped uncertainties, a novel adaptive fractional-order nonsingular terminal sliding mode control scheme based on time delay estimation (TDE) is proposed and investigated in this paper. The proposed control scheme mainly has three elements, ie, a TDE element applied to properly compensate the lumped unknown dynamics of the system resulting in a fascinating model-free feature; a fractional-order nonsingular terminal sliding mode (FONTSM) surface element used to ensure high precision in the steady phase; and a combined reaching law with adaptive technique adopted to obtain fast convergence and high precision and chatter reduction under complex lumped disturbance. Stability of the closed-loop control system is analyzed with the Lyapunov stability theory. Comparative simulations and experiments were performed to demonstrate the effectiveness of our proposed control scheme using 2-DOF (degree of freedom) of a cable-driven manipulator named Polaris-I. Corresponding results show that our proposed method can ensure faster convergence, higher precision, and better robustness against complex lumped disturbance than the existing TDE-based FONTSM and continuous FONTSM control schemes. KEYWORDS adaptive control, cable-driven manipulator, fractional-order, nonsingular terminal sliding mode (NTSM), time delay estimation (TDE) 1396

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With the rapid development of healthcare and human‐machine interactions, there is a growing demand for flexible electronic skin to have a high sensitivity over a wide range. While current multilevel and hierarchical structures inspired by nature broadened the sensing range, the structural design still lacks systematic study. Hereby, an ordered multilevel microstructure is proposed, and the design strategy for performance regulation of piezoresistive pressure sensors is studied. Both microstructure height and spatial distribution are investigated systematically through simulation and experiments. The flexible piezoresistive pressure sensor is fabricated by combining a fast, cost‐effective laser marking technology, molding, and pneumatic spray. The fabricated sensors show high sensitivity (1.5 – 8.3 kPa−1) over a wide range (0.01 – 200 kPa), and have a detection limit of 10 Pa, a response time of below 70 ms, and a mechanical stability over 10 000 cycles. This design and fabrication strategy can be further optimized by combining advanced materials and fabrication systems, and is expected to be applicable for a wide range of flexible materials.

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