Takagi-Sugeno Fuzzy Control for the Semi-active Seat Suspension with an Electromagnetic Damper

2019 IEEE. In this paper, a state observer-based Takagi-Sugeno (TS) fuzzy controller is proposed for a semi-active seat suspension installed with an electromagnetic damper (EMD) system. Due to the nonlinear and hysteresis characteristics of the seat suspension friction, the control system design for seat suspension is difficult. Therefore, the Bouc-Wen friction model is applied to represent the seat suspension friction force and this nonlinear model is linearized by using TS fuzzy approach at first. Then a H∞ controller that considers the seat suspension performance requirements is designed. It is noticed that not all the state variables are measurable in practice, a state observer is designed based on the measurement variables. Finally, two typical excitation are applied to validate the effectiveness of the proposed controller and a tuned passive suspension is also simulated for comparison

Friction observer-based hybrid controller for a seat suspension with semi-active electromagnetic damper

This paper proposes a hybrid controller for a seat suspension equipped with an advanced electromagnetic damper (EMD) system to meet the requirement with vibration isolation and energy saving. The friction of seat suspension has considerable influence on the system dynamic. Applying a constant model to describe the friction is unreliable due to the long term wear and tear. Therefore, an observer is designed to estimate seat suspension friction, and it is used to compensate for the frictional influence in a H controller. The friction observer applies the acceleration, relative displacement and circuit current, which are measurable in engineering. Then, a hybrid controller is further proposed, in which the low-frequency vibration is controlled with the friction observer-based H controller, and the system will switch to passive state with low damping at high frequency based on the dominant frequency of the vibration. In order to validate the effectiveness of the proposed friction observer, the Bouc-Wen friction model is selected to describe actual seat suspension friction, and it is compared with the estimated friction by the observer. Experimental results show that the friction observer has similar performance and less computational complexity compared with the Bouc-Wen friction model. The effectiveness of the proposed hybrid controller is validated on a six-degree of freedom vibration platform with the bump and random excitation. This friction observer-based hybrid controller is helpful for the engineering application as it applies practically measurable variables as feedback and considers the performance of the semi-active device in reality. ∞

A Ring-Type Triboelectric Nanogenerator for Rotational Mechanical Energy Harvesting and Self-Powered Rotational Speed Sensing

In recent years, sensors have been moving towards the era of intelligence, miniaturization and low power consumption, but the power-supply problem has always been a key issue restricting the popularization and development of machine-mounted sensors on the rotating machinery. Herein, we develop a ring-type triboelectric nanogenerator (R-TENG) that functions as a sustainable power source as well as a self-powered rotational speed sensor for rotating machinery. The R-TENG adopts a freestanding mode and consists of a ring-type container unit, an end cover and polytetrafluoroethylene (PTFE) cylinders. In this study, the influence of the number of cylinders, the PTFE cylinder’s diameter and the rotational speed on the electrical output are systematically examined, and the motion law of the PTFE cylinders in the container is revealed by the experimental results and verified by kinetic simulation. At a rotational speed of 400 rpm, the output voltage, current and transferred charge of the designed R-TENG reached 138 V, 115 nC and 2.03 μA, respectively. This study provides an attractive power supply strategy for machine-mounted sensors of the rotating machinery, and the rotational speed measurement test also suggests the potential application of the R-TENG as a self-powered rotational speed sensor

Effects of antimony stress on growth, structure, enzyme activity and metabolism of Nipponbare rice (Oryza sativa L.) roots

Some antimony (Sb) contaminated areas are used for rice cultivation in response to economic demands. However, little is known about the effects of Sb stress on the growth and metabolism of rice roots. Thus, a hydroponic experiment was carried out on the growth, root anatomy, enzyme activity, and metabolism of Nipponbare rice (Oryza sativa L. ssp. japonica cv. Nipponbare) under varying levels of Sb (III) stress (0 mg L−1, 10 mg L−1, and 50 mg L−1). With the increase of Sb concentration, rice root length and root fresh weight declined by 67.8 % and 90.5 % for 10 mg L−1 Sb stress and 94.1 % and 98.4 % for 50 mg L−1 Sb stress, respectively. Anatomical analysis of cross-sections of Sb-treated roots showed an increase in cell wall thickness and an increase in the number of cell mitochondria. The 10 mg L−1 and 50 mg L−1 Sb stress increased the activity of enzyme superoxide dismutase (SOD) in root cells by 1.94 and 2.40 times, respectively. Compared to the control, 10 mg L−1 Sb treatment increased the activity of catalase (CAT) and peroxidase (POD), as well as the concentrations of antioxidant glutathione (GSH) in the root by 1.46, 1.38, and 0.52 times, respectively. However, 50 mg L−1 Sb treatment significantly decreased the activity or content of CAT, POD and GSH by 28.1 %, 13.5 % and 28.2 %, respectively. Nontargeted LC/MS-based metabolomics analysis identified 23 and 13 significantly differential metabolites in rice roots exposed to 10 mg L−1 and 50 mg L−1 Sb, respectively, compared to the control. These differential metabolites were involved in four main metabolic pathways including the tricarboxylic acid cycle (TCA cycle), butanoate metabolism, alanine, aspartate and glutamate metabolism, and alpha-linolenic acid metabolism. Taken together, these findings indicate that Sb stress destroys the structure of rice roots, changes the activity of enzymes, and affects the metabolic pathway, thereby reducing the growth of rice roots and leading to toxicity

Advances in Marine Self-Powered Vibration Sensor Based on Triboelectric Nanogenerator

With the rapid development of advanced electronics/materials and manufacturing, marine vibration sensors have made great progress in the field of ship and ocean engineering, which could cater to the development trend of marine Internet of Things (IoT) and smart shipping. However, the use of conventional power supply models requires periodic recharging or replacement of batteries due to limited battery life, which greatly causes too much inconvenience and maintenance consumption, and may also pose a potential risk to the marine environment. By using the coupling effect of contact electrification and electrostatic induction, triboelectric nanogenerators (TENGs) were demonstrated to efficiently convert mechanical vibration movements into electrical signals for sensing the vibration amplitude, direction, frequency, velocity, and acceleration. In this article, according to the two working modes of harmonic vibration and non-harmonic vibration, the latest representative achievements of TENG-based vibration sensors for sensing mechanical vibration signals are comprehensively reviewed. This review not only covers the fundamental working mechanism, rational structural design, and analysis of practical application scenarios, but also investigates the characteristics of harmonic vibration and non-harmonic vibration. Finally, perspectives and challenges regarding TENG-based marine self-powered vibration sensors at present are discussed