To detect parts per billion(ppb)-level volatile organic compounds(VOCs) in automobiles, a pre-concentrator is generally needed for electronic noses(e-noses), which can enrich ppb-level concentration to parts per...
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To detect parts per billion(ppb)-level volatile organic compounds(VOCs) in automobiles, a pre-concentrator is generally needed for electronic noses(e-noses), which can enrich ppb-level concentration to parts per million(ppm) level. However, the current e-nose chamber structure could dilute the pre-concentrated gases and then the detection performance is reduced. To solve this problem, a novel chamber design was proposed in this paper. The core design idea was to reduce the space for the gas flow in the chamber, taking into account the shape and size of the gas sensors. Specially, for the pin-type gas sensors, a series of cylindrical structure design was adopted, and for the micro-electro-mechanical system(MEMS) patch-type sensors, the headspace was compressed. The results of computational fluid dynamics(CFD) based simulation showed that the concentration of pre-concentrated gases in the novel chamber was higher than that of the traditional chamber. The designed chambers were manufactured using polylactic acid(PLA) material by 3D printing. Experimental gases were prepared from polyurethane(PU) leather and polyvinyl chloride(PVC) leather to verify the performance of the chambers, and the results demonstrated that the proposed new e-nose chamber was superior to the traditional one in terms of the pre-concentration effect, repeatability and classification performance.
To achieve vertical profile exploration of deep-sea hybrid structures, a multi-joint autonomous underwater vehicle(MJ-AUV) with the orthogonal joints structure was designed, and its virtual prototype was built using A...
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To achieve vertical profile exploration of deep-sea hybrid structures, a multi-joint autonomous underwater vehicle(MJ-AUV) with the orthogonal joints structure was designed, and its virtual prototype was built using Automatic Dynamic Analysis of Mechanical systems(ADAMS). This paper focuses on the attitude control of the designed MJ-AUV which is a nonlinear system with strong coupling, big hysteresis, large inertia, and time-varying disturbance. According to the special structure of the MJ-AUV, an error based variable gain linear active disturbance rejection controller(EVG-LADRC) was proposed and compared with the traditional proportional-integral-derivative(PID) controller and LADRC. Simulation results demonstrated that EVG-LADRC outperformed the PID and LADRC in terms of rapidity, anti-interference, and accuracy.
Shape memory alloys (SMAs) are widely used as actuators to construct various robotics systems, such as, minimally invasive surgery robots, micro in-pipe robots and biomimetic micro robots. However, the nonlinear hyste...
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ISBN:
(数字)9781728164793
ISBN:
(纸本)9781728164809
Shape memory alloys (SMAs) are widely used as actuators to construct various robotics systems, such as, minimally invasive surgery robots, micro in-pipe robots and biomimetic micro robots. However, the nonlinear hysteresis behaviors in SMA actuators seriously degrade the control accuracy and desired performances of SMA-actuated controlsystems. In this paper, an experimental platform based on SMA actuator is conducted. To make the platform capable of achieving precise control, the complex hysteresis characteristics of the SMA actuators are studied. The SMA actuator in this study exhibits complicated nonlinear properties with saturation nonlinearity and asymmetric hysteresis influenced by both the duty cycle of the input voltage and the load mass, which are different from the classical rate-dependent hysteresis behaviors. To explore the nonlinear properties of the SMA actuated system, open-loop experiments under different duty cycles and loads are testified, and a modified Rate-dependent Prandtl-Ishlinskii (RDPI) model is developed to enhance modeling abilities. Fitting effects of the modified RDPI model is validated by the comparison between the modeling output and experimental data.
Piezoelectric actuators have been attached more importance in the field of high-precision micro actuating due to their excellent performance. However, the presence of the hysteresis nonlinearity and input saturation p...
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ISBN:
(数字)9781728164793
ISBN:
(纸本)9781728164809
Piezoelectric actuators have been attached more importance in the field of high-precision micro actuating due to their excellent performance. However, the presence of the hysteresis nonlinearity and input saturation problems in this smart material actuators have caused adverse effects on their performance, including reduced operational accuracy and damage to the actuators. To eliminate the negative effects of hysteresis and compensate for input saturation, an adaptive backstepping controller with an anti-windup auxiliary compensation system is developed in this paper. The proposed approach shows good tracking performance for the piezoelectric micro actuating system introducing, which also proves that the anti-windup technology can handle the input saturation effects well.
A robot needs the ability of Simultaneous Localization and Mapping(SLAM) in an unknown environment. It can help the robot navigation and tracking. The traditional method only considers that the robot works in a static...
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The paper considers observability of switched Boolean controlnetworks (SBCNs), for two different observability definitions. First, utilizing the semi-tensor product (STP) method, a coupled system based on the initial...
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ISBN:
(纸本)9781665436601
The paper considers observability of switched Boolean controlnetworks (SBCNs), for two different observability definitions. First, utilizing the semi-tensor product (STP) method, a coupled system based on the initial SBCN is constructed. Then the observability conditions corresponding to diverse definitions are converted into the corresponding set controllability goals for the coupled system. By adopting the set controllability technique of SBCNs, easily verified conditions for observability of SBCNs are obtained. Finally, an example is provided to demonstrate the effectiveness of the proposed results.
Vision-based lane detection (LD) is a key part of autonomous driving technology, and it is also a challenging problem. As one of the important constraints of scene composition, vanishing point (VP) may provide a usefu...
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In this letter, we investigate a robust beamforming problem for localization-aided millimeter wave (mmWave) communication systems. To handle this problem, we propose a novel restriction and relaxation (R&R) method...
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Global localization and kidnapping are two challenging problems in robot localization. The popular method, Monte Carlo Localization (MCL) addresses the problem by iteratively updating a set of particles with a "s...
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