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Chang’e-4 lunar rover is the first achievement of human exploration on the far side of the moon. New working environment brings challenges to the dormancy and wake-up of the lunar rover. The dormancy and wake-up constraints of the lunar rover are analyzed, including energy, thermal control, etc. Then combined with the complex terrain and relay communication, a dormancy and wake-up control strategy is designed for the lunar rover. The strategy includes skyline recognition, dormancy and wake-up time calculation, rover expected attitude calculation, sleeping position planning and moving, sleeping setting, wake-up setting and so on. Finally, the effectiveness of the control strategy is verified by the real on-orbit status.

Photodetectors based on graphene attracted widespread attention because of their superior properties. We have evaluated the low-frequency noise of a graphene-based X-ray detector manufactured from graphene oxide (GO) through a laser process. The low-frequency noise's temperature dependence indicates a nonuniform energy distribution of traps in the device due to a distribution of defects and impurities, most likely due to O-vacancies and hydrogen.

China's first Mars rover Zhurong has successfully began its exploration on Mars surface. It is important to estimate the rover slip while driving on the Mars, for the slip has a negative impact on the navigation accuracy and passing safety. In this paper, we establish the slip estimation model by BP and GA-BP algorithm for Zhurong rover. Pitch and roll of the rover, average current and velocity of the wheel drive motors are selected as input features to train the model. All data are obtained by Zhurong validator's indoor slip experiment. The results demonstrate that genetic algorithm effectively optimizes the weights and thresholds of the BP network, so that GA-BP performs better than the BP neural network in rover slip estimation. The GA-BP model established in this paper has reference value for the slip estimation of Zhurong rover.

China's Zhurong rover successfully reached the Mars surface and began its exploration on May 22nd, 2021. As of June 15, the cumulative driving distance exceeded 100m. The rover will slop when it is driving on the Martian surface, which will affect the accuracy of scientific detection. In view of this phenomenon, an adaptive fuzzy control method based on slip compensation is proposed. The kinematics equation of the Zhurong rover in the process of curvature driving is established, and an adaptive fuzzy controller is designed to compensate the steering radius and driving time of the wheels in the slip process. The simulation results show that the method based on adaptive fuzzy control can compensate the deviation of the rover on the Mars surface. It effectively tracks the ground planning trajectory and has better tracking and security. Finally, the effectiveness of the controller is verified by on-orbit application.

An innovative approach to high-sensitivity simultaneous intensity and direction measurement in a two-channel tapered sensor is proposed and demonstrated. The sensor is comprised of magnetic fluid (MF)- filled micro-capillary and two accompanying micro-fiber, thus enabling evanescent interaction to take place between the optical mode in the capillary and MF. Given the magnetic nanoparticles (MNPs) of MF manifest anisotropic magnetic field. Experimental and numerical simulations were performed simultaneously, which provided a better understanding of the interaction between light and MF in addition to clarifying the dynamic process of MNPs within MF with the assistance of varying magnetic field. The experimental results are well consistent with the numerical simulation results and show that the sensitivity of this sensor reaches up to 244 pm/mT, with the direction error being merely ±1.4°. Therefore, the proposed sensor exhibits a unique sensitivity for the measurement of magnetic field intensity and direction in 3D space, which makes it best suitable for applications in transportation, medicine, and smart device.

According to the idea of "Emerging Engineering Education" talent training model of Ministry of Education, students should be trained to have "metaphysical" concept, connection, imagination, macro thinking. Project-driven experiment teaching focuses on a project, and the goal is the completion of the project; the student is the center of teaching activities, which is supported by the inquiry process. This study analyzes the significance of the project-driven method in experimental teaching. This paper describes the implementation process of experimental teaching in the field of energy and power engineering in terms of project design, teaching system construction and so on under the project-driven method. By analyzing the results of a questionnaire survey distributed to students of energy and power in the College of Mechanical Engineering at the Tianjin University of Technology, it is found that the students are satisfied with the effects of project-driven experimental teaching, and the use of experimental teaching has greatly aroused the students’ enthusiasm for learning. The ability of the students to engage in autonomous learning, engineering practice and innovation has been greatly improved, and a good teaching effect has been achieved.

Flexible ultraviolet (UV) photodetectors based on Ga-doped and Fe-doped ZnO Nanorods (NRs) were successfully fabricated respectively on mica substrate with superior transparency. In this work, Zn 0.987 Ga 0.013 O NRs and Zn 0.984 Feo. 016 O NRs were synthesized using a simple and low-cost hydrothermal method. Meanwhile, the effects of doping elements on the morphology, structure and photoelectric properties of ZnO NRs were systematically studied. The doping of Ga element enhances the UV responsivity of the device reaching 71.44 A/W. While the doping of Fe element is favorable to increase the response speed by 3 times and reduce the dark current to 10−10 A. After 100 cycles of bending, the photodetection performance of the device remains almost unchanged, which indicates the device has a good potential for wearable applications.

Graphene-based photodetectors have received widespread attention because of the superior characteristics. However, most of previous research focused on improving the performance of the detector. Herein, an angle-sensitive photodetector, which fabricated via vertically standing layered graphene (VSG) grown on $\mathrm{n}$ -type silicon substrate, is demonstrated. Due to the vertical structure of the VSG, the current change rate can reach up to 188.6% when the incident angle is 55 degree, which demonstrates promising applications for omnidirectional detection.

Recently, soft electrothermal actuators have attracted tremendous attentions. Large deformation under low driving voltage has long been the design concerns for scholars. However, in practice, apart from larger deformation, higher requirements are put forward for higher deformation speed in repeated cycles to achieve efficient and agile actuation. Herein, a soft electrothermal actuator is fabricated based on laser reduced graphene oxide and silver nanowire composite with polydimethylsiloxane substrate, which completely realizes the above required advantages. Besides, a concept of periodic curvature rate is proposed to accurately evaluate the deformation speed, which is more normalized than time alone to reflect before. The soft electrothermal actuator here can achieve a large curvature of 2.5 cm-1 with a high periodic curvature rate of up to 8.93×10-2 cm-1/s under low power density input of 0.8W•cm-2 (driving voltage of 28V), which shows obvious advantages in both deformation quantity and speed compared with most reported electrothermal actuators till now. Finally, a bionic hand consisting of five U-shaped electrothermal actuators is demonstrated to achieve gesture following and restoring, showing its promising prospects in the emerging bionics field.

Graphene is an excellent two-dimensional (2D) material and can be deployed as sound emitters based on electrical thermoacoustic effect (ETA). Traditional graphene-based ETA emitter renders ineffective audio quality in low frequency range due to its small output magnitude and large total harmonic distortion. Here we propose a packaging method that boosts its low frequency output magnitude from 58 dB to 70 dB at 5 kHz as well as a fully digital operation that eliminates its major source of distortion down to 2.29%. Besides, a Bluetooth module is applied to extend the application of graphene in wireless communication field. Our work shows the great potential of using wireless graphene earphone for practical applications.

Artificial intelligence (AI) shows powerful applications. Most of previous AI devices and systems were focused on electronic devices with pure electrical input to realize pattern recognition or language recognition. However, human can receive many other kinds of information (such as mechanical input). The research of AI with mechanical input remains elusive. Human muscle has the most important function with intelligence: dynamic training process that muscle lines can be broken first and recover to be stronger after exercise. Here, we show a graphene artificial muscle with mechanical intelligence. Multiple muscle lines can be directly printed on flexible substrate. After long run of training process, it shows three stages: decrement, enhancement and stabilized. Moreover, single artificial muscle line is built with laser-scribed graphene and shows “injured” muscle line in the first 1200 s and then start to “recover” after that. A new concept called “Force Learning” is also investigated in this work with accuracy reaching ~96%. Our work shows the great potential of building artificial muscle lines by laser-scribed graphene with the learning ability, which can offer widely applications in robot control, mechanical neuromorphic engineering.

As the demand for display quality increases, flexible and color-tunable light sources attract great attention. Conventional solid-state light-emitting devices mainly produce specific colors via bandgap engineering. This work proposes a flexible, ultra-wide range and tunable spectrum light-emitting device based on laser-induced graphene. The range of spectrum is 650–1000 nm, and its center wavelength can alter from 740 to 950 nm. The device has excellent color quality, good uniformity, and programmable shape. This flexible lighting device has outstanding luminous performance and shows great potential in flexible display.

Coupling coil is considered as the core link of the wireless power transmission system, and the optimal design of coupling coil the has a direct impact on the transmission efficiency and power of the whole wireless power transmission system. In this paper, we utilized ADS software to build a typical wireless power circuit based on the equivalent circuit model of the prototype system to simulate the energy transfer process and analyze the system transmission efficiency and power output which reduced the computational complexity and simplified the coil design process. In order to implement the optimized coupling coil of the wireless transmission system, coupling coil parameters are calculated to the determine the optimal resonant capacitance compensation, coupling coefficient, and radius of coil by the establishment of simulation model of circuit. The equivalent circuit model of the system has the wide applicability. The simulation results show that the design method can improve the transmission performance optimization of the magnetically coupled resonant wireless power transmission system.

With the increasing number of new energy vehicles, the occurrence of new energy vehicle safety accidents is also increasing, and the safety of new energy vehicles has received widespread attention from the government, scholars and society. How to construct a scientific assessment of new energy vehicle safety assessment system and analyze the main factors affecting the safety of new energy vehicles is the focus of this paper. In this paper, a multi-index evaluation matrix is established based on the Analytic Hierarchy Process (AHP), and it is calculated by the numerical analysis software MATLAB. According to the calculation results, the main influencing factors affecting the safety of new energy vehicles are obtained.

Surface acoustic wave (SAW) optical sensor based on two-dimensional (2D) sensing layer can always provide extremely high sensitivity. As an attractive option, the application of exfoliated 2D perovskite on acousto-optic coupling optical sensor is investigated. In this work, exfoliated 2D (PEA) 2 PbI 4 sheet was transferred as a sensing layer onto the delay area of a dual-port SAW resonator with resonant frequency ~497 MHz. From the response under 532 nm laser with intensity of 0.9 mW/cm2, a largest frequency shift of ~13.92 MHz was observed. The ultrahigh sensitivity up to 31.6 ppm/(μW/cm2) was calculated by experiment results. We also carried out theoretical analysis and finite element simulation of 3D model to demonstrate the mechanism and validity for optical sensing. The fabricated optical sensor expressed great potential for a variety of optical applications.

In order to solve the accuracy and delay problems in the traditional flow speed estimation method in the sewage pipe network system, we develop a kind of multi-sensor fusion estimation method. Autoregressive moving average model is used in the estimation process, 3 kinds of fusion method is compared. An example is presented to verify the algorithm, Matlab is used to caculate, and some pictures to explain our points.