Key technologies of fully autonomous drilling system for coal mine anti-impact drilling robot

For the technical problem of low intelligence in the process of drilling and pressure relief in high stress mines, the research status of pressure relief technology and equipment at home and abroad is summarized and analyzed in this study. It is pointed out that the development of high-performance, highly reliable, and efficient fully autonomous drilling system of anti-impact drilling robot is an important development direction to solve the problem of rock burst prevention and control. To this end, the five key technologies that affect the performance of the drilling system, namely “the precise recognition of hole position, the precise perception of drilling tool posture, the wireless electromagnetic intelligent detection, the intelligent recognition of drilling tool operation status, and the precise control of the drilling system” have been summarized, and the solutions and methods have been provided. In response to the problem of accurate identification of pressure relief holes in complex and harsh environments, a SinGAN model for pressure relief hole image sample expansion is developed, which integrates image size adjustment and multi-stage training modes. The Faster RCNN optimized by multi-layer feature fusion is introduced, and a hole position recognition model based on an improved SqueezeNet lightweight network architecture is constructed to achieve an accurate and fast recognition of pressure relief hole positions. To address the issue of precise perception of drilling tool posture, the unscented Kalman filter optimized by improved gradient descent algorithm is designed for the initial alignment of Inertial Measurement Unit (IMU). Multiple IMU spatial array layouts are designed, and a BP neural network-based compensation method for drilling tool posture error is studied, aiming to improve the accuracy of drilling tool posture calculation and achieve a precise drilling pressure relief. Aiming at the precise detection of drilling conditions in complex geological environments, a wireless elec-tromagnetic transmission system architecture for underground measurement while drilling in coal mines has been established. The principles of adaptive modulation of weak electromagnetic wave signals and high-speed bidirec-tional electromagnetic transmission technology have been explored, and the measurement principles and imple-mentation processes of geological parameters, geological parameters, and engineering parameters at the bottom of the hole have been investigated. To address the issue of identifying the operational status of drilling systems, a multi-domain feature extraction architecture for drilling signals in the time domain, frequency domain, and time frequency domain, as well as a deep network advanced feature extraction architecture, have been constructed. In addition, the key component health status assessment and fault diagnosis techniques for drilling systems have been proposed, and a prediction model for sticking risk factors based on an improved bat optimized long-term and short-term memory network has been built to accurately predict the stuck status of pressure relief drilling tools. In terms of the issue of precise control of drilling systems, the working principle of the hydraulic system of the drilling system is analyzed, and a precise control scheme for the drilling system considering the characteristics of coal and rock is formulated. The principle of solving the optimal control parameters of the drilling system based on torque and position is explored, aiming to achieve intelligent collaborative control and parallel operation of the drilling return system and feed system

Mapping QTLs for the tissue culture performance of rice mature embryo using indica-japonica recombinant inbred lines

Abstract The tissue culture performance is the determinant factor of genetic transformation in indica rice (Oryza sativa L.). Quantitative trait loci (QTLs) associated with the tissue culture performance of mature embryo were detected by 202 genetic markers and 190 recombinant inbred lines (RILs) derived from the cross between two rice varieties, 93-11 (indica) as female parent and Nipponbare (japonica) as male parent. A composite interval mapping (CIM) was used to identify the QTLs for the tissue culture performance. The tissue culture performance of rice mature embryo were evaluated by six parameters, embryogenic calli induction rate (ECR), callus subculture capability (CSC), plantlet regeneration rate (RR), average number of regenerated shoots per callus (NRS), green plantlet regeneration rate (GRR) and average number of regenerated green shoots per callus (NRGS). Nipponbare has better tissue culture response than 93-11 because all indicators were higher in Nipponbare except CSC. Four QTLs for ECR, five QTLs for CSC, three QTLs for RR, two QTLs for NRS, four QTLs for GRR and three QTLs for NRGS were detected. These putative QTLs associated with tissue culture performance were distributed on eight rice chromosomes. These results demonstrated the possibilities of improving the tissue culture performance of indica rice by marker assisted selection (MAS) with those desirable alleles of japonica rice. Keywords: mature embryo; quantitative trait loci (QTLs); rice; recombinant inbred lines (RILs); tissue culture performance. Abbreviations: CAPS-cleaved amplified polymorphic sequence; CIM-composite interval mapping; CSC-callus subculture capability; DH-doubled haploid; ECR-embryogenic calli induction rate; GRR-green plantlet regeneration rate; LOD-logarithm of odds; MAS-marker assisted selection; NRGS-average number of regenerated green shoots per callus; NRS-average number of regenerated shoots per callus; QTLs-quantitative trait loci; RILs-recombinant inbred lines; RR-plantlet regeneration rate; SSRsimple sequence repeats; STS-sequence-tagged site

Design of Pseudo-Command Restricted Controller for Tailless Unmanned Aerial Vehicles Based on Attainable Moment Set

This work investigates the pseudo-command restricted problem for tailless unmanned aerial vehicles with snake-shaped maneuver flight missions. The main challenge of designing such a pseudo-command restricted controller lies in the fact that the necessity of control allocation means it will be difficult to provide a precise envelope of pseudo-command to the flight controller; designing a compensation system to deal with insufficient capabilities beyond this envelope is another challenge. The envelope of pseudo-command can be expressed by attainable moment sets, which leave some open problems, such as how to obtain the attainable moment sets online and how to reduce the computational complexity of the algorithm, as well as how to ensure independent control allocation and the convexity of attainable moments sets. In this article, an innovative algorithm is proposed for the calculation of attainable moment sets, which can be implemented by fitting wind tunnel data into a function to solve the problems presented above. Furthermore, the algorithm is independent of control allocation and can be obtained online. Moreover, based on the above attainable moment sets algorithm, a flight performance assurance system is designed, which not only guarantees that the command is constrained within the envelope so that its behavior is more predictable, but also supports adaptive compensation for the pseudo-command restricted controller. Finally, the effectiveness of the AMS algorithm and the advantages of the pseudo-command restricted control system are validated through two sets of independent simulations

FF-RRT*: a sampling-improved path planning algorithm for mobile robots against concave cavity obstacle

Abstract The slow convergence rate and large cost of the initial solution limit the performance of rapidly exploring random tree star (RRT*). To address this issue, this paper proposes a modified RRT* algorithm (defined as FF-RRT*) that creates an optimal initial solution with a fast convergence rate. An improved hybrid sampling method is proposed to speed up the convergence rate by decreasing the iterations and overcoming the application limitation of the original hybrid sampling method towards concave cavity obstacle. The improved hybrid sampling method combines the goal bias sampling strategy and random sampling strategy, which requires a few searching time, resulting in a faster convergence rate than the existing method. Then, a parent node is created for the sampling node to optimize the path. Finally, the performance of FF-RRT* is validated in four simulation environments and compared with the other algorithms. The FF-RRT* shortens 32% of the convergence time in complex maze environment and 25% of the convergence time in simple maze environment compared to F-RRT*. And in a complex maze with a concave cavity obstacle, the average convergence time of Fast-RRT* in this environment is 134% more than the complex maze environment compared to 12% with F-RRT* and 34% with FF-RRT*. The simulation results show that FF-RRT* possesses superior performance compared to the other algorithms, and also fits with a much more complex environment

Theaflavin-3,3'-Digallate Protects Liver and Kidney Functions in Diabetic Rats by Up-Regulating Circ-ITCH and Nrf2 Signaling Pathway

Theaflavin-3,3′-digallate (TFDG) in black tea has a strong antioxidant capacity. However, its effect on diabetic liver and kidney injury and the underlying mechanisms remain unclear. In the present study, our findings indicated that TFDG administration effectively lowers the fasting blood glucose and serum lipid concentrations and enhances the functionality and cellular architecture of the liver and kidney in rats with diabetes. The data also showed that TFDG mitigates oxidative harm in the liver and kidney of rats afflicted with diabetes. Additionally, metformin combined with TFDG was significantly more effective in reducing blood glucose and oxidative stress. Further studies suggested that TFDG upregulates the Nrf2 signal pathway and circ-ITCH (hsa_circ_0001141) expression. Silencing of circ-ITCH by transfection of the interfering plasmid apparently reduces the effects of TFDG on the Nrf2 signal pathway and oxidative stress in high-glucose-treated hepatic and renal cells. In conclusion, the present study highlights the great potential of TFDG in ameliorating diabetic liver and kidney injury by up-regulating circ-ITCH to promote the Nrf2 signal pathway and provides a potential option for the prevention and treatment of diabetic complications

Incremental Backstepping Sliding-Mode Trajectory Control for Tailless Aircraft with Stability Enhancer

This paper presents an incremental backstepping sliding-mode (IBS) controller for trajectory control of a tailless aircraft with unknown disturbances and model uncertainties. The proposed controller is based on a nonlinear dynamic model of the tailless aircraft. A stability enhancer (SE) that limits both the rate and amplitude of the virtual control input is proposed. The stability enhancer consists of two layers. When the virtual control input approaches the edge, the first layer SE would be activated to modify the trajectory tracking error; when the virtual control input exceeds the edge, the second layer SE would reduce the control gains to make sure the virtual control input drops within the edge as soon as possible. With the help of SE, the incremental control method could be extended to outer-loop control without considering the dynamics of the inner-loop system. In addition, an adaptive estimator for state derivatives is proposed, together with IBS, allowing the controller to show excellent robustness. Finally, two simulations are presented. The first simulation shows that the system is insensitive to external disturbances and model uncertainties, and the effectiveness of SE is proved in the second simulation

A Multiobjective Incremental Control Allocation Strategy for Tailless Aircraft

To address the control allocation problem caused by the redundant arrangement of control surfaces with nonlinear effectiveness for tailless aircraft, a novel multiobjective incremental control allocation (MICA) strategy is proposed. Firstly, the incremental nonlinear control allocation (INCA) method together with the active set quadratic programming algorithm is adopted to precisely allocate the virtual control commands. Secondly, a series of normalized objective functions in the form of increment are designed. Combining these functions by means of linear weighted sum, an incremental multiobjective function is constructed. Then, an improved nondominated sorting genetic algorithm (INSGA) is introduced to offline determine a set of weights that best meets the requirements of each flight phase. In this way, the dependence on subjective experience is minimized based on the theory of Pareto optimal. Meanwhile, the huge computational burden that the intelligent optimization algorithm brings can also be avoided. Finally, combined with the nonlinear dynamic inversion (NDI) control method, a closed-loop validation for the effectiveness of this control allocation strategy is carried out on the tailless aircraft model

New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry