Search Results (32)

The disadvantages of traditional strip fertilization technology for corn planting in China include low fertilizer utilization rates, unstable operation quality, and environmental pollution. Therefore, in this study, a synchronous hole fertilization device for corn planting based on real-time intelligent control is designed, aiming to reduce fertilizer application and increase efficiency through the precise alignment technology of the seed and fertilizer. This device integrates an electric drive precision seeding unit, a slot wheel hole fertilization unit, and a multi-sensor coordinated closed-loop control system. An STM32 single-chip micro-computer is used to dynamically analyze the seed–fertilizer timing signal, and a double closed-loop control strategy (the position loop priority is higher than the speed loop) is used to correct the spatial phase difference between the seed and fertilizer in real time to ensure the precise control of the longitudinal distance (40~70 mm) and the lateral distance (50~80 mm) of the seed and fertilizer. Through the Box–Behnken response surface method, a field multi-factor test was carried out to analyze the mechanism of influence of the implemented forward speed (A), per-hole target fertilizing amount (B), and plant spacing (fertilizer hole interval) (C) on the seed–fertilizer alignment qualification rate (Y₁) and the coefficient of variation in the hole fertilizing amount (Y₂). The results showed that the order of primary and secondary factors affecting Y₁ was A > C > B, and that the order affecting Y₂ was C > B > A; the comprehensive performance of the device was best with the optimal parameter combination of A = 4.2 km/h, B = 4.4 g, and C = 30 cm, with Y₁ as high as 94.024 ± 0.694% and Y₂ as low as 3.147 ± 0.058%, which is significantly better than the traditional strip application method. The device realizes the precise regulation of 2~6 g/hole by optimizing the structural parameters of the outer groove wheel (arc center distance of 25 mm, cross-sectional area of 201.02 mm², effective filling length of 2.73~8.19 mm), which can meet the differentiated agronomic needs of ordinary corn, silage corn, and popcorn. Field verification shows that the device significantly improves the spatial distribution of the concentration of fertilizer, effectively reduces the amount of fertilizer applied, and improves operational stability and reliability in multiple environments. This provides technical support for the regional application of precision agricultural equipment. Full article

With the aging population and rising demand for assistive devices, electric wheelchairs have garnered significant attention. However, existing stair-climbing wheelchairs often suffer from complex structural complexity and limited flexibility. Spoke-wheel mechanisms, known for their simple structure and strong obstacle-crossing capabilities, hold promise but experience oscillation on flat terrain. This paper proposes an improved spoke-wheel mechanism (Flexwheel), which integrates springs into the spokes. These springs compress to varying lengths under gravitational force during ground contact, while sliding grooves and pre-compression constraints regulate spoke length, ensuring a stable height. A novel selection method for the optimal spring constant is developed based on mass, spoke length, and the number of spokes. This mathematical framework is applicable to stable, smooth ground motion under varying friction conditions between the upper and lower spokes. A wheelchair prototype equipped with four Flexwheels, a self-balancing mechanism, and multi-sensor fusion technology is designed. The simulation results indicate that Flexwheel reduces the range in body height from 10.75 mm (traditional spoke wheels) to 3.39 mm on flat terrain, a 68.47% improvement. During stair climbing, Flexwheel significantly reduces body oscillation compared to traditional spoke or circular wheels. Physical experiments validate that Flexwheel exhibits a 6.28 mm height fluctuation vs. traditional spokes wheels’ 12.13 mm, a 48.28% improvement, demonstrating its effectiveness in enhancing wheelchair stability and adaptability. Full article

This study designed and investigated a solid particle spreader, as well as parameter optimization and experimental for a groove wheel, to mitigate the problems of low uniformity and poor control accuracy of solid particulate material UAV spreading. The discrete element method was used to simulate and analyze the displacement range and stability of each grooved wheel at low speeds. Furthermore, orthogonal regression and response surface analyses were used to analyze the influence of each factor on the stability of the discharge rate and pulsation amplitude. The results showed that the helix angle, sharpness, and length of the groove significantly influenced the application performance, whereas the number of grooves had no significant influence. The groove shape was eccentric, the helix angle was 50°, the length was 35 mm, and the number of grooves was 7. Additionally, the bench test results showed that in the range of 10–60 rpm, the relative deviation of the discharging rate between the simulation and bench test is from 0.47% to 10.39%, and the average relative deviation is 3.93%. Between the groove wheel rotation speed and discharge rate, R² was 0.991, and the adjustable range of the discharge amount was between 3.68 and 23.43 g/s. The minimum and maximum variation coefficients of the average discharge rate among individual applicators were 1.01% and 2.79%, respectively, whereas the standard deviations were 0.09 and 0.46 g/s, respectively. In conclusion, the discharge stability and adjustable range of the spreader using the optimized groove wheel satisfied the requirements for solid particulate material discharge. Full article

The pneumatic centralized fertilizer discharge system is an important part of pneumatic fertilization machinery and mainly includes a fertilizer discharge device, an air–fertilizer mixing device and a pneumatic distribution device. In this paper, the mechanical structure, key parameters and research methods of pneumatic centralized discharge devices, air–fertilizer mixing devices and pneumatic distribution devices at home and abroad are briefly analyzed. The advantages and disadvantages of these existing devices are summarized, the existing problems are discussed and improvement methods are put forward. In this paper, the structural adaptability, uniformity and stability of the fertilizer discharge of different types of fertilizer discharge devices, such as external groove wheel types, spiral types and centrifugal types, are comprehensively analyzed. The working principle of air–fertilizer mixing devices using the Venturi effect to achieve the uniform mixing of fertilizer and airflow is expounded. The effects of air–fertilizer mixing devices with different structural forms and parameters on mixing performance and the motion characteristics of air–solid two-phase flows are analyzed. The influence of the internal structure, key parameters and distribution mode of pneumatic distribution devices on the uniformity and accuracy of fertilizer distribution are analyzed. This paper focuses on how to improve the uniformity, stability and consistency of discharge across rows provided by the pneumatic centralized fertilizer discharge system. The research status and progress made regarding the core components of the pneumatic centralized fertilizer discharge system at home and abroad are summarized. Based on different research results, the key factors and methods for improving the uniformity of fertilizer discharge are discussed. Full article

As a key component of fertilization equipment, the fertilizer discharger has an important impact on the accuracy of the amount of fertilizer applied during the fertilization process. Countries around the world have been advocating for reducing the use of chemical fertilizers and improving fertilizer utilization, and researchers have also conducted in-depth research on precision fertilizer devices. In order to further improve the precision of dosing and distribution devices for fertilizers, in this study, four types of fertilizer dischargers (spiral fertilizer dischargers, groove wheel fertilizer dischargers, disc fertilizer dischargers, and air-feed fertilizer dischargers) which are currently commonly used are thoroughly analyzed. The operating principle and performance characteristics of the fertilizer dischargers are elaborated upon, and the current research status of their structure and working parameter optimization are discussed and summarized. Overall, the research of Chinese researchers is mainly described. The problems existing in research on the precise fertilizer discharge of fertilizer dischargers are pointed out, and the future development trend is predicted, aiming to provide a beneficial reference for improving the technical level of precise fertilizer discharge. Full article

At present, numerous wall-climbing robots have been developed, and applied in ship manufacturing for weld detection to ensure safe navigation. Limited by rigid mechanical structure and complex detection, mostly existing robots are hardly to complete weld detection by using fluorescent magnetic particles. Based on permanent magnet adsorption, a wheeled wall-climbing robot is developed to realize the stable adsorption and flexible movement on ship wall. A detection mechanism is designed using a series and parallel flexible adaptation structure to keep cross yokes and detection area close for effective detection. A unified mechanical model is established by analyzing the angle between robot attitude and gravity, to solve safe adsorption and flexible movement for different detection conditions. Integrated the multisensor information and collaboration between control component, an automatic detection control workflow conforms to the standard process is proposed. Experiments show that the robot can move on curvature wall flexibly and stably, complete the weld detection with the standard process, and clearly display the shape and depth of the small defects (groove depth ≥ 30 μm) in standard specimen. Full article

Ni60-WC coatings with different WC contents on the bucket tooth substrates were pre- pared using laser cladding technology. Their abrasive wear properties were assessed using the dry sand rubber wheel test system. The substrate and the hard-facing layer were tested for comparison. The results showed that the hardness of the Ni60-WC coatings increased with the increase in WC content. The wear resistance of the bucket tooth substrate was greatly improved by hard-facing and laser cladding Ni60-WC coatings. The wear rate of the hard-facing layer was reduced to 1/6 of that of the tooth substrate. The wear rate of the laser cladding coatings with 20–40 wt.% WC was similar to that of the hard-facing layer. It is worth mentioning that the wear rate of the coatings with 60–80 wt.% WC was only 1/4 of that of the hard-facing layer. Micro-cutting with surface plastic deformation was the main wear mechanism of the substrate to form narrow and deep furrows. The wear mechanism of the hard-facing layer was mainly plastic deformation with a wide groove, and the surface cracks promoted the removal of the material. The removal of the binder phase caused by micro-cutting was the main wear mechanism of the laser cladding Ni60-WC coatings. However, the hard phase of WC hinders micro-cutting and plastic deformation, which improves the wear resistance of the coating. Full article

To improve the utilization rate of maize seed fertilizer, this study aimed to propose a precise co-sowing control system for the real-time control of the relative position of seed fertilizer during the co-sowing operation. According to the operating speed of the machine, the longitudinal distance between the seed feeder and the outer groove wheel, the height of the seed and fertilizer falling, and the relative position of the seed and fertilizer falling into the soil, the calculation method for the seed and fertilizer falling into the soil was obtained, the precise co-seeding model of the seed fertilizer was constructed, the control algorithm of the precise co-seeding of the seed fertilizer was designed, and the hardware system and software system were designed. Based on the hardware structure and working principle of the motor drive seeding and fertilization control system, a functional circuit based on the STM32F103ZET6 single-chip microcomputer (Zhengdianyuanzi (Guangzhou) Technology Co., Ltd., Guangzhou, China) was built. When the system is working, the satellite speed measurement module collects the operating speed of the machine, the encoder feeds back the motor speed in real time, a Hall sensor detects the time interval between fertilizer and seed discharge at the point of discharge, and the PID algorithm is applied to make the speed regulation system regulate the motor speed and position and adjust the speed and position of the seed discharge tray and fertilizer on the outer slot wheel in real time. The relative position of seed and fertilizer in the soil can be controlled accurately in the process of sowing fertilizer. The test results showed that when the feed speed was 2, 3, and 4 km·h⁻¹, and the grain spacing was 20, 25, and 30 cm, respectively, the seed fertilizer alignment was better and met the requirements of precise sowing, improving fertilizer utilization rate. Full article

DNA requires hydration to maintain its structural integrity. Crystallographic analyses have enabled patterns of water arrangements to be visualized. We survey these water motifs in this review, focusing on left- and right-handed duplex and quadruplex DNAs, together with the i-motif. Common patterns of linear spines of water organization in grooves have been identified and are widely prevalent in right-handed duplexes and quadruplexes. By contrast, a left-handed quadruplex has a distinctive wheel of hydration populating the almost completely circular single groove in this structure. Full article

The grooved-wheel fertilizer machine is one of the most widely used pieces of fertilization equipment. However, detailed information on the fertilizer filling status and the mechanism of particle interactions during the operation of the grooved wheel remains limited. To delve into the underlying mechanisms through which working parameters affect fertilization performance, this study, building upon prior research, conducted a qualitative analysis and numerical investigation of fertilizer particles using the Discrete Element Method. The analysis examined the impact of three working parameters, namely the grooved-wheel speed, working length, and forward speed of the fertilization equipment, on the morphology, forces, and kinetic properties of the fertilizer particles. Combining this analysis with orthogonal experimental research, we optimized the aforementioned working parameters. Both simulation and benchtop experimental results indicate that the grooved-wheel speed and working length influence the fertilizer filling status, while the forward speed of the equipment has no effect on the filling status. The connection between fertilizer force and kinetic changes is influenced by particle-free space. The lowest coefficient of variation (CV) for fertilization uniformity was observed at the grooved-wheel speed of 53.64 r/min, the wheel working length of 33.45 mm, and the forward speed of 0.7–1 m/s. The research findings contribute to a better understanding of the influencing mechanism of particle movement and fertilization outcomes in the operation of grooved-wheel fertilizer spreaders. This understanding enables precise control of the fertilizer application process, facilitating accurate and efficient fertilization. As a result, it enhances fertilizer utilization rates and reduces agricultural costs. Full article

Longitudinal-torsional composite ultrasonic vibration has been widely used in grinding. This paper aims to solve the problem that the resonance frequency deviates greatly from the theoretical design frequency and the vibration mode is poor when the horn is matched with a larger tool head. This paper presents how the longitudinal-torsional composite ultrasonic conical transition horn was designed and optimized by the transfer matrix theory and finite element simulation. For this purpose, the spiral groove parameters were optimized and selected by finite element simulation. Then, the modal analysis and transient dynamic analysis of the horn with grinding wheel were carried out to verify the correctness of the theoretical calculation. The impedance analysis and amplitude test of the horn with grinding wheel were carried out. The test results were in very good agreement with the theoretical and simulation results. Finally, the grinding experiment was carried out. The surface roughness of the workpiece in longitudinal-torsional ultrasonic vibration grinding was obviously reduced compared to that of ordinary grinding. All these obtained results demonstrate that the designed longitudinal-torsional composite ultrasonic horn has very good operational performance for practical applications. Full article

This article focuses on the low accuracy, poor stability, and other shortcomings of the traditional outer-groove buckwheat seed-metering wheel. A wheel-type large-ridge double-row seed-metering device with inner seed-filling holes was designed. The seed-metering device’s structural composition, working principle, and main technical parameters are clarified. The structural parameters of the seed-metering device shell and the seed-metering wheel are determined based on the force analysis, movement trajectory, and physical characteristics of the buckwheat grains. This experiment uses the JPS-12 metering device performance experiment bench for bench experimenting. The experiment uses the seed-metering device’s rotation speed, the seed position’s height, and the seed wheel’s aperture as experiment factors. Based on the experiment indicators of the qualified rate of number of holes and the grain damage rate, we used Design-Expert12 software to design single-factor, response surface, and verification experiments. The experiment results show that the best parameter combination is a seed-metering device rotation speed of 67 r/min, a seed position height of 115 mm, and a seed wheel aperture of 8 mm. In the optimal parameters, the qualified rate of the number of holes is 90.23%, and the grain damage rate is 0.62%. The experiment indicators meet the operational requirements of the buckwheat seeding device. The design and experimenting of the buckwheat large-ridge double-row seeding device provide a reference for further research on buckwheat seeding. Full article

Pre-sowing treatment of seeds by plasma can improve seed vigor and promote seed germination and growth. To solve the problems of low processing volume and uneven treatment in plasma seed treatment devices, according to the process scheme of medium-blocking discharge plasma seed treatment, a medium-blocking discharge vibration-uniform material plasma seed treatment device was designed, the structure and working principle of the vibration-uniform material device were systematically analyzed, and the mathematical model of seed force was established. According to electromagnetic vibration theory, the seed sorting and conveying principles were analyzed in the lower trough, and the relevant parameters were selected and calculated. Using EDEM discrete element simulation software, a numerical simulation of alfalfa seed feeding and vibration-uniform material process was carried out. A three-factor, three-level orthogonal test was established. The results showed that the vibration amplitude and groove shape significantly affected the coefficient of variation of seed uniformity on the groove during the seed feeding and vibration-uniform material processes, and the groove wheel speed had a certain effect on the coefficient of variation of uniformity. The main order of factors affecting the uniformity of seed spreading was vibration amplitude B > notch shape C > speed A. The optimal speed was 35 r/min, the optimal notch shape was circular, and the optimal vibration amplitude was 0.55 mm. Full article

Carbon fiber reinforced plastic (CFRP) is used in various industries because of its high specific strength, but it is well known as a difficult material to cut. In this study, we developed a disc-shaped electrodeposited diamond wire mesh grinding wheel as a new method for cutoff and grooving with a large aspect ratio for CFRP. We confirmed that this tool could be used for machining at a feed rate of 1000 mm/min, equivalent to that of an abrasive waterjet. This tool discharges generated chips through the spaces in the wire mesh, preventing clogging and thereby enabling the suppression of machining temperature. No burrs or delamination were observed on the surface machined with the wire mesh grinding wheel, and the surface roughness was Ra = 2.76 µm. However, the groove width was larger than the wheel thickness due to the runout of the wheel. Additionally, the moderate elasticity and durability of the tool suggest that it might extend tool life by avoiding the crushing of abrasive grains. Full article

The traditional gauge wheel has poor performance in reducing the adhesion to soil and constructing seed furrow, which results in lower seeding quality of the planter. To reduce the adhesion of the gauge wheel to the soil and build a well-structured seed furrow, an elastic gauge wheel with soil retention groove and irregular cavity was designed in this study. The soil retention groove built ridges on both sides of the seed furrow and avoided the gauge wheel compacting the seed furrow sidewalls. The irregular cavity increased the elasticity of the gauge wheel and allowed the wheel to squeeze the soil on both sides of the seed furrow, which reduced the soil adhesion of the wheel and built stable ridges. Soil moisture content was chosen as the experimental factor for comparative tests to evaluate the soil adhesion and the constructed seed furrow of the gauge wheel with an irregular cavity and the traditional gauge wheel. The experimental results showed that the viscosity reduction rate of the gauge wheel with the irregular cavity was not less than 12.61%. Compared with the traditional gauge wheel, the seed furrow constructed by the irregular cavity gauge wheel had ridges on both sides and less backfill soil, and the soil compaction of sidewalls decreased by 18.16%. The field experiment was designed using the Box–Behnken design. The working speed, downforce, and planting depth were taken as experimental factors, and the soil adhesion of the gauge wheel and the consistency of planting depth were taken as evaluation indicators. The optimal operating parameters of planter obtained by Design-Expert 8.0.6 software were as follows: the working speed was 8 km·h⁻¹, the downforce was 844 N, and the planting depth was 65 mm. The verification test of the optimal operating parameters showed that the soil adhesion mass of the gauge wheel was 123.65 g and the coefficient of variation of the planting depth was 5.35%. This study provides a reference for the mechanized construction method of seed furrow by precision planter and the structural design and performance optimization of gauge wheels. Full article