Automatic Seedling Research Articles

Separating collected seedlings using subdivided air streams

Large-scale seedling production aims to improve their production capacity and competitiveness by improving productivity, reducing labour costs, and eliminating labour-intensive production processes. With the pursuit of continuously improving productivity, the development of automatic seedling production has become a key technology. However, achieving the automatic separation of rootless collected seedlings into individual plants remains an important challenge because tender rootless seedlings need to be separated into individuals for feeding into seedling production equipment. In this study, a separator composed of subdivided air streams was developed to separate tender collected seedlings into individuals. The air streams for separation were generated by a jetting nozzle array of subdivided air streams at the base of the separator. By opening and closing different subdivided air stream nozzles, in turn, seedlings became suspended with some seedlings at the edge of the floating mass becoming separated. The separator was tested using aubergine and cucumber seedlings intended for grafting and for anthurium seedlings intended for cuttage transplanting. The results demonstrated that the separator could separate tender collected seedlings into individuals without causing damage. Moreover, the maximum separation rates for the collected seedlings were 11,070, 13,590, and 17,100 plants per hour for the aubergine, cucumber, and anthurium seedlings, respectively.

Effect of Compound Biochar Substrate on the Root Growth of Cucumber Plug Seedlings

Since plug seedling plays a key role in automatic transplanting, this work aimed to explore the effect biochar has on the root growth of plug seedlings. The physicochemical properties tests showed that the addition of biochar in the peats could increase the porosity, pH, and EC values of the substrate, and the substrates treated with 0%, 10%, 20%, and 30% biochar could meet the requirements of seedling raising. The water retention of the substrate was superior with the increase of biochar proportion, and the nitrogen release significantly decreased with the increase of the biochar proportion. Our results demonstrated that the substrate with 10% biochar-treated apparently promoted the growth of seedlings and root systems, even the length of the root-tip cells. However, the substrates with 40% and 50% biochar-treated obviously inhibited the growth of seedlings and root systems. It was noticed that the strength of substrate with appropriate biochar proportion was enhanced, as well. Under the interaction of strong root system and solid substrate, the compressive strength of the substrate with 20% and 10% biochar-treated was much better than others, especially that of 40% and 50% biochar-treated, which efficiently satisfied the requirements of automatic seedling picking. The biochar may have a good application prospect in seedling raising.

Trajectory planning and motion control of full-row seedling pick-up arm

Frequent start-stops of automatic seedling transplanters would lengthen the seedling picking time due to alternating movement of the motor, and cause positioning errors and frequent motor vibrations when starting the machine. To solve these problems and ensure the pick-up continuity of automatic transplanters, in this study the smooth circular arc interpolation algorithm and the least square method for multinomial curve fitting were used to conduct the trajectory planning of automatic transplanter based on the movement of the pick-up arm of the transplanter. Velocity and time curves were fitted in segments to acquire motion control parameters and further tracking control was conducted. The mathematical model of the control system was established using Simulink, and simulation analysis and system debugging test were performed. Experiments show that the trajectory curves obtained by MATLAB’s data processing can realize the continual and smooth motion trajectory of the pick-up arm; stepper motor velocity control can effectively track the planning curve and improve the seedling pick-up efficiency. The pick-up and pushing time of each motion of the planned plug seedling transplanter reduced by 1.0678 s and the start-stop times reduced from 6 to 1, which solved the frequent motor vibrations when starting the machine and improved the stability of the system. In addition, overstep and out-of-step of the motor at the start-stop moment were avoided and displacement error was reduced. Keywords: trajectory planning, motion control, motion trajectory simulation, transplanter, stepper positioning DOI: 10.25165/j.ijabe.20201303.5264 Citation: Ren L, Wang N, Cao W B, Li J Q, Ye X C. Trajectory planning and motion control of full-row seedling pick-up arm. Int J Agric & Biol Eng, 2020; 13(3): 41–51.

Trajectory planning and motion control of full-row seedling pick-up arm

Frequent start-stops of automatic seedling transplanters would lengthen the seedling picking time due to alternating movement of the motor, and cause positioning errors and frequent motor vibrations when starting the machine. To solve these problems and ensure the pick-up continuity of automatic transplanters, in this study the smooth circular arc interpolation algorithm and the least square method for multinomial curve fitting were used to conduct the trajectory planning of automatic transplanter based on the movement of the pick-up arm of the transplanter. Velocity and time curves were fitted in segments to acquire motion control parameters and further tracking control was conducted. The mathematical model of the control system was established using Simulink, and simulation analysis and system debugging test were performed. Experiments show that the trajectory curves obtained by MATLAB’s data processing can realize the continual and smooth motion trajectory of the pick-up arm; stepper motor velocity control can effectively track the planning curve and improve the seedling pick-up efficiency. The pick-up and pushing time of each motion of the planned plug seedling transplanter reduced by 1.0678 s and the start-stop times reduced from 6 to 1, which solved the frequent motor vibrations when starting the machine and improved the stability of the system. In addition, overstep and out-of-step of the motor at the start-stop moment were avoided and displacement error was reduced. Keywords: trajectory planning, motion control, motion trajectory simulation, transplanter, stepper positioning DOI: 10.25165/j.ijabe.20201303.5264 Citation: Ren L, Wang N, Cao W B, Li J Q, Ye X C. Trajectory planning and motion control of full-row seedling pick-up arm. Int J Agric & Biol Eng, 2020; 13(3): 41–51.

Reciprocating Mechanism for Whole Row Automatic Seedling Picking and Dropping on a Transplanter

The pick-up device is the key to develop automatic transplanting, thus a whole row pneumatic seedling pick-up device was developed with reciprocating movement. In order to develop low-damage and high-efficiency seedling picking, six or eight end-effectors were installed in the pick-up device. We planned the required picking-trajectory by polynomial fit, then the consistency of the simulated trajectory and theoretical trajectory were verified. The air cylinder and photoelectric sensor were used to control the reciprocating motion of the end-effector, and the coordinated control scheme of seedling transporting, picking and dropping were designed in detail, then a control program was compiled. The experiment results showed that when the cylinder stroke was 40 mm and the seedling pushing speed was 0.54 m/s, the optimal seedling pushing time should be 0.074 s. The seedling dropping accuracy tests of the cylinder indicated that the average minimum value of ΔS was 0.25 mm when the frequency of seedling picking was 18 plants/claw/min. To ensure the work efficiency and the success ratio of seedling picking, the working parameters were selected as seedling picking frequency at 18 plants/claw/min, water content at 60%, depth at 40 mm and angle at 10°, and the finally success ratio of seedling picking was 98.08%. This indicated that the designed pick-up device could meet the requirements of seedling picking and dropping reciprocating movement under the operation of the optimized control system, which is of a great significance to the development of automatic transplanter technology.

Development of a generator-powered self-propelled automatic tray loading/unloading machine for use in rice nurseries

The objective of this study was to develop a generator-powered self-propelled automatic tray loading/unloading machine for rice seedling nurseries by using a gantry as the transport system to automate seedling tray placement and harvesting. During input operations, seedling trays are transported by conveyor belts to the nursery, and the tray loading/unloading machine automatically places the trays in rows in the nursery. During output operations, the tray loading/unloading machine automatically gathers the seedling trays from the nursery and transports them on conveyor belts to an automatic seedling mat roller. The entire system comprises mechanical components that achieve high operational stability and few malfunctions. Using a programmable logic controller for automation can effectively alleviate the inconvenience of laying heavy power cables. The tray loading/unloading machine automatically moves along the trusses of the gantry transport system, placing seedling trays in rows in the nursery. Alternatively, it can reverse directions and gather seedling trays from the nursery and transport them to the conveyor belts. The tray unloading capacity is 741 trays per hour, and tray loading capacity is 763 trays per hour. The tray loading/unloading machine enhances the automation operation of rice seedling nursery and alleviates the difficulty in hiring workers in farming villages where there are a shortage of labor.

Skewness correction and quality evaluation of plug seedling images based on Canny operator and Hough transform

The acquisition of quality information for plug seedlings is the foundation for automatic seedling transplanting. Machine vision technology is an extensively used method for this task. In the visual inspection of plug seedlings, the skewness of the images of dense-cell seedlings and the accuracy of target extraction affect the quality evaluation of plug seedlings. This study proposed a skewness correction algorithm on the basis of Canny operator and Hough transform for the images of a plug tray to improve the visual inspection method for transplanting equipment. Watershed algorithm was used to segment overlapping leaves, and gravity center method was applied to distinguish transboundary leaves. The leaf area and number of seedling leaves in the images of plug trays were extracted and used for quality evaluation. Two-week-old seedlings of Salvia splendens in 200-cell plug trays in a greenhouse were the objects of this study. Industrial cameras were used to capture images of the plug trays. These images underwent grayscale conversion in 2b–g–r channel, median filtering, Canny contour detection, and Hough transform to complete contour detection and skewness correction. The corrected angle deviation of the trays was less than 0.85°. Pre-treatment with grayscale conversion in 2g–r–b channel, binarization, and watershed algorithms were adopted to extract the target of the seedlings in the images. The image of the plug tray was divided into 200 small square areas in accordance with the cell area. The gravity center of the seedling leaves in the cell was calculated to locate the seedling. The number of the leaves and the area of seedlings in each cell were obtained and used as criteria to discriminate the quality of each seedling. The skewness angle of the plug tray during the actual delivery of plug seedlings was within the range of ±3°. Four sets of plug trays with skewness of ±1°, ±2°, and ±3° were obtained. Subsequently, the quality of seedlings in the four sets of plug trays was identified. The evaluation accuracy in the tray skewness and the angle correction situations were determined. Results showed that the average accuracy of seedling evaluation is 98% after angle correction. In contrast to the uncorrected images, the corrected ones can increase by 1.1–9.4 percentage points, thereby improving the evaluation accuracy for automatic seedling transplanting.

AN ECONOMIC EVALUATION OF THE EFFICIENCY OF OPERATING AGRICULTURAL MACHINES IN PRODUCTION OF WHEAT

AN ECONOMIC EVALUATION OF THE EFFICIENCY OF OPERATING AGRICULTURAL MACHINES IN PRODUCTION OF WHEAT

Development of single row automatic transplanting device for potted vegetable seedlings

In China, low degree of automation seriously affects the working efficiency and quality in vegetable transplanting. As one of the most important vegetables in China even in the world, tomato was taken as the research object in this study. An automatic single-row transplanting device was designed, based on the statistical analysis of the physical and mechanical properties of tomato seedlings of a typical variety. Based on the technology of mechatronics, the device integrated the functions of transporting seedling tray, automatic seedling extraction and mechanical planting. The kinematics orthogonality solution combined with the dynamic sequence solution method was used to optimize and analyze the kinematic parameters of the automatic seeding mechanism, and the “sickle” trajectory was obtained. According to the position and movement requirement for taking and dropping seedling, the mechanical conditions and the working parameters of key execution parts were obtained by using analytic drawing method to analyze the mechanical condition of seedling collecting mechanism. The transplanting experiment was conducted at room temperature of 25°C, and the age and moisture content of the seedlings were 40 d and 55%, respectively. The results showed that the highest success rate was 92.59%, and the lowest rate of leakage was 23.13%, when the transplanting frequency was 60 plants/min. The lowest success rate was 77.78%, and the highest rate of leakage was 38.75%, when transplanting frequency was 120 plants/min. When the transplanting frequency is between 60-90 plants/min, the device can meet the requirement of high speed transplanting for potted vegetable seedling. Keywords: potted vegetable seedling, seedling mechanism, automatic transplanting, tomato seedling, transplanting experiment DOI: 10.25165/j.ijabe.20181103.3969 Citation: Jin X, Li D Y, Ma H, Ji J T, Zhao K X, Pang J. Development of single row automatic transplanting device for potted vegetable seedlings. Int J Agric & Biol Eng, 2018; 11(3): 67–75.

Design and implementation of Intelligent transplanting system based on photoelectric sensor and PLC

Industrial seedling rearing is an important part of seedling transplanting technique. At present, there exists the phenomenon that soil base on the tray may have empty seedling on it, which will lead to a large number of leakage and reduce the yield in the course of automatic transplanting in the field. To solve this problem, automatic seedling identification method is studied to skip picking empty soil bases. An intelligent transplanting system are designed with the use of the picking mechanism five-bar and fixed-axis gear train, the seedling tray conveying mechanism (with transverse and longitudinal seedlings feeding function), the eccentric disk parallel four-bar duck mouthpiece planting mechanism, the electric sensor for seedling detection and identification of the seedling tray, the position sensor, stepper motor and PLC control system. By use of computer logic programming and control, it can be used to identify effectively whether the soil base is empty or not, and to control the automatic transmission of seedling tray. The tray is moved to quickly skip the action path of the manipulator to avoid the picking of empty soil base. The system was tested by using pepper seedlings on indoor condition. The results showed that when the transplanting frequency was 90/min, the rate of success seedling picking was 88.23% and the leakage rate was 16.46%, which could meet the requirement of pepper transplanting. Compared with the transplanting model without seedling identification, the average rate of leakage was reduced about 12%. The research provides a useful reference for the development of intelligent agricultural transplanting technology and equipment.

Seedling Leaf Morphology Measurement Based on Photometric Stereo

In order to achieve the on-line nondestructive assessment for vegetable seedling growth, the method and system for measuring the seedling’s leaf morphology based on photometric stereo vision, was introduced in this paper. Through parsing the image luminance information of the seedling leaves under 4 LED light sources, the discrete normal vectors of leaf’s surface could be determined based on photometric stereo vision. According to the normal vectors’ distribution, the leaf’s space plane was fit. And the leaf’s inclination angle was measured as the angle between the fitting plane and camera imaging plane, thus its actual length and size also could be accurately measured. As the test result shown, compared with the manual measurement, the auto-measurement method in this paper has an average error of 3.71mm for leaf length, and 62.57mm2 for leaf size, which was valuable for developing the automatic seedling monitoring system.

Development of single row automatic transplanting device for potted vegetable seedlings

In China, low degree of automation seriously affects the working efficiency and quality in vegetable transplanting. As one of the most important vegetables in China even in the world, tomato was taken as the research object in this study. An automatic single-row transplanting device was designed, based on the statistical analysis of the physical and mechanical properties of tomato seedlings of a typical variety. Based on the technology of mechatronics, the device integrated the functions of transporting seedling tray, automatic seedling extraction and mechanical planting. The kinematics orthogonality solution combined with the dynamic sequence solution method was used to optimize and analyze the kinematic parameters of the automatic seeding mechanism, and the “sickle” trajectory was obtained. According to the position and movement requirement for taking and dropping seedling, the mechanical conditions and the working parameters of key execution parts were obtained by using analytic drawing method to analyze the mechanical condition of seedling collecting mechanism. The transplanting experiment was conducted at room temperature of 25°C, and the age and moisture content of the seedlings were 40 d and 55%, respectively. The results showed that the highest success rate was 92.59%, and the lowest rate of leakage was 23.13%, when the transplanting frequency was 60 plants/min. The lowest success rate was 77.78%, and the highest rate of leakage was 38.75%, when transplanting frequency was 120 plants/min. When the transplanting frequency is between 60-90 plants/min, the device can meet the requirement of high speed transplanting for potted vegetable seedling. Keywords: potted vegetable seedling, seedling mechanism, automatic transplanting, tomato seedling, transplanting experiment DOI: 10.25165/j.ijabe.20181103.3969 Citation: Jin X, Li D Y, Ma H, Ji J T, Zhao K X, Pang J. Development of single row automatic transplanting device for potted vegetable seedlings. Int J Agric & Biol Eng, 2018; 11(3): 67–75.

A Novel Color Analysis Technique for Differentiation of Mix Grass Cover under Shade and without Shade in Green Infrastructures

Abstract Color analysis was found to be a low-cost and noninvasive technique to distinguish plant and soil, crop and weed, living and dead plant, diseased and healthy leaves, and human and plant in field and automatic seedling transplantation systems. However, color analysis was rarely utilized to differentiate various types of shade by grass cover. The main objective of this study was to quantify and differentiate mix grass cover under shade and light in a green infrastructure. The spatial heterogeneity of mix grass species in the selected site was categorized into three different portions, i.e., (1) mix grass cover under tree shade (MUT); (2) mix grass cover under self-shade (MUS); and (3) mix grass cover without shade (MWS). Field monitoring was conducted for about six months to validate the color analysis technique. A java-based image analysis tool, ImageJ, was used for color analysis. Lab color space was adopted for the present study, which identifies the spatial heterogeneity of mix grass cover based on lightness variation of green color. L describes lightness, and a and b represent the color opponents green–red and blue–yellow. ImageJ categorizes L, a, and b using 256 segments on a scale varying between 0 and 255. The range of L values for MUT, MUS, and MWS were found to lie within 20–91, 92–162, and 162–233, respectively. Ranges of a and b values were found to be 0–134 and 154–255, respectively, for the three categories of mix grass. Proportions of MUT, MUS, and MWS were found to vary within 0.2–3.0 %, 0–53 %, and 12–49 %, respectively. Variation in MUT and MWS proportions was found to be consistent with change in rainfall depth during the dry period. However, MUT and MWS were found to change with respect to shoot growth rate during the wet period. The MUS proportion variation trend was not found to be consistent with rainfall depth or shoot growth during the wet period.

Automated image-processing for counting seedlings in a wheat field

Wheat field seedling density has a significant impact on the yield and quality of grains. Accurate and timely estimates of wheat field seedling density can guide cultivation to ensure high yield. The objective of this study was to develop an image-processing based, automatic counting method for wheat field seedlings, to investigate the principle of automatic counting of wheat emergence in the field, and to validate the newly developed method in various conditions. Digital images of the wheat fields at seedling stages with five cultivars and five seedling densities were acquired directly from above the fields. The wheat seedlings information was extracted from the background using excessive green and Otsu’s method. By analyzing the characteristic parameters of the overlapping regions (Overlapping region is a number of overlapping wheat seedlings in the image) of the fields, a chain code-based skeleton optimization method and corresponding equation were established for automatic counting of wheat seedlings in the overlapping regions. The results showed that the newly developed method can effectively count the number of wheat seedlings, with an average accuracy rate of 89.94 % and a highest accuracy rate of 99.21 %. The results also indicated that the accuracy of counting was not affected by different cultivars. However, the seedling density had significant impact on the counting accuracy (P 92 %) could be obtained. The study demonstrated that the newly developed method is reliable for automatic wheat seedlings counting, and also provides a theoretical perspective for automatic seedling counting in the wheat field.

Motion Analysis for Vegetable Potted Seedling Pick-Up Mechanism with Double Crank Geared Linkages

The semi-automatic feeding mechanism of vegetable transplanter was nacelle basket type which is available with manual feeding for transplanting vegetable potted seedlings. However, the efficiency is lower to meet the needs. To improve it, a new design of the potted seedling pick-up mechanism with double crank geared five-bar linkages model was expounded for automatic seedling picking. The kinematics model of the pick-up mechanism was established by mathematical analysis method. The influence of the structural parameters on the motion trajectory and relative velocity of the seedling pick-up arm cusp was investigated. The design of optimization objective for picking vegetable potted seedling was proposed. Meanwhile, the optimal parameter combination of the pick-up mechanism was obtained by using MATLAB based on the objective. With it, when the seedlings pot were being pulled out, the path of the seedling pick-up arm inserting was straightly and more perpendicular to potted seedling. Furthermore, the velocity of seedling taking and dropping cusps were relatively lower in order to meet the speeds demand of seedling picking up with seedling feeding in automatic way.

Design of an automatic seedling feeder for bare-rooted cotton seedling transplanter and its simulation analysis

In order to feed the seedling automatically and to solve problem of seedling leakage,an automatic seedling feeder which can convey the cotton seedling horizontally and longitudinally according to granville2-ZQ4 type semi automatic bare-rooted cotton seedling transplanter.In addition,a control system for detecting seedling was designed,which accelerate the feeding speed when no seeding was detected,and enable the feeder catch the seedling normally without leaking.The motion simulation analysis showed that the motion trajectory of the designed seedling feeder is "bow" shaped and the interval for sending a seedling is 1.6 s,which could achieve the expected goal and satisfy the requirement of bare-rooted cotton seedling transplanter.

The System of Automatic Seedling Selection by the Early Molecular Diagnosis of Circadian Rhythms

Abstract We have developed the system of automatic seedling selection using an early molecular diagnosis of circadian rhythms. To measure the rhythms of gene expression by bioluminescence with in non-destructive and in real time, we used a measurement system for bioluminescence, called Kondotron. Moreover, to improve the efficiency of seedling selection, a manipulator for automatic seedling selection using the decision for the circadian rhythms in bioluminescence was introduced. Using this manipulator, it became possible to select automatically seedlings in the early stage based on the result of bioluminescent measurement. This system can measure 40 samples simultaneously more than one week in real time. Moreover, it is possible to measure seedlings continuously because new seedlings are supplied to measurement sample holders when they are picked out from the measurement holder. Therefore, it is possible to research in the flexible and wide experiment of gene expression since it can analysis the circadian rhythms under various purposes (automatic selection based on statistical processing, selection by threshold, and so on) and environment (light conditions) by this system.

Research and Design of Automatic Monitoring System for Seedling in Solar Greenhouse

An automatic greenhouse seedling monitoring system that can make use of solar energy as power supply to conduct regular monitoring and collect air temperature, air humidity, soil temperature, soil water demand and other parameters is designed. The collected data will be transmitted wirelessly to the upper PC system of host and then, the PC system will compute and process such large amounts of data timely and automatically and carry out corresponding operations for greenhouse through automatic control of feedback signals. With the large capacity of data acquisition, reliable data transmission, humanistic data processing, easy operation, this system will have great practical use. Through the application of this system, it can greatly reduce labor intensity and improve the level of scientific breeding and thus bringing out high quality seedlings to ensure and improve crop yields. This system is feasible and has certain practical value.

Review on the proceeding of automatic seedlings classification by computer vision

The classification of seedlings is important to ensure the viability of seedlings after transplantation and is acknowledged as a key factor in forestation and environmental improvement. Based on numerous papers on automatic seedling classification (ASC), the seedling grading theory, traditional grading methods, the background and the proceeding of ASC techniques are described. The automation of the measurement of seedling morphological characteristics by photoelectric meters and computer vision is studied, and the automatic methods of the current grading systems are described respectively. And the further researches on ASC by computer vision are proposed.

Grafting Robot

An aging farm population, increase of plant purchases, and a shortage of skilled workers have made it necessary to automate grafting in Japan. Development of a grafting robot targeted efficient mass production of seedlings, especially cucumbers. After surveying current grafting, we designed a device for studying the mechanical functions of grafting based on grafting techniques and mechanical grafting technology. To improve functions, we developed an experimental model and two demonstration models. The grafting robot produced 815 plants/h (about 3 times manual grafting) at a success rate of 97.1%. To further automate the process, we devloped the grafting robot with an automatic seedling feeder. An improved demonstration grafting robot was marketed in 1993.