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Path planning is a critical aspect of the harvesting process for unmanned combine harvesters, and the headland turning paths play a crucial role in connecting two parallel paths. However, previous studies have often simplified the combine harvester as a mass point, leading to suboptimal or meaningless planned paths. In this paper, a simplified geometrical model for a tracked combine harvester that considers the influence of the header and tracks on headland turning was developed. Using this model, new calculation formulae for path length, turning time, and headland width for four commonly used headland turning types: fishtail turn, bulb turn, semicircle turn, and u turn were deduced and deeply analysed. The results revealed that the semicircle turn achieved the greatest reduction in path length, turning time, and headland width, reaching up to 79.0%, 74.0%, and 36.1%, respectively, if the harvester turned to the left. To ensure sufficient turning area for unmanned harvesting, the field periphery should be cut at least twice for u turns, three times for semicircle turns, three to four times for fishtail turns, and three to five times for bulb turns. It is suggested that the semicircle turn is the preferred option for most situations, and the harvester should switch between the semicircle turn and the u turn in special cases if it has a differential steering function. This approach can significantly improve working efficiency and always determine the minimum required headland width. • A new simplified model for tracked combine harvester is developed. • New formulas of path length, turning time and headland turning width are deduced. • Four common turning types' performances are analysed thoroughly. • Guidance and advice are concluded for better path planning. [ABSTRACT FROM AUTHOR]

As labour requirements in horticultural become more challenging, automated solutions are becoming an effective approach to maintain productivity and quality. This paper presents the design and performance evaluation of a novel multi-arm kiwifruit harvesting robot designed to operate autonomously in pergola style orchards. The harvester consists of four robotic arms that have been designed specifically for kiwifruit harvesting, each with a novel end-effector developed to enable safe harvesting of the kiwifruit. The vision system leverages recent advances in deep neural networks and stereo matching for reliably detecting and locating kiwifruit in real-world lighting conditions. Furthermore, a novel dynamic fruit scheduling system is presented that has been developed to coordinate the four arms throughout the harvesting process. The performance of the harvester has been measured through a comprehensive and realistic field-trial in a commercial orchard environment. The results show that the presented harvester is capable of successfully harvesting 51.0% of the total number of kiwifruit within the orchard with an average cycle time of 5.5s/fruit. • This paper has reported the design and performance of a novel robotic kiwifruit harvesting system. • Detection rate of 89.6% of reachable kiwifruit with a deep network based vision system. • Measurement of its in-orchard performance shows that it is capable of picking 51.0% of kiwifruit in the three test orchards. • It is estimated that with further development the unit may be capable of harvesting 70% of the kiwifruit [ABSTRACT FROM AUTHOR]

Current harvesting robots have limited performance, due to the unstructured and dynamic nature of both the target crops and their environment. Efforts to date focus on improving sensing and robotic systems. This paper presents a parallel approach, to 'design' the crop and its environment to best fit the robot, similar to robotic integration in industrial robot deployments. A systematic methodology to select and modify the crop 'design' (crop and environment) to improve robotic harvesting is presented. We define crop-dependent robotic features for successful harvesting (e.g., visibility, reachability), from which associated crop features are identified (e.g., crop density, internode length). Methods to influence the crop features are derived (e.g., cultivation practices, climate control) along with a methodological approach to evaluate the proposed designs. A case study of crop 'design' for robotic sweet pepper harvesting is presented, with statistical analyses of influential parameters. Since comparison of the multitude of existing crops and possible modifications is impossible due to complexity and time limitations, a sequential field experimental setup is planned. Experiments over three years, 10 cultivars, two climate control conditions, two cultivation techniques and two artificial illumination types were performed. Results showed how modifying the crop effects the crops characteristics influencing robotic harvesting by increased visibility and reachability. The systematic crop 'design' approach also led to robot design recommendations. The presented 'engineering' the crop 'design' framework highlights the importance of close synergy between crop and robot design achieved by strong collaboration between robotic and agronomy experts resulting in improved robotic harvesting performance. • Systems engineering framework for crop design for robotic harvesting. • Methodologies of crop selection & modification to influence crop-dependent features. • Design of best fit crop for robotic harvesting. • Case study of crop 'design' (selection & modification) for robotic pepper harvester. [ABSTRACT FROM AUTHOR]

One of the most challenging aspects of the development, at the Institute of Agricultural and Environmental Engineering (IMAG B.V.), of an automatic harvesting machine for cucumbers was to achieve a fast and accurate eye–hand co-ordination during the picking operation. This paper presents a procedure developed for the cucumber harvesting robot to pursue this objective. The procedure contains two main components. First of all acquisition of sensory information about the working environment of the robot and, secondly, a program to generate collision-free manipulator motions to direct the end-effector to and from the cucumber. This paper elaborates on the latter. Collision-free manipulator motions were generated with a so-called path search algorithm. In this research the A*-search algorithm was used. With some numerical examples the search procedure is illustrated and analysed in view of application to cucumber harvesting. It is concluded that collision-free motions can be calculated for the seven degrees-of-freedom manipulator used in the cucumber picking device. The A*-search algorithm is easy to implement and robust. This algorithm either produces a solution or stops when a solution cannot be found. This favourable property, however, makes the algorithm prohibitively slow. The results showed that the algorithm does not include much intelligence in the search procedure. It is concluded that to meet the required 10 s for a single harvest cycle, further research is needed to find fast algorithms that produce solutions using as much information about the particular structure of the problem as possible and give a clear message if such a solution can not be found. [Copyright &y& Elsevier]

The objective of this paper was to describe and demonstrate a novel quarter milking analysis device (Mi4) for use in the field of bovine milking research. The Mi4 was developed for investigating the effects of milking machine factors such as vacuum level, pulsation settings and liner characteristics on milk flow rate (MFR) during the peak flow period from individual teats within a single milking. A method to use MFR, teat-end vacuum and pulsation characteristics measured with this device was developed to estimate teat-end tissue congestion. The changes in teat-end thickness, and changes in teat canal cross sectional area, induced by congestion are small, hence a high precision device is required to detect the resulting subtle changes in MFR. No device has been described in the literature that can apply multiple experimental milking treatments within a single milking while simultaneously recording quarter level response data. This within-milking approach accounts for non-linearity as total milk mass increases and is independent of any effect of milk hose slope and positioning. Sources of variability exist in MFR within an individual quarter, from quarter to quarter, between cows and from day to day. Understanding and controlling for these natural sources of variation is critical for the successful deployment of the Mi4 in milking experiments. Experimental results demonstrate that the Mi4 equipment and methods can detect changes in quarter MFR as small as 2% by applying treatments within the peak flow period of individual quarters, thus making it a useful tool for milking machine research. Highlights· A quarter milking analysis device is developed and demonstrated. · Variations in milk flow were lower at the quarter level than at the cow level. · Data from 11 quarters was sufficient to detect a 12% change in milk flow. · Cow quarter milk flow profiles should be screened prior to treatment application. [ABSTRACT FROM AUTHOR]

This paper expands the historical “Planar model” equation for inertial tree shakers using stacked counter-rotating eccentric-mass energy-wheels and accounts for coupled moments using a “Planar Force and Moment Model”. The energy-wheel configuration utilised by many tree shakers creates planar forces and coupled moment maxima and minima. When the centrifugal acceleration force vectors of each energy-wheel are aligned, this creates a force maximum, acting radially about the tree. The stacked energy-wheels assembly produces a coupled moment due to the centrifugal acceleration force vectors acting on a lever arm. The lever arm vectors extend from a coordinate system coincident with the shaft centre line, and between the upper and lower energy-wheels centre of gravity. A coupled moment maximum occurs when the energy-wheel force vectors are opposing, the planar force is a minimum. The shaker head will roll, pitch, and yaw about the tree trunk due to the instantaneous coupled moment. The rotational and non-normal planar forces are more likely to cause tree trunk bark injury. Subsystems, such as lubricated pads and slings, are required to mitigate transmission of damaging forces. The Planar Force and Coupled Moment Model identifies the force causing vertical tree displacement. Though the Planar model shows that the timing of the energy-wheels produces the observed bi-directional pattern of force maxima, addition of the Coupled Moment shows that timing cannot eliminate non-normal forces. The new model provides a more complete representation of forces applied to the tree and could be used to optimise design for reduced tree damage. [ABSTRACT FROM AUTHOR]

Plug seedlings are increasingly used in vegetable cultivation in Japan, because they are suitable for machine operations and are disease resistant; however, in cabbage cultivation, variation in seedling growth affects plant growth after transplanting to the field, and eventually, harvesting all the cabbages at the same time is not possible. In this paper, a simulation model used to express the growth variation in cabbage plug seedlings is proposed to reveal their cultivation characteristics and consider a cultivation technique that would produce uniform growth among seedlings. In this simulation model, the mutual shading among neighbouring plug seedlings resulting from high-density planting, which is one of the factors of variation in seedling growth, was modelled. The model parameters were obtained from the results of a cultivation experiment comparing growth against the light quantity that seedlings could receive; however, there were differences between the growth of a single seedling in the cultivation experiment and the growth of the plug seedlings. It is believed that growth rate and mass would be greater for a single seedling than for the plug seedlings. This simulation was able to express the growth variation of the actual plug seedlings by adjusting the model parameters. [Copyright &y& Elsevier]

Vibratory harvest is the most appropriate and efficient way to harvest Chinese hickory (Carya cathayensis Sarg.) nuts because of the hilly growth environment and scattered shooting architecture. To develop a mechanical harvester that can be adapted to different Chinese hickory trees, a three-dimensional (3D) model of the tree should be obtained and its dynamics parameters identified. This paper introduces an approach to reconstruct a 3D Chinese hickory tree without foliage using two images with different view angles, and then illustrates a dynamics analysis for the reconstructed tree. Two-dimensional (2D) branches were roughly segmented from the image by the “stripe programming” method, and refined by the ribbon snake model. After extracting the skeleton of 2D branches, a binary-directed tree representing 2D tree structure was established. Under the topology and epipolar constraints, the branch correspondences between two images could be easily found. To improve the accuracy, curve reconstruction under the minimum curvature constraint instead of point-based reconstruction was employed. The diameters of branches from the base to the tip were parameterised as a linear equation. Using the 3D model of the Chinese hickory tree, its dynamics analysis was solved by finite element software (ANSYS Workbench). Compared with the results of the impact tests, a predicted optimal vibration frequency of trunk shaker can be found eventually. It indicates that dynamics analysis using 3D model of tree reconstructed by the proposed method is effective. [Copyright &y& Elsevier]

When olives are harvested, local presses dispose of olive husk, the residue of the pressing process, transporting it to Olive Waste Management Centres (OWMC). Once there, the husk is emptied into pools to be classified, stored and then processed to obtain olive pomace oil and thermal and electric energy. Olive pomace oil extracted mechanically offers benefits over oil extracted chemically, both in terms of its culinary properties and in terms of its market price. This paper describes a decision model whose objective function seeks to maximise the quantity of olive pomace oil by improving the efficiency of mechanical extraction at OWMC. To improve this efficiency, a husk management decision model has been developed to cope with nonlinear husk pooling relationships over a multistage period. The convergence difficulties of mixed integer nonlinear optimisation in the decision model are dealt with by means of a novel multistage iterative linear formulation based on the first order Taylor approximation. The output accuracy and convergence of the proposed model is compared with that of a relaxed mixed integer nonlinear optimisation model. Finally, a real case study located in the south of Spain is described. In this study, by using the linear decision model the total amount of olive pomace oil was 10% greater than that obtained from the current procedure implemented at OWMC. [ABSTRACT FROM AUTHOR]

Controlled traffic farming (CTF) maintains the same machinery wheel tracks in cropping fields year after year, thereby isolating the impacts of traffic compaction from the soil used for crop growth. Benefits of CTF include improved energy efficiency, soil health, crop yield, timeliness and economics. The successful adoption of CTF in the Australian grain and cane industries has been largely based on a limited equipment suite and flat to mildly sloping topography. The Tasmanian vegetable industry faces a very different scenario, with a wide diversity of machinery, and topography ranging from gently to steeply undulating. Two key technical challenges to the adoption of CTF in vegetable and mixed cropping were investigated – 1) working and track width compatibility of current equipment, and 2) farm layouts suited to steeply undulating topography. Almost no machines are currently compatible with a common track or working width, although some are suitable for modification to enable CTF operation. Some harvest machinery (e.g. single row potato harvesters) provides few options for change. Seasonal CTF represents a possible starting place for adoption until more compatible machinery is available. Findings in relation to farm layouts are reported in a companion paper (McPhee, Neale, & Aird, 2013). [Copyright &y& Elsevier]

Abstract: Animal forage plays an important role in agriculture. To maintain the silage quality during storage, preserving it from decomposition by wrapping the harvested crop with plastic stretch film is crucial. Any failure in the preserving process permits the infusion of oxygen, which allows the growth of undesirable aerobic microorganisms and silage decomposition. To study the state of the silage, temperature inside the stack could be used as indicator of decomposition. However, no previous study has developed a model that can detect decomposition based on abnormal temperature variations inside a silage stack. The first objective of this paper was to develop a structured nonlinear model to estimate the dynamics of temperature variations measured by a wireless sensor network-based monitoring system (nRF95E) inside a silage bale and stack prior to the decomposition process. The requirement of a robust nonlinear model is that sensor nonlinearities that are inherent in nature are considered. The results showed that a Hammerstein-Wiener (HW) model with sigmoid network performed the best in terms of percentage of fit (91.70%) between the measured and simulated output. The second objective was to estimate the length of time required to detect the decomposition process after the airtight seal was punctured using the model. The error between the predicted model output and the sensor readings exceeded a preset threshold interval 17 days after the cover film was punctured and 9 days after the decomposition process was detected due to the odour released. [Copyright &y& Elsevier]

The amount of material other than grain (MOG) is an important quality parameter in grain products. The amount of chaff and straw (MOG) in the harvested grain depends highly on the combine harvester settings. On-line knowledge of the grain cleanness could be used to adapt the settings of the threshing and cleaning section in order to keep the proportion of MOG below a desired set point. To allow on-line monitoring of this proportion of MOG, a multispectral vision sensor is developed which creates a virtual image with maximal contrast between kernels and MOG to allow classification of each individual pixel. By calculating the proportion of MOG pixels, a measure for the weight percentage MOG in the sample is then obtained. In this paper, the selection of a combination of a few wavebands which contain sufficient information for adequate discrimination between kernels and MOG is described. For this purpose, hyperspectral measurements of pure kernels and chaff and straw from different varieties of wheat have been acquired to construct a training set where the pixels in the acquired images serve as the samples and the intensities at the different wavelengths as the variables. Using this training set, the best combination of five wavebands in the range from 400 to 900nm with respect to the classification of individual pixels in an image as either kernel or MOG has been selected by means of genetic algorithms. This combination of selected wavebands will then be used to build a multispectral vision sensor. [Copyright &y& Elsevier]

The main objective of this paper is to present a yield monitor specifically designed for the implementation of precision agriculture in sugar cane crops. The overall system includes a mass flow sensor, a global positioning system receiver, and a data acquisition system. The concept for the sensor is based on the sugar cane yield monitor sensor developed previously at The State University of Campinas. A modified version of the sensor was designed to address the specific needs of a harvesting system, including several sensors to eliminate signal interference, and to monitor the harvesting operation. Field testing of the sugar cane yield monitor system was done during the 2004–2005 harvesting season. The system was mounted on a Case 7700 sugar cane harvester. In order to evaluate the accuracy of the system, each loaded truck was weighed on an electronic platform scale upon arrival at the sugarcane mill. The results showed that the output of the sugar cane yield monitor and the harvested load weight present a correlation of 0·66, and the system performance was stable and reliable during tests. A sugar cane yield map was generated in a 43ha area plot of a sugar plantation, located in Araras, the state of São Paulo, Brazil. The results showed that the yield monitor designed and evaluated is accurate, with a mean error of 4·3% where the maximum error never exceeds 6·4%, and is capable of measuring the yield variability. [Copyright &y& Elsevier]

When harvesting citrus, the ability of the harvester to select the harvested fruit by size is very important because there are two fruit crops present on the Valencia orange tree. Only the largest mature fruit is to be harvested and the half-size immature fruit crop must remain on the tree to mature for the following season. The conical-disc picking head described in this paper has the additional capability of mechanically harvesting fruit selected by size within a small size range which is within the wider normal size range of the mature crop. A small-scale self-powered prototype picking head was constructed which could be mounted either on a utility or forklift for performance trials in an orchard. The picking head has slowly rotating spindles arranged in groups of four at 100mm centres. Nine rubber conical-discs are mounted on each spindle to grip, rotate, and thus pick any fruit between 70 and 86mm in diameter that is gently pushed between the elastic discs. The picked fruit is retrieved from the tree and deposited into a delivery chute by the picking head. The picking head tested is suitable for installation on a mobile harvester to pick the fruit from an area of tree foliage, alternatively a small group of four spindles could be used to pick individual pieces of fruit. [Copyright &y& Elsevier]

The harvesting of citrus fruit represents 35–45% of total production cost. Hence, an improvement in the efficiency of this one operation has a significant effect upon enterprise viability and profitability. The traditional manual harvesting method is very labour intensive, and thus expensive. Mechanical harvesting methods have been widely researched and significantly improved. This is illustrated by the large amount of research data available and reviewed in this paper. The performances of the air shaking, trunk shaking, limb shaking and canopy shaking mechanical harvesting systems are briefly summarised. The results of several tree shaping and orchard layout studies have been included because the operating environment of the mechanical harvester affects its performance. The research results show that maximum harvester performance and maximum orchard productivity are not necessarily mutually exclusive, the correct choices of harvesting system and orchard layout can optimise both aspects. Quality fruit selection is very desirable because it achieves the maximum fruit price through the supply of the highest-quality fruit. This review has found that none of the mechanical systems investigated have matched the high-quality selection ability of manual pickers. Hence, this review also includes the results of research into alternative methods of maximising manual picker productivity in order to minimise the cost of manual picking. [Copyright &y& Elsevier]

At the Institute of Agricultural and Environmental Engineering (IMAG B.V.) an autonomous harvesting robot for cucumbers was developed and tested in a greenhouse in autumn 2001. Analysis of the harvest process had revealed that at a 2 ha Dutch production facility four robots are needed to replace the skilled human work force during the peak season. Then assuming a success rate of 100%, a harvest cycle might take at most 10 s per cucumber fruit. In this paper the results of the field test of the harvesting robot are reported and analysed in view of the performance criteria mentioned above. Cucumbers (Cucumis sativus cv. Korinda) were grown in a high-wire cultivation system. In four independent experiments the robot was tested. The average success rate was 74·4%. The majority of failures originated from inaccurate positioning of the end-effector at the stalk of the fruit. It was found to be a great advantage that the system was able to perform several harvest attempts on a single cucumber from different harvest positions of the robot. This improved the success rate considerably. A single successful harvest cycle took 65·2 s per cucumber. Since not all attempts were successful, a cycle time of 124 s per harvested cucumber was measured under practical circumstances. The test confirmed the ability to harvest more than one cucumber using a single set of images which reduced the cycle time of a successful harvest to 56·7 and 53·0 s if two or three cucumbers were harvested. To bridge the gap between the measured performance and the design specifications, future research focuses on improving the success rate, faster hardware and software for image processing and motion planning as well as the reduction of the motion time of the manipulator. [Copyright &y& Elsevier]

The resources used in the collection of residual biomass, originating from the pruning operations of olive trees, by means of chippers fed by pick up headers were determined. The chippers were evaluated for the harvesting of the ligneous materials aligned between the crop lines. The resources employed were measured as labour hour per hectare, machine hours per hectare and fuel consumption. This quantification permits the economic analysis based on knowing the prices of these resources in a particular moment. The results show that manual alignment takes 5hha−1, the chipper takes 1.6h of machineryha−1and 4.8h of manhha−1. The fuel consumption is 4.75l of gas–oilhha−1, obtaining 1.98t of dried biomass per hectare. [Copyright &y& Elsevier]