Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Collision-free inverse kinematics of the redundant seven link manipulator used in a cucumber harvesting robot
Henten, E.J. van; Schenk, E.J.J. ; Willigenburg, L.G. van; Meuleman, J. ; Barreiro, P. - \ 2010
Biosystems Engineering 106 (2010)2. - ISSN 1537-5110 - p. 112 - 124.
autonomous robot
The paper presents results of research on an inverse kinematics algorithm that has been used in a functional model of a cucumber-harvesting robot consisting of a redundant P6R manipulator. Within a first generic approach, the inverse kinematics problem was reformulated as a non-linear programming problem and solved with a Genetic Algorithm (GA). Although solutions were easily obtained, the considerable calculation time needed to solve the problem prevented on-line implementation. To circumvent this problem, a second, less generic, approach was developed which consisted of a mixed numerical-analytic solution of the inverse kinematics problem exploiting the particular structure of the P6R manipulator. Using the latter approach, calculation time was considerably reduced. During the early stages of the cucumber-harvesting project, this inverse kinematics algorithm was used off-line to evaluate the ability of the robot to harvest cucumbers using 3D-information obtained from a cucumber crop in a real greenhouse. Thereafter, the algorithm was employed successfully in a functional model of the cucumber harvester to determine if cucumbers were hanging within the reachable workspace of the robot and to determine a collision-free harvest posture to be used for motion control of the manipulator during harvesting. The inverse kinematics algorithm is presented and demonstrated with some illustrative examples of cucumber harvesting, both off-line during the design phase as well as on-line during a field test.
Classification of sugar beet and volunteer potato reflection spectra with a neural network and statistical discriminant analysis to select discriminative wavelengths
Nieuwenhuizen, A.T. ; Hofstee, J.W. ; Zande, J.C. van de; Meuleman, J. ; Henten, E.J. van - \ 2010
Computers and Electronics in Agriculture 73 (2010)2. - ISSN 0168-1699 - p. 146 - 153.
hyperspectral data - winter-wheat - crop - identification - indexes - corn
The objectives of this study were to determine the reflectance properties of volunteer potato and sugar beet and to assess the potential of separating sugar beet and volunteer potato at different fields and in different years, using spectral reflectance characteristics. With the ImspectorMobile, vegetation reflection spectra were successfully repeatedly gathered in two fields, on seven days in 2 years that resulted in 11 datasets. Both in the visible and in the near-infrared reflection region, combinations of wavelengths were responsible for discrimination between sugar beet and volunteer potato plants. Two feature selection methods, discriminant analysis (DA) and neural network (NN), succeeded in selecting sets of discriminative wavebands, both for the range of 450–900 and 900–1650 nm. First, 10 optimal wavebands were selected for each of the 11 available datasets individually. Second, by calculating the discriminative power of each selected waveband, 10 fixed wavebands were selected for all 11 datasets analyses. Third, 3 fixed wavebands were determined for all 11 datasets. These three wavebands were chosen because these had been selected by both DA and NN and were for sensor 1: 450, 765, and 855 nm and for sensor 2: 900, 1440, and 1530 nm. With the resulting three sets of wavebands, classifications were performed with a DA, a neural network with 1 hidden neuron (NN1) and a neural network with two hidden neurons (NN2). The maximum classification performance was obtained with the near-infrared sensor coupled to the NN2 method with an optimal adapted set of 10 wavebands, where the percentages were 100 ± 0.1 and 1 ± 1.3% for true negative (TN) classified volunteer potato plants and false negative (FN) classified sugar beet plants respectively. In general the NN2 method gave the best classification results, followed by DA and finally the NN1 method. When the optimal adapted waveband sets were generalized to a set of 10 fixed wavebands, the classification results were still at a reasonable level of a performance at 87% TN and 1% FN for the NN2 classification method. However, when a further reduction and generalization was made to 3 fixed wavebands, the classification results were poor with a minimum performance of 69% TN and 3% FN for the NN2 classification method. So, these results indicate that for the best classification results it is required that the sensor and classification system adapt to the specific field situation, to optimally discriminate between volunteer potato and sugar beet pixel spectra
Development of a crop health sensor (CHS) : early detection of apple scab in apple leaves
Wenneker, M. ; Zande, J.C. van de; Meuleman, J. - \ 2010
Ontwikkelingen schurftherkenning fruit
Zande, J.C. van de; Meuleman, J. ; Wenneker, M. - \ 2010
Gewasbescherming 41 (2010)1. - ISSN 0166-6495 - p. 15 - 15.
fruitteelt - fruitgewassen - scabiës - boomgaarden - gewasbescherming - pesticiden - sporing - spuiten - meeldauw - spuitdoppen - fruit growing - fruit crops - scabies - orchards - plant protection - pesticides - tracking - spraying - mildews - fan nozzles
In het EU-FP6 ISAFruit-project wordt een Crop Adapted Spray Application-systeem voor precisiegewasbescherming in de fruitteelt ontwikkeld. Het systeem garandeert een veilige toediening van gewasbeschermingsmiddelen in boomgaarden afgestemd op de grootte van de boom en de geldende weersomstandigheden. Het systeem wordt beschreven
Advanced spraying techniques in fruit growing--the ISAFRUIT project--towards safer and better quality of fruit
Wenneker, M. ; Zande, J.C. van de; Meuleman, J. ; Doruchowski, G. ; Balsari, P. ; Marucco, P. - \ 2009
Communications in agricultural and applied biological sciences 74 (2009)1. - ISSN 1379-1176 - p. 67 - 74.
In 2006 the project ISAFRUIT (www.isafruit.org)--"Increasing fruit consumption through a trans disciplinary approach leading to high quality produce from environmentally safe, sustainable methods"--was launched within the 6th Framework Program of the EC. Within the project's work package ECOFRUIT (WP 5.1 - Safe European fruit from a healthy environment) a Crop Adapted Spray Application (CASA) system is developed. This system is developed to ensure efficient and safe spray application in orchards according to actual needs and with respect to the environment. The system consists of three components: 1. Crop Identification System (CIS), 2. Environmentally Dependent Application System (EDAS), and 3. Crop Health Sensor (CHS). A sprayer prototype able to automatically adapt spray and air distribution according to the characteristics of the target, to the level of crop disease and to the environmental conditions is under development
Early detection of apple scab in apple leaves; development of a crop health sensor (CHS)
Zande, J.C. van de; Wenneker, M. ; Meuleman, J. - \ 2009
In: SuproFruit 2009 10th Workshop on spray application techniques in fruit growing. 30 sept -2 october 2009, Wageningen, The Netherlands. - Wageningen : Wageningen UR, Plant Sciences Group - p. 28 - 29.
Classification of sugar beet and volunteer potato spectra using a neural network to select wavelenghts
Nieuwenhuizen, A.T. ; Hofstee, J.W. ; Zande, J.C. van de; Meuleman, J. ; Henten, E.J. van - \ 2009
In: Proceedings of the Joint International Agricultural Conference (JIAC2009), Wageningen, The Netherlands, 6 - 8 July, 2009. - Wageningen : Wageningen Academic Publishers - ISBN 9789086861132 - p. 313 - 320.
Classification of sugar beet and volunteer potato spectra using a neural network to select wavelenghts
Nieuwenhuizen, A.T. ; Hofstee, J.W. ; Zande, J.C. van de; Meuleman, J. ; Henten, E.J. van - \ 2009
In: Book of abstracts, Joint International Agricultural Conference( JIAC2009), Wageningen, the Netherlands, 6 - 8 July, 2009. - Wageningen : Wageningen Academic Publishers - ISBN 9789086861149 - p. 36 - 36.
Development of a crop health sensor (CHS) to minimize spray applications in orchards
Zande, J.C. van de; Meuleman, J. ; Wenneker, M. - \ 2009
In: 61st International Symposium on Crop Protection. May 19th, 2009, Gent, Belgium. - - p. 18 - 18.
Developments of advanced spray techniques in the ISAFruit project - towards safer and better quality fruit
Zande, J.C. van de; Wenneker, M. ; Doruchowski, G. ; Balsari, P. ; Achten, V.T.J.M. ; Meuleman, J. ; Holownicki, R. ; Marucco, P. - \ 2008
In: Proceedings 1st North American Conference on Precision Fruit Spraying, Canandaigua NY, 8-9/4/2008. - Geneva NY, USA : Cornell University - p. 33 - 38.
Collision-free inverse kinematics of a 7 link cucumber picking robot
Henten, E.J. van; Schenk, E.J.J. ; Willigenburg, L.G. van; Meuleman, J. ; Barreiro, P. - \ 2008
Acta Horticulturae 801 (2008). - ISSN 0567-7572 - p. 579 - 586.
The paper presents results of research on inverse kinematics algorithms to be used in a functional model of a cucumber harvesting robot consisting of a redundant manipulator with one prismatic and six rotational joints (P6R). Within a first generic approach, the inverse kinematics problem was reformulated as a non-linear programming problem and solved with a generic algorithm. Solutions were easily obtained, but the considerable calculation time needed to solve the problem prevented on line implementation. To circumvent this problem, a second, less generic approach was developed consisting of a mixed numerical-analytic solution of the inverse kinematics problem exploiting the particular structure of the P6R manipulator. This approach facilitated rapid and robust calculation of the inverse kinematics of the cucumber harvester. During the early stages of the cucumber harvesting project, this inverse kinematics algorithm was used to off-line evaluate the ability of the robot to harvest cucumbers using 3D-information of a cucumber crop obtained in a real greenhouse. Thereafter, the algorithm was employed successfully in a functional model of the cucumber harvester to determine if cucumbers were hanging within the reachable workspace of the robot and to determine a collision-free harvest posture to be used for motion control of the manipulator during harvesting.
Mobiel: Beeldvormende spectroscopie voor gewaskarakterisering
Molema, G.J. ; Meuleman, J. ; Evert, F.K. van - \ 2008
A crop health sensor to minimize spray applications
Zande, J.C. van de; Wenneker, M. ; Meuleman, J. ; Achten, V.T.J.M. - \ 2007
Collision-free inverse kinematics of a 7 link cucumber picking robot
Henten, E. van; Schenk, E. ; Willigenburg, L.G. van; Meuleman, J. ; Barreiro, P. - \ 2007
Measuring the yield gap : technische mogelijkheden voor verbetering van graslandproductiviteit
Meuleman, J. ; Schut, A.G.T. ; Smits, M.C.J. - \ 2006
Wageningen : Plant Research International (Nota / Plant Research International 416) - 36
poaceae - lolium perenne - gewasproductie - gewasopbrengst - productiemogelijkheden - graslanden - nederland - crop production - crop yield - production possibilities - grasslands - netherlands
Imaging Spectroscopy for On-Farm Measurement of Grassland Yield and Quality
Schut, A.G.T. ; Heijden, G.W.A.M. van der; Hoving, I.E. ; Stienezen, M.W.J. ; Evert, F.K. van; Meuleman, J. - \ 2006
Agronomy Journal 98 (2006)5. - ISSN 0002-1962 - p. 1318 - 1325.
infrared reflectance spectroscopy - chemical-composition - calibration transfer - management - regression - chemistry - herbage - models - litter - swards
Grassland management has a large influence on the operating cost and environmental impact of dairy farms and requires accurate, detailed, and timely information about the yield and quality of grass. Our objective was to evaluate imaging spectroscopy as a means to obtain accurate, detailed, and rapid measurements of grass yield and quality. The work consisted of three steps. In the first step, a new mobile measurement system comprising several hyperspectral sensors was constructed and calibrated on measurements collected in six field experiments in the Netherlands in 2 yr. A partial least squares regression model was used to fit parameters derived from hyperspectral images to values of DM (dry matter) yield and quality obtained through destructive sampling. Leave-k-out cross validation showed relative errors of prediction of 8 to 22% (167¿477 kg DM ha¿1 absolute) for DM yield, 21% (0.07 absolute) for the fraction of clover in DM, 6 to 12% for nutrient concentration, 15 to 16% for sugar concentration, and 3 to 5% for feeding values. In the second step, the measurement system was used to predict grassland yield and quality on fields from two farms. In the third step, the absence of calibration data for a specific date was simulated with a leave-harvest-out procedure. Predictions of absolute values were strongly biased due to system instability. Prediction of relative values was good, with a mean absolute error of 183 kg ha¿1 for DM yield. The instability of the measurement system requires that duosampling must be used for prediction of absolute values.
Imspector Mobiel: Beeldvormende spectroscopie voor gewaskarakterisering
Meuleman, Jan - \ 2005
Automatic body condition scoring of dairy cows: extracting contour lines
Pompe, J.C.A.M. ; Graaf, V.J. de; Semplonius, R. ; Meuleman, J. - \ 2005
In: Precision agriculture, 5th European conference on precision agriculture, Uppsala, Sweden, 9-12 June 2005. - Uppsala, Sweden : Swedish inst. of agricultural and environmental engineering - ISBN 9170721416 - p. 243 - 245.
Een mobiel systeem met beeldvormende spectroscopie voor gewaskarakterisering
Meuleman, Jan - \ 2004
Non-destructive assessment of dry matter yield, nutrient content and feeding value of grass swards with imaging spectroscopy
Schut, A.G.T. ; Hendriks, M.M.W.B. ; Evert, F.K. van; Hoving, I.E. ; Meuleman, J. - \ 2004
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