Development of a novel mechatronic system for mechanical weed ...

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Results and discussion 62 Figure 5.3 Block diagram of the VI for detection of the plant centre position
5.1.2 Results of the accuracy test Results and discussion The accuracy tests conducted on the row with 5 mm wood sticks proved the Nyquist–Shannon sampling theorem (Jerri 1977) that the sampling distance during the detection needs to be at least two times lower than the size of the objects. A number of numeric calculations and I/O operations with a sampling distance lower than 5 mm can overrun the allowed time limits predicted for VI execution and cause delays in execution of the main hoeing algorithm in real- time. Because of that, the size of the object which can be detected with the developed system is limited to 10 mm. The accuracy tests conducted on the row with 10 mm wood sticks showed that both of the sensors can be used for fairly accurate detection of the object. All the wood sticks in the experimental row were detected with the RGB sensor as objects sized between 5 mm and 20 mm when sampling distance was 5 mm and as objects sized between 2 mm and 20 mm when sampling distance was 2 mm. The dispersions of the detected objects size generated by RGB and laser sensor for experiments with 2 mm and 5 mm sampling distance are presented in Figure 5.4. Obviously, the size of the objects detected with RGB sensor frequently exceeds the size of the measured objects. As an argument why such an error appears is the shape and size of the fibre optic sensor’s light emitter. The spot diameter of the light emitter is around 5 mm and the sensor can detect the object when approximately one half of the emitted light returns to the receiver. It can happen two times, first when the sensor approaches the object from the front side and second time when the sensor leaves the object on the back side. According to this explanation the number of impulses which corresponds to one object can be higher up to 2 impulses per object for sampling distance 5 mm and up to 5 impulses per object for sampling distance 2 mm, depending on the RGB sensors position when the sampling executes. As mentioned before, with a sampling distance 2 mm an overrun of the allowed time limits predicted for VI execution can appear and that is the reason why some of the wood sticks were detected as 2 mm, 4 mm and 6 mm sized 63
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Institut für Landtechnik der Rhein
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Development of a novel mechatronic
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Kurzfassung Entwicklung eines neuar
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Acknowledgements Acknowledgements M
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Table of contents Table of contents
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Glossary of abbreviations and symbo
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Symbol Unit Description Mmmax Nm Ma
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Symbol Unit Description Glossary of
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ωold ωout rad s -2 Latest rotatio
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Introduction The most frequently us
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Introduction application that had p
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Introduction be to go from a system
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Introduction limited and environmen
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Introduction than 40 years before g
Page 30 and 31: Introduction techniques. It is know
Page 32 and 33: Introduction Sowing and planting al
Page 34 and 35: Introduction Inter-row weeding syst
Page 36 and 37: Introduction 18 Figure 1.3 Inter-ro
Page 38 and 39: State of the art 20 Figure 2.1 a) F
Page 40 and 41: State of the art cylinder rotates a
Page 42 and 43: State of the art 1998). This device
Page 44 and 45: State of the art 26 2.2 Detection o
Page 46 and 47: State of the art The fluorescence s
Page 48 and 49: Definition of the problem and resea
Page 51 and 52: 4 Materials and methods 4.1 Detecti
Page 53 and 54: Materials and methods Figure 4.1 a)
Page 55 and 56: Materials and methods Figure 4.3 a)
Page 57 and 58: 4.1.2 Data acquisition 4.1.2.1 Hard
Page 59 and 60: 4.1.4 Test objects Materials and me
Page 61 and 62: Materials and methods become a poss
Page 63 and 64: Materials and methods environments
Page 65 and 66: Materials and methods dimensions ne
Page 67 and 68: Materials and methods (PFM). As the
Page 69 and 70: Materials and methods A command sig
Page 71 and 72: Materials and methods The drive con
Page 73: Materials and methods Another tool
Page 76 and 77: Results and discussion 58 Figure 5.
Page 82 and 83: Results and discussion objects. Acc
Page 84 and 85: Results and discussion Plant positi
Page 86 and 87: Results and discussion Plant positi
Page 88 and 89: Results and discussion 70 5.1.4 Dis
Page 92 and 93: Results and discussion Connection b
Page 94 and 95: Results and discussion 76 5.2.1 Opt
Page 96 and 97: Results and discussion xmi1 = ( RLA
Page 98 and 99: Results and discussion With the inv
Page 100 and 101: Results and discussion 82 Horizonta
Page 102 and 103: Results and discussion 84 5.2.4 Sel
Page 104 and 105: Results and discussion 86 5.2.5 Dis
Page 106 and 107: Results and discussion Conventional
Page 108 and 109: Results and discussion Since the fi
Page 110 and 111: Results and discussion To avoid con
Page 112 and 113: Results and discussion As the size
Page 114 and 115: Results and discussion 96 5.3.4 Alg
Page 116 and 117: Results and discussion 98 V = zc( t
Page 118 and 119: Results and discussion corresponds
Page 120 and 121: Results and discussion 102 5.3.6 Me
Page 122 and 123: Results and discussion hoeing accur
Page 124 and 125: Results and discussion between the
Page 126 and 127: Results and discussion distance fro
Page 128 and 129: Results and discussion Distribution
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Results and discussion cuts are ran
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Results and discussion Forward spee
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Results and discussion x [mm] Distr
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Results and discussion The experime
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6 Summary Summary Neither a mechani
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Summary The third part of the work
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7 Conclusions Conclusions The prese
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8 References References Agrios, G.
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References in California's Sacramen
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References Johnson, W C and Mullini
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References Schans, D. v. d. et al.
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List of figures List of figures Fig
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List of figures Figure 5.24 Scheme
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Plant position 9 Appendix Table 9.1
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Plant position Table 9.3 Detection
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Personal data Education About the a
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