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

More documents

Recommendations

Info

State of the art 1998). This device consists of a 30 cm diameter rotating disk that rotates on an axis parallel to both the ground and direction of travel. Two knives, attached with springs opposite to each other on the perimeter of the disk, can stay retracted inside the disk area or they can fold out depending on the intensity of the rotational speed, due to the balance between the centrifugal force and the spring force. The disk is actuated by a hydraulic motor whose exact rotational speed is controlled by a hydraulic controller. The controller adjusts the rotational speed value according to the detected plant position. The detection unit consists of a combination of three infrared transmitters and receivers placed above each other on a gantry on different plant height levels. A weighted summation of the signals from three sensors is combined to a single signal which is a base for processing. During the weeding operation the motor rotates permanently at 850 rpm with knives extended to the working position, until the detection system does not detect a beet plant. After a beet has been recognised the rotational speed decreases to 700 rpm with almost immediate fold-in of the knives. At Cranfield University in Silsoe, UK, a rotating disk weeder has been developed (Dedousis et al. 2006). It consists of a thin rotating disc with a cut-out sector and a bevel cut back at its circumference (see Figures 2.5 and 2.6). The disc acts in a horizontal plane and operates at a fixed distance parallel to the plant row. This allows the disc to work the ground in both the intra- and inter- row areas. As the disk rotates, the weeds are cut by the sharp edge along the perimeter. The bevelled cut-out section allows for one plant per revolution to stay in the protected area without the contact with the disc. Assuming a plant distance of 300 mm, the ideal disc geometry was calculated to have a 175 mm diameter and 130° cut-out section. A bevel shape can be modified on the disk to achieve different kinds of weed cutting. Also, the inclination angle and working depth are adjustable depending on the plant type and soil conditions. Preliminary tests have shown that up to 60 % of weeds within an 80 mm radius can be eliminated, and up to 80% of weeds at greater radii. In a test in September 2006, 77 % of weeds were judged to be removed and only one plant out of 24 showed damage. Angular error of the disc was also quite low, normally less than 10°. A disadvantage of this tool is that it is limited to plant 24
State of the art spacings of 25 cm or above because of the current size and geometry. The disk geometry would have to be redesigned for plant systems with intra-row distance less than 25 cm. Also, to achieve optimal weeding the machine would either require two passes, one on each side of the plant row, or have to include two disks per plant row. Figure 2.5 Illustration of the hoeing concept using the rotating disk (Dedousis et al. 2006) Figure 2.6 Rotating disk weeder a) the toolframe with two rotary cultivator units without inter-row cultivation blades b) the toolframe with one rotary cultivator without inter-row cultivation blades mounted on the front of the tractor (1 - rotating disc, 2 - camera for row following, 3 - toolframe, 4 - tool carrier wheel with suspension allowing cultivation depth control (Dedousis et al. 2007) 25
Page 1 and 2: Institut für Landtechnik der Rhein
Page 3 and 4: Development of a novel mechatronic
Page 5 and 6: Kurzfassung Entwicklung eines neuar
Page 7 and 8: Acknowledgements Acknowledgements M
Page 9 and 10: Table of contents Table of contents
Page 11 and 12: Glossary of abbreviations and symbo
Page 13 and 14: Symbol Unit Description Mmmax Nm Ma
Page 15 and 16: Symbol Unit Description Glossary of
Page 17: ωold ωout rad s -2 Latest rotatio
Page 20 and 21: Introduction The most frequently us
Page 22 and 23: Introduction application that had p
Page 24 and 25: Introduction be to go from a system
Page 26 and 27: Introduction limited and environmen
Page 28 and 29: 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 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
Page 130 and 131:
Results and discussion cuts are ran
Page 132 and 133:
Results and discussion Forward spee
Page 134 and 135:
Results and discussion x [mm] Distr
Page 136 and 137:
Results and discussion The experime
Page 139 and 140:
6 Summary Summary Neither a mechani
Page 141 and 142:
Summary The third part of the work
Page 143 and 144:
7 Conclusions Conclusions The prese
Page 145 and 146:
8 References References Agrios, G.
Page 147 and 148:
References in California's Sacramen
Page 149 and 150:
References Johnson, W C and Mullini
Page 151 and 152:
References Schans, D. v. d. et al.
Page 153 and 154:
List of figures List of figures Fig
Page 155 and 156:
List of figures Figure 5.24 Scheme
Page 157 and 158:
Plant position 9 Appendix Table 9.1
Page 159 and 160:
Plant position Table 9.3 Detection
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169:
Personal data Education About the a
show all

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?