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

More documents

Recommendations

Info

Results and discussion 86 5.2.5 Discussion of the results conducted by virtual prototyping Virtual prototyping of course has some disadvantages as well. As with any computer simulation, there are real-world elements that cannot be exactly reproduced in a virtual form. While a simulation may show a mechanism to function perfectly, in reality a rather small change in the soil roughness may cause problems. Until now, virtual prototyping technology has not completely rendered physical testing obsolete. However, the role of physical prototypes has now shifted to that of validating the virtual model. After the virtual prototyping process has yielded a design that on the computer appears robust and meets all the design objectives, a physical model can be built to validate the data from the computer model to ensure the design is indeed applicable in real life. However, because most of the problems have been discovered and worked out in the virtual prototyping process, the physical prototype is likely to be nearly ready for manufacture with very few errors. All of these advantages resulted in a drastically reduced time frame, from the idea to the introduction of the first prototype of the intra-row weeding tool. The reduction of costs and time needed for prototype development was one of the major benefits of virtual prototyping.
5.3 Physical prototype of the hoeing equipment Results and discussion After the comprehensive analysis of the results observed with the virtual prototype the first physical prototype of the hoeing tool has been built. The selection of the appropriate driving engine for accurate rotational speed and position control of the hoeing tool required a determination of the average and maximum torque on the axis, during the weeding process in field conditions. 5.3.1 Determination of the maximum torque and nominal speed required To confirm that the designed construction can withstand the maximum load and to observe the torque value, experiments in the field conditions were conducted. The determination of the maximum torque was of crucial significance in order to choose a motor with adequate power for the hoeing tool. In the experiment the rotary hoeing tool with three implemented arms was pulled by a tractor and plugged to the cardan shaft of the tractor over a gear with 10:1 transmission ratio. The aim of the experiments was to acquire information about the forward speed, angular position of the hoeing tool and required torque for hoeing. The forward speed can be calculated if the travelled distance and the time passed are known. Travelled distance in field conditions can be estimated with several methods. Methods which are based on the contact with the soil surface need to be avoided if high accuracy is required, because of the slipping effect which can occur in hard field conditions. One accepted non-contact method for estimation of the travelled distance is with systems based on the Doppler shift effect. Depending on the adjustment, such a system can provide up to 125 impulses per meter of travelled distance, which satisfies accuracy demands in the field experiments. For simple on-line acquisition of the tractor’s forward position an RDS true ground speed sensor (TGSS) was chosen. The angular position of the hoeing was acquired with an incremental encoder attached to the hoeing tool’s shaft. This information was used for calculation of the rotational speed of the hoeing tool. 87
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 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 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 ...

Create successful ePaper yourself

Delete template?

Save as template?