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Autonomous Weeder for Christmas Trees – Basic Development and Tests

Contents

Preface

Sammenfatning

• Robotlugning af juletræer er en realistisk mulighed
  • Baggrund og formål
  • Undersøgelsen
  • Hovedkonklusioner
  • Projektresultater

Summary

• Robotic weeding of Christmas trees is now a realistic possibility
  • Background and purpose
  • The investigation
  • The main conclusions
  • Project results

1 Introduction

2 Previous studies and development work

• 2.1 Recent developments in field robot technology
• 2.2 Specific control related issues

3 Requirements and system concept

• 3.1 Design requirements
• 3.2 System concept
• 3.3 Choice of vehicle concept
• 3.4 Plantation mapping
• 3.5 Route plan generation
• 3.6 Control system development

4 Weeder platform development

• 4.1 Platform selection and modification
  • 4.1.1 Vehicle cover and protection skirts
  • 4.1.2 Vehicle control actuators
• 4.2 Weed cutter selection and development

5 Control system development

• 5.1 Requirements
  • 5.1.1 Procedure of weeder operation
  • 5.1.2 Safety and reliability
• 5.2 Control principles
  • 5.2.1 Vehicle tracking control
  • 5.2.2 Cutter positioning system
• 5.3 System architecture
• 5.4 System hardware and information flows
  • 5.4.1 Control panel
  • 5.4.2 Sensor systems
  • 5.4.3 Digital I/O adaptor and power circuits
  • 5.4.4 Power supply systems
• 5.5 System software
  • 5.5.1 Processing of sensor data
  • 5.5.2 Vehicle tracking control
  • 5.5.3 Cutter positioning control
  • 5.5.4 Safety system
• 5.6 Simulink representations
• 5.7 Simulations and tests of the control system

6 Results

• 6.1 Sensor capabilities and reliabilities
  • 6.1.1 RTK GPS
  • 6.1.2 Tilt meter
  • 6.1.3 Laser scanner
• 6.2 Computer simulations of vehicle behaviours
  • 6.2.1 Route tracking
  • 6.2.2 Cutter positioning system
• 6.3 Tests in plantation model
  • 6.3.1 Route tracking
  • 6.3.2 Precision of weed cutter positioning near trees
  • 6.3.3 Fault and obstruction behaviours
• 6.4 Plantation tests
  • 6.4.1 Plot conditions and preparations
  • 6.4.2 Quality of weeding
  • 6.4.3 Damages to trees

7 Economic feasibility

• 7.1 Calculation method
• 7.2 Chosen parameter values
  • 7.2.1 Purchase price
  • 7.2.2 Weeder performances parameters
• 7.3 Results
• 7.4 Sensitivity analysis

8 Discussion

• 8.1 The ACW platform
• 8.2 The weed mechanical cutter concept
• 8.3 Control system
  • 8.3.1 Vehicle tracking control
  • 8.3.2 Weed cutter arm control
  • 8.3.3 Vehicle fault and obstruction detection and system reaction
• 8.4 Tree mapping and cutter head control
• 8.5 Economic feasibility

9 Conclusion

10 Perspectives

• 10.1 Scientific perspectives
• 10.2 Practical perspectives

11 References

Appendix A

Appendix B

Appendix C

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Version 1.0 November 2005, © Danish Environmental Protection Agency