MAVERIC: Modular Autonomous Vehicle
For agricultural surveys, the use of unmanned ground vehicles (UGV) as sensor carriers is becoming increasingly attractive. These vehicles can be equipped with multiple sensing de-vices to achieve a high level of autonomy in order to improve productivity and profitability in agriculture.
This article describes an UGV, which has been developed at ZHAW from scratch especially for the application in agricultural Environments.
Unmanned ground vehicles (UGV) as sensor carriers have been developed for agricultural environments. For this application, special requirements for the UGV must be fulfilled. The system presented here is designed to adapt to the plant row spacing in an orchard with a flexible track width of between 0.8 and 1.2 meters. It uses 29-inch wheels to provide a ground clear-ance of at least 40 centimetres. The wheel axles are driven electrically and differencally by cahin drives (all wheels are separately controllable). The rear axle is tractable, so that a narrow turn radius can be achieved. With currently built-in translation the UGV shows a maximum speed of approx. 30 km/h. The UGV mainly made of aluminium weighs 65 kg and permits a pay load from up to 50 kg. In the UGV a real time control (TwinCAT 3. 1) of the company Beckhoff AG was integrated. This guarantees a high robustness and reliability of controls and sensors. The application of standardised hardware components proven in industry should simplify the integration of sensors, as well as the enlargement of the system. A graphic user interface, which can be run on portable devices, was provided for the interaction with the UGV. The communication is done by WLAN connection. The software components were implemented to be modular, scalable and recyclable. Thus these can be ported on other Beckhoff platforms. By means of a wireless "Dead-Man-Switch" the UGV can be stopped any time, which guaranties security.
During the first field tests steering of the UGV has shown good and quiet vehicle dynamics. Among the rest this is due to shock absorbers as well as the large wheel diameters (29 inches). This is indispensable for a reasonable data collection (little white noise, sharp pictures). In this work the UGV is equipped subsequently with sensors (IMU, cameras, (3D) LiDAR) and a waypoint-based navigation. This allows the UGV to move along defined road points (e. g. GPS co-ordinates), to collect senor data autonomously and to save them locally. By means of this sensor configuration the environment can be modelled, navigation can be extended and as a result the level of autonomy can be raised.
Project start: 16.09.2013
- Layout, detail design, manufacturing, and field testing of a UGV for agricultural applications.pdf (PDF 295,3 KB)
- Conference proceeding of the International Conference of Agricultural Engineering, Zurich, 06-10.07.2014.pdf (PDF 575,6 KB)
- Poster: Autonomous Unmanned Ground Vehicle as Sensor Carrier for Agricultural Survey Tasks.pdf (PDF 746,4 KB)
- MSE Focus Project 2, 2014: TwinCAT 3 based Real Time Control System for the Autonomous Mobile Robot.pdf (PDF 9,0 MB)