CROPS EU-project

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WP5: Sweet pepper – protected cultivation

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This workpackage aims to build a demonstrator for sweet pepper production. The focus of the research is on robotic harvesting of sweet pepper fruit.

Research will also emphasize development of generic concepts that can be used to perform other functions such as
planting, attaching plant to supporting wires, pruning, leaf picking, monitoring yield and quality and local crop protection.

Current progress of workpackage (December 2013):

At the current stage of the project the analysis on the different sub-systems for cropping systems and crop manipulation was completed. Moreover, different concepts for fruit and obstacle detection, ripeness determination and localisation and concepts to reach, grasp and detach fruit were investigated. The for the demonstration chosen design is based on the current good practice cropping system of sweet-peppers in the Netherlands. Concepts for a number of cultivation related tasks for sweet-pepper production other than harvesting were analysed. Four tasks were identified to be promising to automate which are: Monitoring, planting, pruning and tying up the plant. A mobile platform that can move between the plant rows, as under development in this project offers opportunities also for plant monitoring. The other tasks are most likely not economically feasible to automate.

In close co-operation with the other workpackes much effort was spent on testing and developping the different demonstrator modules, including suggestions for revision and improvement. Different cameras were tested for their suitability to detect and localize sweet-pepper fruits and obstacles and to determine fruit ripeness. After evaluation a sensor rig with a Time of Flight 3D camera mounted close to a high-resolution colour was assembled.

Obstacle (main plant stem) detection result based on images from the main sensor rig

Two different end-effectors to detach fruits from the plant were developed and analysed: a gripper with an integrated cutting tool with fingers that are based on the Finray principle and a guidance and cutting tool approaching the fruit from below. On both types of end-effectors two mini cameras are mounted: one Time of Flight camera and one colour camera.


Gripper with an integrated cutting tool with fingers that are based on the Finray principle

The first prototype of the manipulator was tested. It was concluded that the considered prototype is suited to harvest pepper fruits. A carrier platform for the robotic arm and the sensor systems was built. The sensor system on the platform is mounted on a linear motorized slide and can be horizontally moved out of the workspace of the robot while the robot is moving.

pepper integrated demonstrator

Demonstratror for harvesting sweet-pepper with all modules integrated

The software of the robot is implemented for the Linux operating system and the middleware ROS. The main software is based on a finite state machine and includes diagnostic tools and performance measures of the harvesting operation. The demonstrator was tested under laboratory conditions (Milestone 16). During these experiments data on the performance and accuracy of the different subsystems was gained. The integrated system was successfully demonstrated to the Dutch pepper growers which are part of the established growers advisory board.

Motion planning simulations

In co-operation with WP13 the economic feasibility for sweet pepper harvesting was calculated. A comparison was made between manual harvesting and fully robotized harvesting, with the return on investment or investment space as a result. With a cycle time of 6 seconds for each harvested product, the sweet pepper robot will be profitable when the price of one robot will be below € 195.000 at an economic and technical life cycle of 5 years. One robot can cover 1.4 Ha of a modern Dutch sweet pepper Greenhouse.

April 2012: first prototype of a manipulator tested for the first time in a sweet-pepper crop




Main partners involved in workpackage 5



Lead partner of this workpackes is Wageningen UR.

Last Updated on Thursday, 02 January 2014 09:32