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WP3: Manipulators and End-Effectors

CROPS EU-project

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WP3: Manipulators and End-Effectors

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The objectives of WP3 are the design, modeling, manufacture, start-up and optimization of lowcost, lightweight, modular and compliant manipulators with exchangeable end-effectors and their motion control.

This workpackage is coordinated by the Technical University Munich (DE), Institute of Applied Mechanics.


During the project three manipulator prototypes have been developed. The first prototype has been tested in field experiments for apple and sweet-pepper harvesting. Furthermore, it was integrated into the precision spraying application of grape vine. The second prototype is similar to the first manipulator and used for software and hardware tests in the lab. The third prototype is build up out of fully integrated drive modules. Hence, it is easily possible to change the kinematic configuration. Since the design is more robust, it is suitable for extensive field test. All prototypes were designed and manufactured at the Technische Universität München, Institute of Applied Mechanics.

First Manipulator Prototype

First manipulator prototype in 9 Degree-of-Freedom configuration (left hand side) and with sprayer and cover for the precision spraying application in the 6 degree-of-freedom configuration (right hand side).

Crops manipulator

Crops sprayer manipulator

Third (final) Manipulator Prototype

Due to its modular design, the final manipulator prototype can easily be reconfigured. On the left hand side the 7 degree-of-freedom configuration is shown and on the right hand side, the manipulator is configured in the 9 degree-of-freedom configuration. You can download video clips of the final manipulator prototype in the video section of this webpage.


Final Crops manipulator 7 DoF

Final Crops manipulator 9 DoF

Publications related to the manipulators (for a complete overview see the Dissemination page)

Baur, J.; Pfaff, J.; Ulbrich, H. & Villgrattner, T. (2012), 'Design and development of a redundant modular multipurpose agricultural manipulator''Advanced Intelligent Mechatronics (AIM), 2012 IEEE/ASME International Conference on', Kaohsiung, Taiwan, 823-830.

Pfaff, J.; Baur, J.; Ulbrich, H. & Villgrattner, T. (2012), Development of a multipurpose agricultural manipulator, in 'Proceedings of the First RHEA International Conference on Robotics and associated High-technologies and Equipment for Agriculture'.

Baur, J.; Pfaff, J.; Schuetz, C. & Ulbrich, H. (2013), Dynamic modeling and realization of an agricultural manipulator, in 'Proceedings of XV International Symposium on Dynamic Problems of Mechanics, DINAME'.

Schuetz, C.; Baur, J.; Pfaff, J.; Buschmann, T. & Ulbrich, H. (2014), Multipurpose Redundant Manipulators for Agricultural Tasks, in 'Austrian Robotics Workshop (ARW)'.


While the manipulator is suitable for all three applications of the CROPS project, Festo needs to develop different gripper for handling sweet pepper, apples and graves.

Figure 1: First field test of the manipulator and gripper prototype in a greenhouse close to Wageningen, NL.

The third version of the gripper-prototype for sweet pepper can be seen in figure 1 mounted on the manipulator. On each gripper jaw there are mounted three Finray fingers which are able to adapt to the geometry of the peppers. One of them allows further on a rotative adaption.


Figure 2: Cutting devices for sweet pepper

The sweet pepper needs to be cut from the plant. Therefore Festo manufactured three different types of cutting devices shown in figure 2. The first one bases on a pneumatic linear drive, the second on a pneumatic angle gripper. The third one is special, because it is able to grip the peduncle of the pepper and cut it in one step.

Figure 3: Grippers for apples

For apple harvesting also different versions of the gripper were developed, the last prototype tested in the orchard in Chile in March 2012 can be seen in figure 3. It consists of a long stroke parallel gripper with two membrane jaws. In Chile it was tested, if a third, fixed finger pushing on the stem of the apple can help to optimize harvesting success.

Figure 4: Grippers for grapes

For grapes Festo developed two different grippers, that also were tested in Chile in March 2012. One bases on an angle gripper, the other on a parallel gripper. Both can grip the stem of the grapes and cut it in one step.

Last Updated on Monday, 19 May 2014 15:25