Festo unveils new bionic grippers

Small, lightweight and powerful: Festo demonstrated how energy-efficient gripping principles found in nature can be applied in automation technology with the NanoForceGripper and the research project “PowerGripper” at Hanover Trade Fair 2012.

Photo: Festo AG & Co. KG

Gripping, holding and setting down objects are vital production processes that are performed using automation technology. Conventional gripper solutions, however, are not always very energy-efficient when it comes to their gripping force to weight ratio. Nature, on the other hand, abounds with perfect examples of principles of efficiency. Festo’s mission with the Bionic Learning Network is to transfer these principles to automation technology. This is because the best way of optimising energy consumption in industry is to exploit existing potential in production processes.

Energy-efficient gripping based on the model of the gecko
With the NanoForceGripper, engineers from the Festo Bionic Learning Network have developed a gripper whose suction cup-like components are modelled on the pads of a gecko. They cling reliably and permanently to the surfaces of the object to be gripped thanks to tiny, intermolecular forces of attraction called van der Waals forces. A key component of the gripper is the Gecko® Nanoplast® tape on its underside with 29,000 gripping elements per cm².

Once a part is gripped, it is permanently held by the gripper without the need for energy. A counteracting force is only needed when it is time to release the bond and set down the gripped object. The tape is peeled off by means of a structure with Fin Ray Effect®, which is modelled on the tail fin of a fish. The spring forces are released by a push-push mechanism that deforms the structure from a straight surface to a curved one. The effective holding surface covered by the tape becomes increasingly smaller until the gripped object is released gently. Energy-free holding and energy-efficient gripping are an innovation for grippers that work with a push-push mechanism. In particular, this type of energy-free holding of objects was not previously possible.

The NanoForceGripper can grip especially delicate objects with smooth surface such as glasses or displays without almost any energy. The new technology complements the existing pneumatic gripping technology and can be used as needed and as appropriate to the application.

PowerGripper – inspired by a bird’s beak
The PowerGripper is a university project developed within the framework of the Bionic Learning Network. Students examined variants that took the form of planar grippers, spatial grippers and point grippers – modelled on the complex kinematics of a bird’s beak. The motion principle employed in the PowerGripper is called Watt’s linkage by engineers. The developers of the gripping system used the fluidic muscle from Festo to create the bionic principle, combining it with the production process of metal laser melting.

This gripper has a very good force to weight ratio thanks to the lightweight construction, the extremely lightweight pneumatic muscles and the use of a titanium alloy (Ti6Al-4V) as the material for the basic components. As a research project, the PowerGripper demonstrates numerous possibilities for the development of new gripping systems. The lightweight yet very stable structure of the gripper means that the entire system behind it can also be lightweight and as a result operated with greater energy efficiency.

Further information can be found at: www.festo.com/bionic