Drives and Controls Magazine
Pneumatic ‘hand’ and ‘arm’ can collaborate safely with humans
Published:  01 March, 2019

Festo has unveiled its latest nature-inspired technologies: a pneumatically-operated “hand” and “arm” which can interact safely with people. Both will make their public debut at next month’s Hannover Fair.

The lightweight BionicSoftHand is capable of exerting strong forces. Unlike a human hand, it has no bones. Its five “fingers” consist of flexible bellows structures with air chambers. The bellows are enclosed in a special 3D textile knitted from strong, elastic threads. The textile determines where the structure expands and generates force, and where it is prevented from expanding. The “fingers” bend as soon as they are filled with air. Inertial and tactile force sensors are incorporated in thin, flexible circuit boards that are applied to the textile covering.

The hand is taught tasks uses “reinforcement learning”: instead of imitating an action, it is given a goal and uses trial and error to achieve this goal. Based on the feedback it receives, it optimises its actions gradually until it solves the task. The hand can share its “knowledge” with others. Successful actions are available immediately to other similar hands, so mistakes are made only once.

One example of what the hand can do is to rotate a 12-sided cube so that a chosen side points upwards. It is taught a movement strategy in a virtual environment with the aid of a digital twin, created using data from a depth-sensing vision system and AI (artificial intelligence) algorithms.

To avoid having to pull the tubes that control the gripper fingers through a robot arm, Festo has developed a small, digitally controlled valve terminal that is mounted on the hand. It uses 24 proportional piezo valves to control the movements of the fingers precisely by varying flow rates and pressures. The hand can be connected quickly and easily and operated with only one tube each for supply air and exhaust air.

Festo's BionicSoftHand can learn to solve gripping and turning tasks using artificial intelligence

The BionicSoftHand has 12 degrees of freedom and can handle loads weighing up to 4kg. The hand incorporates 40 sensors (15 tactile force sensors and 10 inertial sensors in the fingers, 14 pressure sensors in the airflow plate, and an inertial sensor in the back of the hand).

Festo’s second nature-inspired development, the BionicSoftArm, is a lightweight, modular robotic arm which can be used for a wide range of applications, depending on how it is configured and the gripper used. It can work safely next to humans and eliminates the need for costly safety devices such as cages and light barriers.

The BionicSoftArm is a smaller, more versatile development of Festo's BionicMotionRobot, first shown in 2017. Its modular design can include up to seven 150mm-long pneumatic bellows segments and rotary drives, offering flexibility in terms of reach and mobility, and enabling the arm to work around obstacles in tight spaces. It is suitable for tasks traditionally handled by Scara robots, such as picking-and-placing.

The BionicSoftArm has seven degrees of freedom and can wind itself through tights spaces