What could be more natural then than equipping robots in collaborative workspaces with a gripper that is modelled after this tool that solves various tasks by learning through artificial intelligence? Festo has designed just such a pneumatic robot hand, BionicSoftHand, which when combined with its BionicSoftArm, a pneumatic lightweight robot, is said to be suitable for human-robot collaboration.
The BionicSoftHand is pneumatically operated so that it can interact safely and directly with people. Instead of bones, its fingers consist of flexible bellows structures with air chambers.
The bellows are enclosed in the fingers by a textile coat knitted from both elastic and high-strength threads. With the help of the textile, it is possible to determine exactly where the structure expands and generates power, and where it is prevented from expanding. This makes it light, flexible, adaptable and sensitive, yet capable of exerting strong forces.
The learning methods of machines are comparable to those of humans: Either in a positive or a negative way – they require a feedback following their actions in order to classify and learn from them. BionicSoftHand uses a method called reinforcement learning.
This means that, instead of imitating a specific action, the hand is simply given a goal. It uses the trial and error method, to achieve this goal. Based on received feedback, it gradually optimises its actions until the task is finally solved successfully.
For example, the BionicSoftHand can rotate a 12-sided cube so that a previously defined side points upwards. The necessary movement strategy is taught in a virtual environment with the aid of a digital twin, which is created with the help of data from a depth-sensing camera via computer vision and artificial intelligence algorithms.
In order to keep the effort of tubing the BionicSoftHand as low as possible, the developers have specially designed a small, digitally controlled valve terminal, which is mounted directly on the hand. This means that the tubes for controlling the gripper fingers do not have to be pulled through the entire robot arm. Thus, the BionicSoftHand can be quickly and easily connected and operated with only one tube each for supply air and exhaust air. With the proportional piezo valves used, the movements of the fingers can be precisely controlled.
One arm, many variations
The strict separation between the manual work of the factory worker and the automated actions of the robot is being increasingly set aside. Their work ranges are overlapping and merging into a collaborative working space. In this way, human and machine will be able to simultaneously work together on the same workpiece or component in the future – without having to be shielded from each other for safety reasons.
The BionicSoftArm is a compact development of Festo’s BionicMotionRobot, whose range of applications has been significantly expanded. This is made possible by its modular design: It can be combined with up to seven pneumatic bellows segments and rotary drives. This guarantees maximum flexibility in terms of reach and mobility, enabling it to work around obstacles even in the tightest of spaces. At the same time, it is completely flexible and can work safely with people. Direct human-robot collaboration is possible with the BionicSoftArm, as well as its use in classic SCARA applications, such as pick-and-place tasks.
Flexible application possibilities
The modular robot arm can be used for a wide variety of applications, depending on the design and mounted gripper. Thanks to its flexible kinematics, the BionicSoftArm can interact directly and safely with humans. At the same time, the kinematics make it easier for it to adapt to different tasks at various locations in production environments: the elimination of costly safety devices such as cages and light barriers shortens conversion times and thus enables flexible use – completely in accordance with adaptive and economical production
Nature teaches what optimal drive systems for certain swimming movements should look like.
To move forward, the marine planarian, a type of flatworm, and cuttlefish create a continuous wave with their fins, which advances along their entire length. For the BionicFinWave, the bionics team was inspired by this undulating fin movement. The undulation pushes the water backwards, creating a forward thrust. This principle allows the BionicFinWave to manoeuvre forwards or backwards through an acrylic tube system.
Its two side fins are completely cast out of silicone and do not require struts or other supporting elements. The two fins are attached to the left and right of nine small lever arms, which in turn are powered by two servo motors. Two adjacent crankshafts transmit the force to the levers so that the two fins can be moved individually to generate different shaft patterns. They are particularly suitable for slow and precise locomotion and whirl up less water than, for example, a screw drive. A cardan joint is located between each lever segment to ensure that the crankshafts are flexible. For this purpose, the crankshafts including the joints and the connecting rod are made of plastic in one piece using a 3D printing process.
The remaining elements in the BionicFinWave’s body are also 3D printed, enabling complex geometries such as cavities that act as flotation units. At the same time, the entire control and regulation technology is watertight, safely installed and synchronised in a very tight space.
With these bionic technologies, Festo’s Bionic Learning Network is undertaking future work with autonomous robots and new drivetrain technologies in liquid media. The company believes that further development of concepts like the BionicFinWave are possible for tasks such as inspections, measurements or data collections – for example for water and wastewater technology or other areas of the process industry.