Approach by BASF and the University of California – compressed air replaces the usual electronics
Researchers at the University of California (https://ucsd.edu) and German chemical giant BASF (https://www.basf.com/global/de.html) are turning to pneumatics for robotic grippers in the future. “A series of valves allows the gripper to grab when it touches an object and also release it at the right time,” says Yichen Zhai, a postdoctoral researcher in the Bioinspired Robotics and Design Lab. All it takes to release the grip is to turn the gripper horizontally.
Ready for use without rework
The gripper is manufactured using additive manufacturing, i.e. 3D printing, with a plastic powder developed by the Ludwigshafen-based company. Immediately after completion and connection to a source of compressed air, it is ready for use. Such a soft gripper enables robots to interact safely with humans and delicate objects. It can be used in the assembly of mechanical and electrical components and in the food industry for handling fruits and vegetables, they say. The only energy source is a bottle full of compressed air, it says.
There are often imperfections in 3D printing. The American-German team avoids this by guiding the nozzle from which the powder flows through the whole process without settling. “It’s like drawing a complete picture without once taking the pencil off the page,” says Michael T. Tolley, associate professor of mechanics and aeronautics at the university’s engineering school.
Wafer-thin wall thicknesses feasible
The new process also makes it possible to print thin walls down to 0.5 millimetres thick. Thinner walls make for better deformability, which allows the gripper to grip more gently. The theory behind this is called the “Eulerian path”. This connects several objects without touching one twice. “When we followed these rules, we were able to print consistently functional pneumatic soft robots with embedded valves,” says Tolley.