Handling Delicate Matters

The emergence of soft robotics represents a major advancement in the field of robotics, particularly when it comes to handling and manipulating delicate objects that would be vulnerable to damage by traditional, rigid robots. Soft robots are constructed with flexible materials and compliant structures, enabling them to interact with objects in a more gentle and adaptable manner. This feature is particularly advantageous in industries such as food handling, medical applications, and delicate assembly processes, where the integrity of objects is of great importance.

However, there is a trade-off in leveraging soft robotics for delicate object manipulation. While the gentleness of soft robots is their strength, it also becomes their limitation in terms of power and precision. Traditional, rigid robots are typically capable of exerting more force and achieving higher precision in their movements. This lack of strength and precision in soft robots may limit their applications in tasks that demand significant force, such as heavy lifting or industrial assembly with tight tolerances.

To address this trade-off, researchers and engineers are continuously exploring innovative solutions. Some approaches involve hybrid systems that combine the benefits of both soft and rigid robotics, creating robots with variable stiffness that can adapt their capabilities to the specific task at hand. Additionally, advancements in control algorithms and materials are being pursued to enhance the strength and precision of soft robots while maintaining their delicate handling characteristics.

But existing systems have yet to fully address the problem of building soft robotic grippers that can operate with precision and handle heavy objects. Promising work recently reported on by a team at North Carolina State University may help to move the ball forward significantly, however. They have developed a robotic gripping device that is gentle enough to pick up even a droplet of water, yet it can also pick up items weighing in excess of 14 pounds. And as for precision, the gripper can easily get a handle on microfibers that are 40 times thinner than a typical human hair.

The idea for the researchers gripper comes from kirigami, which is related to origami, the Japanese art of folding paper, in which paper is both folded and cut to form three-dimensional shapes. The grippers were laser cut from sheets of polyethylene terephthalate into a design that maximizes strength. This design resulted from a long string of previous experiments conducted by this team using similar techniques. The actuation of the grippers, that allows them to hold onto objects, was inspired by the nastic curves in tendril plants.

The strength and gentleness of the gripper result from a unique design that distributes force throughout the entire device while it is in operation. This gives the gripper a record-breaking payload-to-weight ratio of about 16,000 — 2.5 times greater than the previous record. And given the precision and genetless afforded to the gripper by its structure, it can enable many new use cases that were previously impractical.

In one particularly interesting demonstration, the gripper was integrated with a myoelectric prosthesis. This initial work shows the promise of this device in one day replacing the delicacy and strength of the human hand. The team also sees applications for their gripper in handling food or biomedical materials, or in presently difficult to perform tasks like zipping zippers or picking up coins.

It was noted that the gripper is both scale- and material-independent, so the device could easily scale up to handle very large jobs, or down to handle tiny jobs. The researchers are presently investigating alternate material types to optimize durability and strength.