Squishy fingers open up delicate robotics applications Thursday, 28 January 2016

A collaboration between a New York marine biologist and a Harvard roboticist has led to the development of "squishy fingers" which allow autonomous scientific vessels to collect fragile biological specimens without damaging the surrounding environment.

Harvard engineer Robert Wood says he was at a 2014 talk being given by David Gruber from Baruch College at the City University of New York featuring a video of specimens being collected by clunky robotic hands.

“They were using rigid Jaws of Life-type grippers designed for the oil and gas industry that were totally overpowered and were destroying things,” Wood said. “It immediately clicked that there was a soft robotics solution that may be viable.”

The two began to collaborate on on soft robotic grippers and successfully developed two types of grippers. In the process, they demonstrated a new fabrication technique that allows for the rapid creation of soft actuators.

One of their grippers was inspired by the coiling action of a boa constrictor and can access tight spaces and clutch small and irregular shaped objects. The other is a bellows-style model which features opposing pairs of bending actuators.

Wood said the biggest design challenge was a lack of precise specifications. They had no way of knowing the size, shape, or stiffness of the objects they would be sampling on the ocean floor.

To approximate likely specimens, they experimented with vegetables such as celery, radishes, carrots and bok choy.

To make it easy to modify and repair the grippers in the field, the team focussed on simple construction, inexpensive materials, and a modular design so they could try multiple configurations and make them in quantity. They have filed a patent application on the method for manufacturing the bellows-type soft actuators. Because it is scalable, it opens up a range of commercial, biomedical and industrial applications for this type of actuator.

The grippers were tested last year in the Red Sea on a large coral reef and the pair were happy with the performance.

Wood has a list of performance enhancements he hopes to pursue. He says current-generation ROVs rely exclusively on visual feedback – a live video feed from an onboard camera – but he’d like to add haptic feedback, applying his lab’s expertise in soft sensors to let an operator actually “feel” what the gripper is touching. He is also interested in experimenting with bilateral, rather than single-arm manipulation to achieve improved dexterity.

 

The squishy fingers delicately grip an organism in the Red Sea. Image: Harvard University