A simple robotic gripper created by engineers at the Massachusetts Institute of Technology (MIT) can adjust its hold using the environment. The team's model predicts the force with which a gripper must push against surrounding fixtures in order to adjust its grasp. The new approach allows existing medical robots to perform more complex maneuvers.

Providing such extrinsic flexibility could allow a surgical robot, for example, to push a scalpel against an operating table to adjust its grip.

The researchers developed a model that describes the forceful interaction between a gripper, a grasped object, and different types of external fixtures such as corners, edges, or surfaces. To predict how an object may move as a gripper pushes it against a given fixture, the researchers designed the model to take into account various factors, including the frictional forces between the gripper and the object, and between the object and the environment, as well as the object’s mass, inertia, and shape.

In its current iteration, the model predicts the force a gripper must exert, on the object and the environment, to maneuver the object to a desired orientation.

“Exploiting the environment is, and will be, important for robots and the research community,” said Alberto Rodriguez, an assistant professor of mechanical engineering. “Any applications where you have limitations in terms of payload or cost or complexity, areas like manufacturing, or surgery, or field operations, or even space exploration — whenever you have a gripper that is not dexterous like a human hand, this [method] gives you some of that dexterity.”