Grasping via entanglement

Abstract We present a grasping strategy for complex shapes via the collective entanglement of and by an array of actuated filaments. The basic unit of this array is a slender hollow elastomeric filament that is pneumatically actuated to form a highly curved structure. The multiple self and mutual contact interactions between the filaments and the object create a randomly tangled spatial assemblage that enables a soft conformable grasp. We realize this using a gripper enabled by a new fabrication method to create inexpensive and modular arrays of fluidically actuated elastomeric filaments. We demonstrate that a collective of highly compliant filamentous actuators is capable of a soft, adaptable grasp across a range of loads that vary in size, shape, and geometric and topological complexity without any feedback. A theoretical framework for the collective mechanics of filaments in contact with complex objects allows us to explain our experimental findings, while a phase diagram characterizes the design space in terms of the properties of the gripper and the target. Overall, our grasping approach adapts to the mechanical, geometric, and topological complexity of target objects via an uncontrolled, spatially distributed, and heterogeneous scheme without perception or planning, in sharp contrast with current deterministic feedback-driven robotic grasping methods.