This Gripper Is on a Roll — Literally
UC San Diego engineers turned measuring tape into a robotic gripper that’s lightweight, flexible, and gentle enough to pick tomatoes.
Some design problems are pretty well solved, like the zipper on clothing or the design of a standard light switch. Sure, there is some amount of variation in these designs, but the core functionality and user experience have become fairly consistent. But then there are the more experimental areas where things have not yet been worked out so well. Robotics has many such areas — consider the gripper, for instance. Issues like excessive bulk, high costs, and difficulties with grasping delicate objects plague existing systems and have led to a proliferation of experimental designs.
Engineers at the University of California San Diego have taken on these issues by developing a new type of gripper with a very novel design. Inspired by the childhood (and sometimes adulthood) pastime of seeing how far a tape measure can extend before bending, the team created a low-cost, flexible robotic gripper made from measuring tape. Called GRIP-tape, the device uses the material’s unique combination of strength, flexibility, and springiness to grab objects gently yet effectively.
The design features two "fingers," each composed of a spool holding two rolls of measuring tape bound together for added rigidity. These spools are compact when retracted but can be extended into triangular-shaped appendages that reach out to grab objects. Four small motors control the motion of each triangle section, enabling the gripper to lengthen or retract the fingers independently.
Unlike traditional grippers that require bulky mechanisms to achieve a wide reach, GRIP-tape’s design is both space-efficient and lightweight. When not in use, the gripper folds neatly into a compact form, ideal for space-constrained environments such as agricultural fields, spacecraft, or deep-sea operations.
The unique design allows for advanced manipulation capabilities — such as rotating objects or conveying multiple items — by controlling how each finger rotates relative to the other. Furthermore, the measuring tape’s steel structure is robust enough for repeated use but soft enough to handle delicate fruits like tomatoes or lemons without bruising them.
Because the tape can move like a conveyor belt, it can transport objects across its surface and deposit them elsewhere. In a series of trials, the gripper successfully lifted and moved large, irregularly shaped fruits such as oranges and entire tomato vines. By rotating the fingers in opposing directions, it was shown that the gripper can even gently pick fruit by twisting its stem.
By rethinking the gripper’s form and function through the lens of a simple tool like a tape measure, the researchers may have opened the door to a new generation of lightweight, adaptable robotic manipulators. It has to make you wonder — what other everyday objects around us could transform the world of robotics?
