This article introduces a new approach to material handling, part sorting, and component assembly called “grasping”, in which a single reconfigurable grasper with embedded intelligence replaces an entire bank of unique, fixed-shape grippers and tool changers. We have to explore what is wrong with robotics today to appreciate the motivations that guided the design of Barrett’s grasper, the enormous potential for robotics in the future, and the dead-end legacy of gripper solutions.
Programmable flexibility is needed along the entire length of the robot, from its base, all the way to the target work piece for the benefits of a robotic solution to be realized. An arm of robot enables programmable flexibility from the base only up to the tool plate, a few centimeters short of the work piece target. But these last some centimeters of a robot have to adapt to the complexities of securing a new object on each robot cycle, capabilities where embedded intelligence and software excel. Look like the weakest link in a chain of serial, an inflexible gripper limits the productivity of the entire robot work cell.
Grippers have individually-customized, but fixed jaw shapes. The customization process of trial-and-error is design intensive, generally drives cost and schedule, and is difficult to scope in advance. Generally, each anticipated variation in orientation, shape, and robot approach angle requires another custom-but-fixed gripper, a place to store the additional gripper, and a mechanism to exchange grippers. An incremental improvement or unanticipated variation is simply not allowable.
For a flexibility high degree of tasks requiring such as handling variably shaped payloads presented in multiple orientations, a grasper is more secure, quicker to install, and more cost effective than an entire bank of custom-machined grippers with tool changers and storage racks.
Just one or two spare graspers can serve as emergency backups for several work cells, whereas one or two spare grippers are required for each gripper variation – potentially dozens per work cell for uninterrupted operation. And, it’s catastrophic if both backups of gripper fail in a gripper system, since it may be days before replacements can be identified, shipped, custom shaped from scratch, and physically replaced to bring the affected line back into operation. Since graspers are physically similar, they are always available in unlimited quantity, with all customization provided instantly in software.
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