A new robotic end-effector developed by researchers at General Robotics Lab enables manipulation of objects through coordinated linear movements alone, eliminating the need for complex multi-joint articulation. The Cartesian Hand, a 7-degree-of-freedom device composed entirely of prismatic joints, achieves dexterous tasks by combining independent grasping with relative motion between object components using only sliding actions.

The system employs two stacked parallel grippers that independently hold different sections of an object, while four translating fingertips create relative displacement between these held parts. This configuration allows manipulation to be executed through a small set of linear motion primitives—such as point push/pull, horizontal or vertical open/close, pivot/translate, twist, and dual grasp—each derived from simple combinations of joint movements.

Because all seven joints move along fixed axes, the hand maintains consistent kinematic behavior regardless of configuration. Each fingertip position corresponds to a linear function of the joint states, resulting in a constant, full-rank Jacobian matrix that simplifies control. The design supports configuration-independent operation, meaning the same motion primitives function identically across all hand positions.

The researchers demonstrated the hand’s capability through 35 test objects spanning laboratory, manufacturing, and household domains. Tasks included cap opening and closing, pipetting, pumping, screwdriving, trigger actuation, and in-grasp reorientation. The same procedural framework transferred directly from a fixed-base robotic arm to a humanoid platform, enabling bimanual laboratory manipulation using two Cartesian Hands.

Mechanically, the device features fingertip travel of 65 millimeters, with independent travel of 52 millimeters for each gripper and separation mechanism. Joint speed reaches approximately 60 millimeters per second, and the system can statically hold up to 2 kilograms per gripper. With a mass of 850 grams and dimensions of approximately 166 by 100 by 76 millimeters, the structure is fabricated from 3D-printed PLA or nylon, targeting a production cost near $500.

The work presents a novel approach to in-hand manipulation by embedding relative motion capabilities directly into the end-effector architecture. Rather than relying on external tools or multi-fingered articulated hands, the Cartesian Hand leverages coordinated linear motions to replicate complex manipulation tasks. This architecture suggests a pathway toward simpler, more robust robotic manipulators capable of handling structured mechanical interfaces such as threads, pivots, and triggers without requiring external fixtures or additional actuators.

The findings were published as a preprint on September 22, 2026, with associated code and research materials made publicly available through arXiv and GitHub.