How do you determine a robot’s payload and reach ratings?

• A. Payload is the maximum mass/force the robot can handle with specified accuracy; reach is the maximum distance from base to end effector; both define workspace
• B. Payload is the maximum speed; Reach is maximum rotation
• C. Payload equals arm length; Reach equals payload mass
• D. Both are only dependent on gripper type

Answer: (A)

Payload and reach describe what a robot can handle and how far its arm can extend. Payload is the maximum mass or force the robot can manage while meeting the required accuracy or repeatability. This limit comes from the motor torque, gear train, structural stiffness, and the control system, and it often depends on the pose: lifting payload when the arm is extended against gravity or during rapid motion reduces the usable payload. In practice, the payload rating is specified for a given configuration and accuracy requirement, so it isn’t a single universal number.

Reach is the maximum distance from the base to the end effector, determined by the lengths of the links and the angles of the joints that produce the greatest straight-line extension. It is influenced by joint limits and potential obstructions in the environment, so the actual reachable envelope is shaped by the robot’s geometry and its operating constraints.

Together, payload and reach define the robot’s usable workspace and performance envelope, telling you what tasks it can physically perform and what end-effectors it can realistically handle. The other ideas—speed, simple angular motion, a direct equivalence to arm length, or dependence solely on the gripper—don’t capture how payload and reach characterize load capability under accuracy requirements and the spatial reach of the arm.