Robot and Cobot Glossary

A

Accuracy

How close a robot's tool centre point (TCP) gets to a commanded position. A robot with ±2 mm accuracy will land within 2 mm of where you told it to go. Accuracy differs from repeatability: a robot can be highly repeatable (consistent) but inaccurate (consistently off-target). For most pick-and-place and machine tending tasks, repeatability matters more than absolute accuracy.

AGV (Automated Guided Vehicle)

A mobile robot that follows a fixed path defined by physical guides (magnetic tape, wire embedded in the floor, or laser reflectors). AGVs are reliable in predictable environments and generally less expensive than AMRs, but cannot reroute around obstacles. Contrast with AMR. See also: AMR vs AGV: Differences, Costs and Use Cases.

AMR (Autonomous Mobile Robot)

A mobile robot that builds a map of its environment and navigates autonomously, rerouting around obstacles in real time. AMRs cost more to deploy than AGVs but require no floor modification and can adapt to changing facility layouts. See AMR vs AGV for a full comparison.

Articulated robot

A robot arm with two or more rotary joints (axes). Six-axis articulated robots are the most common type in manufacturing, offering near-human arm flexibility. The joints allow reach into confined spaces and operation at many angles, making them suitable for welding, machine tending, assembly and material handling.

C

Cartesian robot (Gantry robot)

A robot that moves along three linear axes (X, Y, Z). Cartesian robots are simple to program, highly accurate over large working areas, and well-suited to dispensing, pick-and-place, and CNC loading where the workspace is rectangular. They cannot reach around obstacles or work at odd angles. See Cartesian Robot Guide.

Cobot (Collaborative robot)

A robot designed to work in proximity to human operators, incorporating safety features (force/torque sensing, rounded edges, speed and force limits) that allow it to stop or slow when contact is detected. ISO/TS 15066 defines four collaborative modes: safety-rated monitored stop, hand guiding, speed and separation monitoring, and power and force limiting. Not all cobot deployments are guarding-free — a risk assessment is always required. See Collaborative Robots Guide.

Cycle time

The time from the start of one part operation to the start of the next identical operation. For a machine tending application, cycle time includes robot move time, gripper open/close, door operation, machine clamping, machining time, and any idle waits. Cycle time determines throughput: parts per hour = 3,600 ÷ cycle time in seconds.

D

Delta robot

A parallel-linkage robot with three arms connected to a common end-effector platform. Delta robots operate at very high speeds (up to 150–300 picks per minute) over a shallow, dome-shaped workspace, making them ideal for high-speed pick-and-place of small, lightweight parts in food, pharmaceutical and electronics applications. See Delta Robot Guide.

Duty cycle

The percentage of time a robot is actively performing useful work versus waiting or idle within a given period. A robot with a 15-second cycle time running on a 20-second part cycle has a 75% duty cycle. Higher duty cycles improve ROI but may require additional maintenance intervals.

E

EOAT (End-of-Arm Tooling)

Any device mounted at the end of a robot arm that interacts with parts or the environment — grippers, suction cups, welding torches, dispensing nozzles, sensors, cameras. EOAT is often the most application-specific and failure-prone component of a robot cell; budget 15–30% of total system cost for a well-engineered EOAT. See End-of-Arm Tooling Guide.

F

Force/torque sensing

A sensor, usually mounted between the robot flange and the EOAT, that measures forces and torques in six degrees of freedom. Used in collaborative robots for collision detection (stopping when contact force exceeds a threshold), and in assembly applications for force-controlled insertion (pressing a bearing into a housing until a target force is reached).

I

ISO 10218

The international standard for the safety of industrial robots. Part 1 covers the robot itself (manufacturer requirements); Part 2 covers robot systems and integration (integrator and end-user requirements). In the US, ANSI/RIA R15.06 adopts ISO 10218 with supplementary requirements. A risk assessment per ISO 10218-2 is required for every robot installation. See ISO/TS 15066 Explained.

ISO/TS 15066

A technical specification supplementing ISO 10218 that defines requirements for collaborative robot systems. It specifies the four collaborative modes (safety-rated monitored stop, hand guiding, speed and separation monitoring, power and force limiting) and provides biomechanical limits on allowable contact forces for each body region. See ISO/TS 15066 Explained Simply.

J

Jogging (Teach mode)

Manually moving the robot through its workspace using a teach pendant or tablet to record waypoints. Online programming by jogging is simple but slow for complex paths. Compare with offline programming, where paths are generated in simulation software and uploaded to the controller.

Joint

A rotary or linear actuator at each segment of the robot arm. A six-axis robot has six rotary joints (called J1–J6 or axes 1–6). The number and arrangement of joints determines the robot's workspace, range of motion and the configurations it can reach.

L

Lights-out machining

Running a CNC machine unattended, usually overnight or on weekends, with a robot or automation system loading and unloading parts. True lights-out requires sufficient raw material in the input staging area, automatic chip management, in-process gauging, and a reliable tool-change or tool-monitoring system. See Lights-Out Machining With a Cobot.

M

Machine tending

Using a robot to load raw stock into a CNC machine, press, injection moulder or other process machine, and to unload finished or semi-finished parts. Machine tending is among the highest-ROI cobot applications for small manufacturers: it replaces repetitive operator labour during machining cycles. See Machine Tending Guide.

Mobile manipulator

A robot arm mounted on an AMR or AGV platform, combining mobility (moving between workstations) with manipulation (picking, placing, assembling). Mobile manipulators are more complex and expensive than fixed cobots but allow a single robot to serve multiple CNC machines or assembly stations. See Mobile Manipulator Robots.

P

Payload

The maximum mass a robot can carry at its wrist, including the EOAT and any tooling. Rated payload is typically the maximum at full extension; actual usable payload depends on arm reach and orientation. Always subtract gripper mass from rated payload to determine available part-lifting capacity. Cobots range from about 3 kg (UR3e, Fanuc CRX-5iA) to 35 kg (UR20, Fanuc CRX-25iA).

Power and force limiting (PFL)

One of the four collaborative modes defined in ISO/TS 15066. The robot is intrinsically designed or externally safeguarded so that contact forces do not exceed the biomechanical limits specified in the standard. Most cobots use PFL as their primary collaborative operating mode. PFL does not automatically mean a guarding-free installation — the risk assessment must still confirm that force limits are met at all body regions.

R

Reach (Working range)

The maximum distance from the robot base to the tool centre point (TCP) at full arm extension. Reach determines what workspace the robot can service. Common cobot reaches: 500 mm (UR3e) to 1,750 mm (UR20, Fanuc CRX-25iA). Note that rated reach is at full extension; the robot cannot realistically carry full payload at maximum reach.

Repeatability

How consistently a robot returns to a previously taught position across multiple cycles. Expressed as ± a distance in mm (or μm for precision robots). Cobots typically achieve ±0.02–0.1 mm; industrial robots ±0.01–0.05 mm. Repeatability is not the same as accuracy: repeatability measures cycle-to-cycle variation at a taught point, not how close that point is to an absolute coordinate. For most manufacturing tasks, repeatability is the critical specification.

ROI (Return on Investment)

In robot deployments, ROI is typically expressed as payback period: Total Installed Cost ÷ Annual Labour Savings. Total installed cost must include robot hardware, EOAT, guarding, integration, programming, training, facilities modifications and spares — not just the robot purchase price. A full worked example is at Robot ROI Calculation: A Worked Example.

S

SCARA robot

Selective Compliance Assembly Robot Arm. A robot with two horizontal rotary joints and one vertical linear joint, forming a horizontally rigid, vertically compliant arm. SCARA robots are very fast at horizontal pick-and-place (40–100 picks per minute), compact, and accurate for assembly and small-parts insertion. They cannot reach under or around obstacles. See SCARA Robot Guide.

Speed and separation monitoring (SSM)

A collaborative mode (ISO/TS 15066) in which the robot continuously monitors its distance from a detected human. When the human approaches within a defined zone, the robot slows; when within a minimum protective distance, the robot stops. Requires a safety-rated area scanner or 3D camera. Common in cells where operators need periodic access but do not work alongside the robot continuously.

T

TCP (Tool Centre Point)

The reference point at the tip of the robot's end-effector — the point whose position and orientation the robot controller tracks and controls. Setting the correct TCP offset (the distance and rotation from the robot flange to the actual working point of the tool) is required for accurate path execution and is one of the first commissioning steps.

W

Workspace (Work envelope)

The three-dimensional volume reachable by the robot's TCP. For articulated robots the workspace is roughly spherical with a dead zone directly above the base. The usable workspace is smaller than the theoretical maximum because certain near-singular configurations are excluded, and payload capacity drops toward the extremes of reach.