Robotics Terminology & Engineering Glossary
Standardized technical definitions for articulated manipulators, mobile AMRs, legged robotics, and medical telemanipulators. All definitions adhere to international standards (ISO 9283, ISO 10218, ISO 3691-4, IEC 60601) and peer-reviewed mechanical literature.
Kinematics & Actuation
- Degrees of Freedom (DOF)
- The number of independent kinematic parameters that define the configuration or spatial pose of a mechanical system. A rigid body in 3D Euclidean space possesses 6 DOF (3 Cartesian translations: X, Y, Z; and 3 Euler rotations: roll, pitch, yaw). Articulated arms like the UR10e feature 6 DOF, while redundant research manipulators like the Franka Research 3 incorporate 7 DOF to allow null-space obstacle avoidance.
- Pose Repeatability vs. Absolute Accuracy (ISO 9283)
- Under ISO 9283, repeatability defines the closeness of agreement among position and orientation coordinates attained by a robot after repeatedly executing the exact same trajectory under identical thermal and load conditions (e.g., ±0.05 mm on the UR10e). Absolute accuracy measures the spatial error between a commanded coordinate in the world frame and the physical position achieved; accuracy is consistently lower than repeatability due to gearbox compliance, manufacturing tolerances, and link thermal expansion.
- Center-of-Gravity (CoG) Offset
- The radial and axial vector distance between a robot's mechanical tool mounting flange and the combined center of mass of the installed end-effector plus payload. Outward CoG offsets amplify static gravitational bending moments and dynamic rotational inertia, derating allowable scale mass below nominal datasheet capacity. Sizing should be performed with our Cobot Payload Offset Calculator and reviewed in our CoG Engineering Guide.
- Remote Center of Motion (RCM)
- A kinematic invariant constraint where an articulated instrument shaft rotates exclusively about a stationary 3D spatial pivot point located distally from the robot joints. RCM is mandatory in minimally invasive laparoscopic surgery (Intuitive da Vinci 5) to prevent tearing patient abdominal incision walls during instrument articulation. See our Surgical Robotics Guide.
Mobile Autonomy & SLAM
- Autonomous Mobile Robot (AMR) vs. AGV
- Automated Guided Vehicles (AGVs) navigate along fixed physical lines (magnetic tape, optical QR grids) and halt when confronted with obstructions. AMRs (such as the Locus Origin) use onboard LiDAR and visual SLAM to build dynamic 2D/3D occupancy maps, recalculating collision-free detour trajectories without floor infrastructure. Review our AMR vs AGV Selection Guide.
- Simultaneous Localization and Mapping (SLAM)
- A computational problem where a mobile platform constructs or updates a spatial map of an unknown environment while simultaneously estimating its own trajectory within that map. Techniques include 2D LiDAR SLAM (Cartographer, Gmapping), 3D LiDAR Odometry (LIO-SAM), and Visual SLAM (ORB-SLAM3) deployed on platforms like the Unitree Go2 and TurtleBot 4.
- Real-Time Kinematic (RTK) Positioning
- A satellite navigation technique that uses carrier-phase measurements of GPS/Galileo/BeiDou signals combined with real-time base station corrections to achieve horizontal positioning accuracies within 1 to 2 centimeters. Essential for heavy autonomous agricultural spraying platforms like the DJI Agras T50 to ensure zero swath overlap.
- Direct Time-of-Flight (dToF) LiDAR
- An optical distance-measurement technique that emits picosecond laser pulses and calculates distance directly by timing the reflected photons via Single-Photon Avalanche Diodes (SPADs). Delivers high ambient light immunity compared to phase-shift methods, utilized in domestic cleaners like the Roomba Combo j9+.
Control Systems & Physics
- Specific Cost of Transport (COT)
- A dimensionless metric quantifying energetic efficiency in terrestrial locomotion: $\text{COT} = P_{\text{avg}} / (m_{\text{total}} \cdot g \cdot v_{\text{transit}})$. Wheeled AMRs achieve exceptional efficiency with COT values of 0.05 to 0.12, whereas dynamic bipedal humanoids (Unitree G1, Agility Digit) consume 10x more energy with COT values of 0.8 to 1.8. Read our Humanoid vs AMR Transport Study.
- Real-Time Control Loop Jitter (PREEMPT_RT)
- The temporal variation in the execution interval of a digital control callback. At high update frequencies (such as the 1 kHz Franka Control Interface), timing latency must stay under $50\,\mu\text{s}$ using real-time Linux kernels. Jitter spikes introduce unstable torque derivatives that trip emergency watchdog interlocks. Read our Research Platforms Guide.
- Active Dorsal Hotel Load
- The steady-state baseline electrical power consumed by auxiliary payload sensors, edge GPUs (e.g. NVIDIA Jetson AGX Orin), radios, and depth cameras independent of motor locomotion. On quadrupeds like Boston Dynamics Spot, an 80W–150W dorsal hotel load reduces battery runtime from 90 minutes down to 45–60 minutes. Read our Quadruped Runtime Field Report.
- Rotor Wake Downwash Velocity ($v_{\text{wake}}$)
- The vertical induced airflow velocity directly underneath a multirotor propeller disk: $v_{\text{wake}} = \sqrt{T / (2 \cdot \rho \cdot A_{\text{disk}})}$. On 100+ kg agricultural UAS, downwash exceeding 12 m/s drives chemical droplets into dense crop canopies while requiring careful droplet size management to prevent drift. Read our Drone Swath Physics Study.
Safety Standards & Compliance
- ISO/TS 15066:2016 (Collaborative Robots)
- Technical specification establishing biomechanical pressure and force pain-sensitivity thresholds for human body regions in shared collaborative workspaces. Sizing max TCP speed (typically 0.25–0.50 m/s) and selecting rounded tool shapes are mandatory to satisfy Power and Force Limiting (PFL) compliance.
- ISO 3691-4:2023 (Driverless Industrial Trucks)
- International safety standard for AGVs and AMRs governing optical protective fields, automatic speed zone adaptation, mechanical bumper travel margins, and emergency stop deceleration on industrial floors.
- Ingress Protection (IP Codes: IEC 60529)
- Two-digit classification rating enclosure protection against solid particulate ingress (first digit: 0–6) and water ingress (second digit: 0–9). For example, IP54 protects against limited dust and water splashing (Spot), while IP67 certifies complete dust-tight sealing and immersion in water up to 1 meter depth.
- FDA 510(k) Premarket Clearance
- A regulatory demonstration to the US Food and Drug Administration that a commercial medical device is substantially equivalent in safety and efficacy to a legally marketed predicate device. Mandatory for surgical robotics platforms before commercial hospital deployment.
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