Robot Catalogue Speed Fields: Joint Rotation and Tool Motion Are Different Measurements

A robot catalogue may show a speed value in degrees per second and another in metres per second. Both numbers describe motion, but they do not measure the same thing. A database that puts them into one generic “speed” field can mislead readers comparing equipment. The record needs the measured quantity, unit, reference point and conditions as well as the value.

Joint speed and tool speed answer different questions

Joint speed describes rotation at a particular robot joint. Tool-center-point (TCP) speed describes motion of a defined point associated with the tool. The latter may include linear and rotational components depending on the interface and definition used. A catalogue should not compare a joint's angular speed directly with a TCP's linear speed merely because both are labelled “maximum speed.”

Universal Robots' UR10e technical specification separately identifies joint ranges, joint speeds and maximum TCP speed. Those values describe the specified model and configuration. They are useful evidence of distinct fields, not a set of values to apply to every robot in a catalogue.

Make the unit and axis explicit

For each joint-speed entry, record which joint it describes and the unit used by the source. For a TCP value, record whether the figure concerns linear speed, angular speed or a composite interface value. If a supplier gives a range or an approximation, preserve that qualifier rather than presenting an invented exact number.

A unit conversion can make two figures easier to read, but it cannot turn a joint-speed limit into a tool-speed limit. Degrees per second and radians per second both describe angular speed; metres per second describes linear speed. If a record includes a converted value, retain the original value and unit as well as the conversion method so that a reviewer can check it.

Distinguish a specification from a live reading

A maximum in a product sheet and a value reported by a running controller have different purposes. Universal Robots' real-time interface documentation lists an actual TCP-speed field as part of its interface data. A live reading represents an observation at a particular time and configuration; it should not overwrite a model's published specification in a product database.

When storing operational data, capture the timestamp, device identity, interface version and coordinate information required to interpret it. When storing a catalogue specification, retain the source document, revision and applicable model. Do not assume a reading collected on one machine represents every unit of that model.

Conditions matter to comparisons

Published maximums may be subject to operating conditions, configuration, limits or qualifications. The UR10e specification, for example, notes reduced speed and performance at ambient temperatures above a stated threshold. A database should preserve such conditions alongside the value. It should not imply that a catalogue maximum is achieved throughout every trajectory or under every load.

Consider a fictional comparison between two robots: one listing provides a maximum joint speed for an axis, while the other provides an approximate TCP linear speed. The responsible response is to mark the fields as different and request comparable data. Ranking the robots by the larger number would not be a meaningful comparison.

Use a catalogue schema that can be audited

A practical record can include the quantity name, axis or reference point, value, unit, conditions, source URL, document revision and date checked. Separate missing data from zero, and identify whether a number was taken directly from the source or calculated by the catalogue operator. If the supplier changes a specification, retain the previous record and the date of the update.

Catalogues should also distinguish model-level capabilities from the configuration and safe operating limits of an installed system. The actual tool, payload, trajectory and application can affect what motion is appropriate. A product page is not a safety assessment or a validated cycle-time guarantee.

Questions for a buyer or integrator

Before selecting equipment, ask the manufacturer which values apply to the intended model and controller, what the measurement conditions are and whether the proposed application has additional limits. For a cycle-time claim, request evidence for the actual motion, tool and load instead of extrapolating from a single maximum-speed number.

If the source uses a chart instead of a table, document the chart's axes and conditions before entering an estimated value. Mark the value as estimated if it was read from a graph. Where the scale is unclear or the source is no longer available, leave the field unresolved and ask the manufacturer for clarification.

Related database topics include product aliases and model identity and gripper weight, payload and force. Browse the robot catalogue section for additional context. This article explains data fields and does not recommend operating speeds.