How is a cobot speed limit calculated?

Compute sqrt(2 × energy ÷ effective mass) for the physically meaningful PFL speed, then apply the safety multiplier. With 490 mJ and 4 kg, sqrt(2 × 0.49 J ÷ 4 kg) ≈ 495 mm/sec, and the 0.8 margin brings the indicative limit to about 396 mm/sec.

What is effective mass at the TCP?

It is the robot's reflected mass at the tool point in the direction of motion, combining payload and the contributing link inertia, not just the gripper weight. A higher effective mass means a lower safe speed because the same impact carries more energy.

Is this the same as the certified safe speed?

No. This is an indicative starting point only. Certified speed comes from measuring transient and quasi-static contact force and pressure with an instrumented gauge against the body-region limits in ISO/TS 15066, then locking the speed in the safety controller.

Why apply a safety margin multiplier?

Because the energy model idealizes the impact and ignores edge geometry, soft tissue variation, and tool stiffness. The 0.8 factor pulls the raw 495 mm/sec PFL speed down to about 396 mm/sec to leave headroom before validation.

What is a typical cobot collaborative speed?

Many transient-contact scenarios land in the 100 to 250 mm/sec range, and quasi-static (clamping) contacts force much lower speeds. The exact number always depends on the contacted body region and tool geometry, which is why measurement is mandatory.

Does a lower payload always allow higher speed?

Generally yes, because effective mass drops and the safe energy is reached at a higher velocity. But sharp tooling reduces the allowable pressure and can cap speed well below what the energy-only estimate permits.

Robotics & Automation calculator

Collaborative Robot Speed Limit Calculator

A collaborative robot speed limit is the maximum tool-center-point velocity that keeps a transient (free-space impact) contact below the energy a body region can safely absorb under ISO/TS 15066. Robot integrators, automation engineers, and safety officers use this as a first-pass estimate when laying out a cobot workcell before formal force-and-pressure measurement. It matters because cobots earn their value by running without fencing, and that permission depends entirely on keeping contact energy within biomechanical limits. An energy-and-mass estimate gets you into the right speed range so the pendant validation that follows confirms rather than surprises.

What this calculator does

Estimate a power-and-force limited cobot TCP speed by relating allowable transient transfer energy to effective TCP mass, with a safety margin per ISO/TS 15066.
Use it when running a cobot in power-and-force-limited mode and you need an indicative TCP speed limit per body region before pendant teach and validation.
It derives an indicative TCP speed from allowable transient transfer energy divided by effective mass, taking the square root and applying a safety-margin multiplier to give a starting speed in mm/sec.

Formula used

Unmargined PFL speed = sqrt(2 × transfer energy ÷ effective mass), reported in mm/sec
Cobot TCP speed limit (indicative) = PFL speed x safety margin multiplier, then validate by pendant test

Inputs explained

Allowable transient transfer energy: Use ISO/TS 15066 Annex A allowable transient energy in mJ for the body region in contact (e.g., back of hand 490 mJ).
Effective mass at the TCP: Use effective mass at the TCP from the cobot vendor data for the planned posture and EOAT, not the robot total mass.
Safety margin multiplier: Use a margin (0.7 to 0.9) on the result to cover posture variance and pendant validation. Confirm with the cobot pendant test under ISO/TS 15066.

How to use the result

Use it during early workcell layout to set a candidate cobot speed for a given contact scenario before you run formal force, pressure, and energy measurements.
It is indicative only. Real safety acceptance requires measured transient and quasi-static force and pressure against the applicable body-region limits; geometry, sharp edges, and clamping (quasi-static) contact can require far lower speeds than this energy estimate suggests.

Current U.S. benchmarks

Global copper trades at $13,543 per tonne (IMF via FRED, Jul 2026), up 38.6% in a year, and U.S. industrial electricity averages 8.71 cents per kWh. Both feed electrified-hardware unit economics.

Common questions

How is a cobot speed limit calculated? Compute sqrt(2 × energy ÷ effective mass) for the physically meaningful PFL speed, then apply the safety multiplier. With 490 mJ and 4 kg, sqrt(2 × 0.49 J ÷ 4 kg) ≈ 495 mm/sec, and the 0.8 margin brings the indicative limit to about 396 mm/sec.
What is effective mass at the TCP? It is the robot's reflected mass at the tool point in the direction of motion, combining payload and the contributing link inertia, not just the gripper weight. A higher effective mass means a lower safe speed because the same impact carries more energy.
Is this the same as the certified safe speed? No. This is an indicative starting point only. Certified speed comes from measuring transient and quasi-static contact force and pressure with an instrumented gauge against the body-region limits in ISO/TS 15066, then locking the speed in the safety controller.
Why apply a safety margin multiplier? Because the energy model idealizes the impact and ignores edge geometry, soft tissue variation, and tool stiffness. The 0.8 factor pulls the raw 495 mm/sec PFL speed down to about 396 mm/sec to leave headroom before validation.
What is a typical cobot collaborative speed? Many transient-contact scenarios land in the 100 to 250 mm/sec range, and quasi-static (clamping) contacts force much lower speeds. The exact number always depends on the contacted body region and tool geometry, which is why measurement is mandatory.

Last reviewed 2026-08-11.