INSIDER CASE STUDY: SAFE GUIDED FALLING FOR A HUMANOID ROBOT
How do you make a humanoid robot safe?
A safe stop alone isn’t enough. If a humanoid robot loses power, communication, or its balance, it can enter a state where a fall is unavoidable—and Safe Torque Off doesn’t work on two legs. Traditional safety features were developed for industrial robots with six or seven axes that are firmly bolted to the floor. A humanoid robot has 30 or more axes and stands freely in space. To this day, there is no standard safety architecture that could simply be adopted.
In the latest episode of our video series "Insider Case Study," we show how we solved this very problem for a humanoid robot manufacturer—based on a real-world client project.
THE BACKGROUND
The customer’s robot platform was already fully developed, and the actuators had been specified. Our task: to integrate a multi-axis safe-motion system and connect it to a safe-human-detection system—including kinematic calculations, safety zone calculations, and damping behavior at the system level. And we had to do all this within the extremely tight timeline that is typical in the humanoid industry.
THE SOLUTION: POSITRON ON THE STA1
We have integrated POSITRON Safety AI into the POSITRON STA1, our ARM-based safety controller (certified to SIL3 / PLe). On this platform, we implemented a multi-axis safety layer supporting up to 30 axes. Instead of relying solely on Safe Torque Off, the solution is based on Safe Active Damping at the drive level—thereby enabling Safe Guided Falling at the system level: The unavoidable fall is transformed into a controlled, safe movement. The hardware is based on our standard compute unit, adapted to the customer’s form factor and connectors.
THE RESULT
A humanoid safety controller built to address real-world problems. It's not just about stopping movement—it's about what happens when stopping is no longer an option.
FREQUENTLY ASKED QUESTIONS
Why isn't Safe Torque Off sufficient for humanoids?
Safe Torque Off cuts off the torque—causing a bipedal robot to lose its stability and fall uncontrollably. Humanoid safety systems must therefore also be able to handle situations in which a fall is unavoidable.
What is Safe Guided Falling?
Safe Guided Falling transforms an unavoidable fall into a controlled, safe movement. It is based on Safe Active Damping at the drive level, combined with kinematic and safety zone calculations at the system level.
What is the POSITRON STA1?
The POSITRON STA1 is Synapticon's ARM-based safety controller (embedded computing module with a dual 800-MHz CPU), certified to SIL3 / PLe. It can be customized to meet customer-specific form factors and connector requirements.
More about the platform: POSITRON Safety AI
