CMU and Siemens develop a monitor for humanoid robots’ safe stopping

2 min read•Sep 29, 2026•

Carnegie Mellon University and Siemens developed PRISM, a method for assessing humanoid robots’ safe stoppability, first reported by Ri. Cutting power can make a humanoid collapse and potentially harm itself or anything it falls on; returning it to a neutral position can also be unsafe near people or obstacles, on slippery or uneven surfaces, or while it holds an object.

Emergency-stop (E-stop) mechanisms are the de facto standard for robot safety, and many robots have a big, easily accessible red button. On an industrial robot mounted in place, pressing an E-stop cuts power and halts all motion; a humanoid needs power to balance and control its joints.

Roboticists have sought to move humanoids into a neutral position before powering them down. In the CMU study, that meant standing with arms hanging down; further steps, such as attaching a support harness, could then allow operators to power down safely.

But the neutral-position fallback can itself be risky around people or other obstacles, on slippery or uneven surfaces, or while the robot holds an object. That makes safe stopping a question of context as well as of halting motion.

Simulations let researchers examine environments and activities that might impede a stop, including rare but critical states, without damaging a robot. They named the resulting method Proactive Refinement of Importance-sampled Stoppability Monitor (PRISM), which defines conditions for safe stoppability and a safety envelope beyond which a humanoid might not stop safely.

PRISM is currently designed for a human controller: it monitors humanoids and alerts operators when a robot may be unable to stop safely. Project lead Yifan Sun, a robotics Ph.D. student, said humanoids could eventually use the method themselves to recognize high-risk situations and avoid or minimize time outside the safety envelope.

Siemens demonstrated PRISM using a commercially available robot a bit more than four feet tall. Researchers found it enabled proactive safety monitoring and could support certification of fail-safe behaviors, a particular interest of Siemens.

The research will be presented at IROS 2026, the International Conference on Intelligent Robots and Systems, Sept. 27-Oct. 1 in Pittsburgh.

Oct 7, 2026

Arizona appeals court vacates manslaughter sentence after AI video

An Arizona appeals court vacated the 10.5-year sentence of Gabriel Horcasitas while upholding his manslaughter conviction, first reported by Nytimes. The case returns to Maricopa County Superior Court for resentencing without the video, after judges found that it presented scripted statements as if the victim himself were speaking in court.

The three-judge panel said the video generated a likeness of Christopher Pelkey’s voice and appearance but did not reflect actual events. It found that allowing and relying on the video made the sentencing fundamentally unfair, and noted that no prior Arizona case had addressed the admissibility of such a depiction at sentencing.

The judges said a victim’s right to speak cannot override a defendant’s right to be sentenced on accurate, reliable information. They said the video collapsed the distinction between the family’s belief about what Pelkey would have said and Pelkey’s own voice and opinions.

The ruling distinguishes family members speaking about Pelkey from a generated likeness that appeared to speak for him.

Pelkey’s sister, Stacey Wales, presented the video during Horcasitas’s sentencing alongside victim-impact statements from family and friends. Wales wrote the script and said her husband and the couple’s longtime business partner helped create the video using Pelkey’s voice from a YouTube video and his face and torso from a funeral-service poster.

Judge Todd F. Lang praised the video as genuine, then imposed the maximum sentence of 10.5 years, more than the nine years prosecutors had sought.

Wales said nobody intended to make the court believe Pelkey was alive or that he had recorded the video before his death. She said she disagreed with the ruling and argued that families use slide shows, collages, hypothetical conversations and poetry to convey grief.

Wales compared the AI video with photography, saying it took 15 years of landmark cases around the 1860s before photography was widely accepted in courts.

The case returns to Maricopa County Superior Court for a new sentencing hearing without the AI-generated video.