WhoBuilt

Why Robotics Still Isn't Solved - But Could Be Soon

Aug 8, 2026· 1 h 24 min· 78K views·Watch on YouTube

Speakers

Y Combinator hosts a robotics research and startup discussion with Stanford researchers Marcel, Milan Ganai, and Tyler Lum, plus Rerun CEO Nico and General Intuition founders Bill and Guanming, on what still limits robotics and how to make progress.

Why robotics remains difficult

The host argues that robotics has repeatedly been declared nearly solved, from AlphaGo and MuJoCo to teleoperation datasets and vision-language-action models. They identify four stubborn challenges: inaccurate physical world models, difficult action representations, limited tactile sensing, and embodiment drift as hardware changes. Collecting teleoperation data is also demanding, making it hard to scale.

Memory for longer robot tasks

Marcel presents Multi-Scale Embodied Memory, developed during an internship at Physical Intelligence, to help policies handle tasks longer than short demonstrations such as folding clothes or making a sandwich. Dense visual memory supports dexterous actions, while a high-level policy stores a compressed text summary of recent events. In examples, memory helps robots stop cooking at the right time and change strategy after repeated mistakes.

Reasoning tailored to each embodiment

Milan Ganai describes R&B Encore, a self-supervised process for finding useful reasoning traces for different robot forms and tasks. A proposer generates candidate explanations, and a validator scores them for brevity, generalization, and whether they help predict actions. The reported results favor movement and gripper-position reasoning for manipulation, and structural affordances for legged navigation; reasoning can also be dropped at inference to avoid added latency.

Dexterity learned in simulation

Tyler Lum presents Sim-to-Real, which uses massively parallel reinforcement learning in simulation to train a single policy for a dexterous hand and arm. The policy tracks object poses from a human video, allowing it to handle unfamiliar tools and tasks without retraining; tests covered 12 unseen tool and behavior combinations. Pose tracking caused about 60% of failures, while random disturbances during training helped the robot recover from dropped objects.

Building robotics businesses and faster world models

Nico argues that robotics startups can begin with a paying customer problem, off-the-shelf hardware, and teleoperation, then use deployment experience to guide data collection and model improvement. He emphasizes customer-site replicas, repeatable evaluation, failure tracking, and data tools suited to multimodal, multi-rate physical data. Bill and Guanming of General Intuition then describe optimizing world action models by reducing diffusion steps and avoiding full future-frame decoding, reporting inference at 500 milliseconds per 16-action chunk on Jetson.

Takeaways

  • Choose a customer problem that can work with teleoperation, then learn its real requirements through deployment.
  • Train and evaluate on collected data early so failures can improve both the model and data collection.
  • For long tasks, give policies a way to track progress and recover from earlier mistakes.
  • Select reasoning signals for the embodiment and task; more annotations are not automatically more useful.
  • Simulation can scale dexterity training, but pose tracking and real-world contact remain important bottlenecks.

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What was claimed 17

  • built
    data catalog and large-scale data backend
    “We also have an infrastructure product called Rerun Hub”
    YouTube
    Verified2 sources· Talk, Job posting· archived
  • built
    open-source SDK for physical data
    “This open-source SDK is pretty popular”
    YouTube
    Verified2 sources· Talk, Job posting· archived
  • role at
    Milan Ganai is researcher at Waymo
    “is currently working at Waymo”
    YouTube
    Unverified1 source· Talk
  • built
    Multi-Scale Embodied Memory system
    “We call this system MEM, or Multi-Scale Embodied Memory.”
    YouTube
    Unverified1 source· Talk
  • previously at
    intern
    “some of the work I did during my internship at Physical Intelligence”
    YouTube
    Unverified1 source· Talk
  • feature
    mem: Combines dense short-context visual memory for a low-level policy with compressed long-context language memory for a high-level policy.
    “Short-context memory consists of dense frames ... Long-context memory is a compressed language representation”
    YouTube
    Unverified1 source· Talk
  • feature
    R&B Encore: Proposes and scores reasoning traces for embodiment alignment, concision, non-triviality, and action predictiveness.
    “a reasoning proposer ... a reasoning validator”
    YouTube
    Unverified1 source· Talk
  • metric
    Sim2Real: Policy runs at 60 hertz controlling a 22-degree-of-freedom hand and 7-degree-of-freedom arm.
    “It runs at 60 hertz and simultaneously controls both the 22-degree-of-freedom hand and the 7-degree-of-freedom arm.”
    YouTube
    Unverified1 source· Talk
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