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XPENG-backed GroundingPI is a 4B open model that teaches robots where things are
Researchers from XPENG, Peking University, the University of Hong Kong and others have released GroundingPI, a 4B-parameter open visual perception model for physical AI. It scored 73.68 across 34 perception benchmarks versus 71.54 for GPT-6 Astra in the team's tests, and as a robot vision backbone it beat rivals with half the demonstration data in simulation.

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Seeing precisely, not just recognising
GroundingPI was built by researchers affiliated with XPENG, Peking University, the University of Hong Kong and other institutions[1]. Its focus is a narrow but basic skill for robots and cars: identifying objects and pinning down exactly where they are. Asked for "the handle of the cup on the right", a system has to find the right cup and then the handle's precise position, and GroundingPI answers with spatial coordinates such as points and bounding boxes[1].
It was trained across 11 perception categories, including object detection, dense object localisation, referring-expression grounding, OCR, document layout, user-interface element recognition and robotic spatial localisation, and notably without robot action labels[1]. The idea is to give downstream action-learning systems a stronger visual foundation[1].
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Benchmarks
Across 34 public perception benchmarks spanning those 11 categories, GroundingPI scored 73.68 on an equally weighted aggregate, the highest of 44 baselines and ahead of GPT-6 Astra's 71.54[1]. It did especially well on scenes with many objects or small targets[1]. XPENG is careful to say this is a perception comparison and not a broader verdict on general intelligence or reasoning[1].
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What it does for robots
The team also plugged GroundingPI in as the visual backbone for robot and driving models[1]:
- Less training data. In RoboCasa-GR1 simulations, systems using GroundingPI hit higher task success with 50% of the demonstration data than comparison models trained on 75%.
- Better in unfamiliar settings. In RoboTwin 2.0, it outperformed mainstream visual backbones across four out-of-distribution settings.
- Driving. On the nuScenes dataset it reached an average open-loop trajectory prediction error of 0.296 metres.
These results come from simulation and offline evaluation, and XPENG says they don't establish readiness for real-world deployment[1].
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Why it matters
Collecting robot demonstrations is slow and expensive, so a vision model that cuts the data needed to learn a task is useful well beyond XPENG. GroundingPI is also a bet that a small specialist perception model, paired with a general model for reasoning and planning, can beat asking one giant model to do everything[1]. XPENG frames it as academic research, not a product announcement for its cars or humanoid robots[1].
FAQ
Frequently asked questions.
01What is GroundingPI?
GroundingPI is an open-source visual perception foundation model of about 4 billion parameters, built by researchers affiliated with XPENG, Peking University, the University of Hong Kong and other institutions. It finds objects and describes where they are with points and bounding boxes, for example locating 'the handle of the cup on the right'.
02How does it compare with bigger models?
In the research team's evaluation across 34 public perception benchmarks in 11 categories, GroundingPI scored 73.68 on an equally weighted aggregate, the highest of 44 baseline models, compared with 71.54 for GPT-6 Astra. XPENG stresses this covers perception tasks only, not general intelligence or reasoning.
03Does it help robots?
In simulation, yes. In RoboCasa-GR1, systems using GroundingPI as their visual backbone beat comparison models with 50% of the demonstration data versus their 75%, and in RoboTwin 2.0 it did better across four out-of-distribution settings. On nuScenes driving data it reached a 0.296-metre average open-loop trajectory error.
04Is it going into XPENG's cars or robots?
Not announced. XPENG describes GroundingPI as an academic research contribution, says the downstream results come from simulation and offline tests, and says it is not a commitment to put it in XPENG's commercial products.
05Where can I get it?
The paper, model weights and code are public, subject to their open-source and third-party licence terms. XPENG lists a project site at groundingpi.github.io, the paper on arXiv, code on GitHub and weights on Hugging Face under GroundingPI/GroundingPI.
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