GRAPE: Generalizing Robot Policy via Preference Alignment

Despite the recent advancements of vision-language-action (VLA) models on a variety of robotics tasks, they suffer from critical issues such as poor generalizability to unseen tasks, due to their reliance on behavior cloning exclusively from successful rollouts. Furthermore, they are typically fine-tuned to replicate demonstrations collected by experts under different settings, thus introducing distribution bias and limiting their adaptability to diverse manipulation objectives, such as efficiency, safety, and task completion. To bridge this gap, we introduce GRAPE: Generalizing Robot Policy via Preference Alignment. Specifically, GRAPE aligns VLAs on a trajectory level and implicitly models reward from both successful and failure trials to boost generalizability to diverse tasks. Moreover, GRAPE breaks down complex manipulation tasks to independent stages and automatically guides preference modeling through customized spatiotemporal constraints with keypoints proposed by a large vision-language model. Notably, these constraints are flexible and can be customized to align the model with varying objectives, such as safety, efficiency, or task success. We evaluate GRAPE across a diverse array of tasks in both real-world and simulated environments. Experimental results demonstrate that GRAPE enhances the performance of state-of-the-art VLA models, increasing success rates on in-domain and unseen manipulation tasks by 51.79% and 60.36%, respectively. Additionally, GRAPE can be aligned with various objectives, such as safety and efficiency, reducing collision rates by 44.31% and rollout step-length by 11.15%, respectively. All code, models, and data are available at https://grape-vla.github.io/

Host: Hey everyone, and welcome back to another episode of 'Tech Deep Dive'! Today, we're diving into the world of arXiv, that massive repository of pre-print papers. It's a bit of a behemoth, isn't it, Sarah?

Guest: It really is, Leo! I mean, the sheer volume of research papers available there is staggering. It's kind of overwhelming, to be honest. I often find myself lost in the sheer number of options, trying to filter down to something relevant to my current research. I think that's a common experience.

Host: Absolutely! And that's exactly what we'll be exploring today. We'll talk about how to navigate arXiv effectively, how to find the papers that are actually relevant to your work, and also some of the behind-the-scenes stuff – you know, who runs it, how it's funded, and some of the challenges it faces. It’s supported by the Simons Foundation, which is pretty significant, right? That shows the importance of the platform.

Guest: Exactly. The Simons Foundation's involvement is a big deal, highlighting the importance of open-access research and the value of making this research readily available to everyone. The fact that they support it financially speaks volumes about the kind of impact arXiv has. I find it amazing how much research is readily available. It truly is a testament to the collaborative nature of scientific research. And of course, the member institutions also contribute, which creates this really strong network effect.

Host: It's a collaborative effort for sure, and that's one of the things that makes it so powerful. It’s not just about the papers themselves; it's also about the community aspect. You can see the ongoing discussion and evolution of ideas in real-time, sometimes even before formal publication. And it’s amazing how that happens. There's a constant evolution, a dynamic process playing out before our eyes.

Guest: Definitely. And the fact that it's pre-print means you see things before they've gone through the often lengthy peer-review process of traditional journals. That gives you a chance to see the cutting edge of research, potentially spotting trends or insights earlier than you otherwise would. However, that also means you need to be a bit more critical in your assessment, because these aren't yet fully vetted publications. So you need to consider the source and approach it with a discerning eye.

Host: That's a crucial point, Sarah. The lack of formal peer review before publication is both a strength and a weakness. It allows for rapid dissemination of research but also necessitates a more critical reading process for the end user. We should also mention the issue of HTML conversion failures they sometimes experience. That's a significant challenge they face, making some papers difficult to access, which is a bit frustrating sometimes.

Guest: True. I've encountered that myself. It's a bit frustrating when you find a paper that seems really relevant, only to find out that the HTML isn't available. It highlights the enormous technical challenges involved in managing a repository of this size and scale. They've provided instructions for authors on how to help with HTML conversions, which is a step in the right direction.

Host: Exactly. It's a massive undertaking, and they're constantly working to improve accessibility and functionality. But the issues they are facing, like the HTML conversions and the sheer scale of the project, shows us the massive undertaking of arXiv. This emphasizes that despite challenges, they remain a vital resource for the scientific community. And thinking forward, what do you see as the future of arXiv and similar platforms?

Guest: That's a great question. I think we'll see continued growth and, hopefully, further improvements in accessibility and searchability. Perhaps even more integration with other research tools and databases. The potential for AI-powered tools to help researchers navigate and analyze the vast amount of information on arXiv is enormous, making the process more efficient and easier.

Host: Definitely. The possibilities with AI are exciting. Imagine AI helping to identify relevant papers based on your research interests, or even summarizing key findings across multiple papers. That could revolutionize how researchers work. I think we'll see a lot more of that in the coming years. But for now, that's a great starting point for our conversation. We've barely scratched the surface. Let's delve a bit deeper into...