RoboSSM: Scalable In-context Imitation Learning via State-Space Models
The work, RoboSSM, introduces a novel approach to in-context imitation learning (ICIL) by leveraging state-space models (SSMs), specifically the Longhorn architecture. This contribution addresses a critical limitation in current ICIL methods, which predominantly rely on Transformers. While ICIL offers efficient few-shot adaptation for robotic tasks without requiring online parameter updates, its scalability is hampered by Transformer's quadratic computational complexity with respect to input sequence length. RoboSSM directly tackles this by replacing Transformers with Longhorn, an SSM that exhibits linear-time inference and superior extrapolation capabilities for long contexts. This advancement is significant because it enables ICIL agents to effectively process and learn from longer demonstration sequences, a scenario often encountered in complex, real-world robotic tasks.
Developed by researchers from various institutions including Youngju Yoo, Jiaheng Hu, Yifeng Zhu, Bo Liu, Qiang Liu, Roberto Martín-Martín, and Peter Stone, this research was presented on arXiv. The intended audience for RoboSSM comprises software engineers and researchers in robotics and artificial intelligence who are focused on developing more adaptive and efficient learning systems for robots. The primary benefit is the potential for robots to generalize better to unseen tasks, particularly those requiring long-horizon planning, and to do so with significantly reduced computational overhead during inference.
Two key technical ideas underpin RoboSSM's efficacy. Firstly, the inherent scalability of SSMs, like Longhorn, allows for linear scaling of inference time with respect to the prompt length, a stark contrast to the quadratic scaling of Transformers. This is crucial for handling the lengthy state-action sequences typical of real-world robotic demonstrations. Secondly, the strong extrapolation capabilities of these SSMs enable the model to effectively generalize to contexts longer than those seen during training, a common failure point for Transformer-based ICIL. Experimental results on the LIBERO benchmark validate these claims, demonstrating improved generalization on unseen and long-horizon tasks compared to Transformer baselines.
RoboSSM represents a significant step towards more scalable and practical ICIL. By proving SSMs as an efficient backbone for this paradigm, it opens avenues for deploying more sophisticated imitation learning agents capable of tackling complex, long-duration tasks with fewer demonstrations. This could influence the field by shifting research focus towards SSM-based architectures for robotic learning, enabling the development of robots that can adapt more fluidly to a wider range of real-world challenges. The presented work is an abstract.