  Recently, diffusion model shines as a promising backbone for the sequence
modeling paradigm in offline reinforcement learning(RL). However, these works
mostly lack the generalization ability across tasks with reward or dynamics
change. To tackle this challenge, in this paper we propose a task-oriented
conditioned diffusion planner for offline meta-RL(MetaDiffuser), which
considers the generalization problem as conditional trajectory generation task
with contextual representation. The key is to learn a context conditioned
diffusion model which can generate task-oriented trajectories for planning
across diverse tasks. To enhance the dynamics consistency of the generated
trajectories while encouraging trajectories to achieve high returns, we further
design a dual-guided module in the sampling process of the diffusion model. The
proposed framework enjoys the robustness to the quality of collected warm-start
data from the testing task and the flexibility to incorporate with different
task representation method. The experiment results on MuJoCo benchmarks show
that MetaDiffuser outperforms other strong offline meta-RL baselines,
demonstrating the outstanding conditional generation ability of diffusion
architecture.
