work Point Cloud Models Improve Visual Robustness in Robotic Learners Skand Peri, Iain Lee, Chanho Kim, Li Fuxin, Tucker Hermans, Stefan Lee, ICRA 2024 Simple Masked Training Strategies Yield Control Policies That Are Robust to Sensor Failure Skand Peri, Bikram Pandit, Chanho Kim, Li Fuxin, Stefan Lee, CoRL 2024 fun