Neural scalarisation for multi-objective inverse reinforcement learning

Multi-objective inverse reinforcement learning (MOIRL) extends inverse reinforcement learning (IRL) to multi-objective problems by estimating weights and multi-objective rewards to help retrain and analyse preference-conditioned behaviour. Unlike previous methods using linear scalarisation, we propose a MOIRL method using neural scalarisation. This method comprises four neural networks: weight mapping, reward, scalarisation and weight back-translation. Additionally, we introduce two stabilization techniques for learning the proposed method. Experiments show that the proposed method can estimate appropriate weights and rewards reflecting true multi-objective intentions. Furthermore, the estimated weights and rewards can be used for retraining to reproduce the expert solutions.