Machine ethics is the field that studies how ethical behaviour can be accomplished by autonomous systems. While there exist some systematic reviews aiming to consolidate the state of the art in machine ethics prior to 2020, these tend to not include work that uses reinforcement learning agents as entities whose ethical behaviour is to be achieved. The reason for this is that only in the last years we have witnessed an increase in machine ethics studies within reinforcement learning. We present here a systematic review of reinforcement learning for machine ethics and machine ethics within reinforcement learning. Additionally, we highlight trends in terms of ethics specifications, components and frameworks of reinforcement learning, and environments used to result in ethical behaviour. Our systematic review aims to consolidate the work in machine ethics and reinforcement learning thus completing the gap in the state of the art machine ethics landscape

翻译：机器伦理是研究自主系统如何实现伦理行为的领域。尽管存在一些旨在整合2020年前机器伦理领域最新进展的系统性综述，但这些综述往往未包含以强化学习智能体作为待实现伦理行为主体的研究。原因在于，仅在最近几年我们才观察到强化学习领域内机器伦理研究的增长。本文系统性地综述了面向机器伦理的强化学习研究，以及强化学习框架内的机器伦理问题。此外，我们重点分析了伦理规范制定方法、强化学习的组件与框架结构，以及用于实现伦理行为的训练环境等方面的研究趋势。本系统性综述旨在整合机器伦理与强化学习交叉领域的研究成果，从而完善当前机器伦理研究版图中的空白领域。