Designing reward functions is a challenging problem in AI and robotics. Humans usually have a difficult time directly specifying all the desirable behaviors that a robot needs to optimize. One common approach is to learn reward functions from collected expert demonstrations. However, learning reward functions from demonstrations introduces many challenges ranging from methods that require highly structured models, e.g. reward functions that are linear in some predefined set of features to less structured reward functions that on the other hand require tremendous amount of data. In addition, humans tend to have a difficult time providing demonstrations on robots with high degrees of freedom, or even quantifying reward values for given demonstrations. To address these challenges, we present a preference-based learning approach, where as an alternative, the human feedback is only of the form of comparisons between trajectories. Furthermore, we do not assume highly constrained structures on the reward function. Instead, we model the reward function using a Gaussian Process (GP) and propose a mathematical formulation to actively find a GP using only human preferences. Our approach enables us to tackle both inflexibility and data-inefficiency problems within a preference-based learning framework. Our results in simulations and a user study suggest that our approach can efficiently learn expressive reward functions for robotics tasks.

本文介绍了一种基于用户反馈的偏好学习方法，利用高斯过程(GP)对奖励函数进行建模，在不增加结构限制并避免数据不足和刚性的问题的情况下，仅通过比较轨迹即可有效学习机器人任务的表达性奖励函数。

基于主动偏好的高斯过程回归用于奖励学习