Three papers from CPSLAB are accepted to IROS 2016


Following three papers are accepted to the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2016):

  • Inverse Reinforcement Learning with Leveraged Gaussian Processes by Kyungjae Lee, Sungjoon Choi, and Songhwai Oh
    • Abstract: In this paper, we propose a novel inverse reinforcement learning algorithm with leveraged Gaussian processes that can learn from both positive and negative demonstrations. While most existing inverse reinforcement learning (IRL) methods suffer from the lack of information near low reward regions, the proposed method alleviates this issue by incorporating (negative) demonstrations of what not to do. To mathematically formulate negative demonstrations, we introduce a novel generative model which can generate both positive and negative demonstrations using a parameter, called proficiency. Moreover, since we represent a reward function using a leveraged Gaussian process which can model a nonlinear function, the proposed method can effectively estimate the structure of a nonlinear reward function.
    • Video
  • Robust Modeling and Prediction in Dynamic Environments Using Recurrent Flow Networks by Sungjoon Choi, Kyungjae Lee, and Songhwai Oh
    • Abstract: To enable safe motion planning in a dynamic environment, it is vital to anticipate and predict object movements. In practice, however, an accurate object identification among multiple moving objects is extremely challenging, making it infeasible to accurately track and predict individual objects. Furthermore, even for a single object, its appearance can vary significantly due to external effects, such as occlusions, varying perspectives, or illumination changes. In this paper, we propose a novel recurrent network architecture called a recurrent flow network that can infer the velocity of each cell and the probability of future occupancy from a sequence of occupancy grids which we refer to as an occupancy flow. The parameters of the recurrent flow network are optimized using Bayesian optimization. The proposed method outperforms three baseline optical flow methods, Lucas-Kanade, Lucas-Kanade with Tikhonov regularization, and Horn-Schunck methods, and a Bayesian occupancy grid filter in terms of both prediction accuracy and robustness to noise. Furthermore, we have shown that the occupancy flow method can effectively be used for navigation in a dynamic environment without tracking moving objects.
    • Video
  • Gaussian Random Paths for Real-Time Motion Planning by Sungjoon Choi, Kyungjae Lee, and Songhwai Oh
    • Abstract:In this paper, we propose Gaussian random paths by defining a probability distribution over continuous paths interpolating a finite set of anchoring points using Gaussian process regression. By utilizing the generative property of Gaussian random paths, a Gaussian random path planner is developed to safely steer a robot to a goal position. The Gaussian random path planner can be used in a number of applications, including local path planning for a mobile robot and trajectory optimization for a whole body motion planning. We have conducted an extensive set of simulations and experiments, showing that the proposed planner outperforms look-ahead planners which use a predefined subset of egocentric trajectories in terms of collision rates and trajectory lengths. Furthermore, we apply the proposed method to existing trajectory optimization methods as an initialization step and demonstrate that it can help produce more cost-efficient trajectories.
    • Video