We consider the problem of learning to follow a desired trajectory when given a small number of demonstrations from a sub-optimal expert. We present an algorithm that (i) extracts the—initially unknown—desired trajectory from the sub-optimal expert’s demonstrations and (ii) learns a local model suitable for control along the learned trajectory. We apply our algorithm to […]
We consider the task of learning to accurately follow a trajectory in a vehicle such as a car or helicopter. A number of dynamic programming algorithms such as Differential Dynamic Programming (DDP) and Policy Search by Dynamic Programming (PSDP), can efficiently compute non-stationary policies for these tasks — such policies in general are well-suited to […]
Motion and path-planning algorithms often use complex cost functions for both global navigation and local smoothing of trajectories. Obtaining good results typically requires carefully hand-engineering the trade-offs between different terms in the cost function. In practice, it is often much easier to demonstrate a few good trajectories. In this paper, we describe an efficient algorithm […]
In case of engine failure, skilled pilots can save a helicopter from crashing by executing an emergency procedure known as autorotation. In autorotation, rather than relying on the engine to drive the main rotor, the pilot has to control the helicopter such that potential energy from altitude is transferred to rotor speed. In fact, maintaining […]
We propose a system for improving grasping using fingertip optical proximity sensors that allows us to perform online grasp adjustments to an initial grasp point without requiring premature object contact or regrasping strategies. We present novel optical proximity sensors that fit inside the fingertips of a Barrett Hand, and demonstrate their use alongside a probabilistic […]
We propose a learning algorithm for estimating the 3-D orientation of objects. Orientation learning is a difficult problem because the space of orientations is non-Euclidean, and in some cases (such as quaternions) the representation is ambiguous, in that multiple representations exist for the same physical orientation. Learning is further complicated by the fact that most […]
We consider the problem of estimating the in- cident angle of a sound, using only a single microphone. The ability to perform monaural (single-ear) localization is important to many animals; indeed, monaural cues are also the primary method by which humans decide if a sound comes from the front or back, as well as estimate […]
We consider the task of planning smooth trajecto- ries for robot motion. In this paper we make two contributions. First we present a method for cubic spline optimization; this technique lets us simultaneously plan optimal task-space tra- jectories and fit cubic splines to the trajectories, while obeying many of the same constraints imposed by a […]
Legged robots offer the potential to navigate highly challenging terrain, and there has recently been much progress in this area. However, a great deal of this recent work has operated under the assumption that either the robot has complete knowledge of its environment or that its environment is suitably regular so as to be navigated […]
High-resolution 3D scanning can improve the performance of object detection and door opening, two tasks critical to the operation of mobile manipulators in cluttered homes and workplaces. We discuss how high-resolution depth information can be combined with visual imagery to improve the performance of object detection beyond what is (currently) achievable with 2D images alone, […]
This paper gives an overview of ROS, an open- source robot operating system. ROS is not an operating system in the traditional sense of process management and scheduling; rather, it provides a structured communications layer above the host operating systems of a heterogenous compute cluster. In this paper, we discuss how ROS relates to existing […]
In apprenticeship learning, we assume that an expert is available who is capable of performing the desired maneuvers. We then leverage these demonstrations to learn all of the necessary components for our control system. In particular, the demonstrations allow us to learn a model of the helicopter dynamics, as well as appropriate choices of target […]
