In this paper, we consider the agreement problem of estimating the locations of landmarks observed by multiple
agents in the absence of a global frame of reference. Maximum likelihood estimators are derived from scenarios
of independent and mutual landmark estimation. A triangle-based hypothesis test is proposed for the detection
of common landmarks across the coordinate systems of the agents and is followed by a formulation of triangle
matching as a linear assignment problem. A landmark agreement model is also proposed with consideration that
the agents may observe both common and uncommon landmarks. Simulation examples are provided illustrating
the proposed landmark estimation and triangle matching approaches.
This paper explores representations for capturing the anticipation of other objects by an autonomous robot in
an urban environment. Predictive Gaussian mixture models are proposed due to their ability to probabilistically
capture continuous and discrete obstacle behavior; the predictive system uses the probabilistic output of a
tracking system (current obstacle location), and map (with lanes and intersections). The probabilistic tracking
and anticipated motion are integrated into an optimized path planner. This paper explores various levels of
model abstraction to understand how complex these predictive models must be in order to create a more robust
path planning algorithm.
Daniel Lee, Mark McClelland, Joseph Schneider, Tsung-Lin Yang, Dan Gallagher, John Wang, Danelle Shah, Nisar Ahmed, Pete Moran, Brandon Jones, Tung-Sing Leung, Aaron Nathan, Hadas Kress-Gazit, Mark Campbell
This paper presents an overview of a human-robotic system under development at Cornell which is capable of
mapping an unknown environment, as well as discovering, tracking, and neutralizing several static and dynamic
objects of interest. In addition, the robots can coordinate their individual tasks with one another without overly
burdening a human operator. The testbed utilizes the Segway RMP platform, with lidar, vision, IMU and GPS
sensors. The software draws from autonomous systems research, specifically in the areas of pose estimation,
target detection and tracking, motion and behavioral planning, and human robot interaction. This paper also
details experimental scenarios of mapping, tracking, and neutralization presented by way of pictures, data, and
movies.
The local path planner implemented on Cornell's 2007 DARPA Urban Challenge entry vehicle Skynet utilizes a novel mixture of discrete and continuous path planning steps to facilitate a safe, smooth, and human-like driving behavior. The planner first solves for a feasible path through the local obstacle map using a grid based search algorithm. The resulting path is then refined using a cost-based nonlinear optimization routine with both hard and soft constraints. The behavior of this optimization is influenced by tunable weighting parameters which govern the relative cost contributions assigned to different path characteristics. This paper studies the sensitivity of the vehicle's performance to these path planner weighting parameters using a data driven simulation based on logged data from the National Qualifying Event. The performance of the path planner in both the National Qualifying Event and in the Urban Challenge is also presented and analyzed.
Satellites based on microelectromechanical system (MEMS) technology and tailored to low-cost space missions are investigated to determine their characteristics and feasibility. This work explores an alternative chassis formed from a stack of microfabricated silicon wafers. The outer layers contain optical sensing, micropropulsion and power generation systems whereas internal layers contain computers, RF components and mechanical sensors. This technique has the advantage of saving space and weight while allowing for easy design changes and precise tailoring to mission specifications. This concept is expanded through a design study of the MEMS control moment gyroscope which is used in satellite attitude control. In addition, a feasibility study is performed with special regard to the alternative chassis outlined above. This work (part of a Phase I NASA Institute for Advanced Concepts study) demonstrates that a wide variety of spacecraft components can be fabricated with silicon processing techniques. This approach may lead to batch- fabricated, high-volume, low cost, redundant teams of MEMS spacecraft.
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