Author name cluster

Fengchi Sun

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5 papers

1 author row

IROS Conference 2012 Conference Paper

Natural feature based localization in forested environments

Meng Song
Fengchi Sun
Karl Iagnemma

This paper presents a new feature based scan matching method for solving 6D localization problem in forested environments. The proposed registration process includes two steps. First, the largest group of approximately parallel tree trunk features is utilized to align successive scans along the five dimensions except z direction. Tree correspondences are established by matching point patterns which are abstracted from the position relationships of trees. The optimal 5D transformation is thus determined based on the axes of two key tree pairs which are selected by evaluating their ability of tree alignment. Second, we assign the ground points of two scans into a grid of cells, and minimize z-direction difference of points in shared cells. The experimental results on data collected in real forested environments have demonstrated the effectiveness of this method.

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ICRA Conference 2012 Conference Paper

Natural landmark extraction in cluttered forested environments

Meng Song
Fengchi Sun
Karl Iagnemma

In this paper, a new systematical method for extracting tree trunk landmarks from 3D point clouds of cluttered forested environments is proposed. This purely geometric method is established on scene understanding and automatic analysis of trees. The pipeline of our method includes three steps. First, the raw point clouds are segmented by utilizing the circular shape of trees, and segments are grouped into tree sections based on the principle of spatial proximity. Second, circles and axes are extracted from tree sections which are subject to loss of shape information. Third, by clustering and integrating the tree sections resulted from various space inconsistencies, straight tree trunk landmarks are finally formed for future localization. The experimental results from real forested environments are presented.

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IROS Conference 2010 Conference Paper

A cooperative approach for multi-robot area exploration

Jing Yuan 0004
Yalou Huang
Tong Tao
Fengchi Sun

A cooperation approach with consideration of communication limit is proposed for multi-robot area exploration, in which all the robots select local destinations satisfying the constraints on communication range and reach their destinations at the same time to communicate and fuse their map information. Firstly, the robots compute the frontier between the explored region and the unexplored one. The robots choose the optimal frontier points, which maximize information gain, minimize navigation cost and satisfy communication limit as their local destinations. Then the problem of global exploration in unknown environment is converted into that of multi-stage trajectory planning in local known environment. Collision-free, synchronous and separate trajectories are planned for all the robots to realize the limited communication at their destinations. In such a way, efficient and distributed exploration can be achieved. Simulation results are presented to show the effectiveness of our method.

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ICRA Conference 2009 Conference Paper

Active exploration using scheme of autonomous distribution for landmarks

Jing Yuan 0004
Yalou Huang
Fengchi Sun
Tong Tao

This paper investigates the on-line autonomous distribution for landmarks and the active exploration in environment without or lack of landmarks/features, such as disaster conditions and polar region. In such situation, the robot enters the environment carrying some landmarks and distributes them according to the rules given in this paper. The utility of the landmark distribution is analyzed. Then, based on the extended Kalman filter (EKF), the active exploration is converted into a problem of multi-objective optimization, in which the objective function includes three aspects, i. e. the accuracy of localization and mapping, the predictive area of the unknown environment that will be explored in next step and the information gain provided by the distributed landmarks respectively. The robot chooses the control input that optimizes the objective function such that accurate localization, high-quality mapping and complete exploration will be realized. And then, the supplementation and the redundancy elimination for landmarks are implemented. At last, a set of simulations is presented to show the effectiveness of our approach.

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IROS Conference 2006 Conference Paper

Optimization Design for Connection Relation of Tractor-Trailer Mobile Robot with Variable Structure

Jing Yuan 0004
Yalou Huang
Fengchi Sun
Yewei Kang

Path planned for tractor-trailer mobile robot (TTMR) does not seem to be easily adapted to the case when the number of the trailers increases, thus the repetitive path planning has to be introduced. For this problem, this paper investigates the connection relation of TTMR with variable structure, i. e. the number of the trailers is variable, and deals with the optimization design for it to avoid the repetitive path planning when the number of the trailers increases. After analyzing the motion trajectories of TTMR, we establish the quantitative relationship for the motion characteristics between the transient course and the steady state. Based on which, a new design method to optimize the connection relation for variable-structure TTMR is proposed. In our scheme, the length of each connecting rod between two adjacent bodies is adjusted properly such that the transient deviations of the trailers from the path followed by the tractor will be less than the steady ones. In such a way, the path planned for TTMR can also be appropriate for the case when the number of the trailers varies. The simulations and experiments show the validity of our method

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