Ho-Joo Lee

Realtime Generation of Grid Map for Autonomous Navigation Using the Digitalized Geographic Information

In this paper, a method of generating path planning map is developed using digitalized geographic information such as FDB(Feature DataBase). FDB is widely used by the Army and needs to be applied to all weapon systems of newly developed. For the autonomous navigation of a robot, it is necessary to generate a path planning map by which a global path can be optimized. First, data included in FDB is analyzed in order to identify meaningful layers and attributes of which information can be used to generate the path planning map. Then for each of meaningful layers identified, a set of values of attributes in the layer is converted into the traverse cost using a matching table in which any combination of attribute values are matched into the corresponding traverse cost. For a certain region that is gridded, i.e., represented by a grid map, the traverse cost is extracted in a automatic manner for each gird of the region to generate the path planning map. Since multiple layers may be included in a single grid, an algorithm is developed to fusion several traverse costs. The proposed method is tested using a experimental program. Test results show that it can be a viable tool for generating the path planning map in real-time. The method can be used to generate other kinds of path planning maps using the digitalized geographic information as well.

A simulation-based heuristic algorithm for disposition of direction finders

A direction finder is a military weapon that is used to find locations of targets that emit radio frequencies. Multiple direction finders are used in a direction finder system for finding locations of targets in an area of interest. We present a two-stage heuristic algorithm for disposing direction finders in a direction finder system for the objective of maximizing the accuracy of estimation of the location of a target that is assumed to be located in the area of interest. In the suggested heuristic algorithm, a simulation-based method is used for estimating the probability of coverage, the probability that a target is in a given region (of a given size) surrounding the estimated location of the target, and another simulation-based method and a local search method are used to determine locations of direction finders that result in the maximum probability of coverage. Performance of the suggested algorithm is evaluated through computational experiments and results show that the algorithm gives a good disposition plan in a reasonable amount of computation time.

A Method to Determine the Weights for Mission Type based Global Path Planning

Global path planning for autonomous driving of unmanned ground vehicle is essential. When setting global path planning, its accuracy and effectiveness is increased if useful information such as terrain type of driving route has been reflected on global path planning. As a method to reflect the terrain type, there is a method to perform global path planning by applying the weight to each terrain type. At this time, how to assign appropriate weights corresponding to the terrain type is more important than anything. In this paper, we proposed a method to determine the weight for terrain type that may affect the results of global path planning. Moreover, we presented effective operation method and design results(GUI) to check the possibility of the use of the proposed method.

Unit Mission Based Mission Planning and Automatic Mission Management for Robots

ABSTRACT In this paper, it is suggested a method of mission planning and management for robots based on the unit mission. In order to make robots execute given missions continuously as time goes by, a new concept for planning the mission which is composed of one or more unit missions and an automatic mission management scheme are developed. For managing robot’s missions in real time, six management methods are devised as well in order to cope with the mismatches, which occur frequently during the mission execution, as to the initial plan. Without the operator’s involvement, any mismatch can be adjusted automatically by applying one of the mission management methods. The suggested concept of mission planning and mission management methods based on the unit mission are partially realized in the Dog-Horse robot system and it is checked that it can be a viable one for developing effective robot operation systems.Key Words : Robot(로봇), Mission Planning(임무계획), Mission Management(임무관리), Autonomous Navigation(자율주행)

A Terrain Analysis System for Global Path Planning of Unmanned Ground Vehicle

In this paper, we proposed a system that efficiently provides support maps which includes the grid based terrain analysis information. To do this, we use the FDB which is defined as a GIS database that contains features with attributes attached to the features. The FDB is composed of a number of features and feature classes. In order to create support maps, it is necessary to classify feature classes that are associated with each support map and to search them in a grid map. The proposed system use a ontology model to classify semantically feature classes and the quad-tree data structure to find them in a grid map quickly. Therefore, our system is expected to be utilized for global path planning of UGV. In this paper, we show the possibility through an experimental implementation.

Modified

It is necessary that UGV(Unmanned Ground Vehicle) should generate a real-time travesability index map by analyzing raw terrain information to travel autonomously tough terrain which has various slope and roughness values. In this paper, we propose a local path planning method, (Modified ) algorithm, using DVGM (Directional Velocity Grid Map) for unmanned ground vehicle. We also present a path optimization algorithm and a path smoothing algorithm which regenerate a pre-planned local path by algorithm into the reasonable local path considering the mobility of UGV. Field test is conducted with UGV in order to verify the performance of local path planning method using DVGM. The local path planned by is compared with the result of to verify the safety and optimality of proposed algorithm.