Development of Multifunctional Service Robots
The goal of this project is to develop multi-functional indoor service robot systems called PSR (Public Service Robots). They are mobile-manipulator typed service robots developed towards intelligent agents in a real environment. We built three versions of platforms, which are the mobile manipulator PSR-1 and PSR-2, and the guide robot Jinny. The PSR robots successfully accomplished four service tasks including delivery, patrol, guide, and floor cleaning. Fig.1 shows the hardware configurations of three PSR systems. The PSR-2 is an upgraded version of the PSR-1, so they have similar configurations. The Jinny is a specialized version aiming at a commercial guide robot with a human friendly appearance.
Fig.2 shows an example of navigation in a conventional office building. The start point is node0, and goal is node2 as shown in Fig.2.(a). Fig.2.(b) presents a planned path and an actual trajectory during the navigation. The robot's actual trajectory has the discontinuity that mainly results from position updates by the localizer. Fig.2.(c) shows the results of localization. It represents the local map, laser scan data, reference data, sample distributions, and estimated position. The data for path planning and localization is gathered simultaneously in a single experiment. The reference measurements of an estimated robot location are mostly consistent with the scanned measurements of an actual robot position. It means that the accurate position estimation is accomplished. Although the environment is slightly changed and users disturb the robot's way, the proposed localization algorithms work successfully.
Four service tasks were successfully implemented to three PSR platforms. (See Fig.3).
A. Delivery Initially, a user commands a task by giving initial and destination room numbers through the remote computer or the interface device on the PSR. Then, the PSR navigates to the room where the target box is. When it reaches in front of the room, it releases the trailer and enters the room alone. After the PSR picks up the box, the PSR leaves the room and places the box on the trailer. Next, the PSR docks the trailer again and moves to the target room to place the box in the pre-determined position.
B. Cleaning The scenario of a floor cleaning is as follows. The robot is initially loads the grid map of a target workspace, and then, divides it into several sections if it is a large open space. Each section is swept by the full-coverage algorithm based on the wall following behavior.
C. Guide The guide task was implemented into the Jinny platform toward installation in the National Science Museum of Korea. The Jinny autonomously navigated the crowded environment and explained exhibits to visitors. A user can select the scenario by selecting the sequence of exhibits to be explained. The Jinny also provides several interesting services including a simple game with visitors, and dance to the music, and following visitors using laser range data.
D. Patrol The patrol task can be easily achieved since only navigation capability is required. For omni-directional surveillance, a pan tilt camera and four web cameras are set up on the top of the PSR-2. The robot can broadcast camera images to the monitoring station. Delivery Clearning Guidance Patrol Figure 3. Four service tasks - Delivery, Cleaning, Guide, and Patrol.