Erwin Prassler

A robotics wheelchair for crowded public environment

Describes the robotic wheelchair MAid (Mobility Aid for Elderly and Disabled People). MAids task is to support and transport people with limited motion skills. It is based on a commercial wheelchair that has been equipped with an intelligent control and navigation system. Conversations with disabled and elderly people and with their physicians indicate that the automatic functions desired in a robotic wheelchair do not include following walls or passing doorways, but do include navigation in narrow, cluttered environments and through wide, crowded areas. MAid performs these functions.

Fast and robust tracking of multiple moving objects with a laser range finder

In this paper we focus on the task of tracking multiple moving objects in rapidly changing, dynamic environments. Objects are extracted from laser range finder images and correspondences between successive images are established by network optimization techniques. The approach is implemented on a robotic wheelchair, used in two applications and evaluated experimentally.

A Short History of Cleaning Robots

The definition of the desired functions and the design of an ultimate versatile personal robot is an ongoing debate. Meanwhile, however, precursors of this yet to evolve species are well on their way to become commercial products. Cleaning robots for public environments as well as for private households seem to be able to provide the breakthrough which the designers of non-industrial robot systems have long awaited.This survey describes a selection of 30 different cleaning robots, with the first developments reaching back more than 15 years. With a few exceptions we have focused on floor cleaning, in particular indoor floor cleaning. We describe a variety of scrubbing and vacuuming robots which were developed for this task. The described systems range from heavy, large, and expensive industrial cleaning vehicles to small-size, light-weight, low-cost household devices. Thesurvey does not include, however, systems for cleaning facades of buildings, or windows, or production tools.Although not all of the 30 cleaning robots abovementioned have yet reached the state of commercial products, their number alone certainly reflects the expectations regarding the economic value associated with the automation of cleaning tasks. In Europe only the estimates for the market for cleaning services range up to the order of US

Navigating a Robotic Wheelchair in a Railway Station during Rush Hour

100 billion per year. It is therefore not surprising that the cleaning industry and the manufacturers of cleaning devices arerather enthusiastic with respect to the automation of cleaning tasks using (semi-)autonomous mobile robot systems.

Editorial Home Automation as a Means of Independent Living

This paper describes the hardware design, control, and navigation system of and some preliminary experiments with the robotic wheelchair Mobility Aid for elderly and disabled people (MAid). MAid’s general task is to transport people with severely impaired motion skills. The authors did not set out to reinvent and redevelop the set of standard skills of so-called intelligent wheelchairs, such as Follow Wall, FollowCorridor, PassDoorway, which are commonly described in the literature. These maneuvers require motion control skills that disabled people, in spite of their disabilities, are eager to learn and quite good at using. Instead, this work focused on generalizing the approach to fine motion control by considering those maneuvers identified as very burdensome due to their duration and required concentration. One of these functions is deliberative locomotion in rapidly changing, large-scale environments, such as shopping malls, entry halls of theaters, and concourses of airports or railway stations, where tens or hundreds of people and objects move around. MAid’s performance was tested in the central station of Ulm during rush hour and in the exhibition halls of the Hannover Messe ’98, the largest industrial fair in the world. Altogether, MAid has survived more than 36 h of testing in public, crowded environments with heavy passenger traffic.

Tracking Multiple Moving Objects for Real-Time Robot Navigation

This special section editorial defines home automation and investigates the various approaches to home automation which can be used to facilitate independent living. The paper concludes by introducing the three technical papers that are part of the special section.

Tracking People in a Railway Station During Rush-Hour

This paper proposes a method for detecting and tracking the motion of a large number of dynamic objects in crowded environments, such as concourses in railway stations or airports, shopping malls, or convention centers. With this motion information, a mobile vehicle is able to navigate autonomously among moving obstacles, operating at higher speeds and using more informed locomotion strategies that perform better than simple reactive manoeuvering strategies. Unlike many of the methods for motion detection and tracking discussed in the literature, our approach is not based on visual imagery but uses 2D range data obtained using a laser rangefinder. The direct availability of range information contributes to the real-time performance of our approach, which is a primary goal of the project, since the purpose of the vehicle is the transport of humans in crowded areas. Motion detection and tracking of dynamic objects is done by constructing a sequence of temporal lattice maps. These capture the time-varying nature of the environment, and are denoted as time-stamp maps. A time-stamp map is a projection of range information obtained over a short interval of time (a scan) onto a two-dimensional grid, where each cell which coincides with a specific range value is assigned a time stamp. Based on this representation, we devised two algorithms for motion detection and motion tracking. The approach is very efficient, with a complete cycle involving both motion detection and tracking taking 6 ms on a Pentium 166 MHz. The system has been demonstrated on an intelligent wheelchair operating in railway stations and convention centers during rush hour.

Cleaning and Household Robots: A Technology Survey

We propose a method for detecting and tracking the motion of a large number of moving objects in crowded environments, such as concourses in railway stations or airports, shopping malls, or convention centers. Unlike many methods for motion detection and tracking, our approach is not based on vision but uses 2D range images from a laser rangefinder. This facilitates the real-time capability of our approach, which was a primary goal. The time-variance of an environment is captured by a sequence of temporal maps, which we denoted as time stamp maps. A time stamp map is a projection of a range image onto a two-dimensional grid, where each cell which coincides with a specific range value is assigned a time stamp. Based on this representation we devised two very simple algorithms for motion detection and motion tracking. Our approach is very efficient, with a complete cycle involving both motion detection and tracking taking 6 ms on a Pentium 166Mhz.

Motion coordination between a human and a mobile robot

This paper describes some of the main technology areas that have been actually used in the development of cleaning robots. The approach taken in this survey is to examine the characteristics of cleaning robots that have made successful laboratory demonstration or have become commercial products. We then identify the technology approach followed by the authors, and group their contributions in a few general areas. The result is a summary of used approaches to thesolution of difficult, albeit very practical, problems in the area of autonomous execution of cleaning tasks.

People tracking using omnidirectional vision and range information

In this paper we describe an approach to coordinating the motion of a human with a mobile robot moving in a populated, continuously changing, natural environment. The approach is based on a method for motion planning amongst moving obstacles known as the velocity obstacle approach. We extend this method by a method for tracking a virtual target which allows us to vary the robots heading and velocity with the locomotion of the accompanied person and the state of the surrounding environment. Our test application is a wheelchair accompanying a person through the concourse of a railway station.