Hubert Roth

Haptic interfaces for the remote control of mobile robots

Abstract Teleoperation of mobile robots benefits from the extension of the sensor capabilities by force feedback. Usually telerobotic applications provide to the remote user images and navigation sensor data. With additional force feedback, not only visual but also haptic interfaces provide inputs to the teleoperator in order to improve the remote control performance. This paper describes the hard- and software implementation for controlling a mobile robot over the Internet by the use of a force feedback joystick.

Mobile robots for search and rescue

Mobile robots are integrated into a search and rescue team as tools for searching victims in dangerous areas that is harmful for human, as to provide the perception data for map building, and as to follow the human entity during the mission. The teleoperated control and the autonomous path following is implemented on the robots for the semiautonomous navigation in the simulated firing scenario. This paper focuses on the robot entities in the PeLoTe project (building presence through localization for hybrid telematic teams). The architecture of the software integration for mobile robots into the PeLoTe system and the experimental results are presented.

Modular Reactive Neurocontrol for Biologically Inspired Walking Machines

A neurocontroller is described which generates the basic locomotion and controls the sensor-driven behavior of a four-legged and a six-legged walking machine. The controller utilizes discrete-time neurodynamics, and is of modular structure. One module is for processing sensor signals, one is a neural oscillator network serving as a central pattern generator, and the third one is a so-called velocity regulating network. These modules are small and their structures and their functionalities are analyzable. In combination, they enable the machines to autonomously explore an unknown environment, to avoid obstacles, and to escape from corners or deadlock situations. The neurocontroller was developed and tested first using a physical simulation environment, and then it was successfully transferred to the physical walking machines. Locomotion is based on a gait where the diagonal legs are paired and move together, e.g. trot gait for the four-legged walking machine and tripod gait for the six-legged walking machine. The controller developed is universal in the sense that it can easily be adapted to different types of even-legged walking machines without changing the internal structure and its parameters.

Detection and Classification of Moving Objects-Stereo or Time-of-Flight Images

This paper describes a system for detection and classification of moving objects based on support vector machines (SVM) and using 3D data. Two kinds of camera systems are used to provide the classification system with 3D range images: time-of-flight (TOF) camera and stereo vision system. While the former uses the modulated infrared lighting source to provide the range information in each pixel of a photonic mixer device (PMD) sensor, the latter employs the disparity map from stereo images to calculate three dimensional data. The proposed detection and classification system is used to classify different 3D moving objects in a dynamic environment under varying lighting conditions. The images of each camera are first preprocessed and then two different approaches are applied to extract their features. The first approach is a computer generated method which uses the principal component analysis (PCA) to get the most relevant projection of the data over the eigenvectors and the second approach is a human generated method which extracts the features based on some heuristic techniques. Two training data sets are derived from each image set based on heuristic and PCA features to train a multi class SVM classifier. The experimental results show that the proposed classifier based on range data from TOF camera is superior to that from the stereo system

Navigation and docking manoeuvres of mobile robots in industrial environments

The actual developed generation of automated guided vehicles (AGVs), used for the flow of materials in industrial production lines, offer increased flexibility by storing the reference path in the vehicles on-board computer. This requires an effective path planning strategy, in particular with respect to navigation, collision avoidance and docking to target stations. Sensors to support these manoeuvres need to be robust, to survive in the rough industrial environment, cheap, to be an alternative to the existing wire-guided vehicles, and accurate, to meet the performance requirements. To cope with all these topics different low-cost sensors have to be used and their information has to be fused by intelligent algorithms. This paper addresses the combination of measurement signals of simple CCD-cameras, odometry sensors and ultrasonic sensors for a low cost approach to free navigation including target docking. The performance of this concept has been proofed by factory trial tests in the frame of the ESPRIT-project RETRARO in the production environment of the company Schoeller-Bregenz, active in the area of wool processing and spinning.

Inspection- and repair robots for waste water pipes a challenge to sensorics and locomotion

Sewerage is a very large and important infrastructure in the water industry. Because around 20% of the municipal pipe network is estimated to be significantly damaged, it is of high priority to inspect, maintain and repair public sewers. During recent years mobile robots have been developed to inspect but also to repair the pipes. To navigate through the hostile environment, they are generally only equipped with video cameras and connected to the outside world via an umbilical cord which transmits the image information. The tethered robots are tele-operated from a remote service station placed at the end of a maintenance shaft. These pipe robots are commonly wheeled systems especially adapted to withstand the adverse conditions of the waste pipe environment. In this paper the actual state of the art in the field of mobile robots for repair and inspection of sewerage is given and the possible improvements of the next generation of robots caused by developments of the sensors, the material, the tele-operation techniques and the locomotion principles are reported. This will allow the robots to increase their capabilities and to enlarge the application areas to pipes with smaller diameters and pipes in industrial plants.

A Hybrid Approach Based on ACO and Ga for Multi Objective Mobile Robot Path Planning

In this study, we developed an Ant Colony Optimization (ACO) - Genetic Algorithm (GA) hybrid approach for solving the Multi objectives Optimization global path planning (MOPP) problem of mobile robot. The ACO optimization algorithm is used to find the sub-optimal collision free path which then used as initial population for GA. In the proposed modified genetic algorithms, specific genetic operator such as deletion operator is proposed, which is based on domain heuristic knowledge, to fit the optimum path planning for mobile robots. The objective of this study is improving GA performance for efficient and fast selection in generating the Multi objective optimal path for mobile robot navigation in static environment. First we used the proposed approach to evaluate its ability to solve single objective problem in length term as well as we compared it with traditional ACO and simple GA then we extended to solve Pareto optimality ideas based on three criteria: length, smoothness and security, and making it Multi objective Hybrid approach. The proposed approach is tested to generate the single and multi objective optimal collision free path. The simulation results show that the mobile robot travels successfully from one location to another and reaches its goal after avoiding all obstacles that are located in its way in all tested environment and indicate that the proposed approach is accurate and can find a set Pareto optimal solution efficiently in a single run.

Application of 3D-PMD video cameras for tasks in the autonomous mobile robotics

Abstract Fast Localisation is a basic function within the mobile robotics. Beside the odometrie, mainly image sensors are used. This paper shows a short overview of the image sensors used for it. Outgoing from the 2D, 3D laser scanner, over 2D mono camera and 2D stereo camera, up to the omni-directional 2D camera are described problems, which appear in recording and modelling of the robot environment with such sensors. In this paper in comparison to the classical sensors a completely new 3D-PMD video camera is introduced as a more efficiently image sensor. This sensor can not only record the robot environment as normal 2D image but delivers furthermore additionally with the depth information into a three-dimensional video image. Concerning of speed and accuracy, new possibilities are opened in object and obstacle recognition, localization and autonomous map generation, within the mobile robotics.

Indoor Navigation of Mobile Robots Based on Natural Landmarks

Abstract To derive cost efficient solutions, navigation of mobile robots should take advantage of known facts of the environment, like maps of buildings. This paper discusses the use of range sensor measurements at characteristic locations to periodically correct the drift in odometry data, in order to derive the vehicle’s position and orientation with sufficient accuracy. The main objective is to provide a low cost navigation system without the need for external reference marks. This paper outlines the approach, the sensor data processing algorithm and results of performance tests in industrial environments.

Information and communication technology embraces control: Status report prepared by the IFAC Coordinating Committee on Computers, Cognition and Communication

Abstract A new approach in control engineering (“Information Processing for Action”) is presented, in which control, computers, communication and cognition play equal roles in addressing real-life problems from very small-scale devices to very large-scale industrial processes and non-technical applications. Thus, the C2 paradigm of “Computers for Control” is shifting towards the C4 paradigm of “Computers, Communication and Cognition for Control” providing an integrated perspective on the role computers play in control systems and control plays in computer systems. This change is mainly due to new developments in computers and knowledge management, and the rapidly emerging field of telecommunications providing a number of possible applications in control. Control engineers will have to master computer and software technologies to be able to build the systems of the future, and software engineers need to use control concepts to master the ever-increasing complexity of computing systems.