Martin Proetzsch

Development of complex robotic systems using the behavior-based control architecture iB2C

This paper presents a development methodology for complex robotic systems using the behavior-based control architecture iB2C (integrated Behavior-Based Control). It is shown how architectural principles support several behavior-based mechanisms, e.g. coordination mechanisms, behavior interaction, and hierarchical abstraction. Furthermore, design guidelines and structural patterns are presented which support the design and implementation process. The provided analysis tools and visualization techniques help to manage the complexity of large behavior-based networks. Finally, application examples are presented and a step by step description of constructing a behavior-based control structure for the outdoor robot Ravon is given.

{RAVON} -- The Robust Autonomous Vehicle for Off-road Navigation

Abstract: This chapter describes the work of the Robotics Research Lab at the University of Kaiserslautern in the field of autonomous off-road robotics. It introduces concepts developed for hazard detection, terrain classification, and collision-free autonomous navigation. As an example of a system implementing the described techniques, the mobile off-road robot RAVON is presented. Experiments have been carried out to prove the effectiveness of the approaches.

Simulation and control of an autonomous bucket excavator for landscaping tasks

Introducing autonomous machines to construction areas can improve many of the occurring processes. Therefore, this paper deals with problems in the field of creating an autonomous bucket excavator. A novel behavior-based approach for motion control is presented which allows natural boom trajectories, achieves good environment disturbance compensation behavior, guarantees safety of the movements concerning human beings and structures, and keeps a high extensibility of the system for future improvements. Furthermore, a simulation of soil deals as the basis for safe tests of the excavators behavior in a simulated dynamic environment.

3D obstacle detection and avoidance in vegetated off-road terrain

This paper presents a laser-based obstacle detection facility for off-road robotics in vegetated terrain. In the context of this work the mobile off-road platform RAVON was equipped with a 3D laser scanner and accompanying evaluation routines working on individual vertical scans. Identified terrain characteristics are used to build up a local representation of the environment. Introducing the abstraction concept of virtual sensors the transparent integration of additional terrain information on the basis of standardized behavior modules can be achieved.

The Behaviour-Based Control Architecture iB2C for Complex Robotic Systems

This paper presents the behaviour-based control architecture iB2C (integrated Behaviour-Based Control) used for the development of complex robotic systems. The specification of behavioural components is described as well as the integration of behaviour coordination and hierarchical abstraction. It is considered how the design process can be supported by guidelines and by tools for development as well as analysis. Finally some application platforms are presented and a step by step description of building up a behaviour-based control structure for an outdoor robot is given.

Fault-Tolerant Behavior-Based Motion Control for Offroad Navigation

Many tasks examined for robotic application like rescue missions or humanitarian demining require a robotic vehicle to navigate in unstructured natural terrain. This paper introduces a motion control for a four-wheeled offroad vehicle trying to tackle the problems arising. These include rough ground, steep slopes, wheel slippage, skidding and others that are difficult to grasp with a physical model and often impossible to acquire with sensory equipment. Therefore, a more reactive approach is chosen using a behavior-based architecture. This way a certain generalization in unknown environment is expected. The resulting behavior network is described and experiments performed in a simulation environment as well as in real world are presented. Additionally the performance of the utilized vehicle in case of mechanical or electronic defects is examined in simulation.

Fault-Tolerant 3D Localization for Outdoor Vehicles

This paper presents a robust Kalman-based localization for outdoor vehicles. Outdoor vehicles require a fault-tolerant system that can manage temporary unavailable sensor measurements. The sensor system of the vehicle consists of odometry, inertial measurement unit (IMU) and differential global positioning system (DGPS) receiver. The system allows full 3D localization including position, attitude and velocities. Final experiments showed the localization and navigation capabilities of the outdoor robot RAVON

Extension Approach for the Behaviour-Based Control System of the Outdoor Robot RAVON

This paper describes the extension of a behaviour-based control System for autonomous outdoor navigation. To perform robust obstacle avoidance the existing Stereo vision System is complemented with a 2D laser Scanner. Instead of combining raw sensor data, the additional Information is integrated exploiting behaviour fusion. The Scanner data processing is wrapped into new behaviours, which are added to the existing network. That way no modifications to existing behaviours and interconnections are necessary. Furthermore sensors can be evaluated individually augmenting traceability and testability. The Performance of the resulting System is shown in a real world scenario.

Action/perception-oriented robot software design: An application in off-road terrain

In this paper a combined action/perception-oriented approach for behavior-based robot software design is proposed. Action-oriented in that context denotes that the requirements for sensor information are directly derived from the navigational tasks on the control level. Perception-oriented design on the other hand determines further supporting behaviors from the data available. Taking into account the diversity of sensors and perception algorithms on the one hand and the need for a thorough control methodology on the other, the authors introduce a generic concept for sensor data abstraction through virtual sensors. Virtual sensors are standardized data representations which offer a clear interface for behavior-based robot control systems. The design method presented accounts for both, flexibility on the sensor processing layer and consistent structures on the control layer supporting reusability, extensibility, and traceability. Results documenting the applicability to complex robotic systems are shown in a case study about the off-road platform RAVON.

A Behaviour-Based Integration of Fully Autonomous, Semi-Autonomous, and Tele-Operated Control Modes for an Off-Road Robot

Abstract This paper describes a concept for a behaviour-based integration of tele-operator commands into the control system of a mobile robot. The control system presented features different control modes which allow for pure teleoperation, assisted teleoperation, and fully autonomous navigation. It is explained how the tele-operator can influence the robots motion at any time and how he can simply and continuously change the degree of his influence.