Protecting critical infrastructure against intrusion, sabotage or vandalism is a task that requires a comprehensive situation
picture. Modern security systems should provide a total solution including sensors, software, hardware, and a "control
unit" to ensure complete security. Incorporating unmanned mobile sensors can significantly help to close information
gaps and gain an ad hoc picture of areas where no pre-installed supervision infrastructure is available or damaged after
an incident. Fraunhofer IOSB has developed the generic ground control station AMFIS which is capable of managing
sensor data acquisition with all kinds of unattended stationary sensors, mobile ad hoc sensor networks, and mobile sensor
platforms. The system is highly mobile and able to control various mobile platforms such as small UAVs (Unmanned
Aerial Vehicles) and UGVs (Unmanned Ground Vehicles). In order to establish a real-time situation picture, also an
image exploitation process is used. In this process, video frames from different sources (mainly from small UAVs) are
georeferenced by means of a system of image registration methods. Relevant information can be obtained by a motion
detection module. Thus, the image exploitation process can accelerate the situation assessment significantly.
The use of miniature Unmanned Aerial Vehicles (UAVs), e.g. quadrocopters, has gained great popularity over
the last years. Some complex application scenarios for micro UAVs call for the formation of swarms of multiple drones.
In this paper a platform for the creation of such swarms is presented. It consists of commercial quadrocopters enhanced
with on-board processing and communication units enabling autonomy of individual drones. Furthermore, a generic
ground control station has been realized. Different co-operation strategies for teams of UAVs are currently evaluated
with an agent based simulation tool. Finally, complex application scenarios for multiple micro UAVs are presented.
Based on small mobile robots the presented MINIMAN system provides a platform for micro-manipulation tasks in very different kinds of applications. Three exemplary applications demonstrate the capabilities of the system. Both the high precision assembly of an optical system consisting of three millimeter-sized parts and the positioning of single 20-μm-cells under the light microscope as well as the handling of tiny samples inside the scanning electron microscope are done by the same kind of robot. For the different tasks, the robot is equipped with appropriate tools such as micro-pipettes or grippers with force and tactile sensors. For the extension to a multi-robot system, it is necessary to further reduce the size of robots. For the above mentioned robot prototypes a slip-stick driving principle is employed. While this design proves to work very well for the described decimeter-sized robots, it is not suitable for further miniaturized robots because of their reduced inertia. Therefore, the developed centimeter-sized robot is driven by multilayered piezoactuators performing defined steps without a slipping phase. To reduce the number of connecting wires the microrobot has integrated circuits on board. They include high voltage drivers and a serial communication interface for a minimized number of wires.
Proc. SPIE. 4568, Microrobotics and Microassembly III
KEYWORDS: Optical microscopes, Sensors, Databases, Electron microscopes, Control systems, Scanning electron microscopy, Telecommunications, Object recognition, Optical scanning systems, Algorithm development
As part of a European Union ESPRIT funded research project a flexible microrobot system has been developed which can operate under an optical microscope as well as in the chamber of a scanning electron microscope. The system is highly flexible and configurable and uses a wide range of sensors in a closed-loop control strategy. This paper presents an overview of the vision system and its architecture for vision-controlled micro-manipulation. The range of different applications, e.g. assembly of hybrid microsystems, handling of biological cells and manipulation tasks inside an SEM, imposes great demands on the vision system. Fast and reliable object recognition algorithms have been developed and implemented to provide for two modes of operation: automated and semi-automated robot control. The vision system has a modular design, comprising modules for object recognition, tracking and depth estimation. Communication between the vision modules and the control system takes place via a shared memory system embedding an object database. This database holds information about the appearance and the location of all known objects. A depth estimation method based on a modified sheet-of-light triangulation method is also described. Furthermore, the novel approach of electron beam triangulation in the SEM is described.
In the scanning electron microscope (SEM), specially designed microrobots can act as a flexible assembly facility for prototype microsystems, as probing devices for in-situ tests in various applications or just as a helpful teleoperated tool for the SEM operator when examining a few samples. Several flexible microrobots of this kind have been developed and tested. Driven by piezoactuators, these few cubic centimeters small mobile robots perform manipulations with a precision of up to 20 nm and transport the gripped objects at speeds of up to 3 cm/s. New microrobot prototypes being employed in the SEM are described in this paper. The SEM's vacuum chamber has been equipped with various elements to enable the robots to operate. In order ot use the SEM image for automatic real-time control of the robots, the SEM's electron beam is actively controlled by a PC. The latter submits the images to the robots' control computer s ystem. For obtaining three- dimensional information in real time, a triangulation method with the luminescent spot of the SEM's electron beam is being investigated. Finally, the strategies of a micro force sensing and control methods required for handling techniques with two robots are discussed.
The assembly of complex microsystems consisting of several single components (i.e. hybrid microsystems) is a difficult task that is seen to be a real challenge for the robotics research community. It is necessary to conceive flexible, highly precise and fast microassembly devices and methods. In this paper, the development of a microrobot-based microassembly station is presented. Mobile piezoelectric microrobots with dimensions of some cm3 and with at least 5 DOF can perform various manipulations either under a light microscope or within the vacuum chamber of a scanning electron microscope. The control system of the microassembly station is described. The main attention is given to a vision-based sensor system for automatic robot control and a re-configurable parallel computer array enabling the station to work in real-time.