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Research Project TSR


Tele-Sensory guided Robot (TSR)


In recent years there has been an increasing interest in the technology of multi-modal tele-presence - a term that describes the extension of the sensory and manipulative abilities of operators into a remote environment. This research area has yielded many interesting applications, including tele-operation in hazardous environments (astronautics or nuclear facilities), tele-maintenance und tele-service at a great distance, tele-surgery and tele-shopping. In all the examples mentioned above, a barrier of some kind (distance, scale, medium) exists between the local operator and the remote environment, a barrier that is overcome by the tele-presence application.

At GET Lab, the possible fields of applications of computer vision and especially pattern recognition methods for tele-sensory applications are being explored. For this reason, a mobile robot was constructed for use as a research platform. So that it is applicable for tele-sensory uses, the system is equipped with several different physical sensors. For the research interest of our working group, the stereo camera system is of particular importance.

The goal of a tele-sensory application is to replace the sensual perception of an operator by sensor acquisition to the highest possible degree. For human beings, vision is of great importance because the visual system is the most powerful sense. Humans mostly depend on visual perception for orientation and for comprehending their environments. For this reason, TSR is equipped with visual sensors as well, which are represented by two cameras on the platform, mounted on a stereo camera head. The camera head provides two mechanical degrees of freedom to adjust the optical axes. With two servo motors, the stereo head can be justified both horizontally and vertically. The cameras themselves are arranged in parallel optic.

In addition to vision, hearing represents an important source of information for humans. Therefore, sensors for acoustics are integrated in the robot as well. Two microphones are installed directly next to the stereo camera head. They support the optical sensors in the acquisition of data on the environment, and so amplify the effect of tele-presence.

Furthermore, TSR possesses active infrared (IR) sensors, which are used for distance estimation based on active triangulation. They are assisted in this task by ultrasonic (US) sensors, which can cover a larger range than IR sensors. A small processor (basic stamp) is integrated in the vehicle for on-board data processing. The distance estimation assists the operator controlling TSR in avoiding collision. In addition, the distance estimation supports the navigation in an autonomous operating mode.

A sensor ring with IR receivers is used to register IR signals from the environment. The acquisition range covers 360 degrees completely. Thus, predefined points that are marked with the IR transmitter can be detected, and TSR can autonomously navigate towards them. One conceivable application is autonomous navigation to a charging station when the storage battery is low. Another important possible field of application is the autonomous position estimation of the robot. If TSR is able to detect at least two IR transmitters with defined positions in its surrounding, self-localisation is possible. This position estimation can be useful for autonomous navigation.

The integration of additional sensors, among others acceleration and inclination sensors, is already in the works. If the robot is placed on an inclined plane, when the operator receives visual information from the stereo cameras he is not able to register his exact position and orientation without further information such as an artificial horizon. The reason for this problem is rooted in the missing sense of equilibrium. Therefore, the visualisation of an artificial horizon in the stereo images will provide the operator with the required information.

For control tasks, motion detection sensors are integrated in the robot. With the aid of the sensors mentioned above, the robot can be re-activated from an energy-saving stand-by mode. Thus the operation of TSR can be assured over a longer period of time without high power consumption. And it can be guaranteed that essential occurrences will be recognized.

Furthermore, the sensory function is extended with an electronic compass and a GPS-receiver. With this equipment, self-localization during autonomous mode and navigation by an operator is supported.






University of Paderborn fonds


Prof. Dr.-Ing. Bärbel Mertsching