A new robotic sensing system which is able to fast measure the
bearing angle with a single ultrasonic transducer by analyzing
the frequency spectrum of the echo using the pulse-echo method.
This robot, Werrimbi (an Australian aboriginal term that means 'bat')
was developed by
Intelligent Robotics Research Centre, Monash University, Australia.
Werrimbi is 560mm in diameter, and 650mm in height, and it has
five Polaroid 7000 series electrostatic transducer with their front
grill removed. Just one central transducer is used in my experiment.
Thank you LK for giving a great opportunity of using Werrimbi.
This research focuse on constructing a new ultrasonic sensing system
which is useful for a mobile robot navigation in indoor envirnment.
In this new sonar-ring sensor system, it is possible to measure the
accurate bearing angles to reflecting points in high speed.
A sonar-ring is one of the most popular sensor for indoor mobile robots, because it is simple and gives omni-directional distance information directly. However, it is difficult to measure accurate bearing of reflecting points by a conventional sonar-ring sensor. And also it is slow to get the 360 degrees directional information due to sequential driving of transducers for avoiding interference. In this new sonar-ring sensor system, it is possible to measure the accurate bearing angles of reflecting objects in high speed. The system employs simultaneous transmission/receive of all directions for the fast measurement,and the accurate bearing angle measurement using differences of time-of-flight.
Acknowledgements : Thanks Mr.Koyanagi for assistance of making a special horn.
A new method of sensor fusion of an omni-directional ultrasonic sensor
and an omni-directional vision sensor.
A new omni-directional sonar, which we developed, can measure
accurate distance and bearing angle of reflecting points,
and an omni-directional vision can give bearing angle to edges of segment.
We propose a sensor fusion method using both the reflecting points measured
by the sonar and the edges of segment measured by the vision,
based on the bearing angles.
Those data are different in character, so they compensate each other
in the proposed method,and it becomes possible to get better information
which are useful for the environment recognition.
Acknowledgements : Thanks Mr.Koyanagi for assistance of setting up.
The fast and accurate sonar-ring was updated with a serial interface as it easily mount on a mobile robot. The system equips sonar-ring transducers, electrical circuits, micro-processors, and a CPU. In the simplest case, you can get position of the points of reflection to your mobile robot via the serial interface.