Collision Recognition and Direction Changes Using Fuzzy Logic for Small Scale Fish Robots by Acceleration Sensor Data.
ABSTRACT For natural and smooth movement of small scale fish robots, collision detection and direction changes are important. Typical
obstacles are walls, rocks, water plants and other nearby robots for a group of small scale fish robots and submersibles that
have been constructed in our lab. Two of 2-axes acceleration sensors are employed to measure the three components of collision
angles, collision magnitudes, and the angles of robot propulsion. These data are integrated using fuzzy logic to calculate
the amount of propulsion direction changes. Because caudal fin provides the main propulsion for a fish robot, there is a periodic
swinging noise at the head of a robot. This noise provides a random acceleration effect on the measured acceleration data
at the collision instant. We propose an algorithm based on fuzzy logic which shows that the MEMS-type accelerometers are very
effective to provide information for direction changes.
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ABSTRACT: It is important to get information about obstacles to avoid collision for a natural and smooth movement for fish robots. In this paper, we propose an IR sensor-based measurement system which gets information about obstacles for underwater fish robots. Due to complexity and space restriction, IR distance sensors are installed instead of cameras or sonar systems. Much importance is given to the nearby obstacles than those in the distance. A scanning IR sensor and two fixed IR sensors are used in our proposed system to get the pattern information of the obstacles in water. By analyzing the IR sensor data, the estimated shapes of obstacles are recognized. Trajectory control for underwater robots should be designed based on the estimated results of the shapes. Our experimental results show that fish robots, which use our proposed sensor system, make successful movement avoiding collision through channels.
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ABSTRACT: We introduce an autonomous water pollution monitoring system that searches the sources of water pollution and makes measurements of relevant data using a fish robot. A fish robot searches and monitors various areas using GPS receivers and directional information. A fish robot has three microcontrollers which provide full functions, for example, motor operations for the swimming of a fish robot, analog sensor data acquisition including temperature and infrared distance sensors, decoding GPS information, counting the time of sonar in ultrasound sensors and a directional sensor, collecting information of water pollution measurement sensors from Vernier Labpro, and communications. A fish robot swims autonomously in predefined areas and collects the water pollution indexes. Collected information by a fish robot is sent to data collecting nodes by USN motes and Bluetooth, and the data are accessible on the Internet by Ethernet devices.Proceedings of the 6th WSEAS international conference on Computational intelligence, man-machine systems and cybernetics; 12/2007
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ABSTRACT: Design and implementation of an autonomous service robot system based on ubiquitous sensor networks(USN) is proposed. Autonomous acquisition of the position information of a service robot is obtained through the integration of a given global map, USN motes and distance sensors without using cameras. Navigation of the service robot in a building is based on the given building map and the acquired position information. The functions that are relevant to robot movement such as path control, obstacle detection and avoidance are managed by a server notebook PC on the robot platform. According to a given building map, a proper set of locations for USN motes are determined. When a service robot passes by a mote, a set of an LED and a photo-transistor on the service robot and motes detects each other. When a mote detects a specified signal, then it reports to its server immediately. When a service robot detects a mote and then it receives a report from a mote in a short interval of time such as 100 msec, then a server makes decision that the service robot is in front of a mote which reported just before. Since the locations of motes are known, the location of a service robot is determined by the detection sensors and USN motes. Between the USN motes, position data of a service robot is obtained by the distance sensors and encoders that are mounted on the robot platform. Autonomous errand services from any location to given places by user's commands in a large building are possible through experiments by a Pioneer2 and ZigbeX system.