Results/Status Report

Mobile robot and positioning-system are ready!

POSITIONING ELECTRONICS

Robot's positioning electronics consists of a positioning sensor and positioning electronics unit.

POSITIONING SENSOR

Positioning sensor can be divided into two sub systems: first one is LINEAR POSITION TRANSDUCER and the second one is ANGLE SENSOR. With those both sensors we get polar position of the robot inside the cooling tower (angle and distance).

LINEAR POSITION TRANSDUCER

This sensor, know also as a cable extension transducer is based upon the extending wire rope principle. With the transducer mounted at the fixed position, the extension rope is attached to a robot arm. As movement occurs, the extension of the rope rotates an internal capstan and sensing device to produce and electrical output signal proportional to the wire rope extension. An internal torsion spring maintains tension an the wire rope and serves as the retraction mechanism. Sensor is also fully sealed (NEMA 6, IP-68).

Transducer can measure the distances up to 50 meters with the accuracy better than 1%. Output of a sensor is 0 to 10V full scale. Output signal is fed through special cable and sealed connector to robot's positioning electronics.

ANGLE SENSOR

Angle sensor is used for measurement of robot's angle (polar position) toward certain axis of the cooling tower. lt is in special enclosure which is mounted below position transducer unit. With fixing mechanism is complete unit attached to a tripod or a similar stand in the center of a cooling tower.

Robot angle sensor unit contains motor drive mechanics for following the robots position. As robot changes it's position and with this it's angle, the mechanics will turn so the measuring wire is aligned with the robots direction.

Sensing of the alignment of the measuring wire is done by a special developed sensor. This sensor is mounted an the end of a lm long arm. Measuring stainless steel wire is grounded to a sensor chassis. It passes through a sensor which consists of two vertical electrical isolated metal rods. Each of them is connected to motor driving electronics. When ever a wire touches the rod, motor turns the sensor in different direction away, so the wire gets free of a contact. With this is measuring wire always aligned with the robots angle, there fore is no side force the position transducer arm.

The robot's angle is measured by a precision potentiometer. The Signal from the potentiometer is fed to signal conditioning electronics - output of it is 0 to 5V signal full range. The signal is fed through a special cable with the sealed connector toward the electronics unit.

Vehicle characteristics

Internal dimensions of the motor compartment (as seen from the front of the vehicle):

L: 740mm
H: 1150 mm
D: 550 mm

Motors should fit in the compartment, but it is still possible to manufacture the compartment so that larger motors could be fitted.

The motors are brushed, permanent magnet motors (V=12 V, T=12.5 Nm). For control 12 A with radio communication is used.

MORE DETAILS ABOUT VEHICLE CHARACTERISTICS


Tracked vehicle is equipped with the following:

  • two 12V electromotors with gearbox and safety clutch (12.5 Nm each)

  • two rechargeable batteries for up to one shift operation with fast-charging unit

  • radio-control unit (4 channels)

  • B/W CCD camera in water resistant casing, video transmitter and receiver unit

  • vane anemometer, designed for operation in 100% humidity

  • Pt 100 temperature sensor



Mobile robot unit taking data inside cooling tower without disturbing the cooling process.