13-05-2010, 10:22 AM
A robot that will have the capabilities of locating a flame in a mock household, extinguish the flame, and then return to the starting position within the shortest amount of time possible.
The Power System
A Lithium-Ion (Li-Ion) battery will be used as the separate supply specifically designed for the motors.Each of the two motors will be controlled by an H-Bridge. a 14.8V Li-Ion battery pack with a 4400mAh rating was determined to be the best option. a separate 14.8V Li-Ion battery will be used to supply the sensors.
Motor Specifications
To obtain the desired torque and speed, a geared DC motor is the best choice. a gear reduction ratio of 1:18 resulted in a rated torque of 680 g-cm and a rated speed of 310 rpm. An encoder is needed to determine the position and distance that the motor has moved.It is attached at the back of the motor. It is based on the method of quadrature encoding, which basically produces two sinusoidal signals using magnetic Hall sensors.
Motor Control
an H-Bridge would be the best option for the robot. The H-Bridge of the motors will be controlled by the dsPIC33F microcontroller, which will be supplying the PWM signals to the bases of the appropriate transistors.Several H-Bridge motor controller IC's are also supplied by some manufacturers like the L293D. Choice should be based on the current rating of the motors.
Sensors
-Audio Detector:
The circuit, To detect a 3-4 kHz tone that can start the robot , will consist of an NTE832 IC Tone Decoder chip with appropriate external components to create a pass band of 3-4 kHz for the chip. To ensure the tone is detected, an amplifier circuit will be built to feed the signal in from a microphone.
-Ultrasonic Sensors:
To detect hallways and room openings a total of four Devantech SRF05 Ultrasonic Rangers were used.up to 4 meter distances can be read by this.
-Infrared Rangers:
IR rangers will be used To complement the ultrasonic rangers in determining how far away the robot is from the walls in the arena. the Sharp GP2D120 which is used here has a minimum detection distance of 3cm and a maximum of approximately 40cm. This sensor takes a continuous distance reading and outputs an analog voltage which corresponds to this distance.
Flame Detection Sensors:
-Ultraviolet:
the Hamamatsu UVTRON R2868 Flame Sensor is used to detect whether or not a flame is in the periphery of the sensor. The output of this circuit will be connected directly to one of the Holocon microcontrollerâ„¢s input pins.
-Digital Compass:
digital compass is used to To help ensure the robot does not veer too far away from a straight line path.
Fire Extinguisher
The easiest and cleanest method to utilize would be to extinguish the flame with carbon dioxide, or CO2.a linear actuator will be used to pull the trigger of this CO2 bike pump.
For more details, refer this pdf:
http://ece.uakron.edu/SDmaterial/fall200...0Final.pdf
http://ece.uakron.edu/SDmaterial/fall200...Report.pdf
The Power System
A Lithium-Ion (Li-Ion) battery will be used as the separate supply specifically designed for the motors.Each of the two motors will be controlled by an H-Bridge. a 14.8V Li-Ion battery pack with a 4400mAh rating was determined to be the best option. a separate 14.8V Li-Ion battery will be used to supply the sensors.
Motor Specifications
To obtain the desired torque and speed, a geared DC motor is the best choice. a gear reduction ratio of 1:18 resulted in a rated torque of 680 g-cm and a rated speed of 310 rpm. An encoder is needed to determine the position and distance that the motor has moved.It is attached at the back of the motor. It is based on the method of quadrature encoding, which basically produces two sinusoidal signals using magnetic Hall sensors.
Motor Control
an H-Bridge would be the best option for the robot. The H-Bridge of the motors will be controlled by the dsPIC33F microcontroller, which will be supplying the PWM signals to the bases of the appropriate transistors.Several H-Bridge motor controller IC's are also supplied by some manufacturers like the L293D. Choice should be based on the current rating of the motors.
Sensors
-Audio Detector:
The circuit, To detect a 3-4 kHz tone that can start the robot , will consist of an NTE832 IC Tone Decoder chip with appropriate external components to create a pass band of 3-4 kHz for the chip. To ensure the tone is detected, an amplifier circuit will be built to feed the signal in from a microphone.
-Ultrasonic Sensors:
To detect hallways and room openings a total of four Devantech SRF05 Ultrasonic Rangers were used.up to 4 meter distances can be read by this.
-Infrared Rangers:
IR rangers will be used To complement the ultrasonic rangers in determining how far away the robot is from the walls in the arena. the Sharp GP2D120 which is used here has a minimum detection distance of 3cm and a maximum of approximately 40cm. This sensor takes a continuous distance reading and outputs an analog voltage which corresponds to this distance.
Flame Detection Sensors:
-Ultraviolet:
the Hamamatsu UVTRON R2868 Flame Sensor is used to detect whether or not a flame is in the periphery of the sensor. The output of this circuit will be connected directly to one of the Holocon microcontrollerâ„¢s input pins.
-Digital Compass:
digital compass is used to To help ensure the robot does not veer too far away from a straight line path.
Fire Extinguisher
The easiest and cleanest method to utilize would be to extinguish the flame with carbon dioxide, or CO2.a linear actuator will be used to pull the trigger of this CO2 bike pump.
For more details, refer this pdf:
http://ece.uakron.edu/SDmaterial/fall200...0Final.pdf
http://ece.uakron.edu/SDmaterial/fall200...Report.pdf
