robotic mapping trucks drexel university summer mentorship program michael (bo) franklin driscoll 1,...
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Robotic Mapping TrucksDrexel University Summer Mentorship Program
Michael (Bo) Franklin Driscoll1, Vefa Narli2, Kelly Jean Norris3, Evelyn Cruz4, Rick5, Dr. Paul Oh6
1.Illinois Mathematics and Science Academy, IL2. Grad. Student, Drexel University, PA
3. Teacher, Central High School, PA4. Teacher, Roberto Clemente Middle School, PA
5. Grad. Student, Drexel University, PA6. Associate Professor, Drexel University, PA
Project Conception
• To create a Robotic E-Maxx truck that can map its environment, knowing how far it travels, what angle the obstacles are at, and its angle in relation to the rest of the room, with manual override if need be
• My goal was to work with Vefa to provide the code to use its sensors to avoid obstacles in its path
Hardware Configuration
• Replaced parts to slow down and increase the torque of the Truck so that it would not run too fast for its sensors and be able to stop in time.
• Tougher suspension
• More powerful steering servo
• Larger gear frame
Infrared Sensors
D i s t a n c e ( I n c h e s ) C a r d b o a r d B l a c k D u c t T a p e A l S h e e t C l e a r P l a s t i c
0 8 5 8 5 9 0 U n s u i t a b l e , R a n g e s b y 7 5
2 1 2 8 1 9 3 1 9 9
4 2 2 8 2 0 2 1 9 5
6 1 8 5 1 6 2 1 6 2
8 1 5 9 1 5 0 1 3 9
1 0 1 4 0 1 3 5 1 3 4
1 2 1 2 5 1 3 0 1 2 4
1 4 1 1 2 1 1 3 1 1 7
1 6 9 9 9 8 1 1 2
1 8 8 8 7 9 1 0 7
2 0 8 1 6 4 1 0 0
2 2 7 2 5 9 1 0 2
2 4 6 7 6 0 1 0 0
2 6 6 3 6 1 9 7
2 8 6 1 6 7 8 9
3 0 5 9 6 8 9 2
3 2 5 8 7 0 9 1
•The Sharp GP2D02 IR Ranger gathers data in the form of ASCII characters depending on the range of the object that reflects the infrared light back to the sensor up to a range of 80 cm and a minimum distance of 10 cm. I tested the sensor on four different materials so to determine what setting would be required for the Truck to stop at 16 inches.
Sensor Readings
• To the left is the code used in the PIC (Chip used in the project) to register the readings from the Sensor and interpret measurements. The Sensors transmit the number and if it is lower than 100 it will output a low signal to either pin A0 or A1, depending on which sensor registered the obstruction.
// OUTPUTS IR SENSOR DISTANCE TO SERIAL
#include <16F84A.H>
//xt = Standard Crystal
//hs = High Speed
//rc = resistor capacitor oscillator
//nowdt = No watch dog timer
//noprotect = no code protection
//put = power up timer
#define A0 PIN_A0
#define A1 PIN_A1
#define A2 PIN_A2
#define A3 PIN_A3
#define A4 PIN_A4
#define B0 PIN_B0
#define B1 PIN_B1
#define B2 PIN_B2
#define B3 PIN_B3
#define B4 PIN_B4
#define B5 PIN_B5
#define B6 PIN_B6
#define B7 PIN_B7
#fuses HS,NOWDT,NOPROTECT, PUT
#use delay(clock=10000000)
void main()
{
int i, dist1, dist2, Vout1, Vout2;
while(1)
{
output_low(PIN_A0);
delay_ms(68);
closeness = 0;
for (i=0; i<8; i++) // Reading Distance
{
output_high(PIN_B4);
output_high(PIN_B5);
delay_us(180);
output_low(PIN_B4);
output_low(PIN_B5);
Vout1 = input(PIN_B7);
Vout2 = input(PIN_B6);
delay_us(180);
Vout1 = Vout1<<(7-i);
Vout2 = Vout2<<(7-i);
dist1 = dist1 + Vout1;
dist2 = dist2 + Vout2;
}
output_high(PIN_B4);
output_high(PIN_B5);
delay_us(1500);
output_low(PIN_B4);
output_low(PIN_B5);
if(dist1<100)
{
output_low(PIN_A0);
}
else output_high(PIN_A0);
if(dist2<100)
{
output_low(PIN_A1);
}
else output_high(PIN_A1);
}
}
Sensor Interpretation
// IR SENSOR DISTANCE INPUT IS USED TO TO RUN THE TRUCK
// 3 PWM SIGNALS ARE OUTPUT TO THE TRCUK SERVO
#include <16F84A.H>
//xt = Standard Crystal
//hs = High Speed
//rc = resistor capacitor oscillator
//nowdt = No watch dog timer
//noprotect = no code protection
//put = power up timer
#define A0 PIN_A0
#define A1 PIN_A1
#define A2 PIN_A2
#define A3 PIN_A3
#define A4 PIN_A4
#define B0 PIN_B0
#define B1 PIN_B1
#define B2 PIN_B2
#define B3 PIN_B3
#define B4 PIN_B4
#define B5 PIN_B5
#define B6 PIN_B6
#define B7 PIN_B7
#fuses HS,NOWDT,NOPROTECT, PUT
#use delay(clock=10000000)
void main()
{
int i=0, IR1, IR2;
while(1)
{
IR1 = input(A3);
IR2 = input(A2);
if((IR1 == 1) && (IR2 == 1))
{
output_high(PIN_B6);
output_high(PIN_B7);
delay_ms(1.5);
output_low(PIN_B6);
output_low(PIN_B7);
delay_ms(18.5);
elseif((IR1 == 1) && (IR2 == 0))
output_high(PIN_B6);
output_high(PIN_B7);
delay_ms(1.55);
output_low(PIN_B6);
delay_ms(0.45);
output_low(PIN_B7);
delay_ms(18.00);
elseif((IR1 == 0) && (IR2 == 1))
output_high(PIN_B6);
output_high(PIN_B7);
delay_ms(1.00);
output_low(PIN_B7);
delay_ms(0.55);
output_low(PIN_B6);
delay_ms(18.45);
end
}
}
If the PIC transmits a low signal to A0 or A1 the second PIC which in turn tells the truck whether to turn left or right. The sensors are angled so that they cross each other in front, thus if the left sensor sees an object the truck will turn left instead of right, and if both see the object it will stop.
The sensor takes readings every 70 ms and clocking it 8 times. Thus we had to make sure that the increments for the measurements matched those given by the company. By inserting more code we would slow down the sensor and by using a fast chip would speed it up.
Attaching Sensors to the Truck• The sensors were attached to tin
plates with an aluminum base. The circuitry and PICs were inserted into a breadboard and attached to the aluminum plate on top of the truck.
Conclusion
• The Truck has the ability to recognize objects 16 inches in front of it and will turn to avoid the obstruction and continue on its course.
• At present we do not have the mapping system installed nor do we have a way to give the Truck a destination, these will future additions to the project.
• The manual override code is ready but has not been installed to a chip yet, this should be done very shortly.
Acknowledgments
• Amy Campbell for supporting and providing the Mentorship program
• Dr. Paul Oh for providing me the materials for my research
• Vefa Narli for instructing me on how/what to do• Kelly Jean Norris and Evelyn Cruz for assisting me with
my truck• Drexel University for supplying the Mentorship program• Dr. Peggy Connolly for helping me get into Mentorship• David Grunberg for telling me about Mentorship