General description:

 

 

 

 

 

 

 

 

 

 

 

General description:

DC motors' speed and direction of rotation are controlled by measuring platform pitch angle to maintain balance and provide drive in forward and backward directions. Tilting the steering handle left and right is read by a potentimeter and will cause a speed difference to left and right side motors to enable turning. Scooter balances itself before the driver gets on board.

To determine how much platform is tilted from the horizontal plane, both the angle (in degrees) and anglular velocity (degrees per second) are measured. By combining these measurements and filtering, the resulting calculated angle and anglar velocity are used in conjuction with proportional and derivative terms to calculate the motor setpoints.

Hardware:

• DC motors NPC Robotics B81 FREE SPEED: 170-190 RPM, FREE SPEED CURRENT: 6.5 AMPS MAX.GEAR RATIO: 18:1 (WORM/SPUR)
• TORQUE @ 66 AMPS: 485 LB.IN. MIN.
• SPEED @ 40 LB.IN.: 170 RPM
• BRAKE TORQUE: 680 LB.IN. MIN. AT OUTPUT SHAFT IN BOTH DIRECTIONS.
• Analog Devices Precision ±1.7 g, Dual-Axis iMEMS® Accelerometer ADXL203
• ADXRS 613 150 deg/s gyroscope
• DC Drives: Home-brew (see schematics)
• Controller PIC16F877A, 20 MHz
• Wheels 350x70mm ,tire 3.00-8, tread C-248, mfg. art.nr. R350/70-LAGB
• Axles: Home-brew (see assembly dwgs)
• Batteries:

Software: Compiled with HITECH C

main.c

lcd.c

lcd.h

Documents:

Assembly front, side, top

General Wiring Diagram

Connection diagram

Schematics

DC drives

Controller

PCB's

DC Drive PCB

Controller

Photos

Accelerometer & Gyro

Axle

Lab notes

Coordinates

ADXL 203 Output

ADXRS 613 Output

Parts list