1 / 15

CSC-2700 – (3) Introduction to Robotics

CSC-2700 – (3) Introduction to Robotics. Robotics Research Laboratory Louisiana State University. What we learned in last class. Digital Output 8 * 8 LED matrix Techniques for LEDs control on LED matrix Basic I/O operation Define pins on PORTas either input or output ( DDRx )

karan
Download Presentation

CSC-2700 – (3) Introduction to Robotics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. CSC-2700 – (3) Introduction to Robotics Robotics Research Laboratory Louisiana State University

  2. What we learned in last class • Digital Output • 8 * 8 LED matrix • Techniques for LEDs control on LED matrix • Basic I/O operation • Define pins on PORTas either input or output (DDRx) • Output control ( PORTx) • Input read (PINx) • Digital input • Button • Button Flag

  3. How to read only specific PIN on PORT • Ex) bitwise operations Let’s assume that we add 4 buttons on PINA4 ~ 7 and 4 LEDs on PINA0~3 LED0  PIN0, LED1  1, LED2  2, LED3  3 button0  PIN4, button1  PIN5, button2  PIN6, button3  PIN7 DDRA = 0x0F (0b00001111) : PINA0 ~3= output, PIN4~7 = input PORTA = 0xF0 (0b11110000) : pull up from PIN4 to 7 for input PINA = 0xF0 (0b11110000): initial status of PINA All LEDs are off, all buttons are released If LED2 is only need to be on  PORTA = PORTA | 0x04 ( 0b00000100 )  PINA == 0xF4 ( 0b11110100 ) Then, if only button2 is need to be read  PINA & 0x04 ( 0b01000000 ) Button2 released: PINA ( 0b11110100 ) & 0x40 ( 0b01000000 ) 0x40 (0b01000000)

  4. Topics for today • Pulse-width Modulation • What for • How it works • Applications • How to make it • Servo Motor Control • What is servo motor • How it works • Set position of servo head • Simple Hexabot • Walking • Turning • Control hexbot

  5. Pulse-width Modulation • What is it? • Controlling power to inertial electrical devices • Average voltage and current controlled by turning switch • What for? • Modern electronic power switches • The main advantage of PWM is that power loss in the switching devices is very low • Relatively low cost

  6. Pulse-width Modulation • Applications • Fans • Pumps • Robotic Servo • Stepper Motor • Telecommunication

  7. Pulse-width Modulation • How to make it? • Digital Out (PINx) • Special Function I/O Regiser (SFR/SFIOR) • Using a main program • ns_spin( intdelay_time ) ; TOGGLE_PIN(PINxx) • Using interrupts • Timers • PORTB – PINB5 (OCA1), PINB6 (OC1B), PINB7 (OC2) • PORTE – PINE3 (OC3C), PINE4 (OC3B), PINE5 (OC3A)

  8. Power Control (LED brightness) • How to set position of servo head • /home/csc2700/csc2700/10-PWM-dimLight-01 ICR3 = 40000u; // input capture register // pulse cycle (every 40 milli-second) TCNT3 = 0; // interrupt flag register // Set the WGM mode & prescalar TCCR3A = ( 1 << WGM31 ) | ( 0 << WGM30 ) | // timer control register ( 1 << COM3A1 ) | ( 1 << COM3B1 ) | ( 1 << COM3C1 ); TCCR3B = ( 1 << WGM33 ) | ( 1 << WGM32 ) | // timer control register TIMER3_CLOCK_SEL_DIV_8; DDRE |= (( 1 << 3 ) | ( 1 << 4 ) | ( 1 << 5 )); // I/O control register uint16_t count = 0; while (1){ OCR3A = count++; // 0 ~ 65535 (pulse width), PINE3 us_spin(200); }

  9. Servo Motor Control • What is it? • Robotic Arms, RC-Airplane, etc. • Mechanical position change • How does it work? • Position Reader (Potentiometer) • DC-Motor • PWM DC-Motor Controller • Body Frame • Gears • Servo Head

  10. Servo Motor Control • How to set position of a servo head • /home/csc2700/csc2700/10-PWM-Servo-01 intcount = 0; while (1){ switch (count++ % 4){ case(0): OCR3A = 1000; break; // OCR3A is PINE3 , 1000 is 1ms == left (0 degree) case(1): OCR3A = 3000; break; // OCR3A is PINE3 , 3000 is 3ms == middle (90 degree) case(2): OCR3A = 5000; break; // OCR3A is PINE3 , 5000 is 5ms == right (180 degree) case(3): OCR3A = 3000; break; // OCR3A is PINE3 } ms_spin(1000); }

  11. Let’s make a servo move likes windshield wiper

  12. Simple Hexabot • How to make it • ATmega128 Stamp Board • Three servo motors • 3 wires (18 or 19 gauge, 12’ * 3) • Battery (V 5.0)

  13. Simple Hexabot • Let’s make it walk • /home/csc2700/csc2700/10-PWM-HexaBot-01/ intcount = 0; while (1){ LED_OFF(COL0_3x3);LED_OFF(COL1_3x3);LED_OFF(COL2_3x3); switch (count++ % 4){ case(0): SetPWM( PWM_PINE3, RIGHT_FRONT); SetPWM( PWM_PINE4, LEFT_BACK); SetPWM( PWM_PINE5, MID_RIGHT); break; case(1): SetPWM( PWM_PINE3, RIGHT_BACK); SetPWM( PWM_PINE4, LEFT_FRONT); SetPWM( PWM_PINE5, MID_RIGHT); break; case(2): SetPWM( PWM_PINE3, RIGHT_BACK); SetPWM( PWM_PINE4, LEFT_FRONT); SetPWM( PWM_PINE5, MID_LEFT); break; case(3): SetPWM( PWM_PINE3, RIGHT_FRONT); SetPWM( PWM_PINE4, LEFT_BACK); SetPWM( PWM_PINE5, MID_LEFT); break; } ms_spin(100); } #define PWM_PINE3 0 #define PWM_PINE4 1 #define PWM_PINE5 2 #define MID_RIGHT 1300 #define MID_LEFT 1700 #define RIGHT_FRONT 1700 #define RIGHT_BACK 1300 #define LEFT_FRONT 1300 #define LEFT_BACK 1700 void SetPWM( uint8_t pwmNum, uint16_t pulseWidthUSec ){ uint16_t pulseWidthTicks = pulseWidthUSec * 2; // Convert to ticks; switch ( pwmNum ){ case PWM_PINE3: OCR3A = pulseWidthTicks; break; case PWM_PINE4: OCR3B = pulseWidthTicks; break; case PWM_PINE5: OCR3C = pulseWidthTicks; break; } } // SetPWM

  14. Motion planning of simple hexabot • What is a motion in robotics? • Sequence of specific poses with durationㄴ • What motions the simple hexabot can take? • Forward • Backward • Left turn • Right turn • ???

  15. Homework-5 • Create a LED brightness control program, which has a plus button and a minus button • The plus button is for increasing brightness of LEDs • The minus button is for decreasing brightness of LEDs • (bonus) make a simple hexabot control program using 4 buttons • Forward button, backward button, left turn button right turn button

More Related