root / forklift / code / forklift.c @ 902fa82f
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/*
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* ARM -> us
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* -height setpoint
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*
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* us -> ARM
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* -tracking ID (same for all forklifts)
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* -serial number (unique to each forklift)
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* -current height
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* -current height setpoint
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* -payload weight
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*
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*/
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#include "twi.h" |
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#include "analog.h" |
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#include "motor.h" |
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#include <avr/io.h> |
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#include <avr/interrupt.h> |
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#define TRACKING_ID 0x41 |
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#define SERIAL_NUMBER 0x12 |
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// indicies for forklift internal data
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#define FORKLIFT_TRACKING_ID 0 |
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#define FORKLIFT_SERIAL_NUMBER 1 |
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#define FORKLIFT_HEIGHT 2 |
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#define FORKLIFT_HEIGHT_SETPOINT 3 // r/w |
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#define FORKLIFT_LINE_POS 4 |
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#define FORKLIFT_LINE_THRESH_HIGH 5 // r/w |
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#define FORKLIFT_LINE_THRESH_LOW 6 // r/w |
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#define FORKLIFT_LINE_VALS_START 7 |
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#define FORKLIFT_LINE_VALS_END 12 // non-inclusive |
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#define FORKLIFT_DATA_LEN 12 |
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uint8_t internal_index = 0;
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uint8_t internal_data[] = { |
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TRACKING_ID, |
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SERIAL_NUMBER, |
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0,
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100, // default height setpoint |
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0,
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0,
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150, // default line threshold |
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0,
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0,
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0,
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0,
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0
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}; |
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int error;
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int i_term;
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void init_int0(void) |
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{ |
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TCCR0B = (1<<CS02)|(1<<CS00); //Timer clock = system clock / 1024 |
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TIFR0 = 1<<TOV0; //Clear TOV0 clear pending interrupts |
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TIMSK0 = 1<<TOIE0; //Enable Timer0 Overflow Interrupt |
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} |
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void slave_rx(uint8_t* data, int len) |
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{ |
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if (len > 0 && data[0] < FORKLIFT_DATA_LEN) |
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{ |
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internal_index = data[0];
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if (len > 1) |
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{ |
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if (internal_index == FORKLIFT_HEIGHT_SETPOINT)
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{ |
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internal_data[internal_index] = data[1];
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i_term = 0;
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} |
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else if (internal_index == FORKLIFT_LINE_THRESH_HIGH) |
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{ |
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internal_data[internal_index] = data[1];
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line_set_threshold_high(data[1]);
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} |
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else if (internal_index == FORKLIFT_LINE_THRESH_LOW) |
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{ |
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internal_data[internal_index] = data[1];
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line_set_threshold_low(data[1]);
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} |
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} |
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} |
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} |
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void slave_tx(void) |
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{ |
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twi_transmit(&internal_data[internal_index], 1);
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internal_index++; |
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if (internal_index >= FORKLIFT_DATA_LEN)
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internal_index = 0;
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} |
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int clamp(int min, int max, int val) |
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{ |
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if (val > max) return max; |
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if (val < min) return min; |
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return val;
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} |
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SIGNAL(TIMER0_OVF_vect) |
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{ |
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// TODO make this more easily tunable (despite integer limitations)
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int height = (int)internal_data[FORKLIFT_HEIGHT]; |
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error = (int)internal_data[FORKLIFT_HEIGHT_SETPOINT] - height;
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i_term = i_term + error/4;
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int speed = clamp(-127, 127, i_term/12 + error*4); |
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if (height < 15 && speed < 0) speed = 0; |
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if (height > 240 && speed > 0) speed = 0; |
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set_motor(speed); |
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} |
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int main()
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{ |
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int i;
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error = 0;
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i_term = 0;
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init_int0(); |
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sei(); |
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twi_attachSlaveRxEvent(slave_rx); |
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twi_attachSlaveTxEvent(slave_tx); |
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twi_setAddress(TRACKING_ID); |
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twi_init(); |
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analog_init(); |
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motor_init(); |
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while (1) |
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{ |
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for (i = 0; i < 5; i++) |
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internal_data[i + FORKLIFT_LINE_VALS_START] = line_read(i) >> 2;
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internal_data[FORKLIFT_LINE_POS] = line_read_pos(); |
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internal_data[FORKLIFT_HEIGHT] = 255 - (analog_read(ADC_HEIGHT) >> 2); |
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} |
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return 0; |
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} |