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gregoryg
Joined: 21 May 2009
Posts: 14
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| Sun tracking robot |
 Posted: Mon May 25, 2009 6:32 pm |
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Hello, I am working on a sun tracking robot. It moves on a certain path with 3 servo motors and at the same time 2 other servo motors adjust the solar panel in 2-D according to the data from 2 pairs of sensors .
This is a code for the wheels and the panel motors:
compiler 4.057
pic 16f877a
| Code: | #include <16F877A.h>
#fuses HS, NOLVP
#use delay(clock = 20000000)
#define PWM_PIN1 PIN_B1 //wheel 1
#define PWM_PIN2 PIN_B2 //wheel 2
#define PWM_PIN3 PIN_B4 //wheel 3
#define PWM_PIN4 PIN_B3 //motor x
#define PWM_PIN5 PIN_B5 //motor y
#define LOOPCNT 390
static int16 width1,width2,width3,width4,width5;
static int16 loop = LOOPCNT;
static int16 pulse1,pulse2,pulse3,pulse4,pulse5;
//-------------------------------
#INT_RTCC
void tick_interrupt(void);
//==========================================
void main()
{
width1=20; // move left
width2=30; // dont move
width3=40; // move right
setup_counters(RTCC_INTERNAL | RTCC_8_BIT, RTCC_DIV_1); // (20MHz / (256*4*1)) = 20KHz
enable_interrupts(INT_RTCC); // equals 0.05ms per interrupt
enable_interrupts(GLOBAL); // 0.05ms*390 = 19.5ms(almost 20ms)
delay_ms(30000); // move for 30 sec
//-----------------------------------------------------------
width1=40;
width2=20;
width3=30;
delay_ms(30000);
//-----------------------------------------------------------
width1=30;
width2=40;
width3=20;
delay_ms(30000);
}
//====================================
#INT_RTCC
void tick_interrupt(void)
{
static int16 loop = LOOPCNT;
static int16 pulse1,pulse2,pulse3;
if(--loop == 0 )
{
loop = LOOPCNT;
pulse1=width1;
pulse2=width2;
pulse3=width3;
pulse4=width4;
pulse5=width5;
}
if(pulse1)
{
output_high(PWM_PIN1);
pulse1--;
}
else
{
output_low(PWM_PIN1);
}
if(pulse2)
{
output_high(PWM_PIN2);
pulse2--;
}
else
{
output_low(PWM_PIN2);
}
if(pulse3)
{
output_high(PWM_PIN3);
pulse3--;
}
else
{
output_low(PWM_PIN3);
}
if(pulse4)
{
output_high(PWM_PIN4);
pulse4--;
}
else
{
output_low(PWM_PIN4);
}
if(pulse5)
{
output_high(PWM_PIN5);
pulse5--;
}
else
{
output_low(PWM_PIN5);
}
}
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I want the panel to move every 2 seconds to the more lighted side.
I don't want to start writing a code that is not possible, so I wanted to make sure I am in the right direction.
Is it possible to run the A2D code inside second interrupt (TIMER1) every 2 sec and from there to set the direction of the motors?
Thank you.
P.S If you any comments on the code above , please let me know. |
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Ttelmah
Guest
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| Posted: Wed May 27, 2009 9:46 am |
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Realistically, I'd reconsider this approach. The problem is that if (for example), shadows cross the system, you risk the unit moving off alignment, and then not being able to get back...
Instead, model the Sun's motion, with effectively a clock. For a single day, this is a simple sidereal motion. Have your detector, allowed to 'tweak' the clock motion by a small amount only (perhaps 1%), and at the end of the day, the average 'tweak' used during the whole day, is applied to the clock carried forwards. This then will slowly adjust the clock, to prevent it drifting from the real motion. Similarly, the azimuth, should only be tweaked by a small amount, 'day on day', but the correction carried forwards, so that the system will self correct for the seasons. Then have an overall intensity detector, or IR cloud detector, and if the intensity falls below a particular level (or cloud above a similar threshold), ignore the readings from the tracker completely, but just move with the sideral prediction.
Best Wishes |
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