Toltechs success with camera

[Andrew Schuetze]

We achieved a major milestone for our veteran team in getting the camera code working with 1.5 weeks left to program Here is video from Tuesday night without the tilt function on the camera. On Wednesday night, we repeated the performance but this time with the tilt. The development 'bot is from '05.

Posted by D. Sean Kelly on the toltech Wiki
It's not the best video in the world and it may not be the most dramatic display of autonomous robot behavior; but it is working well.
Description: The robot is set to face the general direction of the Rack; probably about 20-25 degrees off the light. When the auto mode starts the robot orients itself toward the light, then starts heading toward it. If it veers off course it will correct mid-way (this is visible in the 2nd half of the clip with the better lighting).
The first run was under optimal lighting (the rack was in a dark area of the shop). The second run we turned on the florescent lights above the rack and ran it again. The robot was able to track the target in both lighting conditions very well.

499 Toltechs Auto One

[Donut]

Looks good, glad to see another team getting the camera driving up and working.

[Brad Voracek]

Very cool, congrats... Hopefully ours looks the same in the near future. Although we were planning on just dead reckoning forward (obviously getting a little slower at the end) and using the light for horizontal adjustment... Although it sounds like you tried that, you like using the camera tilt to adjust speed based on how far you are also? Hm.

[Brandon Holley]

having the robot move towards the light............always a good thing

[Andrew Schuetze]

Originally Posted by Brad Voracek

Very cool, congrats... Hopefully ours looks the same in the near future. Although we were planning on just dead reckoning forward (obviously getting a little slower at the end) and using the light for horizontal adjustment... Although it sounds like you tried that, you like using the camera tilt to adjust speed based on how far you are also? Hm.

We have been using Easy C this year and basically have a group of four students working with two mentors going through the tutorials on the camera. I think at this point the code is using the drive system to only making course corrections to keep the target in the middle of the frame. The plan is to use the tilt angle as feedback for our stopping point. I am not certian if they are slowing the robot down as the tilt angle increases or just stops when it reachs a set angle.

Good luck with your efforts and I hope to see lots of teams driving autonomously this year

[Ianuser]

Please help me, I can't figure out how to use the camera to actually MOVE the robot. I have the camera code working along with the camera itself, but how do I move pwm01 (left drive wheel) and pwm02 (right drive wheel) individually according to the pan of the camera? I have no idea where to begin with this code. (I just got the code to work for the camera and I've been trying for weeks. Now I only have 2 days, Please help if you can)

	
int I_Want_To_Search = 1;
int pwm01_On_Off = 1;
int pwm02_On_Off = 1;
int pwm03_On_Off = 1; //these are all at the top of user_routines.c Everything else is in Processfrom master UP (except TARGETRANGE[] and FIND_DISTANCE())



                          if(I_Want_To_Search == 1)
	{
		Servo_Track();
	}


                          if((Get_Tracking_State() == CAMERA_ON_TARGET) || (Get_Tracking_State() == TARGET_IN_VIEW))
		{
			pwm01_On_Off = 0;
			pwm02_On_Off = 0;
			pwm01 = 230; //Desired Forward Velocity
			pwm02 = 230;
			Switch3_LED = 1;
			
			//printf("2"); //these statements are just to see if it worked
		}
		else
		{
			Switch3_LED = 0;
			pwm01_On_Off = 1;
			pwm02_On_Off = 1;
			//printf("4"); //these statements are just to see if it worked
		}
		/*
		if(Find_Distance() <= 50) //THIS DOESN"T WORK!! WHY NOT?
		{
			pwm01 = 127;
			pwm02 = 127;
			pwm01_On_Off = 1;
			pwm02_On_Off = 1;
			I_Want_To_Search = 0; //Stops calling Servo_Track(). THEN CALL ANOTHER THING
			Switch3_LED = 0;
			//printf("3"); //these statements are just to see if it worked
		}
		*/

		if(p1_y > 129 || p2_y > 129)
		{
			pwm01_On_Off = 1;
			pwm02_On_Off = 1;
		}
		else if(p1_y < 125 || p2_y < 125)
		{
			pwm01_On_Off = 1;
			pwm02_On_Off = 1;
		}

The Find_Distance() function is this:

unsigned int Find_Distance(void)
{	
	return(targetRange[pwm07-144]);
}and target range is this:

const rom unsigned int targetRange[] =
	{
3355,
1676,
1116,
835,
666,
553,
472,
411,
363,
325, //place 10
293,
267,
244,
225, 
208,
193,
179,
167,
156,
146, //place 20
137,
128,
121, 
113, 
107,
100,
94,
89,
83,
78, //place 30
73,
68, 
64,
60,
56,
51,
48,
44,
40,
36, //place 40
33, 
29, 
26,
23,
19,
16,
13,
10,
6,
3, //place 50
0, //place 51
};

So I would like to know why my distance thing isn't working (Max tilt is 194 and min is 94, center at 144. My degree per pwm step was 1.7647 (50/90? is that right?) Then I multiplied that by the pwm index up to 51 and found the radian value and plugged it into TAN(x) and then did 116-12.625(my height)/tan(the radian value from before)) Assuming that's correct, what's wrong with the rest of the code? It's not working properly. Camera looks away from the light when I comment in the Find_Distance code (less than 50 or whatever). ALSO, how do I program the robot to move forward???

[Salik Syed]

Ianuser:
why do you divide 50 by 90?
Degrees/per step = The amount of tilt angle in the camera/ number of PWM steps

The number of steps you have is 51 (194-144) inclusive...

okay never mind, 1.765 is the right number... you just wrote it wrong in the post.

Now are you sure that the camera has a 90 degree range when varying from level (pwm = 144) to fully raised( 194) ? I don't think that is right, but i'm an alumnus, and haven't played with the camera much.

You turn off I_want_to_search when range is <= 50, i'm assuming that sets the PWM values to neutral, that is why the camera looks away.

How to move? The fastest/simplest way is to scale your motor speed to your tilt angle (and thus your distance),
so do something like this:
PWMsout = (194-cameraTiltValue)*Scalar;

[Salik Syed]

.999~(repeating) = x
9.999~ = 10x (Multiply both sides by ten)
9 = 9x (Subtract x, or .999~ from both sides)
Wait a sec... you are assuming x =1, 10 - 1 = 9, not 10 - .999~
That does not follow, you can't use your conclusion, to reach your conclusion!
x = 1 = .999~

[Ianuser]

OK, for the pwm steps, my MIN is 94, max is 194 and center is 144. its a 50º range, 25º from 94 to 144 and 25º from 144 to 194. So, shouldn't it then be 100/50? or what? Im still a bit confused.

ALSO, might this work for moving the robot toward the light?

if((Get_Tracking_State() == CAMERA_ON_TARGET) || (Get_Tracking_State() == TARGET_IN_VIEW))
		{
			pwm01_On_Off = 0;
			pwm02_On_Off = 0;
			Switch3_LED = 1;
                                       if(PAN_SERVO > PAN_CENTER_PWM_DEFAULT)
                                      {
                                           pwm01 = 180;

                                      }
                                      else if(PAN_SERVO < PAN_CENTER_PWM_DEFAULT)
                                      {
                                           pwm02 = 180;
                                      }
                                      else //see below for question
                                      {
                                           pwm01 = 180;
                                           pwm02 = 180;
                                      }                     
                          }

(pwm01_On_Off and pwm02_On_Off are just to map the joystick to the pwm. if 1, then joystick works, if its not 1 (usually 0), then joysticsk dont work and the motors can be set to specific speeds.)

How do I use error precent to manipulate how accurate ("//see below for question") this will be (when it is looking directly at the light)?

[Ianuser]

ALSO, about the pwmstep thing...I can change the MAX and MIN and CENTER in tracking.h, right? (If I do that, do I have to mess around with the pwmvalue per large step which is right now 50...94 to 144 to 194 at 3 steps in total? And do I have to change anything in the CAMERA.C file?) Might that give me a better angle to work with if 94 to 194 is only -25º to 25º?