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puneetverma24
03-25-2011, 09:35 PM
my line follower works at very low speed of motor

How to make it sense lines at faster rate ?
my uc is at89s52 having 11.052mhz crystal oscillator

vikas
03-26-2011, 02:35 AM
Simplest is to buy better stuff -

Light high speed motors,good wheels , better sensors , high power uC and good battries. A dragster like robot design also helps.

On s/w side ... look into PID :)

puneetverma24
03-26-2011, 08:47 AM
which uc & at what rpm of motor should i use ?

allbits
03-26-2011, 12:21 PM
You dont have to sense light at a faster rate. What you need to do is to drive the motors at a faster , less error free rate. A PID control does that. use low weight, High rpm motors and a less heavy battery.

vikas
03-26-2011, 01:01 PM
I had written a small article on competition robotics if on a budget use the items suggested there ... you will have a robot capable of beating most indian line followers.

But if you wish to compete internationally you need to look into maxon motors and dragster like designs ... lots of videos on youtube.

kawal24
03-27-2011, 02:09 AM
The main thing to be considered for fast line follower is the sensor.
You can get high rpm motors at a cheap rate but if you want to follow the line at a high speed of your robot you will need some good sensors that are capable of detecting line at a high speed with minimum(negligible) errors.and yeah this sensors cost more.
If you are using phototransistors(LDR) for sensing light then it may be quite hard.

vikas
03-27-2011, 02:24 AM
The main thing to be considered for fast line follower is the sensor.
You can get high rpm motors at a cheap rate but if you want to follow the line at a high speed of your robot you will need some good sensors that are capable of detecting line at a high speed with minimum(negligible) errors.and yeah this sensors cost more.
If you are using phototransistors(LDR) for sensing light then it may be quite hard.

Dont mind , You have no idea what you are talking about ... there is a WHOLE LOT MORE to making things go fast under control .

kawal24
03-27-2011, 02:51 AM
Dont mind , You have no idea what you are talking about ... there is a WHOLE LOT MORE to making things go fast under control .

I know that there are WHOLE LOT MORE to makings things go fast but one of the important aspects of a fast line follower robot is a sensor.I had made a line follower robot with 204:1 gear ratio motor using LDR and LED it worked fine because the rpm was about 60 to 75 rpm.But when i changed the motor gear ratio to 58:1(high rpm) the robot was not able to follow line properly using LDR.It would miss the line sometime near turns.
Then i replaced the LDRs with the line following sensor(especially built for) and it worked well.

and yeah i also tried the trick of slowing down the robot using PWM function just before the turn and it worked quite well.

allbits
03-28-2011, 11:01 AM
Then i replaced the LDRs with the line following sensor(especially built for) and it worked well.


Not true.
Never underestimate the LDR. Reason why people fail to build line followers with LDR is that, they do not know how to use the LDR properly.

Coming to the point, just replacing your line follower sensors with expensive ones will not speed up your robot. It is all about how you use the sensor, and how you calculate error. it is very much possible to make decent line followers with the Rs 5 IR pair available or the Rs 5 LDR. Here, the algorithm is important.

Going to high end competitions, what you need is optimization in everything. The center of gravity, inertia, weight of the robot, diameter of wheels, the motors, the sensors - all come into picture. The catch is to use the best combination of components for your algorithm. And for this, you need years of experience, which you will get only from building more and more robots.

Just make a robot, which can go straight with your required speed. Try to build one which moves 1.5m/second, straight. No need to worry about curves. If you cannot build one which goes straight with your required speed, you cannot build one which can turn.

hotshot05
04-04-2011, 03:01 AM
I have a question - Is it better to use a simple 100RPM DC motor for line following purpose or will it be better if I use a stepper motor?

I know that the programming will be much more complicated if I use a stepper motor but wont I get a very fine control while taking turns?

allbits
04-04-2011, 10:50 AM
Use a DC motor. Actually, DC motors are smoother than Stepper motors.

hotshot05
04-05-2011, 02:00 AM
But while turning, wont we need the precise control over the turning angle?

allbits
04-05-2011, 05:20 PM
Precise control is required in going straight as well. Either ways, DC motor is better.