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Topic: Autonomous Robot, motor driver (Read 3 times) previous topic - next topic

husein06

Feb 22, 2013, 05:42 pm Last Edit: Feb 22, 2013, 06:14 pm by husein06 Reason: 1
Hello all,

So, long story short, I made an autonomous robot.

2 Problems: Wont drive when put on the ground and everything shuts down when not using CPU power.

My robot works perfectly when not put on any surface, the wheels are spinning very well, then the first time I tried it on a surface it worked for 10 seconds only, then after that every-time I put the robot on any floor surface it can't drive, then I lift it it works fine, and so on. My robot all together only weighs 4lbs.
Using a 7.2V rechargeable Battery
Motors: Motor Ratings (at 7.2 VDC):
No-load Current: 0.27 A @ 310 RPM
Stall Current: 4.8 A
Max Torque: 4.6 lb-inch (5.3 kg-cm)

Motor Driver:
Operating voltage: 5-28 V
Maximum PWM frequency: 10 kHz
Current sense: 0.59 V/A
Time to overheat at 5 A*: 2 s
Time to overheat at 4 A*: 21 s
Time to overheat at 3 A*: 165 s
Current for infinite run time*: 2.5 A

What seems to be the problem, wrong motor driver, motors too weak?

HazardsMind

What you using to power it on the ground?
Created Libraries:
TFT_Extension, OneWireKeypad, SerialServo, (UPD)WiiClassicController, VWID

husein06


What you using to power it on the ground?

Using a 7.2V rechargeable Battery for the motors, and arduino 9v and laptop cord for the rest of the project, but the main problem is the motors spin perfectly when not on the ground.

JimboZA

It might be a simple mechanical problem to do with (lack of) gearing.

Have you got a motor driver chip in the mix somewhere though?- if you have say a 298 in there you'll be losing volts at the best of times but even more if the current is high with a motor trying to get the robot started. What's the voltage at the motors?
Roy from ITCrowd: Have you tried turning it off an on again?
I'm on LinkedIn: http://www.linkedin.com/in/jimbrownza

HazardsMind

Your motors probably dont have enough torque, in which case you will some kind of gear system.
Created Libraries:
TFT_Extension, OneWireKeypad, SerialServo, (UPD)WiiClassicController, VWID

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