Hello
I have spent countless hours on my project and i am now out of ideas and energy. I am trying to achieve true torque control (aka current control) which is done (as i understand it) by sampling the amount of current that runs in the system and using that as the Input-parameter of the PID algorithm.
The system consists of the following:
pancakemotor: http://www.pml.com.cn/ver2en/motors/GPM16LR.html
Motorboard: http://www.robotshop.com/eu/en/devantech-md03-50v-20a-h-bridge-driver.html
Ampsensor: http://www.panucatt.com/product_p/cs-50a.htm
Arduino Uno
Pot for setpoint adjustment.
I have a setup similar to this:
http://www.youtube.com/watch?feature=player_embedded&v=_srzYeJi5yo
There is one funny (read terrible) but interesting response of the system. If i apply a steady low output (without PID, just a steady PWM) from the arduino to the motor board the spring will tighten but after a few seconds the motor begins to make a little audible noise. Thats not the problem, but once in a while it is as if the motor looses power for an instant - the duration of the "hole" is very short, only enough to make the motor rotate opposite the pulling direction for a few (15-20) degrees, then the motor re-energizes. My first guess was that it was the motor board is going into over-current protection (a feature it has to not burn out) due to the varying and very low resistance at certain rotor-positions, and the very low inductance (<100uH) of this kind of motor. I have looked at the PWM on a oscilloscope and it does not seem to change accordingly when the motor looses power.
So i have a motor that seems to get a constant PWM voltage but occasionally looses power for (less than) a split second. ????!!!!!!????? Anyone?
I am running PWM @ 32kHz
PLEASE..........ANYONE i am out of things (and forums) to try.
Thank you.
I have spent countless hours on my project and i am now out of ideas and energy. I am trying to achieve true torque control (aka current control) which is done (as i understand it) by sampling the amount of current that runs in the system and using that as the Input-parameter of the PID algorithm.
The system consists of the following:
pancakemotor: http://www.pml.com.cn/ver2en/motors/GPM16LR.html
Motorboard: http://www.robotshop.com/eu/en/devantech-md03-50v-20a-h-bridge-driver.html
Ampsensor: http://www.panucatt.com/product_p/cs-50a.htm
Arduino Uno
Pot for setpoint adjustment.
I have a setup similar to this:
http://www.youtube.com/watch?feature=player_embedded&v=_srzYeJi5yo
There is one funny (read terrible) but interesting response of the system. If i apply a steady low output (without PID, just a steady PWM) from the arduino to the motor board the spring will tighten but after a few seconds the motor begins to make a little audible noise. Thats not the problem, but once in a while it is as if the motor looses power for an instant - the duration of the "hole" is very short, only enough to make the motor rotate opposite the pulling direction for a few (15-20) degrees, then the motor re-energizes. My first guess was that it was the motor board is going into over-current protection (a feature it has to not burn out) due to the varying and very low resistance at certain rotor-positions, and the very low inductance (<100uH) of this kind of motor. I have looked at the PWM on a oscilloscope and it does not seem to change accordingly when the motor looses power.
So i have a motor that seems to get a constant PWM voltage but occasionally looses power for (less than) a split second. ????!!!!!!????? Anyone?
I am running PWM @ 32kHz
PLEASE..........ANYONE i am out of things (and forums) to try.
Thank you.