LukeWarm Show full post »
squishy
"Education is not about filling buckets; it is lighting fires." W.B. Yeats

http://www.youtube.com/user/squishy654
Quote 0 0
eslamessam
hello
this my frist post i have a kit of lulin 30A ESC and arduino mega 2560 & ST2212-1150kv brushless motor
so when i give them pwm at 60% three of the motors runs but the fourth doesn't
while at the 80% all motor run but the last motor speed is equal to others at 60% so
the quad turnover .
Quote 0 0
iamdenis
Hello Luke,

I was wondering if you could give me a hint on controlling the position of a Brushless motor (with an ESC).

If I use an ESC, I only have 1 output from the board. Would it be possible to control how much the motor rotates if i send say, a sine way from [0, pi/3]?

Just to clarify, I am not looking to put out a continuous PWM signal to control the speed, but rather a section of a signal in order to move the motor __ many rads.
Is this possible?

Thank you for the help,
Denis
Quote 0 0
squishy
Quote:
Hello Luke,

I was wondering if you could give me a hint on controlling the position of a Brushless motor (with an ESC).

If I use an ESC, I only have 1 output from the board. Would it be possible to control how much the motor rotates if i send say, a sine way from [0, pi/3]?

Just to clarify, I am not looking to put out a continuous PWM signal to control the speed, but rather a section of a signal in order to move the motor __ many rads.
Is this possible?

Thank you for the help,
Denis


"Education is not about filling buckets; it is lighting fires." W.B. Yeats

http://www.youtube.com/user/squishy654
Quote 0 0
iamdenis
Quote:

That is a stepper motor though.. They have a per-defined number of steps which does not allow for accurate control. They are also much heavier.

-Denis
Quote 0 0
LukeWarm
Quote:
hello
this my frist post i have a kit of lulin 30A ESC and arduino mega 2560 & ST2212-1150kv brushless motor
so when i give them pwm at 60% three of the motors runs but the fourth doesn't
while at the 80% all motor run but the last motor speed is equal to others at 60% so
the quad turnover .
You have a problem in your system that is causing this lack of equality, this is easy to troubleshoot.

    • Some ESCs or mother boards have adjustment pods on them, if your does, follow the adjustment instructions in the manual. If yours does not or this did not fix the problem, read on.
    • Try moving two of the motors to different positions, if the motor is bad, the problem will follow the motor. If nothing changed, read on.
    • Most quads have the ESC built into the mother board. If yours does, the mother board is bad. If the ESCs are separate, read on.
    • If the ESCs are not built into the mother board, try moving two of the ESCs to different positions, if an ESC is bad, the problem will follow the ESC. If the problem did not follow the ESC, the mother board is bad.


To sum it up, you say you have a problem arm. If you have eliminated calibration issues, switch components from the bad arm to a known good arm till you find the problem. Good luck.
Quote 0 0
LukeWarm
Quote:
Hello Luke,

I was wondering if you could give me a hint on controlling the position of a Brushless motor (with an ESC).

If I use an ESC, I only have 1 output from the board. Would it be possible to control how much the motor rotates if i send say, a sine way from [0, pi/3]?

Just to clarify, I am not looking to put out a continuous PWM signal to control the speed, but rather a section of a signal in order to move the motor __ many rads.
Is this possible?

Thank you for the help,
Denis
No. The ESC has no prevision to feel or synchronize to the position of the motor.

I have worked with stepper motors. Each time the system is tuned on, the stepper motor and its controller must find and synchronize to its reference sensor first before it will know where its usable preprogramed positions are. They are used in copiers and scanners to control the scanner arm positions and speeds. The speeds are controlled for document reduction and enlargement purposes. The positions are controlled so the scanner arm knows the start stop and return points. Its reference sensor is at the scanner arm's home position.

The AC motor and ESC that are used in most RC car and trucks use a system similar to a stepper motor so that the speed is more controllable. The big difference is, the RC car motor never synchronizes to a reference position. So it too is unusable for this.
Quote 0 0
squishy
Quote:
hello
this my frist post i have a kit of lulin 30A ESC and arduino mega 2560 & ST2212-1150kv brushless motor
so when i give them pwm at 60% three of the motors runs but the fourth doesn't
while at the 80% all motor run but the last motor speed is equal to others at 60% so
the quad turnover .


This is a classic calibration issue, all ESC's on a multirotor need to be calibrated independently by the throttle channel alone, apart from the flight controller, do each ESC individually them plug them all together into the controller and test.
"Education is not about filling buckets; it is lighting fires." W.B. Yeats

http://www.youtube.com/user/squishy654
Quote 1 0