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Increasing the rate of turning when sonar trigger.

M

max@birley_com

Member
Hi
I am using PCB 1.3 with an Arduino mega. Also I am using chassis mini with small 4 * 12 volt motors. This chassis is a little difficult to turn due to the wide tires. These will be changed.

Most options in pfod are turned off (battery, perimeter, imu, etc, etc) except one central sonar detector. This is working as expected, however when the mini stops for an object it take 10 goes back an forward to get around the obstacle. What do I need to do to make sharper and faster turns.

Are all the parameters for this in mower or are they elsewhere

In mower on pfod I do not understand the L and R motor calibration. The slider is moved to the right and then it displays numbers as the slider moves to the left. then some number is written to a file. the values in config file motor SenseScale what do they mean, should they be similar for each motor?

how to use testing in pofd

I do not understand Accel? what is a good range

what is happening if overload counter is tripped

I have the max ppm set at 127 should this be increased

are they other ares of the code that control the movement of the mower

regards

Max
 
I have been using the setup mentioned above mainly inside on carpet. When used with RC I can drive it around easily and it has reasonable power for a smallish rover.
however today I took it out on the grass and the motor counters keep on triggering even in manual.
I tried increasing the power (watts) from 36 to 100 (in stages) and the calibration from 250, 500 to 1000 and the chassis still keeps on triggering the motor counter.

I would be very grateful if someone can help me to understand all the parameters that effect the output of the motors in order to stop the motor triggering.

I imagine that the physical motors them selves the selected ppm of the motors, the selected motor calibrations, the selected power all effect the possibility of a trigger event. What about ACCEL? are there others. what combination should I use to give the rover more power to the motors
regards
Max
 
Hi.
In the setup you use mini or ardumower ?
Did you use Odometry?
Can you use pfod or arduremote to verify the motor and odometry parameter.
What version of azurit ?
You need to verify the motorsense in real time using the console to be sure the value are correct .

ACCEL is exactly acceleration time and breaking if no odometry is used.
 
Dear Bernard
Thanks for answering as this is driving me crazy
I am using mini
I have encoders fitted on 2 of the 4 motors, however odometers is turned off for now to keep everything simple
Yes I can use either pfod or arduremote to change the parameters. I have tried multiple combination of power watts, calibration, pwm, etc etc and still the motors trip with a error. Usually what I do is raise up the mini and put is on a block and let it run free. Then progressively apply some pressure to slow the wheels and obverse the current and the watts consumed in pfod. As I do apply pressure to slow the wheels the watts increases. If I press too hard and the watts goes above watts* calibtation the motors trip.
Even if this is working well on the bench when I put the mini on the ground it may work well going forward then trip in reverse.
Then when I put it on the grass it will trip even though the mini with a normal sabertooth motor controller will easily move the mini on the grass

If I can not fix this then I can not progress

Can you give me an idea of what to look for on the console re motorsens to get a better understanding and to solve this issue

Regards
 
Don't know the mini but if i remenber:
with Pfod in Info try to change the Developper to YES.
After that when you go into setting motor at the end of the page you can change the left and right motorsensescale.

Try to set a value matching the real sense in ma the motor use when you read it with a multimeter.
Verify the max power of your motor and set the value in maxpower.

Hope it's can work.
 
Dear Bernard
Many thanks, seems to be much better. Changed to developer reduced power and set Motorsenseleftscale and right and the motors are now not tripping

do you know what the calibration left motor and calibrate right motor does exactly

So I re connected the sonar and the mini is stopping. It also reverses. However the ROLL state that tries to turn the the mini not really working. What parameters will make the ROLL (or turn) more aggressive

have a nice weekend

Max
 
Hi.
You can set the developer to NO when the setting are OK.
But in all case there are motor protection problem with a 4WD configuration and WHY 4WD ??.
For a good motor protection the driver need to control the sense of only one motor
I suppose you connect two motor in parallele and what the matter if you manualy block one motor ?????? (maybe you can burn it while the other drain the current and false the reading of the driver sense.).
I do not understand the L and R motor calibration
Zum Vergrößern anklicken....
What you see with this 2 slider is a 5% smoothed value of the reading sense (to avoid big variation in reading)
In the code it's this line, be carreful that accel is different than Accel=1000.

double accel = 0.05;
motorRightSenseCurrent = motorRightSenseCurrent * (1.0-accel) + ((double)motorRightSenseADC) * motorSenseRightScale * accel;


Code: 
the ROLL (or turn) more aggressive


You say PPM but i suppose it's PWM and yes for more power you can increase this value up to 255 and the RPM value also.

BUT 4WD NEED TO BE CARREFUL WITH THE SENSE OF 4 MOTOR ??
 
Hi Bernard
Nice answer. You are really helpful. This subject is difficult but fun
I will move from a 4wd to a 2wd chassis to avoid the problems you mentioned.

Currently I am happy with the speed of my mini (4wd)
If I increase pwm the speed also increases. However I want to increase the aggressiveness of the turn (Roll) without increasing overall speed as I am using the mini in doors and do not want it going too fast
Can this be done or do I need to change to 2wd now
 
Hi.
As i tell you i don't know the Mini version but your main problem is the low speed and low PWM (127) so low torque on the motor.
I think your motor have a max torque at 12V PWM=255 so the only solution is to reduce the final speed for exemple by reduce the Wheel diameter.

A perfect working condition is to have a PWM value between 200 and 230 when the mini go at the wanted speed

I thing it's better for the motor to change to 2WD.
Good Week end.
 
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