Reverse mower-motor direction doesn't work

[alexvaut]

Behavior:
sometimes it feels the robot is not mowing anything.

Test:
I made several tests where I enable/disable mowing and I change the direction

1. (normal) rosservice call mower_service/mow_enabled 1 1
2. (reverse) rosservice call mower_service/mow_enabled 1 0
3. (stand-by) rosservice call mower_service/mow_enabled 0 0

Normal state 1 works very well, the motor is consuming close to 1A and the motor speed is quite high.
Reverse state 2 doesn't work well at all.

• After a stand-by, it turns but very slowly and it's not making much sound.
• After a normal state, motor is stopped.

The problem is coming from : #43

[Apehaenger]

Switching the motor direction to opposite direction at full speed sound risky! (Did you also tried it with your car? ;-))

I guess you've tested with xESC2-mini (STM based ESC)?
Because: STM based xESC has much better over-current- protection.
In the case of xESC-2040 you may kill the MOSFETs on first try.

Please try again, but stopping before:

1. (normal) rosservice call mower_service/mow_enabled 1 1
2. (stop) rosservice call mower_service/mow_enabled 0 0 (and wait 2-3 seconds)
3. (reverse) rosservice call mower_service/mow_enabled 1 0
4. (stop) rosservice call mower_service/mow_enabled 0 0

[alexvaut]

This is what I tried at the beginning but I got the same results, it was always super slow on reverse. Note that I came to use the mower_service after the robot didn't mow. So if the electronic is fired somehow, it happens by the ros code.

[ClemensElflein]

Interesting, the mowing motor and the ESCs don't really have a "direction", so it's weird that it behaves differently when switching directions.

The ROS code can't fry electronics by itself, it just tells the motor controller "go at x% speed clockwise / anti-clockwise", both of which should be safe options to send. The speed controller does the actual switching of the MOSFETs.

Which robot and motor controllers are you using?

[alexvaut]

Original mower is a yardforce 500B and I received the full electronic kit 2 weeks ago.

[Apehaenger]

How's about checking if it's the ESC, by exchanging with one of your drive ESC's?
Probably more complicated as you need to load the mower-config to the drive ESC via VESC tool?!

In the case that you already assembled your mowers cover, you may temporary hardcode your working direction here (till you need to open it anyways):

open_mower_ros/src/mower_logic/src/mower_logic/mower_logic.cpp

Line 246 in e98f018

mow_srv.request.mow_direction = started.sec & 0x1; // Randomize mower direction on second

via mow_srv.request.mow_direction = 1

[alexvaut]

@Apehaenger I never played with ESC yet. I'm currently testing that branch where I made the random direction configurable: 4ed8e79

[alexvaut]

I confirm it was a wrong ESC setup, the 3 ESC on the main board were configured the same when I received them. I didn't check. Now that the mower motor config has been configured on TTYAMA3, I realise that it's much more powerfull even in the "normal" direction ! And the reverse seems to work as well very well. But, I still recommend this PR to make it optional.

[Apehaenger]

Quite thanks for being that plain!!
Thought about it the last days, but couldn't imagine what's wrong with it.
Now I can kick it out of my brain ;-)

[michifischer]

I confirm it was a wrong ESC setup, the 3 ESC on the main board were configured the same when I received them. I didn't check. Now that the mower motor config has been configured on TTYAMA3, I realise that it's much more powerfull even in the "normal" direction ! And the reverse seems to work as well very well. But, I still recommend this PR to make it optional.

How did you check the configuration of the ESCs? Which config files did you use in the end and how did you update it?

[alexvaut]

@michifischer I just use this doc: https://github.com/ClemensElflein/openmower.de/pull/26/files

[michifischer]

Thanks!

I got the upgrade kit last week, too. I can confirm that the configuration for the mower motor driver was not working well - you could barely hear the mower motor and the motor current did not exceed 250mA. The mowing result was not satisfying. After updating the mower motor config the mower works fine with a motor current of about 1A.