Dobot Magician Homing drives past end of travel


#1

When I press the home button it goes through a range of motions, but for one of the joints it drives to its end and then continues to try and keep going making a jumping/ grinding noise. The only way to stop it is to Emergency Stop. Then the only option is to taskkill the software as you loose control of the software.

I have tried updating the software but the update option hangs after it finishes downloading 3rd Party Tools and it never moves onto downloading the latest version of DobotStudio. I can’t download the latest software from the web either because you cant create an account on https://en.dobot.cn because you never receive the email verification code.

Any suggestions of how this can be fixed?

Regards
Warren.


#2

Hi, you can try setting its homing point to (250, 0, 0, 0). I also didn’t get the verification email when I signed up for the account, I emailed the website technician(dingshihao@dobot.cc) and he helped me with the manual verification, so I successfully created the account.


#3

Hello, how is the thing going on now? Have the problem been solved?


#4

Hi Ryan,

Thanks for your help. Setting the position of home to (250,0,0,0) did stop the issue of it trying to drive past its vertical limit when pressing the home button.

But this didn’t fix the actual problem of the back arm trying to go past the vertical physical limit (say when pressing J2-). However I have since worked out how to fix this problem. Initially I didn’t realise the position of the arms was initialised by an angle sensing devices in the arms themselves. Knowing that the stepper motors had no absolute position measuring device I thought it would drive to a limit switch to find the home position and initialise from there, I found this out by accident when I accidental moved the device while the homing process was executing and I then realised that if you leaned the robot over while homing it would adjust the arm to stay at the same angle relative to gravity. Once I had worked this out, I then went searching for settings and found Settings:-> Sensor and Base:-> Rear Arm Angle Sensor Zero Error.

After playing with this setting, I found setting this to a large negative value stopped it trying to drive past its vertical physical end stop. Ultimately I adjusted the value so that when the rear arm was exactly vertical the angle sensor measured exactly 0 degrees. NB: For me I had to set this to -11.86, but this probably varies from machine to machine.
Now if I manually drive the rear arm up (with J2-) it will stop on a soft limit of -5 degrees which is before it physically runs out of travel. Problem fixed.

On the account issue I haven’t had a change to send that email yet. Once I got past the end stop issue I wasn’t so concerned about the issue of trying to get the latest version of software.

I hope this information helps other people that run into the same issue.


#5

Hello Warren, thanks for sharing the information, it will be helpful for other users.


#6

Been looking for this answer for a couple years now for my OG Magician. I don’t know how I missed this topic so many times.
The settings don’t seem to get saved though. I have to re-enter the values in settings every time I open the software. Is there a way to save the adjustments?