[Dprglist] (no subject)

David Anderson davida at smu.edu
Thu Apr 30 13:36:24 PDT 2020


Cool.  Especially the force sensing gripper.  Any pics or video?

I played with Roborealm some (many) years ago but didn't pursue it 
seriously at the time.  A couple of the guys in the group use lidar for 
localization for some of the robot contest courses though I'm not sure 
they use it for more real-world environments. Contest courses are easy :)

I've had pretty good success with a generalized version of wall 
following which I call perimeter following (i.e., doesn't require a nice 
flat wall) to do room navigation.   The robot also runs location 
calculations at 20Hz using gyro corrected odometry while perimeter 
following so it knows where it is and can, for example, stop when it 
gets back to the starting point, as you suggest.

Here's a video of the two-wheel balancing robot nbot doing some 
perimeter following in the basement of the Heroy building at SMU where I 
work, which is a pretty challenging environment:

http://www.geology.smu.edu/dpa-www/robo/nbot/20120614_nbot_05b.mpg

regards

dpa



On 04/30/2020 12:58 PM, Robert Zeiler wrote:
> Thanks I've been thinking about the left or right wall rule. Yes, 
> Herbert started out as a LEAF robot. I've gone further than the group 
> though. The last addition to Herbert was an arm with several DOF and a 
> force sensing gripper. Had to learn a lot about torque and gear and 
> chain drives.
> Have you had any success using LIDAR or programs like Roborealm. 
> (Herbert uses Roborealm for some things).
>
> Robert
>
> On Thu, Apr 30, 2020 at 10:16 AM David Anderson via DPRGlist 
> <dprglist at lists.dprg.org <mailto:dprglist at lists.dprg.org>> wrote:
>
>     Robert,
>
>     Sounds like what you are looking for is SLAM.   Though from your
>     description perimeter following would probably work and be much
>     more robust.  Is Herbert one of the LEAF robots?
>
>     regards
>
>     dpa
>
>
>
>     On 04/30/2020 11:50 AM, Robert Zeiler via DPRGlist wrote:
>>     Hi all
>>     Thanks for the reply.  I have also done odometry on my robots as
>>     well as ultrasound and IR.
>>     But, for this application, I was looking for experience with
>>     either visual or lidar mapping techniques. Basically the idea is
>>     for the robot to enter a room, scan the environment for obstacles
>>     (will also have onboard sonar for collision avoidance), make a
>>     map from the readouts and then enter the room using the info to
>>     establish a path through the room.  I want to hit all areas of
>>     the room. The robot will return to the starting point and stop.
>>
>>     Robert
>>
>>     On Wed, Apr 29, 2020 at 5:22 PM Murray Altheim via DPRGlist
>>     <dprglist at lists.dprg.org <mailto:dprglist at lists.dprg.org>> wrote:
>>
>>         Hi Robert,
>>
>>         I'm also keen to understand how to perform some of the tricks
>>         David has
>>         perfected, and it's worth mentioning that he has a helpful
>>         page on
>>         odometry at:
>>
>>         http://www.geology.smu.edu/~dpa-www/robo/Encoder/imu_odo/
>>         <http://www.geology.smu.edu/%7Edpa-www/robo/Encoder/imu_odo/>
>>
>>         As my robots are all targeted at indoors GPS is unavailable.
>>
>>         I've put together the beginnings of a page on the NZPRG wiki
>>         on the
>>         subject at:
>>
>>         https://service.robots.org.nz/wiki/Wiki.jsp?page=Odometry
>>
>>         but it's not had much love (yet) as I'm still getting my PID
>>         controller
>>         to the point of functionality (and not being sidetracked by
>>         every other
>>         whim that comes my way, such as Firmata).
>>
>>         I've also considered having my robot perform repeated scans
>>         of the signal
>>         strength of all the WiFi signals it can see (dozens, in a
>>         suburban
>>         neighborhood) from the four corners of my house, storing that
>>         information,
>>         and using that info, along with compass heading (from a
>>         BNO055) to get an
>>         idea where in my house the robot is. Since the Raspberry Pi
>>         has WiFi built
>>         in, this is a free exercise (no additional sensors required).
>>         There's a
>>         lot of noise, you'll need both a blacklist (because cell
>>         phones move
>>         around) and a whitelist (to prioritise known sources as if
>>         they were
>>         beacons, or actually use a few older Pis as beacons), but I'm
>>         still
>>         thinking it might work...
>>
>>         Cheers,
>>
>>         Murray
>>
>>         On 30/04/20 12:07 pm, David Anderson via DPRGlist wrote:
>>         > Robert (and Herbert)
>>         >
>>         > I've been doing autonomous robot navigation successfully
>>         for some years now using location information gathered from
>>         wheel encoders and gyros on a number of my robots.  I'd be
>>         happy to answer any questions you might have.  You might start
>>         > out by looking at the navigation writeups associated with
>>         my outdoor jBot robot:
>>         >
>>         > http://www.geology.smu.edu/dpa-www/robo/jbot
>>         >
>>         > Here's a video of that robot navigating through the woods
>>         to a waypoint 500 feet away and returning to within a few
>>         inches of the starting point:
>>         >
>>         >
>>         http://www.geology.smu.edu/~dpa-www/robo/jbot/jbot_hatrick2_2.mpg
>>         <http://www.geology.smu.edu/%7Edpa-www/robo/jbot/jbot_hatrick2_2.mpg>
>>         >
>>         > The jBot robot has an onboard GPS but that is not used or
>>         required for these navigation tasks.
>>         >
>>         > best regards,
>>         >
>>         > dpa
>>         >
>>         > On 04/29/2020 06:37 PM, Robert Zeiler via DPRGlist wrote:
>>         >> Has anybody had any success using any kind of mapping
>>         system or device for robot autonomous navigation?.
>>         >>
>>         >> Robert and Herbert (the robot)
>>         ...........................................................................
>>         Murray Altheim <murray18 at altheim dot com>                
>>            = =  ===
>>         http://www.altheim.com/murray/                              
>>              ===  ===
>>                       = =  ===
>>              In the evening
>>              The rice leaves in the garden
>>              Rustle in the autumn wind
>>              That blows through my reed hut.
>>                     -- Minamoto no Tsunenobu
>>
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>>
>>
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