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    <p>Cool.  Especially the force sensing gripper.  Any pics or video?</p>
    <p>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 :)<br>
    </p>
    <p>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. <br>
    </p>
    <p>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:<br>
    </p>
    <p>
      <a class="moz-txt-link-freetext" href="http://www.geology.smu.edu/dpa-www/robo/nbot/20120614_nbot_05b.mpg">http://www.geology.smu.edu/dpa-www/robo/nbot/20120614_nbot_05b.mpg</a><br>
    </p>
    <p>regards</p>
    <p>dpa</p>
    <p><br>
    </p>
    <br>
    <div class="moz-cite-prefix">On 04/30/2020 12:58 PM, Robert Zeiler
      wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAEpDUR8P7+6cKBhOM7daRA3hNJm=nTBLpY3Y6gvpfeUCHCSuFQ@mail.gmail.com">
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        <div class="gmail_default" style="font-size:small">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. </div>
        <div class="gmail_default" style="font-size:small">Have you had
          any success using LIDAR or programs like Roborealm. (Herbert
          uses Roborealm for some things).  </div>
        <div class="gmail_default" style="font-size:small"><br>
        </div>
        <div class="gmail_default" style="font-size:small">Robert</div>
      </div>
      <br>
      <div class="gmail_quote">
        <div dir="ltr" class="gmail_attr">On Thu, Apr 30, 2020 at 10:16
          AM David Anderson via DPRGlist <<a
            href="mailto:dprglist@lists.dprg.org" moz-do-not-send="true">dprglist@lists.dprg.org</a>>
          wrote:<br>
        </div>
        <blockquote class="gmail_quote" style="margin:0px 0px 0px
          0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
          <div bgcolor="#FFFFFF">
            <p>Robert,</p>
            <p>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?  <br>
            </p>
            <p>regards</p>
            <p>dpa</p>
            <p><br>
            </p>
            <br>
            <div>On 04/30/2020 11:50 AM, Robert Zeiler via DPRGlist
              wrote:<br>
            </div>
            <blockquote type="cite">
              <div dir="ltr">
                <div class="gmail_default" style="font-size:small">Hi
                  all</div>
                <div class="gmail_default" style="font-size:small">Thanks
                  for the reply.  I have also done odometry on my robots
                  as well as ultrasound and IR.</div>
                <div class="gmail_default" style="font-size:small">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.</div>
                <div class="gmail_default" style="font-size:small"><br>
                </div>
                <div class="gmail_default" style="font-size:small">Robert</div>
              </div>
              <br>
              <div class="gmail_quote">
                <div dir="ltr" class="gmail_attr">On Wed, Apr 29, 2020
                  at 5:22 PM Murray Altheim via DPRGlist <<a
                    href="mailto:dprglist@lists.dprg.org"
                    target="_blank" moz-do-not-send="true">dprglist@lists.dprg.org</a>>
                  wrote:<br>
                </div>
                <blockquote class="gmail_quote" style="margin:0px 0px
                  0px 0.8ex;border-left:1px solid
                  rgb(204,204,204);padding-left:1ex">Hi Robert,<br>
                  <br>
                  I'm also keen to understand how to perform some of the
                  tricks David has<br>
                  perfected, and it's worth mentioning that he has a
                  helpful page on<br>
                  odometry at:<br>
                  <br>
                     <a
                    href="http://www.geology.smu.edu/%7Edpa-www/robo/Encoder/imu_odo/"
                    rel="noreferrer" target="_blank"
                    moz-do-not-send="true">http://www.geology.smu.edu/~dpa-www/robo/Encoder/imu_odo/</a><br>
                  <br>
                  As my robots are all targeted at indoors GPS is
                  unavailable.<br>
                  <br>
                  I've put together the beginnings of a page on the
                  NZPRG wiki on the<br>
                  subject at:<br>
                  <br>
                     <a
                    href="https://service.robots.org.nz/wiki/Wiki.jsp?page=Odometry"
                    rel="noreferrer" target="_blank"
                    moz-do-not-send="true">https://service.robots.org.nz/wiki/Wiki.jsp?page=Odometry</a><br>
                  <br>
                  but it's not had much love (yet) as I'm still getting
                  my PID controller<br>
                  to the point of functionality (and not being
                  sidetracked by every other<br>
                  whim that comes my way, such as Firmata).<br>
                  <br>
                  I've also considered having my robot perform repeated
                  scans of the signal<br>
                  strength of all the WiFi signals it can see (dozens,
                  in a suburban<br>
                  neighborhood) from the four corners of my house,
                  storing that information,<br>
                  and using that info, along with compass heading (from
                  a BNO055) to get an<br>
                  idea where in my house the robot is. Since the
                  Raspberry Pi has WiFi built<br>
                  in, this is a free exercise (no additional sensors
                  required). There's a<br>
                  lot of noise, you'll need both a blacklist (because
                  cell phones move<br>
                  around) and a whitelist (to prioritise known sources
                  as if they were<br>
                  beacons, or actually use a few older Pis as beacons),
                  but I'm still<br>
                  thinking it might work...<br>
                  <br>
                  Cheers,<br>
                  <br>
                  Murray<br>
                  <br>
                  On 30/04/20 12:07 pm, David Anderson via DPRGlist
                  wrote:<br>
                  > Robert (and Herbert)<br>
                  > <br>
                  > 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 <br>
                  > out by looking at the navigation writeups
                  associated with my outdoor jBot robot:<br>
                  > <br>
                  > <a
                    href="http://www.geology.smu.edu/dpa-www/robo/jbot"
                    rel="noreferrer" target="_blank"
                    moz-do-not-send="true">http://www.geology.smu.edu/dpa-www/robo/jbot</a><br>
                  > <br>
                  > 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:<br>
                  > <br>
                  > <a
href="http://www.geology.smu.edu/%7Edpa-www/robo/jbot/jbot_hatrick2_2.mpg"
                    rel="noreferrer" target="_blank"
                    moz-do-not-send="true">http://www.geology.smu.edu/~dpa-www/robo/jbot/jbot_hatrick2_2.mpg</a><br>
                  > <br>
                  > The jBot robot has an onboard GPS but that is not
                  used or required for these navigation tasks.<br>
                  > <br>
                  > best regards,<br>
                  > <br>
                  > dpa<br>
                  > <br>
                  > On 04/29/2020 06:37 PM, Robert Zeiler via
                  DPRGlist wrote:<br>
                  >> Has anybody had any success using any kind of
                  mapping system or device for robot autonomous
                  navigation?.<br>
                  >><br>
                  >> Robert and Herbert (the robot)<br>
...........................................................................<br>
                  Murray Altheim <murray18 at altheim dot com>   
                                     = =  ===<br>
                  <a href="http://www.altheim.com/murray/"
                    rel="noreferrer" target="_blank"
                    moz-do-not-send="true">http://www.altheim.com/murray/</a> 
                                                     ===  ===<br>
                                                                       
                                = =  ===<br>
                       In the evening<br>
                       The rice leaves in the garden<br>
                       Rustle in the autumn wind<br>
                       That blows through my reed hut.<br>
                              -- Minamoto no Tsunenobu<br>
                  <br>
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