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Building a Robo-Magellan bot

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  • Bob Cook
    Hey everyone, The Robothon event is still seven months away and I ve been wanting to build an entry for the Robo-Magellan event ever since the first year it
    Message 1 of 6 , Feb 17, 2013
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      Hey everyone,

      The Robothon event is still seven months away and I've been wanting to build an entry for the Robo-Magellan event ever since the first year it was run. I figure there must be others out there with the same desire and maybe already making great progress.

      There was a great article in the recent Robot magazine issue about Chibots' event that made for interesting reading.

      Here are some thoughts I've had about how to make an effective robot:

      - Start with an RC truck, preserving as much of the built-in hardware and electronics as possible, to save time building up the chassis
      - Expect to drive over long grass as well as hard surfaces, so bigger is better
      - Will need to avoid obstacles like trees and people, so some sort of ultrasonic rangefinders are will be helpful
      - Physical bump sensors are probably nice to have but don't seem strictly required
      - GPS won't be accurate enough as the only navigational aid, but could provide useful information
      - ArduPilot might be a useful platform to build upon (although I have yet to look at it, might be too specific for planes)
      - Finding the cone seems to be a challenge best solved visually e.g. a web cam + OpenCV
      - Some sort of remote "kill switch" is going to be required
      - Testing, testing, testing and more testing

      I've seen the very impressive works of David Anderson (jBot) and Mark Curry (Intrepid and Nomad) and others as well.

      I'm really curious to hear what other people are doing e.g. what do you think of my approach?

      Are you are building something for Robo-Magellan?

      - Bob
    • K Maxon
        Hi Bob,   I ve  got  0.02$ worth of input to add.   That is until the Gov t stops making pennies and nickles next year.   I was lucky enough to attend
      Message 2 of 6 , Feb 17, 2013
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        Hi Bob,
         
        I've  got  0.02$ worth of input to add.   That is until the Gov't stops making pennies and nickles next year.
         
        I was lucky enough to attend a ChiBots robo-magellan event here a few years back.  They have some really great / active members in the group. 
         
        On the coment about bigger  is better.   In general, this is true up  to a point in respect to rough terain navigation, however, bigger is better is at odds with the hard weight target for the event, so I would encourage you to keep that in mind when selecting components & materials.  Bigger means higher torques for the larger moments involved.  Higher torques means stronger gears and shafts (often moving from plastics into aluminum or possibly steel.)   David and others have written on this subject even with their 20~30lb class  robots, tearing up components in the gear train.   As you move to material selections that can handle the higher torque often (not always) you are going to move towards materials that  weight significantly more.
         
        My robot Protobot has 10-in tires and can drive into a freshly plowed wheat field (massive furrows & clods & all) without to much problem, where a smaller RC platform would be "challenged".  This goes a long way to support the bigger is better statement, however...
         
        While in Chicago at the ChiBots event I watched a very small very light weigth robot not  much  bigger than my feet complete about  1/2 of the course.  Mechanically, this robot was largely built from lego and  plastic pieces.  It  performed quite well and although it wasn't extremely easy going on the grass, it managed to keep making progress.  The struggle with this robot was not mechanical, but rather, it was just the amount of time the builder had to finish off the software.  This of  course flys directly in the  face of bigger is better.
         
        Just some food for thought....  If you can easily  pick it up and lug it back to the  starting line over and over, you'll get  more time in for your last bullet item, testing, testing, testing.   If you can put it in your briefcase and pull it out at lunch time with your laptop or  even on your desk, you are again increasing the likely hood for testing which seems to be one of those leading issues that keeps  people from finishing.  (Just not enough time to  finish coding and testing.) 
         
        -Kenneth

        From: Bob Cook <bob@...>
        To: "SeattleRobotics@yahoogroups.com" <SeattleRobotics@yahoogroups.com>
        Sent: Sunday, February 17, 2013 9:50 AM
        Subject: [SeattleRobotics] Building a Robo-Magellan bot

        Hey everyone,

        The Robothon event is still seven months away and I've been wanting to build an entry for the Robo-Magellan event ever since the first year it was run. I figure there must be others out there with the same desire and maybe already making great progress.

        There was a great article in the recent Robot magazine issue about Chibots' event that made for interesting reading.

        Here are some thoughts I've had about how to make an effective robot:

        - Start with an RC truck, preserving as much of the built-in hardware and electronics as possible, to save time building up the chassis
        - Expect to drive over long grass as well as hard surfaces, so bigger is better
        - Will need to avoid obstacles like trees and people, so some sort of ultrasonic rangefinders are will be helpful
        - Physical bump sensors are probably nice to have but don't seem strictly required
        - GPS won't be accurate enough as the only navigational aid, but could provide useful information
        - ArduPilot might be a useful platform to build upon (although I have yet to look at it, might be too specific for planes)
        - Finding the cone seems to be a challenge best solved visually e.g. a web cam + OpenCV
        - Some sort of remote "kill switch" is going to be required
        - Testing, testing, testing and more testing

        I've seen the very impressive works of David Anderson (jBot) and Mark Curry (Intrepid and Nomad) and others as well.

        I'm really curious to hear what other people are doing e.g. what do you think of my approach?

        Are you are building something for Robo-Magellan?

        - Bob



        ------------------------------------

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      • Bob Cook
        Hi Kenneth, Thank you for your thoughts. I ve always been in awe of your projects, absolutely beautiful construction. Glad to hear Protobot is coming along
        Message 3 of 6 , Feb 18, 2013
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          Hi Kenneth,

          Thank you for your thoughts. I've always been in awe of your projects, absolutely beautiful construction. Glad to hear Protobot is coming along nicely, driving through a wheat field is more ambitious than I'm looking to do, but I take your point about size vs. weight. I think I'll end up with an RC truck as the chassis, it is likely good enough for the terrain at Seattle Center and should give me plenty of opportunity to focus on the software, sensors, and testing.

          I wonder if you are describing "Green Monster" made from Lego? I saw that robot in Seattle once, and it sounds like it was a decent contender at the Chibots event this past year. That is reassuring, because as far as the mechanics and construction go, its very accessible to everyone. There is a nice description and pictures in that Robot Magazine article.

          As for testing, I wonder if its worthwhile to build a simulator in software, to make iterative design-code-test-evaluate cycles easier. Not sure how many people have built both simulators and the hardware to match. Does anyone have experience to share?

          Oh and I forgot to mention in the last email: the presentation by David Anderson re: behavior-based controller design gave me ideas for my own controller. For anyone who doesn't know about this, here is the YouTube link: http://www.youtube.com/watch?v=8CXReb7f0Eo

          Thanks,
          Bob


          On 2013-02-17, at 3:10 PM, K Maxon <k_maxon23@...> wrote:



           
          Hi Bob,
           
          I've  got  0.02$ worth of input to add.   That is until the Gov't stops making pennies and nickles next year.
           
          I was lucky enough to attend a ChiBots robo-magellan event here a few years back.  They have some really great / active members in the group. 
           
          On the coment about bigger  is better.   In general, this is true up  to a point in respect to rough terain navigation, however, bigger is better is at odds with the hard weight target for the event, so I would encourage you to keep that in mind when selecting components & materials.  Bigger means higher torques for the larger moments involved.  Higher torques means stronger gears and shafts (often moving from plastics into aluminum or possibly steel.)   David and others have written on this subject even with their 20~30lb class  robots, tearing up components in the gear train.   As you move to material selections that can handle the higher torque often (not always) you are going to move towards materials that  weight significantly more.
           
          My robot Protobot has 10-in tires and can drive into a freshly plowed wheat field (massive furrows & clods & all) without to much problem, where a smaller RC platform would be "challenged".  This goes a long way to support the bigger is better statement, however...
           
          While in Chicago at the ChiBots event I watched a very small very light weigth robot not  much  bigger than my feet complete about  1/2 of the course.  Mechanically, this robot was largely built from lego and  plastic pieces.  It  performed quite well and although it wasn't extremely easy going on the grass, it managed to keep making progress.  The struggle with this robot was not mechanical, but rather, it was just the amount of time the builder had to finish off the software.  This of  course flys directly in the  face of bigger is better.
           
          Just some food for thought....  If you can easily  pick it up and lug it back to the  starting line over and over, you'll get  more time in for your last bullet item, testing, testing, testing.   If you can put it in your briefcase and pull it out at lunch time with your laptop or  even on your desk, you are again increasing the likely hood for testing which seems to be one of those leading issues that keeps  people from finishing.  (Just not enough time to  finish coding and testing.) 
           
          -Kenneth

          From: Bob Cook <bob@...>
          To: "SeattleRobotics@yahoogroups.com" <SeattleRobotics@yahoogroups.com> 
          Sent: Sunday, February 17, 2013 9:50 AM
          Subject: [SeattleRobotics] Building a Robo-Magellan bot

          Hey everyone,

          The Robothon event is still seven months away and I've been wanting to build an entry for the Robo-Magellan event ever since the first year it was run. I figure there must be others out there with the same desire and maybe already making great progress.

          There was a great article in the recent Robot magazine issue about Chibots' event that made for interesting reading.

          Here are some thoughts I've had about how to make an effective robot:

          - Start with an RC truck, preserving as much of the built-in hardware and electronics as possible, to save time building up the chassis
          - Expect to drive over long grass as well as hard surfaces, so bigger is better
          - Will need to avoid obstacles like trees and people, so some sort of ultrasonic rangefinders are will be helpful
          - Physical bump sensors are probably nice to have but don't seem strictly required
          - GPS won't be accurate enough as the only navigational aid, but could provide useful information
          - ArduPilot might be a useful platform to build upon (although I have yet to look at it, might be too specific for planes)
          - Finding the cone seems to be a challenge best solved visually e.g. a web cam + OpenCV
          - Some sort of remote "kill switch" is going to be required
          - Testing, testing, testing and more testing

          I've seen the very impressive works of David Anderson (jBot) and Mark Curry (Intrepid and Nomad) and others as well.

          I'm really curious to hear what other people are doing e.g. what do you think of my approach?

          Are you are building something for Robo-Magellan?

          - Bob



          ------------------------------------

          Visit the SRS Website at http://www.seattlerobotics.orgYahoo! Groups Links

          <*> To visit your group on the web, go to:
              http://groups.yahoo.com/group/SeattleRobotics/

          <*> Your email settings:
              Individual Email | Traditional

          <*> To change settings online go to:
              http://groups.yahoo.com/group/SeattleRobotics/join
              (Yahoo! ID required)

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        • Steve Hassenplug
          Bob, The biggest mistake I see people make, is that they try to build the perfect robot on their first attempt. If you just start with a cheap 4wd RC
          Message 4 of 6 , Feb 18, 2013
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            Bob,

            The biggest mistake I see people make, is that they try to build the perfect robot on their first attempt.

            If you just start with a cheap 4wd RC car/truck, you can design a system that can simply control two servos (one for steering, another for the speed controller).  That will allow you to have a moving robot, without much trouble.  Down the road, you can upgrade the chassis, if you wish.

            For sensors, I would recommend (in order)
            GPS
            Compass
            Camera (cone detection)
            Object sensor(s) (ultra-sonic)
            Wheel Encoder
            Touch/bump sensor(s)

            The controller is really wide-open.  If you Google these types of robots, the main thing you'll find is that they all use different controllers.  My current favorite controller is my cell phone, and a connected IOIO board for I/O.

            In '07 I brought a robot to the Robomagellan in Seattle.  It was about 1 month old, and didn't do very well.  I came home, and convinced Chibots to run the event.  In '08 Kennith was there as my robot completed the first Chibots' course.

            This year, that same robot got third place in the event you read about, while my newest creation (still only a few months old) got a respectable fourth place.

            My advice: Start now.  Get something rolling.  Then, you have more time to figure out "why is it doing that?"

            Good luck
            Steve




            On Sun, Feb 17, 2013 at 12:50 PM, Bob Cook <bob@...> wrote:
             

            Hey everyone,

            The Robothon event is still seven months away and I've been wanting to build an entry for the Robo-Magellan event ever since the first year it was run. I figure there must be others out there with the same desire and maybe already making great progress.

            There was a great article in the recent Robot magazine issue about Chibots' event that made for interesting reading.

            Here are some thoughts I've had about how to make an effective robot:

            - Start with an RC truck, preserving as much of the built-in hardware and electronics as possible, to save time building up the chassis
            - Expect to drive over long grass as well as hard surfaces, so bigger is better
            - Will need to avoid obstacles like trees and people, so some sort of ultrasonic rangefinders are will be helpful
            - Physical bump sensors are probably nice to have but don't seem strictly required
            - GPS won't be accurate enough as the only navigational aid, but could provide useful information
            - ArduPilot might be a useful platform to build upon (although I have yet to look at it, might be too specific for planes)
            - Finding the cone seems to be a challenge best solved visually e.g. a web cam + OpenCV
            - Some sort of remote "kill switch" is going to be required
            - Testing, testing, testing and more testing

            I've seen the very impressive works of David Anderson (jBot) and Mark Curry (Intrepid and Nomad) and others as well.

            I'm really curious to hear what other people are doing e.g. what do you think of my approach?

            Are you are building something for Robo-Magellan?

            - Bob


          • Tony Mactutis
            From what I saw last year, all you need to be in the running is a mobile platform that can drive on grass and sidewalks and follow GPS waypoints. The bar may
            Message 5 of 6 , Feb 18, 2013
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              From what I saw last year, all you need to be in the running is a mobile platform that can drive on grass and sidewalks and follow GPS waypoints. 

              The bar may have been lowered a bit from previous years but I think that will be a good thing, if it encourages new people to try.

              Tony

              On 2/18/2013 6:56 AM, Steve Hassenplug wrote:
               
              Bob,

              The biggest mistake I see people make, is that they try to build the perfect robot on their first attempt.

              If you just start with a cheap 4wd RC car/truck, you can design a system that can simply control two servos (one for steering, another for the speed controller).  That will allow you to have a moving robot, without much trouble.  Down the road, you can upgrade the chassis, if you wish.

              For sensors, I would recommend (in order)
              GPS
              Compass
              Camera (cone detection)
              Object sensor(s) (ultra-sonic)
              Wheel Encoder
              Touch/bump sensor(s)

              The controller is really wide-open.  If you Google these types of robots, the main thing you'll find is that they all use different controllers.  My current favorite controller is my cell phone, and a connected IOIO board for I/O.

              In '07 I brought a robot to the Robomagellan in Seattle.  It was about 1 month old, and didn't do very well.  I came home, and convinced Chibots to run the event.  In '08 Kennith was there as my robot completed the first Chibots' course.

              This year, that same robot got third place in the event you read about, while my newest creation (still only a few months old) got a respectable fourth place.

              My advice: Start now.  Get something rolling.  Then, you have more time to figure out "why is it doing that?"

              Good luck
              Steve




              On Sun, Feb 17, 2013 at 12:50 PM, Bob Cook <bob@...> wrote:
               

              Hey everyone,

              The Robothon event is still seven months away and I've been wanting to build an entry for the Robo-Magellan event ever since the first year it was run. I figure there must be others out there with the same desire and maybe already making great progress.

              There was a great article in the recent Robot magazine issue about Chibots' event that made for interesting reading.

              Here are some thoughts I've had about how to make an effective robot:

              - Start with an RC truck, preserving as much of the built-in hardware and electronics as possible, to save time building up the chassis
              - Expect to drive over long grass as well as hard surfaces, so bigger is better
              - Will need to avoid obstacles like trees and people, so some sort of ultrasonic rangefinders are will be helpful
              - Physical bump sensors are probably nice to have but don't seem strictly required
              - GPS won't be accurate enough as the only navigational aid, but could provide useful information
              - ArduPilot might be a useful platform to build upon (although I have yet to look at it, might be too specific for planes)
              - Finding the cone seems to be a challenge best solved visually e.g. a web cam + OpenCV
              - Some sort of remote "kill switch" is going to be required
              - Testing, testing, testing and more testing

              I've seen the very impressive works of David Anderson (jBot) and Mark Curry (Intrepid and Nomad) and others as well.

              I'm really curious to hear what other people are doing e.g. what do you think of my approach?

              Are you are building something for Robo-Magellan?

              - Bob



            • Carol
              I don t have any creds yet at Robo-Magellan but have been building one for this year s competition. I am using the 4 wheel version of the Minds-i vehicle. It
              Message 6 of 6 , Feb 19, 2013
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                I don't have any creds yet at Robo-Magellan but have been building one for this year's competition. I am using the 4 wheel version of the Minds-i vehicle. It has 4 wheel drive and 4 wheel steering so there is plenty of low end torque and the turning radius is tighter than you can get with an RC truck. The microcontroller is an Arduino mega 2560 with a Mega shield. I have five Ping sonar sensors on the front and one on the back. There is of course a GPS sensor and a compass. I also added a Memsic tiltometer to keep the vehicle from going into a steep ditch or too steep a hill. Instead of a camera system that requires a lot of weight and fancy programming I am using a color sensor that simply reports wether the object is orange or not. If it is orange, then there is a bumper on the front of the vehicle that will gently touch the cone without knocking it over or moving it. The robot now also knows to go to the next GPS site. It is a more simplistic approach than others are taking but the kiss principle has always worked well for me. Of course there are a lot of complicated behaviours I have to program into the system but it would take a lot of space here to give you a complete idea of what I am doing.

                --- In SeattleRobotics@yahoogroups.com, Tony Mactutis <tony@...> wrote:
                >
                > From what I saw last year, all you need to be in the running is a
                > mobile platform that can drive on grass and sidewalks and follow GPS
                > waypoints.
                >
                > The bar may have been lowered a bit from previous years but I think that
                > will be a good thing, if it encourages new people to try.
                >
                > Tony
                >
                > On 2/18/2013 6:56 AM, Steve Hassenplug wrote:
                > > Bob,
                > >
                > > The biggest mistake I see people make, is that they try to build the
                > > perfect robot on their first attempt.
                > >
                > > If you just start with a cheap 4wd RC car/truck, you can design a
                > > system that can simply control two servos (one for steering, another
                > > for the speed controller). That will allow you to have a moving
                > > robot, without much trouble. Down the road, you can upgrade the
                > > chassis, if you wish.
                > >
                > > For sensors, I would recommend (in order)
                > > GPS
                > > Compass
                > > Camera (cone detection)
                > > Object sensor(s) (ultra-sonic)
                > > Wheel Encoder
                > > Touch/bump sensor(s)
                > >
                > > The controller is really wide-open. If you Google these types of
                > > robots, the main thing you'll find is that they all use /different/
                > > controllers. My current favorite controller is my cell phone, and a
                > > connected IOIO board for I/O.
                > >
                > > In '07 I brought a robot to the Robomagellan in Seattle. It was about
                > > 1 month old, and didn't do very well. I came home, and convinced
                > > Chibots to run the event. In '08 Kennith was there as my robot
                > > completed the first Chibots' course.
                > >
                > > This year, that same robot got third place in the event you read
                > > about, while my newest creation (still only a few months old) got a
                > > respectable fourth place.
                > >
                > > My advice: Start now. Get something rolling. Then, you have more
                > > time to figure out "why is it doing that?"
                > >
                > > Good luck
                > > Steve
                > >
                > >
                > >
                > >
                > > On Sun, Feb 17, 2013 at 12:50 PM, Bob Cook <bob@...
                > > <mailto:bob@...>> wrote:
                > >
                > > Hey everyone,
                > >
                > > The Robothon event is still seven months away and I've been
                > > wanting to build an entry for the Robo-Magellan event ever since
                > > the first year it was run. I figure there must be others out there
                > > with the same desire and maybe already making great progress.
                > >
                > > There was a great article in the recent Robot magazine issue about
                > > Chibots' event that made for interesting reading.
                > >
                > > Here are some thoughts I've had about how to make an effective robot:
                > >
                > > - Start with an RC truck, preserving as much of the built-in
                > > hardware and electronics as possible, to save time building up the
                > > chassis
                > > - Expect to drive over long grass as well as hard surfaces, so
                > > bigger is better
                > > - Will need to avoid obstacles like trees and people, so some sort
                > > of ultrasonic rangefinders are will be helpful
                > > - Physical bump sensors are probably nice to have but don't seem
                > > strictly required
                > > - GPS won't be accurate enough as the only navigational aid, but
                > > could provide useful information
                > > - ArduPilot might be a useful platform to build upon (although I
                > > have yet to look at it, might be too specific for planes)
                > > - Finding the cone seems to be a challenge best solved visually
                > > e.g. a web cam + OpenCV
                > > - Some sort of remote "kill switch" is going to be required
                > > - Testing, testing, testing and more testing
                > >
                > > I've seen the very impressive works of David Anderson (jBot) and
                > > Mark Curry (Intrepid and Nomad) and others as well.
                > >
                > > I'm really curious to hear what other people are doing e.g. what
                > > do you think of my approach?
                > >
                > > Are you are building something for Robo-Magellan?
                > >
                > > - Bob
                > >
                > >
                > >
                >
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