DPRG
DPRG List  



DPRG: Bump sensing

Subject: DPRG: Bump sensing
From: Robert L. Jordan rljordan at airmail.net
Date: Thu Mar 18 19:15:50 CST 1999

George,
Often roboters use one bump switch and a wrap around "bumper" that flips
the switch when any part of a side hits something.

Also, two switches on a free floating "bumper" can tell you
left   =   sw-x
right  =   sw-y
center =   sw-x + sw-y

==,=============,====  <--  bumper bar
  |sw-x         |sw-y  <--  switches
|-------------------|
| _       []      _ |
|| |      c      | ||
||a|             |b||
| -       d       - |
|         []        |
|-------------------|

Do the same on all sides. Even use 4 switches, 1 per corner and "link"
the side bumpers. Use rubber bands to suspend the bumper so it "folates"

somewhat between ridgid mounts (screw heads etc.)

Regards
Robert




George Vastianos wrote:

> Hello dear friends in DPRG
>
> These days Im buiding my first roverbot
> and i need some help about the bump
> sensing.
>
> My bot's platform made by plexyglass :
>
> <------- 45cm ------>
>
> |-------------------|   ^
> | _       []      _ |   |
> || |      c      | ||   |
> ||a|             |b|| 35cm
> | -       d       - |   |
> |         []        |   |
> |-------------------|   v
>
> a and b are two hacked servos with
> wheels mounted on them...
> c and d are two caster wheels.
>
> By controling the direction (CW/CCW) and
> the state (ON/OFF) of each servo motor
> i can navigate my bot very easy. (I use
> only 4 bits)
>
> About the collision avoidance and
> detection i think to start with
> some whiskers....
>
> \ e    f/    \g    h/
> |\-----/------\----/|
> | _       []      _ |
> || |      c      | ||
> ||a|             |b||
> | -       d       - |
> |         []        |
> |/-----\------/----\|
>
> /i     j\    /k    l\
>
> I am thinking to use 8 whiskers because
> the platform is a little big (45cm x 35cm)
> and the whiskers are too short (7,5cm)
> (for whiskers I use some bump switches)
>
>      <---------7,5cm------->
>                          __
>      ___________________/  \
>     /
> /---|-------\
> |         o |--- nc
> | o         |--- no
> \-----------/
>       |_____ com
>
> In my mind i have some algorithms
> about the object avoidance but
> I think its better to hear and
> others' opinions about the problem...
>
> any comments???????
>
> thanks
>
> George Vastianos
>
> P.S. For the navigation I'm using
> two motors. Is this means that my
> bot has a 2-freedom degree navigation
> system or not?????

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


More information about the DPRG mailing list