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- PLEASE BE PATIENT -
YOUR COMMENTS ARE REQUESTED
Last updated 7/29/2001. Added missing Wilby drawings in DXF format. Introduced JPG format drawings for CADless drawing viewing. Also added Dasiy drawings and JPGs.
This page maintained by
dkdeckmann@aol.com
Click to see the LAB EQUIPMENT that I have FOR SALE.
(http://members.aol.com/dkdeckmann/lab/index.htm)
Wilby Walker is a Hexapod robotic development platform. Wilby Walker's mission is to facilitate my development of robotic devices and programming. Wilby Walker's primary purpose is to aid me in the development of:
A walking machine to evaluate the practicality of designing ind implementing a walking platform versus conventional wheeled platforms.
Evaluating the OOPic microcontroller for use in such projects versus other controllers such as Basic Stamp, PICs, Rabbits, 68HC11, BASICX, etc.
Evaluate remote vision and telemetry systems using CCD and similar cameras, ATV transmitters and video overlay circuits.
Evaluate sheet acrylic as a construction media.
Evaluate hobby type servos as a means of control and locomotion.
Evaluate various sersor devices such as Polaroid SONAR, infarad proximity detectors, bump switches, feelers, etc. as they may be employeed in such robotic devices.
Wilby Walker construction notes.
times.
Free counters provided by Honesty.com .
View 4 of WilbyWalker.
Acrylic seems to machine better with higher feed pressures and lower speeds. Too fast tool movement seems to result in meltdown. A table saw with a carbide blade seems to cut it nicely as does a Dremel Scroll Saw. Keep your blade sharp and your cut free of shavings or it will get hot and sticky. A Delta 1 inch belt / 5 inch disk sander does a fine job smoothing but tends to melt it a little. I speed control might be the answer. A Unimat lathe was used for most of the drilling operations.
Click to see view 1 of WilbyWalker.
The project is controlled by a standard OOPIC with several i/o pins left over. Each leg carries its own 4 AA cell battery for its two servos. This design lets half of the battery weight rest on the ground at all times raising its payload accordingly. The OOPIC is mounted in the hexapod's butt making it difficult to not name it after someone I know, instead it is named after one of my dogs, Wilber.
Click to visit the OOPIC web site to find out more about this controller.
Click to see view 2 of WilbyWalker.
The DB-25 connector on the top, not shown in the drawings, serves two purposes; fitted with a jumpered plug it serves as an emergency STOP by pulling the plug power is removed from all servos, and it provides seperate connection to each of the six batteries for charging. In its current form Wilby walks under the control of a gutted IBM/Apple joystick, looking at the two pots via 2 of the 4 OOPICs a/d converters. This a/d value is then scaled down and used to control the swing of each side when taking a step.
Click to see view 3 of WilbyWalker.
The two serial communication lines and the I2C bus along with several of the OOPIC's i/o lines are currently unused. Plans for the future include a sensory head for mounting SONAR hacked from an old Polaroid camera, b&w video camera - with infared sensitivity - a video overlay generator from Intuitive Circuits for telemetry and an ATV transmitter from PC Electronics, and whatever else it can carry.
Click to visit the Intuitive Circuits site to find out more about this video overlay generator.
Click to visit the PC Electronics site to find out more about this transmitter.
You may use the following DXF files if your CAD program supports DXF. Many do. If you can not or do not wish to use a CAD program you may view my drawings in JPG format using your browser by clicking on the JPG links.
Click to see view 5 of WilbyWalker.
Click to see view 6 of WilbyWalker.
Upper leg
Six of these are required, 3 left hand, 3 right hand. These were made from 1/4 inch thick sheet arcylic. Holes for leg links should be just big enough to pass #8 hardware without binding. Semicircular notch at bottom end as required to clear servo horn screw head. End drill bottom end to conform to your servo horn & thread for #4 sheetmetal or machine hardware End drill top to pass #4 machine hardware without binding for top pivot. Holes for wire ties 1/8 inch typical.
Click to view upleg.jpg - Upper leg drawing - Added 7/29/2001.
Click to download upleg.dxf - Upper leg drawing - Updated 7/22/2001, dimensions normalized.
Leg link for connecting upper leg to lower leg
Twenty-four of these are required. These were made from 1/8 x 1/2 inch bar aluminium. Holes should be just big enough to pass #8 hardware without binding. Make and keep in matched pairs to prevent binding. Assemble #8-32x1-1/4 screw, washer, link, washer, leg, washer, link, washer, lock nut. Over tightening lock nut results in unacceptable binding.
Click to view leglink.jpg - Connecting link for legs drawing. Added 7/29/2001.
Click to download leglink.dxf - Connecting link for legs drawing.
Lower leg
Six of these are required, 3 left hand, 3 right hand, Make them the same, just flop them over! These were made from 1-1/2" x 8" x 1/4" arcylic. Notch for servo need to conform to the requirements of your servo. Holes for servo mounting screws need to conform to your servo mounting requirements. Holes for leg links should be just big enough to pass #8 hardware without binding. Holes for battery ties 1/8 inch typical. Batteries and wires are secured with standard wire ties. Holes at corners of servo notch not required but included for ease of construction, 1/8 inch.
Click to view lowleg.jpg - Lower leg drawing - Added 7/29/2001.
Click to download lowleg.dxf - Lower leg drawing - Updated 7/22/2001, dimensions normalized.
Crank Link
Six of these required. These were made from 1/2" x 1/8" aluminium.
Click to view cranknk.jpg - Link for connecting legs to servo drawing. Added 7/29/2001.
Click to download cranknk.dxf - Link for connecting legs to servo drawing. Added 7/29/2001.
Upper body
One of these is required. This was made from 1/4 inch thick sheet arcylic. Drill top pivot holes to just pass #4 machine hardware. Assemble top pivots, 4-40x3/4 screw, washer, upper body, washer, nut, washer.
Click to view upbody.jpg - Upper body drawing - Added 7/29/2001.
Click to download upbody.dxf - Upper body drawing - Updated 7/29/2001.
Body spacer
Three of these are required. These were made from 1/2 inch thick sheet arcylic. End drill for #4 sheetmetal or machine threads.
Click to view bodyspac.jpg - Spacer between upper and lower body drawing. Addedd 7/29/2001.
Click to download bodyspac.dxf - Spacer between upper and lower body drawing. Addedd 7/29/2001.
Lower body
One of these is required and is the hardest part of the whole project. This was made from 4" x 14" x 1/4" thick sheet arcylic. Notch for servo need to conform to the requirements of your servo. Holes for servo mounting screws need to conform to your servo mounting requirements.
Click to view lowbody.jpg - lower body drawing in JPG format. Added 7/28/2001.
Click to download lowbody.dxf - Lower body drawing - Updated 7/22/2001, dimensions normalized.
BASIC Source for the OOPic here! No attempt has been made to optimize this for speed or size. Just quick and dirty to get results ASAP for platform evaluation. Not a complete "personality", Just a few routines to move the thing around. Several things can be done to make the code a little fancier including naming the legs using a for/next loop and giving them array names rather than easily decoded ones. Only 6 different outputs are really needed for this to work but some servos would have to look at the same OOPIC control lines. A nice touch would be a startup delay and setting the legs to a specific starting point. Might be nice to stop the legs from marching when no speed/direction is present. You name it. This is a starting point...
Click to view joywalk1
A modification for more inscect like movement was sent to me by Scott Savage. This makes for nice movement but It, of course, will need modification for steering, etc.
Click to view bugwalk1
FUTURE PROJECT PLANS
See if you can get it off of the drawing board before I do.
Here are a couple of drawings in DXF format for viewing or editing using your CAD program. Also a couple of drawings in JPG format for viewing directly from your browser. These are for one of my proposed project series using the same legs and control as Wilby Walker but featuring unique body style. You'll see why I named the project Daisy.
Click to see lower body drawing of Daisy 6 in JPG format. CAD not required!
You can guess what Daisy 8 might look like... Like Daisy 6 but 8 legs...
Click to download DXF drawing of Daisy 6 body part.
Click to download DXF drawing of Daisy 8 body part.
Click for my contact info, dkdeckmann@aol.com