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Robo Quad - Stage One
Powered Front Paws
History
As you may or may not know, I have been studying rolling walking quad hybrids.
 
 
After working on several proto-types and looking at the various design
challenges,
I have started a fully robotic version.
The first of these Quads was the
Rabbit Wrecker.
The Rabbit Wrecker is a cool little creation that has lot’s of articulation.
Although later designs would use different joint set up and placements.
The idea was to show use of the wheels at the feet.
Using wheels at the ends of legs on quads and multi-peds is nothing new.
I wanted to create a robot that could climb stairs using technology and
construction techniques developed when I built the
Jamocklaquat.
Adding wheels to the feet seemed like a good way to help push and pull the
robot up a stair case as well as navigate other obsticles. Plus wheels are
such an inherently man made design, I wanted to blend man’s technology with
nature’s ubiquitous multi-ped; the Quadra-ped.
I then started to create a mechanical chasis to explore cam driven shoulder
joints with the begining of the
Blue Quad. This worked
great, but was not
reliable when given a heavy load. Also the system needed to
be more robust
due to the high stress level the upper shoulder joints would
encounter.
The mechanical chasis was really cool, it even sported a pivoted spine that
channeled the drive shaft’s power through a center mounted U-joint.
Though with out enough power and controllability, I scrapped the idea and saved
it
for a more proper build, hopefully in the final version.
After I made the Blue Quad, I wanted to make a more sporty and fun version.
Something like the ultimate off road 4x4 vehicle of the future.
I imagined the Quadra-Mech as a rough riding machine built for fun.
The Quadra-Mech took
advantage of ball joints at the shoulders.
Allowing for good articulation and a
reliable system for this particular job.
It was around this time, that I
realized, the lower portion of a Quad’s legs
needed to twist in relation to the
upper shoulder. This movement is called
“splay” and is much the same as the
action and relation the hips and ankles
have in a bi-pedal mecha or humanoid
form.
Beacuse of the emense force and weight bearing load of this foward most
joint, the rotational plane needed to be reinforced by using a flange to
better distribute the weight and force so the joint wouldn’t pop out under
load.
I carried this lesson on to the next test proto-type;
the Red Quad
It was novel to add the NXT to the Red Quad to add some personality.
Though the motors are kind of large, they work well and provide for some
interesting programming possibilites.
I did stumble upon a new way to mount a worm driven z40 using some odd
stud less parts and a traditional triangle plate set up.
The next test was to make a Quad that was a little more streamlined and sleek
looking. The Green Quad
is definetly the sport version.
Not much more inovation was made with this model, aside from testing out new
ball jointed shoulder geometries. The Green Quad was also a replacement for a
much needed green model within my creations. Though it does feature the most
stable foot print, the double jointed spine really adds a new dynamic to the
way it stands.
Now comes the fun part!
The Robo Quad’s time has come. Enough with the models and proto-types.
Now it is time to build a fully robotic version!
This is Stage One of the process.
Goals:
- Use RC racer motors to power the drive wheels.
- Use a motorized turntable for the ankle steering.
- Black Technic and plates.
- Sturdy and reliable.
The Robo Quad’s front paws are very strong. I used RC racer motors to power
the wheels. I added a powerful gear train to the set up. When the RC motor
is running and when a load is applied to the wheel, it is very difficult to
stop by hand.
  
Next: Stage Two
Goals:
- Create reinforced motorized flange for ankle steering.
- Determine best configuration for the elbow joints; turntable or beam to z40.
- Create rear paws.
- Prepare rear lower leg section.
Later and advanced stage notes:
The Robo Quad will feature RC controllers mounted in the body.
I also picked up two Batmobiles so I could have really cool eye canopies.
I will try to add a Vision Command Sensor Camera in the head.
Upper shoulders will be turntable driven.
Still speculating on the upper most shoulder splay functions and placement.
Eye lights will be from HiTechnic; UV LED’s.
RC Racer and RCX controllers.
The Robo Quad challenges include driving forward, turning, walking, and
climbing.
If you are interested in trying out your own design, now is the time to join
me during this early process of documentation. While difficult to provide
exact building instructions, this series of design notes can aid in helping
to make your own. Go for it!
Stay tuned for Stage Two.
Robo Quad - Stage One
Powered Front Paws
Eric Sophie
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Message has 2 Replies:
 | | Re: Robo Quad - Stage One
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| Hi Eric, this is a really interesting project. I'll promise to follow your progress, even though I can't join. This project will push Mecha building to a new stage! Best wishes (URL) Marco> (18 years ago, 4-Mar-07, to lugnet.robotics, lugnet.technic, FTX)
| | | Re: Robo Quad - Stage One
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| (...) Slight snippage has occurred ;o) Eric, The depth of thinking and your skill at building these Robo Quads is wonderful. I will follow this project, too. Since I'm a limited technic person, and am just getting exposed to NXT, I doubt I could (...) (18 years ago, 6-Mar-07, to lugnet.robotics, lugnet.technic, FTX)
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