Details and Diagrams of MicroFork

As far as I can tell there are only a few major modules to MiroFork. Here they are:

• Drive Module - Applies force to the ground so MicroFork can move.
• Tool Fixture - securely attaches a tool to MicroFork and moves that tool relative to MicroFork.
• Power Module - Feeds other components with energy. This is a PowerCube.
• Control Module - Allows the behavior of other components to be controlled by the driver.
• Tool Module - One of many possible machines that attach to MicroFork (eg, snowplow, tiller, etc.)
• Passenger Module (optional) - Allows the Driver to ride on MicroFork.

In the spirit of hypermodularity, each of these modules should define interfaces such that they can easily be swapped out. This modularity is somewhat expensive. It requires additional materials and manufacturing as compared to an integrated tool. For long lived, versatile tools it's worth it.

Here are my vague ideas on these components and interfaces. I've already posted a little on the drive unit. I now consider those thoughts largely irrelevant. The drive unit can be implemented in lots of ways depending on the requirements. I'm reluctant to make MicroFork a skid steer because I want it to be useful on a suburban lawn (so no skid marks). I'm leaning toward a lawn tractor type design-- 4 wheels, two steerable, two powered by a differential transmission which is in turn powered by a hydraulic motor. This is complex, but would be manageable with salvaged parts. This isn't a good long term OSE solution but would work for me personally in the short run.

The Tool Fixture is the core of MicroFork. All other components attach to it. I'm like my forklift style manipulator because I imagine it to be simple to build and sufficiently flexible for MicroFork type work.

Time for the pictures! To the left is a the forklift based tool fixture. The green plate would support multiple attachment schemes. The two important ones are Bobcat quick disconnect, and 3 point hitch (like the one on my Dad's John Deer tractor-- probably class 2). A big feature of this design is ease of dis-assembly. The pins holding together the pivots can be removed to collapse the whole thing. Having multiple brown members of different lengths, allows the angle of the green plate relative to the ground to be changed. 

Next is the interface design between the Drive Module and the Tool Fixture. This is a simple 'drop and pin' arrangement. It doesn't allow for any movement, but is very general and should be (I'm guessing here) very strong. So long as the fixture and the drive module have correctly spaced joiners, it won't matter how they do their job (tracks, or skid, or articulated steering).

I still don't know how the other modules fit in. There may be problems with balance, strength, and alignment. I don't even know how a real forklift operates (I'm hoping to take a long look at one sometime soon.)

Ideally, if the interfaces were well defined/designed the different components of MicroFork could be implemented in parallel-- good job team WikiSpeed.

I was contacted by Graham who will be making a MicroFork this summer. I'm hoping to be able to help with the design if not the construction.

Alternative MicroTrac Design-- MicroFork

I've spent the last week between jobs and it has done wonders for my creativity-- I've got a lot more brain energy to devote to my flights of fancy. As such, I've got what I consider to be some major improvements to my MicroTrac design. I'm calling my proposal MicroFork. My next couple posts will be about it.

I spent a lot of time thinking about how to put arms onto MicroTrac so that it could lift an earth pulverizer up to the height of a CEB Press hopper. I've recently realized that this probably isn't a great requirement. First off, it's a pretty specialized task. LifeTrac seens like the right tool for that anyway. Besides that, it's quite different from other kinds of requirements that I can see MicroTrac being useful for. Goals like snow blowing/plowing, lawn mowing, tilling, posthole digging and the like are all done at relatively low heights

So instead, why not take inspiration from a different lifting requirement that MicroTrac should be able to handle. It should be able to load a pallet into a truck like a fork lift would. This has a much lower elevation requirement than loading a CEB, but is a general kind of utility MicroTrac should provide. I propose that this is the most height intensive requirement currently on the docket. So, why not take inspiration from the forklift which does the job very well. What would we end up with then? We'd get MicroFork.

(I'll post more thoughts soon.)

Where have you been? Why haven't you been posting?

My progress has been glacial lately. I have some pretty good reasons though...

1) My wife is Pregnant! We're expecting a new family member in late September.
2) Our family is primarily located in Michigan so we will be moving early June.
3) I just finalized the adoption of my son Frankie!
4) I've found a new job. I'll be working for Rolled Alloys. The job search was time consuming.

So, I'm not expecting to make much progress in the next few months. I will write occasionally with thoughts and other occurrences.

Interviewed by the Associated Press!

I got a call yesterday by a reporter for the Associated Press. She was doing investigation for an article that she might write about OSE. She asked a bunch of interesting questions and I enjoyed the conversation. I'm hoping the article gets written. I'll certainly link to it if it does.

Good at building. Bad at Posting.

It's been hectic. I've got a lot going on personally, so it's been hard to keep the posts flowing. However, progress is happening! I'm assembling my power cube! There are parts that still need to be ordered and assembled, but things are beginning to look up.

The Cube

I've assembled the Cube (above). It is the frame that holds all the components in place. After welding the corners together, my professor said that it could handle being dropped from an airplane.

The Reservoir

The hydraulic reservoir is air tight and ready to rock (above). I had to fix leaks twice during the leak tests. My PVC plugs held up to high pressures (60 PSI or more) without a problem-- still be careful if you're doing this yourself.

Reservoir in Cube

Tacking the Reservoir

I mounted the reservoir into the cube. It fit nicely so I tacked it in place. With it secured, I was ready to start positioning the engine mounting plate.

At least I thought I was ready. I had already assembled the engine mounting plate and its supports. The plate with the hole will receive the engine-- the engine shaft goes through the hole. The other plate is a vertical support which holds the plate up.

When placed into the cube I saw the image below. Can you tell what is wrong?

It turns out that the instructions were out of date. The holes they described placed the engine too close to the tank outlet. The intake hose that connects the hose to the pump can't make that sharp a bend. So I had to drill a new hole and move the engine mount away from the tank outlet.

Here is the plate after it has been moved and tacked. Can you tell what it wrong? The horizontal plate is no where near level. I didn't think it would be a problem but, the engine wouldn't fit right with this sag. I cut my tack welds and used a level to get everything square. Below you can see the scoring from the grinder and the new location of the support.

This made the engine fit nicely. You can see in the next image the thin slice of light coming between the engine and the tank. When the plate wasn't level, this clearance was taken up and the engine was resting on the reservoir.

So things are starting to look real. I'm very happy with my progress, though there is still a long way to go. My next post will include a really great trick for locating the holes that the engine bolts will go through.

Thinking about MicroTrac

As an American, I am required to want a big tractor. I do in fact want a big tractor. What do I need though? Can I get by with less? Enter MicroTrac (Top Right) a small version of LifeTrac (Bottom Right).

MicroTrac is in the early phases of the development process. It's also a better size for my near future needs. So I've been thinking about making a MicroTrac when my PowerCube is complete. I've been thinking a bit about high level design for such a tractor. My thoughts are below.

Things it should be able to do:

• Take interchangeable Attachments:
• Snowblower, Lawnmower, Snowplow, String Trimmer, Mini Forklift, Tiller, others?
• Powered steering.
• Optional ride behind or ride in front (depending on whether attachment is pulled or pushed).
• Low center of gravity. Reasonable stability & Balance.

To achieve this, I'm thinking of something like the diagram below.

Simple Concept for MicroTrac

It's primitive, but reasonably to scale. The cube in the middle is a Power Cube. It would rest securely in a frame. That fram would have two LifeTrac quick connect wheels attached near the midpoint. This keeps the center of mass low (but should still allow for maneuverability).

On the top are hydraulic valve controls which would control the wheels and the attachment. They would be movable so they could be at the front of the cube or the back. This allows the driver to push the attachment (snow plow) or pull the attachment (tiller).

The protrusion between the wheels is the attachment point. The would need to allow either a rigid or swiveling connection to a tool. To allow for loader type attachments (fork lift, bucket) there needs to be a more complex mounting mechanism available-- perhaps uprights at the back of the power cube that arms could attach to.

Finally, the drive could walk behind the tractor, attach a platform to stand on, or attach a seat of some sort.

My current reservations about this design:

• Geometry - Will everything fit? It should be possible but might be tight.
• Balance - There isn't a lot of weight in the back to keep MiniTrac from tipping forward. This is a big problem with lifting devices like a bucket, soil pulverizer, and forklift. Would a wheelie bar in the front help with those? Perhaps a caster in the back to keep from tipping backwards?
• Maneuverability - How agile will it be? What sort of grade could it climb?
• Ease of Control - The PowerCube is pretty powerful, how jerky will starting and stopping be? This can probably be mediated through clever hydraulics.
• Ease of implement attachment - The attachment mechanism needs to be strong and easy to work. Perhaps us the same align + cam mechanism that the wheel modules use?

I'd love to hear feedback in the comments below. How can this design be improved? Any suggestions on attachment mechanisms? etc. etc. etc.

Kicking Butt in the Shop

It feels like I've finally turned a corner in making my Power Cube. Things are going more quickly as I hit my stride. With so much progress, I'm going to change my format a little. I've been posting about each day in the shop. With the progress that I've been making that won't be coherent-- I'm doing too many different things to describe them well in a single post.

So, here is a laundry list from the last two weeks. I'll write followup posts with details on each process.

I used the CnC Plasma Torch to cut out the pump plate and engine mounting hole. I used a drill press to attach the engine mounting plate to the angle iron that it will be bolted to. I leak tested the Hydraulic Reservoir at 80 psi! And now for a fun picture:

Steel Pacman eating a green dot =)