Jun 092009

I made one of the first steps to turning a project from an idea to a reality this morning; making the first financial contribution to the project. While many times I have ideas for things I would like to do, I am careful about only investing in projects which I am GOING to do.  That milestone of my CNC router project happened when I purchased bearings for the machine.

I have been mulling over ideas on how to design this cnc. Mainly I have found 3 design plan sets which seem common online yet none of them meet my needs. Since I am incredibly picky about this sort of thing I figure the best thing to do is to take bits and pieces from different places and make something which is uniquely mine.

Joe’s CNC ( http://www.joescnc.com ) – He has 2 different designs. The first one was made in 2006 and is one of the standards that you see people on cnc forums talking about. His plans are free and it seems like a solid unit. The issue I have with it is that it is a full wrap carriage; meaning that the gantry travels under the work surface. This is bad for a number of reasons but mainly I got a super table to mount this on, namely the new Biesemeyer Extension table for the unisaw ( I wonder how I got that ) and that would prevent this design from going forward.  The second design from Joe is much better but I refuse to pay 100 bucks just for the plans for something I can design myself, I am not really into just building

The next set of plans is the JGRO Plans Like Joe’s plans it offers simple construction methods with MDF and some of the same features. If I was a betting man (which I am) i would say that one of these 2 sets of plans inspired the other. Full plans are available for this one for free, but I really dislike the way that he does linear motion. There is no way I can tell to hold reasonable accuracy with out really spending time tweaking the unit after assembly, something that I know is likely no matter which way I go.

The last type is from the site www.buildyourcnc.com  he has 2 different designs and the one I am going to make  most closely resembles his new machine the black toe while I don’t understand the name I really like the way his linear guides are done.

So the project starts, I purchased these v-bearings for a cheap price of 2.50 each and as I continue to spec my machine I will buy the parts which will help me create more cool projects in the future.

Jun 042009

As I mentioned one of my projects this summer is to convert an electric lawnmower to a robot.  Not only does this project appeal to me because of my laziness and not wanting to mow my own lawn but it allows for the creation of a platform which I can use for future developments.  I started to dig into this project a bit over the past week and now have 2 different directions which I am considering.

1)  A simple mechanical drive where I power the rear wheels and have casters on the front. This use of differential steering will be sufficient for my needs, but it doesn’t have that flare which makes a project stand out. On the other hand doing something simple (KISS FTW) may take the time required to finish the project more achievable.

2) My next thought is a mechanically more sophisticated system of using mecanum wheels on the robot.  Mecanum wheels are ones that allow for holonomic movement(movement in any direction) You can read more about them here http://en.wikipedia.org/wiki/Mecanum_wheel   One of issues with mecanum wheels is that they need to ensure contact with the ground at all time to work, which is why they are traditionally used in systems which roll on flat floors such as forktrucks. In the uneven ground of a yard or offroad the robot would require a suspension system, which is where the complexity begins.  Normally suspensions are straight forward because their only requirement is to keep traction and keeping close to the ground is not a factor like it is when mowing the lawn.  In the research I have done so far I have yet to find any off-road mecanum robots, in fact the closest I found is a concept for a mars surface vehicle. If I do go this route I plan on using the mecanum wheels from Andymark, as they offer 6inch8inch, and 10inch options with different modular hubs, which will make the challenge the implementation of the system not re-inventing the wheel.

This is the first paint style sketch of what I am thinking about if I decide to go down the mecanum path. Obviously the largest challenge is to keep the blade at a constant height so that I still have a good cut quality in addition to a autonomous robot cutting it.


May 182009

So I have reciently been complaining about not having stuff to do, yet I have a garage full of tools and a list of projects a mile long. I think it is time to be proactive and get some stuff done. So I have dubbed this the “summer of projects”

Here are a beginning list of things I AM going to work on.

  • Coaxial Swerve drive – my team wants to build one and convert the robot for IRI. I am waiting for the kids to start being proactive about this;as I am going to guide them, not design it for them.
  • Robotic lawn mower – Last year my boss gave me a black & decker electric lawn mower. Cutting my lawn is up there as a thing I don’t want to do so it makes sense. I will design and build a chassis for it and start by converting it to RC then add sensors and other goodness as time goes on.
  • CNC router – I have been interested in CNC for some time now and no matter how many times I have had things made for me I still don’t have much experience with it myself. So the net is filled with plans and ideas on DIY cnc stuff so building one for my garage would be fun, IMO.
  • Underwater ROV – I have never done an underwater robot before and think it could be fun. We have this sketchy pond infront of work which seems prime to stick a robot in and explore. Also the cost factor with this one is low which makes it ideal for my garage.

I think that’s a good start. Also with these projects I am going to start developing the robot webcast show Botcentric I started on last year, these 3 things seems to be a good idea for a few episodes.  As always I am going to post project updates to this site, twitter, facebook, and any other tool a stalker could use to find out what I am doing. So if you don’t see updates poke me because that means I have either gotten lazy about the projects or am sucking at documentation.


Mar 292009

Shigeo Hirose, is the director of the Hirose-Fukushima Robotics Lab at Tokyo Tech. Thanks to Gizmodo for bringing him to my attention. After having exploring his site it is very obvious to me that he and his team are by far the leading experts in robotic mechanical design. I make the specific claim about mechanical design because there are always more AI and EE developments that are non public, but seeing his work is like looking at a robotic art gallery. I can only aspire to be as good as him in my lifetime, yet I fear that I will never reach that point.

video on gizmodo.

Aug 042008

So through this little thing called my “job” I might get my hands on some of the new 36volt xrp drill transmissions and motors. Now they will be going for my new battlebot first but I could see one of these on the horizon also.