In pursuit of Ackerman-ish steering

I am in the middle of laying out the steering linkage for the motorcycle-engined remote control car. I decided that I wanted to try and use a low-cost, high force, linear actuator to control the steering. I can find some for a little over $100-$200 dollar range that can be controlled using serial commands. My hope is this type of actuator would be more robust to mechanical shock than a conventional RC servo. Industrial RC servos exist, but they are twice the cost for anything that I think has the torque to steer my car over rough terrain. I am also skepital of their robustness to mechanical shock. For the first iteration of the car I plan to implement Ackerman steering. The linkage typically used for approximating Ackerman steering is shown here:


I also decided, for aesthetic reasons, I would like to place the axis of the linear actuator along the longitudinal axis of the car. So now I am trying to see if this can be done in a reasonable manner. Basically I need to transmit force originating along the longitudinal axis of the car into right left motion of the coupler link of the Ackerman steering linkage. I did some thinking and I decided to make some popsicle stick models to try and spark a breakthrough. I broke out the cordless drill and got to work.

At this point, I have not solved this challenge just yet, but I did come up with some interesting things in the process. First off, a couple years ago I came up with this single DOF linkage. It was the inspiration for my new popsicle stick models.


The unique thing about this linkage is that a small angular motion at the top of the linkage results in a rapid deployment of the rest of the linkage along the medial axis. As I was trying new linkage ideas today I designed this guy.




This is a 14 bar, single degree of freedom linkage. I think it looks kind of neat. One interesting thing I discovered about it, is that it has two of the sub four-bar linkage ages that make up the composite linkage have reachable toggle positions. The picture below shows the links I am referring to.



An interesting observation I made, is that since it is a single degree-of-freedom linkage, it is possible to block the movement of the linkage simply by placing one of the two sub-system four bar linkages into a toggle position. This could have interesting applications in larger linkage systems with multiple degrees of freedom. You could essential inactivate degrees-of-freedom of the composite linkage by incorporating sub linkages that feature reachable toggle positions. You could also in some sense activate new states of the linkage by forcing the linkage past its toggle positions. I am not sure you see many complicated linkage systems around these days but I thought it was interesting. It could make some interesting artwork.

Music in Prague

Last Week I was in Prague. While I was there I was very blessed to meet some great people from the Slovak Greek Catholic Parish of the Most Holy Trinity. I am half Slovenian so I guess they are my people. They were very kind to me. They let me join them for some snacks after the daily Mass and then they let me watch the Men's choir practice. A group of the young people there even took me on a tour of the city on Sunday. The choir at this parish was really good. Here are some excerpts.

Publish Post

Mason Proffit - Were you there?

I just finished reading a biograpahy on John Michael Talbot that was on the bookshelf of our adoration chapel. John Michael Talbot visited Los Alamos last spring to give a three day retreat during Lent. I have to say he was one of the best guitar players I have ever heard. Prior to becoming a monk he and His brother Terry led a band in the late sixties and early seventies named Mason Proffit. I searched a little on YouTube and I found this great song. I decided to write the lyrics down in order to encourage jamming to Mason Proffit. A special thanks goes out to Vinnie for making the chords happen.

Mason Profit - Were you there?

Em               A
You said something should be done
C          D                Em
The way your slaves were shot and hung
              A
You said all men should be free...
C       D             Em
Were you there at wounded knee?
                  A
You were living in '42
C            D              Em
You cried when Hitler killed the Jews
                           A
You said that no race should have to die
C       D         Em
Were you there as they lie

G       D           Em           C
Were you there when they called my country down?
G        D           Em                 C
Did you see her when she finally hit the ground?
Am                      D
Could you feel the tears she shed?
C       D              Em
Were you there when Jesus bled?

Em                          A
Come all of you it's time to take a stand
C         D                 Em
You have salvation in your hand
                    A
We you need your words, we need your minds
C          D                   Em
We need you straight not stoned and blind

G       D           Em                  C
Were you there when we walked across the land?
G        D         Em          C
Was that you with the rifle in your hand?
Am                        D
Don't try to run, don't try to hide
C        D               Em
Were you there when freedom died?

G        D          Em           C
Were you there when they called my country down?
G        D           Em                   C
Did you see her when she finally hit the ground?
Am                       D
Could you feel the tears she shed?
C       D             Em
Were you there when Jesus bled?
C       D              Em
Were you there to count the dead?
C       D
Were you there...

The Harvest Begins

The growing season is now in full swing. So far some of the crops are ready for harvest. These Chiles were ready to go so I went ahead and picked them. I think I am going to try and figure out how I can get a higher yield from chiles. I would like to produce alot of them for salsa and guacamole and burritos.


These are a variety of hers I harvested. There are green onions, chives, oregano, and thyme. These herbs became spaghetti sauce.

Next I want to try growing Kalamata olive trees.

ABQ-San Diego-Berkeley-San Diego-Las Vegas -Arizona

Last week I went to San Diego to see my friend Billy graduate from SDSU. He he is in his graduation uniform. Congratulations Billy! After the graduation I had to go to Berkeley for a conference to do a poster presentation on my research. I feel it went really well.



This picture was taken on the Day of the rapture. Unfortunately when Jesus showed up he took a look around and decided he didn't want any of us. Now we are all stuck here for the time being ;-).



This is the second surfboard I made. The paint job took 50 hours to complete. I decided it was time for it to have a new home so I gave it to my friend Kathleen so she can try to learn how to surf on it.



The conference food was really great. This is the lunch desert in Berkeley




View of the bay from Berkeley




Can you guess what this is?



It is the sculpture located at the entrance of Berkeley. I first saw it back in 2005 and I really liked it so I look a picture of it.




North Beach



I liked this sculpture I saw in San Francisco



This is the door to the world champion pizza tosser's slice house in north beach. This guy takes his pizza seriously. I like his attitude.



Coit tower



Fighting sea lions



Near Fisherman's warf. I love this bay. One day I would like to sail on it.



Hoover Dam

Near the Hoover Dam Overlook



Painted Desert in Arizona



Petrified Forest National Park



Petrified trees aka Dinosaur Trees



Lots of petrified trees


Dinosaurs speak for themselves


This was a successful trip!

First part on the motorcycle car is done

I have spent alot of time working on my motorcycle car lately, and have not had a chance to report. Here I am getting some pictures so I can get a handle on what the rough dimensions of my car will be.



bushings for the rear suspension in the making.



Here are the final rear suspension bushings. Eventually they will be welded into the chassis.



I made some updates to my chassis model. At this point I have a reasonable idea how I will capture the engine and rear suspension mounting points with the chassis.



Here I am making the rear suspension pivot pin. I rescued this metal bar from the Black Hole.



Here I am putting some 1/2-20 threads on the rear pivot pin.




Today this cat was pretty vocal about wanting to join the team.



I decided to give him a shot so he could showcase his skills. Unfortunately it turns out he was all talk. I told him he might be a better fit as a gopher killer on the farm.




Here I welded a nut on the end of the pivot pin so I can tighten it up.



This is the final rear suspension pivot pin. Part one down!



The final fit up of the rear suspension pivot pin and bushings. This went together very nicely. Next I am going to get to work on the chassis members that will capture the lower engine mounting points.

The plantation is planted

The plantation is in place and ready go grow - Something's going to happen.

Cradle Surgery

Last night I was going to go ahead, and get my motorcycle engine up on the cradle so I could see what I was dealing with in terms of size. Unfortunately, when I moved the cherry picker with the engine over to the cradle, there was no way I could get the engine in place without some gymnastics. The main reason for this, was that the legs of the cherry picker would not fit under the lower longitudinal beam that separates the upright beams on the cradle. I decided I was going to have to break down and do some modifications to the cradle. I decided the beast thing to do would be to remove the lower longitudinal beam on the cradle, and replace it with some rectangular tube placed higher up on the uprights so the cherry picker legs could slide right under it. I would also remove the two lower triangulation members, and I would flip them upside down so the would intercept the new rectangular tube longitudinal members.

At this point I was thankful for all the trips I took to the flea market buying tools.




This project took most of last night and a few hours tonight, but it is now done. I am pretty happy with how it turned out. The modified cradle also has improved torsional stiffness because before the torsional stiffness was only provided by the longitudinal channel member. The two rectangular tube sections display noticeably more torsional stiffness.




Once the cradle was put together I pulled out the cherry picker again and got the engine in place. The cradle seems to take the load no problem. That engine looks alot bigger when it is at working height.



Here you can see the engine, and the rear portion of an ATV I will use for the rear suspension. The legs of the cherry picker fit under there no problem. This is nice because now I should be able to align the hook of the cherry picker with the CG of my motorcycle car very safety and easily. I am glad I took the time to do this.

Maybe its a plant holder

I am getting closer to implementing my ideas from a previous post in steel. Here is my current product hanging from the garage door opener. This is mild steel that I cut and then formed using a tree stump and a piece of log. Then I MIG welded it all together. Originally I thought it might be a table but now I am thinking it could be a nice tool holder, or maybe even a chandelier. Time will tell. I am not done with it yet.

atomistic

I felt I needed some inspiration last weekend so I cut up my empty cereal box and started making these shapes. My hope is to implement some of these ideas in furniture or pinstriping. I did do some work on my truck and it is running nice, so it may be time to lay some lines down on it. First I need to come up with the right design though. I think this exercise might convince a muse to show up.



All these shapes are made up of combinations of this atom.