I wanted to post some follow-up to the Peaucellier 12 bar hybrid lift linkage that I proposed last Dec when 1508a was working on it. I never showed a picture of it. Here is a bog post summarizing its performance at Vex Worlds.
I will post some additional documentation on the robot construction after the kids get it done.
I’m not sure the team had much advantage over a traditional 4 bar but it was fun to build:)
I saw this robot while watching the big screens, and when I first heard it was being built was very excited! It’s too bad your robot had problems in the competition, but you guys still did something quite amazing! I’ve never seen a lift design quite as cool as this. Josh/Titan/1103’s lift was cool, but I can’t really say it’s as unique as this one. Great job you guys, for building it, and making it work. I’d really love to see a video of it in action.
It looks like there are a total of two four bar linkages and the PL linkage. The two linkages use PL links and some extra metal in order to preserve orientation. There has to be two because otherwise a single link would keep a constant length which the application doesn’t call for.
When i saw this robot at a regional competition i thought it was like any other claw robot. After qualifing they were ranked 4th and were picked by the 1st seed. Though we wanted them to be on our alliance, we moved on and got picked by the 2nd seed. They owned dominating the quarter and semis. In the finals it was us against them. We took the first match but lost the autonomous because of the prescore they had. This was the first time i saw a prescore and i was amazed. We lost the second match because they stopped us from hanging. And the last match was so close we litterally won by 5 points (less than a tube). Both teams were shocked as our ally descored their winning tube in the last second. Though we won the tournament, you better believe that when they won the design award our entire team stood up and cheered them. After the final match me and the drivers went over to 1508 and said great job and gave them a great hand shake. After the tournament i went over to their robot and i looked at it and i was confused on how it lifted. I talked to them and i loved their lift, man this team is and epic, epic win and i hope to see them at all the regional events next year. I hope next time were ranked first or their ranked first so we can pick each other. Good job 1508 .
Here is the Excel file. I use excel for rapid prototyping of 2D designs. Guess it seems easier than using solid works for me. I use the formatting to scale the drawings and objects and it is nice to have the calculations of a spread sheet handy.
The key design feature is the marriage of a desk lamp with two links in common with the Peaucellier to keep the lift vertical. The left side is a copy of the right side and joined at every joint with axle bars for lateral stability so it is really a 24 bar lift. The tricky part is getting the spacers and bearing blocks to fit nicely since some joints have six links coming together. Also keeping the weight down with just the right type of links.
The lift balances nicely and is very responsive to autolift commands. We will show this in the video when its made.
@Clean Sweep Man… thanks for the kind words. I don’t recall getting a design award for this though it might have been worthy of one:)
My bad, obviously I did not look at the picture of their robot carefully enough. It does look like they have a 4-bar added to the Peaucellier Linkage. Though it looks like the only way they keep the claw parallel is with the wires at the top. Is there something I’m missing?
[EDIT]Never mind, looking at the PowerPoint I see a better picture that shows the extra bars at the top creating the “Desk Lamp” 7-bar.[/EDIT]
The object is to make the lift move straight up and down while maintaining the claw orientation (ie jaws parallel to the floor). The 7 bar desk lamp can maintain the claw orientation but you must control the interior angle of the desk lamp properly if you want it to move straight up and down. Peaucellier design offers a way to do that with planar linkages.
@DK I originally had in mind a hybrid which used a claw and needle or the use of an exterior tube collector like 599B used on their slides. But, the kids wanted to use a claw. I think they were influenced by 599A 4bar+claw which I gave them to model their drive train/lift drive after since they only got started in Dec. That way if the Peaucellier didn’t pan out, they had a ready fallback to a design similar to 599A which was a top performing robot in regionals. 599A team certainly deserves some credit for those aspects of the 1508a robot.
I know the idea is to keep the motion linear. My team had the same goal this year given the game. I was just wondering why you chose one method of linear motion over the other, but now I understand your reasoning now about why you chose peaucellier. Also, it is likely given the amount of slop associated with the use of many gears that the desk lamp design would not be able to maintain linear motion as easily.
although the main advantage of this lift is to have linear motion, i cant see may teams doing a more “complicated” design than giving their driver a few more hours of practice
it LOOKS cool though, and i liked how the 1x25’s you used didnt warp or bend
agreed. although with this year’s competition there isn’t much of an advantage with a linear lift. Last year though, especially with our spear, it was so much easier with a linear lift. Although we used a lift mechanism similar to that of 1103 it served the same purpose.