Last post by Louis L - March 30, 2018, 03:39:16 PM
For the 2018 version, we replaced the raspberry pi with a Dell laptop. The software platform is Wordpress. This provides ease of programming & a rich set of features. Limitations include the inability to run MAME from the web pages (at least not easily since this is a security feature of a web server & browser combination).
Last post by Louis L - March 28, 2018, 09:48:36 PM
A few students showed up for the debriefing. Here's what went on the white board.
Problems encountered at RIDE
Ice pick sometimes did not release cube
Drive team user errors - picking up and dropping Cubes
Arm movement is slow (not everyone agreed here. But SW says they did not max out the arm speeds)
Ice pick open/close is slow
Observation - drive team could have used a camera to better see the placement of Cubes on the Scale.
Drive team coordination and teamwork - not always in sync
Cube can fall backwards off the arm (happened a few times)
What we can do in the next few weeks leading up to BC19. In parenthesis is a number and letter. The number (1,2,3) is priority. The letter (S,M,L) is size of task. Tasks with some element of uncertainty are bumped up one size from where they would otherwise be. Boldface text is current status. Tasks that provide new functionality have higher priority than those that are improvements over something we already have.
Weight is about 107 pounds so we have 13 pounds to play with.
(2) (S) Make ice pick open and close faster (done 4/4/18, reverted 4/11/18)
(1) (L) Add climber (done 5/8/18)
(1) (S) Fix cube release (seems to be good 4/11/18)
(2) (S) Max out motor speed on arm (done 4/9/18)
(1) (M) Fix arm pot (done 4/9/18)
(3) (?) Add feedback / sensing aid for cube placement. Add camera. (done 5/7/18)
(2) (L) Add intake for faster acquisition (no longer needed 4/6/18)
(3) (M) reaching behind to drop cube (no longer needed 4/9/18)
(3) (M) narrow cube pickup (Skip)
Do not repeat past mistakes
Other things to do:
get parts / IMU (4/4/18) Ed got some belts and pulleys from McMaster for prototyping. Turns out we already have the NavX IMU)
who is on drive team? (Ben K, Pablo, Sepher, Saharsh, Gargi, Ishita)
Last post by Louis L - March 26, 2018, 10:50:53 AM
Post RIDE update. This arm worked for the most part. The most glaring problem was that it sometimes refused to release the Cube. We didn't see this happen until about halfway through the matches. We believe this happens when the Cube's fabric starts to stretch from use and when we grab the Cube where the handle lies. The circular guard plate we use to keep the nubs from digging too deeply into the Cube is getting caught on the plastic lattice behind the nylon fabric.
We tried to fix this by enlarging the guard a little bit (we have to be careful how large to make this to keep within the 16 inch rule). Finally we removed the plate entirely. This seemed to work but we would need extensive testing to prove it really is fixed. We'll also need Cubes that are beat-up to simulate the real game pieces.
Last post by Louis L - March 16, 2018, 02:27:46 PM
Update - after trying with a wooden mock-up, we found that using a spring has a drawback: when the added mass of the Cube is taken into account, horizontal movement of the arm (such as when the robot turns) shifts the force applied to the Cube by the 2 pincers. The forces are no longer even due to the robot's movement and this causes the Cube to fall out. One solution is to add strength to the spring. Another is just to lock down the pincer. We decided to replace the spring with a motor that will effectively close the pincer to a fixed position and keep it there.