Blog - March 2010


We won. Woo!

We brought home the entire super structure/arm as part of our withholding allowance. We will be working on the kicker and tying to make it more consistent. There were some issues at SVR where a “Middle” distance kick would just kind of putt the ball forward. You can see that happen in this video at 1:50ish.

We will also be working on refining the arm, and making it hang faster. Yay for continuous improvement.

Possible causes for kicker inconsistencies:

1. Balls being grabbed too hard – When ramming balls into the wall, it is possible that the ball is being grapsed so hard that the kicker has trouble ejecting it from its grasp. After initial auton testing on Thursday, the code was changed to remove the slight roller pause during kicking, which likely was previously releasing the tight grasp on the ball, giving a more repeatable kick. When testing on the practice field, we were gingerly placing the ball into the roller before kicking. This differed greatly from on field interaction, as more often than not the ball was rammed into the wall or bump, forcing it further into the roller and causing it to grab very hard.

2. Who knows? I will put money on cause #1 – TC

More Autonomous Development

Here is the idea for SVR auto modes:

1) Far Zone – Shoot 3 Balls – Long Kicks
2) Far Zone – Shoot 3 Balls – Bounce kicks in middle zone (more accurate shots, but more chance of ball hitting partner)
3) Middle Zone – Shoot 2 Balls – Start touching tower and go in at angle
4) Close Zone – Shoot 1 Ball – Start touching tower and go in at angle

Number 2 is working as of tonight. It can consistently hit 2/3 shots, but with a bigger field I imagine this will be better.

Bumpers, and practice/development

Today the bumpers for team 254 were completed and are currently en-route.  The embroidery looks great.  The bumper tubes may need to be milled slightly in width, to account for thicker-than-expected fabric.  This would allow the attachment pins to insert into the robot further, if they do not quite reach.  A couple members from team 968 will be spending the weekend at the 254 lab, to install revised components, practice driving, and develop code.

Beginning Competition Preparations

Preparations for Competition next week have begin. Numerous teams of students have been working hard to complete the Competition Robot’s superstructure, which will be carried in as part of the withholding allowance. Several students worked to complete a bill of materials and plan out the packing of the crate from Silicon Valley to Las Vegas. Batteries have been ordered.

Bill of Materials

Autonomous Development – Part 1

(There was a video here that has sadly been lost in the archives.)

It’s a start…

Kicker Testing

Kicker testing continued today, after a series of mishaps with the arm last night.  We found that we could shoot well from midfield and poorly from either extreme with the current configuration.

We milled the kicker plate down by 1/8″ from it’s already shortened state to make it a total of 5/16″ shorter than designed.  With the new length we can now shoot extremely repeatably from midfield, well from anywhere in the far zone, and well from the back third of the home zone. 

Videos below demonstrate the kicker at various positions on the field. Any variations in kick distance are due to varying air pressure of the balls.
(There was a video here that has sadly been lost in the archives.)
(There was a video here that has sadly been lost in the archives.)
(There was a video here that has sadly been lost in the archives.)
(There was a video here that has sadly been lost in the archives.)
(There was a video here that has sadly been lost in the archives.)
(There was a video here that has sadly been lost in the archives.)

Position 0: 13 Encoder Counts
Position 1: 16 Counts
Position 2: 18 Counts
Position 3: 23 Counts

Robot Progress

We field tested the final design of the Gyroscope assembly at the Proving Grounds. During this test, we also tested the robot “Drive Straight” software routine. This works like money.

Earlier in the day, students and mentors joined the superstructure to the drive base. We then calibrated our kicker system. We still need to add the 3M self fusing electrical tape to the ball roller assembly and properly tension the kicker.

We’re far behind 254, but after today, we’re now in better shape.

Bumper Progress

Foam pool noodles have been affixed to all 8 bumper assemblies.  The fabric for all the assemblies has been cut, and sewn in the corners.  The fabric is currently at the embroidery shop.  Currently, we expect to receive the 254 fabric pieces back on Saturday 3/6.  They will then be adjusted for fitment, and permanently assembled to the bumpers.  The 968 bumper assemblies will follow suit next week.

Roller Improvements

Today, several improvements on the roller assembly were completed. The holes on both roller plates were hex broached to accommodate a new lower roller. A design flaw in the previous design allowed the lower roller to free itself and spin in a direction that did not allow the robot to properly hold the ball. A new shaft was completed. Additional shafts for the remaining robots will be manufactured in coming days, once the design is tested.

Work continued to tune the kicker positions for accurate ball scoring. With our 128 count encoder on the kicker, it zeros itself on every kick and is able to winch back accurately each time. The trampoline springs provide extremely repeatable force (as long as ball pressure is consistent). We have been working to tune the number of encoder counts which the kicker must winch back for optimum scoring from any point on the field.

New Plates!

Today, the second prototype plates to replace the hard stop plates were completed and installed. These plates included mounting provisions for attaching three trampoline springs to power the kicker and allow the arm to stow properly, two features not included in the initial prototype. Four full sets of these plates will be manufactured as soon as the material arrives and will be anodized for final robot use.