DEWBOT IV
Building DEWBOT IV in 2008 to play Overdrive (Game animation)was one of our toughest challenges.
DEWBOT IV utilized a unique Fork-Lift / Catapult scoring mechanism which was able to:
- Knock Trackballs off the Overpass by simply driving underneath (fast)
- Pick Trackballs up off the playing surface
- Possess Trackballs
- Catapult Trackballs over the Overpass; and
- Return Trackballs to the Overpass at the match end for bonus points
This year, for the first time in our Team’s history, our Robot was by-in-large designed prior to building. We used Autodesk Inventor during the design process. A sub-team has been trained in its use and developed experience during the design process.
Team 1640 faced a number of daunting challenges during the 2008 build season.
The most severe of these was the temporary loss of the Team’s founder, leader and Head Mentor, Paul Sabatino, following essential back surgery early in the season. Mr. Sabatino is recuperating and we are all looking forward to his return next year.
The team also had to deal with a Teacher’s strike, which forced us from our home at Downingtown East High School for a full two weeks during the build season. The night before the strike, we all assembled at the school and loaded Robot, parts, supplies and essential tools (including a drill press, belt sander and a band saw) into parents’ mini-vans to relocate our operations. Fortunately, a local family, the McFaddins, became aware of our plight and very graciously loaned us the use of their stable as a workshop for the duration of the strike.
Contents
Design Details
Drive Train
- DEWBOT IV’s drive-train is 2-wheel drive (the rear wheels are driven) with a 2-speed transmissions powered by 2 CIM motors each to provide both speed for laps and fine control for catching and placing Trackballs. Driven rear wheels allow us to recover by reversing should we become hung up on the Overpass. We’ve put Omni wheels in the front for agility. Arcade steering (single joystick on the Operator Interface) is employed.
Lift - Catapult
- DEWBOT IV is unique in combining a Fork-Lift with a Catapult mechanism. The combination provides the benefit of allowing the robot to remain entirely below the Overpass while hurdling the Trackball over it. We can therefore hurdle on the fly, without having to stop or slow down.
- To pick up the Trackball, the Fork drops down to a few inches from the ground and level with it. We need to drive the robot so that the Trackball is between the Fork arms. When we do, an ultrasonic sonar sensor detects the Trackball and the Fork is automatically rotated up 20 degrees to capture the Trackball.
- DEWBOT IV’s lift also extends above the hurdling height, allowing us to place a Trackball on the Overpass at the end of a match for bonus points. This also allows us to knock off an opponent’s Trackball.
- The fast method for us to remove a Trackball from the Overpass, however, is to set the Lift to “Hurdle” and drive under the Trackball. Flexible tabs on the top of the Lift will push the Trackball off the Overpass.
- All of the Lift operations are controlled automatically. When planning our game-play, we were able to define eight discrete and unique logical states, or modes, for the Lift. Each of these eight modes combines a specific lift elevation together with the logical states of the three sets of air cylinders that control the Fork and Catapult operations. The operator selects between these eight modes via buttons on our Operator Interface.
Hybrid Mode
- Utilized a gyroscope chip and an optical encoder on a drive wheel to cross lines during Hybrid Period. Only moderately successful. Gyro steering was very slow and jerky. Gyro-free was fast & scary. We could reliably cross one line, occasionally two.
Pneumatics
- Used (4) solenoids and (8) cylinders (all L & R). Since all cylinders were 3/4" diameter and modest stroke (8" max), a single Clippard storage cylinder was adequate for storage. Dewbot IV has an on-board compressor. One Clippard only, which was quite adequate.
- Open the Microsoft PowerPoint Pneumatic Lesson.
Weight
- The picture says it all. Dewbot IV had a weight problem. The Fork-Lift-Catapult was not lightweight.
- On 2-Feb, we discovered the robot we were building would be seriously overweight. Fortunately, we had a good Bill-of-Material (BoM) worksheet which enabled us to develop weight-reduction options overnight. As you can see from the worksheet, the savings were substantial. Most (but not all) of the options were executed. Many were executed on 3-Feb (robot diet day).
From 2-Feb on to shipping (and afterwards throughout the competition season), robot weight was always front-of-mind and monitored very closely. Any changes made to the robot required a weight analysis and a remediation plan if the change increased weight.
Bumpers
- Bumpers were something of an afterthought with too little thought. These bolted on through the KitBOT rails and required bolts way too long (because the next standard length down was just a touch too short). Tool access was terrible. Removing and reinstalling bumpers for inspection took bloody forever. "Nuts" in plywood tended to fall off into the bumper, requiring rebuilding.
DEWBOT IV Control
The control system was pretty sophisticated and was designed to be an assist to the operator as much as possible. The base was tank drive, a long time favorite of Downingtown Area Robotics drivers. The fork-lift-catapult system could either be under manual control via a joystick, or moved to preset positions at the touch of a button.
The autonomous mode was set up to move forward under gyroscope control and a preset distance turn left. There were issues with initial setup so one line, with an occasional two lines were possible.
Competitions
DEWBOT IV attended six competitions in 2008. The links below will take you to the details of each event.
- Connecticut Regional
- was our first 2008 official event.
- Philadelphia Regional
- was our second 2008 official event.
- PARC XI
- We were alliance captains at this first off-season competition
- Monty Madness
- Received the Team Spirit Award.
- Duel on the Delaware
- We were Finalists!
Other Events & Outreach
- 2008 Team Picnic
- May 15 at the Pennsylvania Live Steamers in Rahns, PA.
- Uwchlan Day
- July 12 at LYA Fields.
- Robotics Demonstration at Sugartown Elementary & assistance with JFLL launch
People
See our other robots in the Robot Archives.
