Phoenix (703) 2007 Inferno III

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"Inferno III" was Team 703s robot for the 2007 FRC game Rack 'n' Roll.

Contents

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Pre-build

The Final version of the 14 Wheel Drive system used on the 2007 Chassis.
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The Final version of the 14 Wheel Drive system used on the 2007 Chassis.

In the Pre-Build season the team went over some of the things that needed to be improved upon from the previous years robot Inferno II. For several years the team had built robots with tank tread drive systems and liked them, however, there were quite a few problems with tank treads, the most common of which were treads breaking and robot jumping on turns. A new drive system was designed in an attempt to simulate a tank tread system but improve reliability by utilizing 14 tread wrapped wheels (7 on each side of the robot), all geared together and powered by a homemade 2 speed transmission.

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Build Season

As soon as the 2007 game was announced, the team started developing a strategy. It was predicted that being able to lift 2 other robots at the end of the match would be the most critical part of the game, so efforts were focused on the design of a lift system. Several designs were considered and finally a double ramp platform was decided upon. It was thought that an opposing team could potentially block out a single ramp, so two ramps were used along with a "riser" in the center that would allow robots to cross over to the platform on the side being blocked. The ramps designed required a type of mast in order to deploy, it was thought that perhaps an arm for lifting ringers could fit on top of this mast, several designs were made and one was decided on, however, due to weight issues, it was considered a secondary objective. The new drive system that had been designed in the pre-build season had many advantages, at the cost of over 60lbs in weight by itself. Due to this, the team knew that weight saving on the rest of the robot would be critical. One of the team mentors, who had had past experience with lightweight composite materials though a solar powered vehicle competition proposed to have a good portion of the robot (the ramps, platforms, and riser) constructed out of a carbon-fiber composite material. The team liked the idea and started looking for a distributor of the necessary materials. Many of the places the team looked that sold carbon fiber had very high prices and limited supplies (apparently due to various aircraft companies having a sudden demand for it). A supplier was finally found that had very reasonable prices, thereby allowing the use of the material on the robot without going over the cost limits. Building the carbon-fiber parts was very time consuming and delicate work, each piece needed to be cut to the correct size, covered in epoxy, have a piece of carbon fiber placed on it, rolled flat, covered in more epoxy, spread out, covered with a special cloth, and vacuum bagged for 6-8 hours. Though it took a good portion of the build season, the team managed to get everything done with a day left to tweak and test the robot before putting it in the crate and shipping it off. Unfortunately, the scoring arm that had been build was not finished in time to be used on the robot, the team hoped to finish it at a regional.

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Accomplishments

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Detroit Regional

The Detroit Regional showed the team some of the minor flaws in the ramp design, the biggest issue was that the wings would constantly deploy on their own in the middle of a match. The design of the ramps prevented them from extending outside of the size limit but they were still exposed to contact with other robots. This issue was solved through the use of several simple limiting parts that could only be overpowered by the motor driving the ramp deployment, this motor (Banebots motor) was replaced on the second day by a more powerful one (Globe motor) due to its inability to retract the ramps without help. The 14 wheel drive system, however, proved itself well, as the robot was able to push virtually anyone on the field. Due to the issues with the ramps, there was no time to attach the arm.


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West Michigan Regional

The West Michigan Regional was the first regional team 703 ever won. The first day of practice matches was spent assembling some robot parts that had to be replaced from the previous regional. Unfortunately this meant there was no time to get into any of the practice matches. The lack of practice showed in the first two matches on the second day as the team lost both of them. However, despite these early setbacks the team managed to pull out in 5th seed on Saturday. During the alliance selection, the team chose teams 469 Las Guerrillas and 494 Goodrich Martians as their partners. The first of the playoff matches went well resulting in the alliance making it all the way to the finals. They then won the first match and narrowly lost the second match. However, after the second match, team 703 realized that one of the idler gears in their 14 wheel drive system had come loose; unfortunately, there was no way to fix it so the team was forced to drive their robot with only 1 of the 7 wheels working on one side. The match began with a potentially dangerous autonomous mode, which, instead of going around to the far side of the rack to block the opposing teams, proceeded to drive in crazy circles on its own side, narrowly missing several high speed collisions with their own partners robots. After the autonomous mode ended the teams driver noticed that while driving the robot normally would result in the gear slipping, driving in reverse allowed the robot to perform normally (it was later discovered that this was due to the gear being pushed down into position by driving in reverse). This allowed the team to continue playing hard defense on the opposing alliance. At the end of the match, team 703 and their partners had been out scored and were not able to get on team 469s ramps on time, however, two penalties on the opposing alliance for "Home Zone Violation" and "De-Scoring" gave 703 and their alliance enough of a point advantage to win the match and thereby the regional.


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The Championship Event

The 2007 robot ramps just after deployment, and again after two robots had driven up them.
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The 2007 robot ramps just after deployment, and again after two robots had driven up them.

The first day consisted of replacing parts damaged at the end of the West Michigan Regional with new, more durable ones. Due to the discovery of the idler gears being pushed down into position and running correctly by driving in reverse after a bearing broke, it was decided to reverse the direction the robot drove in, thereby helping lengthen the life of the bearings. The first day of matches didn't go well as the team lost 3 of their 5 matches (the team blamed this partially on bad alliance pairing). The second day they won 1 of their 2 matches putting them in 50th seed (out of the 84 teams in the division). Then, in alliance selection, the 5th place alliance with teams 1712 (alliance captain) and 2056 (1st round pick) asked team 703 to join them. In the Quarterfinals, the alliance went up against teams 229, 191, and 1126. The first match, team 703 and their alliance lost, however, lairing from their mistakes in strategy, they came back to win the next two matches, moving up to the semi-finals. Then, in the Semi-finals, team 703 and their alliance went up against 503, 65, and 79. They lost their first match, won the second, and then, after a close match lost the third.


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Indiana Robotics Invitational (IRI)

(Off Season Event) general description of how it went


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Kettering Kickoff

(Off Season Event) general description of how it went

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Robot

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"Inferno III"

Inferno III is a remarkable machine in many different ways. It is team 703s first deviation from a tank tread robot in over 4 years. It features an extensive use of composite materials (about 50% of the robot) using carbon-fiber with Divinycell Foam. It was also the first time the team used a two-speed transmission in their drive system.

The base of the robot was designed to be low and heavy to help prevent tipping. In an effort to eliminate issues with tank tread systems on previous robots, the team designed and build a 14-wheel drive system, all of the wheels being powered together using idler gears. The idea was to simulate a tank tread system as best as possible without all the issues of scrubbing on turns or treads breaking. Due to the high weight of the drive system, the robots side frame was made out of 1/2in lexan to help save weight. Due to the weight limitations, the top structure of the robot, which had been chosen for a ramp system was build almost completely out of a carbon-fiber composite material using Divinycell foam for the core. The ramp system required the use of an aluminum mast on one end of the robot with a winch system to deploy it, this mast was also designed to be used for an arm for scoring tubes, this arm was built but never used due to weight restrictions. Finally, to protect the sides of the robot, standard bumpers were added.


The 2007 robot, ramps deployed on the practice field the day before shipping.
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The 2007 robot, ramps deployed on the practice field the day before shipping.
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Robot Functions and Specs

  • Drive Motors: 4 small CIM motors
  • Drive Type: 14 Wheel Tank Drive
  • Transmission: 2 speed homemade, Pneumatic shifter
  • Ground Speed: approx. 5 fps in low gear, approx. 8 fps in high gear
  • Sensors: 2 Optical Encoders, one on each side, to track robot movement.
  • Vision System: None
  • Ramp or Lift system: Yes
  • Scoring Arm: One was build but never installed due to weight limits.
  • Scoring Options: Theoretically, all 3 levels on the Rack; Room on ramps for 2 robots at 13" for 30 points each.
  • Autonomous Modes: Several auton modes that drive around the rack and attempt to bump any robots trying to score; 2 modes for each of the two used starting positions.
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Robot Strategy

  • Autonomously drive to the other side of the rack and block potential scorers
  • Play hard defense during the match and prevent opponents from scoring
  • Deploy ramps in the endgame and get 2 alliance robots up to 13" for 30 points each.


Team 703 Phoenix Links:
Team 703 | 2004 Robot | 2005 Robot | 2006 Robot | 2007 Robot | 2008 Robot

Team 703 Website

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