Process
|
Kickoff
|
The 2007 FIRST Robotics kickoff occurred on Saturday, January 6th. The entire team met in the "Cybersonics Building" to watch the kickoff (via satellite). Plans were made to meet on the following Monday to discuss the game and begin our build season. That night, the entire team was asked to go home and read all the rules in order to completely understand the game.
The object of the game is to score as many points as possible by putting inner tubes on a center rack. At the end of the game, if one or two robots are lifted off the ground, bonus points are awarded according to the rules given by FIRST.
|
|
|
|
|
|
Brainstorming
|
On Monday, the team talked about game strategies for playing the game. The team discussed activities that will happen throughout the year and the mentors introduced the work ethic to the new members. The Inventor crew began drawing the drive system, which was previously decided to have a six-wheel drive system before the build season began.
The team had decided on the following Tuesday that the robot should exhibit the following strategies:
Speed
The ability to lift up two robots
The ability to put tubes anywhere on the center rack
|
|
|
|
From brainstorming, the team moved onto conceptualizing the major robot operations.
The team decided to focus on lifting two robots off the ground while at the same time designing an arm to lift and drop inner tubes onto the center rack.
|
| |
Chassis & Drive
|
|
Click Here To Go To Final Design Page
|
|
|
This year, Cybersonics team 103 decided to use a six-wheel drive system after experiencing the frustration from last year’s two-wheel drive’s lack of pushing power. Hopefully with this year’s drive-train, we will be able to do more than our fair share of pushing, since we couldn’t do any of that last year. The main feature of the drive system is that all the wheels are driven and are connected via spur gears encased in a housing. This housing was made by a mentor who has access to a CNC milling machine.
|
|
At an off season event, we saw a new wheel design made by AndyMark and we decided to order them. They are 6" machined aluminum wheels. We took the spur gears and had them turned down from ½" face to ¼" face in order to reduce the weight. The gears are held onto the wheels via bolts that were put in the wheels by AndyMark. When all was said and done, with each side completed, it only weighed 9.1lbs. Aside from the weight, another advantage to this system is that the robot turns on its own center axis. To achieve this feat, we experimented with different offsets for the center wheels and finally decided on 1/10" offsets which still allowed us to turn on our axis, but eliminated almost the entire forward and backwards rocking that you would expect. This system does not have any of the problems that normally would be associated with six-wheel drive. There is no jumping or bouncing when turning and the wheels have just about zero play from wheel to wheel.
|
|
There is only a short piece of chain running from the transmission to an intermediate axle. This fact, combined with the AndyMark two-speed transmissions, made this year’s robot very fast and agile. There really is no disadvantage to this drive-train, except that it was expensive. Throughout the competition we will keep an eye on it to see how it wears and what weak spots (if any) there are.
|
|
|
| |
| |
| |
Arm Gripper Design
|
|
Click Here To Go To Final Design Page
|
|
|
The arm gripper design went under a lot of discussion and different design ideas. Team members met and discused many different attributes for how it should be put together.
The secret of the 2007 Cybersonics robot is its smooth ability to pick up tubes off of the field. The final design was chosen because of its compact and light-weight design. Shown here are the calculations our team used to derive how our final design was to be put together. (Click Picture for larger image)
|
|
Team members in the manufacturing and inventor groups prototyped their own arm designs. Five days of prototyping went into the design of the gripper system. The following ideas were created:
|
| |
|
Prototype 1 : Inner-Grab Design
Click Picture To view Video
|
|
|
The Inner-Grab design stresses the idea of picking up the tube by going into the center of the ring. The mechanism will start in a position where the arms are close together then enter the tube, and finally extend the arms out to grab the ring.
|
|
|
| |
Prototype 2 : Outer-Grab Design
Click Picture To view Video
|
|
|
The Outer-Grab design stresses the idea of grabbing the tube from the outside of the ring. Two arms would be extended beyond the diameter of the tube and push in on the ring.
|
|
|
|
Prototype 3 : Under-Grab Design
Click Picture To view Video
|
|
|
|
The Under-Grab design will have one moveable arm and two stationary arms. It stresses the idea that the ringer will be grabbed by two stationary arms on the outer edge and the moveable arm will grab the ring from the center.
|
|
|
| |
| |
Overall Consensus
In 5 days, the team decided to use the Under-Grab design because of the ease of the idea's use. The Inner and Outer-Grab designs were flawed because the systems would have trouble putting the ringers onto the center rack. They also have the possibility of getting caught on the spider or another robot.
|
| |
| |
Lift System Design
|
|
| |
|
|
With lifting the two robots off the floor, we distinguished two basic ideas. The first was a forklift idea where the robots are being lifted by a forklift. The other idea is having a pulley system, in which one or two robots only drive a partial way onto the ramp and pulling the ramps up by use of a pulley.
When putting the tubes onto the center structure, we want to lift the tube above a scoring pole, parallel to the poll and drop it onto the scorer.
|
|
We believe it is ideal to have a tube grabber that can pivot the tube at any degree off the ground. As a side idea, we thought about having the same tower (if there’s a tower) to fold down to double as a ramp for a robot to drive up on. Pretty much, we want a transformer: a robot to fold out into some kind of design to put tubes on the center structure and lift other robots off the ground. The manufacturing design team decided to keep the transmission gearbox from last year, driving a three-wheel drive gearbox by #35 chain.
|
| |
The Ramp Idea
Click Picture To view Video
|
|
|
We had thought about the idea of including a ramp on the robot. No designs were actually built in the design process. However, we had modeled this design in Inventor to present the idea to the manufacturing team. We imagined a ramp that could fold up into the robot and somehow come down to hold two robots. The trouble was finding a design that had an arm to put the tubes onto the rack and have a ramp that would allow two robots to drive up onto, off the ground.
|
|
|
The Forklift/Lift Ideas
Click Picture To view Video
|
|
|
|
The design crew had come with two major ideas: a forklift that would pull a robot up by use of a pulley system and a lift system that another team could drive onto and be lifted off the ground. The team had chosen to go for the lift idea when deciding between the two because of its flexibility to lift a robot up to a preferred height. The forklift idea was thought to cause too much of a problem for other robots and they might damage our own if another team's robot falls onto ours.
|
|
|
| |
| |
| |
A Change in Direction: The End of the Lift System
|
| |
|
|
We had trouble with the physics to add systems for counterbalance and we already had weight issues. Originally, we wanted to have an arm that could utilize the use of our fast drive system. We then realized that if we got the lift system to work, we would not be able to have an arm to lift the tubes onto the center rack. We met as a team and came to the decision to drop the lift system idea and to concentrate on designing a great gripper and tower system.
|
|
A lot of problems were arising from the dual lift-and-gripper design. The team had realized that the lift system we were creating weighed a lot. The system had to be created out of 8020, where we had created it out of Bosche. A lot of weight issues had come from the design we wanted to have in order to lift two robots off the ground. At the time, we had created a great gripper design to lift the inner tubes off the ground, so we decided to have a tower and arm system that could extend to all the levels of the center rack. To have a better view as to why we dropped the design, Click the Pictures below to view our stress analysis of the lift system design.
|
| |
|
|
|
| |
