Two and half weeks left

Super Sunday night and we have two weeks and two days left until ship date.  I have not posted for a while in regards to the progress of the robot. 

Drivetrain

We have decided on a robot that drives wide instead of narrow.  The drivetrain will be 6" mecanum wheels on individual suspension.  The suspension for each pod consists of two metal plates joined on the interior edge by a hinge. The outer edge will have two springs between the two plates.  The top plate will be mounted directly to the robot chassis.  The bottom plate will have the wheel mount and the AndyMark Toughbox mounted on it.  This will provide suspension on each corner of the robot. 

Chassis/Bumpers

The chassis is the kit of parts chassis provided by AndyMark but we made modifications to the T Brackets to allow for the Toughboxes to be located below the chassis.  We have two set of bumpers: one red and one blue. Both sets are identical with front/back and left/right sides interchangeable.  This will make it easy to change bumpers and not be concerned which one goes on a specific side.  The bumpers are designed with a 1/4" stud for inserting into the chassis frame.  Two 1"x1" angle pieces are mounted to each bumper.  A 1/4" Cleco is used to hold the bumper in place thru a 1/4" hole in the top of the 1"x1" angle.  Numbers will be stenciled on each of the bumpers.  

Kicker

The kicker mechanism will mounted on a hinge on the front of the chassis.  The kicker frame is made of 80/20 (see below) purchased from McMaster Carr.  The arm consists of 1/4" aluminum plate (see below) with a powered roller for contacting the soccer ball.  The roller is powered by a FisherPrice motor with a Banebots transmission connected by #35 chain to the roller.  The roller has an AndyMark #35 aluminum sprocket with 4 Banebots wheels mounted on the shaft.  The shaft can be ran forward, backwards or with no spin at all depending on the desired kick of the ball.  The kicker will be powered by surgical tubing attached to the kicker arm and the chassis and loaded by an AndyMark Supershifter with the high speed gear removed.

Bot Top

The bot top will be made of a carbon fiber top covered with slow recovery foam.  The top is angled with a 3" drop from back to front.  It is also angle from each side to the middle to create a pathway for the ball to exit off the front of the robot near the middle of the robot. The top also encloses the Axis M1011 camera for locating the vision target. The carbon fiber top was chosen as the top for two reasons:  light and can be custom shaped.  The carbon fiber provides a light weight top that is custom shaped to our robot thus providing the ability to direct and control the ball path as well as have little effect on the robots center of gravity.  The bot top also leaves room at the back of the robot for the lift mechanism. The top was made by cutting insulation foam into 1' x 3' segments.  The segments were then glued together with Loctite Spray Adhesive  The block was cut into a smooth rectangle slightly smaller than the original size of 1'x3' with a hot wire cutter.  Foam was glued on the top to build up the back to the height of 17".  Cutouts of MDF were made to use for cutting the foam with the wire cutter  The MDF cutouts were adhesived to the front and back to guide the hot wire cutter(See the big pink foam cutout below).  It shows the form that was cut using the MDF form. The foam was covered in sheet rock mud and allowed to dry. The next step will be to sand the form smooth to prepare it for the seal that will be smooth.  The carbon fiber will be laid on the sealed form and then vacuum sealed.  

Bot Tub

The tub will be made in a similar way to the bot top but pieces of foam will be individual cut and glued.  The shape of the tub is dependent upon the kicker, motors and transmissions located below the chassis.  Carbon fiber was chosen for a different reason that the top: strength of material.  The carbon fiber will provide a strong mount for location of the battery at the lowest point possible and as close to the center of the chassis as possible thus helping with the center of gravity of the robot.  Our center of gravity is important in regards to attempting to traverse the bumps on the course.  The electronics will be mounted on the carbon fiber tub as well.

Lift Mechanism

The lift mechanism will be powered by a FisherPrice motor. A fiberglass pole will be mounted in one corner of the robot and be bent with a cable that is attached to the FisherPrice winch. The motor will release a cable used to bend the pole. The fiberglass rod will flex upright with a hook at the top of the pole attached to the cable.  Once the hook is placed on the tower, the winch will be reversed to lift the robot off the ground.  

Vision

The vision system will consists of three different cameras. One camera will be mounted on the top of the robot for vision acquisition.  Two cameras will be mounted below the chassis for ball location.  An onboard microprocessor will be used to process the images from the three cameras.  

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