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Official Website Of Team 14496 Roboctopi

Mechanics

At the beginning of the season, we decided that we were going to give each hardware member ownership of different sections of the robot to work on to improve our efficiency. This allowed us to have an expert responsible for the design and maintenance of each system and to prioritize tasks easily. Every major system had a customer to ensure each system worked well together and that they fulfilled all requirements. For example, the Frunk team customer was the dunking arm team so the requirement was that the Frunk could deliver minerals to the dunking arm with high reliability. We used a modified form of SCRUM to organize and plan tasks and to prioritize the order in which systems were built and given resources and manpower.  This is how we organized our mechanics team: Alex took ownership of the Chassis and the Drive Train/Tracks, Cannon took ownership of the collection mechanism (Frunk) and latch (Falcon), and Nico took ownership of the delivery mechanisms (Cookie jar, the Dunker and finally Project Opportunity).

Drive Train/Tracks

 

Part Name: First Tracks    Revision #: Mark 0 Date: November 9, 2018

Materials: Tetrix beams, Makeblock tracks and sprockets







First design idea: We began by experimenting with a rubber track system made by Makeblock we already had.

Purpose: The purpose of this design was to start learning about the materials that we had available and how to use them. We also wanted to determine what challenges we’d have getting inside of the crater. We quickly determined this was not a viable solution because these off the shelf parts were not strong enough to survive an entire season.

Part Name: Track System       Revision #: Mark #1-3 Date: 9/23-30/18

Materials: 12”x12” 7.5mm Delrin sheet 5x, 55mm M4 screws and and nyloc nuts x80, 2x Tetrix Torquenado motors and tetrix beams

Obstacle encountered (With Mark 0): After testing the track system, we realized that these tracks were not going to last us very long because they were made of rubber.

Solution: Subsequently, during a team discussion, we came up with 2 alternate designs: an omni wheel drive system with 4 motors or a 2 motor laser cut track system made out of delrin. After further discussion, the team decided that the laser cut track system served our game strategy far better that the omni wheel system.

Purpose of change: Build a track system that is going to last a whole season and give our robot access to any part of the field.

Obstacleencountered (With Mark 1): When we laser cut and tested Mark 1, we noticed that the lip on the inside link (see fig 2 mk 1), which was designed to hold the track on the sprocket, was causing the track to interfere and bind.

Solution: We chose to remove this lip.

Purpose of change: Tracks were binding because the lip on the inner link of the track was catching on the sprocket.

Obstacleencountered (With Mark 2): When we recut and rebuilt the tracks in wood we realized that the tracks were going to weigh a lot in delrin because the delrin is heavier than the wood we were using for the prototyping. Also, when we put rubber on a couple of links of the tracks, we noticed that the recesses for the rubber were too deep so the rubber was not giving us any grip.  

Solution: To reduce the weight of the tracks, we cut holes in certain parts of the links and sprockets but we did not compromise the strength of the components. Additionally, we made the recesses for the rubber shallower to allow the rubber to give us the grip we needed.

Purpose of change: To reduce track weight and to improve track grip.

Tracks after Mark 2 changes

Obstacle encountered (With Mark 3): When we started driving the robot with the Mark 2 tracks, it worked great until we tried getting inside of the crater. When we tried getting in the crater, the idler wheel in the tracks kept causing the robot to tip over.

Solution: We chose to remove the idler wheel to give us better crater entrance and exit.

Purpose of change: The robot was tipping over when we tried to enter the crater.

Final Track Design:

Collection “The Frunk”

 

Part Name: Collection system          Revision #: mk. 0 Date: 27 October, 2018

Materials: 2 angular servos, makeblock parts, 1 Tetrix motor

First design idea: Separate collection system from the main robot that can fold down and collect minerals and hold them until they are ready to be deposited into the delivery arm basket. Also, it will be able to expel unwanted minerals from the system.

Purpose: To collect minerals with both accuracy and speed. Also to be able to sort through unwanted minerals in order to obtain the desired minerals.

 

Part Name: Collection System     Revision #: Mk I Date: 3 November, 2018

Materials: tetrix motor, C bracket, spacers.

Obstacleencountered: Servos didn’t have enough torque to lift the collection system.

Solution: Mount a tetrix motor to lift the system up and down.

Purpose: The purpose of the change was to have enough power to easily lift and lower the collection system for both driver controlled and autonomous periods.

 

Part Name: Collection System    Revision #: mk. II Date: 11 November, 2018

Materials: belts, gears, tetrix motor

Obstacle encountered: Having the motor on top of the sweeper reduced the ability of the lifting motor to get the collection system off the ground. This was due to the weight being the farthest possible from the axis of rotation.

Solution: Move the sweeping motor from on the top of the collection system to below the structure of the collection system in order to bring the weight of the motor closer to the axis of rotation. Also, we used a belt to connect the motor to the sweeper.

Purpose:  Make it more efficient for the motor to lift the collection system. Also give a more smooth lifting and lowering motion for autonomous and driver controlled periods.

 

Part Name: Collection system   Revision #: mk. III Date: 16 November, 2018

Materials: andymark 30:1 motor

Obstacle encountered: Tetrix motor used for the sweeper would not spin fast enough to collect gold minerals.

Solution: Switch the 60:1 100 rpm tetrix motor to an Andymark Neverest orbital 20:1 340 rpm gear ratio high speed motor.

Purpose: The purpose of the hardware change was to make the sweeper spin faster allowing the robot to collect cubes for the driver controlled period.

 

Part Name: Collection system     Revision #: mk. IV Date:

Materials: custom 3d printed sweeper to axle mount, flat irrigation tubing

Obstacle encountered: Two brushes are not enough to collect cubes.

Solution: add two more brushes for a total of four.

Purpose: To allow our robot to collect both types of minerals effectively.