Issaquah Robotics Society 1318 Issaquah High School - Washington. Engineering Notebook 2018 Season

Transcription

1 Issaquah Robotics Society 1318 Issaquah High School - Washington Engineering Notebook 2018 Season

2 Table of Contents 1. Engineering Story 2. Our Product Cycle 3. The Game Summary Tasks & Points 4. Strategy Development Game Analysis Autonomous/Teleop Strategy Practice Robot Approach To Design 5. Hardware/Mechanisms Climber Intake Elevator Drive Train 6. Electronics & Pneumatics 7. Software Architecture 8. Scouting Network 9. Support 10. Our Sponsors

3 Engineering Story One of the goals of FIRST is to encourage students to apply the engineering process to various problems. IRS Team 1318 believes that engineering is about developing and implementing a design both effectively and efficiently. We incorporate the engineering process into the design process for the entire robot, integrating engineering into entire meetings instead of just using this process for specific tasks. We used the same adaptability and change required to be a good engineer to organize and run our team this year and accommodate the new FRC game challenge. To keep the design of the robot progressing, we organized into various sub-teams, each responsible for their own tasks which were then integrated into the whole robot. The effective communication between our sub-teams allowed our robot to be designed and built with such precision that we were able to swiftly create a nearly identical second robot for competition use. 3

4 Our Product Cycle To ensure efficient and effective engineering we follow a product cycle. This allows to continuously improve our robot while following a reliable process. Brainstorming 1. Establish a strategy for the game. 2. Determine the most important tasks. 3. Conceive mechanisms that fulfill the tasks. Design 1. Build CAD and physical mechanism prototypes. 2. Arrive at consensus on preferred designs. 3. Fine-tune and iterate prototype designs. Build 1. Assemble practice robot from prototype designs. 2. Test & refine practice robot. 3. Build competition robot based on practice robot. Robot Evaluation 1. Test each mechanism separately. 2. Run robot through integrated tasks. 3. Practice with competition robot at field. Post-Competition Analysis 1. Analyze recruitment, training, and build season. 2. Evaluate student leadership models. 3. Review our design and engineering processes. 4

5 The Game Summary* FIRST POWER UP, the 2018 FIRST Robotics Competition game, includes two alliances of video game characters and their human operators who are trapped in an arcade game. Both alliances are working to defeat the boss in order to escape! Each three-team alliance prepares to defeat the boss in three ways: 1. Control the Switches and the Scale. Robots collect Power Cubes and place them on Plates to control Switches or the Scale. When the Scale or their Switch is tipped in their favor, it is considered owned by that Alliance. Alliances work to have Ownership for as much time as possible. 2. Earn Power Ups. Robots deliver Power Cubes to their humans who then place them into the Vault earning the Alliance Power Ups. Alliances use Power Ups to gain a temporary advantage during the Match. There are three Power Ups available to teams: Force, Boost, and Levitate. o Force gives the alliance ownership of the Switch, Scale, or both for a limited period of time o Boost doubles the rate points are earned for a limited period of time o Levitate gives a robot a free climb 3. Climb the Scale. Robots Climb the Scale in order to be ready to Face The Boss. During the remaining 2 minutes and 15 seconds of the match, the Teleoperated period, student drivers control Robots. Teams on an Alliance work together to continue to control their Switch and the Scale. They can also trade in their Power Cubes for Power Ups. During the final 30 seconds, teams work together to Climb to Face the Boss. Alliances are seeded in the Qualification tournament using ranking points which are awarded based on a combination of their Win-Loss-Tie record (2 points for a win, 1 point for a tie), the number of times they achieve three Climbs (1 point), and the number of times during Autonomous they complete three Autoruns and gain Ownership of their Switch (a.k.a the Auto- Quest) (1 point). 5 *The summary above was extracted from the 2018 FRC Game Manual

6 The Game Tasks & Points Autonomous Tasks Definition Value Cross Auto-Line Robot crosses Auto Line 5 Switch ownership Tipping a Switch in your favor 2,+2/sec Scale ownership Tipping a Scale in your favor 2, +2/sec Teleop Stacked Tote Tasks Set Definition Tote Set Auto Zone Stacked Value 20 Switch ownership Tipping a Switch in your favor 1, +1/sec Scale Ownership Tipping a Scale in your favor 1 +1/sec Power cube in vault Placing a cube in your vault 5 Boost power up bonus Activating a boost 2/sec Parked on platform Successful climb Being parked on the Platform at the end of the round. Being suspended in air supported by the tower only 5 30 A Field Image Note that the Scale in between the two platform zones and the switches are on the outside of the zones 6

7 Total Score Strategy Development Game Analysis To find the most important tasks we visualize data with our Point-Analysis. Following are the scores from a theoretical perfect match (the maximum scores retrievable). Point-Analysis 7 Task

8 Strategy Development Final Tasks With our Point-Analysis we determined our strategy. Autonomous Modes Pass auto line and place a cube on the alliance's side of the switch Each of the 3 Positions on the field have multiple modes Teleop Tasks Individual tasks Retrieve & lift power cubes from the portal or the ground Place cubes into the exchange to gain powerups Place cubes on the scale and switches Climb the tower in the endgame Coopertition Climb with other teams Place cubes on the scale and switch Use the powerups levitate, force, and boost. 8

9 Strategy Development Practice Robot Our practice robot allows us to test ideas, make mistakes safely, prove mechanisms, hone fabrication techniques, evaluate software, and practice driving. We can do all of this before we build the competition robot and after the competition robot is sealed away for competition on Bag Day. 9

10 Strategy Development Approach To Design Team Prototyping Decisions Drivetrain Prototype Elevator Prototype Intake Prototype Hook Prototype Full Robot Prototype Our robot began in prototyping. To achieve our final robot, subteams formed, each testing out prototypes or systems which eventually developed into our final mechanisms and robot. Task Identification Team Prototyping Prototype Evaluation Focused Prototyping Robot Mechanism! 10 A summary of our prototyping process

11 Hardware Climber Needs Lift the robot 12 off the platform Consistency Wants Easy to use Speed Possible Ideas A-Frame hook deployment More pistons Less risky to wire Elevator hook Deployment Less weight If elevator malfunctions, we can't climb Final Climber Possibilities Polycarbonate 4 Bar Linkage Surgical tubing used to move 4-bar linkage Servo used to deploy Aluminum hook & Spring Spring used to move a removable bar attached to the hook Servo used to deploy Notables Servo used to deploy hook mechanism pro motors and a ratchet used to pull the robot up a string attached to the hook 11

12 Hardware Climber Climber Design Side view of the hook The Winch assembly Parts: Pro motor & 63:1 Versplanetary gearbox 2. Cones (keeps string in place) 3. ½" hex shaft couplers The Final Product 2 1 Note: The arm is uses magnetic force to keep the hook on the robot until the climber is used. 3 Parts 1. Aluminum hook 2. Polycarbonate latch plate 3. Deployment bracket 12

13 Hardware Intake Needs Stay inside the frame perimeter in the beginning of the match Get the power cube to the elevator intake Wants Intake from any angle/power cube configuration Deliver it to the elevator in under a second Possible Ideas Static Double Wheel Intake Per Side Power cube gets jammed between bumpers Fixed Position Dynamic Single Wheel Intake Adjusts to any power cube configuration Pivots to compress cube Flexible Intake Possibilities 1. Pistons to actuate outer intake and pull the power cube into the elevator 2. Surgical tubing attaches to the inside of the outer intake to adjust the intake to different power cube configurations Notables Passively adapts to Power Cubes Lift the cube without lifting the intake rollers 13 14

14 Hardware Intake Piston Actuated Flexible Intake Design Adjustable Outer Intake Intake wheels are tilted outward The adjustable outer Intake s aluminum arm Note: An intake on the elevator and an outer intake are used to guide and hold the power cubes The Final Product Our two adjustable intakes with compliant wheels gives us optimal intake capabilities. Parts 1. 10:1 gearbox & bag motor (1318 rpm) 2. Outer intake pistons 3. Intake retraction pistons 4. Arm 5. Arm holders 6. Intake wheels 14

15 Hardware Elevator Needs Lift consistently without errors Lift power cubes to the scale and switches Wants Quickly lift power cubes Hold power cube from any configuration Possible Ideas Cube Shooter Difficult to align Inconsistent 2 Stage Elevator Reliable/ simple Fast Final Carriage Possibilities 1. Compliant wheels and spatula to hold the power cube - Wheels wear out quickly - Difficult to fabricate accurately enough 2. Rubber rollers to hold power cubes - Can hold power cube from more positions - Similar intake to 2017 robot Notables Custom clutch stage for versaplanetary to keep 775 Pro Motor from burning out while keeping the carriage above the floor Utilizes limit switches for position control 15

16 Hardware Elevator Horizontal Roller Carriage Design Note: The top roller pivots to hold the power cube from any configuration The Carriage Moves the cube up and down the second stage of the elevator The Carriage Assembly Parts: 1. Horizontal Rollers 2. Bag motors & 10:1 Gear boxes 3. Upper Intake Pivot The Final Product 3 Parts Pro motors 2. Gearbox w/ encoder & clutch -Limit switches to tell when the elevator & carriage are at their bottom and tops 3. Rollers 16 1,2

17 Hardware Drive Train Needs Able to go over incline of the platform Reliability Wants Precision control Rigidity Possible Drive Train Ideas Mecanum Wheel Drive 6 Wheel Differential Maneuverable Fast Fast Complex Omnidirectional Simple Wheels not exposed from sides West Coast Drive Custom components required Lightweight with exposed wheels Lower traction Reliable movement Reliable movement Notables Can drive onto platforms Easy to mount onto Encoders enable precise movement and control 17

18 Hardware Drive Train 6-Wheel 5" Colson Differential Drive Train Design Simplicity was the idea which really drove our drive train, so we used Versaframe because it is easy to modify and assemble. We chose the 5 wheels because we want to be able to go over the slight incline of the platform. Another reason we modify the Versaframe kit for Colson wheels is because they have a lot of traction. The Final Product A Photo of Half of our Drive Train 4 A Half-AM14U3 Assembly CAD Model 3 5 1,2 Parts 1. 2 CIM Motors 2. Gearbox W/ Encoders 3. Belt Drive Colson wheels 5. Versaframe holes for mounting 18

19 Electronics & Pneumatics Electronics Notables 4 Autonomous switches Enables 16 different autonomous modes Ultrasonic sensor for autonomous Through beam sensor for intake Allows driver to see when power cubes are loaded and ready to go up the elevator Allows robot to detect power cubes during autonomous 4 Limit switches on the elevator Detachable E- chain wire routers for elevator and carriage 12 Talon SRXs and 2 Victor SPXs 2 Talons mounted on the first and second stages of the elevator 19

20 Electronics & Pneumatics Electronics board To be space efficient we have our electronics boards arranged on top of one another. Motor controller board This is located under the electronics board and above the power distribution panel. Uses CANbus interface. Pneumatic Notables 2 Single manifolds 2 Double solenoids 2 Different working pressures 4 Pistons, two connected to each manifold 20

21 Software Architecture Notables Macros PID feedback control Smart dash State machines Our team utilizes Eclipse and GitHub for robot coding and EDIT for scouting. Robot Sensors Drivers Software Actuators Mechanism A block diagram of our software architecture Macros Macros allow the drivers to repeat complex tasks easily by assigning functions to buttons on a controller which triggers a series of timed robot tasks. These use state machines to step through the function. 21

22 Software Architecture Proportional-Integral-Derivative (PID) Feedback Control Velocity PID control allows us to regulate the velocity of the drive train to deal with inaccurate movement. Positional PID control gives us the ability to move the elevator to a specific position and retain that position. Smart Dash Smart Dash receives information from the robot and displays selected data. This allows us to identify and/or solve problems more quickly. Chosen Programming Language The robot code is written in Java. Schematic for moving during autonomous mode 22

23 Scouting Network About Our scouting network allows us to collect large amounts of data on the abilities of other robots. We then use this data in making better game decisions. Programming Our scouting program was built using Python for managing the database and networking, and Java was used for the Android input UI. Order To keep the team from making conflicting alliance decisions we make use of various web-based Python tools such as Holoviews to clearly visualize data. The scouting data we look for during a match 23

24 Support Fall Training Before kickoff day students and mentors prepared for the build season ahead. Classes included fabrication, electronics, programming, and CAD. Game Parts To organize for the game without a field, we built the various game parts to properly practice. CAD We use CAD to design parts before fabrication and for digital preassembly of the robot. Offseason Projects We experimented with machine learning and created a Attendance Blockchain System which is now used throughout the school. 24

25 25