Issaquah Robotics Society (IRS) Issaquah High School Washington FRC Team 1318

Transcription

1 Issaquah Robotics Society (IRS) Issaquah High School Washington FRC Team 1318 Engineering Notebook 2015 Season

2 Our Robot Toothless CAD Model Stabilizer Recycling Container Extractor Elevator Intake Drive Train 2

3 Table of Contents 1. Engineering Story 4 2. Our Product Cycle 5 3. The Game Summary 6 Actions & Points 7 4. Strategy Development Game Analysis 8 Autonomous/Teleop Strategy 9 Practice Robot 10 Approach To Design Hardware-Mechanisms Recycling Container Extractor 12 Intake 14 Elevator 16 Drive Train Electronics & Pneumatics Software Architecture Scouting Network Support Final Design Our Sponsors 27 3

4 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. 4

5 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. 5

6 The Game Summary RECYCLE RUSH is a recycling-themed game designed for the 2015 FIRST Robotics Competition (FRC). It is played by two Alliances of three Teams each. Alliances compete simultaneously to score points by stacking Totes on Scoring Platforms, capping those stacks with Recycling Containers, and properly disposing of Litter, represented by pool noodles, in designated locations. Each RECYCLE RUSH Match begins with a 15-second Autonomous Period in which Robots operate independently of their drivers. During this period, Robots attempt to move themselves, their Yellow Totes, and their Recycling Containers into the area between the scoring platforms, called the Auto Zone. Additional points are awarded if the Yellow Totes are arranged in a single stack. During the remaining 2 minutes and 15 seconds of the Match, called the Teleop Period, Robots are controlled remotely by student drivers located behind the walls at the ends of the Field. Teams on an Alliance work together to place as many Totes on their Scoring Platforms as possible. Alliances earn additional points for Recycling Containers placed on the scored Totes, with Recycling Containers at greater heights earning more points. Alliances also earn points for disposing of their Litter in either their Landfill Zone (the area next to the Step marked by the white line) or placing Litter in or on scored Recycling Containers. Alliances that leave unscored Litter marked in the other Alliance s color on their side of the Field at the end of the match add points to the score of the other Alliance, as it is considered unprocessed and not properly disposed. 6 The summary above was extracted from the 2015 FRC Game Manual

7 The Game Tasks & Points Autonomous Tasks Definition Value Robot Set Robots in Auto Zone 4 Tote Set 3 Yellow Totes in Auto Zone 6 Recycling Container Set 3 Recycling Containers in Auto Zone 8 Stacked Tote Set Tote Set in Auto Zone Stacked 20 Teleop Tasks Definition Value Scored Gray TOTE Fully Supported By Scoring Platform 2 per gray tote Scored RECYCLING CONTAINER Fully Supported By Gray Tote(s) 4 per container LITTER Scored in/on RECYCLING CONTAINER LITTER Scored in LANDFILL ZONE UNPROCESSED LITTER Bonus Own Side Totally Within Own Landfill Litter On Opposing Side BUT Not In Their Landfill COOPERTITION SET 4 Yellow Totes Fully Supported By Step 20 6 per container 1 per litter 4 per litter COOPERTITION STACK 4 Yellow Totes Stacked In 1 Column on Step 40 A Field Image Note that the scoring platforms are the white platforms. The step" is inbetween landfills. 7

8 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 Task Note: Though max stacks are worth the most points during a match, we consider making shorter stacks (of 4 totes and a recycling container) a reliable alternative. 8

9 Strategy Development Final Tasks With our Point-Analysis we determined our strategy. Autonomous Modes Secure step recycling containers onto our side and move robot into auto-zone Stack and move yellow totes and robot into autozone and release stack so the robot isn t in contact Teleop Tasks Stacking Retrieve & lift recycling container Load litter Intake tote from tote chute or landfill and stack under lifted recycling container Place stack on scoring platform Coopertition Bring own yellow totes to center (Lift other team s yellow totes) Complete (or begin) the coopertition stack 9

10 Strategy Development Practice Robot 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. 10 Our competition bot, Toothless, (left) and practice bot (right) before Bag Day

11 Strategy Development Approach To Design Team Prototyping Decisions Arm Prototype Intake Prototype Elevator Prototype Drivetrain Fabrication 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 Students in a brainstorm session guided by mentors Prototype Evaluation Focused Prototyping Robot Mechanism! 11 A summary of our prototyping process

12 Hardware Recycling Container Extractor Needs Retrieve recycling containers on step 6ft beyond landfill Retract into available robot space Possible Ideas Wants Retrieve two recycling containers simultaneously Fast positioning over the recycling containers Reel Sweeper Articulated Arm Tape-measure-like device which extends a hook into recycling containers (jams) A large L piece which sweeps recycling containers on step (unreliable, tall) Articulated Arm Possibilities An extending arm that folds up into available robot space (fastest option) 1. Direct-Pneumatic Joint - Angle too large for piston 2. Motor at Joint - Heavy, needs too much torque 3. 4-Bar Linkage - 2-actuators, precise placements required =Motor =Pneumatics Notables Our extractor can retrieve two recycling containers Can block some types of recycling container extractors 12

13 Hardware Recycling Container Extractor 4-Bar Linkage Articulated Arm Design 4-Bar linkage CAD derived from Lego prototype Lego Prototypes Retracting Teeth 4-Bar Linkage The arm retracted The arm extended The Final Product Parts 1. (4) Pistons 2. 4-Bar Linkage 3. Extension arms with retracting teeth 13 Note: two pistons are for the extension arms containing the retracting teeth and two are for the 4-bar linkage

14 Hardware Intake Needs Collect totes and recycling containers into our elevator Rotate recycling containers upright Wants Multi-function intake (one mechanism for both items) Flexible and easy to operate Possible Ideas Rigid Wheeled-Intake Gets jammed (inability to apply sufficient pressure onto totes to move it) Fixed position (cannot rotate recycling containers) Flexible Wheeled-Intake Adjusts to both totes and recycling containers (has passive pressure when collecting to grip) Arm pivots 75 degrees (vertical rotation) Flexible Intake Possibilities 1. L-Shaped Intake - Intakes both totes and recycling containers 2. Angled Intake - Conflicts with Elevator space-wise =Motor =Pneumatics Notables Passively adapts to totes and recycling containers Pivots (to re-orientate recycling containers top up) 14

15 Hardware Intake L-Shaped Flexible Intake Design L-Shaped Wheeled Intake The Flexible L- Shaped Intake Polycarbonate Arm The Pivoting Piston Note: two intakes are used to clasp totes and recycling containers The Final Product 1 4 Our two L-shaped wheeled intakes with angled motors for optimal intake capabilities. 3 2 Parts 1. 35:1 motor/gearbox 2. Piston 3. Arm 4. Intake wheels 15

16 Hardware Elevator Needs Lift recycling containers so that totes can go under it Lift and stack totes under recycling container Wants One mechanism to stack both items Fast and compact (doesn t disrupt intake space) Possible Ideas 2-Arm Lifter 2 4-bar linkages which grip game items from both sides Doesn t stack efficiently Carriage Lifts recycling container so that a tote can go under it Bottom-up stacking Carriage Possibilities 1. Pneumatic-Driven Elevator - Limited amount of compressed air 2. Motor-Driven Chain Elevator - Reliable, lifts both recycling containers and totes =Motor Notables Stacks from the bottom-up (efficient and simple) Utilizes encoders for position control =Pneumatics 16

17 Hardware Elevator Motor-Driven Carriage Elevator Design The Carriage Attaches to both totes and recycling containers with flexible, hinged tabs. The Support Structure The structure which the carriage moves vertically on. Note the spring-loaded metal tabs adapt to totes and recycling containers The Final Product 1,2 3 5 Parts 1. (2) CIM motors 2. Gearbox w/ Encoder -Encoder enables a PID feedback loop 3. Chains 4. Carriage 5. Support frame 17 4

18 Hardware Drive Train Needs Stability Reliability Wants Precision control Easy to control Possible Ideas Mecanum Drive 6 Wheel Differential Maneuverable Fast Fast Complex Simple Simple Omnidirectional Heavy Wheels not exposed from sides Large West Coast Drive Lightweight with exposed wheels Custom components required Lower traction Reliable movement Reliable movement Notables Can drive onto/over scoring platforms and litter Space for electronics board Encoders enable precise movement and control 18

19 Hardware Drive Train 6-Wheel Differential Drive Train Design Simplicity was the idea which really drove our drive train, or moving reliably without complication. We chose the 6-wheel differential drive for this because it was so reliable. The back wheels were adjusted so our robot could lean on them. The Final Product A Photo of Our Drive Train 4 3 1,2 5 Parts 1. (4) CIM Motors 2. Gearboxes W/ Encoders 3. (2) Belts 4. (6) Wheels 5. (2) Frames 19 A Half-AM14U2 Assembly CAD Model

20 Electronics & Pneumatics Electronics Notables Autonomous switches Switch to change autonomous mode Through beam sensor & indicator light Allows drivers to see if totes are loaded with indicator light Allows robot to detect totes during autonomous Limit switches Detachable D-Link router Infrared distance sensors 20

21 Electronics & Pneumatics Top electronics board To be space efficient we have our electronics boards arranged on top of one another. Bottom electronics board This is located near to the drive train and top electronics board. Pneumatic Notables Manifold Solenoids are organized into a smaller space Digital pressure sensor 21

22 Software Architecture Notables Macros PID feedback control Smart dash State machines Our team utilizes Eclipse and GitHub for robot coding and Visual Studio for scouting. Robot Drivers Software Sensors Actuators Controllers Components 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. 22

23 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 is programmed in Java. Ideas from a programming brainstorm on our autonomous mode 23

24 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 Visual Studio Web 2012 through C#, HTML5, JavaScript and CSS3. A priority was making the UI easy to use for scouting. Order To keep the team from making conflicting alliance decisions we make use of Tableau Desktop to clearly visualize data. The scouting data we look for during a match 24

25 Support Fall Pre-Season 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. Robot In A Box The Robot In A Box and Pneumatics In A Box simulate the robot for testing, allowing us to avoid damage or test without the robot. The Robot In A Box Pneumatics In A Box 25

26 Final Design Our competition robot, Toothless (from How To Train Your Dragon ), was assembled in just a few days due to experience gained with building our practice robot. These pictures show the configuration at the start of competition season, but the design evolved throughout competition season to improve performance (see next page for details/picture) 26

27 Notables - Our Engineering Story (P.4): Our commitment to embodying FIRST using an effective and efficient engineering process - Game Analysis (P.8): Data visualization to identify the most important tasks - Container Extractor (P.12): A 4-bar linkage that extends out and grabs two recycling containers from the center step - Wheeled Intakes (P.14): Pivoting arms able to orient recycling containers and intake both totes and recycling containers - Elevator (P.16): A carriage with arms containing lifting tabs provided the ability to rapidly lift totes and recycling containers. During competition season the tabs were changed from flexible polycarbonate to spring-loaded, hinged aluminum for improved reliability. - Stabilizer (No dedicated page): Two polycarbonate ears at the top of Toothless designed to keep containers from falling sideways. During competition season we realized the ears couldn t accommodate higher stacks. Because of this, we changed the design so pneumatics actuate taller stabilizers to grasp recycling containers for higher stacks. 27 Toothless after modifications made during competition season

28 Our Sponsors MR/MRS WENZEL MR/MRS TICKMAN WATTS FAMILY 28 MATCHING FUNDS PROVIDED BY: MICROSOFT & THE BOEING COMPANY