2020:Wheel of Fortune
Team Lead: Alex L.
Prototyping 1/5/2020-1/11/2020
Overview: Based on initial team brainstorming and sketching, as well as the information from Strategy Subteam, we determined to prototype:
- A wheel(s) and a form of vision used to spin the control panel from the side.
Observations: We observed the following over the course of prototyping:
- Color sensor has limited range (3.8125 [3 and 13/16] in. maximum when parallel to surface)
- Unless the color sensor is placed at the frame perimeter (results in wheel being further back), it must be actuated
- Wheel has a fair amount of kick-back, must be firmly and strongly mounted
- Wheel is still spun at an adequate speed despite loss in efficiency from gearbox
- An L-shaped arm going over the wheel is impossible due to its weight
- Color sensor should be used for Rotation Control (simply relying on encoder is too unreliable)
Decisions:
- Wheel will be mounted parallel to the ground
- Middle of wheels must be 2 ft. 8 1/8 in. from the ground (Top of frame will be 28.25 in. from the ground)
- Color sensor will be used for vision
- Two 4 in. compliance wheels (blue)
- Neo 550 Motor for wheel
49:1 Gear ratio (provides WoF with a speed of ~51 RPM)- 16:1 (Two 4:1 ) gear box
Sensor must be actuated to keep wheel at frame perimeter- The wheel will be facing up with the motor facing down
Color sensor will be actuated over the compiance wheelA smaller gear ratio in the gearbox may be used with an encoder to reduce weight and kickback- Color sensor will be mounted at the frame perimeter (eliminates need to actuate)
Need to do:
- Assemble final mechanism
- Finish code
Design
- 1/11/20
Attendance: Alex L2, Owen P, Ishan R
The subteam formed. We started developing concepts and ideas for how to spin the control panel. Through calculations with RPM, wheel circumfrence, and real-estate on the robot it was decided to go with two 4 in. blue compliance wheels and a 550 motor with a 49:1 gear ratio to spin the panel. It is known that we will use the color sensor but not how or where we will mount it.
- 1/12/20
Attendance: Alex L2, Owen P, Ishan R
Assembled prototype of wheels on the 550 motor with a 49:1 gearbox. Experimented with different distances and angles with the color sensor and decided that the sensor will be actuated to fit with the current placement of the wheel (edge of wheel near edge of frame perimeter). Brainstormed various ways to mount motor and sensor to framing. Tested prototype on the plywood control paned and found that the wheel spins at the needed speed (>45 RPM) and makes adequate contact.
-1/14/20
Attendance: Alex L2, Owen P, Ishan R
Set deadlines for design (see 2020 Intergration). The wheel mechanism was weighed at 1.9 lb and an estimate of 3-3.5 lb for the entire system was made. A few parts were CADed (servo mounts) and the .h file is nearly complete.
-1/16/20
Attendance: Alex L2, Owen P
Continued experimentation, design, and CAD. Decided that the servo and sensor must be mounted to the side of the wheel since mounting over the wheel requires an arm that is too heavy. More measurements and calculations were made about the height of the frame and another possible gear ratio.
-1/18/20
Attendance: Alex L2
Redid JVN calculator for mechanism. Found that Neo 550s were overkill and that a 49:1 gear ratio is still optimal. CAD assemblies were started for various parts of the mechanism (spinner and frame) and framework is nearly complete.
-1/19/20
Attendance: Alex L2
Switched to Neo 550s (for hopefully the last time) due to their integrated encoder and lighter weight for a small increase in price. Continued CAD work, but found interferences with battery box and climber winch so design may need to be redesigned or redone.
-1/21/20
Attendance: Alex L2, Owen P, Liam T
CADed brackets to mount the frame to the top of the c-channel of the drive base. Continued with CAD, design, and programming for mechanism.
-1/22/20
Attendance: Alex L2
Continued CAD work and design.
-1/23/20
Attendance: Alex L2
Extended framing to mount to the L-bracket of the drive base. Started design and CAD for color sensor.
-1/25/20
Attendance: Alex L2, Owen P
Desided to mount servo and use a linkage to connect an arm to the servo horn. The arm will be mounted on the same axle as the spinner. Experimented with various linkage lengths and hole possitions.
-1/26/20
Attendance: Alex L2
Changed design to mount the color sensor at the frame perimeter instead of the wheel edge and use a static mount. Want to add in a spring on the motor mounting for shock absorption. CADed brackets for sensor mounting and need to determine how the spring will mount to the motor and how they will mount to the frame.
-1/28/20
Attendance: Alex L2, Owen P, Ishan R, Liam T, Nikko S
Design was redone and no longer has a spring. CAD was redone for various parts (mainly brackets) and new mechanism is designed. Color sensor code is well on its way and work will continue to finish it.
-1/29/20
Attendance: Alex L2, Nikko S
Finished CAD for mechanism (only small changes an variations are left) and got a new weight (see Robot Design). Drawings have been made and fabrication has nearly begun.
-1/30/20
Attendance: Alex L2, Owen P, Ishan R, Liam T
Fabrication has begun (motor mounting bracket was started and the 3D printed shaft was finished). Programming has continued testing with the prototype and good progress was made.
-2/1/20
Attendance: Alex L2, Owen P, Ishan R
Fabrication has continued (motor mount and color sensor arm were finished) and programming conducted futher testing with the prototype on the wooden WoF.
-2/2/20
Attendace: Alex L2, ???
Still waiting on the Harris bracket but otherwise prepared to begin assembly.
-2/4/20
Attendance: Alex L2, Owen P, ???
Continued programming.
-2/5/20
Attendance: Alex L2, ???
Continued programming.
-2/6/20
Attendance: Alex L2, Owen P, ???
Continued programming.
-2/8/20
Attendance: Alex L2, Owen P, Ishan R
Began assembly (waitning on gearbox stuff to arrive) and for the most part finished WoF code.
-2/9/20
Attendance: Alex L2, Owen P
Finished assesmbly and mounted to robot.
