2011:Electrical Main: Difference between revisions
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#<strike>Arm unfold/extend </strike>This is unnecessary, unfolding is a mechanical function ONLY | #<strike>Arm unfold/extend </strike>This is unnecessary, unfolding is a mechanical function ONLY | ||
#Gripper rollers | #Gripper rollers | ||
#Minibot deployment release | #Minibot deployment release | ||
#Signal lights | |||
<br> | <br> | ||
'''INPUTS''' | '''INPUTS''' | ||
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#Drivetrain motors speed and direction | #Drivetrain motors speed and direction | ||
#Arm angle | #Arm angle | ||
#Line tracking sensors | #Line tracking sensors | ||
#Arm limit switches (opto) | |||
#Gripper "got-it" sensor (opto) | |||
<br>'''ARM PLACEMENT ACCURACY''' Need to determine the required resolution (accuracy) of the arm angular sensor. | <br>'''ARM PLACEMENT ACCURACY''' Need to determine the required resolution (accuracy) of the arm angular sensor. | ||
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''edit: Generally, the SW team usually throws away the bottom two bits of ADC readings as it's likely noise'' | ''edit: Generally, the SW team usually throws away the bottom two bits of ADC readings as it's likely noise'' | ||
<br> | <br> | ||
= Robot Sensor Requirements<br> = | = Robot Sensor Requirements<br> = |
Revision as of 07:00, 29 January 2011
Electrical Subteam Members
- Students
Alex Rozanov
Vaughn Thompson
Matthieu Dora
Henry Wagner
- Mentors
Dave Burlone
Dean Smith
Christian Stoeckl
Dave Schoepe
Tentative Attendance Calendar
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Master Task List
High Priority
- Determine mounting spots for the battery
- Create fixture for mounting the battery
- Design (in a modeling program) a new control board layout to fit all electronics
Test brightness of LED tape when mounted on a pipe. (Completed 1/22)
Medium Priority
Put cables on new batteries (See Subtasks)Complete- Test batteries with power meter and record electronic results on wiki (See Subtasks)
- Design signal lights ("want-it"/"got-it")
Choose encoder for Arm Axle2011_EncodersComplete 1/23Design photoelectric sensor (similar to Banner offerings)Completed 1/23- Work with programming on line sensors calibrating, adjusting etc. (See Subtasks!)
- Construct/prototype photoelectric sensor
- Re-Crimp Ethernet cables for use at Rally and competitions
- make a listing of the motors we are using along with run current, stall current, circuit breaker size, and wire guage.
Low Priority
- Prep gyro - needs set of pins soldered to the board
- Crimp PWM ends to flying leads of Drivetrain wheel encoders
Sub Task List
Control Board In Inventor
The current drive train design is almost complete in Inventor this means that we can start drawing in the control board.
- Must have at least three different designs to be flexible with mechanical group
- Must evaluate positives and negatives of any structural elements used to mount electronics
- Do a force test of the new corrugated plastic alongside a similar piece of polycarbonate.
- Measure the deflection and record the findings on the wiki to indicate if this is an upgrade or downgrade and by what percentage
- Place weight calculations on the wiki
- Think about cable routing and cable management.
- Think about how hard/easy it is to work on at competition, and visibility of LED's for troubleshooting (cRio, Jaguars, spikes).
- Should mount speed controller in an accessible spot (like on 2010/2009) robots
- Work on centering battery
Check all Batteries:
The batteries should have the tape removed and crimps checked and redone if needed.(Completed 1/18)Terminate tester with the appropriate leads(Completed 1/23)- Test Batteries with tester, plot and save results electronically on the wiki (should be ongoing)
Experiment with Line Sensors:
- Pull out a power supply and scope, find out how the sensors work, and test range and sensitivity.
Mock up on Thunderfoot for initial testing(Completed 1/15)- Test under different lighting conditions but on same surface
Test orientation of sensor (in 90 degree increments)(Completed 1/22) - Makes little to no difference
Measure Mach 1511 Polycarb
This is the thickness of the polycarb to use on the control board and order a sheet.
CAN Bus Minutia
- Make two Serial to CAN converters
- Make two CAN terminators
- Make four CAN cables
Safety Light: Wire up the Orange Safety Light - Complete 1/15
Communication Signals
Plan and design human player communication lights.Want-It Light(s)Got-It LightNeed to test visibility(Completed 1/22 - we will use 2 wraps of LED lighting)Pick materials- Choose mounting spot
- Construct
Motors: Inventory and test motors. - Complete 1/13
Links to Other Subteams' Important Stuff
Robot Electromechanical Design Features
OUTPUTS
- Drivetrain motors
- Arm elevation motor
Arm unfold/extendThis is unnecessary, unfolding is a mechanical function ONLY- Gripper rollers
- Minibot deployment release
- Signal lights
INPUTS
- Gyro
- Drivetrain motors speed and direction
- Arm angle
- Line tracking sensors
- Arm limit switches (opto)
- Gripper "got-it" sensor (opto)
ARM PLACEMENT ACCURACY Need to determine the required resolution (accuracy) of the arm angular sensor.
This is a very, very rough determintaion, based on some assumptions (because I didn't have the robot & arm dimensions). -Dave S
- Placement accuracy required:
- ubertube central hole is 12"
- scoring peg foot is 2.75"
- If perfectly centered, this leaves approx 4.5" gap between tube and scoring peg.
- Let's cut this in half to have some safety margin, and say we need to place the tube within 2" during autonomous mode.
- Sensor resolution required:
- Fully extended arm reaches to 9.5' (114")
- ASSUME that arm is pivoted at a point 48" above ground in the center of the robot, then the arm's length is about 68".
- the circumference of the arc the arm traces is 427"
- so 2"/427" times 360 degrees for a full circle gives about 1.7 degrees as corresponding to 2" in arm rotation out at the gripper.
- To allow for some margin of error, let's say we need to sense the arm angle at least within 1.0 degree.
So need to choose a sensor with 1 degree of angular resolution or better.
- IF use an analog sensor, cRio 9201 module is 12-bit ADC for a full scale input range of -10V to +10V. We would likely use less than its full range so we would not get its maximum resolution - the reference voltage for the ADC is internal and not user selectable.
edit: Generally, the SW team usually throws away the bottom two bits of ADC readings as it's likely noise
Robot Sensor Requirements
Drivetrain Sensors
- US Digital E4P Rotary Encoder (2) - Directly coupled to gearboxes
- Rockwell line following sensor (3+) -
Mounted as close to center as possible - Three in a line at the front of the bot, 1 inch off the floor (to the lens) center one fixed and the others adjustable from adjacent to 1 inch away.
- Gyro (KOP)
Arm Sensors
- Some Calculations (Arm Placement Accuracy) show that we need
1-2 degree tolerance0.5 degree minimum accuracy on the sensor. If using a potentiometer we should fine 1% tolerance pots- If using encoders must use both A & B phase for maximum accuracy
- Optical switches at extremes - Mounted as a flags (2) on the 12" sprocket
- Home Position Sensor
- Will be an optical sensor (OPTEK OPB815L)
- In the parked position the sensor will output 1
- Once the arm leaves the parked position the sensor will read 0
- When it leaves the parked position, this indicates "sensor home". This is the SW absolute point.
- 2 encoders for redundancy
- We decided to go with the E4P sensor instead of the E7P
- The E4P would be able to get up to .5 of a degree of arm rotation accuracy which is above our goal
- Worked with mechanical to determine that we will mount the encoders at the intermediate drive shaft of the arm.
The E7P would be able to get .25 degrees of rotation, but is twice as expensive
Manipulator
- Needs at least 1 "Got It" Sensor (maybe 2?)
- Would be nice to make this sensor active low
- We should impose the mechanical team to design a mechanical stop
- Will drive the "Got It" Light
Motor Outputs
General Assumption: CAN Based Motor Controls
Drivetrain
- 2 x Jaguar - CIM
Arm
- 1 x Jaguar - CIM?
Manipulator
- 2 x Jaguar - Continuous Rotation Servo
Visual Feed Back
Want-It-Indicator
- Used to relay to the human player what type of tube needs to be fed to the robot
- Needs to be viewable from all angles
- No breakables for this
Got-It-Indicator
- Used to tell the robot drive team that the robot is in "good" possession of a tube
- Needs to be viewable from all angles
- Needs to be viewable from far distances
- No breakables for this
Electrical Main Subteam's Engineering Notebook
Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
Engineering Notebook Templates Available at: Engineering_Notebook_Template
Please Label All Notebook Pages 2011:Electrical Main MM.DD to avoid confusion.
Component Specifications
2009 KOP Motors Spreadsheet (Chief Delphi)
File:Natl Instruments 9201 AnalogModule.pdf
Bill of Materials (Electrical)
Archives