robot hardware and design workshop (2013)robot hardware and design workshop (2013) [compatibility...

BISON

Robot Design Workshop:VEX Hardware

& Robot Building Basics

Nikolas KukertBison BEST Robotics

1Copyright © 2010 BEST Robotics, Inc. All rights reserved.

BISONBasics� Only use parts supplied in the consumable and

returnable kits (or approved optional items)� Robots containing additional parts will be disqualified

� Do not modify returnable parts� No paint, tape, etc. may be placed on these parts (except

painter’s tape on wi-fi keys and cable connectors)

� Robot must fit into a two-foot cube (initially) and weigh less than 24 pounds� Robot components may extend outside two-foot cube

after game starts

� All machines will be inspected for compliance prior to competing

Copyright © 2010 BEST Robotics, Inc. All rights reserved. 2

BISON

Servos

Controller

Analog

Motors/Servos

Battery

Digitali/o

WiFi key USB/TetherSerial

Joystick

(2)

ServoMount H/W

Servo Horns

Returnable Kit Items


(2)(2)

Servo Extensions

(2)

USB A-A cable

(16)

AAA Battery Charger

(4)

BISON

(2)

(2)

(2)

Motors

Drive Components


MotorController (4)

Screw TerminalMotor i/f Cable (4)

Screw TerminalSensor i/f Cable (8)

7.2V Battery

7.2V Battery Charger

Battery Adapter

(2)

Returnable Kit Items

BISONExample Hookup

Servo

Motor Controller

DC Motors

Battery

Motor Screw Terminal

Cortex Controller


BISONVEXnet Control System

• VEX Cortex Microcontroller• Dual ARM Cortex CPUs• Programmable• WiFi Radio Technology


BISON

VEXnet Cortex M3 Controller

System StatusIndicators

WiFi 802.11Proprietrary Comm8 Analog

inputs

12 DigitalInputs or Outputs

10 Motor/Servo Ports(Built-In ESC on 2 ports)

Standard SerialInterfaces

(UART, I2C)

SpeakerOutput


BISONVEXnet Joystick

2 XY Analog Joysticks

8 Buttons on Top

Plug-in USB/ WiFi Key

4 Buttons on Front-Side

Programming Interface

“Playstation” Game-Style Controller

3 Axis Accelerometer(XY Tilt, XYZ Accel, Shake)

Power Switch6 AAA

RechargeableBatteries


BISONVEX Cortex ConnectorsUSB

AnalogIn

DigitalIn/Out

2-wire motor

Standard SerialInterfaces

(UART, I2C)

SpeakerOut

1

12

1

8

SP

12

910 2-wire motor

3-wire PWMServo/Motor Ctrl

Gnd(Blk)

+5v(Red)

Sig(Wht)

Sig(Wht)

+5v(Red)

Gnd(Blk)


BISONDC Motors

� Four motors are supplied in the kit� Two large motors and two

small motors� Motors can be used to

power wheels, lifting arms or mechanisms, grippers, etc.

� Motor mounting brackets and screws are supplied in the Consumable Kit


BISONMotor Mounting Brackets� Use of motor mounting brackets to mount the motors

is no longer required.� However, they are HIGHLY recommended!� if they are not used when face mounting the motors,

it is easy to damage the internal gear plate.


BISONDC Motors

� Four External Motor Controllers supplied in the Returnable Kit (these MUST be used)�Connect via 3-wire external motor controller and

2-wire screw terminal cable (red/black) � Use motor ports 2 thru 9 only!

� Do NOT Use the Built-In Motor Controllers� Motor ports 1 and 10� Motor amperage may damage circuitry


BISON

DC Motors

� Servo/Motor Ports are Divided into 2 Banks� Bank 1 = Ports 1 - 5 � Bank 2 = Ports 6 – 10� Use only ports 2 – 9 � Each bank can support a maximum of 4 amps of current � BEST large motor stall current can reach 3.5 amps

� For Power Reasons, Spread Motors among Ports� No more than 2 motors plugged into ports 2 – 5 � No more than 2 motors plugged into ports 6 – 9� Otherwise you risk overcurrent and shutdown of the processor

� Sheet Metal Shield around the Large Motors IS Needed and Should NOT be Removed


BISONDC Motors� Connect wires to motor terminals

� Quick-disconnect terminals (Strongly Preferred!)� Solder

� Polarity is NOT marked on motors: positive (+), negative (-)

� Wiring (and programming) will determine clockwise or counter -clockwise rotation for positive stick movement

� Recommended to mount motors using supplied brackets and 8-32 machine screws Machine screws

must be cut toproper length to

avoid motor damage(use screws supplied in kit)!

Max screw depth=~1/8” (small motor)~1/4” (large motor)


BISON

3-Wire Motor Connection

External MotorController Standard 2-wire

Motor Cable

Standard 3-wirePWM connector

Suggest using painter’s tape or heat shrink tubing here

Screw Terminals for attaching motor leads


BISON

3-Wire Motor Connection

� Connectors are not keyed� Connect red to red, black to black


BISONServos� Servos produce a

specified rotational movement when activated

� Possible Uses� Activation of micro-

switches� Operation of grabber

mechanisms� Release of a spring-

loaded latch


BISONServos� Futaba S3003 or S3004 Series� Maximum 120 degree rotation (+60, -60)� Connection to Cortex Controller

� Via 3-wire Servo Power Adapter cable� Prevents damage to servos

� Use motor ports 2 thru 9 only

�Servo Horns may be modified

Servo Horns

(2) (2)

(1)


Do not overtighten mounting screws!

BISON

Motor/Servo Connectors� Placement of Servo Connectors

� VEX motor controller can be placed adjacent to a Futaba servo or extension connector

1) Keyed differently; will work but a tighter fit.2) Recommend keeping motor controller in a higher numbered

port; may lose one servo port due to this.

� Futaba servo & extension connectors ARE keyed BUT they will still fit in backwards. Pay attention to the keying and wire orientation (white wire to the inside).


1 2

BISONElectrical Connections� No-residue “painter’s” tape may be used to

secure VEXnet key and cable-to-cable connectors.

� Painter’s tape included in the Consumable Kit


BISON

Re-Syncing (Pairing) VEXnet


If VEXnet does not connect, you may need to re-sync thejoystick/controller pair by simplyconnecting a USB cable and powering on both units.

BISONLED Status Lights


Joystick Battery Status

Robot Battery Status

Communication Link Status

Game Status (not used by BEST)

• Green Battery – good charge• Yellow Battery - dying• Red Battery – dead

• Green VEXnet – communication established• Yellow VEXnet – searching• Lights on the controller and the joystick are

the same

BISON

BEST Programming Options

� Three different programming environments available� easyCv4 http://www.intelitekdownloads.com/easyCV4� RobotC http://www.robotc.net/download/cortex� Mathworks MATLAB/SIMULINK http://www.mathworks.com

� easyC is a block programming environment (similar to software for Lego Mindstorms)

� RobotC programs in C with a text editor, but it has runtime debugging (can step through program line by line and see what the results are)

� SIMULINK is graphical programming/modeling environment with simulation capability (see what your program will do before you download it to the Cortex)


BISON

� Direct USB Download

Downloading a Program

Uses only the A-A USB cable.

Battery is notneeded


BISONKit Changes for 2013� 1/8“ Hardboard was replaced by 1/2“ Plywood

� Minor changes made to hardware and miscellaneous items


OldNew

BISONKit Issues


� To prevent breaking the gears in the small motor, do not exceed kinetic energy load levels of 16 in2.lb/sec2.

� Higher levels of load/energy can be driven, but unless you are careful (slow and gentle) when reversing directions, the gears will be broken (and your team will be expected to pay for the motor).

BISONKit Issues� Secure cables/wiring to prevent stress at the

connections


BISONPowerPole Connectors


connect/disconnect here

leave connected here

BISONTeam Tips� Use quick-disconnect terminals to attach wires to motor

terminals (preferred). If using solder, tin motor wires before attaching to screw terminals since frayed stranded wires can cause a short.

� Do NOT solder wires to Cortex connectors!� Sensor cables, servo wires, and servo extensions are all keyed

in correct orientation; insert and remove carefully to avoid destroying connectors (pin connectors are very delicate).

� Tighten screws on motor and sensor connector cables so that wires are not loose and do not pull out.

� Mount Cortex to robot using #8 screws through holes provided; be careful not to over tighten.

� Avoid “hot insertion” of USB Keys.� You may operate tethered by removing the USB WiFi key and

connecting a USB A-A cable between joystick and Cortex.


BISONJoystick Calibration� If the motors hum or creep (sticks not returning to zero), the

joystick may need to be recalibrated� Calibration procedure (as extracted from the easyC help file):

1) The Joystick must be "Linked" to the Cortex Microcontroller using the VEXnet Keys.2) Hold the "6U" Back Switch depressed.3) While the "6U" Back Switch is depressed, use a small Allen Wrench (1/16" or smaller) or similar small straight tool

to depress and hold the CONFIG Switch.4) Hold both Switches depressed until you see the Joystick LED Flash RED and GREEN - you can now release both

Switches.a. There is a 10 second time limit to complete the following steps 5 and 6.

5) Now move both Joystick Pots to the maximum position desired in all 4 directions - Up, Back, Left, and Right.a. If a movement is not detected in all 4 directions, a timeout will occur after about 10 seconds and the Cal Mode

will be discontinued and the VEXnet LED will briefly Flash Red.b. The Joystick LED will continue to Flash RED and GREEN during the calibration process.

6) After movement is detected in all 4 directions, the Joystick LED will be ON and Solid GREEN.a. To "Save" the Calibration, depress and release the "8U" Top Switch Button.b. If the calibration is accepted and Saved, the Joystick LED will start Flashing Fast GREEN for a few seconds.c. If the Calibration is not Saved, a timeout will occur after about 10 seconds and the Cal Mode will be

discontinued and the VEXnet LED will briefly Flash Red.d. To cancel a calibration, depress and release the "7U" Top Switch Button. The Cal Mode will be discontinued

and the VEXnet LED will briefly Flash Red.e. If the Cal Mode is discontinued or saved, the Joystick LEDs will resume their normal function after the VEXnet

LED briefly Flashes.


BISONWheel Attachments

� Some proven techniques for mounting drive wheels to motor spindle.

� Other techniques can be used.


BISONLifting Mechanisms


Many mechanism designs can be created to lift or retrieve objects.

Belt and Pulley

Slide and Rail System Scissors Lift Parallel Arm Linkage

BISONLinear Drive Mechanism


Rotational motion of motor can be used to create a linear drive using belts and pulleys.

BISONGrabbing Mechanisms


Simple grabbing mechanism can be operated by a servo, allowing motors to

be used for lifting mechanisms.

Servo with Servo Horn

Wires attach armsto Servo Horn

As Servo rotates, grabber arms open and close

Pivot

BISONReminders

� Read Generic Kit Notes� Read Generic Game Rules� Read Game-Specific Rules� Re-read all of the above!� READ Q&A!


BISON

Where to find help?� Online documentation (BRI Site)

� http://www.bestinc.org

� BEST Public Message Board (for anyone)� http://tech.groups.yahoo.com/group/bestinc/� Must register for login account� Share ideas, resolve issues, …

� Official Q&A “Control System” Category� http://www.bestinc.org/cgi-bin/bestqna� Use “Official Q&A” page during contest for “rules specific” questions� Is this legal?

� VEX Forum� http://www.vexforum.com/forum.php� Technical questions about VEX equipment� easyC and RobotC dedicated forums included here

� Robotevents BEST Forum� http://forum.robotevents.com/forumdisplay.php?f=51� Dedicated user forum for BEST Robotics� Must register for a login account


robot hardware and design workshop (2013)robot hardware and design workshop (2013) [compatibility...

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