Everybot Build Guide

User Manual: Pdf

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Page Count: 49

The Robonauts Everybot, with a final budget of $1000, is an

affordable, robust, and simplistic robot that can be built with

nothing but basic tools and items found in either the kit of parts,

purchased from your local hardware store, or FRC retailer such

as AndyMark and VEXPro.

Table of Contents

●The Robot Can………………………………………………………………2

●The Robonauts Everybot Robot Will………………………………………..4

●The Everybot Chassis………………………………………………………..5

●Intake………………………………………………………………………...7

●Switch Scoring Arm………………………………………………………..13

●Bumpers…………………………………………………………………....29

●Everybot Photos…………………………………………………………....32

A 2018 Robot Can:

On the Sunday after the game reveal we created a list of everything we could think

of that a robot could do in FIRST Power UP. We tried to avoid putting things in the

robot can that have to do with robot design. Bolded are things that the Robonauts

Everybot does/attributes it has. Those that are underlined went into the robot will.

●Accurately navigate the field

●Track at Minute Maid

●Determine the switch/scale target

●Pick up a cube from the floor

●Receive cube from portal/exchange

●Be agile/fast

●Have a Low CoG

●Score in Switch

●Stand its ground

●Avoid Defense

●Put Cubes in Exchange

●Score on Scale at all Heights

●Provide visual aid to drivers

●Have a touch it own it intake

●Strafe

●Be light

●Drive onto the platform

●Drive over cable protectors

●Climb by itself

●Climb and get out of the way

●Assist another robot in climbing

●Assist another robot in climbing and also climb

●Assist 2 robots in climbing

●Assist 2 robots in climbing and also climb

●Place cube while moving

●Track cube (vision)

●Throw cubes

●Lift a cube

●Pick up cube from anywhere

●Cimb on other robots

●Drag dead robots

●Flip tipped over robots

●Flip ourselves

●Herd a cube

●Index off of a wall

●See vision targets

●Index off the exchange

●Grab cube in all orientations (13” and 11” side)

●Accept cube from another robot

●Give cubes to other robot

●Reorient cubes once inside the robot

The 2018 Robonauts Everybot Robot Will

Bolded capabilities in the robot can list were then put into the robot will. For

certain capabilities in the robot can we said we will not put resources into having

those capabilities but would be nice if they came for free.

●Deposit cubes in the exchange

●Place cubes on a switch

●Accept cubes from the portal

●Be able to be lifted by an alliance partner for climb points

●Cross the auto line in autonomous

To be more specific, the following is a basic breakdown of time allotment

for tasks in matches:

●Auton should dump a cube into the switch

●If Auton did not place the cube, place cube in your own switch, then

drive to the other end of the field. 15 seconds

●Cycle cubes from the portal to your opponent’s switch. Strive for 5

second cycle times. Empty out one portal (5-6 cubes).  25-30 seconds

●Drive back to your end of the field. 10 seconds

●Cycle cubes from your power cube pile to the exchange. Strive for 7

second cycle times. Score 9 cubes for all power ups. 63 seconds

●Total time: ~115 seconds (conservatively) Strive to complete these

tasks in any given match. We think this equals success.

This is a tight timeline of tasks… This accounts for one reason we decided

the floor intake did not need to feed into the switch scoring mechanism. We think

the cube you place in auton will either keep ownership of your switch for a large

portion of the match, or that you will not be able to outpace a robot playing this

same strategy against you. The other reason we decided to segregate the scoring

mechanisms was to be able to optimize each mechanism for its one task rather than

compromise each to achieve another task. Everybot should be simple and fast at

placing in the opponent’s switch and gaining power ups for its own alliance.

The Everybot Chassis

Chassis Type: We decided to use the AM14U3 chassis since it comes in the kit, is

a decent chassis, and with the 6 inch rubber treaded wheels that come with it allow

it to drive onto the platform with almost no issue (bumper scrapes a little).

Chassis Size: For the frame size we knew we did not want to build a wide robot as

wide robots are harder to maneuver around cluttered fields. We cut the frame to be

27.5” X 28.3” which is the square configuration of the AM14U3. We also cut the

front end plate to where there was a 6” long section at each corner on the front of

the robot to satisfy rule R23 that states that at least 6 inches of bumper must be

placed on each side of each outside corner.

Intake

We decided early on that a side-roller intake similar to the popular landfill

tote intakes from 2015’s Recycle Rush would be a good solution for picking up

power cubes. Everybot’s intake structure is made up of 1x1 1/16” wall aluminum

square tube that comes in the kit of parts. At the end of each of two pivoting arms,

we put BAG motors into 10:1 versaplanetary gearboxes driving AndyMark

compliant wheels.

There are four types of aluminum extrusion used on the intake:

●1” x 1” x 1/16” wall boxtube (16’ in the KoP also available at Home Depot)

○Qty(1) x 27.5”

○Qty(2) x 12.75”

●⅝” round aluminum (hard anodized igus rod in the KoP)

○Qty(4) x 3.1875”

○Qty(4) x 2.125”

●Churro shaft (left over from the AM14U KoP drivetrain)

○Qty(6) x 0.875”

●⅛” plate (left over from the cutout in the front of the AM14U frame)

○Qty(2) x ~2.7” x ~2.45”

To manufacture the boxtube parts one they are cut to size, measure out the

positions of the holes you’ll be drilling based on the drawings below:

Ladder bar (27.5” part):

(mirror on the other side of the boxtube)

Intake arms (12.75” parts):

(there are two of this part; be sure to check the CAD or other pictures to be sure

you drill each hole out to the right size)

All “small” holes are clearance holes for 10-32 bolts (#7 drill bit).

All “large” holes on the ladder bar are ⅝”, created using a step drill.

All “large” holes on the intake arms are ¾”, created using a step drill.

To ensure that the holes on each side of the tube line up with each other, first

drill all the way through the tube using the 10-32 clearance drill, then drill out the

applicable holes to ⅝” using the step drill.

When assembling the structure with the ⅝” aluminum rod standoffs, you can

estimate the center to drill and tap to 10-32 by hand. This operation could be done

on a lathe, but it will be close enough for this application. To ensure that the holes

line up, we drilled and tapped many of these standoffs in place while assembling.

They may be a tight fit into the holes you made with a step drill. You may need to

press in your custom standoffs using a vice.

To create the pivot points for the intake arms, press the Igus plain bearings

(in the Igus bag in the kit) into the ¾” holes you put in the intake arms. These

should make for a low-friction and sturdy joint.

The final part you need to fabricate is from the leftover ⅛” plate from the

front section of the AM14U chassis. Just cut a flat section from the C-channel and

measure measure out these dimensions. This is the yellow part in the pictures

above. The positions of the holes are the only critical dimensions, not the shape of

the part.

Roller assembly:

Build up two versaplanetary gearboxes with 10:1 reductions and BAG

motors. See the VEXPro product page for assembly instructions. Space out the

AndyMark compliant wheel such that they do not touch the box tubes using

schedule 40 ½” PVC spacers. We cut ours to about ¼” long. Cap the end of the

versaplanetary output shaft using a ¼”-20 bolt and large washer. Bolt each

versaplanetary gearbox to each of the intake arm boxtube parts. Be sure to use the

0.875” long churro pieces to keep from crushing the boxtube as you tighten the

10-32 bolts.

Tensioning configuration:

There are three sets of elastic. One, done with 5’ of latex tubing (in the kit)

pulls the arms out from a stowed position. The other two sets, made up of size 64

rubber bands (lots of them) are slack until the arms have folded out to the correct

width for intaking cubes. They stretch as cubes are sucked into the robot and

provide force between the rollers and the cube.

To start the match, the rollers are folded in towards each other and a zip tie

is put loosely around the BAG motors. This loop is attached to the arm so that

when it lifts, the intake flips outward, extending past the frame perimeter above the

bumpers.

We struggled with getting the intake wheels to grip cubes reliably. The black

AndyMark 4” compliant wheels were too stiff so we cut out some of the spokes so

they would compress more easily. To make them more grippy, we stretched latex

rubber bands around them. This worked well but they often fell off. We settled on

strips of gum rubber zip tied to the outside of the wheels. There’s a million ways to

increase the coefficient of friction between your wheels and the cube. You should

experiment with materials you have.

Switch Scoring Arm

When conceptualizing the scoring arm we knew we wanted to get cubes on

one side of the robot and score them on the other. This lead to an “over the head”

scoring arm. We looked into using the 775 Redline and the 4:1 57 Sport gearbox

along with a very large external reduction however we settled on a VexPro BAG

motor on a 100:1 VersaPlanetary gearbox with a 22:72 Chain reduction. The

following is a screenshot if the JVN Mechanical Design Calculator used to

determine what ratio would be appropriate.

This is the cut list for the scoring arm:

●1” x 1” x 1/16” wall boxtube (16’ in the KoP also available at Home Depot)

○Qty(2) x 33.875”

○Qty(2) x 41.5”

○Qty(2) x 24”

○Qty(2) x 15”

●¾” x ¾” Aluminum Angle (From Home Depot)

○Qty(1) x 22”

●¾” x 9/16” Aluminum C-Channel (From Home Depot)

○Qty(1) x 27.75”

●1-½” x 1-½” Aluminum Angle (From Home Depot)

○Qty(1) x 27.75”

○Qty(1) x 22”

●⅛” Thick Aluminum Plate (From Home Depot)

○Qty(2) @ 2” x 9”

●.300” Corrugated Polycarbonate (From Home Depot)

○Qty(2) @ 8.5” x 13”

○Qty(1) @ 7.5” x 32”

○Qty(1) @ 15” x 22”

○Qty(1) @ 12” x 22”

●3/16” Thick Plywood (From Home Depot)

○Qty(1) @ 20.25” x 10.125”

●½” VexPro Hex Shaft

○Qty(1) x 27.75”

●½” Schedule 40 PVC

○Qty(1) x 1.1”

○Qty(1) x .10”

○Qty(1) x 1.875

○Qty(1) x 1.175”

○Qty(1) x 1.19”

Once all the parts are cut to the sizes specified above the ⅛” thick plates should be

cut according to the drawings below. The large hole is a 1.125” bearing hole and

the smaller holes are .201” a number 10 clear hole.

The two 24” long 1”x1” box tubes need to be machined on one end according to

the following drawings. The small holes are #10 clears (.201”) and the large hole is

.75” to allow for a ½” hex shaft to fit through. I recommend drilling this hole with

a step drill.

These are the only parts that need to be machined before being assembled. The rest

will be clamped together and match drilled.

Arm Assembly

Most of the assembly on the arm was done by clamping parts into place and

then match drilling. For the most part this eliminated any part misalignment.

To begin the arm assembly we will put together the actual arm. To start we

need the two 24” long 1”x1” box tubes machined above along with the two 15”

long 1”x1” box tubes and two VexPro Versaframe 90 degree gussets. Everything

should be clamped together and match drilled. 5/32” rivets or 8-32 bolts can be

used to attach these components. The following drawing shows how the parts

should be clamped together. You will need to put two of these together.

Once both arm sides are assembled VexPro Versahubs and the 72 tooth plate

sprocket need to be attached to the arm. The left arm will be assembled according

to the following drawing. The holes on the 24” long arm should line up with the

holes on the VexPro components. Green is the 72 tooth plate sprocket, purple is the

1.125” ID bearing bore VersaHub, pink is the plastic ½” hex VersaHub, yellow is

the 24” long arm and blue is the ½” hex metal VersaHub. The holes in these Vex

components will need to be drilled out to a #10 clear (.210”) to allow the bolts we

are using to fit through them.

The right arm should be assembled to the following drawing which matches

the color scheme above.

After both sides of the arm are assembled the ¾” x ¾” angle (purple)can be

attached to both arm sides using rivets or bolts. All of the polycarbonate plates

were attached with VHB tape that is included in the kit. In the following drawing

the blue plate is the 8.5” x 13” polycarbonate sheet, there is one on each side of the

arm. The pink plate is the 22” x 15” polycarbonate plate. The brown plate is the

22” x 7.5” polycarbonate plate. The 22” long 1-½” x 1-½” angle gets mounted

below the brown polycarbonate plate using rivets or bolts.

Master Pivot A-Frame Assembly

Most of the master pivot A-frame is

match drilled. We placed the two 33.875”

1” x 1” box tubes in the two front corners of

the robot and attached them at the bottom

with 10-32 bolts to steel angle gussets from

Home Depot. The gussets are also attached

to the chassis using 10-32 bolts. During this

process it is best to have someone holding

the box tubes vertical until the rest of the a

frame is assembled to keep the angle

gussets from bending.

After the vertical box tubes

are installed the tie plates can be

clamped to either side of the 1x1s

at the top. They need to be match

drilled for a 10-32 bolt (.201”)

1.5” long bolts need to be used to

attach these components. If

desired you can mark them and

trim them to make them match the

box tubes. Once the tie plates are

installed the the two 41.5” 1” x 1”

box tubes can be installed to

support the vertical box tubes. Two 10-32 bolts should connect the box tube at the

top and at the bottom it should be attached to the frame using another steel angle

gusset. We also connected the two vertical box tubes with two timing belts (come

in the kit as a part of the kit chassis) that were cut to act as tension members. These

greatly strengthened the arm assembly.

Next the ⅛” master pivot

plates need to be installed, these

should be clamped to the box tubes

and then match drilled and bolted in

with 1.5” long 10-32 bolts. Below

these plates we mounted the 27.75”

long C-Channel with 10-32 bolts.

Next the ½” hex bearings can be placed into these bearing holes. The arm

can also be placed in with the PVC Spacers. The 1.175“ long spacer goes on the

left and the 1.19“ long spacer goes on the right when looking from the back of the

robot. The ½” hex shaft is then pressed in, you may need to loosen the bolts on the

Versahubs on the arm to get the shaft through all of them. Shaft collars then go on

each end of the shaft.

The last major thing to do for the arm is install the motor and the chain

tensioner. Assemble a VersaPlanetary with a 100:1 and a BAG motor. Bolt the

VersaFrame Corner Gusset in the location shown in the photo below with 10-32

button head bolts and then install the .10” long spacer closest to the motor followed

by the 22 tooth sprocket followed by the 1.1” spacer then use a large ¼-20 washer

and bolt to retain the spacers on the shaft.

The chain tensioner consists of a tie plate cut in half with one of the holes

drilled out to .86” A metric step drill is ideal for this, but it’s ok if the hole is a little

oversized. The other plate needs to have the hole directly across from the .86” hole

drilled out for a 10-32 (.201”) The following photos show how the tensioner is

mounted with 10-32 bolts.

For the length of the chain run we just put together pieces of chain until it

looked about right and then added a tensioner. There are better ways to do this such

as calculating the center-to-center distance for the shafts however the VexPro

Corner Gusset flexes making a chain tensioner necessary. Slide the assembled

tensioner under the chain along the box tube until the chain is tight and match drill

the holes for a 10-32 bolt, 1.5” long.

Bumpers

For the bumpers we made a single piece unibumper with wood that was 4.5”

tall due to the rule stating your bumper wood must be 5+/- ½”. The bumper wood

is ¾” thick as required. The bumper cut list is as follows

●1” x 1” Aluminum Angle .125” Thick (From Home Depot)

○Qty(2) x 4”

○Qty(2) x 2”

●¾” Thick Plywood

○Qty(2) @ 4.5” x 7.25”

○Qty(2) @ 4.5” x 28.75”

○Qty(1) @ 4.5” x 30”

We used these steel gussets in the corners and attached them with wood

screws. The two 4” long segments of angle mount the back of the bumper to the

robot and the 2” long segments of angle attach the front of the bumper to the robot.

Wood screws are used to attach the angle to the bumpers and then 10-32 bolts are

used to attach the angle to the robot. The following pictures show an example of

this.

Everybot Photos

Everybot Build Guide

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