[4334] Research Project
 

This is a pre-season project for team 4334, the Alberta Tech Alliance. Today we are learning about some of the part choices we have to make when building a robot. The students have been divided into groups and will each be researching one of the following topics:

• Speed controllers
• Chain vs Belt
• Gearboxes
• Structural Materials
• Wheels

Each group will break discover the main parts (or classes of parts) that are used in their application. Then they will fill out as much of the following information as possible for each:

Title:
Picture:
Description:
Advantages:
Disadvantages:

After reviewing each of the options they will finish their evaluation with an evaluation of which solution they would recommend and why (or solutions if multiple are very close).
Once all of the submissions are up, I would love if the Delphi community would come in and comment, critique, and suggest additions to what our students have suggested in each area.
So without further ado, let’s get started!

I’d also like to wish everyone a happy 11/14 :),
- Alex

Re: [4334] Research Project
 

I’ll start us off with an example:
The topic I will cover is main controller:
There are three possible ways of filling this need:

• cRIO
• Arduino with Robot Open shield
• Vexnet Controller


Now let’s go into detail on each:
Title: cRIO
Picture:

Description: This is a robot controller that executes programs and handles input and output, providing the control center for the robot. This controller was developed by National Instruments and is provided to all teams in the kit of parts.

Advantages:
• This is the only FRC legal controller
• Seamlessly integrates into the control system
• Relatively durable
• Has extensive documentation in the FRC community
• Is very powerful and is capable of utilizing the full capabilities of the control system

Disadvantages:
• Extremely high cost ($550)



Title: Arduino + RobotOpen Shield
Picture:

Description: This controller was developed by cross the road electronics to act as a drop-in substitute for the cRIO. It works by using the popular robot controller known as the arduino and interfacing it into the FRC control system with a custom PDB

Advantages:
• Low cost
• Drop-in replacement for cRIO

Disadvantages:
• Not FRC legal
• Costs extra to add pneumatic functionality
• Limitted to one digital side-car (cRIO can use two).
 


Title: Vexnet Controller
Picture:

Description: This controller is generally used on smaller Vex Robots, but can also be used to control FRC robots. Vex control systems are produced by IFI, the company that originally produced the FRC control system before the switch to the cRIO in 2009.

Advantages:
• Lower cost than cRIO

Disadvantages:
• Not FRC legal
• Higher cost than Arduino + Robot Open
• Cannot use FRC driver-station, must use vex joystick
• No pneumatic capabilities



Final evaluation:
Two products stood out above the rest:
cRIO - The cRIO is a must-have. Basically because the rules say you must have it ;). It is the only legal way to control an FRC robot and thus it should be used on your competition robot.
Arduino + RobotOpen Shield – This solution is a cost effective way of controlling non-competition robots, such as practice bots. The extremely low price-point and minimal amount of effort require to switch from a cRIO to Aruino make it stand above the other solutions for robots which do not have to be FRC-legal.

I hope that gives everyone an idea of what we’re looking for. It doesn’t have to be as exhaustive as this, but try and get as much information as you can,

- Alex

Re: [4334] Research Project
 

Alright. Everyone has had a few minutes to begin their research, so I’m going to help out anybody who is struggling. Here are the options I would suggest researching for each topic (if you already have something you like, feel free to use that instead):

• Speed controllers:
o Talon, Jaguar, Victor 884, Victor 888

• Chain vs Belt
o Chain, Belt (Easy, no?)

• Gearboxes
o Banebot Planetary, Andymark standard (Spur), Andymark Shifting (Spur + shifting)

• Structural Materials
o 80/20, Aluminum tubing, sheet metal

• Wheels
o Kit wheel, Plaction tires, Colson wheels + WCP hubs, Pnuematic tires

That’s all for now. Keep on researching!
- Alex

Re: [4334] Research Project
 

Title: Jaguar speed controller


Description: One of the only legal FRC speed controllers and is often favored

Advantage: Legal in FRC competition,very linear.

Disadvantages: Can only control one motor per speed controller, overheats

Re: [4334] Research Project
 

Title: Talon Speed Controller (am-2195)
Picture:
Description: The Talon is the latest generation in Brushed DC motor control. The Talon features locked anti-phase rectification that provides more efficient delivery of power to Brushed DC motors. This type of rectification returns current to the power source during the freewheeling period of the motor and during direction change. The passive cooling design reduces the number of entry points for damage causing conductive debris. Any debris that does enter the housing won't get past the conformal coating that protects the surface mount components.
Advantages:
• Small size: 2.73 x 1.90 x 1.15 inches
• Weight: 0.2 pounds
• Cooling methods:
• Passive aluminum heat sink included in all units
• Mounting holes to allow for optional 40 mm fan
• Conformal coating providing resistance to metal chip shorts
• Secure PWM connection
Disadvantages:
• Expensive
•

Re: [4334] Research Project
 

Spur gearboxes have straight teeth mounted on a parallel. The advantages are: low cost, high gear ratios, compact and high torque output. The disadvantages are: high noise level and prone to wear.

Planetary gearboxes include sungear in the center. Ring gear is the outer ring of planetary gearboxes and planetary gears rotate around the center. The advantages are: high power density, compact, efficient, stable and the is low distribution. The disadvantages are: high barring loads, complex design and inaccessibility.

Transmission/Shifters are designed for robots weighing 50-200 pounds. The top equals high gear, high torque equals low gear. Although low gear controllable and uses less current.

-Britton & Amy

Re: [4334] Research Project
 

Title: Jaguar speed controller


Description: One of the only legal FRC speed controllers and is often favored

Advantage: Legal in FRC competition,very linear.

Disadvantages: Can only control one motor per speed controller, overheats

Re: [4334] Research Project
 

Title: Chain
Picture:
Description: Chains transfer power over distances by using sprockets
Advantages: It’s simpler to work with and create
Disadvantages: It’s heavier, it’s know to be less efficient, it’s slower at a set distance, it doesn’t go as far for a given time of power application

Title: Belt
Picture:
Description: Belts transfer power over distances by using sprockets
Advantages: It’s lighter, it’s know to be more efficient, it’s faster at a set distance, it goes further for a given time of power application
Disadvantages: It’s harder to use and create

Re: [4334] Research Project
 

Wheels:
Mecanum wheels
• Description – a drive base that uses four wheels and each wheel driven independently. 6, 8 or 10 inch. All have rollers positioned at 45 degree angles.
• Advantage – each can be driven independently.
• Disadvantage - unstable and complex.
Omni wheels
• Description – are used in highly mobile robots, conveyor systems, and material handling equipment.

• Advantages - These wheels provide propulsion in the forward and reverse direction, while allowing for easy, smooth-rolling sideways motion. Plastic Omni Wheels have two bearings in the bore of the wheel, while Aluminum Omni Wheels only have one. Due the this, the Plastic Omni Wheel is more stable and are less likely to tilt under a significant side load.

• Disadvantages - Durability from a severe impact: Aluminum Omni Wheels are more resilient to a significant impact. Aluminum Omni Wheels will bend under this severe impact, while the Plastic Wheel may crack or break.
Colson performance wheel
• Description - a favorite of combat robot builders. The wheels in this series have been used on all sizes of robots, from 1lb Antweights to 340lb SuperHeavyweights! They are very durable, and provide excellent traction.
• Advantage - both hard and soft tread materials in a single wheel. Like a hard tread wheel, Performa rolls easily and is very durable. Like a soft tread wheel, it rolls quietly, protects floors and resists impacts with a cushion ride. It also features maximum weather ability, low temperature flexibility, resistance to chemicals, water and steam, and rejects floor debris such as metal shavings. Non-marking thermoplastic elastomer tread is permanently bonded to durable polyolefin wheel core.Pl
• Disadvantage – slightly heavy
Plaction Wheels
• Description - are constructed of two black polycarbonate plastic halves, fastened together with six #10 screws and nylock nuts.
• Advantages - For easily replacing this tread (if you don't have tread lacing), install rivets into each end of the tread to insure the tread stays put under heavy usage.
• Disadvantages – the treads get worn off and harder to turn due to size.

Re: [4334] Research Project
 

Structural Materials

Sheet metal quoted form tsaka
"Remember that almost all automobiles are today constructed with a sheet metal body that has no solid frame or chassis underneath it. Automotive engineers gain the strength and rigidity they need from sheet metal by making careful use of the inherent strengths of this material and applying geometric principles to overcome the weaknesses. Done properly, sheet metal produces a very light, strong, and inexpensive frame.

The biggest difficulty that might face a team wanting to make full use of sheet metal in their design is the expense of tooling. Sheet metal can be easily and inexpensively bent and joined in simple shapes to improve strength and rigidity. However, the complex shapes used in automotive bodies required very expensive metal forming equipment. These complex shapes bring sheet metal construction to very high levels of strength and beauty. But as long as you do not want to push the construction technique to the extreme levels used in auto bodies, you can do a lot with this material quickly, and at a modest cost."

Tube
wall 1x1 inch aluminum box 50% weight reduction. Also good for ¼ pound/foot , tougher to build with than 80/20 but lighter and similar strength

80/20
quoted form EOC http://www.chiefdelphi.com/forums/at...7&d=1352834904

Re: [4334] Research Project
 

Structural Materials
Title: Grade 304 Stainless Steel Sheet metal
Picture: N/A


Description: Micro alloyed steel, designed mechanical rather than compositional specs. Has to be under 6mm to be considered sheet metal. Essentially non-magnetic, becomes slightly magnetic when cold worked. 18% chromium and 8% nickel. It corrosive resistant, flexible and durable. Unfortunately it is heavy.
Advantages:
• High strength,
• resistant to atmospheric corrosion.
• Durable
• able to be cut or bent easily
• Most flexible out of all the stainless steel sheets
Disadvantages:
• costs from $200 - $800 depending on the size and quality
• Heavy
•

Re: [4334] Research Project
 

Just as a correction, the RobotOpen Arduino shield was developed by 221 Robotics Systems not cross the road electronics.

Looks like an interesting team development project! I am looking forward to seeing the responses from your member.

Re: [4334] Research Project
 

Title: Victor 884 Speed controller
Picture:
Description: VIctor 884 is a $90 speed controller that is a successor to the Victor 883. it weighs 4 ounces and its operating voltage is 6-15v
Advantages: FRC-Legal, reliable ventilation system, small, cheap ($90), higher current outputs then previous generation

Disadvantages: lower speed at given torque compared to other models, failings in linearity

Re: [4334] Research Project
 

Nice, we did this exact thing in the weeks before the 2012 season started. Students were assigned topics to create research presentations on. We have an extensive list somewhere....

Re: [4334] Research Project
 

Here's the list.
http://www.atomicrobotics.com/studen...arch_projects/