How to Build a Mobile Robot OR, Better Still: How NOT to Build a Mobile Robot

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Marshall Griffith
5 years ago
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1 How to Build a Mobile Robot OR, Better Still: How NOT to Build a Mobile Robot Tom Carroll Robot Builder s TYPICAL QUESTIONS * Wheeled or Tracks? R/C or Autonomous? Large or Small Robot? * Nuts & Bolts or Welded? * Mounting Wheels to Robot? * 2, 3, 4 or 6 or more Wheels? First Timer or Experienced? Wood, Plastic, Aluminum or Steel? * Keeping Wheels Contacting Ground? * Mounting Wheels to Gearmotor / Servo Types of Arms & Mass Compensation? * Gas Spring & Infinity Cable? * Types of Steering? Easy or Complex? Using Gears?

2 April 1984 Popular Mechanics Charlie by Jim Hill Made by using only Hand Tools

3 Jim was a auto dealership Parts Manager and the only power tool that he used was a power drill

4 Boy s Life- magazine for Boy Scouts I was a scoutmaster at the time that I wrote this article and my twin sons, scouts, help me design a robot that could be built for under $50 from a trashcan, two surplus dual motors and Radio Shack items

5 Gismo-2-BL was made from a trashcan and simple parts available at Radio Shack with the two dual motors (for Wheels and Arms) obtained from Surplus Big Track motors

6 Fellow SRS member, Pete Miles and I wrote this book on Building Your Own Combat Robot We re still getting a few pennies tossed our way from McGraw Hill

7 I mentored Ridgefield Middle School Students in a Robotics Club They had used LEGO Mind storms in the past and wanted to design and build their own robots We used VEX and ServoCity parts

8 Stars Build Robot for:

I gave them a quote but they hesitated, and suddenly said go for

9 Living in Southern California, 20th Century Fox had heard of me and asked me to build 4 action prop robots for a new film. I gave them a quote but they hesitated, and suddenly said go for it and tossed any amount of money that I asked for to complete the robots.

10 First, a foam board mockup for dimensions, then go for the mechanics- base structure, wheel chair motors, driver electronics, large Gel-cells, terminal strips & wiring harnesses.

11 Dail DeVilleneuve of Vantec supplied the modified 18-channel R/C system and the electronic speed controls. (note- the 12 key keypad on the transmitter and the KeyKoder in his other hand) I had worked with Dail in the past on many promotional and movie robots. His Vantec systems hold up better than most other systems, especially when set decorators and prop operators are using the systems.

12 One of the completed Revenge of the Nerds Robots. Two action prop robots (full electronics and motorized wheel) and two non-action props that looked identical were built. The jocks in one scene wrecked one of the action props when they sacked the house of the nerds. I ll discuss the arm mechanisms later.

13 Beverly Hills children s dentist, David Powell asked me to build an action robot for his office. I used similar control systems that I used on the Revenge of the Nerds robots, but this robot was taller and bent at the waist. Unlike a movie prop, this robot had to withstand years of use by his office staff entertaining children in his waiting room. Yellow Arrow Points to Spring-Loaded Wheel Caster to prevent High-Siding of Robot s Wheels on Uneven Ground. We ll Look at Another Design Later

14 The DCP2000 robot, as it was called, bent at the waist, its arms and head moved and it had a moving LED sign display in its chest. The arms did not bend at the elbows as did the Revenge bots. I hired two out of work friends to work out of my garage (I had my job at Rockwell) and we had to form two different Fiberglas shells in case he wanted to change the robot s clothes.

15 TV Journalist interviews David Hanson s Philip K. Dick Humanoid

16 Ken Maxon and one of his amazing robots

17 Beautifully machined wheel hubs and mounts

18 More Machine Work

19 Ken s new CNC Mill

20 Dave Shinsel introduces his robot, Loki to the Portland Robotics group about 5 years ago Dave scrounged parts from all sorts of places, such as Campbell Soup cans for the eyes

21 Mark Curry and his SRS RoboMagellan Robot, Nomad

22 Seattle Robotics RoboMagellan contest at the Seattle Center on a sunny day!

23 Carol Hazlet & a few of her Friends

24 Unique Robot construction Welded rebar and ServoCity Actobotics structural channels

25 Tetrix Channel ServoCity Channel

26 Aluminum Tile Transition metal Strip

27 Basic Parallax Propeller-Bas ed ActivityBot

28 Parallax Propeller-Ba sed ActivityBot With many add-ons

29 Mars 2020 Rover Note: 6-wheel Rocker Bogie Arrangement &Differential Ba at top of robot

30 Rocker Bogie Mobile Robot with Differential Bar

31 Students Trying different Wheel Assembly Designs for their Robot

32 Final Designs for the Wheel Assemblies Four of the Wheels Steer and two center ones are fixed in fore-aft positions

33 Motor Mounted to a Wheel

34 Motor Mounted to a Wheel

35 Pneumatic Tires, Machined Hubs, wheel Encoders Originally Designed for the Eddie Robot and now used on the Arlo Platform

36 VEX Clawbot using a Beam Structure Note the mounting of the four Wheels and the Interconnecting Gear

37 Beam Offers Structure Flexibility and Robot Simplicity Platform

38 Uses Another Simple Welded Platform Differential Using a Belt-Driven System to Drive WheelsWheels Parallax Heavy-Duty Motorized Steering as Wheels don t Steer

39 BUT Heavy-Duty Robot Chassis with Chain Drive & Differential Steering Inflexible Wheel Mounting not Good

40 Differential Drive with Caster Well - Designed

41 Six-Wheeled Robot Must use Differential Steering (and Skid in Turns) BUT Shock-Loaded Wheels Will Traverse Uneven Ground Easily

42 Closer Look at Shock System and Center Channel Structure

43 Another Shock System and 3DP Mounts- Still Requires Skids on a Turn

44 Spring Loading Casters in Differential Drive Robots to Keep Drive Wheels on Ground

45 Tank Treads may look Cool and can climb Stairs and Such But they Eat Up Battery Life with Friction Think About It

46 More Tank Treads Looks Great!

47 Simple Differential Steering using a Fore and Aft Caster Remember to Have at Least One Caster Spring-Loaded

48 Ackermann (car-type) Steering Not Popular for Robots but Used on Model Car Racing Note Angles of Steering Connections to Wheels and Point that they meet at Center of Back Axel

49 Curiosity s

50 Avoid Trying to Use Gears to change Motor Speeds Use a Gearmotor or Chain / Belt Drives

53 Compound Gears Change Speeds Note Middle Gear has two Sizes and number of Teeth

54 OWI Robotic Arm Edge $45

55 Using a single Motor Per Robot Arm to Raise Arm in a Natural Motion This is the Same Pulley - Cable Arrangement as Used on the Revenge of the Nerds Robot

57 Questions??

Spare Parts. Contents. Contents Contents

Spare Parts. Contents. Contents Contents Spare Parts 2013 Spare Parts Contents Contents Contents LEGO Education StoryStarter 3 LEGO Education WeDo 4 Machines and Mechanisms 5 LEGO MINDSTORMS Education 6-8 TETRIX by Pitsco 9-16 LEGOeducation.us