Lesson 2

Lesson 2

1. Now, it is time to decide on the type if robot you are going to build. A custom robot design often starts with a “vision” of what the robot will look like and what it will do. The most popular types of robots are: Land wheeled, tracked, and legged robots. Aerial planes, helicopters, and blimp. Aquatic boats, submarines, and swimming robots. Misc. and mixed robots. Stationary robot arms, and manipulators.

   • Descriptions
     • Land
       • most popular mobile robots among beginners as they usually require the least investment while providing significant exposure to robotics.
         • Advantages
           • -Usually low-cost compared to other methods -Simple design and construction -Abundance of choice -Six wheels or more rival a track system -Excellent choice for beginners
         • Disadvantages
           • -May lose traction (slip) -Small contact area (only a small rectangle or line underneath each wheel is in contact with the ground)
     • Tracked Robots
       • Tracks (or treads) are what tanks use. Although tracks do not provide added “force” (torque), they do reduce slip and more evenly distribute the weight of the robot, making them useful for loose surfaces such as sand and gravel. Also, a track system with some flexibility can better conform to a bumpy surface. Finally, most people tend to agree that tank tracks add an “aggressive” look to the robot as well.
         • Advantages
           • -Constant contact with the ground prevents slipping that might occur with wheels -Evenly distributed weight helps your robot tackle a variety of surfaces -Can be used to significantly increase a robot’s ground clearance without incorporating a larger drive wheel
         • Disadvantages
           • -When turning, there is a sideways force that acts on the ground; this can cause damage to the surface the robot is being used on, and cause the tracks to wear -Not many different tracks are available -Drive sprocket might significantly limit the number of motors that can be used.
     • Legs
       • Legs are often preferred for robots that must navigate on very uneven terrain. Most amateur robots are designed with six legs, which allow the robot to be statically balanced
         • Advantages
           • -Closer to organic or natural motion -Can potentially overcome large obstacles and navigate very rough terrain
         • Disadvantages
           • -Increased mechanical, electronic and coding complexity. -Lower battery size despite increased power demands -Higher cost to build
     • Miscellaneous and hybrid combinations
       • Your idea for a robot may not fall nicely into any of the above categories or may be comprised of several different functional sections. Note again that this guide is intended for mobile robots as opposed to stationary or permanently fixed designs. It is wise to consider when building a hybrid design, to use a modular design . Miscellaneous designs can include hovercraft, snake-like designs, turrets and more.
         • Advantages
           • -Designed and built to meet specific needs -Multi-tasking and can be comprised of modules -Can lead to increased functionality and versatility
         • Disadvantages
           • -Possible Increased complexity and cost -Often times, parts must be custom designed and built
     • Water
       • There are many obstacles yet to overcome to make underwater robots attractive to the wider robotic community though in recent years, several companies have commercialized pool cleaning “robots”. Underwater vehicles can use ballast , thrusters, tail and fins or even wings to submerge. Other aquatic robots such as pool cleaners are useful commercial products.
         • Advantages
           • -Design is almost guaranteed to be unique -Can be used and/or tested in a pool -Most of our planet is water, so there is a lot to explore and discover
         • Disadvantages
           • -Robot can be lost many ways -Most electronic parts do not like water -Surpassing depths of 10m or more can require significant research and investment -Very limited robotic community to provide help -Limited wireless communication options
     • Air
       • Is very appealing and is entirely within the capability of many robot enthusiasts. most hobbyists still use existing commercial remote controlled aircraft. On the professional side, aircraft such as the US military Predator were initially semi-autonomous though in recent years Predator aircraft have flown missions autonomously.
         • Advantages
           • -Remote controlled aircraft have been in existence for decades -Excellent for surveillance
         • Disadvantages
           • -The entire investment can be lost in one crash. -Limited robotic community to provide help for autonomous control
     • Arms & Grippers
       • Arms and grippers are the best way for a robot to interact with the environment it is exploring. Simple robot arms can have just one motion, while more complex arms can have a dozen or more unique degrees of freedom.
         • Advantages
           • -Very simple to very complex design possibilities -Easy to make a 3 or 4 degree of freedom robot arm
         • Disadvantages
           • -Stationary unless mounted on a mobile platform -Cost to build is proportional to lifting capability