The Physics of

Mark Dobbins , Mike Grayson, Jennifer Burton

www.battlebots.com

What is a BattleBot?

A remote controlled combat robot

• Remote control

• Internal power

• Movement mechanisms

• Protective mechanisms

• Weapons

Weight

• Weight is an essential part of the BattleBot which defines what other bots it will face.

Weight Class (lbs) Min Max

Lightweight 30 60

Middleweight 60 120

Heavyweight 120 220

Super Heavyweight

220 340

• Every pound counts– Power Supply– Motors– Wheels– Armor– Weapons– Nuts & Bolts

Control

• Handheld Transmitter• Internal Receiver

• Internal Logic• Connections to Motors

Innovation First, Inc. Robot Controls

• Operator Interface– Switches and Joysticks

• Radio Modem– 900 MHz radio signal– 19200 bps

• FRC Robot Controller– Data from Operator Interface and Onboard Sensors– Internal microcontroller with some user programming

capabilities

Power

• Internal Batteries– Lead-Acid batteries are required to be “leak-

proof”

• Battery “Hold-Downs”• Wiring and Fuses• Strong wire connections

• Fuel-Powered Engines are sometimes used in place of electric motors

Judging Competition

• A bot that is immobilized looses the match.• Points are awarded for:

– Aggression– Strategy– Damage

Weapons

• Inflict maximum damage without self-destructing– Cut– Smash– Lift– Throw

• Weapons can be:– Gasoline powered– Electric– Pneumatic– Hydraulic.

Saw Weapons

• Most effective saws are gas-powered (more kick) and are horizontally mounted

• Blades can be easily damaged by a side impact if mounted vertically

• Does very little damage

Spinning Disc Weapons

• Often confused with saw weapons, but work on a different principle• Builds up kinetic energy and delivers it in one fast blow

– A combination of high rpm and a large diameter, which generate very fast speeds on the outer perimeter

– But for every action there is a reaction, so you had better have a sturdy system to absorb or allow for shock on your bot as well.

“Scorpion” or Spike Weapons

• A spike must retract and eject with a great deal of speed.• Usually powered by pneumatics• Frequent use causes the expanding air to cool in the

cylinder. Later strikes have less force. (pv=nrt)• An ejection mechanism

can also be achieved

using a winch and some

large springs to store the

energy

Flipping Weapons

• Some bots can be incapacitated when flipped upside down

• Some bots are invertible and can only be damaged, not incapacitated, by flipping weapons.

• Pneumatics or linear actuators are usually used to power flipping devices.

Clamp Weapons

• allow a bot to grab onto and control the opponent and perhaps lift it off the ground as well, or use an arena hazard to damage it.

• getting hold of the opponent when they are moving around and attacking is harder than it sounds

Drill Weapons

• Drills can do quite a bit of damage but they probably take too long to be effective under most circumstances

Types of Movement

Wheels (taken from remote control cars)Single ball (works like non-optical mouse)Walkers (fallen out of style because of ineptitude)Tread (like army vehicles)

Defensive tactic #1

• Little to no ground clearance• Curtains• Edges close to the ground to prevent flipping• Disadvantage

– Makes it harder

to maneuver. – Not 100 percent

effective.

Defensive Tactic #2

• Speed or Agility

• Advantage: run from competitor and its weapons

• Disadvantage: not enough mass for impact with competitor.

Defensive Tactic #3

• Strength: more mass

• Advantage: able to overpower the offense

• Disadvantage: dynamic stability takes a hit, less agility

Defensive Tactic #4

• Armor Plating

• All battlebots have it to some degree

• Protects the electronics

• There is an inverse relationship between material used and dynamic stability

Skills

• No matter what defensive precautions are taken, skill is what really matters

• The best BattleBot could lose if run by a bad tactician or uneducated person.