Calculating+Turns

How to calculate turns.

Circumference is the distance around a circle once. Being able to calculate the circumference of a circle or wheel is the starting point for programming a robot.

__Calculate Circumference__ using on of these these formulas: Circumference = 2 X Radius X 3.1416 or Circumference = Diameter X 3.1316

__Two Important Dimensions__

Wheel diameter and the distance between the wheels must be known to accurately program the movement of a robot. The distance between the wheels is also called axle length.

__Wheel Circumference__ Circumference is the distance around a wheel. The circumference of the wheels is important because the distance a wheel travels in one rotation is the wheel's circumference.

In a formula this is:

Distance traveled = Wheel-Circumference X Wheel Rotations or Distance = Wheel-Cir X Rots

Use these formulas to calculate the rotations needed by both wheels to go a specific distance. Also use these formulas to determine the rotations needed by one wheel to go a specific turn-distance.

[|Video and Presentation on How to Calculate Going a Distance]

Swing Turn The outside wheel travels on a circle during a swing turn. (Video At this link: http://www.education.rec.ri.cmu.edu/content/electronics/boe/robot_motion/images/making%20swing%20turns.webm )

__Turn Circle Circumference__ For two wheels connected by an axle, if one wheel rotates and the other doesn't, the turning wheel will go in a circle. This is called the Turn-Circle or T-Circle and is the blue circle shown below. The distance between the wheels or axle length is the radius of the Turn-Circle. The circumference of the Turn-Circle can be calculated using the axle length as the radius.

To calculate a turn, the distance the wheel must travel on the turn-circle must be determined. This can be done by putting the turn-angle and turn-circle-circumference into the formula below.
 * __Turn Angle__ || = || __Turn-Distance__ ||  ||   ||   ||   ||   ||   ||
 * 360 ||  || Turn-Circle ||   ||   ||   ||   ||   ||   ||

[|Video and presentation Explanation of Turning] [|Video and presentation Explanation of How to Calculate a Turn] This link has another short explanation.

Calculate Circumference using these formulas: Circumference = 2 X Radius X 3.1416 or Circumference = Diameter X 3.1316

Determine the circumference of the wheel. Wheel Diameter is 5cm Wheel Circumference =

Determine the Circumference of the Turn circle. The axle of the robot is 12.5 cm. T-Circle Circumference =

How many program degrees are required for a robot to turn 137 degrees? Step 1 - Determine the Turn-Distance. Step 2 - Use the Turn-Distance to determine the number of rotations needed for the wheel to go this distance. Step 3 - Multiple the rotations by 360 if you want to program in degrees instead of rotations.

How many program degrees are required for a robot to turn 274 degree?

More problems and practice.