# Difference between revisions of "Tutorials/Arduino Projects/Additional Info/Turning Calculations"

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== Differential Steering == | == Differential Steering == | ||

− | For a differential drive system, the "center point" where all the turning calculations are based from is based on the location of all the various driving wheels. To keep the process simple, we recommend that you try to keep the wheels evenly spaced so the center is just half way between all the wheels. If the system has a caster, then you can just ignore it for simplicity. | + | For a differential drive system, the "center point" where all the turning calculations are based from is based on the location of all the various driving wheels. To keep the process simple, we recommend that you try to keep the wheels evenly spaced so the center is just half way between all the wheels. If the system has a caster, then you can just ignore it for simplicity. |

− | + | ||

For the calculations we will say that the distance between the wheels from one side to the other is W. We will also say that the desired swing radius from the center is R, and the desired speed is V. The speed of the left side will be defined as V<sub>L</sub> and the speed of the right side as V<sub>R</sub>. | For the calculations we will say that the distance between the wheels from one side to the other is W. We will also say that the desired swing radius from the center is R, and the desired speed is V. The speed of the left side will be defined as V<sub>L</sub> and the speed of the right side as V<sub>R</sub>. | ||

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[[image:Differential_Steering_Graphic_4_wheels.png|thumb|c|center|400px|]] | [[image:Differential_Steering_Graphic_4_wheels.png|thumb|c|center|400px|]] | ||

[[image:Differential_Steering_Graphic_2_wheels.png|thumb|c|center|400px|]] | [[image:Differential_Steering_Graphic_2_wheels.png|thumb|c|center|400px|]] | ||

− | [[image: | + | [[image:Differential_Steering_R_Equation.png|center|]] |

− | [[image: | + | [[image:Differential_Steering_V_Equation.png|center|]] |

− | [[image: | + | [[image:Differential_Steering_VL_Equation.png|center|]] |

− | [[image: | + | [[image:Differential_Steering_VR_Equation.png|center|]] |

+ | {{Todo|Could add Kinematic equations for (X,Y) and robot orientation angle.}} | ||

+ | |||

+ | == Ackermann Steering == | ||

+ | Ackermann steering is the steering system used in just about every automobile. Normally the center point is located between a pair of fixed wheels. However this system can have the "center point" located anywhere you want. We will define the distance from the center point to the wheel length-wise as H. We will also define the turning radius as R. We will define the angle of the left and right wheels as Θ<sub>L</sub> and Θ<sub>R</sub> respectively. We will also define W as the distance between the wheels on each side. | ||

+ | [[image:Ackermann_Steering_Graphic.png|thumb|c|center|400px|]] | ||

+ | [[image:Ackermann_Steering_Left_angle.png|center|]] | ||

+ | [[image:Ackermann_Steering_Right_angle.png|center|]] | ||

+ | {{Note|you can add additional pivoting wheels. Just change the value of H to the distance for those wheels.}} | ||

− | + | {{Todo|Could add Kinematic equations for (X,Y) and robot orientation angle.}} |

## Latest revision as of 18:51, 8 August 2012

## Differential Steering

For a differential drive system, the "center point" where all the turning calculations are based from is based on the location of all the various driving wheels. To keep the process simple, we recommend that you try to keep the wheels evenly spaced so the center is just half way between all the wheels. If the system has a caster, then you can just ignore it for simplicity.

For the calculations we will say that the distance between the wheels from one side to the other is W. We will also say that the desired swing radius from the center is R, and the desired speed is V. The speed of the left side will be defined as V_{L} and the speed of the right side as V_{R}.

## Ackermann Steering

Ackermann steering is the steering system used in just about every automobile. Normally the center point is located between a pair of fixed wheels. However this system can have the "center point" located anywhere you want. We will define the distance from the center point to the wheel length-wise as H. We will also define the turning radius as R. We will define the angle of the left and right wheels as Θ_{L} and Θ_{R} respectively. We will also define W as the distance between the wheels on each side.