Turning Radius
From BEAM Robotics Wiki
- A term used when referring to the smallest circular path (other than pivoting in place) that a particular wheeled robot is capable of traversing. Factors involved in limiting just how tight a turn the robot is capable of executing include:
- The overall dimensions of the robot (Track and {Wheelbase)
- The steering technique used by the robot
- The functional capabilities of the driving and steering mechanisms used by the robot
The turning radius is not always presented as a specific numerical figure. Rather, it is often used in a generalized way.
For example, a robot that uses differential or skid steering can turn in a complete circle in a relatively small area by driving one wheel while the other remains stationary. It would not be unusual for this kind of robot to be described as having a "very tight turning radius".
However, a numeric figure for the turning radius of a particular robot can be determined by measuring the distance from the center point of a circular path executed by that robot, to the outer edge of that circular path.
Also, when designing a robot (for example, one utilizing car-like steering) it is possible to closely approximate what the turning radius will be. The following formula is crude but works well enough. Be sure to use consistent units of measure when entering numeric values.
Where:
- Track = The distance between the center of the left wheel to the center of the right wheel on the same axle, or, which shares a common axis.
- Wheelbase = The distance between the center of the front wheel axle to the center of the rear wheel axle, both wheels being on the same side.
- Maximum steering angle = the most extreme position towards the center of a turn to which the steering mechanism is capable of turning the wheels.
- For a Parallel steering configuration this will be equal to the maximum steering angle of either of the steerable wheels.
- For an Ackerman steering configuration this will be average of the maximum steering angles of both the left and right steerable wheels.
Note: The above formula only provides the Turning radius for the wheels and does not account for any part of the robot's frame or cover that might overhang the turning radius as determined using the above formula.
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