Michael Shimniok / Steering

A class for calculating steering angle calculations based on current and desired heading and specified intercept distance along the new path.

Dependents:   AVC_20110423

Steering.h@0:a3b128cdb78b, 2011-04-27 (annotated)

Committer:
shimniok
Date:
Wed Apr 27 18:55:38 2011 +0000
Revision:
0:a3b128cdb78b
Initial release

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shimniok 0:a3b128cdb78b 1
shimniok 0:a3b128cdb78b 2 #define PI 3.141592653589
shimniok 0:a3b128cdb78b 3
shimniok 0:a3b128cdb78b 4 /** A class for managing steering angle calculations based on current and desired heading
shimniok 0:a3b128cdb78b 5 * and specified intercept distance along the new path.
shimniok 0:a3b128cdb78b 6 *
shimniok 0:a3b128cdb78b 7 * See Notebook entry: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:a3b128cdb78b 8 */
shimniok 0:a3b128cdb78b 9 class Steering
shimniok 0:a3b128cdb78b 10 {
shimniok 0:a3b128cdb78b 11 public:
shimniok 0:a3b128cdb78b 12 /** create a new steering calculator
shimniok 0:a3b128cdb78b 13 *
shimniok 0:a3b128cdb78b 14 * @param wheelbase vehicle wheelbase
shimniok 0:a3b128cdb78b 15 * @param track vehicle track width
shimniok 0:a3b128cdb78b 16 * @param intercept new course intercept distance
shimniok 0:a3b128cdb78b 17 */
shimniok 0:a3b128cdb78b 18 Steering(float wheelbase, float track);
shimniok 0:a3b128cdb78b 19
shimniok 0:a3b128cdb78b 20 /** set intercept distance
shimniok 0:a3b128cdb78b 21 * @param intercept distance along new course at which turn arc will intercept
shimniok 0:a3b128cdb78b 22 */
shimniok 0:a3b128cdb78b 23 void setIntercept(float intercept);
shimniok 0:a3b128cdb78b 24
shimniok 0:a3b128cdb78b 25 /** convert course change to average steering angle
shimniok 0:a3b128cdb78b 26 * assumes Ackerman steering, with track and wheelbase
shimniok 0:a3b128cdb78b 27 * and course intercept distance specified.
shimniok 0:a3b128cdb78b 28 *
shimniok 0:a3b128cdb78b 29 * See notebook: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:a3b128cdb78b 30 *
shimniok 0:a3b128cdb78b 31 * @param theta relative bearing of the new course
shimniok 0:a3b128cdb78b 32 * @returns steering angle in degrees
shimniok 0:a3b128cdb78b 33 */
shimniok 0:a3b128cdb78b 34 float calcSA(float theta);
shimniok 0:a3b128cdb78b 35
shimniok 0:a3b128cdb78b 36 private:
shimniok 0:a3b128cdb78b 37
shimniok 0:a3b128cdb78b 38 inline static float angle_radians(float deg) {return (PI/180.0)*deg;}
shimniok 0:a3b128cdb78b 39
shimniok 0:a3b128cdb78b 40 inline static float angle_degrees(float rad) {return (180/PI)*rad;}
shimniok 0:a3b128cdb78b 41
shimniok 0:a3b128cdb78b 42 float _wheelbase;
shimniok 0:a3b128cdb78b 43 float _track;
shimniok 0:a3b128cdb78b 44 float _intercept;
shimniok 0:a3b128cdb78b 45 };