Michael Shimniok / Mbed 2 deprecated AVC_2012

Code for autonomous ground vehicle, Data Bus, 3rd place winner in 2012 Sparkfun AVC.

Dependencies:   Watchdog mbed Schedule SimpleFilter LSM303DLM PinDetect DebounceIn Servo

Actuators/Steering/Steering.h@0:826c6171fc1b, 2012-06-20 (annotated)

Committer:
shimniok
Date:
Wed Jun 20 14:57:48 2012 +0000
Revision:
0:826c6171fc1b
Updated documentation

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shimniok 0:826c6171fc1b 1
shimniok 0:826c6171fc1b 2 #define PI 3.141592653589
shimniok 0:826c6171fc1b 3
shimniok 0:826c6171fc1b 4 /** A class for managing steering angle calculations based on current and desired heading
shimniok 0:826c6171fc1b 5 * and specified intercept distance along the new path.
shimniok 0:826c6171fc1b 6 *
shimniok 0:826c6171fc1b 7 * See Notebook entry: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:826c6171fc1b 8 */
shimniok 0:826c6171fc1b 9 class Steering
shimniok 0:826c6171fc1b 10 {
shimniok 0:826c6171fc1b 11 public:
shimniok 0:826c6171fc1b 12 /** create a new steering calculator
shimniok 0:826c6171fc1b 13 *
shimniok 0:826c6171fc1b 14 * @param wheelbase vehicle wheelbase
shimniok 0:826c6171fc1b 15 * @param track vehicle track width
shimniok 0:826c6171fc1b 16 * @param intercept new course intercept distance
shimniok 0:826c6171fc1b 17 */
shimniok 0:826c6171fc1b 18 Steering(float wheelbase, float track);
shimniok 0:826c6171fc1b 19
shimniok 0:826c6171fc1b 20 /** set intercept distance
shimniok 0:826c6171fc1b 21 * @param intercept distance along new course at which turn arc will intercept
shimniok 0:826c6171fc1b 22 */
shimniok 0:826c6171fc1b 23 void setIntercept(float intercept);
shimniok 0:826c6171fc1b 24
shimniok 0:826c6171fc1b 25 /** convert course change to average steering angle
shimniok 0:826c6171fc1b 26 * assumes Ackerman steering, with track and wheelbase
shimniok 0:826c6171fc1b 27 * and course intercept distance specified.
shimniok 0:826c6171fc1b 28 *
shimniok 0:826c6171fc1b 29 * See notebook: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:826c6171fc1b 30 *
shimniok 0:826c6171fc1b 31 * @param theta relative bearing of the new course
shimniok 0:826c6171fc1b 32 * @returns steering angle in degrees
shimniok 0:826c6171fc1b 33 */
shimniok 0:826c6171fc1b 34 float calcSA(float theta);
shimniok 0:826c6171fc1b 35
shimniok 0:826c6171fc1b 36 /** convert course change to average steering angle
shimniok 0:826c6171fc1b 37 * assumes Ackerman steering, with track and wheelbase
shimniok 0:826c6171fc1b 38 * and course intercept distance specified. Also, |radius| of turn is limited to limit
shimniok 0:826c6171fc1b 39 *
shimniok 0:826c6171fc1b 40 * See notebook: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:826c6171fc1b 41 *
shimniok 0:826c6171fc1b 42 * @param theta relative bearing of the new course
shimniok 0:826c6171fc1b 43 * @param limit is the limit of the turn circle radius (absolute value)
shimniok 0:826c6171fc1b 44 * @returns steering angle in degrees
shimniok 0:826c6171fc1b 45 */
shimniok 0:826c6171fc1b 46 float calcSA(float theta, float limit);
shimniok 0:826c6171fc1b 47
shimniok 0:826c6171fc1b 48 /** compute steering angle based on pure pursuit algorithm
shimniok 0:826c6171fc1b 49 */
shimniok 0:826c6171fc1b 50 float purePursuitSA(float hdg, float Bx, float By, float Ax, float Ay, float Bx, float By);
shimniok 0:826c6171fc1b 51
shimniok 0:826c6171fc1b 52 /** Compute cross track error given last waypoint, next waypoint, and robot coordinates
shimniok 0:826c6171fc1b 53 * @returns cross track error
shimniok 0:826c6171fc1b 54 */
shimniok 0:826c6171fc1b 55 float crossTrack(float Bx, float By, float Ax, float Ay, float Bx, float By);
shimniok 0:826c6171fc1b 56
shimniok 0:826c6171fc1b 57 private:
shimniok 0:826c6171fc1b 58
shimniok 0:826c6171fc1b 59 inline static float angle_radians(float deg) {return (PI/180.0)*deg;}
shimniok 0:826c6171fc1b 60
shimniok 0:826c6171fc1b 61 inline static float angle_degrees(float rad) {return (180/PI)*rad;}
shimniok 0:826c6171fc1b 62
shimniok 0:826c6171fc1b 63 float _wheelbase;
shimniok 0:826c6171fc1b 64 float _track;
shimniok 0:826c6171fc1b 65 float _intercept;
shimniok 0:826c6171fc1b 66 };