Michael Shimniok / Mbed 2 deprecated DataBus

Code for autonomous rover for Sparkfun AVC. DataBus won 3rd in 2012 and the same code was used on Troubled Child, a 1986 Jeep Grand Wagoneer to win 1st in 2014.

Dependencies:   mbed Watchdog SDFileSystem DigoleSerialDisp

Actuators/Steering/Steering.h@25:bb5356402687, 2018-11-30 (annotated)

Committer:
shimniok
Date:
Fri Nov 30 16:11:53 2018 +0000
Revision:
25:bb5356402687
Parent:
15:01fb4916a5cd 
Initial publish of revised version.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shimniok 2:fbc6e3cf3ed8 1 #ifndef __STEERING_H
shimniok 2:fbc6e3cf3ed8 2 #define __STEERING_H
shimniok 0:a6a169de725f 3
shimniok 2:fbc6e3cf3ed8 4 #include "globals.h"
shimniok 15:01fb4916a5cd 5 #include "devices.h"
shimniok 15:01fb4916a5cd 6 #include "Servo.h"
shimniok 15:01fb4916a5cd 7 #include "Config.h"
shimniok 0:a6a169de725f 8
shimniok 0:a6a169de725f 9 /** A class for managing steering angle calculations based on current and desired heading
shimniok 0:a6a169de725f 10 * and specified intercept distance along the new path.
shimniok 0:a6a169de725f 11 *
shimniok 0:a6a169de725f 12 * See Notebook entry: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:a6a169de725f 13 */
shimniok 0:a6a169de725f 14 class Steering
shimniok 0:a6a169de725f 15 {
shimniok 0:a6a169de725f 16 public:
shimniok 15:01fb4916a5cd 17 /** create a new steering calculator */
shimniok 15:01fb4916a5cd 18 Steering(PinName pin);
shimniok 15:01fb4916a5cd 19
shimniok 15:01fb4916a5cd 20 /** Initalize steering actuator (servo)
shimniok 15:01fb4916a5cd 21 *
shimniok 15:01fb4916a5cd 22 */
shimniok 15:01fb4916a5cd 23 void initSteering(void);
shimniok 15:01fb4916a5cd 24
shimniok 15:01fb4916a5cd 25
shimniok 15:01fb4916a5cd 26 /** Set the track width (left to right contact patch distance)
shimniok 0:a6a169de725f 27 *
shimniok 15:01fb4916a5cd 28 * @param track is the vehicle track width
shimniok 0:a6a169de725f 29 */
shimniok 15:01fb4916a5cd 30 void setTrack(float track);
shimniok 15:01fb4916a5cd 31
shimniok 15:01fb4916a5cd 32
shimniok 15:01fb4916a5cd 33 /** Set the wheelbase (front to rear axle distance)
shimniok 15:01fb4916a5cd 34 *
shimniok 15:01fb4916a5cd 35 * @param wheelbase is the vehicle wheelbase
shimniok 15:01fb4916a5cd 36 */
shimniok 15:01fb4916a5cd 37 void setWheelbase(float wheelbase);
shimniok 15:01fb4916a5cd 38
shimniok 0:a6a169de725f 39
shimniok 0:a6a169de725f 40 /** set intercept distance
shimniok 0:a6a169de725f 41 * @param intercept distance along new course at which turn arc will intercept
shimniok 0:a6a169de725f 42 */
shimniok 0:a6a169de725f 43 void setIntercept(float intercept);
shimniok 0:a6a169de725f 44
shimniok 15:01fb4916a5cd 45
shimniok 15:01fb4916a5cd 46 /** set steering scale factor to convert between steering angle and servo output
shimniok 15:01fb4916a5cd 47 * @param scale is the scale factor
shimniok 15:01fb4916a5cd 48 */
shimniok 15:01fb4916a5cd 49 void setScale(float scale);
shimniok 15:01fb4916a5cd 50
shimniok 15:01fb4916a5cd 51
shimniok 15:01fb4916a5cd 52 /** Convert steerAngle to servo value
shimniok 15:01fb4916a5cd 53 *
shimniok 15:01fb4916a5cd 54 * Testing determined near linear conversion between servo ms setting and steering angle
shimniok 15:01fb4916a5cd 55 * up to ~20*.
shimniok 15:01fb4916a5cd 56 *
shimniok 15:01fb4916a5cd 57 * @param steerAngle is the steering angle, measured at front wheels, averaged
shimniok 15:01fb4916a5cd 58 */
shimniok 15:01fb4916a5cd 59 void setSteering(float steerAngle);
shimniok 15:01fb4916a5cd 60
shimniok 15:01fb4916a5cd 61
shimniok 15:01fb4916a5cd 62 /** Shorthand for the write function */
shimniok 15:01fb4916a5cd 63 float operator= (float steerAngle);
shimniok 15:01fb4916a5cd 64
shimniok 15:01fb4916a5cd 65
shimniok 0:a6a169de725f 66 /** convert course change to average steering angle
shimniok 0:a6a169de725f 67 * assumes Ackerman steering, with track and wheelbase
shimniok 0:a6a169de725f 68 * and course intercept distance specified.
shimniok 0:a6a169de725f 69 *
shimniok 0:a6a169de725f 70 * See notebook: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:a6a169de725f 71 *
shimniok 0:a6a169de725f 72 * @param theta relative bearing of the new course
shimniok 0:a6a169de725f 73 * @returns steering angle in degrees
shimniok 0:a6a169de725f 74 */
shimniok 0:a6a169de725f 75 float calcSA(float theta);
shimniok 0:a6a169de725f 76
shimniok 15:01fb4916a5cd 77
shimniok 0:a6a169de725f 78 /** convert course change to average steering angle
shimniok 0:a6a169de725f 79 * assumes Ackerman steering, with track and wheelbase
shimniok 0:a6a169de725f 80 * and course intercept distance specified. Also, |radius| of turn is limited to limit
shimniok 0:a6a169de725f 81 *
shimniok 0:a6a169de725f 82 * See notebook: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/
shimniok 0:a6a169de725f 83 *
shimniok 0:a6a169de725f 84 * @param theta relative bearing of the new course
shimniok 0:a6a169de725f 85 * @param limit is the limit of the turn circle radius (absolute value)
shimniok 0:a6a169de725f 86 * @returns steering angle in degrees
shimniok 0:a6a169de725f 87 */
shimniok 0:a6a169de725f 88 float calcSA(float theta, float limit);
shimniok 0:a6a169de725f 89
shimniok 15:01fb4916a5cd 90
shimniok 0:a6a169de725f 91 /** compute steering angle based on pure pursuit algorithm
shimniok 0:a6a169de725f 92 */
shimniok 0:a6a169de725f 93 float purePursuitSA(float hdg, float Bx, float By, float Ax, float Ay, float Cx, float Cy);
shimniok 0:a6a169de725f 94
shimniok 15:01fb4916a5cd 95
shimniok 0:a6a169de725f 96 /** compute steering angle based on a simpler path pursuit variant of pure pursuit
shimniok 0:a6a169de725f 97 */
shimniok 0:a6a169de725f 98 float pathPursuitSA(float hdg, float Bx, float By, float Ax, float Ay, float Cx, float Cy);
shimniok 0:a6a169de725f 99
shimniok 15:01fb4916a5cd 100
shimniok 0:a6a169de725f 101 /** Compute cross track error given last waypoint, next waypoint, and robot coordinates
shimniok 0:a6a169de725f 102 * @returns cross track error
shimniok 0:a6a169de725f 103 */
shimniok 0:a6a169de725f 104 float crossTrack(float Bx, float By, float Ax, float Ay, float Cx, float Cy);
shimniok 15:01fb4916a5cd 105
shimniok 0:a6a169de725f 106
shimniok 15:01fb4916a5cd 107 /** Convert degrees to radians
shimniok 15:01fb4916a5cd 108 * @param deg degrees to convert
shimniok 15:01fb4916a5cd 109 * @return radians
shimniok 15:01fb4916a5cd 110 */
shimniok 15:01fb4916a5cd 111 inline static float toRadians(float deg) {return (PI/180.0)*deg;}
shimniok 15:01fb4916a5cd 112
shimniok 0:a6a169de725f 113
shimniok 15:01fb4916a5cd 114 /** Convert radians to degrees
shimniok 15:01fb4916a5cd 115 * @param rad radians to convert
shimniok 15:01fb4916a5cd 116 * @return degrees
shimniok 15:01fb4916a5cd 117 */
shimniok 15:01fb4916a5cd 118 inline static float toDegrees(float rad) {return (180/PI)*rad;}
shimniok 0:a6a169de725f 119
shimniok 15:01fb4916a5cd 120 private:
shimniok 15:01fb4916a5cd 121 Servo _steering; // Steering Servo
shimniok 15:01fb4916a5cd 122 float _scale; // Steering scale factor
shimniok 15:01fb4916a5cd 123 float _track; // vehicle track used for steering intercept calc
shimniok 15:01fb4916a5cd 124 float _wheelbase; // vehicle wheelbase used for steering intercept calc
shimniok 15:01fb4916a5cd 125 float _intercept; // circle intercept distance
shimniok 2:fbc6e3cf3ed8 126 };
shimniok 2:fbc6e3cf3ed8 127
shimniok 15:01fb4916a5cd 128 #endif