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
- Committer:
- shimniok
- Date:
- 2018-11-29
- Revision:
- 15:01fb4916a5cd
- Parent:
- 2:fbc6e3cf3ed8
File content as of revision 15:01fb4916a5cd:
#ifndef __STEERING_H #define __STEERING_H #include "globals.h" #include "devices.h" #include "Servo.h" #include "Config.h" /** A class for managing steering angle calculations based on current and desired heading * and specified intercept distance along the new path. * * See Notebook entry: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/ */ class Steering { public: /** create a new steering calculator */ Steering(PinName pin); /** Initalize steering actuator (servo) * */ void initSteering(void); /** Set the track width (left to right contact patch distance) * * @param track is the vehicle track width */ void setTrack(float track); /** Set the wheelbase (front to rear axle distance) * * @param wheelbase is the vehicle wheelbase */ void setWheelbase(float wheelbase); /** set intercept distance * @param intercept distance along new course at which turn arc will intercept */ void setIntercept(float intercept); /** set steering scale factor to convert between steering angle and servo output * @param scale is the scale factor */ void setScale(float scale); /** Convert steerAngle to servo value * * Testing determined near linear conversion between servo ms setting and steering angle * up to ~20*. * * @param steerAngle is the steering angle, measured at front wheels, averaged */ void setSteering(float steerAngle); /** Shorthand for the write function */ float operator= (float steerAngle); /** convert course change to average steering angle * assumes Ackerman steering, with track and wheelbase * and course intercept distance specified. * * See notebook: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/ * * @param theta relative bearing of the new course * @returns steering angle in degrees */ float calcSA(float theta); /** convert course change to average steering angle * assumes Ackerman steering, with track and wheelbase * and course intercept distance specified. Also, |radius| of turn is limited to limit * * See notebook: http://mbed.org/users/shimniok/notebook/smooth-steering-for-rc-car/ * * @param theta relative bearing of the new course * @param limit is the limit of the turn circle radius (absolute value) * @returns steering angle in degrees */ float calcSA(float theta, float limit); /** compute steering angle based on pure pursuit algorithm */ float purePursuitSA(float hdg, float Bx, float By, float Ax, float Ay, float Cx, float Cy); /** compute steering angle based on a simpler path pursuit variant of pure pursuit */ float pathPursuitSA(float hdg, float Bx, float By, float Ax, float Ay, float Cx, float Cy); /** Compute cross track error given last waypoint, next waypoint, and robot coordinates * @returns cross track error */ float crossTrack(float Bx, float By, float Ax, float Ay, float Cx, float Cy); /** Convert degrees to radians * @param deg degrees to convert * @return radians */ inline static float toRadians(float deg) {return (PI/180.0)*deg;} /** Convert radians to degrees * @param rad radians to convert * @return degrees */ inline static float toDegrees(float rad) {return (180/PI)*rad;} private: Servo _steering; // Steering Servo float _scale; // Steering scale factor float _track; // vehicle track used for steering intercept calc float _wheelbase; // vehicle wheelbase used for steering intercept calc float _intercept; // circle intercept distance }; #endif