From 7c5d96385e54e3268b490e658237933d636fe94b Mon Sep 17 00:00:00 2001 From: Randy Mackay Date: Sun, 16 Jun 2013 11:39:54 +0900 Subject: [PATCH] WPNav: add acceleration parameter WP_ACCEL added to allow user control of acceleration during missions. Loiter acceleration made to be half of loiter max speed --- libraries/AC_WPNav/AC_WPNav.cpp | 62 ++++++++++++++++++++++----------- libraries/AC_WPNav/AC_WPNav.h | 5 ++- 2 files changed, 45 insertions(+), 22 deletions(-) diff --git a/libraries/AC_WPNav/AC_WPNav.cpp b/libraries/AC_WPNav/AC_WPNav.cpp index f80be650f0..6ec7c19257 100644 --- a/libraries/AC_WPNav/AC_WPNav.cpp +++ b/libraries/AC_WPNav/AC_WPNav.cpp @@ -10,7 +10,7 @@ const AP_Param::GroupInfo AC_WPNav::var_info[] PROGMEM = { // @Param: SPEED // @DisplayName: Waypoint Horizontal Speed Target // @Description: Defines the speed in cm/s which the aircraft will attempt to maintain horizontally during a WP mission - // @Units: Centimeters/Second + // @Units: cm/s // @Range: 0 2000 // @Increment: 50 // @User: Standard @@ -19,7 +19,7 @@ const AP_Param::GroupInfo AC_WPNav::var_info[] PROGMEM = { // @Param: RADIUS // @DisplayName: Waypoint Radius // @Description: Defines the distance from a waypoint, that when crossed indicates the wp has been hit. - // @Units: Centimeters + // @Units: cm // @Range: 100 1000 // @Increment: 1 // @User: Standard @@ -28,7 +28,7 @@ const AP_Param::GroupInfo AC_WPNav::var_info[] PROGMEM = { // @Param: SPEED_UP // @DisplayName: Waypoint Climb Speed Target // @Description: Defines the speed in cm/s which the aircraft will attempt to maintain while climbing during a WP mission - // @Units: Centimeters/Second + // @Units: cm/s // @Range: 0 1000 // @Increment: 50 // @User: Standard @@ -37,7 +37,7 @@ const AP_Param::GroupInfo AC_WPNav::var_info[] PROGMEM = { // @Param: SPEED_DN // @DisplayName: Waypoint Descent Speed Target // @Description: Defines the speed in cm/s which the aircraft will attempt to maintain while descending during a WP mission - // @Units: Centimeters/Second + // @Units: cm/s // @Range: 0 1000 // @Increment: 50 // @User: Standard @@ -46,12 +46,21 @@ const AP_Param::GroupInfo AC_WPNav::var_info[] PROGMEM = { // @Param: LOIT_SPEED // @DisplayName: Loiter Horizontal Maximum Speed // @Description: Defines the maximum speed in cm/s which the aircraft will travel horizontally while in loiter mode - // @Units: Centimeters/Second + // @Units: cm/s // @Range: 0 2000 // @Increment: 50 // @User: Standard AP_GROUPINFO("LOIT_SPEED", 4, AC_WPNav, _loiter_speed_cms, WPNAV_LOITER_SPEED), + // @Param: ACCEL + // @DisplayName: Waypoint Acceleration + // @Description: Defines the horizontal acceleration in cm/s/s used during missions + // @Units: cm/s/s + // @Range: 0 980 + // @Increment: 10 + // @User: Standard + AP_GROUPINFO("ACCEL", 5, AC_WPNav, _wp_accel_cms, WPNAV_ACCELERATION), + AP_GROUPEND }; @@ -81,6 +90,7 @@ AC_WPNav::AC_WPNav(AP_InertialNav* inav, AP_AHRS* ahrs, APM_PI* pid_pos_lat, APM _vel_last(0,0,0), _lean_angle_max(MAX_LEAN_ANGLE), _loiter_leash(WPNAV_MIN_LEASH_LENGTH), + _loiter_accel_cms(WPNAV_LOITER_ACCEL_MAX), _wp_leash_xy(WPNAV_MIN_LEASH_LENGTH), _wp_leash_z(WPNAV_MIN_LEASH_LENGTH), _track_accel(0), @@ -112,23 +122,23 @@ void AC_WPNav::get_stopping_point(const Vector3f& position, const Vector3f& velo // calculate current velocity vel_total = safe_sqrt(velocity.x*velocity.x + velocity.y*velocity.y); - // avoid divide by zero by using current position if the velocity is below 10cm/s or kP is very low - if (vel_total < 10.0f || kP <= 0.0f) { + // avoid divide by zero by using current position if the velocity is below 10cm/s, kP is very low or acceleration is zero + if (vel_total < 10.0f || kP <= 0.0f || _wp_accel_cms <= 0.0f) { target = position; return; } // calculate point at which velocity switches from linear to sqrt - linear_velocity = WPNAV_ACCELERATION/kP; + linear_velocity = _wp_accel_cms/kP; // calculate distance within which we can stop if (vel_total < linear_velocity) { target_dist = vel_total/kP; } else { - linear_distance = WPNAV_ACCELERATION/(2*kP*kP); - target_dist = linear_distance + (vel_total*vel_total)/(2*WPNAV_ACCELERATION); + linear_distance = _wp_accel_cms/(2.0f*kP*kP); + target_dist = linear_distance + (vel_total*vel_total)/(2.0f*_wp_accel_cms); } - target_dist = constrain_float(target_dist, 0, _loiter_leash*2.0); + target_dist = constrain_float(target_dist, 0, _loiter_leash*2.0f); target.x = position.x + (target_dist * velocity.x / vel_total); target.y = position.y + (target_dist * velocity.y / vel_total); @@ -161,6 +171,7 @@ void AC_WPNav::init_loiter_target(const Vector3f& position, const Vector3f& velo _pilot_vel_right_cms = 0; // set last velocity to current velocity + // To-Do: remove the line below by instead forcing reset_I to be called on the first loiter_update call _vel_last = _inav->get_velocity(); } @@ -270,24 +281,28 @@ void AC_WPNav::calculate_loiter_leash_length() float kP = _pid_pos_lat->kP(); // avoid divide by zero - if (kP <= 0.0f) { + if (kP <= 0.0f || _wp_accel_cms <= 0.0f) { _loiter_leash = WPNAV_MIN_LEASH_LENGTH; + _loiter_accel_cms = _loiter_leash / 2.0f; // set loiter acceleration to 1/2 loiter speed return; } // calculate horiztonal leash length - if(_loiter_speed_cms <= WPNAV_ACCELERATION / kP) { + if(_loiter_speed_cms <= _wp_accel_cms / kP) { // linear leash length based on speed close in _loiter_leash = _loiter_speed_cms / kP; }else{ // leash length grows at sqrt of speed further out - _loiter_leash = (WPNAV_ACCELERATION / (2.0*kP*kP)) + (_loiter_speed_cms*_loiter_speed_cms / (2*WPNAV_ACCELERATION)); + _loiter_leash = (_wp_accel_cms / (2.0f*kP*kP)) + (_loiter_speed_cms*_loiter_speed_cms / (2.0f*_wp_accel_cms)); } // ensure leash is at least 1m long if( _loiter_leash < WPNAV_MIN_LEASH_LENGTH ) { _loiter_leash = WPNAV_MIN_LEASH_LENGTH; } + + // set loiter acceleration to 1/2 loiter speed + _loiter_accel_cms = _loiter_leash / 2.0f; } /// @@ -511,12 +526,12 @@ void AC_WPNav::get_loiter_position_to_velocity(float dt, float max_speed_cms) dist_error.x = _target.x - curr.x; dist_error.y = _target.y - curr.y; - linear_distance = WPNAV_ACCELERATION/(2*kP*kP); + linear_distance = _wp_accel_cms/(2.0f*kP*kP); _distance_to_target = linear_distance; // for reporting purposes dist_error_total = safe_sqrt(dist_error.x*dist_error.x + dist_error.y*dist_error.y); - if( dist_error_total > 2*linear_distance ) { - vel_sqrt = safe_sqrt(2*WPNAV_ACCELERATION*(dist_error_total-linear_distance)); + if( dist_error_total > 2.0f*linear_distance ) { + vel_sqrt = safe_sqrt(2.0f*_wp_accel_cms*(dist_error_total-linear_distance)); desired_vel.x = vel_sqrt * dist_error.x/dist_error_total; desired_vel.y = vel_sqrt * dist_error.y/dist_error_total; }else{ @@ -630,18 +645,23 @@ void AC_WPNav::calculate_wp_leash_length(bool climb) // get loiter position P float kP = _pid_pos_lat->kP(); + // sanity check acceleration and avoid divide by zero + if (_wp_accel_cms <= 0.0f) { + _wp_accel_cms = WPNAV_ACCELERATION_MIN; + } + // avoid divide by zero if (kP <= 0.0f) { _wp_leash_xy = WPNAV_MIN_LEASH_LENGTH; return; } // calculate horiztonal leash length - if(_wp_speed_cms <= WPNAV_ACCELERATION / kP) { + if(_wp_speed_cms <= _wp_accel_cms / kP) { // linear leash length based on speed close in _wp_leash_xy = _wp_speed_cms / kP; }else{ // leash length grows at sqrt of speed further out - _wp_leash_xy = (WPNAV_ACCELERATION / (2.0*kP*kP)) + (_wp_speed_cms*_wp_speed_cms / (2*WPNAV_ACCELERATION)); + _wp_leash_xy = (_wp_accel_cms / (2.0f*kP*kP)) + (_wp_speed_cms*_wp_speed_cms / (2.0f*_wp_accel_cms)); } // ensure leash is at least 1m long @@ -679,7 +699,7 @@ void AC_WPNav::calculate_wp_leash_length(bool climb) _track_speed = 0; _track_leash_length = WPNAV_MIN_LEASH_LENGTH; }else if(_pos_delta_unit.z == 0){ - _track_accel = WPNAV_ACCELERATION/pos_delta_unit_xy; + _track_accel = _wp_accel_cms/pos_delta_unit_xy; _track_speed = _wp_speed_cms/pos_delta_unit_xy; _track_leash_length = _wp_leash_xy/pos_delta_unit_xy; }else if(pos_delta_unit_xy == 0){ @@ -687,7 +707,7 @@ void AC_WPNav::calculate_wp_leash_length(bool climb) _track_speed = speed_vert/pos_delta_unit_z; _track_leash_length = _wp_leash_z/pos_delta_unit_z; }else{ - _track_accel = min(WPNAV_ALT_HOLD_ACCEL_MAX/pos_delta_unit_z, WPNAV_ACCELERATION/pos_delta_unit_xy); + _track_accel = min(WPNAV_ALT_HOLD_ACCEL_MAX/pos_delta_unit_z, _wp_accel_cms/pos_delta_unit_xy); _track_speed = min(speed_vert/pos_delta_unit_z, _wp_speed_cms/pos_delta_unit_xy); _track_leash_length = min(_wp_leash_z/pos_delta_unit_z, _wp_leash_xy/pos_delta_unit_xy); } diff --git a/libraries/AC_WPNav/AC_WPNav.h b/libraries/AC_WPNav/AC_WPNav.h index 9901281c54..5fa5885f27 100644 --- a/libraries/AC_WPNav/AC_WPNav.h +++ b/libraries/AC_WPNav/AC_WPNav.h @@ -11,7 +11,8 @@ #include // Inertial Navigation library // loiter maximum velocities and accelerations -#define WPNAV_ACCELERATION 250.0f // defines the velocity vs distant curve. maximum acceleration in cm/s/s that position controller asks for from acceleration controller +#define WPNAV_ACCELERATION 250.0f // defines the default velocity vs distant curve. maximum acceleration in cm/s/s that position controller asks for from acceleration controller +#define WPNAV_ACCELERATION_MIN 50.0f // minimum acceleration in cm/s/s - used for sanity checking _wp_accel parameter #define WPNAV_ACCEL_MAX 980.0f // max acceleration in cm/s/s that the loiter velocity controller will ask from the lower accel controller. // should be 1.5 times larger than WPNAV_ACCELERATION. // max acceleration = max lean angle * 980 * pi / 180. i.e. 23deg * 980 * 3.141 / 180 = 393 cm/s/s @@ -200,6 +201,7 @@ protected: AP_Float _wp_speed_up_cms; // climb speed target in cm/s AP_Float _wp_speed_down_cms; // descent speed target in cm/s AP_Float _wp_radius_cm; // distance from a waypoint in cm that, when crossed, indicates the wp has been reached + AP_Float _wp_accel_cms; // acceleration in cm/s/s during missions uint32_t _loiter_last_update; // time of last update_loiter call uint32_t _wpnav_last_update; // time of last update_wpnav call float _cos_yaw; // short-cut to save on calcs required to convert roll-pitch frame to lat-lon frame @@ -219,6 +221,7 @@ protected: Vector3f _vel_last; // previous iterations velocity in cm/s int32_t _lean_angle_max; // maximum lean angle. can be set from main code so that throttle controller can stop leans that cause copter to lose altitude float _loiter_leash; // loiter's horizontal leash length in cm. used to stop the pilot from pushing the target location too far from the current location + float _loiter_accel_cms; // loiter's acceleration in cm/s/s // waypoint controller internal variables Vector3f _origin; // starting point of trip to next waypoint in cm from home (equivalent to next_WP)