ArduCopter/ArduCopter.pde

 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
-#define THISFIRMWARE "ArduCopter V3.0.0-rc4"
+#define THISFIRMWARE "ArduCopter V3.0.0"
 /*
  *  ArduCopter Version 3.0
  *  Creator:        Jason Short

ArduCopter/Attitude.pde

@@ -122,15 +122,14 @@ get_roll_rate_stabilized_ef(int32_t stick_angle)
         angle_error	= constrain_int32(angle_error, -MAX_ROLL_OVERSHOOT, MAX_ROLL_OVERSHOOT);
     }
 
-    if (motors.armed() == false || ((g.rc_3.control_in == 0) && !ap.failsafe_radio)) {
+    // reset target angle to current angle if motors not spinning
+    if (!motors.armed() || g.rc_3.servo_out == 0) {
         angle_error = 0;
     }
 
     // update roll_axis to be within max_angle_overshoot of our current heading
     roll_axis = wrap_180_cd(angle_error + ahrs.roll_sensor);
 
-    // set earth frame targets for rate controller
-
     // set earth frame targets for rate controller
 	set_roll_rate_target(g.pi_stabilize_roll.get_p(angle_error) + target_rate, EARTH_FRAME);
 }
@@ -158,7 +157,8 @@ get_pitch_rate_stabilized_ef(int32_t stick_angle)
         angle_error	= constrain_int32(angle_error, -MAX_PITCH_OVERSHOOT, MAX_PITCH_OVERSHOOT);
     }
 
-    if (motors.armed() == false || ((g.rc_3.control_in == 0) && !ap.failsafe_radio)) {
+    // reset target angle to current angle if motors not spinning
+    if (!motors.armed() || g.rc_3.servo_out == 0) {
         angle_error = 0;
     }
 
@@ -189,7 +189,8 @@ get_yaw_rate_stabilized_ef(int32_t stick_angle)
     // limit the maximum overshoot
     angle_error	= constrain_int32(angle_error, -MAX_YAW_OVERSHOOT, MAX_YAW_OVERSHOOT);
 
-    if (motors.armed() == false || ((g.rc_3.control_in == 0) && !ap.failsafe_radio)) {
+    // reset target angle to current heading if motors not spinning
+    if (!motors.armed() || g.rc_3.servo_out == 0) {
     	angle_error = 0;
     }
 
@@ -1019,10 +1020,6 @@ get_throttle_rate(float z_target_speed)
         set_throttle_out(g.throttle_cruise+output, true);
     }
 
-    // limit loiter & waypoint navigation from causing too much lean
-    // To-Do: ensure that this limit is cleared when this throttle controller is not running so that loiter is not left constrained for Position mode
-    wp_nav.set_angle_limit(4500 - constrain_float((z_rate_error - 100) * 10, 0, 3500));
-
     // update throttle cruise
     // TO-DO: this may not be correct because g.rc_3.servo_out has not been updated for this iteration
     if( z_target_speed == 0 ) {

ArduCopter/ReleaseNotes.txt

 ArduCopter Release Notes:
 ------------------------------------------------------------------
+ArduCopter 3.0.0 / 3.0.0-rc6 16-Jun-2013
+Improvements over 3.0.0-rc5
+1) bug fix to Circle mode's start position (was moving to last loiter target)
+2) WP_ACCEL parameter added to allow user to adjust acceleration during missions
+3) loiter acceleration set to half of LOIT_SPEED parameter value (was hard-coded)
+4) reduce AltHold P to 1.0 (was 2.0)
+------------------------------------------------------------------
+ArduCopter 3.0.0-rc5 04-Jun-2013
+Improvements over 3.0.0-rc4
+1) bug fix to LAND flight mode in which it could try to fly to mission's next waypoint location
+2) bug fix to Circle mode to allow counter-clockwise rotation
+3) bug fix to heading change in Loiter, RTL, Missions when pilot's throttle is zero
+4) bug fix for mission sticking at take-off command when pilot's throttle is zero
+5) bug fix for parameters not saving when new value is same as default value
+6) reduce pre-arm board min voltage check to 4.3V (was 4.5V)
+7) remove throttle controller's ability to limit lean angle in loiter, rtl, auto
+------------------------------------------------------------------
 ArduCopter 3.0.0-rc4 02-Jun-2013
 Improvements over 3.0.0-rc3
 1) loiter improvements:

ArduCopter/commands_logic.pde

@@ -323,9 +323,20 @@ static void do_land(const struct Location *cmd)
         // set landing state
         land_state = LAND_STATE_DESCENDING;
 
-        // switch to loiter which restores horizontal control to pilot
-        // To-Do: check that we are not in failsafe to ensure we don't process bad roll-pitch commands
-        set_roll_pitch_mode(ROLL_PITCH_LOITER);
+        // if we have gps lock, attempt to hold horizontal position
+        if( ap.home_is_set && g_gps->status() == GPS::GPS_OK_FIX_3D ) {
+            // switch to loiter which restores horizontal control to pilot
+            // To-Do: check that we are not in failsafe to ensure we don't process bad roll-pitch commands
+            set_roll_pitch_mode(ROLL_PITCH_LOITER);
+            // switch into loiter nav mode
+            set_nav_mode(NAV_LOITER);
+        }else{
+            // no gps lock so give horizontal control to pilot
+            // To-Do: check that we are not in failsafe to ensure we don't process bad roll-pitch commands
+            set_roll_pitch_mode(ROLL_PITCH_STABLE);
+            // switch into loiter nav mode
+            set_nav_mode(NAV_NONE);
+        }
 
         // hold yaw while landing
         set_yaw_mode(YAW_HOLD);
@@ -333,8 +344,6 @@ static void do_land(const struct Location *cmd)
         // set throttle mode to land
         set_throttle_mode(THROTTLE_LAND);
 
-        // switch into loiter nav mode
-        set_nav_mode(NAV_LOITER);
     }
 }
 

ArduCopter/config.h

@@ -918,7 +918,7 @@
 #endif
 
 #ifndef ALT_HOLD_P
- # define ALT_HOLD_P            2.0f
+ # define ALT_HOLD_P            1.0f
 #endif
 #ifndef ALT_HOLD_I
  # define ALT_HOLD_I            0.0f

ArduCopter/fence.pde

@@ -36,7 +36,7 @@ void fence_check()
                 init_disarm_motors();
             }else{
                 // if we have a GPS
-                if( ap.home_is_set ) {
+                if( ap.home_is_set && g_gps->status() == GPS::GPS_OK_FIX_3D ) {
                     // if we are within 100m of the fence, RTL
                     if( fence.get_breach_distance(new_breaches) <= AC_FENCE_GIVE_UP_DISTANCE) {
                         if(control_mode != RTL) {
@@ -44,7 +44,7 @@ void fence_check()
                         }
                     }else{
                         // if more than 100m outside the fence just force a land
-                        if(control_mode != RTL) {
+                        if(control_mode != LAND) {
                             set_mode(LAND);
                         }
                     }

ArduCopter/navigation.pde

@@ -68,7 +68,7 @@ static void calc_distance_and_bearing()
     }
 
     // calculate home distance and bearing
-    if( ap.home_is_set ) {
+    if( ap.home_is_set && (g_gps->status() == GPS::GPS_OK_FIX_3D || g_gps->status() == GPS::GPS_OK_FIX_2D)) {
         home_distance = pythagorous2(curr.x, curr.y);
         home_bearing = pv_get_bearing_cd(curr,Vector3f(0,0,0));
 
@@ -103,8 +103,8 @@ static void run_autopilot()
 // set_nav_mode - update nav mode and initialise any variables as required
 static bool set_nav_mode(uint8_t new_nav_mode)
 {
-    // boolean to ensure proper initialisation of nav modes
-    bool nav_initialised = false;
+    bool nav_initialised = false;       // boolean to ensure proper initialisation of nav modes
+    Vector3f stopping_point;            // stopping point for circle mode
 
     // return immediately if no change
     if( new_nav_mode == nav_mode ) {
@@ -119,13 +119,14 @@ static bool set_nav_mode(uint8_t new_nav_mode)
 
         case NAV_CIRCLE:
             // set center of circle to current position
-            circle_set_center(inertial_nav.get_position(), ahrs.yaw);
+            wp_nav.get_stopping_point(inertial_nav.get_position(),inertial_nav.get_velocity(),stopping_point);
+            circle_set_center(stopping_point,ahrs.yaw);
             nav_initialised = true;
             break;
 
         case NAV_LOITER:
             // set target to current position
-            wp_nav.set_loiter_target(inertial_nav.get_position(), inertial_nav.get_velocity());
+            wp_nav.init_loiter_target(inertial_nav.get_position(), inertial_nav.get_velocity());
             nav_initialised = true;
             break;
 
@@ -217,13 +218,14 @@ static void
 circle_set_center(const Vector3f current_position, float heading_in_radians)
 {
     float max_velocity;
+    float cir_radius = g.circle_radius * 100;
 
     // set circle center to circle_radius ahead of current position
-    circle_center.x = current_position.x + (float)g.circle_radius * 100 * cos_yaw;
-    circle_center.y = current_position.y + (float)g.circle_radius * 100 * sin_yaw;
+    circle_center.x = current_position.x + cir_radius * cos_yaw;
+    circle_center.y = current_position.y + cir_radius * sin_yaw;
 
     // if we are doing a panorama set the circle_angle to the current heading
-    if( g.circle_radius == 0 ) {
+    if( g.circle_radius <= 0 ) {
         circle_angle = heading_in_radians;
         circle_angular_velocity_max = ToRad(g.circle_rate);
         circle_angular_acceleration = circle_angular_velocity_max;  // reach maximum yaw velocity in 1 second
@@ -235,13 +237,22 @@ circle_set_center(const Vector3f current_position, float heading_in_radians)
         max_velocity = min(wp_nav.get_horizontal_velocity(), safe_sqrt(0.5f*WPNAV_ACCELERATION*g.circle_radius*100.0f)); 
 
         // angular_velocity in radians per second
-        circle_angular_velocity_max = min(ToRad(g.circle_rate), max_velocity/((float)g.circle_radius * 100.0f));
+        circle_angular_velocity_max = max_velocity/((float)g.circle_radius * 100.0f);
+        circle_angular_velocity_max = constrain_float(ToRad(g.circle_rate),-circle_angular_velocity_max,circle_angular_velocity_max);
+
+        // angular_velocity in radians per second
         circle_angular_acceleration = WPNAV_ACCELERATION/((float)g.circle_radius * 100);
+        if (g.circle_rate < 0.0f) {
+            circle_angular_acceleration = -circle_angular_acceleration;
+        }
     }
 
     // initialise other variables
     circle_angle_total = 0;
     circle_angular_velocity = 0;
+
+    // initialise loiter target.  Note: feed forward velocity set to zero
+    wp_nav.init_loiter_target(current_position, Vector3f(0,0,0));
 }
 
 // update_circle - circle position controller's main call which in turn calls loiter controller with updated target position
@@ -252,9 +263,16 @@ update_circle(float dt)
     Vector3f circle_target;
 
     // ramp up angular velocity to maximum
-    if(circle_angular_velocity < circle_angular_velocity_max){
-        circle_angular_velocity += circle_angular_acceleration * dt;
-        circle_angular_velocity = constrain_float(circle_angular_velocity, 0, circle_angular_velocity_max);
+    if (g.circle_rate >= 0) {
+        if (circle_angular_velocity < circle_angular_velocity_max) {
+            circle_angular_velocity += circle_angular_acceleration * dt;
+            circle_angular_velocity = constrain_float(circle_angular_velocity, 0, circle_angular_velocity_max);
+        }
+    }else{
+        if (circle_angular_velocity > circle_angular_velocity_max) {
+            circle_angular_velocity += circle_angular_acceleration * dt;
+            circle_angular_velocity = constrain_float(circle_angular_velocity, circle_angular_velocity_max, 0);
+        }
     }
 
     // update the target angle

ArduCopter/system.pde

@@ -434,7 +434,7 @@ static void set_mode(uint8_t mode)
 
     case LAND:
         // To-Do: it is messy to set manual_attitude here because the do_land function is reponsible for setting the roll_pitch_mode
-        if( g_gps->status() == GPS::GPS_OK_FIX_3D ) {
+        if( ap.home_is_set && g_gps->status() == GPS::GPS_OK_FIX_3D ) {
             // switch to loiter if we have gps
             ap.manual_attitude = false;
         }else{

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);
@@ -143,8 +153,8 @@ void AC_WPNav::set_loiter_target(const Vector3f& position)
     _target_vel.y = 0;
 }
 
-/// set_loiter_target - set initial loiter target based on current position and velocity
-void AC_WPNav::set_loiter_target(const Vector3f& position, const Vector3f& velocity)
+/// init_loiter_target - set initial loiter target based on current position and velocity
+void AC_WPNav::init_loiter_target(const Vector3f& position, const Vector3f& velocity)
 {
     // set target position and velocity based on current pos and velocity
     _target.x = position.x;
@@ -155,6 +165,14 @@ void AC_WPNav::set_loiter_target(const Vector3f& position, const Vector3f& veloc
     // initialise desired roll and pitch to current roll and pitch.  This avoids a random twitch between now and when the loiter controller is first run
     _desired_roll = constrain_int32(_ahrs->roll_sensor,-MAX_LEAN_ANGLE,MAX_LEAN_ANGLE);
     _desired_pitch = constrain_int32(_ahrs->pitch_sensor,-MAX_LEAN_ANGLE,MAX_LEAN_ANGLE);
+
+    // initialise pilot input
+    _pilot_vel_forward_cms = 0;
+    _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();
 }
 
 /// move_loiter_target - move loiter target by velocity provided in front/right directions in cm/s
@@ -263,24 +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;
 }
 
 ///
@@ -504,12 +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{
@@ -623,18 +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
@@ -672,7 +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){
@@ -680,7 +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);
     }

libraries/AC_WPNav/AC_WPNav.h

@@ -11,7 +11,8 @@
 #include <AP_InertialNav.h>     // 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
@@ -50,8 +51,8 @@ public:
     /// set_loiter_target in cm from home
     void set_loiter_target(const Vector3f& position);
 
-    /// set_loiter_target - set initial loiter target based on current position and velocity
-    void set_loiter_target(const Vector3f& position, const Vector3f& velocity);
+    /// init_loiter_target - set initial loiter target based on current position and velocity
+    void init_loiter_target(const Vector3f& position, const Vector3f& velocity);
 
     /// move_loiter_target - move destination using pilot input
     void move_loiter_target(float control_roll, float control_pitch, float dt);
@@ -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)

libraries/AP_InertialSensor/AP_InertialSensor.cpp

@@ -477,7 +477,7 @@ bool AP_InertialSensor::_calibrate_accel( Vector3f accel_sample[6],
         success = false;
     }
     // sanity check offsets (2.0 is roughly 2/10th of a G, 5.0 is roughly half a G)
-    if( accel_offsets.is_nan() || fabsf(accel_offsets.x) > 2.0f || fabsf(accel_offsets.y) > 2.0f || fabsf(accel_offsets.z) > 3.0f ) {
+    if( accel_offsets.is_nan() || fabsf(accel_offsets.x) > 3.0f || fabsf(accel_offsets.y) > 3.0f || fabsf(accel_offsets.z) > 3.0f ) {
         success = false;
     }