mc_pos_control: migrate MPC_*_VEL_* parameter to acceleration scaling

Before #14212 the velocity control gains used in the multicopter
position controller were defined as a scale between velocity error in
one axis (or it's integral and derivative respectively) and the unit
thrust vector. The problem with this is that the normalization of the
unit thrust vector changes per vehicle or even vehicle configuration
as 0 and 100% thrust get a different physical response. That's why
the gains are now defined as scale between velocity error
(integral/derivative) and the output acceleration in m/s².

ROMFS/px4fmu_common/init.d-posix/1040_standard_vtol

@@ -25,9 +25,9 @@ then
 	param set MPC_THR_MIN 0.1
 	param set MPC_TKO_SPEED 1
 	param set MPC_XY_P 0.8
-	param set MPC_XY_VEL_D 0.005
-	param set MPC_XY_VEL_I 0.2
-	param set MPC_XY_VEL_P 0.15
+	param set MPC_XY_VEL_P_ACC 3
+	param set MPC_XY_VEL_I_ACC 4
+	param set MPC_XY_VEL_D_ACC 0.1
 	param set MPC_Z_VEL_MAX_DN 1.5
 
 	param set NAV_ACC_RAD 5

ROMFS/px4fmu_common/init.d-posix/1041_tailsitter

@@ -25,11 +25,11 @@ then
 	param set MPC_THR_MIN 0.1
 	param set MPC_TKO_SPEED 1
 	param set MPC_XY_P 0.15
-	param set MPC_XY_VEL_D 0.005
-	param set MPC_XY_VEL_I 0.2
-	param set MPC_XY_VEL_P 0.05
+	param set MPC_XY_VEL_D_ACC 0.1
+	param set MPC_XY_VEL_I_ACC 4
+	param set MPC_XY_VEL_P_ACC 1
 	param set MPC_Z_VEL_MAX_DN 1.5
-	param set MPC_Z_VEL_P 0.8
+	param set MPC_Z_VEL_P_ACC 16
 
 	param set NAV_ACC_RAD 5
 	param set NAV_LOITER_RAD 80

ROMFS/px4fmu_common/init.d-posix/1042_tiltrotor

@@ -25,11 +25,11 @@ then
 	param set MPC_THR_MIN 0.1
 	param set MPC_TKO_SPEED 1
 	param set MPC_XY_P 0.15
-	param set MPC_XY_VEL_D 0.005
-	param set MPC_XY_VEL_I 0.2
-	param set MPC_XY_VEL_P 0.05
+	param set MPC_XY_VEL_D_ACC 0.1
+	param set MPC_XY_VEL_I_ACC 4
+	param set MPC_XY_VEL_P_ACC 1
 	param set MPC_Z_VEL_MAX_DN 1.5
-	param set MPC_Z_VEL_P 0.8
+	param set MPC_Z_VEL_P_ACC 16
 
 	param set NAV_ACC_RAD 5
 	param set NAV_LOITER_RAD 80

ROMFS/px4fmu_common/init.d-posix/6011_typhoon_h480

@@ -15,8 +15,8 @@ then
 	param set MC_ROLLRATE_P 0.15
 	param set MC_ROLLRATE_I 0.1
 	param set MC_ROLL_P 6.0
-	param set MPC_XY_VEL_I 0.2
-	param set MPC_XY_VEL_P 0.15
+	param set MPC_XY_VEL_I_ACC 4
+	param set MPC_XY_VEL_P_ACC 3
 
 	param set RTL_DESCEND_ALT 10
 	param set RTL_LAND_DELAY 0

ROMFS/px4fmu_common/init.d-posix/rcS

@@ -161,12 +161,12 @@ then
 
 	param set MPC_ALT_MODE 0
 	param set MPC_HOLD_MAX_Z 2
-	param set MPC_Z_VEL_I 0.15
-	param set MPC_Z_VEL_P 0.6
+	param set MPC_Z_VEL_P_ACC 12.0
+	param set MPC_Z_VEL_I_ACC 3.0
 	param set MPC_XY_P 0.8
-	param set MPC_XY_VEL_P 0.2
-	param set MPC_XY_VEL_I 0.02
-	param set MPC_XY_VEL_D 0.016
+	param set MPC_XY_VEL_P_ACC 4.0
+	param set MPC_XY_VEL_I_ACC 0.4
+	param set MPC_XY_VEL_D_ACC 0.32
 
 	param set MPC_SPOOLUP_TIME 0.5
 	param set MPC_TKO_RAMP_T 1

ROMFS/px4fmu_common/init.d/airframes/1002_standard_vtol.hil

@@ -39,12 +39,12 @@ then
 	param set MPC_THR_MIN 0.1
 	param set MPC_TKO_SPEED 1
 	param set MPC_XY_P 0.8
-	param set MPC_XY_VEL_D 0.005
-	param set MPC_XY_VEL_I 0.2
-	param set MPC_XY_VEL_P 0.15
-	param set MPC_Z_VEL_I 0.15
+	param set MPC_XY_VEL_D_ACC 0.1
+	param set MPC_XY_VEL_I_ACC 4
+	param set MPC_XY_VEL_P_ACC 3
+	param set MPC_Z_VEL_P_ACC 12
+	param set MPC_Z_VEL_I_ACC 3
 	param set MPC_Z_VEL_MAX_DN 1.5
-	param set MPC_Z_VEL_P 0.6
 
 	param set NAV_ACC_RAD 5
 	param set NAV_DLL_ACT 2

ROMFS/px4fmu_common/init.d/airframes/13006_vtol_standard_delta

@@ -41,7 +41,7 @@ then
 	param set MC_YAWRATE_MAX 50
 
 	param set MPC_XY_P 0.8
-	param set MPC_XY_VEL_P 0.1
+	param set MPC_XY_VEL_P_ACC 2
 	param set MPC_ACC_HOR_MAX 2
 	param set MPC_YAWRAUTO_MAX 20
 

ROMFS/px4fmu_common/init.d/airframes/13009_vtol_spt_ranger

@@ -55,9 +55,9 @@ then
 	param set MPC_TKO_SPEED   1
 	param set MPC_XY_P    0.3
 	param set MPC_XY_VEL_MAX  3
-	param set MPC_XY_VEL_P    0.05
+	param set MPC_XY_VEL_P_ACC 1
 	param set MPC_Z_P 0.5
-	param set MPC_Z_VEL_P 0.1
+	param set MPC_Z_VEL_P_ACC 2
 	param set MPC_YAWRAUTO_MAX 40
 
 	param set NAV_ACC_RAD 3

ROMFS/px4fmu_common/init.d/airframes/13013_deltaquad

@@ -93,7 +93,7 @@ then
 	param set MIS_TAKEOFF_ALT 15
 
 	param set MPC_XY_P 0.8
-	param set MPC_XY_VEL_P 0.1
+	param set MPC_XY_VEL_P_ACC 2
 	param set MPC_XY_VEL_MAX 5
 	param set MPC_ACC_HOR_MAX 2
 	param set MPC_LAND_SPEED 1.2

ROMFS/px4fmu_common/init.d/airframes/4016_holybro_px4vision

@@ -92,11 +92,11 @@ then
 	param set MPC_VEL_MANUAL 5
 	param set MPC_XY_CRUISE 5
 	param set MPC_XY_VEL_MAX 5
-	param set MPC_XY_VEL_P 0.079
+	param set MPC_XY_VEL_P_ACC 1.58
 	param set MPC_XY_TRAJ_P 0.3
 	param set MPC_Z_TRAJ_P 0.3
-	param set MPC_Z_VEL_I 0.15
-	param set MPC_Z_VEL_P 0.25
+	param set MPC_Z_VEL_P_ACC 5
+	param set MPC_Z_VEL_I_ACC 3
 	param set MPC_LAND_ALT1 3
 	param set MPC_LAND_ALT2 1
 

ROMFS/px4fmu_common/init.d/airframes/4052_holybro_qav250

@@ -48,7 +48,7 @@ then
 	param set MPC_THR_CURVE 1
 	param set MPC_THR_HOVER 0.25
 	param set MPC_THR_MIN 0.05
-	param set MPC_Z_VEL_I 0.085
+	param set MPC_Z_VEL_I_ACC 1.7
 
 	param set PWM_MAX 1950
 	param set PWM_MIN 1050

ROMFS/px4fmu_common/init.d/airframes/4070_aerofc

@@ -56,12 +56,12 @@ then
 	param set MPC_THR_MIN 0.1000
 	param set MPC_XY_CRUISE 8.0000
 	param set MPC_XY_P 1.5000
-	param set MPC_XY_VEL_P 0.1500
+	param set MPC_XY_VEL_P_ACC 3
 	param set MPC_Z_P 1.5000
-	param set MPC_Z_VEL_I 0.1500
+	param set MPC_Z_VEL_P_ACC 16
+	param set MPC_Z_VEL_I_ACC 3
 	param set MPC_Z_VEL_MAX_DN 4.0000
 	param set MPC_Z_VEL_MAX_UP 5.0000
-	param set MPC_Z_VEL_P 0.8000
 
 	# TELEM2 config
 	param set MAV_1_CONFIG 102

ROMFS/px4fmu_common/init.d/airframes/4071_ifo

@@ -81,18 +81,17 @@ then
 
 	# Position control
 	param set MPC_Z_P 1.00000
-	param set MPC_Z_VEL_P 0.20000
-	param set MPC_Z_VEL_I 0.02000
-	param set MPC_Z_VEL_D 0.00000
+	param set MPC_Z_VEL_P_ACC 4
+	param set MPC_Z_VEL_I_ACC 0.4
 
 	param set MPC_THR_MIN 0.06000
 	param set MPC_THR_HOVER 0.3000
 
 	param set MIS_TAKEOFF_ALT 1.1000
 	param set MPC_XY_P 1.7000
-	param set MPC_XY_VEL_P 0.1300
-	param set MPC_XY_VEL_I 0.0600
-	param set MPC_XY_VEL_D 0.0100
+	param set MPC_XY_VEL_P_ACC 2.6
+	param set MPC_XY_VEL_I_ACC 1.2
+	param set MPC_XY_VEL_D_ACC 0.2
 	param set MPC_TKO_RAMP_T 1.0000
 	param set MPC_TKO_SPEED 1.1000
 	param set MPC_VEL_MANUAL 3.0000

ROMFS/px4fmu_common/init.d/airframes/4073_ifo-s

@@ -90,18 +90,17 @@ then
 
 	# Position control
 	param set MPC_Z_P 1.10000
-	param set MPC_Z_VEL_P 0.30000
-	param set MPC_Z_VEL_I 0.05000
-	param set MPC_Z_VEL_D 0.00000
+	param set MPC_Z_VEL_P_ACC 6
+	param set MPC_Z_VEL_I_ACC 1
 
 	param set MPC_THR_MIN 0.06000
 	param set MPC_THR_HOVER 0.4400
 
 	param set MIS_TAKEOFF_ALT 1.1000
 	param set MPC_XY_P 1.7000
-	param set MPC_XY_VEL_P 0.1300
-	param set MPC_XY_VEL_I 0.0600
-	param set MPC_XY_VEL_D 0.0100
+	param set MPC_XY_VEL_P_ACC 2.6
+	param set MPC_XY_VEL_I_ACC 1.2
+	param set MPC_XY_VEL_D_ACC 0.2
 	param set MPC_TKO_RAMP_T 1.0000
 	param set MPC_TKO_SPEED 1.1000
 	param set MPC_VEL_MANUAL 3.0000

ROMFS/px4fmu_common/init.d/airframes/4250_teal

@@ -153,15 +153,15 @@ then
 	param set MPC_ACC_HOR_MAX 15
 
 	param set MPC_XY_P 1.15
-	param set MPC_XY_VEL_P 0.14
-	param set MPC_XY_VEL_I 0.014
-	param set MPC_XY_VEL_D 0.014
+	param set MPC_XY_VEL_P_ACC 2.8
+	param set MPC_XY_VEL_I_ACC 0.28
+	param set MPC_XY_VEL_D_ACC 0.28
 	param set MPC_XY_VEL_MAX 26.5
 
 	param set MPC_Z_P 0.85
-	param set MPC_Z_VEL_P 0.25
-	param set MPC_Z_VEL_I 0.085
-	param set MPC_Z_VEL_D 0.02
+	param set MPC_Z_VEL_P_ACC 5
+	param set MPC_Z_VEL_I_ACC 1.7
+	param set MPC_Z_VEL_D_ACC 0.4
 	# Documentation says limit is 8.0, but does not seem to be enforced in code.
 	param set MPC_Z_VEL_MAX_UP 20
 	param set MPC_Z_VEL_MAX_DN 2.5

ROMFS/px4fmu_common/init.d/airframes/4500_clover4

@@ -27,9 +27,9 @@ then
 	param set MC_ROLLRATE_I 0.037
 	param set MC_ROLLRATE_D 0.0044
 	param set MC_ROLL_P 8.5
-	param set MPC_XY_VEL_P 0.11
-	param set MPC_XY_VEL_D 0.013
+	param set MPC_XY_VEL_P_ACC 2.2
+	param set MPC_XY_VEL_D_ACC 0.26
 	param set MPC_XY_P 1.1
-	param set MPC_Z_VEL_P 0.24
+	param set MPC_Z_VEL_P_ACC 4.8
 	param set MPC_Z_P 1.2
 fi

ROMFS/px4fmu_common/init.d/airframes/4900_crazyflie

@@ -53,8 +53,8 @@ then
 	param set MPC_THR_HOVER 0.7
 	param set MPC_THR_MAX 1
 	param set MPC_Z_P 1.5
-	param set MPC_Z_VEL_I 0.3
-	param set MPC_Z_VEL_P 0.4
+	param set MPC_Z_VEL_P_ACC 8
+	param set MPC_Z_VEL_I_ACC 6
 	param set MPC_HOLD_MAX_XY 0.1
 	param set MPC_MAX_FLOW_HGT 3
 

ROMFS/px4fmu_common/init.d/airframes/6002_draco_r

@@ -63,14 +63,13 @@ then
 	param set MPC_THR_HOVER 0.3000
 	# altitude control gains
 	param set MPC_Z_P 1.00000
-	param set MPC_Z_VEL_P 0.20000
-	param set MPC_Z_VEL_I 0.02000
-	param set MPC_Z_VEL_D 0.00000
+	param set MPC_Z_VEL_P_ACC 4
+	param set MPC_Z_VEL_I_ACC 0.4
 	# position control gains
 	param set MPC_XY_P 0.9500
-	param set MPC_XY_VEL_P 0.0900
-	param set MPC_XY_VEL_I 0.0200
-	param set MPC_XY_VEL_D 0.0100
+	param set MPC_XY_VEL_P_ACC 1.8
+	param set MPC_XY_VEL_I_ACC 0.4
+	param set MPC_XY_VEL_D_ACC 0.2
 	# etc gains
 	param set MPC_TKO_RAMP_T 0.4000
 	param set MPC_TKO_SPEED 1.5000

src/lib/parameters/param_translation.cpp

@@ -41,6 +41,15 @@
 
 bool param_modify_on_import(bson_node_t node)
 {
+	// migrate MPC_*_VEL_* -> MPC_*_VEL_*_ACC (2020-04-27). This can be removed after the next release (current release=1.10)
+	if (node->type == BSON_DOUBLE) {
+		param_migrate_velocity_gain(node, "MPC_XY_VEL_P");
+		param_migrate_velocity_gain(node, "MPC_XY_VEL_I");
+		param_migrate_velocity_gain(node, "MPC_XY_VEL_D");
+		param_migrate_velocity_gain(node, "MPC_Z_VEL_P");
+		param_migrate_velocity_gain(node, "MPC_Z_VEL_I");
+		param_migrate_velocity_gain(node, "MPC_Z_VEL_D");
+	}
 
 	// migrate MC_DTERM_CUTOFF -> IMU_DGYRO_CUTOFF (2020-03-12). This can be removed after the next release (current release=1.10)
 	if (node->type == BSON_DOUBLE) {
@@ -148,3 +157,12 @@ bool param_modify_on_import(bson_node_t node)
 
 	return false;
 }
+
+void param_migrate_velocity_gain(bson_node_t node, const char *parameter_name)
+{
+	if (strcmp(parameter_name, node->name) == 0) {
+		strcat(node->name, "_ACC");
+		node->d *= 20.0;
+		PX4_INFO("migrating %s (removed) -> %s: new value=%.3f", parameter_name, node->name, node->d);
+	}
+}

src/lib/parameters/param_translation.h

@@ -36,3 +36,4 @@
 #include "tinybson/tinybson.h"
 
 __EXPORT bool param_modify_on_import(bson_node_t node);
+__EXPORT void param_migrate_velocity_gain(bson_node_t node, const char *parameter_name);

src/modules/mc_pos_control/Takeoff/Takeoff.cpp

@@ -37,11 +37,12 @@
 
 #include "Takeoff.hpp"
 #include <mathlib/mathlib.h>
+#include <lib/ecl/geo/geo.h>
 
-void Takeoff::generateInitialRampValue(const float hover_thrust, float velocity_p_gain)
+void Takeoff::generateInitialRampValue(float velocity_p_gain)
 {
 	velocity_p_gain = math::max(velocity_p_gain, 0.01f);
-	_takeoff_ramp_vz_init = -hover_thrust / velocity_p_gain;
+	_takeoff_ramp_vz_init = -CONSTANTS_ONE_G / velocity_p_gain;
 }
 
 void Takeoff::updateTakeoffState(const bool armed, const bool landed, const bool want_takeoff,

src/modules/mc_pos_control/Takeoff/Takeoff.hpp

@@ -68,7 +68,7 @@ public:
 	 * @param hover_thrust normalized thrsut value with which the vehicle hovers
 	 * @param velocity_p_gain proportional gain of the velocity controller to calculate the thrust
 	 */
-	void generateInitialRampValue(const float hover_thrust, const float velocity_p_gain);
+	void generateInitialRampValue(const float velocity_p_gain);
 
 	/**
 	 * Update the state for the takeoff.

src/modules/mc_pos_control/Takeoff/TakeoffTest.cpp

@@ -34,6 +34,7 @@
 #include <gtest/gtest.h>
 #include <Takeoff.hpp>
 #include <drivers/drv_hrt.h>
+#include <lib/ecl/geo/geo.h>
 
 TEST(TakeoffTest, Initialization)
 {
@@ -46,7 +47,7 @@ TEST(TakeoffTest, RegularTakeoffRamp)
 	Takeoff takeoff;
 	takeoff.setSpoolupTime(1.f);
 	takeoff.setTakeoffRampTime(2.0);
-	takeoff.generateInitialRampValue(.5f, 1.f);
+	takeoff.generateInitialRampValue(CONSTANTS_ONE_G / 0.5f);
 
 	// disarmed, landed, don't want takeoff
 	takeoff.updateTakeoffState(false, true, false, 1.f, false, 0);

src/modules/mc_pos_control/mc_pos_control_main.cpp

@@ -150,12 +150,12 @@ private:
 		// Position Control
 		(ParamFloat<px4::params::MPC_XY_P>) _param_mpc_xy_p,
 		(ParamFloat<px4::params::MPC_Z_P>) _param_mpc_z_p,
-		(ParamFloat<px4::params::MPC_XY_VEL_P>) _param_mpc_xy_vel_p,
-		(ParamFloat<px4::params::MPC_XY_VEL_I>) _param_mpc_xy_vel_i,
-		(ParamFloat<px4::params::MPC_XY_VEL_D>) _param_mpc_xy_vel_d,
-		(ParamFloat<px4::params::MPC_Z_VEL_P>) _param_mpc_z_vel_p,
-		(ParamFloat<px4::params::MPC_Z_VEL_I>) _param_mpc_z_vel_i,
-		(ParamFloat<px4::params::MPC_Z_VEL_D>) _param_mpc_z_vel_d,
+		(ParamFloat<px4::params::MPC_XY_VEL_P_ACC>) _param_mpc_xy_vel_p_acc,
+		(ParamFloat<px4::params::MPC_XY_VEL_I_ACC>) _param_mpc_xy_vel_i_acc,
+		(ParamFloat<px4::params::MPC_XY_VEL_D_ACC>) _param_mpc_xy_vel_d_acc,
+		(ParamFloat<px4::params::MPC_Z_VEL_P_ACC>) _param_mpc_z_vel_p_acc,
+		(ParamFloat<px4::params::MPC_Z_VEL_I_ACC>) _param_mpc_z_vel_i_acc,
+		(ParamFloat<px4::params::MPC_Z_VEL_D_ACC>) _param_mpc_z_vel_d_acc,
 		(ParamFloat<px4::params::MPC_XY_VEL_MAX>) _param_mpc_xy_vel_max,
 		(ParamFloat<px4::params::MPC_Z_VEL_MAX_UP>) _param_mpc_z_vel_max_up,
 		(ParamFloat<px4::params::MPC_Z_VEL_MAX_DN>) _param_mpc_z_vel_max_dn,
@@ -362,12 +362,10 @@ MulticopterPositionControl::parameters_update(bool force)
 		}
 
 		_control.setPositionGains(Vector3f(_param_mpc_xy_p.get(), _param_mpc_xy_p.get(), _param_mpc_z_p.get()));
-		// backwards compatibility scale for velocity gains to non-acceleration based control, needs to be overcome with configuration conversion
-		const float hover_scale = 20.f;
-		_control.setVelocityGains(Vector3f(_param_mpc_xy_vel_p.get(), _param_mpc_xy_vel_p.get(),
-						   _param_mpc_z_vel_p.get()) * hover_scale,
-					  Vector3f(_param_mpc_xy_vel_i.get(), _param_mpc_xy_vel_i.get(), _param_mpc_z_vel_i.get()) * hover_scale,
-					  Vector3f(_param_mpc_xy_vel_d.get(), _param_mpc_xy_vel_d.get(), _param_mpc_z_vel_d.get()) * hover_scale);
+		_control.setVelocityGains(
+			Vector3f(_param_mpc_xy_vel_p_acc.get(), _param_mpc_xy_vel_p_acc.get(), _param_mpc_z_vel_p_acc.get()),
+			Vector3f(_param_mpc_xy_vel_i_acc.get(), _param_mpc_xy_vel_i_acc.get(), _param_mpc_z_vel_i_acc.get()),
+			Vector3f(_param_mpc_xy_vel_d_acc.get(), _param_mpc_xy_vel_d_acc.get(), _param_mpc_z_vel_d_acc.get()));
 		_control.setVelocityLimits(_param_mpc_xy_vel_max.get(), _param_mpc_z_vel_max_up.get(), _param_mpc_z_vel_max_dn.get());
 		_control.setThrustLimits(_param_mpc_thr_min.get(), _param_mpc_thr_max.get());
 		_control.setTiltLimit(M_DEG_TO_RAD_F * _param_mpc_tiltmax_air.get()); // convert to radians!
@@ -407,7 +405,7 @@ MulticopterPositionControl::parameters_update(bool force)
 		// set trigger time for takeoff delay
 		_takeoff.setSpoolupTime(_param_mpc_spoolup_time.get());
 		_takeoff.setTakeoffRampTime(_param_mpc_tko_ramp_t.get());
-		_takeoff.generateInitialRampValue(_param_mpc_thr_hover.get(), _param_mpc_z_vel_p.get());
+		_takeoff.generateInitialRampValue(_param_mpc_z_vel_p_acc.get());
 
 		if (_wv_controller != nullptr) {
 			_wv_controller->update_parameters();

src/modules/mc_pos_control/mc_pos_control_params.c

@@ -148,34 +148,40 @@ PARAM_DEFINE_FLOAT(MPC_Z_P, 1.0f);
 /**
  * Proportional gain for vertical velocity error
  *
- * @min 0.1
- * @max 0.4
+ * defined as correction acceleration in m/s^2 per m/s velocity error
+ *
+ * @min 2.0
+ * @max 8.0
  * @decimal 2
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_Z_VEL_P, 0.2f);
+PARAM_DEFINE_FLOAT(MPC_Z_VEL_P_ACC, 4.0f);
 
 /**
  * Integral gain for vertical velocity error
  *
+ * defined as correction acceleration in m/s^2 per m velocity integral
+ *
  * Non zero value allows hovering thrust estimation on stabilized or autonomous takeoff.
  *
- * @min 0.01
- * @max 0.1
+ * @min 0.2
+ * @max 2.0
  * @decimal 3
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_Z_VEL_I, 0.1f);
+PARAM_DEFINE_FLOAT(MPC_Z_VEL_I_ACC, 2.0f);
 
 /**
  * Differential gain for vertical velocity error
  *
+ * defined as correction acceleration in m/s^2 per m/s^2 velocity derivative
+ *
  * @min 0.0
- * @max 0.1
+ * @max 2.0
  * @decimal 3
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_Z_VEL_D, 0.0f);
+PARAM_DEFINE_FLOAT(MPC_Z_VEL_D_ACC, 0.0f);
 
 /**
  * Maximum vertical ascent velocity
@@ -215,34 +221,39 @@ PARAM_DEFINE_FLOAT(MPC_XY_P, 0.95f);
 /**
  * Proportional gain for horizontal velocity error
  *
- * @min 0.06
- * @max 0.15
+ * defined as correction acceleration in m/s^2 per m/s velocity error
+ *
+ * @min 1.2
+ * @max 3.0
  * @decimal 2
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_XY_VEL_P, 0.09f);
+PARAM_DEFINE_FLOAT(MPC_XY_VEL_P_ACC, 1.8f);
 
 /**
  * Integral gain for horizontal velocity error
  *
+ * defined as correction acceleration in m/s^2 per m velocity integral
  * Non-zero value allows to eliminate steady state errors in the presence of disturbances like wind.
  *
  * @min 0.0
- * @max 3.0
+ * @max 60.0
  * @decimal 3
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_XY_VEL_I, 0.02f);
+PARAM_DEFINE_FLOAT(MPC_XY_VEL_I_ACC, 0.4f);
 
 /**
  * Differential gain for horizontal velocity error. Small values help reduce fast oscillations. If value is too big oscillations will appear again.
  *
- * @min 0.005
- * @max 0.1
+ * defined as correction acceleration in m/s^2 per m/s^2 velocity derivative
+ *
+ * @min 0.1
+ * @max 2.0
  * @decimal 3
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_XY_VEL_D, 0.01f);
+PARAM_DEFINE_FLOAT(MPC_XY_VEL_D_ACC, 0.2f);
 
 /**
  * Maximum horizontal velocity in mission