Rename params, add transitional support

src/modules/mc_pos_control/mc_pos_control_main.cpp

@@ -442,7 +442,15 @@ MulticopterPositionControl::MulticopterPositionControl() :
 	_params_handles.z_vel_i		= param_find("MPC_Z_VEL_I");
 	_params_handles.z_vel_d		= param_find("MPC_Z_VEL_D");
 	_params_handles.z_vel_max_up	= param_find("MPC_Z_VEL_MAX_UP");
-	_params_handles.z_vel_max_down	= param_find("MPC_Z_VEL_MAX_DOWN");
+	_params_handles.z_vel_max_down	= param_find("MPC_Z_VEL_MAX");
+
+	// transitional support: Copy param values from max to down
+	// param so that max param can be renamed in 1-2 releases
+	// (currently at 1.3.0)
+	float p;
+	param_get(param_find("MPC_Z_VEL_MAX"), &p);
+	param_set(param_find("MPC_Z_VEL_MAX_DN"), &p);
+
 	_params_handles.z_ff		= param_find("MPC_Z_FF");
 	_params_handles.xy_p		= param_find("MPC_XY_P");
 	_params_handles.xy_vel_p	= param_find("MPC_XY_VEL_P");

src/modules/mc_pos_control/mc_pos_control_params.c

@@ -189,12 +189,12 @@ PARAM_DEFINE_FLOAT(MPC_Z_VEL_I, 0.02f);
 PARAM_DEFINE_FLOAT(MPC_Z_VEL_D, 0.0f);
 
 /**
- * Maximum vertical velocity
+ * Maximum vertical ascent velocity
  *
  * Maximum vertical velocity in AUTO mode and endpoint for stabilized modes (ALTCTRL, POSCTRL).
  *
  * @unit m/s
- * @min 0.0
+ * @min 0.5
  * @max 8.0
  * @decimal 1
  * @group Multicopter Position Control
@@ -202,16 +202,26 @@ PARAM_DEFINE_FLOAT(MPC_Z_VEL_D, 0.0f);
 PARAM_DEFINE_FLOAT(MPC_Z_VEL_MAX_UP, 3.0f);
 
 /**
- * Maximum vertical velocity in positive z direction (descending)
+ * Maximum vertical descent velocity
  *
  * Maximum vertical velocity in AUTO mode and endpoint for stabilized modes (ALTCTRL, POSCTRL).
  *
  * @unit m/s
- * @min 0.0
- * @max 8.0
+ * @min 0.5
+ * @max 4.0
+ * @group Multicopter Position Control
+ */
+PARAM_DEFINE_FLOAT(MPC_Z_VEL_MAX, 1.0f);
+
+/**
+ * Transitional support, do not change / use
+ *
+ * @unit m/s
+ * @min 0.5
+ * @max 4.0
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_Z_VEL_MAX_DOWN, 1.0f);
+PARAM_DEFINE_FLOAT(MPC_Z_VEL_MAX_DN, 1.0f);
 
 /**
  * Vertical velocity feed forward