Add acceleration stick mapping for position mode

src/modules/mc_pos_control/MulticopterPositionControl.cpp

@@ -597,6 +597,10 @@ void MulticopterPositionControl::start_flight_task()
 			error =  _flight_tasks.switchTask(FlightTaskIndex::ManualPositionSmoothVel);
 			break;
 
+		case 4:
+			error =  _flight_tasks.switchTask(FlightTaskIndex::ManualAcceleration);
+			break;
+
 		default:
 			error =  _flight_tasks.switchTask(FlightTaskIndex::ManualPosition);
 			break;

src/modules/mc_pos_control/mc_pos_control_params.c

@@ -463,7 +463,10 @@ PARAM_DEFINE_FLOAT(MPC_VELD_LP, 5.0f);
 /**
  * Maximum horizontal acceleration for auto mode and for manual mode
  *
- * Maximum deceleration for MPC_POS_MODE 1. Maximum acceleration and deceleration for MPC_POS_MODE 3.
+ * MPC_POS_MODE
+ * 1 just deceleration
+ * 3 acceleration and deceleration
+ * 4 just acceleration
  *
  * @unit m/s^2
  * @min 2.0
@@ -536,7 +539,7 @@ PARAM_DEFINE_FLOAT(MPC_ACC_DOWN_MAX, 3.0f);
  *
  * Setting this to the maximum value essentially disables the limit.
  *
- * Note: This is only used when MPC_POS_MODE is set to a smoothing mode 1 or 3.
+ * Note: This is only used when MPC_POS_MODE is set to a smoothing mode 1, 3 or 4.
  *
  * @unit m/s^3
  * @min 0.5
@@ -727,13 +730,15 @@ PARAM_DEFINE_FLOAT(MPC_TKO_RAMP_T, 3.0f);
  * 1 Smooth position control with maximum acceleration and jerk limits based on slew-rates.
  * 3 Smooth position control with maximum acceleration and jerk limits based on
  *   jerk optimized trajectory generator (different algorithm than 1).
+ * 4 Smooth position control where sticks map to acceleration and there's a virtual brake drag
  *
  * @value 0 Simple position control
  * @value 1 Smooth position control
  * @value 3 Smooth position control (Jerk optimized)
+ * @value 4 Acceleration based input
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_INT32(MPC_POS_MODE, 3);
+PARAM_DEFINE_INT32(MPC_POS_MODE, 4);
 
 /**
  * Enforced delay between arming and takeoff