MC Jerk-limited Type Trajectory
Last updated
Last updated
The Jerk-limited trajectory type provides smooth motion in response to user stick input or mission changes (e.g.: for filming, mapping, cargo). It generates symmetric smooth S-curves where the jerk and acceleration limits are always guaranteed.
This trajectory type is always enabled in . To enable it in set the parameter: .
:::note The jerk-limited type is not used by default in position mode. It may not be suitable for vehicles/use-cases that require a faster response - e.g. racer quads. :::
The graph below shows a typical jerk-limited profile with the following constraints:
jMax: maximum jerk
a0: initial acceleration
aMax: maximum acceleration
a3: final acceleration (always 0)
v0: initial velocity
vRef: desired velocity
The constraints jMax, aMax are configurable by the user via parameters and can be different in manual position control and auto mode.
The resulting velocity profile is often called "S-Curve".
XY-plane:
Z-axis:
XY-plane:
Z-axis:
Distance to velocity gains when close to a waypoint:
In manual position mode, the sticks are mapped to velocity where a full XY-stick deflection corresponds to and a full Z-stick deflection corresponds to (upward motion) or (downward motion).
jMax:
aMax:
jMax:
aMax (upward motion):
aMax (downward motion):
In auto mode, the desired velocity is but this value is automatically adjusted depending on the distance to the next waypoint, the maximum possible velocity in the waypoint and the maximum desired acceleration and jerk. The vertical speed is defined by (upward motion) and (downward motion).
jMax:
aMax:
jMax:
aMax (upward motion):
aMax (downward motion):
