Vehicle Attitude

Read vehicle_odometry uORB topic and obtain attitude measurements

Add-On Required: This feature requires the UAV Toolbox Support Package for PX4 Autopilots add-on.

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Libraries:
UAV Toolbox Support Package for PX4 Autopilots / PX4 Sensor Blocks

Description

The Vehicle Attitude block reads the vehicle_odometry uORB topic and outputs the attitude measurements from the Pixhawk^® hardware. The block outputs the vehicle attitude in both roll, pitch, and yaw, and quaternion (NED) form.

On each simulation step, the block checks if a new message is available on the vehicle_odometry topic. If a new message is available, the block retrieves the message and outputs it, and the timestamp is updated. If a new message is not available, the block outputs the last updated uORB message and the timestamp is not updated. If a message has not been received since the start of the simulation, the outputs are zeroes.

During Normal mode simulation, the block outputs zeroes.

During Connected I/O simulation, this block reads data from the peripherals of the hardware.

Ports

Output

Status — Status of the received uORB data

0 | 1

The Status output indicates if the vehicle_odometry uORB message was received during a previous time step or not. A value of 0 indicates that the uORB data at the outputs is the latest, and a value of 1 indicates that the uORB data was not updated during the previous time step.

This output can be used to trigger subsystems for processing new messages received in the uORB network.

Data Types: Boolean

Roll rate — Bias corrected angular velocity about x-axis

scalar | rad/s

The bias corrected angular velocity about x-axis, as read from the vehicle_odometry uORB topic.

Data Types: single

Pitch rate — Bias corrected angular velocity about y-axis

scalar | rad/s

The bias corrected angular velocity about y-axis, as read from the vehicle_odometry uORB topic.

Data Types: single

Yaw rate — Bias corrected angular velocity about z-axis

scalar | rad/s

The bias corrected angular velocity about z-axis, as read from the vehicle_odometry uORB topic.

Data Types: single

Quaternion — Attitude of the vehicle on which the PX4 flight controller is mounted, in quaternion form

1-by-4 array

The attitude of the vehicle on which the PX4 flight controller is mounted, in quaternion form, as read from the vehicle_odometry uORB topic.

Data Types: single

Timestamp — Timestamp of the received uORB data

time in microseconds

Represents the time (since the PX4^® system start) when the vehicle_odometry topic was last updated.

Data Types: double

Parameters

Main tab

Roll — Enable roll value as one of the outputs

off (default) | on

Pitch — Enable pitch value as one of the outputs

off (default) | on

Yaw — Enable yaw value as one of the outputs

off (default) | on

Quaternion — Enable quaternion value as one of the outputs

on (default) | off

Timestamp — Enable timestamp value as one of the outputs

off (default) | on

Sample time — Interval at which the block reads values

1/250 (default) | any non-negative value that is a multiple of 1/250 | -1

Enter the time interval at which the block reads values from the uORB network.

When you set this parameter to -1, Simulink^® determines the best sample time for the block based on the block context within the model.

Advanced Tab

Wait until data received — Wait until requested data is available

off (default) | on

• When you select this option, the read operation runs in Blocking Mode. The read operation is blocked while waiting for the requested data to be available. When the data is available, the block outputs the selected values, and the Status port is set to 0.

  The board waits for the message in Blocking Mode for the time mentioned in the Timeout in seconds. If the data is not received before the timeout, then the Status port outputs 1 and the block outputs the last received value.

  A task overrun occurs if the target hardware is still waiting for the data to be available when the next read operation is scheduled to begin.

  To fix overruns, increase the time step by using the Sample time parameter.

• When you clear this option, the read operation runs in Non-Blocking Mode. In this mode, the block does not wait for the requested data to be available.

Timeout in seconds — Time to wait until the data is received

1e-3 (default) | (0, 2^32/1000]

Specify the amount of time that the block waits for the data during each time step, if the Wait until data received parameter is selected. If timeout occurs, the read operation is aborted.

Dependencies

This parameter appears only when you select the Wait until data received parameter.

Version History

Introduced in R2018b