Add rover setpoints and rover example #140

chfriedrich98 · 2025-08-13T13:00:56Z

This PR adds the rover setpoints that were exposed to DDS in PX4/PX4-Autopilot#25074 to the available setpoints.
All the rover setpoints are in their own folder/group to clearly separate them from the regular setpoints as they will have no effect on other vehicle types.

It also adds a mode example for rovers: Rover Velocity Mode.
This manual mode fits between Stabilized and Position mode:
Based on the manual input this mode publishes a RoverVelocitySetpoints and a RoverRateSetpoint.
Unlike Stabilized mode, this mode can utilize closed loop speed control and unlike Position mode, this mode does not requrie a position estimate.

New mode was tested in SITL with the ackermann rover: https://review.px4.io/plot_app?log=b3074d19-c15d-46e4-9bfe-5e505cf668eb

bkueng

Nice.
The setpoint classes do not need to map 1:1 to a PX4 message. They can also have multiple update methods.
Can you design the setpoint types according to different usages, and combine the thrust and yaw accordingly?
You can look at the fixed-wing sp for an example.

Since more vehicle types are being added, can you move the fixedwing and goto setpoint types also into their respective subdirectories?

bkueng · 2025-08-15T06:45:52Z

examples/cpp/modes/rover_velocity/include/mode.hpp

+    const float speed = _manual_control_input->throttle() * kMaxSpeed;
+    _rover_velocity_setpoint->update(speed, NAN, NAN);
+
+    // Rate is not updated through the setpoint type to avoid overriding vehicle control mode.
+    const float yaw_rate = _manual_control_input->roll() * kMaxYawRate * M_PI / 180.f;
+    px4_msgs::msg::RoverRateSetpoint sp{};
+    sp.yaw_rate_setpoint = yaw_rate;
+    sp.timestamp = 0; // Let PX4 set the timestamp
+    _rover_rate_setpoint_pub->publish(sp);


If it is possible to combine them I would rather do that in the RoverVelocitySetpointType,
e.g. add a method update(velocity, yaw_rate). Then it's clear how it can be used.

I combined the setpoints in 78a7fe7. Not quite like you suggested, see #140 (comment) for reasoning.

bkueng · 2025-08-15T06:47:05Z

px4_ros2_cpp/CMakeLists.txt

@@ -40,6 +40,12 @@ set(HEADER_FILES
        include/px4_ros2/control/setpoint_types/experimental/attitude.hpp
        include/px4_ros2/control/setpoint_types/experimental/rates.hpp
        include/px4_ros2/control/setpoint_types/experimental/trajectory.hpp
+        include/px4_ros2/control/setpoint_types/rover/rover_position.hpp


I'd remove the redundant prefix

Suggested change

include/px4_ros2/control/setpoint_types/rover/rover_position.hpp

include/px4_ros2/control/setpoint_types/rover/position.hpp

Implemented in 78a7fe7

bkueng · 2025-08-15T06:48:03Z

px4_ros2_cpp/include/px4_ros2/control/setpoint_types/rover/rover_attitude.hpp

+  ~RoverAttitudeSetpointType() override = default;
+
+  Configuration getConfiguration() override;
+  float desiredUpdateRateHz() override {return 100.f;}


30 is probably enough for all of them (?)

Reduced it to 30 in e9ef220

bkueng · 2025-08-15T06:49:21Z

px4_ros2_cpp/include/px4_ros2/control/setpoint_types/rover/rover_attitude.hpp

+  /**
+   * @brief Send a rover attitude setpoint to the flight controller.
+   *
+   * @param yaw_setpoint [rad] [@range -inf, inf] [@frame NED] Yaw setpoint


Can you remove the @range and expand them? Doxygen does not like these.

Changed descriptions in d2638ff

bkueng · 2025-08-15T06:49:49Z

px4_ros2_cpp/include/px4_ros2/control/setpoint_types/rover/rover_attitude.hpp

+   *
+   * @param yaw_setpoint [rad] [@range -inf, inf] [@frame NED] Yaw setpoint
+  */
+  void update(float yaw_setpoint);


How is thrust controlled then?

Combined the setpoints in 78a7fe7.

bkueng · 2025-08-15T06:51:43Z

px4_ros2_cpp/include/px4_ros2/control/setpoint_types/rover/rover_position.hpp

+   *
+   * @param position_ned [m] [@range -inf, inf] [@frame NED] Target position
+   * @param start_ned [m] [@range -inf, inf] [@frame NED] [@invalid NaN Defaults to vehicle position] Start position which specifies a line for the rover to track
+   * @param cruising_speed [m/s] [@range 0, inf] [@invalid NaN Defaults to maximum speed] Cruising speed


Can you use std::optional instead of NaN for optional arguments?

Implemented in d2638ff

chfriedrich98 · 2025-08-20T12:53:34Z

@bkueng Thank you for the review!

The setpoint classes do not need to map 1:1 to a PX4 message. They can also have multiple update methods.
Can you design the setpoint types according to different usages, and combine the thrust and yaw accordingly?

This actually prompted me to have another look at the rover setpoints on PX4 side and I made some adjustments s.t. it is easier to understand which combination of setpoints are valid (for reference PX4/PX4-Autopilot#25447).
TLDR: The rover modules use a hierarchical structure to propogate setpoints (i.e. the "highest" valid setpoint will override the rest):

With this hierarchy there are now clear rules for accessing rover setpoints through the API:
Publishing a position setpoint will override all other setpoints and for all other cases we require the following:
One of the setpoints on the "left" (speed or throttle) and one of the setpoints on the "right" (attitude, rate or steering) have to be specified. All combinations of "left" and "right" setpoints are valid.

In 78a7fe7 I exposed all of these valid combinations as their own setpoint.
The reason I did not combine them by having multiple update methods is because they all have different configs.
(Is there a way to change configs when different update functions are called?)

lesha198a · 2025-08-20T13:22:59Z

examples/cpp/modes/rover_velocity/CMakeLists.txt

@@ -0,0 +1,32 @@
+cmake_minimum_required(VERSION 3.5)
+project(rover_velocity_mode_cpp)


it's not an issue but I just saw difference in built target names) so maybe it's gonna be better:
project(example_rover_velocity_mode_cpp)

Makes sense, changed in 53fbe9c

chfriedrich98 · 2025-08-20T14:18:33Z

CI checks seem to fail because they are not using the latest version of px4_msgs which includes the message change RoverVelocitySetpoint $$\rightarrow$$ RoverSpeedSetpoint. 🤔

bkueng

The reason I did not combine them by having multiple update methods is because they all have different configs.
(Is there a way to change configs when different update functions are called?)

It makes sense as you have it now. Different configs require different setpoint types (although you could create a class that combines multiple), as different configs (i.e. active controllers) are typically sufficiently different in their uses.

CI checks seem to fail because they are not using the latest version of px4_msgs which includes the message change

The message sync takes a while, but now they should be available.

Can you later on also add some docs to https://docs.px4.io/main/en/ros2/px4_ros2_control_interface.html#setpoint-types?

examples/cpp/modes/rover_velocity/include/mode.hpp

bkueng · 2025-08-22T08:38:27Z

px4_ros2_cpp/include/px4_ros2/components/message_compatibility_check.hpp

+  {"fmu/in/rover_attitude_setpoint"}, \
+  {"fmu/in/rover_position_setpoint"}, \
+  {"fmu/in/rover_rate_setpoint"}, \
+  {"fmu/in/rover_speed_setpoint"}, \
+  {"fmu/in/rover_steering_setpoint"}, \
+  {"fmu/in/rover_throttle_setpoint"}, \


How stable do you think these messages are?
They should (eventually) be versioned by moving them under versioned and adding uint32 MESSAGE_VERSION = 0 (https://github.com/PX4/PX4-Autopilot/blob/main/msg/versioned/ActuatorMotors.msg#L6).
If you expect changes, I'd move the setpoint classes here under experimental

We decided against adding the rover setpoints to versioned because there is still the possiblity that we extend them to all ground vehicles (PX4/PX4-Autopilot#25074 (comment)).
Added them to experimental in 91b79f7 as you suggested.

bkueng · 2025-08-22T08:42:46Z

px4_ros2_cpp/include/px4_ros2/control/setpoint_types/rover/position.hpp

+   * @brief Send a rover position setpoint to the flight controller.
+   *
+   * @param position_ned [m] Target position in NED frame. Takes values in [-inf, inf].
+   * @param start_ned [m] Start position which specifies a line for the rover to track (Optional, defaults to vehicle position). Takes values in [-inf, inf].


This can also use std::optional if it's optional

implemented in f68797f

px4_ros2_cpp/include/px4_ros2/control/setpoint_types/rover/position.hpp

Co-authored-by: Beat Küng <beat-kueng@gmx.net>

chfriedrich98 self-assigned this Aug 13, 2025

chfriedrich98 force-pushed the pr-rover_setpoints branch 2 times, most recently from a8cab35 to f92c1eb Compare August 13, 2025 13:22

chfriedrich98 added 2 commits August 13, 2025 16:14

add rover setpoints

f3dbf42

add rover manual velocity mode

9a077da

chfriedrich98 force-pushed the pr-rover_setpoints branch from f92c1eb to 9a077da Compare August 13, 2025 14:14

chfriedrich98 marked this pull request as ready for review August 14, 2025 07:20

chfriedrich98 requested review from bkueng and mahima-yoga August 14, 2025 07:23

bkueng reviewed Aug 15, 2025

View reviewed changes

expose valid combinations of rover setpoints

78a7fe7

lesha198a reviewed Aug 20, 2025

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chfriedrich98 added 5 commits August 20, 2025 15:42

use std:optional instead of NAN

d2638ff

reduce rover setpoints update rate to 30

e9ef220

add example prefix to rover velocity mode

53fbe9c

fix lint issues

50050ea

fix lint issues 2

5db92b5

chfriedrich98 requested a review from bkueng August 20, 2025 14:18

bkueng reviewed Aug 22, 2025

View reviewed changes

chfriedrich98 and others added 3 commits August 22, 2025 12:22

Apply suggestions from code review

214c5fb

Co-authored-by: Beat Küng <beat-kueng@gmx.net>

make start position optional

f68797f

move rover setpoints to experimental

91b79f7

chfriedrich98 requested a review from bkueng August 22, 2025 11:19

	include/px4_ros2/control/setpoint_types/rover/rover_position.hpp
	include/px4_ros2/control/setpoint_types/rover/position.hpp

		@@ -0,0 +1,32 @@
		cmake_minimum_required(VERSION 3.5)
		project(rover_velocity_mode_cpp)

Add rover setpoints and rover example #140

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Add rover setpoints and rover example #140

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chfriedrich98 commented Aug 13, 2025 •

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