diff_drive_controller: set parameters as read_only

[kamal2730]

Add read_only: true to all 36 parameters in diff_drive_controller for consistency with other drive controllers.
Fixes #1696

Description

Right now I added read_only: true for all params because currently, the controller does not support runtime parameter updates for SpeedLimiter-related parameters. This would require adding try_update_params() to the RT loop and implementing a set_params() method in the SpeedLimiter class. If needed, I will address this in a follow-up PR.

Fixes #1696

Is this user-facing behavior change?

NO

Did you use Generative AI?

No

Additional Information

TODOs

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[christophfroehlich]

Please evaluate which parameters make sense to be reconfigured at runtime, see my comment here
#2074 (review)

[kamal2730]

I evaluated which parameters make sense to be reconfigured at runtime and identified 19 parameters that can be made dynamic:
Member variable updates:

• cmd_vel_timeout

Direct from params_ (auto-updates):

• publish_limited_velocity
• enable_odom_tf'

SpeedLimiter set_params() updates:

• linear.x.max_velocity
• linear.x.min_velocity
• linear.x.max_acceleration
• linear.x.max_deceleration
• linear.x.max_acceleration_reverse
• linear.x.max_deceleration_reverse
• linear.x.max_jerk
• linear.x.min_jerk
• angular.z.max_velocity
• angular.z.min_velocity
• angular.z.max_acceleration
• angular.z.max_deceleration
• angular.z.max_acceleration_reverse
• angular.z.max_deceleration_reverse
• angular.z.max_jerk
• angular.z.min_jerk

Implementation Plan

I will handle the runtime updates in update_and_write_commands() by:

1. Adding if (param_listener_->try_update_params(params_)) check
2. Updating cmd_vel_timeout member variable
3. Calling set_params() on SpeedLimiter objects for velocity/acceleration/jerk limits
4. publish_limited_velocity and enable_odom_tf auto-update with params_
   Does this approach look good to you?

[christophfroehlich]

Sounds good. Only, I'm not sure about cmd_vel_timeout, but both options are fine for me.

[kamal2730]

@christophfroehlich Added parameter handling for runtime updates. Could you review?

[codecov]

Codecov Report

❌ Patch coverage is 92.45283% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.01%. Comparing base (27ea539) to head (ba1b901).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
...iff_drive_controller/src/diff_drive_controller.cpp	50.00%	2 Missing and 1 partial ⚠️
...ive_controller/test/test_diff_drive_controller.cpp	97.77%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2293      +/-   ##
==========================================
+ Coverage   84.99%   85.01%   +0.02%     
==========================================
  Files         145      145              
  Lines       15186    15234      +48     
  Branches     1331     1336       +5     
==========================================
+ Hits        12907    12951      +44     
- Misses       1789     1791       +2     
- Partials      490      492       +2     

Flag	Coverage Δ
unittests	85.01% <92.45%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...er/include/diff_drive_controller/speed_limiter.hpp	100.00% <100.00%> (ø)
...ive_controller/test/test_diff_drive_controller.cpp	95.07% <97.77%> (+0.31%)	⬆️
...iff_drive_controller/src/diff_drive_controller.cpp	79.59% <50.00%> (-0.53%)	⬇️

... and 3 files with indirect coverage changes

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[christophfroehlich]

looks fine for me, but could you please add a test for the parameter updates at runtime? have a look at existing tests with specified limits, copy it, and extend it with another update call with changed limits.

[kamal2730]

Sure, even I was thinking the same 😅

[kamal2730]

@christophfroehlich Added test for runtime parameter updates of speed limiter. Could you please review?

[christophfroehlich]

Thank you! LGTM, I only have 2 nitpicks about readability.

[christophfroehlich]

Suggested change

	const double time_dec = 1.0 / 4.0;
	const double time_dec = 1.0 / std::abs(max_deceleration);

[kamal2730]

Hello @christophfroehlich , I’ve addressed the requested changes. Ready for review!

[christophfroehlich]

perfect, thank you!