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 0% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.08%. Comparing base (ab5ce0c) to head (0bddc84).

Files with missing lines	Patch %	Lines
...iff_drive_controller/src/diff_drive_controller.cpp	0.00%	5 Missing and 1 partial ⚠️
...er/include/diff_drive_controller/speed_limiter.hpp	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2293      +/-   ##
==========================================
- Coverage   85.13%   85.08%   -0.05%     
==========================================
  Files         154      154              
  Lines       15417    15425       +8     
  Branches     1334     1335       +1     
==========================================
  Hits        13125    13125              
- Misses       1800     1807       +7     
- Partials      492      493       +1     

Flag	Coverage Δ
unittests	85.08% <0.00%> (-0.05%)	⬇️

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	66.66% <0.00%> (-33.34%)	⬇️
...iff_drive_controller/src/diff_drive_controller.cpp	78.71% <0.00%> (-1.41%)	⬇️

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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 😅