Add getters for joint velocity, effort, and position limits

[naitikpahwa18]

🎉 New feature

Closes #2664

Summary

This PR adds getter APIs for retrieving joint velocity, effort, and position limits.

gz::sim::Joint already provides setter methods for velocity limits, but
no corresponding getter. This change adds Joint::VelocityLimits(), which
reads the limit from the existing components::JointAxis state
(sdf::JointAxis::MaxVelocity), including support for multi-axis joints.

In addition, this PR also introduces getter methods for effort and position
limits for completeness and API symmetry with the existing setters.

Test it

ctest -R Joint_TEST

Checklist

• Signed all commits for DCO
• Added tests

[Copilot]

Pull request overview

This PR adds a getter method VelocityLimits() to the gz::sim::Joint class to retrieve joint velocity limits from existing component state, complementing the existing SetVelocityLimits() setter method.

Changes:

• Added Joint::VelocityLimits() public API method that returns velocity limits as std::optional<std::vector<gz::math::Vector2d>>
• Implementation reads from components::JointAxis and components::JointAxis2 components and converts MaxVelocity() values into symmetric limit ranges
• Added unit test covering multi-axis joint case

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
include/gz/sim/Joint.hh	Added public API declaration with comprehensive documentation for VelocityLimits() getter method
src/Joint.cc	Implemented VelocityLimits() method that reads from JointAxis components and constructs symmetric velocity limits
src/Joint_TEST.cc	Added VelocityLimitsMultiAxis test case to verify multi-axis joint limit retrieval

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[arjo129]

Thanks for iterating and re-opening a new PR. I think we should change this to just return a std::vector<double>. In the future if SDF supports asymetric max and min values we can add a function for retrieving min velocity.

[arjo129]

Thanks for the iteration, one last small knit. Lets put Max somewhere in the function name.

[arjo129]

CI is complaining about line length, also would be worth updating the python bindings here: https://github.com/gazebosim/gz-sim/blob/gz-sim10/python/src/gz/sim/Joint.cc

If you cant update the python bindings open a ticket on the issue tracker so we remember to do it at some point.

[naitikpahwa18]

I’ve applied the requested changes (API rename to MaxVelocityLimits, updated Python bindings and fix line length).

[naitikpahwa18]

@arjo129 I’m seeing multiple CI failures related to Joint_TEST. Could you please advise if you’d like any changes from my side?

[arjo129]

Can you fix the style complaints?
https://github.com/gazebosim/gz-sim/actions/runs/21163230348/job/60866147875#step:5:1

I'm guessing the issues arise from bazel as those are the runners that are failing to compile.

[naitikpahwa18]

Fixed style issues and added missing JointAxis include in Joint_TEST. CI is re-running.

[naitikpahwa18]

Hi @arjo129, just a quick reminder to check this out when you get a chance. Thanks!

[arjo129]

Thanks for the iteration

[naitikpahwa18]

Hi @arjo129, I’ve added effort and position limit getters following the MaxVelocityLimits pattern, with unit tests included. This should complete the current issue. Let me know if any changes are needed.

[arjo129]

Thanks for the iteration on this PR.

[naitikpahwa18]

Hi @arjo129, just a quick reminder to check this out when you get a chance. Thanks!