v4.2.0

This release adds the ManipulabilityTask contributed by @danielsanjosepro 👍

It also corrects the G1 humanoid example with a fix provided by @nmarticorena.

Added

• Task: Add ManipulabilityTask to maximize manipulability of a manipulator (thanks to @danielsanjosepro)
• examples: Add Panda manipulability comparison example
• examples: Add planar 2-DOF manipulability example
• examples: Visualize current and designed center-of-mass positions in Humanoid G1 example (thanks to @nmarticorena)

Fixed

• examples: Fix numerical behavior of Humanoid G1 example (thanks to @nmarticorena)

v4.1.0

This release adds Viser visualization and an example using it to tune the tasks of a 7-DoF manipulator, contributed by @danielsanjosepro 👍

2026-02-15.17-48-35.mp4

Added

• Task: Add orientation_cost property to the frame task (thanks to @danielsanjosepro)
• Task: Add position_cost property to the frame task (thanks to @danielsanjosepro)
• examples: Add an example of a panda arm tracking an interactive target in Viser visualizer (thanks to @danielsanjosepro)
• visualization: Add start_viser_visualizer function for the Viser visualizer (thanks to @danielsanjosepro)

Changed

• Bump minimum Python version to 3.10

v4.0.0

This release adds the FloatingBaseVelocityLimit contributed by @Soontosh 👍

Its breaking change is an update to the Limits API: limits now work on full configuration instances (rather than configuration vectors).

Added

• limits: Allow floating base velocity limits with FloatingBaseVelocityLimit to plug into configurations to automatically clamp base twists (thanks to @Soontosh)

Changed

• Breaking: Limit.compute_qp_inequalities functions now take a full configuration as argument rather than a configuration vector

Fixed

• CICD: Update CoM unit test that has started failing on macOS runners

v3.5.0

This release fixes the acceleration limit, thanks to @bwingo47 for pointing out the former issue 👍 It also annotates example so that we can uv run them directly.

Added

• examples: Add example with a sparse QP solver, suppressing matrix conversion warnings
• examples: Add uv script dependencies to all examples

Changed

• CICD: Update Pylint configuration

Fixed

• Correct changelog version comparison links
• Limit: Fix braking-limit formula in acceleration limit
• docs: Fix typos in the acceleration limit documentation

v3.4.0

This release adds the JointVelocityTask whose aim is to track a reference joint-velocity vector via $\arg\min_v \Vert v_{ref} - v \Vert^2$. This task can be used, for instance, if a reference velocity is computed by other means (optimal control, reinforcement-learned policy, ...), and the differential IK acts as a constraint-enforcing filter. An example illustrates this with a Unitree Z1 tracking a trajectory that would violate joint limits:

arm_z1_cropped.mp4

(In the example, joint limits don't prevent self-collisions when the arm is folded on itself.)

Added

• Task: JointVelocityTask for tracking a reference joint-velocity trajectory

Fixed

• Save problem instance in NoSolutionFound exception

Removed

• Remove unused attribute of SelfCollisionBarrier

v3.3.0

This version adds (1) a constraints argument to solve_ik, to enforce tasks as QP equality constraints rather than in the objective function, and (2) the omniwheel task, which is like a rolling task but allows lateral motion.

Note that, internally, exceptions have been grouped into the pink.exceptions submodule. We don't count this as an API-breaking change, although strictly speaking it is 😊, as the expected way to handle Pink exceptions is to catch PinkError.

Thanks to @jorisv for contributing to this release 👍

Added

• CICD: Unit test fixture for the rolling task
• CICD: Unit test fixture for the omniwheel task
• Introduce constraints to enforce tasks as QP equality constraints
• Task: Add missing task __repr__ functions
• Task: Omniwheel task, like a rolling task but allowing lateral motion

Changed

• CICD: Switch to Pixi for code coverage, documentation, linting and testing
• Move pink.barriers.exceptions to pink.exceptions
• Move pink.tasks.exceptions to pink.exceptions
• Task: Make __repr__ of base class abstract to ensure tasks define their own
• docs: Refactor Tasks page and update references
• examples: Update installation hints when example dependencies are missing

Fixed

• CICD: Improve Pixi configuration (thanks to @jorisv)
• Task: Fix damping task when the robot model has a mobile root joint
• Task: Report LM damping in CoM task representation

v3.2.0

This release introduces the NoSolutionFound exception (previously an AssertionError), and makes a stricter check that the QP solver reports successfully converging to a solution. It is still possible to catch cases where the solver converged (but not to a solution) as follows:

try:
    velocity = solve_ik(configuration, tasks, dt, solver=solver)
except NoSolutionFound as exn:
    if exn.results.x is not None:  # QP solver converged but not to a solution
        velocity = exn.results.x
    raise exn

This release also removes an unrequired dependency on quadprog. This solver is still great for IK, but we cannot distribute it with Pink (permissive license: Apache-2.0) as it is licensed under the GPL-2.0. Feel free to install and use it on your own!

Thanks to @ashwinvkNV and @peterd-NV for helping address this licensing issue 👍

Added

• Add NoSolutionFound exception
• Add open keyword argument to start_meshcat_visualizer
• examples: Detail that quadprog works best on Stretch examples
• examples: Installation instruction for loop-rate-limiters
• examples: Switch to DAQP solvers in examples where it works well
• examples: Switch to ProxQP on JVRC-1 example
• examples: Switch to ProxQP on one-dof configuration limit example

Changed

• CICD: Switch from tox to Anaconda environments
• CICD: Update QP solvers used in unit tests
• CICD: Update checkout action to v4
• Raise custom NoSolutionFound rather than AssertionError in solve_ik
• Update supported Python versions

Fixed

• CICD: Update unit test for self-collision barrier

Removed

• Remove dependency on quadprog (thanks to @peterd-NV)

v3.1.0

This release adds the RollingTask for rolling without slipping. Here is an example:

• Wheeled biped: Upkie rolling without slipping

upkie_rolling_without_slipping.mp4

Added

• Example: Upkie rolling without slipping on a horizontal floor
• Task: RollingTask for rolling without slipping on a plane

Changed

• Rename "end-effector to target" example to "inverse kinematics UR10"
• Update icon of documentation website

Fixed

• Update documentation Sphinx and theme versions
• Fix Jacobian of SelfCollisionBarrier for floating-base robots

v3.0.0

This major release adds Control Barrier Functions developed by @domrachev03 and @simeon-ned 👍 Examples of what we can do with barriers include:

• Arm: UR5: with joints and end effector limits
• Humanoid: G1: G1 humanoid squatting via a CoM task
• Quadruped: Go2: Go 2 squatting with floating base position limits
• Dual Arms: Yumi: self-collision avoidance with spheres
• Dual Arms: Iiwa: whole-body self-collision avoidance

Screencast.from.06-25-2024.01.20.45.PM.webm

Another API-breaking change to the library is that limits are now optional and can be extended (for instance with the new acceleration limit) or disabled. New limits and tasks include:

• Limit: AccelerationLimit
• Task: ComTask for center-of-mass tracking (thanks to @simeon-ned)
• Task: LowAccelerationTask for smoother velocities.

Check out the full changelog below for other changes and fixes. May the Motion be with you!

Added

• Breaking: Updated the logic for handling the joint limits:
  • Add a limits argument to build_ik and solve_ik
  • The check_limits method now includes an optional safety_break argument to control whether execution should stop on exception.
  • The solve_ik function now includes the safety_break that is forwarded to check_limits.
• Control Barrier Functions, namely: (thanks to @domrachev03 and @simeon-ned)
  • Abstract Barrier Barrier
  • Frame Position Barrier PositionBarrier
  • Body Spherical Barrier BodySphericalBarrier
  • Whole-body Self-Collision Avoidance Barrier SelfCollisionBarrier
• Example: UR5 manipulator and GO2 quadruped robot with PositionBarrier
• Example: YUMI two-armed manipulator with BodySphericalBarrier
• Example: G1 humanoid squatting through regulating CoM.
• Limit: AccelerationLimit
• Task: ComTask for center-of-mass tracking (thanks to @simeon-ned)
• Task: LowAccelerationTask for smoother velocities.

Changed

• Breaking: remove lm_damping parameter from DampingTask where it wasn't used
• CICD: Update ruff to 0.4.3
• Configuration accepts list of Control Barrier Functions
• DampingTask: Simplify implementation
• Update to Pinocchio 3 with 2.7 backward compatibility

Fixed

• PostureTask: Match implementation and documentation formula
• Fix broken documentation links

Removed

• CICD: Disable macOS checks until upstream PyPI package is fixed

v2.1.0

This release adds the RelativeFrameTask developed with @ymontmarin 👍 This new task is a generalization of the frame task that accepts targets with respect to any robot frame. For example:

stretch_examples.mp4

• Left: relative frame task (stretch_relative_target.py example)
• Right: frame task (stretch_world_target.py example)

This release also brings a few quality-of-use improvements to configurations and costs.

Added

• Function get_transform in the Configuration class
• Task: relative frame task, where target is w.r.t another robot frame

Changed

• Configuration: update function now accepts a configuration vector argument
• Costs: setting cost in relative frame task now accepts plain float