Crate featherstone 

featherstone

Featherstone articulated body dynamics solver.

O(n) forward/inverse dynamics for kinematic trees, with LCP contact solving and differentiable smooth contacts. MuJoCo-grade solver quality in a minimal, dependency-light Rust crate.

Algorithms

• ABA — Articulated Body Algorithm: O(n) forward dynamics
• RNEA — Recursive Newton-Euler: O(n) inverse dynamics, gravity compensation
• CRBA — Composite Rigid Body Algorithm: mass matrix computation
• Forward Kinematics — body transforms, velocities, Jacobians, CoM
• GJK/EPA — convex collision detection
• LCP Solver — Projected Gauss-Seidel with warm-starting
• Newton Solver — quadratic-convergence contact solver for stacking
• Smooth Contacts — differentiable contact forces for gradient-based optimization
• Integration — semi-implicit Euler, RK4, Verlet, implicit, explicit

Usage

use featherstone::prelude::*;

Modules

aba

Articulated Body Algorithm (ABA) — O(n) Forward Dynamics

body

Articulated body tree data structure

collider

Collision geometry types for articulated body contact detection.

contact

Contact manifold for articulated body dynamics

contact_jacobian

Contact Jacobians and friction cone constraints

crba

Composite Rigid Body Algorithm (CRBA) — Mass Matrix Computation.

error

Error types for the featherstone crate.

gjk

GJK (Gilbert-Johnson-Keerthi) distance algorithm and EPA (Expanding Polytope Algorithm).

integrator

Time integration methods for articulated body dynamics

joint

Generalized-coordinate joint types for articulated body dynamics

kinematics

Forward kinematics from generalized coordinates

lcp_solver

Projected Gauss-Seidel (PGS) solver for the contact LCP

limits

Joint limit constraints using MuJoCo-style spring-damper barriers

newton_solver

Newton contact solver — quadratic convergence for MuJoCo-grade stacking

prelude

Commonly used types and functions.

rnea

Recursive Newton-Euler Algorithm (RNEA) — O(n) Inverse Dynamics

smooth_contact

Smooth differentiable contact model (MuJoCo-style)

spatial

Spatial vector algebra for articulated body dynamics

urdf_convert

URDF/MJCF to ArticulatedBody conversion