Module model 

Kinematics and dynamics of the arm, mirroring libfranka’s franka::Model.

Model is a port of franka::Model (include/franka/model.h, src/model.cpp); it is a thin dispatch layer over a RobotModelBackend, the equivalent of libfranka’s franka::RobotModelBase. The default backend is native_backend::NativeBackend, a serial-chain implementation that reproduces libfranka’s Pinocchio-based franka::RobotModel bit-for-bit within 1e-9 (kinematics) and 1e-6 (dynamics).

Matrix layouts

• 4x4 poses are vectorised column-major ([f64; 16]).
• Jacobians are 6x7 column-major ([f64; 42]); within a column the rows are the linear parts vx, vy, vz first and the angular parts wx, wy, wz second. This is Pinocchio’s Motion layout, which is what libfranka copies out of Eigen verbatim.
• The mass matrix is 7x7 column-major ([f64; 49]); it is symmetric.

Example

use franka::model::{Frame, Model};
use franka::robot_state::RobotState;

let urdf = std::fs::read_to_string("fr3.urdf").unwrap();
let model = Model::from_urdf(&urdf).unwrap();
let state = RobotState::default();
let o_t_ee = model.pose(Frame::EndEffector, &state);
let gravity = model.gravity(&state);

Re-exports

pub use model_library::load_from_robot;

pub use native_backend::NativeBackend;

Modules

model_library

Downloading and loading the FCI v5 (Franka Emika Robot, FER) model library.

native_backend

Native serial-chain rigid-body backend.

Structs

Model

Poses of the joints and dynamic properties of the robot.

Enums

Frame

The seven joints, the flange, the end effector and the stiffness frame.

Constants

DEFAULT_GRAVITY_EARTH

Earth’s gravity used by Model::coriolis, matching libfranka’s RobotModel::coriolis fallback of {0, 0, -9.81}.

FER_URDF

The Franka Emika Robot (FER)’s arm, as a URDF the native_backend can evaluate.

FR3_URDF

The FR3 URDF from franka_description that the tests and franka-rerun replays use.

Traits

RobotModelBackend

Rigid-body model backend.