Crate dynamics_joint 

This crate is part of the dynamics ecosystem, and is not intended for direct use.

This module provides structures and traits to represent joints in a robot model.

Architecture

In order to use static dispatch for different joint types while maintaining a common interface, the following architecture is implemented:

• The JointModel trait defines the common interface, implemented by specific joint types.
• Different joint types (e.g., JointModelContinuous, JointModelPrismatic, JointModelRevolute, JointModelFixed) implement the JointModel trait.
• The JointModelImpl enum encapsulates different joint model implementations.
• The JointWrapper struct provides a unified interface to interact with different joint types through the JointModel trait. This is the main entry point for users of the library.

Joint types

The following joint types are implemented:

• continuous::JointModelContinuous: Represents a continuous joint that can rotate indefinitely around a fixed axis.
• prismatic::JointModelPrismatic: Represents a prismatic joint that allows linear motion along a fixed axis.
• revolute::JointModelRevolute: Represents a revolute joint that allows rotation around a fixed axis with limits. This is similar to the continuous joint but with defined limits on the rotation.
• fixed::JointModelFixed: Represents a fixed joint with no degrees of freedom.

The following table summarizes the number of configuration variables (nq) and velocity variables (nv) for each joint type:

Joint	nq	nv	Description
Continuous	2	1	Unbounded rotation
Prismatic	1	1	Linear motion
Revolute	1	1	Bounded rotation
Fixed	0	0	No motion

Modules

continuous

Continuous joint, constraining two objects to rotate around a given axis, without limits.

fixed

Fixed joint, without any degree of freedom.

joint

Defines a generic joint model trait and a struct to wrap different joint types.

joint_data

Structure containing the mutable properties of a joint.

limits

Defines joint limits and related operations.

prismatic

Prismatic joint, constraining two objects to translate along a given axis.

revolute

Revolute joint, constraining two objects to rotate around a given axis.