Enum JointType

pub enum JointType {
    Fixed,
    Revolute,
    Continuous,
    Prismatic,
    Floating,
    Planar,
}

An enum to represent the the types of Joint.

Currently, only URDF types are listed.

It is important to note that multi-axis jointtypes, like Floating and Planar, are often incompatible with lots of different tooling for ROS/URDF, like sensor_msgs/JointState messages from for example joint_state_publisher which has chosen to ignore it. This is a result of most programs (like kdl_parser and joint_state_publisher) only supporting single axis joints. Gazebo/SDFormat supports multi-access joints, but do not have an Floating or Planar equivalent. However, these JointTypes (Mostly Planar) can be approximated by a combination of other joints.

The sections cited from the URDF specification are accurate as of 2023-08-21.

Variants

Fixed

A Fixed joint.

The URDF Specification says the following:

fixed — this is not really a joint because it cannot move. All degrees of freedom are locked. This type of joint does not require the <axis>, <calibration>, <dynamics>, <limits> or <safety_controller>.

Revolute

A Revolute joint. (A limited rotational joint, like a weld)

This joint rotates a limited range around a specified (or default) axis.

The URDF Specification says the following:

revolute — a hinge joint that rotates along the axis and has a limited range specified by the upper and lower limits.

Continuous

A Continuous rotational joint. (A bearing or motor connection, like a wheel)

This joint rotates around a specified (or default) axis.

Since this Jointtype is unlimited in its movement, the Limit should not be specified (??TODO: effort and velocity migth be useable??).

The URDF Specification says the following:

continuous — a continuous hinge joint that rotates around the axis and has no upper and lower limits.

Prismatic

A Prismitic joint. (A limited sliding joint, like a drawer rail or a linear actuator)

This joint slides a limited range along a specified (or default) axis.

The URDF Specification says the following:

prismatic — a sliding joint that slides along the axis, and has a limited range specified by the upper and lower limits.

Floating

A Floating joint. (Or a non-connection)

This is a joint to represent an unconnected link. Most parsers do not handle this JointType, since it’s not an actual joint and it causes problems with lots of different tooling for ROS/URDF, like sensor_msgs/JointState messages from for example joint_state_publisher which has chosen to ignore it.

The URDF Specification says the following:

floating — this joint allows motion for all 6 degrees of freedom.

Planar

A Planar joint. (A plane contact, like a magnet on a metal sheet)

This joint slides on the plane perpendicular the specified (or default) axis. This JointType might cause problems with lots of different tooling for ROS/URDF, like sensor_msgs/JointState messages from for example joint_state_publisher which has chosen to ignore it.

The URDF Specification says the following:

planar — this joint allows motion in a plane perpendicular to the axis.

Trait Implementations

impl Clone for JointType

fn clone(&self) -> JointType

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for JointType

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for JointType

fn default() -> JointType

Returns the “default value” for a type.

impl From<JointType> for Cow<'_, [u8]>

fn from(value: JointType) -> Self

Converts to this type from the input type.

impl PartialEq for JointType

fn eq(&self, other: &JointType) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl ToString for JointType

fn to_string(&self) -> String

Converts the given value to a String.

impl Copy for JointType

impl Eq for JointType

impl StructuralPartialEq for JointType