quaternion

Class: simscape.multibody.Rotation
Namespace: simscape.multibody

Compute unit quaternion of rotation

Since R2022a

Syntax

Q = quaternion(R)

Description

Q = quaternion(R) computes the unit quaternion of the desired rotation, R and returns a 4-by-1 unit vector,

$$Q=\left(\begin{array}{cc}S& V\end{array}\right)$$,

where:

$$S=\cos \left(\frac{\theta }{2}\right)$$,

and

$$V=[U_x{U}_y{U}_z]\sin \left(\frac{\theta }{2}\right)$$.

θ is the angle of rotation and [U_x, U_y, U_z] is the unit vector of the rotational axis. Note that for any given rotation, there are two unit quaternions that are negatives of each other, but represent the same rotation. For example, the quaternions [1 0 0 0] and [-1 0 0 0] both represent the identity rotation.

Input Arguments

R — Rotation

object of subclass of simscape.multibody.Rotation class

Rotation, specified as an object of a subclass of the simscape.multibody.Rotation class.

Output Arguments

Q — Unit quaternion of rotation

quaternion object

Unit quaternion of the rotation, returned as a quaternion object that represents a four-element unit row vector.

Attributes

Access

public

To learn about attributes of methods, see Method Attributes.

Version History

Introduced in R2022a