Dongjun Lee
Rigid Body Rotation and SO(3)
Dongjun Lee (이동준)
Department of Mechanical & Aerospace Engineering Seoul National University
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Attaching Coordinate Frames
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Coordinate Frames: Examples
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Joint Space Q and Workspace W
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Configuration Space C
posture C
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Rigid Body Transformation
{B(0)}
{B(t)}
{A}
p(0)
p(t)=g(p(0))
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Free Vector
{B(0)}
{B(t)}
{A}
p
g(p)
r g(q)
s q g(r)
g(s)
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Rigid Transformation: Definition
{B(0)} {B(t)}
{A}
p
g(p) g(q) q
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Rotation Matrix R
{A}
xb
yb zb
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Three Roles of R
q(0) {A}
q(t)
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Properties of R
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Properties of R
v w x
Rv Rw x
v x w R(v x w)=Rv x Rw
R R
R
body‐frame inertial‐frame
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Properties of R
xb yb
xa ya
R
body‐frame
inertial‐frame w^
R (Rw)^
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Composition of Rotations
{A} {A}
y
z
x {C}
xa
ya za
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Composition of Rotations
xb yb
xa ya
R1
frame {B}
frame {A}
R2^b
R1 R2^a
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Special Orthogonal Group SO(3)
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Exponential of w
{A}
w q(0) {B(t)}
q(t)
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Angular Velocity and so(3)
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Rodrigues’ Formula
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Exponential Coordinates for SO(3)
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Logarithm Map for SO(3)
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Equivalent Axis Representation
{A}
w {B(t)}
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Exponential Coordinates in Different Frames
xb yb
xa ya
Rab Rab
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Geometric Meaning of exp(wat) and exp(wbt)
{A}
{B1} w t
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Rotational Velocity
{A}
g(t) w
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Parameterization of SO(3): Euler Angle
{A}
xb
yb zb
x
y z
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Parameterization of SO(3): Euler Angle
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Parameterization of SO(3): Quaternions
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Parameterization of SO(3): Quaternions