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annotate scripts/quaternion/qderiv.m @ 3224:1e7532b9173b

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[project @ 1998-12-04 22:08:23 by jwe]
author jwe
date Fri, 04 Dec 1998 22:08:23 +0000
parents
children a892190f4977
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3224
1e7532b9173b [project @ 1998-12-04 22:08:23 by jwe]
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1 function Dmat = qderivmat(Omega)
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2 # function Dmat = qderivmat(Omega)
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3 # Derivative of a quaternion.
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4 # Let Q be a quaternion to transform a vector from a fixed frame to
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5 # a rotating frame. If the rotating frame is rotating about the
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6 # [x,y,z] axes at angular rates [wx, wy, wz], then the derivative
1e7532b9173b [project @ 1998-12-04 22:08:23 by jwe]
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7 # of Q is given by
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8 # Q' = qderivmat(Omega)*Q
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9 #
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10 # If the passive convention is used (rotate the frame, not the vector),
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11 # then Q' = -qderivmat(Omega)*Q; see the accompanying document
1e7532b9173b [project @ 1998-12-04 22:08:23 by jwe]
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12 # quaternion.ps for details.
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13
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14 Omega = vec(Omega);
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15 if(length(Omega) != 3)
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16 error("qderivmat: Omega must be a length 3 vector.");
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17 endif
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18
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19 Dmat = 0.5*[ 0.0, Omega(3), -Omega(2), Omega(1); ...
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20 -Omega(3), 0.0, Omega(1), Omega(2); ...
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21 Omega(2), -Omega(1), 0.0, Omega(3); ...
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22 -Omega(1), -Omega(2), -Omega(3), 0.0 ];
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23 endfunction