29 lines
558 B
Mathematica
29 lines
558 B
Mathematica
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function [S, theta] = AxisAng6(expc6)
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% *** CHAPTER 3: RIGID-BODY MOTIONS ***
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% Takes a 6-vector of exponential coordinates for rigid-body motion
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% S*theta.
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% Returns S: the corresponding normalized screw axis,
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% theta: the distance traveled along/about S.
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% Example Input:
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%
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% clear; clc;
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% expc6 = [1; 0; 0; 1; 2; 3];
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% [S, theta] = AxisAng6(expc6)
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%
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% Output:
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% S =
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% 1
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% 0
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% 0
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% 1
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% 2
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% 3
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% theta =
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% 1
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theta = norm(expc6(1: 3));
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if NearZero(theta)
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theta = norm(expc6(4: 6));
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end
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S = expc6 / theta;
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end
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