39 lines
1.6 KiB
Matlab
39 lines
1.6 KiB
Matlab
function [Li, dLi] = inverseKinematics(stewart, args)
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% inverseKinematics - Compute the needed length of each strut to have the wanted position and orientation of {B} with respect to {A}
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%
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% Syntax: [stewart] = inverseKinematics(stewart)
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%
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% Inputs:
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% - stewart - A structure with the following fields
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% - geometry.Aa [3x6] - The positions ai expressed in {A}
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% - geometry.Bb [3x6] - The positions bi expressed in {B}
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% - geometry.l [6x1] - Length of each strut
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% - args - Can have the following fields:
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% - AP [3x1] - The wanted position of {B} with respect to {A}
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% - ARB [3x3] - The rotation matrix that gives the wanted orientation of {B} with respect to {A}
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%
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% Outputs:
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% - Li [6x1] - The 6 needed length of the struts in [m] to have the wanted pose of {B} w.r.t. {A}
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% - dLi [6x1] - The 6 needed displacement of the struts from the initial position in [m] to have the wanted pose of {B} w.r.t. {A}
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arguments
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stewart
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args.AP (3,1) double {mustBeNumeric} = zeros(3,1)
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args.ARB (3,3) double {mustBeNumeric} = eye(3)
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end
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assert(isfield(stewart.geometry, 'Aa'), 'stewart.geometry should have attribute Aa')
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Aa = stewart.geometry.Aa;
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assert(isfield(stewart.geometry, 'Bb'), 'stewart.geometry should have attribute Bb')
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Bb = stewart.geometry.Bb;
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assert(isfield(stewart.geometry, 'l'), 'stewart.geometry should have attribute l')
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l = stewart.geometry.l;
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Li = sqrt(args.AP'*args.AP + diag(Bb'*Bb) + diag(Aa'*Aa) - (2*args.AP'*Aa)' + (2*args.AP'*(args.ARB*Bb))' - diag(2*(args.ARB*Bb)'*Aa));
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dLi = Li-l;
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end
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