Modern_Robotics/code/MATLAB/VelQuadraticForces.m

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%*** CHAPTER 8: DYNAMICS OF OPEN CHAINS ***
function c = VelQuadraticForces(thetalist,dthetalist,Mlist,Glist,Slist)
% Takes thetalist: A list of joint variables,
% dthetalist: A list of joint rates,
% Mlist: List of link frames i relative to i-1 at the home position,
% Glist: Spatial inertia matrices Gi of the links,
% Slist: Screw axes Si of the joints in a space frame.
% Returns c: The vector c(thetalist,dthetalist) of Coriolis and centripetal
% terms for a given thetalist and dthetalist.
% This function calls InverseDynamics with g = 0, Ftip = 0, and
% ddthetalist = 0.
% Example Input (3 Link Robot):
%{
clear;clc;
thetalist = [0.1; 0.1; 0.1];
dthetalist = [0.1; 0.2; 0.3];
M01 = [[1, 0, 0, 0]; [0, 1, 0, 0]; [0, 0, 1, 0.089159]; [0, 0, 0, 1]];
M12 = [[0, 0, 1, 0.28]; [0, 1, 0, 0.13585]; [-1, 0 ,0, 0]; [0, 0, 0, 1]];
M23 = [[1, 0, 0, 0]; [0, 1, 0, -0.1197]; [0, 0, 1, 0.395]; [0, 0, 0, 1]];
M34 = [[1, 0, 0, 0]; [0, 1, 0, 0]; [0, 0, 1, 0.14225]; [0, 0, 0, 1]];
G1 = diag([0.010267, 0.010267, 0.00666, 3.7, 3.7, 3.7]);
G2 = diag([0.22689, 0.22689, 0.0151074, 8.393, 8.393, 8.393]);
G3 = diag([0.0494433, 0.0494433, 0.004095, 2.275, 2.275, 2.275]);
Glist = cat(3,G1,G2,G3);
Mlist = cat(4,M01,M12,M23,M34);
Slist = [[1; 0; 1; 0; 1; 0], ...
[0; 1; 0; -0.089; 0; 0], ...
[0; 1; 0; -0.089; 0; 0.425]];
c = VelQuadraticForces(thetalist,dthetalist,Mlist,Glist,Slist)
%}
% Output:
% c =
% 0.2645
% -0.0551
% -0.0069
c = InverseDynamics(thetalist,dthetalist,zeros(size(thetalist,1),1), ...
[0; 0; 0],[0; 0; 0; 0; 0; 0],Mlist,Glist,Slist);
end