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cosmic_power 059831c913 Kinematics matched with robotics toolbox 2024-01-07 16:01:08 +08:00
6 changed files with 393 additions and 0 deletions

6
Identification_main.m Normal file
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file = [];
opt.robot_def = 'direct';
opt.KM_method = 'MDH';
robot = get_robot(file,opt);
robot.theta = [1,0,0];
robot = get_Kinematics(robot, opt);

29
get_Kinematics.m Normal file
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function robot = get_Kinematics(robot, opt)
switch opt.KM_method
case 'SDH'
case 'MDH'
theta = robot.theta;
alpha = robot.alpha;
a = robot.a;
d = robot.d;
robot.Fkine = eye(4,4);
ndof = length(theta); % special for MDH
% init transform matrix
robot.R = zeros([3,3,ndof]);
robot.t = zeros([3,1,ndof]);
robot.T = zeros([4,4,ndof]);
for i = 1:ndof
robot.R(:,:,i) = [cos(theta(i)) -sin(theta(i)) 0;...
sin(theta(i))*cos(alpha(i)) cos(theta(i))*cos(alpha(i)) -sin(alpha(i));...
sin(theta(i))*sin(alpha(i)) cos(theta(i))*sin(alpha(i)) cos(alpha(i))];
robot.t(:,:,i) = [a(i);-d(i)*sin(alpha(i));d(i)*cos(alpha(i))];
Transform = eye(4,4);
Transform(1:3,1:3) = robot.R(:,:,i);
Transform(1:3,4) = robot.t(:,:,i);
robot.T(:,:,i) = Transform;
robot.Fkine = robot.Fkine*robot.T(:,:,i);
end
otherwise
disp('Bad opt.KM_method!')
return;
end

92
get_rb_dynamics.m Normal file
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function [taulist]= get_rb_dynamics(thetalist, dthetalist, ddthetalist, g,...
dh_list, mass_list, mass_center_list, inertia_tensor_list, f_tip)
%--------------------------
% thetalist:6x1,dthetalist:6x1,, ddthetalist:6x1,
% g: 1x1,
% dh_list:6x4,modified_DH
% mass_list:6x1,mass_center_list:6x3,{i}
% inertia_tensor_list: 3x3x6,
% f_tip: 2x3,
%taulist:6x1,
%R3x3x6,P3x6,
%w3x6,dw3x6,dv3x6,线dvc3x6,线
%Ic:3x3x6,inertia_tensor_list
%Pc:3x6, mass_center_list
%F:3x6,N:3x6,
%f:3x6,n:3x6,
dof_num = size(dthetalist,1);
alpha = dh_list(:,1);
a = dh_list(:,2);
d = dh_list(:,3);
theta = dh_list(:,4);
m = mass_list;
Pc = mass_center_list';
Ic = inertia_tensor_list;
Z=[0;0;1];
%
theta = theta + thetalist;
T=zeros(4,4,dof_num);R=zeros(3,3,dof_num);P=zeros(3,dof_num);
for i=1:dof_num
T(:,:,i)=[cos(theta(i)) -sin(theta(i)) 0 a(i)
sin(theta(i))*cos(alpha(i)) cos(theta(i))*cos(alpha(i)) -sin(alpha(i)) -d(i)*sin(alpha(i))
sin(theta(i))*sin(alpha(i)) cos(theta(i))*sin(alpha(i)) cos(alpha(i)) d(i)*cos(alpha(i))
0 0 0 1];
R(:,:,i)=T(1:3,1:3,i);
P(:,i)=T(1:3,4,i);
end
TT = eye(4,4);
for i = 1:dof_num
TT = TT*T(:,:,i);
end
%
w0 = zeros(3,1); dw0 = zeros(3,1);
dv0 = [0;0;g];
w = zeros(3,dof_num); dw = zeros(3,dof_num);
dv = zeros(3,dof_num); dvc = zeros(3,dof_num);
F = zeros(3,dof_num); N = zeros(3,dof_num);
%i = 0
w(:,1) = R(:,:,1)' * w0 + dthetalist(1) * Z;
dw(:,1) = R(:,:,1)' * dw0 + cross(R(:,:,1)' * w0, dthetalist(1) * Z) + ddthetalist(1) * Z;
dv(:,1) = R(:,:,1)' * (cross(dw0,P(:,1)) + cross(w0,cross(w0, P(:,1))) + dv0);
dvc(:,1) = cross(dw(:,1), Pc(:,1))+cross(w(:,1), cross(w(:,1), Pc(:,1))) + dv(:,1);
for i = 1:dof_num-1
w(:,i+1) = R(:,:,i+1)' * w(:,i) + dthetalist(i+1) * Z ;
dw(:,i+1) = R(:,:,i+1)' * dw(:,i) + cross(R(:,:,i+1)' * w(:,i), dthetalist(i+1) * Z)+ ddthetalist(i+1) * Z;
dv(:,i+1) = R(:,:,i+1)' * (cross(dw(:,i), P(:,i+1)) + cross(w(:,i), cross(w(:,i), P(:,i+1))) + dv(:,i));
dvc(:,i+1) = cross(dw(:,i+1), Pc(:,i+1)) + cross(w(:,i+1), cross(w(:,i+1), Pc(:,i+1))) + dv(:,i+1);
end
for i = 1:dof_num
F(:,i)=m(i)*dvc(:,i) ;
N(:,i)=Ic(:,:,i) * dw(:,i) + cross(w(:,i), Ic(:,:,i) * w(:,i));
end
%
%6
taulist = zeros(dof_num,1);
f=zeros(3,dof_num); n=zeros(3,dof_num);
f(:,dof_num) = F(:,dof_num) + f_tip(1,:)';
n(:,dof_num) = N(:,dof_num) + f_tip(2,:)' + cross(Pc(:,dof_num), F(:,dof_num));
taulist(dof_num) = n(:,dof_num)' * Z;
%51
for i=dof_num-1:-1:1
f(:,i) = R(:,:,i+1) * f(:,i+1) + F(:,i);
n(:,i) = N(:,i) + R(:,:,i+1) * n(:,i+1) + cross(Pc(:,i), F(:,i))...
+ cross(P(:,i+1), R(:,:,i+1) * f(:,i+1));
taulist(i) = n(:,i)' * Z;
end
end

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get_rne_mdh.m Normal file
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function tau = get_rne_mdh(robot, a1, a2, a3, a4, a5)
z0 = [0;0;1];
grav = robot.gravity; % default gravity from the object
fext = zeros(6, 1);
% Set debug to:
% 0 no messages
% 1 display results of forward and backward recursions
% 2 display print R and p*
debug = 0;
n = robot.n;
if numcols(a1) == 3*n
Q = a1(:,1:n);
Qd = a1(:,n+1:2*n);
Qdd = a1(:,2*n+1:3*n);
np = numrows(Q);
if nargin >= 3,
grav = a2(:);
end
if nargin == 4
fext = a3;
end
else
np = numrows(a1);
Q = a1;
Qd = a2;
Qdd = a3;
if numcols(a1) ~= n || numcols(Qd) ~= n || numcols(Qdd) ~= n || ...
numrows(Qd) ~= np || numrows(Qdd) ~= np
error('bad data');
end
if nargin >= 5,
grav = a4(:);
end
if nargin == 6
fext = a5;
end
end
if robot.issym || any([isa(Q,'sym'), isa(Qd,'sym'), isa(Qdd,'sym')])
tau = zeros(np,n, 'sym');
else
tau = zeros(np,n);
end
for p=1:np
q = Q(p,:).';
qd = Qd(p,:).';
qdd = Qdd(p,:).';
Fm = [];
Nm = [];
pstarm = [];
Rm = [];
w = zeros(3,1);
wd = zeros(3,1);
vd = grav(:);
%
% init some variables, compute the link rotation matrices
%
for j=1:n
link = robot.links(j);
Tj = link.A(q(j));
switch link.type
case 'R'
D = link.d;
case 'P'
D = q(j);
end
alpha = link.alpha;
pm = [link.a; -D*sin(alpha); D*cos(alpha)]; % (i-1) P i
if j == 1
pm = t2r(robot.base) * pm;
Tj = robot.base * Tj;
end
Pm(:,j) = pm;
Rm{j} = t2r(Tj);
if debug>1
Rm{j}
Pm(:,j).'
end
end
%
% the forward recursion
%
for j=1:n
link = robot.links(j);
R = Rm{j}.'; % transpose!!
P = Pm(:,j);
Pc = link.r;
%
% trailing underscore means new value
%
switch link.type
case 'R'
% revolute axis
w_ = R*w + z0*qd(j);
wd_ = R*wd + cross(R*w,z0*qd(j)) + z0*qdd(j);
%v = cross(w,P) + R*v;
vd_ = R * (cross(wd,P) + ...
cross(w, cross(w,P)) + vd);
case 'P'
% prismatic axis
w_ = R*w;
wd_ = R*wd;
%v = R*(z0*qd(j) + v) + cross(w,P);
vd_ = R*(cross(wd,P) + ...
cross(w, cross(w,P)) + vd ...
) + 2*cross(R*w,z0*qd(j)) + z0*qdd(j);
end
% update variables
w = w_;
wd = wd_;
vd = vd_;
vdC = cross(wd,Pc).' + ...
cross(w,cross(w,Pc)).' + vd;
F = link.m*vdC;
N = link.I*wd + cross(w,link.I*w);
Fm = [Fm F];
Nm = [Nm N];
if debug
fprintf('w: '); fprintf('%.3f ', w)
fprintf('\nwd: '); fprintf('%.3f ', wd)
fprintf('\nvd: '); fprintf('%.3f ', vd)
fprintf('\nvdbar: '); fprintf('%.3f ', vdC)
fprintf('\n');
end
end
%
% the backward recursion
%
fext = fext(:);
f = fext(1:3); % force/moments on end of arm
nn = fext(4:6);
for j=n:-1:1
%
% order of these statements is important, since both
% nn and f are functions of previous f.
%
link = robot.links(j);
if j == n
R = eye(3,3);
P = [0;0;0];
else
R = Rm{j+1};
P = Pm(:,j+1); % i/P/(i+1)
end
Pc = link.r;
f_ = R*f + Fm(:,j);
nn_ = Nm(:,j) + R*nn + cross(Pc,Fm(:,j)).' + ...
cross(P,R*f);
f = f_;
nn = nn_;
if debug
fprintf('f: '); fprintf('%.3f ', f)
fprintf('\nn: '); fprintf('%.3f ', nn)
fprintf('\n');
end
switch link.type
case 'R'
% revolute
tau(p,j) = nn.'*z0 + ...
link.G^2 * link.Jm*qdd(j) - ...
friction(link, qd(j));
case 'P'
% prismatic
tau(p,j) = f.'*z0 + ...
link.G^2 * link.Jm*qdd(j) - ...
friction(link, qd(j));
end
end
end

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get_robot.m Normal file
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function robot = get_robot(file,opt)
switch opt.robot_def
case 'direct'
ndof = 2;
% Kinematics parameters
switch opt.KM_method
case 'SDH'
case 'MDH'
robot.theta = zeros([1,ndof+1]);
robot.a = [0,1,1];
robot.d = [0,0,0];
robot.alpha = [0,0,0];
otherwise
disp('Bad opt.KM_method!')
return;
end
% Dynamics parameters
link_mass = [1,1];
axis_of_rot(:,:,1) = [0;0;1];
axis_of_rot(:,:,2) = [0;0;1];
com_pos(:,:,1) = [1/2;0;0];
com_pos(:,:,2) = [1/2;0;0];
% the inertia tensor wrt the frame oriented as the body frame and with the
% origin in the COM
link_inertia(:,:,1) = diag([1,1,1]);
link_inertia(:,:,2) = diag([1,1,1]);
% manipulator regressor
for i = 1:ndof
robot.m(i) = link_mass(i);
robot.axis(:,i) = axis_of_rot(i);
robot.com(:,i) = com_pos(i);
robot.I(:,:,i) = link_inertia(i);
robot.mc(:,i) = link_mass*com_pos(i);
% the inertia tensor wrt the frame oriented as the body frame and with the
% origin in the Joint i
com_vec2mat = vec2skewSymMat(com_pos);
robot.I_vec(:,i) = inertiaMatrix2Vector(link_inertia-...
link_mass(i)*com_vec2mat*com_vec2mat);
robot.pi(:,i) = [robot.I_vec(:,i); robot.mc(:,i); robot.m(i)];
end
case 'urdf'
robot = parse_urdf(file);
case 'mat'
robot = [];
disp('TODO mat robot define options!')
otherwise
robot = [];
disp('Bad robot define options!')
return
end

28
test_kinematics.m Normal file
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mdh = 1;
if mdh==1
% theta d a alpha offset
L1=Link('revolute', 'd', 0, 'a', 0, 'alpha', 0, 'offset',0,'qlim',deg2rad([-20,40]),'modified');
L2=Link('revolute', 'd', 0, 'a', 1, 'alpha', 0, 'offset',0,'qlim',deg2rad([-20,45]),'modified');
L3=Link('revolute', 'd', 0, 'a', 1, 'alpha', 0, 'offset',0,'qlim',deg2rad([-20,45]),'modified');
Two_bar=SerialLink([L1 L2 L3],'name','Two_bar'); %
Two_bar.teach();
% Two_bar.plot([0 0])%
else
% theta d a alpha offset
L1=Link('revolute', 'd', 0, 'a', 1, 'alpha', 0, 'offset',0,'qlim',deg2rad([-20,40]),'standard');
L2=Link('revolute', 'd', 0, 'a', 1, 'alpha', 0, 'offset',0,'qlim',deg2rad([-20,45]),'standard');
Two_bar=SerialLink([L1 L2],'name','Two_bar'); %
% Two_bar.plot([0 0])%
Two_bar.teach();
end
% a = [0, -0.42500, -0.39225, 0, 0, 0];
% d = [0.0892, 0, 0, 0.10915, 0.09465, 0.0823];
% alpha = [1.570796327, 0, 0, 1.570796327, -1.570796327, 0];
% for i = 1:6
% L(i)=Link([0 d(i) a(i) alpha(i)]);
% L(i).qlim=[-2*pi,2*pi];
% end
% UR5=SerialLink(L,'name','UR5');
% UR5.teach();