Incorporate xenia-nonlinear branch changes

- Copy-paste `xenia_nonlinearopt.m` from xenia-nonlinear branch
This commit is contained in:
Sravan Balaji
2021-12-09 12:58:51 -05:00
parent f7b9eb687c
commit c3c9546342

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@@ -1,3 +1,4 @@
%% initial conditions
%Vehicle Parameterrs
Nw=2;
f=0.01;
@@ -30,131 +31,126 @@ curr_pos = [init(1);init(3)];
% [g,h,dg,dh]=nonlcon(z, Xobs, nsteps);
% [J, dJ] = costfun(z, TestTrack.cline(:,1), TestTrack.theta(1), nsteps);
%%okay, idea is to create an iterative process that uses the centerline as a
%checkpoint
%keep trajecting until closer to the next point on centerline, then repeat
%bounds will be based on index of current&previous cp index
%cost function uses next checkpoint in centerline
%generate z and make it bigger if didn't reach close enough to the goal
%(modify nsteps)
Nobs = randi([10 25], 1,1);
global Xobs
Xobs = generateRandomObstacles(Nobs);
% global index_cl_cp %index of current checkpoint in centerline
% index_cl_cp = 1;
% global index_cl_nextcp %index of next checkpoint in centerline
% index_cl_nextcp = 2;
%
% global nsteps
% nsteps = 100;
% x0 = init;
% x0vec = [];
% %initialize x0vec to be initial condition for n steps and Sravan's ref inputs
% %note: function 'initvec' changes inputs, but i'm not sure how
% %initialization should look with fmincon
% for i = 1:nsteps
% x0vec = [x0vec, init];
% end
% for i = 1:nsteps-1
% x0vec = [x0vec, -0.004, 3900];
% end
% dist12atcp = [];
% iter = 0;
%
% factor = 0.1; %next checkpoint if significantly closer to next checkpoint
U_final = [];
Y_final = [];
options = optimoptions('fmincon','SpecifyConstraintGradient',true,...
'SpecifyObjectiveGradient',true) ;
load('ROB535_ControlProject_part1_Team3.mat');
%[Y_submission, T_submission] = forwardIntegrateControlInput(ROB535_ControlProject_part1_input, init);
load('reftrack_info.mat');
load('segments_info.mat');
for i = 1:length(num_pts)
[start_idx, end_idx] = get_indices(i, num_pts);
%% MPC
U_ref = ROB535_ControlProject_part1_input';
Y_ref = Y_submission';
dt = 0.01;
delta = delta_vals(i);
F_x = F_x_vals(i);
%discretize dynamics
F_zf=b/(a+b)*m*g;
F_zr=a/(a+b)*m*g;
if (end_idx >= size(Y_submission,1))
start_idx = start_idx - 1;
end_idx = end_idx - 1;
end
%we are just going to use cornering stiffness to make linear so this derivative
%easier, the vehicle parameter's are close enough to problem 1 hw 2
B=10;
C=1.3;
D=1;
Ca_r= F_zr*B*C*D;
Ca_f= F_zf*B*C*D;
x0 = [];
for j = start_idx:end_idx+1 %+1 end idx to keep z size consistent to hw
x0 = [x0, Y_submission(j,:)];
end
x = @(s,i) Y_ref(s,i);
for j = start_idx:end_idx
x0 = [x0, delta, F_x];
end
Ac = @(i) [0, cos(x(5,i)), 0, -sin(x(5,i)), x(2,i)*sin(x(5,i))-x(4,i)*cos(x(5,i)), 0;
0, (-1/m)*Ca_f*x(2,i)^-2, 0, -Ca_f/m + 1, 0, Ca_f*(-a/m) + 1;
0, sin(x(5,i)), 0, cos(x(5,i)), -x(4,i)*sin(x(5,i))+x(2,i)*cos(x(5,i)), 0;
0, (1/m)*(-Ca_f*x(2,i)^-2 - Ca_r*x(2,i)^-2) - 1, 0, Ca_r/m*(-1/x(2,i)) + Ca_f/m*(-1/x(2,i)), 0, Ca_r/m*(b/x(2,i)) + Ca_f/m*(-a/x(2,i)) - x(2,i);
0, 0, 0, 0, 0, 1
0, (1/Iz)*(-Ca_f*a*x(2,i)^-2 - b*Ca_r*x(2,i)^-2), 0, -b*Ca_r/Iz*(-1/x(2,i)) + a*Ca_f/Iz*(-1/x(2,i)), 0, -b*Ca_r/Iz*(b/x(2,i)) + a*Ca_f/Iz*(-a/x(2,i))];
%start and end index used to maintain size of vectors
[lb, ub] = bounds(start_idx, end_idx);
Bc = @(i) [0, -Ca_f/m, 0, Ca_f/m, 0, a*Ca_f/Iz;
0, Nw/m, 0, 0, 0, 0]';
%define for cost function, goal is to reach end of segment
global target_vec
target_vec = [Y_submission(end_idx,1), Y_submission(end_idx,3), Y_submission(end_idx,5)];
A = @(i) eye(6) + dt*Ac(i);
B = @(i) dt*Bc(i);
global nsteps
nsteps = num_pts(i)+1;
cf=@costfun
nc=@nonlcon
z=fmincon(cf,x0,[],[],[],[],lb',ub',nc,options);
Y0=reshape(z(1:6*nsteps),6,nsteps)';
U=reshape(z(6*nsteps+1:end),2,nsteps-1)';
info = getTrajectoryInfo(Y0,U)
U_final = [U_final; U];
%Decision variables
npred = 10;
nstates = 6;
ninputs = 2;
Ndec=(npred+1)*nstates+ninputs*npred;
input_range = [-0.5, 0.5; -5000, 5000];
eY0 = init';
[Aeq_test1,beq_test1]=eq_cons(1,A,B,eY0,npred,nstates,ninputs);
%simulate forward
T = 0:0.01:(size(Y_ref,2)/100);
%final trajectory
Y=NaN(nstates,length(T));
%applied inputs
U=NaN(ninputs,length(T));
%input from QP
u_mpc=NaN(ninputs,length(T));
%error in states (actual-reference)
eY=NaN(nstates,length(T));
%set random initial condition
Y(:,1)=eY0+Y_ref(:,1);
for i=1:length(T)-1
i
%shorten prediction horizon if we are at the end of trajectory
npred_i=min([npred,length(T)-i]);
%calculate error
eY(:,i)=Y(:,i)-Y_ref(:,i);
%generate equality constraints
[Aeq,beq]=eq_cons(i,A,B,eY(:,i),npred_i,nstates,ninputs);
%generate boundary constraints
[Lb,Ub]=bound_cons(i,U_ref,npred_i,input_range,nstates,ninputs);
%cost for states
Q=[1,1,1,1,1,1];
%cost for inputs
R=[0.1,0.01];
H=diag([repmat(Q,[1,npred_i+1]),repmat(R,[1,npred_i])]);
f=zeros(nstates*(npred_i+1)+ninputs*npred_i,1);
[x,fval] = quadprog(H,f,[],[],Aeq,beq,Lb,Ub);
%get linearized input
u_mpc(:,i)=x(nstates*(npred_i+1)+1:nstates*(npred_i+1)+ninputs);
%get input
U(:,i)=u_mpc(:,i)+U_ref(:,i);
%simulate model
[~,ztemp]=ode45(@(t,z)kinematic_bike(t,z,U(:,i),0),[0 dt],Y(:,i));
%store final state
Y(:,i+1)=ztemp(end,:)';
end
% while (index_cl_cp < size(TestTrack.cline,2))
% %because of the way cf/nc need to be)
% index_cl_cp
% iter = iter + 1;
% [lb, ub] = bounds(nsteps, index_cl_cp);
% cf=@costfun
% nc=@nonlcon
% z=fmincon(cf,x0vec,[],[],[],[],lb',ub',nc,options);
% Y0=reshape(z(1:6*nsteps),6,nsteps)';
% U=reshape(z(6*nsteps+1:end),2,nsteps-1)';
%
% [Y, T] = forwardIntegrateControlInput(U, x0vec(1:6));
%
% curr_xy = [Y(end,1); Y(end,3)];
% dist2cp1 = norm(curr_xy - TestTrack.cline(:, index_cl_cp));
% dist2cp2 = norm(curr_xy - TestTrack.cline(:, index_cl_nextcp));
%
% if (dist2cp2 < (dist2cp1 - dist2cp1*factor))
% dist12atcp = [dist12atcp; dist2cp1, dist2cp2];
% %add to final solution
% U_final = [U_final; U];
% Y_final = [Y_final; Y];
%
% %reinstantiate
% %nsteps = 100;
% x0vec = initvec(Y_final(end,:), U_final(end,:));
%
% %update checkpoint
% index_cl_cp = index_cl_cp + 1
% index_cl_nextcp = index_cl_nextcp + 1;
% if (index_cl_nextcp > size(TestTrack.cline, 2))
% index_cl_nextcp = size(TestTrack.cline, 2);
% end
% else
% %resize and try again
% %nsteps = nsteps + 20;
% x0vec = initvec(x0vec(1:6), U(1,:));
%
% end
%
% end
%% function start
function [start_idx, end_idx] = get_indices(segment_num, num_pts)
if segment_num == 1
@@ -166,6 +162,7 @@ function [start_idx, end_idx] = get_indices(segment_num, num_pts)
end
end
%not used
function x0vec = initvec(x0, u0)
%function used because fmincon needs initial condition to be size of
%state vector
@@ -184,6 +181,115 @@ function x0vec = initvec(x0, u0)
end
end
%% mpc functions
function [Aeq,beq]=eq_cons(initial_idx,A,B,x_initial,npred,nstates,ninputs)
%build matrix for A_i*x_i+B_i*u_i-x_{i+1}=0
%in the form Aeq*z=beq
%initial_idx specifies the time index of initial condition from the reference trajectory
%A and B are function handles above
%initial condition
x_initial=x_initial(:);
%size of decision variable and size of part holding states
zsize=(npred+1)*nstates+npred*ninputs;
xsize=(npred+1)*nstates;
Aeq=zeros(xsize,zsize);
Aeq(1:nstates,1:nstates)=eye(nstates); %initial condition
beq=zeros(xsize,1);
beq(1:nstates)=x_initial;
state_idxs=nstates+1:nstates:xsize;
input_idxs=xsize+1:ninputs:zsize;
for i=1:npred
%negative identity for i+1
Aeq(state_idxs(i):state_idxs(i)+nstates-1,state_idxs(i):state_idxs(i)+nstates-1)=-eye(nstates);
%A matrix for i
Aeq(state_idxs(i):state_idxs(i)+nstates-1,state_idxs(i)-nstates:state_idxs(i)-1)=A(initial_idx+i-1);
%B matrix for i
Aeq(state_idxs(i):state_idxs(i)+nstates-1,input_idxs(i):input_idxs(i)+ninputs-1)=B(initial_idx+i-1);
end
end
function [Lb,Ub]=bound_cons(initial_idx,U_ref,npred,input_range,nstates,ninputs)
%time_idx is the index along uref the initial condition is at
xsize=(npred+1)*nstates;
usize=npred*ninputs;
Lb=[];
Ub=[];
for j=1:ninputs
Lb=[Lb;input_range(j,1)-U_ref(j,initial_idx:initial_idx+npred-1)];
Ub=[Ub;input_range(j,2)-U_ref(j,initial_idx:initial_idx+npred-1)];
end
Lb=reshape(Lb,[usize,1]);
Ub=reshape(Ub,[usize,1]);
Lb=[-Inf(xsize,1);Lb];
Ub=[Inf(xsize,1);Ub];
end
function dzdt=kinematic_bike(t,x,U,T)
%constants
Nw=2;
f=0.01;
Iz=2667;
a=1.35;
b=1.45;
By=0.27;
Cy=1.2;
Dy=0.7;
Ey=-1.6;
Shy=0;
Svy=0;
m=1400;
g=9.806;
%generate input functions
delta_f=U(1);
F_x=U(2);
%slip angle functions in degrees
a_f=rad2deg(delta_f-atan2(x(4)+a*x(6),x(2)));
a_r=rad2deg(-atan2((x(4)-b*x(6)),x(2)));
%Nonlinear Tire Dynamics
phi_yf=(1-Ey)*(a_f+Shy)+(Ey/By)*atan(By*(a_f+Shy));
phi_yr=(1-Ey)*(a_r+Shy)+(Ey/By)*atan(By*(a_r+Shy));
F_zf=b/(a+b)*m*g;
F_yf=F_zf*Dy*sin(Cy*atan(By*phi_yf))+Svy;
F_zr=a/(a+b)*m*g;
F_yr=F_zr*Dy*sin(Cy*atan(By*phi_yr))+Svy;
F_total=sqrt((Nw*F_x)^2+(F_yr^2));
F_max=0.7*m*g;
if F_total>F_max
F_x=F_max/F_total*F_x;
F_yr=F_max/F_total*F_yr;
end
%vehicle dynamics
dzdt= [x(2)*cos(x(5))-x(4)*sin(x(5));...
(-f*m*g+Nw*F_x-F_yf*sin(delta_f))/m+x(4)*x(6);...
x(2)*sin(x(5))+x(4)*cos(x(5));...
(F_yf*cos(delta_f)+F_yr)/m-x(2)*x(6);...
x(6);...
(F_yf*a*cos(delta_f)-F_yr*b)/Iz];
end
%% nonlinear opt functions
function [lb, ub] = bounds(start_idx, end_idx)
load('TestTrack.mat');
load('reftrack_info.mat');
@@ -361,6 +467,8 @@ function [g, h, dg, dh] = nonlcon(z)
end
%% linearization functions
function dzdt=bike(x,U)
%constants
Nw=2;