Thank you for your reply.

My program are as follows:

detaT=0.5; % interval of time

T=60; % total time

NNN=T/detaT; %number of intervals

Vmax=50; %the max velocity of UAV

Vmin=14; %the min velocity of UAV

cvx_begin

expression B;

variable qn(2,NNN);

variable vn(2,NNN);

variable an(2,NNN);

for j=1:NNN

ee(j)=pow_pos(norm(vn(:,j)),3);

ee2(j)=sum_square_abs(an(:,j))/g^(2);

B=B+ee(j)+ee2(j);

end

maximize(B);

subject to

for t=1:NNN

if(t==1)

(qn(1,1)-x0)^(2)+(qn(2,1)-y0)^(2)<=(Vmax*detaT)^(2);*

qn(:,t)=[x0;y0];

vn(:,t)=[0;30];

else

(qn(1,t)-qn(1,t-1))^(2)+(qn(2,t)-qn(2,t-1))^(2)<=(VmaxdetaT)^(2);

qn(:,t)=qn(:,t-1)+vn(:,t-1)*detaT+0.5*an(:,t-1)*power(detaT,2);

vn(:,t)=vn(:,t-1)+an(:,t-1)*detaT;

end

end

cvx_end

When the program run to cvx_end, it shows the error. Actually, i used ‘expression’ instead of ‘variable’ to allow the coordinate and velocity be assigned. Then the program ran out without error but with a NaN or -Inf results.

In my question, i need obtain a optimal location and velocity. In my opinion, location and velocity can’t be declared as expression, they must be variables.

Hope you can answer my doubts.