Question

求高手给看看MATLAB中的一个程序怎么运行不了啊

%PID Controller
clear all;
close all;

ts=0.001;
sys=tf(5.235e005,[1,87.35,1.047e004,0]);
dsys=c2d(sys,ts,'z');
[num,den]=tfdata(dsys,'v');

u_1=0.0;u_2=0.0;u_3=0.0;
y_1=0.0;y_2=0.0;y_3=0.0;
x=[0,0,0]';
error_1=0.0;
for k=1:1:500
time(k)=k*ts;

S=3;
if S==1
kp=0.50;ki=0.001;kd=0.001;
rin(k)=1;
else if S==2
kp=0.50;ki=0.001;kd=0.001;
rin(K)=sign(sin(2*2*pi*k*ts));
else if S==3
kp=1.5;ki=1.0;kd=0.01;
rin(k)=0.5*sin(2*2*pi*k*ts);
end

u(k)=kp*x(1)+kd*x(2)+ki*x(3);
if u(k)>=10
u(k)=10;
end
if u(k)<=10
u(k)=-10;
end
yout(K)=-den(2)*y_1-den(3)*y_2-den(4)*y_3+num(2)*u_1+num(3)*u_2+num(4)*u_3;

error(k)=rin(k)-yout(k);

u_3=u_2;u_2=u_1;u_1=u(k);
y_3=y_2;y_2=y_1;y_1=yout(k);

x(1)=error(k);
x(2)=(error(k)-error_1)/ts;
x(3)=x(3)+error(k)*ts;

error_1=error(k);
end
figure(1);
plot(time,rin,'b',time,yout,'r');
xlabel('time(s)'),ylabel('rin,yout');
运行后出现这样的问题 ??? Error: File: Untitledlizi.m Line: 14 Column: 1
At least one END is missing: the statement may begin here.

Answer 1

elseif 写错了，没有空格