请教 S-function报错问题： during flag=3 call must be a real vector of length 2

编写了一个S—Function函数，三输入两输出，
报错：Output returned by S-function 'controller' in 'VehicleMathModel/S-Function' during flag=3 call must be a real vector of length 2
网上求解方法：
1、sizes.DirFeedthrough = 1; %输出与输入没有直接关系0
2、x0 = [0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;0.01;];
均无效
想请教还有别的解决方法吗