哪位大佬解释一下为什么会出错？为什么？

smileqq

哪位大佬解释一下为什么会出错？为什么？

l1=80;l2=260;l3=300;l4=460;lde=400;
* i& G! {) R8 V! i) O9 gsyms x1 x2 x3 x4 l1 l2 l3 l4 lde s;
& ~6 o+ n$ u0 w, ?x1=0:10:360;
7 }( t" M: g, ~" u+ d* jx1=x1*pi/180;
eq1=l1*cos(x1)+l2*cos(x2)==180+l3*cos(x3);
eq2=90+l1*sin(x1)+260*sin(x2)==l3*sin(x3);
+ M, j5 r  ?  J5 G+ C3 n3 feq3=lde*cos(x3)+l3*cos(2*pi-x4)==s-180;
+ e( |  ]8 B- B$ Ueq4=lde*sin(x3)==l3*sin(2*pi-x4)+90;
5 G; S4 X- h( w& s[x2,x3,x4,s]=solve(x2,x3,x4,s);
8 a% j! D$ a5 j8 k0 y: e$ u错误使用 solve (line 279)
0 I% |0 l- f' p! n7 @* TInconsistent output with 4 variables for input argument with 3 variables.

NNNei256

不太懂

pulbieup

老老实实写循环，每步对一个phi值进行求解

• clear; clc;
• syms omega2 omega3
• L1 = 9; L2 = 25; L3 = 40; L8 = 37.48;
• omega1 = 0.4*pi;
• phi1Set = [0:pi/20:2*pi];
• Omega2 = zeros(size(phi1Set));
• Omega3 = zeros(size(phi1Set));
• for ii = 1:1:numel(phi1Set)
•     phi1 = phi1Set(ii);
•     phi8 = 0.914*pi;
•     A = 2*L3*(-L8*sin(phi8)+L1*sin(phi1));
•     B = 2*L3*(-L8*cos(phi8)+L1*cos(phi1));
•     C = -L1^2-L3^2-L8^2+L2^2+2*L1*L8*cos(phi1)*cos(phi8)+2*L1*L8*sin(phi1)*sin(phi8);
•     D = 2*L2*(-L8*sin(phi8)+L1*sin(phi1));
•     E = 2*L2*(-L8*cos(phi8)+L1*cos(phi1));
•     F = L1^2+L2^2+L8^2-L3^2-2*L1*L8*cos(phi1)*cos(phi8)-2*L1*L8*sin(phi1)*sin(phi8);
•     phi2 = 2*atan((D+sqrt(D.^2+E.^2-F.^2))./(E-F));
•     phi3 = 2*atan((A+sqrt(A.^2+B.^2-C.^2))./(B-C));
•     x = [-L2*sin(phi2),L3*sin(phi3);L2*cos(phi2),-L3*cos(phi3)];
•     y = omega1*[L1*sin(phi1),-L1*cos(phi1)];
•     omega = y/x;
•     eq1 = -L2*omega2*sin(phi2)+L3*omega3*sin(phi3)-L1*omega1*sin(phi1);
•     eq2 = L2*omega2*cos(phi2)-L3*omega3*cos(phi3)+L1*omega1*cos(phi1);
• sol  =  vpasolve([eq1,eq2],[omega2,omega3],[0,2*pi]);
•     Omega2(ii)  =  double( sol.omega2 );
•     Omega3(ii)  =  double( sol.omega3 );
• end
• plot(phi1Set,Omega2,'r-',phi1Set,Omega3,'b-','LineWidth',2);
  

5 K" u' d, J9 b' X

smileqq

pulbieup 发表于 2020-7-21 16:55
老老实实写循环，每步对一个phi值进行求解
9 D9 {) x# @' t/ E  F9 b

clear; clc;

8 P8 `$ a8 ^, m谢谢指导，知道了