Matlab 如何以数值方式计算以下常微分方程组（使用ICs）

我试图解决以下5组一阶常微分方程

其中考虑的变量是tthaa0、tthaa1、φ、Δ和v，其余都是常数。初始条件（ICs）为：

我正在运行以下MATLAB代码（遵循与已解决示例中所示完全相同的步骤）

如注释中所述，代码在最后失败，表明初始条件无效

为什么提供的ICs是错误的？如何解决这个问题

 syms u(t) v(t) w(t) x(t) y(t) a b d G k %Note that u corresponds to the variable v (see #1), v to                
 \delta, w to \Theta_0, x to \Theta_1, y to \Phi and b to \dot a%

 ode1 = diff(w) + diff(y) == -k*x;
 ode2 = diff(x) == (k*w)/3 - (k*y)/3;
 ode3 = diff(v) + 3*diff(y) == i*k*u;
 ode4 = diff(u) == i*k*y - (b*u)/a;
 ode5 = (3*b*(diff(y) + (b*y)/a))/a == 4*G*a^2*d*pi*v - k^2*y + 16*G*a^2*d*pi*w;
 odes = [ode1; ode2; ode3; ode4; ode5]
 [uSol(t), vSol(t), wSol(t), xSol(t), ySol(t)] = dsolve(odes) %Code works, yielding quite "ugly" 
 answers. Next we introduce ICs%

 cond1 = x(0) - i*(u(0))/3 == 0;
 cond2 = v(0) - 3*w(0) == 0;
 cond3 = y(0) - 2*w(0) == 0;
 conds = [cond1; cond2; cond3];
 [uSol(t), vSol(t), wSol(t), xSol(t), ySol(t)] = dsolve(odes,conds) %Code breaks down, giving the 
 output "Invalid initial conditions"%