[ Eq(Derivative(x1, t), ((-1)*k10*k3*x1 + 1*k10*(k2 - k1*x3)*(1 - Piecewise((1, Gt(x3 - k2/k1, 0)), (0, True))))/k10),
  Eq(Derivative(x2, t), (1*k10*k4*x1 + (-1)*k10*k5*x2)/k10),
  Eq(Derivative(x3, t), (1*k10*k6*x2 + (-1)*k10*k7*x3)/k10) ]