I have the system below
\begin{align} \ddot{\varphi } &=\frac{ \tau_e -m_P.R.\ddot{\alpha}.l.\cos\alpha+m_P.R.\dot{\alpha}^2.l.\sin\alpha-C_D.\pi.R^5.\rho.\dot{\varphi}^2}{J_B.R^2}\\ \ddot{\alpha}&=\frac{\tau - m_P.R.\ddot{\varphi}.l.\cos\alpha-m_p.g.l.\sin\alpha}{m_P.l^2} \end{align}
when I tried linearized that system I always get something with the form:
$\dot{x}=Ax+Bu+\text{constants}$
where $x$ is the state variables. $x=[\alpha, \varphi, \dot{\alpha}, \dot{\varphi}]$
I'm kind stuck to linearize the system to get the space state. I'm trying to linearize at $\alpha=\pi/4,\dot{\alpha}=0,\varphi=0,\dot{\varphi}=\bar{\dot{\varphi}}, \ddot{\varphi}=0$ using Taylor expansion. $\bar{\dot{\varphi}}$ is the mean angular velocity.
I need something in the form $\dot{x}=Ax+Bu$ without the constants.