Issue about accel of IMU

[ddliu365]

Hi, folks,

I am wondering if we ignored one item while calculating the IMU accel here.

$$\ddot{p} = \dot{v}_B + \dot{w}_B \times p + w_B\times v_B + w_B\times( w_B \times p)$$

imu_linacc = (
            self.base_linacc
            + np.cross(self.base_angacc, rot_base_to_world @ self.r_base_to_imu)
            **+ np.cross(self.base_angvel, self.base_linvel)**
            + np.cross(
                base_angvel,
                np.cross(base_angvel, rot_base_to_world @ self.r_base_to_imu),
            )
        )