model unknown的用法和样例：
例句
- Simulation results showed that the proposed approach could achieve the robust tracking of the unknown nonlinear system.
仿真结果表明，该方法能对模型未知仿射非线性系统实现鲁棒输出跟踪。 - The learning algorithm can effectively control the unstabl nonlinear system, even if the model of the system is not available and the learner has no a priori experience.
该学习算法在模型未知和没有先验经验的条件下，能通过自身神经网络的在线学习，有效控制不稳定的非线性系统。
