Abstract: According to the time-varying and nonlinear characteristics of the locomotive pneumatic brake force control，the Model-Free Adaptive Control（MFAC） approach is applied to the volume chamber pressure control，which directly determines the pneumatic brake force.The design of controller is model-free and needs no complex parameter tuning.Based directly on the input and output information of the system，the chamber pressure can be precisely obtained by Model-Free Algorithm.The model-free control is especially useful for real nonlinear systems whose model parameter are very difficult to be identified and time varying.The simulation control results show that the algorithm has such advantages as quick response，high control accuracy and good robustness for nonlinear systems.

Key words: universal model, Model-Free Algorithm（MFA）, volume-chamber pressure

摘要： 为实现对具有非线性、时变和多干扰等特性的机车气制动力的精确控制，提出一种基于无模型控制算法的容积压力控制方法。它不依赖控制系统参数数学模型，不需要复杂的人工参数整定即可控制时变、多变量等复杂过程，可以避免建模不精确带来的系统误差，实现对气室压力的精确控制。仿真试验表明，该系统具有响应快速、控制精确、适应能力强、控制稳定等优点。

关键词: 泛模型, 无模型算法MFA, 容积室压力