New Locomotive Brake Control Unit Developed

The braking system is important to locomotive's running safety.As the automatic air brake JZ-7 and DK-1 can't satisfy the need of Da-Qin railway line's heavy haul freight train braking, ministry of railway has prepared to develop new generation locomotive braking system DK-2, the new type brake control unit is the key part of DK-2.The structures and functions of DK-2 braking system are introduced in detail and the requirement of DK-2 braking system is analyzed in this thesis. Based on above analyses, the scheme of new type brake control unit is proposed, in which the pc/104 control module is used as CPU and the new type brake control unit's hardware and software are designed.As the heavy haul freight train's formation is longer and weight is heavier than that of normal train, it is request to braking precision. In this thesis, the Pulse Width Modulation technique is used as controlling locomotive brake cylinder and equilibrium cylinder's air pressure accurately so as to braking accurately. As different locomotive braking systems have different characteristic parameters, the brake control unit should be adaptive to different braking system. The Fuzzy Self-adaptive PID is used in the brake control unit, it is tunning PID parameters real time based on error and variety rate of error at different moment.The design of hardware and software are introduced in detail in this thesis. The hardware of new type brake control unit is designed with modularization including CPU board, digital I/O boards, analogy I/O boards, PWM board and communication board. The ISaGRAF is used as programming software and is designed with modularization including logical control part, check-up itself part, fault diagnose part and communication part.At last, through some experiments on the DK-2 braking system show that the new type brake control unit achieve the goal,the scheme of new type locomotive brake control unit is in reason and the system's performance is all right, it can meets the need of heavy haul freight train.