Development And Research On Control Platform Of An Opposed Hydraulic Free Piston Engine

The progress of electronic control technology has a great role in promoting the development of the internal combustion engine industry.The fundamental difference between the modern and the traditional internal combustion engine is that it applies computer technology and modern control theory to optimize the working process of the engine.While as a guarantee,various optimization control experiments require fully functional and simple operating ECU development platform as well as measuring and calibration system.For this,an improved embedded real-time operating systems and multi-bus calibration platform have been developed on in-depth research of the OSEK/VDX operating system specifications and XCP calibration protocol.Further more the system has been applied to the research of opposed hydraulic free piston engine(OHFPE).An embedded real-time operation system called CORTEX-OSEK-ST,which is fully compatible with OSEK/VDX specification,is firstly developed.To meet the needs of practical application,CORTEX-OSEK-EX,as the extension of operating system,has been designed.Compared with CORTEX-OSEK-ST,memory management,time management mechanism are added and task management,event mechanism,resource management mechanism,message mechanism are improved in CORTEX-OSEK-EX.Finally,the operating system migration has been achieved on the NXP LPC4337 micro-controller and the instantaneity is tested.The results show that under the CPU operating frequency of 204 MHz case,task switching time is 6.327μs and interrupt response time is 0.38μs.The designed calibration platform is based on XCP protocol and can be used to communicate with calibration software separately by CAN bus,USB bus,Ethernet bus and WIFI network.The key technology in the design of synchronous data acquirement,block transmission mode,flash on-line programming is detailed descripted in this paper.Also,a calibration software called CorDesk based on Android mobile platform has been developed.The control method of TDC position and piston synchronization of OPHFPE is researched.The responses of the engine to force disturbance and set point change are studied using proportional-integral-derivative(PID)controller,simplified energy equation feed-forward and gray model-modified energy equation feed-forward.Gray model-modified energy equation feed-forward,along with PID,is found to provide satisfactory response performances in piston TDC position control.Synchronization was also studied.It was found that the piston motion on one side influences that of the other side through the gases trapped within the common combustion cylinder.An adequate synchronization of the compression stoke was presented by adjusting the high-pressure solenoid valves in combination with employing an asynchronous start mechanism.Finally,the designed free piston control strategy has been realized on the ECU platform,and the hardware in the loop test system has been setup.The feasibility of the control strategy and the stability of the ECU platform have been verified through this system.