Development Of Force-sensor And Heat-sensor Editorial Storage Devices For Recoverable Spacecraft

With the development of space technology,various environmental parameters of spacecraft need to be acquired and stored.Thus,data acquisition and storage become the essential technique for space missions.Multi-channel,high speed,high precision and miniaturization are the development trends in future space data acquisition and storage.To meet the requirements of the engineering parameters acquisition and storage of a returnable spacecraft,an acquisition and storage device is developed in this thesis,which is capable of acquiring and store various types of sensors,including mechanical sensors(ICP type,charge type,voltage type),thermocouple,thermistor sensors,etc.It can also frame the acquired date and store the data in in NAND FLASH,and replay the stored data through the Ethernet interface.The CPU of the main control module manages the entire device.In the data acquisition and process module,an FPGA chip is adopted to perform data storage and playback management for each sensor.The sensor module takes advantage of modular design and integrates the functions of signal conditioning,data acquisition and framing into a single module for the same type of sensors,which is convenient for system expansion.In addition,a general mechanical sensor signal conditioning circuit is designed,suitable for signal conditioning of three types of conventional mechanical sensors.Besides,the compensation of the thermocouple cold junction is also studied.Thermistors are utilized for temperature compensation for the cold end,and the influence of the position choice of the cold end temperature test point is analyzed by experiments.The code of the ARM chip is realized using C language,which achieves the function of the real-time monitoring of the front panel,the distribution of orders(including start and stop of acquisition,flash erasure,data playback,etc.),and data playback from flash through the Ethernet interface using TCP/IP protocol.FPGA is programmed using VHDL language.Setting the sampling frequency according to the Nyquist sampling theorem,FPGA can realize the data acquisition process.As FPGA is capable of bad block management,the bad block table is established based on the method of bad block skip.Finally the playback data is further analyzed using MATLAB.System-level verification of the device function is done in laboratory,and field tests are also completed.Test results indicate that the acquisition and storage device can satisfy the required performance indexes.Finally,a summary is made for the design and further development of the device is discussed.