Development Of Shift Control System Of MT Shift Test Bed Based On Embedded System

Manual transmission gear shift manipulator solve a lot of problems rely on manual shift,such as the time-consuming,laborious and the problem of unable to achieve consistent or specified force and speed when shifting the lever to a given gear.And is extensively used for shift operation on manual transmission test bench.The embedded system has the characteristics of flexible custom,the shift manipulator control system based on embedded system for the test bench can be configured flexibly and conveniently,and can be easily used in other areas where need automatic shift,after reconfigured the hardware and software.So it is meaningful to develop the shift manipulator based on embedded system.In this paper,the current commonly used shift manipulator control system was introduced,firstly.After the research of the existing manipulator control system used at home and abroad,a kind of manual transmission shift mechanical hand control system scheme based on embedded system was given,according to the requirement of the manual transmission shift experiment station.The scheme uses PC as the main controller,the embedded system as slave controller control the servo driver drive the electric cylinder,achieved a closed-loop controller by receiving the feedback position and force signals of a grating and a force sensor.PC and embedded system are connected with Ethernet,and the embedded system work as a server,receiving information form the PC and taking action.According to the functional requirements of the controller and the characteristics of embedded system,this paper completes the selection of the controller chip,circuit schematic diagram and the design of PCB.Schematic design comprises the crystal oscillator circuit,extended memory circuit,network PHY circuit,function selection switch,JTAG and USB interface,TF card,CAN bus and SPI interface,network interface and serial interface,I/O expansion,grating encoder interface,buttons and LED lights,force sensor interface,speed control output and power supply circuit.PCB design of the controller hardware is divided into two parts of the core board and expansion board,and they are connected through sockets.The core board uses 4 layers of PCB board,the expansion board uses 2 layers of PCB board,and all PCB board has poured copper on double side,and has good electrical performance.Using the JSON syntax defined the formats of network communication data,such as the date and time settings data,the gear information data,the shift control information data,the cyclic shifting control information data,the control instructions and the control information data.Configured the functions of the peripherals,and gave out their detail configuration parameters and the use methods.Gave out the configuration parameters and their use methods of the functional middleware software,including FATS,LwIP,FreeRTOS,USB_Device and Jansson.Defined the user interrupt routine,and the functions of these interrupt application.Programmed the function threads of the control system,including Ethernetif_set_link set link process,SD card data reading and writing process,information receiving and processing process,the automatic shift system control process,the automatic shift process,the manual shift process and the X,Y axis mechanical hand control process.And also verified the function of the controller.