A Study On Film Transmission Control System In Space Camera

Film transmission machine consists of film supply system,film receipt system and film measuring system.Both film supply system and film receipt system are tension servo systems.Film measuring system is system of controlling film length,this three systems are independent and relative one another.Film measuring operation of film measuring system disturbs both film supply system and film receipt system as an extra-interference and it is very heavy.Main mission of film measuring system is transmitting film of constance length in limited time.Film measuring system is drove by stepping motor,so increasing and decreasing frequency principle for stepping motor is analyzed,and design the stepping motor velocity curve by the analysis conclusions.Heavy interference,changeable variables and load are the characteristics of film supply system and film receipt system.Resolutions for these problems are emphasized in this paper.As usual,the effective method to solve the heavy interference in low frequency and the changeable load is compound control for disturbance compensation.A method to realize the compound control for disturbance compensation is put forward in this paper.The basic thought of the method is that:obtain the ideal compensation signal No(t),and input the compensation signal No(t) to the tension servo system when the system is disturbed.Compensation signal No(t) includes the following variables:delay time,compensation period,compensation time,compensation data .Methods and procedures to obtain the compensation variables are discussed in detail in this paper.Two specific means are available to realize the compensation control,and discussed in detail in this paper.In one means,the method is needed to calculate the compensation variables in real time, the linear interpolation is used here. The experiences prove that those methods are effective to improve the tension control accuracy.