Used or reproduced accurately follow a process of feedback control systems. Also known as the servo system. In many cases, specifically refers to a servo system control amount (the amount of output of the system) is a mechanical displacement or displacement velocity and acceleration feedback control system, the effect of the mechanical displacement of the output displacement (or angle) to accurately track the input ( or corner). Structures and other forms of feedback control system of the servo system is no difference in principle. Initially autopilot servo system for ships, artillery command and control instrument, then gradually extended to many areas, especially automatic lathes, antenna position control, missile and spacecraft guidance and so on. Using the servo system is mainly to achieve the following several purposes: ① small power command signal to control the power load. Gun control and rudder control is a typical example. ② In the absence of a mechanical connection, the input shaft is controlled by a remotely located output shaft to achieve remote synchronous transmission. ③ the output mechanical displacement accurately track signals, such as recording and indicating instruments and so on. The main indicators to measure the performance of servo systems have bandwidth and accuracy. Referred to the bandwidth of the bandwidth by the system to specify the frequency response characteristics, to reflect the fast tracking servo system. The larger the bandwidth, the better fast. Bandwidth of the servo system is mainly limited by the control object and the inertia of the actuator. Inertia, the more narrow bandwidth. General servo system bandwidth of less than 15 Hz, the bandwidth of the servo system of large equipment in the 1 to 2 Hz or less. Since the 1970s, due to the development of the torque motor and high sensitivity tacho, the servo system to achieve a direct drive, get rid of or reduce the nonlinear factors backlash and elastic deformation, so that the bandwidth of 50 Hz, and successfully applied In the long-range missiles, satellites, precision instruments and other places of command. The accuracy of the servo system is mainly determined by the accuracy in the measurement element. Thus, in the servo system must be measured with high precision components such as precision potentiometers, selsyn and rotary transformers. In addition, it may take additional steps to improve the accuracy of the system, such as the measuring element (eg selsyn) measurement axis and connected through reducer shaft, so that the shaft angle is amplified to increase the relative measurement accuracy. With this program the servo system is called coarse precision measuring systems or dual-channel systems. By measuring the angle line reducer shaft engaged with said fine reading channel, direct access to the spin axis of the goniometer line called coarse reading passage. Servo system according to the type of drive components can be divided into mechanical and electrical servo systems, hydraulic servo systems and pneumatic servo system.

keywords: St. Ling, Ling St. electromechanical, LSPTC, servo systems, feedforward control system,