Research of Control Strategy in the Large Electric Cylinder Position Servo System

Abstract

An ideal positioning response is very difficult to realize in the large electric cylinder system that is applied in missile launcher because of the presence of many nonlinear factors such as load disturbance, parameter variations, lost motion, and friction. This paper presents a piecewise control strategy based on the optimized positioning principle. The combined application of position interpolation method and modified incremental PID with dead band is proposed and applied into control system. The experimental result confirms that this combined control strategy is not only simple to be applied into high accuracy real-time control system but also significantly improves dynamic response, steady accuracy, and anti-interference performance, which has very important significance to improve the smooth control of the large electric cylinder.

Improved Linear Active Disturbance Rejection Control for Lever‐Type Electric Erection System with Varying Loads and Low‐Resolution Encoder

“…Based on (1) and (6), the simulation model can be built in Simulink. Moreover, the stair-step signals of the low-resolution encoder caused by quantization noise can be simulated by the block-"Quantizer"-using the round-to-nearest method, according to the resolution of encoder.…”

“…The maximum stroke of the electric cylinder is 0.3 m, the reduction ratio i is two, and the lead of ball screw L is 0.005 m. Changing S from 0 to 0.3, m and e can be calculated according to (3) and (5), respectively. Then, curve fitting is performed in MATLAB and the approximate polynomial expression is: = ( ) = 1.391 × 10 −9 3 − 5.863 × 10 −7 2 + 0.001763 − 0.005364 (6) where the units of m and e are both rad, the confidence bounds of the coefficients are 95%, the RMSE is 0.0049, and the SSE is 0.2419.…”

“…Time-varying integral adaptive sliding mode control [4] and flow-pressure compound control [5] have been adopted to control the hydraulic erection system. With the improvement of servo motor and drive mechanism, the electric cylinder can be used as the actuator in the electric erection system [6]. The erection system in this paper combines the singlestage electric cylinder with the lever-type erection mechanism, which can shorten the strokes and avoid shock.…”

Experiments and Simulation on a Late-Model Wind-Motor Hybrid Pumping Unit

“…Also, the compressibility of the oil should not be left out. In other words, the influence of the hydraulic pipeline and the internal volume of the pump or motor of the hydraulic system should be ignored, as should the influence of the lowpressure side pipeline pressure on the system, and the low-pressure side pipeline pressure should be regarded as zero [16,17]. The wind-motor hybrid power system is presented in the left part of Figure 1.…”

“…From Equations (24), (25), and (26), we see that the mechanical-hydraulic system efficiency is mainly affected by P h , n p , n m , P w-p , and P e . The speed of the pump, the hydraulic motor, and the electromotor is satisfied with Equation (17). The experimental coupling speed is 730 r/min.…”