Injection Molding Process Control of Servo–Hydraulic System

Lin, Che-Yi; Shen, Fang; Wu, Kuo Tsai; Lee, Huei Huang; Hwang, Sheng-Jye

doi:10.3390/app10010071

Cited by 9 publications

(5 citation statements)

References 7 publications

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“…Theorem 1. According to the disturbance observer (12), if d is bounded, the disturbance estimation error dis bounded and will converge exponentially to a sphere centered at the origin.…”

Section: Disturbance Observermentioning

confidence: 99%

“…In general, two kinds of hydraulic system configurations are used for these applications. One feasible method is to regulate the supply flow to the cylinder chamber by using an electrohydraulic servo/proportional valve [1,[11][12][13][14][15], which enables satisfactory dynamic behavior. Another approach is to regulate flow using a variable flow pump; this solution offers better energy efficiency [16], but the system bandwidth is restricted by the response speed of the pump, in which the moving parts' inertia is much larger than that of the servo/proportional valve.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Novel Reference Governor for Disturbance Observer-Based Load Pressure Control in a Dual-Actuator-Driven Electrohydraulic Actuator

et al. 2022

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In real-world applications, hydraulic pressure control performance is influenced by model uncertainties, the control bandwidths of valves and pumps, and deviations from the linear working region. To overcome the aforementioned obstacles, a novel reference governor for disturbance observer (DOB)-based load pressure control is proposed in this paper for a dual-actuator-driven electrohydraulic cylinder. First, a control-oriented model for load pressure control was developed. On the basis of this, a nonlinear DOB-based feedback controller, as well as a mid-range control architecture for the variable displacement pump and proportional valve, was fabricated so that the performance degradation caused by the pump’s slow responses and imprecise system parameters is suppressed. Specifically, this controller is augmented by a novel smooth reference governor, which modifies the load pressure command in the pressure transition periods to guarantee that the actuator’s constraints are not violated. Another merit of the novel reference governor is that it ensures a smooth trajectory transition, and therefore, unmodeled high-frequency plant dynamics will not be invoked. Case studies were carried out to verify the effectiveness of the proposed control approach. The study results show that the approach can significantly enhance the hydraulic system’s pressure tracking performance.

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“…Theorem 1. According to the disturbance observer (12), if d is bounded, the disturbance estimation error dis bounded and will converge exponentially to a sphere centered at the origin.…”

Section: Disturbance Observermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Novel Reference Governor for Disturbance Observer-Based Load Pressure Control in a Dual-Actuator-Driven Electrohydraulic Actuator

et al. 2022

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“…Chen et al [ 21 ] mentioned that using a high sampling rate controller can make the servo-hydraulic system more stable. Lin et al [ 22 ] used a servo-hydraulic system to investigate the performance (response time) of the proposed system in terms of its speed control (filling process), pressure control (packing process), and V/P switchover point control ( V/P transition). The results show that a pull-back distance of 1 mm can be achieved using a sampling frequency of 1000 Hz.…”

Section: Introductionmentioning

confidence: 99%

Optimize Injection-Molding Process Parameters and Build an Adaptive Process Control System Based on Nozzle Pressure Profile and Clamping Force

Liou

Cheng

et al. 2023

Polymers

Self Cite

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The injection-molding process is a non-linear process, and the product quality and long-term production stability are affected by several factors. To stabilize the product quality effected by these factors, this research establishes a standard process parameter setup procedure and an adaptive process control system based on the data collected by a nozzle pressure sensor and a tie-bar strain gauge to achieve this goal. In this research, process parameters such as the V/P switchover point, injection velocity, packing pressure, and clamping force are sequentially optimized based on the characteristics of the pressure profile. After the optimization process, this research defines the standard quality characteristics through the optimized process parameters and combines it with the adaptive process control system in order to achieve the purpose of automatic adjustment of the machine and maintain high-quality production. Finally, three different viscosity materials are used to verify the effectiveness of the optimization procedure and the adaptive process control system. With the system, the variation of product weight was reduced to 0.106%, 0.092%, and 0.079%, respectively.

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“…Servo-hydraulic systems are essential operating units in many industrial applications due to their high precision, low operating temperatures, low noise, and good repeatability. Moreover, servo-hydraulic systems can attain energy savings of up to 70% compared to other conventional hydraulic systems [1]. However, these systems are characterized by their highly complex and nonlinear dynamics, and hence, they require precise and powerful controllers to cope with the complexity and nonlinearity of such systems.…”

Section: Introductionmentioning

confidence: 99%

“…As the tuning method, the authors used the Ziegler-Nichols approach to optimize the gains of the PID controller. In another work, Lin et al [1] proposed a method to control the velocity-pressure switchover point in a servo-hydraulic system using the PID controller. As an intelligent tuning method, Mahdi [3] used the ant colony optimization to find the optimal settings for the PID controller's gains to control a servo-hydraulic system whose model was linearized to  ISSN: 2502-4752 simplify the control design procedure.…”

Section: Introductionmentioning

confidence: 99%

Control of a servo-hydraulic system utilizing an extended wavelet functional link neural network based on sine cosine algorithms

Mahdi

Lutfy

2022

IJEECS

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Servo-hydraulic systems have been extensively employed in various industrial applications. However, these systems are characterized by their highly complex and nonlinear dynamics, which complicates the control design stage of such systems. In this paper, an extended wavelet functional link neural network (EWFLNN) is proposed to control the displacement response of the servo-hydraulic system. To optimize the controller's parameters, a recently developed optimization technique, which is called the modified sine cosine algorithm (M-SCA), is exploited as the training method. The proposed controller has achieved remarkable results in terms of tracking two different displacement signals and handling external disturbances. From a comparative study, the proposed EWFLNN controller has attained the best control precision compared with those of other controllers, namely, a proportional-integralderivative (PID) controller, an artificial neural network (ANN) controller, a wavelet neural network (WNN) controller, and the original wavelet functional link neural network (WFLNN) controller. Moreover, compared to the genetic algorithm (GA) and the original sine cosine algorithm (SCA), the M-SCA has shown better optimization results in finding the optimal values of the controller's parameters.

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Injection Molding Process Control of Servo–Hydraulic System

Cited by 9 publications

References 7 publications

A Novel Reference Governor for Disturbance Observer-Based Load Pressure Control in a Dual-Actuator-Driven Electrohydraulic Actuator

A Novel Reference Governor for Disturbance Observer-Based Load Pressure Control in a Dual-Actuator-Driven Electrohydraulic Actuator

Optimize Injection-Molding Process Parameters and Build an Adaptive Process Control System Based on Nozzle Pressure Profile and Clamping Force

Control of a servo-hydraulic system utilizing an extended wavelet functional link neural network based on sine cosine algorithms

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