A New Method of Improving Low-Speed Performance of Variable Speed Hydraulic Systems: By Leaking Parallel Valve Control

Ding, Haigang; Zhao, Jun

doi:10.1155/2014/967373

Cited by 7 publications

(7 citation statements)

References 11 publications

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“…When the PDV is closed, and Q l0 , Q r0 , K cl and K cr are zero in Equations (11) and (12), the LPVC mode and RPVC mode will switch to the VSPC mode, and its open-loop dynamic equation is [1,2,20]…”

Section: Valve-pump Parallel Control Motor Linkmentioning

confidence: 99%

“…Figure 6 also shows that the response in the RPVC mode will be further improved by raising the supply pressure P s . As known, the open-loop gain increase will accelerate the system response, and open-loop gains K 3 are proportional to flow gains K vr according to Equation (20) and the flow gain of PDV in the replenishing status is given by K vr ¼ C sv ffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi P s À P h p in Equation(6), hence the raising P s will increase K vr and K 3 and then will accelerate the dynamic response. Figure 7 shows influences of load variation on the total leakage coefficient when keeping the inputs of pump and valve constant (u p = 6V, u l = ¡4V, u r = 4V).…”

Section: In Open-loop Controlmentioning

confidence: 99%

“…There are two control schemes: replenishing parallel valve control (RPVC) and leaking parallel valve control (LPVC), where a control valve could, respectively, work in the replenishing status and leaking status to regulate rapidly the system flow. In the valve-pump combined control system, RPVC is applied to achieve disturbance rejection at high speed, while the LPVC is applied to improve low-speed performance [20,21]. In this paper, the RPVC and LPVC are applied to improve the dynamic response of pump control systems while retaining a comparatively high efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic characteristic analysis of replenishing/leaking parallel valve control systems

Ding

Zhao

2017

Automatika

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To improve the dynamic response of traditional pump control systems, this paper proposes two new control schemes: replenishing parallel valve control (RPVC) and leaking parallel valve control (LPVC). A parallel valve control system using the two control schemes is designed, and its system parameters, control performances and efficiency are analysed and verified by simulation and experiments. Compared to the pump control system, the proposed system has larger damping ratios which vary widely with operating points, and has lower velocity stiffness due to the increase of total leakage coefficients. Both the LPVC and RPVC could contribute to the dynamic response improvement. RPVC is preferred over LPVC because of more stable damping ratios and higher speed stiffness, and these advantages could be further improved by increasing the supply pressure of the control valve, but the LPVC scheme costs lower due to the unnecessary oil supply for the control valve. During the control process, the valve works at a low flow rate, but the pump provides the majority of the system flow, so two parallel valve control systems still have relatively high energy efficiency with rapid response. Therefore, the RPVC and LPVC will enrich the control mode of hydraulic systems.

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Section: Valve-pump Parallel Control Motor Linkmentioning

confidence: 99%

Section: In Open-loop Controlmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic characteristic analysis of replenishing/leaking parallel valve control systems

Ding

Zhao

2017

Automatika

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“…In order to improve the pump control system's performance while keeping its high energy savings, some researchers combined the valve control and pump control methods [11]. Zhao et al [12] put forward a new control mechanism of valve-pump paralled variable structure control which could be accommodated between valve control and pump control to meet the control requirements, and concluded that the overall characteristic of the variable speed pump control system could be significantly improved.…”

Section: Introductionmentioning

confidence: 99%

Control Performance Improvement of Hydro-Viscous Clutch Based on Fuzzy-PID Controller

et al. 2021

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As a rotational speed controller, a hydro-viscous clutch (HVC) is usually used in the constant pressure water supply system to maintain the needed water pressure constant. However, when the hydro-viscous clutch is working, it often suffers from the problem of output rotational speed fluctuation since the spool of proportional relief valve can easily get stuck. Consequently, water pressure will fluctuate too. A special pump control system of HVC was proposed based on the Fuzzy-PID controller for the purpose of reducing the fluctuation rate. The MATLAB simulation was carried out according to the mathematical model and the results show that the Fuzzy-PID control strategy is superior to traditional PID control. The corresponding experiment was performed and the result indicate that through applying the Fuzzy-PID controller based pump control system, the rotational output speed fluctuation of HVC can be inhibited from ±60π to ±6π rad/min, and the water pressure fluctuation is dropped from ±0.1 to ±0.002 MPa.

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“…However, almost all hydrostatic pumps have high friction losses, strong wear and often also high volumetric losses at speeds below 500 rpm. While there have been efforts to work around these minimum speed limitations of pumps, they typically depend on introducing new throttling losses via a variable leakage path [5,6].…”

Section: Introductionmentioning

confidence: 99%

Benchmarking the performance of hydrostatic pumps

Mommers¹,

Achten²,

Achten³

et al. 2021

Linköping Electronic Conference Proceedings

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In search for sustainable and clean solutions, the hydraulic industry is forced to develop more efficient alternatives to traditional systems. For mobile applications, battery driven machines are becoming an essential solution. But, electric driven hydraulic systems set completely different demands than classical systems. Since batteries are expensive and bulky, it is no longer acceptable that the majority of the battery stored energy is lost in the hydraulic system. One of the promising solutions for efficiency increase is the application of electrohydraulic actuators (EHAs). Aside from all the inherent control advantages, EHAs deliver energy to each load on demand. This makes them much more efficient than current valve controlled systems, at least in principle. In practice, EHAs require both low and high-speed operation of pumps. Almost all hydrostatic pumps have high friction losses, strong wear and often also high volumetric losses at speeds below 500 rpm. Additionally, it is obvious that the pumps must have the highest efficiency possible. Given these constraints and demands it is understandable that information is needed about the performance of pumps and motors. In the past years, Innas has measured and tested several positive displacement machines and published a comprehensive report about these measurements. This paper will analyse the outcome of the test results, with a special focus on the application in EHAs.

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A New Method of Improving Low-Speed Performance of Variable Speed Hydraulic Systems: By Leaking Parallel Valve Control

Cited by 7 publications

References 11 publications

Dynamic characteristic analysis of replenishing/leaking parallel valve control systems

Dynamic characteristic analysis of replenishing/leaking parallel valve control systems

Control Performance Improvement of Hydro-Viscous Clutch Based on Fuzzy-PID Controller

Benchmarking the performance of hydrostatic pumps

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