“…It is not possible to find a report generic about the friction force for the traditional cylinder. However, considering the state of art of manufacturing technology for cylinder, it is certain that the level of friction force of a multi-chamber cylinder is higher than that of traditional cylinder, 10–14 which needs to be considered for the secondary control of digital hydraulic systems. Figure 14.Friction force according to cylinder state (5 mm/s).Figure 16.Friction force according to cylinder state (40 mm/s).Figure 17.Friction shell in digital hydraulics.Figure 18.Friction force with cylinder mode 1.…”
Section: Resultsmentioning
confidence: 99%
“…Yanada et al 11 showed unsteady friction characteristics of hydraulic actuator. Muraki et al 12 performed a laboratory simulation for stickslip phenomena on the hydraulic cylinder of a construction machine. Owen and Croft 13 tried to reduce the stick-slip friction in hydraulic actuators.…”
This paper deals with the issue of defining friction characteristics of a multi-chamber cylinder for digital hydraulics. Using a multi-chamber cylinder under a set of supply pressures, friction characteristics are experimentally investigated for a range of velocity according to load conditions. A binary digit-based pressure e.g., high pressure or low pressure has been applied to each chamber. The friction force is measured based on the equation of motion using measured values of the pressures in the chambers of the multi-chamber cylinder and the position of the piston. As a mechanism to load the multi-chamber cylinder, a 1-Degree of Freedom (DOF) boom mockup mimicking a medium-sized mobile machine boom has been constructed. Then it has been utilized to test the motion of the cylinder under different mass–load conditions. It is shown that the cylinder states do not dominantly affect the friction force of a multi-chamber cylinder, comparing the effect of other parameter such as mass load and velocity, which is expected to be useful for the secondary control of digital hydraulic systems.
“…It is not possible to find a report generic about the friction force for the traditional cylinder. However, considering the state of art of manufacturing technology for cylinder, it is certain that the level of friction force of a multi-chamber cylinder is higher than that of traditional cylinder, 10–14 which needs to be considered for the secondary control of digital hydraulic systems. Figure 14.Friction force according to cylinder state (5 mm/s).Figure 16.Friction force according to cylinder state (40 mm/s).Figure 17.Friction shell in digital hydraulics.Figure 18.Friction force with cylinder mode 1.…”
Section: Resultsmentioning
confidence: 99%
“…Yanada et al 11 showed unsteady friction characteristics of hydraulic actuator. Muraki et al 12 performed a laboratory simulation for stickslip phenomena on the hydraulic cylinder of a construction machine. Owen and Croft 13 tried to reduce the stick-slip friction in hydraulic actuators.…”
This paper deals with the issue of defining friction characteristics of a multi-chamber cylinder for digital hydraulics. Using a multi-chamber cylinder under a set of supply pressures, friction characteristics are experimentally investigated for a range of velocity according to load conditions. A binary digit-based pressure e.g., high pressure or low pressure has been applied to each chamber. The friction force is measured based on the equation of motion using measured values of the pressures in the chambers of the multi-chamber cylinder and the position of the piston. As a mechanism to load the multi-chamber cylinder, a 1-Degree of Freedom (DOF) boom mockup mimicking a medium-sized mobile machine boom has been constructed. Then it has been utilized to test the motion of the cylinder under different mass–load conditions. It is shown that the cylinder states do not dominantly affect the friction force of a multi-chamber cylinder, comparing the effect of other parameter such as mass load and velocity, which is expected to be useful for the secondary control of digital hydraulic systems.
“…It consists of causing vibrations by changing the friction force. In the article [ 60 ], it is noted that the phenomenon was related to the transfer of carbon monoxide from carbon steel to the sealing surfaces. This leads to noise and accelerates the wear of sealing elements.…”
Section: Failures Of Hydraulic Actuatorsmentioning
The article is an overview of various materials used in power hydraulics for basic hydraulic actuators components such as cylinders, cylinder caps, pistons, piston rods, glands, and sealing systems. The aim of this review is to systematize the state of the art in the field of materials and surface modification methods used in the production of actuators. The paper discusses the requirements for the elements of actuators and analyzes the existing literature in terms of appearing failures and damages. The most frequently applied materials used in power hydraulics are described, and various surface modifications of the discussed elements, which are aimed at improving the operating parameters of actuators, are presented. The most frequently used materials for actuators elements are iron alloys. However, due to rising ecological requirements, there is a tendency to looking for modern replacements to obtain the same or even better mechanical or tribological parameters. Sealing systems are manufactured mainly from thermoplastic or elastomeric polymers, which are characterized by low friction and ensure the best possible interaction of seals with the cooperating element. In the field of surface modification, among others, the issue of chromium plating of piston rods has been discussed, which, due, to the toxicity of hexavalent chromium, should be replaced by other methods of improving surface properties.
“…The flow equation of the valve, the cylinder’s flow continuity equation, and the cylinder and loads equilibrium equation are needed to build the math model of the hydraulic servo system. 5–8…”
Section: Building the Math Model Of The Hydraulic Systemmentioning
confidence: 99%
“…The flow equation of the valve, the cylinder's flow continuity equation, and the cylinder and loads equilibrium equation are needed to build the math model of the hydraulic servo system. [5][6][7][8] Using the unsymmetrical proportion valve to control the unsymmetrical cylinder can decrease the changes of the loads and the pressure pulsation when the cylinder is reversing. The schematic diagram is shown in Figure 2.…”
Section: Building the Math Model Of The Hydraulic Systemmentioning
The hydraulic rolling shear whose hydraulic system is researched in this article is designed based on the theory of rolling shear. This article builds the transfer function of the unsymmetrical valve controlling unsymmetrical cylinder system and gets the expressions of the flow gain and the flow pressure coefficients and then compares them with the system controlled by symmetric valve. After the theoretical analysis, this article compares the control effects between the unsymmetrical valve and symmetric valve with the simulation software HYVOS. The simulation declares that when the unsymmetrical cylinder is controlled by the unsymmetrical valve, its control voltage is one-third of that controlled by the symmetric valve. Using unsymmetrical valve to control the unsymmetrical cylinder is perfect and meets the demands of the rolling shears as shown by the data collected from the field.
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