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This paper aims to investigate the performance of a hydraulic actuator controlled by the novel system micro-independent metering (MIM). This analysis has been performed by comparing the models of two systems which are the traditional independent metering, that depends on poppet valve, and the new hydro-mechatronics system micro-independent metering, that relies on a stepped rotary flow control valve. In general, independent metering is a hydraulic control system which guarantees a separation between the meter-in and the meter-out of the hydraulic actuator. A Valvistor valve, a special type of Poppet valves, was developed to be embedded into the independent metering (IM) system. This valve has controllability and stability shortcomings which prevent the system from spreading in the industrial applications. The Valvistor valve performance is highly affected by the fluid disturbances because the fluid is considered as a part of its control elements. A stepped rotary flow control valve has been developed to control hydraulic flow rate. The valve composed of a rotary orifice attached to a stepper motor. Using this valve instead of the traditional poppet type has led to a new configuration, that is termed by micro-independent metering. This form improves the hydraulic cylinder velocity performance by rejecting the fluid disturbances effect on the control circuit.

The subject of this paper is the review of advanced technology used in hydraulic systems. The technology in question is termed Independent Metering (IM); this is used in hydraulically driven mobile machinery, such as agricultural, construction, municipal, and forestry vehicles. The idea behind the concept is to modify the connection between the actuator, which could be a cylinder or a motor, and a flow control valve. Traditionally, spool hydraulic valves were used to control the fluid flow into and out of hydraulic actuators. This keeps the meter-in and the meter-out of the actuator mechanically connected due to the construction of these valves. This connection makes the control system blind to pressure changes in one of the hydraulic chambers in the actuator. This, in turn, reduces the overall system controllability. It also increases energy losses, especially under an overrunning load. These two main weaknesses led researchers to break this mechanical connection and get into a new technology with different characteristics. The proposed technology was called Independent Metering. New and more complex control techniques can now be applied to the hydraulic systems using this technology that were not possible before or could be applied to more conventional servo design. This paper reviews Independent Metering (IM) and the technologies used or developed in this field to date. The paper reviews the state of art hydraulic technologies and indicates the links between them and IM. It also reviews the different types of hydraulic valves used when implementing IM. This review also discusses some control algorithms, IM layouts, IM challenges, and identifies where further improvements may be achieved.

This paper investigates the driving techniques for a novel stepped rotary flow control valve which has been developed for a hydraulic Independent Metering (IM) control system. This valve has promising features such as observed controllability and stability. Its main structure is composed of a stepper motor coupled directly to a rotary orifice. The rotation of the stepper motor changes the orifice opening area and therefore the rate of the fluid flow. Two main techniques have been used to drive the stepper motor which are the full step and the micro-step rotary movements of the stepper motor and with it the rotary control orifice. Investigation of the relationship between these driving techniques and the dynamic performance of the valve is necessary to develop a control algorithm for this new IM configuration. This investigation is based on the mathematical model of the valve, and indicates that the driving signals have a different effect on the dynamical performance of the valve. For example, the rest points using the full step technique affects the friction torque produced by the rotary orifice.

This paper presents a control algorithm for a novel Mechatronics Electro-hydraulic Driving System, Micro-Independent Metering. The main idea of the independent metering is a separated control of the hydraulic actuator ports which are the meter-in and the meter-out. IM technique configuration relies upon different types of valves, especially on poppet valves. As these valves have stability limitations, a novel stepped rotary valve was developed to configure a novel IM form. This form is termed as micro-independent metering due to the activation technique of the valve. A novel algorithm was developed to control this new configuration. The algorithm implements the rules of the independent metering using the new valve. It is able to detect the different operation modes and make a real time changing between them. Also, it activates the enhanced performance technique which was especially developed for this new configuration. The paper includes the mathematical analysis of the developed algorithm and its State-flow representation. Also, it includes the simulation of the system performance and the effect of MIM on the cylinder velocity.

This paper presents the results of numerical and experimental performance evaluation of the rotary tubular spool valve. The aim of this work is to develop further the novel design of the tubular spool valve by confirming validity of the simulation model and its results, thereby proving the valve’s potential to represent a feasible and more efficient alternative to conventionally used spool valves avoiding the use of more expensive two stage valve configurations. In this research the valve performance is assessed through numerical modelling and experimental studies of metering and pressure loss characteristics of the valve. This paper demonstrates that the used valve model yields the results, which agree well with the conducted experimental study. Therefore, validation of the numerical model and the modelling results in the form of theoretical valve characteristics was accomplished. Firstly, the paper presents details of a numerical approach employed to evaluate valve performance and then analyzes the simulation results. Next, the valve performance is experimentally validated by testing a prototype valve on a hydraulic test rig capable of measuring the volume flow rate, pressure levels in up- and downstream lines of the valve over the entire spool angular stroke. Initially, average discrepancies between modelling and test results were 52.46% for the metering and 82.78% for the pressure drop function. Correcting the model geometry aimed at eliminating differences between the valve model and the practically used prototype-test rig system enabled reduction of the error between experiment and modelling by 47.75% for the pressure loss function. This confirmed validity of the simulated characteristics of the valve. The benchmark comparison of pressure losses confirmed average 71.66% energy dissipation reduction compared to the industry-available analogue valve.

© 15th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies, CM 2018/MFPT 2018. All rights reserved. High flow rate control is very important for different applications ranging from constructional, industrial, military and aerospace. Generally, hydraulic control relies on different types of valves. For example, poppet and spool valves have been implemented in Independent Metering (IM) system which is usually installed in mobile hydraulic machines such as excavators. Recently, a novel rotary flow control orifice has been developed to design a control valve for high flow rate applications, and a stepper motor was selected as the main actuator for this orifice to grant more accuracy and controllability. The coupling between these two main components requires analysis of the internal dynamical interactions and their effect on the performance. Friction torque is an important parameter to be considered in this design. The paper includes analysis and modelling of the friction torque in the orifice which affects the coupling, also it contains a model validation and evaluation resulted from friction practical measurements.

© 15th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies, CM 2018/MFPT 2018. All rights reserved. This paper aims to create a sensor-less feedback position detection for a flow control orifice actuated by a stepper motor. Nowadays, many applications such as hydraulic and pneumatic systems use a stepper motor as an actuator, instead of traditional mechanical or solenoid. In nonlinear environment such as hydraulic systems, a stepper motor may suffer from step losing and leads to poor controllability of the system. Mechanical sensors are usually used as a feedback of the position and speed, but at the same time the harsh environment of hydraulic applications prevents implementing this kind of sensing. On the other hand, a sensor-less technique based on Kalman filter was used to control a stepper motor in different applications. This research represents a primarily investigation of the performance of Kalman filter in these for the valve based on modelling and simulation.

© 15th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies, CM 2018/MFPT 2018. All rights reserved. Real time-in-service interfacial load measurement and load tracking between prosthetic socket and the residual limb is of paramount importance. Noroozi et al proposed an inverse method approach using ANN to predict the magnitude and location of the interfacial load between prosthetic socket and the residual limb from the structural response of the socket to the normal internal load due to contact between the stump and the socket. Here the socket mechanical properties act as the transfer function between the forces acting normal to the internal surface of the socket forces and the resultant strains generated on the external surface of the socket. Using this method, it is possible to use the external strains to predict the internal load that caused the strain. With this method, there will be no need for the socket or tissue properties or the exact socket thickness. Using this technique, one can simply transform everyone's socket into their own dedicated transducer suitable for measuring, tracking and monitoring the resultant interfacial load on the internal surfaces of the socket for that user. Currently, all socket interfacial load measurement systems require tactile sensors which require the prior knowledge of the location of the contact points. This makes it impossible for the tactile sensor to predict the magnitude and location of high-pressure points. Alternative tools are tactile sensor placed in liners or drilled and mounted through the socket wall, or total surface bearing ones that are subjective and not suitable for everyday use. For that reason, they require the knowledge of the contact point or areas of high load intensities. The proposed new system requires none of the above constraints and due to its unique design, it is immune to the changes in the overall boundary conditions, making it an invaluable clinical sys

The hydraulic independent metering (IM) is an advanced actuator driving technique that allows the implementation of advanced control algorithms or methods. The main concept of IM is to control hydraulic actuators ports, which are the meterin and meter-out, separately. In this paper, a novel stepped rotary type valve has been developed for embedding in hydraulic independent metering systems, instead of conventional types such as poppet and spool. The insertion leads to developing different and novel control techniques, which require a software in loop and hardware in loop simulation of the proposed system. The paper explores the dynamic representation of this valve and defines its own performance limitations. This includes the development of a linear model comprising its two main sub-parts which are the stepper motor and the rotary orifice. Consequently, the linear timeinvariant methods are used to explore the performance of the valve by considering the effect of different parameters namely the pressure drop, friction coefficient, damping coefficient and bristle coefficient.