Traditional valve to control the entry and exit of oil through the mouth for a spool, I listen to the two oil as early as the relationship between open spool design and processing have been identified when, in the use of the process can not be modified, so that through the mouth of the two oil flow or pressure can not be independently controlled.
With the micro-processing controller, a decline in the cost of the sensor components, control technology, continuous improvement, making dual-spool control technology in the field of the application of engineering machinery. Utronics British companies make use of its patented technology and developed a dual-edge multi-spool valve, has been widely used in JCB, Deere, DAWOO, CASE, such as the company's excavator, * vehicle, loader and backhoe loader and other products . In order to meet the China Construction Machinery products on the functional requirements of the hydraulic system. The degree of automation and control stability, and continuous improvement, Utronics timely products to enter the Chinese market, has been initially completed the building work (5t) loaders, Zhanyang (8t) excavator prototype debug and entered the testing stage.
1, the traditional single-spool valve defects
The traditional single-spool hydraulic valve system which consists of the following reasonable solution can hardly function and control of conflicts between:
(1) the design of hydraulic systems to enhance system stability and reduce the load on the pace of change, or the expense of some of the features we want to achieve, or an additional hydraulic components, such as speed control valve, pressure control valves, etc., through increase damping and improve system speed to increase the stiffness of stability of the system. However, the increase in this component will reduce efficiency and waste of energy; will make the whole system can be reduced * to increase the cost.
(2) As for the specificity of the structure, enabling users to achieve a particular function in the need to purchase the hydraulic components, together with construction machinery manufacturers in accordance with the requirements of different end-users to design the corresponding feature, which will result in manufacturers procurement of similar, multi-standard hydraulic control components to meet the needs of different functional requirements, is not conducive to general-purpose products and product management, at the same time will greatly improve the product cost.
(3) The executive body of hydraulic oil into and out of control through a spool, a separate executive body on both sides of the pressure control is impossible. Therefore, the role of oil pressure executive body movement in the opposite direction, with the oil hypertension, the executing agency for the shelf-life movement, we must raise the pressure into the oil side. This will allow the function of the hydraulic system to increase consumption, low efficiency, increased heat.
Dual-spool hydraulic system technology, as the implementing agency access to the oil-side spool valve port location and control their own independence, so that the two spool through different combinations of control, the use of software programming can be very good traditional single-valve system will not solve the problem, but also can easily achieve the traditional hydraulic system functions difficult to achieve.
2, two-spool valve of the two basic control strategies
As the dual-spool to two oil-for population control flexibility, the two I can take the oil flow control, pressure control or pressure control flow. Introduce two simple positive control strategy.
(1) the direction of the load throughout the course of their work remain the same
We know that the truck crane, excavators, loaders, etc., its hydraulic cylinder in the direction of the course of their work load is always maintained. Luffing crane in the following as an example to explore the hydraulic cylinder of the dual-spool control strategy.
Luffing crane tank in the course of its work force, load direction remains unchanged, so we can take control of hydraulic cylinder rod pressure control, with no flow control cavity under the control strategy.
Rodless cavity by detecting the flow control is connected to the non-stroke side valve cavity on both sides of the pressure before and after, and then in accordance with the inflow or outflow of the required number of flow to calculate the size of the spool open; rod side of the use of pressure control chamber so that the side to maintain a low pressure, making more energy-saving and efficient.
As we shot chamber in the absence of a flow control, so the original control system of the balance valve used in a hydraulic control can be used to replace a one-way valve. This will remove the balance valve instability brought about by the system, thereby enhancing the system stability.
(2) In the course of the load in the direction of change
Under such circumstances, to take "into the oil-side pressure control, oil-side flow control", in the hydraulic cylinder rod side with cavity pressure control, no side bar cavity flow control.
The same direction as the load, due to adopt the oil side of the flow control, we can balance valve with two-way hydraulic control valve to replace a one-way, thereby enhancing the stability of the system. Into the oil-side pressure controller to maintain a lower reference pressure, on the one hand, improve system efficiency, on the other hand, the system is no cavitation.
In order to change the direction of the work load can be a very good body control, a PI controller will be applied to the pressure chamber rod controller, when the load changes direction, no bar will reduce the pressure chamber; if the will rod cavity to maintain a very low pressure, when a large load, the hydraulic cylinder in the opposite direction to the movement. At this point we are able to use the increased surveillance of the PI controller Rodless changes in cavity pressure, when the PI controller detected Rodless set cavity pressure below the reference value, will increase the cavity pressure controller rod set pressure, thus ensuring the normal operation of the system.
3, Ultronics hydraulic control system
Ultronics is a design, research and manufacture of electronic hydraulic technology companies. The hydraulic control system uses the CAN bus communication, dual-spool control technology, through a combination of the two spool control, can achieve a wide range of control to the executing agencies in order to enhance system stability, reduce energy loss, while makes the system more simple, lower costs, speed up product development speed, these are the traditional electronic system can not do.
Ultronics control system in general by the manipulation of the handle hardware, electronic control unit ECU, control valve, dual-spool hydraulic valves and external components such as sensors or switches, which through the CAN bus communication, hydraulic valves and electronic control system for the meeting point of the hydraulic system, the system is another important component of the software.
Photoelectric controller for non-contact form with up to 4 ratio the proportion of output or two outputs and a maximum of five switches. Proportional switches and options for self-locking. Reached their level of protection IP67. Handle the delay characteristics of the output, such as curves and dead-zone can be modified JoyVal special software.
ECU Electronic Control Unit for the 12V and 24V voltage has two, 25 Road and 50 Road, the two interfaces, providing analog and digital input and output interfaces, while the electronic control unit also provided a letter CAN interface, the system can receive sensor or control signals or connect with other systems. ECU has stored all the necessary system control applications, the application can be derived from or connected to the ECU handle other devices and signals (such as sensor detection signal, the engine control system for information, etc.), After treatment, all converted into spool command action.
Ultronics control system lies in its unique dual-spool control technology, there are two each spool valve, which is equivalent to a four-way valve into two three three three-way valve combination, the two valve core is alone control, control logic can also be carried out in accordance with paired control, and I have two oil pressure sensors, each spool has a position sensor, by sensing signals in closed-loop control of two separate hydraulic oil pressure or flow control, high control precision, through different combinations of control can be many solutions to meet the needs of the system.
Each valve has two complete set of good mixed-signal ASIC (application specific integrated circuit analog) and a RISC (reduced instruction processor). Sensor controller to provide these incentives and compensation, to control power transmission to provide spool control and CAN bus communication software. Spool motion control strategy and specific parameters can be charged with the implementation of the user component in accordance with the requirements set or modify. Control valve orders received after the embedded processor on the operation of spool motion control software function set, a number of functional coordination between the valves is done by the ECU in order to achieve the complexity of the system. Classification means that the control system has very good flexibility and easy to build complex control systems.
Ultronics control system functions through the application of software diversity is achieved through the establishment of targeted control software. Ultronics control system can achieve a very wide range of functions. Crawler excavators, wheeled excavators, loaders and other advanced models in the operation of comfort, operating efficiency, operating cost of consumption, fault diagnosis, environmental protection efforts, such as engine and hydraulic system of the state of the adaptive control, specific features and so on, can be used to achieve Ultronics system.
In short, through the CAN bus communication, the unique structure of dual-spool and pressure sensor applications, as well as pressure or flow of the closed-loop control technology, Ultronics the company's electronic control system for hydraulic control system so that construction machinery in the functional diversity, the achievement of flexibility, lower cost, and control concept, and many other aspects of the maintenance mode will trigger a revolutionary change.
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