Chances and challenges
Motion controls for hydraulic actuators close the control loop in a decentralized way and release the superior control. Functions which were previously purely hydromechanical or hydraulic, are now moved into the software: Predefi ned functions take over the control of position, velocity, distance/force, diff erent synchronous cylinders or path-dependent braking. If the functions of the fl uid technology are saved in the software, the motion controls can automatically compensate them internally. For the superior control system, hydraulic drives will act just like electromechanical ones. By bringing the functions into the software, parameter changes are possible in real time during the process at any time. The user changes the parameters and sends them via a network connection to motion control. In the next cycle, the new parameters are implemented. This way, they support the trend to produce small batches and in the best case, they reduce the retooling work for new products to a few mouse clicks.
Expanded sensor technology for new dimensions of the diagnostic capability and availability
Apart from the intelligence for controlling movements, the intelligent, interconnected hydraulics includes a significantly expanded, partially “virtual” sensor technology. Modern hydraulic power unit are equipped with an own intelligence with integrated sensor packages. The sensors permanently record the operating conditions. Manufacturers of hydraulic components are busy modeling and evaluating realistic life cycle models for all components. For example, they know how many switching cycles a valve resists. A corresponding software counts the switching cycles in an application and deducts them from the expected life cycle. For the total evaluation of a system, models for all components are required, and the behavior in the specific application must be simulated. This way, statements concerning the failure probability can be made during operation online. This condition monitoring is the requirement for predictive maintenance concepts. If the measured values exceed or undercut defined tolerances, corresponding messages are sent to the control system or via SMS or email to defined persons.
The combination of sensor technology with life cycle models and mathematical models of cause-effect relationships has the potential to improve the prediction accuracy significantly. However, this requires expert knowledge over the component, systems and fluids to be monitored. Especially in plants for permanent processes, it is an important lever to increase the availability and to prevent the extremely expensive production stops. The first manufacturers for hydraulics are already equipping this type of plants with extensive sensor technology and analyze the data on the users’ request. The trend goes from the offline analysis of the collected data towards a near real time online analysis with selflearning software. This way, the knowledge about the cause-effect relationships is extended with each data set and thus the possibilities to increase the availability with predictive maintenance. Users will be able to decide for themselves where the data will be saved, if they want to carry out the maintenance themselves or if they outsource this service completely. Even existing hydraulic systems can be retrofitted with sensor technology and interconnected and thus provide these advantages. Especially in the field of services concerning maintenance, new, disruptive business models will be possible.
Simple, networkable hydraulics can be integrated seamlessly into Industry 4.0 concepts by machine and system manufacturers. Above all, it offers multiple possibilities to save costs and increase the performance. With intelligent, networkable hydraulics, OEMs save time and costs in the entire engineering process by simulating systems, with a quick interconnection, and flexible configuration.
For design and configuration, developers of the OEMs use the virtual images of the motion controls of their hydraulic actuators. They are integrating them into simulation tools which consider the special features of fluid technology. The software enables further the simulation of the control functions. This way, machine and system manufacturer can validate their concepts on the computer and detect over- or undersizing without having to built a complex prototype. Additionally, the efforts for installation and commissioning are reduced signifi cantly. In the end, this reduces the time to market and significantly reduces the total engineering costs.
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