Standardization helps to align complex products with customers’ systems in the most cost-effective way and make innovative technology widely available. This is something that Thomas is currently demonstrating with its digital electrohydraulic actuator (EHA), which can be found in various types of forestry machinery and self-driving port cranes, among other places. Originally developed for a specific application, the compact and self-regulating hydraulic controller is now the first Thomas product that can be adapted quickly and inexpensively to any system used by component manufacturers or OEMs thanks to the company’s new in-house software and hardware standard TES (Thomas Electronic Standard) and Thomas Software Control (TSC). It is hoped that this example will soon set a precedent, with comparable products set to be available faster for all manner of customer systems in the future.
How an EHA works
The actuator is made up of two Thomas proportional pressure-reducing valves fitted inside an aluminum die-cast housing together with a control board and an integrated displacement sensor. Several of these actuators can be installed directly inside the customer’s system at a later stage and connected electrically to the cable harness. The vehicle’s controller communicates with the units via a CAN bus signal. When the operator moves the joystick, the actuator controls the customer’s system via the two valves. The displacement sensor serves as an additional safety device here, closing the actuator’s control loop via the position signal.
Thomas Electronic Standard (TES)
The Thomas Electronic Standard (TES) is a modular system with standardized interfaces, on the basis of which next-generation products can be developed safely, flexibly, and cost-effectively in line with Thomas’s “Sense. Think. Act.” strategy. Development times can be reduced significantly. Verification also requires less time and effort, because many components can be reused from existing projects. On the hardware side, a portfolio of tried-and-tested circuit blocks and components enable functions to be illustrated quickly and synergy effects leveraged in procurement. Development is done using models on abstraction levels in order to gain a better picture of the complex system. “The TES ensures traceability of the source code and requirements,” says System Lead Engineer Gregor Hombach. “This improves and speeds up development activities: If a requirement changes, for instance, its trace links will indicate what other connections, or ‘artefacts,’ are related to it. This allows them to be checked easily and adjusted if required.”
Thomas Software Control (TSC)
In the past, the development team in the Business Unit Off Highway Solutions faced the challenge posed by every customer using different software. With Thomas Software Control (TSC), Thomas now had to design a configuration platform that enabled it to adapt the EHA precisely in line with the customer’s needs. TSC is a standardization solution in the form of a PC application with a CAN bus interface for configuring, controlling, and updating Thomas’s “Sense. Think. Act.” products. The CAN bus links up electronic assemblies such as controllers, meaning that data is exchanged between individual controllers on a standard platform. Combined with an attractive UX design and a command-line interface (CLI), TSC delivers numerous benefits in a whole range of application scenarios (see info box).
Customers can commission Thomas products easily in their own
TSC provides support with configuration, actuation, and troubleshooting
standardized interface for developing test scenarios easily
standardized interface for configuring STA products and running software updates during production
Looking ahead: developing the EHA TES further into the pioneering EHA 3.0
Based on the Thomas TES and TSC, a next-generation EHA has been created that can be customized to suit customers’ current requirements: the EHA TES. More updates in the form of the future EHA 3.0 are in the pipeline, including integrating a plug-in connector, optimizing the sensor system, and fixing the circuit board in place using proven assembly and connection technology methods instead of the die-cast solution. With the requirements of the various groups of customers all round the world varying considerably, three configuration levels are planned: Basic, Extended, and Advanced. The modular design allows standard criteria (flow rates, voltage, plug-in connector, sensor, and adaptor) to be modified flexibly.
The EHA TES is an advanced product that delivers attractive added value. The greater degree of software modularity means that changes to the software can be implemented faster and, most importantly, in a way that fits each individual customer. By pursuing this new development path, Thomas is showing itself to be a leading innovator in smart hydraulic pilot controllers. Our current project, EHA 3.0, is thus the next step.