Complex Methodology, Simple Process

Less frequent moving between office and test bench: “Online DoE” saves time and money – while delivering very good results

It hardly gets more convenient than this: with Online DoE, IAV makes it easier for calibration engineers to use the tried and proven Design of Experiments (DoE) method. Almost all work steps take place at the test bench. Using already taken measurements, the IAV EasyDoE product – soon in a new release under the name of IAV Kasai – automatically computes the next test point. Even the parameter adjustment ranges are determined directly during the process. The new approach saves time and produces very good results.

The basic idea behind DoE: instead of using many measurements to scan the entire parameter space as finely as possible, calibration engineers restrict themselves to a selection of relatively few measurement points and use them to compute the values with different settings. This saves time and cuts cost. Numerous clients have been benefiting from this highly efficient method for years. Applying the IAV EasyDoE product, even users with only little relevant experience can achieve excellent results without any major effort.

In future, work will be even easier: Online DoE means the end of other time-consuming work processes as the product takes care of them itself. “It used to be necessary for calibration engineers to move back and forth all the time between their desk and the test bench”, says Dr. Carsten Haukap, Project Manager at IAV. “At the test bench, they first had to determine the engine’s physical limits, followed by designing the experiment at the desk. After this, more measurements were conducted at the test bench, whereupon the modeling had to be done in the office. The model was then validated again on the test bench, with subsequent optimization finally taking place at the desk.”

Almost all process steps are performed at the test bench

With Online DoE, most work steps can now be done at the test bench. One work step is even no longer necessary at all. Determining the physical limits is now part of the DoE process which alone saves a lot of time. Test points are defined in an iterative process: “Proceeding from an initial sequence, the new algorithm consecutively determines the various test points itself”, explains Nino Sandmeier, development engineer at IAV. “This means that each event measured also immediately is used for planning the next experiment as well as for training and validating the models. This too produces better results in a shorter time.”

As with the conventional DoE method, this results in a mathematical model, such as for calibrating a compliant exhaust gas aftertreatment system, while at the same time minimizing fuel consumption. In contrast to the conventional method, however, the calibration engineer no longer needs to keep moving back and forth between office and test bench. Only the last work step – model-based optimization – still takes place at the desk. “Online DoE performs many of the activities users once had to do, plus the fact they now need hardly any prior knowledge”, Haukap says. “In the meantime, most of the work is done automatically, if preferred over night at the test bench.”

Closely connected to A&D Orion

Online DoE is integrated as a new option in the time-tested IAV EasyDoE product and is easy to activate at a simple mouse click. The development tool is closely connected with A&D Orion software for automating test benches. In an initial step, the experiment sequence and parameters are entered into A&D Orion and transferred to IAV EasyDoE. At the test bench, both products then permanently exchange data: IAV EasyDoE delivers the next experimental point which A&D Orion then applies and measures. Alongside this, IAV EasyDoE computes the models and optimizes the test design. With its simple external interface IAV EasyDoE can also work with other automation system solutions.

Online DoE is based on new mathematical methods developed and implemented by IAV. “Behind this is a complex methodology which is presented to the user as a straightforward process”, Sandmeier says. “We are confident that acceptance of the DoE method among calibration engineers will continue to rise.” There are sufficient arguments in its favor: IAV’s experts have been able to confirm in numerous projects that the approach delivers very good results while also saving time and cutting costs. This makes them certain: Online DoE will be tomorrow’s preferred method.