Performance and Efficiency Testing of Actuators

Founded in 1994, LOGICDATA is based in the small town of Deutschlandsberg in southern Austria. With offices in Austria and USA as well as production locations in the Czech Republic and Hungary, the LOGICDATA team consists of over 300 industry-leading professionals. In 2021 the company merged with the Chinese manufacturer JIECANG to combine forces and enhance mutual growth.

Founded in 1994, LOGICDATA is based in the small town of Deutschlandsberg in southern Austria. With offices in Austria and USA as well as production locations in the Czech Republic and Hungary, the LOGICDATA team consists of over 300 industry-leading professionals. In 2021 the company merged with the Chinese manufacturer JIECANG to combine forces and enhance mutual growth.

Having won several prizes, the company uses a range of intelligent electronics, mechatronics, and embedded software solutions to produce adjustable furniture for homes and offices. 

Actuator Testing

LOGICDATA is testing embedded actuators driving the legs of electrically adjustable office tables. The height-adjustable mechanism, the drivetrain of the telescoping legs, basically consists of a brushless DC motor, a gearbox, and a spindle system with integrated brake operating at speeds of up to 80 mm/s. 

With the increasing demand for customized adaptations, the company strategy “One Vision. One Provider” leads to more modularity (“Premium Modular Solutions”) and a growing product portfolio. To guarantee a stable product life operation, new prototype designs must be analyzed and verified in a short time. LOGIGDATA performs more than 200 tests for an actuator design to pass as OK.

The company has to ensure that the components involved move smoothly and quietly under various load and speed combinations. A distributed model with actuator-integrated strain gauge sensors in each table leg, rather than a single central sensor, ensures greater sensitivity during vertical movement. This Intelligent System Protection (ISP) minimizes system damage and recognizes collisions effectively. 

The Testing Solution

Mr. Andreas Pichler, a Mechanical Expert, showed us around his laboratory with many professionally composed testing setups. “It is imperative to analyze the efficiencies of every single component of the whole power chain,” he says, “for us to know all power losses and thus identify optimization potentials.” For this purpose, LOGICDATA built a specific actuator efficiency test bed.

Engineers clamp the device under test (DUT) into a yellow test stand holder and connect it electrically. The DEWE-43 inside the cabinet measures the 3-phase motor voltages and currents, the distance, force (torque), and velocity, e.g., 38mm/s to high-speed applications up to 80 mm/s. The DewesoftX software then enables real-time efficiency calculation by comparing the mechanical power output to the electric input.

The counter-force is adjusted on a control panel by pneumatic to simulate different loads. Furthermore, the engineers compare the resulting support torque to the applied force, which also gives knowledge about the efficiency of the integrated spindle system. In this way, they evaluate the crucial self-locking behaviour of the actuator, e.g., in the case that somebody is sitting on the desk, it must not move downwards. The setup also allows adaptations for testing different customer requirements.

DEWE-43A data acquisition system

DEWE-43A weighs less than one kilogram and is small enough to fit in a hand. The DAQ instrument is light to be portable but also robust and capable. Every unit is CNC machined out of a solid aluminium block and offers eight high-speed analog and eight super-counter inputs. The instrument also offers an unmatched price/performance ratio.

DEWE-43A is suited for a wide range of dynamic data acquisition applications. The instrument includes advanced data acquisition, recording, and analysis software DewesoftX. Dewesoft developed this DAQ software around one core philosophy - one software for all testing applications. This combination makes DEWE-43A the Swiss Army Knife for testing and measurement.

Standard counters available in most DAQ systems today provide only integer resolution outputs, e.g., 1, 1 or 2, 2. As a result, their outputs are always one sample behind the analog sensor data, a real problem in applications like rotational or torsional vibration when a phase shift of even one piece can change the results.

SuperCounters solves this problem by extracting floating-point values like 1.37, 1.87, and 2.37 and aligning them precisely in time with the rest of your data. A SuperCounter is two counters in one. The input is fed in parallel to both counters, and the sub-counter measures the exact time of the signal’s rising edge, thus calculating and perfectly aligning the real counter value with the analog values.

Dewesoft SuperCounter® technology is compatible with multiple encoders, gear tooth sensors, proximity sensors, etc. DEWE-43A and other Dewesoft systems like SIRIUS, MINITAURs, and KRYPTON are configurable with one or more SuperCounter inputs. 

The DEWE-43A data acquisition system also supports the sensor standard, TEDS (Transducer Electronic Data Sheet). The technology allows the engineers to quickly build the test setup onsite and perform different kinds of tests, such as:

• motor performance tests, 

• lifetime performance tests, and

• acceleration/deceleration profile test.

Visualization and Reporting

The customized DewesoftX software splits the measurement screen into two halves. On the left side is a schematic of the whole actuator, with motor and gearbox on top and spindle system with telescopic mechanism on bottom. Different colours visualize the measured values: electrical and mechanical power, force, torque, efficiency, distance, and driving speed. The unit, e.g., mm/s, makes an additional channel description dispensable, which results in a simplified, cleaned-up setup.

The right side of the screen shows the header information, e.g., the test performed, on which design revision, with which test criteria, and who was in charge of the test. The test parameters can be modified by control channels and shown in a small sketch shows. The software saves the data to the data file for later reproducibility.

The Dewesoft setup already shows the real-time results during testing, displayed in a table for immediate evaluation. The software updates the report continuously. It is ready when the engineers conclude the test - a feature that saves much time.

Actuator Lifetime Simulation

Before any product release, LOGICDATA also needs to know how the actuator performance may change over its lifetime. Therefore, the company includes several different performance measurements in an actuator life test. 

Equipment used:

• DEWE-43A: Data acquisition system

• DewesoftX: Data acquisition software

• DSI-V-200: DSI adapter for ±200 V analog input

• LEM LTSR 15-NP Current Sensor

• KR110a 2000 N ring-torsional force sensor

• ME TD110a 20 Nm torque sensor

• KM26z 500 N push-pull load cell

• K+C precision glass scale M5 linear distance sensor (2x)

• SICK-DBS60E angle encoder

While the actuator is loaded with a defined load over the lifetime, the equipment is connected and the DC voltage current going into the actuator is measured. The engineers tap into the communication between the control box and actuator and contract a voltage peak every time the motor rotates.

The counter set up in the DewesoftX data acquisition software ensures fast motor speed calculation. 

The test engineers know the load the actuator needs to move and mount a force sensor under it. They can then calculate the outgoing mechanical energy of the actuator. This information allows the calculation of the actuator efficiency. At the end of the life test, the engineers compare results from the same actuator over its lifetime and note any changes.

Conclusion

The efficiency test bed is just one of multiple test beds operated by LOGICDATA. Other tests cover spindle testing, endurance testing for the product release, and testing in an acoustic chamber. Furthermore, in separate End-of-line test beds, every actuator instantly gets a final check after production.

The DEWE-43 system portability and flexibility are essential features for the LOGICDATA measurements. Seamless integration of data acquisition hardware and software brings unparalleled ease of use.

The DewesoftX DAQ software calculates its advanced mathematical formulas in real-time. A feature that gives the engineers a live view of the results and enables them to adjust measured parameters during the test. 

“Our development of the new and mechanically more complex spindle system would have been impossible without the test bed,” Mr. Andreas Pichler says. “We created the next generation of inline drive actuators, which allow high flexibility of speed and load combinations. Our DMDinline and DCDinline drives will fulfil various customer expectations and set a new standard in the industry. We continuously optimized the Dewesoft setup for fast evaluation in this extensive product development. With faster progress, it's also more fun to work!”

At the time being, LOGICDATA is working with the C++ Script option inside the Dewesoft Mathmodule to simplify their testing setup even more and bring in further functionality. The simplification increases the testing efficiency and delivers the desired results with the first measurement, saving a lot of time and money at the end of the day. 

“My conclusion for Dewesoft is: You can get measurement data quickly, but when more detailed analysis is required, it makes sense to dive deeper into it.