Haptics Test Stand
Initial situation and project task
Customers evaluate a material’s quality using all their senses. Most products are thoroughly tested for their haptic properties before a purchase decision is made. Customers do not only evaluate mechanical properties but also subjective properties such as surface, texture and shore hardness.
Although a great number of textures is currently available and plastics can be modified by various additives, it lacks a basic knowledge of how materials are evaluated haptic. Therefore, Fraunhofer UMSICHT analyzes various plastics with different surfaces and textures regarding their effects on evaluation by human beings.
The haptics test stand, which has been developed as a cooperation of Fraunhofer UMSICHT and NOFFZ, is expected to realize a concatenation of objective measurement data and subjective perception.
Centre of any testing cycle is the testing person, who analyzes a material sample, which is fixed to the tester. As the test person is evaluating the material, various physical measurement data is recorded and the person’s impressions are registered, as well. A subsequent data analysis allows for correlation of objective measurement data and subjective personal impressions.
A simple and intuitive user interface is expected to guide test supervisors and test persons reliably through testing profiles. Such a profile is expected to be based on two ways of analysis:
Implementation and challenge
The greatest challenge we faced, was the implementation of the recording system for the measurement data and of the test control. We had to implement a measurement system for 3-dimensional forces, a tracking system for the finger’s movement and temperature analysis for the materials.
Customers evaluate a material’s quality using all their senses. Most products are thoroughly tested for their haptic properties before a purchase decision is made. Customers do not only evaluate mechanical properties but also subjective properties such as surface, texture and shore hardness.
Although a great number of textures is currently available and plastics can be modified by various additives, it lacks a basic knowledge of how materials are evaluated haptic. Therefore, Fraunhofer UMSICHT analyzes various plastics with different surfaces and textures regarding their effects on evaluation by human beings.
The haptics test stand, which has been developed as a cooperation of Fraunhofer UMSICHT and NOFFZ, is expected to realize a concatenation of objective measurement data and subjective perception.
Centre of any testing cycle is the testing person, who analyzes a material sample, which is fixed to the tester. As the test person is evaluating the material, various physical measurement data is recorded and the person’s impressions are registered, as well. A subsequent data analysis allows for correlation of objective measurement data and subjective personal impressions.
A simple and intuitive user interface is expected to guide test supervisors and test persons reliably through testing profiles. Such a profile is expected to be based on two ways of analysis:
- 1. Several material samples can be fixed to a board for force measurement. When a finger is moved all over the material, all forces are measured and recorded.
- 2. A sample body with an iron core is put onto an electromagnet. By voltage regulation a selected weight has its effect on the body, which is then lifted by the test person
Implementation and challenge
The greatest challenge we faced, was the implementation of the recording system for the measurement data and of the test control. We had to implement a measurement system for 3-dimensional forces, a tracking system for the finger’s movement and temperature analysis for the materials.
All measurement data had to be recorded with reference to the device under test and the specific test person. In this context, parallel recording of all relevant measurement data has been another great challenge.
While the test person moves his finger all over the sample material, the thermal image is recorded by an infrared camera, so that human evaluations and skin temperature can be correlated.
All emerging forces are recorded as well. Therefore, it can be analyzed, how far pressure can influence human impressions of a material. Combined with the physical measurement data it is possible to generate a comprehensive analysis of haptic interaction.
For implementation of an intuitive GUI and for recording of measurement data, NI LabVIEW has been used. For a versatile analysis, all data is transferred to NI Diadem after recording. This tool offers a chance to analyse all data flexibly and to make various calculations with them.
Conclusion and future prospects
Fraunhofer UMSICHT conducts application-oriented haptics research. In this context, the haptics test stand based an NOFFZ’s Universal Tester Platform (UTP) ideally supports physical measurement, data acquisition and analysis.
The system records physical quantities such as pressure, temperature and speed of motion and combines them with the subjective impression of the test person, so that it is possible to judge a material’s quality because of its haptics.
For evaluating a material’s properties even better, it is possible to upgrade the system by implementing additional measurement systems such as an acoustic measurement device.
While the test person moves his finger all over the sample material, the thermal image is recorded by an infrared camera, so that human evaluations and skin temperature can be correlated.
All emerging forces are recorded as well. Therefore, it can be analyzed, how far pressure can influence human impressions of a material. Combined with the physical measurement data it is possible to generate a comprehensive analysis of haptic interaction.
For implementation of an intuitive GUI and for recording of measurement data, NI LabVIEW has been used. For a versatile analysis, all data is transferred to NI Diadem after recording. This tool offers a chance to analyse all data flexibly and to make various calculations with them.
Conclusion and future prospects
Fraunhofer UMSICHT conducts application-oriented haptics research. In this context, the haptics test stand based an NOFFZ’s Universal Tester Platform (UTP) ideally supports physical measurement, data acquisition and analysis.
The system records physical quantities such as pressure, temperature and speed of motion and combines them with the subjective impression of the test person, so that it is possible to judge a material’s quality because of its haptics.
For evaluating a material’s properties even better, it is possible to upgrade the system by implementing additional measurement systems such as an acoustic measurement device.