Can electric tools be developed and made to more closely fit the way they are actually used by humans? Researchers at the new Power Tool Test Centre of Karlsruhe Institute of Technology (KIT) are now finding out.
Drilling, cutting, grinding and milling tools are indispensable everyday tools, but there is the need to ensure they are developed and tested under real-life conditions.
According to Professor Sven Matthiesen, head of the Institute of Product Engineering at KIT, when developing tools, it is important to understand the overall man-machine system.
“With the Power Tool Test Centre, we are now able to study the mechanical interactions between user and tool in detail and simulate them in a reproducible way. This is the key to product innovation,” he explained.
During the development phase of power tools, manufacturers undertake comprehensive hand-held testing. Because the tools must be tested by many different persons, the results can be highly varied.
The Test Centre will enable automated testing of electric power tools without the uncertainties involved with hand-held tests by humans. User behaviour is analysed and integrated into automated tests in the form of reproducible and configurable parameters. The robots then guide the tools in the same way that humans would do, but with reproducible movements.
The Power Tool Test Centre contained three test benches.
The first is the User Interaction Test Bench, which investigates the mechano-dynamic properties of a suer working with power tools. A computer transmits measured or simulated movements to a sensing handle at the test bench. The forces and torques between the user’s hand and the handle are captured. The systems are able to simulate even high accelerations, such as jolting vibrations common when using hammer drills or impact wrenches. The sensing handle can be positioned freely to test working overhead or on the ground.
The second is the Automated Power Tool Test Bench where the measured user influence can be mapped in a reproducible way. Here, the arm of an industrial robot guides the electric tool by following exactly the captured force profiles of a user.
Finally, the Power Tool Interaction Test Bench examines the operation of the tools when used on diverse working surfaces in various spatial orientation. Different surface types, such as concrete, wood, or metal can be positioned in any orientation by means of an automated, flexible surface positioning system.
This makes it possible to conduct hand-held tests as well as automated tool tests in any spatial orientation and to identify and measure the interactions.
The researchers noted that modern power tool development is influenced by the complex interaction of mechanical, electric, and computing components. This means that there is the need to test individual components in a realistic environment early in the product design process, even if prototypes of the overall system are not available yet.
The Power Tool Test Centre includes the IPEK-X in-the-loop approach, where simulation-based coupling is used to validate components such as a power tool or an electric tool.
Individual user behaviour is reproduced by high dynamic actuators using specific models and simulations. This approach, which can be based on simulation and actuators, allows the R&D team to vary system parameters very flexibly and efficiently analyse the effects or to exchange data and parameters that were acquired at test benches at different geographic locations and at different points in time.
[In the KIT Power Tool Test Centre, robots perform automated tests on electric tools just as humans would do. Photo: KIT]