testControl enables drive and positioningwithout effort.

Zwick guarantees highest positioning accuracy andprecise speed control , and thus very rapid reaching ofcontrol targets with the adaptive controller implemented on testControl . Even for specimen with a non-linear relationship of force and deformation, the highest possible reproducibilityof your test controller adapts itself in real time to this behaviour and guarantees tests to test standards. Whereby the controller adaption takes place entirely automatically, i.e. no preselections must be made by the user, nor owing to cost and time intensive pre-tests.This automatic and user independent controller adaptionpresents you with the . Furthermore, these properties of the adaptivecontroller reduce the time requirements for a test even more.
Fig. 13: Black curve with Pid controller, blue curve driven with adaptive controller

testControl for more advantages for the user

testControl is a powerful measurement and controlelectronics with modular setup. It is an electronic platform that has been developed by Zwick especially for static test machines.Long term permits customised configuration for each testsituation.A well thought out security for investment and for the future modularitysetup to the requirements of a materials industrial testing machine is guaranteed by the use of most modern technologies and highest quality guidelines in development. A compatibility concept enablesexpansion of an existing electronics by further components at any time: a further guarantee for investment and future security.Zwick sets new standards with a very wide ranging standalone version with which you can carry out your tests even without a PC. PC Operation is made with the testXpert
Fig. 12: Left curve: Non-linear relation of force-travel Right curve: Constantforce increase rate ® software which has proven itself for many years now. Thus the complex testing of foam materials, componentsand specimen with non-linear force-travel behaviour becomes extremely simple, or it thus becomes possible. The right hand curve in fig. 12 shows how the adaptivecontroller automatically adapts to changing ratios (left hand curve in fig. 12). This specimen becomes increasingly harder as the test progresses, i.e. it doesn’t behave like a spring that shows the same hardness (spring constant) over the entire loading range. Thus the controller must constantly adapt its controller amplification, this can only be set to an optimum by the user for one range when using a static PID controller. Fig. 13 shows the direct comparison between a PID and an adaptive controller for the same specimen. Thereby the black curve shows optimum controller settings only for the middle range. The preselected targets are not reached precisely in the beginning range, the machine oscillates in the end range as the controller here has been set too “exact”. The blue curve that was recorded with the adaptive controller shows optimum target positioning over the entire range. 11