Research projects

Development of (optical) sensors

The core of research is developing a small scale torque sensor with contactless measuring system.

The basic principle is upon the birefringence effect of optically active materials. Here a Perspex tube of thin wall thickness is used. When torque is applied, stress arising in the tube changes relative retardation, causing the change in light intensity, which could be measured optically. The main goal of this study is to create a torque sensor of industrial application.

Effect of threaded connection tolerances to pre-stressed bolts

Combination of extreme values of components within the tolerance zone or the presence of detergent and oil can lead to insufficient pre-stressing force.  The risk of co-occurrence of these effects is 0.015%. The main goal of this research is to establish a general relationship, which takes these factors into account.  The subfields of the research are:  stress–strength analysis of screws; geometrical size determination of nut and bolt pairs; establishing relationship between tightening torque and screw force taking lubrication conditions, profile errors and geometrical sizes into account; finite element analysis to determine the occurring stress and deformation of the joint.

A Possible Method for Developing Spatial Awareness in Teaching Technical Drawing.

In previous research the age of 14-16 has already been  proved to be the period when  spatial awareness can most effectively be developed. In the first place, our method is aimed at this age group but we truly believe that good results can be attained in tertiary education as well, moreover, studying the material is definitely fruitful for those laymen who ”just” want to polish their technical skills.

Act and wait control concept

Position control of a block using a digital a PD controller is investigated. It is known that feedback delay in the control loop strongly affects stability properties. One possible technique to overcome the destabilization effect of the feedback delay is the act-and-wait control concept; the control force is switched off and on periodically in time. If the switch-off period is larger than the feedback delay, then the system can be described by a discrete map of dimension equal to the dimension of the open loop system. Two criteria, which are often set to control problems, are investigated: the overshoot and the settling time. It is shown that there is no overshoot if the critical (largest in modulus) characteristic multiplier is a positive real number, while the settling time is related to the magnitude of the critical characteristic multiplier. Stability diagrams representing this information are presented and the behaviour of the system at different control parameters is demonstrated by numerical simulations. It is shown that the act-and-wait concept results in a better performance with respect to both criteria, while it allows the application of significantly larger proportional control gains, which is a useful feature to avoid position error against friction.