Adam K Kiss

Budapest University of Technology and Economics · Department of Applied Mechanics

In milling processes, the desired machined surface cannot be perfectly achieved even in case of chatter-free machining due to the thermally induced errors, the trajectory following errors and the most significant one: the cutting force induced vibration errors. In case of vibration, the error is represented by the so-called Surface Location Error (...

In milling processes, the intermittent cutting force may lead to harmful vibrations. These vibrations are classified into two groups. One of them is the self excited vibration which comes from the loss of stability due to the regeneration effect and these vibrations lead to unacceptable chatter marks. The other one is the forced vibration which can...

The aim of this study is to create mechanical model which is suitable to investigate the surface quality in milling processes, based on the Cumulative Surface Location Error (CSLE). This describes the series of the consecutive Surface Location Errors (SLE) in roughing operations. In the established model, the investigated CSLE depends on the previo...

The aim of this study is to create a mechanical model which is suitable to investigate the surface quality in turning processes, based on the Cumulative Surface Location Error (CSLE), which describes the series of the consecutive Surface Location Errors (SLE) in roughing operations. In the established model, the investigated CSLE depends on the cur...

Abstarct This work presents a theoretical framework for the safety‐critical control of time delay systems. The theory of control barrier functions, that provides formal safety guarantees for delay‐free systems, is extended to systems with state delay. The notion of control barrier functionals is introduced, to attain formal safety guarantees by enf...

The goal of this paper is to provide insight about the effect of acceleration saturation in the car-following model. In this contribution, we consider a heterogeneous, mixed-traffic scenario which contains both human-driven and autonomous vehicles subjected to time delays. Corresponding stability charts are provided from which one can tune the cont...

In this contribution, we examine the evolution of surface errors during consecutive milling operations. Its description is based on a nonlinear implicit map, which is suitable to investigate the surface quality. It describes the series of consecutive Surface Location Errors (SLE) in roughing operations. As one of the principal results of the paper,...

This work presents a theoretical framework for the safety-critical control of time delay systems. The theory of control barrier functions, that provides formal safety guarantees for delay-free systems, is extended to systems with state delay. The notion of control barrier functionals is introduced to attain formal safety guarantees, by enforcing th...

Safe longitudinal control is discussed for a connected automated truck traveling behind a preceding connected vehicle. A controller is proposed based on control barrier function theory and predictor feedback for provably safe, collision-free behavior by taking into account the significant response time of the truck as input delay and the uncertaint...

Safe longitudinal control is discussed for a connected automated truck traveling behind a preceding connected vehicle. A controller is proposed based on control barrier function theory and predictor feedback for provably safe, collision-free behavior by taking into account the significant response time of the truck as input delay and the uncertaint...

In this work we present a quantitative measurement-based method to describe the stability behaviour of a periodic dynamical system. In-process response for impulse during milling is analysed to provide operational stability prediction. The proposed method combines chatter detection techniques with the theory of time-periodic delay differential equa...

Endowing nonlinear systems with safe behavior is increasingly important in modern control. This task is particularly challenging for real-life control systems that must operate safely in dynamically changing environments. This paper develops a framework for safety-critical control in dynamic environments, by establishing the notion of environmental...

Endowing nonlinear systems with safe behavior is increasingly important in modern control. This task is particularly challenging for real-life control systems that must operate safely in dynamically changing environments. This paper develops a framework for safety-critical control in dynamic environments, by establishing the notion of environmental...

This study presents an experimental method for detecting and avoiding chatter vibrations that occur during general milling processes. The main idea is to capture the so-called dominant spectral properties from the transient vibrations of the milling process, which gives a good approximation for its dynamical behavior and provides a quantitative mea...

In this paper, we consider the safety of continuous time control systems with input delays. Safety functionals are constructed that define safety sets in the infinite-dimensional state space. Time-discretization is used in order to compute safety sets in finite dimensions and it is shown that these sets approach an infinite-dimensional safety set a...

During the milling of thin-walled workpieces, the natural frequencies might change radically due to the material removal. To avoid resonant spindle speeds and chatter vibration, a precise knowledge of the instantaneous modal parameters is necessary. Many different numerical methods exist to predict the changes; however, small unmodelled effects can...

This paper is concerned with a punch-test based experimental validation method and the investigation of thickness variation in forming process of a thermoplastic material. One of the key factors that characterize the final geometry of thermoformed parts is thickness variation. The material characterization process is usually based on uniaxial measu...

In this study, surface error calculations and stability conditions are presented for milling operations in case of slender parts. The dynamic behavior of the flexible beam-type workpiece is modeled by means of Finite Element Method (FEM), while the varying dynamical properties related to the feed motion as well as the material removal process are i...

Orthogonal planing experiments are conducted with high-speed camera recordings and simultaneous cutting force measurements in order to analyze chip formation during machine tool vibrations. By means of carefully designed periodic forcing of the cutting tool, non-stationary cutting experiments are performed including wave generation, wave removal an...

In this contribution, heterogeneous connected vehicle systems, that include human-driven as well as connected automated vehicles, are investigated. The reaction time delay of human drivers as well as the communication and actuation delays of connected automated vehicles is incorporated in the model. Saturations due to the speed limit and limited ac...

Chatter detection is usually based on the analysis of measured signals captured during cutting processes. These techniques, however, often give ambiguous results close to the stability boundaries, which is a major limitation in industrial applications. In this paper, an experimental chatter detection method is proposed based on the system's respons...

In this contribution, a chatter detection method is investigated for milling operations. The proposed approach can give not only qualitative condition (stable or unstable), but a quantitative measure of stability. For this purpose, it requires an external excitation of stable machining condition. Transient vibration of the perturbation is captured...

Robust stability analysis of turning is presented for flexible workpiece. The varying dynamic properties due to the material removal process is modelled by means of finite element method. The Frequency Response Function is traced along tool position. The results show significant change in the natural frequency and modal stiffness, which have strong...