Roland Lachmayer

Dr. Roland Lachmayer

orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
4 October 2022 in Sensors
Verified
Journal Article
Open access
PDF file
ZDZhuoqun Dai
Zhuoqun Dai
AWAlexander Wolf
Alexander Wolf
PLPeer-Phillip Ley
Peer-Phillip Ley
TGTobias Glück
Tobias Glück
MSMax Caspar Sundermeier
Max Caspar Sundermeier
RLRoland Lachmayer
Roland Lachmayer
Light detection and ranging (LiDAR) are fundamental sensors that help driving tasks for autonomous driving at various levels. Commercially available systems come in different specialized design schemes and involve plenty of specifications. In the literature, there are insufficient representations of the technical requirements for LiDAR systems in the automotive context, such as range, detection quality, resolving power, field of view, and eye safety. For this reason, the requirements above require to be derived based on ADAS functions. The requirements for various key LiDAR metrics, including detection range, field of view, angular resolution, and laser safety, are analyzed in this paper. LiDAR systems are available with various radiation patterns that significantly impact on detection range. Therefore, the detection range under various radiation patterns is firstly investigated in this paper. Based on ADAS functions, the required detection range and field of view for LiDAR systems are examined, taking into account various travel speeds to avoid collision and the coverage of the entire lane width. Furthermore, the angular resolution limits are obtained utilizing the KITTI dataset and exemplary 3D detection algorithms. Finally, the maximum detection ranges for the different radiation patterns are compared under the consideration of derived requirements and laser safety.

25 July 2023 in Heliyon
Verified
Journal Article
Open access
IMIna Meyer
Ina Meyer
MOMarcus Oel
Marcus Oel
TETobias Ehlers
Tobias Ehlers
RLRoland Lachmayer
Roland Lachmayer
Additive manufacturing (AM) can be used to produce multi-material parts in which the material can be varied voxel-wise in all three spatial directions. This means that the paradigm of the homogeneous material can be abandoned and local effects such as heat conduction or damping can be selectively adjusted in the part. Recently, continuous development of machine technology has allowed the production of multi-metal materials in laser powder bed fusion (PBF-LB/MM). Compared to other additive manufacturing processes for multi-material production, this allows greater design freedom and detail accuracy to be realized. However, due to the novel character of multi-material manufacturing in PBF-LB, the process knowledge for successful and reproducible fabrication is currently lacking. This paper focuses on establishing design guidelines for manufacturing the material pairing of stainless steel 316L (1.4404) and copper alloy CuCrZr (CW106C). The article is accompanied by the development of a specific process chain. As a result of this work, design guidelines for multi-material parts are available for the first time, in regard to arrangement, size, overhangs, economy, powder quality and laser scanning.

8 November 2019 in Journal of Mechanical Design
Verified
Journal Article
Closed access
PDF file
JHJennifer Hackl
Jennifer Hackl
DKDieter Krause
Dieter Krause
KOKevin Otto
Kevin Otto
MWMarc Windheim
Marc Windheim
SMSeung Ki Moon
Seung Ki Moon
RLRoland Lachmayer
Roland Lachmayer

21 February 2022 in Applied Sciences
Verified
Journal Article
Open access
PDF file
TETobias Ehlers
Tobias Ehlers
RLRoland Lachmayer
Roland Lachmayer
Additively manufactured particle dampers can significantly improve component damping. However, if designed incorrectly, the damping can be worsened. For the design of additively manufactured particle dampers, there are not yet sufficient design rules and models to describe the effect due to numerous design parameters. The research question answered in this paper describes how the effect of particle damping can be characterised as a function of excitation force and excitation frequency for different cavity sizes. To characterise the effect of particle damping, a 33 full factorial test plan is constructed, and the damping is determined experimentally. It is shown that the damping can be reliably evaluated with the circle-fit method. The effect of particle damping is investigated for beams made of AlSi10Mg, 1.2709 and Ti6Al4V. As a result, a positive effect of the particle damping in a frequency range from 500 to 30,000 Hz and partly up to the 9th bending mode can be proven. It is shown that, for the first bending mode, there is an optimum at approx. 2000 Hz. For the optimum, the increase of the damping for the tool steel 1.2709 to 28 and for the aluminium alloy AlSi10Mg to 18 can be proven.

12 February 2016 in Advanced Optical Technologies
Verified
Journal Article
Closed access
GKGerolf Kloppenburg
Gerolf Kloppenburg
AWAlexander Wolf
Alexander Wolf
RLRoland Lachmayer
Roland Lachmayer
The introduction of adaptive front lighting systems for vehicles has increased road safety and drivers’ comfort significantly within the last years. A next step in this development is the realization of higher resolution systems to further increase the functionality of vehicle headlamps toward fully adaptive front lighting systems. In this paper, we present a short overview on highly dynamic front lighting systems and the essential technologies for their realization. Different approaches are compared and evaluated regarding their applications for headlamp systems. As an example for on-road projection systems, a laser-based scanning unit is set up and evaluated.

Verified
Journal Article
Open access
PDF file
RLRoland Lachmayer
Roland Lachmayer
Bernd-Arno BehrensBernd-Arno Behrens
Bernd-Arno Behrens
TETobias Ehlers
Tobias Ehlers
PMPhilipp Müller
Philipp Müller
PAPhilipp Althaus
Philipp Althaus
SHSven Hübner
Sven Hübner
The deep-drawability of a sheet metal blank is strongly influenced by the tribological conditions prevailing in a deep-drawing process. Therefore, new methods to influence the tribology represent an important research topic. In this work, the application of a process-integrated lubrication in a deep-drawing process is investigated. Most promising geometries of the lubrication channels and outlet openings are first identified by means of numerical simulation at the example of a demonstrator process. Cylindrical test specimens with the specified channel geometries are additively manufactured and installed in a strip drawing test stand. Additive manufacturing enables the possibility of manufacturing complex channel geometries which cannot be manufactured by conventional methods. A hydraulic metering device for conveying lubricant is connected to the cylindrical test specimens. Thus, hydraulically lubricated strip drawing tests are performed. The tests are evaluated according to the force curves and the fluid mechanical buildup of pressure cushion. The performance of process-integrated lubrication is thus analyzed and evaluated. By means of a coupled forming and SPH simulation, the lubrication channels could be optimally designed. From the practical tests, it could be achieved that the drawing force decreases up to 27% with pressure cushion build up. In this research, a hydraulic lubrication in the area of highest contact normal stresses is the most optimal process parameter regarding friction reduction.