We are honoured to present you the Special Issue prepared on the basis of selected works presented at the 15^th International Conference “Dynamical Systems – Theory and Applications”, from 2^nd to 5^th December 2019 at Lodz, Poland.

The DSTA conference has 25 years of history. It takes place every two years in Lodz, which is the third‐largest city in Poland. It is organized by the staff of the Department of Automation, Biomechanics and Mechatronics of the Lodz University of Technology under the patronage of the Committee of Mechanics of the Polish Academy of Sciences. The scope of the DSTA conference is to provide a common ground for the exchange of new ideas and the results of recent scientific achievements, both theoretical and application in the field of modern dynamical systems.

The last, 15^th conference was attended by over 213 scientists from 40 countries around the world. The participants and the Scientific Committee are at the forefront of the world in the fields of mechanics, mechatronics, computer science, mathematics, and biomechanics. Over 200 works qualified to be presented at the conference. The authors of the best of them were given the opportunity to publish their extensions in over 10 reputable scientific journals and books published by global publishing houses.

The articles in this Special Issue deal with the dynamics of nonlinear systems and have been reviewed in accordance with the standards of the ZAMM journal. The topics covered in the papers concern analysis of vibrations, vibration damping, energy harvesting, and friction phenomena in vehicles. Now, we provide a brief overview of all included papers.

Walentyński et al. studied problems of dynamics of structures under the project called Vibration Busters realized in the formula of Project‐Based Learning. Students and supervisors from three different faculties: construction, mathematics and mechatronics participated in the project. They conducted numerical and experimental studies of the frame structure forced by vibrations generated by electric motors. Thanks to the project, both students and supervisors gained new experience and scientific and social skills.

Kęcik developed an absorber/harvester system consists of pendulum tuned mass and semi‐active suspension. The mitigation of the vibration has been analysed numerically as well as harvesting energy process. The proper configuration of the system's parameters may improve the energy harvesting combined with vibration mitigation.

Selyutskiy et al. investigated the dynamics of the system consists of piezoelements and double aerodynamic pendulum. The stability of the trivial equilibrium position was studied. Numerical computations show that attracting limit cycle can be achieved by ensuring certain parameters of the system. The presented system might be applied as a mini wind power generator.

Nguyen‐Thai et al. studied the origin of the unwanted high frequencies sound generated by vehicles’ brakes. The mechanical linear analysis has been performed for the so‐called brake squeal. In result, it turned out that the damping coefficient and the gyroscopic terms affect the stochastically reinforced self‐excitation. The analysis has shown that this hypothesis should be taken into account in a classical explanation of brake sqeal.

Miroslaw developed a pneumatic wheel model with plastic elements. The new model is similar to the Pacejka brush model as well as Dhal and LuGre models. The model is easier and more intuitive due to the introduction of elastic elements between brushes. The method of force loss has been used to build dynamic models, which were numerically simulated and compared with experimental results.

We are extremely happy that we were able to publish this Special Issue and we dedicate it to all those who contributed with their efforts to publish it.

我们很荣幸为您呈现的15呈现入选作品的基础上编制专刊^届国际大会“动力系统-理论与应用”，从2^次至5^日在波兰的罗兹2019十二月。

DSTA会议已有25年的历史。它每两年在罗兹（波兰第三大城市）举行。它是由罗兹理工大学自动化，生物力学和机电一体化系的工作人员组织的，由波兰科学院力学委员会赞助。DSTA会议的范围将为交流新的思想和最新的科学成果（包括现代动力系统领域的理论和应用）提供一个共同的基础。

最近的^第15^届会议来自世界40个国家的213多名科学家参加了会议。参与者和科学委员会在力学，机电一体化，计算机科学，数学和生物力学领域处于世界前列。有200多种作品有资格在会议上发表。他们中最好的作者有机会在全球出版社出版的10多种著名科学期刊和书籍中发表其扩展文章。

本期特刊中的文章涉及非线性系统的动力学，并已根据ZAMM期刊的标准进行了审阅。论文涵盖的主题涉及车辆振动，振动阻尼，能量收集和摩擦现象的分析。现在，我们提供所有包含论文的简要概述。

Walentyński等。研究了在基于项目的学习公式中实现的名为“振动克星”项目下的结构动力学问题。来自建筑，数学和机电一体化三个不同系的学生和主管参加了该项目。他们对由电动机产生的振动强迫的框架结构进行了数值和实验研究。由于该项目，学生和指导者都获得了新的经验以及科学和社会技能。

肯奇克开发了一种减震器/收割机系统，该系统由摆调质量和半主动悬架组成。振动的缓解已通过数值分析以及能量收集过程进行了分析。系统参数的正确配置可以改善与振动减轻相结合的能量收集。

Selyutskiy等。研究了由压电元件和双气动摆组成的系统动力学。研究了微不足道的平衡位置的稳定性。数值计算表明，通过确保系统的某些参数可以实现吸引极限循环。所提出的系统可以用作小型风力发电机。

阮泰等。研究了车辆刹车产生的有害高频声音的起源。已对所谓的制动尖叫进行了机械线性分析。结果表明，阻尼系数和陀螺项影响了随机增强的自激。分析表明，在对制动响声的经典解释中应考虑这一假设。

Miroslaw开发了带有塑料元件的充气轮模型。新模型类似于Pacejka画笔模型以及Dhal和LuGre模型。由于在笔刷之间引入了弹性元素，因此该模型更加简单直观。力损失法已用于建立动态模型，并对其进行了数值模拟并与实验结果进行了比较。

我们很高兴能够出版本期特刊，并将其献给所有为出版该刊物做出贡献的人们。