## 1 Robotics and Vibration Mechanics  
Robotics and vibration mechanics are among the main research areas in mechanical engineering. Robotics includes the design, construction, control, operation, and trajectory planning of autonomous and automatic machines that can substitute or help humans in several tasks in manufacturing processes, dangerous situations, and even in the domestic environment. On the other hand, vibration mechanics investigates the dynamic effects that can arise when flexible mechanical systems are excited by an external time-varying disturbance, or set in motion with an initial input and allowed to vibrate freely.  
The growing interest and development of lightweight robots and mechanisms have led to the study and investigation of several aspects of both robotic systems and mechanical vibrations strictly related between them. Indeed, flexibility may lead to undesired mechanical vibrations, especially when lightweight systems performing high-speed operations are considered [1]. Therefore, proper structural design, modelling, and control are required to correctly steer the system during operation.  
Compliant mechanisms and robots are characterized by the bending of flexible members. The advantages of this kind of mechanism include, for instance, low weight, low friction, compactness, and reduced power consumption. On the other hand, challenges are mainly related to their nonlinear motion, complex modelling and control.  
When dealing with compliant mechanisms, dynamic models become fundamental to predict not only the motion, but also forces and torques acting on the system and those required by the actuators. Several approaches for the dynamic modelling of flexible multibody systems have been developed over the years. Notable formulations include the Floating Frame of Reference [2], the Absolute Coordinate Formulation [3], the Absolute Nodal Coordinate Formulation [4], and the Equivalent Rigid-Link System [5; 6; 7].  
Compliant mechanism design methods encompass finite element analysis, topology optimization, and pseudo-rigid-body model methods [8]. Design methods can include, for instance, the modal modification of a predefined mechanical system [9], the assignment of proper eigenfrequencies [10], as well as vibration absorption techniques [11]. A further approach that exploits the elastic behavior of a mechanism is the natural motion [12; 13], which allows for energy saving in cyclic tasks by properly designing compliant elements [14], and by considering the free vibration response of the system [15].  
When dealing with robotic systems and mechanisms in which flexibility cannot be neglected, control is certainly an important and challenging aspect, since a clever control strategy is needed to avoid potential vibration-induced issues [16; 17]. Several control strategies have been developed over the years, for instance, adaptive control, feedforward control, model-based control, nonlinear control, optimal control, and PID, among others. However, the problem of control of flexible multibody systems is still an open and challenging field of investigation.  
This Special Issue invited researchers to present recent advances and technologies in the fields of robotics and vibration mechanics. Suitable topics included, but were not limited to, the following: robotics and autonomous systems, mechanical vibrations and noise, kinematic and dynamic modeling of robotic systems, path and trajectory planning, automatic control systems, flexible multibody systems, collaborative robotics, design and optimization of robotic and mechatronic systems, mechanisms design, and manufacturing systems.