The fundamental objective in developing variable stiffness actuators is to enable the actuator to deliberately tune its stiffness. This is done through controlling the energy flow extracted from internal power units, i.e., the motors of a variable st...
This paper proposes a variable stiffness joint based on a symmetrical crank slider mechanism (SCM-VSJ). Firstly, the mechanical design and the working principle of the variable stiffness joint is described, and its stiffness regulation characteristic...
To improve collision safety in robot–human collaborative applications, increasing attention has been paid to rotational variable stiffness actuators. A new rotational variable stiffness actuator, which works in two stages, is proposed for hybri...
In this paper, a novel variable stiffness mechanism is presented, which is capable of achieving an output stiffness with infinite range and an unlimited output motion, i.e., the mechanism output is completely decoupled from the rotor motion, in the z...
According to the experience of nurses and physiotherapists, the abdomen of constipated people becomes softer after abdominal massage. However, the relationship between the decrease in abdominal stiffness and the benefits of abdominal massage has not...
Vibrations often result in fatigue breakage in quadcopter flight operations. Reducing the vibration effect is the main important issue for quadcopter flight. Enhanced dynamic stiffness is required in the quadcopter control system for the vibration re...
Cell rigidity sensing—a basic cellular process allowing cells to adapt to mechanical cues—involves cell capabilities exerting force on the extracellular environment. In vivo, cells are exposed to multi-scaled heterogeneities in the mechan...
The lower–extremity system acts like a spring in the running stance phase. Vertical stiffness (Kvert) and leg stiffness (Kleg) reflect the whole–body center of mass (COM) and leg–spring system loading and response in running, while...
The determination of elastic modulus (E) and hardness (H) relies on the accuracy of the contact area under the indenter tip, but this parameter cannot be explicitly measured during the nanoindentation process. This work presents a new approach that c...
Variable-stiffness actuators can flexibly adjust the overall or local stiffness of a structure, thus enabling reconstruction, adaptation, and locking capabilities that can meet a wide range of task requirements. However, the programmable design and m...
The torsional stiffness of the reducer is commonly assumed to be static and tested using the hysteresis curve method. However, practical engineering experience shows that the torsional stiffness is dynamic rather than static, and the hysteresis curve...
Adipokines are active molecules with pleiotropic effects produced by adipose tissue and involved in obesity-related metabolic and cardiovascular diseases. Arterial stiffness, which is a consequence of arteriosclerosis, has been shown to be an indepen...
Under long-term horizontal cyclic loading, the evolution characteristics of the loading and unloading stiffness of piles are an important representation of pile–soil interaction. However, research in this area is limited, particularly regarding...
This review outlines the latest methods and innovations for assessing arterial stiffness, along with their respective advantages and disadvantages. Furthermore, we present compelling evidence indicating a recent growth in research focused on assessin...
The development of stiffness theory is constrained by its contradiction with engineering experience. Several easily overlooked details of stiffness theory were clarified, and a qualitative evaluation formula for the risk of coal burst was provided. T...
Synthetic ropes are increasingly favored for use in offshore systems. Accurate predictions of the coupled hydrodynamic performance and structural response of offshore structures depends on a thorough understanding of the nonlinear characteristics of...
Background: The role of arterial stiffness in the pathogenesis and clinical outcome of heart failure (HF) patients has to be clarified. The aim of this study was to evaluate the prognostic role of arterial stiffness in HF patients discharged after ac...
In this paper, an optimal PID controller is introduced for an antagonistic variable stiffness actuator (AVSA) based on Hammerstein models. A set of Hammerstein models is developed for the AVSA using the voltage difference method. For each stiffness l...
This article analyzes the influence of the initial deflection of the flat layers on the bending stiffness (BS) of honeycomb paperboards and presents two methods for its calculation. Both methods allow for the determination of BS in the main direction...
The marine elastomeric bearing consists of an elastomer and several reinforcing inserted plates. Unlike land bearings that are to absorb high-frequency vibration during earthquakes, offshore elastomeric bearings are to support topside-module weight w...
An exoskeleton is a wearable device with human–machine interaction characteristics. An ideal exoskeleton should have kinematic and kinetic characteristics similar to those of the wearer. Most traditional exoskeletons are driven by rigid actuato...
This article presents the results of research on the change in torsional stiffness of two rectangular profiles, arranged one on top of the other, which were permanently connected at their ends. The flat bars were expanded in the middle of their activ...
The hybrid aircraft model support mechanism is subjected to six directional forces in the experiment, and high spatial stiffness requirement of the parallel part is the guarantee for the stability of the aircraft model. The purpose of this paper is t...
In order to improve the stiffness of flexible robots, this paper proposes a variable-stiffness elastic actuator. The actuator integrates the working principles of a pneumatic drive, wedge structure, and particle blockage. The anti-tensile stiffness o...
This paper investigates the effect of a gear tooth peeling on meshing stiffness of involute gears. The tooth of the gear wheel is symmetric about the axis, and its symmetry will change after the gear spalling, and its meshing stiffness will also chan...
A new stiffness measurement method is proposed that utilizes the lateral deformation profile of an object under indentation. The system consists of a force measurement module between a pair of equidistant touch sensing modules. Unique feature of the...
When a beam twists, localized flexural deformation in the plate occurs at the connection between the corrugated plate and the beam, resulting in a reduction in the bracing stiffness of the corrugated plate. To accurately assess the bracing stiffness...
This paper presents new findings concerning a hand-held stiffness probe for the medical diagnosis of abnormalities during palpation of soft-tissue. Palpation is recognized by the medical community as an essential and low-cost method to detect and dia...
MEMS stiffness-tunable devices, owing to their low resonant frequency and high sensitivity, have been widely adopted in fields such as biological force sensing, vibration sensing, and inertial sensing. However, traditional stress-effect-based stiffne...
Stiffness is the main internal excitation of gear system vibration and is the basis for studying the static and dynamic characteristics of the system. Based on the relationship between thermal stress and strain in plane strain theory and combined wit...
In response to challenges like the complexity and limited scalability of existing variable stiffness joints, a novel variable stiffness joint, based on leaf spring elements, is introduced in this paper. The joint stiffness can be adjusted in real tim...
This work highlights how the stiffness index, which is often used as a measure of stiffness for differential problems, can be employed to model the spread of fake news. In particular, we show that the higher the stiffness index is, the more rapid the...
Oceans, which cover more than 70% of Earth’s surface, are home to vast biological and mineral resources. Deep-sea exploration encounters significant challenges due to harsh environmental factors, including low temperatures, high pressure, and c...
Structural design often includes geometrically nonlinear analysis to reduce structural weight and increase energy efficiency. The full-order finite element model can perform the geometrically nonlinear analysis, but its computational cost is expensiv...
The choice on which type of cantilever to use for Atomic Force Microscopy (AFM) depends on the type of the experiment being done. Typically, the cantilever has to be exchanged when a different stiffness is required and the entire alignment has to be...
In order to adapt to complex and changeable mechanical conditions and make the deformable mechanisms perform well statically and dynamically, variable stiffness joints have been studied extensively. The variable stiffness actuator is the key driving...
The aorta and aortic wall have a complex biological system of structural, biochemical, biomolecular, and hemodynamic elements. Arterial stiffness could be considered a manifestation of wall structural and functional variations, and it has been reveal...
The non-variable stiffness of the flexible hinge in the fast-steering mirror (FSM) cannot adapt to varying load demands. To address this issue, this paper presents an innovative variable-stiffness rotational mechanism designed for use with FSMs. Firs...
Arterial stiffness is a risk factor for cardiovascular disease that is affected by diet. However, research understanding how these dietary risk factors are related to arterial stiffness during childhood is limited. The purpose of this review was to d...
In the medical field and in soft robotics, flexible devices are required for safe human interaction, while rigid structures are required to withstand the force application and accuracy in motion. This paper aims at presenting controllable stiffness m...
Arterial stiffness is a recognized predictor of cardiovascular morbidity and death. It is an early indicator of arteriosclerosis and is influenced by numerous risk factors and biological processes. The lipid metabolism is crucial and standard blood l...
Soft fingertips have distinct intrinsic features that allow robotic hands to offer adjustable and manageable stiffness for grasping. The stability of the grasp is determined by the contact stiffness between the soft fingertip and the object. Within t...
Large-scale components usually have complex structures with high local stiffness, and the holes on them are required to be machined with high precision, which makes it important and challenging to study how to efficiently and precisely drill in the l...
Due to their high flexibility, large workspace, and high repeatability, industrial robots are widely used in roughing and semifinishing fields. However, their low machining accuracy and low stability limit further development of industrial robots in...
The low stiffness of robots significantly limits their applicability within the aerospace assembly and manufacturing sectors. The majority of existing research focuses on optimizing robot posture; however, the efficacy of these approaches is constrai...
To achieve laminates with constant bending stiffness to match the high precision requirement of optical systems made of carbon fiber reinforced plastic (CFRP), a new method, the normalized direction factor of bending stiffness (NDFBS), is proposed ba...
This paper takes a four-point contact ball bearing of a wind turbine as the research object, analyzes the force and deformation relationship under the combined action of axial load and radial load, obtains the load distribution of rolling elements, a...
This paper proposes a quasi-zero stiffness (QZS) isolator based on an inclined trapezoidal beam to explore its advantages in low-frequency passive vibration isolation. The nonlinear stiffness of the inclined trapezoidal beam due to the buckling effec...
Industrial robots are regularly being employed for machining tasks. As a key machining parameter, dynamic stiffness has a significant influence on robotic machining performance. This paper examines two experimental approaches for obtaining the dynami...
This study presents an integrated stiffness modeling and evaluation framework for an orthopedic surgical robot, aiming to enhance cutting accuracy and operational stability. A comprehensive stiffness model is developed, incorporating the stiffness of...
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