Science Robotics, Volume 7, Issue 65, April 2022.

Science Robotics, Volume 7, Issue 65, April 2022.

Science Robotics, Volume 7, Issue 65, April 2022.

This paper proposes harnessing the aerokinetic energy in flue systems and it explores the ash deposition effect on flow-induced vibration energy harvesting performance. Bell-shaped and horn-like bluff bodies are designed to simulate different ash depositions on a conventional elliptic cylinder bluff body. Wind tunnel experiments were conducted to investigate the energy harvesting performance using

This paper proposes two significant developments of the Wittrick–Williams (W–W) algorithm for an exact wave propagation analysis of lattice structures based on analytical dynamic stiffness (DS) model for each unit cell of the structures. Based on Bloch’s theorem, the combination of both the DS and the W–W algorithm makes the wave propagation analysis exact and efficient in contrast to existing methods

Four-contact-point ball bearing (FCPBB), with a special double half inner ring structure, presents dynamic multi-point contact characteristics in service. The dynamic contact feature, such as 2-point, 3-point or even 4-point contact phenomena between balls and bearing raceway, lead to completely different bearing friction, heat generation and wear rates. Considering the oil film traction effect, the

This paper proposes a Bayesian framework based on particle filters for online fatigue damage diagnosis and prognosis for wind turbine blades (WTBs). The framework integrates theoretical and practical aspects with the purpose of developing a robust monitoring tool. Besides, a damage indicator based on identified modal frequencies of the WTB is defined to quantify the degree of damage to the monitored

As the prerequisite for obtaining the optimal demodulation frequency band (ODFB), the frequency band division model must be delicately constructed. The division models in existing methods of obtaining ODFB are vulnerable to the background noise and irrelevant components, which will cause an unsuitable demodulation frequency band. To improve the performance of frequency band division model, this paper

Pressure control of the electro-hydraulic brake-by-wire system (EHB) is of great significance in achieving precise braking maneuvers for the brake-by-wire vehicle. In this study, a high accuracy main cylinder pressure tracking method with exact performance boundary is proposed for the mainstream motor-booster EHB system. By considering the clearance in the mechanical transmissions, a more applicable

Energy is dissipated in engineering systems through a variety of different, typically complex, damping mechanisms. While there are several common damping models with physical interpretations, it is often necessary to examine noisy, experimental data in order to identify and fit the damping parameters. One class of methods fits the damping parameters based on the decay envelope of the signal’s peaks

Machine condition monitoring is an emerging research domain to use monitoring data to monitor machine conditions and prevent unexpected machine failures. In our previous study, the sum of weighted normalized square envelope was proposed as a generalized framework of some well-known sparsity measures including kurtosis, negative entropy, smoothness index, and Gini index. This framework revealed that

During the state monitoring and fault diagnosis of hydraulic control system, different kinds of sensors are used to collect fault signals. The arrangement of a limited number of sensors in the most reasonable positions of the hydraulic system, that is, to solve the problem on the optimal placement of sensors, is the key to improving efficiency of fault diagnosis. Aiming at fault diagnosis of hydraulic

A working wind turbine generates a large amount of multivariate time-series data, which contain abundant operation state information and can predict impending anomalies. The anomaly detection of the wind turbine nacelle that houses all of the generating components in a turbine have been challenging due to its inherent complexities, systematic oscillations and noise. To address these problems, this

Biomimetics adopted as a basis for underwater robotic design to enhance locomotion efficiency, maneuverability, and adaptability has shown an extraordinary vitality and enormous growth potential in the field of underwater robotics. However, most designs are focused on mimicry of a specific aquatic organism or its specific function. Biomimetic approaches to underwater robot design that incorporate combination

The machining stability is an essential prerequisite for achieving required dimensional accuracy and high-quality surface of the machined parts. The stability boundary will drift with the changing machining dynamic characteristics due to tool wear, cutting temperature increase, etc. The online milling stability prediction is of great significance for improving machining efficiency and surface quality

The problem of robust pole placement in active structural vibration control by the method of receptance is considered in this paper. Expressions are derived for the eigenvalue sensitivities to parametric perturbations, which are subsequently minimised to improve performance robustness of the control of a dynamical system. The described approach has application to a vibrating system where variations

The image quality of an atomic force microscope highly depends on the tracking performance of the lateral X–Y axis scanner. To reduce the requirement for accurate system models, this article describes a method based on Model-free Repetitive Control (MFRC) for high performance control of fast triangular trajectories in the X-axis while simultaneously achieving coupling compensation from the X-axis to

Science Robotics, Volume 7, Issue 64, March 2022.

Science Robotics, Volume 7, Issue 64, March 2022.

Science Robotics, Volume 7, Issue 64, March 2022.

Science Robotics, Volume 7, Issue 64, March 2022.

This paper proposes a novel inerter-based damper, termed tuned inertial mass electromagnetic damper (TIMED), to mitigate seismic responses of civil structures. The TIMED consists of three elements, i.e., an inerter, a spring, and an electromagnetic damper, all assembled in parallel. Firstly, a theoretical model is proposed for predicting the damper force and the frequency response of the TIMED, which

A primary structure attached by a nonlinear energy sink (NES) moving vertically under a Gaussian white noise excitation is investigated. This paper demonstrates the stochastic responses and vibration suppression with emphasis on the effects of the weights. Four-dimensional state space equations which consider or ignore the weights in the vertical direction are given. Numerical probability density functions

Mechanical equipment such as wind turbines often operates under time-varying working conditions (TVWC). The vibration signals collected from their key rotating components, such as bearings and gears, are often affected by TVWC. In this situation, eliminating the influence of working conditions is the key to effectively implementing end-to-end intelligent diagnosis of rotating machinery (RM). This paper

As structural dynamics and acoustics form increasingly important aspects of technical products, gaining detailed insight into a system’s resonating behavior is crucial during the development process. In jointed structures, a system’s damping and thus its structural dynamic behavior is mainly influenced by the damping within the joint rather than the material damping of the individual parts. Various

In this paper, the band gap (BG) properties of the phononic crystal (PC) involving bonding layers described by the ring-like structure are investigated. Based on the generalized Maxwell model, the effect of the bonding layers on BGs dependence is analyzed. Combing the numerical simulation and physical experiment, BG characteristic of the ring-like PC structure involving bonding layers is proved to

We share our experience and lessons learned from participating in the Agile Robotics for Industrial Automation Competition (ARIAC), 2021. We won 1st place in the finals and benefited from an agent-based architecture, task assignment strategy, and modular software programming design method based on the Unified Modeling Language.

Personalized products have gradually become the main business model and core competencies of many enterprises. Large differences in components and short delivery cycles of such products, however, require industrial robots in cloud manufacturing (CMfg) to be smarter, more responsive and more flexible. This means that the deep learning models (DLMs) for smart robots should have the performance of real-time

Nonlinear energy sink (NES) can be used to reduce the forced vibration of the primary system. Many different kinds of periodic responses of the linear system coupled with NES have been presented in the literature. In order to reveal all kinds of periodic responses of the NES system on given parameter planes, this study intends to achieve the classification of different kinds of periodic responses of

The magnetically suspended flywheel (MSFW) could output gyroscopic moment for attitude control. The conical magnetic bearing (MB) with cone-shape airgap is designed to stably suspend the rotor on three translational degrees of freedom (DOFs), and the Lorentz-force MB with long torque-arm could actively deflect the rotor around radial axes on two DOFs. Firstly, the force models of the conical MB are

In this paper, a new method is proposed to enhance the performance of auxetic nonlinear piezoelectric energy harvesting by increasing the unit cell number of auxetic structure. This method is validated through an auxetic nonlinear piezoelectric energy harvester, which combines a clamped–clamped beam with multiple rotating square unit cells. On one hand, the key structural parameter of the square rotating

In this paper, we will give a short overview of the theory of the random decrement (RD) technique invented around 1970 by Henry Cole for structural response analysis, and introduced in the seventies as part of the Ibrahim time domain identification technique. The RD technique introduced by Cole and Ibrahim was an algorithm with uncertain meaning until Vandiver et al. and later Brincker et al. presented

This paper presents a novel long-stroke fast tool servo (FTS) system with counterbalance and its application to the diamond machining of microstructured surfaces. The FTS system is driven by a voice coil motor and guided by air bearings. A hybrid control algorithm which combines PID control, sliding mode control and feed-forward control was specifically designed for the system and ensures that it has

This paper introduces a fast Gibbs sampler for solving a fully Bayesian problem in operational modal analysis. The proposed method is able to infer modal properties from the FFT of well-separated modes. System identification and related uncertainties are captured by a posterior distribution. The classical resonance description is wrapped into a hierarchical probabilistic model. The model is sampled

Numerical simulation plays an vital role in mechanical engineering, as it allows the prediction of the mechanical behavior of a component, contributing to the improvement of its performance and the optimization of the design. However, before using the numerical model’s valuable information, its reliability must be verified in a process called validation. Validation is usually carried out experimentally

A wealth of complex structures with interconnected joints such as steel truss bridges and warehouses commonly exist in civil engineering, while they are easily subjected to joint faults like bolt loosening, breathing crack and chemical corrosion during their service, which would seriously affect structures’ safety, durability and reliability. Therefore, diagnosis of joint faults, especially at an early