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This paper aims to overcome some of the practical difficulties in assistive control of exoskeletons by developing a new assistive algorithm, called output feedback assistive control (OFAC) method. This method does not require feedbacks from force, electromyography (EMG) or acceleration signals or even their estimated values.

The presented controller uses feedbacks from position and velocity of the output link of series elastic actuators (SEAs) to increase the apparent integral admittance of the assisted systems. Optimal controller coefficients are obtained by maximizing the assistance ratio subjected to constraints of stability, coupled stability and a newly defined comfort measure.

The results confirm the effectiveness of using the inherent properties of SEAs for removing the need for extra controversial sensors in assistive control of 1 degree of freedom (1-DOF) SEA powered exoskeletons. The results also clearly indicate the successful performance of the OFAC method in reducing the external forces required for moving the assisted systems.

As the provided experiments indicate, the proposed method can be easily applied to single DOF compliantly actuated exoskeletons to provide a more reliable assistance with lower costs. This is achieved by removing the need for extra controversial sensors.

This paper proposes a novel assistive controller for SEA-powered exoskeletons with a simple model-free structure and independent of any information about interaction forces and future paths of the system. It also removes the requirement for the extra sensors and transforms the assistive control of the compliantly actuated systems into a simpler problem of position control of the SEA motor.

During drilling in coal mines, sticking of drill rod (referred to as SDR in this work) is a potential threat to underground safety. However, no practical measures to deter SDR have been developed yet. The purpose of this study is to develop an anti-SDR strategy using proportional-integral-derivative (PID) and compliance control (PIDC). The proposed strategy is compatible with the drilling process currently used in underground coal mines using drill rigs. Therefore, this study aims to contribute to the PIDC strategy for solving SDR.

A hydraulic circuit to reduce SDR was built based on a load-independent flow distribution system, a PID controller was designed to control the inlet hydraulic pressure of the rotation motor and a typical compliance control approach was adopted to control the feed force and displacement. Moreover, the weight and optimal combination of the alternative admittance control parameters for the feed cylinder were obtained by adopting the orthogonal experiment approach. Furthermore, a fuzzy admittance control approach was proposed to control the feed displacement. Experiments were conducted to test the effectiveness of the proposed method.

The experimental results indicated that the PIDC strategy was appropriate and effective for controlling the rotation motor and feed cylinder; thus, the proposed method significantly reduces the SDR during drilling operations in underground coal mines.

As the PIDC strategy solves the SDR problem in underground coal mines, it greatly improves the safety of coal mine operation and decreases the power cost. Consequently, it brings the considerable benefits of coal mine production and vast application prospects in other corresponding fields. Actual drilling conditions are difficult to accurately simulate in a laboratory; thus, for future work, drilling experiments can be conducted in actual underground coal mines.

The PIDC-based anti-SDR strategy proposed in this study satisfactorily controls the rotation motor and feed cylinder and facilitates the feed and rotation movements. Furthermore, the tangible novelty of this study results is that it improves the frequency response of the entire drilling system. The drilling process with PIDC decreased the occurrence of SDR by 50%; therefore, the anti-SDR strategy can significantly improve the safety and efficiency of underground coal mining.

Admittance control is a typical complaint control methodology. Traditionally, admittance control systems are based on a dynamical relationship described by Voigt model. By contrast, after changing connection of spring and damper, Maxwell model produces different dynamics and has shown better impact absorption performance. This paper aims to design a novel compliant control method based on Maxwell model and implement it in a robot catching scenario.

To achieve this goal, this paper proposed a Maxwell model based admittance control scheme. Considering several motion stages involved in one catching attempt, the following approaches are adopted. First, Kalman filter is used to process the position data stream acquired from motion capture system and predict the subsequent object flying trajectory. Then, a linear segments with parabolic blends reaching motion is generated to achieve time-optimal movement under kinematic and joint inherent constraints. After robot reached the desired catching point, the proposed Maxwell model based admittance controller performs such as a cushion to moderate the impact between robot end-effector and flying object.

This paper has experimentally demonstrated the feasibility and effectiveness of the proposed method. Compared with typical Voigt model based compliant catching, less object bounding away from end-effector happens and the success rate of catching has been improved.

The authors proposed a novel Maxwell model based admittance control method and demonstrated its effectiveness in a robot catching scenario. The author’s approach may inspire other related researchers and has great potential of practical usage in a widespread of robot applications.

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.

The purpose of this paper is to develop a spectral element modeling to predict electromechanical admittance in the surface-bonded piezoelectric wafer and beam structure considering temperature effects.

For modeling the beam, the axial and transverse vibrations of the beam have been considered, and temperature-dependent mechanical and electromechanical properties of piezoelectric wafer active sensor and aluminum have been analyzed. The influences of temperature effects on electromechanical admittance are investigated.

The results show that a frequency left shift and a decrease in amplitude of admittance in any natural frequencies with increasing temperature have been observed. The mechanism of these changes is discussed.

The numerical results may be considered helpful for structural health monitoring using electromechanical impedance technique.

The main aim of this study is the modelling of the interaction of on‐chip components with their electromagnetic environment.

The integrated circuit is decomposed in passive and active components interconnected by means of terminals and connectors which represent intentional and parasitic couplings of a capacitive and inductive nature. Reduced order models are extracted independently for each component.

The paper shows that one of the main theoretical problems encountered in the modelling of RF components is the difficulty to define a unique terminal voltage, independent of the integration path (this independence being a condition to allow the connection of the component in an electric circuit, where the voltage does not depend of the path shape). The concept of an electromagnetic circuit element that allows the interconnection between IC models is proposed as a solution for this drawback. The system is described either with EM field models, or by electric/magnetic circuits. By using the new concept of hooks, the EM interaction is described effectively with a reduced number of quantities.

Since hooks have a virtual character, their identification is the result of an optimization procedure. By increasing their number the model accuracy is improved as also is the computational effort. The optimal automatic identification of electric and magnetic hooks is the subject of further research. Currently, the hooks are placed manually.

The modelling of IC components with hooks is part of a new methodology that takes a layout description of typical RF functional blocks that will operate at RF frequencies up to 60 GHz and transform them into sufficiently accurate, reliable electrical simulation models, taking EM coupling and variability into account. This will decrease extra design iterations, over‐dimensioning or complete failures in the design cycle of RF‐IC.

For the first time, the concept of magnetic terminals is used to describe interactions in RF integrated circuits. These EM “hooks” are defined in mathematical terms, as proper boundary conditions. The concept of hooks is also new. The proposed modeling methodology for EM coupling is also new. The paper is useful for nEDA designers.

Purpose: The purpose of this chapter is to examine women’s college alumnae’s gender panics surrounding transgender admittance policies and negotiations on how to define the boundaries of the alumnae community in moments of these panics.

Methodology/Approach: I explore these negotiations by conducting a modified grounded theory approach of online discussion threads of one women’s college alumnae Facebook group from 2013 to 2016. These threads (39 threads; 2,812 comments) discuss transgender admissions policies at women’s colleges and the definition of woman more broadly.

Findings: I outline three strategies that define who belongs to a women’s college community in response to peers’ gender panics. First, I discuss the ways in which alumnae “call out hate” and label exclusionary peers as Trans Exclusionary Radical Feminists (TERFS). Second, I discuss the negotiated boundaries of who is included within the women’s college community. Finally, I focus on the recommended suggestions and expectations for fellow alumnae to be allies toward their trans peers.

Social Implications: These findings imply that feminist boundary negotiation is not only simply based on external threats, but can also be debated among members within the community.

Originality/Value of Study: This study highlights the nuances and strategies of boundary construction in regards to the social category of woman. I propose that researchers expand theorizations of gendered boundary negotiation to consider the ways in which boundaries are drawn not only as a form of panic and exclusion but also as a response to such panics to promote inclusivity and diversity.

The paper aims to focus on: implementation of the fast‐multipole method (FMM) to open perfect electric conductors (PEC) problems involving triangular type wire‐to‐surface junctions; investigation and analysis of the effect of wire‐to‐surface junction configuration on the conditioning of the linear systems; application of the preconditioning technique to improve the efficiency of the FMM scheme on such problems.

A complete set of formulations is proposed to evaluate the far‐field terms of the impedance matrix that represent the couplings between the wire‐to‐surface junction and standard wire and PEC surfaces. The formulations are derived in a convenient form suitable for the application of the FMM. An iterative scheme is adopted to estimate the condition number of the linear systems arising from open‐PEC problems with wire‐to‐surface junctions and to investigate the effect of wire‐to‐surface junction configuration on the conditioning of the linear systems. The Crout version of ILU (ILUC) preconditioning strategy is applied to improve the convergence rate of the iterative solver on such problems.

The solutions show that the proposed formulations have accurately evaluated the far‐field terms that represent the couplings between the wire‐to‐surface junction and standard wire and PEC surfaces. The investigation of the conditioning of open‐PEC problems with junctions shows that the effect of the wire‐to‐surface junction configuration induced to the conditioning of the linear systems is negligible. The convergence records of several open‐PEC problems involving wire‐to‐surface junctions show that the ILUC preconditioning strategy is suitable to apply to such problems, as it significantly improves the performance of the iterative solver.

The proposed FMM strategy can be applied to many practical large‐scale open‐PEC problems that involve wire‐to‐surface junctions, such as antenna arrays and electromagnetic compatibility problems, to effectively speed up the overall electromagnetic simulation progress and overcome the bottleneck associated with the dense impedance matrix of the method‐of‐moments.

The application of the FMM to open‐PEC problems that involve wire‐to‐surface junctions has yet to be reported, which has been addressed in this work. This work also investigates the conditioning of such problems and analyzes the effect of wire‐to‐surface junction configuration on the conditioning of the linear systems. In addition, the performance of the ILUC preconditioner on such problems has not been reported, which has also been included in this report.

The unknown current distribution (UCD), line leakage current density (LLCD) and other integral characteristics of a linear grounding structure (GS), shaped either as an arbitrary linear star (LS) or polygon (LP), are presented in this paper. The UCD of the GS is determined by numerical solving of system of integral equations of two‐potential (SIE‐TP). The GS is placed in homogeneous and isotropic earth and its integral characteristics are analysed in the power frequency domain.

The purpose of this paper is to offer a simulation method for predicting the impedance of machine windings at higher frequencies.

A transmission‐line model (TLM) is developed based on parameters calculated on the basis of electroquasistatic and magnetoquasistatic finite‐element (FE) model of the winding cross‐section.

The FE formulations for the low‐ and high‐frequency limits give acceptable results for the respective frequency ranges. An eddy‐current formulation is only accurate on a broader region when the FE mesh is sufficiently fine to resolve the skin depth.

The paper is restricted to frequency‐domain simulations.

The results of the paper improve the understanding of higher‐frequency parasitic effects in electrical drives with long windings.

The paper shows the limitations of the FE methods used for determining the parameters of the TLMs and remedies to avoid these.