1,720,968 research outputs found
Scalable Inflatable Origami Robot Modules With Proprioceptive Closed-Loop Shape Control
No full textThis paper introduces a novel pneumatic origami module that embeds a proprioceptive closed-loop shape control through seamless sensor-hardware integration. Each module incorporates a spring along the stretchable airflow passage in conjunction with an individual solenoid valve, enabling intrinsic proprioceptive sensing via inductance measurement while maintaining pneumatic and mechanical reliability. The compact module, measuring 40 x 80 x 35 mm and weighing 55 g, features an adjustable height range of 29 to 71 mm under -25 to 25 kPa pressure. Experimental validation confirmed the notable performance of the module, with a consistent inflation time under various assembly combinations, a maximum extension force of 80.37 N, a low sensing hysteresis error of 7.58%, and sufficient durability to withstand 5,000 activation cycles. The resulting module assembly enables closed-loop shape control in both individual and synchronized multi-module operations, eliminating the need for external sensor attachments and demonstrating a highly responsive, precise, and adaptive shape-morphing process. This compliant, controllable, and straightforward module can serve as an unprecedented foundation for shape-programmable embodied intelligence in emerging autonomous robotic systems.
Design of a Flexible High-Density Surface Electromyography Sensor
No full textIn recent years, high-density surface electromyography (HD-sEMG) has shown promising advantages in many robotics applications. Using HD-sEMG can not only reduce the sensitivity of the sensor position on the muscle belly but can also facilitate the acquisition of more muscle activity information due to spatial sampling. As current commercial HD-EMG systems use stationary amplifiers, leading to bulky measurements and poor portability, the interest in developing an HD-EMG sensor has increased. However, the insufficient electrode density and complicated fabrication process are challenges to overcome. In this paper, we propose a flexible HD-EMG sensor with an on-board amplifier capable of a density level of 0.53 channel/cm2, higher than those in previous works. First, we investigated the effects of different sensor parameters (i.e., the electrode material, the inter-electrode distance (IED) and the size of the electrode) on the measured signal quality. Second, a low-cost, easily fabricated, easily customized HD-EMG fabrication method was proposed based on the selected sensor parameters with a signal-to-noise ratio (SNR) comparable to those of commercial sensors. Finally, we applied a muscle activation estimation algorithm to validate the feasibility of the designed HD-EMG sensor, showing higher estimation accuracy levels. The results here demonstrate that the designed HD-EMG sensor can be used as an effective human-machine interface for robotics applications
Development of a High-SNR Stochastic sEMG Processor in a Multiple Muscle Elbow Joint
No full textIn the robotics and rehabilitation engineering fields, surface electromyography (sEMG) signals have been widely studied to estimate muscle activation and utilized as control inputs for robotic devices because of their advantageous noninvasiveness. However, the stochastic property of sEMG results in a low signal-to-noise ratio (SNR) and impedes sEMG from being used as a stable and continuous control input for robotic devices. As a traditional method, time-average filters (e.g., low-pass filters) can improve the SNR of sEMG, but time-average filters suffer from latency problems, making real-time robot control difficult. In this study, we propose a stochastic myoprocessor using a rescaling method extended from a whitening method used in previous studies to enhance the SNR of sEMG without the latency problem that affects traditional time average filter-based myoprocessors. The developed stochastic myoprocessor uses 16 channel electrodes to use the ensemble average, 8 of which are used to measure and decompose deep muscle activation. To validate the performance of the developed myoprocessor, the elbow joint is selected, and the flexion torque is estimated. The experimental results indicate that the estimation results of the developed myoprocessor show an RMS error of 6.17[%], which is an improvement with respect to previous methods. Thus, the rescaling method with multichannel electrodes proposed in this study is promising and can be applied in robotic rehabilitation engineering to generate rapid and accurate control input for robotic devices
Pneumatic AFO Powered by a Miniature Custom Compressor for Drop Foot Correction
No full textFor active AFO applications, pneumatic remote transmission has advantages in minimizing the mass and complexity of the system due to the flexibility in placing pneumatic components and providing high back-drivability via simple valve control. However, pneumatic systems are generally tethered to large stationary air compressors, which greatly limit the practical daily usage. In this study, we implemented a wearable custom compressor that can be worn at the trunk of the body and can generate up to 1050 kPa of pressurized air to power an unilateral active AFO for dorsiflexion (DF) assistance of drop-foot patients. In order to minimize the size and weight of the custom compressor, the compression rate of the custom compressor was optimized to the rate of consumption required to power the active AFO. The finalized system can provide a maximum assistive torque of 9.8 Nm at a functional frequency of 1 Hz and the average resistive torque during free movement was 0.03 Nm. The system was tested for five hemiplegic drop-foot patients. The proposed system showed an average improvement of 12.3 degrees of ankle peak dorsiflexion angle during the mid to late swing phase.
광학식 토크 센서를 이용한 조인트 임피던스 제어 구현
Full text link최근 서비스 로봇들은 사람과 로봇이 같은 작업 공간에 있기 때문에 로봇과 사람 사이의 안전성을 보장해 주는 것이 필수적이다. 임피던스 제어가 안전성을 보장하기 위해 자주 쓰이고 있다. [1]-[2] 임피던스 제어에 자주 쓰이고 있는 힘/토크 센서로는 스트레인 게이지 방식이 있다. 스트레인 게이지방식은 선형성이 좋고 분해능이 높아 많이 쓰이고 있는 방식이나 스트레인 게이지를 붙이기 어렵고 추가적인 앰프가 필요하여 센서의 비용이 비싸다. 그에 비해 광학식 토크 센서는 제조과정이 간단하고 앰프가 불필요하여 더 저렴한 센서를 만들 수 있다. 일반적으로 광학식 토크 센서의 성능이 스트레인 게이지보다 떨어진다. 하지만 최근 서비스 로봇 분야에서 저렴한 매니퓰레이터에 대한 수요가 늘고 있다. 따라서 제조하기 쉽고 센서의 비용이 저렴한 광학식 토크 센서를 사용하여 임피던스 제어에 적용하는 연구들이 진행되고 있다. [3] 따라서 본 논문에서는 광학식 토크 센서를 개발하고 이것을 이용하여 임피던스 제어를 구현하려고 한다
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
가변 반경 기어와 고출력 토크 모터에 의한 자기안정화 가변 강성 구동 시스템의 개발
No full text학위논문(박사) - 한국과학기술원 : 기계공학과, 2019.2,[v, 88 p. :]In robotics, high mechanical impedance, resolution of sensors, and computing bandwidth have been desirable aspects for feedback control to obtain stability and better performance. In contrast, the human body is physically inferior to man-made systems in terms of feedback control due to low mechanical impedance, resolution of sensors and long signal transmission delay. Nevertheless, humans can achieve not only stable motion generation but also robust and adaptive control ability with respect to uncertain environment. For these reasons, in neurophysiology, many studies have emphasized the significance of the feedforward control ability of human. Virtual trajectory control hypothesis and internal model hypothesis have been referred to explain stable and robust motion generating ability of human under feedforward control. Inspired by the achievement of the previous studies, a hypothesis that joint stiffness can be utilized to compensate inverse dynamics model uncertainty is proposed. To verify this hypothesis, a robot which can control joint stiffness is developed. From the experimental results, the developed robot shows stable and accurate motion tracking performance without any sensors and precise inverse dynamics model. These results indicate that the concept of the developed variable stiffness actuator can be applied to the robotics field for feedforward application, and support the hypothesis that human utilize joint stiffness to adapt to uncertain environment.한국과학기술원 :기계공학과
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