Intention-Based EMG Control for Powered Exoskeletons Lenzi, Tommaso; De Rossi, Stefano Marco Maria; Vitiello, Nicola ...
IEEE transactions on biomedical engineering,
08/2012, Letnik:
59, Številka:
8
Journal Article
Recenzirano
Electromyographical (EMG) signals have been frequently used to estimate human muscular torques. In the field of human-assistive robotics, these methods provide valuable information to provide ...effectively support to the user. However, their usability is strongly limited by the necessity of complex user-dependent and session-dependent calibration procedures, which confine their use to the laboratory environment. Nonetheless, an accurate estimate of muscle torque could be unnecessary to provide effective movement assistance to users. The natural ability of human central nervous system of adapting to external disturbances could compensate for a lower accuracy of the torque provided by the robot and maintain the movement accuracy unaltered, while the effort is reduced. In order to explore this possibility, in this paper we study the reaction of ten healthy subjects to the assistance provided through a proportional EMG control applied by an elbow powered exoskeleton. This system gives only a rough estimate of the user muscular torque but does not require any specific calibration. Experimental results clearly show that subjects adapt almost instantaneously to the assistance provided by the robot and can reduce their effort while keeping full control of the movement under different dynamic conditions (i.e., no alterations of movement accuracy are observed).
Highlights • Bovine teeth can be used as a substitute of human teeth on bond strength studies. • Both substrates—enamel and dentin of bovine teeth seems to be similar to human ones considering bond ...strength values. • Bovine primary teeth should be used carefully as a substitute of human primary teeth considering the number of studies comparing these substrates.
This paper presents the design and experimental testing of the robotic elbow exoskeleton NEUROBOTICS Elbow Exoskeleton (NEUROExos). The design of NEUROExos focused on three solutions that enable its ...use for poststroke physical rehabilitation. First, double-shelled links allow an ergonomic physical human-robot interface and, consequently, a comfortable interaction. Second, a four-degree-of-freedom passive mechanism, embedded in the link, allows the user's elbow and robot axes to be constantly aligned during movement. The robot axis can passively rotate on the frontal and horizontal planes 30° and 40°, respectively, and translate on the horizontal plane 30 mm. Finally, a variable impedance antagonistic actuation system allows NEUROExos to be controlled with two alternative strategies: independent control of the joint position and stiffness, for robot-in-charge rehabilitation mode, and near-zero impedance torque control, for patient-in-charge rehabilitation mode. In robot-in-charge mode, the passive joint stiffness can be changed in the range of 24-56 N·m/rad. In patient-in-charge mode, NEUROExos output impedance ranges from 1 N·m/rad, for 0.3 Hz motion, to 10 N·m/rad, for 3.2 Hz motion.
The field of wearable robotics is gaining momentum thanks to its potential application in rehabilitation engineering, assistive robotics, and power augmentation. These devices are designed to be used ...in direct contact with the user to aid with movement or increase the power of specific skeletal joints. The design of the so-called physical human-robot interface is critical, since it determines not only the efficacy of the robot but the kinematic compatibility of the device with the human skeleton and the degree of adaptation to different anthropometries as well. Failing to deal with these problems causes misalignments between the robot and the user joint. Axes misalignment leads to the impossibility of controlling the torque effectively transmitted to the user joint and causes undesired loading forces on articulations and soft tissues. In this paper, we propose a general analytical method for the design of exoskeletons able to assist human joints without being subjected to misalignment effects. This method is based on a kinetostatic analysis of a coupled mechanism (robot-human skeleton) and can be applied in the design of self-aligning mechanisms. The method is exemplified in the design of an assistive robotic chain for a two-degree-of-freedom (DOF) human articulation.
Purpose
To investigate the effect of different root canal filling materials on the change of failure of the endodontic treatment of necrotic primary teeth
.
Methods
A literature search was carried ...out in PubMed/MEDLINE, CENTRAL, Scopus databases, and grey literature up to July 2022 selecting randomised clinical trials related to research question. Two reviewers independently selected the studies, extracted the data, and assessed the bias risk. Root canal filling materials were grouped according to the main component iodoform (IOD), calcium hydroxide (CAOH), zinc oxide (ZO) or mix (IOD
plus
CAOH
plus
ZO) pastes. Pairwise and network meta-analyses using the mixed treatment comparisons method were performed to compare the number of events (failure) among treatments. Odds ratio and 95% confidence intervals (CI) for calculated. Post-probabilities among treatments were also calculated and interpreted.
Results
From 1186 potentially relevant studies, 17 were selected for full-text analysis, and 7 were included in the meta-analysis, totalizing 263 teeth. In the direct evidence, ZO pastes resulted in a higher chance of failure than IOD pastes (OR 7.07 95% CI 1.02, 62.59). In the indirect evidence, there was no difference between the materials. The IOD pastes presented a high probability (81%) of being the treatment associated to lowest number of failures among all treatments. The CAOH pastes presented the highest probability of being the worst option. Studies showed high bias risk.
Conclusion
There is currently no scientific evidence of the superiority of any one root canal filling material for endodontic treatment of necrotic primary teeth.
Purpose
This in vitro study evaluated the microshear bond strength (μSBS) of a universal adhesive after silver diammine fluoride (SDF) application at different concentrations on carious dentinal ...lesions in primary teeth.
Methods
Flat dentin carious-induced surfaces from 40 primary molars were randomly assigned to four experimental groups: without SDF treatment (control), 12% SDF, 30% SDF, or 38% SDF application. After 14 days of storage in artificial saliva at 37 °C, a universal adhesive system (Scotchbond Universal, 3 M ESPE) was applied in the etch-and-rinse mode and resin composite cylinders were built (0.72 mm
2
). After 24 h of water storage, the μSBS test was performed and the failure mode was determined. Data were analysed using one-way ANOVA and Tukey’s post hoc tests (
α
= 0.05).
Results
The application of 38% SDF resulted in higher μSBS mean than control and use of 12% SDF (
p
= 0.006). No significant differences were observed among control, 12% SDF, and 30% SDF. All specimens tested showed adhesive/mixed failure.
Conclusion
The use of SDF does not jeopardise the bonding of a universal adhesive applied in the etch-and-rinse mode to carious dentinal lesions in primary teeth, irrespective of the product concentration
.
The purpose of this study was to evaluate the influence of water storage on bond strength of multimode adhesive systems to artificially induced caries-affected dentin. One hundred twelve sound bovine ...incisors were randomly assigned to 16 groups (n=7) according to the dentin condition (sound; SND, artificially induced caries-affected dentin; CAD, cariogenic challenge by pH cycling for 14 days); the adhesive system (SU, Scotchbond Universal Adhesive; AB, All-Bond Universal; PB, Prime & Bond Elect; SB, Adper Single Bond 2; and CS, Clearfil SE Bond), and the etching strategy (etch-and-rinse and self-etch). All adhesive systems were applied under manufacturer's instructions to flat dentin surfaces, and a composite block was built up on each dentin surface. After 24 hours of water storage, the specimens were sectioned into stick-shaped specimens (0.8 mm
) and submitted to a microtensile test immediately (24 hours) or after six months of water storage. Bond strength data (MPa) were analyzed using three-way repeated-measures analysis of variance and post hoc Tukey test (α=5%), considering each substrate separately (SND and CAD). The etching strategy did not influence the bond strength of multimode adhesives, irrespective of the dentin condition. Water storage only reduced significantly the bond strength to CAD. The degradation of bond strength due to water storage was more pronounced in CAD, regardless of the etching strategy.
Estimation of the temporal derivatives of a noisy position signal is a ubiquitous problem in industrial and robotics engineering. Here, we propose a new approach to get velocity and acceleration ...estimates of cyclical/periodic signals near to steady-state regime, by using adaptive oscillators. Our method combines the advantages of introducing no delay, and filtering out the high-frequency noise. We expect this method to be useful in control applications requiring undelayed but smooth estimates of velocity and acceleration (e.g., velocity control and inverse dynamics) of quasi-periodic tasks (e.g., active vibration compensation, robot locomotion, and lower-limb movement assistance).
PURPOSETo describe the prevalence and the variables associated with TDIs in schoolchildren aged 8 to 14 years in Estância Velha city in southern Brazil, placing emphasis on molar incisor ...hypomineralization.METHODSStudents enrolled in public schools of a medium-sized city in the southern Brazil were selected using cluster random sampling. Clinical examinations assessed molar incisor hypomineralization-MIH (European Academy of Pediatric Dentistry criteria), dental caries (DMFT index), and TDIs (O'Brien's criteria). Socioeconomic and demographic variables were assessed using a standardized questionnaire. Prevalence ratios were estimated using Poisson regression (p < 0.05).RESULTS513 students (54.8% female), with a mean age of 11.6 (± 1.9) years, participated in the study. The prevalence of TDIs was 11.3%, with enamel fracture representing 90.4%. The high prevalence of traumatic dental injuries was associated with MIH (PR: 2.22 CI: 1.27; 3.87; p < 0.01) and overjet > 3 mm (PR: 2.03 CI 1.19; 3.45; p < 0.01).CONCLUSIONThe sample of schoolchildren from southern Brazil had a low prevalence of traumatic dental injuries. Molar incisor hypomineralization and increased overjet were associated with the higher prevalence of traumatic dental injuries.
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