720 Development of an Artificial Joint Mechanism Controlled by Air Pressure

To precisely achieve a series of daily finger bending motions, a soft robotic finger corresponding to the anatomical range of each joint was designed in this study with multi-material pneumatic actuators. The actuator as a biomimetic artificial joint was developed on the basis of two composite materials of different shear modules, and the pneumatic bellows as expansion parts was restricted by frame that made from polydimethylsiloxane (PDMS). A simplified mathematical model was used for the bending mechanism description and provides guidance for the multi-material pneumatic actuator fabrication (e.g., stiffness and thickness) and structural design (e.g., cross length and chamber radius), as well as the control parameter optimization (e.g., the air pressure supply). An actuation pressure of over 70 kPa is required by the developed soft robotic finger to provide a full motion range (MCP = 36°, PIP = 114°, and DIP = 75°) for finger action mimicking. In conclusion, a multi-material pneumatic actuator was designed and developed for soft robotic finger application and theoretically and experimentally demonstrated its feasibility in finger action mimicking. This study explored the mechanical properties of the actuator and could provide evidence-based technical parameters for pneumatic robotic finger design and precise control of its dynamic air pressure dosages in mimicking actions. Thereby, the conclusion was supported by the results theoretically and experimentally, which also aligns with our aim to design and develop a multi-material pneumatic actuator as a biomimetic artificial joint for soft robotic finger application.

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Anchorage of Wrist Joint Prostheses to Bone Using the Osseointegration Principle

Journal of Hand Surgery (European Volume) ◽

10.1016/s0266-7681(97)80026-5 ◽

1997 ◽

Vol 22 (1) ◽

pp. 84-89 ◽

Cited By ~ 9

Author(s):

G. LUNDBORG ◽

P. I. BRÅNEMARK

Keyword(s):

Wrist Joint ◽

Clinical Results ◽

Joint Arthroplasty ◽

Artificial Joint ◽

Range Of Movement ◽

Titanium Screws ◽

Joint Mechanism ◽

Joint Prostheses ◽

Observation Period

Five patients with rheumatoid arthritis (age 28–60 years) underwent wrist joint arthroplasty with individually designed artificial joint mechanisms, anchored to bone using the osseointegration principle. We report on the result from a 4 to 6.5 year follow-up with special emphasis on the fixation of the prosthesis to bone. There was no bone resorption or loosening of screws. Osseointegration of the titanium screws occurred in all cases and persisted throughout the observation period, although scattered lytic zones could sometimes be seen around the screws. The clinical results were satisfactory with pain relief and maintenance of a functional range of movement. The principle has prospects for fixation of a wrist joint mechanism to bone, although the presently used joint mechanism requires further refinement.

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Sliding Filament Joint Mechanism: Biomimetic Artificial Joint Mechanism for Artificial Skeletal Muscles

Journal of Mechanisms and Robotics ◽

10.1115/1.4042349 ◽

2019 ◽

Vol 11 (2) ◽

Cited By ~ 2

Author(s):

Kyeong Ho Cho ◽

Ho Sang Jung ◽

Sang Yul Yang ◽

Youngeun Kim ◽

Hugo Rodrigue ◽

...

Keyword(s):

Skeletal Muscles ◽

Linear Displacement ◽

Joint Control ◽

Artificial Joint ◽

Body Parts ◽

Restoring Force ◽

Artificial Joints ◽

Living Body ◽

Joint Mechanism ◽

Control Principle

Soft linear actuators (SLAs) make linear displacement by shrinkage and relaxation like skeletal muscles, so they can be called as artificial skeletal muscles (ASMs). They deform their body to create displacement. However, the restoring force generated by the deformation of their soft body reduces the force available from the SLA. This actuation structure is a critical drawback in the application of SLAs. In a living body, skeletal muscle is the main actuator to make movement. In order to make meaningful movements, skeletal muscles of a living body require bones and joints. Thus, as well as ASMs, artificial joints are surely required for developing robotic applications such as robotic prosthetics and bionic body parts. This paper introduces a biomimetic artificial joint mechanism that can improve the drawback of SLA. The basic performance and usefulness of the joint mechanism was confirmed by using shape-memory-alloy actuators (called SMA in general). In addition, the joint control strategy of the joint mechanism by adopting the joint control principle of a living body was proposed and its performance was experimentally validated.

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Signal Interpretation Considerations When Estimating Subglottal Pressure From Oral Air Pressure

Journal of Speech Language and Hearing Research ◽

10.1044/2018_jslhr-s-17-0432 ◽

2019 ◽

Vol 62 (5) ◽

pp. 1326-1337 ◽

Cited By ~ 2

Author(s):

Brittany L. Perrine ◽

Ronald C. Scherer ◽

Jason A. Whitfield

Keyword(s):

Standard Condition ◽

Word Production ◽

Air Pressure ◽

Pressure Waveform ◽

Pressure Measurements ◽

Air Leak ◽

Pressure Signal ◽

Adult Participants ◽

Syllable Repetition ◽

Subglottal Pressure

Purpose Oral air pressure measurements during lip occlusion for /pVpV/ syllable strings are used to estimate subglottal pressure during the vowel. Accuracy of this method relies on smoothly produced syllable repetitions. The purpose of this study was to investigate the oral air pressure waveform during the /p/ lip occlusions and propose physiological explanations for nonflat shapes. Method Ten adult participants were trained to produce the “standard condition” and were instructed to produce nonstandard tasks. Results from 8 participants are included. The standard condition required participants to produce /pːiːpːiː.../ syllables smoothly at approximately 1.5 syllables/s. The nonstandard tasks included an air leak between the lips, faster syllable repetition rates, an initial voiced consonant, and 2-syllable word productions. Results Eleven oral air pressure waveform shapes were identified during the lip occlusions, and plausible physiological explanations for each shape are provided based on the tasks in which they occurred. Training the use of the standard condition, the initial voice consonant condition, and the 2-syllable word production increased the likelihood of rectangular oral air pressure waveform shapes. Increasing the rate beyond 1.5 syllables/s improved the probability of producing rectangular oral air pressure signal shapes in some participants. Conclusions Visual and verbal feedback improved the likelihood of producing rectangular oral air pressure signal shapes. The physiological explanations of variations in the oral air pressure waveform shape may provide direction to the clinician or researcher when providing feedback to increase the accuracy of estimating subglottal pressure from oral air pressure.

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