Identification of the Mechanical Impedance at the Human Finger Tip

1997 ◽  
Vol 119 (1) ◽  
pp. 109-114 ◽  
Author(s):  
A. Z. Hajian ◽  
R. D. Howe
Keyword(s):  
Linear Model ◽  
Muscle Activation ◽  
Index Finger ◽  
Damping Ratio ◽  
Mechanical Impedance ◽  
Order Linear ◽  
Human Finger ◽  
Rapid Transients ◽  
Finger Tip ◽  
Tip Mass

Rapid transients were applied to the outstretched human index finger tip, which resulted in motion primarily at the metacarpophalangeal (MCP) joint in extension and in abduction. A second-order linear model was fit to approximately 20 milliseconds of the force and displacement data to determine the effective mechanical impedance at the finger tip. Ranges of mass, damping, and stiffness parameters were estimated over a range of mean finger tip force (2–20 N for extension, 2–8 N for abduction). Effective translational finger tip mass for each subject was relatively constant for force levels greater than 6 N for extension, and constant throughout the abduction trials. Stiffness increased linearly with muscle activation. The estimated damping ratio for extension trials was about 1.7 times the ratio for abduction.

scholarly journals Interpretation of the Directional Properties of Voluntarily Modulated Human Ankle Mechanical Impedance

2010 ◽  
Author(s):  
Patrick Ho ◽  
Hyunglae Lee ◽  
Mohammad A. Rastgaar ◽  
Hermano Igo Krebs ◽  
Neville Hogan
Keyword(s):  
Muscle Activation ◽  
Mechanical Impedance ◽  
In Vivo Studies ◽  
General Representation ◽  
Quantitative Characterization ◽  
Ankle Impedance ◽  
Human Ankle ◽  
Electromyographic Recording

This article presents the results of two in-vivo studies providing measurements of human static ankle mechanical impedance. Accurate measurements of ankle impedance when muscles were voluntarily activated were obtained using a therapeutic robot, Anklebot, and an electromyographic recording system. Important features of ankle impedance, and their variation with muscle activity, are discussed, including magnitude, symmetry and directions of minimum and maximum impedance. Voluntary muscle activation has a significant impact on ankle impedance, increasing it by up to a factor of three in our experiments. Furthermore, significant asymmetries and deviations from a linear two-spring model are present in many subjects, indicating that ankle impedance has a complex and individually idiosyncratic structure. We propose the use of Fourier series as a general representation, providing both insight and a precise quantitative characterization of human static ankle impedance.

Design of Workspace of Human Fingers and Computer Keyboard Operation

2014 ◽  
Vol 484-485 ◽  
pp. 1118-1125
Author(s):  
Rao Shun
Keyword(s):  
Degrees Of Freedom ◽  
Index Finger ◽  
Operation Mode ◽  
Penalty Function Method ◽  
Three Dimension ◽  
Mechanism Model ◽  
Reachable Workspace ◽  
Human Arm ◽  
Dimension Space ◽  
Human Finger

There are more and more complex tools and machinery that need be operated by human fingers in our modem industrial environment. Such as computer keyboards, screwdriver, handle wrench, button and switch. All of those should be designed to work effectively and safely with the operators for whom they were designed. At first, ergonomic consideration in design is reachable; this means the operators fingertip must be able to reach the operating component. This is generally no question because human arm has much more degrees of freedom required to position his arms, hands and fingers in the three-dimension space. However, some times we need the finger operate with a fixed wrist. For example in the case in the typing, the reachable workspace of the finger must take into account in such situation.Finger contacting is the most familiar operation mode of the man-machine system, and the index finger takes on the primary operation tasks. From viewpoint of ergonomic engineering, the operation component should be placed within the workspace of the fingertip to reduced or eliminate the movement of palm and arm should to the greatest extent during finger manipulation. Therefore the research of the workspace of ginger is significant to the ergonomic design of the operation device. In this paper, the reachable workspace and workspace under direction restrain of contacting for the index finger are determined using serial mechanism model and the Penalty Function Method based on geometric measurement of human body. The optimal operating position and orientation of human finger is analyzed.

scholarly journals Research on finger movement sensing performance of conductive gloves

2019 ◽  
Vol 14 ◽  
pp. 155892501988762 ◽  
Author(s):  
Xiaoxue Han ◽  
Xuhong Miao ◽  
Xi Chen ◽  
Gaoming Jiang ◽  
Li Niu
Keyword(s):  
Index Finger ◽  
Dynamic Test ◽  
Rehabilitation Medicine ◽  
Proximal Interphalangeal Joint ◽  
Knitted Fabric ◽  
Resistance Change ◽  
Flexible Sensors ◽  
Finger Motion ◽  
Human Finger ◽  
Resistance Data

Knitted flexible sensors are sensors based on the loop structure of knitted fabric, which are soft and close-fitting. Monitoring finger motion can obtain useful information for some applications such as rehabilitation medicine, sports bionics, or human–computer interaction. In this paper, a conductive glove was knitted by SHIMA Seiki SWG 061N-15G computerized flat knitting machine. One experimenter wore it to measure motions data of index finger. The glove has a conductive intarsia area knitted by silver-nylon filaments. The experimenter performed static and dynamic test of hand posture, respectively, then observed the effect of figure bending characteristics on the glove resistance data. The result showed that human finger motion can be monitored successfully by the conductive glove without hard transducers, and both of the bending rate ( Br) and bending angle of the finger proximal interphalangeal joint ( Pba) affect the resistance change of the conductive area of the glove. In other words, the conductive glove has potentials to monitor and reflect human finger motions in detail.

Nonlinear Dynamic Modeling of Elastic Beam Fixed on a Moving Cart and Carrying Lumped Tip Mass Subjected to External Periodic Force

2009 ◽  
Author(s):  
Fadi A. Ghaith
Keyword(s):  
Linear Model ◽  
Equations Of Motion ◽  
Elastic Beam ◽  
Open Loop ◽  
Beam Deflection ◽  
Mode Shapes ◽  
Euler Beam ◽  
Periodic Force ◽  
Assumed Mode Method ◽  
Tip Mass

In the present work, a Bernoulli – Euler beam fixed on a moving cart and carrying lumped tip mass subjected to external periodic force is considered. Such a model could describe the motion of structures like forklift vehicles or ladder cars that carry heavy loads and military airplane wings with storage loads on their span. The nonlinear equations of motion which describe the global motion as well as the vibration motion were derived using Lagrangian approach under the inextensibility condition. In order to investigate the influence of the axial movement of the cart on the response of the system, unconstrained modal analysis has been carried out, and accurate mode shapes of the beam deflection were obtained. The assumed mode method was utilized for approximating the beam elastic deformation based on the single unconstrained mode shapes. Numerical simulation has been carried out to estimate the open-loop response of the nonlinear beam-mass-cart model as well as for the simplified linear model under the influence of the periodic excitation force. Also a comparison study between the responses of the linear and nonlinear models was established. It was shown that the maximum values of the beam tip deflection estimated from the nonlinear model are lower than the corresponding values obtained via the linear model, which reveals the importance of considering nonlinear hardening term in formulating the equations of motion for such system in order to come with more accurate and reliable model.

Stochastic Estimation of Human Ankle Mechanical Impedance in Lateral/Medial Rotation

2014 ◽  
Author(s):  
Evandro M. Ficanha ◽  
Mohammad Rastgaar
Keyword(s):  
Degrees Of Freedom ◽  
Muscle Activation ◽  
Transfer Functions ◽  
Linear Time ◽  
Mechanical Impedance ◽  
Linear Time Invariant ◽  
Ankle Impedance ◽  
Human Ankle ◽  
Medial Rotation ◽  
The Difference

This article compares stochastic estimates of human ankle mechanical impedance when ankle muscles were fully relaxed and co-contracting antagonistically. We employed Anklebot, a rehabilitation robot for the ankle to provide torque perturbations. Surface electromyography (EMG) was used to monitor muscle activation levels and these EMG signals were displayed to subjects who attempted to maintain them constant. Time histories of ankle torques and angles in the lateral/medial (LM) directions were recorded. The results also compared with the ankle impedance in inversion-eversion (IE) and dorsiflexion-plantarflexion (DP). Linear time-invariant transfer functions between the measured torques and angles were estimated for the Anklebot alone and when a human subject wore it; the difference between these functions provided an estimate of ankle mechanical impedance. High coherence was observed over a frequency range up to 30 Hz. The main effect of muscle activation was to increase the magnitude of ankle mechanical impedance in all degrees of freedom of ankle.

scholarly journals Flexion Angles of Finger Joints in Two-Finger Tip Pinching Using 3D Bone Models Constructed from X-Ray Computed Tomography (CT) Images

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Satoshi Shimawaki ◽  
Yoshiaki Nakamura ◽  
Masataka Nakabayashi ◽  
Hideharu Sugimoto
Keyword(s):  
Index Finger ◽  
Three Dimensional ◽  
High Mobility ◽  
Ct Images ◽  
Flexion Angle ◽  
Normal Hand ◽  
Distal Interphalangeal ◽  
X Ray Computed ◽  
Different Diameters ◽  
Finger Tip

The motion analysis of two-finger tip pinching using the thumb and index finger provides crucial data for designing the motion mechanism of electric prosthetic hands. The purpose of this study is to determine the joints that have high mobility during two-finger tip pinching by measuring the flexion angle of each joint. Ten Japanese men with normal hand were selected. CT images were obtained while the hands adopted the following four postures: a basic posture not pinching a cylinder, and three postures pinching wooden cylinders with different diameters (2, 10, and 30 mm). Three-dimensional bone models of the thumb and index finger were created using the CT images and used to measure the flexion angles of the joints. The flexion angles of the proximal interphalangeal and metacarpophalangeal joints of the index finger significantly decreased as the diameter of the cylinder increased. However, even when the diameter of the cylinder changed, the flexion angle of the distal interphalangeal joint of the index finger, and the flexion and rotation angles of all of the thumb joints did not change. When pinching objects of different sizes with a two-finger tip pinch, the posture of the thumb is fixed, and only the posture of the index finger changes. When designing the two-finger tip pinch motion for an electric prosthetic hand, it is sufficient to drive the joints of the index finger only.

Dynamic Observation of Sweat Glands of Human Finger Tip Using All-Optical-Fiber High-Speed Optical Coherence Tomography

2005 ◽  
Vol 44 (No. 26) ◽  
pp. L854-L856 ◽  
Author(s):  
Masato Ohmi ◽  
Kenji Nohara ◽  
Yoshihiro Ueda ◽  
Toshie Fuji ◽  
Masamitsu Haruna
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Fiber ◽  
High Speed ◽  
Sweat Glands ◽  
Optical Coherence ◽  
Dynamic Observation ◽  
All Optical ◽  
Human Finger ◽  
Finger Tip

Anthropomorphic Optimization of a Rope-Driven Prosthetic Finger

2014 ◽  
Vol 568-570 ◽  
pp. 899-903 ◽  
Author(s):  
Qun Ming Li ◽  
Yao Wen Li
Keyword(s):  
Index Finger ◽  
Optimization Method ◽  
Spring Stiffness ◽  
Joint Angles ◽  
Data Glove ◽  
Prosthetic Finger ◽  
Human Finger ◽  
The Relationship

In consideration of the importance of the prosthetic finger having the motion law of human finger. We first establish the relationship between spring stiffness and joint angles of the prosthetic finger through the analysis of the prosthetic finger kinematic. Then collect the joint angles of human index finger during natural bending by using the CyberGloveII-22 data glove. Based on this, an anthropomorphic optimization method is proposed in order to let the prosthetic dinger have the motion law of human index finger. The method in this paper can also be used to plan the trajectory of the finger.

Kinematic Study of a Soft-and-Rigid Robotic Digit for Rehabilitation and Assistive Applications

2016 ◽  
Author(s):  
Mahdi Haghshenas-Jaryani ◽  
Wei Carrigan ◽  
Muthu B. J. Wijesundara ◽  
Rita M. Patterson ◽  
Nicoleta Bugnariu ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Index Finger ◽  
Proper Function ◽  
Kinematic Parameters ◽  
Hand Rehabilitation ◽  
Molding Process ◽  
Center Of Rotation ◽  
Kinematic Study ◽  
Pip Joint ◽  
Human Finger

This paper presents the kinematic study of a pneumatically actuated soft-and-rigid robotic digit designed to be used in exoskeleton-based hand rehabilitation and assistive applications. The soft-and-rigid robotic digit is comprised of three inflatable bellow-shaped structure sections (soft sections) and four semi-rigid sections in an alternating order which correspond to the anatomy of a human finger. The forward and backward bending motions at each soft section (joint) are generated by pressure and vacuum actuation, respectively. The goal here is to investigate the compatibility of the soft robotic digit’s kinematic parameters such as range of motion, center of rotation, and lengthening at the joints with the required anatomical motion of the human finger to ensure proper function and safe interaction. The soft robotic digits were fabricated using silicone rubber materials in a compression molding process for the experimental study. The kinematic parameters of both a human and soft robotic index finger were measured using a motion capture system. The obtained results show that the robotic digit was able to provide the required range of motion: 0–90° at the metacarpophalangeal (MCP) joint, 0–100° at the proximal interphalangeal (PIP) joint, and 0–70° at the distal interphalangeal (DIP) joint. Furthermore, the data show the center of rotation of each soft section (robotic joint) was remotely coincident with that of the corresponding index finger. The lengthening of the three soft sections of the robotic digit were measured to be 7mm, 7mm, and 2mm for the MCP, PIP, and DIP, respectively. The corresponding values for the dorsal skin lengthening of a human index finger is 11mm, 15mm, and 5mm and are longer than the achieved lengthening in the robotic digit.

Sign in / Sign up

Export Citation Format

Share Document