Characterizing the Human Wrist for Improved Haptic Interaction

2003 ◽  
Author(s):  
Katherine J. Kuchenbecker ◽  
June Gyu Park ◽  
Gu¨nter Niemeyer
Keyword(s):  
Grip Force ◽  
Force Measurement ◽  
Wrist Joint ◽  
Calibration Procedure ◽  
Order System ◽  
Response Characteristics ◽  
Haptic Displays ◽  
Positive Linear Correlation ◽  
Improved Performance ◽  
Sense Of Touch

Haptic displays provide the user with a sense of touch in both simulation of virtual environments and teleoperation of remote robots. The instantaneous impedance of the user’s hand affects this force interaction, changing the transients experienced during activities such as exploratory tapping. This research characterizes the behavior of the human wrist joint while holding a stylus in a three-fingered grasp. Nonparametric identification methods, evaluating frequency-and time-responses, support a second-order system model. Further analysis shows a positive linear correlation between grip force and wrist impedance for all subjects, though each individual’s trend is unique. These findings suggest that a quick calibration procedure and a realtime grip force measurement could enable a haptic display to predict user response characteristics throughout an interaction. Such knowledge would enable haptic control algorithms to adapt continuously to the user’s instantaneous state for improved performance.

scholarly journals Is the grip force measurement suitable for assessing overall strength regardless of age and gender?

Measurement ◽  
2021 ◽  
Vol 176 ◽  
pp. 109093
Author(s):  
Danuta Roman-Liu ◽  
Tomasz Tokarski ◽  
Joanna Mazur-Różycka
Keyword(s):  
Grip Force ◽  
Force Measurement ◽  
Age And Gender ◽  
And Gender

scholarly journals Model Calibration for a Rigid Hexapod-Based End-Effector with Integrated Force Sensors

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3537
Author(s):  
Christian Friedrich ◽  
Steffen Ihlenfeldt
Keyword(s):  
Parameter Identification ◽  
Degrees Of Freedom ◽  
Force Measurement ◽  
Experimental Studies ◽  
Measurement Model ◽  
Calibration Procedure ◽  
Force Sensors ◽  
End Effector ◽  
Measurement Models ◽  
Fast Procedure

Integrated single-axis force sensors allow an accurate and cost-efficient force measurement in 6 degrees of freedom for hexapod structures and kinematics. Depending on the sensor placement, the measurement is affected by internal forces that need to be compensated for by a measurement model. Since the parameters of the model can change during machine usage, a fast and easy calibration procedure is requested. This work studies parameter identification procedures for force measurement models on the example of a rigid hexapod-based end-effector. First, measurement and identification models are presented and parameter sensitivities are analysed. Next, two excitation strategies are applied and discussed: identification from quasi-static poses and identification from accelerated continuous trajectories. Both poses and trajectories are optimized by different criteria and evaluated in comparison. Finally, the procedures are validated by experimental studies with reference payloads. In conclusion, both strategies allow accurate parameter identification within a fast procedure in an operational machine state.

Robust Nonlinear Control of a Novel Indexing Valve Plate Pump: Simulation Studies

2002 ◽  
Vol 124 (4) ◽  
pp. 613-616 ◽  
Author(s):  
X. Zhang ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Pressure Control ◽  
Plate Motion ◽  
Nonlinear Simulation ◽  
Response Characteristics ◽  
Model Free ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Robust Adaptive ◽  
Improved Performance

A robust adaptive pressure control strategy is proposed for a novel indexing variable-displacement pump. In the proposed approach, parametric uncertainties and unmodeled dynamics are identified to the extent possible using a model free learning network and used to decouple the dynamics using physical insights derived from careful reduced order modeling. The swash plate motion control is then carefully designed to provide the desired pressure response characteristics showing improved performance with learning. The proposed control framework and designs are validated using a detailed nonlinear simulation model.

scholarly journals Evaluation of thin, flexible sensors for time-resolved grip force measurement

2007 ◽  
Vol 221 (12) ◽  
pp. 1687-1699 ◽  
Author(s):  
E R Komi ◽  
J R Roberts ◽  
S J Rothberg
Keyword(s):  
Shear Force ◽  
Grip Force ◽  
Force Measurement ◽  
Real Life ◽  
Force Sensor ◽  
Ease Of Use ◽  
Time Resolved ◽  
Flexible Sensors ◽  
Sensor Performance ◽  
Dynamic Accuracy

Three types of thin, flexible force sensor were studied under a variety of loading conditions to determine their suitability for measuring grip force. Static accuracy, hysteresis, repeatability, and drift errors were established, the effects of shear force and surface curvature were considered, and dynamic accuracy and drift were measured. Novel tests were developed to consider dynamic accuracy and sensitivity to shear loadings. Additionally, three sensors were evaluated in a real-life gripping scenario, measuring grip force during a golf shot. Comments are made on sensor performance, ease of use, and durability.

Low Order Vibration Models for Tracked Vehicles

1999 ◽  
Author(s):  
C. Scholar ◽  
N. C. Perkins ◽  
Z.-D. Ma
Keyword(s):  
Large Degree ◽  
Element Model ◽  
Forced Response ◽  
Minimum Size ◽  
Order System ◽  
Continuum Approximation ◽  
Translation Speed ◽  
Response Characteristics ◽  
Multi Body ◽  
Low Order

Abstract A vehicle track model is developed with the objective of providing new capabilities in modeling track vibration response. Understanding track vibration is essential to evaluating the durability of track components, the vibration energy transmitted to the vehicle, and the acoustic emission from the vehicle. A new element model is derived herein that represents a track span as a continuous elastic member with distributed inertia. This model captures the effects of static track sag. static and dynamic track tension, track translation speed, and the coupling of longitudinal and transverse track vibration. Results from a companion experimental study on a section of track support the use of this continuum approximation. The track element model is extended to describe an entire track circuit for an example military vehicle. An eigenanalysis of this circuit model leads to the system vibration modes that are subsequently employed in a low-order model for forced response. The forced response characteristics resulting from two major excitation sources, roadarm motion and polygonal action, are described. The modal content of the track response is then examined to determine the minimum size model required to describe track vibration. It is concluded that low-order system models may be developed as efficient alternatives to established large degree-of-freedom multi-body track models.

Handle Shape Affects the Grip Force Distribution and the Muscle Loadings During Power Grip Tasks

2015 ◽  
Vol 31 (6) ◽  
pp. 430-438 ◽  
Author(s):  
Jérémy Rossi ◽  
Benjamin Goislard De Monsabert ◽  
Eric Berton ◽  
Laurent Vigouroux
Keyword(s):  
Grip Force ◽  
Wrist Joint ◽  
Force Sensor ◽  
Force Distribution ◽  
Muscle Coordination ◽  
Muscle Forces ◽  
Power Grip ◽  
Coordination Strategies ◽  
Hand Model ◽  
Kinematic Measurement

The objectives of this study were to investigate the effect of handle shape on the grip force distribution in the hand and on the muscle forces during maximal power grip tasks. Eleven subjects maximally grasped 3 handles with different external shapes (circular, elliptic, and double-frustum). A handle dynamometer, equipped with both a force sensor and a pressure map, was used to record the forces exerted at the hand/handle interface. The finger and wrist joint postures were also computed from synchronized kinematic measurement. These processed data were then used as input of a biomechanical hand model to estimate muscle forces. The results showed that handle shape influences the maximal grip force, the grip force distribution, and the finger joint postures. Particularly, we observed that the elliptical shape resulted in a 6.6% lower maximal grip force compared with the circular and double-frustum handle. Concomitantly, the estimated muscle forces also varied significantly according to the handle shape, with up to 48% differences for the flexor digitorum superficialis muscle for example. Interestingly, different muscle coordination strategies were observed depending on the handle shape, therefore suggesting a potential influence of these geometrical characteristics on pathological risks such as tendonitis.

scholarly journals Poststimulus response characteristics of the human cone flicker electroretinogram

2013 ◽  
Vol 30 (4) ◽  
pp. 147-152
Author(s):  
SOWJANYA GOWRISANKARAN ◽  
J. JASON McANANY ◽  
KENNETH R. ALEXANDER
Keyword(s):  
Ganglion Cells ◽  
Stimulus Frequency ◽  
Second Order ◽  
Bipolar Cells ◽  
Order System ◽  
Resonant System ◽  
Full Field ◽  
Response Characteristics ◽  
Electrophysiological Recordings ◽  
Timing Properties

AbstractAt certain temporal frequencies, the human cone flicker electroretinogram (ERG) contains multiple additional responses following the termination of a flicker train. The purpose of this study was to determine whether these poststimulus responses are a continuing response to the terminated flicker train or represent the oscillation of a resonant system. ERGs were recorded from 10 visually normal adults in response to full-field sinusoidally modulated flicker trains presented against a short-wavelength rod-saturating adapting field. The amplitude and timing properties of the poststimulus responses were evaluated within the context of a model of a second-order resonant system. At stimulus frequencies between 41.7 and 71.4 Hz, the majority of subjects showed at least three additional ERG responses following the termination of the flicker train. The interval between the poststimulus responses was approximately constant across stimulus frequency, with a mean of 14.4 ms, corresponding to a frequency of 69.4 Hz. The amplitude and timing characteristics of the poststimulus ERG responses were well described by an underdamped second-order system with a resonance frequency of 70.3 Hz. The observed poststimulus ERG responses may represent resonant oscillations of retinal ON bipolar cells, as has been proposed for electrophysiological recordings of poststimulus responses from retinal ganglion cells. However, further investigation is required to determine the types of retinal neurons involved in the generation of the poststimulus responses of the human flicker ERG.

Sign in / Sign up

Export Citation Format

Share Document