scholarly journals Preliminary findings of finger independency and visual force control in children with DCD

2015 ◽  
Vol 9 (2) ◽  
Author(s):  
Marcio Alves de Oliveira
Keyword(s):  
Performance Measures ◽  
Force Control ◽  
Degrees Of Freedom ◽  
Motor Task ◽  
Finger Force ◽  
Everyday Activities ◽  
Force Sharing ◽  
Finger Forces ◽  
Sharing Patterns ◽  
Maximum Voluntary Force

To examine finger force independency, maximum voluntary force (MVF), force enslaving (FE) and force sharing (FS) values were computed. To analyze the ability of children with DCD to visually control their finger forces, the following performance measures were calculated: rate of force change, initial overshoot, coefficient of variation (CV), root mean square error (RMSe), and inter-trial variability. The results from the MVF task showed that children with DCD as compared with TD children (a) produced similar levels of maximum finger force; (b) demonstrated less finger independency;(c) had similar finger-force sharing patterns. In addition, from the VFC task we found (d) larger performance errors in children with DCD;(e) and lower inter-trial consistency as compared to their TD peers.Our preliminary findings suggest that the impairments in manipulative skills often observed in children with DCD during everyday activities may be related to deficits in finger independency.Additionally we found that children with DCD do not have difficulties in reducing the number of joint/muscle-level degrees of freedom in order to achieve a common motor task.

scholarly journals Preliminary findings of finger independency and visual force control in children with DCD

2015 ◽  
Vol 9 (2) ◽  
Author(s):  
Marcio Alves de Oliveira
Keyword(s):  
Force Control ◽  
Degrees Of Freedom ◽  
Motor Task ◽  
Force Production ◽  
Typically Developing ◽  
Finger Force ◽  
Force Sharing ◽  
Finger Forces ◽  
Sharing Patterns ◽  
Maximum Voluntary Force

<p>Finger independency and visual force control were studied in children with DCD. Five children, 9 to10 years of age, diagnosed with DCD and five age-matched typically developing children were asked to perform two isometric tasks, maximum voluntary force production (MVF) and visual force control (VFC), in seven different finger conditions [Index (I), Middle (M), Ring (R), Little (L) IM, IMR, and IMRL]. For the VFC tasks, the participants were asked to continuously control their finger forces at 20% of the MVF. To examine finger force independency, maximum voluntary force (MVF), force enslaving (FE) and force sharing (FS) values were computed. To analyze the ability of children with DCD to visually control their finger forces, the following performance measures were calculated: rate of force change, initial overshoot, coefficient of variation (CV), root mean square error (RMSe), and inter-trial variability. The results from the MVF task showed that children with DCD as compared with TD children (a) produced similar levels of maximum finger force; (b) demonstrated less finger independency; (c) had similar finger-force sharing patterns. In addition, from the VFC task we found (d) larger performance errors in children with DCD; (e) and lower inter-trial consistency as compared to their TD peers. Our preliminary findings suggest that the impairments in manipulative skills often observed in children with DCD during everyday activities may be related to deficits in finger independency. Additionally we found that children with DCD do not have difficulties in reducing the number of joint/muscle-level degrees of freedom in order to achieve a common motor task.</p>

The beneficial effects of subthalamic nucleus stimulation on manipulative finger force control in Parkinson's disease

2005 ◽  
Vol 193 (2) ◽  
pp. 427-436 ◽  
Author(s):  
Dennis A. Nowak ◽  
Helge Topka ◽  
Stephen Tisch ◽  
Marwan Hariz ◽  
Patricia Limousin ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Subthalamic Nucleus ◽  
Force Control ◽  
Finger Force ◽  
Beneficial Effects ◽  
Subthalamic Nucleus Stimulation

A new representation for a robot grasping quality measure

Robotica ◽  
1995 ◽  
Vol 13 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Venugopal K. Varma ◽  
Uri Tasch
Keyword(s):  
Objective Function ◽  
Material Properties ◽  
Graphical Representation ◽  
Contact Forces ◽  
Geometric Constraints ◽  
Objective Functions ◽  
Finger Force ◽  
Finger Forces ◽  
Robot Grasping ◽  
Selection Of

SummaryWhen an object is held by a multi-fingered hand, the values of the contact forces can be multivalued. An objective function, when used in conjunction with the frictional and geometric constraints of the grasp, can however, give a unique set of finger force values. The selection of the objective function in determining the finger forces is dependent on the type of grasp required, the material properties of the object, and the limitations of the röbot fingers. In this paper several optimization functions are studied and their merits highlighted. The paper introduces a graphical representation of the finger force values and the objective functions that enable one to select and compare various grasping configurations. The impending motion of the object at different torque and finger force values are determined by observing the normalized coefficient of friction plots.

Finger force sharing during an adapted power grip task

2011 ◽  
Vol 504 (3) ◽  
pp. 290-294 ◽  
Author(s):  
Laurent Vigouroux ◽  
Jérémy Rossi ◽  
Matthieu Foissac ◽  
Laurent Grélot ◽  
Eric Berton
Keyword(s):  
Finger Force ◽  
Power Grip ◽  
Force Sharing

Training Effects on Response Strategies in a Perceptual Motor Task

1985 ◽  
Vol 29 (8) ◽  
pp. 755-758
Author(s):  
Jani Gabriel Byrne ◽  
Nancy S. Anderson
Keyword(s):  
Individual Differences ◽  
Performance Measures ◽  
Dual Task ◽  
Response Pattern ◽  
Motor Task ◽  
Response Strategy ◽  
Time Sharing ◽  
Close Inspection ◽  
Response Strategies ◽  
Early Performance

This study examined the influence of training on individual differences in time-sharing response strategies for a dual-task. Using early performance measures in a dual-task, subjects were classified on Day 1 as performing in either a simultaneous, alternating, or massed fashion. On Day 2, subjects received training instructions to either upgrade or maintain their particular response strategy. The results indicated that training was successful in the majority of the cases. Close inspection of performance revealed that subjects who were not able to achieve simultaneity had learned the dual-task response pattern, but were responding too slowly.

Pneumatically Driven Prehension Orthosis with Force Control Function

2013 ◽  
Vol 25 (6) ◽  
pp. 973-982 ◽  
Author(s):  
Shunji Moromugi ◽  
◽  
Takayuki Tanaka ◽  
Toshio Higashi ◽  
Maria Q. Feng ◽  
...  
Keyword(s):  
Force Control ◽  
Muscle Activity ◽  
Control Function ◽  
Spinal Cord Injury Patient ◽  
Target Object ◽  
Cervical Cord ◽  
Finger Force ◽  
Cord Injury ◽  
Injury Patient ◽  
User Friendly

A prehension orthosis with a pneumatic actuator has been developed to compensate for the disability of cervical cord injury patients and support their daily activities. One major feature of this orthosis is that the user can continually pinch or hold a target object using a finely adjusted finger force. The movement and force applied to the fingers can be controlled by continuous instructional signals fromthe user through the activity of a command muscle, which is selected from among the muscles without functional impairment in the user’s body. The level of muscle activity can be obtained by using an original sensor that detects the hardness of the target muscle through contact with the skin. The level of muscle activity can be estimated by the hardness information of the muscle. This sensor is easily fixed to a user’s body by using an elastic belt and even works over clothing. Therefore, the user can wear the system very easily. This feature allows the system to be very user friendly. Users can handle fragile objects such as an egg or sculpted-glass by using this prehension orthosis because of its finger force control function. Excellent dexterity in the finger force control has been demonstrated through evaluation tests conducted with various subjects, including a spinal cord injury patient.

Analysis of Hand-Arm Coordinate Motion on Constraint Tasks

1991 ◽  
Vol 3 (6) ◽  
pp. 497-505
Author(s):  
Shigeki Sugano ◽  
◽  
Hideyo Namimoto ◽  
Ichiro Kato
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Degrees Of Freedom ◽  
Control Mechanism ◽  
Human Motion ◽  
Degree Of Freedom ◽  
Human Hand ◽  
Human Motion Analysis ◽  
Manipulator Control ◽  
Arm Coordination

This research was conducted to study the control strategy of manipulator based on clarifying the force control mechanism of the human hand-arm by analyzing human constraint tasks with respect to biomechanism. In this paper; we describe an investigation of hand-arm function share. In addition, we apply hand-arm coordination to manipulator control using experimental results of analyzing the human tasks of moving bead balls on a shaft, which is an example of a constraint task with one degree of freedom (d.o.f.). In the human motion analysis, 6 axes of force on the task object are measured and compared in the case of constraining the hands degree of freedom and making hand free as well as in the case of with or without forced displacement along the translational direction during motion. As a result, we found that human work was performed smoothly through absorption of rotational force using hand d.o.f. and translational force using arm d.o.f. Also, it was found that there are the direction of motion and the posture easily absorbable translational force. Finally, we propose to apply the human hand-arm coordination compliance control strategy setting translational compliance by arms and rotational compliance by hands, to manipulator with more than 7 degrees of freedom. Thus, the setting of optional compliance applicable to circumstance and the resulting force control due to this become possible.

Optimization-based posture prediction for human upper body

Robotica ◽  
2009 ◽  
Vol 27 (4) ◽  
pp. 607-620 ◽  
Author(s):  
Zan Mi ◽  
Jingzhou (James) Yang ◽  
Karim Abdel-Malek
Keyword(s):  
Performance Measures ◽  
Degrees Of Freedom ◽  
Human Performance ◽  
Computational Algorithm ◽  
Performance Measure ◽  
Upper Body ◽  
Cost Functions ◽  
Posture Prediction ◽  
Joint Limits ◽  
Digital Human

SUMMARYA general methodology and associated computational algorithm for predicting postures of the digital human upper body is presented. The basic plot for this effort is an optimization-based approach, where we believe that different human performance measures govern different tasks. The underlying problem is characterized by the calculation (or prediction) of the human performance measure in such a way as to accomplish a specified task. In this work, we have not limited the number of degrees of freedom associated with the model. Each task has been defined by a number of human performance measures that are mathematically represented by cost functions that evaluate to a real number. Cost functions are then optimized, i.e., minimized or maximized, subject to a number of constraints, including joint limits. The formulation is demonstrated and validated. We present this computational formulation as a broadly applicable algorithm for predicting postures using one or more human performance measures.

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