A biomimetic reach and grasp approach for mechanical hands

2012 ◽  
Vol 60 (3) ◽  
pp. 473-486 ◽  
Author(s):  
F. Touvet ◽  
N. Daoud ◽  
J.-P. Gazeau ◽  
S. Zeghloul ◽  
M.A. Maier ◽  
...  
Keyword(s):  
Reach And Grasp ◽  
Mechanical Hands

scholarly journals Multiscale low-dimensional motor cortical state dynamics predict naturalistic reach-and-grasp behavior

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hamidreza Abbaspourazad ◽  
Mahdi Choudhury ◽  
Yan T. Wong ◽  
Bijan Pesaran ◽  
Maryam M. Shanechi
Keyword(s):  
Neural Control ◽  
Multiple Scales ◽  
Network Activity ◽  
Neural Dynamics ◽  
Population Activity ◽  
Reach And Grasp ◽  
Spatiotemporal Scales ◽  
Motor Cortical ◽  
Low Dimensional ◽  
Low Dimensional Dynamics

AbstractMotor function depends on neural dynamics spanning multiple spatiotemporal scales of population activity, from spiking of neurons to larger-scale local field potentials (LFP). How multiple scales of low-dimensional population dynamics are related in control of movements remains unknown. Multiscale neural dynamics are especially important to study in naturalistic reach-and-grasp movements, which are relatively under-explored. We learn novel multiscale dynamical models for spike-LFP network activity in monkeys performing naturalistic reach-and-grasps. We show low-dimensional dynamics of spiking and LFP activity exhibited several principal modes, each with a unique decay-frequency characteristic. One principal mode dominantly predicted movements. Despite distinct principal modes existing at the two scales, this predictive mode was multiscale and shared between scales, and was shared across sessions and monkeys, yet did not simply replicate behavioral modes. Further, this multiscale mode’s decay-frequency explained behavior. We propose that multiscale, low-dimensional motor cortical state dynamics reflect the neural control of naturalistic reach-and-grasp behaviors.

scholarly journals Grasping Social Apathy: The Role of Reach-To-Grasp Action Kinematics for the Assessment of Social Apathy in Mild Neurocognitive Disorders

2021 ◽  
pp. 1-14
Author(s):  
Valeria Manera ◽  
Guenda Galperti ◽  
Erika Rovini ◽  
Radia Zeghari ◽  
Gianmaria Mancioppi ◽  
...  
Keyword(s):  
Neurocognitive Disorders ◽  
Reach To Grasp ◽  
Future Studies ◽  
Clinical Scales ◽  
Non Invasive ◽  
Reach And Grasp ◽  
The Social ◽  
Self Reports ◽  
Individual Condition

Background: Social apathy, a reduction in initiative in proposing or engaging in social activities or interactions, is common in mild neurocognitive disorders (MND). Current apathy assessment relies on self-reports or clinical scales, but growing attention is devoted to defining more objective, measurable and non-invasive apathy proxies. Objective: In the present study we investigated the interest of recording action kinematics in a social reach-to-grasp task for the assessment of social apathy. Methods: Thirty participants took part in the study: 11 healthy controls (HC; 6 females, mean age = 68.3±10.5 years) and 19 subjects with MND (13 females, mean age = 75.7±6.3 years). Based on the Diagnostic Criteria for Apathy, MND subjects were classified as socially apathetic (A-MND, N = 9) versus non-apathetic (NA-MND, N = 10). SensRing, a ring-shaped wearable sensor, was placed on their index finger, and subjects were asked to reach and grasp a can to place it into a cup (individual condition) and pass it to a partner (social condition). Results: In the reach-to-grasp phase of the action, HC and NA-MND showed different acceleration and velocity profiles in the social versus individual condition. No differences were found for A-MND. Conclusion: Previous studies showed the interest of recording patients’ level of weekly motor activity for apathy assessment. Here we showed that a 10-min reach-to-grasp task may provide information to differentiate socially apathetic and non-apathetic subjects with MND, thus providing a tool easily usable in the clinical practice. Future studies with a bigger sample are needed to better characterize these findings.

Optimization of Dynamic Forces in the Design of Mechanical Hands

1989 ◽  
Author(s):  
M. A. Nahon ◽  
J. Angeles
Keyword(s):  
Equations Of Motion ◽  
Inequality Constraints ◽  
Kinematic Chain ◽  
Programming Approach ◽  
Quadratic Optimization Problem ◽  
System A ◽  
Redundantly Actuated ◽  
Internal Forces ◽  
Constrained Quadratic Optimization ◽  
Mechanical Hands

Abstract Mechanical hands have become of greater interest in robotics due to the advantages they offer over conventional grippers in tasks requiring dextrous manipulation. However, mechanical hands also tend to be more complex in construction and require more sophisticated design analysis to determine the forces in the system. A mechanical hand can be described as a kinematic chain with time-varying topology which becomes redundantly actuated when an object is grasped. When this occurs, care must be exercised to avoid crushing the object or generating excessive forces within the mechanism. In the present work, this problem is formulated as a constrained quadratic optimization problem. The forces to be minimized form the objective, the dynamic equations of motion form the equality constraints and the finger-object contacts yield the inequality constraints. The quadratic-programming approach is shown to be advantageous due to its ability to minimize ‘internal forces’ A technique is proposed for smoothing the discontinuities in the force solution which occur when the toplogy changes.

Reach and Grasp reconfigurations reveal that proprioception assists reaching and hapsis assists grasping in peripheral vision

2014 ◽  
Vol 232 (9) ◽  
pp. 2807-2819 ◽  
Author(s):  
Lauren A. Hall ◽  
Jenni M. Karl ◽  
Brittany L. Thomas ◽  
Ian Q. Whishaw
Keyword(s):  
Peripheral Vision ◽  
Reach And Grasp

Task-Specific Sensorimotor Adaptation to Reversing Prisms

2005 ◽  
Vol 93 (2) ◽  
pp. 1104-1110 ◽  
Author(s):  
Jonathan J. Marotta ◽  
Gerald P. Keith ◽  
J. Douglas Crawford
Keyword(s):  
Spatial Information ◽  
Training Session ◽  
Sensorimotor Adaptation ◽  
Opposite Pattern ◽  
Virtual Objects ◽  
Learning Rules ◽  
Reach And Grasp ◽  
Sensorimotor Transformations ◽  
Correct Location ◽  
Parallel Feature

We tested between three levels of visuospatial adaptation (global map, parallel feature modules, and parallel sensorimotor transformations) by training subjects to reach and grasp virtual objects viewed through a left-right reversing prism, with either visual location or orientation feedback. Even though spatial information about the global left-right reversal was present in every training session, subjects trained with location feedback reached to the correct location but with the wrong (reversed) grasp orientation. Subjects trained with orientation feedback showed the opposite pattern. These errors were task-specific and not feature-specific; subjects trained to correctly grasp visually reversed–oriented bars failed to show knowledge of the reversal when asked to point to the end locations of these bars. These results show that adaptation to visuospatial distortion—even global reversals—is implemented through learning rules that operate on parallel sensorimotor transformations (e.g., reach vs. grasp).

scholarly journals Electroencephalogram Source Imaging and Brain Network Based Natural Grasps Decoding

2021 ◽  
Vol 15 ◽  
Author(s):  
Baoguo Xu ◽  
Leying Deng ◽  
Dalin Zhang ◽  
Muhui Xue ◽  
Huijun Li ◽  
...  
Keyword(s):  
Parietal Lobe ◽  
Phase Locking ◽  
Brain Network ◽  
Internal Communication ◽  
Peak Performance ◽  
Source Imaging ◽  
Planning Stage ◽  
Grand Average ◽  
Reach And Grasp ◽  
Phase Locking Value

Studying the decoding process of complex grasping movement is of great significance to the field of motor rehabilitation. This study aims to decode five natural reach-and-grasp types using sources of movement-related cortical potential (MRCP) and investigate their difference in cortical signal characteristics and network structures. Electroencephalogram signals were gathered from 40 channels of eight healthy subjects. In an audio cue-based experiment, subjects were instructed to keep no-movement condition or perform five natural reach-and-grasp movements: palmar, pinch, push, twist and plug. We projected MRCP into source space and used average source amplitudes in 24 regions of interest as classification features. Besides, functional connectivity was calculated using phase locking value. Six-class classification results showed that a similar grand average peak performance of 49.35% can be achieved using source features, with only two-thirds of the number of channel features. Besides, source imaging maps and brain networks presented different patterns between each condition. Grasping pattern analysis indicated that the modules in the execution stage focus more on internal communication than in the planning stage. The former stage was related to the parietal lobe, whereas the latter was associated with the frontal lobe. This study demonstrates the superiority and effectiveness of source imaging technology and reveals the spread mechanism and network structure of five natural reach-and-grasp movements. We believe that our work will contribute to the understanding of the generation mechanism of grasping movement and promote a natural and intuitive control of brain–computer interface.

scholarly journals The effects of anxiety and dual-task on upper limb motor control of chronic stroke survivors

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mahnaz Hejazi-Shirmard ◽  
Laleh Lajevardi ◽  
Mehdi Rassafiani ◽  
Ghorban Taghizadeh
Keyword(s):  
Motor Control ◽  
Upper Limb ◽  
Dual Task ◽  
Chronic Stroke ◽  
Stroke Survivors ◽  
High Anxiety ◽  
Reach And Grasp ◽  
Stroke Group ◽  
Task Conditions ◽  
Hand Opening

Abstract This study was designed to investigate the effects of anxiety and dual-task on reach and grasp motor control in chronic stroke survivors compared with age- and sex-matched healthy subjects (HC). Reach and grasp kinematic data of 68 participants (high-anxiety stroke (HA-stroke), n = 17; low-anxiety stroke (LA-stroke), n = 17; low-anxiety HC, n = 17; and high-anxiety HC, n = 17) were recorded under single- and dual-task conditions. Inefficient reach and grasp of stroke participants, especially HA-stroke were found compared with the control groups under single- and dual-task conditions as evidenced by longer movement time (MT), lower and earlier peak velocity (PV) as well as delayed and smaller hand opening. The effects of dual-task on reach and grasp kinematic measures were similar between HCs and stroke participants (i.e., increased MT, decreased PV that occurred earlier, and delayed and decreased hand opening), with greater effect in stroke groups than HCs, and in HA-stroke group than LA-stroke group. The results indicate that performing a well-learned upper limb movement with concurrent cognitive task leads to decreased efficiency of motor control in chronic stroke survivors compared with HCs. HA-stroke participants were more adversely affected by challenging dual-task conditions, underlying importance of assessing anxiety and designing effective interventions for it in chronic stroke survivors.

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