scholarly journals Energy-related optimal control accounts for gravitational load: comparing shoulder, elbow, and wrist rotations

2014 ◽  
Vol 111 (1) ◽  
pp. 4-16 ◽  
Author(s):  
Jérémie Gaveau ◽  
Bastien Berret ◽  
Laurent Demougeot ◽  
Luciano Fadiga ◽  
Thierry Pozzo ◽  
...  
Keyword(s):  
Optimal Control ◽  
Planning Process ◽  
Vertical Plane ◽  
Motor Planning ◽  
Gravity Force ◽  
General Idea ◽  
Directional Asymmetry ◽  
Vertical Movements ◽  
Plane Joint ◽  
Experimental Findings

We permanently deal with gravity force. Experimental evidences revealed that moving against gravity strongly differs from moving along the gravity vector. This directional asymmetry has been attributed to an optimal planning process that optimizes gravity force effects to minimize energy. Yet, only few studies have considered the case of vertical movements in the context of optimal control. What kind of cost is better suited to explain kinematic patterns in the vertical plane? Here, we aimed to understand further how the central nervous system (CNS) plans and controls vertical arm movements. Our reasoning was the following: if the CNS optimizes gravity mechanical effects on the moving limbs, kinematic patterns should change according to the direction and the magnitude of the gravity torque being encountered in the motion. Ten subjects carried out single-joint movements, i.e., rotation around the shoulder (whole arm), elbow (forearm), and wrist (hand) joints, in the vertical plane. Joint kinematics were analyzed and compared with various theoretical optimal model predictions (minimum absolute work-jerk, jerk, torque change, and variance). We found both direction-dependent and joint-dependent variations in several kinematic parameters. Notably, directional asymmetries decreased according to a proximodistal gradient. Numerical simulations revealed that our experimental findings could be attributed to an optimal motor planning (minimum absolute work-jerk) that integrates the direction and the magnitude of gravity torque and minimizes the absolute work of forces (energy-related cost) around each joint. Present results support the general idea that the CNS implements optimal solutions according to the dynamic context of the action.

scholarly journals Spectrum of power laws for curved hand movements

2015 ◽  
Vol 112 (29) ◽  
pp. E3950-E3958 ◽  
Author(s):  
Dongsung Huh ◽  
Terrence J. Sejnowski
Keyword(s):  
Optimal Control ◽  
Motor Planning ◽  
Power Laws ◽  
Angular Frequency ◽  
Control Model ◽  
Hand Movements ◽  
Local Curvature ◽  
Scale Invariant ◽  
The Past ◽  
Invariant Features

In a planar free-hand drawing of an ellipse, the speed of movement is proportional to the −1/3 power of the local curvature, which is widely thought to hold for general curved shapes. We investigated this phenomenon for general curved hand movements by analyzing an optimal control model that maximizes a smoothness cost and exhibits the −1/3 power for ellipses. For the analysis, we introduced a new representation for curved movements based on a moving reference frame and a dimensionless angle coordinate that revealed scale-invariant features of curved movements. The analysis confirmed the power law for drawing ellipses but also predicted a spectrum of power laws with exponents ranging between 0 and −2/3 for simple movements that can be characterized by a single angular frequency. Moreover, it predicted mixtures of power laws for more complex, multifrequency movements that were confirmed with human drawing experiments. The speed profiles of arbitrary doodling movements that exhibit broadband curvature profiles were accurately predicted as well. These findings have implications for motor planning and predict that movements only depend on one radian of angle coordinate in the past and only need to be planned one radian ahead.

scholarly journals Reaction to a Visual Stimulus: Anticipation with Steady and Dynamic Contractions

2019 ◽  
Vol 69 (1) ◽  
pp. 17-27
Author(s):  
Agostina Casamento-Moran ◽  
Stefan Delmas ◽  
Seoung Hoon Park ◽  
Basma Yacoubi ◽  
Evangelos A. Christou
Keyword(s):  
Reaction Time ◽  
Planning Process ◽  
Dynamic Condition ◽  
Motor Planning ◽  
Reaction Time Task ◽  
Emg Activity ◽  
Time Interval ◽  
Variable Direction ◽  
The Moment ◽  
Study Participants

Abstract Reacting fast to visual stimuli is important for many activities of daily living and sports. It remains unknown whether the strategy used during the anticipatory period influences the speed of the reaction. The purpose of this study was to determine if reaction time (RT) differs following a steady and a dynamic anticipatory strategy. Twenty‐two young adults (21.0 ± 2.2 yrs, 13 women) participated in this study. Participants performed 15 trials of a reaction time task with ankle dorsiflexion using a steady (steady force at 15% MVC) and a dynamic (oscillating force from 10‐20% MVC) anticipatory strategy. We recorded primary agonist muscle (tibialis anterior; TA) electromyographic (EMG) activity. We quantified RT as the time interval from the onset of the stimulus to the onset of force. We found that a dynamic anticipatory strategy, compared to the steady anticipatory strategy, resulted in a longer RT (p = 0.04). We classified trials of the dynamic condition based on the level and direction of anticipatory force at the moment of the response. We found that RT was longer during the middle descending relative to the middle ascending and the steady conditions (p < 0.01). All together, these results suggest that RT is longer when preceded by a dynamic anticipatory strategy. Specifically, the longer RT is a consequence of the variable direction of force at which the response can occur, which challenges the motor planning process.

Feedforward and Feedback Optimal Control of Autonomous Profiling Monitoring Underwater Vehicle with Disturbance

2014 ◽  
Vol 602-605 ◽  
pp. 970-973 ◽  
Author(s):  
Hua Mu ◽  
Jian Yuan
Keyword(s):  
Optimal Control ◽  
Linear System ◽  
Feedback Linearization ◽  
Vertical Plane ◽  
Underwater Vehicle ◽  
Linearization Method ◽  
Control Law ◽  
Control Scheme ◽  
System States ◽  
Feedback Optimal Control

The optimal control of autonomous profiling monitoring underwater vehicle (APMUV) is investigated. Firstly, dynamics equations in vertical plane with disturbances are constructed, and the equations are converted into a linear system by feedback linearization method and then feedforward and feedback optimal control (FFOC) law is designed for the linear system. To solve the unpractical problem of the control law, we construct a disturbance observer to observe the system states to make a quick convergance of the observed system states. Numerical simulations show the effectiveness of the control scheme

Comparison of abstract decision encoding in the monkey prefrontal cortex, the presupplementary, and cingulate motor areas

2013 ◽  
Vol 110 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Katharina Merten ◽  
Andreas Nieder
Keyword(s):  
Prefrontal Cortex ◽  
Cognitive Processing ◽  
Planning Process ◽  
Motor Planning ◽  
Motor Preparation ◽  
Neuron Activity ◽  
Critical Element ◽  
Cingulate Motor Area ◽  
Monkey Prefrontal Cortex

Deciding between alternatives is a critical element of flexible behavior. Perceptual decisions have been studied extensively in an action-based framework. Recently, we have shown that abstract perceptual decisions are encoded in prefrontal cortex (PFC) neurons ( Merten and Nieder 2012 ). However, the role of other frontal cortex areas remained elusive. Here, we trained monkeys to perform a rule-based visual detection task that disentangled abstract perceptual decisions from motor preparation. We recorded the single-neuron activity in the presupplementary (preSMA) and the rostral part of the cingulate motor area (CMAr) and compared it to the results previously found in the PFC. Neurons in both areas traditionally identified with motor planning process the abstract decision independently of any motor preparatory activity by similar mechanisms as the PFC. A larger proportion of decision neurons and a higher strength of decision encoding was found in the preSMA than in the PFC. Neurons in both areas reliably predicted the monkeys' decisions. The fraction of CMAr decision neurons and their strength of the decision encoding were comparable to the PFC. Our findings highlight the role of both preSMA and CMAr in abstract cognitive processing and emphasize that both frontal areas encode decisions prior to the preparation of a motor output.

scholarly journals Multi-Joint Coordination of Vertical Arm Movement

2003 ◽  
Vol 1 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Ajay Seth ◽  
John J. McPhee ◽  
Marcus G. Pandy
Keyword(s):  
Sagittal Plane ◽  
Model Simulation ◽  
Vertical Plane ◽  
Arm Movement ◽  
Elbow Flexion ◽  
Vertical Acceleration ◽  
Joint Movement ◽  
Vertical Movements ◽  
Joint Coordination ◽  
Muscle Torques

A model of the human arm was developed to study coordination of multi-joint movement in the vertical plane. The arm was represented as a two-segment, two-degree of freedom dynamic system with net muscle torques acting at the shoulder and elbow. Kinematic data were collected from a subject who performed unrestrained vertical movements with only the initial and final hand elevations prescribed. Movements were performed with and without a hand-held load. The method of computed torques was implemented to obtain net muscle torques, which enables position and velocity feedback to be used to estimate joint angular accelerations that produce a more stable simulation of arm movement. The model simulation was then used to calculate the contributions of the net muscle torques, gravitational torques and velocity-interaction torques to the angular accelerations of the shoulder and elbow and also to the vertical acceleration of the hand. The net muscle torques and gravity were the prime movers of the arm. The velocity-dependent effects contributed little to the dynamics of arm movement and were, in fact, insignificant when the hand was loaded. The muscles of the shoulder and elbow acted synergistically to elevate the arm in the sagittal plane. The hand was accelerated upward by the elbow first, until the point of maximum elbow flexion, after which the shoulder became the prime mover. Gravity acted consistently to accelerate the hand downward. Coordination was notably invariant to changes in external load. Some compensation for load was observed in the control, and these differences were attributed mainly to an increase in system inertia.

Research on How to Work out Equipment Technical Data

2013 ◽  
Vol 765-767 ◽  
pp. 3236-3240
Author(s):  
Xue Zheng Zhu ◽  
Kun Lin Nie ◽  
Jing Hui Li ◽  
Hui Hao ◽  
Yan Li ◽  
...  
Keyword(s):  
Planning Process ◽  
Critical Role ◽  
Planning Method ◽  
General Idea ◽  
Technical Data ◽  
Combat Effectiveness ◽  
Systematic Planning

Scientific and logical planning of technical data, which is the foundation to equip technical data efficiently, is an effective way to quickly transfer the equipment into combat effectiveness and support capability. With the transformation of war pattern and increase of equipment complexity, the critical role of equipment technical data in equipment support has become increasingly prominent. This paper focuses on the effective way to work out systematic planning method of equipment technical data. Beginning with equipment technical data concept and status, the paper studies the general idea of equipment technical data planning, makes deep analysis of specific planning process, and puts forward an instructive output model. It is expected to offer an instruction to scientific planning of equipment technical data, so as to accelerate transformation of new equipment into combat effectiveness, and improve equipment support capacity.

scholarly journals Motor planning of vertical arm movements in healthy older adults: does effort optimization persist with aging?

2019 ◽  
Author(s):  
Gabriel Poirier ◽  
Charalambos Papaxanthis ◽  
France Mourey ◽  
Jeremie Gaveau
Keyword(s):  
Older Adults ◽  
Healthy Aging ◽  
Peak Velocity ◽  
Motor Planning ◽  
Adverse Outcomes ◽  
The Body ◽  
Vertical Movements ◽  
Healthy Older Adults ◽  
Arm Reaching ◽  
Directional Asymmetries

AbstractSeveral sensorimotor modifications are known to occur with aging, possibly leading to adverse outcomes such as falls. Recently, some of those modifications have been proposed to emerge from motor planning deteriorations. Motor planning of vertical movements is thought to engage an internal model of gravity to anticipate its mechanical effects on the body-limbs and thus to genuinely produce movements that minimize muscle effort. This is supported, amongst other results, by direction-dependent kinematics where relative durations to peak accelerations and peak velocity are shorter for upward than for downward movements. The present study compares motor planning of fast and slow vertical arm reaching movements between eighteen young (24 ± 3 years old) and seventeen older adults (70 ± 5 years old). We found that older participants still exhibit directional asymmetries (i.e., differences between upward and downward movements), indicating that optimization processes during motor planning persist with healthy aging. However, the size of these differences was increased in older participants, indicating that gravity-related motor planning changes with age. We discuss this increase as the possible result of an overestimation of gravity torque or increased weight of the effort cost in the optimization process. Overall, these results support the hypothesis that feedforward processes and, more precisely, optimal motor planning, remain active with healthy aging.

Transportation Work of Gel Object Done by a Paramecium in the Vertical Plane Pool

2017 ◽  
Author(s):  
Nozomi Hayasaka ◽  
Takumi Kikuchi ◽  
Akitoshi Itoh
Keyword(s):  
Motion Control ◽  
Swimming Speed ◽  
Vertical Plane ◽  
Target Object ◽  
Target Point ◽  
Hard Material ◽  
Vertical Movements ◽  
Upward Direction ◽  
The Difference ◽  
Set Up

We have been investigating how to use microorganisms for bio-micromachines. In this paper, we investigated the motion control property of Paramecium in the vertical plane to prepare the real 3-dimensional motion control. First, we developed a motion control pool for the vertical set up. Basically, the controllability of Paramecium in the vertical plane is not so different to the controllability in the horizontal plane. We can control paramecium very stably for over 100 laps along the star-shaped target route by using this newly made experimental pool. The controllability was improved with the progression of making a circuit. It may relate to the dropping of the swimming speed. The swimming trace, however, showed the peculiarity that related to the vertical movements. The swimming speed of the downward direction is higher than that of the upward direction. The overrun on the downward route was larger than that on the upward route in the vertical plane. It was caused by the difference of the swimming speed on each of routes. Therefore, we developed a new motion control algorithm to decrease this overrun. In our former algorithm, the change timing of the target point was decided by the previous change timing and the previous turning point. In the new algorithm, we change this adjusting method to refer the same target point of the past laps using smoothing value calculated by the integral of the equal ratio attenuation. By using this adjustment method, we succeeded to decrease the overrun. We also investigated the transportability of the object by using motion controlled paramecium in the vertical pool. We found that paramecia often cause their avoiding reaction when they hit object made of hard material. In the case of the object made of soft material, paramecia can push more often and more easily. Therefore, we decided to change the target object from hard plastic to soft gel. We succeeded to transport and drop a gel oval sphere to the target place by manually controlled paramecium in the vertical plane pool.

scholarly journals Development of motor planning in children: Disentangling elements of the planning process

2020 ◽  
Vol 199 ◽  
pp. 104945
Author(s):  
Hilde Krajenbrink ◽  
Jessica Lust ◽  
Peter Wilson ◽  
Bert Steenbergen
Keyword(s):  
Planning Process ◽  
Motor Planning
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