scholarly journals Immediate compensation for variations in self-generated Coriolis torques related to body dynamics and carried objects

2013 ◽  
Vol 110 (6) ◽  
pp. 1370-1384 ◽  
Author(s):  
Pascale Pigeon ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Dynamic Properties ◽  
Arm Movement ◽  
The Body ◽  
Joint Torque ◽  
Movement Trajectory ◽  
Joint Torques ◽  
Intersegmental Dynamics ◽  
The Right ◽  
Dynamic Dominance ◽  
Interaction Torques

We have previously shown that the Coriolis torques that result when an arm movement is performed during torso rotation do not affect movement trajectory. Our purpose in the present study was to examine whether torso motion-induced Coriolis and other interaction torques are counteracted during a turn and reach (T&R) movement when the effective mass of the hand is augmented, and whether the dominant arm has an advantage in coordinating intersegmental dynamics as predicted by the dynamic dominance hypothesis (Sainburg RL. Exp Brain Res 142: 241–258, 2002). Subjects made slow and fast T&R movements in the dark to just extinguished targets with either arm, while holding or not holding a 454-g object. Movement endpoints were equally accurate at both speeds, with either hand, and in both weight conditions, but subjects tended to angularly undershoot and produce more variable endpoints for targets requiring greater torso rotation. There were no changes in endpoint accuracy or trajectory deviation over repeated movements. The dominant right arm was more stable in its control of trajectory direction across targets, whereas the nondominant left arm had an improved ability to stop accurately on the target for higher levels of interaction torques. The trajectories to more eccentric targets were straighter when performed at higher speeds but slightly more deviated when subjects held the weight. Subjects did not slow their torso velocity or change the timing of the arm and torso velocities when holding the weight, although there was a slight decrease in their hand velocity relative to the torso. The delay between the onsets of torso and finger movements was almost twice as large for the right arm than the left, suggesting the right arm was better able to account for torso rotation in the arm movement. Holding the weight increased the peak Coriolis torque by 40% at the shoulder and 45% at the elbow and, for the most eccentric target, increased the peak net torque by 12% at the shoulder and 34% at the elbow. In accordance with Sainburg's dynamic dominance hypothesis, the right arm exhibited an advantage for coordinating intersegmental dynamics, showing a more stable finger velocity in relation to the torso across targets, decreasing error variability with movement speed, and more synchronized peaks of finger relative and torso angular velocities in conditions with greater joint torque requirements. The arm used had little effect on the movement path and the magnitude of the joint torques in any of the conditions. These results indicate that compensations for forthcoming Coriolis torque variations take into account the dynamic properties of the body and of external objects, as well as the planned velocities of the torso and arm.

Directional Control of Planar Human Arm Movement

1997 ◽  
Vol 78 (6) ◽  
pp. 2985-2998 ◽  
Author(s):  
Gerald L. Gottlieb ◽  
Qilai Song ◽  
Gil L. Almeida ◽  
Di-An Hong ◽  
Daniel Corcos
Keyword(s):  
Control System ◽  
Arm Movement ◽  
Initial Position ◽  
Joint Torque ◽  
Reaching Movements ◽  
Rule Based ◽  
Joint Torques ◽  
Directional Control ◽  
Human Arm ◽  
Dynamic Components

Gottlieb, Gerald L., Qilai Song, Gil L. Almeida, Di-an Hong, and Daniel Corcos. Directional control of planar human arm movement. J. Neurophysiol. 78: 2985–2998, 1997. We examined the patterns of joint kinematics and torques in two kinds of sagittal plane reaching movements. One consisted of movements from a fixed initial position with the arm partially outstretched, to different targets, equidistant from the initial position and located according to the hours of a clock. The other series added movements from different initial positions and directions and >40–80 cm distances. Dynamic muscle torque was calculated by inverse dynamic equations with the gravitational components removed. In making movements in almost every direction, the dynamic components of the muscle torques at both the elbow and shoulder were related almost linearly to each other. Both were similarly shaped, biphasic, almost synchronous and symmetrical pulses. These findings are consistent with our previously reported observations, which we termed a linear synergy. The relative scaling of the two joint torques changes continuously and regularly with movement direction. This was confirmed by calculating a vector defined by the dynamic components of the shoulder and elbow torques. The vector rotates smoothly about an ellipse in intrinsic, joint torque space as the direction of hand motion rotates about a circle in extrinsic Cartesian space. This confirms a second implication of linear synergy that the scaling constant between the linearly related joint torques is directionally dependent. Multiple linear regression showed that the torque at each joint scales as a simple linear function of the angular displacement at both joints, in spite of the complex nonlinear dynamics of multijoint movement. The coefficients of this function are independent of the initial arm position and movement distance and are the same for all subjects. This is an unanticipated finding. We discuss these observations in terms of the hypothesis that voluntary, multiple degrees of freedom, rapid reaching movements may use rule-based, feed-forward control of dynamic joint torque. Rule-based control of joint torque with separate dynamic and static controllers is an alternative to models such as those based on the equilibrium point hypotheses that rely on a positionally based controller to produce both dynamic and static torque components. It is also an alternative to feed-forward models that directly solve the problems of inverse dynamics. Our experimental findings are not necessarily incompatible with any of the alternative models, but they describe new, additional findings for which we need to account. The rules are chosen by the nervous system according to features of the kinematic task to couple muscle contraction at the shoulder and elbow in a linear synergy. Speed and load control preserves the relative magnitudes of the dynamic torques while directional control is accomplished by modulating them in a differential manner. This control system operates in parallel with a positional control system that solves the problems of postural stability.

scholarly journals Optimization of Coupling Ratio and Kinematics of an Underactuated Robot Leg for Passive Terrain Adaptability

2012 ◽  
Author(s):  
Oren Y. Kanner ◽  
Aaron M. Dollar
Keyword(s):  
Performance Metrics ◽  
Reaction Force ◽  
The Body ◽  
Joint Torque ◽  
Design Parameters ◽  
Leg Length ◽  
Coupling Ratio ◽  
Joint Torques ◽  
Robot Leg ◽  
Underactuated Robot

This paper investigates how the passive adaptability of an underactuated robot leg to uneven terrain is affected by variations in design parameters. In particular, the ratio between the joint torques, the ratio between the link lengths, and the initial joint rest angles are varied to determine configurations that allow for maximum terrain roughness adaptability while minimizing the transmission of disturbance forces to the body. The results show that a proximal/distal joint torque coupling ratio of 1.58, proximal/distal leg length ratio of 0.5, and an initial proximal joint angle of −49 degrees maximize the terrain variability over which the robot can remain stable by exerting a near-constant vertical reaction force while minimizing lateral force and moment disturbances. In addition, the spring stiffness ratio allows for a tradeoff to be made between the different performance metrics.

A Postural Model of Balance-Correcting Movement Strategies

1992 ◽  
Vol 2 (4) ◽  
pp. 323-347
Author(s):  
J.H.J. Allum ◽  
F. Honegger
Keyword(s):  
Normal Subjects ◽  
Opposite Polarity ◽  
The Body ◽  
Joint Torque ◽  
Support Surface ◽  
Joint Torques ◽  
Eyes Closed ◽  
Movement Strategies ◽  
Eyes Open ◽  
Balance Corrections

The patterns of joint torques and movement strategies underlying human balance corrections were examined using a postural model. Two types of support-surface perturbation, dorsiflexion rotation (ROT) and rearward translation (TRANS), were employed. These two perturbations were adjusted to produce similar profiles of ankle dorsiflexion in order to obtain information on the role of lower leg proprioceptive inputs on triggering balance corrections. In addition, the dependence of balance control on head angular and linear accelerations was investigated by comparing the responses of normal and vestibularly deficient subjects under eyes-closed and eyes-open conditions. Differences in ROT and TRANS movement strategies were examined in three ways First, the amplitude and polarity of active joint torques were analysed. These were obtained by altering joint torques applied to a postural model until movements of the model accurately duplicated those of measured responses. Second, the pattern of body-segment angular movements depicted by stick figures moving in response to the computed joint torques was investigated. Third, the peak amplitude and patterns of crosscorrelations between joint torques were measured. Active ankle, knee, and hip joint torques computed for normal subjects rotated the body forward for ROT. In the case of TRANS, computed active torques in normal were of opposite polarity to those of ROT and reversed the forward motion of the body. Subjects with vestibular deficits had lower amplitude torques for ROT and failed to counter the platform rotation. Hip torques for TRANS in vestibular deficient subjects were of opposite polarity to those of normal subjects and resulted in excessive forward trunk rotation. Normally, neck torques acted to stabilize the head in space when trunk angular velocity peaked. Vestibular deficient subjects displayed head movements in response to ROT similar to those generated when neck torques were absent. For TRANS, these same subjects exhibited overcompensatory neck torques. Stick figures of normal responses indicated a stiffening of the body into a leg and a trunk-head link for ROT and a flexible multilink motion for TRANS. Likewise, normal response strategies, defined by using crosscorrelations of joint torques, differed for ROT and TRANS. All joint torque crosscorrelations were significant for TRANS. Neck torques led those of all other joint torques by 40 ms or more, and hip joint led ankle torques by 30 ms. Joint torque correlations for ROT were organised around hip and ankle torques without a major correlation to neck torques. Fundamental changes in all torque crosscorrelations occurred for vestibularly deficient subjects under both eyes-open and eyes-closed conditions. These results support the hypothesis that the modulation of postural responses by vestibular signals occurs at all major joint links of the upright human body and that the strategy underlying balance corrections at the hip and neck is selected independent of local sensory input from the lower leg. Rearward translation and dorsiflexion rotation of a support-surface elicit different movement strategies when ankle angle, changes are matched for such disturbances to human upright balance.

scholarly journals Kinematics of Initiating a Two-Joint Arm Movement in Patients with Cerebellar Ataxia

1996 ◽  
Vol 23 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Steve Massaquoi ◽  
Mark Hallett
Keyword(s):  
Cerebellar Ataxia ◽  
Arm Movement ◽  
Normal Subjects ◽  
Joint Torque ◽  
Angular Deviation ◽  
Wide Range ◽  
Task Requirements ◽  
Angular Velocities ◽  
Path Curvature ◽  
The Right

ABSTRACT:Objective:To characterize kinematically any systematic aberration in multi-joint movements in cerebellar ataxia.Methods:Nine patients with cerebellar degeneration and nine normal subjects, mobile only at the shoulder and elbow of the right arm, were required to produce left-to-right cross-body linear hand trajectories on the horizontal surface of a digitizing tablet. Nonlinearity indicated failure of precise coordination of the two joints. A wide range of hand speeds was studied. Data analysis was restricted primarily to the first 130 ms of movement.Results:As hand velocities increased, normal subjects and, especially, patients produced misdirected, curved paths. Normal subjects had significant curvature when peak speeds exceeded 100 cm/s and a trend toward significant bi-directional angular deviation at velocities greater than 300 cm/s. In patients, peak path curvature was significantly greater than normal at peak velocities of 50 to 200 cm/s. By 3.3 cm, their paths deviated significantly outward at all but the slowest speeds. Overall, patients’ maximal hand velocities and shoulder angular velocities, as well as maximal angular accelerations at both joints, were significantly lower than normal.Conclusions:The patients’ trajectory aberrations were attributed to a deficient rate of rotation at the shoulder relative to that at the elbow. Relative to task requirements, their rate of torque development was apparently deficient at both joints, but to a greater degree at the shoulder. Joint torque-rate impairment may contribute to the ataxia in both multi- and single-joint movements of patients with cerebellar disorders. A similar, but smaller impairment may produce milder nonlinearity in high-velocity movements of normal subjects.

scholarly journals Stroke Leads to Abnormal Coordination of the Multiple Upper Extremity Joints During Passive Movement

2020 ◽  
Author(s):  
Kyung Koh ◽  
Dongwon Kim ◽  
Giovanni Oppizzi ◽  
Chunyang Zhang ◽  
Glenn Kehs ◽  
...  
Keyword(s):  
Upper Extremity ◽  
Motor Impairment ◽  
Arm Movement ◽  
Passive Movement ◽  
The Body ◽  
Uncontrolled Manifold ◽  
Control Group ◽  
Joint Torques ◽  
Stroke Group ◽  
Coordination Patterns

Abstract Background Motor impairments in the upper extremity (UE) is one of the most common deficits after stroke. Even though understanding of UE coordination deficits in persons with strokes is critical for better identification of motor impairment and planning for rehabilitation, it is still not clear how stroke affects coordination patterns of multi-joint movements in the UE. Here, we investigated kinematic and kinetic coordination patterns of UE after stroke during controlled passive arm movement. Methods An exoskeleton multi-joint robot moved the participant’s arm in the horizontal plane back and forth in 8 repetitions, in inward movement (i.e. toward the body) and outward movement (i.e. away from the body). The uncontrolled manifold analysis (UCM) was used to quantify kinematic and kinetic coordination patterns of the UE. Variability of joint angles and torques were decomposed into task-relevant variability (TRV) and task-irrelevant variability (TIV). An index of coordination (IC) was defined based on TRV and TIV. Results We found that the IC of joint torques in the stroke group significantly decreased during outward movement in comparison to that during inward movement, while IC of the control group showed no difference between the two movement directions. The decreased IC in the stroke group during outward movement was mainly due to the increased TRV of joint torques. In the further analysis of individual joint level, during outward movement, stroke group had a greater TRV of joint torques at all joints while during inward movement, stroke group had a lower TRV of joint torques at elbow joint. Conclusions Our results indicate that the stroke can cause the kinetic coordination deficits induced during a passive movement especially in outward movement. Our findings suggest that it is important to consider the passive kinetic coordination deficits to enhance post-stroke rehabilitation interventions. Trial registration clinicaltrials.gov, ID: NCT02359812. Registered 23 January 2015; Last Updated 06 August 2020.

scholarly journals Effects of body movement on yaw motion in bipedal running lizard by dynamic simulation

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243798
Author(s):  
Jeongryul Kim ◽  
Hongmin Kim ◽  
Jaeheung Park ◽  
Hwa Soo Kim ◽  
TaeWon Seo
Keyword(s):  
Dynamic Simulation ◽  
Body Movement ◽  
The Body ◽  
Joint Torque ◽  
Stride Frequency ◽  
Body Movements ◽  
Joint Torques ◽  
Biomechanical Simulation ◽  
Bipedal Gait ◽  
The Relationship

Lizards run quickly and stably in a bipedal gait, with their bodies exhibiting a lateral S-shaped undulation. We investigate the relationship between a lizard’s bipedal running and its body movement with the help of a dynamic simulation. In this study, a dynamic theoretical model of lizard is assumed as a three-link consisting of an anterior and posterior bodies, and a tail, with morphometrics based on Callisaurus draconoides. When a lizard runs straight in a stable bipedal gait, its pelvic rotation is periodically synchronized with its gait. This study shows that the S-shaped body undulation with the yaw motion is generated by minimizing the square of joint torque. Furthermore, we performed the biomechanical simulation to figure out the relationship between the lizard’s lateral body undulation and the bipedal running locomotion. In the biomechanical simulation, all joint torques significantly vary by the waist and tail’ motions at the same locomotion. Besides, when the waist and tail joint angles increase, the stride length and duration of the model also increase, and the stride frequency decreases at the same running speed. It means that the lizard’s undulatory body movements increase its stride and help it run faster. In this study, we found the benefits of the lizard’s undulatory body movement and figured out the relationship between the body movement and the locomotion by analyzing the dynamics. In the future works, we will analyze body movements under different environments with various simulators.

Coordinated Turn-and-Reach Movements. I. Anticipatory Compensation for Self-Generated Coriolis and Interaction Torques

2003 ◽  
Vol 89 (1) ◽  
pp. 276-289 ◽  
Author(s):  
Pascale Pigeon ◽  
Simone B. Bortolami ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Radial Distance ◽  
The Body ◽  
Reaching Movements ◽  
Slow Rotation ◽  
Trunk Rotation ◽  
Joint Torques ◽  
Coriolis Forces ◽  
Movement Trajectories ◽  
Additional Interaction ◽  
Interaction Torques

When reaching movements involve simultaneous trunk rotation, additional interaction torques are generated on the arm that are absent when the trunk is stable. To explore whether the CNS compensates for such self-generated interaction torques, we recorded hand trajectories in reaching tasks involving various amplitudes and velocities of arm extension and trunk rotation. Subjects pointed to three targets on a surface slightly above waist level. Two of the target locations were chosen so that a similar arm configuration relative to the trunk would be required for reaching to them, one of these targets requiring substantial trunk rotation, the other very little. Significant trunk rotation was necessary to reach the third target, but the arm's radial distance to the body remained virtually unchanged. Subjects reached at two speeds—a natural pace (slow) and rapidly (fast)—under normal lighting and in total darkness. Trunk angular velocity and finger velocity relative to the trunk were higher in the fast conditions but were not affected by the presence or absence of vision. Peak trunk velocity increased with increasing trunk rotation up to a maximum of 200°/s. In slow movements, peak finger velocity relative to the trunk was smaller when trunk rotation was necessary to reach the targets. In fast movements, peak finger velocity was ∼1.7 m/s for all targets. Finger trajectories were more curved when reaching movements involved substantial trunk rotation; however, the terminal errors and the maximal deviation of the trajectory from a straight line were comparable in slow and fast movements. This pattern indicates that the larger Coriolis, centripetal, and inertial interaction torques generated during rapid reaches were compensated by additional joint torques. Trajectory characteristics did not vary with the presence or absence of vision, indicating that visual feedback was unnecessary for anticipatory compensations. In all reaches involving trunk rotation, the finger movement generally occurred entirely during the trunk movement, indicating that the CNS did not minimize Coriolis forces incumbent on trunk rotation by sequencing the arm and trunk motions into a turn followed by a reach. A simplified model of the arm/trunk system revealed that additional interaction torques generated on the arm during voluntary turning and reaching were equivalent to ≤1.8 g (1 g = 9.81 m/s2) of external force at the elbow but did not degrade performance. In slow-rotation room studies involving reaching movements during passive rotation, Coriolis forces as small as 0.2 g greatly deflect movement trajectories and endpoints. We conclude that compensatory motor innervations are engaged in a predictive fashion to counteract impending self-generated interaction torques during voluntary reaching movements.

On the Use of Induced End Effector Force Analysis for Determining Muscle Roles During Movement

2007 ◽  
Author(s):  
Stephen J. Piazza ◽  
Vladimir M. Zatsiorsky
Keyword(s):  
Electrical Stimulation ◽  
Muscle Function ◽  
Muscle Force ◽  
Human Movement ◽  
The Body ◽  
Joint Torque ◽  
Force Analysis ◽  
End Effector ◽  
Joint Torques ◽  
Muscle Strengthening

It is often of interest in studies of human movement to quantify the function of a muscle force or muscular joint torque. Such information is useful for the identification of the causes of movement disorders and for predicting the effects of interventions including surgical procedures, targeted muscle strengthening, focal treatments for spasticity, and functional electrical stimulation. One useful way to characterize the actions of muscle forces or muscular joint torques is to create linked-segment models of the body and analyze these linkages to determine the joint angular accelerations or end effector forces that result solely from the application of the muscle force or torque in question. Such induced acceleration (IA) analyses or induced end effector force (IEF) analyses have been applied most often to quantify muscle function during normal and pathological walking [1,2].

Atypical gunshot injury to the neck with an unexpected nonlinear bullet trajectory: a case report and review of the literature

2020 ◽  
Author(s):  
Yuuki Matsui ◽  
Sena Iguchi ◽  
Emiri Sato ◽  
Yoichiro Sato ◽  
Ken Shindo ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Body Movement ◽  
Neck Region ◽  
Body Awareness ◽  
The Body ◽  
Gunshot Injury ◽  
Retropharyngeal Space ◽  
Related Factors ◽  
Gunshot Injuries ◽  
The Right

Abstract Background Gunshot injuries involving the head and neck region yield profound morbidity and mortality rates because of the region’s dense structure occupied with essential organs. Both projectile- and tissue-related factors determine the disruptive effects of projectiles on living tissues, with the former comprising various physical and dynamic properties of a bullet. Although a bullet generally passes straight through the body, we experienced an unusual case of a gunshot injury to the neck, wherein the bullet penetrated through the deep structures to the contralateral side of the shoulder without damaging any vital organs, allowing us to discuss the diagnostic implications of wound ballistics in managing gunshot wounds with unexpected bullet trajectories. Case presentation A 51-year-old man presented with a gunshot wound to the neck from a point-blank range shooting during a local gang conflict. On admission, a bullet entry hole was observed on the left side of the neck without an exit hole; however, the patient was conscious; vital signs were normal; and no active bleeding, cranial nerve palsy, or aero-digestive tract injury were found. Imaging tests revealed a bullet lying in front of the right humeral head, a comminuted fracture of the right clavicle, and soft tissue edema and small air sacs among the deep neck structures, including the retropharyngeal space. Emergency surgery was performed to extract the bullet, which turned out to be a full metal-jacketed bullet. Five days later, the patient was uneventfully discharged. According to the localization of the damaged tissues and the positional relationship between the bullet’s entrance and its destination, we estimated that the bullet nonlinearly penetrated the neck through the interstructural spaces associated with the least tissue resistance, almost transversely, during its intra-body movement. Conclusion Our experience strongly suggests the importance of realizing the unpredictable nature of a bullet trajectory in a body. Awareness of various ballistic factors and wounding mechanisms, which affect a bullet trajectory and the magnitude of tissue damage, can be of great help in adequate assessment and management of patients with gunshot injuries.

scholarly journals Time of Fast Learning in Speed-Accuracy Tasks is Different for Children and Adults

2018 ◽  
Vol 1 (80) ◽  
Author(s):  
Kristina Motiejūnaitė ◽  
Dalia Mickevičienė ◽  
Albertas Skurvydas ◽  
Kazimieras Pukėnas ◽  
Diana Karanauskienė ◽  
...  
Keyword(s):  
Reaction Time ◽  
Motor Learning ◽  
Arm Movement ◽  
Movement Speed ◽  
Movement Trajectory ◽  
Manual Task ◽  
Fast Learning ◽  
Learning Speed ◽  
The Right ◽  
Speed Accuracy

Research background and hypothesis. Motor learning is characterized by specific set of changes in performance parameters which occur gradually over a course of learning period.Research aim. The aim of the study was to establish and compare the characteristics of learning speed-accuracy movements of children and adults. Research methods. The research participants were 13 healthy boys, 16 girls, 5 healthy men and 7 women. The research was carried out applying the analyzer of dynamic parameters of human leg and arm movement (DPA-1). We registered maximal and average movement speed, the reaction time and the movement trajectory of the right hand. Research results. We established signifi cant differences (p < 0.05–0.001) in reaction time (RT), average movement speed (Va), maximal movement speed (Vm) and movement trajectory (S) between children and adults. Discussion and conclusions. Motor adaptation in timescales of minutes is supported by two distinct processes: one process when a person learns slowly from errors but has strong retention, and another process is when a person learns rapidly from errors but has poor retention (Ethier et al., 2008). We might only speculate that children used the second strategy more than adults. The time of fast learning in a speed-accuracy task was different between children and adults. The accuracy was most improved by children at the expense of the quickness, while adults improved only the average velocity of their performance. Besides, most of the variability of performance variables changed more signifi cantly in children than in adults.Keywords: motor learning, motor control, age, manual task.

Sign in / Sign up

Export Citation Format

Share Document