scholarly journals Analysis of Human Whole-Body Joint Torques During Overhead Work With a Passive Exoskeleton

2021 ◽  
pp. 1-9
Author(s):  
Claudia Latella ◽  
Yeshasvi Tirupachuri ◽  
Luca Tagliapietra ◽  
Lorenzo Rapetti ◽  
Benjamin Schirrmeister ◽  
...  
Keyword(s):  
Whole Body ◽  
Joint Torques ◽  
Passive Exoskeleton ◽  
Body Joint

Model-Based Design and Optimization of Passive Shoulder Exoskeletons

2021 ◽  
Author(s):  
Ali Nasr ◽  
Spencer Ferguson ◽  
John McPhee
Keyword(s):  
Elevation Angle ◽  
Differential Algebraic Equations ◽  
Joint Torque ◽  
Algebraic Equations ◽  
Joint Torques ◽  
Design And Optimization ◽  
Passive Mechanism ◽  
Wide Range ◽  
Passive Exoskeleton ◽  
Selection Of

Abstract To physically assist workers in reducing musculoskeletal strain or to develop motor skills for patients with neuromuscular disabilities, recent research has focused on Exoskeletons (Exos). Designing active Exos is challenging due to the complex human geometric structure, the human-Exoskeleton wrench interaction, the kinematic constraints, and the selection of power source characteristics. Because of the portable advantages of passive Exos, designing a passive shoulder mechanism has been studied here. The study concentrates on modeling a 3D multibody upper-limb human-Exoskeleton, developing a procedure of analyzing optimal assistive torque profiles, and optimizing the passive mechanism features for desired tasks. The optimization objective is minimizing the human joint torques. For simulating the complex closed-loop multibody dynamics, differential-algebraic equations (DAE)s of motion have been generated and solved. Three different tasks have been considered, which are common in industrial environments: object manipulation, over-head work, and static pointing. The resulting assistive Exoskeleton’s elevation joint torque profile could decrease the specific task’s human shoulder torque. Since the passive mechanism produces a specific torque for a given elevation angle, the Exoskeleton is not versatile or optimal for different dynamic tasks. We concluded that designing a passive Exoskeleton for a wide range of dynamic applications is impossible. We hypothesize that augmenting an actuator to the mechanism can provide the necessary adjustment torque and versatility for multiple tasks.

Robust Bipedal Locomotion Based on a Hierarchical Control Structure

Robotica ◽  
2019 ◽  
Vol 37 (10) ◽  
pp. 1750-1767 ◽  
Author(s):  
Jianwen Luo ◽  
Yao Su ◽  
Lecheng Ruan ◽  
Ye Zhao ◽  
Donghyun Kim ◽  
...  
Keyword(s):  
Center Of Pressure ◽  
Center Of Mass ◽  
Hierarchical Control ◽  
Middle Level ◽  
Smooth Transition ◽  
Whole Body ◽  
Joint Torques ◽  
Low Level ◽  
Hybrid Controller ◽  
High Level

SummaryTo improve biped locomotion’s robustness to internal and external disturbances, this study proposes a hierarchical structure with three control levels. At the high level, a foothold sequence is generated so that the Center of Mass (CoM) trajectory tracks a planned path. The planning procedure is simplified by selecting the midpoint between two consecutive Center of Pressure (CoP) points as the feature point. At the middle level, a novel robust hybrid controller is devised to drive perturbed system states back to the nominal trajectory within finite cycles without chattering. The novelty lies in that the hybrid controller is not subject to linear CoM dynamic constraints. The hybrid controller consists of two sub-controllers: an oscillation controller and a smoothing controller. For the oscillation controller, the desired CoM height is specified as a sine-shaped function, avoiding a new attractive limit cycle. However, this controller results in the inevitable chattering because of discontinuities. A smoothing controller provides continuous properties and thus can inhibit the chattering problem, but has a smaller region of attraction compared with the oscillation controller. A hybrid controller merges the two controllers for a smooth transition. At the low level, the desired CoM motion is defined as tasks and embedded in a whole body operational space (WBOS) controller to compute the joint torques analytically. The novelty of the low-level controller lies in that within the WBOS framework, CoM motion is not subject to fixed CoM dynamics and thus can be generalized.

scholarly journals Simultaneous Floating-Base Estimation of Human Kinematics and Joint Torques

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2794 ◽  
Author(s):  
Claudia Latella ◽  
Silvio Traversaro ◽  
Diego Ferigo ◽  
Yeshasvi Tirupachuri ◽  
Lorenzo Rapetti ◽  
...  
Keyword(s):  
Motion Tracking ◽  
Tracking System ◽  
Joint Torque ◽  
Whole Body ◽  
Joint Torques ◽  
Floating Base ◽  
Fixed Base ◽  
Human Estimation ◽  
External Forces ◽  
Motion Tracking System

The paper presents a stochastic methodology for the simultaneous floating-base estimation of the human whole-body kinematics and dynamics (i.e., joint torques, internal and external forces). The paper builds upon our former work where a fixed-base formulation had been developed for the human estimation problem. The presented approach is validated by presenting experimental results of a health subject equipped with a wearable motion tracking system and a pair of shoes sensorized with force/torque sensors while performing different motion tasks, e.g., walking on a treadmill. The results show that joint torque estimates obtained by using floating-base and fixed-base approaches match satisfactorily, thus validating the present approach.

Consistent accuracy in whole-body joint kinetics during gait using wearable inertial motion sensors and in-shoe pressure sensors

2015 ◽  
Vol 42 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Tsolmonbaatar Khurelbaatar ◽  
Kyungsoo Kim ◽  
SuKyoung Lee ◽  
Yoon Hyuk Kim
Keyword(s):  
Pressure Sensors ◽  
Whole Body ◽  
Motion Sensors ◽  
Inertial Motion ◽  
Joint Kinetics ◽  
Body Joint

scholarly journals Goal-Oriented Optimization of Dynamic Simulations to Find a Balance between Performance Enhancement and Injury Prevention during Volleyball Spiking

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 598
Author(s):  
Dhruv Gupta ◽  
Cyril J. Donnelly ◽  
Jody L. Jensen ◽  
Jeffrey A. Reinbolt
Keyword(s):  
Injury Prevention ◽  
Shoulder Joint ◽  
Injury Risk ◽  
Performance Enhancement ◽  
Optimization Methods ◽  
Knee Extension ◽  
Peak Height ◽  
Whole Body ◽  
Dynamic Simulations ◽  
Joint Torques

Performance enhancement and injury prevention are often perceived as opposite sides of a coin, where focusing on improvements of one leads to detriment of the other. In this study, we used physics-based simulations with novel optimization methods to find participant-specific, whole-body mechanics of volleyball spiking that enhances performance (the peak height of the hitting hand and its forward velocity) while minimizing injury risk. For the volleyball spiking motion, the shoulder is the most common injury site because of the high mechanical loads that are most pronounced during the follow-through phase of the movement. We analyzed 104 and 209 spiking trials across 13 participants for the power and follow-through phases, respectively. During the power phase, simulations increased (p < 0.025) the peak height of the hitting wrist by 1% and increased (p < 0.025) the forward wrist velocity by 25%, without increasing peak shoulder joint torques, by increasing the lower-limb forward swing (i.e., hip flexion, knee extension). During the follow-through phase, simulations decreased (p < 0.025) peak shoulder joint torques by 75% elicited by synergistic rotation of the trunk along the pathway of the hitting arm. Our results show that performance enhancement and injury prevention are not mutually exclusive and may both be improved simultaneously, potentially leading to better-performing and injury-free athletes.

scholarly journals Are Torque-Driven Simulation Models of Human Movement Limited by an Assumption of Monoarticularity?

2021 ◽  
Vol 11 (9) ◽  
pp. 3852
Author(s):  
Martin G. C. Lewis ◽  
Maurice R. Yeadon ◽  
Mark A. King
Keyword(s):  
Lower Limb ◽  
Simulation Models ◽  
Human Movement ◽  
Joint Torque ◽  
Whole Body ◽  
Countermovement Jump ◽  
Joint Torques ◽  
Large Joint ◽  
Subject Specific ◽  
Similar Accuracy

Subject-specific torque-driven computer simulation models employing single-joint torque generators have successfully simulated various sports movements with a key assumption that the maximal torque exerted at a joint is a function of the kinematics of that joint alone. This study investigates the effect on model accuracy of single-joint or two-joint torque generator representations within whole-body simulations of squat jumping and countermovement jumping. Two eight-segment forward dynamics subject-specific rigid body models with torque generators at five joints are constructed—the first model includes lower limb torques, calculated solely from single-joint torque generators, and the second model includes two-joint torque generators. Both models are used to produce matched simulations to a squat jump and a countermovement jump by varying activation timings to the torque generators in each model. The two-joint torque generator model of squat and countermovement jumps matched measured jump performances more closely (6% and 10% different, respectively) than the single-joint simulation model (10% and 24% different, respectively). Our results show that the two-joint model performed better for squat jumping and the upward phase of the countermovement jump by more closely matching faster joint velocities and achieving comparable amounts of lower limb joint extension. The submaximal descent phase of the countermovement jump was matched with similar accuracy by the two models (9% difference). In conclusion, a two-joint torque generator representation is likely to be more appropriate for simulating dynamic tasks requiring large joint torques and near-maximal joint velocities.

Vision adds to haptics when dyads perform a whole-body joint balance task

2017 ◽  
Vol 235 (7) ◽  
pp. 2089-2102 ◽  
Author(s):  
Eric Eils ◽  
Rouwen Cañal-Bruland ◽  
Leonie Sieverding ◽  
Marc H. E. de Lussanet ◽  
Karen Zentgraf
Keyword(s):  
Whole Body ◽  
Balance Task ◽  
Body Joint

An Upper Limb Exoskeleton for Pinpointed Muscular Exercises With Overextension Injury Prevention

2010 ◽  
Author(s):  
Tzong-Ming Wu ◽  
Shu-Yi Wang ◽  
Dar-Zen Chen
Keyword(s):  
Upper Limb ◽  
Elbow Joint ◽  
Whole Body ◽  
Shoulder Abduction ◽  
Muscle Training ◽  
Joint Torques ◽  
Upper Limb Exoskeleton ◽  
Free Weight ◽  
Flexion Extension ◽  
Muscle Groups

Over-automated equipments and modern city life style lead to the diminishing opportunities for muscle using; however, the comfortable life is not always good for human health, and appropriate muscle training can not only enhance muscular strength and endurance but improve the health and fitness. Different kinds of ideas have been proposed for muscle training by exercise machines, which control direction of resistance for safety sake but isolate specific muscle groups to be trained. Compared with machines, free-weight exercise is a whole-body training in which human limbs can be moved on different planes to train more muscle groups. In this study, an upper limb exoskeleton design is proposed for free-weight exercise to strengthen the principal muscles of upper limb and shoulder. The upper limb exoskeleton is constituted of 3-DOF shoulder joint and 1-DOF elbow joint. The joint torques of shoulder and elbow joint of the exoskeleton match the objective joint torques from a model of free-weight exercise. The principal muscles of human arm and shoulder are training by dumbbell lateral raise, dumbbell frontal raise, dumbbell curl motion, and overhead triceps extension motion. With the arrangement of small-inertia springs, the exoskeleton is capable of preventing the muscle from injuries caused by the huge inertia change. The evaluation of the model was conducted by using isokinetic dynamometer to measure shoulder abduction-adduction, shoulder flexion-extension, and elbow flexion-extension for the male and female adults, and the results matched with the data obtained from the derived model.

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