Bioaeroservoelastic Analysis of Involuntary Rotorcraft-Pilot Interaction

2014 ◽  
Vol 9 (3) ◽  
Author(s):  
Pierangelo Masarati ◽  
Giuseppe Quaranta
Keyword(s):  
Muscle Activation ◽  
Inverse Dynamics ◽  
Transfer Functions ◽  
Biomechanical Model ◽  
Coupled System ◽  
Multibody Modeling ◽  
Activation Patterns ◽  
Pilot Model ◽  
The Stability ◽  
Muscular Activation

This work presents the integration of a detailed biomechanical model of the arm of a helicopter pilot and an equivalently detailed aeroservoelastic model of a helicopter, resulting in what has been called a ‘bioaeroservoelastic’ analysis. The purpose of this analysis is to investigate potential adverse interactions, called rotorcraft-pilot couplings, between the aeroservoelastic system and the controls involuntarily introduced by the pilot into the control system in response to rotorcraft vibrations transmitted to the pilot through the cockpit: the so-called biodynamic feedthrough. The force exerted by the pilot on the controls results from the activation of the muscles of the arms according to specific patterns. The reference muscular activation value as a function of the prescribed action on the controls is computed using an inverse kinetostatics/inverse dynamics approach. A first-order quasi-steady correction is adopted to mimic the reflexive contribution to muscle activation. Muscular activation is further augmented by activation patterns that produce elementary actions on the control inceptors. These muscular activation patterns, inferred using perturbation analysis, are applied to control the aircraft through the pilot's limbs. The resulting biomechanical pilot model is applied to the aeroservoelastic analysis of a helicopter model expressly developed within the same multibody modeling environment to investigate adverse rotorcraft pilot couplings. The model consists of the detailed aeroelastic model of the main rotor, using nonlinear beams and blade element/momentum theory aerodynamics, a component mode synthesis model of the airframe structural dynamics, and servoactuator dynamics. Results in terms of the stability analysis of the coupled system are presented in comparison with analogous results obtained using biodynamic feedthrough transfer functions identified from experimental data.

Coupled Bioaeroservoelastic Rotorcraft-Pilot Simulation

2013 ◽  
Author(s):  
Pierangelo Masarati ◽  
Giuseppe Quaranta
Keyword(s):  
Muscle Activation ◽  
Inverse Dynamics ◽  
Transfer Functions ◽  
Biomechanical Model ◽  
Coupled System ◽  
Multibody Modeling ◽  
Activation Patterns ◽  
Pilot Model ◽  
Aeroelastic Model ◽  
Muscular Activation

This work presents the integration of a detailed biomechanical model of the arms of a helicopter pilot and an equivalently detailed aeroservoelastic model of a helicopter, resulting in what has been called a ‘bioaeroservoelastic’ analysis. The purpose is to investigate potential adverse interactions, called rotorcraft-pilot couplings, between the aeroservoelastic system and the controls involuntarily introduced by the pilot into the control system in response to rotorcraft vibrations transmitted to the pilot through the cockpit, the so-called biodynamic feedthrough. The force exerted by the pilot on the controls results from the activation of the muscles of the arms according to specific patterns. The reference muscular activation value as a function of the prescribed action on the controls is computed using an inverse kinetostatics/inverse dynamics approach. A first-order quasi-steady correction is adopted to mimic the reflexive contribution to muscle activation. Muscular activation is further augmented by activation patterns that produce elementary actions on the control inceptors. These muscular activation patterns, inferred using perturbation analysis, are applied to control the aircraft through the pilot’s limbs. The resulting biomechanical pilot model is applied to the aeroservoelastic analysis of a helicopter model expressly developed within the same multibody modeling environment to investigate adverse rotorcraft pilot couplings. The model consists of the detailed aeroelastic model of the main rotor, using nonlinear beams and blade element/momentum theory aerodynamics, a component mode synthesis model of the airframe structural dynamics, and servoactuator dynamics. Results in terms of stability analysis of the coupled system are presented in comparison with analogous results obtained using biodynamic feedthrough transfer functions identified from experimental data.

Rotorcraft Pilot Impedance From Inverse Dynamics-Based Biomechanical Model

2012 ◽  
Author(s):  
Andrea Zanoni ◽  
Giuseppe Quaranta ◽  
Pierangelo Masarati
Keyword(s):  
Inverse Dynamics ◽  
Biomechanical Model ◽  
Biomechanical Properties ◽  
Activation Patterns ◽  
Joint Torques ◽  
Multibody Model ◽  
Equivalent Impedance ◽  
Helicopter Pilots ◽  
Machine Interface ◽  
Muscular Activation

The involuntary interaction of the pilot with a vehicle is often an undesired consequence of the biomechanical properties of the human body and its relation with the layout of the man-machine interface. This work discusses how muscular activation patterns affect the variability of the equivalent impedance of helicopter pilots. A multibody model is used to compute the joint torques associated to a prescribed pilot task, which are then transformed into corresponding ‘optimal’ muscular activation patterns. Equivalent pilot impedance is obtained by consistently linearizing the constitutive model of the muscles about the reference activation. The effect on equivalent impedance of non-optimal activation, resulting from the addition of Torque-Less Activation Modes to the optimal activation, is evaluated and discussed.

Estimation of Muscle Forces About the Ankle During Gait in Healthy and Neurologically Impaired Subjects

2011 ◽  
pp. 320-347
Author(s):  
Daniel N. Bassett ◽  
Joseph D. Gardinier ◽  
Kurt T. Manal ◽  
Thomas S. Buchanan
Keyword(s):  
Muscle Activation ◽  
Inverse Dynamics ◽  
Biomechanical Model ◽  
Forward Dynamics ◽  
Muscle Forces ◽  
Dynamics Model ◽  
Joint Moments ◽  
Neurologically Impaired ◽  
Model Predictions ◽  
Contraction Dynamics

This chapter describes a biomechanical model of the forces about the ankle joint applicable to both unimpaired and neurologically impaired subjects. EMGs and joint kinematics are used as inputs and muscle forces are the outputs. A hybrid modeling approach that uses both forward and inverse dynamics is employed and physiological parameters for the model are tuned for each subject using optimization procedures. The forward dynamics part of the model takes muscle activation and uses Hill-type models of muscle contraction dynamics to estimate muscle forces and the corresponding joint moments. Inverse dynamics is used to calibrate the forward dynamics model predictions of joint moments. In this chapter we will describe how to implement an EMG-driven hybrid forward and inverse dynamics model of the ankle that can be used in healthy and neurologically impaired people.

scholarly journals Experiment and Analysis of Active Vibration Suppression via an Absorber with a Tunable Delay

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yixia Sun
Keyword(s):  
Vibration Suppression ◽  
Transfer Functions ◽  
Experimental Studies ◽  
Coupled System ◽  
Gain Coefficient ◽  
Feedback Gain ◽  
Primary System ◽  
Active Vibration ◽  
The Stability ◽  
Proper Values

A time-delayed absorber is utilized to suppress the vibration of a primary system excited by a simple harmonic force. The inherent and intentional time delays in the feedback control loop are taken into consideration. The value of the former is fixed, while the value of the latter is tunable in the controller. To begin with, the mechanical model of the system is established and the acceleration transfer functions of the system are derived. Consequently, the stability analysis of the coupled system is carried out. Finally, the experimental studies on the performance of the time-delayed absorber are conducted. Both experimental and theoretical results show that the time-delayed absorber with proper values of feedback gain coefficient and intentional time delay greatly suppresses the vibration of the primary system. The numerical results validate the correctness of the experimental and theoretical ones.

EMG-Assisted Neuromusculoskeletal Models Can Estimate Physiological Muscle Activations and Joint Moments Across the Neck Before Impacts

2021 ◽  
Author(s):  
Pavlos Silvestros ◽  
Claudio Pizzolato ◽  
David G. Lloyd ◽  
Ezio Preatoni ◽  
Harinderjit S. Gill ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Muscle Activation ◽  
Inverse Dynamics ◽  
A Priori ◽  
Neck Muscle ◽  
Joint Moments ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Flexion Extension ◽  
Muscle Activations

Abstract Knowledge of neck muscle activation strategies prior to sporting impacts is crucial for investigating mechanisms of severe spinal injuries. However, measurement of muscle activations during impacts is experimentally challenging and computational estimations are not often guided by experimental measurements. We investigated neck muscle activations prior to impacts with the use of electromyography (EMG)-assisted neuromusculoskeletal models. Kinematics and EMG recordings from four major neck muscles of a rugby player were experimentally measured during rugby activities. A subject-specific musculoskeletal model was created with muscle parameters informed from MRI measurements. The model was used in the Calibrated EMG-Informed Neuromusculoskeletal Modelling toolbox and three neural solutions were compared: i) static optimisation (SO), ii) EMG-assisted (EMGa) and iii) MRI-informed EMG-assisted (EMGaMRI). EMGaMRI and EMGa significantly (p¡0.01) outperformed SO when tracking cervical spine net joint moments from inverse dynamics in flexion/extension (RMSE = 0.95, 1.14 and 2.32 Nm) but not in lateral bending (RMSE = 1.07, 2.07 and 0.84 Nm). EMG-assisted solutions generated physiological muscle activation patterns and maintained experimental co-contractions significantly (p¡0.01) outperforming SO, which was characterised by saturation and non-physiological "on-off" patterns. This study showed for the first time that physiological neck muscle activations and cervical spine net joint moments can be estimated without assumed a priori objective criteria prior to impacts. Future studies could use this technique to provide detailed initial loading conditions for theoretical simulations of neck injury during impacts.

Stability of Stepping Movements in the Frontal Plain: A Biomechanical Model

2007 ◽  
Author(s):  
Sonja A. Karg
Keyword(s):  
Muscle Activation ◽  
Biomechanical Model ◽  
Pattern Generator ◽  
Neural Oscillator ◽  
Complex Task ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Oscillator Network ◽  
Stepping In Place ◽  
Basic Movement

Walking is a complex task influenced by many factors. It is still not well understood how single parts as mechanics, sensor feedback and according control components are integrated to the very robust and adaptive task ‘walking’. So one possible way to address this task is to look at single components, as passive mechanics, and analyze their abilities for walking [1,2]. Or rhythmic movement mechanisms in vertebrates are analyzed, like central pattern generator mechanisms, to produce muscle activation patterns [3]. The combination of mechanics and rhythmic actuation leads to more robust walkers [4]. In the following a new biomechanical model for stepping movements in the frontal plain is introduced. This model bases on passive dynamics actuated by a neural oscillator network. It concentrates on low level generation of basic movement patterns which allow different stepping tasks as stepping in place, stepping up and down or stepping to the side. For the case stepping in place, it is shown that there exist periodic movements which are stable in the sense of a limit cycle, though the movement is varied in frequency and amplitude.

Estimation of Corrective Changes in Muscle Activation Patterns for Stroke Patients During FES Intervention

2007 ◽  
Author(s):  
Qi Shao ◽  
Daniel N. Bassett ◽  
Kurt Manal ◽  
Thomas S. Buchanan
Keyword(s):  
Electrical Stimulation ◽  
Muscle Activation ◽  
Control Strategies ◽  
Biomechanical Model ◽  
Stroke Patients ◽  
Activation Patterns ◽  
Know How ◽  
Muscle Activation Patterns ◽  
Person Following ◽  
Human Movements

Functional electrical stimulation (FES) has been used in the rehabilitation of stroke patients. It is important to know how to stimulate the muscles when using FES. Many control methods have been used to derive the required electrical stimulation patterns. However, these models were not developed based on biomechanical model of human neuromuscular system, thus can not account for sophisticated neurological control strategies during human movements. Based on our developed electromyography (EMG) driven model, we have created a biomechanical model to estimate the corrective increases in muscle activation patterns needed for a person following stroke to walk with an improved normal gait.

Trajectory Planning of Spine Motion During Flexion Using a Stability-Based Optimization

2010 ◽  
Author(s):  
Majid Khorsand Vakilzadeh ◽  
Hassan Salarieh ◽  
Mohsen Asghari ◽  
Mohamad Parnianpour
Keyword(s):  
Degrees Of Freedom ◽  
Muscle Activation ◽  
Inverse Dynamics ◽  
Joint Stiffness ◽  
Static Stability ◽  
Computational Method ◽  
Muscle Activation Patterns ◽  
Spine Motion ◽  
The Stability ◽  
The Many

A central problem in motor control is to understand how the many biomechanical degrees of freedom are coordinated to achieve a goal. A common assumption is that Central Nervous System (CNS) would minimize a performance index to achieve this goal which is called objective function. In this paper, two popular objective functions are utilized to design the optimal trajectory of trunk movements. A 3D computational method incorporated with 18 anatomically oriented muscles is used to simulate human trunk system. Inverse dynamics allows us to compute torque which is generated around Lumbosacral joint. This torque is divided among muscles by static stability-based optimization. Trunk movement from the upright standing to 30 degrees of flexion is simulated based on this method. Incorporation of the stability condition with the static optimization resulted in an increase of antagonistic activities which would increase the joint stiffness around the Lumbosacral joint in response to gravity perturbation. Results would shed light on the interaction mechanisms in muscle activation patterns, seen in various performance indices.

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