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Human voluntary movements are complex physical phenomena due to the complex control mechanism for coordination of limbs in the presence of physiological constraints. In this study, we propose a nonlinear human bipedal model with thirteen generalized coordinates to model sit-to-stand (STS) transfer. The model has three position based holonomic const...
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... This novel scheme is more realistic for STS motion for neurologically disabled humans in comparison to earlier techniques, which considered one foot a free foot with 6DoF [6]. Furthermore, in previous studies [7], three position-based and three velocity-based holonomic constraints were included, which makes the system physiologically redundant [8]. In our novel design, we eradicated these physiologically redundant holonomic constraints, which makes design more substantial to human's gait while carrying out STS maneuver. ...
... So for these settlements, a 1DoF prismatic joint is mandatory and is included in the left foot with the base. This innovative scheme is also full rank controllable and observable than the previous design schemes of free foot models of [8]. Furthermore, in the previous schemes [8], six holonomic constraints (three position and three velocity) were included in the system which created redundencies in the model due to complexity of STS. ...
... This innovative scheme is also full rank controllable and observable than the previous design schemes of free foot models of [8]. Furthermore, in the previous schemes [8], six holonomic constraints (three position and three velocity) were included in the system which created redundencies in the model due to complexity of STS. In our model, the kinematic structure of biped is further augmented by eradicating these physiologically redundant holonomic constraints which makes the design more substantial to human's gait while carrying out STS maneuver. ...
The sit-to-stand (STS) model from a biomechanical point of view is an enormously important subject, with motor controls simulating human intended behavior. Physiological motion-based biomechanical research is important for designing whole-body prosthetics and understanding physical disabilities. The control strategies for biomechanical models can effectively synergize with the central nervous system (CNS) to facilitate the desired movements of individuals with neurological disabilities. In this study, we present our novel 3D biped model by decoupling it into healthy and neurologically deficient joints. The developed 8-segment model (i.e., 2x feet, 2x shanks, 2x thighs, 1x pelvic, and 1x Head Arm Torso (HAT) segment) with 10 joints is decoupled into 6 healthy joints and 4 deficient joints. This decoupling mimics stroke patients or subjects with neuromuscular deficiency. This novel decoupling establishes through asymmetrical torques in frontal and sagittal plane joints on a bipedal design with one foot fixed and the other a sliding tilt joint. In this design, two decoupled controllers collaborate to stabilize the nonlinear model for biped STS transfer. Utilizing the xml files from SOLIDWORKS, the model is linearized in SIMSCAPE / SIMULINK. We further imply the Linear Quadratic Regulator (LQR) optimal controller design in MATLAB / SIMULINK for torques in both the sagittal and frontal planes, respectively, for six healthy and four deficient joints. We also comprehend the forward thrust velocity controls to pragmatically model the STS of stroke patients. This decoupling enhanced the overall stability of the system and simulated more relevant angular and velocity profiles for neurologically deficient substances.
... Although standing-up trajectories were synthesized for healthy young subjects and amputees through dynamic optimization, the initial time of the motion was considered to be the seat-off instance. Mughal and Iqbal [43] developed optimal controllers for 3-D STS and studied neuromuscular disorders by decoupling intact and neurodeficient extremities with the reference experimental trajectories. A method to estimate external contact loads with inverse dynamics through optimization during a STS was presented in [44]. ...
Sit-to-stand (STS) motion is one of the most important tasks in daily life and is one of the key determinants of functional independence, especially for the senior people. The STS motion has been extensively studied in the literature, mostly through experiments. Compared to numerous experimental studies, there are limited simulations with mostly assuming bilateral symmetry for STS tasks. However, it is not true even for healthy individuals to perform STS tasks with a perfect bilateral symmetry. In this study, predictive dynamics is utilized for STS prediction. The problem can be constructed as a nonlinear optimization formulation. The digital human model has 21 degrees of freedom (DOFs) for the unassisted STS tasks. The quartic B-spline interpolation is implemented for representing joint angle profiles. The recursive Lagrangian dynamics approach and the Denavit–Hartenberg method are implemented for the equations of motion. This study is to develop a generic three-dimensional unassisted STS motion prediction method for healthy young and elderly individuals. Results show that trunk joint angle peak values are similar between the two virtual-groups in the sagittal, frontal, and transverse planes. Lower-limbs’ joint angle and velocity profiles and their peak values between the right and left side for both virtual groups are also similar. The normalized peak joint torques are slight differences in each active DOF between the two virtual groups and the peak values are similar. The proposed method has been indirectly validated through the literature experimental results. The developed method has various potential applications in the design of exoskeleton, microelectromechanical system for fall detection, and assistive devices in rehabilitation.
... Currently the biomechanical (modelling) community is undecided on which combination of movement objectives (cost-functions) best reproduces movement strategies that ageing humans choose for motor tasks (43,(57)(58)(59). The central nervous system may even apply different weighting for different phases of a complex task (59). ...
To prevent, mitigate and treat movement impairments, we need to recognize early signs of decline and understand how to best compensate for limitations. The mechanisms leading to movement impairments are complex, overlapping, and interdependent and the fields of biomechanics, motor control, and physiology must be combined to understand these mechanisms. This article introduces CaReMoOC, a framework incorporating neuromusculoskeletal capacity (accumulation of neuromusculoskeletal resources over the lifespan), reserve (task-specific difference between capacity and task demand), movement objectives (considerations made to plan a movement), and compensation (use of NMSK resources to respond to the task demand). The framework is demonstrated for healthy ageing, providing an overview of age-related capacity decline (neural, skeletal, muscular system) and shifted weighting of movement objectives (energy, pain, stability, speed) relevant for biomechanics and motor control. Two forms of compensation are Compensation for Capacity, when capacity does not meet the task demands, and Compensation for Movement Objectives, when the movement is changed due to for example a fear of falling. Understanding the interrelationships between decline in the variables within capacity and the effect on compensation strategies will provide benefit in preventing mobility impairments and will support clinicians in their rehabilitation practice.
... The first use of a spatial model was found in [31], where the five-link 3D model was utilized in an OBMG method. Later on in [32], [33] and [16] the eight-link 3D model is used in a CBMG where a LQR is proposed. Recently the 9-link 3D model is used in [5] again with a OBMG. ...
... A mathematical model that describes the K&D of the multilink system that represents the human body is necessary, this model is known as the equation of motion. The equation of motion may be obtained by using a specialized software such as in [32] and in [16] or it may be obtained analytically by applying different approaches, such as Lagrangian dynamics, Newton's laws or more recently recursive dynamics [34], which is a convenient approach when large DoF systems are considered. The equations obtained by the afore mentioned approaches are usually expressed in the Euler-Lagrange formulation: ...
... The reference is generated by a linear system similar to (5) but with matrix A * ∈ R 10x10 . The same model and methodology is used in [16] but the decoupling procedure is used to separate frontal variables from sagittal variables. The tracking of the imposed reference results better than [32] but torques settle at zero in both works. ...
Human-like motion prediction and simulation is an important task with many applications in fields such as occupational-biomechanics, ergonomics in industrial engineering, study of biomechanical systems, prevention of musculoskeletal disorders, computer-graphics animation of articulated figures, prosthesis and exoskeletons design as well as design and control of humanoid robots, among others.
In an effort to get biomechanical insight in many human movements, extensive work has been conducted over the last decades on human-motion prediction of tasks as: walking, running, jumping, standing from a chair, reaching and lifting. This literature review is focused on the STS motion and the LLM. STS is defined as the process of rising from a chair to standing up position without losing stability balance, it is the most ubiquitous and torque-demanding daily labor and it is closely related to other capabilities of the human body. LLM is defined as the activity of raising a load, generally a box, from a low to a higher position while stability is maintained, this task produces a high number of incidences of low-back pain and injuries in many industrial and domestic activities.
In order to predict STS and LLM, two methods have been identified: these are the OBMG method and the CBMG method.
... Moreover, Oğuztöreli and Stein [15] have used a similar linear model to study various cost functions considering an antagonistic muscle. There are some other works on optimal control or dynamic optimization of the lower limbs to predict the human walking [16,17], pedaling [18] and sit to stand [19] motions. ...
... In this modified method, the previously mentioned iterative procedure of the VE algorithm (Eqs. (19) to (22) ...
In this paper, the optimal performance of a planar humanlike musculoskeletal arm is investigated during reaching movements employing an optimal control policy. The initial and final states (position and velocity) are the only known data of the response trajectory. Two biomechanical objective functions are taken into account to be minimized as the central nervous system (CNS) strategy: (1) a quadratic function of muscle stresses (or forces), (2) total time of movement plus a quadratic function of muscle stresses. A two-degress of freedom (DOF) nonlinear musculoskeletal arm model (for planar movements) with six muscle actuators and four state variables is used in order to evaluate the proposed optimal policy, while the constraints of the arm motion and muscle forces are considered mathematically. The nonlinear differential equations of this optimal control problem with the first objective function are solved using the method of variation of extremals (VE). For the second objective function, a modified version of the VE method is employed. Accordingly, the optimal total time of the motion is predicted via the second objective function in addition to the optimal trajectory and forces that are also predicted using the first objective function. The influence of the motion time duration on the optimal trajectory is shown and discussed. Finally, the obtained optimal trajectories are compared to the experimental trajectories of the human arm movements.
... Thus, the weight transfer from the chair to the ground phase was not considered in the analysis. Mughal and Iqbal [23] designed optimal controllers for the 3-D STS maneuver and studied neuromuscular disorders by decoupling intact and neurodeficient extremities with the usage of reference experimental trajectories. A method to estimate external contact loads with inverse dynamics through optimization during a STS maneuver was presented in [24]. ...
Sit-to-stand (STS) is a common activity in daily lives which requires relatively high joint torques and a robust coordination of lower and upper extremities with postural stability. Many elderly, people with lower limb injuries, and patients with neurological disorders or musculoskeletal abnormalities have difficulties in accomplishing this task. In contrast to the literature on numerous experimental studies of STS, there are limited studies that were carried out through simulations. In literature, mostly bilateral symmetry was assumed for STS tasks, however even for healthy people, it is more difficult to perform STS tasks with a perfect bilateral symmetry. The goal of this research is to develop a three-dimensional unassisted STS motion prediction formulation for healthy young individuals. Predicted results will be compared with experimental results found in literature for the validation of the proposed formulation.
Copyright © 2014 by ASME Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
... The major purpose of this study was to develop a procedure to validate biomechanical models for the STS task. We compared the experimental profiles of GRF for STS movement with analytically obtained solutions in [4] and with synthesized data in [5]. We obtained plots of GRF in vertical y-direction and moments along x and z-directions, where distance between the feet represented in x-axis and foot length is in zaxis. ...
... However, these models can still be validated through indirect means by obtaining results of measureable kinematic and kinetic variables such as GRF and moments. These results shows the applicability of modeling schemes presented in [4][5] for analyses and techniques related to STS movement. ...
