Dynamic Walking Research Articles

Design of a Quasi-Passive Dynamic Walking Robot Based on Anatomy Trains Theory

Design of a Quasi-Passive Dynamic Walking Robot Based on Anatomy Trains Theory

Dynamic Random Walk and Dynamic Opposition Learning for Improving Aquila Optimizer: Solving Constrained Engineering Design Problems.

One of the most important tasks in handling real-world global optimization problems is to achieve a balance between exploration and exploitation in any nature-inspired optimization method. As a result, the search agents of an algorithm constantly strive to investigate the unexplored regions of a search space. Aquila Optimizer (AO) is a recent addition to the field of metaheuristics that finds the solution to an optimization problem using the hunting behavior of Aquila. However, in some cases, AO skips the true solutions and is trapped at sub-optimal solutions. These problems lead to premature convergence (stagnation), which is harmful in determining the global optima. Therefore, to solve the above-mentioned problem, the present study aims to establish comparatively better synergy between exploration and exploitation and to escape from local stagnation in AO. In this direction, firstly, the exploration ability of AO is improved by integrating Dynamic Random Walk (DRW), and, secondly, the balance between exploration and exploitation is maintained through Dynamic Oppositional Learning (DOL). Due to its dynamic search space and low complexity, the DOL-inspired DRW technique is more computationally efficient and has higher exploration potential for convergence to the best optimum. This allows the algorithm to be improved even further and prevents premature convergence. The proposed algorithm is named DAO. A well-known set of CEC2017 and CEC2019 benchmark functions as well as three engineering problems are used for the performance evaluation. The superior ability of the proposed DAO is demonstrated by the examination of the numerical data produced and its comparison with existing metaheuristic algorithms.

Functional analysis of postural spinal and pelvic parameters using static and dynamic spinometry

BackgroundSpinometry is a radiation-free method to three-dimensional spine imaging that provides additional information about the functional gait patterns related to the pelvis and lower extremities. This radiation-free technology uses the surface topography of the trunk to analyze surface asymmetry and identify bony landmarks, thereby aiding the assessment of spinal deformity and supporting long-term treatment regimes. Especially reliable dynamic spinometric data for spine and pelvis are necessary to evaluate the management of non-specific back pain. Research aimThis study aims to generate reliable dynamic spinometric data for spine and pelvis parameters that can serve as reference data for future studies and clinical practice. MethodsThis study assessed 366 subjects (185 females) under static and 360 subjects (181 females) under dynamic (walking on a treadmill at 3 km/h and 5 km/h) conditions. The DIERS Formetric 4Dmotion® system uses stripes of light to detect the surface topography of the spine and pelvis and identifies specific landmarks to analyze the spine during standing and walking. ResultsRelevant gender effects were calculated for lordotic angle (ηp2 = 0.22) and pelvic inclination (ηp2 = 0.26). Under static conditions, female subjects showed larger values for both parameters (lordotic angle: 41.6 ± 8.60°; pelvic inclination: 25.5 ± 7.49°). Regarding speed effects, three relevant changes were observed (sagittal imbalance: ηp2 = 0.74, kyphotic angle: ηp2 = 0.13, apical deviation: ηp2 = 0.11). The most considerable changes were observed between static condition and 3 km/h, especially for sagittal imbalance and lordotic angle. For these parameters, relevant effect sizes (d > 0.8) were calculated between static and 3 km/h for males and females. Concerning clinical vertebral parameters, only lordotic angle and pelvic inclination were correlated with each other (r = 0.722). ConclusionThis study generated a gender-specific reference database of asymptomatic individuals for static and dynamic spinometry. It demonstrated that the DIERS Formetric 4Dmotion® system could capture natural changes in static and dynamic situations and catalogue functional adaptations of spino-pelvic statics at different speeds. The lordotic angle is an indirect marker of pelvic inclination, allowing spinometry to identify individuals at risk even under dynamic conditions.

Enhanced prairie dog optimization with Levy flight and dynamic opposition-based learning for global optimization and engineering design problems

This study proposes a new prairie dog optimization algorithm version called EPDO. This new version aims to address the issues of premature convergence and slow convergence that were observed in the original PDO algorithm. To improve performance, several modifications are introduced in EPDO. First, a dynamic opposite learning strategy is employed to increase the diversity of the population and prevent premature convergence. This strategy helps the algorithm avoid falling into local optima and promotes global optimization. Additionally, the Lévy dynamic random walk technique is utilized in EPDO. This modified Lévy flight with random walk reduces the algorithm’s running time for the test function’s ideal value, accelerating its convergence. The proposed approach is evaluated using 33 benchmark problems from CEC 2017 and compared against seven other comparative techniques: GWO, MFO, ALO, WOA, DA, SCA, and RSA. Numerical results demonstrate that EPDO produces good outcomes and performs well in solving benchmark problems. To further validate the results and assess reliability, the authors employ average rank tests, the measurement of alternatives, and ranking according to the compromise solution (MARCOS) method, as well as a convergence report of EPDO and other algorithms. Furthermore, the effectiveness of the EPDO algorithm is demonstrated by applying it to five design problems. The results indicate that EPDO achieves impressive outcomes and proves its capability to address practical issues. The algorithm performs well in solving benchmark and practical design problems, as supported by the numerical results and validation methods used in the study.

Effectiveness of Wii-Fit Combined with Conventional Exercises on the Functional Mobility and Balance of Children with Cerebral Palsy and Their Typically Growing Peers.

Nintendo Wii Fit is an accessible, affordable, and productive inclusion into rehabilitation programs for children with cerebral palsy (CP) as a physical activity intervention; however, to our knowledge, there are no comparative studies 8 investigating the effects on the functional mobility and balance of children with CP compared to typically growing (TG) children. We evaluated the effects of Nintendo Wii Fit video exercises on static and dynamic balance, functional capacity, and walking endurance in children with CP compared to their TG peers. Children with CP and their TG peers were trained with Nintendo Wii Fit Balance Board games and conventional exercises (40 minutes each) for 16 weeks, twice a week. Their static and dynamic balance, functional capacity, and walking endurance were evaluated at the beginning and end of the study. The improvement achieved within the groups in all parameters, as well as between the groups, was significant, except for the dynamic balance and walking endurance. Standing Nintendo Wii Fit exercises combined with conventional exercises can be included as axial exercises in the physiotherapy program for children with CP as an enjoyable physical activity. TG children may also benefit, increasing their functional mobility and walking endurance in a fun way.

A Low-Inertia and High-Stiffness Cable-Driven Biped Robot: Design, Modeling, and Control

In this paper, a biped robot system for dynamic walking is presented. It has two 2-degree-of-freedom (DOF) lightweight legs and a 6-DOF hip. All the joint pulleys of the legs are driven by motors that are placed at the hip using steel cables. Since all the heavy motors are mounted at the hip, the biped robot has remarkably low-mass legs beyond the hip, which guarantees low inertia during walking at high speeds. Utilizing cable-amplification mechanisms, high stiffness and strength are achieved, resulting in better control performance compared to conventional direct-driven methods. Techniques are developed to estimate joint-angle errors caused by the elastic deformation of the cables. To achieve smooth control, we introduce the concept of a virtual leg, which is an imaginary leg connecting the hip joint and the ankle joint. A robust control approach based on the “virtual leg” is presented, which considers the variances of the virtual leg length during walking. Experiments are conducted to validate the effectiveness of the mechanical design and the proposed control approach.

Efficacy of functional electrical stimulation of the lower extremities in stroke patients

Aim. To evaluate the efficacy of functional electrical stimulation of the lower extremities in stroke patients at different stages of motor rehabilitation.Materials and methods. The study involved 80 patients with motor disorders after stroke. The studied treatment methods included passive and passive-active functional electrical stimulation (FES) in combination with the THERATrainer Tigo and active FES (neuro-orthosis) WalkAide.Results. The analysis of motor status indicators, namely the Berg Balance Scale, 6-minute walk test, and dynamic walking index showed the maximum efficacy of active FES with biofeedback.Conclusion. When prescribing and selecting a method of electrical stimulation, preference in neurorehabilitation should be given to methods of passive-active and active functional stimulation.

Silver-Coordinated Watson-Crick Pairing-Driven Three-Dimensional DNA Walker for Locus-Specific Detection of Genomic N6-Methyladenine and N4-Methylcytosine at the Single-Molecule Level.

N6-Methyladenine (6mdA) and N4-methylcytosine (4mdC) are the two most dominant DNA modifications in both prokaryotes and eukaryotes, but standard hybridization-based techniques cannot be applied for the 6mdA/4mdC assay. Herein, we demonstrate the silver-coordinated Watson-Crick pairing-driven three-dimensional (3D) DNA walker for locus-specific detection of genomic 6mdA/4mdC at the single-molecule level. 6mdA-DNA and 4mdC-DNA can selectively hybridize with the binding probes (BP1 and BP2) to form 6mdA-DNA-BP1 and 4mdC-DNA-BP2 duplexes. The 6mdA-C/4mdC-A mismatches cannot be stabilized by AgI, and thus, 18-nt BP1/BP2 cannot be extended by the catalysis of KF exonuclease. Through toehold-mediated strand displacement (TMSD), the signal probe (SP1/SP2) functionalized on the gold nanoparticles (AuNPs) can competitively bind to BP1/BP2 in 6mdA-DNA-BP1/4mdC-DNA-BP2 duplex to obtain SP1-18-nt BP1 and SP2-18-nt BP2 duplexes. The resulting DNA duplexes can act as the substrates of lambda exonuclease, leading to the cleavage of SP1/SP2 and the release of Cy3/Cy5 and 18-nt BP1/BP2. The released 18-nt BP1/BP2 can subsequently serve as the walker DNA, moving along the surface of the AuNP to activate dynamic 3D DNA walking and releasing abundant Cy3/Cy5. The released Cy3/Cy5 can be quantified by single-molecule imaging. This nanosensor exhibits high sensitivity with a limit of detection (LOD) of 9.80 × 10-15 M for 6mdA-DNA and 9.97 × 10-15 M for 4mdC-DNA. It can discriminate 6mdA-/4mdC-DNA from unmodified genomic DNAs, distinguish 0.01% 6mdA-/4mdC-DNA from excess unmethylated DNAs, and quantify 6mdA-/4mdC-DNA at specific sites in genomic DNAs of liver cancer cells and Escherichia coli plasmid cloning vector, providing a new platform for locus-specific analysis of 6mdA/4mdC in genomic DNAs.

On the Stability of a 3DOF Vibrating System Close to Resonances

Abstract Purpose In the current work, the motion of a three degrees-of-freedom (DOF) dynamical system as a vibrating model is examined. The proposed system is of high importance in vibration engineering applications, such as the analysis of the control of flexible arm robotics, flexible arm vibrational motion as a dynamic system, pump compressors, transportation devices, rotor dynamics, shipboard cranes, and human or walking analysis robotics. Methods Lagrange's equations (LE) are used to derive the equations of motion of the controlling system. The analytic solutions (AS) are obtained utilizing the multiple-scales method (MSM) up to the third order. Results The framework for removing secular terms provides the requirements for the solvability of this problem. Various resonance scenarios are categorized and the modulation equations (ME) are constructed. To graphically demonstrate the beneficial impacts of the distinct parameters of the problem, the time histories (TH) of the approximate solutions as well as the resonance curves (RC) are depicted. The Runge-Kutta algorithm (RKA) is employed to obtain the numerical solutions (NS) of the regulating system. Conclusion A comparison of the AS and NS reveals the accuracy of the perturbation approach. The stability/instability zones are studied using Routh-Hurwitz criteria (RHC), and then they are examined using a steady-state situation. Basically, the used perturbation method is considered a traditional method that is applied to solve a new dynamical system. Then, the achieved results are considered new because they weren’t obtained previously, which indicates the novelty of this work.

High-statistics pedestrian dynamics on stairways and their probabilistic fundamental diagrams

Staircases play an essential role in crowd dynamics, allowing pedestrians to flow across large multi-level public facilities such as transportation hubs, shopping malls, and office buildings. Achieving a robust quantitative understanding of pedestrian behavior in these facilities is a key societal necessity. What makes this an outstanding scientific challenge is the extreme randomness intrinsic to pedestrian behavior. Any quantitative understanding necessarily needs to be probabilistic, including average dynamics and fluctuations. To this purpose, large-scale, real-life trajectory datasets are paramount.In this work, we analyze the data from an unprecedentedly high statistics year-long pedestrian tracking campaign, in which we anonymously collected millions of trajectories of pedestrians ascending and descending stairs within Eindhoven Central train station (The Netherlands). This has been possible thanks to a state-of-the-art, faster than real-time, computer vision approach hinged on 3D depth imaging, sensor fusion, and YOLOv7-based depth localization. We consider both free-stream conditions, i.e. pedestrians walking in undisturbed, and trafficked conditions, unidirectional/bidirectional flows. We report on Eulerian fields (density, velocity and acceleration), showing how the walking dynamics changes when transitioning from stairs to landing. We then investigate the (mutual) positions of pedestrian as density changes, considering the crowd as a “compressible” physical medium. In particular, we show how pedestrians willingly opt to occupy fewer space than available, accepting a certain degree of compressibility. This is a non-trivial physical feature of pedestrian dynamics and we introduce a novel way to quantify this effect. As density increases, pedestrians strive to keep a minimum distance d≈0.6m (two treads of the staircase) from the person in front of them. Finally, we establish first-of-kind fully resolved probabilistic fundamental diagrams, where we model the pedestrian walking velocity as a mixture of a slow and fast-paced component (both in non-negligible percentages and with density-dependent characteristic fluctuations). Notably, averages and modes of velocity distribution turn out to be substantially different. Our results, of which we include probabilistic parametrizations based on few variables, are key towards improved facility design and realistic simulation of pedestrians on staircases.

Stories of QRIO and PINO, and Beyond: Lessons Learned from Small Humanoid Projects From R&D to Business

In 1997, Sony announced AIBO, a fully autonomous small quadruped robot for home entertainment, and in 1999 the company began selling it as a consumer product. Soon after development, two small humanoid robots were announced. One was QRIO by Sony, which is about 60[Formula: see text]cm height body with dynamical bipedal walking and whole-body cooperative control. The other was PINO by the ERATO Kitano Symbiotic Systems Project, which is about 70[Formula: see text]cm height body, Open HW/SW with inexpensive off-the-shelf component. In this paper, we revisit the two humanoids and nearly 20-year-old technologies, and discuss what were done 20 years ago, what have been achieved and what challenges are ahead.

Effects of activity-oriented physiotherapy with and without eye movement training on dynamic balance, functional mobility, and eye movements in patients with Parkinson's disease: An assessor-blinded randomised controlled pilot trial.

To describe changes in balance, walking speed, functional mobility, and eye movements following an activity-oriented physiotherapy (AOPT) or its combination with eye movement training (AOPT-E) in patients with Parkinson's disease (PD). To explore the feasibility of a full-scale randomised controlled trial (RCT). Using an assessor-blinded pilot RCT, 25 patients with PD were allocated to either AOPT or AOPT-E. Supervised interventions were performed 30 minutes, 4x/weekly, for 4 weeks, alongside inpatient rehabilitation. Outcomes were assessed at baseline and post-intervention, including dynamic balance, walking speed, functional and dual-task mobility, ability to safely balance, health-related quality of life (HRQoL), depression, and eye movements (number/duration of fixations) using a mobile eye tracker. Freezing of gait (FOG), and falls-related self-efficacy were assessed at baseline, post-intervention, and 4-week follow-up. Effect sizes of 0.10 were considered weak, 0.30 moderate, and ≥0.50 strong. Feasibility was assessed using predefined criteria: recruitment, retention and adherence rates, adverse events, falls, and post-intervention acceptability using qualitative interviews. Improvements were observed in dynamic balance (effect size r = 0.216-0.427), walking speed (r = 0.165), functional and dual-task mobility (r = 0.306-0.413), ability to safely balance (r = 0.247), HRQoL (r = 0.024-0.650), and depression (r = 0.403). Falls-related self-efficacy (r = 0.621) and FOG (r = 0.248) showed varied improvements, partly sustained at follow-up. Eye movement improvements were observed after AOPT-E only. Feasibility analysis revealed that recruitment was below target, with less than two patients recruited per month due to COVID-19 restrictions. Feasibility targets were met, with a retention rate of 96% (95% confidence interval [CI]: 77.68-99.79) and a 98.18% (95% CI: 96.12-99.20) adherence rate, exceeding the targets of 80% and 75%, respectively. One adverse event unrelated to the study intervention confirmed intervention safety, and interview data indicated high intervention acceptability. AOPT-E and AOPT appeared to be effective in patients with PD. Feasibility of a larger RCT was confirmed and is needed to validate results.

Towards Humanlike Passive Dynamic Walking with Physical and Dynamic Gait Resemblance

Towards Humanlike Passive Dynamic Walking with Physical and Dynamic Gait Resemblance

Analysis of Velocity Variation during Collision for Passive Dynamic Walking via Non-elastic and Elastic Models

Analysis of Velocity Variation during Collision for Passive Dynamic Walking via Non-elastic and Elastic Models

Center of Mass Estimation for Impaired Gait Assessment Using Inertial Measurement Units.

Injury or disease often compromise walking dynamics and negatively impact quality of life and independence. Assessing methods to restore or improve pathological gait can be expedited by examining a global parameter that reflects overall musculoskeletal control. Center of mass (CoM) kinematics follow well-defined trajectories during unimpaired gait, and change predictably with various gait pathologies. We propose a method to estimate CoM trajectories from inertial measurement units (IMUs) using a bidirectional Long Short-Term Memory neural network to evaluate rehabilitation interventions and outcomes. Five non-disabled volunteers participated in a single session of various dynamic walking trials with IMUs mounted on various body segments. A neural network trained with data from four of the five volunteers through a leave-one-subject out cross validation estimated the CoM with average root mean square errors (RMSEs) of 1.44cm, 1.15cm, and 0.40cm in the mediolateral (ML), anteroposterior (AP), and inferior/superior (IS) directions respectively. The impact of number and location of IMUs on network prediction accuracy was determined via principal component analysis. Comparing across all configurations, three to five IMUs located on the legs and medial trunk were the most promising reduced sensor sets for achieving CoM estimates suitable for outcome assessment. Lastly, the networks were tested on data from an individual with hemiparesis with the greatest error increase in the ML direction, which could stem from asymmetric gait. These results provide a framework for assessing gait deviations after disease or injury and evaluating rehabilitation interventions intended to normalize gait pathologies.

Neural correlates of motor imagery and execution in real-world dynamic behavior: evidence for similarities and differences.

A large body of evidence shows that motor imagery and action execution behaviors result from overlapping neural substrates, even in the absence of overt movement during motor imagery. To date it is unclear how neural activations in motor imagery and execution compare for naturalistic whole-body movements, such as walking. Neuroimaging studies have not directly compared imagery and execution during dynamic walking movements. Here we recorded brain activation with mobile EEG during walking compared to during imagery of walking, with mental counting as a control condition. We asked 24 healthy participants to either walk six steps on a path, imagine taking six steps, or mentally count from one to six. We found beta and alpha power modulation during motor imagery resembling action execution patterns; a correspondence not found performing the control task of mental counting. Neural overlap occurred early in the execution and imagery walking actions, suggesting activation of shared action representations. Remarkably, a distinctive walking-related beta rebound occurred both during action execution and imagery at the end of the action suggesting that, like actual walking, motor imagery involves resetting or inhibition of motor processes. However, we also found that motor imagery elicits a distinct pattern of more distributed beta activity, especially at the beginning of the task. These results indicate that motor imagery and execution of naturalistic walking involve shared motor-cognitive activations, but that motor imagery requires additional cortical resources.

Control of Dynamic Biped Walking Robot

The objective of this article is to present control algorithms of biped dynamic walking robot. A mathematical model of the walking robot is compiled. The construction of the robot is based on minimalist design principles - absolutely solid body with two legs. Analytical dependencies between six coordinates of the body, coordinates of the left and right legs and absolute coordinates of the feet are defined. The block diagram of control system is presented. Differential equations of walking are compiled. The dynamic stability of biped walking robot near the required trajectory is provided by discrete control of the parameters: «when and where to put foot». To define these parameters, it is proposed to use an inverted mathematical pendulum as an ideal mechanism. Its linearized differential equations allow present the feet coordinates according to the measured initial and final parameters (at the begging and at the end of the step). The article paid particular attention to results of such control method with various walking modes. The coordinates of the robot body, its velocities and accelerations, angles of rotation were investigated. Calculations confirmed the small deviations of the proposed model of walking from the ideal one. The developed methodology allows improve the construction and control system of biped dynamic walking robots at the design stage. Some of the tasks, it can be used: design machines simulating human walking, with high speed and maneuverability, with point feet and synchronized with natural uncontrolled movements.

Управление статически неустойчивым шагающим аппаратом при ограниченном трении в опоре

A non-trivial problem in the biped walking is the preservation of stability under external influences without slowing down velocity. A dynamic walking control algorithm with a hierarchical structure is proposed in the article. The lower control level is organized according to the principle of tracking drives and ensures the position of the robot`s body using all given possible coordinates. The problem of traffic stabilization is solved at the upper level. An ideal mechanism — a flat inverted mathematical pendulum is considered in the feedback circuit. Its equations are synchronized by the moment of the step ending. Particular attention is paid to the interaction of the robot foot with the support surface to determine the conditions for the absence of slippage. Proposed control approach makes it possible to control the current position of the robot`s structure in the space in different walking modes without slowing down velocity. Critically assessing the results and prospects of the research, we can conclude about their use-fulness in the development of artificial intelligence cooperation with humans, about possible applications in everyday life, a specific environment and industry. The proposed approach may be applicable to the control of the walking mechanisms of similar mobile robots.

RObotic-Assisted Rehabilitation of Lower Limbs for Orthopedic Patients (ROAR-O): A Randomized Controlled Trial

Osteoarthritis is a common chronic condition in the elderly population and, with falls, represents a major public health problem. Patients with hip or knee osteoarthritis often have poor balance, which is considered an important risk factor for falls. In recent years, there has been increasing research supporting the use of robotic rehabilitation to improve function after total knee and hip replacement. The aim of this study is to investigate the effects of robotic balance rehabilitation on elderly patients who have undergone hip and knee replacement, with the aim of reducing the risk of falls and improving balance and walking, as well as motor function, fatigue, and overall quality of life. Twenty-four elderly patients with knee or hip replacement underwent robotic balance treatment with the Hunova® platform or conventional treatment three times a week for four weeks. Patients underwent an assessment of balance, walking, autonomy, quality of life and fatigue. Patients who underwent rehabilitation with Hunova® showed an improvement in dynamic balance (p = 0.0039) and walking (p = 0.001) and a reduction in both motor (p = 0.001) and cognitive (p = 0.05) fatigue. The study found that specific treatment for balance disorders in these patients could improve balance and reduce the risk of falling.

Model analysis and control of biped dynamic walker with fault steps in a gait cycle

The biped robot has two identical legs that undergo alternating stance and swing phases during walking. The robot’s motion is facilitated by actuators positioned at the ankle and hip joints. The paper investigates various fault scenarios in dynamic walker models, specifically situations where one or both actuators experience failure while the robot is in motion. The first model assumes faults in both the hip and ankle joints, while the second model assumes a fault only in the ankle joint. The dynamic walker typically undergoes two steps in each cycle. This study specifically examines the different types of faults that may occur during the second step. The goal is to identify the potential walking gaits that can result from these faults. It is observed that walking with faults at both the hip and ankle joints exhibited greater stability and a wider range of stable states compared to walking with a fault only at the ankle joint. This suggests that incorporating hip joint faults or underactuation into robotic or prosthetic gait patterns could improve their stability and overall performance. The local and global stability of the dynamic walker were analyzed using Poincare’s method and the basin of attraction plot, respectively. Additionally, a control algorithm based on kinetic energy shaping is proposed for the second model, which resulted in an increased basin of attraction. Notably, the second model exhibited the ability to walk with variable step length and speed, akin to human locomotion.