Swing Amplitude Research Articles

Моделирование поворотного механизма гидроманипулятора лесовозного автомобиля

The importance of loading and unloading operations in the technological process of wood hauling by timber trucks, as well as the need to improve the design of hydraulic manipulators, are considered. The most rational ways to increase the efficiency of their functioning are given. The disadvantages of traditional designs of hydraulic manipulator rotary mechanisms based on rack-and-pinion gears are presented. An improved design of the crank rotary mechanism of the hydraulic manipulator column from six hydraulic cylinders is proposed. The research methodology is based on the use of mathematical modeling. It has been revealed that the accumulated energy for one braking cycle when moving the load is about 1442 J. Considering that timber loading is carried out at a height of approximately 2 m, the recovery system allows approximately 12 % of the rotation energy to be directed to the load lifting operation. Over the entire range of change in the angle of the end of rotation, the recovered energy varies by only 7.1 % – from 1340 to 1442 J, and the load swing amplitude – by 1.2 % – from 0.336 to 0.340 m. It has been determined that with an increase in the length of the guide, the recovered energy decreases slightly – from 1564 to 1428 J (by 8.7 %) – and the load swing amplitude – from 0.344 to 0.339 (by 1.5 %). It has been found that over the entire angular range, the recovered energy varies from 1399 to 1442 J (by 3 %), and the load swing amplitude – from 0.3380 to 0.3393 m (by 0.4 %). The angular unevenness of the recovery efficiency indicators is no more than 3 %. To study the influence of the parameters of the crank rotary mechanism of the hydraulic manipulator column on the efficiency of energy recovery, a multifactor optimization problem has been solved. It has been established that the optimal value of the distance from the crank axis to the movable axes of the hydraulic cylinders of the rotary mechanism of the hydraulic manipulator column is 0.23–0.25 m, the optimal value of the displacement of the crank axis relative to the axis of the manipulator column is 0.17–0.18 m. At the same time, the recovered energy for 1 cycle of load moving is at least 1500 J, and the amplitude of the load swing is no more than 0.35 m.

A Kelp Inspired High‐Power Density Triboelectric Nanogenerator with Stacking Structure for Multiple Directional Ocean Wave Energy Harvesting

AbstractOcean wave energy is one of the most promising green energies in the wild. However, it is still challenging to effectively collect wave energy due to its randomness and irregularity. In this work, a kelp inspired high‐power density triboelectric nanogenerator (K‐TENG) is presented for harvesting wave energy with characteristics in multiple directions. The proposed K‐TENG consists of a series of stacked leaf‐like units. The influence of configuration parameters, including pellet diameters, pellet numbers, unit sizes, oscillation frequency, swing amplitude, and wave directions on output performances of leaf‐like units, are extensively investigated. Experimental data indicates that a single leaf‐like unit can achieve a maximum output voltage of 623.14 V as well as a maximum current of 1.48 µA and realize energy harvesting from different wave directions. A K‐TENG composed of 15 leaf‐like units demonstrates a high‐power density of 18.77 W m−3 at a wave frequency of 2.5 Hz, which successfully powers a digital watch and 414 light‐emitting diodes (LEDs). This work is hoped to provide a simple and reliable route to effectively harvest ocean wave energy.

How does running technique change with running speed? A quantitative analysis based on practice-informed principal components

Introduction & Purpose “Running technique is an important component of running economy and performance” (Folland et al., 2017). While economy and performance can directly be measured, no common measuring method exists for running technique. The aims of this study were twofold: (I) develop practice-informed running technique measures based on technique characterizations used by coaches (i.e. distinct variations of body segment movements instead of discrete kinematics); (II) investigate, how running technique changes with running speed. Methods Two independent kinematic data sets were recorded on a treadmill using a retro-reflective marker setup (“Plugin-Gait”) and a 10-camera system (Vicon Motion Systems Ltd., Oxford, UK). First, 20 experienced runners (age 25 ± 2 y; 10 females, 10 males) were tasked to vary their running according to 14 technique elements (vertical, horizontal, hip and upper body movement, foot strike, track width, ankle rotation, leg swing, back posture, elbow flexion/extension, arm swing amplitude and direction, gaze direction, cadence) into two opposing extreme forms per element. Measures for the 14 running technique elements were developed using principal component analyses (one PCA per two opposing technique element variations) and selecting principal components (PCs; Federolf, 2016) that aligned with the represented technique element. Second, an additional 19 experienced runners (age 30 ± 9 y, 3 females, 16 males) ran at different speeds (10-17 km/h with 1 km/h incremental steps) without any technique instructions. Their data were projected onto the selected PCs, resulting in averaged PC score waveforms of the different speeds along each technique element. Waveforms were analysed using statistical parametric mapping (SPM) with a repeated measures ANOVA design (Pataky et al., 2013). Results For all 14 technique elements, sections of significant differences between at least two different speeds were found within the cycle-normalized PC score waveforms. Figure 1 exemplifies the results for the foot track width, where the lateral range of motion of the feet decreased with speed. Post-hoc analyses revealed further differences, such as less vertical and greater horizontal movement, as well as smaller leg swing and greater arm swing amplitude at 17 km/h compared to 10 km/h. Discussion Firstly, practice-informed and data-driven running technique measures could be developed (I). Secondly, the measures could be applied on a group of runners and plausible changes in their technique due to running speed were identified (II). So far, the speed-dependent technique adaptations only reflect the specific techniques on a treadmill for a predominately male reference group, but the presented concept can be transferred to other runners and settings. Conclusion Running technique varies with speed, and the developed technique measures facilitate comparisons of these differences using practically relevant technique elements. Since the movement adaptations associated with running speed are directly quantifiable and visualizable, technique models for different speed ranges might be developed by researchers and then utilized by runners to train and assess their technique in alignment with these models.

A 3D printed serrated contact structure triboelectric nanogenerator for swimming training safety monitoring

The wearable electronic devices integrated with 3D printing have attracted much attention, but the continuous power supply demand and limited application scenarios have limited their development. Here, we propose a 3D printed serrated contact structure triboelectric nanogenerator (S-TENG) designed for mechanical energy harvesting and swimming training safety monitoring. Leveraging the advancements in 3D printing technology, we created a flexible, lightweight sensor integrated with polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET) films on a serrated substrate. This configuration enhances the contact surface area, leading to a significant improvement in energy harvesting efficiency compared to flat structures. Specifically, the serrated structure resulted in a 64 %, 63 %, and 47 % increase in open-circuit voltage (Voc), short-circuit current (Isc), and transferred charge (Qsc), respectively, owing to the contact area and unique surface functional structure. The S-TENG device exhibits excellent performance under various bending angles, with Voc, Isc, and Qsc reaching up to 98.04 V, 4.35 μA, and 38.51 nC at 90° bending. Additionally, the S-TENG maintains stable output in different humidity environments due to its fully encapsulated design, ensuring reliable operation in aquatic settings. The S-TENG can accurately measure elbow swing amplitude and frequency, providing valuable real-time data for athletes and coaches. The S-TENG's ability to detect irregular movements and potential drowning incidents underscores its promise in enhancing swimmer safety. This research demonstrates the S-TENG's utility in both energy harvesting and motion monitoring, paving the way for advanced wearable sports sensors in various athletic disciplines.

A 40 mV cold-start circuit with bootstrap clock booster for thermoelectric energy harvesting

In this paper, a cold-start circuit with bootstrap clock booster for thermoelectric energy harvesting is proposed. The relationship between enhancing the clock swing amplitude and lowering the input voltage for a cross-coupled charge pump (CCCP) is analyzed. Based on the existing one-shot start-up mechanism, a series-parallel bootstrap clock booster (SP-BCB) for boosting the clock amplitude is proposed to lower the cold start voltage. Besides, a dynamic threshold MOS (DTMOS) technique for dynamically changing the threshold voltage of MOS transistors is used to achieve better conduction and leakage current suppression. The complete circuit is simulated in a 0.18-μm CMOS process. The simulated results demonstrate that using DTMOS technique and enhancing the clock swing amplitude can contribute to lowering the input voltage. The SP-BCB-based CCCP can boost the input voltage from 40 mV to 668 mV for a 500 MΩ load in 100 m s, which meets the requirement for one-shot start-up mechanism, realizing 40-mV integrated cold start for thermoelectric energy harvesting (TEH).

Effect of Swing Amplitude on Microstructure and Properties of TC4 Titanium Alloy in Laser Welding

The welding of TC4 titanium alloy sheets with a thickness of 1 mm was successfully accomplished by a swinging laser. The microstructure and mechanical properties of the welding seam under different swing amplitudes were studied. In this paper, the microstructure, phase composition, mechanical properties, and fracture morphology of the weld with swing frequency of 50 Hz and different swing amplitudes (0.2 mm, 1 mm, 2 mm, and 3 mm) were tested and analyzed. The results show that basket-weave microstructures are present in the fusion zone of welds under different oscillation amplitudes, but the morphology of martensite within the basket-weave differs. The weld microstructure is mainly composed of acicular α′ martensite, initial α phase, secondary α phase, and residual β phase. The hardness of the weld is higher than that of the base metal, and the overall hardness decreases from the weld center to the base metal. When the oscillation amplitude A = 1 mm, the weld microstructure has the smallest average grain size, the highest microhardness (388.86 HV), the largest tensile strength (1115.4 MPa), and quasi-cleavage fracture occurs. At an oscillation amplitude of A = 2 mm, the tensile specimen achieves the maximum elongation of 14%, with ductile fracture as the dominant mechanism.

Thermal analysis by numerical simulations of a multilayered coating applied on a heavy-duty diesel engine piston

A methodology to numerically study the impact of a thin, multi-layer coating applied on the piston crown surface of an internal combustion engine is proposed. It relies on a loose thermal coupling between 3D-RANS simulations of the combustion chamber and 3D conduction simulations of the piston. The approach allows to characterize the transient thermal behavior of the piston, which is crucial to capture the thermal swing effect of the coating, as well as its potential impact on the combustion, heat transfer and engine efficiency. This methodology is used to simulate the impact of a 200-µm, 3-layer coating, applied on the piston crown surface of a single-cylinder, heavy-duty Diesel engine, for one operating point. No gain in terms of efficiency is observed with the coated piston (the decrease in heat losses through the piston surface due to the coating is counter-balanced by an increase in heat losses through the non-coated cylinder head). However, the methodology proves capable of predicting a coherent thermal behavior of the coated piston (decrease in piston body temperature of 5 K, average bowl surface temperature swing amplitude of 60 K, <5 K temperature swing at the interface between the metallic substrate and the coating) and is able to provide insightful information regarding the impact of coating on volumetric efficiency, heat losses, combustion but also on the coating reliability itself, for a reduced computational cost compared to a fully coupled approach. It can then be employed to evaluate the effect of a coating applied not only on the piston but also on the cylinder head, which would certainly have a more significant impact on the engine efficiency.

Single-file movement of pedestrians at different visibility levels

Previous studies indicate that the movement of pedestrians under poor visibility conditions is significantly different from that under good visibility conditions. To investigate the influence of visibility factor on the longitudinal movement of pedestrian, series of single-file experiments were performed under the quantitative control of visibility level. Based on the extracted trajectories, typical evacuation behavior and movement characteristics of pedestrians under different visibility conditions are explored. It is found that the lateral swing amplitude of pedestrians during movement is within 20 cm under low densities while it is close to 30 cm at high densities. The free velocity under the light transmission of 100 %, 2.2 %, 0.5 % and 0.1 % is 0.856 m/s, 0.823 m/s, 0.741 m/s and 0.712 m/s respectively. Individuals cannot accurately perceive the surrounding situations with the worsening of visual condition, therefore the movement speed decreases under the poor visibilities. Besides, two regimes including the constrained regime and free regime are identified in the headway-velocity relation at different visibility levels. The maximum specific flow under the light transmission of 100 %, 2.2 %, 0.5 % and 0.1 % is 0.70 s−1, 0.67 s−1, 0.62 s−1 and 0.55 s−1 respectively. The study is helpful to reveal the pedestrian dynamics of single-file movement under the limited visibility conditions.

Multi-scale keypoints detection and motion features extraction in dairy cows using ResNet101-ASPP network

Detecting Keypoints in dairy cows aims to locate and track the motion trajectories of the body's joints, which plays a crucial role in behavior analysis and lameness detection. However, real farming scenarios, characterized by occlusions and large variations in object scale may result in poor detection results. Therefore we introduce the atrous spatial pyramid pooling (ASPP) module into the shallow network of ResNet101, designed to improve the multi-scale feature extraction capability of the model. The ASPP module enhances the robustness of recognition for different dimensional sizes and occluded keypoints using different dilatation rates in the parallel atrous convolutional layers to expand the model's receptive field. Furthermore, seven types of motion features, including tracking up, gait symmetry, step height balance, motion speed variability, head swing amplitude, head-neck slope and back curvature are extracted simultaneously by monitoring and tracking the motion trajectory of distinct keypoints. Several of these features represent innovative extraction models and attributes, first proposed in this study. Multiple models are trained and tested on datasets containing 2385 frames for ablation experiments. The experiments show that, in comparison with the ResNet50, MobileNet_v2_1.0, and EfficientNet-b0 backbone networks, the training error and test error of ResNet101 improve by 4.04–30.12 pixels and 3.81–28.14 pixels. Therefore, ResNet101 is used as the benchmark for subsequent model improvement by adding the ASPP module. The training error and test error of the ResNet101-ASPP network are improved by 0.27 and 0.24 pixels, respectively, compared to the benchmark network. The prediction confidence improves by 1.65-2.50% at three different dairy cow object scales, In addition, the keypoints under different occlusion conditions improve considerably, especially for small-scale keypoints, demonstrating the capability of the ASPP module for multi-scale feature extraction. By analyzing the distribution between the seven features and health, mild lameness, and severe lameness in dairy cows, it is shown that all the different features play an important role in distinguishing between different levels of lameness.

Design and movement mechanism analysis of a multiple degree of freedom bionic crocodile robot based on the characteristic of “death roll”

AbstractThis paper introduces a multi‐degree of freedom bionic crocodile robot designed to tackle the challenge of cleaning pollutants and debris from the surfaces of narrow, shallow rivers. The robot mimics the “death roll” motion of crocodiles which is a technique used for object disintegration. First, the design incorporated a swinging tail mechanism using a multi‐section oscillating guide‐bar mechanism. By analyzing three‐, four‐, and five‐section tail structures, the four‐section tail was identified as the most effective structure, offering optimal strength and swing amplitude. Each section of the tail can reach maximum swing angles of 8.05°, 20.95°, 35.09°, and 43.84°, respectively, under a single motor's drive. Next, the robotic legs were designed with a double parallelogram mechanism, facilitating both crawling and retracting movements. In addition, the mouth employed a double‐rocker mechanism for efficient closure and locking, achieving an average torque of 5.69 N m with a motor torque of 3.92 N m. Moreover, the robotic body was designed with upper and lower segment structures and waterproofing function was also considered. Besides, the kinematic mechanism and mechanical properties of the bionic crocodile structure were analyzed from the perspectives of modeling and field tests. The results demonstrated an exceptional kinematic performance of the bionic crocodile robot, effectively replicating the authentic movement characteristics of a crocodile.

Experimental study on the cryogenic distillation system for high-purity liquid nitrogen under offshore conditions

Cryogenic distillation is widely acknowledged as the primary industrial method for producing liquid nitrogen of high purity. However, the distillation process is highly sensitive to tilting and swinging, which limits the application of cryogenic air separation in offshore infrastructures. This paper proposes a small-scale air separation process that incorporates a dual-column distillation to enhance distillation performance under offshore conditions. Experiments were conducted under standard (no-tilting and stationary), tilting, and swinging conditions. The results indicate that the proposed distillation plant can maintain nitrogen purity to a certain extent under offshore conditions. The product impurity (oxygen content) increased significantly as the tilting angles increased beyond 4° for horizontal titling and 3° for longitudinal titling, respectively. The distillation performance was less affected by the swing than the tilting. High-purity nitrogen could be produced when swing amplitude was within ±10° and swing period was between 6 s and 11 s. The results can provide engineering guidance for the design and installation of the columns of air-separation plants.

Flexibility evaluation of psammophytes using Young’s modulus based on 3D numerical simulation

Flexible psammophytes play an important role in controlling soil wind erosion and desertification, owing to their characteristics. Although flexibility of psammophytes has been considered in previous studies, the interaction between flexible psammophytes and the surrounding airflow field still remained unclear. In this study, we used the Young’s modulus to describe plant flexibility and conducted a 3D computational fluid dynamics simulation using a standard k-ε model and a fluid–structure interaction model. Taking Caragana korshinskii (Caragana), a typical psammophyte, as the research object, we constructed 3D geometric models with different diameters to simulate the airflow field around the flexible psammophytes. By comparing with the simulation results of rigid plants and simulation results of flexible plants at different wind speeds, we could verify the rationality of the simulation method. Based on the simulation results, the maximum swing amplitude of the model and the Young’s modulus were found to have a negative correlation, presenting an exponential functional relationship with good fitting. The relationship between the actual Young’s modulus of the plant branches and that of different diameter models in the numerical simulation was also established. This study is expected to improve our basic understanding of the interaction between flexible psammophytes and the surrounding airflow field, and provide some qualitative reference for the numerical simulation of the airflow field around flexible psammophytes.

The Formability and Mechanical Properties of 316L Stainless Steel Fabricated by Pulsed Arc Swing Additive Manufacturing

An austenitic stainless steel 316L deposition specimen is fabricated by cold metal transfer‐based swing arc additive manufacturing (CMT‐SAAM), and its formation, microstructure, and tensile properties are investigated. The results showed that the 316L deposited samples exhibited a multi‐layer structure with a small aspect ratio, and the surface forming accuracy is improved with the increase in the swing amplitude. The remelted zone near the interface is dominated by long grains perpendicular to the fusion line, whereas the deposited zone is dominated by columnar dendrites and shows an <100> orientation. Along the building and transverse direction of the swing deposits, the microhardness distribution is uniform. Compared with rollings and forgings, 316L deposited by using the CMT‐SAAM method has both a higher strength and toughness. The average ultimate tensile strength is 573 MPa, and the elongation at break is 52.6%. The high strength and toughness of 316L specimens are attributed to the fine microstructure, high‐density dislocations, and low‐angle grain boundaries (LAGBs) generated during the CMT‐SAAM process.

Performance improvement in reservoir computing by using HfZrO2 FeFETs through operating voltage optimization

We have investigated how the parameters of an input gate voltage (V g) waveform and a drain voltage (V d) impact the performance of reservoir computing (RC) using a Hf0.5Zr0.5O2 ferroelectric FET (FeFET). The RC performance is maximized by the high swing amplitude of the V g and the most symmetrical polarization switching condition in the triangular-shaped input waveform, obtained by the center V g of 0.5 V, because of the enhanced polarization switching of the FeFETs. Regarding the V d dependence, the amount of the drain current and polarization switching have a trade-off relationship. As a result, a moderate V d of 1.0 V becomes optimum in terms of the RC performance because a difference in drain current responses between different gate input patterns is maximized with this V d. Furthermore, high computing capacities are achieved by combining the above optimal bias condition with drain current responses to both original and inverted gate input patterns.

Triboelectric-electromagnetic hybrid nanogenerator for harvesting blue energy and creating an ocean wave warning system.

The abundant water wave energy on Earth stands as one of the most promising renewable blue energy sources, as it exhibits minimal dependence on weather, time and temperature. However, the low fluctuation frequency and extremely irregular nature of the wave energy restrict both the methods and efficiency of energy harvesting. In this study, a packed box-like hybrid nanogenerator was designed, comprising two single-electrode triboelectric nanogenerators (TENGs) and two electromagnetic generators (EMGs). The outputs of both the TENG and EMG were demonstrated under different fluctuation frequencies and swing amplitudes, inspiring the development of a wave warning system. The maximum output voltage, current, and transferred charge of the single TENG, as part of hybrid nanogenerator (HG), reach approximately 110 V, 2.3 μA, and 50 nC, respectively. Its peak power reaches 85.3 μW under a resistance load of 20 MΩ at a frequency of 2 Hz. The EMG component produced maximum output voltages and currents of up to 0.45 V and 1.2 mA, respectively. The peak power is approximately 95.6 μW with a resistance load of 200 Ω. The output performances of the TENG and EMG increase linearly with the increase in the swing angle. Most importantly, a packed box-like hybrid nanogenerator can be conveniently packaged for harvesting energy from water waves. A wave energy collection array floating on the sea is proposed for harvesting blue energy and creating a self-powered ocean wave warning system.

Enhancing Sperm Motility Parameters in Patients with Asthenospermia: A Combined Approach of Acupuncture at Fusiguan Point and Tamoxifen Citrate Tablets.

To explore the effect of acupuncture at Fuguan point combined with tamoxifen citrate tablet on sperm motility parameters. A total of 115 individuals with asthenospermia were categorized based on different treatment regimens: 53 patients in the control group (receiving tamoxifen citrate tablets) and 62 patients in the observation group (undergoing acupoint acupuncture in conjunction with tamoxifen citrate tablets). Both groups underwent a 3-month treatment period. The computer-assisted sperm analysis system was employed to measure various motility parameters of human sperm, including sperm motility rate, average path velocity (VAP), lateral swing amplitude (ALH), percentage of class a sperm, and percentage of class a + b sperm. Prior to treatment, no statistically significant differences were observed between the two groups in terms of sperm motility rate, VAP, ALH, percentage of class a sperm, and percentage of class a + b sperm (p > 0.05). Following treatment, both groups exhibited significant enhancements in sperm motility rate, VAP, ALH, percentage of class a sperm, and percentage of class a + b sperm compared to pretreatment levels (p < 0.05). Furthermore, all measured indicators in the observation group demonstrated significantly superior improvements than those of the control group, with the differences proving statistically significant (p < 0.05). The combination of acupuncture at Fusiguan point and tamoxifen citrate tablets exerts a notably positive effect on sperm motility in individuals diagnosed with asthenospermia.

Specific Point in Time Excitation Control Method for Spatial Multi-Degree-of-Freedom Systems under Continuous Operation

The port container gantry crane studied in this paper is a four-degree-of-freedom spatial continuous system. In actual work, in order to make the container transfer smoothly, the response of the whole system needs to be accurately predicted and timely adjusted. The whole system is divided into rotary mechanism, lifting mechanism, lifting trolley mechanism, and big cart mechanism for detailed analysis. By constructing the field transfer matrix, a one-dimensional wave equation of continuous system and the Lagrange equation with redundant parameters, the response of each subsystem is solved precisely. The results of the study found that in some periods, the swing of the container was too large. In order to improve the safety and stability of transmission, an active control method of specific point in time excitation (SPE) is proposed for the first time. This method predicts the swing amplitude of the container in advance using the response results of the numerical model. When the set response interval is exceeded, the external excitation intervention can effectively inhibit the moving range of the container in the transit process. Finally, the results are compared with the simulation model to achieve the experimental purpose. It is in line with the expected experimental effect.

Modeling and analysis of the cutting temperature of titanium alloys for quasi-intermittent vibration assisted swing cutting

EVC has proven to be an effective means of machining difficult-to-process materials. QVASC inherits EVC's intermittent cutting and friction reversal advantages, eliminating EVC cutting residues and improving machining quality. In order to deeply understand the cutting mechanism of QVASC, it is necessary to understand the cutting heat generation and tool surface temperature distribution in the process of QVASC. In this paper, the kinematic and frictional characteristics of the QVASC machining process are analyzed, the heat generation and heat transfer model of QVASC machining process is established, and the cutting temperature prediction model considering the characteristics of QVASC machining is proposed. According to whether there is heat convection and frictional shear stress distribution between the tool and the environment, the heat flow distribution of the front surface of the tool is divided into four regions, and the heat flux of the tool is calculated respectively. On this basis, the tool temperature of QVASC is solved by using the heat balance equation in the form of the partial differential equation. Finally, a systematic comparison experiment was carried out, and the effects of cutting depth, cutting speed, tool swing frequency, and amplitude on cutting temperature were studied by single factor method. The results show that the average cutting temperature of QVASC is 10 % lower than that of OC, which verifies the advantage of QVASC in reducing cutting temperature. Under different cutting depth, cutting speed, tool swing frequency and amplitude, the change trend of theoretical and experimental cutting temperature is the same, and the average error between them is 9 %, 8 %, 10 % and 9 %, respectively, which is within the acceptable range, proving the validity of the theoretical model. This research contributes to a deep understanding of the cutting process of QVASC and effectively determines the optimal cutting parameters.

Kinematic modeling and hybrid motion planning for wheeled-legged rovers to traverse challenging terrains

AbstractThis paper presents a kinematics modeling and hybrid motion planning framework for wheeled-legged rovers. It is a unified solution for wheeled-legged rovers to traverse multiple challenging terrains using hybrid locomotion. A kinematic model is first established to describe the rover’s motions. Then, a hybrid motion planning framework is proposed to determine the rover’s gait patterns and parameterize the legs’ and the body’s trajectories. Furthermore, an optimization algorithm based on B-spline is utilized to minimize the motors’ energy dissipation and generate smooth trajectories. The wheeled and legged hybridization allows the rover for faster locomotion while maintaining high stability. Besides, it also improves the rover’s ability to overcome obstacles. Prototype experiments are carried out in more complex environments to verify the rover’s flexibility and maneuverability to traverse irregular terrains. The proposed algorithm reduces the swing amplitude by 83.3% compared to purely legged locomotion.

The influence of diabetes and age-related degeneration on body balance control during static standing: a study based on plantar center-of-pressure trajectories and principal component analysis

BackgroundAging and diabetes can impair the balance function of the elderly and diabetic patients and increase their fall risk. This study aimed to assess the shaking amplitude of the center-of-pressure (CoP) during static standing, to analyze the effects of aging and diabetes on the balance control.Materials and methodsThis cross-sectional observational study, compared the balance performance of 20 healthy younger adults (27.65 ± 5.60 years), 16 healthy older adults (58.88 ± 3.54 years) and 15 diabetic patients (58.33 ± 5.33 years) in four static standing conditions on a force plate: horizontal, anteroposterior (AP), left and right slope planes (5° angles on AP, left and right directions, respectively). The trajectory coordinates of the CoP over time were recorded and analyzed by principal components analysis to obtain the 95% confidence ellipse and its parameters: angle, major and minor axes lengths, and area. The balance indicators were compared among the three groups using one-way analysis of variance (ANOVA), Brown–Forsythe test or Kruskal–Wallis H test, depending on the normality and homogeneity of variance assumptions.ResultsThe diabetic group had a significantly larger confidence ellipse area than the healthy younger adults on the horizontal plane (P = 0.032) and than the healthy older adults on the horizontal (P = 0.036), AP slope (P = 0.023), and right ML slope (P = 0.037) planes. There were no significant differences in the major axis length of the confidence ellipse among the three groups. The diabetic group had a significantly longer minor axis length than the healthy younger adults on the AP slope (P = 0.039), left ML slope (P = 0.045) and right ML slope (P = 0.016) planes and than the healthy older adults on the AP slope (P = 0.007), left ML slope (P = 0.035) and right ML slope (P = 0.012) planes.ConclusionsThe balance control of diabetic patients is decreased compared with healthy younger and older people, and the body swing amplitude increases mainly in the direction of minor axis of confidence ellipse during static standing, while the swing amplitude in the direction of the major axis has no significant change. Evaluating the balance function of diabetic patients can help clinicians identify people with fall risk early and intervene early, thereby reducing the occurrence of fall events in this population.