Joint Rotation Research Articles

Foot posture index and hip joint rotation mobility in handball and soccer players

Purpose: To assess the foot posture and hip joint mobility of elite handball and soccer players and to investigate possible correlations between these measurements. Methods: We compared the differences in means of Foot Posture Index (FPI), passive hip internal (IR), and external (ER) rotation range of motion (ROM) between three groups of male subjects (17 handball players, 17 soccer players, and 16 non-athletes). The Kruskal-Walli’s test and post-hoc pairwise comparison with the Mann-Whitney U test were used to determine the differences between the group means, and associations between variables were analyzed with Spearman’s correlation coefficient. Results: No significant differences in the mean FPI were found between the soccer players (1.3 ± 2.9), handball players (0.7 ± 2.1), and the control group (1.7 ± 2.5) (p > 0.05). Similarly, no significant difference was found between the groups in the hip ER ROM. In contrast, a significantly lower (p < 0.05) hip IR ROM was observed in the soccer players (30.6° ± 5.3°) compared to the handball players (41.0° ± 8.1°) and the control group (41.1° ± 6.4°). A weak positive correlation was only observed between the FPI and hip IR ROM in the soccer players (ρ: 0.36, p = 0.035). Conclusions: Handball and soccer players show a tendency toward less pronated feet compared to non-athletes, but the differences are not significant and the mean FPI values are still within the range of normal foot posture. The range of hip IR seems to be reduced in soccer players and weakly, but significantly and positively associated with the FPI value, which needs to be further investigated in future studies.

Dynamic error modeling and analysis of articulated arm coordinate measuring machine with integrated joint module

The self-driven articulated arm coordinate measuring machine (AACMM) is a new non-orthogonal flexible coordinate measuring equipment providing automatic positioning and measurement with integrated joint modules introduced to its rotary joints. The dynamic measuring accuracy is the crucial indicator of the self-driven AACMM performance. However, the part manufacturing assembly error and structural dynamic deformation error will seriously reduce the dynamic measuring accuracy. Therefore, a modeling compensation approach based on error propagation and accumulation mechanism analysis of the above two aspects is necessarily required to preserve the automatic measuring accuracy of the self-driven AACMM. In this paper, the authors propose an innovative modeling method for evaluating and compensating for the dynamic measuring errors of the self-driven AACMM. The ideal measuring model is constructed assisted with on the classical Denavit–Hartenberg parameter methodology and the complex structure of the self-driven AACMM. The source and its propagation mechanism of the dynamic error from the self-driven AACMM were analyzed systematically to decouple the superposed error impact on measuring precision. The dynamic measurement error compensation mechanism model is presented considering the influence of instantaneous spatial attitude on the dynamic structural parameters of self-driven AACMM. Experimental results indicate that the single-point repeatability measurement error fluctuation of the self-driven AACMM is 0.046 mm. The radius measuring error of the gauge ball reduces from −0.26 mm to −0.19 mm after the error model compensation. Additionally, the measuring accuracy is demonstrated to be effectively improved by the dynamic error compensation mechanism model.

Influence of the depth of friction-welded dowels on the strength of rotary welded joints

One of the important factors in rotary welding is the depth of welding of the dowel as well as the direction of welding of the dowel. In the studied interval (welding depth of 15 to 30 mm), the pull-out force increased when welding the dowel parallel to the wood grain and perpendicular to the wood grain. The strength of the welded joint increased from 15 to 20 mm, and then it continuously decreased towards a welding depth of 30 mm. The reason for this is that the tip of the dowel is intensively worn, and with a welding depth of 20 mm, it is approximately equal to the diameter of the hole. Therefore, by increasing the welding depth, the pull-out force increases slightly (due to the friction between the dowel and the hole wall), and the strength of the joint decreases. The highest joint strength was achieved at a welding depth of 20 mm for specimens welded parallel to the grain (PV) and specimens welded perpendicular to the grain (RTV). In welded joints where the dowels are loaded only by tensile force, it is recommended to use a welding depth of 30 mm.

Berthing proximity maneuvers and trajectory planning of a space manipulator via Kane’s formulation

On-orbit servicing is one of the most challenging tasks of the recent space era. Space Manipulator Systems (SMS) can represent viable technological solutions for several space operations, such as in-situ refueling, repairing of operating spacecraft, or debris grappling. Regardless of the specific task, SMS must approach the target object and then establish a physical connection with it using a single or more robotic arms. This work considers a space vehicle equipped with a pair of two-link robotic arms, with the intent of efficiently designing and simulating the overall spacecraft dynamics until contact takes place. The links that compose each arm are modeled as rigid bodies, assuming relatively slow dynamics. Instead, flexibility is introduced in the model of the rotary joints. The overall dynamics is investigated using Kane’s methodology, which is general, highly systematic, and joins the advantages of both the Newton/Euler and the Lagrange formulation. Both SMS and the target, assumed as noncooperative, are placed in low Earth orbit, in close proximity. Trajectory planning of the robotic arm is investigated, while considering the effect of the arm motion on the overall attitude dynamics. Precise attitude maneuvering is mandatory in order that grappling be successfully completed. To do this, a quaternion-based, globally stable attitude feedback law is designed, implemented, and tested. Actuation is demanded to an arrangement of control momentum gyroscopes. These devices are modeled with the inclusion of gyroscopic coupling effects, and are driven by means of suitable steering laws, for the purpose of pursuing the desired attitude control action. Accurate modeling of SMS, with also the inclusion of disturbances due to joint flexibility, in conjunction with the use of suitable feedback attitude control and steering laws for both the robotic arms and the actuation devices, allows obtaining the desired variables, i.e. (i) the motor torques (for steering both the joints and the attitude devices) and (ii) the constraint actions (forces and torques). A Monte Carlo analysis points out effectiveness of the control architecture proposed in this study in the challenging mission scenario of interest.

Impact of Coracohumeral Ligament Release on Treatment Outcomes in Patients with Idiopathic Adhesive Capsulitis

Background. The coracohumeral ligament restricts external rotation of the shoulder joint and, along with the upper, middle, and lower glenohumeral ligaments, participates in stabilizing the shoulder joint. There is ongoing debate regarding the division of this anatomical structure in patients with limited external rotation. Objective: to compare the treatment outcomes of patients with idiopathic adhesive capsulitis who underwent coracohumeral ligament release along with selective capsulotomy to those who underwent only partial coracohumeral ligament release. Material and Methods. We treated 85 patients with idiopathic adhesive capsulitis, who were divided into two groups: group 1 underwent selective anterior capsulotomy of the shoulder joint with the division of the middle and lower glenohumeral ligaments, biceps long head tenotomy, subacromial decompression, and partial coracohumeral ligament release; group 2 underwent a similar surgical procedure with complete coracohumeral ligament excision. The average age of the patients was 47.9±19.1 years. The function of the shoulder joint was assessed using the Constant Shoulder Score and VAS scales before surgery and at 3 and 6 months postoperatively. Results. At 3 months postoperatively, group 2 showed a slightly better functional outcome according to the Constant Shoulder Score (12.2±6.9 points) compared to group 1 (18.1±6.4 points, p=0.038). At 6 months postoperatively, group 1 had a mean Constant Shoulder Score of 15.1±7 points, while group 2 had a score of 10.1±6.3 points (p=0.02). Conclusions. Excision of the coracohumeral ligament in patients with idiopathic adhesive capsulitis allows for better functional outcomes according to the Constant Shoulder Score and VAS at both 3 and 6 months postoperatively.

Development and optimization of a prediction system model for mechanical properties in rotary friction-welded polyamide joints using the SVM approach and GA optimization

Development and optimization of a prediction system model for mechanical properties in rotary friction-welded polyamide joints using the SVM approach and GA optimization

Peroneus Brevis to Longus Tendon Transfer in the Treatment of Flexible Progressive Collapsing Foot Deformity: A Cadaveric Study.

Although operative treatment of the flexible progressive collapsing foot deformity (PCFD) remains controversial, correction of residual forefoot varus and stabilization of the medial column are important components of reconstruction. A peroneus brevis (PB) to peroneus longus (PL) tendon transfer has been proposed to address these deformities. The aim of our study was to determine the effect of an isolated PB-to-PL transfer on medial column kinematics and plantar pressures in a simulated PCFD (sPCFD) cadaveric model. The stance phase of level walking was simulated in 10 midtibia cadaveric specimens using a validated 6-degree of freedom robot. Bone motions and plantar pressure were collected in 3 conditions: intact, sPCFD, and after PB-to-PL transfer. The PB-to-PL transfer was performed by transecting the PB and advancing the proximal stump 1 cm into the PL. Outcome measures included the change in joint rotation of the talonavicular, first naviculocuneiform, and first tarsometatarsal joints between conditions. Plantar pressure outcome measures included the maximum force, peak pressure under the first metatarsal, and the lateral-to-medial forefoot average pressure ratio. Compared to the sPCFD condition, the PB-to-PL transfer resulted in significant increases in talonavicular plantarflexion and adduction of 68% and 72%, respectively, during simulated late stance phase. Talonavicular eversion also decreased in simulated late stance by 53%. Relative to the sPCFD condition, the PB-to-PL transfer also resulted in a 17% increase (P = .045) in maximum force and a 45-kPa increase (P = .038) in peak pressure under the first metatarsal, along with a medial shift in forefoot pressure. The results from this cadaver-based simulation suggest that the addition of a PB-to-PL transfer as part of the surgical management of the flexible PCFD may aid in correction of deformity and increase the plantarflexion force under the first metatarsal. This study provides biomechanical evidence to support the addition of a PB-to-PL tendon transfer in the surgical treatment of flexible PCFD.

Fast Human Motion reconstruction from sparse inertial measurement units considering the human shape

Inertial Measurement Unit-based methods have great potential in capturing motion in large-scale and complex environments with many people. Sparse Inertial Measurement Unit-based methods have more research value due to their simplicity and flexibility. However, improving the computational efficiency and reducing latency in such methods are challenging. In this paper, we propose Fast Inertial Poser, which is a full body motion estimation deep neural network based on 6 inertial measurement units considering body parameters. We design a network architecture based on recurrent neural networks according to the kinematics tree. This method introduces human body shape information by the causality of observations and eliminates the dependence on future frames. During the estimation of joint positions, the upper body and lower body are estimated using separate network modules independently. Then the joint rotation is obtained through a well-designed single-frame kinematics inverse solver. Experiments show that the method can greatly improve the inference speed and reduce the latency while ensuring the reconstruction accuracy compared with previous methods. Fast Inertial Poser runs at 65 fps with 15 ms latency on an embedded computer, demonstrating the efficiency of the model.

Automated Symbolic Processes for Dynamic Modeling of Redundant Manipulator Robots

In this study, groundbreaking software has been developed to automate the generation of equations of motion for manipulator robots with varying configurations and degrees of freedom (DoF). The implementation of three algorithms rooted in the Lagrange–Euler (L-E) formulation is achieved through the utilization of .m files in MATLAB R2020a software.This results in the derivation of a symbolic dynamic model for industrial manipulator robots. To comprehend the unique features and advantages of the developed software, dynamic simulations are conducted for two 6- and 9-DoF redundant manipulator robots as well as for a 3-DoF non-redundant manipulator robot equipped with prismatic and rotational joints, which is used to simplify the dynamic equations of the redundant prototypes. Notably, for the 6-DoF manipulator robot, model predictive control (MPC) is employed using insights gained from the dynamic model. This enables optimal control by predicting the future evolution of state variables: specifically, the values of the robot’s joint variables. The software is executed to model the dynamics of different types of robots, and the CPU time for a MacBook Pro with a 3 GHz Dual-Core Intel Core i7 processor is less than a minute. Ultimately, the theoretical findings are validated through response graphs and performance indicators of the MPC, affirming the accurate functionality of the developed software. The significance of this work lies in the automation of motion equation generation for manipulator robots, paving the way for enhanced control strategies and facilitating advancements in the field of robotics.

Device for Measuring Forces and Torques in Flexible Connection Joints for Parabolic Trough Collector

Measurement of forces and torques in flexible connection joints for parabolic trough collectors (PTC) during their life time is important to prevent damage or breakage of these elements. Plataforma Solar de Almería (PSA) has developed and patented a device for measuring these forces and torques in flexible connection joints installed in solar power plants. The device consists of three dynamometers and one torque transducer coupled to a rotation assembly that can be externally coupled to a ball joint installed in interconnections of parabolic-troughs, with no interference in the hydraulic circuit. To calibrate the device and perform initial performance checks at lab scale, a test bench was prepared for applying forces and torques on a set-up composed of a multicomponent sensor connected in series to a standard rotary ball joint and measuring simultaneously the forces and torques by mean of the designed device. Calibration tests have been performed applying a range of forces and torques to the multicomponent sensor-ball joint at different rotation positions. Multicomponent sensor and developed device measurements have been compared to obtain a calibration matrix for the last one. Results show good performance of the device once calibrated, but that will be improved measuring angular deviations from reference axes position of each of the dynamometers that compose the device during the operation, to increase the accuracy of the measurements.

Sensory function and somatosensorial system changes according to visual acuity and throwing techniques in goalball players: A cross-sectional study.

The somatosensory system is a complect sensory system that differentiates individual athletes. The aim of this study is to investigate the effect of visual acuity level on throwing technique, proprioceptive sense of the shoulder joint, light touch and two-point discrimination sense of the upper extremity, and sensory function (postural control and reaction time) in visually impaired goalball players. Goalball players who have different visual acuities B1(unable to perceive light or recognize its shape); B2 (has a visual field of less than 5 degrees and can recognize shapes); B3 (visual field greater than 5 degrees and less than 20 degrees) participated in the study. The sensorial system was evaluated with proprioceptive sense of the shoulder joint and sensory tests (light touch and two-point discrimination sense of the dominant hand.). Sensory function (postural control and reaction time) was evaluated with the flamingo balance test, functional reach test, and pro-agility test. The goalball players' throwing technique was questioned. Seventeen male players, those aged 20-30 (20.8±3.9 years) who have been professionally engaged in goalball for at least three years (58.7-37.8 months) participated. Shoulder internal rotation joint position sense and the flamingo balance test were found to be different in the group with B1 visual acuity than in the group with B3 visual acuity (p = 0.042* and 0.028 respectively). There was no difference between groups with B1-B2 visual acuity (p = 0.394 and p = 0.065) and between groups with B2-B3 visual acuity (p = 0.792 and p = 0.931). There was no difference in the groups in terms of sensory tests and reaction time (p> 0.05). In goalball, joint position sense is related to throwing techniques. Although there is a general acceptance that other sensory systems should work harder to compensate for the sense of vision, fear of falling, athlete's branch year, sports year, muscle strength, and general physical condition of the athlete may affect the measurements made, especially in the dynamic position.

A GFDM based computational model for the analysis of tunnels under gravitational loadings

Based on an impedance relation, a new computational model is developed for the analysis of tunnels under gravitational loading. The shape of tunnel is arbitrary. The impedance matrix, representing the soil resistance, is evaluated through integration of the equations of elasticity by generalized finite difference method (GFDM). The rigidity matrix of tunnel ring is constructed by using two types of elements: plate and shell elements. The equations of these elements are evaluated through integration of the equations of higher order plate and shell theories again by GFDM. These element equations accommodate not only axial and bending deformations, but, also shear deformations in the ring. In the study, the rotational joint deformation is simulated through the use of rotational spring model and the slippage is considered by modifying the impedance matrix so that the tangential soil resistance force between the ring and soil medium vanishes. Some numerical results are presented, in nondimensional forms, for circular and square tunnels where the following three cases are considered for circular tunnels: a) the soil medium is infinite, the change in σv (vertical (in situ) compressional stress) in the vicinity of tunnel is disregarded b) the soil medium is infinite, the change in σv is taken into account c) the soil medium is halfspace (HS). In connection with the case of (a), a comparison is presented for the ring flexibility curves of radial displacement and section forces of circular ring with those reported in literature. In view of the interpretations of the results and comparisons, we think, the proposed model may be used reliably in the analysis of tunnels.

Analytical solution for buried pipeline deformation induced by normal and reverse fault considering structural joint influence

AbstractPrevious studies take less account of analytical solution analysis for buried pipeline under the action of active fault. Furthermore, current theoretical studies of fault‐pipeline interactions generally treat the structure as continuous pipeline, with less attention given to the effect of joints. This paper provides an analytical method to estimate the deformation and internal force of jointed pipelines under normal and reverse fault. By introducing the simplified soil deformation model and error function, the soil greenfield deformation curves under the influence of normal and reverse fault are obtained. Considering the interaction between the pipeline structure and the disturbed soil, the two‐parameter Pasternak foundation model is adopted to analyze the forces on pipeline infinitesimal elements. Then, the mechanical response of the jointed pipeline structure due to the fault additional load is solved by finite difference method. The accuracy of the presented analytical solution is verified by comparisons with observed data of model test and 3D numerical simulation results. Finally, the parametric analyses are performed to estimate the influence for the characteristics of the foundation, fault and joint, including subgrade shear stiffness, subgrade reaction coefficient, fault dip, joint rotational stiffness, joint spacing, and intersection of fault and pipeline.

Engineering design and testing of rotary joints’ driving systems for the CFETR multi-purpose overload robot

This study focuses on the engineering design and testing of the rotary joints' driving systems for the China Fusion Engineering Test Reactor (CFETR) Multi-Purpose Overload Robot (CMOR). CMOR is a critical component in the CFETR. The CFETR tokamak serves as an engineering test reactor in China for magnet confinement fusion research. CMOR, a 7-DOF manipulator, is specifically designed for internal maintenance within the CFETR. This poses significant challenges in the design of the joint driving systems. The joint types of CMOR are categorized into three, comprising one translation joint, two swing joints, and four rotary joints. Using rotary joint J6 of CMOR as an example, this paper provides a detailed exploration of the engineering design and testing of the rotary joints' driving systems, offering a comprehensive explanation of their design specifications and principles. Specification and strength assessments are conducted on the engineering design results, meeting all requirements. Furthermore, the paper delves into the testing methods of the driving systems, including the assessment of transmission error and backlash error, two crucial indicators for the driving system. This research contributes valuable insights for future joint designs and testing of the CMOR heavy-load manipulator.

Differential leg and trunk operation during skipping without and with hurdles in bipedal Japanese macaque.

When locomoting bipedally at higher speeds, macaques preferred unilateral skipping (galloping). The same skipping pattern was maintained while hurdling across two low obstacles at the distance of a stride within our experimental track. The present study investigated leg and trunk joint rotations and leg joint moments, with the aim of clarifying the differential leg and trunk operation during skipping in bipedal macaques. Especially at the hip, the range of joint rotation and extension at lift off was larger in the leading than in the trailing leg. The flexing knee absorbed energy and the extending ankle generated work during each step. The trunk showed only minor deviations from symmetry. Hurdling amplified the differences and notably resulted in a quasi-elastic use of the leading knee and in an asymmetric operation of the trunk.

Voluntary activation of human knee extensors during isotonic shortening contractions.

The interpolated twitch technique (ITT) is often used to assess voluntary activation during isometric contractions; however, this may have limited relevance to dynamic contractions. Although the ITT has been applied to relatively slow isokinetic contractions (< 150°/s), it has received limited consideration during unconstrained velocity (i.e., isotonic) contractions, despite their relevance to natural movements. Here, we explored the ITT during isotonic knee extension contractions using a modified dynamometer. Young males (n = 6) and females (n = 4) performed isometric and isotonic knee extension contractions of sub-maximal and maximal intensities with doublet (150 Hz) muscle belly stimulations to assess voluntary activation. Following each voluntary isotonic contraction (velocity range ~ 35°/s to ~ 275°/s), resting potentiated doublets were evaluated during passive joint rotation at the same angular velocity achieved during voluntary efforts, to account for force-velocity characteristics. Correlations between voluntary activation and the proportion of maximal torque or power were evaluated for isometric and isotonic contractions, respectively. Isometric voluntary activation was strongly correlated with increasing torque output (r = 0.96, p < 0.001). Doublet torque during passive joint rotation displayed a hyperbolic relationship with increasing angular velocity (r = 0.98, p < 0.001). Isotonic voluntary activation was strongly correlated with increasing power output (r = 0.89, p < 0.001). During maximal effort contractions, no differences were observed in voluntary activation between isometric and isotonic conditions (89.4% vs. 89.2%, p = 0.904). The ITT is a valid approach to evaluate voluntary activation during an isotonic contraction using a modified dynamometer. Participants were able to achieve a similar high level of voluntary activation during isometric and isotonic contractions.

The Simultaneous Model-Based Estimation of Joint, Muscle, and Tendon Stiffness is Highly Sensitive to the Tendon Force-Strain Relationship.

Accurate estimation of stiffness across anatomical levels (i.e., joint, muscle, and tendon) in vivo has long been a challenge in biomechanics. Recent advances in electromyography (EMG)-driven musculoskeletal modeling have allowed the non-invasive estimation of stiffness during dynamic joint rotations. Nevertheless, validation has been limited to the joint level due to a lack of simultaneous in vivo experimental measurements of muscle and tendon stiffness. With a focus on the triceps surae, we employed a novel perturbation-based experimental technique informed by dynamometry and ultrasonography to derive reference stiffness at the joint, muscle, and tendon levels simultaneously. Here, we propose a new EMG-driven model-based approach that does not require external joint perturbation, nor ultrasonography, to estimate multi-level stiffness. We present a novel set of closed-form equations that enables the person-specific tuning of musculoskeletal parameters dictating biological stiffness, including passive force-length relationships in modeled muscles and tendons. Calibrated EMG-driven musculoskeletal models estimated the reference data with average normalized root-mean-square error ≈ 20%. Moreover, only when calibrated tendons were approximately four times more compliant than typically modeled, our approach could estimate multi-level reference stiffness. EMG-driven musculoskeletal models can be calibrated on a larger set of reference data to provide more realistic values for the biomechanical variables across multiple anatomical levels. Moreover, the tendon models that are typically used in musculoskeletal modeling are too stiff. Calibrated musculoskeletal models informed by experimental measurements give access to an augmented range of biomechanical variables that might not be easily measured with sensors alone.

MmPose-FK: A Forward Kinematics Approach to Dynamic Skeletal Pose Estimation Using mmWave Radars.

In this paper, we propose mmPose-FK, a novel millimeter wave (mmWave) radar-based pose estimation method that employs a dynamic forward kinematics (FK) approach to address the challenges posed by low resolution, specularity, and noise artifacts commonly associated with mmWave radars. These issues often result in unstable joint poses that vibrate over time, reducing the effectiveness of traditional pose estimation techniques. To overcome these limitations, we integrate the FK mechanism into the deep learning model and develop an end-to-end solution driven by data. Our comprehensive experiments using various matrices and benchmarks highlight the superior performance of mmPose-FK, especially when compared to our previous research methods. The proposed method provides more accurate pose estimation and ensures increased stability and consistency, which underscores the continuous improvement of our methodology, showcasing superior capabilities over its antecedents. Moreover, the model can output joint rotations and human bone lengths, which could be further utilized for various applications such as gait parameter analysis and height estimation. This makes mmPose-FK a highly promising solution for a wide range of applications in the field of human pose estimation and beyond.

Long-Travel 3-PRR Parallel Platform Based on Biomimetic Variable-Diameter Helical Flexible Hinges.

Technological advancements across various sectors are driving a growing demand for large-scale three-degree-of-freedom micro-nano positioning platforms, with substantial pressure to reduce footprints while enhancing motion range and accuracy. This study proposes a three-prismatic-revolute-revolute (3-PRR) parallel mechanism based on biomimetic variable-diameter helical flexible hinges. The resulting platform achieves high-precision planar motion along the X- and Y-axes, a centimeter-level translation range, and a rotational range of 35° around the Z-axis by integrating six variable-diameter flexible helical hinges that serve as rotational joints when actuated by three miniature linear servo drives. The drives are directly connected to the moving platform, thereby enhancing the compactness of the system. A kinematic model of the motion platform was established, and the accuracy and effectiveness of the forward and inverse kinematic solutions were validated using finite element analysis. Finally, a prototype of the 3-PRR parallel platform was fabricated, and its kinematic performance was experimentally verified visually for improved endpoint displacement detection. The assessment results revealed a maximum displacement error of 9.5% and confirmed that, judging by its favorable workspace-to-footprint ratio, the final system is significantly more compact than those reported in the literature.

Non-synchronous deformation under shot peening post-treatment of SUS304 bar-plate rotary friction weld generates non-monotonic evolution on material and fatigue property

Shot peening post-treatment was conducted at SUS304 austenite steel bar-plate rotary friction welding joint with fatigue property deterioration from welding flash. along the shotting intensity increasing, non-synchronous deformation of the plate and flash resulted in non-monotonically evolution of local microstructure, residual stresses, and make the fatigue life increased to flash-removed joint level.