Kinematic Analysis Research Articles

X-Ray Fluoroscopy-Based Kinematic Analysis of Quadrupedal Locomotion in Slow and Fast Fatigue-Resistant Motor Neuron-Deleted Mice.

VAChT-Cre is a transgenic mouse line targeting slow-twitch fatigue-resistant and fast-twitch fatigue-resistant motor neurons that innervate oxidative type I and type IIa muscle fibers. To ablate these neurons, VAChT-Cre mice were crossbred with NSE-DTA mice, leading to the expression of diphtheria toxin A after Cre-mediated excision. The resulting VAChT-Cre;NSE-DTA mice exhibited motor deficits, abnormal locomotion, muscular atrophy, and tremor, making them a useful model for studying motor neuron physiology and pathology. In this study, we conducted a kinematic analysis to examine their abnormal locomotor phenotype. The quadrupedal walking of VAChT-Cre;NSE-DTA and control mice along a 500 mm acrylic tunnel was analyzed using an X-ray fluoroscopic system. Stride duration, stride length, footfall patterns, and limb and trunk kinematics were quantified and compared between the two groups. Our results demonstrated that VAChT-Cre;NSE-DTA mice walked more slowly than control mice (99.2 ± 43.5 mm/s vs. 120.5 ± 27.0 mm/s) and had a longer cycle duration (0.54 ± 0.19 s vs. 0.41 ± 0.09 s). In addition, the hindlimb was comparatively more flexed during the stance phase, the trunk was more rounded and humpbacked, and the cervix was lower in VAChT-Cre;NSE-DTA mice than in the control mice during locomotion. These characteristic differences in the gait kinematics might be attributed to a malfunctioning of the motor units with slow-twitch fatigue-resistant and fast-twitch fatigue-resistant types in VAChT-Cre;NSE-DTA mice. The basic description of the locomotor characteristics of this transgenic mouse line may serve as a basis for future comparative analyses.

Investigation and optimization of parameters for bidirectional composite vibratory finishing of gears

ABSTRACT To meet the core requirements for uniform and efficient finishing of high-precision gears, a bidirectional composite vibratory finishing (BCVF) process was introduced. The influence of motion parameters (gear rotational speed n, vibration frequency f x and f z , vibration amplitude A x and A z , vibration phase difference ψ), process parameters (media loading height H, gear installation position h), gear parameters and container geometric parameters (cross-sectional shape, size L x × L y ) on the finishing effect was investigated by kinematic analysis and discrete element simulation (DEM). On this basis, the parameters with significant influence were selected and further optimized by gray relational analysis (GRA). Numerical simulations were carried out by orthogonal design, taking the cumulative contact energy and distribution uniformity on gear surface as evaluation indicators for multi-objective optimization. The results indicated that the affecting significance on comprehensive performance was ranked as f x > f z > A x > A z . Besides, the optimal parameter combination was obtained.

Reconstructing active tectonics from land–sea correlations based on cross‐interpretation of core and seismic data for the Tyrrhenian coastal segment in southern Italy

AbstractThe current setting of most Tyrrhenian coastal plains in central‐southern Italy is the result of the interaction between sedimentary inputs, tectonic movements, and sea level changes during the Quaternary. Based on a comprehensive review of data from the literature on the stratigraphic setting of the coastal plains of Volturno and Garigliano Rivers, and with the final output being a validated 3D geological model, this study provides new elements for improved definition of the chronological intervals of fault activity. Specifically, the ages of tectonic deformations and/or subsidence are crucial for future estimates of coastal hazards induced by both seismicity and coastal inundations. Our multidisciplinary approach includes (i) definition of the Late Quaternary sedimentary architecture by revision of a large amount of core data, (ii) acquisition of offshore seismic reflection data and their correlation with sedimentary bodies of the coastal plains, and (iii) structural analysis of the main faults. These investigations were conducted on the marine segment offshore Mount Massico and on contiguous portions of the Volturno and Garigliano alluvial–coastal plains. The acquisition of seismic and core data enabled the definition of the sedimentary architecture of the coastal sectors of the plains. The Mt. Massico ridge (northern Campania), comprising Mesozoic–Cenozoic units of the orogenic chain and morphologically separating the two plains, was the subject of mesostructural analysis of fault orientation and kinematics. The seismic lines were calibrated correctly using two close stratigraphic core logs from the Garigliano Plain. The identification of correlatable and/or coeval stratigraphic/seismic units reveals land–sea correlations. These units are clearly affected by recent faulting expressed by complex deformation patterns, such as flower structures and strike‐slip faults.

Biomechanical analysis of kinematics in the single whip movement of Tai Chi using video imaging

“Single whip” is a typical movement in Tai Chi, and the study of its kinematics has important practical value for better understanding the laws and characteristics of Tai Chi movements. This study divided 30 Tai Chi practitioners into two groups based on their skill level: an excellent group and a beginner group. The Vicon motion capture system and a three-dimensional force platform were used to obtain kinematic data. Differences in movements between the two groups at various stages were compared. The results showed that the excellent group took longer in stages one and three, but shorter in stage two. In stage one, the left knee joint angle of the excellent group was 95.45° ± 16.02°, while the right knee and left hip joint angles were larger (148.62° ± 12.84° and 133.55° ± 18.61°). In stage two, the angles of the right knee, left ankle, and right ankle joints of the excellent group were significantly smaller than those of the beginner group. In stage three, the angle of the right elbow joint of the excellent group was larger (154.26° ± 12.06°), while the angles of the right wrist angle and the left and right ankle joints were significantly smaller than those of the beginner group (p < 0.05). In terms of vertical displacement of the center of gravity, the excellent group exhibited less fluctuation and significantly lower dynamic stability in both anterior-posterior and medial-lateral directions compared to the beginner group (p < 0.05).

Kinematic Analysis of a Cam-Follower-Type Transplanting Mechanism for a 1.54 kW Biodegradable Potted Cabbage Transplanter

Widespread use of plastic seedling pots has been attributed to their light weight and durable characteristics. However, these pots have limitations in facilitating efficient root establishment. Recent studies indicate that biodegradable seedling pots not only enhance seedling resilience but are also environmentally sustainable through natural decomposition. This study presents a kinematic analysis of a cabbage transplanting mechanism specifically under development for biodegradable seedling pots, focusing on position, velocity, acceleration, and power. The optimization of link combinations within the transplanting mechanism was analyzed to enhance the transplantation process, focusing on achieving precise depth and spacing for potted seedlings. A kinematic model of the mechanism was developed and simulated using commercial mechanical design and simulation software, followed by validation through performance tests. The proposed transplanter comprised a four-bar-linkage mechanism consisting of a driving link, a driven link, a connecting link, and a guide bar. Simulation trials were conducted by varying the main arm link length while keeping machine forward speed and mechanism driving speed fixed. Results indicated that the optimal mechanism parameters included a driving link of 50 mm, a connecting arm of 120 mm, a guide bar of 120 mm, and an end-effector link of 220 mm. A dibbling hopper length of 153 mm was identified as the most effective for operation. With these recommended link lengths, validated velocities of the end hopper in the ‘X’ and ‘Y’ directions were 284 mm/s and 1379 mm/s, respectively, while corresponding accelerations were measured at 1241 mm/s2 and 8664 mm/s2. The driving power requirement was calculated to be 17.4 W. These findings suggest that the developed mechanism provides effective planting performance, evidenced by a high degree of seedling uprightness and minimal soil disturbance. This study supports the use of biodegradable pots in mechanized transplanting as a viable alternative to conventional plastic pots, with potential benefits for both agricultural efficiency and environmental sustainability.

Path planning for flexible needle based on both insertion mechanism kinematics and needle bending model.

Due to the limited operating space in the magnetic resonance (MR) environment, there is coupled motion in the insertion mechanism, which not only reduces the flexibility of the robot but also challenges the insertion path planning. Meanwhile, the path planning is also restricted by the bending rule of the flexible needle, thus the bending model of the needle is also essentially built. This paper proposes a path planner for the flexible needle based on both the coupled motion kinematics of the insertion robot and the bending model of the flexible needle. A kinematic analysis for the coupled motion of insertion robot is performed. And the bending model of flexible needle is established based on the needle-tissue interactions. The position and posture of the needle insertion at the entry point are obtained by the calculation of the target position and the analysis of the bending model. And the rotation or translation coordinates of each robot joint are calculated by the inverse kinematics of the insertion robot. Then the path planning based on the coupled kinematics and the bending model is realized. The insertion experiments were performed for each target of G1 and G2. The root mean square errors were 0.83 mm and 0.74 mm, and the maximum errors were 1.1 mm and 0.9 mm for G1 and G2, respectively. The experimental results show that the effectiveness and accuracy of the path planning can meet the requirements for a general minimally invasive surgery, so the proposed path planning algorithm is feasible. This study provides a new solution for the path planning of insertion robots for the minimally invasive surgery. This method can meet the insertion mechanism working within the limited operating space in the MR environment and has a high application value in future clinical medicine.

Yingde–Guangning Granitic Plutons Record Complex Tectonic Evolution During Paleozoic-Mesozoic: Implications for Gold Exploration in Western Guangdong, South China

Western Guangdong, a part of the South China Block, has a complex geological history characterized by significant magmatic, metamorphic, and tectonic activities. This dynamic geological past, particularly during the Mesozoic era, created favorable conditions for the formation of various mineral deposits, including Au, Ag, Cu, and Pb. This makes the region a key area for precious metal resources in China. Despite extensive metallogenic studies, detailed structural information for western Guangdong remains insufficient, highlighting the need for further investigation. Thus, effective delineation of deformation periods is crucial for revealing geodynamic history and understanding regional tectonic activities, which are extremely important for guiding mineral exploration. This work focuses on the outcrops of granitic plutons in the Yingde–Guangning area of western Guangdong to establish the structure–tectonic setting. The tectonic events likely shaped the widespread Paleozoic–Mesozoic granitic bodies, which record extensive information on regional tectonic evolution. To achieve the primary objective, systematic identification and kinematic analysis of the various stages of structural traces, such as foliations and joints, have been conducted. This research proposes, for the first time, that the western Guangdong area underwent four distinct tectonic stages: (1) Early Paleozoic NW-SE compression phase; (2) Triassic NE-SW compressional stress; (3) Jurassic NW-SE compressional force; and (4) Cretaceous NW-SE extension stage. In metallogenic terms, the NW-SE trending auriferous veins of the Yingde–Guangning region were mostly formed during the Triassic NE-SW compression stage, whereas the NE-SW trending vein-type gold mineralization developed during the tectonic regime transformation from Jurassic NW-SE compression to Cretaceous NW-SE extension. This research emphasizes that systematic tectonic geological studies of regional granites can effectively guide mineral prospecting.

Type synthesis, analysis, and prototyping of 4R1H mechanisms

Abstract The article introduces a novel class of 4R1H mechanisms, where 4R indicates four revolute joints and 1H indicates one helical joint. The paper starts with the type synthesis of these mechanisms, which involves combining two kinematic chains with planar and cylindrical motion types into a single closed-loop kinematic chain. If we fix any link in such a chain, we get a workable mechanism. The synthesis procedure considers two options for the relative arrangement of these two kinematic chains. Adding an H joint to the kinematic chain allows us to design mechanisms whose output link performs spatial motion. Using the proposed synthesis procedure, we develop a family of 4R1H mechanisms. Next, we choose one mechanism as a representative example and consider its mobility, singularity, kinematic, and dynamic analysis. Using screw theory, we confirm the mechanism has one degree of freedom and determine its singular configurations. Kinematic analysis provides closed-form expressions to calculate displacements, velocities, and accelerations of all the mechanism links. Dynamic analysis uses these results to compute the motor torque required for one motion cycle. To verify the suggested analytical algorithms and obtained results, we use computer-aided design tools, which allow us to develop virtual and physical prototypes.

Justifying the structure of the improved mechanism for manual control of motor vehicles’ pedals

Due to the challenging military situation in Ukraine, the demand for tailored and flexible pedal control systems for individuals with physical disabilities is especially important. Standard pedal configurations often fail to meet the specific needs of drivers with limited mobility, making vehicle operation both difficult and potentially unsafe. The development of specialized manual control devices, such as hand-operated pedals or adjustable foot controls, is crucial for ensuring that these drivers can manage their vehicles with accuracy and safety. Such innovations not only improve accessibility but also foster greater autonomy and inclusion, empowering disabled drivers to navigate the roads with confidence and ease. This article aims to review existing prototypes of manual control mechanisms for vehicle pedals and to develop an improved device that enables simultaneous control of three pedals – accelerator, brake, and clutch – with one hand. As a result of a patent review of several existing prototypes of control mechanisms, it was concluded that the vast majority of them provide control for only two pedals – the accelerator and brake. This means they can only be used in motor vehicles with automatic transmissions or electric cars. Only a few mechanisms were designed to control three pedals, but they required using both the driver’s hands, directly affecting driving safety. Therefore, improving existing designs of the mechanisms for controlling three pedals by transferring all control functions to one hand of a driver remains relevant. The research methodology involves the use of classical methods from the theory of mechanisms and machines to conduct the structural synthesis of an improved multi-link hinge-lever mechanism and its kinematic analysis, aimed at determining the main parameters of pedals’ movements in a vehicle under various control inputs from the driver’s hand. The results obtained can be utilized by researchers and engineers to enhance manual control mechanisms for vehicle pedals and in the practical implementation processes. The prospects for future research on this topic are in developing an experimental prototype of the control mechanism and its testing and adjustment for different vehicle modifications to improve running smoothness and driving comfort and safety.

Kinematic Analysis and Trajectory Planning Based on a Six-Axis Robotic Arm

Kinematic analysis and time-optimal trajectory planning are applied to the robot in order to enhance its operational efficiency and preserve its continuous, smooth running trajectory. In this paper, the robot kinematics model is established based on the D-H parametric method with the Daqi Elfin series E05 six-axis robot as the research object. After that, forward and inverse kinematic analysis is carried out. And the segmented polynomial interpolation trajectory planning model of robotic arm is optimized in time based on the improved particle swarm algorithm. And MATLAB robot toolbox is used to build the robotic arm simulation model. From there, the trajectory planning simulation experiments are performed. As well as the experimental results show that the improved particle swarm algorithm effectively reduces the trajectory planning time. In the simulation experiment the time is reduced by 40.78% compared to the initial setting. The effectiveness of the robotic arm is greatly increased by this research.

Design and Prototype Testing of a Smart SMA Actuator for UAV Foldable Tail Wings

The foldable tail wing system of UAVs offers advantages such as reducing the envelope size and improving storage space utilization. However, due to the compact tail wing space, achieving multi-modal locking and unlocking functionality presents significant challenges. This paper designs a new smart SMA actuator for the use of UAV foldable tail wings. The prototype testing demonstrated the advantages and engineering practicality of the actuator. The core content includes three main parts: thermomechanical testing of the SMA actuation performance, structural design of the actuator, and the fabrication and actuation testing of the prototype. The key parameters related to actuation performance, such as phase transformation temperature and actuation force, were determined through DSC and tensile testing. The geometric parameters of the tail wing were determined through kinetics and kinematic analyses. Through the linkage design of two kinematic pairs, the SMA actuator enables both the deployment and locking of the tail wing. The prototype testing results of the folding tail wing show that, after vibration and temperature variation tests, the SMA actuator is still able to output an actuation stroke of 2.15 mm within 20 ms. The SMA actuator integrates locking for both modes of the tail wing and unlocking during mode transitions, offering advantages such as fast response and minimal space requirements. It provides an effective solution tailored to the needs of the foldable tail wing system.

Neuroadaptive Control of a Continuum Robot for Finger Rehabilitation

This study has designed an easy-to-wear parallel continuum robot-based hand rehabilitation system that supports and enhances the finger’s flexion, extension, abduction, and adduction movements. The primary novelty of the proposed system lies in its ability to focus therapeutic exercises on a single joint, a feature not commonly found in existing rehabilitation robots. A kinematic model of the system was developed, and to perform both kinematic and dynamic analyses, a multibody model was constructed in the MATLAB Simulink environment. Joint angle control was implemented using a nominal controller, and to account for individual uncertainties in joint dynamics, a neuroadaptive controller was integrated with the nominal controller. This approach aims for the neural network architecture to learn these uncertainties during control iterations and incorporate them into the control, resulting in a robust controller. Thus, a model reference control approach was proposed for active and passive rehabilitation processes. The system model was tested in a simulation environment, and then all tests were repeated in the physical system. The simulation and real system results include the real system’s open-loop responses, nominal controller responses for each joint, responses, and the results for active, passive, and assistive control modes.

Applying closed-loop equations for kinematic analysis of an eight-bar walking mechanism

Bionic mechanisms are used in constructing robotic systems that perform complex tasks similar to the movement of animals. With advancements in scientific research and breakthroughs in simulation techniques and computational methods, the design of these systems has become increasingly detailed and refined. This paper proposes using the closed-loop method to analyze the operational characteristics of a wheelless walking mechanism designed to traverse complex terrains. In addition to evaluating fundamental factors affecting system operation, the study determines kinematic parameters such as leg trajectory, movement velocity, and tilt angle. The results demonstrate the effectiveness of numerical methods in analyzing and simulating real-world systems, thus extending the use of computational tools for analyzing similar linkages.

New constraints on the central mass contents of Omega Centauri from combined stellar kinematics and pulsar timing

We performed a combined analysis of stellar kinematics with line-of-sight accelerations of millisecond pulsars (MSPs) to probe the mass content of Omega Centauri (OC ). Our mass model includes the stellar mass distribution, a more concentrated mass component linked to the observed MSP population, a generic cluster of stellar remnants (assumed to be more concentrated than the stars and MSPs), and an intermediate-mass black hole (IMBH), allowing us to determine which of these is statistically preferred to account for these observations. We mass-modeled OC using the package GravSphere to solve the Jeans equations, including constraints in the form of proper motions, line-of-sight velocities, the surface density profile of the stars, the spatial distribution of MSPs, and the recently measured line-of-sight accelerations of a subset of these MSPs, self-consistently modeling their intrinsic spin-down. We explore the impact of different assumed centers of OC on our results and we infer the posterior distributions of the model parameters from the combined likelihood using the nested sampling package dynesty Our analysis favors an extended central mass of $ over an IMBH, setting a 3sigma upper limit on the IMBH mass of $6 We find that pulsar timing observations are an important additional constraint, favoring a central mass distribution that is $ 20<!PCT!>$ more massive and extended than implied by models that are constrained by the stellar kinematics alone. Finally, we find a 3sigma confidence level (CL) upper bound of $6 on the total mass traced by the MSPs, with the density profile following $ p (r) star (r)^ with $ 0.3,$ where $ star (r)$ is the stellar mass density and $ is the stellar velocity dispersion profile. This favors models in which MSPs form via stellar encounters, as in the leading paradigm whereby MSPs are the progeny of low-mass X-ray binaries. Our analysis demonstrates how combining stellar kinematics with MSP accelerations produces new constraints on mass models, shedding light on the presence or absence of IMBHs at the centers of globular clusters. Further, we provide the first validation of its kind where MSP positions are linked to their place of formation in globular clusters, which is in excellent agreement with the expectations of stellar encounter models of MSP formation. This sets a promising precedent amid the rapid growth in the number of observations and discoveries currently taking place in this field.

An Underactuated Dexterous Hand with Novel Bidirectional Self-Locking Joints for Multiple Fingertip Active Motion Trajectories

This paper proposes an underactuated dexterous hand with novel bidirectional self-locking joints (BSJs) that enable multiple fingertip motion trajectories. The BSJ design integrates a locking wheel, rack, finger side walls, and a self-holding electromagnetic actuator, combining rack-and-pinion transmission with friction self-locking principles. Building on the BSJ concept, an underactuated dexterous hand is developed. The study begins with an analysis of BSJ’s deviation angle, establishing the minimum deviation angle critical to its operation. A detailed mechanical model of a BSJ is formulated, and its parameters are quantitatively analyzed to determine a safety static friction coefficient (0.177). Five distinct finger motion modes are designed and kinematic analysis focuses on the index finger and the generation of 57 unique fingertip active motion trajectories. Experimental validation included single finger performance tests that confirmed the diversity of fingertip trajectories and the hand’s ability to withstand loading in both forward and reverse directions. Through envelope and precision grasping experiments, the dexterous hand demonstrated its adaptability and ability to grasp objects of various sizes and shapes, such as strawberries, apples, student ID cards, and water bottles. This capability underscores its potential for a wide range of applications, from prosthetic hands for rehabilitation, where precision and adaptability are key, to robotic hands in industrial automation, offering flexibility in diverse tasks.

Structural Design and Kinematic Analysis of Cable-Driven Soft Robot

Continuous robots have attracted more and more attention from the robotics community due to their high degree of flexibility and pliability, and have shown great potential for application in a variety of fields. With the continuous progress of material science, control technology, and artificial intelligence, the performance and application range of soft robotics have been further expanded, in which the cable drive has the advantages of large workspace, high flexibility, etc. The cable-driven soft robotic arm serves as an ultra-redundant robot that can operate in cramped and confined environments. In this paper, a cable-driven soft robot based on soft continuums and a cross gimbal is presented. The kinematics of the cable-driven soft robot is modeled and the mapping relations of the kinematics are solved by the D–H method and piecewise constant curvature, and the relations between the cable length, joint angle, and pose are further derived. Finally, the motion space of the cable-driven soft robot in the three-dimensional coordinate system is obtained by MATLAB2021b, and the single-segment soft body is simulated and analyzed using ADAMS to compare the theoretical data with the actual data and verify the reliability of this structure and method.

Kinematics Analysis and Oil Film Lubrication Characteristics in the Piston–Cylinder Interface of a Bent-Axis-Type Piston Motor

Hydraulic piston motors are characterized by their excellent starting performance, high transmission torque, good sealing performance, compact design, and lightweight. These attributes make them highly applicable in fields such as construction machinery and marine applications. With the advancement of hydraulic transmission technology, higher performance requirements have been set for hydraulic motors. While extensive research has been conducted on hydraulic pumps, studies focusing on the performance of hydraulic motors remain relatively limited. Therefore, this paper is novel in that, based on the motion and force conditions of the piston, it differs from previous research on swashplate-type machinery by considering the complex structure of the bent-axis motor; it employs a micro finite element method to analyze the oil film characteristics at the piston–cylinder interface in a bent-axis piston motor, the structural changes in the piston assembly in the bent-axis motor are comprehensively considered, and a fluid–structure coupling model for the piston–cylinder interface is established. The leakage and viscous friction power loss equations for the piston–cylinder interface are derived. Simulation analyses are conducted using MATLAB R2016a to reveal the variation patterns of leakage and viscous friction power loss under different operating conditions and structural parameters, providing valuable insights for the operation analysis, energy loss evaluation, structural design optimization, and engineering applications of bent-axis piston motors.

Effect of recording angle on accuracy of Kinovea-based kinematic gait analysis compared to three-dimensional motion analysis in healthy dogs: optimal at 90° recording angle

Abstract OBJECTIVE The goal of this study was to investigate the effect of recording angle on the accuracy of 2-D Kinovea-based kinematic motion analysis (KMA) compared to 3-D KMA in dogs. METHODS In this prospective study, 3-D marker-based KMA (VICON-Nexus, version 2.12.1, and Procalc, version 1.6; VICON Motion Systems Ltd) was performed on healthy dogs (body weight ≥ 20 kg) walking on a treadmill (study period: November 2022). Simultaneously, dogs were video-recorded by 3 smartphones (iPhone SE; Apple Inc) at 1.50 m distance and 45°, 90°, and 135° recording angles relative to the shoulder for Kinovea-based, angle-calibrated KMA. Shoulder, elbow, carpal, hip, stifle, and tarsal joint kinematics were calculated for 3 synchronized gait cycles. Each gait cycle was divided into 10 increments. The estimated difference between 3-D KMA and Kinovea was assessed using robust linear mixed-effects models. RESULTS 34 dogs were included. Differences of less than 5° between methods were considered reasonable. At a 45° recording angle, the estimated joint angle difference was < 5° for the carpus and hip during ≥ 5 of 10 gait cycle increments. At 90°, the difference was < 5° across all joints for ≥ 9 of 10 increments and at 135° was < 5° for the elbow, carpus, and hip for ≥ 7 of 10 increments. CONCLUSIONS Kinovea-based kinematics were most accurate when recorded at 90°. At 45°, Kinovea provided accurate data for the carpus and hip and at 135° for the elbow, carpus, and hip. CLINICAL RELEVANCE While angle-calibrated kinematic measurements can be accurate when using Kinovea for canine KMA, a 90° recording angle is preferable.

Inverse kinematics analysis of a wrist rehabilitation robot using artificial neural network and adaptive Neuro-Fuzzy inference system

This paper offers a comprehensive investigation into the forward and inverse kinematics of a wrist rehabilitation robot, utilizing the Denavit-Hartenberg method for forward kinematics (FK) and a geometric approach, as well as artificial neural networks (ANN) and adaptive Neuro-Fuzzy inference systems (ANFIS) for inverse kinematics (IK) analysis. While the geometric method entails precise parameter measurements and faces uncertainties, ANN and ANFIS are explored as potential remedies to enhance accuracy and robustness. Evaluating 11 different training functions sourced from existing literature, our study conducts a thorough assessment of their performance within an ANN network. We aim to pinpoint the most suitable training function for achieving optimal IK solutions in the context of a wrist rehabilitation robotic. Additionally, the ANFIS model, trained using Fuzzy C-Means (FCM), sets itself apart from Grid Partitioning (GP) and Subtractive Clustering (SC). Among the ANN training functions, Bayesian regularization with 5 hidden layers emerges as the most effective, yielding low root mean square error (RMSE) values of 0.003, 0.004, and 0.007 degrees for pronation/supination (P/S), abduction/adduction (AB/AD), and flexion/extension (F/E), respectively. Conversely, ANFIS, trained with FCM, demonstrates satisfactory yet less precise results, with RMSE values of 0.191, 0.082, and 0.165 degrees for P/S, AB/AD, and F/E, respectively. Despite its adequacy, ANFIS trails behind ANN, showcasing RMSE reductions of 98.4%, 95.1%, and 95.7% for P/S, AB/AD, and F/E angles, respectively. This study contributes to leveraging ANN and ANFIS for IK analysis in wrist rehabilitation robotics, highlighting the efficacy of ANN, particularly when employing Bayesian regularization, to enhance accuracy.

Study of a Companion Trajectory Kinematics Analysis Method for the Five-Blade Rotor Swing Scraper Pump

This paper proposes a five-blade rotor swing scraper pump (FRSSP) to overcome traditional volumetric pumps’ drawbacks, such as poor sealing performance, low volumetric efficiency, and complex structure. This pump employs a rotating cam-swing scraper mechanism to achieve fluid intake and discharge. The FRSSP is compact in structure, self-sealing, and highly efficient in volumetric utilization, offering promising applications. A companion trajectory kinematic analysis method of the FRSSP is proposed. The polar coordinate equation of the companion trajectory is derived from the profile equation of the five-blade rotor cam. Based on this trajectory, a kinematic model of the scraper pump is established, resulting in the kinematic equations for the swing angle of the scraper, the pressure angle of the scraper, the rotation angle of the rotor, the angular velocity of the scraper, and the angular acceleration of the scraper. The kinematics of the FRSSP were simulated and validated using ADAMS. Comparing the results of theoretical calculations and simulation reveals that the error in the scraper swing angle is 1.85%, the maximum error in the scraper angular velocity is 4.93%, and the maximum error in the scraper angular acceleration is 2.47%, confirming the accuracy of the kinematic analysis method. A sensitivity analysis was performed on the kinematic research method for companion trajectories. After modifying the dimensions of key components in the scraper pump, the discrepancies between theoretical calculations and simulation results were within 5%, confirming the accuracy and robustness of the method. Flow field simulation analysis and experimental tests on the scraper pump revealed that the deviation between the simulated and experimental outlet flow rates was less than 5%, validating the feasibility of the pump’s structural principles and the reliability of the simulations. Furthermore, these findings indirectly affirmed the correctness of the companion trajectory kinematic analysis method.