Values Of Kinematic Parameters Research Articles

Analysis of the third class mechanism using the modeling method in the Mathcad software environment

Purpose. To carry out a kinematic analysis of a flat twelve-link hinged mechanism with three leading links, the basis of which is a structural group of links of the third class of the fourth order with rotational kinematic pairs, which is used in technological equipment. Methodology. The kinematic study of a flat complex mechanism of the third class with three leading links was performed using the mathematical modeling method in the Mathcad software environment. Findings. Using the method of mathematical modeling, the mechanism was presented in the form of free vectors built on its links, for which, taking into account the presence of three leading links, three vector contours were selected, which made it possible to draw up a system of vector equations of their closedness with further solving by a numerical method in the Mathcad software environment. The functions of the rotation angles of the mechanism links, their angular velocities and accelerations were obtained in analytical and graphical form depending on the rotation angle of the first driving crank of the mechanism, the calculation of the angular velocities and accelerations of all the driven links of the mechanism was performed. Originality. A sequence was developed and a kinematic study of a complex planar mechanism of the third class with three leading links was done, the basis of which is a structural group of links of the third class of the fourth order. Schematic modeling of the mechanism with three leading links was performed, a visualization schedule of its kinematic scheme was built, and a valid version of its assembly was obtained from many possible ones, for which the values of kinematic parameters of all its links were determined. Practical value. An analysis of the effect of the kinematic parameters of the three leading links of the third-class mechanism on the movement of the working body of the technological equipment was carried out. From the analysis of the obtained research results for the cycle of the mechanism the reason was found for the incomplete technological stoppage of the link, which should provide the working body of the machine for the required period of time. Recommendations of the elimination were made to identify the deficiency and proposals for the need to improve the drive of this equipment.

Investigation of the efficacy of different cryoprotectants in the freezing of testicular tissue and epididymal sperm: Spermatological parameters, tissue viability and PARP-1 gene expression

The presented study covers testicular tissue and epididymal spermatozoa cryopreservation processes in bulls and aims to investigate the effects of these applications on spermatological parameters, cell viability in testicular tissue, and the expression of the PARP-1 gene, a DNA repair enzyme. Testes of 20 bulls over 2 years old, slaughtered in a slaughterhouse, were used in the study. After spermatological evaluations, the semen obtained from the cauda epididymis was frozen in liquid nitrogen vapor according to the straw method and stored in liquid nitrogen (−196 °C). Testicular tissue pieces obtained from the testicles were frozen by the slow freezing method in cryotubes in diluents containing Dimethylsulfoxide (DMSO) and Ethylene Glycol (EG) cryoprotectants and stored in liquid nitrogen (−196 °C). The total motility (TM) (85.89 ± 12.83 %), progressive motility (PM) (54.02 ± 15.77 %), and kinematic parameter values of fresh sperm were significantly higher compared to the TM (57.62 ± 13.13 %), PM (29.60 ± 10.76 %), and kinematic parameter values after thawing (P < 0.05). Significant decreases in plasma membrane integrity (PMI) and viability and an increase in chromatin condensation and morphological disorders in the head, middle part, and tail regions were observed in post-thaw semen samples (P < 0.05). When the effects of DMSO and EG on cell viability after thaw in frozen testicular tissue were evaluated, it was observed that the cell viability values of testicular tissues frozen with EG (45.70 ± 10.00) were statistically significantly lower than those frozen with DMSO (51.20 ± 7.70) (P < 0.05). When the effects of both cryoprotectants on gene expression in tissue and semen samples were examined, it was determined that gene expression increased on average 0.19 ± 0.27 times in the tissue samples in the DMSO group compared to fresh tissue samples and 0.17 ± 0.19 times in the tissue samples in the EG group. It was determined that gene expression levels increased by an average of 1.20 ± 1.08 times in post-thaw epididymal spermatozoa samples compared to fresh semen samples. The results show that cryopreservation can activate cellular repair mechanisms by stimulating PARP-1 gene expression and affect gene expression by activating specific pathways in tissues and cells.

Effect of Water Exposed to Electric Current on Gamete Quality of Rainbow Trout (Oncorhynchus mykiss) and Water Parameters

Electrofishing is a widely preferred method in freshwater. Freshwater conducts electric current at low levels. Therefore, a relatively high voltage electric current is applied in these waters. In this study, the effects of changes in the structure of the water after the electric current applied to the water on gamete quality and embryo-larvae survival rates were investigated. Water samples were collected from the central region of the tank (N), as well as from the positive (+) and negative (-) poles following the application of an electric current to the well water at 165 volts and 3 mA for durations of 15 and 30 minutes. Sperm kinematic velocity parameters, fertilization and hatching rates were determined to be at the highest level in the group where electric current was applied for 30 minutes and water samples were taken from the middle of the tank, 30 (N), were used (P&lt;0.05). Furthermore, it was observed that the Chemical Oxygen Demand value was one of the values lowest in the groups where sperm motility results were found to be the highest (P&lt;0.05). Regardless of the duration of electric current application, it was found that the dissolved oxygen value of the water samples collected from the positive poles was similar to the control group, but higher than the negative poles. In conclusion, the application of electric current resulted in variations in both the sperm kinematic parameter values and the water parameters among the samples collected from different poles. However, there was no statistically significant difference in fertilization and hatching rates between the groups (P&gt;0.05).

What information on mechanical parameters can a polynomial model tell about the 100 ​m sprint

In this paper for the first time, a simple procedure allowing to obtain all important parameters of the 100 ​m run based only on the measured values for the distance S from the start line and expired time t, was summarized. An example for testing the proposed model were the results for segment values for S and t for elite sprinters, male: C. Lewis, M. Green and U. Bolt, and female: F. Griffith-Jоyner, F. Ashford and H. Drecksler. The distance was approximated by a third order polynomial function, S ​= ​f(t), which is easily fitted from the split (segment) times. This function is a mathematical model which enables, via a standard mathematical treatment, the ability to obtain the equations for determining the point of the maximal sprinter velocity, vmax, corresponding to vanishing acceleration, its distance from the start line (Smax) and corresponding time moment (tmax). The function provides direct reading of the initial velocity (vo) as well as finding the expressions for the sprinter instantaneous velocity (vt) and acceleration (at). It also provides the initial acceleration, enabling the determination the forces acting at the beginning of the run. The results obtained justified the proposed approach for a universal and practical preparation tool and also showed that there were no significant differences in the values of kinematical parameters between analyzed male and female sprinters.

The Difference in Subpopulation Structures in Sex-Sorted and Non-Sorted Semen by Discriminant Analysis of Bull Sperm Motility Data Collected by a Computer-Assisted Sperm Analysis System

We examined the motility characteristics of sperm from sex-sorted bull semen as a model for low-quality (expected low conception rate) sperm compared to that of sperm from non-sorted semen (expected average conception rate) using cluster analysis followed by discriminant analysis. The results indicated that sex-sorted semen contained sperm with hyperactivation-like motility as the main subpopulation immediately after thawing, and this subpopulation decreased after 2 h of incubation. The main subpopulation in the non-sorted semen had progressive motility that was maintained during incubation. A conventional comparison of the mean values of kinematic parameters could not distinguish the samples. In conclusion, discriminant analysis using data from a cluster analysis of motile sperm may accurately describe differences in the structures of sperm motility subpopulations between low and normal fertility semen.

SIMULATION OF HYPERSURFACES BASED ON THE DATABASE OF KINEMATIC PARAMETERS OF THE ANDROID ROBOT MECHANISM

The paper proposes a method that allows the modernization of the methodology for constructing manipulator movements according to the velocity vector, which makes it possible to exclude the occurrence of deadlocks in the process of computer simulation of movements. The developed algorithm is based on the use of a database characterizing the values of kinematic parameters that set the permissible instantaneous states of the manipulator mechanism at its various positions. A graphical representation of the hypersurface reflecting the relationship of these kinematic parameters from the values of generalized coordinates is performed. Based on this a method for determining kinematic parameters in the synthesis of movements of manipulator mechanisms in organized environments is proposed, which reduces the calculation time of intermediate configurations on a given trajectory of the output link and partially eliminates the occurrence of deadlocks. The results of the computer simulation of the movement of the arm and torso of the android robot on the criterion of minimization of the volume of movement, as well as movement taking into account the position of the forbidden zone with the overcoming of the deadlock situation are presented. The conducted studies can be used in the development of information and control complexes of mobile objects, in particular in the development of intelligent control systems for autonomously functioning robots in organized environments.

Study on Redundancy in Robot Kinematic Parameter Identification

The robot kinematic error model may include redundant parameters, which require removal prior to the identification of kinematic parameters to ensure the accuracy and stability of such. Traditionally, the redundant parameters are determined by the numerical analysis. This paper presents an analytical method to determine the identifiable kinematic parameters for serial-robot calibration under various identification conditions. Among various kinematic models of robots, the DH (Denavit-Hartenberg) model is the most commonly used, so the analysis of redundant parameters is based on the DH error model. The correlation between the columns of the Jacobian matrix is analyzed by theoretical methods, resulting in the linear relationship between these columns. The redundant error parameters and the linear independent parameters after removing redundancies from robots with different measurement conditions and different configurations are clearly given. Thus, the redundant parameters can be easily determined based on the values of kinematic parameters, which facilitates the determination of the non-redundant kinematic calibration model. In addition, the physical meanings of redundant parameters are also elaborated, which can reveal the inherent principle of the error parameters&#x2019; linear correlation. Finally, the parameter identification simulation experiment shows that the identification results, after removing the redundant parameters, all converge to the true values when the random noise is not considered, which verifies the correctness of the parameter redundancy analysis results. In the case of considering random noise, the non-redundant parameter identification has better convergence than the full parameter identification. This study can provide theoretical and application references for robot kinematic calibration.

Исследование кинематических параметров андроидного робота при автоматизированном синтезе движений по вектору скоростей

The modernization of the method of synthesis of motions of manipulators by speed vector allows to exclude motions the emergence of dead ends in the process of computer simulation. The developed algorithm is based on the use of a database characterising the values of kinematic parameters that specify the permissible instantaneous states of the mechanism of the manipulator at different positions. The graphical representation of the hypersurface of the reflective relationship of the specified parameters from the values of the generalized coordinates is made. On the basis of this, a method for determining the above kinematic parameters is proposed, which makes it possible to reduce the time for calculating intermediate configurations on a given trajectory of the output link and to eliminate the occurrence of deadlock situations.

Energy Mechanisms of Free Vibrations and Resonance in Elastic Bodies

The scientific novelty of this work is determined by the rationale for the participation in transformations, along with the kinetic energy of particles, of four types of elastic energy, identified by the peculiarities of their phase changes in the oscillation process. Two types are converted into kinetic energy, while the other two types change the deformed state of particles in accordance with the equations of motion due to internal sources. The result is obtained based on the use of the superposition principle in the space of Lagrange variables with the imposition of forced and free oscillations, as well as a new model of mechanics based on the concepts of space, time, and energy with a new scale of average stresses that takes into account the energy of particles in the initial state. In such a model of mechanics, a generalized measure of the elastic energy of particles is a quadratic invariant of asymmetric tensor whose components are partial derivatives of Euler variables with respect to Lagrange variables. The concept of kinematic energy parameters is introduced, which differ from the corresponding volumetric energy densities by a multiplier equal to the modulus of elasticity, which is directly proportional to the density and heat capacity of the material, and inversely proportional to the volumetric compression coefficient. Comparison of the values of kinematic parameters shows that most of the energy required for oscillations is associated with the deformation of particles and comes from internal sources. The mechanisms of transformation of forced vibrations into their own for transverse, torsional, and longitudinal vibrations are considered, as well as the occurrence of resonance when free and forced vibrations are superimposed with the same or a similar frequency. The formation of a new free wave after each cycle of external influences with an increase in amplitude, which occurs mainly due to internal, and not external, energy sources is justified.

Does posture explain the kinematic differences in a grounded running gait between male and female Svalbard rock ptarmigan (Lagopus muta hyperborea) moving on snow?

The majority of locomotor research is conducted on treadmills and few studies attempt to understand the differences between this and animals moving in the wild. For example, animals may adjust their gait kinematics or limb posture, to a more compliant limb, to increase stability of locomotion to prevent limb failure or falling on different substrates. Here, using video recordings, we compared locomotor parameters (speed range, stride length, stride frequency, stance duration, swing duration and duty factor) of female Svalbard rock ptarmigan (Lagopus muta hyperborea) moving in the wild over snow to previous treadmill-based research. We also compared the absolute and body size (body mass and limb length)-corrected values of kinematic parameters to published data from males to look for any sex differences across walking and grounded running gaits. Our findings indicate that the kinematics of locomotion are largely conserved between the field and laboratory in that none of the female gaits were drastically affected by moving over snow, except for a prolonged swing phase at very slow walking speeds, likely due to toe dragging. Comparisons between the sexes indicate that the differences observed during a walking gait are likely due to body size. However, sexual dimorphism in body size could not explain the disparate grounded running kinematics of the female and male ptarmigan, which might be linked to a more crouched posture in females. Our findings provide insight into how males and females moving in situ may use different strategies to alleviate the effects of a variable substrate.

EVALUATION OF THE INFLUENCE OF VELOCITY ROTOR REGIMES ON ELECTRICITY CONSUMPTION DRIVED BY A VIBRATION DISC CRUSHER

Among a number of methods for intensifying the process of grinding grain material in the technology of compound feed preparation, one of the most promising can be considered the use of a vibration field, which contributes to the formation of optimal conditions for the timely withdrawal of the finished product from the grinding zone and ensures self-cleaning of the separation surfaces from the remnants of the crushed product (especially when using non-food classes grain), thereby ensuring the maximum throughput of the machine. Given that for grinding in feed production mainly use impact machines, which are adapted to the destruction of solid and at the same time fragile objects, as well as the economic feasibility of processing substandard feed grain, which has completely opposite physical and mechanical characteristics. scheme of vibrating-rotary disk crusher. The essence of the development is to provide a combined force on the material, namely, due to the rotational and vibratory motion of the impact elements of the crusher, a combination of impact destruction and cutting material, which will process both hard and wet material without significantly reducing equipment throughput. In addition, the oscillating mode of the working chamber and, as a consequence, the separation surface will facilitate the timely removal of the finished product from the grinding zone. The next stage of creating a vibrating-rotary crusher, which precedes the design and constructive implementation is to perform theoretical calculations of its parameters, including using the methods of mathematical modeling. Thus, in order to achieve high efficiency of the process of grinding feed by the designed machine, theoretical studies of the relationship between the values of kinematic parameters of the executive bodies and electricity consumption to drive them, the main results of which are presented in the article.

Abstract WP180: Measuring Tissue Motion During Carotid Endarterectomy Using Video-based Analyses

Background: During carotid endarterectomies (CEA), perioperative stroke and cranial or cervical nerve injuries are the most common major complications. Many experts have emphasized the importance of careful and gentle manipulation around carotid plaques. However, there have been no methodological assessments that quantitatively measure ‘gentleness’. This study was aimed to propose a novel metric for gentle surgical maneuvers during CEA. Methods: Using surgical video-based motion software, the motion of the carotid artery around plaque was analyzed and quantified during a CEA. Kinematic parameters (minimum and maximum acceleration, and maximum and mean velocity) were compared among the surgical tasks and techniques, as well as between novice and expert surgeons. Results: The surgical tasks of dissecting the common carotid artery, passing the proximal vessel loops, and ligating vessels showed the highest absolute values of kinematic parameters. Dissections perpendicular to the line of the internal carotid artery tended to show higher kinematic parameters than those in the parallel direction, with blunt dissections typically higher than sharp dissections. The kinematic parameters of novice surgeons were significantly higher than those of experts, and receiver operating curve analysis showed a strong discriminative power. The kinematic parameters in the case of postoperative ischemic stroke also showed the highest absolute values. Conclusions: This study shows that tissue motion parameters could be a novel and feasible surrogate marker for the objective assessment on the ‘gentleness’ of surgical performance in CEA. Such an objective measurement might be applicable towards enhancing surgical education and risk management.

A Pilot Study on Measuring Tissue Motion During Carotid Surgery Using Video‐Based Analyses for the Objective Assessment of Surgical Performance

The 'gentle' handling of tissue (i.e., 'respect for tissue') is a fundamental aspect of surgical performance and learning. To date, there have been no methodological assessments that quantitatively measure 'gentleness.' Therefore, the aims of this study were (1) to propose a novel metric for gentle surgical maneuvers, (2) to validate the feasibility of this methodology, and (3) to explore safer surgical techniques through this methodology. Using surgical video-based motion software, the motion of the carotid artery around plaque was analyzed and quantified during a carotid endarterectomy. Kinematic parameters (minimum and maximum acceleration, and maximum and mean velocity) were compared among the surgical tasks and techniques, as well as between novice and expert surgeons. The surgical tasks of dissecting the common carotid artery, passing the proximal vessel loops, and ligating vessels showed the highest absolute values of kinematic parameters. Dissections perpendicular to the line of the internal carotid artery tended to show higher kinematic parameters than those in the parallel direction, with blunt dissections typically higher than sharp dissections. The kinematic parameters of novice surgeons were significantly higher than those of experts, and receiver operating curve analysis showed a strong discriminative power. This study shows that tissue motion parameters could be a novel and feasible surrogate marker for the objective assessment on the 'gentleness' of surgical performance. Future studies should be performed to further elucidate the relationship on the direct correlation between tissue kinematic data and clinical outcomes or surgical adverse events.

An inverse kinematic model of the human training centrifuge motion simulator

The paper presents an inverse kinematic model for a centrifuge motion simulator used to verify newly defined absolute acceleration profiles. The modelling is concerned with a human training centrifuge with three degrees of freedom. The values of kinematic parameters have been obtained for this three-jointed manipulator. Validation of the developed model has been performed by comparing the results obtained from the centrifuge motion simulator with the results of numerical simulations. The simulation revealed that the inverse kinematic model enabled calculation of the angular displacement, velocity and acceleration of the links that are needed for the given linear acceleration of the simulator cabin.

Non-conventional approach in single-sided lapping process: kinematic analysis and parameters optimization

The lapping process is strongly affected by a number of input parameters. One of the fundamental mechanical processes in lapping is the abrasive effect of particles. In order to examine the influence of the kinematic parameters on the lapping uniformity of unconventional single-sided machine, numerical simulations of particles sliding trajectories are performed. Changing the kinematic parameters, e.g., rotational velocities or position of the conditioning rings together with the workpieces can be used for correcting the profile of an active surface of the lap. This paper provides a basic guide to the kinematic parameter settings of single-sided lapping process. Furthermore, an unconventional single-sided lapping system, where a conditioning ring performs additional motion during the machining, is described. Simulation results show that the rotational speed ratio of the conditioning ring to the lapping plate k1 and the period ratio of the reciprocating motion to the lapping plate rotary motion k2 represent the relationships among the three basic motions of unconventional lapping systems and are major factors affecting trajectory distribution. Material removal rate and trajectory density parameter are proposed to optimize the kinematic parameters for better uniformity of lapping plate wear. The preferred kinematic parameter values for single-sided lapping system with reciprocating motions and the assumed size of the machine are k1 = 0, 78 and k2 = 2. The general results were validated on a specially designed test stand.

Kinematic optimization of a flapping foil power generator using a multi-fidelity evolutionary algorithm

Abstract For hydrodynamic optimization using computational fluid dynamics methods, the high computational cost impedes the use of evolutionary algorithms since they require evaluation of numerous solutions. In this paper, a multi-fidelity evolutionary algorithm, implemented with a dynamic stall model and a modified discrete vortex method, is used to find values of kinematic parameters for high energy extraction performance from a flapping foil. A single objective problem with two variables is first used to illustrate the benefits of the multi fidelity optimization strategy. Then the efficiency and the power output characterized by five design variables are optimized by the multi-fidelity evolutionary algorithm. The nondominated solutions obtained from the exercise are evaluated by the lattice Boltzmann method for detailed analysis. The results show that despite the use of low fidelity models and limited budget of computational resources, the multi-fidelity strategy is capable of finding kinematic conditions suitable for high energy extraction performance from a flapping foil. In addition, detailed flow analysis reveals that high energy extraction performance is associated with the detachment of the leading edge vortex near stroke reversal, resulting in a horseshoe-shaped vorticity wake with a width approximating the swept distance of the foil behind the turbine plane.

Calculation of the resistance forces from the interaction of blade teeth cutting edges with the soil

The methods of calculation of the resistance forces from the interaction of blade teeth cutting edges with the soil and their torque about the center of the disk are proposed. The reaction of soil to a blade toothed is replaced by the resultant force applied to its toe. The resultant direction is taken to be opposite to the velocity vector of the blade toe. So soil reactions to a toothed disk depend on kinematic parameter (the ratio of peripheral disk speed to forward speed). It is shown that the total vertical and horizontal reactions of the soil to the blade teeth can be obtained by analytical or graphical addition. The developed mathematical model of the interaction of blade teeth cutting edges with the soil allows to determine the soil reaction to a toothed disk and the moment of soil resistance to cutting by a toothed disk as periodic functions of its rotation angle. It allows to identify ways of reducing the power capacity of a toothed disk. The horizontal component of soil reaction to a toothed disk is the driven force at kinematic parameter values greater than 1.2. Since the maximal driven disk force and the moment of soil resistance to cutting increase with deceleration with increase in kinematic parameter, it is profitable to use operation modes with its less values.

Formation of flat surfaces of optoelectronic components in diamond polishing

Based on the physical-statistical model of formation of workpiece material debris particles in diamond polishing, an analysis of removal rate and form accuracy has been performed for flat surfaces of optoelectronic components made of quartz, aluminum nitride, and gallium nitride. The most efficient values of kinematic parameters of machine tool setting have been defined to achieve the required shape-generation accuracy. The paper provides some findings of the experimental verification of calculated data on the removal rate in polishing and the form deviation of the machined surfaces.

Numerical model of Fanuc AM100iB robot

The article presents a numerical model of Fanuc AM 100iB robot, prepared in the form of a block diagram in Simulink software, using the SimMechanics toolbox. The main task of the numerical model of Fanuc AM 100iB robot is to calculate the value of torques putting a load on motor shafts, and to calculate the values of kinematic parameters of the robot's arms in real time and in interactive mode. The values and format of torques putting a load on subsequent joints, and then on the motor shafts, resulted from the effect of the simultaneous action of all torques and the delay, resulting from the implementation of numerical calculations in real time. The numerical model developed is a result of design focused on recreating the effects of simultaneous action of all these factors, which are present in the actual drives and affect the consumption of electricity. A very important criterion, taken into account when designing the model, was also its computational efficiency. In addition, the model was used to visualise the work of the tested machine in three-dimensional space.

Trajectory Planning for Reconfigurable Industrial Robots Designed to Operate in a High Precision Manufacturing Industry

This paper presents an algorithm for an automated planning of time-jerk optimal trajectories on a reconfigurable robot with an anthropomorphic structure. The trajectory planning algorithm is designed to provide reachable input set-points for the reconfigurable control system to accommodate not only changes in task objectives but also various reconfigurations of the robot kinematic structure and motion behavior adaptation in response to operational constraints. Firstly, appropriate reference frames are defined on the robotic modules and the position and orientation of the end effector in the Cartesian space is dynamically generated through a reconfigurable forward kinematics module. Secondly, through an iterative inverse kinematic method, the robot configuration space for the start and goal destinations and the geometric path for every motion tasks are generated. Finally, the joint space trajectories with coordinated motion profiles are generated by incorporating the motion laws and joint kinematic parameter values. The general outcome of the algorithm is a trajectory plan of the robot joints expressed as a time history of the robot motion. The trajectories are dynamically generated to satisfy widely varying tasks, constraints and objectives aiming towards a fully reconfigurable control without any hardware or software adjustment.