Motion Machine Research Articles

Novel Gaussian Acceleration Profile for Smooth Jerk-Bounded Trajectories

Industrial machines regularly work at their limits causing excessive long-term vibrations that deteriorate their movement, stability, and precision. In this sense, reference profiles are able to reduce the detrimental vibration effects by manipulating the machine motion dynamics using predefined movement trajectories. Most of the approaches for lessening damages due to long-term machine vibrations are based on polynomial functions with high computational complexity and high resources demand. Hence, in this work, an innovative acceleration outline based on a Gaussian function is proposed for machine motion trajectories. The introduced strategy simplifies the position-profile estimation that works as reference for restraining the machine movements through the parameters that define its motion dynamics; thus, a smooth and continuous jerk contour is produced, which reduces vibrations and improves the machine stability. Exhaustive computer-based and real-time experimental comparisons of the introduced scheme produces a significantly lower maximum jerk value than any of the others. The assessment of the presented approach was performed utilizing the software Matlab (R2020a) on a PC with an Intel Core i7-6500U microprocessor at 2.5 GHz, with 16 GB in RAM and a 64-bit operating system.

In-situ acoustic monitoring of direct energy deposition process with deep learning-assisted signal denoising

In-situ monitoring is crucial for detecting process anomalies and ensuring part quality in additive manufacturing. Acoustic-based monitoring techniques offer extra benefits such as adjustable sensor setup and lower hardware costs. In the direct energy deposition (DED) process, acoustic signals generated by laser-material interactions carry information about underlying complex physical mechanisms such as melting, solidification, crack propagation, and pore formation. This paper presents a novel acoustic-based in-situ monitoring method for the DED process. The raw acoustic signal is made up of laser-material interaction sound as well as noise from machine movement, inert gas flow, and powder flow. A deep learning model is developed to build an end-to-end signal denoising framework to minimize environmental noise and extract the laser-material interaction sound. Audio equalization, bandpass filtering, and Harmonic-Percussive Source Separation algorithm are used to produce a cleaned laser-material interaction sound as the model's ground truth target. Acoustic data is collected from experiments using different DED machines, materials, and varied process parameters to train the deep learning model. The proposed deep learning-assisted signal denoising strategy lays the groundwork for acoustic-based in-situ defect detection of the DED process.

Методика вибору рушія для машин спеціального призначення

The ability to move on different types of soils is one of the main indicators of the efficiency of mobile vehicles in off-road conditions. The movement of such special mobile machines is carried out due to the interaction of the propulsion with the support surface. Therefore, significant reserves to increase productivity and reduce the cost of technological and transport works are laid in reducing energy consumption when the engine interacts with the surface. On the process of interaction of the wheel drive with the deformable support surface it is established that the parameters of this interaction depend on a number of factors: normal load, angular velocity and torque. In the General case, the parameters of interaction of each engine change when changing the mode of movement of the wheeled vehicle, and the ability to change the air pressure in the tires when driving on different support surfaces allows to increase the performance of the wheeled vehicle In the study of the caterpillar, it was found that the pitch of the caterpillar, the stiffness of the caterpillar, the angular stiffness of two adjacent tracks, reducing the pitch of the caterpillar chain, reducing the stiffness of the caterpillar, increasing the angular stiffness of two adjacent tracks, affect the efficiency of the machine. The scientific novelty of the study is to develop a method of choosing the engine of a special mobile machine that works off-road, in the process of its design. Wheel or crawler solutions will mainly determine the performance and efficiency of special purpose vehicles. The choice of engine for special mobile machines is based on a set of criteria. The criteria determine the importance of the implementation of the tasks in relation to the efficiency of functioning. Knowing the sowing capacity of the soil, and taking into account the possibility of movement of a particular special mobile machine depending on the type of soil, you can choose one or another type of engine.

Biomechanical Analysis of the Throwing Athlete and Its Impact on Return to Sport

Throwing sports remain a popular pastime and frequent source of musculoskeletal injuries, particularly those involving the shoulder and elbow. Biomechanical analyses of throwing athletes have identified pathomechanic factors that predispose throwers to injury or poor performance. These factors, or key performance indicators, are an ongoing topic of research, with the goals of improved injury prediction, prevention, and rehabilitation. Important key performance indicators in the literature to date include shoulder and elbow torque, shoulder rotation, kinetic chain function (as measured by trunk rotation timing and hip-shoulder separation), and lower-extremity mechanics (including stride characteristics). The current gold standard for biomechanical analysis of the throwing athlete involves marker-based 3-dimensional) video motion capture. Emerging technologies such as marker-less motion capture, wearable technology, and machine learning have the potential to further refine our understanding. This review will discuss the biomechanics of throwing, with particular attention to baseball pitching, while also delineating methods of modern throwing analysis, implications for clinical orthopaedic practice, and future areas of research interest. Level of EvidenceV, expert opinion.

Quay Contact Detection for Ships using Motion Sensors and Machine Learning

Detecting when and where contact with the quay appears is an important ability for ships undergoing a docking maneuver. The motion of the quay, environmental forces, and hydrodynamic effects caused by the interaction between the ship and the quay are all important factors that affect if a docking procedure succeeds or not. This paper studies how contact with the quay can be detected using conventional motion sensors. This includes sensor data from inertial measurement units, global navigation satellite systems, and estimates from an inertial navigation system. The contact detection task can be interpreted as a binary classification problem deciding if contact has occurred or not. Three conventional supervised machine learning methods are studied using experimental data captured in full-scale experiments. Logistic regression, a support vector machine and a long-term short memory network have been trained and investigated. The results are promising and a proof of concept illustrating that supervised machine learning is a viable strategy for quay contact detection using motion sensors.

Capsulolabral Adhesions After Hip Arthroscopy for the Treatment of Femoroacetabular Impingement: Strategies During Rehabilitation and Return to Sport to Reduce the Risk of Revision

AbstractThis article will review various strategies such as passive range of motion modalities, active range of motion movements, and pharmacological interventions for the prevention of adhesion formation after hip arthroscopy. Capsulolabral adhesions are a common cause of revision hip arthroscopy for which treatment methods are still evolving. Efforts to prevent and limit their formation postoperatively, including adjuncts such as losartan, as well as the use of consistent passive and active, multiplanar movements, both therapist and continuous passive motion machine assisted, should be considered.

Moto-contínuo: deslocamentos de travestis em uma perspectiva etnográfica

Abstract Intense mobility is a characteristic observed in the context of travestis who work in sex markets. Studies on the subject usually emphasize that this mobility is related to a project of refinement, social ascension, and greater social, symbolic, and economic well-being, besides serving as a project of transformation and beautification of the bodies. Based on ethnographic work, I argue that, in order to understand the various orders of displacements of travestis, it is necessary to understand such movements as a perpetual motion machine, and not as being determined by imperatives that would necessarily lead to displacements from one place to another in search of something - much less something exceptional. In the observed context, displacements are a way of being in the world. Events occur during the displacements, not because of them.

Planetary Motion Machine.

Planetary Motion Machine.

Optimization method for complex surface partitioning and cutting parameters in 5-axis machining

For complex surfaces with variable geometric features and high processing requirements, the current stage still uses more conservative machining cutting parameters to generate five-axis machining tool positions, which inevitably leads to some parts not to obtain the best cutting state, and the generated machining tool positions are poorly adapted, so it will produce a great processing deformation error seriously affects the surface quality. In addition, conservative cutting parameters applied to different geometric features of the surface area is very likely to induce dramatic changes in the machining process cutting forces and machine motion parameters, resulting in uneven distribution of machining errors and local super poor, seriously affecting the quality of machining. In five-axis machining, due to the introduction of two rotary axes, the tool vector can be rotated arbitrarily in the spatial domain. When machining complex surfaces, the distance between the tool center coordinates and the oscillation center or rotation center of the five-axis machine will change with the curvature of the surface. surface quality. Therefore, the optimization of tool cutting parameters in 5-axis simultaneous machining is a technical bottleneck that needs to be solved urgently.

Stretchable, adhesive, antifreezing and 3D printable double-network hydrogel for flexible strain sensors

As a new flexible strain sensing material, hydrogels have broad application prospects in the fields of wearable electronic devices, human health monitoring devices and robot aided devices. Therefore, multiple excellent properties of hydrogels were taken into account simultaneously in this work. Double-network (DN) strategy of combining hardness and flexibility was adopted, and the plant materials were adhibited (nanocellulose and proline). The mechanical properties of hydrogels could be significantly improved by combining nanocellulose with conductive ions (stress of 0.293 MPa and strain of 2587%). The excellent antifreezing properties (the conductivity was 0.087 S m−1 at −20 °C) and adhesiveness of hydrogels were endowed with the zwitterionic proline, which was significantly accumulated in plants under low temperature stress. The prepared multifunctional hydrogel was suitable for 3D printing, which provided a new approach for producing complex geometry. Multifunctional hydrogel could be used as a flexible strain sensor to detect human movements, including limb bending, facial expression and vocal vibration because of its outstanding strain sensing characteristics. Hence, we expect it to be an ideal candidate material to flexible electronic detection equipments for human motion detection or machine motion feedback in the future.

JUSTIFICATION OF THE CHOICE OF TECHNOLOGICAL EQUIPMENT FOR SOD PEAT EXTRACTION FOR ACTIVATED CHARCOALS PRODUCTION

The results of the use of technological equipment for the extraction of sod peat as a raw material for the production of activated charcoals are presented. It is shown that more acceptable variant, from "price–quality" point of view, is the option with the use of equipment manufactured by RUE "Mogilevenergo". The modernization of the spinneret of KTD-1 machine has been substantiated, which makes it possible to obtain activated carbon of the required quality from the extracted products. The main technical and economic indicators of its application have been determined: productivity, fuel consumption and labor costs for the extraction of 1 ton of peat of standard moisture content, utilization rates of cycle and working time. It was found that replacing of standard mouthpieces with a diameter of 75 mm by mouthpieces with a diameter of 40 mm reduces the field loading density and cycle charges. At the same time, the extraction of sod peat of a smaller diameter (within the limits of the investigated ones) increases the seasonal harvest, in our experiments – by
 1.4 times. Optimal schemes for the movement of machines on working aisles have been developed, which ensure highquality
 performance of all operations provided for by the technological regulations. The main reasons that reduce the productivity of the KTD-1 machine when extracting sod peat with a diameter of 40 mm are established, and methods for their elimination are proposed. It is shown that for the stable operation of KTD-1 mining machine, the timber content of peat deposit should not exceed 1.5 %.

ANÁLISE DINÂMICA EXPERIMENTAL DE ROTORES DESBALANCEADOS

Rotating machines in motion usually produce dynamic forces that diffuse to the ends that support them, such efforts can lead to disadvantageous reactions to the operation of the machine, as well as unbalance or misalignment that can damage the shaft-rotor assembly or the elements directly linked to it. The objective of this project is to develop a mechanical and experimental system that enables the testing and data acquisition of a rotating machine and build a computational algorithm to generate amplitude and velocity diagrams as a function of time and compare the dynamic behavior of a vibrational bench, in normal and unbalanced condition.

Development of an Automatic Tracking Camera System Integrating Image Processing and Machine Learning

This paper describes the development of a robust object tracking system that combines detection methods based on image processing and machine learning for automatic construction machine tracking cameras at unmanned construction sites. In recent years, unmanned construction technology has been developed to prevent secondary disasters from harming workers in hazardous areas. There are surveillance cameras on disaster sites that monitor the environment and movements of construction machines. By watching footage from the surveillance cameras, machine operators can control the construction machines from a safe remote site. However, to control surveillance cameras to follow the target machines, camera operators are also required to work next to machine operators. To improve efficiency, an automatic tracking camera system for construction machines is required. We propose a robust and scalable object tracking system and robust object detection algorithm, and present an accurate and robust tracking system for construction machines by integrating these two methods. Our proposed image-processing algorithm is able to continue tracking for a longer period than previous methods, and the proposed object detection method using machine learning detects machines robustly by focusing on their component parts of the target objects. Evaluations in real-world field scenarios demonstrate that our methods are more accurate and robust than existing off-the-shelf object tracking algorithms while maintaining practical real-time processing performance.

Features of the construction and justification of the main parameters of the walking movement mechanism technological machines

The peculiarities of the design and process of movement of technological machines equipped with a four-axle stepping motor with the method of determining the main parameters of such a mechanism are considered. The factors influencing the operation of the drive of such a mechanism, their impact on efficiency and the main ways to improve such a mechanism of movement are shown.

Experimental validation of a micro-CT finite element model of a human cadaveric mandible rehabilitated with short-implant-supported partial dentures

PurposeThis study aimed to address the predictive value of a micro-computed tomography (μCT)-based finite element (μFE) model of a human cadaveric edentulous posterior mandible, rehabilitated by short dental implants. Hereby, three different prosthetic/implant configurations of fixed partial dentures (“Sp”-3 splinted crowns on 3 implants, “Br” – Bridge: 3 splinted crowns on 2 implants, and “Si”- 3 single crowns) were analysed by comparing the computational predictions of the global stiffness with experimental data. MethodsExperimental displacement of the bone/implant/prosthesis system was measured under axial and oblique loads of 100 N using an optical deformation system (GOM Aramis) and the overall movement of the testing machine (Zwick Z030). Together with the measured machine force, an “Aramis” (optical markers) and “Zwick” (test machine) stiffness were calculated. FE models were created based on μCT-scans of the cadaveric mandible sample (n = 1) before and after implantation and using stl-files of the crowns. The same load tests and boundary conditions were simulated on the models and the μFE-results were compared to experimental data using linear regression analysis. ResultsThe regression line through a plot of pooled stiffness values (N/mm) for the optical displacement recording (true local displacement) and the test machine (machine compliance included) had a slope of 0.57 and a correlation coefficient R2 of 0.82. The average pooled correlation of global stiffness between the experiment and FE-analysis (FEA) showed a R2 of 0.80, but the FEA-stiffness was 7.2 times higher. The factor was highly dependent on the test configuration. Sp-configuration showed the largest stiffness followed by Br-configuration (17% difference in experiment and 21% in FEA). ConclusionsThe current study showed good qualitative agreement between the experimental and predicted global stiffness of different short implant configurations. It could be deduced that 1:1 splinting of the short implants by the crowns is most favorable for the stiffness of the implant/prosthesis system. However, in the clinical context, the absolute in silico readings must be interpreted cautiously, as the FEA showed a considerable overestimation of the values.

Analysis of the operation of active needle disks on erosive soils

The development of agricultural technologies, the mechanization of the cultivation of ordinary crops for a long time has gone differently in different ways. The working bodies of agricultural machines process various materials, the number of which is increasing. In addition, the way the same material is processed often changes when trying to improve agricultural technologies. All this forces us to create new mechanisms of agriculture that were previously known. The use of replaceable gear bodies on flat cutting cultivators helps to reduce the energy intensity the process and improve the quality of non-falling soil. To protect against it, various agricultural techniques are recommended: plowing along the entire slope, deepening the arable layer, the formation of irregularities on the surface of arable land in the form of holes, intermittent furrows. The article describes the mechanized protection of the soil of the technological process and technical means for growing crops on erosive lands on the slope. Methodology for improving agricultural machinery for working on the slope of erosive dangerous lands. Ways to increase the stability of the movement of agricultural machines on slopes to improve the quality of technological operations are justified. The operating mode of the active disk needle is described.

Research on system modeling and motion control simulation of automatic power trowel

Aiming at the problems that the existing control researches on the power trowel are limited to the analysis of the motion principle and the open-loop control of some mechanisms, taking a hydraulically-driven ride-on power trowel as the research object, the closed-loop control method of the point-to-point motion of the power trowel is studied. After analyzing the motion principle of the power trowel, based on the assumption of elastic deformation of concrete, the dynamic model of a single trowel is established, and the relationship between the driving force, driving moment and hydraulic moment, velocity, and angular velocity of the trowel is obtained. The whole machine motion equation of the power trowel is deduced, the point-to-point state feedback control algorithm of the power trowel is studied, and a simulation model is built to verify the accuracy of the system model of the power trowel and the effectiveness of the control algorithm. This research can provide reference for the control method design of other complex motions of the power trowel.

Simultaneous calibration of probe parameters and location errors of rotary axes on multi-axis CNC machines by using a sphere

On-machine measurement (OMM) systems with touch-triggered probes are efficacious in productivity improvement. Machine motion errors impose major limitations on their accuracy for any OMM systems, especially when rotary axes motions are involved. This research proposes a precise measurement method to address this problem by simultaneously identifying the probe parameters and the location errors of rotary axes, using a touch-triggered probe to sample a sphere. This method is suitable for both periodic machine checks and OMM system recalibrations. The method formulates a mathematical model based on machine kinematics to represent errors between the theoretical probed data and the actual recorded data, minimizing which can solve for necessary parameters. Two proposed probing patterns simplify the solution to the model. Experiment results demonstrate that the method is effective and accurate. Monte Carlo simulations were carried out to prove the robustness of the method.

Determining the energy efficiency of a resonance single-mass vibratory machine whose operation is based on the Sommerfeld effect

This paper reports determining the energy efficiency of a vibratory machine consisting of a viscoelastically fixed platform that can move vertically, and a vibration exciter whose operation is based on the Sommerfeld effect. The body of the vibration exciter rotates at a steady angular speed while there are the same loads in the form of a ball, a roller, or a pendulum inside it. The load, being moved relative to the body, is exposed to the forces of viscous resistance, which are internal within the system. It was established that under the steady oscillatory modes of a vibratory machine's movement, the loads are tightly pressed to each other, thereby forming a combined load. Energy is productively spent on platform oscillations and unproductively dissipated due to the movement of the combined load relative to the body. With an increase in the speed of the body rotation, the increasing internal forces of viscous resistance bring the speed of rotation of the combined load closer to the resonance speed, and the amplitude of platform oscillations increases. However, the combined load, in this case, increasingly lags behind the body, which increases unproductive energy loss and decreases the efficiency of the vibratory machine. A purely resonant motion mode of the vibratory machine produces the maximum amplitude of platform oscillations, the dynamic factor, the total power of viscous resistance forces. In this case, the efficiency reaches its minimum value. To obtain vigorous oscillations of the platform with a simultaneous increase in the efficiency of the vibratory machine, it is necessary to reduce the forces of viscous resistance in supports with a simultaneous increase in the internal forces of viscous resistance. An algorithm for calculating the basic dynamic characteristics of the vibratory machine's oscillatory motion has been built, based on solving the problem parametrically. The accepted parameter is the angular speed at which a combined load gets stuck. The effectiveness of the algorithm has been illustrated using a specific example

Continuous Passive Motion Machine for Elbow Rehabilitation

Continuous Passive Machines (CPM) facilitate patients in eliminating joint stiffness after surgery and lead to a faster and more efficient recovery. However, many previous CPM machined are mechanically complicated, expensive, and lack a user interface. This paper presents a new CPM machine for elbow flexion-extension and forearm pronation-supination. The machine is simple, low-cost, and equipped with Graphical User Interface (GUI). Its mechanism is designed so that it can be used on the left or right arms interchangeably. It is developed using aluminum, perspex, and steel rods. The electrical part of the machine consists of Arduino Uno to drive the motors and a potentiometer to measure the patients’ Range of Motion (ROM). The GUI for setting the exercise parameters and monitoring the patients’ progress has been developed using MATLAB software. The experimental results show that the machine has successfully provided the repetitive desired motions. The machine realizes elbow flexion-extension and forearm pronation-supination movements with 0ᵒ-135ᵒ and 0ᵒ-90ᵒ ranges of motion (ROM), respectively. The machine is also capable of increasing the elbow joint’s ROM by 5ᵒ increments for the therapy. The results show that the machine has the potential to be used in hospitals and rehabilitation centers.