Pulley Mechanism Research Articles

Integration of the passive energy balancing based actuation system into a camber morphing design

A spiral pulley mechanism can be used to passively balance the energy between the morphing structure and actuation system. Applying the energy balancing concept has the potential to improve the performance of the actuation system by reducing the external energy consumption. In the current study, the integration workflow for the passive energy balancing device is established and is adopted in a variable camber morphing wing. The design variables of the passive energy balancing system are optimised and the effects of the different parameters are discussed together with the adaptability of the passive energy balancing device when the load stiffness changes. An integrated demonstrator was also built to validate the mechanism by measuring the currents in the process of morphing actuation.

Research on Symmetrical Flexible Clamping Conveyor for Scallion Harvester

Aiming at the problems of low conveying efficiency, poor adaptability of conveying Scallion poles of different diameters, and little innovation of the mechanism that exist in the existing clamping conveyor device, a symmetrical flexible clamping conveyor device suitable for Scallion harvesting was innovatively designed. The design and analysis of the overall structure of the clamping conveyor, the clamping mechanism, the clamping pulley and other key mechanisms were carried out, and finally the finite element simulation analysis of the clamping conveyor was carried out, and the analysis of the deformation cloud and stress cloud showed that the designed clamping conveyor could meet the requirements of the working strength. The designed symmetric flexible clamping and conveying device can automatically adjust the clamping force according to the diameter of Scallion stalks to realize efficient and lossless clamping, which is more innovative than the existing clamping and conveying devices.

An Automatic Sliding Door: Leveraging Locally Sourced Materials for Innovation

A door is an essential component of a building. It provides security and access to the different parts of a building. In the modern era, when people want everyday life to be completely automated so that work can be done easily in a short amount of time without wasting energy, automatic doors have continued to be fashionable. In addition to being effective and efficient as automation continues to develop rapidly, automatic doors are essential to curbing the transmission of infectious diseases like Ebola and COVID-19. While automatic doors are available in Nigeria, they are imported, thereby shrinking the nation’s foreign exchange. Not only that, but they also cost more when imported compared to when they are manufactured locally. In this work, therefore, a cost-effective automatic sliding door was developed using locally sourced materials from Nigeria. The door uses a passive infrared sensor (PIR) to detect a human or an object in a doorway and automatically opens and closes the door by signalling a microcontroller to activate a DC motor, which drives a belt pulley mechanism. The conceptual design of the system was designed and simulated using SolidWorks. Based on the design, calculations were made to determine the appropriate materials to source. The DC motor model was simulated using MATLAB SIMULINK as a physical model to observe how it would behave in the presence of noise, and the PID controller was tuned to give optimal performance using MATLAB Auto tuning. Some materials were locally purchased, while others were constructed through standard workshop methods. A cost-saving advantage of 95.77% and 89.13% were achieved when compared to imported equivalent types from the USA and China, respectively. The siding door was assembled and subjected to a functionality test, and it was observed that the automatic sliding door successfully detects humans and objects and actuates the motor to open and close the door after the object is out of the set sensing range of 50cm. This work is a step forward in boosting local innovation in Nigeria.

Mechanistic prediction of folding angles in 4D printed shape memory polymers under varied loading conditions

Four-dimensional printing technology empowers 3D-printed structures to change shapes upon external stimulation. However, most studies did not consider recovery under loaded conditions. This paper introduces a mechanistic prediction model for forecasting recovery angles in 4D printing utilizing shape memory polymer under various loads. The model integrates Neo–Hookean model to describe the non-linear stress–strain relationship with experimentally determined force density data to characterize polymer restoration properties under various loads. Validation was demonstrated by the recovery experiment of a 3D-printed polylactic acid-thermoplastic polyurethane composite structure loaded by means of a cord and pulley mechanism. The predictive outcomes exhibited reasonable agreement with experimental results, demonstrating a trend of more accurate forecasts as the applied load increased. The model can accommodate various active materials provided that the pertaining force density data is accessible. The predictive model supports the design, optimization and material selection for 4D-printed structures to meet specific performance requirements.

IOT-ENABLED SMART LIGHTING SYSTEM WITH INTEGRATED PULLEY MECHANISM FOR HOME AUTOMATION

Lighting systems play a fundamental role in our daily life operations. However, the typical light bulb has a finite lifespan and is often installed in hard-to-reach locations, posing a challenge when it needs replacement. To address this issue, we've developed an IoT bulb holder equipped with a pulley mechanism designed to lower itself to a user-accessible height. This innovative system also features built-in light control functionality. Our solution integrates a microcontroller with a Wi-Fi module, a mechanical motor for the pulley mechanism, and an Android app. The Android app serves as the central control hub for the system. The microcontroller manages the DC motor's position and light control, responding to instructions from the app. Light control is achieved through a relay circuit, while the pulley mechanism is operated using a DC motor with a worm gearbox. The worm gearbox was chosen for its self-locking capabilities, eliminating the need for continuous power to maintain the light bulb at the desired height. 3D modeling software was utilized to create the casing and gearing components. Tests with two different microcontrollers: NodeMCU ESP8266 and ESP32 have been conducted. A comparative analysis revealed that the ESP32 is the superior choice for IoT projects due to its enhanced Wi-Fi efficiency and connectivity capabilities.

Repair of Retracted Hamstring Tears with Hamstring Pulley Technique and Inferomedial Portal

Endoscopic repair of hamstring tears is well described in the literature, but endoscopic management for significantly retracted hamstring tears is not well described. Currently, repairing a hamstring tendon that has retracted 8 cm or more from the footprint on the ischial tuberosity is performed as an open procedure. The technique described here details endoscopic repair of retracted hamstring tears using a suture pulley mechanism and an inferomedial portal.

The Effect of Timing Between Traumatic Flexor Tendon Injury of the Hand and Surgical Intervention on Repair Failure Rates.

Flexor tendon injuries of the hand, especially in zone II, pose a challenge for hand surgeons because of the region's intricate pulley mechanism and local avascularity, and post-surgical complications such as repair failure are not uncommon. One proposed predictor of outcomes following flexor tendon repair has been timing of surgery from initial injury. However, the effect of the timing of flexor tendon repair on failure rates remains controversial and understudied. The purpose of this study was to compare the failure rates of zone II flexor tendon repairs in patients at various time intervals from onset of injury. A retrospective chart review was conducted using data from hand surgery specialists at our level 1 trauma center from January 1, 2010, through May 31, 2020. This retrospective review included 407 zone II flexor tendon repairs. The primary outcome was failure of repair. Among 407 flexor tendon repairs, there were 12 reported repair failures. The failure rate was 2.9%. In the non-failure group, the mean number of days between the date of injury and the date of surgery was 7±13 days. For the failure group, this value was 14±17 days. Repairs occurring within 14 days had a failure rate of 2.3%, while repairs occurring beyond 14 days had a failure rate of 7.7%. This study demonstrates that there is a benefit to repairing the tendon within a 14-day window, as evidenced by a lower failure rate. More research is required to determine if other complications and overall health of the hand are also improved when a repair is performed in a more expedient manner. [Orthopedics. 2024;47(2):113-117.].

Study of a three-dimensional model simulation of a speed amplified flux switching linear generator for wave energy conversion and its design optimization in the ocean environment

This paper introduces a novel design of a speed amplified flux switching linear generator for the power take-off unit of an ocean wave energy converter. The design incorporates several innovative features, including semi-closed stator iron cores, four coil phases shifting, and a fixed pulley wheel mechanism. These enhancements aim to increase the generator's output power and reduce its cogging force. The fixed pulley wheel mechanism effectively doubles the relative speed of the translator with respect to the stators.The scientific originality of this work lies in the development of a comprehensive design methodology for wave energy converters, specifically focused on optimizing the power take-off design under different ocean environments. The proposed approach combines analytical techniques, hydrodynamic boundary element analysis, 3D electromagnetic finite element modeling, and machine learning methods. By synergistically employing these methods, the authors achieve an efficient and effective power take-off design.To facilitate the optimization process, a three-dimensional electromagnetic finite element model of the flux switching linear generator is developed. This model is refined and optimized to maximize the output power while minimizing the cogging force, using a regular sinusoidal wave motion as the excitation input.The experimental results confirm that the proposed flux switching linear generator outperforms conventional permanent magnet linear generators in terms of power output performance. Furthermore, the model is used to simulate and predict the generator's power output under various ocean environments, considering the hydrodynamics of the wave energy converter.In summary, this manuscript presents a significant contribution to the field of flux switching electromagnetic linear generator based wave energy harvesters. The novel generator design and the comprehensive design methodology offer valuable insights and advancements in the development of efficient wave energy converters.

Design of a Solar Powered Car (Electrical Car), Feasibility and Sustainability in Nigeria Using Imo State Polytechnics Umuagwo Site as a Case Study

The Design of a Solar Car was carried out, and its reality, feasibility, and workability in Nigeria were visualized. The sustainability was carried out by accessing and quantifying the optimal solar radiation in Nigeria using Imo State Polytechnic Umuagwo Ohaji, Imo State site as a case study. The Solar radiation on a horizontal plan and an inclined plan was calculated and quantified and their various values were compared and it was discovered that the radiation on an inclined plan was higher. The optimal mean monthly global radiation was calculated and adopted. 
 Due to the constant dynamic nature of a car, the optimal mean monthly daily average tilt angle was calculated and adopted as 15.390. The optimal mean monthly average daily tilt angle was used in the design of the car roof, such that the solar panel mounted on it will be inclined at 15.390 to ensure the maximum hardness of the optimal solar radiation. The solar energy generated is connected to the batteries via the solar charging controller. The battery connects two 12v by 100Am batteries in series. The batteries generate electric current to the D.C motor connected to the car gear through a pulley system mechanism. The gear powers and controls the movement of the car to any location.

Application of Noncircular Pulleys to Straight-Fiber-Type Pneumatic Artificial Muscle Manipulator

This study proposes a method for improving the performance of a manipulator driven by pneumatic artificial muscles. Although the straight-fiber-type pneumatic artificial muscle (SF-PAM), a kind of pneumatic artificial muscle, is lightweight and exhibits high contractile force and contraction percentage, its contractile force decreases as contraction increases. To compensate for the decrease in the SF-PAM contractile force, we developed a noncircular pulley and integrated it into the manipulator driven by a wire pulley mechanism. Because this noncircular pulley is designed in accordance with the output characteristics of SF-PAM, the contraction force of SF-PAM can be converted into manipulator torque efficiently. In addition, the radius of the noncircular pulley is expressed as a function, which can be incorporated into a numerical model for the manipulator’s controller. Subsequently, simulation and experimentation to verify the proposed method showed that, when using the same actuator, the manipulator with a noncircular pulley can optimize both output torque and range of motion better than that with a conventional circular pulley. However, a few differences between simulation results and experimental results were observed. These differences were caused by SF-PAM stretching which was not considered in the model. This drawback can be overcome by improving the SF-PAM and the numerical model in future studies. We believe that this study will provide designers of robots that coexist with humans with a high degree of freedom.

Biomimetic Soft Underwater Robot Inspired by the Red Muscle and Tendon Structure of Fish

Underwater robots are becoming increasingly important in various fields. Fish robots are attracting attention as an alternative to the screw-type robots currently in use. We developed a compact robot with a high swimming performance by mimicking the anatomical structure of fish. In this paper, we focus on the red muscles, tendons, and vertebrae used for steady swimming of fish. A robot was fabricated by replacing the red muscle structure with shape memory alloy wires and rigid body links. In our previous work, undulation motions with various phase differences and backward quadratically increasing inter-vertebral bending angles were confirmed in the air, while the swimming performance in insulating fluid was poor. To improve the swimming performance, an improved robot was designed that mimics the muscle contractions of mackerel using a pulley mechanism, with the robot named UEC Mackerel. In swimming experiments using the improved robot, a maximum swimming speed of 25.8 mm/s (0.11 BL/s) was recorded, which is comparable to that of other soft-swimming robots. In addition, the cost of transport (COT), representing the energy consumption required for robot movement, was calculated, and a minimum COT of 0.08 was recorded, which is comparable to that of an actual fish.

"Understanding Multipurpose Sieving Machine Through Literature Review"

This article is an overview of a Multi-purpose Sieving Machine, which is a machine that is typically utilized in the manufacturing industry. Because of the improvements in technology, every task that can be performed in our world can now be done more quickly and with less effort. The goal of every industry today is to increase their production rate while maintaining high product quality and standards at a lower overall cost. We have developed a mental image of a device that is capable of performing a number of distinct tasks concurrently and without much difficulty. In this particular piece of machinery, the main shaft is driven by a motor, and the slider-crank mechanism, which is responsible for sawing, is directly attached to the motor. The table is secured with a crank that, with the assistance of a DC motor, rotates the tray to vibrate it and act as a divider. The table is held in place. A pulley mechanism is coupled to the motor's main shaft, which is the shaft that is driven by the motor. As a direct consequence of this, the Sieving Machine was conceived of and created to serve the needs of industrialists and farmers operating on a global scale. The capacity to quickly and easily separate objects according to the mesh is one of the benefits, along with a reduction in costs linked to the utilization of electricity, an improvement in production rate, and the ability to generate less space, amongst other advantages. Sieving mesh, grinding, a single slider crank mechanism, agricultural use, and other related topics are included here.

Resonant passive energy balancing for a morphing helicopter blade

The idea of morphing a helicopter blade by using compliant structures promises augmented capabilities in terms of manoeuvrability and fuel efficiency. To achieve morphing, compliant structures work by elastically deforming to achieve the desired response, and therefore actuation must work against the inherent structural stiffness in addition to external loads. Passive Energy Balancing has previously addressed this problem for quasistatic loads, by adding negative stiffness elements in parallel with the structural stiffness, so that stiffness is reduced almost to zero and lighter actuators may be used. This work extends this idea to the case of dynamic actuation, where negative stiffness is optimally used to reduce the natural frequency of a morphing blade, so that it may resonate at the desired actuation frequency. A negative stiffness mechanism in parallel with the structural stiffness can be used to tailor the natural frequency of a morphing blade system. Furthermore, the negative stiffness mechanism introduces nonlinearity that has some benefits in stabilising the resonant response amplitude compared to a linear resonance, and is also shown to be beneficial to achieve a weight efficient mechanism. A spiral pulley negative stiffness mechanism has previously addressed this problem for quasistatic loads and is extended here to achieve linear frequency tailoring and nonlinear frequency tailoring, respectively. The equivalent stiffness of the extended spring used in the rotating system has been investigated. Resonant morphing strategies exploiting dynamic tailoring have been studied showing encouraging preliminary results.

Development of new passive vibration control system in coupled structures with block and tackle

An innovative passive vibration control system employed pulley tackle mechanism (Movable Pulley Damper System: MPDS) in coupled structures is proposed in this paper. A cable can be continuously stretched several times to connect the two buildings through the pulley blocks to amplify the relative displacement and provide the high energy absorption efficiency to the damper linked at the middle of the wire. The principle and the theoretical formulation of the system are initially discussed. Also, the effectiveness of the MPDS is examined through the shaking table tests using a scaled-down building model. The experiments demonstrate the ability of the MPDS to mitigate the building response during earthquake excitations as well as the successful amplification of the damping effect. The validity of the mathematical formulation and the equivalent modeling of the MPDS using the truss elements are confirmed by comparing the analytical and the experimental results.

Mechanical Variable Magnetic Gear Transmission: Concept and Preliminary Research

This letter presents a novel concept of a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">non-contact</i> variable transmission mechanism using a coaxial magnetic gear. Conventional variable transmissions have provided a function of a robust transmission shifting; However, their inherent <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">contact</i> -transmission manners such as traditional dog clutch, pulley, and load sensitive component-based mechanisms have increased their complexity, size, and weight, which restricts miniaturization and continuous operations of the system. The proposed coaxial magnetic gear-based variable transmission provides a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">non-contact</i> transmission ratio shifting mechanism by mechanically changing magnetic harmonics between coaxial components of the magnetic gear. Therefore, it may provide various features derived from the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">non-contact</i> power transmission such as uninterrupted and seamless transmission ratio shifting, backdrivable and transparent dynamics, series elastic actuation-like properties, and inherent over-load protection with an expanded operable output range. A design, mathematical model, and simulation using a finite element method magnetics of the proposed mechanism are presented. Lastly, the transmission ratio shifting is demonstrated with a prototype to verify the feasibility of the proposed mechanism.

Development of Vibration Control Structure on Suspended Ceiling Using Pulley Mechanism

A suspended ceiling system (SCS) is one of the most fragile and non-structural elements during earthquakes. However, effective seismic protection technologies for enhancing the suspended ceiling system have not been developed other than the steel bracing system. An innovative passive vibration control system is proposed in this paper, which equipped a damper-employed pulley amplification mechanism into the indirect suspended ceiling system, named the pulley–damper ceiling system (PDCS). Theoretical formulation and the detailed information on the system were presented first. In addition, a new rotational damper composition consisting of a non-linear viscous damper was developed to follow the large wire-cable stroke. Six types of the full-scale ceiling specimens of a 15.6-square meter area with different configurations were constructed for the preliminary experiments to evaluate the seismic performance and feasibility of PDCS under simulated earthquake motions. The comparative results of the shake table test demonstrated that the application of PDCS is capable of controlling both displacement and acceleration of the ceiling panels. This study also presents the nonlinear time history analyses by modeling a wire-cable as an equivalent truss element to transmit the relative displacement of the ceiling system to the damper. The analytical model accurately simulated the dynamic behavior of PDCS.

Design, Analysis and Testing of a Hydraulic Catapult System

A hydraulic catapult system is proposed to simulate the movement of the missile in the launch tube, which mainly consists of a high-speed hydraulic cylinder, an accumulator group, a main valve, a servo valve and a cable pulley mechanism. The key technical difficulties are that how to improve the response speed of main valve of big flux and increase the catapult speed in limited stroke. An ingenious controlled valve is designed and an cable pulley mechanism is applied to the hydraulic lever. The system working principle and design method are discussed. Then a system mathematical model is established, and the characteristics of the controlled valve and ejection process are further investigated through numerical simulation. Theoretical results are finally compared with the experimental ones, and it is found that they are in agreement. Finally, PID control is applied to the hydraulic catapult system, and the experimental results show that the hydraulic catapult can accurately track the velocity commands. This paper provides a valuable reference for improving high performance hydraulic catapult system in the aerospace field.

DEVELOPMENT OF A HAND-PUSH WEEDER FOR CUTTING WEEDS

An hand-push weeder was designed, fabricated and evaluated for household use and peasant farmers in order to mechanize cutting process and minimize the higher aggressive nature of weeds contrasted with harvests poising major danger to crop production, the invasion on soils is very high particularly during the raining seasons when soil moisture is high and plant development conditions are ideal. The major components of the weeder are the weeding drum and frame made of mild steel, adjustable handle made of galvanized steel, transmission system made up of belt and pulley mechanism, two wheels both at the front and rear. The highest weeding efficiency of 93.496% and field capacity of 0.055 ha/hr were obtained based on some parameters that influence mechanized weeding (soil condition, age of weed, number of weed, and optimum speed of the weeding machine been 1800rpm). The production cost of the weeder is $185 and it is powered by a 3 hp gasoline engine.

Kinematic Calibration of Cable-Driven Parallel Robots Considering the Pulley Kinematics

Pulleys used in cable-driven parallel robots (CDPRs) introduce a time-varying geometry that adds significant complexity to the CDPR's kinematic model. The proximal point-to-point method brings significant model error and makes it difficult to achieve high accuracy for CDPRs, especially when the CDPR's scale is small. To solve this problem, this paper establishes the kinematics of CDPRs considering pulley mechanisms and further develops the error model as well as the kinematic calibration method for CDPRs. Firstly, the kinematic characteristics of the pulley mechanisms are analyzed, and the complete kinematic model of CDPRs is established. Then, the error modeling method considering pulley kinematics is established, and the error identification matrix is derived. Based on these results, the kinematic calibration method for CDPRs considering the pulley kinematics is established, including the calibration process and measurement pose selection. Finally, the proposed methods are verified via both simulations and experiments by taking the translational TBot CDPR as an example. The terminal accuracy of the TBot-600 CDPR is improved by 30% with the proposed methods considering the kinematics of pulleys.

Design and validation of robotic bionic eye with multiple flexible ropes parallel mechanism inspired by oculomotor law

Producing a stable and agile bionic eye for visual image acquisition in robotics is a challenging task. In this paper, we design a bionic eye with mirror-symmetric distribution and cross-connection of flexible ropes. This mechanism is based on oculomotor law and the physiological structure of the extraocular muscles (EOMs). Specifically, the basic structural parameters are determined by Listing’s law, and the unique connection of the flexible ropes can realize the functions of the recti and oblique muscles. Furthermore, to mimic the trochlea structure, a pulley mechanism is constructed to permit the free movement of the flexible ropes. Through simulation and physical experiments, it is demonstrated that the bionic eye mechanism can move with agility under the structural parameters. The experimental results indicate that the proposed bionic eye mechanism has a superior motion accuracy of 2.798 mm, which is 6.7% of the maximum motion distance, and the repeatable accuracy of the mechanism can up to 0.210 mm.