Ball Screw Mechanism Research Articles

Model-free robust motion control for biological optical microscopy using time-delay estimation with an adaptive RBFNN compensator

The field of large numerical aperture microscopy has witnessed significant advancements in spatial and temporal resolution, as well as improvements in optical microscope imaging quality. However, these advancements have concurrently raised the demand for enhanced precision, extended range, and increased load-bearing capacity in objective motion carrier (OMC). To address this challenge, this study introduces an innovative OMC that employs a ball screw mechanism as its primary driving component. Furthermore, a robust nonlinear motion control strategy has been developed, which integrates fast nonsingular terminal sliding mode, experimental estimation techniques, and adaptive radial basis neural network, to mitigate the impact of nonlinear friction within the ball screw mechanism on motion precision. The stability of the closed-loop control system has been rigorously demonstrated through Lyapunov theory. Compared with other enhanced sliding mode control strategies, the maximum error and root mean square error of this controller are improved by 33% and 34% respectively. The implementation of the novel OMC has enabled the establishment of a high-resolution bio-optical microscope, which has proven its effectiveness in the microscopic imaging of retinal organoids.

Nonlinear Energy Transfer of a Spar-Floater System Using the Inerter Pendulum Vibration Absorber

Abstract The inerter pendulum vibration absorber (IPVA) is integrated between a spar and an annulus floater using a ball-screw mechanism to study its wave energy conversion potential. Hydrodynamic stiffness, added mass, and radiation damping effects on the spar-floater system are characterized using the boundary element method. It is found that a 1:2 internal resonance via a period-doubling bifurcation in the system is responsible for nonlinear energy transfer between the spar-floater system and the pendulum vibration absorber. This nonlinear energy transfer occurs when the primary harmonic solution of the system becomes unstable due to the 1:2 internal resonance phenomenon. The focus of this paper is to analyze this 1:2 internal resonance phenomenon near the first natural frequency of the system. The IPVA system when integrated with the spar-floater system is shown to outperform a linear coupling between the spar and the floater both in terms of the response amplitude operator (RAO) of the spar and one measure of the energy conversion potential of the system. Finally, experiments are performed on the IPVA system integrated with single-degree-of-freedom system (without any hydrodynamic effects) to observe the 1:2 internal resonance phenomenon and the nonlinear energy transfer between the primary mass and the pendulum vibration absorber. It is shown experimentally that the IPVA system outperforms a linear benchmark in terms of vibration suppression due to the energy transfer phenomenon.

Motorised System for Loading and Unloading of Press Dies in Press Machine

Abstract: The paper describes the use of a plate heat exchanger in transferring heat between two fluids. It explains that the design of a plate heat exchanger involves multiple heat transfer plates held together by a fixed plate and a loose pressure plate. These plates have a gasket arrangement that creates separate channel systems for the primary and secondary media, allowing for counter-current flow and effective heat transfer. To manufacture the corrugated plates, the text mentions the use of Hydraulic Press Machines with different capacities depending on the plate dimensions. The process involves changing heavy press dies, which is time-consuming and decreases overall plant efficiency. To address this issue, a proposed solution is to semiautomate the loading and unloading of press dies. A mechanical system is designed, comprising a table with rollers and linear motion guideways. The system utilizes a Ball screw mechanism powered by a servo motor and driven by a Worm Gearbox. The orientation of the motor, perpendicular to the line of motion, saves space and provides more working space on the workshop floor. In summary, the proposed solution aims to increase efficiency and safety by implementing a mechanical system for loading and unloading press dies in plate heat exchanger manufacturing, incorporating a Ball screw mechanism, servo motor, and Worm Gearbox.

AUTOMATIC COIL WINDING MACHINE

The article deals with the design of a fully automated coil winding machine for stator winding of a motor used in submersible pumps. The conventional coil winding machine winds copper wire onto a former (winding fixture). The former is attached to the sliding arm which is actuated manually. However this machine usually has material tension limitations, operator intervention and low productivity and as motors are the basic need for all operation requiring automation, the stator winding becomes the growing and essential process in automation solutions. The machine winds the coil within the slots of the former. The length of the former is 9.2 cm. The number of slots and windings per slot are customized. The winding is done by suitable methodology using various components. The three phase geared induction motor actuates the rotation of sliding arm with suitable belt and pulley arrangement. Proximity sensor is used to count the number of turns of the sliding arm. The machine winds the coil of 110 turns per minute at 120 rpm. Shifter assembly consists of series of nylon pulleys to maintain tension and linear alignment. The ball screw mechanism is used for precise slot shifting, and it is driven by stepper motor. The machine is controlled by the PIC16F877A microcontroller. The required number of turns and slots is given as input through a keypad which is displayed in a LCD. After the process is over, it is notified through a buzzer. The approximate cost of the developed machine is reduced very much.

Design and Implementation of an Active Vibration Control Algorithm Using Servo Actuator Control Installed in Series with a Spring-Damper

The membrane-type air spring can be used to suppress lateral vibration of a vibration isolation table. However, compared to voice coil actuators, pneumatic actuators are difficult to use for precise vibration control, because servo valves have nonlinear dynamic characteristics. Therefore, actuators, such as voice coil actuators, can be placed in parallel with air springs, allowing force-type actuators to provide additional force to the system. These actuators generate force. In the case of a ball-screw mechanism device or a linear servomotor, it is an actuator that generates displacement. These actuators are represented as serial active systems. Serial active systems are structurally simpler than parallel active systems. However, there are very few studies on vibration isolation systems using serial active systems compared to parallel active systems. As the two are different types of systems, a new control algorithm suitable for the serial active system is needed. This study proposes a system in which an actuator capable of accurately controlling displacement is connected in series with a support spring-damper. A new active vibration control algorithm for the proposed control system is also developed, which is termed the position input and position output. The proposed control algorithm uses the displacement of the system as an input and outputs the desired displacement of the actuator installed in series with the damper and spring. The proposed control algorithm increases the damping at the target frequency and reduces the response of the system. Numerical studies and experiments were conducted on the single-degree-of-freedom and multi-degree-of-freedom systems. The results show the efficacy of the proposed control system and the novel control algorithm for the vibration suppression of the lateral vibration of a vibration isolation table.

Analysis of the contact angle of ball screw with Gothic profile considering raceway profile manufacturing error and radial clearance

The ball screw is a mechanical linear actuator that translates rotational motion to linear motion with little friction. The elastic contact angle is considered as the key parameter for the ball screw mechanism with Gothic profile, and it is hard to measure this parameter directly. This paper investigates a calculation method for elastic contact angle of the ball screw considering the raceway profile manufacturing error and radial clearance. The method is based on two deformation model of balls under two preload states in ball screw. The deduced formula from the model on free contact angle is found to be identical with results of split inner-ring ball bearing. The effect of the radial clearance and raceway profile manufacturing error are investigated in this paper. The results show that the radial clearance is a key factor affecting the elastic contact angle. The research provides a theoretical basis for error analysis and optimization design of the new type double-nut ball screw mechanism.

Dynamic grease lubrication and friction behavior of ball screw mechanism in high-frequency reciprocating motion

Three velocities coexist in ball-groove interface, including spin, rolling and sliding velocity. These velocities change dramatically under high-frequency reciprocating motion, making the analysis of dynamic grease lubrication and friction of the rubbing surfaces extremely complicated. In present study, a transient mixed lubrication model for grease-lubricated ball screw mechanism (BSM) is developed considering the pseudoplastic flow of grease, complicated motion and dynamic load. The dynamic film thickness variation and friction characteristics are revealed in a reciprocating movement. The comparison of lubrication characteristics between ball-screw and ball-nut interface is discussed. The variation tendency of the film thickness is similar to that of the screw speed, while the evolution of the friction torque at ball-screw interface is dependent on the ball spin speed. Compared to the ball-nut interface, the friction coefficient is higher on the ball-screw interface. Besides, when the screw speed frequency and amplitude increase, the grease film thickness rises and friction coefficient decline during the stop time period. This study can provide a reference to evaluate the grease film and friction in ball screw mechanism design and optimization.

Structural dynamic vibration absorber using a tuned inerter eddy current damper

The advantages of eddy current dampers over conventional fluid dampers include the ability to produce resistive forces with no contact between the components wherein damping forces are generated, resulting in a less degradable mechanism. Thus far, the apparent mass effect, referred to as inertance, in an eddy current damper employing rotational motion has not been intentionally applied for vibration control. Therefore, this paper proposes utilizing the inertance effect in an inerter eddy current damper (IECD) to construct a dynamic vibration absorber for the seismic protection of civil structures, termed as the tuned inerter eddy current damper (TIECD). The IECD consists of a ball screw, a conductor, permanent magnets, and a back iron. The gravitational mass of the back iron disk is converted into inertance via the ball-screw mechanism, which amplifies the mass and damping effects of the rotational disk and eddy current, respectively, by converting low-speed translational motion into high-speed rotational motion. An analytical method based on the separation of variables is applied to estimate the eddy current damping force of the IECD at different velocities. Concurrently, a succinct damping model is developed to capture the mechanical behavior of the nonlinear eddy current damping. A series of dynamic tests using a small-scale prototype IECD is then conducted to confirm the feasibility and accuracy of the proposed numerical damping model. Next, an equivalent damping coefficient for eddy current damping is derived under harmonic excitation. Based on a combination of the fixed-point method, the equivalent damping coefficient of the IECD, and complex eigen analysis, an optimal design method for the TIECD is developed. Finally, the effectiveness of the proposed TIECD is validated through a shake table test and a numerical simulation.

Multifunctional water tower

The aim of this article is to present a new technical solution of the multifunctional water tower. The principle of the new designed a water tower is fundamentally based on self-sufficiency and independence of energy sources, either the energy of the sun or the wind is used. To the conversion of this energy into mechanical energy for pumping of water to storage tank is used a ball screw mechanism, which driving a high discharge displacement pump based on the piston principle.

Instantaneous Reaction and Vibration Suppression Using Two-Degree-of-Freedom Admittance Control with H∞ Feedback Controller in Surgical Training Simulator with Chiseling Operation

Surgical training simulators with virtual reality have been developed to enable surgeons to efficiently acquire and improve their surgical skills. In hard tissue surgery, the surgeon uses a chisel and mallet to cut a bone or tooth with large and instantaneous forces. In the previous study by present authors, to represent the force sensation of the cutting operation in the virtual training simulator, we constructed the force display device using the ball-screw mechanism to obtain high stiffness and display the large force. Additionally, we applied the two-degrees-of-freedom (2DOF) admittance control to react instantaneously to the impact force by pounding with the mallet. The feedback controller of the 2DOF admittance control is required to increase the high-frequency gain for improving the responsiveness of the force display device. However, the vibrational mode of the force display device can be excited by increasing the controller gain. Therefore, this study develops the design approach of the feedback controller using the H∞ control in the 2DOF admittance control system, which can be systematically constructed to reduce the vibrational mode and react instantaneously in the force display device. The efficacy of the proposed force display control system is verified through the virtual experience of the free movement and the hard contact operations.

A Novel Electronic Wedge Brake Based on Active Disturbance Rejection Control

The electronic wedge brake system (EWB) used in the automotive industry is a new structure designed for brake-by-wire systems. This paper proposes a novel EWB system which is mainly composed of a screw-driven wedged inner brake pad, a fixed outer brake pad, a fixed caliper-flexible brake rotor and a hybrid stepper motor. The proposed EWB system does not have a planetary gear set or a ball screw mechanism, it simplified the existing EWB systems. The proposed EWB system is designed to take advantage of the self-interlocking ability of the screw mechanism to hold the brakes with zero-overhauling and the self-energizing ability of the wedge brake pad to reduce the braking effort. In the braking phase, the screw driven wedge inner brake pad forces the flexible rotor against a fixed flat brake pad. The rotor is elastically deformed to make the contact against the fixed pad. Except for the applied force, the friction force between the brake rotor and the wedge pad exerts additional force as the wedge is pulled along the direction of rotation, thus requiring a lower brake actuation force. In this paper, the active disturbance rejection control (ADRC) algorithm is introduced to improve the response ability and stability of the proposed EWB. Simulations are performed to demonstrate the effectiveness of the ADRC controller in the proposed EWB system.

Development of fast photoacoustic and ultrasound imaging system based on slider-crank scanner for small animals and humans study

Integrated photoacoustic and ultrasound (PAUS) imaging is a potential imaging method that provides simultaneous in vivo functional, and anatomical information. Several PAUS scanner systems have already been reported, but they are limited to fixed scanning range, low scanning speed, bulky size, unsustainable for long-term use. Here, we report a low-cost fast dual photoacoustic and ultrasound imaging system (F-PAUSM) based on custom-made slider-crank and ball-screw mechanisms. This custom-slider-crank mechanism is versatile in terms of changing the scanning range corresponding to a suitable B-scan frame rate for difference scanning areas. F-PAUSM allows us to stably capture wide scanning ranges of 10, 18, and 26 mm corresponding to maximum B-scan frame rates of 30, 26, and 18 Hz, respectively. To demonstrate the capability of the F-PAUSM system, a dragonfly wing, nude mouse ear, and human fingertip are imaged successfully. Furthermore, the numerical analysis is conducted to estimate the fatigue life of the custom-made mechanical parts, then demonstrate that the F-PAUSM system can operate stably for long time in nominal operating conditions. These results demonstrate the potential applications of the F-PAUSM system in biomedical imaging.

Discussion on Ball Screw Slide–Roll Ratio and Entrainment Velocity Calculation

The slide–roll ratio and entrainment velocity are critical parameters in ball screw mechanism tribology investigations and are often determined by Chin-Chung Wei’s approach. Their findings indicated that substantial sliding always occurs between the ball and the raceways, which appears to violate the ball drive principle. We validated Wei’s approach using the Harris method, which is widely used in rolling bearing research. When the helix angle is set to zero, significant differences occur: when the Harris method is utilized, the entrainment velocity at the inner contact points is essentially equal to that at the outer contact points, and the slide–roll ratio is zero for both; however, when Wei’s method is utilized, the entrainment velocity at the inner side is nearly three-times that of the outer side, and the slide–roll ratio at the outer side approaches two—the level of pure sliding—which is clearly incorrect. To overcome this issue, we present an accurate approach for obtaining the slide–roll ratio and entrainment velocity for ball screws by regarding the Frenet frame as a virtual cage, which is particularly applicable to those with a long lead and operating at high speeds. Moreover, we investigated the effect of structural factors on the slide–roll ratio and entrainment velocity utilizing this model.

Practical high-precision motion control system based on nominal characteristic trajectory following control and simple feedforward element design methods

A practical design for a high-precision motion control system was formulated without an accurate dynamic model. The designed control system consisted of a nominal characteristic trajectory following (NCTF) control system—which can be easily designed without an accurate mechanical model—and time-invariant feedforward (FF) elements determined using a learning controller (LC). Specifically, an improved FF element design method, in which the LC was used to procedurally determine all the FF elements from the results of only four experiments, was used to enhance the motion control performance of the NCTF control system. To verify the effectiveness of the proposed framework, the NCTF control system was designed for a ball screw mechanism. This system was combined with the time-invariant FF element that is designed using the improved FF element design method. The performance of this system was compared with those of the conventional NCTF control system and the NCTF control system with the LC used as the FF element. The effectiveness of the improved FF element design method and combination of the determined FF elements and NCTF control system was experimentally demonstrated. Moreover, the enhancement in the position resolution of the FF element, which could compensate for the position-dependent factor in motion control, was verified. The average maximum error of this control system for the sinusoidal input with an amplitude of 0.2 mm and a frequency of 1 Hz is 0.209 μm, which is less than half the error of the other control systems.

Spall Fault Quantification Method for Flight Control Electromechanical Actuator

Flight control electro-mechanical actuators (EMAs) are among the primary onboard systems that significantly influence the reliability and safety of unmanned aerial vehicles. Recent reliability studies have shown that the ball-screw element of a flight control EMA is subject to oscillating operating conditions that may initiate rapid degradation, such as fatigue spall defects. Accordingly, detecting and quantifying such faults are crucial for developing efficient fault prognostic and remaining useful life estimation capabilities. In this study, a vibration-based fault quantification method is developed to quantify the fatigue faults of a ball-screw mechanism of an EMA. The method is based on identifying the ball passing instants through a localized surface defect on the vibrational jerk rather than the vibrational acceleration measurement. The jerk is numerically determined from conventional accelerometers using a Savitzky–Golay differentiator. This method was successfully tested for ball bearings and it is adjusted in this paper for ball-screw faults. The experimental validation is investigated on a set of fault-seeded samples on NASA’s Ames Research Center Flyable Electro-Mechanical Actuator test stand.

Experiment research of the mechatronic inerter based on active control

Mechatronic damper, that is an electromagnetic damper, has a damping force in general. The damper complies with ball screw mechanism and generator. The damping force is depended on terminal resistance of the generator, and it is controllable. However, Dr. Zhu’s group researched about the mechatronic damper based on active control, it was called mechatronic inerter, which could get an inertia force by using a force feedback PID active control, and reported in simulation. In this paper, to confirm it and moreover get switchable inertia effect, vibration tests are carried out by using the mechatronic damper and another simple control method. Finally, it is clear from the experiments that inertia effect can be varied when current goes to the generator will be controlled.

Control Method of Robot Finger Based on Ball Screw Mechanism

Control Method of Robot Finger Based on Ball Screw Mechanism

Design and development of a ball-screw and electrical motor driven industrial electromechanical cylinder

This paper presents a study on the implementation of converting an industrial pneumatic cylinder into an electromechanical cylinder drivetrain using a ball-screw mechanism and stepper motor (ECDLSM). Due to the fact that pneumatic cylinders in the industry are generally used in on-off operating mode, electric actuators provide more precise motion control (position, speed, acceleration, and force) along with providing superior accuracy and repeatability. The mechanical and electrical efficiency, force, and position errors of the ECDLSM have been examined based on the position, velocity, and acceleration profiles to the cylinder mechanism with the established test setup which consists of a current and force sensor, incremental and linear encoders, and springs. The highest ratio of the force applied-double spring was performed to verify the accuracy of the analysis results by interpreting the force data and position errors collected from the ECDLSM. The analysis results show that the ECDLSM is very useful and flexible as much as its counterparts.

Optimizing imperfect preventive maintenance in multi-component repairable systems under [formula omitted]-dependent competing risks

Existing maintenance optimization models for single-component repairable systems are extensively studied. However, maintenance optimization in multicomponent reparable systems (MCRS) is still a challenging problem, especially when dealing with stochastic dependent (s-dependent) competing risks between components. This paper develops a novel reliability-centered maintenance optimization model for MCRS operating under s-dependent competing risks. The s-dependency is captured by the joint reliability function constructed using Copula method and unknown parameters are estimated by maximum likelihood estimations (MLE). Maintenance strategies are carried out both at components and system levels. At components level, a preventive maintenance (PM) is performed whenever the reliability of the MCRS reaches a given threshold. PM actions are imperfect and modeled using the hybrid hazard rate approach. At system level, the whole system is preventively replaced after a certain number of PM cycles. The objective of the proposed maintenance strategies is to determine the optimal reliability threshold together with the optimal number of PM cycles that minimize the total expected maintenance cost rate in the infinite time horizon. The optimality conditions of the resulting maintenance optimization problem are formally discussed via two propositions. A case study that investigates a ball screw mechanism with multiple components is provided to validate the proposed approaches.

Investigation of the transmission accuracy of ball screw considering errors and preloading level

Transmission accuracy is one of the most important parameters in ball screw mechanism (BSM); however, very few researches can be found on the transmission error modeling for BSM. Therefore, on the basis of the converting principle of the errors in the normal and axial direction proposed in this paper, this paper proposes a new model to predicate the transmission accuracy of BSM considering the manufacturing errors, installation errors, as well as the transmission error due to different loading status. After the error analysis and calibration of a transmission accuracy measuring system, the transmission accuracy measurement of a typical BSM under five different preloading levels is performed. The experimental results show that the difference compared with the analytical solution is 21.6% under no preload condition, and is less than 11% under preload condition, largely owing to the uneven distribution of clearance can increase the travel deviation. Further analysis shows that the eccentricity error is the dominant factor leading to the periodic fluctuation of the transmission error. More importantly, the travel deviation increases with increasing preload, which indicates the transmission accuracy of the BSM deteriorates when the load increases.