Linear Slide Research Articles

1A1-E07 直線および円環方向の伸縮機構を有する3軸小型マニピュレータの開発

A new manipulator with a detachable commercial forceps has developed that can act as a third arm for a surgeon situated in a sterile area near the patient. A compact locally operated detachable end-effector manipulator (LODEM) with linear and circular slide mechanism was developed and tested. This device is a spherical-coordinate manipulator and uses circular stair-like slider for yaw and pitch axes, and linear telescopic slider for insertion axis to make wide working space on abdominal wall. The mass was 250g. The shortened size was 180^*60^*60mm and the expanded size was 230^*100^*60mm. The positional accuracy was 0.2mm, 1.2mm and 0.5mm respectively. A mechanism of compact LODEM was designed that allows minimally invasive robotically assisted endoscopic surgery.

B206 Initial design and FEM analysis of a non-contact power transfer method for magnetically levitated linear slider

B206 Initial design and FEM analysis of a non-contact power transfer method for magnetically levitated linear slider

Optimal Controller and Controller Based on Differential Flatness in a Linear Guide System: A Performance Comparison of Indexes

The use of linear slide system has been augmented in recent times due to features granted to supplement electromechanical systems; new technologies have allowed the manufacture of these systems with low coefficients of friction and offer a variety of types of sliding. In this paper, we present a comparison between the performance indexes of two techniques of control applying optimal control LQR (Linear Quadratic Regulator) acronym for STIs in English and the technique of differential flatness controller. The use of linear slide bolt of potency takes into account the dynamics of the DC motor; the Euler-Lagrange formalism was used to establish the mathematical model of the slide. Cosimulation via the MATLAB/Simulink-ADAMS virtual prototype package, including realistic measurement disturbances, is used to compare the performance indexes between the LQR controller versus differential flatness controller for the position tracking of linear guide system.

Design of an electrochemical micromachining machine

Electrochemical micromachining (μECM) is a non-conventional machining process based on the phenomenon of electrolysis. μECM became an attractive area of research due to the fact that this process does not create any defective layer after machining and that there is a growing demand for better surface integrity on different micro applications including microfluidics systems, stress-free drilled holes in automotive and aerospace manufacturing with complex shapes, etc. This work presents the design of a next generation μECM machine for the automotive, aerospace, medical and metrology sectors. It has three axes of motion (X, Y, Z) and a spindle allowing the tool-electrode to rotate during machining. The linear slides for each axis use air bearings with linear DC brushless motors and 2-nm resolution encoders for ultra precise motion. The control system is based on the Power PMAC motion controller from Delta Tau. The electrolyte tank is located at the rear of the machine and allows the electrolyte to be changed quickly. This machine features two process control algorithms: fuzzy logic control and adaptive feed rate. A self-developed pulse generator has been mounted and interfaced with the machine and a wire ECM grinding device has been added. The pulse generator has the possibility to reverse the pulse polarity for on-line tool fabrication.

Calculating Stability Factor Using Linear Sliding Method is Not Suitable for all Sandy Soil Slopes

To analyze the reasonable cohesion range of slope stability factor calculated using linear sliding method, different internal friction angles (20°,30°,40°) and cohesion (≤10kPa) of 36 slopes were calculated using linear sliding method, simplified Bishop method and strength reduction finite element method. The results show that, simplified Bishop method and the strength reduction finite element method are close to the stability factors; linear sliding method when cohesion is not considered is conservative, linear sliding method when cohesion is considered is partial to risk; calculating stability factor using linear sliding method is not suitable for all sandy soil slopes, only when the cohesion values not more than 1.5 kPa, the calculation results of linear sliding method are in accordance with engineering practice.

Designing, Constructing, and Using an Inexpensive Electronic Buret

A syringe-based, electronic fluid dispenser is described. The device mechanically connects a syringe plunger to a linear slide potentiometer. As the syringe plunger moves, the electrical resistance between terminals of the potentiometer varies. Application and subsequent measurement of a DC voltage between the potentiometer pins is used to track the syringe plunger position and meter the volume dispensed. The syringe’s plunger is actuated manually by the device’s user. The dispensing device offers volumetric accuracy of better than 1% when the dispensed volumes were >10 mL. The device has been used for a traditional acid–base titration experiment and produced quantitative results indistinguishable from the conventional approach using a buret. The device is inexpensive, easy for students to understand, and simple to construct.

Moment measurements in dynamic and quasi-static spine segment testing using eccentric compression are susceptible to artifacts based on loading configuration.

The tolerance of the spine to bending moments, used for evaluation of injury prevention devices, is often determined through eccentric axial compression experiments using segments of the cadaver spine. Preliminary experiments in our laboratory demonstrated that eccentric axial compression resulted in "unexpected" (artifact) moments. The aim of this study was to evaluate the static and dynamic effects of test configuration on bending moments during eccentric axial compression typical in cadaver spine segment testing. Specific objectives were to create dynamic equilibrium equations for the loads measured inferior to the specimen, experimentally verify these equations, and compare moment responses from various test configurations using synthetic (rubber) and human cadaver specimens. The equilibrium equations were verified by performing quasi-static (5 mm/s) and dynamic experiments (0.4 m/s) on a rubber specimen and comparing calculated shear forces and bending moments to those measured using a six-axis load cell. Moment responses were compared for hinge joint, linear slider and hinge joint, and roller joint configurations tested at quasi-static and dynamic rates. Calculated shear force and bending moment curves had similar shapes to those measured. Calculated values in the first local minima differed from those measured by 3% and 15%, respectively, in the dynamic test, and these occurred within 1.5 ms of those measured. In the rubber specimen experiments, for the hinge joint (translation constrained), quasi-static and dynamic posterior eccentric compression resulted in flexion (unexpected) moments. For the slider and hinge joints and the roller joints (translation unconstrained), extension ("expected") moments were measured quasi-statically and initial flexion (unexpected) moments were measured dynamically. In the cadaver experiments with roller joints, anterior and posterior eccentricities resulted in extension moments, which were unexpected and expected, for those configurations, respectively. The unexpected moments were due to the inertia of the superior mounting structures. This study has shown that eccentric axial compression produces unexpected moments due to translation constraints at all loading rates and due to the inertia of the superior mounting structures in dynamic experiments. It may be incorrect to assume that bending moments are equal to the product of compression force and eccentricity, particularly where the test configuration involves translational constraints and where the experiments are dynamic. In order to reduce inertial moment artifacts, the mass, and moment of inertia of any loading jig structures that rotate with the specimen should be minimized. Also, the distance between these structures and the load cell should be reduced.

An Automated Intestinal Biomechanics Simulator for Expediting Robotic Capsule Endoscope Development1

An Automated Intestinal Biomechanics Simulator for Expediting Robotic Capsule Endoscope Development1

Do Vision and Audition Influence Bimanual Timing Coordination for In-Phase and Anti-Phase Patterns in a Linear Slide Task?

The purpose of the present study was to investigate the role of vision and audition in the coordination of in-phase and anti-phase movement patterns at increasing frequency of oscillation in a bimanual linear slide task. The dependent variables were mean error of relative phase and standard deviation of relative phase. Results indicated that vision and audition did not influence the accuracy and the variability in performance of the two relative phase patterns, whereas increasing frequency influenced the performance of the anti-phase pattern, but not the in-phase pattern. As a potential explanation of the current findings, it is hypothesized that the bimanual linear coordination task did not rely on vision and audition because the task was perhaps governed by proprioception. With consideration for specific motor tasks, investigating the role of vision, audition, and proprioception on the performance of coordinative movements remains an important question for continued research.

A Review of Control Algorithms for Autonomous Quadrotors

The quadrotor unmanned aerial vehicle is a great platform for control systems research as its nonlinear nature and under-actuated configuration make it ideal to synthesize and analyze control algorithms. After a brief explanation of the system, several algorithms have been analyzed including their advantages and disadvantages: PID, Linear Quadratic Regulator (LQR), Sliding mode, Backstepping, Feedback linearization, Adaptive, Robust, Optimal, L1, H-infinity, Fuzzy logic and Artificial neutral networks. The conclusion of this work is a proposal of hybrid systems to be considered as they combine advantages from more than one control philosophy.

An efficient sliding-mode current controller with reduced flickering for quadratic buck converter used as LED lamp driver

This paper presents mathematical analysis, design and simulation of a quadratic buck converter used as LED lamp driver, and the performance of the converter is compared with two different control strategies. The objective is to provide tight regulation of the LED current that can operate over a wide range of DC input voltages. The first control strategy is the non–linear Sliding–Mode (SM) current controller, and its design aspects include choice of sliding surface, deriving existing and stability conditions, control parameter selection and their analysis. This paper also throws light on Average Current–Mode (ACM) controller. The operation, modelling, designing and transfer function derivation for the inner current and outer voltage loops of the quadratic buck converter are presented. The tuning of controllers for the ACM controller is done using Bode plots, for achieving desired phase and gain margins. The simulation is done using PSIM software and the results are presented.

A novel Fourier-Eight-Sensor (F8S) method for separating straightness, yawing and rolling motion errors of a linear slide

A novel method called the Fourier-Eight-Sensor (F8S) method is proposed for the separation of the straightness, yawing and rolling motion errors as well as the profiles of a linear slide. Eight distance sensors are positioned on a vertical stage in two lines parallel to the target profiles with five sensors in the lower row and the other three in the upper row. The outputs of the sensors are fused together at different times to eliminate the dependence of motion errors. The method adopts a two-stage approach. First, the profile faced by the lower row sensors is represented by Fourier series the coefficients of which are obtained by matrix inversion. Then, another Fourier series is used to represent the difference between the two target profiles. By fusing the outputs of the three sensors in the upper row and their corresponding counterparts in the lower row, the coefficients of the Fourier series are determined by the Fourier series based error separation technique. In this way, different error components can be successfully separated from the sensor outputs. The effectiveness of the method is validated by simulation and experiment.

Preform and Die Designs for Hot Forging Process of Linear Slide Block

In this study, the preform and die designs of hot forging process were proposed for a long-flat slide block. This block is assembled to the linear slide for carrying the moving table. Three different billet geometry designs were proposed to obtain good die filling. The volume of the flash is limited to 30% with a flash thickness design in 3 mm. The forging die was designed with four ejectors to push up the forged part smoothly. The proposed billet geometries and die design were evaluated using CAE simulation. The simulation results indicated that the suitable perform design is able to achieve better material flow. The flash flow control is able to reduce the forming load and improve the die filling. The forging experiments were carried out to verify the proposed method, the experiment results showed good agreement with the CAE simulations. For the Improvement of wear and corrosion resistances of Inconel718 (In718) surface, high velocity oxygen fuel (HVOF) thermal spray coating of micron-sized WC-Cr-C-Ni powder was coated onto Inconel718 surface and laser heat-treatment of the coating was carried out. Porous coating of porosity 2.2±0.4% was prepared by HVOF coating, and it was improved by laser heat-treatment, reducing the porosity to 0.35±0.08%. Micro-hardness of laser heat-treated coating increased more than four times compared to the surface of In718. Friction coefficient decreased by HVOF coating and laser heat-treatment. Wear resistance improved, decreasing the wear depth by the coating and laser heating. The interface between coating and In718 was compacted, and elements diffused from both coating and inconel718 substrate to interface, forming metal rich buffer zone (interface) and enhancing the adhesion of coating. Corrosion resistance improved by coating in sea water 3.5% NaCl solution and in 1M HCl acid, but it worsened in 1M NaOH base. For the improvement of wear and corrosion resistances of Inconel718, HVOF WC-metal power coating and laser heat-treatment are recommended.

Engineering and performance of a contactless linear slider based on superconducting magnetic levitation for precision positioning

In this paper, a contactless linear slider for precision positioning able to operate in cryogenic environments is presented. The device, based on superconducting magnetic levitation, does not present contact between the slider (composed of a permanent magnet) and the guideline (made of high-temperature superconducting disks) of the mechanism, thereby avoiding any tribological problems. Moreover, the slider is self-stable and the superconductors provide inherent guidance to the permanent magnet in the sliding DoF due to the high translational symmetry of the magnetic field that leads to low power consumption. A sub-micrometre resolution and a symmetric stroke over ±9mm have been demonstrated at cryogenic temperatures. In addition, a set of design rules for this kind of mechanism has been proposed and experimentally validated. These rules demonstrate that the performance of the device can be tuned just by modifying some geometrical parameters of the mechanism. In this way, the sensitivity and stiffness, resolution, angular run outs and power consumption can be adjusted for different applications and requirements.

A Novel Method for On-Machine Determination of Slide Motion Errors Considering Thermal Effects

This paper proposes a novel method to on-machine determine the three error components of a precision linear slide: the straightness motion, the yaw and the roll under the effect of thermal distortion caused by friction and drive. The Integrated Sensing System (ISS) is then introduced for implementing this novel method on an illustrative model of a linear slide. The error separation algorithm used in the system is based on the Fourier Eight Sensor (F8S) method. The theory and procedures are presented, and computer results are analyzed. The effectiveness of the novel method is validated through computer simulations.

Profile Estimation of Linear Slide in the Presence of Straightness, Yawing and Rolling Motion Errors

This paper presents a novel measurement system for the on-machine estimation of the profiles of a linear slide in the presence of three motion errors, i.e. straightness, yawing and rolling. The system consists of eight displacement sensors, a mounting stage and a data acquisition system. The Fourier Eight Sensor (F8S) method is employed for the error separation with software programs written in MATLAB codes. A prototype is designed, built and fitted to an axis of the precision slide. Experiments are performed to test the repeatability of the profile results under three different slide speeds. Results confirm that the proposed measurement system is capable of determining the profiles with good repeatability in the presence of straightness, yaw and roll errors of the slide.

Advanced Needle Coatings for Improved Lumbar Drain Procedure

Advanced Needle Coatings for Improved Lumbar Drain Procedure

Ultraviolet laser writing system based on polar scanning strategy to produce subwavelength metal gratings for surface plasmon resonance

We demonstrate the use of ultraviolet (UV) laser lithography in the production of subwavelength metal gratings. A laser writing system with a 413-nm Kr laser is used to write patterns on a resist-coated fused silica substrate mounted on a rotating table with a linear slider. One- and two-dimensional patterns are written in the resist at a selected sampling pitch or grating period, and the substrate is dry etched and coated with Au to obtain metallized gratings. Surface plasmon resonance dips, which appear in the reflectance spectra of the gratings, shift depending on the orientation of the incident polarization, because the gratings lack perfect symmetry owing to a system-induced skew in the writing beam. This dip shift can be considered tolerable when the gratings are used as a signal enhancer in Raman sensing applications. We conclude that UV laser writing based on polar coordinates is a candidate method for surface structuring on submicron scales. Devising a method to attain an unskewed beam will be the subject of future work.

Development of an automatic cumulative-lead error measurement system for ballscrew nuts

Ballscrew is a precision mechanical component used to convert rotational motion to linear motion in the precision linear stage. The precision measuring system for the screw's cumulative-lead error is already well known. Up to now, however, there is no suitable measuring equipment for internal cumulative-lead error of the nut. For a matching pair, it is not reasonable to understand the quality of only one piece. This paper presents a developed automatic cumulative-lead error measuring system for ballscrew nuts. The nut is clamped by a rotational stage, in which the moving angle is detected by a rotary encoder. The probing ball is inserted into the nut and remains in contact with the thread groove of the nut. The probe arm is mounted on a linear slide so that when rotating the nut, the probing ball will be pushed by the groove wall and moved axially. A high-resolution diffraction scale is employed to detect the linear movement of the probe to nanometer resolution. Combining the angular and linear motions, the cumulative-lead error of the nut can be realized. In practice, however, the nut will cause typical spindle errors during rotating, including axial slip, radial run out, and tilt motions. These errors have to be compensated in order to guarantee the accuracy of measurement results. A multi-sensor error compensation system is thus developed. Experimental results show the applicability of this developed measuring system.

A Bespoke Contact Angle Measurement Software and Experimental Setup for Determination of Surface Tension

Contact angle measurement has wide application in studying the wettability of a surface. This paper presents a contact angle measurement system developed using simple apparatus. The system consists of a bespoke measurement software, USB microscope, motorized linear position slider and a sample holder with back lighting system. The advantages of this system include user friendly, compact size, allow manual and automatic measurements and cost effective. This system is established with the contact angle and surface tension measurement experiment which is based on Fox-Zisman theory. Different probe liquids were suggested and the critical surface tension of polydimethylsiloxane (PDMS) and polyimide were determined using both the software and the hardware system developed.