Linear Motion Mechanism Research Articles

Development and implementation of a novel mechanized planting method for ecological restoration of aquatic environments using degradable nutrition pots

Submerged plants play a significant role in the remediation and purification of polluted water bodies. Reconstruction of submerged plants has been considered as an important ecological method to restore aquatic ecosystems. However, large-scale and efficient plantation of submerged plants in water restoration is a huge challenge. This paper proposes a novel mechanized planting method for submerged plants utilizing nutrition pots as planting units. Firstly, the details of the mechanized planting method were introduced. The mechanized planting method involves pre-planting the reproductive bodies of submerged plants in degradable nutrition pots, and then implanting them into the underwater soil through a planting device. Secondly, the interaction force between the nutrition pot and the soil was measured. It was found that the implantation force of nutrition pots increases with planting velocity. The planting force shows a significant increase trend when the water content in the soil decreases. Thirdly, the deformation of the nutrition pot was studied through simulations. It was discovered that the deformation of the nutrition pot mainly occurs at the bottom and the side walls near the bottom, and the limited deformation ensures the integrity of the nutrition pot. Finally, a planting device with a linear motion mechanism was designed, and a typical submerged plant, Vallisneria natans was tested, using agricultural paper seedling containers as the nutrition pots. It was demonstrated that the mechanized device successfully planted submerged plant nutrition pots into the soil, and the submerged plants survived and showed a clear growth trend. The mechanized planting method of submerged plants proposed in this article is expected to provide a new and friendly technology for ecological restoration of water source.

Modeling Stiffness and Stress in Serpentine Flexures for Use in a Compliant Bone Plate

Abstract Serpentine flexures offer several advantages for use in linear motion mechanisms, including distributed compliance to reduce stress and increase range of motion. In this work, we develop an analytical model for predicting the moment, vertical deflection, and maximum stress experienced in serpentine flexures in response to an input vertical force. Two classes of serpentines are introduced and modeled with linear motion boundary conditions enforced. Finite element analysis demonstrates a mean model error of 0.86% for these metrics across many flexure topologies. Experimental testing is performed to validate the force–deflection response of three steel serpentine compliant mechanisms. The model is able to predict the experimental stiffness data with a mean error at yield of 5.3%, compared to 6.5% with finite element analysis. Large displacement simulations show the model could remain below 10% error for deflections 3–7 times beyond the mechanisms’ deflection at yield. Finally, the model’s utility is demonstrated in the design of a novel single-piece compliant fracture fixation plate that leverages serpentine flexures to deliver controlled axial motion for long bone secondary healing. Model-derived stress-equivalent flexures are compared in their transverse and torsional rigidity. The proposed model and specific findings can be leveraged to design linear motion mechanisms that incorporate serpentine flexures across a wide range of applications.

Servomotor Dataset: Modeling Health in Mechanisms with Typically Intermittent Operation

Servomotors are used in a variety of industrial applications where precise movements are of critical importance. Degradation mechanisms in servomotors have been mostly studied and modeled for systems with long duration steady state modes. However, some specialized applications require health estimation from very short duration intermittent operations, which require different analysis techniques. With such applications in mind, a simulated dataset for servomotor health modeling and prediction is described and made available for public use. The application scenario is motivated by a fine motion control rod drive (FMCRD) mechanism used for intermittent, and typically infrequent, fine motion (insertion or withdrawal) adjustment of control rods in some nuclear reactor designs. Though the drives do not run continuously, servomotor and associated linear motion mechanisms do show wear and damage during its operational lifetime. Specifically, in FMCRD such degradations may be caused by internal as well as external damage to the system. While the causes of such damage can be diverse, in simulation we model the impact of cumulative damage as an external opposing load which resists the movement of the motor shaft. Such scenarios represent effects of rod-binding and debris in the fuel channels. The dataset includes measurements such as motor currents and rotor speed which would be part of the instrumentation in a typical deployments of rotating machinery. These observable measurements can be used to predict the health state of the servomotor. Also presented are baseline results on health state estimation, formulated as classification and regression problems, which can be used by the larger PHM community for performance comparisons. This dataset is hosted at the PHM Society Data repository [https://data.phmsociety.org/servomotor_dataset/].

A novel magnetic circuit and structure for magnetic levitation ruler

The single axis linear displacement measurement system of CMM is composed of grating ruler, servo motor and linear motion mechanism. Although the measuring accuracy of grating ruler is high, the accuracy of servo motor and linear motion mechanism is low. Therefore, the complex structure limits the measurement accuracy of the linear displacement measurement system. This paper introduces a novel linear displacement measurement system named magnetic levitation ruler. According to the working principle of grating ruler and the characteristics of magnetic levitation technology, the magnetic circuit design and structural design of magnetic levitation ruler are completed in this paper. The mover core of the magnetic levitation ruler is in the stable working magnetic field provided by the stator yoke. The horizontal control coil wound on the mover core can obtain more stable ampere force to improve the control accuracy of the mover core displacement. Therefore, the mover core can be moved in step mode, and the length of each step is fixed. Each step is the minimum scale of the magnetic levitation ruler. Therefore, the mover core can implement displacement measurement while moving in a linear motion. This paper analyzes the working principle of levitation, horizontal motion, and displacement measurement of magnetic levitation ruler, and determines the structural materials and parameters of magnetic levitation ruler with the help of finite element analysis software. The simulation results show that the levitation force of the magnetic levitation ruler is proportional to the current passing through the levitation coils, and the thrust of the horizontal control coil is less disturbed by the magnetic field. Compared with the linear displacement measurement system with rotational servo motor or permanent magnet synchronous linear motor as the core, the magnetic levitation ruler has stable magnetic field, strong controllability, high integration, and is easier to achieve high-precision control.

Embedded Linear-Motion Developable Mechanisms on Cylindrical Surfaces

Abstract This study introduces methods for developing embedded straight-line and linear-motion mechanisms on right circular cylinders. Developable surfaces, particularly right circular cylinders, are the manufactured embodiment of many products. Functional linkages are traditionally not geometrically constrained to a body and often dictate the final shape of the housing they reside. This work explores mapping straight-line and linear-motion mechanisms onto cylinders for practical design. Potential applications for when an embedded cylindrical developable mechanism capable of deployment and generation of linear motion would be useful are discussed. An in vivo wiper mechanism to clean obstructed laparoscope lenses during surgery is investigated to physically demonstrate the concepts introduced in the article and to illustrate an example application.

A Method for Generating Streamwise Velocity Disturbance in Low-Speed Wind Tunnel

A method of wind tunnel testing is proposed for generating streamwise velocity disturbance in low Reynolds number flows. When a model moves along the free stream at a constant speed, the effective turbulence intensity for the translating model can be adjusted through the change in the relative velocity between the free stream and the model. The feasibility of the proposed method is experimentally verified in a wind tunnel with a linear motion mechanism installed in the test section. The experiment shows that the effective turbulence intensity for the translating model increases when the model moves along the free stream. Agreement in the lift coefficients between the tests with and without using the linear-motion mechanism confirms the feasibility of the proposed method. The experimental range available in turbulence intensity can be extended using the model streamwise translation. Moreover, a stepwise gust can be generated while the turbulence intensity remains almost constant when the model moves against the free stream.

Vacuum End Effector Equipped with an Expansion and Contraction Mechanism Using a Wound Thin Metal Plate

We propose a vacuum end effector with an expansion and contraction mechanism to realize a picking task for objects placed in a narrow space, such as a shelf. The proposed expansion and contraction mechanism consists of a tube and exoskeleton structure and is characterized by the use of a thin metal plate wound about itself to form a tubular exoskeleton. Expansion and contraction motions were realized by connecting the tube to a linear motion mechanism. The expansion and contraction mechanism can be easily extended by elastic force. In addition, the shape of the expansion and contraction mechanism is created by winding a thin metal plate around a predetermined axis, which ensures high rigidity even in the extended state. Even when an object to be picked from a shelf is located behind other objects, the end effector can efficiently hold the object because of its elongated shape and ability to freely change the position of the suction pad using a direction-changing linkage and the expansion and contraction mechanism. The developed end effector weighs about 1.46 kg and can carry a load of 0.56 kg when extended to 150 mm. Verification of the mechanism confirmed that the developed end effector is useful because it can perform the expected object-picking operation.

A Family of Novel Compliant Linear-Motion Mechanisms Based on Compliant Rolling-Contact Element Pivot

Abstract Compliant linear-motion mechanisms are of great use in precision machines due to their excellent performances such as infinite resolution and low cost. The accuracy of the mechanisms is an important consideration for mechanical design in applications, especially in the case of large working load. Considering that COmpliant Rolling-contact Element (CORE) pivot is characterized with high bearing capacity, the paper adopts it as a building block to design a family of compliant linear-motion mechanisms for applications of heavy load. These mechanisms are achieved by replacing four rigid pivots in a parallel four-bar mechanism with CORE pivots, and the motion accuracy is improved by means of contacting surfaces design of four CORE pivots. First, structures of CORE pivot are introduced and five extended arrangements for bearing heavy load are presented. Meanwhile, motion for the CORE pivot is analyzed and preconditions for achieving a pure roll are discussed. Then, configuration of the compliant linear-motion mechanisms constructed by CORE pivots is obtained, and kinematics of the mechanisms is analyzed and parametric design condition for rectilinear motion is modeled. Based on the condition, detailed topological structures of the mechanisms are designed. Finally, motion simulations and experiment tests are implemented to verify accuracy of the proposed mechanisms. The results demonstrate that the mechanisms proposed in this paper are capable of offering a high-precision linear motion and providing a promising application prospect in precision machines.

Wall Climbing Robot Based on Universal Vacuum Gripper with Bellows Linear Motion Mechanism

Wall Climbing Robot Based on Universal Vacuum Gripper with Bellows Linear Motion Mechanism

Mooring Chain Working State Detection Device

In order to change the current situation that the mooring chain magnetic particle detection is completely completed manually by workers, and improve the detection coverage accuracy, an automatic mooring chain full-ring magnetic particle detection device has been developed to fill the domestic gap. The device is mainly composed of 4 parts: a vertical scanning mechanism, a circular rotation mechanism, a probe linear motion mechanism and a probe adaptive mechanism, which have a total of 6 degrees of freedom. At the same time, ABAQUS finite element analysis software was used to check the static strength, stiffness and dynamic characteristics of the large-span vertical scanning mechanism in the device. The calculation results show that the static strength and stiffness of the vertical scanning mechanism are reliable; the driving pulsation frequency is far from the main excitation frequency, and the structure has good dynamic characteristics.

Study of Sun Position Tracking Method Based On Path of Sun Using Combine Linear And Rotary Motion Mechanism

Present paper shows the effective utilization of solar energy. Solar energy can be converted into electricity by using PV cell. The efficiency off PV Cells lowers in fixed tilt solar panel. And its efficiency depends on direction off sun rays. to recover the efficiency dual axis sun tracking system use, But disadvantage of this system is, it requires solar mapping which increases cost of system. Also this system I s very bulky, require more space and cannot transfer from one place to another. It can be used in a area where solar mapping is done. And less effective in other area. The proposed sun position tracking mechanism works faster and tracks the position of sun in less time and increases the output from solar panel.

Linear motion mechanisms in the transport of loose products in the food industry

Linear motion mechanisms in the transport of loose products in the food industry

TESTING A PROTOTYPE FRICTION DRIVE TRANSMISSION

The article presents research on the mechanical properties of a drive system using an innovative mechanism converting rotary motion to progressive motion. The operating principle of the mechanism uses the friction-based transmission of drive from the motor to the drive shaft by means of two oppositely arranged unidirectional clutches. A side effect of such a solution utilized in the mechanism is the possibility of shifting the couplings while transmitting torque. The clutches were combined with a mechanism converting rotational motion to linear motion by utilizing friction between radial ball bearings and the shaft. This has resulted in an innovative mechanism for converting rotary motion to progressive motion, with the drive source being bound with a “friction screw” (a “slide” screw). A characteristic feature of this solution is the fact that there is no need for the nut to rotate in order to achieve progressive movement. Known solutions are based on a rotating nut and a fixed shaft system. The mechanism uses a fixed pitch nut, but it is possible to use a regulated pitch nut as a possible modification of the mechanism at a later stage of the system development. The main advantage of the mechanism tested is the possibility of uncoupling, which occurs when the maximum force transmitted by the nut is exceeded. This force is related to the friction force resulting from the pressure exerted by angularly shifted ball bearings on the drive shaft. The bearings are a substitute for the screw line in the classical ball screw mechanism. The research results presented in the article give an overview of the mechanical properties of the solution developed. The article also presents the influence of rotational speed and load on the mechanical parameters of the drive. The application of the described invention as the basis of the linear motion mechanism driving the tool of a surgical robot is a safe solution with unique and desirable characteristics.

공작물 검사장치의 카메라 초점조정

In this paper, we designed a camera focus adjustment system for a workpiece inspection system. It is possible to adjust the center line of the camera vertically to the top of the horizontal illuminator and the top of the vertical illuminator, respectively, and to take the same size of object in the picture. The workpiece inspection system consisted of a body, a vertical camera focus adjustment mechanism, a horizontal camera focus adjustment mechanism, a horizontal illumination device, a vertical illumination device, and a control device. To adjust the size of the workpiece, an image of a checker board attached to the horizontal illumination device of the inspection apparatus and the vertical illumination device is acquired, calibration is performed to remove image distortion of the workpiece is measured by image processing. As a result of the characteristic test, each linear motion mechanism can be adjusted until workpiece reaches a predetermined size. Since the workpiece inspection apparatus can acquire images with a predetermined size, it is considered that the accuracy of measuring the size of the workpiece can be improved by image processing.

Design of a stiffness-adjustable compliant linear-motion mechanism

A stiffness-adjustable compliant linear-motion mechanism (CLMM) is desired in practical applications. In this paper loads are applied at the secondary stage of a paired double parallelogram (DP-DP) to adjust stiffness, based on the analysis of a combination of parallelograms. Pre-loaded parallelograms and loading springs are utilized to solve the loading problem in practical applications, and the redundant degree of freedom (DOF) is restricted to a certain extent. Meanwhile, the parasitic motion of the primary stage is diminished by arranging the configuration symmetrically. Furthermore, a model, capable of predicting stiffness characteristics, is developed through an energy approach based on the relation between applied forces and internal forces, and a Lagrange multiplier is exploited to deal with the constraints. Finally, the analytical model is verified by finite element analysis (FEA) and experiments, and the errors caused by parasitic motion are corrected for this analytical model.

Dual Langmuir-probe array for 3D plasma studies in TORPEX.

We have designed and installed a new Langmuir-probe (LP) array diagnostic to determine basic three-dimensional (3D) features of plasmas in TORPEX. The diagnostic consists of two identical LP arrays, placed on opposite sides of the apparatus, which provide comprehensive coverage of the poloidal cross section at the two different toroidal locations. Cross correlation studies of signals from the arrays provide a basic way to extract 3D information from the plasmas, as experiments show. Moreover, the remarkable signal-to-noise performance of the front-end electronics allows us to follow a different approach in which we combine information from all probes in both arrays to reconstruct elementary 3D plasma structures at each acquisition time step. Then, through data analysis, we track the structures as they evolve in time. The LP arrays include a linear-motion mechanism that can displace radially the probes located on the low field side for experiments that require fine-tuning of the probe locations, and for operational compatibility with the recently installed in-vessel toroidal conductor.

Compliant constant-force linear-motion mechanism

A fully compliant constant-force mechanism that uses an initially angled parallel-guiding mechanism is proposed. A pseudo-rigid-body model (PRBM) of the mechanism is developed and validated using both finite element models and experimental prototype testing. The PRBM is used as a preliminary design tool to identify parameters that result in a constant-force mechanism. An adjustable version of the mechanism is also proposed and is used to assess the range of validity of the PRBM and highlights how the system response can be varied by changing the flexible beams inclination. A finite element based optimization is used to create a modified version of the mechanism that incorporates beam-end rotation effects and offers greater performance. Potential applications for the mechanism are discussed and it is demonstrated as a component of a statically balanced system.

Biological Nanomotors with a Revolution, Linear, or Rotation Motion Mechanism.

The ubiquitous biological nanomotors were classified into two categories in the past: linear and rotation motors. In 2013, a third type of biomotor, revolution without rotation (http://rnanano.osu.edu/movie.html), was discovered and found to be widespread among bacteria, eukaryotic viruses, and double-stranded DNA (dsDNA) bacteriophages. This review focuses on recent findings about various aspects of motors, including chirality, stoichiometry, channel size, entropy, conformational change, and energy usage rate, in a variety of well-studied motors, including FoF1 ATPase, helicases, viral dsDNA-packaging motors, bacterial chromosome translocases, myosin, kinesin, and dynein. In particular, dsDNA translocases are used to illustrate how these features relate to the motion mechanism and how nature elegantly evolved a revolution mechanism to avoid coiling and tangling during lengthy dsDNA genome transportation in cell division. Motor chirality and channel size are two factors that distinguish rotation motors from revolution motors. Rotation motors use right-handed channels to drive the right-handed dsDNA, similar to the way a nut drives the bolt with threads in same orientation; revolution motors use left-handed motor channels to revolve the right-handed dsDNA. Rotation motors use small channels (<2 nm in diameter) for the close contact of the channel wall with single-stranded DNA (ssDNA) or the 2-nm dsDNA bolt; revolution motors use larger channels (>3 nm) with room for the bolt to revolve. Binding and hydrolysis of ATP are linked to different conformational entropy changes in the motor that lead to altered affinity for the substrate and allow work to be done, for example, helicase unwinding of DNA or translocase directional movement of DNA.

Self-stopping actuating mechanism with high coefficient of efficiency of the forward stroke for linear motion drives

In this article is examined the an approach to the design of linear motion mechanisms, which consist of self-stopping planetary transmissions of the type A H 1 3 and A H 3 1 with transmission values i = 7÷9 based on the type of self-stopping planetary transmissions and the RSM. That combination allows a reliable self-stopping in backward stroke and a high coefficient of efficiency of the forward stroke (up to 0.95). The dependences of the angles of inclination of the wheel of the self-stopping transmissions from the angle of the original profile were lead. The obtained conditions allow the transmissions work of the type A H 3 1 and A H 1 3 in release mode for the back-and-forth stroke.

Design, analysis, and testing of a motor-driven capsule robot based on a sliding clamper

SUMMARYWe propose a motor-driven capsule robot based on a sliding clamper (MCRSC), a device to explore the partially collapsed and winding intestinal tract. The MCRSC is powered by wireless power transmission based on near-field inductive coupling. It comprises a novel locomotion unit, a camera, and a three-dimensional receiving coil, all installed at both ends of the locomotion unit. The novel locomotion unit comprises a linear motion mechanism and a sliding clamper. The former adopts a pair of lead-screw and nut to obtain linear motion, whereas the latter anchors the MCRSC to a specific point of the intestinal tract by expanding its arc-shaped legs. The MCRSC is capable of two-way locomotion, which is activated by alternately executing linear motion and anchoring action. Ex vivo experiments have shown that the MCRSC is able to inspect the colon within a time frame of standard colonoscopy.