This study aims to develop a solid bolt/nut model utilized in 3D-FE analysis for the strength design of mechanical structures with bolted joints to obtain the internal forces and the bending moment acting on the bolt/nut assembly. A solid bolt/nut model has an advantage to save the time for calculation drastically since it requires fewer numbers of elements and contact surfaces. On the other hand, the solid model has to have the same axial and flexural stiffnesses as the actual bolt/nut assembly to maintain the accuracy of the equilibrium of forces and displacement in the bolted joint and of the internal forces or stresses acting on the bolt/nut assembly calculated. This study depicts how to determine the design parameters for the solid model directly from the specifications of actual bolt/nut assemblies appropriately. To demonstrate the validity of the solid model developed, the stresses acting on the bolt/nut assembly in a cylinder cover bolted joint subjected to internal pressure are calculated by 3D-FE analysis using (a) fully modeled axi-symmetric bolt/nut assembly and (b) the solid bolt/nut model developed. The results obtained using the solid model proposed coincide accurately with the ones using the fully modeled axi-symmetric bolt/nut assembly model, and show good agreement with the measurement using the strain gauges put on the bolt shank as well. This clearly highlights the effectiveness and usefulness of the solid model developed.

The Authors proposed an electromechanical integrated harmonic piezodrive system. The stability of the output speed of the drive system has important effects on its operating performance. Here, the electromechanical coupled torque equations of the drive system are presented. The transfer function of the speed control system is derived based on the torque equations. The speed fluctuation of the harmonic piezodrive system is analyzed. With a speed feedback controller and a periodic compensated control voltage, the speed fluctuation of the drive system was removed, and the stability and response speed of the control system was improved.

Thermal design is essential when developing various types of technological devices, especially miniaturized electronic devices. Conventional thermal design methods that only focus on macrostructures can provide only limited improvements in electronic device performance. On the other hand, in recent years, the implementation of nanostructural designs that take advantage of the unique properties of heat conduction at the nanoscale has resulted in electronic devices offering unprecedentedly high performance. Nanoscale heat conduction is a ballistic process, whereas heat conduction at the macroscale is diffusive. When a system is a two-phase domain, temperature discontinuities occur on the material interfaces. High-performance devices have been developed by utilizing these unique phenomena, especially the interface effect. However, few reports have proposed thermal design criteria, and thermal designs have been dependent on heuristic approaches. The development of design guidelines applicable to nanoscale thermal problems is a fundamental requirement, and one of the most effective design criteria is shape sensitivity, which indicates how to deal with material interfaces based on physics and mathematics. In this paper, we propose a shape sensitivity analysis method for a two-phase thermal design problem considering temperature discontinuities. We first explain the difference between nanoscale and macroscale heat conduction and introduce a numerical analysis method for nanoscale heat conduction based on the Boltzmann transport equation. Next, we construct a method for shape sensitivity analysis for a heat conduction problem considering two-phase nanoscale effects such as temperature discontinuities, by expanding the work of Pantz, based on Céa’s method. The validity of our shape sensitivity analysis is demonstrated through two numerical examples.

A working pitch cone based geometry design approach for the intersected beveloid and cylindrical involute gear pair with small shaft angle was proposed. The cutter and geometry design parameters can be determined by the proposed method. Also, a quasi-static loaded mesh model was developed to calculate the contact characteristics. Then the influences of torque load, helix angle and misalignments on the mesh behaviors were investigated. Results show that the contact type is point contact both for light and heavy load situations. The increase of load tends to increase the root stress, transmission error and mesh stiffness obviously. However, the variations of the peak-peak value of transmission error and mean value of the mesh stiffness are greater under light load level compared with heavier load level. The increase of the helix angle obviously tends to increase the contact area, which is desirable. It also decreases the peak-peak value of transmission error and increases the mean mesh stiffness due to more area coming into contact. The shaft angle error tends to shift the position of the contact pattern and the peak value of the root stress along the tooth width direction slightly. Overall, the contact characteristics are not sensitive to the shaft angle error and gear axial position error.

During machining Al/SiCp composites, the machined surface takes on many defects such as grooves, pits, voids and protuberances, which greatly affect the characterization parameters of surface topography. However, a detailed investigation of the formation mechanism of surface defects in machining Al/SiCp composites is still lacking, and few surface roughness evaluation methods have been developed for separating the surface defects from roughness. In this paper, the formation mechanism of surface defects is revealed, and a roughness extraction method based on DT-CWT is established to extract the surface defects from roughness and conduct a roughness evaluation on the machined surface of Al/SiCp composites. Compared with the least-square method and Gaussian filter, the roughness extraction method based on DT-CWT has higher stability and can effectively distinguish between surface roughness and surface defects. According to the surface roughness evaluation based on the roughness extraction method, it is found that the surface roughness value of 2024Al/SiCp composite is lower compared to 6063Al/SiCp composite.

The main advantages of polymer gears compared to metal gears are low manufacturing costs for mass production, vibration damping, and there is no need for a lubricant. In the literature and guidelines, the allowable gear endurance limits for bending and contact stresses are mainly given for polyamides (PA) and polyacetals (POM). A large number of suitable polymer gear materials is available, but the standards offer little support for the lifetime calculations of polymer gears from other materials. Therefore, the testing of gear geometry and materials combinations cannot be avoided in the design of an optimal gear drive. However, gear testing is very time-consuming and expensive, especially when testing several different material combinations in different testing conditions. By applying the upgraded accelerated testing procedure, gear test time and costs can decrease significantly. Determination of the gear temperature during meshing is needed for the precise calculation of plastic gears. The presented temperature calculation model is corrected and improved with input parameters, which were determined from the test results. Accelerated tests were conducted on different combinations of reinforced and unreinforced commercially available materials: PA6, PA66, POM and PPS. Glass and carbon fiber were used for reinforcement. The research goal was characterization of different material pairs with the coefficient of friction, time strength, wear, and the failure mechanism in relation to load cycles and load level. The paper's contribution are some general guidelines for selecting polymer material for gears, such as fiber reinforcement improves the allowable stress level at up to a few million load cycles; unreinforced polymers are better for a higher number of load cycles. Also, PTFE - the internal lubricant significantly reduces a coefficient of friction if added to PA polymers, and is less efficient in combination with POM.

This study proposes an intelligent multi-objective model predictive control method in which an artificial neural network and a genetic algorithm are used to realize satisficing decision-making, which is an interactive multi-objective programming technique. We considered model predictive optimization under a dynamic environment with multiple objectives. To predict nonlinear function forms with dynamic plant characteristics, we applied a recurrent radial basis function network, which is a type of artificial neural network. For optimization with multiple objectives, we applied a satisficing trade-off method along with metaheuristic optimization in the form of genetic algorithms. The features of this control method are as follows. (1) Several conflicting control objectives can be optimized in online control based on multi-objective evaluation through human-computer interaction and (2) an optimal and flexible plant control can be performed within a restrained practical computing time for real-time applications, with acceptable control quality using online adaptive model prediction. This study demonstrates the success of model prediction using computational intelligence combined with an interactive optimization technique for multi-objective model predictive control problems by applying the proposed method to steam turbine start-up control with multiple objectives consisting of the start-up time and rotor thermal stress of the steam turbine. The dynamic simulation results showed an effective control performance within a reasonable computing time.

The underwater welding robots are replacing humans in several harsh working environments however further strategies are required to achieve better control of robotic motion in order to extend their utility. This paper presents a smooth trajectory control strategy to improve the welding quality and efficiency using an underwater welding robot to perform the arc welding process. First, a mathematical model of the underwater welding robot is established using the D-H parameter method. Second kinematics equations for the movement of the robot are deduced. To improve the accuracy of the trajectory, the tool coordinate system is calibrated using the six-point method. Finally, linear interpolation with parabolic transition is combined with a six-dimensional space vector to develop a Cartesian space trajectory planning for the robot, which can ensure a smooth welding process. The results show that by using the above control strategy for underwater welding experiments, a smooth welding seam is achieved, which improves the weld quality and shortens the time taken to complete the weld.

When three-dimensional positioning devices such as a robot arm are operated, it is desirable for the devices to be operated by humans without the need for prior practice. The operating method in which the operator moves his/her arm and the device performs the same motion is a possible method. However, a difference may exist between the intended arm motion of the operator and the actual motion. In such a case, the positioning device performs the unintended than the intended motion of the operator. Therefore, in this study, the difference between the intended arm motion of the operator and the actual motion was investigated experimentally, supposing that the operator operates the device by his/her arm motion. The experimental results revealed that the operator tends to move the wrist joint center along a curve even though he/she intends to move it linearly. As an example, if the operator intends to move the wrist position straight in the right and left directions or the up and down directions, the actual wrist position tends to move along a curved path convex to the far direction. By considering the observed difference between the intended arm motion and the actual motion, an operating method was established. This method uses conversion equations to calculate the intended arm motion of the operator from the measured data of actual arm motion. In another experiment, operations using the new conversion equations and the conventional operation method were carried out. The results were compared and the effectiveness of the proposed method was confirmed.

This article presents the mixed phase as the pressure medium of hydraulic artificial muscles, which has rarely been mentioned before. Then a novel mixed phase activated artificial muscle is designed. Through this method, the weight of artificial muscle can be reduced effectively compared with the traditional hydraulic artificial muscles. The artificial muscle shows the same advantages of the hydraulic artificial muscles, more than that, this artificial muscle has a good anti-bending and anti-extrusion capacity. Despite the actuation mechanism of the hydraulic artificial muscles, the characteristics of the mixed phase activated artificial muscles have not been widely studied. The muscle is tested of its anti-deformability under the uniform load and the concentrated load respectively. The characteristics of contraction and expansion are studied in different pressure conditions and the weight reduction of the pressure medium is analyzed. Moreover, the gravity model is established to adapt to any kind of pressure medium. At last the bending test of flexible arm which composed of three parallel artificial muscles is carried out. The bending capacity and grasping ability are analyzed. Furthermore, the experiment of the arm is conducted underwater.

An increasing number of multi-motor driving systems (MMDSs) appear in the new energy, transportation and aerospace owing to its high reliability, small weight and size, and other beneficial features. Multiple motors drive the gear assembly in these transmission systems. Uneven load distribution (torque or speed synchronization issues) and motor fault are the most likely problems in their usage. The interaction between the motor and the gear transmission system plays a major role in the synchronization and dynamic characteristics of MMDS, especially when a motor fault occurs. Therefore, the influence of a motor fault on the synchronization and dynamic characteristics of MMDS will be investigated. An electromechanical coupling dynamic model of MMDS is established by using node finite element method. The numerical calculation is used to predict the synchronization and dynamic characteristics of system, and the experiment is performed to validate the model. Results show that the speed synchronization characteristic between the non-fault motors is affected less by the motor fault; However, the motor fault has a relatively large influence on the torque synchronization characteristic and the stator current synchronization characteristic between the non-fault motors. In addition, the motor fault has an important influence on the dynamic characteristics of the system; it not only increases the dynamic responses amplitude, but also slightly changes the compositions of the excitation frequency. In the practical engineering, the stator current can be selected as the feedback signal to monitor the output torque and torque synchronization characteristic of motor.

The generation principle of composite cycloid is proposed for the tooth profile of external drive. Firstly, a two-link mechanism is developed as the equivalent mechanism to describe the geometric principle of cycloid by introducing the motion transforming method. Then the path curve of n-order cycloid motion is generalized using n+1 link mechanism. The new second-order, third-order and fourth-order composite cycloid equations of tooth profiles, including the corresponding link mechanisms, are derived and compared. It is found that the fourth-order composite cycloid is more suitable and potential for the gear design. Secondly, based on differential geometry and meshing theory, the mathematical models, including original composite cycloid profile, meshing equation, conjugate profile and meshing line are established. Subsequently, the meshing properties, such as contact ratio, sliding ratio and mechanics property analysis are conducted and compared with involute gear drive. Transmission efficiencies under different operating conditions are performed on the FZG gear test rig. Theoretical and experimental results demonstrate that greater contact ratio, smaller sliding ratio, superior bending and contact stress, and high efficiency of the new gear are represented in comparison with the involute gear.

To avoid back injuries, caregivers are advised to use transfer-aid equipment while transferring a patient from a bed to a wheelchair. Although the usage of such equipment has been recommended for several decades, it remains unpopular in several countries, including Japan. The current study investigates the feelings of caregivers regarding the usage of transfer-aid equipment, the cause of their feelings, and the measures that can be considered in order to increase the acceptance of transfer-aid equipment by the extensive caregiver community. The relations among the movements of users (caregivers and patients) and impressions of the caregivers regarding the equipment, while monitoring the usage of the equipment, were analyzed using Kansei engineering. The relations revealed six distinct feelings that are related to users’ movements while using the equipment.

The motors for industrial robots and transporting robots require high-precision positioning, large torque output, and downsizing. However, conventional motors have difficulties in downsizing or supporting large torque. In this research, we propose a novel reducer-integrated motor to solve the problems of existing motors. The proposed reducer-integrated motor has a differential gear mechanism using the simultaneous engagement of two kinds of external and internal gear pairs: one with a small difference in teeth number and the other with no difference in teeth number. Inside the reducer, linear actuators are installed. Two gear pairs with no difference in teeth number are fixed on the base and the gear pair with a small difference in teeth number is set between them. When the linear actuators revolve the external gear, the two kinds of the gear pairs engage simultaneously and the internal gear of the gear pair with a small difference in teeth number outputs the rotation. It is thought that the structure of the proposed motor can realize downsizing of the entire motor system, high load-supporting capacity, and high stiffness. In this paper, the structure and movement of the proposed motor are explained. The geometrical conditions for simultaneous engagement of the two gear pairs with small and no differences in teeth number are clarified. Through the discussion on the solution satisfying the conditions and the relation with the bending strength, a design method for the reducer of this motor is proposed. An experiment conducted on a prototype verifies that the proposed motor works as expected.

Parallel link robots are now being applied to various assembling tasks for small products and components. One of the important issues for design of the parallel link robots is to improve their kinematic motion deviations due to the complex link structures. The kinematic motion deviations of the parallel link robots are deeply influenced by the geometric deviations of the components, such as joints and links. A systematic design method is required for specifying suitable geometric tolerances of the joints and the links, in order to improve the kinematic motion deviations of the parallel link robots. The objective of the present research is to establish a computer-aided design system for specifying a suitable set of the geometric tolerances of the components considering the trade-off between the requirements on the kinematic motion deviations and the ease of the manufacturing processes. A mathematical model is formulated to represent the standard deviations of the kinematic motions of the end effectors, based on the tolerance values of the joints and the links. A systematic method is proposed here, by applying an optimization method, to determine a suitable set of the tolerance values of all the joints and the links under the constraints on the kinematic motion deviations of the end effectors. The method is applied to some design problems of the geometric tolerances of the parallel link robots.

Bending strength of injection molded polyacetal test gears is investigated in back-to-back testing using oil-lubrication. To validate state of the art calculation methods, tooth geometries with a variable number of teeth are investigated, maintaining a constant center distance and transmission ratio. To enable testing on a constant level of tooth temperature for variable torque loads and speeds, occurring tooth temperatures are measured and considered in latter testing. Test results show that bending strength of tooth geometries with a higher number of teeth stand higher tooth root stresses acc. to VDI 2736, as the calculated tooth root stress is too high due to negligence of load-induced deflections. A modified method for calculating tooth root stress considers load-induced deflections, allowing to trace back the failures of the different tooth geometries to a common stress level. Therefore, a possible approach to consider the actual contact ratio for tooth root stress calculation of steel-plastic spur gear pairings is proposed.

Recently, facilities with the special intention to help people who lack walking ability or even sit in the wheel chair could be seen everywhere. However, in the hospitals, rehabilitation devices, which are used for people to regain their body functions right after some health problems, are very limited, and even the existing robots have not shown sufficient evidence to prove they are useful, low cost, or easy to handle to be used as a regular rehabilitation method. In this research, a 3-DOF parallel mechanism training device as a compact foot drive mechanism for the gait rehabilitation of walking-disabled patients was developed for solving these sorts of problems. The requirements and constraints were obtained through interviews with medical doctor, physical therapists and related researchers. The composition of this proposed training device is: patients can be supported by a harness system with their feet fastened onto two separated programmable footplates. Based on the preprocessed walking data captured from healthy individuals, reference motion for the footplate can be determined and used to calculate the specifications of the footplate drive mechanism. As the foot drive mechanism, a planar parallel mechanism with 3-DOF was selected. Its dimensional synthesis was carried out taking into consideration the workspace and motion transmissibility, and a prototype of the machine was designed and built in the end. Comparison between the walking data and mechanism ’s analysis indicated that it is possible for the machine to generate natural walking patterns, which will be further proved with a prototype in the future.

In this work, a deterministic and probabilistic life assessment for a traditional car starter motor, with the help of timely diagnosing of the starter faults and predicting its remaining useful life, based on number of stop/start cycles, and the corresponding brush and commutator wear, is realized. Furthermore, empirical equations accounting for deterministic and stochastic conditions, which can give the remaining useful life for both the commutator and brushes, are developed by utilizing curve fitting methods for fitting the experimental data, and Monte Carlo method for stochastic calculations. Use of the stochastic one, with the aim of real-time condition monitoring of the health of the starters in a car, can make sense to obtain the most robust and reliable cycles with the consideration of the uncertainties arising from human factors and accuracies of the measurement instruments. Moreover, the proposed empirical models produce life predictions in fair enough agreement with the experienced ones when compared; thus, the brush is concluded to be one of the most likely components to fail during the life of the starter. For the adaptation of the deterministic or stochastic models to other type internal combustion engines, the modification of the proposed models for both components in such a way that it could involve less efforts; for example, few similar experiments to be implemented on the different types of the engines or the directly consideration of the required torque to which the engine is exposed, might be several reasonable solutions that accordingly could save the development time and reduce costs.

To improve positioning accuracy of a magnetic head in hard disk drives (HDDs), a triple-stage-actuator system was proposed with a thermal positioning actuator for a magnetic head positioning system. This positioning system has three types of actuators: a voice coil motor (VCM), piezoelectric (PZT) actuators, and the thermal positioning actuator. In this system, a magnetic head has a heater located in a horizontal direction of read/write elements as the thermal positioning actuator. By using this structure, the control system can move the position of read/write elements of the magnetic head in a horizontal direction with thermal expansion induced by the heater with an electric current. The thermal actuator systems have simple characteristics without mechanical resonant modes even in a high frequency range. This means that the thermal actuator is good for positioning control in high frequency range. As a result, the triple-stage-actuator system enable us to improve the positioning accuracy during a track-following control from conventional dual-stage-actuator systems. However, the thermal positioning actuator causes flying height fluctuations of the magnetic head that could lead to fall of magnetic recording performances. In HDDs, the magnetic head has another heater located in a vertical direction of read/write elements in order to control flying height of the read/write elements. This control system is called thermal flying height control system. In the previous study, we can compensate for the flying-height fluctuations by using a feedforward control scheme of the TFC system. However, the feedforward control has little robustness against the plant perturbations. To address this issue, this paper employs a two-degree-of-freedom(TDOF) control scheme for the coordinated control with the TPC and the TFC systems. By using proposed TDOF method, we can compensate for the flying-height fluctuations against the plant perturbations. Simulation results showed that the proposed method is able to improve robust performance against the plant perturbations.

The drum shearer is one of the main equipments of the long-wall mining system that has been widely used in coal mining for decades. Influenced by large fluctuation and intensive impact of drum load, the drum driving system is a weak part of the drum shearer due to the large dynamic deformation on ranging arm housing and the changes of gear meshing state. Since previous studies did not consider the coupling effects of housing and gearing transmission system, this study is concerned with hybrid finite element/lumped parameter dynamic modeling of the housing-transmission coupled system. In order to model the drum driving system, it is subdivided into two substructures: housing and transmission system. The housing is modeled by finite element method while the transmission system is modeled by lumped parameter method. The dynamic sub-structuring method (DSM) is used to develop a hybrid dynamic model, taking elastic coupling between the housing and transmission system into consideration. Then the influence of housing topological optimization on the dynamic characteristics of drum driving system is also analyzed through the hybrid dynamic model. The housing topological optimization is conducted through the Optistruct solver in Hypermesh, aiming at increasing the natural frequency of housing. It can be concluded that the ranging arm housing topological optimization could reduce the dynamic deformation of the housing and thus also reduce the equivalent mesh misalignment. However, the influence of housing topological optimization on the dynamic meshing force is not very significant.

Single-crystal infrared (IR) spectroscopy is a promising method for protein structure analysis, where a protein crystal sample is fixed in a micro flow cell. Single-crystal calcium fluoride (CaF₂) is expected as the flow cell substrate material for its excellent optical property. However, CaF₂ is a highly brittle material having strong anisotropy, thus is extremely difficult to machine. Up to date, there is no available literature on fabrication of CaF₂ flow cells. In this study, micro flow cells of single-crystal CaF₂ were fabricated by ultraprecision cutting technology. Fly cutting was conducted using a single-crystal diamond tool having straight edges to generate a depth-varying rectangle cross section for the flow cell. The effects of cutting direction, workpiece orientation, undeformed chip thickness and tool rake angle on cutting behavior were investigated. Based on experiments and analysis, optimal conditions for ductile machining of micro grooves in CaF₂ were identified. As a result, a 10 μm deep CaF₂ micro flow cell with surface roughness of 2.4 nmRa was successfully fabricated. Using the fabricated flow cell, IR spectroscopic analysis of a protein single crystal at room temperature was succeeded. This study demonstrated the effectiveness of ultraprecision cutting technology in CaF₂ micro flow cell fabrication, which contributes to the IR analysis of protein, and in turn, the advance of life science.

With the rapid development of manufacturing technology powder compaction has been a highly-developed forming technology for manufacturing net shape or near net shape parts with complex geometries and special mechanical performances. An experimental and numerical investigation was made to study the densification behaviors during powder compaction. A series of compaction tests were carried out. A numerical model using multi-particle finite element model (MPFEM) was presented for densification analysis, particles were discretized with fine elements for precise description of inter-particle interactions, and three initial packing structures (hexagonal, tetragonal, and random) were considered in the numerical model. The simulation results of the multi-particle finite element model with random packing structure were in good agreement with experimental results, and can give further insight into the particle-level densification mechanism behind the macroscopic phenomenon in physical compaction tests. Particles’ flow behavior, stress field and energy conversion, that are related to the particle rearrangement, contact interactions and local plastic deformation, were detailed analyzed with the numerical model. The effects of friction, particle size and compacting velocity on compaction densification were discussed, and response surface studies of inter-particle friction, particle size and compacting velocity were completed for compaction process optimization.

To solve the problem of difficulty in mechanical CAD assembly model retrieval and low level of the model reuse, provide effective support for module reuse in assembly model, a novel module partition method for mechanical CAD assembly model is proposed. Firstly, the correlation strength between assembled parts is analyzed and evaluated based on multi-source correlation information including assembly structure, function and flows. Then, the weighted network is constructed for expressing correlation relationships between assembled parts in the assembly model. After that, a community detection algorithm upon greedy thought is given to discover communities in weighted network, thereby realizing the modularization of mechanical CAD assembly model. Finally, two CAD assembly models are employed to verify feasibility and effectiveness of the proposed method.

A simulation of the rolling contact fatigue strength of a traction drive element was developed. This simulation accounts for both the distribution of sizes of inclusions in the element material and the influence of traction forces at the element surface. The shear strength of the matrix structure surrounding an inclusion was estimated with an equation. The purpose of this report is verifying the estimation accuracy of this simulation by comparing with the experimental result. The experiment was carried out by according to the 14 S-N testing method. The material of test rollers was carburized JIS SCM420H. The hardness distribution and the Weibull distribution of inclusion dimensions, which are necessary parameters of this simulation, were determined by observation of an actual test specimen. The calculated rolling contact fatigue strength in failure rate of 50% at 10⁷ cycles was 750 MPa with a standard deviation of 35.4 MPa. The rolling contact fatigue strength of 1120 MPa with a standard deviation of 50.8 MPa was obtained as a result of experiment. The failure mode was considered to be flaking from the internal origination. The calculated standard deviation was about equal to the experimental result. Though there was 370 MPa difference between calculated and experimental fatigue strength. Including of the hardening of roller and the influence of compressive residual stress in the simulation and the determination of the depth of failure initiation will decrease above error.

This paper describes a suitable motion system design that utilizes a thin and compact linear switched reluctance motor (LSRM) with a disposable-film mover. The motor features a simple structure that is easy to fabricate and install into existing and newly designed instruments. Made using readily available materials, the mover is considered disposable. To meet the objectives of a motion system, i.e., simplicity in terms of use and mover exchangeability, the motion performance should remain the same even when the mover is exchanged. To meet these objectives, it is desirable to provide controllers that are robust to changes to the movers, and it is important to clarify the limitations of the motion performance resulting from the different motor characteristics. Thus, using a controller designed for precise tracking, experiments were carried out to verify the robustness of the motion system against the influences of changes in the length and mass of the movers. The limitations of the motion performance were then formulated for systems with a small effective thrust force such as those used in the developed LSRM, and validated. Based on the results achieved, the range of additional mass specifically applied to maintain the same motion performance is clarified in the present paper.

In this paper, the tooth contact pattern and transmission errors of dual lead worm gears in ISO type I are analyzed using tooth contact analysis (TCA) and the worm gears are manufactured. The setting of the hobbing machine for worm wheel manufacturing and the amounts of modification in profile and lead directions of worm grinding machine for worm manufacturing are determined so that the expected meshing conditions can be obtained based on TCA results. The dual lead worm gears in ISO type I were designed and manufactured based on this method, and the actual tooth contact patterns and transmission errors were compared with analyzed ones. Compering with TCA results, actual tooth contact patters were similar to TCA results for both flanks. However, the measured transmission errors were slightly larger than TCA results. After manufacturing worm gears, the profile errors of a worm hob cutter for tool were measured using a gear measuring machine and these measured results were fed back to TCA results in order to improve the accuracy of TCA. The influence of the tooth profile errors of the hob cutter was investigated. TCA results with feedback of tooth profile errors of the hob cutter were closer to the actual transmission errors than TCA results without feedback. As a result, the validity of this method was confirmed.

Applications for remotely operated rotary wing aerial vehicles, hereafter referred to as drones, are rapidly expanding in scope and such aircraft may soon become an integral part of everyday life as well as a source of innovation. However, it is quite difficult to improve drone flight performance and reduce development costs because performance optimization depends strongly on the intended application. As a result, drones are currently developed by trial and error using various rotary wing shapes. In this study, a device for evaluating the aerodynamic performance of rotary wings is proposed. We consider it likely that our proposed device will be useful for various drone-related applications in addition to facilitating drone development because it is inexpensive to produce and can eliminate the need for large expensive laboratory equipment such as wind tunnels when performing flight characteristic evaluations. In this paper, we report on the fabrication of our 3D general fused deposition modeling (FDM) printed device along with some experimental results.

Friction stir blind riveting (FSBR) is a new joining method which eliminates the need to predrill a hole for rivet insertion. A new one-sided mechanical joining process, friction stir blind riveting (FSBR) was developed to form lap-shear joints for similar and dissimilar alloy sheets in different combinations. The similar and dissimilar joints are made from copper, Al 5052-H32, Al 6061-T6 metals. The process window was investigated of CNC machines using only three spindle speeds: 1110, 1750 and 2750 rpm. FSBR joints were observed and discussed during tensile testing. All the similar and dissimilar joints are well fabricated at 1750 rpm. Tensile testing results show that any material with copper combinations (copper used as a top plate) at 1750 rpm as riveting speed gives the appreciable ultimate tensile strength. Further study revealed micro structure of the joint interfaces, when compared with different combinations.

Since the two free parameters have significant effect on the shape of the T-Bézier curve, a natural idea arises to find the optimal values of the two free parameters for obtaining the fairest curves. In this paper, we use approximate curvature variation minimization to obtain the optimal values of the two free parameters. By minimizing an appropriate approximate function, the unique solution can be easily obtained. We outline some examples to illustrate the effectiveness of this method.

With the promoting popularization of vascular interventional surgery (VIS), the demand for the corresponding robot aided system arises spontaneously. In order to train interns, and make them faster qualified for clinical surgery, we develop and produce a master manipulator of vascular interventional surgical robot according to operational requirements in this paper. While accuracy is one of the most important indexes to evaluate a robotic auxiliary system, we have to test it before comprehensive application. The accuracy is mainly influenced by signal's transmission since the signal in the system has to go through several links which may have distortion due to reasons such as defect of mechanism, slip of wheels, etc. Thus we must carry on an experiment of testing motion signal, including displacement and rotation from doctors transmitted to the master manipulator, and analyze the results to verify master manipulator can accurately capture motion signals of doctor's hand. Above all, in order to eliminate error accumulation, we would establish error model, through which we can get an error scope at diverse displacement to furnish whole system's error compensation with this model which is of great important to improve accuracy of device and ensuing activities of project for virtual training system's design.

In this paper, we designed a hemiplegic upper limb rehabilitation training system, which allowed both single degree of freedom and composite degrees of freedom for the training of shoulder and elbow. The system contained an upper limb rehabilitation robot, a pattern recognition system and a motion control system. Firstly, we designed a novel upper limb rehabilitation robot with three degrees of freedom, with the motor and reducer innovatively placed centrally in the shoulder of the mechanical limb arm. The movement is more stable because the inertia of each joint movement is reduced. The design makes simultaneously training both the left and right arm possible. In the control system design, the movement coupling problem is solved through the inverse operation of the target action. Lastly, to further enrich information of the single feature vector, a method integrating the AR model coefficients and wavelet coefficients was proposed. A method combining the Particle Swarm Optimization Algorithm and Levenberg-Marquardt (LM) was used to optimize the BP networks, addressing the problems associated with lower convergence speed and local minimum of standard BP networks. The experiments showed that the convergence speed of the network and the recognition rate of the target action were effectively improved, which demonstrated the effectiveness of the training system.

The galvano mirror has been widely used in the field of laser processing. It has a variety of vibration modes which are due to the torsion of the motor and the elastic deformation of the mirror. To improve the mechanical structure and to identify the resonance causes, the model of the galvano mirror is constructed. Moreover, the lumped mass system model is parametrical considered to verify the relationship between each resonance frequency and the component of the galvano mirror. The galvano mirror is composed of the motor, the coupling, and the mirror. Then, the models of each part are separately constructed and finally connected to build the model of the galvano mirror. In detail, the motor model is constructed based on the torsion of the motor itself. The mirror model which is regarded as the elastic structure is constructed based on the reduced order model. The galvano mirror model includes the pitching vibration mode which is not able to be actually detected by encoder. Any parameters of the model which are able to be used for future improvements from the mechanical point of view are changed to verify the rate of change against each resonance. In addition, the coupling rigidity is changed to shift the resonances to high frequency region through various approaches and to verify the propriety of the model.

During the drilling process, many types of bottom-hole assembly are used to adjust the well inclination and azimuth. For the drilling of inclined wells or horizontal wells, it has to face problems of repeated round trips so as to control the borehole trajectory. Such problems lead to the increase in non-productive time and the drilling cost. In order to address this issue, the idea of generating different types of bottom-hole assembly without round trips of drill-string was formed. In this paper, an adjustable stabilizer has been developed to avoid repeated round trips of the drill-string. Firstly, the mechanism of adjustable stabilizer controlling the borehole trajectory is presented. Secondly, the structure and operating principle of the adjustable stabilizer are described. Thirdly, numerical verifications of the key components of the adjustable stabilizer are conducted. Finally, laboratory tests and field tests are carried out to examine the design. Results of the numerical simulations and the laboratory and field tests show that the adjustable stabilizer operates normally and three phases of the radial pistons can be reached through regulating the flow of the drilling fluid. In addition, the pressure differences for starting the phases are measured.

This paper proposes a requirement analysis approach to increase the robustness of the Kansei quality and maximise customer satisfaction for consumer electronics products. Recently, the importance of the Kansei quality such as comfort and luxury is increasing to enhance value of the product. The Kansei quality of the target product must be assessed through individual customer’s sensitivity, which will discern their preference. The customer preference has inherent uncertainties that depend on personal value. The way of reducing the influence of customer preference diversity for the Kansei quality is desired. First, to capture comprehensively the uncertainties of customer preference for Kansei quality, customer preference is evaluated by a preference evaluation test and cluster analysis. The customer preference clusters resulting from this analysis reveal the preference patterns and their frequencies. To investigate thoroughly requirements including Kansei quality for the product, the evaluation grid method is carried out for each customer preference cluster. Next, to select appropriate design factors, which strongly influence the customer preference in each cluster, multiple regression analysis for them is conducted with preference evaluation test result. Finally, by multiple-domain matrix-based expressions using multiple regression analysis, customer preference, Kansei quality, and physical design are connected with complete coverage. Using this MDM, even in complex product designs, designers can find satisfactory solutions certainly.