Search

According to the analysis of a flexible tooling platform, this paper realized the overall design of the control system for the flexible tooling platform, introduced the compound of the control system and operation principle in detail, realized the design of PC control software based on Visual C++ and CATIA secondary development technology, completed the design of the servo system and the RS-485 control system network and set up a completed flexible tooling platform control system.

This article proposes the multi-axis inversionbased (MAIIC) approach. System inverse provides a nature avenue to utilize the priori knowledge of system dynamics in iterative learning control, resulting in rapid convergence as well as exact tracking (for nonminimum-phase systems). The benefits of system inverse, however, are not fully exploited in time-domain ILCs due to the lack of uncertainty quantification. This critical limit was removed in the inversionbased iterative control (IIC) techniques through a frequency-domain formulation. The existing IIC techniques, however, is limited to single-input-single-output (SISO) systems, and the time-domain properties of the IIC techniques are not clear. The contribution of this article is: First, the IIC technique is extended from SISO systems to multi-input-multi-output systems, and the convergence condition is analyzed. Secondly, the time-domain properties of the MAIIC law are discussed. It is shown that the set of tractable frequencies is characterized by the bounds of system uncertainty that are quantifiable in practices, and the truncated MAIIC input-output convergences to the neighborhood of the desired input-output truncated in time, where arbitrarily small tracking error can be obtained by having a large enough truncation time. The proposed MAIIC technique is illustrated in a 3-D nanopositioning experiment using piezoelectric actuators.

Proper selection of metal roof-to-wall connectors is needed to provide a cost-effective load path to transfer uplift loads on a roof system down to the supporting walls and transfer lateral loads into and out of the roof diaphragm of light frame wood structures. Structural engineers, architects and builders rely upon published design values in catalogs, software, and websites provided by individual manufacturers to aid in the appropriate selection of connectors once the determination has been made for the required capacities of the connector. To date, the state-of-the-practice for dealing with multi-axis loads in these connectors is to use a linear unity equation based on uni-axis design values. However, no significant validation of this practice is to be found in the literature. This study experimentally examines three very common connector types under both bi-axis and tri-axis loads and helps to understand the behavior of such connectors under multi-axis loads. After testing over 350 connections and performing detailed analyses, the currently used design equation is found to be inefficient (has the least usable design space compared to other considered design equations) and overly conservative. Based on the criteria of efficiency, performance and safety, a design space using either the linear unity equation or by simply taking a 25% reduction on all allowable loads is proposed. The proposed design space for the three types of connectors is shown to have a high level of safety and adequate performance while providing up to 2.5 times the usable design space as compared with the current practice.

Real-world whole-body vibration exposures comprise motion in fore-aft, lateral, and vertical directions simultaneously. There can also be components of roll, pitch, and yaw. If evaluating vibration with respect to human response, most investigators will use methods defined in ISO 2631-1. This uses frequency weightings that were originally derived from laboratory studies of the subjective responses to vibration in one direction at a time. This paper describes experiments that were carried out using a 6 degree-of-freedom vibration simulator to validate the applicability of ISO 2631-1 in multi-axis environments. Fifteen subjects were exposed to 87 stimuli comprising single-axis, dual-axis, and tri-axial random vibration, to which they were required to produce subjective ratings. It is shown that in this study the root-sum-of-squares method of summation of subjective ratings in individual axes was an adequate technique for prediction of subjective rating of multi-axis vibration. Better agreement between objective and subjective measures of vibration was obtained for unweighted vibration than for frequency weighted signals. The best agreement for this study was achieved when axis multiplying factors were set at 2.2 and 2.4 for x- and y-axis vibration, respectively. Different values could be appropriate for other postures, seats, and vibration conditions and should be determined in future studies.

This paper describes an interpolation algorithm in the multi-axis motion control system, which can achieve six-axis interpolation operations, greatly improving the processing efficiency. Using modular design idea on the Quartus II platform, by DDA interpolation theory, interpolation modules are built through VHDL. And these interpolator modules are connected into schematic diagrams. By those schematic diagrams a linear interpolator, a circular interpolator and a composite interpolator are formed. The corresponding functions of those interpolators have been simulated on the Quartus II platform. The simulation shows that this interpolation algorithm is effective to complex multi-axis motion control system.

Train passengers often read newspapers while traveling. Vibration is one of the key factors that may occasionally inhibit this activity. An experimental study was, therefore, conducted to investigate the extent of interference perceived in reading task by seated subjects in two postures under random vibration. 30 healthy male subjects were exposed to vibration magnitudes of 0.4, 0.8 and 1.2 m/s2 in mono, dual and multi axis in the low frequency range 1–20 Hz. The task required subjects to read a given paragraph of Hindi national newspaper, in two seated postures (lap posture with backrest support and table posture with leaning over the table). The reading performance was evaluated by both degradation in performance in terms of time required to complete the task and subjective rating using Borg CR10 scale. Both the methods of reading performance evaluation exhibit progressive increase with an increase in vibration magnitude for both the subject postures in all the direction of vibration and are found to be higher in lateral and vertical direction among mono axes. The effects of multi axis vibration on perceived difficulty have been found to be similar to dual axes vibration and greater than mono axes vibration; however degradation in reading performance in multi axis vibration was also found to be similar to that for lateral direction. A comparison of the effect of postures by both evaluation methods revealed that the reading performance was adversely affected for table posture in all direction of vibration, however for lap posture, only the X-axis vibration effect was more severe. Relevance to industry Available ride comfort standards for vehicles do not include the effects of vibrations on passenger activities. Assessment of activity discomfort would be useful for vehicle design optimization to facilitate activity comfort.

We design a rapid positioning multi-axis and multi-blade saw machine in order to meet the processing needs of outer ply of engineered wood flooring and wood shutters in China. The machine uses two sets of saws against cutting in the cutting width, so its saw blade is thin, cutting loss is small and cut-turn percentage is high. Meanwhile, it has the feature of rapid positioning, convenient operation and high precision machining, which provides ideal processing equipment for China sheet production.

This paper proposes a multi-axis projection (MAP) based giant component formation strategy via the Maximal Independent Set (MIS) in a random unit-disk graph. We focus on the problem of virtual backbone construction in wireless ad hoc and sensor networks, where the coverage areas of the nodes are disks with identical radii. In the simulation, we show that the MAP-based giant component has the ability to connect most nodes and serves as a backbone in the network. The algorithm is localized and may play an important role in efficiently constructing a virtual backbone for ad hoc and sensor networks.

This article proposes a co-simulation platform concerning both mechanical and control subsystems, in order to test the dynamic performance of the welding machine. Two welding trajectories, before and after smoothing, are conducted in the simulation platform and welding practice to study the influence among smoothness, space precision and welding quality. Meanwhile, a series of welding trajectories are used to examine the spatial error of tool path motion by simulation in the platform. Results indicate that, the feed rate increases so high, beyond the dynamic characteristic of machine tool that induced undesirable oscillation of welding velocity and acceleration, as well as increased spatial error.

Now, the complication and systemization of the industry is increasing day after day, which make it hard to design the motion control system. However, the technology of field control is increasing, and the motion control system based on the network is widely used. The company of beck Hoff introduced the Ether CAT network, which can be configured easily, and the speed of communication is high, and in some way, the technology has become the focus of the studying the automation. This paper analyst the application for the Ether CAT in the multi-axis motion control system.

In this paper, a design system combining clinical experience and engineering knowledge was developed for the manufacture of custom-made femoral stem. The medical image of the hip obtained according to the patient X-rays. The geometric parameters for femoral stem were established based on the canal flare index. The necessary constrains based on surgical experience were integrated into the CAD system. The rapid prototyped model was built as the reference for review. Through the application of CAM software, the interference-free toolpath and the cutter location for multi-axis NC machining are generated. In order to establish the interface between the design and the manufacture of femoral stem, the postprocessor for multi-axis machine tool is developed. The cutting simulations with solid model are performed to verify the generated toolpath. It is also verified through the trial-cut with model material on a five-axis machine tool.

Titanium alloy impeller is hard in material, with large curvature and complex shape, all these factors increase its manufacturing difficulty and machining cost. By formulating the corresponding process plan, the three-axis and five-axis NC machining are combined, and the phased processing mode is implemented. The cutting tools of different lengths are selected according to the needs, and the reasonable processing strategy and cutting parameters are selected. The experimental results show that the processing time of the titanium alloy impeller is reduced effectively, the cost of manufacturing is reduced, and the processing quality is improved.

Toolpath generation for a multi-axis medical machine tool is a challenging task. In surgical procedures, it is difficult to apply industrial CAM technology owing to the requirement for quick toolpath generation and the likelihood of tool interference with complex structures of the target area. The objectives of this study are to optimize the initial position and posture of the cutting tool for performing the ideal skin incision and to minimize contact between the cutting tool and the surrounding area. We propose a novel toolpath strategy based on geometric models. It can be potentially applied to general machine-assisted surgeries.

Researched on the multi-axis CNC Integrated machining method of blade on large Francis turbine based on UG to automatic programming software architecture. Discussed the way to enhance the quality and to promote efficiency of machining .The key technology of five-axis CNC programming to large sculptured surface in hydro turbine's blade was introduced, which establishing 3-D model and tool-path generation and cutting simulation with small force, high precision and low cost. we have introduce this machining method and hope it is helpful to machining of similar parts.

On the basis of the ball-end milling feature during high-speed machining impeller, the relationship between cutting force and chips is analyzed in this paper. The model of ball-end milling cutter cutting force is founded through differential method. And the coefficients solution of cutting force model is expounded. Besides, the coefficients solution and the cutting force model simulation are implemented by the software Matlab.

We study the transformation of multi-axis Laguerre–Gaussian beams from optical beams comprising Hermite–Gaussian modes with ray–wave duality. By use of cylindrical lenses, Hermite–Gaussian modes can be transformed into Laguerre–Gaussian modes possessing optical orbital angular momentum. The superposed Hermite–Gaussian modes localized on geometric trajectories are generated from a degenerate hemiconfocal cavity and transformed into multi-axis Laguerre–Gaussian beams. Experimental results of the structured beams are systematically manipulated and in good agreement with theoretical analyses.

In recent years, ultraprecision micromachining technology draws wide attention. In particular, multi-axis control ultraprecision machine tools are playing an important role in producing complicated microparts made of a variety of materials. In addition, CAM software is also an essential element to control these machine tools. The paper deals not only with the current state of multi-axis control ultraprecision machine tools but also with the manufacture of two workpieces consisting of complicated shapes by means of micromilling.

Whole-body vibrations in trains are known to affect the performance of sedentary activities such as reading, writing, sketching, working on a computer, etc. The objective of the study was to investigate the extent of disturbance perceived in sketching task by seated subjects in two postures under mono- and multi-axis Gaussian random vibration environment. The study involved 21 healthy male subjects in the age group of 23—32 years. Random vibrations were generated both in mono- and multi-axial directions in the frequency range of 1—10 Hz at 0.5, 1.0, and 1.5 m/s2 rms (root mean square) amplitude. The subjects were required to sketch given geometric figures such as a circle, triangle, rectangle, and square with the help of ball-point pen under given vibration stimuli in two postures (sketch pad on lap and sketch pad on table). The deviation in distortion with respect to the given figure is represented in terms of percentage distortion. The influence of vibrations on the sketching activity was investigated both subjectively and by two specifically designed objective methods, namely, RMS (root mean square methodology) and area methods. The judgements of perceived difficulty to sketch were rated using seven-point semantic judgement scale. The percentage distortion and difficulty in sketching activity increased with an increase in vibration magnitude. Both subjective evaluation and the RMS method revealed that the task was affected more while sketching on the table. The percentage distortion was affected similarly and maximum in all the vibration directions except for the vertical, while sketching difficulty was found to be higher only with longitudinal and multi-axis vibration direction. The subjective evaluation also revealed that there was no effect of the type of entity chosen on the sketching difficulty.

A novel methodology was developed and implemented for error characterization, evaluation, and its quantification in a rotary joint of multi-axis machine tools by using a calibrated double ball bar (DBB) system as a working standard. This methodology greatly simplified the measurement setup and accelerated the error quantification. Moreover, the methodology is observed to be highly economical by reducing the tooling and instrumentation. However, considerable time and little more efforts are required in measuring and computing the errors. The developed methodology is capable of evaluating the five degrees of freedom (DOF) errors including two radial errors, one axial error, and two tilt errors out of six DOF error components of rotary joints. A DBB system with point accessory was used for direct measurement by change of length at multi-points and various locations, whereas mathematical modeling technique was implemented, and equation solvers were exercised for error evaluation and its quantification. Validation and authentication of the methodology and results obtained were carried out by simulation process prior to implementing the methodology on rotary joints of a five-axis turbine blade grinding machine. The results obtained from “A” and “B” rotary joints of the turbine blade grinding machine were presented by applying cubic spline technique for error modeling and its further utilization. The methodology was found extremely pragmatic, quite simple, efficient, and easy to use for error characterization and its quantification in rotary joints of multi-axis machine tools.

This research deals with tool compensation and postprocessor development for numerical control application. The content consists of three main activities. First, derives a cutting location expression of the tool for compensation and machining stability use. Second, establishes an analytical methodology to develop a kinematics transformation algorithm (KTA) for the specific type machine with a swivel spindle head and two rotary tables. And last, defines correspondent between workpiece and the cutter to attain the aim of three-dimensional tool compensation and presents postprocessors under KTA for two types of five-axis machine centers in examples.

Having studied the synchronized multi-axis control servo system, some type automatic wire striping and terminal crimping system is developed in the paper. In order to realize the precise and efficient synchronized multi-axis control, the PVT (Position-Velocity-Time) algorithm is adopted. This algorithm allows user to specify the time interval of each axis’ motion segment, so the multi-axis working sequence can be easily established in a tight way which augments the system processing speed and guarantees the system stability. Besides, by specifying the position and speed value at the processing point, the positioning accuracy and speed requirement at the processing point can be reached. In the design of the system control software, the modularization design is employed. This modularization idea simplifies the complex software design and allows people use the software more easily. Finally, the experimental result shows the system has a good synchronization performance, and meets the requirements of high efficiency, stability and positioning accuracy in practical production.

In order to manufacture geometrically complex or hard material parts, a new kind of multi-axis electro-discharge machining (EDM) computer numerical control (CNC) system, which is based on RT-Linux platform, was presented. Dual-kernel structure of System is adopted: Linux and RT-Linux are used to realize Time-sharing tasks and Real-time tasks separately. The system is divided macroscopically into two parts: Real-time part and Time-sharing part, microcosmically into three modules: Real-time Control Module, Drive Module and CNC User Module. Through the communications among them, three modules construct the whole system. Rimed Turbine Blisk was experimentalized to validate the performance of the system. The process and the results implied that the system is Real-time, stable and reliable.

In order to improve machining quality and productivity of complex curved surfaces in high-speed wire electrical discharge machining (HS-WEDM), an additional numerical control (NC) worktable (rotation-swing-swing worktable) and its NC system were designed. The movement model of the four-axle linkage system was established and simulation was developed using the programming language Visual C++ and standard connection software OpenGL.

Tool interference causes serious damage to surrounding soft tissue in minimally invasive orthopedic surgery with a milling robot. The objective of this study is to avoid the collision of cutting tool with complicated shapes, and a novel approach of interference-free toolpath generation in a short intraoperative time is proposed. In order to resolve this issue, we propose the following two methods: intraoperative modeling of soft tissues as an interference area and interference-free toolpath generation based on the model. A model is constructed to represent the opening area and the internal tissues by using a 3-dimensional optical position sensor to measure them. Based on the constructed model, interference-free toolpath is immediately determined by the preliminary definition of evacuating direction. The effectiveness of the proposed method is evaluated with artificial models on the system that the authors have developed so far. A tool contact force against the model was measured by a force sensor mounted on the cutting tool. The result revealed that the tool interference was greatly reduced by implementing the proposed method.

Micro/nano milling tools are usually made of ultra hard materials. Wire EDM (electrical discharge machining) may be the best choice to fabricate these tools conveniently and efficiently. For micro/nano milling tools with complicated three-dimensional (3D) geometries, manually programming method is not applicable. The CAM (computer-aided manufacturing) systems existing in the market don't take the special WEDM (Wire EDM) processes for micro/nano milling tools into consideration. In order to generate the NC programs automatically for the multi-axis WEDM machine to fabricate micro/nano milling tools, a computer assistant system, also called the CAM system, is developed in this paper. The CAM system takes the special WEDM processes into consideration for the fabrication of micro/nano milling tools. First, based on the interfaces and the databases of the CAM system, geometries of micro/nano milling tools, machining conditions for different portions of the tools, WEDM machine tool specifications and controller ...