scholarly journals Design and Properties of Octaslide Redundant Parallel Kinematics

10.14311/568 ◽  
2004 ◽  
Vol 44 (3) ◽  
Author(s):  
V. Bauma ◽  
M. Valášek ◽  
Z. Šika

This paper describes the conceptual design process of OCTASLIDE redundant parallel kinematics for a machine tool. Redundantly actuated parallel kinematics is a recently developed new concept for machine tools. It enables all mechanical properties of machine tools to be improved several times simultaneously. This is particularly demonstrated on the design of the OCTASLIDE. This is a concept of a five-axis machine tool centre. The paper describes the critical initial design phases and the accessible mechanical properties. The design process has follow the newly developed design methodology for parallel kinematics machines.

10.14311/710 ◽  
2005 ◽  
Vol 45 (3) ◽  
Author(s):  
M. Valášek ◽  
V. Bauma ◽  
Z. Šika

This paper deals with possible new concepts for machine tools based on parallel kinematics for advanced manufacturing. Parallel kinematics machines (PKM) enable the mechanical properties of manufacturing machines to be improved. This has been proven by several new machine tool concepts. However, this potential can be and must be increased by applying the principle of redundant actuation. This paper deals with the extension of the concepts of redundantly actuated parallel kinematics structures for five-sided five-axis machine tools and for a free-forming sheet metal forming machine. The design principles of previous successful PKMs are summarized and new concepts are proposed. The most important requirement criteria are summarized. The proposed concepts are qualitatively and initially quantitatively evaluated according to these criteria. 


Author(s):  
Zhong Jiang ◽  
Jiexiong Ding ◽  
Qicheng Ding ◽  
Li Du ◽  
Wei Wang

Nowadays the five-axis machine tool is one of the most important foundations of manufacturing industry. To guarantee the accuracy of the complex surface machining, multi-axis linkage performance detection and compensation of five-axis machine tools is necessary. RTCP (Rotation Tool Center Point) is one of the basic essential functions for the five-axis machine tools, which can keep the tool center with the machining trajectory when five axes move synchronously. On the basis of RTCP function, a way to detect multi-axes linkage performance of five-axis machine tools is briefly introduced, and linkage error model is built in accordance with the topological structure of machine tool. Based on the feature of the linkage errors of the five-axis machine tool, the error tracing and compensation method is proposed. Some simulations and experiments that verify the error tracing method could locate the linkage error category are established. Therefore, a new attempt to detect and compensate the linkage error of the five-axis machine tool is provided in this paper.


Author(s):  
Jennifer Creamer ◽  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers ◽  
Philip L. Freeman ◽  
...  

This paper presents a geometric error compensation method for large five-axis machine tools. Compared to smaller machine tools, the longer axis travels and bigger structures of a large machine tool make them more susceptible to complicated, position-dependent geometric errors. The compensation method presented in this paper uses tool tip measurements recorded throughout the axis space to construct an explicit model of a machine tool's geometric errors from which a corresponding set of compensation tables are constructed. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. Two position-dependent geometric error models are considered in this paper. The first model utilizes a six degree-of-freedom kinematic error description at each axis. The second model is motivated by the structure of table compensation solutions and describes geometric errors as small perturbations to the axis commands. The parameters of both models are identified from the measurement data using a maximum likelihood estimator. Compensation tables are generated by projecting the error model onto the compensation space created by the compensation tables available in the machine tool controller. The first model provides a more intuitive accounting of simple geometric errors than the second; however, it also increases the complexity of projecting the errors onto compensation tables. Experimental results on a commercial five-axis machine tool are presented and analyzed. Despite significant differences in the machine tool error descriptions, both methods produce similar results, within the repeatability of the machine tool. Reasons for this result are discussed. Analysis of the models and compensation tables reveals significant complicated, and unexpected kinematic behavior in the experimental machine tool. A particular strength of the proposed methodology is the simultaneous generation of a complete set of compensation tables that accurately captures complicated kinematic errors independent of whether they arise from expected and unexpected sources.


Author(s):  
Peng Xu ◽  
Benny C. F. Cheung ◽  
Bing Li

Calibration is an important way to improve and guarantee the accuracy of machine tools. This paper presents a systematic approach for position independent geometric errors (PIGEs) calibration of five-axis machine tools based on the product of exponentials (POE) formula. Instead of using 4 × 4 homogeneous transformation matrices (HTMs), it establishes the error model by transforming the 6 × 1 error vectors of rigid bodies between different frames resorting to 6 × 6 adjoint transformation matrices. A stable and efficient error model for the iterative identification of PIGEs should satisfy the requirements of completeness, continuity, and minimality. Since the POE-based error models for five-axis machine tools calibration are naturally complete and continuous, the key issue is to ensure the minimality by eliminating the redundant parameters. Three kinds of redundant parameters, which are caused by joint symmetry information, tool-workpiece metrology, and incomplete measuring data, are illustrated and explained in a geometrically intuitive way. Hence, a straightforward process is presented to select the complete and minimal set of PIGEs for five-axis machine tools. Based on the established unified and compact error Jacobian matrices, observability analyses which quantitatively describe the identification efficiency are conducted and compared for different kinds of tool tip deviations obtained from several commonly used measuring devices, including the laser tracker, R-test, and double ball-bar. Simulations are conducted on a five-axis machine tool to illustrate the application of the calibration model. The effectiveness of the model is also verified by experiments on a five-axis machine tool by using a double ball-bar.


2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Song Gao ◽  
Jihong Chen ◽  
Shusheng Liu ◽  
Xiukun Yuan ◽  
Pengcheng Hu ◽  
...  

Abstract Due to their superior machining quality, efficiency, and availability, five-axis machine tools are important for the manufacturing of complicated parts of freeform surfaces. In this study, a new type of the five-axis machine tool was designed that is composed of four rotary axes as well as one translational axis. Given the structure of the proposed machine tool, an inverse kinematics analysis was conducted analytically, and a set of methods was then proposed to address the issues in the kinematic analysis, e.g., the singularity and multi-solution problems. Compared with traditional five-axis machine tools, which are typically composed of three linear axes and two rotary axes, the proposed machine tool exhibited better kinematic performance with machining parts with hub features, such as impellers, which was validated by simulations and real cuttings.


2014 ◽  
Vol 701-702 ◽  
pp. 874-878
Author(s):  
Shao Hsien Chen ◽  
Chin Mou Hsu ◽  
Kuo Lin Chiu ◽  
Chu Peng Chan

Swivel spindle head is a key component used in five-axis machine tool of high performance and is of great importance in application and design. Nowadays, more and more components are manufactured by high performance multi-axis CNC machine tools, such as components of spaceflight, renewable energy and automobile, etc. Therefore, high performance machine tools of multiple axes are more and more urgently demanded, while Swivel spindle head is one of the most important components for a multi-axis machine tool. Hence, Swivel spindle head is one of the key to developers multi-axis machine tool . The study explores the highly responsive direct-driving motor able to drive the spindle head to rotate with multi-driving rotary technology. The dual-driving motor rotates via multi-driving units, generates torsion that magnifies and eliminates its clearance, and then drives the spindle head to rotate. Results of the test show that the completed machine tool can meet the standards of dual axis rotary head with high preformation in, no matter, speed, distance, positional accuracy, repeated accuracy or maximum torque, etc.


2015 ◽  
Vol 794 ◽  
pp. 379-386 ◽  
Author(s):  
Bernd Kauschinger ◽  
Steffen Schroeder

The measures taken to improve the thermal behaviour of machine tools are based on thermal models. The models are applied to support the design process and to correct the machine tool operation in a control-based way. Especially the models for correction purposes include uncertain parameters that cannot be estimated with sufficient accuracy. Thus these parameters have to be adjusted by means of measurements. During the adjustment process, a broad diversity of machine behaviour and model characteristics has to be taken in to account. Therefore, substantial time, effort and expert knowledge are required. To identify the key expenses, a generalized and systematic analysis of the adjustment process was carried out. First, the typical design of the models, the parameters of the sub models and the current adjustment procedure were investigated. Based on the results of the analysis, support requirements were identified. Afterwards first methods and software tools for efficient support were developed. This strategy is demonstrated using the example of a hexapod strut model.


Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2260
Author(s):  
Chunhui Li ◽  
Zhiqiang Song ◽  
Xianghua Huang ◽  
Hui Zhao ◽  
Xuchu Jiang ◽  
...  

Dynamic parameters are the intermediate information of the entirety of machine dynamics. The differences between components have not been combined with the structural vibration in the cutting process, so it is difficult to directly represent the dynamic characteristics of the whole machine related to spatial position. This paper presents a method to identify sensitive parts according to the dynamic stiffness-sensitivity algorithm, which represents the dynamic characteristics of the whole machine tool. In this study, two experiments were carried out, the simulation verification experiment (dynamic experiment with variable stiffness) and modal analysis experiment (vibration test of five-axis gantry milling machine). The key modes of sensitive parts obtained by this method can represent the position-related dynamic characteristics of the whole machine. The characteristic obtained is that the inherent properties of machine-tool structure are independent of excitation. The method proposed in this paper can accurately represent the dynamic characteristics of the whole machine tool.


Author(s):  
Tzu-Chi Chan ◽  
Jyun-Sian Yang

Abstract With the development of machine tools trending toward high precision, intelligence, multi-axis, and high speed, the improvement of the processing performance and rigidity of the machine is considerably important. The objective of this study is to design of a high-speed five-axis moving-column machine tool and perform structural analysis and optimization. We study the static and dynamic characteristics of the five-axis machine tool, design and improve the mechanical structure, and optimize the structural configuration of the machine. The entire machine structure is further analyzed and enhanced to improve its static and dynamic characteristics, including static rigidity, modal, transient, and spectral response characteristics. The static and dynamic characteristics of the machine structure directly affect the machine processing performance, and further affect the work piece precision machined by the tool. Through this study, the design technology for speed, accuracy, and surface roughness of the machine tool are further improved.


2013 ◽  
Vol 7 (5) ◽  
pp. 473-473
Author(s):  
Editorial Office

The fourth Best Paper Award 2013 and the first Best Review Award 2013 ceremony was held in Kasumigaseki, Tokyo, Japan, on August 2, 2013, attended by the winner and IJAT committee members who took part in the selection process. The Best Paper was severely selected from among 81 papers published in Vol.6 (2012) and the Best Review was selected from 9 reviews published from 2010 to 2012. The Best Paper Award winner was given a certificate with a nearly US$1,000 honorarium and the Best Review Award winner was given a certificate with commemorative shield.   The Best Paper Award 2013 is as follows: Title: Estimation of Dynamic Mechanical Error for Evaluation of Machine Tool Structures Authors: Daisuke Kono, Sascha Weikert, Atsushi Matsubara, and Kazuo Yamazaki Int. J. of Automation Technology Vol.6 No.2, pp. 147-153, March 2012   The Best Review Award 2013 is as follows: Title: Indirect Measurement of Volumetric Accuracy for Three-Axis and Five-Axis Machine Tools: A Review Authors: Soichi Ibaraki and Wolfgang Knapp Int. J. of Automation Technology Vol.6 No.2, pp. 110-124, March 2012


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