A Novel Five-Degree-of-Freedom Parallel Manipulator and Its Kinematic Optimization

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Yimin Song ◽  
Binbin Lian ◽  
Tao Sun ◽  
Gang Dong ◽  
Yang Qi ◽  
...  
Keyword(s):  
Design Method ◽  
Dynamic Performance ◽  
Parallel Manipulators ◽  
Flow Path ◽  
Degree Of Freedom ◽  
Numerical Control ◽  
Dimensional Synthesis ◽  
Nsga Ii ◽  
Executive Mechanism ◽  
Five Axis

Driven by requirements of five-axis numerical control (NC) machine for its executive mechanism, this paper creatively proposes a flow path to synthesize a novel class of n-degree-of-freedom (n-DoF, 4 ≤ n ≤ 6) parallel manipulators (PMs) resorting to four steps, and takes a patented 5-DoF PM, named T5, for example to demonstrate the flow path in depth. Comparing with existing five-axis executive mechanisms, this novel class of the PMs has some advantages of light end-effector, good static, dynamic performance, and so on. Upon the underlying architecture of T5, the kinematic analysis and optimal design are carried out for the first time, in which two essential procedures are involved, one is the kinematic performance index by means of the reciprocal product associated with the wrench screw and twist screw with specific physical meaning, the other is the design method adopted to perform the multi-objective dimensional synthesis using an artificial intelligence approach, that is nondominated sorting genetic algorithm II (NSGA-II). This paper is aimed at laying a solid theoretical and technical foundation for the prototype design and manufacture of T5 PM.

Integrated optimal design of a high-speed planar parallel manipulator

2018 ◽  
Vol 233 (9) ◽  
pp. 2976-2990 ◽  
Author(s):  
Zhengsheng Chen ◽  
Minxiu Kong
Keyword(s):  
Optimal Design ◽  
Parallel Manipulator ◽  
High Speed ◽  
Design Method ◽  
Tracking Error ◽  
Dimensional Synthesis ◽  
Tracking Accuracy ◽  
Nsga Ii ◽  
Parameters Tuning ◽  
Planar Parallel Manipulator

To obtain excellent comprehensive performances of the planar parallel manipulator for the high-speed application, an integrated optimal design method, which integrated dimensional synthesis, motors/reducers selection, and control parameters tuning, is proposed, and the 3RRR parallel manipulator was taken as the example. The kinematic and dynamic performances of condition number, velocity index, acceleration capability, and low-order frequency are taken into accounts for the dimensional synthesis. Then, to match motors/reducers parameters and keep an economical cost, the constraint equations and the parameters library are built, and the cost is chosen as one of the optimization objectives. Also, to get high tracking accuracy, the dynamic forward plus proportional–derivative control scheme is introduced, and the tracking error is chosen as one of the optimization objectives. Hence, the optimization model including dimensional synthesis, motors/reducers selection and controller parameters tuning is established, which is solved by the genetic algorithm II (NSGA-II). The result shows that comprehensive performances can be effectively promoted through the proposed integrated optimal design, and the prototype was constructed according to the Pareto-optimal front.

Design, control and optimization of multi-degree-of-freedom spherical induction motor

2021 ◽  
pp. 095440622110007
Author(s):  
Ping Liu ◽  
Tao Deng ◽  
Zhenhua Su ◽  
Lu Jiang ◽  
Zhentao Ding
Keyword(s):  
Induction Motor ◽  
Optimization Design ◽  
Dynamic Performance ◽  
Structural Complexity ◽  
Element Model ◽  
Degree Of Freedom ◽  
Nsga Ii ◽  
Linear Induction Motor ◽  
And Control ◽  
Rotor Structure

In order to meet the requirements of multi-degree-of-freedom (multi-DOF) driving units for omnidirectional vehicle wheels, a multi-DOF spherical induction motor (SIM) is proposed with composite rotor through the conversion of design concept of linear induction motor (LIM), which compensates for the insufficiency of traditional multi-DOF driving scheme with structural complexity, control difficulties and poor dynamic performance. The SIM realizes two DOF driving and has the characteristics of direct output on rotor surface. Firstly, the overall design of SIM is drafted, as well as finite element model and control system are established. Subsequently, in order to optimize SIM performance, the multi-objective optimization design of composite rotor structure is proposed by adopting non-dominated sorting genetic algorithm-II (NSGA-II). The results show that the reasonable design of rotor structure can effectively improve output torque and reduce fluctuation. And the proposed design idea based on theory of LIM can provide a reference for SIM design.

Visualized Analysis and Simulation Research on Dynamic Performance of the Whole NC Machine Tool

2010 ◽  
Vol 118-120 ◽  
pp. 815-819
Author(s):  
Bo Wang ◽  
Wei Sun ◽  
Yan Chen ◽  
Le Tang ◽  
Bang Chun Wen
Keyword(s):  
Machine Tool ◽  
Performance Optimization ◽  
Design Method ◽  
Dynamic Performance ◽  
Digital Design ◽  
Design Flow ◽  
Numerical Control ◽  
Visual Design ◽  
Simulation Research ◽  
Nc Machine

The dynamic performance of numerical control (NC) machine is not only basis of evaluation for the vibration resistance and stability, but also theory basis of optimizing dynamic performance, and improving processed quality. As digital design method, visual design realizes "visibility" during the whole design process, increases design efficiency and guarantees the quality, which make visual design preferred design method in large mechanical engineering. In this paper, the analysis of dynamic performance on NC machine and visual design method will be integrated, taking a NC machining center built by Shenyang machine tool group as a study case, the dynamic visual design flow to be proposed, including the design purpose, content and design methods, finally, the dynamic performance of visual simulation we have done, taking the strength, inherent characteristics and harmonic response into account, offers the foundation about structural performance optimization on the machine.

Robust Two-degree-of-freedom Control Based on H∞ Method for PMSM Drive System

2020 ◽  
Vol 13 (4) ◽  
pp. 496-506
Author(s):  
Qixin Zhu ◽  
Lei Xiong ◽  
Hongli Liu ◽  
Yonghong Zhu ◽  
Guoping Zhang
Keyword(s):  
Control System ◽  
Control Theory ◽  
Position Control ◽  
Dynamic Performance ◽  
Servo System ◽  
Degree Of Freedom ◽  
Trade Off ◽  
Standard Design ◽  
Position Controller ◽  
Two Degree Of Freedom

Background: The conventional method using one-degree-of-freedom (1DOF) controller for Permanent Magnet Synchronous Motor (PMSM) servo system has the trade-off problem between the dynamic performance and the robustness. Methods: In this paper, by using H∞ control theory, a novel robust two-degree-of-freedom (2DOF) controller has been proposed to improve the position control performance of PMSM servo system. Using robust control theory and 2DOF control theory, a H∞ robust position controller has been designed and discussed in detail. Results: The trade-off problem between the dynamic performance and robustness which exists in one-degree-of-freedom (1DOF) control can be dealt with by the application of 2DOF control theory. Then, through H∞ control theory, the design of robust position controller can be translated to H∞ robust standard design problem. Moreover, the control system with robust controller has been proved to be stable. Conclusion: Further simulation results demonstrate that compared with the conventional PID control, the designed control system has better robustness and attenuation to the disturbance of load impact.

scholarly journals Multi-Objective Lightweight Optimization of Parameterized Suspension Components Based on NSGA-II Algorithm Coupling with Surrogate Model

Machines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 107
Author(s):  
Rongchao Jiang ◽  
Zhenchao Jin ◽  
Dawei Liu ◽  
Dengfeng Wang
Keyword(s):  
Ride Comfort ◽  
Lightweight Design ◽  
Dynamic Performance ◽  
Vehicle Dynamic ◽  
Multi Objective Optimization ◽  
Original Design ◽  
Dynamic Simulations ◽  
Nsga Ii ◽  
Torsion Beam ◽  
Multi Objective

In order to reduce the negative effect of lightweighting of suspension components on vehicle dynamic performance, the control arm and torsion beam widely used in front and rear suspensions were taken as research objects for studying the lightweight design method of suspension components. Mesh morphing technology was employed to define design variables. Meanwhile, the rigid–flexible coupling vehicle model with flexible control arm and torsion beam was built for vehicle dynamic simulations. The total weight of control arm and torsion beam was taken as optimization objective, as well as ride comfort and handling stability performance indexes. In addition, the fatigue life, stiffness, and modal frequency of control arm and torsion beam were taken as the constraints. Then, Kriging model and NSGA-II were adopted to perform the multi-objective optimization of control arm and torsion beam for determining the lightweight scheme. By comparing the optimized and original design, it indicates that the weight of the optimized control arm and torsion beam are reduced 0.505 kg and 1.189 kg, respectively, while structural performance and vehicle performance satisfy the design requirement. The proposed multi-objective optimization method achieves a remarkable mass reduction, and proves to be feasible and effective for lightweight design of suspension components.

scholarly journals Study of Machining of Gears with Regular and Modified Outline Using CNC Machine Tools

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral
Keyword(s):  
Machine Tools ◽  
Coordinate Measuring Machine ◽  
Optical Microscope ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cylindrical Gears ◽  
Measuring Machine ◽  
Five Axis

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.

Finite Element Analysis and Optimization of Long-Span Gantry NC Machining Center Structure

2011 ◽  
Vol 346 ◽  
pp. 379-384
Author(s):  
Shu Bo Xu ◽  
Yang Xi ◽  
Cai Nian Jing ◽  
Ke Ke Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Design Method ◽  
Dynamic Performance ◽  
Plate Thickness ◽  
Element Model ◽  
Wall Structure ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
Dynamic Performance Analysis

The use of finite element theory and modal analysis theory, the structure of the machine static and dynamic performance analysis and prediction using optimal design method for optimization, the new machine to improve job performance, improve processing accuracy, shorten the development cycle and enhance the competitiveness of products is very important. Selected for three-dimensional CAD modeling software-UG NX4.0 and finite element analysis software-ANSYS to set up the structure of the beam finite element model, and then post on the overall structure of the static and dynamic characteristic analysis, on the basis of optimized static and dynamic performance is more superior double wall structure of the beam. And by changing the wall thickness and the thickness of the inner wall, as well as the reinforcement plate thickness overall sensitivity analysis shows that changes in these three parameters on the dynamic characteristics of post impact. Application of topology optimization methods, determine the optimal structure of the beam ultimately.

scholarly journals Parallel Robot Translational Performance Evaluation through Direction-Selective Index (DSI)

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
G. Boschetti ◽  
R. Rosa ◽  
A. Trevisani
Keyword(s):  
Performance Evaluation ◽  
Performance Index ◽  
General Framework ◽  
Dynamic Performance ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Performance Indexes ◽  
Definition Of ◽  
Performance Variations

Performance indexes usually provide global evaluations of robot performances mixing their translational and/or rotational capabilities. This paper proposes a definition of performance index, called direction-selective index (DSI), which has been specifically developed for parallel manipulators and can provide uncoupled evaluations of robot translational capabilities along relevant directions. The DSI formulation is first presented within a general framework, highlighting its relationship with traditional manipulability definitions, and then applied to a family of parallel manipulators (4-RUU) of industrial interest. The investigation is both numerical and experimental and allows highlighting the two chief advantages of the proposed DSIs over more conventional manipulability indexes: not only are DSIs more accurate in predicting the workspace regions where manipulators can best perform translational movements along specific directions, but also they allow foreseeing satisfactorily the dynamic performance variations within the workspace, though being purely kinematic indexes. The experiments have been carried out on an instrumented 4-RUU commercial robot.

Modular Design Technology of Multi-DOF Mechanical Arm

2014 ◽  
Vol 599-601 ◽  
pp. 358-361
Author(s):  
Huan Qiang ◽  
Hu Zhang ◽  
Yan Zhou
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Structure Design ◽  
Degree Of Freedom ◽  
Dynamics Simulation ◽  
Complicated Structure ◽  
Design Technology ◽  
Structure Line ◽  
Six Dof

A design method of modular joint is proposed according to the complicated structure, line exposed and heavier characteristics of multi-DOF (degree of freedom) mechanical arm. In this paper, the design of modular joint was carried on and a model of six-DOF mechanical arm was built through the research on the structure of mechanical arm. On this basis, dynamics simulation will be carried. The results show that the modular design method simplified the structure of the mechanical arm, the dynamics simulation proved it was feasible for the structure design and drive selection.

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