Jia Xie

Position servo control of the slider in double toggle mechanical press using Bezier curve model and fuzzy control

Servo press is more flexible for forming process than conventional press. The position control of the slider is the key technique in the servo presses. In order to achieve an excellent position control performance of the slider, a position servo control strategy of the slider in a servo press - double toggle mechanical press is proposed in this paper. The control strategy combines the Bezier curve model and the fuzzy control methods. Firstly, the controlled mechanical object is described. Then, a Bezier curve model is established to accurately describe the control curves. Based on this Bezier curve model, the position servo control given curves of the crank for different processes are obtained. Afterwards, transverse flux machine (TFM) is selected as the servo motor for the control system because of its high force densities. Since TFM has complex nonlinear features, a Fuzzy-Proportional-Integral (fuzzy-PI) control method is presented to control the crank position for tracking the given curves. At last, the tracking curves for different processes are obtained. The results show that the control strategy can effectively achieve the flexible manufacturing of the press.

Optimum Design of Transverse Flux Machine for High Contribution of Permanent Magnet to Torque Using Response Surface Methodology

Transverse flux machine (TFM) has been proved to be very suitable for high-torque, lowspeed, and direct-drive situation in industry. But the complex structures and costly permanent magnets (PMs) are two key limitations of its wide range of applications. This paper proposes a new claw pole TFM (ACPTFM) which features an assembled claw pole stator and using the lamination steels material to overcome the complex structures. By combining response surface methodology (RSM) with design of experiment, an optimum design method is put forward to improve the PM’s contribution to the torque in order to save the PM’s amount. The optimum design results demonstrate the validity of the proposed optimum design method and the optimized model. Eventually, the finiteelement analysis (FEA) calculation method, which is used in the optimization process, is verified by the experiments in a prototype.

Design and analysis of flux concentrating permanent magnet disc synchronous motor for direct driving system

Direct driving system is a dominant development direction in the modern electromechanical system, and the permanent magnet disc synchronous motor (PMDSM) is considered as an attractive alternative for its high efficiency and torque density. In this paper, a novel PMDSM characterized by flux concentrating with fractional slot and concentrated winding is presented firstly, then the process of design and analysis of the motor is introduced to gain the optimal structure dimension for minimum cost price. Compared with the surface-mount PMDSM, the motor has better output performance.

Research on key techniques of green mechanical press directly driven by transverse flux machine

A novel driving system of mechanical press is proposed for achieving green production equipment by direct drive technology. Its major parameters are analyzed and defined. The motor suitable for direct drive applications in the new system plays a crucial role, so transverse flux machine (TFM) is an ideal alternative for its high force densities. A new design of TFM which features a unique configuration that is composed of assembled stators and flux-concentrating rotor is proposed. It exhibits low manufacturing costs and meets high torque, low speed applications. 3-D FEA based optimization is used to define new TFM important parameters. The driving system of green mechanical press is very simple and it achieves a reduction of 30% of the energy losses compared with that of JB23-63 mechanical press which is the initial equipment of the new design.

Torsional Vibration Analysis for Large-Scale Reciprocating Compressor Crankshaft

This paper presents a new method which combined multi-body dynamics theory and finite element technology to calculate transient stress of the crankshaft of the large-scale reciprocating compressor. On the basis of multi-body dynamics theory, the kinematical simulation of the crankshaft, the connecting rod, the piston and other components were performed, and thus to get the vibration modal of the crankshaft. So we can judge whether the crankshafts torsional resonance will happen, as well as get the real loads on the crankshaft when it worked. Then the transient stress of the crankshaft can be calculated using finite element technology. Comparing to traditional stress calculating methods, this new method not only considers the variable inertia which caused by reciprocating masss movement, but also can calculate the integrated vibration stress of crankshaft in three directions, including torsion, lateral and axial. Therefore, this method can describe dynamic characteristics of the crankshaft more accurately and more entirely.

The Analysis of Motion and Strength for the Clamping Mechanism of Die-Casting Machine Weighing 4500 Ton

The clamping mechanism motion condition of die-casting machine is very important to the whole die-casting machine. In order to analyze the relationship between the output force of clamping mechanism and displacement of hydraulic cylinder, the whole clamping mechanism model is established. By the software ADAMS (Automatic Dynamic Analysis of Mechanical System) simulation, the all kinds of characteristics are got. Through the comparison, the best displacement by the output force is derived. In the end, on the basis of the result of the analysis, the stress condition of clamping mechanism confirms the rationality.

Hybrid Control Using Sampling PI and Fuzzy Control Methods for Large Inertia and Time Delay System

In this paper, a hybrid control strategy for large inertia and time delay system was proposed. The proposed hybrid control strategy combines the sampling PI control and the linear control methods together. Respectively, the sampling PI control method is used to overcome the disadvantages of the control problems which are caused by the large inertia and time delay; while the linear control method is applied to achieve stable control of the steady-state control process and improve the system robustness. Since the parameters of the linear control are varied in the control process, the fuzzy control method is utilized to get the optimal parameters so that can realize the effective control. The hybrid control strategy is implemented and practically applied to a large inertia and time delay system — cement mill in a cement plant. The practical control results illustrate that feasibility the proposed strategy both effective and implemental.

Optimum Design of Toggle Transmission System in Double Toggle Mechanical Press Using Response Surface Methodology Combined with Experimental Design

In order to minimize the velocity fluctuation of the slider in the stage of workpiece processing, an optimum design of toggle transmission system in double toggle mechanical press is presented in this paper. Experimental design is used to arrange the experiment procedure and all the experimental samples are obtained from Adams analysis model. Response Surface Methodology (RSM) is used as an optimization method. The validity of this method is verified by comparing the optimized model to the initial model.

Slider Position Servo Control of the Double Toggle Mechanical Press Directly Driven by Transverse Flux Machine

A slider position servo control system of the double toggle mechanical press is presented in this paper. The controlled mechanical object is described, and the velocity controller and position controller are designed. A claw pole transverse flux machine is used as the servo motor in the control system for its high torque and low speed characteristics. The results of the slider’s motion curves are obtained, which show that the control system effectively achieves the flexible manufacturing of the press.