Design of a Servo Mechanical Press with Redundant Actuation

A servo press is a new type of mechanical press that is driven by programmable motors and offers superior performance such as low noise, excellent efficiency and high precision for metal forming operations. Similar to multi-link mechanical presses, a servo mechanical press tends to grow in size as the tonnage increases that calls for larger, heavy duty servo motors, which could be expensive and may not even be available. In this paper, a new concept of servo mechanical press with redundant actuation is proposed firstly using two servo motors driving one input shaft, i.e. one-point-two-motor mode that makes it possible to produce a larger press with available servomotors. Then the punching mechanism design is detailed. The performance indices are set up including mechanical advantage reciprocal and link force ratios. A bounded feasible solution space is constructed for dimensional synthesis based on non-dimensional link lengths and assembly conditions. The performance atlases are depicted over the bounded feasible solution space that lead to a visual solution of the punching mechanism with global optimization. Finally, case studies are given to illustrate the design method with visual global optimization, and a prototype with 200 t punching force is being developed in our laboratory to demonstrate efficacy of the new concept for servo mechanical press. The presented research provides a feasible solution to the development of heavy-duty servo mechanical presses and finds potential applications in the development of other types of heavy equipments with electric drive.

Optimal Design of a Main Driving Mechanism for Servo Punch Press Based on Performance Atlases

The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed,high accuracy,high flexibility,high productivity,low noise,cleaning and energy saving.To effectively improve the performance and lower the cost,it is necessary to develop new mechanisms and establish corresponding optimal design method with uniform performance indices.A new patented main driving mechanism and a new optimal design method are proposed.In the optimal design,the performance indices,i.e.,the local motion/force transmission indices ITI,OTI,good transmission workspace good transmission workspace(GTW) and the global transmission indices GTIs are defined.The non-dimensional normalization method is used to get all feasible solutions in dimensional synthesis.Thereafter,the performance atlases,which can present all possible design solutions,are depicted.As a result,the feasible solution of the mechanism with good motion/force transmission performance is obtained.And the solution can be flexibly adjusted by designer according to the practical design requirements.The proposed mechanism is original,and the presented design method provides a feasible solution to the optimal design of the main driving mechanism for servo punch press.

Fuzzy iterative learning control of electro-hydraulic servo system for SRM direct-drive volume control hydraulic press

A new kind of volume control hydraulic press that combines the advantages of both hydraulic and SRM(switched reluctance motor) driving technology is developed.Considering that the serious dead zone and time-variant nonlinearity exist in the volume control electro-hydraulic servo system,the ILC(iterative learning control) method is applied to tracking the displacement curve of the hydraulic press slider.In order to improve the convergence speed and precision of ILC,a fuzzy ILC algorithm that utilizes the fuzzy strategy to adaptively adjust the iterative learning gains is put forward.The simulation and experimental researches are carried out to investigate the convergence speed and precision of the fuzzy ILC for hydraulic press slider position tracking.The results show that the fuzzy ILC can raise the iterative learning speed enormously,and realize the tracking control of slider displacement curve with rapid response speed and high control precision.In experiment,the maximum tracking error 0.02 V is achieved through 12 iterations only.

Phase-Division-Based Dynamic Optimization of Linkages for Drawing Servo Presses

Existing linkage-optimization methods are designed for mechanical presses; few can be directly used for servo presses, so development of the servo press is limited. Based on the complementarity of linkage opti- mization and motion planning, a phase-division-based linkage-optimization model for a drawing servo press is established. Considering the motion-planning principles of a drawing servo press, and taking account of work rating and efficiency, the constraints of the optimization model are constructed. Linkage is optimized in two modes： use of either constant eccentric speed or constant slide speed in the work segments. The performances of optimized link- ages are compared with those of a mature linkage SL4- 2000A, which is optimized by a traditional method. The results show that the work rating of a drawing servo press equipped with linkages optimized by this new method improved and the root-mean-square torque of the servo motors is reduced by more than 10%. This research pro- vides a promising method for designing energy-saving drawing servo presses with high work ratings.

Study of Dynamic Robustness of Servo Control System on a Water Press

The reliability and robustness of the electro-hydraulic servo control system for heavy-duty forging machine play an important role in forging processes. A mathematic model of 50 MN water press for free forging was created in this research. The dynamic robust compensator integrating with PID control method is designed and applied to the mathematical model simulation. The simulated results approved that the dynamic robust compensator application restrains interference from extra load and improves the electro-hydraulic position servo control system accuracy and stability.

Modelling and Simulation of System Dynamics of Hybrid-Driven Precision Press

Different from conventional mechanical systems with single degree of freedom (DOF), the main idea of the system of hybrid-driven precision press is to combine the motion of a constant speed motor with a servomotor via a two-DOF mechanism to provide flexible output. In order to make the feasibility clear, this paper studies theoretically the dynamic characteristics of this hybrid-driven mechanical system.Firstly,the dynamics model of the whole electromechanical system is set up by combining dynamic equations of DC motors with those of two-DOF nine-bar mechanism deduced by the Lagrange′s formula. Secondly through the numerical solution with the fourth Runge-Kutta, computer simulation about the dynamics is done, which shows that the designed and optimized hybrid-driven precision press is feasible in theory. These provide theoretical basis for later experimental research.

Application of direct torque control to electric screw presses for speeding up torque response and reducing starting current

Fast response and stable torque output are crucial to the performance of electric screw presses. This paper describes the design of a direct torque control （DTC） system for speeding up torque response and reducing the starting current of electric screw presses and its application to the J58K series of numerical control electric screw presses with a dual-motor drive. The DTC drive system encompasses speed control, torque reference control, and switching frequency control. Comparison of the DTC dual-AC induction motor drive with corresponding AC servo motor drive showed that for the J58K-315 electric screw press, the DTC drive system attains a higher maximum speed （786 r/min） within a shorter time （1.13 s） during a 250 nun stroke and undergoes smaller rise in temperature （42.0 ℃） in the motor after running for 2 h at a 12 min-1 strike frequency than the AC servo motor drive does （751 r/min within 1.19 s, and 50.6 ℃ rise）. Moreover, the DTC AC induction motor drive, with no need for a tachometer or position encoder to feed back the speed or position of the motor shaft, enjoys increased reliability in a strong-shock work environment.

数控压机伺服控制系统复合控制器I-ABC与PID优化

为了提高数控压机伺服控制系统的控制精度,针对伺服控制系统运行控制过程构建数学模型,在人工蜂群算法基础上融入了云分析模型,之后采用改进人工蜂群算法(Improved Artificial Bee Colony,I-ABC)调节比例-积分-微分(Proportional Integral Differential,PID)参数,建立了一种复合控制方法。研究结果表明:以I-ABC进行PID控制时,可以使幅度差降低到0.4%,相位差基本在-0.54°之内,系统加载精度也获得了明显提升,表现出了更优的跟踪性能。以I-ABC进行PID控制时,能够对多余力起到明显抑制作用,响应速度也获得明显提升,可以有效满足系统的准确控制要求。在系统内加入干扰信号,引入I-ABC实施PID调节可以减小系统超调量,还可以获得更短调节时间,使系统获得更强抗干扰性能。

基于指数趋近率的液压机泵控伺服系统滑模控制

滑模控制方法具备较强鲁棒性,控制器结构也较简单,被广泛应用于泵控电液伺服液压系统上。在分析泵控系统原理的基础上,为克服传统PID控制很难抵抗较强外部干扰力的缺点,泵控伺服系统建立指数趋近律滑模控制器,建立泵控伺服系统MATLAB/Simulink仿真。研究结果表明:正弦信号跟踪下,滑模控制最大稳态跟踪误差与PID相比降低83.4%,同时控制器IMSE指标相对PID控制器发生了显著降低。该研究有助于提高液压机运行效率,对提高产品质量具有一定的指导意义。

航天伺服关节轴承压装机的设计

目前伺服机构配套关节轴承的装配主要采用人工使用压力机完成,此方式需考验操作人员的熟练程度,操作依赖性较大,且装配效率较低,无法保证装配质量一致性;为了提高车间生产效率,提高车间自动化生产程度,提出了一种自动进出料的轴承压入工艺方法,即通过依托于三轴传动机械手自动进出料的轴承压入设备,优化传统依靠压力机装配方法。首先,对整体结构进行了设计,并介绍了工作原理;其次,对关键环节进行了研究,并对关键零件进行了校核;最后,对气动回路以及电气控制部分进行了介绍。压入设备工艺方法的提出,对提高车间轴承装配生产效率以及提高产品质量一致性具有重要的意义。

四轴联动热挤压成形液压机及伺服控制系统的应用

结合公司为国内某航空研究院研发的一台高精度四轴联动热挤压成形设备,详细阐述了伺服运动控制系统在同步轴中的运用,巧妙利用高频响阀的特性曲线,实现了碳纤维等复合材料的热压成形。本文重点分析该热挤压成形液压机的液压原理及其电控系统的实现。

一种多功能锻造液压机的控制系统与控制方法

近年锻造行业的快速发展,对锻件的要求越来越高,对锻造压机也提出了各种挑战,多功能锻造液压机应运而生,即在同一台液压机上实现铝合金、镁合金、钛合金和高温合金等制件的自由锻造、精密挤压锻造和等温锻造三种锻造工艺。本文主要对多功能液压机的控制系统与控制方法进行阐述。

伺服液压系统在榨油装置中设计与应用研究

本文阐述了一种双柱式承载式整体结构的液压榨油装置设计,通过采用伺服液压站精准控制流量和压力实现各项压榨需求,以及该设计在榨油装置中的应用。

传统机械压力机与伺服机械压力机实际工况下节能水平对比研究

本文采取理论分析与实验数据分析相结合的方法,通过比较当前生产中使用的主流设备(传统压力机与伺服压力机)在能耗方面的差异,探讨两类机械压力机在绿色节能方面的表现,分析其优缺点,并深入研究机械压力机对未来绿色低碳发展政策的适应性和发展方向。

基于热冲压生产线的12000kN数字机械伺服压力机关键技术及应用

本文探讨了基于数字机械伺服压力机的热冲压生产线的研究及应用。随着汽车轻量化和安全性能要求的提高,高强钢热冲压成形车身零部件的广泛应用成为汽车制造业的发展趋势。热冲压成形技术由于其成形性能和复杂构型成形能力,成为满足高强度钢车身结构件要求的重要选择。然而,传统热冲压生产线在满足高强度钢件成形要求上仍存在一定挑战。新一代热冲压生产线基于数字机械伺服压力机,采用先进的热冲压成形技术和自动化输送系统,能够满足大型复杂高强钢车身零部件对高强钢材料进行热冲压加工的需求,提高生产效率和产品质量。

机器人与伺服压力机控制应用研究

利用系统的非线性动力学,对机器人和工业伺服压力机机构进行了实例分析,并对机器人系统和伺服曲柄压力机进行了识别和仿真研究,获得了系统的动态行为。根据应用所要求的不同运动轨迹,在系统上研究了软计算技术,并且运用传统PID控制技术,通过PSO-NN(粒子群优化神经网络)、BP(反向传播)、PSOPID、PID、CasFF(级联前馈)等控制方法,实现了控制目的。

伺服压力机用飞轮电池蓄能系统参数计算方法探讨

飞轮电池作为伺服压力机的蓄能器的补充,可以回收伺服装备的制动能量,其主动控制输入输出功率的特性也可以保障设备运行总体功率消耗的平稳。本文针对飞轮电池应用于伺服压力机这一技术,对飞轮电池系统的参数的计算方法进行研究,为可控蓄能器在锻压装备上的应用提供技术积累。

液压机双驱伺服系统滑模变结构控制研究

为了提高液压机双驱伺服系统的控制精度,设计了一种基于位置与速度传感器反馈的协同策略,并设计了滑模变结构模糊控制器。研究结果表明:在不同转速间速率转变时通过三角函数形式完成柔性的过渡过程,满足转速的设计条件。滑块在运行过程中可迅速完成合模与回程的运动。进行加载处理时则以低速状态运行,获得理想的加载精度。该研究有助于提高液压机的控制精度,为后续的参数设计奠定一定的理论基础。

V弯试验设备的自动化改造及效率提升

V弯试验是评估镀锌板性能的重要方法,但传统设备依靠人工操作,效率低且存在安全隐患。因此,文章提出一种V弯试验设备的自动化改造方案,通过集成机械手、优化夹具设计、升级控制系统等,实现装夹、弯曲、压平等全流程自动化。结果显示,改造后的设备单件效率提升30%~50%,角度重复精度改善64%~66%,在提质增效方面效果显著。

SimulationX及硬件在环仿真在伺服压力机设计和研究中的应用

锻压装备水平是衡量一个国家装备制造业水平高低的重要指标,具有复合性、高效率、高精度、高柔性和低噪环保等特点的伺服控制精密压力机是锻压设备的发展方向。针对新型精密伺服锻压设备存在的非线性、电动机精确同步与控制等瓶颈问题,在分析该类压力机工作原理并进行运动反求的基础上,利用机电控多学科领域知识集成,在多领域统一建模软件SimulationX中构建压力机仿真模型,分析机械结构的合理性及精度可靠性并寻求非线性控制策略,结合Beckhoff控制器搭建基于过程控制对象链接与嵌入(Object linking and embedding(OLE)for process control,OPC)通信协议的硬件在环仿真平台,验证控制策略的可行性,解决了同步问题;并将该控制方案运用在双点伺服压力机上进行重复停止精度试验,实现重复停止精度在±10μm以内。研究表明,SimulationX及硬件在环仿真应用在伺服压力机设计中是可行的。