Design and Control of a Linear Electrostrictive Motor

1999 ◽  
Author(s):  
Min Hu ◽  
Hejun Du ◽  
Shihfu Ling ◽  
Yong Li ◽  
Zhaoying Zhou
Keyword(s):  
Thrust Force ◽  
Electrical Discharge Machining ◽  
Precision Motion Control ◽  
Micro Electrical Discharge Machining ◽  
Ultra Precision ◽  
Precision Motion ◽  
P Type ◽  
And Control ◽  
High Thrust ◽  
Maximum Thrust

Abstract This paper presents a novel linear electrostrictive motor with high resolution and large stroke for ultra-precision motion control. High thrust force is obtained by taking use an electromagnetic clamping mechanism with force magnifying structure in the motor design. An operator alterable P-type iterative learning control algorithm is proposed for the digital control of the motor. A prototype of the motor, which is 60mm in diameter and 120mm in length, is designed, built and tested. Experimental results show that the prototype has a mechanical resolution of 0.02μm, less than 2μm yawing error and maximum thrust force of 30N. Applications of the motor include producing the servo feed motions required in micro electrical discharge machining (micro-EDM) system or as a precision motion device for other micro machining systems.

Study on Technology of Block Electro-Discharge Grinding with Lower Working Voltage for Fabricating Micro Electrode

2008 ◽  
Vol 375-376 ◽  
pp. 303-307
Author(s):  
Zhen Long Wang ◽  
Wei Liang Zeng ◽  
Qiang Gao
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Slenderness Ratio ◽  
Threshold Value ◽  
Micro Machining ◽  
Minimum Diameter ◽  
Micro Electrical Discharge Machining ◽  
Machining Speed ◽  
And Control ◽  
Working Efficiency

Micro electrical discharge machining (EDM) with block electro discharge grinding (BEDG), is explored and assessed as a method for developing micro electrode, for wire electro discharge grinding (WEDG) has shortcoming of low working efficiency, especially in the case of micro machining. For fabricating micro electrode by BEDG, mechanics of initial clamping errors are analyzed, the technology of electrode movement is proposed to compensate the clamping errors and control the finish size of micro electrodes. On the basis of a great deal of experiments, the effect of working voltage on machining efficiency has been found out and been analyzed theoretically, threshold value of working voltage is determined to be about 30V.As shown by result with the technology, at a high machining speed, the minimum diameter of micro electrodes reaches 3*m, its slenderness ratio is more than 5.

Integrated Optimization of Structure and Control in Ultra-Precision Motion Systems

2019 ◽  
Author(s):  
Jing Wang ◽  
Ming Zhang ◽  
Yu Zhu ◽  
Xin Li ◽  
Leijie Wang
Keyword(s):  
Complex Dynamics ◽  
System Level ◽  
Structural Topology ◽  
Worst Case ◽  
Integrated Optimization ◽  
Motion System ◽  
Material Interpolation ◽  
Ultra Precision ◽  
Precision Motion ◽  
And Control

Abstract Ever-increasing demands for precision and efficiency in ultra-precision motion systems will result in a lightweight and flexible motion system with complex dynamics. In this paper, a systematic approach is proposed where control gains, 3D structural topology and actuator configuration are integrated into optimization to derive a system-level optimal design which possesses a high vibration control performance, and still satisfies multiple design constraints. A material interpolation model with high accuracy is proposed for the integrated optimization, a simple integral equation utilizing R-functions and level-set functions is established to represent complex non-overlapping constraints of actuators. Over-actuation degrees are utilized to actively control the dominant flexible modes. Responses of residual flexible modes are restricted by increasing the coincidence of their nodal areas at actuators (sensors) locations. The objective function is the constructed worst-case vibration energy of the flexible modes. A dual-loop solving strategy combining the genetic algorithm and the modified optimal criteria method is adopted to solve the optimization problem. A fine stage in the wafer stage is designed to prove the effectiveness of the proposed method.

A Novel Compliant Actuator With Load-Dependent Variable Stiffness: Design Concept and Control

2016 ◽  
Author(s):  
Lu Lu ◽  
Jiawei Li ◽  
Cong Wang ◽  
Dan Strassberg
Keyword(s):  
Motion Control ◽  
External Load ◽  
Load Condition ◽  
Variable Stiffness ◽  
Design Concept ◽  
Inertia Force ◽  
Precision Motion Control ◽  
Precision Motion ◽  
And Control ◽  
Compliant Actuator

To develop the next generation of high-performance robots capable of working in human environments, it is required that the joint actuators have variable stiffness to achieve both precision motion control and ability of reaction under unexpectedly huge impact caused by collision with obstacles or human. Variable stiffness actuators (VSA) partially realize such objectives by employing an auxiliary input to change the joint stiffness. However, it requires prior information of external load condition. Load sensors or online load estimation techniques need to be implemented to detect sudden unexpected load for stiffness adjustment, adding complexity to the system with bandwidth issues. In this paper, we propose a new design of compliant actuator in which the stiffness automatically varies depending on the unexpected external load. A novel doubly-clamped box structure is used to connect the load inertia to the motor inertia. Specifically, the load inertia is confined inside a box clamped by two stoppers on two opposite sides with two pre-compressed springs. A secondary motor connects to the load inertia through another spring, compensating for known unbalanced forces such as gravity, Coriolis force and inertia force. It is shown that if the unexpected external load force is below the pre-compression force of the springs, the load inertia will be confined exactly within the box and the system behaves like a rigid actuator, otherwise one of the springs will be further compressed and the system behaves like a compliant actuator. Such a mechanical structure has the ability of achieving both precision motion control and automatic reaction under unexpectedly huge external impact, without the need of additional load sensing/estimation. Control algorithms for accurate position tracking under potentially huge unexpected load is developed for this new type of actuator. Simulations are conducted to verify the effectiveness of the design concept and control.

scholarly journals Iterative tuning notch filter for suppressing resonance in ultra-precision motion control

2016 ◽  
Vol 8 (11) ◽  
pp. 168781401667409 ◽  
Author(s):  
Wei Teng ◽  
Xiaolong Zhang ◽  
Yangyang Zhang ◽  
Liangliang Yang
Keyword(s):  
Motion Control ◽  
Notch Filter ◽  
Precision Motion Control ◽  
Ultra Precision ◽  
Precision Motion

Roll Vibration Analysis of Planar Aerostatic Bearings through a Distributed Spring Model

2011 ◽  
Vol 346 ◽  
pp. 332-338
Author(s):  
Wei Jiang ◽  
Wen Chuan Jia ◽  
Shan Shan Liu ◽  
Yuan Tai Hu ◽  
Hong Ping Hu
Keyword(s):  
Working Conditions ◽  
Spring Model ◽  
Aerostatic Bearing ◽  
Normal Stiffness ◽  
Ultra Precision ◽  
Aerostatic Bearings ◽  
Precision Motion ◽  
And Control ◽  
Distributed Spring Model ◽  
Stiffness Distribution

The aerostatic bearings used in guide ways in ultra precision motion stages can provide both normal stiffness and roll stiffness, which are critical to the dynamic characteristics and control of systems. The normal stiffness has been widely investigated so far, but the roll one has seldom been studied. A new method for analyzing the roll stiffness is proposed, in which the aerostatic bearing is modeled as a set of distributed springs. The stiffness distribution is obtained by using the derivate of the pressure distribution with respect to the air gap. All the distributed springs are then integrated by using the presented transformation and it leads to an equivalent spatial spring which contains both the normal stiffness and the roll stiffness. A planar aerostatic bearing is taken as an example to illustrate the procedure of the calculation. The proposed method can be used to predict the vibration characteristics of various kinds of aerostatic bearings under working conditions.

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