Surface Texture Improvement in the Turning Process Via Application of a Magnetostrictively Actuated Tool Holder

1998 ◽  
Vol 120 (2) ◽  
pp. 193-199 ◽  
Author(s):  
D. Liu ◽  
J. W. Sutherland ◽  
K. S. Moon ◽  
T. J. Sturos ◽  
A. R. Kashani
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Dynamic Response ◽  
Vibration Control ◽  
Surface Texture ◽  
Turning Process ◽  
Tool Holder ◽  
Rate Feedback ◽  
Control Scheme ◽  
Surface Profiles

An active vibration control system for a turning process is presented. The system employs a magnetostrictive actuator and a rate feedback control scheme to suppress the vibration caused by random excitation in the turning process. A specially designed tool holder is developed to implement the actuation and the control scheme effectively. A model which accounts for both the dynamic response of the cutting process and the control system is described. The effectiveness of the vibration control system is studied via simulation and a series of experiments. A disturbance force is applied to the system by a shaker and the dynamic response of the system is observed. The experimental data shows that the rate feedback control scheme adds additional damping to the system and reduces the vibration. A complete set of 24 factorial design cutting experiments were also conducted using the tool holder and experimentally obtained surface profiles were compared to surface profiles obtained without the vibration control. It is shown that the system can improve the surface texture generated by the turning process.

Stability analysis in machining process by using adaptive closed-loop feedback control system in turning process

2020 ◽  
pp. 107754632095261
Author(s):  
Kashfull Orra ◽  
Sounak K Choudhury
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Closed Loop ◽  
Machining Process ◽  
Feedback Control System ◽  
Turning Process ◽  
Tool Vibration ◽  
Loop Feedback ◽  
Closed Loop Feedback ◽  
The Stability

The study presents model-based mechanism of nonlinear cutting tool vibration in turning process and the strategy of improving cutting process stability by suppressing machine tool vibration. The approach used is based on the closed-loop feedback control system with the help of electro–magneto–rheological damper. A machine tool vibration signal generated by an accelerometer is fed back to the coil of a damper after suitable amplification. The damper, attached under the tool holder, generates counter forces to suppress the vibration after being excited by the signal in terms of current. The study also discusses the use of transfer function approach for the development of a mathematical model and adaptively controlling the process dynamics of the turning process. The purpose of developing such mechanism is to stabilize the machining process with respect to the dynamic uncut chip thickness responsible for the type-II regenerative effect. The state-space model used in this study successfully checked the adequacy of the model through controllability and observability matrices. The eigenvalue and eigenvector have confirmed the stability of the system more accurately. The characteristic of the stability lobe chart is discussed for the present model-based mechanism.

Operator-Based Robust Nonlinear Control Design of a Robot Arm with Micro-Hand

2016 ◽  
Vol 28 (4) ◽  
pp. 568-578 ◽  
Author(s):  
Zhengxiang Ma ◽  
◽  
Aihui Wang ◽  
Tiejun Chen ◽  
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Nonlinear Control ◽  
Angular Position ◽  
Control Design ◽  
Robot Arm ◽  
Robust Nonlinear Control ◽  
Precise Position ◽  
Control Scheme ◽  
Loop Feedback

[abstFig src='/00280004/14.jpg' width='300' text='Robot arm with micro-hand system' ] This work focuses on a robust nonlinear control design of a robot arm with micro-hand (RAMH) by using operator-based robust right coprime factorization (RRCF) approach. In the proposed control system, we can control the endpoint position of robot arm and obtain the desired force of micro-hand to perform a task, and a miniature pneumatic curling soft (MPCS) actuator which can generate bidirectional curling motions in different positive and negative pressures is used to develop the fingers of micro-hand. In detail, to control successively the precise position of robot arm and the desired force of three fingers according to the external environment or task involved, this paper proposes a double-loop feedback control architecture using operator-based RRCF approach. First, the inner-loop feedback control scheme is designed to control the angular position of the robot arm, the operator controllers and the tracking controller are designed, and the robust stability and tracking conditions are derived. Second, the complex stable inner-loop and micro-hand with three fingers are viewed as two right factorizations separately, a robust control scheme using operator-based RRCF approach is presented to control the fingers forces, and the robust tracking conditions are also discussed. Finally, the effectiveness of the proposed control system is verified by experimental and simulation results.

Nonlinear Modeling and Control of Overhead Crane Load Sway

1988 ◽  
Vol 110 (3) ◽  
pp. 266-271 ◽  
Author(s):  
Kamal A. F. Moustafa ◽  
A. M. Ebeid
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Digital Computer ◽  
Nonlinear Modeling ◽  
Overhead Crane ◽  
Nonlinear Dynamical ◽  
Modeling And Control ◽  
Control Scheme ◽  
Rate Of Decay ◽  
And Control

In this paper, we derive a nonlinear dynamical model for an overhead crane. The model takes into account simultaneous travel and transverse motions of the crane. The aim is to transport an object along a specified transport route in such a way that the swing angles are suppressed as quickly as possible. We develop an antiswing control system which adopts a feedback control to specify the crane speed at every moment. The gain matrix is chosen such that a desired rate of decay of the swing angles is obtained. The model and control scheme are simulated on a digital computer and the results prove that the feedback control works well.

Process Feedback Control of Non-Circular Turning for Camshaft Machining

1999 ◽  
Author(s):  
Zongxuan Sun ◽  
Tsu-Chin Tsao
Keyword(s):  
Feedback Control ◽  
Servo Control ◽  
Displacement Sensor ◽  
Turning Process ◽  
Spindle Rotation ◽  
Control Scheme ◽  
Precise Tool ◽  
Cam Profile ◽  
Process Feedback ◽  
Profile Errors

Abstract This paper presents a process feedback control scheme for cam profile generation by non-circular turning process. While precise tool slide motion can be generated based on real-time servo feedback control, it does not necessarily ensure accurate machined cam profiles. The effects of tool/workpiece geometry, tool wears, machine deformations, and spindle runout error can not be measured by the tool slide displacement sensor and hence are not compensated for by the servo control. A process feedback controller is designed to compensate for the repeatable profile errors from one machining cycle to another. Utilizing the fact that the desired cam profile is periodic over one spindle rotation, process feedback control is analyzed and designed in the frequency domain. Implementation of the process feedback control on a steel camshaft turning demonstrates improvement of the maximum cam profile errors from 80 microns to within 20 microns in five iterations.

Model Based Simulation of the Active Damping of a Cantilever Plate and Redistribution of Stresses

2000 ◽  
Author(s):  
Sathya V. Hanagud ◽  
Patrick J. Roberts
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Closed Loop ◽  
Active Vibration Control ◽  
High Stress ◽  
Element Simulation ◽  
Control Scheme ◽  
Acceleration Feedback ◽  
Order Of Magnitude ◽  
Active Vibration

Abstract In most structures, fatigue critical areas are associated with regions of high stresses. Sometimes, passive stiffening of structures can displace these high stress regions. Thus, for most applications, active vibration control is preferred. However, the question of whether an active vibration control scheme involving a set of actuators will reduce stresses in the whole structure or create high stress areas in the vicinity of the actuators arises. In previous works, this question has been addressed for cantilever beams which showed that the stresses are reduced by approximately the same order of magnitude as the reduction in vibrations. However, many aerospace structures are constructed of thin walled components whose response to vibration reduction can be very different than that of beams. In this paper, the stresses induced by an active vibration control system, based on the use of an offset piezoceramic stack actuator with acceleration feedback control, are investigated in a plate structure. A 3-D finite element simulation of the closed loop active vibration control system is developed and both the closed loop stresses and vibration amplitude reductions are studied.

Research on active vibration control of flexible wing based on MFC actuator

2020 ◽  
Vol 64 (1-4) ◽  
pp. 565-571
Author(s):  
Yajun Luo ◽  
Fengfan Yang ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
...  
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Torsional Vibration ◽  
Fiber Composite ◽  
Active Vibration Control ◽  
Current Control ◽  
Control Effect ◽  
Flexible Wing ◽  
Control Scheme ◽  
Active Vibration

An active vibration control scheme was proposed based on Macro Fiber Composite (MFC) actuators for the bending and torsional vibration control of large flexible lightweight wing structures. Firstly, a finite element modeling and modal analysis of a flexible wing are carried out. Further, the number, type, and location distribution of the MFC actuators bonded on the supported beam of the wing are designed. Then, the actuated characteristics of the two kinds of MFC actuators required for bending and torsional vibration controls was theoretically analyzed. The simulation model of the overall vibration control system was also finally obtained. Finally, through ANSYS simulation analysis, the vibration control effect of the current control system on the first two-order low-frequency modal response of the wing structure is given. The simulation results show that the proposed active vibration control scheme has specific feasibility and effectiveness.

Active Damping by Acceleration Feedback Control and Redistribution of Stresses in the Structure

1999 ◽  
Author(s):  
Maxime P. Bayon de Noyer ◽  
Patrick J. Roberts ◽  
Sathya V. Hanagud
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Vibration Control ◽  
Closed Loop ◽  
Driving Forces ◽  
Active Vibration Control ◽  
High Stress ◽  
Low Frequency ◽  
Acceleration Feedback ◽  
Active Vibration

Abstract In most structures, fatigue critical areas are associated with regions of high stresses. Passive stiffening of structures usually displaces these high stress regions. Thus, for most applications, active vibration control is preferred. However, the question of whether an active vibration control scheme involving a set of actuators will reduce stresses in the whole structure or create high stress areas in the vicinity of the actuators arises. In this paper, the stresses induced by an active vibration control system based on the use of an offset piezoceramic stack actuator with acceleration feedback control are investigated. Using a modal analysis of the actuator acting on a cantilever beam, a low frequency approximation of the actuator is developed in the form of a spring and two driving forces. Based on this approximation, a 3-D finite element simulation of the closed loop active vibration control system is developed and the closed loop stresses are studied.

Vibration-Isolation Characteristics of an Active Electromagnetic Force Generator and the Influence of Generator Dynamics

1990 ◽  
Vol 112 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Hong Su ◽  
S. Rakheja ◽  
T. S. Sankar
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Electromagnetic Force ◽  
Vibration Isolation ◽  
Active Vibration Control ◽  
Control Scheme ◽  
Active Vibration ◽  
Force Generator ◽  
Vibration Isolation Performance ◽  
Isolation Performance

Vibration-isolation characteristics of an active vibration control system incorporating an electromagnetic force generator (actuator) are investigated. The electromagnetic force generator is modeled as a first-order dynamical system and the influence of dynamics of the force generator on the vibration-isolation performance of the active isolator is investigated via computer simulation. It is concluded that the dynamics of the force generator affect the vibration-isolation performance significantly. An active control scheme, based upon absolute position, velocity, and relative position response variables, is proposed and investigated. In view of the adverse effects of generator dynamics, the proposed control scheme yields superior vibration isolation performance. Stability analysis of the active vibration control system is carried out to determine the limiting values of various feedback control gains.

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