共查询到20条相似文献,搜索用时 281 毫秒
1.
This paper presents an improved practical controller for enhancing precision motion performance. For practical use, high motion control performance and ease of controller design are desired. A nominal characteristic trajectory following control (NCTF control) has been studied to satisfy the desired response. The NCTF controller consists of a nominal characteristic trajectory (NCT) which is the reference motion of control system and a compensator which makes the motion of the controlled object to follow the NCT. The NCT is easily determined from experimental open-loop time responses of the mechanism. The controller parameters can be also determined easily, without any given model parameters. In the present paper, the Continuous Motion NCTF controller for high continuous motion performance is improved in order to enhance the following characteristic of the object motion on NCT and improve the positioning and tracking accuracies of the system. The improved Continuous Motion NCTF controller (referred to as Acceleration Reference-Continuous Motion NCTF controller (AR-CM NCTF controller)) provides the advantages such as the high overshoot reduction characteristics and the low sensitivity disturbance. The AR-CM NCTF controller includes the structure of the Continuous Motion NCTF controller and acceleration reference for the object motion as the additional controller elements. The design procedure of the AR-CM NCTF controller remains easy and practical. In order to confirm the advantages, the AR-CM NCTF controller was examined in positioning and tracking motion performances using the non-contact mechanism. The experimental results prove that the AR-CM NCTF controller achieves the better positioning and tracking performances than the Continuous Motion NCTF controller. 相似文献
2.
The present paper describes a practical control method for a precision motion system and the performance thereof. For practical use, high motion control performance and ease of design and controller adjustment are desired. A nominal characteristic trajectory following control (NCTF control) has been investigated to realize high performance and ease of application of point-to-point (PTP) positioning. The controller comprising a nominal characteristic trajectory (NCT) and a PI compensator is free from exact modeling and parameter identification. In the present paper, the NCTF control is modified in order to improve the control performance of continuous motions such as tracking and contouring motions. The NCTF controller for continuous motion (referred to as Continuous Motion NCTF controller) has a structure that is almost identical to the conventional NCTF controller and is designed using the same design procedure. The Continuous Motion NCTF controller is applied to ball screw mechanisms, and its motion control performance is evaluated from the experimental tracking, contouring, and positioning control results. The experimental results prove that the Continuous Motion NCTF controller achieves the same positioning performance as the conventional NCTF controller, and generally achieves better continuous motion control performances than PI-D or conventional NCTF controllers. In 0.25 Hz and 100-nm radius circular motion, the experimental tracking errors for Continuous Motion NCTF were smaller than 10 nm. 相似文献
3.
In this study, a nominal characteristic trajectory following (NCTF) controller for point-to-point (PTP) positioning systems is introduced and its performance is evaluated. The NCTF controller consists of a nominal characteristic trajectory (NCT) and a compensator. The objective of the NCTF controller is to make the object motion follow the NCT and end at its origin. Therefore, the NCT is used as an intended object motion and the compensator is used to make the motion of the controlled object follow the NCT. The NCTF controller is designed based on a simple open-loop experiment of the object and no information except the NCT is necessary for controller design. The effectiveness of the NCTF controller is evaluated and discussed through simulations and experiments using an experimental rotary positioning system. The effect of the design parameters on the robustness of the NCTF controller to inertia and friction variations is evaluated and the influence of saturation on the positioning performance is examined. Moreover, the effects of the saturation on the positioning performance and robustness are compared with those of conventional PID ones. It is proved that the NCTF controller is much more accurate and robust to inertia and friction variations than the PID controllers, even if the saturation occurs. 相似文献
4.
This paper describes the practical control of precision positioning mechanisms with friction. In a controller design, the microdynamic characteristic of these mechanisms is taken into account. First, the behavior of an experimental mechanism immediately before stopping is examined experimentally and its characteristics, namely, the micro- and macrodynamic ones are modeled. Next, a practical control method is proposed for the mechanism. The controller is designed based on the nominal characteristic trajectory following (NCTF) controller design procedure. It consists of a nominal characteristic trajectory (NCT) and a PI compensator. The NCT is determined using an open-loop time response of the mechanism and is represented on a phase plane. The compensator is used to make the mechanism motion follow the NCT and to stop the motion at the origin of the phase plane. Although the compensator is designed based on the microdynamic characteristic, it is useful in a wide working range. The positioning performance of the system with the proposed controller is examined in comparison with those of the system with conventional PID controllers. These results prove that the system with the proposed controller has a better positioning performance than those with conventional PID controllers and its positioning resolution is higher than 50 nm. 相似文献
5.
Pneumatic piston–cylinder actuators are commonly used in industry for a variety of automation and robotics applications. In order to suppress leakage, these actuators comprise seal rings which unfortunately introduce friction and affect the positioning accuracy and output force. This article investigates vibrations of the seal generated by integrated piezo actuators to reduce friction force. For this, two piezoelectric stacks are integrated in the cylinder and used to excite vibration modes. This concept was studied in a compact cylinder pneumatic actuator with a bore diameter of 5 mm and a stroke of 10 mm. Dry friction measurement shows a 52% reduction from the original friction force at a driving frequency of 18.29 kHz and vibration amplitude of 0.05 μm. In the wet friction experiments, the friction force can be reduced by 54% from the original wet friction with vibrations at amplitude of 0.04 μm. 相似文献
6.
Kyoung Kwan Ahn Tu Diep Cong Thanh Young Kong Ahn 《Journal of Mechanical Science and Technology》2005,19(3):778-791
A novel pneumatic artificial muscle actuator (PAM actuator), which has achieved increased popularity to provide the advantages
such as high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available
and cheap power source, inherent safety and mobility assistance to humans performing tasks, has been regarded during the recent
decades as an interesting alternative to hydraulic and electric actuators However, some limitations still exist, such as the
air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause
the oscillatory motion Then it is not easy to realize the performance of transient response of pneumatic artificial muscle
manipulator (PAM manipulator) due to the changes in the external inertia load with high speed In order to realize satisfactory
control performance, a variable damper — Magneto-Rheological Brake (MRB), is equipped to the joint of the manipulator Superb
mixture of conventional PID controller and a phase plane switching control method brings us a novel controller This proposed
controller is appropriate for a kind of plants with nonhnearity, uncertainties and disturbances. The experiments were carried
out in practical PAM manipulator and the effectiveness, of the proposed control algorithm was demonstrated through experiments,
which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase
plane switching control method and without regard for the changes of external inertia loads 相似文献
7.
STUDY ON THE CONTROL OF SINGLE PNEUMATIC MUSCLE ACTUATOR 总被引:1,自引:0,他引:1
Fan WeiSchool of Mechanics andVehicle Engineering Beijing Institute of Technology Beijing ChinaPeng Guangzheng Chai SenchunSchool of Information Technology Beijing Institute of Technology Beijing ChinaNing RuxinSchool of Mechanics andVehicle Engineering Beijing Institute of Technology Beijing China 《机械工程学报(英文版)》2003,16(4):428-432
The control of single pneumatic muscle actuator is studied, as one basic part of research onthe parellel-robot arthrosis actuated by pneumatic muscle actuators. Experiments show that aself-modified fuzzy-PID controller is obviously effective for its position servo and a simple PID con-troller is good for its force track. 相似文献
8.
Pneumatic actuating device with nanopositioning ability utilizing PZT impact force coupled with differential pressure 总被引:3,自引:0,他引:3
This paper reports a new actuating method using piezoelectric (PZT) impact force coupled with differential pressure for the pneumatic positioning device. Fundamental experiments show that the sliding table can be actuated to move with precise step motions in both the forward and backward directions based on the proposed method. A two degree-of-freedom (DOF) analytic model is established and verified for expressing the impact actuation. Furthermore, a pulse width, which is equal to the period of second-mode vibration of the actuating device, is experimentally examined for the actuation of PZT actuator. Finally, position control based on a hybrid controller is implemented. The experimental result shows that the sliding table is successfully positioned from the reference origin to the target position of 4 mm in 0.924 s with the positioning accuracy of 5 μm due to the actuation of the pneumatic cylinder, and that the final positioning accuracy of 10 nm is obtained by the actuation of PZT impact force coupled with differential pressure. The total control time is 2.683 s. It is shown that the proposed method is capable of significantly improving the positioning performance of the pneumatic actuating device. It is expected that the proposed method will be widely applied in the precision industry using pneumatic cylinders. 相似文献
9.
With the development of precision manufacturing technologies, the importance of precision positioning devices is increasing.
Conventional actuators, dual stage or mechanically contacting type, have limitation in coping with performance demands. As
a possible solution, magnetic suspension technology was studied. Such a contact-free system has advantages in terms of high
accuracy, low production cost and easy adaptability to high precision manufacturing processes. This paper deals with magnetically
suspended multi-degrees of freedom actuator which can realize large linear motion. In this paper, the operating principle
is explained with the magnetic force analysis, and the equations of motion are derived. Experimental results of the implemented
system are also given. 相似文献
10.
Model reference adaptive control for a piezo-positioning system 总被引:1,自引:0,他引:1
Piezoelectric (PZT) actuators having the characteristic of infinitely small displacement resolution are popularly applied as actuators in precision positioning systems. Due to its nonlinear hysteresis effect, the tracking control accuracy of the precision positioning system is difficultly achieved. Hence, it is desirable to take hysteresis effect into consideration for improving the trajectory tracking performance. In this paper, a model reference adaptive control scheme based on hyperstability theory is developed for a moving stage system driven by a PZT actuator. It is worth emphasizing that the controller can be constructed without a nonlinear hysteresis dynamic equation to compensate the hysteresis effect. According to simulation results, the tracking error was only nanometer order. Through experimental examinations, the tracking performance was obtained as precision as ten nanometers order which is the resolution limitation of the measurement system. The effectiveness of the proposed adaptive control scheme was validated. 相似文献
11.
12.
Precision position control using combined piezo-VCM actuators 总被引:2,自引:0,他引:2
This paper presents the control performance of a high-precision positioning table using the hybrid actuators composed of the piezoelectric (PZT) actuators and voice-coil motors (VCMs). The combined piezo-VCM actuator features two main characteristics, i.e., a large operation range due to the long stroke of VCM, and a high precision and heavy load positioning ability due to the actuation of PZT impact force. In this paper, a one-degree-of-freedom (1-DOF) experimental setup was configured to examine the control performance and the parametric identification for the VCM was performed based on the recursive-least-square (RLS) method. The control performance was effectively demonstrated by using a switching controller configured by an integral variable structure controller (IVSC) for the VCM to conduct rough position control and an impact force controller (IFC) for the PZT actuator to conduct fine position control. The experimental results showed that the positioning table having mass 881 g was successfully positioned within the positioning accuracy of 10 nm by both the forward and backward positioning processes. In the forward control, it totally took 1.253 s for the sliding table to reach the target position of 450 μm; in the backward control, it took 1.387 s for the sliding table moving from the position of 450 μm to the target position of 200 μm. 相似文献
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16.
In this paper, positioning control of a rodless cylinder in pneumatic servo systems with actuator saturation is investigated via an active disturbance rejection control. A linear extended state observer is designed to estimate and compensate strong friction force and other nonlinearities in the pneumatic rodless cylinder system. An actuator saturation linear feedback control law is developed to further improve the control performance. Furthermore, a linear matrix inequality-based optimization algorithm is employed to estimate a strictly invariance set for the closed-loop system. Experiment results with response time 0.5 s and accuracy 0.005 mm for a 200 mm step signal demonstrate the effectiveness of the proposed control strategy. 相似文献
17.
设计制作了一种采用双晶片压电陶瓷结构的棒板结合式压电驱动器.和瓷片分别粘接在青铜定子的上下两侧.定子上的金属圆柱体被用来放大振动的横向位移,并对金属棒状的转子进行激振,使其旋转.利用有限元分析(FEA)对定子进行了分析,发现在同样的驱动模式下,与传统的单片陶瓷片驱动器相比,该驱动器可以提供更多的横向和纵向的振动位移,大约提高25%左右.这种新结构也可避免不同振动模式之间的模态耦合现象,并产生理想的振动模态,以提高驱动器的运行稳定性.实验表明,驱动器在25 Vo-p低电压下可以提供512r/rain的转速,而单片陶瓷驱动器在该电压下不能工作.这种压电驱动器可以经过优化和调整来满足不同的实际应用,如精确定位仪器,生物工程和光聚焦系统等. 相似文献
18.
Samir Mekid 《Journal of Mechanical Science and Technology》2009,23(11):2873-2884
Some key aspects in the design of actuators for ultra precision systems will require particular attention as actuators have
to comply with ultra precision positioning and related tight specifications. The actuation is an important sub-group within
the overall system to be designed. Any design failure in this sub-group will degrade drastically the machine performance.
An interface analysis with immediate surrounding sub-groups is important to secure better generation of motion. In this paper,
a design procedure for an actuator dedicated to generate high precision motion is presented with a discussion of some important
aspects encountered when designing a friction drive. The procedure encompasses design concepts, axis stiffness, control, system
dynamics, and, error compensation using a dedicated control strategy compensating for errors. A case study is discussed. 相似文献
19.
School of Mechanical and Automotive Engineering, University of Ulsan, San 29, Muger2-dong, Nam-gu, Uhan 680-749, Korea The
development of a fast, accuiate, and inexpensive position-controlled pneumatic actuator that may be applied to various practical
positioning applications with various external loads is described in this paper A novel modified pulse-width modulation (MPWM)
valve pulsing algorithm allows on/off solenoid valves to be used in place of costly servo valves A comparison between the
system response of the standardPWM technique and that of the modified PWM technique shows that the performance of the proposed technique was significantly increased
A state-feedback controller with position, velocity and acceleration feedback was successfully implemented as a continuous
controllei A switching algorithm foi control parameters using a learning vector quantization neural network (LVQNN) has newly
proposed, which classifies the external load of the pneumatic actuator The effectiveness of this proposed control algorithm
with smooth switching control has been demonstrated thiough experiments with various external loads 相似文献
20.
Jakub Emanuel Takosoglu Ryszard Filip Dindorf Pawel Andrzej Laski 《The International Journal of Advanced Manufacturing Technology》2009,40(3-4):349-361
The results of simulation and experimental tests conducted for pneumatic servo-drive with FLC (fuzzy logic controller) are presented. For positioning control and teaching/play-back control of pneumatic servo-drive, a fuzzy PD (proportional-derivative) controller was designed and constructed by means of xPC Target software of Matlab-Simulink package for rapid prototyping and hardware-in-the-loop simulation. The non-linear simulation model of pneumatic servo-drive was constructed and used to tune fuzzy PD controller by means of Fuzzy Logic Toolbox of Matlab-Simulink package. The fuzzy logic PD controller enables precise positioning of pneumatic servo-drive with the precision specified for industrial manipulators. A lot of simulation and experimental tests were carried on pneumatic servo-drive with fuzzy controller which was used for its transpose and follow-up control. The designed fuzzy system is efficient, stable, and resistant to disturbances and can be applied in any configurations of pneumatic servo-drive without the necessity to tune the regulator, apply signal filtration, or additional operations in track control or restrict the signals generated. Pneumatic servo-drives with teaching/playback control system have considerable practical significance, especially in the control of manipulating machines, manipulators, and industrial robots as well as rehabilitation and physiotherapy manipulators. 相似文献