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1.
Adaptive neuro-fuzzy control of a flexible manipulator   总被引:1,自引:0,他引:1  
This paper describes an adaptive neuro-fuzzy control system for controlling a flexible manipulator with variable payload. The controller proposed in this paper is comprised of a fuzzy logic controller (FLC) in the feedback configuration and two dynamic recurrent neural networks in the forward path. A dynamic recurrent identification network (RIN) is used to identify the output of the manipulator system, and a dynamic recurrent learning network (RLN) is employed to learn the weighting factor of the fuzzy logic. It is envisaged that the integration of fuzzy logic and neural network based-controller will encompass the merits of both technologies, and thus provide a robust controller for the flexible manipulator system. The fuzzy logic controller, based on fuzzy set theory, provides a means for converting a linguistic control strategy into control action and offering a high level of computation. On the other hand, the ability of a dynamic recurrent network structure to model an arbitrary dynamic nonlinear system is incorporated to approximate the unknown nonlinear input–output relationship using a dynamic back propagation learning algorithm. Simulations for determining the number of modes to describe the dynamics of the system and investigating the robustness of the control system are carried out. Results demonstrate the good performance of the proposed control system.  相似文献   

2.
《Mechatronics》2007,17(6):311-323
This article presents a new application of model-based predictive controller (MPC) for vibration suppression of a flexible one-link manipulator using piezoceramic actuators. Simulation and experimental studies were conducted to investigate the applicability of the MPC strategy to control vibration of the flexible structure having multiple inputs and multiple outputs (MIMO). The performance of the proposed technique was assessed in terms of level of vibration reduction. The results demonstrated that the proposed predictive control strategy is well suited for multivariable control of vibration suppression on flexible structures.  相似文献   

3.
Inertial vibration damping control of a flexible base manipulator   总被引:1,自引:0,他引:1  
A rigid (micro) robot mounted serially to the tip of a long flexible (macro) robot is often used to increase the reach capability, but flexibility in the macro-manipulator can make it susceptible to vibration. A rigid manipulator attached to a flexible but unactuated base was considered as an analogous problem. The interaction forces and torques acting at the base of the robot are used to damp the vibration. Appropriate control gain limits are established to ensure the inertia effects, or those directly due to accelerating the links of the rigid robot, have the greatest influence on the interactions. By commanding the link accelerations out of phase with the base velocity, vibrational energy will be removed from the system. This signal is then added to the rigid robot position controller, providing combined rigid robot position and vibration control of the base.  相似文献   

4.
A system has been constructed which adaptively corrects for an applied phase error along the length of a flexible linear array. The system utilises resistance strain gauges and electrically controlled ferrite phase shifters. Results at 9.4 GHz are presented, in the form of radiation patterns, to provide an illustration of the system performance.  相似文献   

5.
In this paper, a feedback control law is proposed for regulating the contact force exerted by a very lightweight single-link flexible manipulator when it comes into contact with a motionless object. This control law is based on a lumped-parameter model. The tracking of the desired contact force is obtained by using a feedback loop control of the coupling torque between the motor and the flexible arm. To achieve a good performance on the force control it is only necessary to measure the coupling torque at the root of the arm. Neither the contact force sensor nor the angular position sensor of the motor are used in the control method. A modified PID controller is proposed for this control law. In this work the force control problem is studied for both free and constrained motions of the flexible manipulator, and a collision detection algorithm is also described.  相似文献   

6.
Many industries require non-contact and flexible manipulation systems, such as magnetic or pneumatic devices. In this paper, we describe a one-degree-of-freedom position control of an induced-air flow surface. This device allows to convey objects on an air cushion using an original aerodynamic traction principle. A model of the system is established and the parameters are identified experimentally. A H robust controller is designed and implemented on the device in order to control the object position. Experiments with objects of various dimensions and materials are conducted and showed the robustness capabilities of the controller.  相似文献   

7.
This paper presents the design and implementation of a hybrid force/motion control scheme on a six-degrees-of-freedom robotic manipulator employing a gain-scheduled linear parameter-varying (LPV) controller. A nonlinear dynamic model of the manipulator is obtained and the unknown parameters are estimated. The manipulator is decomposed into an inner and a wrist submodel, and a practical way is proposed to investigate the coupling between them. The motion control part of the hybrid controller which is the main focus of this paper is formed by a combination of an LPV controller and a model-based inverse dynamics controller for the inner submodel and the wrist joints, respectively. A quasi-LPV model with a reduced number of scheduling parameters is derived for the inner submodel, and a polytopic LPV gain-scheduled controller is synthesized in a two-degrees-of-freedom structure including feedback and feedforward parts, which is augmented by a friction compensation term. A PD controller with a feedforward path is designed to control the interaction force. The proposed hybrid force/motion scheme is implemented on the 6-DOF CRS A465 robotic manipulator to perform a writing task. Comparison of the results with those of a hybrid force/motion controller with a plain model-based inverse dynamics motion control and the same force control shows that the proposed controller improves the position tracking performance significantly.  相似文献   

8.
The remote operations of an integrated optic Mach-Zehnder modulator via a low-birefringence fiber link using an input polarization control scheme is demonstrated. The polarization tracking scheme actively maintains the state of polarization arriving at the modulator in the state required for optimum operation of the device. As the feedback signal is determined by the overall optical throughput of the modulator, no modulation is itself required for the modulator to be set for optimum performance.<>  相似文献   

9.
布里渊散射的分布式光纤温度传感器的研究进展   总被引:4,自引:0,他引:4  
提要:基于布里渊散射的分布式光纤温度传感技术凭借着其独特的优点,在国内外引起了广泛的关注,成为了一大热点研究,本文综述了基于布里渊散射的分布式光纤温度传感技术的研究现状。在简单介绍了布里渊测温原理的基础上,针对目前布里渊散射的光纤温度传感器存在的在测量范围以及空间分辨率上的缺陷、不足,重点介绍了布里渊散射的分布式光纤温...  相似文献   

10.
A novel method is proposed and demonstrated for multiplexing fiber-optic interferometric sensors using the FMCW technique. The method uses a gas laser whose optical frequency is modulated sinusoidally by an external modulator. The use of gating and appropriate signal processing can achieve low crosstalk between sensors. Experiments on two and three sensor systems are reported. The minimum detectable signal measured is 1 mrad/sqrt{Hz}and the crosstalk factor achieved is -35 dB. The major causes of crosstalk are also analyzed.  相似文献   

11.
We report the first measurement of the polarization crosscoupling of a 900-m length of quadrupolar-wound sensing coil for the fiber optic gyroscope (FOG) using polarization maintaining photonic crystal fibers (PM-PCFs). The crosscoupling is analyzed with the Optical Coherence Domain Polarimeter (OCDP). Also the polarization extinction ratio (PER) of the PM-PCF coil is measured. For comparison, a standard panda fiber coil with nearly the same length is examined. The results show that PER of the PM-PCF coil is ~10 dB larger than the panda fiber coil, and polarization crosscoupling in the PM-PCF coil is ~10 dB less than in the panda fiber coil. Moreover, based on measurements, a 4-fold reduction in phase error is demonstrated numerically in a FOG made of the PM-PCF coil, compared to the same gyro operated with a similar coil of panda fiber. These findings have important benefits in a higher measurement precision and stability of FOG.  相似文献   

12.
This paper presents the motion control of a six degree-of-freedom tendon-based parallel manipulator, which moves a platform with high speed using seven cables. To control the motion of the platform along desired trajectories in space, nonlinear feedforward control laws in the cable length coordinates are used. Taking account of the effect of redundancy on actuation, the optimal tension distribution should be considered to the advantage of the control laws. Using a method based on the analysis of the workspace condition, tension constraints and limiting torque constraints of actuators, an analytical solution for optimum tension distribution was found and used to compute the force in each cable for compensation of dynamic errors. It is experimentally demonstrated that the proposed control laws reduce the energy consumption of the actuators and satisfy the path tracking accuracy.  相似文献   

13.
We have proposed a user extensible optical CDMA system which employs a repeated use of codes in the encoders and the decoders. In this study, we report the user-extension effect by using an array of superstructured fiber Bragg grating (SSFBG) as an encoder and a decoder through the simulations and the experiments. We performed the experiments by using 4 SSFBGs in each encoder and decoder. We have shown that the capable number of users can be increased up to 63C1?63C1?63P2 when 63 orthogonal codes are used.  相似文献   

14.
The formulation and implementation of a synchronization control scheme applicable to a robotic workcell is described. Such a workcell typically consists of a conveyor system that transports industrial workpieces, a binary camera to recognize the geometric and other characteristics of the workpiece, and a robotic manipulator that is suitably controlled to direct its end effector to achieve a synchronized rendezvous with the workpiece. Subsequent to a successful rendezvous, the robot may pick up the piece (in pick-an-place operations) or perform such other online operations as assembly, processing, or quality inspection. A methodology to ensure rapid rendezvous with accurate tracking is emphasized. Simulation and implementation results are compared and discussed  相似文献   

15.
Vibration control of linear robots using a piezoelectric actuator   总被引:3,自引:0,他引:3  
This paper presents the results of vibration control strategy for high-speed linear robots using an auxiliary piezoelectric actuator. With acceleration reaching 3 g, rapid horizontal slewing motion inevitably excites the structural resonances of the robot and generates vertical vibration forces exceeding the tolerance of the end-effector. Instead of controlling the robot vibration from the main actuators (ac servomotors with limited bandwidth), a piezoelectric actuator is deployed to provide vibration suppression at the load in the z direction. This way the robot is treated as a disturbance generator while the piezoactuator is considered as the plant. A digital servocompensator is then designed and implemented to suppress these vibration modes. Typically, attenuation is achieved for the dominant mode with 30 dB and other modes with 15 dB. Suppression of vibration up to seven modes has been implemented satisfactorily.  相似文献   

16.
17.
The performance of a fiber optic subcarrier link using an HBT as a direct photodetector and an optoelectronic up-converter in 50 GHz band has been experimentally investigated at a wavelength of 0.83 μm. From comparison with the performances of links using other MMIC-compatible photodetectors and with that of a high speed PIN-photodetector, this paper shows that the HBT-photodetector is superior to the other MMIC compatible photodetectors (MSM and HEMT). It is also shown that HBT not only has a high photodetection ability in the millimeter-wave band but also provides low conversion loss between a microwave subcarrier modulated by an optical signal and a millimeter-wave carrier. Also demonstrated are video FM-subcarrier transmission and 140 Mbps QPSK digital radio transmission using an HBT optical/RF transducer. At transducer transmission power of around -20 dBm, the HBT optical/RF transducer allows 50 GHz band radio transmission over optical fiber to achieve a weighted SNR of more than 50 dB and a data rate of 140 Mbps in indoor application  相似文献   

18.
In this work a mechatronic model was developed for a parallel Multi-Axial Simulation Table (MAST) mechanism. The dynamics of the mechanism was obtained using the principle of energy equivalence and Boltzmann–Hamel equations. In this way, the procedure to obtain the explicit dynamic equations is simplified and has the advantage of being systematic. Also, the actuators and the control were modeled and integrated to simulate and study the system’s positioning and torque.A remarkable contribution of this work is that the mechatronic model developed considers the mechanism as a disturbance to the actuators in a decoupled manner, allowing to easily evaluate alternative designs of whether the actuators, the mechanism or both. Additionally, the procedure taken has been validated with experimental data from an actual MAST prototype.  相似文献   

19.
A method for feedback control of the temperature of shape memory alloy (SMA) actuators without using dedicated temperature sensors is presented in this paper. Thermoelectric devices (TEDs) are used to simultaneously sense and control the SMA temperature by alternating between driving the TEDs via the Peltier effect and measuring the local temperature difference across the TEDs via the Seebeck effect. A low-order ARX model that estimates the SMA temperature is derived. This model is used for feedback control of the SMA temperature in lieu of an external temperature sensor. A controller is implemented, which demonstrates the performance of the estimation technique. This method will enable the production of large arrays of TED-driven SMA tendon actuators, particularly for large DOF robotic systems.  相似文献   

20.
At the present time, actuators with several degrees of freedom (Dof) are being used more and more frequently. In order to yield viable devices, it is necessary to ensure high performance, as well as keeping the cost low. This paper deals with the modeling and control of a 2Dof permanent magnet planar actuator. A prototype dedicated to theoretical conclusion validations is presented and its operation explained. A model, based on a permeance network, is introduced. The simulation results are compared to measurements obtained using a manufactured prototype. Three Hall effect sensors are then used to obtain the xy position of the moving part. From these signals, simulations of a scalar control are obtained using Matlab Simulink®.  相似文献   

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