共查询到17条相似文献，搜索用时 187 毫秒
1.
A dynamic velocity feed-forward compensation control (DVFCC) approach with RBF neural network (RBF-NN) dynamic model identification was presented for the adaptive trajectory tracking of industrial robots.The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model.The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accuracy.The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can convert torque signal into velocity in the standard industrial controller.Then,the need for a torque control interface was avoided in the real-time dynamic control of industrial robot.The simulations and experiments were carried out on a gas cutting manipulator.The results show that the proposed control approach can reduce steady-state error,suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space,especially under highspeed condition. 相似文献
2.
A generalized controller based on stability theory of singularly perturbed systems is proposed, to deal with the problem of bounded actuator inputs in robot trajectory tracking control. The saturation function with error-gain matrix is applied in the torque control law, which ensures the upper bound of torque inputs in any given limited range. Through appropriately setting the entries of the error-gain matrix, the tracking performance can be improved. Moreover, a pseudo signal is generated from a linear filter to substitute for the actual velocity error, eliminating the need for velocity measurements. Finally, to verify the effectiveness of the generalized controller, a new saturated controller with error-gain-contained arc tangent function is designed. Comparison experiments show that the proposed controller can strictly guarantee the bound of the torque inputs in situations with non-zero initial tracking errors, and gives a better tracking result than other controllers. 相似文献
3.
The DSC （direct self control） of speed regulation technology was applied to drive a motor running at a certain overloading ratio in intermittent working conditions. To control motor temperatures rising effectively, a finite element method with an iterative approach was applied to simulate real working conditions and analyze the temperature rising of the inner part of the motor. Application of DSC speed regulation realizes the invariable torque output quickly and avoids the peak current at the start state in favor of the motor temperature decreasing. Based on an analysis with the finite limit method, some effective measures were taken to improve the ability of the motor to expel heat. The overload ability of the motor was improved and the stable motor temperature rising was obtained, fulfilling the demands of electrical screw presses. 相似文献
4.
The suboptimal reliable guaranteed cost control （RGCC） with multi-criterion constraints is investigated for a class of uncertain continuous-time systems with sensor faults. A fauk model in sensors, which considers outage or partial degradation of sensors, is adopted. The influence of the disturbance on the quadratic stability of the closed-loop systems is analyzed. The reliable state-feedback controller is developed by a linear matrix inequalities （LMIs） approach, to minimize the upper bound of a quadratic cost fimction under the conditions that all the closed-loop poles be placed in a specified disk, and that the prescribed level of H∞ disturbance attenuation and the upper bound constraints of control inputs＇ magnitudes be guaranteed. Thus, with the above muki-criterion constraints, the resulting closed-loop system can provide satisfactory stability, transient property, a disturbance rejection level and minimized quadratic cost performance despite possible sensor faults. 相似文献
5.
Xue-ping LI Wei-qiu ZHU Zu-guang YING 《浙江大学学报(A卷英文版)》2008,9(3):330-337
An optimization method for time-delayed feedback control of partially observable linear building structures subjected to seismic excitation is proposed. A time-delayed control problem of partially observable linear building structure under horizontal ground acceleration excitation is formulated and converted into that of completely observable linear structure by using separation principle. The time-delayed control forces are approximately expressed in terms of control forces without time delay. The control system is then governed by Itoe stochastic differential equations for the conditional means of system states and then transformed into those for the conditional means of modal energies by using the stochastic averaging method for quasi-Hamiltonian systems. The control law is assumed to be modal velocity feedback control with time delay and the unknown control gains are determined by the modal performance indices. A three-storey building structure is taken as example to illustrate the proposal method and the numerical results are confirmed by using Monte Carlo simulation. 相似文献
6.
In order to deal with torque pulsation problem caused by traditional control method for brushless DC （BLDC） motor and to achieve high precision and good stability, a novel control strategy is proposed. Compared with the traditional control scheme, by using phase voltage as a control objective and making waveform of phase current approximately quasi-sinusoidal, torque ripple of BLDC motor is reduced from the original 14% to 3.4%, while toque is increased by 3.8%. Furthermore, by detecting zero-crossings of back electromotive force （BEMF） with non-conducting phases, sensorless control is realized. The new control strategy is simple. It can minimize torque ripple, increase torque, and realize sensorless control for BLDC motor. Simulation and experiments show good performance of BLDC motor by using the new control method. 相似文献
7.
We investigated wind-induced vibration control of long-span power transmission towers based on a case study of the Jingdongnan-Nanyang-Jingmen 1 000 kV transmission line project in P. R. China. The height of the cup tower is 181 m with a ground elevation of 47 m, which makes it a super flexible and wind-sensitive structure. Therefore, we should analyze the wind- resistant capacity of the system. We simulated applicable transverse fluctuating wind velocity field, developed a lead-rubber damper （LRD） for controlling wind-induced vibration of long-span transmission towers, deduced LRD calculation model parameter, and researched the best layout scheme and installation method of LRD. To calculate the wind-induced response of tower-line coupling system in seven layout schemes, we used the time history analysis method, and obtained the efficiencies of wind-induced vibration control. LRD deformation research proved that the damp of all LRDs was efficient under the designed wind velocity when they were laid along the edge of tower heads. We studied the controlling efficiency resulting fTom only applying stiffness to the tower polos where the dampers used to be laid under the designed wind velocity. The results show that the controlling efficiency was not ideal when the stiffness is increased on the poles only. Therefore, LRD should conlxibute to both the stiffness and damp of a structure to effectively reduce the dynamic response of a tower-line coupling system under strong winds. We also discussed the controlling efficiency of LRD under static winds. The results show that there was little difference between displacements derived by the finite clement time history method and those obtained by static wind method conducted by a design institute. This means the simulation on space relevant wind velocity field was accurate and reasonable. 相似文献
8.
Modeling and analysis of wet clutch engagement characteristics 总被引：1，自引：0，他引：1
A mathematical model was developed to analyze the characteristics of the wet clutch during engagement. The lubricant squeeze action was simulated with Patir and Cheng average flow model in which the permeability of friction material is taken into account, and the asperity load is calculated according to the Greenwood and Tripp approach. In this model, effects of friction material permeability, applied load and driving velocity on the engagement characteristics of the wet clutch were studied. The results show that friction material with high permeability reduces the film thickness rapidly and increases the torque peak; the applied load increases the asperity contact pressure and the friction torque, and reduces the engagement time; the driving velocity mainly increases the engagement time. The theoretical torque and relative velocity curves agree qualitatively with the experimental ones, which verifies the wet clutch engagement model. 相似文献
9.
Voltage source converter high-voltage direct current （VSC-HVDC） is a new power transmission technology pref- erable in small or medium power transmission. In this paper we discuss a new control system based on space vector modulation （SVM） without any voltage line sensors. Using direct power control （DPC） SVM and a new double synchronous reference frame phase-locked loop （DSRF-PLL） approach, the control system is resistant to the majority of line voltage disturbances. Also, the system response has accelerated by using a feed forward power decoupled loop. The operation of this control strategy was verified in a SIMULINK/MATLAB simulation environment. To validate this control system, a 5 kV.A prototype system was constructed. Compared to the original controllers, the current total harmonic distortion （THD）, the active and reactive deviations and the DC voltage overshoot were lowered by 2.5%, 6.2% and 8%, respectively. The rectifier power factor in the worst condition was 0.93 and the DC voltage settling time was 0.2 s. 相似文献
10.
Experimental Studies on High-Frequency Performance of the Inverse Control Magneto-Rheological Damper
Severe vibration of underground structures may be induced under blast loads. According to the characteristics of the explosion-induced ground shock wave, a new-type damper, inverse control magneto-rheological(MR) damper was designed to control the vibration. The high-frequency performance test of the MR damper was carried out on the small shaking table. It is shown that the performance can be modeled by use of the modified Bouc-Wen model, and the parameters of the model keep stable in the ranqe of 15-50 Hz. 相似文献
11.
该文基于陀螺对章动和进动现象从理论与实验两个角度进行了详细的研究。主要研究了陀螺质心的角位移、自转周期、进动角速度与周期,以及章动角随时间变化的规律,并给出了扭转陀螺系统运动模型。研究结果表明,陀螺的运动分为3个阶段:触发阶段、衰减阶段和反向阶段。陀螺在衰减阶段存在一定时间的稳态运动,此时陀螺的章动角几乎不变,进动轨迹为准圆周运动。进动半径越大时,陀螺进动角速度的实验值与理论值的偏差增大;陀螺的自旋周期随时间分段线性变化。该研究成果为陀螺在航空航天导航系统的应用提供了一定的参考。 相似文献
12.
分析行星轮系的运动特征,介绍求解行星轮相对于行星架的相对角速度、相对于机架的绝对角速度和行星架转动的牵连角速度的方法,从而解决行星轮系运动学中的关键问题。 相似文献
13.
为了解决无人机在无GPS或GPS信号较弱情况下的稳定悬停问题,并考虑到成本与板载资源限制,将通过小型激光雷达获得的距离信息分别与通过单摄像头获得的视觉信息,以及通过IMU（惯性测量单元）获得的惯性信息利用互补滤波算法进行融合,以实现对四旋翼飞行器姿态与水平速度的运动估计。采用基于串级PID的多闭环控制策略,实现对四旋翼飞行器水平与垂直方向的控制。实验结果表明,所设计的基于光流和小型激光雷达的四旋翼飞行器控制策略与传统利用光流和超声波测距传感器方案相比,控制精度提高了10%左右,能够以最大±2°的姿态角误差,以及最大2.3cm/s的水平速度误差实现定点悬停功能。 相似文献
14.
A stochastic optimal control strategy for partially observable nonlinear quasi Hamiltonian systems is proposed.The optimal control forces consist of two parts. The first part is determined by the conditions under which the stochastic optimal control problem of a partially observable nonlinear system is converted into that of a completely observable linear system. The second part is determined by solving the dynamical programming equation derived by applying the stochastic averaging method and stochastic dynamical programming principle to the completely observable linear control system. The response of the optimally controlled quasi Hamiltonian system is predicted by solving the averaged Fokker-Planck-Kolmogorov equation associated with the optimally controlled completely observable linear system and solving the Riccati equation for the estimated error of system states. An example is given to illustrate the procedure and effectiveness of the proposed control strategy. 相似文献
15.
Influence of water saturation on propagation of elastic waves in transversely isotropic nearly saturated soil 总被引：1，自引：0，他引：1
INTRODUCTIONIthaslongbeenrecognizedthatcompression alwavespropagationinsaturatedsoilsisstronglyaffectedbythewaterfillingtheintersticesofthesoilgrains.HardinandRichart(1 963 )appliedthetwo phasetheoryofBiot(1 956)andstudiedtheinfluenceoftheconfiningpressur… 相似文献
16.
阐述一种获取＂动力硬化＂的一般程式。基于凯恩方程导出做大范围运动任意柔体的运动方程。用几何非线性应变一位移关系和角速度的非线性表达式正确实现线性化，一般情况下可自然获取＂动力硬化＂项。休斯敦方法中偏速度和偏角速度阵列的概念和推导拓宽到柔体，并做为分析的基础。通过用于梁和板模型数值计算的结果证实了所述程式是普遍有效的。 相似文献
17.
On stochastic optimal control of partially observable nonlinear quasi Hamiltonian systems 总被引：1，自引：0，他引：1
INTRODUCTION Since many actual control systems such asthose in structural engineering are subjected torandom excitations and the system states are esti-mated from measurements with random noise,stochastic optimal control of partially observablesystems is a research subject of much significance.One basic approach to this problem is to convert itinto the stochastic optimal control of completelyobservable systems using separation theorem(Wonham, 1968; Fleming and Rishel, 1975; Ben-so… 相似文献