scholarly journals Research on Accuracy Analysis and Motion Control of Two-axis Non-magnetic Turntable Based on Ultrasonic Motor Journal

Mechanika ◽  
2020 ◽  
Vol 26 (3) ◽  
pp. 221-230
Author(s):  
Zhuo WANG ◽  
Xin-tong WANG ◽  
Tao WANG ◽  
Hong-wen MA

In the calibration process of the positioner, in order to obtain the accurate angular position information of each axis of the turntable, it is necessary to test the rotation accuracy of the turntable higher than the accuracy of the target gyroscope, in order to achieve the test and calibration of the positioner. Therefore, this paper uses the non-magnetic technology to carry out research on the pointing accuracy and motion control of the turntable. At the same time, the influence of grating installation error on precision detection is analysed. The influence of steady-state error of turntable on the motion accuracy of turntable is analysed. Finally, the influence of servo control parameters on the dynamic performance of turntable and the influence on steady-state error are analysed. The test of the corner positioning accuracy of the turntable is carried out. The positioning accuracy and motion control parameters of the two-axis precision non-magnetic turntable are obtained, and the PID adjustment is introduced to make the accuracy index of the non-magnetic turntable meet the requirements. The turntable can realize a non-magnetic working environment and can achieve the high precision required by the index under the driving of the ultrasonic motor.

2021 ◽  
Vol 16 ◽  
pp. 183-193
Author(s):  
Imran S. Sarwar

The usage of Brush-Less Direct Current (BLDC) motor has been increased in the industry especially in the field of Aerospace and electric bikes. The requirements for motion control were generated from the human eye features. The settling time and % overshoot were the desired features and design parameters. Based on desired features, values of  and ωn were found. The root-locus technique was applied to the uncompensated and compensated system, the results were not satisfactory. The % overshoot was very high, and the steady-state error was also very high. The state feedback controller was applied to the system. The % overshoot was controlled successfully but the steady-state error was still very high. To reduce the steady-state error to zero the integral control was applied. The comparison of results is presented in tabular form in the last section.


Author(s):  
Y. Munandar K. ◽  
Eka Firmansyah ◽  
Suharyanto Suharyanto

Maximum power point tracking (MPPT) algorithm seek the MPP to maximize delivered the power of a photovoltaic panel. From several MPPT algorithms, the perturb and observe (P&O) algorithm is commonly used algorithm because of its easy implementation. However, it is not the most efficient algorithm due to the perturbation step is fixed. By using the high step size, the MPP tracking became fast but there would be a high steady state error and by using the low step size, there would be less steady state error but the MPP tracking became slow. Resulting in a waste of energy in steady-state conditions when the working point passes through the MPP and poorly dynamic performance indicated when the setpoint changes due to solar irradiation changes. In this paper, a modification variable step-size of the P&O algorithm has been proposed with setting the step-size automatically at each point of work. To validate the concept of modification variable step-size, simulation using PSIM has been carried out. Compared with the conventional P&O method with fixed step-size, the proposed modified P&O method can increase tracking speed and efficiency in the system.


2011 ◽  
Vol 340 ◽  
pp. 421-428
Author(s):  
Guo Cheng Zhang ◽  
Lei Zhang ◽  
Lei Wan ◽  
Ji Qing Li

Because of nonlinear dynamic performances and uncertain working environment, precise motion control of Automatic Underwater Vehicle (AUV) has always been a problem. For the time lag and nonlinearity of AUV, a new method called Predictive S Control (PSC) based on model of Support Vector Machine (SVM) is presented. Firstly, in establishing the model of SVM, the fine property of approaching to the nonlinear model is utilized to solve the predictive problem. Then, the control parameters of S controller are optimized by constructing the error function. At last the motion control of AUV is realized. It has been proved that this method is feasible and effective. Using this method, a good control result is obtained in the simulation.


2022 ◽  
Vol 9 ◽  
Author(s):  
Fuyun Wu ◽  
Zhuang Sun ◽  
Weiji Xu ◽  
Zhizhou Li ◽  
Jianguo Lyu

Under weak grid conditions, the variation of the grid impedance will affect the steady-state and dynamic performance of the LCL-filtered grid-connected inverter and even make the inverter unstable. To ensure the system stability and further improve the dynamic performance in a weak grid, a control parameter design method with multi-constrains considering the system bandwidth for the current controller and active damping is proposed in this paper. First, based on the current controller and active damping with only grid current feedback, the effects of control parameters and grid impedance on the LCL resonant suppression and the performance of the inverter are analyzed. Moreover, the parameter constraints of the controllers are derived considering the grid impedance, including stability, resonance suppression, and margin constraints. Furthermore, as the system bandwidth affects the dynamic performance of the inverter, combined with the obtained multi-constraints, the optimal control parameters are determined by achieving the maximum bandwidth of the system against the impedance variation. Compared with other two methods, when the proposed method is applied, the system can operate with a better dynamic and steady-state performance. Finally, experiments are performed on a 2 kW three-phase grid-connected inverter in the weak grid, which verify the effectiveness of the parameter design method proposed in this paper.


Author(s):  
Yohichi Nakao ◽  
Naoya Asaoka

A precise spindle is essential to achieve precision machining, such as diamond turning. A fluid driven spindle supported by hydrostatic bearings was thus designed and tested. A feature of the spindle is that several flow channels are designed in its rotor so that driving torque can be generated by supplying pressurized flow into the channels. Rotational speed of the spindle can be controlled by the flow rate. In addition, the rotational direction of the spindle can be controlled by switching supply ports. Thus angular position control of the spindle is achieved by designing appropriate feedback controller. In the present paper, mathematical model of the spindle was thus derived in order for designing an angular position control system. Then spindle characteristics calculated by the mathematical model were compared with experimental results. Furthermore, the angular position control system that has a disturbance observer in its feedback loop was designed based on the mathematical model. The performance of the designed control system was experimentally investigated through the step response. Experimental results verified that the designed controller minimizes the steady state error of angular position of the spindle. Consequently, the steady state error was comparable with the resolution of the rotary encoder, 0.018 degree. In particular, the experimental results indicated that the disturbance observer effectively reduced the influence of various load torque on the angular position of the spindle.


2018 ◽  
Vol 138 (5) ◽  
pp. 498-505 ◽  
Author(s):  
Toyoaki Tanikawa ◽  
Tomohiro Henmi ◽  
Akira Inoue ◽  
Akira Yanou ◽  
Shinich Yoshinaga
Keyword(s):  

Author(s):  
Xiaolei Shi ◽  
Yipeng Lan ◽  
Yunpeng Sun ◽  
Cheng Lei

This paper presents a sliding mode observer (SMO) with new reaching law (NRL) for observing the real-time linear speed of a controllable excitation linear synchronous motor (CELSM). For the purpose of balancing the dilemma between the rapidity requirement of dynamic performance and the chattering reduction on sliding mode surface, the proposed SMO with NRL optimizes the reaching way of the conventional constant rate reaching law (CRRL) to the sliding mode surface by connecting the reaching process with system states and the sliding mode surface. The NRL is based on sigmoid function and power function, with proper options of exponential term and power term, the NRL is capable of eliminating the effect of chattering on accuracy of the angular position estimation and speed estimation. Compared with conventional CRRL, the SMO with NRL achieves suppressing the chattering phenomenon and tracking the transient process rapidly and accurately. The stability analysis is given to prove the convergence of the SMO through the Lyapunov stability theory. Simulation and experimental results show the effectiveness of the proposed NRL method.


Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 33
Author(s):  
Romina Zarrabi Ekbatani ◽  
Ke Shao ◽  
Jasim Khawwaf ◽  
Hai Wang ◽  
Jinchuan Zheng ◽  
...  

The ionic polymer metal composite (IPMC) actuator is a kind of soft actuator that can work for underwater applications. However, IPMC actuator control suffers from high nonlinearity due to the existence of inherent creep and hysteresis phenomena. Furthermore, for underwater applications, they are highly exposed to parametric uncertainties and external disturbances due to the inherent characteristics and working environment. Those factors significantly affect the positioning accuracy and reliability of IPMC actuators. Hence, feedback control techniques are vital in the control of IPMC actuators for suppressing the system uncertainty and external disturbance. In this paper, for the first time an adaptive full-order recursive terminal sliding-mode (AFORTSM) controller is proposed for the IPMC actuator to enhance the positioning accuracy and robustness against parametric uncertainties and external disturbances. The proposed controller incorporates an adaptive algorithm with terminal sliding mode method to release the need for any prerequisite bound of the disturbance. In addition, stability analysis proves that it can guarantee the tracking error to converge to zero in finite time in the presence of uncertainty and disturbance. Experiments are carried out on the IPMC actuator to verify the practical effectiveness of the AFORTSM controller in comparison with a conventional nonsingular terminal sliding mode (NTSM) controller in terms of smaller tracking error and faster disturbance rejection.


Author(s):  
Carlos R. Baier ◽  
Roberto Ramirez ◽  
Esteban Ignacio Marciel ◽  
Jesus de la Casa Hernandez ◽  
Pedro Eduardo E. Melin Coloma ◽  
...  

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