1301 Friction Control Based on Ultrasonic Oscillation for Rolling Element Linear Guideway (7^ Report) : Improvement of Position Tracking Accuracy in Sinusoidal Motion

Author(s):  
Hashim SYAMSUL ◽  
Takaaki OIWA ◽  
Toshiba TANAKA ◽  
Junichi ASAMA
2019 ◽  
Vol 25 ◽  
pp. 79-82
Author(s):  
Vladimír Vinarský ◽  
Fabiana Martino ◽  
Giancarlo Forte ◽  
Jan Šleichrt ◽  
Václav Rada ◽  
...  

To investigate cellular response of cardiomyocytes to substrate mechanics, biocompatible material with stiffness in physiological range is needed. PDMS based material is used for construction of microfluidic organ on chip devices for cell culture due to ease of device preparation, bonding, and possibility of surface functionalization. However it has stiffness orders of magnitude out of physiological range. Therefore, we adapted recently available protocol aiming to prepare substrates which offer stiffness in physiological range 5−100kPa using various mixtures of Sylgard. An in-house developed loading device with single micron position tracking accuracy and sub-micron position sensitivity was adapted for this experimental campaign. All batches of the samples were subjected to uniaxial loading. During quasi-static experiment the samples were compressed to minimally 40% deformation. The results are represented in the form of stress-strain curves calculated from the acquired force and displacement data and elastic moduli are estimated.


2013 ◽  
Vol 347-350 ◽  
pp. 661-665 ◽  
Author(s):  
Wei Meng ◽  
Zu De Zhou ◽  
Quan Liu ◽  
Qing Song Ai

Multiple Degrees of Freedom (DOF) parallel robots possess the advantages of being compact structure, great stiffness, stability and high accuracy, so such platforms have been widely used in application areas as diverse as the spacecraft motion simulators, radio telescopes, and medical rehabilitation devices. In this paper, after giving a brief review on the control strategies for parallel robot, a 6-DOF robot system for medical purposes based on simulation as well as real environment is established. In order to improve the position tracking accuracy for such objects with time-varying and nonlinear parameters, a practical fuzzy adaptive controller is designed based on the kinematics of parallel platform, where fuzzy inference units are utilized to modify the PID parameters in real-time by using the position feedback from the robot actuators. Finally, both virtual and actual experiment results demonstrate that the proposed algorithm is able to effectively reduce the position tracking errors compared with the traditional PID controller, and the reliability and feasibility of such parallel robotic system can also be guaranteed.


Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2216
Author(s):  
Mingyi Wang ◽  
Kai Kang ◽  
Chengming Zhang ◽  
Liyi Li

In recent years, with the development of the permanent magnet linear synchronous motor (PMLSM), the application of PMLSM has not been limited only to the high-end equipment field; the primary stator discontinuous segmented-PMLSM (DSPMLSM), which consists of multiple primary stators and one mover, has also been applied in long-distance transportation systems, such as electromagnetic launch, high precision material transport, etc. Compared with the symmetry phase parameters of conventional PMLSM, the stationary electrical parameters vary when the mover enters and leaves the primary stators (the inter-segment region). At the same time, due to the sectional power supply, there will be primary suction or pulling force when the mover enters and exits the inter-segment region, which will lead to large thrust fluctuation and result in lager position error. This paper proposed a related drive and control strategy about the DSPMLSM system, which improved the position tracking accuracy during the full range of DSPMLSM. First, the parameter variation between stator segments has been analyzed through finite element simulation of DSPMLSM. Then, a double closed-loop series control structure of position-current is designed, in which a PI-Lead controller was adopted for the position loop and a PI controller was adopted for the current loop. In order to improve the position tracking accuracy of DSPMLSM, a thrust fluctuation extended state observer (TFESO) was adopted to observe and compensate the complex thrust disturbances such as cogging force, friction and other unmodeled thrust fluctuation. At last, the DSPMLSM experimental stage was established, and the experimental results show that the proposed driver and control theory can effectively improve the position tracking accuracy of the whole stroke of DSPMLSM.


2014 ◽  
Vol 721 ◽  
pp. 740-743
Author(s):  
Zhe Yang ◽  
Guo Zhen Tan ◽  
Fu Xin Zhang

We build an interference model to embody the influence from topological distribution, transmission power and packet transmission rate quantitatively. Then game theory is introduced. We take transmission power and position tracking accuracy as game strategy and payoff respectively. The existence of Nash equilibrium in vehicle network are proved. A Nash equilibrium is corresponding to the optimized transmission power vector for vehicles. Vehicle network self-adaptive power control algorithm (VNSPCA) is proposed to adjust transmission power in vehicle network. Finally, we conduct simulation and compare the performance of VNSPCA with MINPCA and MAXPCA.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xin Zhang ◽  
Wenbo Xu ◽  
Wenru Lu

This study aimed to improve the position tracking accuracy of the single joint of the manipulator when the manipulator model information is uncertain. The study is based on the theory of fractional calculus, radial basis function (RBF) neural network control, and iterative sliding mode control, and the RBF neural network fractional-order iterative sliding mode control strategy is proposed. First, the stability analysis of the proposed control strategy is carried out through the Lyapunov function. Second, taking the two-joint manipulator as an example, simulation comparison and analysis are carried out with iterative sliding mode control strategy, fractional-order iterative sliding mode reaching law control strategy, and fractional-order iterative sliding mode surface control strategy. Finally, through simulation experiments, the results show that the RBF neural network fractional-order iterative sliding mode control strategy can effectively improve the joints’ tracking and control accuracy, reduce the position tracking error, and effectively suppress the chattering caused by the sliding mode control. It is proved that the proposed control strategy can ensure high-precision position tracking when the information of the manipulator model is uncertain.


2001 ◽  
Vol 10 (6) ◽  
pp. 657-663 ◽  
Author(s):  
Volodymyr Kindratenko

Results of a comparison study of the tracking accuracy of two commercially available wide-range position tracking systems suitable for CAVEs are presented. An experiment was conducted with Flock of Birds and IS-900 tracking systems installed in the same CAVE environment to compare their accuracy. Another experiment was performed with a newly deployed IS-900 to investigate the impact of different ultrasound emitter configurations on the accuracy of the location tracking. The results show that the IS-900 has a much better accuracy over a larger range of operation than does the Flock of Birds; however, it is sensitive to the optimality of the ultrasound emitters configuration.


2018 ◽  
Vol 10 (11) ◽  
pp. 168781401881065
Author(s):  
Zhaoguo Wang ◽  
Xianying Feng ◽  
Peigang Li ◽  
Fuxin Du

For ball screw feed system, it has been a common practice that screw shaft is typically supported by bearings at both ends and is driven by a servo motor through coupling. However, this drive method has a relative low dynamic rigidity due to the influence of the support bearings. In this study, the nut-direct drive system is proposed, where the screw shaft is fixed at both ends and the screw nut is driven by the hollow servo motor through the bolted flange. In order to analyze the advantages of the nut-direct drive system compared with the classical drive, the dynamic models of the classical drive and the nut-direct drive are established based on lumped parameter method, respectively. According to the lumped parameter method, the influence of the table position, the length of screw shaft, and the nominal diameter of screw shaft on the natural frequency are analyzed. Furthermore, to analyze the influence of the mechanical system on position tracking accuracy, the mechanical systems of the classical drive and the nut-direct drive are integrated into the control system using the same control parameters, respectively. Results indicate that the nut-direct drive has faster responsiveness and better position tracking accuracy compared with the classical drive.


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