Motion control with robust string stability of mobile-rack vehicles in autonomous logistics

2020 ◽  
pp. 095440622095317
Author(s):  
Boc Minh Hung ◽  
Sam-Sang You ◽  
Bui Duc Hong Phuc ◽  
Hwan-Seong Kim
Keyword(s):  
Control Method ◽  
Order System ◽  
Robust Controller ◽  
String Stability ◽  
Storage And Retrieval ◽  
Working Space ◽  
Vehicle System ◽  
Efficient Storage ◽  
Control Stability ◽  
Safe Working

In order to reduce costs for a larger warehouse or expand the floor space of a small warehouse, it is impossible to implement this with a traditional warehouse, which is characterized as poorly utilized space. For the efficient storage and retrieval, the smart warehouse system with autonomous mobile-rack vehicles can optimize the space utilization by providing only a few open aisles at a time for accessing the racks with minimal intervention. This paper deals with designing the vehicle robust controller for maintaining safe spacing with collision avoidance in the fully automated warehouse. The compact vehicle dynamics are presented for the interconnected string of vehicles. Next, the string stability with safe working space of the mobile-rack vehicles has been described for guaranteeing complete autonomous logistics in smart warehouse. In addition, the controller order has been significantly reduced to a low-order system without performance degradation for real implementation. This control method can guarantee control stability as well as performances of mobile-rack vehicles against unavoidable uncertainties, disturbances, and noises for warehouse automation in the extremely cold environment without rail rack. Finally, the autonomous mobile-rack vehicle system is to become the promising vision of future smart warehouse technology in autonomous logistics.

scholarly journals The Novel Singular-Perturbation-Based Adaptive Control with σ-Modification for Cable Driven System

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 45
Author(s):  
Bin Li ◽  
Liang Yan ◽  
Chris Gerada
Keyword(s):  
Adaptive Control ◽  
Singular Perturbation ◽  
Control Method ◽  
Fast Response ◽  
Order System ◽  
Estimation Errors ◽  
High Frequencies ◽  
Flexible System ◽  
Working Space ◽  
Driven System

Due to their large working space and fast response, cable driven systems have been widely applied in manufacturing, robotics and motion simulators, etc. However, the cable is flexible and tends to resonate at high frequencies, which raises challenges for the motion control of the cable driven system. To solve this problem, this paper proposes a singular-perturbation-based adaptive control method with σ-modification. Taking advantage of the multi-time scale characteristics, the flexible system is approximately decomposed into two subsystems, and then the damping compensation is designed in the boundary layer subsystem to enhance the tension stability. In addition, estimated parameters drift may occur for the reduced-order system. Thus, the σ-modification is proposed to ensure that the tracking and estimation errors converge to a bounded residual set. The Lyapunov stability theorem proves that the closed-loop system is stable and errors are ultimately uniformly bounded. A research prototype of a twin-motor cable driven system is developed, and experimental investigation is conducted on it. The experimental results show that the proposed control method can effectively suppress cable resonance at high frequencies. Compared with the conventional adaptive control method, it can significantly increase the system bandwidth.

Design and Implementation of Efficient Storage and Retrieval Technology of Traffic Big Data

2019 ◽  
Vol 4 (2) ◽  
pp. 207-220
Author(s):  
김기수 ◽  
Yukun Hahm ◽  
장유림 ◽  
Jaejin Yi ◽  
HONGHOI KIM
Keyword(s):  
Big Data ◽  
Storage And Retrieval ◽  
Design And Implementation ◽  
Efficient Storage

The Design and Simulation for Two-Link Manipulators PD Robust Controller under Uncertain Upper Bound Disturbance

2013 ◽  
Vol 694-697 ◽  
pp. 1652-1655
Author(s):  
Ji Yan Wang
Keyword(s):  
Dynamic Characteristics ◽  
Upper Bound ◽  
Control Method ◽  
Robot Manipulator ◽  
Industrial Robot ◽  
Pd Controller ◽  
Robust Controller ◽  
Convergence And Stability ◽  
Comparison And Analysis ◽  
Driving Torque

PD control method is widely utilized for the dynamic characteristics controlling in industrial robot manipulator area. The disturbance is usually uncertain in reality; the traditional PD controller is limited in that case. In this paper, a PD robust controller is introduced to optimize the convergence and stability of PD controller and avoid the extreme initial driving torque for two-link manipulator system. Using the co-simulation on Matlab/ Simulink and ADAMS, the paper designs a PD robust controller under uncertain upper bound disturbance and completes track control and driving torque simulation trial. The superiority of the two-link manipulators PD robust controller is verified through result comparison and analysis.

Modified Posicast Control Design Method Based on the Parameters of a Fractional Order System

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Erhan Yumuk ◽  
Müjde Güzelkaya ◽  
İbrahim Eksin
Keyword(s):  
Real Time ◽  
Fractional Order ◽  
Control Method ◽  
Design Method ◽  
Order System ◽  
Half Cycle ◽  
Empirical Formulas ◽  
Real Time System ◽  
Novel Design ◽  
Better Than

Abstract In this study, a novel design method for half-cycle and modified posicast controller structures is proposed for a class of the fractional order systems. In this method, all required design variable values, namely, the input step magnitudes and their application times are obtained as functions of fractional system parameters. Moreover, empirical formulas are obtained for the overshoot values of the compensated system with half-cycle and modified posicast controllers designed utilizing this method. The proposed design methodology has been tested via simulations and ball balancing real-time system. It is observed that the derived formulas are in coherence with outcomes of the simulation and real-time application. Furthermore, the performance of modified posicast controller designed using proposed method is much better than other posicast control method.

scholarly journals Genetic association testing using the GENESIS R/Bioconductor package

2019 ◽  
Author(s):  
Stephanie M Gogarten ◽  
Tamar Sofer ◽  
Han Chen ◽  
Chaoyu Yu ◽  
Jennifer A Brody ◽  
...  
Keyword(s):  
Data Storage ◽  
Genomic Analysis ◽  
Supplementary Information ◽  
Storage And Retrieval ◽  
Association Testing ◽  
Link Functions ◽  
Efficient Storage ◽  
Genetic Association Testing ◽  
Analysis Workflow ◽  
Complete Genomic

Abstract Summary The Genomic Data Storage (GDS) format provides efficient storage and retrieval of genotypes measured by microarrays and sequencing. We developed GENESIS to perform various single- and aggregate-variant association tests using genotype data stored in GDS format. GENESIS implements highly flexible mixed models, allowing for different link functions, multiple variance components and phenotypic heteroskedasticity. GENESIS integrates cohesively with other R/Bioconductor packages to build a complete genomic analysis workflow entirely within the R environment. Availability and implementation https://bioconductor.org/packages/GENESIS; vignettes included. Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals Current Prediction-Based Three-Vector Voltage Optimization System for the Induction Motor with Current Static Error Correction

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Li Haixia ◽  
Lin Jican
Keyword(s):  
Steady State ◽  
Model Predictive Control ◽  
Induction Motor ◽  
Predictive Control ◽  
Control Method ◽  
Tracking Error ◽  
Current Control ◽  
Static Error ◽  
Control Stability ◽  
Steady State Performance

In the present study, the current control method of the model predictive control is applied to the field-oriented control induction motor. The augmentation model of the motor is initially established based on the stator current equation, which performs the current predictive control and formulates the new cost function by means of tracking error. Then, the influence of parameter error on the current control stability in the prediction model is analysed, and the current static error is corrected according to the correlation between the input and feedback. Finally, a simple and effective three-vector control strategy is proposed. Moreover, three adjacent basic voltage vectors are utilized, and then six candidate voltage vectors are synthesized in each sector to replace eight basic voltage vectors in the conventional model predictive control (MPC). The obtained results show that synthesized vectors, which have arbitrary amplitude and direction, significantly expand the coverage of the system’s control set, reduce the torque and flux pulsation in the conventional MPC, and improve the steady-state performance of the system. Finally, the dSPACE platform is employed to validate the performed experiment. It is concluded that the proposed method can reduce the torque and flux pulse, perform the induction motor current control, and improve the steady-state performance of the system.

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