A Finger-Motion Adaptive Algorithm for Braille Reading: Application of Active Disturbance Rejection Control

Volume 1: Adaptive and Intelligent Systems Control; Advances in Control Design Methods; Advances in Non-Linear and Optimal Control; Advances in Robotics; Advances in Wind Energy Systems; Aerospace Applications; Aerospace Power Optimization; Assistive Robotics; Automotive 2: Hybrid Electric Vehicles; Automotive 3: Internal Combustion Engines; Automotive Engine Control; Battery Management; Bio Engineering Applications; Biomed and Neural Systems; Connected Vehicles; Control of Robotic Systems ◽

10.1115/dscc2015-9965 ◽

2015 ◽

Author(s):

Melda Ulusoy ◽

Rifat Sipahi

Keyword(s):

Real Time ◽

Disturbance Rejection ◽

Active Disturbance Rejection Control ◽

Motion Adaptation ◽

Reading Experience ◽

Active Disturbance Rejection ◽

Disturbance Rejection Control ◽

Internal Disturbance ◽

Finger Touch ◽

Finger Motion

Currently existing refreshable Braille displays suffer from high costs, which prevent their affordability. A rotating wheel with refreshable Braille and utilizing finger-motion adaptation can help create realistic Braille reading experience, while significantly reducing the high costs by offsetting the number of actuators needed to display Braille. In this paper, we design a real-time controller to adjust the speed of the rotating wheel system based on the finger motions of the user. Due to unknown dynamics of the rotating wheel system, active disturbance rejection control (ADRC) has been implemented to estimate the total disturbance acting on the system. This estimate is then used to eliminate the internal disturbance of the system so that disturbances associated with finger touch on the wheel can be predicted. Real-time experimental results show that even without the knowledge of the system model, it is possible to adapt the speed of the rotating wheel based on these finger touch predictions.

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Robust error-based active disturbance rejection control of a quadrotor

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-12-2019-0266 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Taki Eddine Lechekhab ◽

Stojadin Manojlovic ◽

Momir Stankovic ◽

Rafal Madonski ◽

Slobodan Simic

Keyword(s):

Real Time ◽

Time Domain ◽

Disturbance Rejection ◽

Active Disturbance Rejection Control ◽

Content Type ◽

Advantages And Disadvantages ◽

Quadrotor Control ◽

Active Disturbance Rejection ◽

Disturbance Rejection Control ◽

Highly Nonlinear

Purpose The control of a quadrotor unmanned aerial vehicle (UAV) is a challenging problem because of its highly nonlinear dynamics, under-actuated nature and strong cross-couplings. To solve this problem, this paper aims to propose a robust control strategy, based on a concept of active disturbance rejection control (ADRC). Design/methodology/approach The altitude/attitude dynamics of a quadrotor is reformulated into the ADRC framework. Three distinct variations of the error-based ADRC algorithms, with different structures of generalized extended state observers (GESO), are derived for the altitude/attitude trajectory-following task. The convergence of the observation part is proved based on the singular perturbation theory. Through a frequency analysis and a quantitative comparison in a simulated environment, each design is shown to have certain advantages and disadvantages in terms of tracking accuracy and robustness. The digital prototypes of the proposed controllers for quadrotor altitude and attitude control channels are designed and validated through real-time hardware-in-the-loop (HIL) co-simulation, with field-programmable gate array (FPGA) hardware. Findings The effects of unavailable reference time-derivatives can be estimated by the ESO and rejected through the outer control loop. The higher order ESOs demonstrate better performances, but with reductions of stability margins. Time-domain simulation analysis reveals the benefits of the proposed control structure related to classical control approach. Real-time FPGA-based HIL co-simulations validated the performances of the considered digital controllers in typical quadrotor flight scenarios. Practical implications The conducted study forms a set of practical guidelines for end-users for selecting specific ADRC design for quadrotor control depending on the given control objective and work conditions. Furthermore, the paper presents detailed procedure for the design, simulation and validation of the embedded FPGA-based quadrotor control unit. Originality/value In light of the currently available literature on error-based ADRC, a comprehensive approach is applied here, which includes the design of error-based ADRC with different GESOs, its frequency-domain and time-domain analyses using different simulation of UAV flight scenarios, as well as its FPGA-based implementation and testing on the real hardware.

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Based on Robust Sliding Mode and Linear Active Disturbance Rejection Control for Attitude of Quadrotor Load UAV

10.21203/rs.3.rs-735025/v1 ◽

2021 ◽

Author(s):

Zhaoji Wang ◽

Tong Zhao

Keyword(s):

Adaptive Control ◽

Real Time ◽

Disturbance Rejection ◽

Control Method ◽

Sliding Mode ◽

Reference Signal ◽

Active Disturbance Rejection Control ◽

Mass Variation ◽

Active Disturbance Rejection ◽

Disturbance Rejection Control

Abstract In this paper, a mass adaptive control method combining robust sliding mode control (SMC) and linear active disturbance rejection control (LADRC) is designed for the quadrotor load unmanned aerial vehicle (UAV) with mass variation. The scheme combines the advantages of SMC and LADRC. SMC can enhance the robustness of the controller, improve the anti-disturbance performance and overcome the problem of low control precision caused by bandwidth limitation of LADRC. The linear extended state observer (LESO) can estimate the external and internal disturbances of the system in real time, and then compensate the total disturbance through the PD controller. In order to simplify parameter setting, adaptive control is introduced in LADRC to adjust controller parameters in real time. In addition, adaptive law is also used to control the mass variation of the quadrotor. Then the stability of the whole system is verified by Lyapunov stability theory. Finally, the comparison with LADRC shows the superiority of the designed scheme, which can track the reference signal stably and effectively.

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