Hybrid Analog/Digital Control of Bilateral Teleoperation Systems

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Ting Yang ◽  
Junfeng Hu ◽  
Wei Geng ◽  
Dan Wang ◽  
Yili Fu ◽  
...  
Keyword(s):  
Digital Control ◽  
Hybrid Control ◽  
Sampling Period ◽  
Superior Performance ◽  
Digital Controller ◽  
Bilateral Teleoperation ◽  
Success Rates ◽  
Hybrid Controller ◽  
Derivative Term ◽  
Teleoperation Systems

Hybrid analog/digital control of bilateral teleoperation systems can lead to superior performance (transparency) while maintaining stability compared to pure analog or digital control methods. Such hybrid control is preferable over pure analog control, which is inflexible and not ideal for realizing complex teleoperation control algorithms, and pure digital control, which restricts teleoperation performance due to a well-known stability-imposed upper bound on the product of the digital controller's proportional gain and the sampling period. In this paper, a hybrid controller combining a Field programmable analog array (FPAA) based analog controller and a personal computer-based digital controller is compared in terms of performance and stability to its analog and digital counterparts. A stability analysis indicates that the addition of analog derivative term widens the range of teleoperation controls gains that satisfy the stability conditions, paving the way for improving the teleoperation performance. We also show how the hybrid controller leads to better teleoperation performance. To this end, we study the human's performance of a switch flipping task and a stiffness discrimination task in the teleoperation mode. In both tasks, the hybrid analog/digital controller allows the human operators to achieve the highest task success rates.

scholarly journals A New Hybrid Controller for Standalone Photovoltaic Power System with Unbalanced Loads

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammad Pichan ◽  
Hasan Rastegar
Keyword(s):  
Power System ◽  
Reference Frames ◽  
Control Method ◽  
Experimental Tests ◽  
Superior Performance ◽  
Digital Controller ◽  
Well Performance ◽  
Alternative Source ◽  
Digital Implementation ◽  
Hybrid Controller

Due to several problems such as global concern about environmental pollution, renewable energy has become an alternative source of energy. In situations such as small local loads far from the main grid, standalone hybrid power system (HPS) with inevitable unbalanced loading condition is preferred for the global grid. The four-leg inverter with a simple as well as well-performance control method is a good solution to support this condition. In this paper, with respect to the average and discretized model of the inverter, a new digital controller is proposed in the abc reference frame to control the load voltages. The proposed controller offers several advantages such as simplicity, fast dynamic response, no need for transformation among different reference frames, and full compatibility with digital implementation which makes it as an excellent option to be employed in such systems. In addition, a new hybrid controller is also proposed which not only has the advantages of the proposed digital controller but also shows superior performance under nonlinear loads without imposing a high computational burden. To verify the effectiveness of the two proposed controllers, several simulation and experimental tests under different scenarios on a 3 kW setup are performed.

FPAA-Based Control of Bilateral Teleoperation Systems for Enhanced User Task Performance

2017 ◽  
Vol 26 (2) ◽  
pp. 210-227 ◽  
Author(s):  
Ting Yang ◽  
Junfeng Hu ◽  
Wei Geng ◽  
Yili Fu ◽  
Mahdi Tavakoli
Keyword(s):  
Task Performance ◽  
Discrete Time ◽  
Sampling Period ◽  
Bilateral Teleoperation ◽  
System A ◽  
Programmable Analog ◽  
Teleoperation System ◽  
Field Programmable ◽  
Teleoperation Systems ◽  
Field Programmable Analog Array

In a bilateral teleoperation system, discrete-time implementation of the controller can cause performance degradation. This is due to a well-known stability-imposed upper bound on the product of the discrete-time controller's gain and the sampling period. In this article, for a bilateral teleoperation system, a continuous-time controller based on a Field Programmable Analog Array (FPAA) is deployed and compared in terms of performance with its discrete-time counterpart. Experimental results show that, unlike the discrete-time controller, the FPAA-based controller helps the human user complete teleoperation tasks that require high controller gains such as when a large impedance needs to be displayed against the user's hand. Also, an experimental object stiffness discrimination study shows that large sampling periods, necessitating low control gains for maintaining stability, lead to unacceptable task performance by the user; however, the users show an improved ability to discriminate the various objects if the teleoperation controller is implemented using an FPAA.

scholarly journals Design and Simulation of Eight-Rotor Unmanned Aerial Vehicle Based on Hybrid Control System

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xueqiang Shen ◽  
Jiwei Fan ◽  
Haiqing Wang
Keyword(s):  
Control System ◽  
Unmanned Aerial Vehicle ◽  
Flight Control ◽  
Hybrid Control ◽  
Dynamic Performance ◽  
System Response ◽  
Hybrid Controller ◽  
Aerial Vehicle ◽  
Switching Method ◽  
Hybrid Control System

In order to control the position and attitude of unmanned aerial vehicle (UAV) better in different environments, this study proposed a hybrid control system with backstepping and PID method for eight-rotor UAV in different flight conditions and designed a switching method based on altitude and attitude angle of UAV. The switched process of hybrid controller while UAV taking off, landing, and disturbance under the gust is verified in MATLAB/Simulink. A set of appropriate controllers always matches to the flight of UAV in different circumstances, which can speed up the system response and reduce the steady-state error to improve stability. The simulation results show that the hybrid control system can suppress the drift efficiently under gusts, enhance the dynamic performance and stability of the system, and meet the position and attitude of flight control requirements.

Transparent four-channel bilateral control architecture using modified wave variable controllers under time delays

Robotica ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 859-875 ◽  
Author(s):  
Da Sun ◽  
Fazel Naghdy ◽  
Haiping Du
Keyword(s):  
Time Delays ◽  
Large Time ◽  
Wave Transformation ◽  
Bilateral Teleoperation ◽  
Bilateral Control ◽  
Wave Variable ◽  
Guarantee System ◽  
Remote Environment ◽  
The Stability ◽  
Teleoperation Systems

SUMMARYStability and transparency are two critical indices of bilateral teleoperation systems. The wave variable method is a conservative approach to robustly guarantee system passivity under arbitrary constant time delays. However, the wave-variable-based reflection is an intrinsic problem in this method because it can significantly degrade system transparency and disorient the operator's perception of the remote environment. In order to enhance both the transparency and the stability of bilateral teleoperation systems in the presence of large time delays, a new four-channel (4-CH) architecture is proposed which applies two modified wave-transformation controllers to reduce wave-based reflections. Transparency and stability of the proposed system are analyzed and the improvement in these when using this method is measured experimentally. Results clearly demonstrate that the proposed method can produce high transparency and stability even in the presence of large time delays.

STATE-SPACE SELF-TUNING CONTROL FOR NONLINEAR STOCHASTIC AND CHAOTIC HYBRID SYSTEMS

2001 ◽  
Vol 11 (04) ◽  
pp. 1079-1113 ◽  
Author(s):  
SHU-MEI GUO ◽  
LEANG-SAN SHIEH ◽  
CHING-FANG LIN ◽  
JAGDISH CHANDRA
Keyword(s):  
State Space ◽  
Hybrid Systems ◽  
Continuous Time ◽  
Digital Control ◽  
Stochastic Systems ◽  
Moving Average ◽  
Computation Time ◽  
Sampling Period ◽  
Noise Model ◽  
Self Tuning

This paper presents a new state-space self-tuning control scheme for adaptive digital control of continuous-time multivariable nonlinear stochastic and chaotic systems, which have unknown system parameters, system and measurement noises, and inaccessible system states. Instead of using the moving average (MA)-based noise model commonly used for adaptive digital control of linear discrete-time stochastic systems in the literature, an adjustable auto-regressive moving average (ARMA)-based noise model with estimated states is constructed for state-space self-tuning control of nonlinear continuous-time stochastic systems. By taking advantage of a digital redesign methodology, which converts a predesigned high-gain analog tracker/observer into a practically implementable low-gain digital tracker/observer, and by taking the non-negligible computation time delay and a relatively longer sampling period into consideration, a digitally redesigned predictive tracker/observer has been newly developed in this paper for adaptive chaotic orbit tracking. The proposed method enables the development of a digitally implementable advanced control algorithm for nonlinear stochastic and chaotic hybrid systems.

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