DYNAMICS AND IMPROVED COMPUTED TORQUE CONTROL OF A NOVEL MEDICAL PARALLEL MANIPULATOR: APPLIED TO CHEST COMPRESSIONS TO ASSIST IN CARDIOPULMONARY RESUSCITATION

2015 ◽  
Vol 15 (04) ◽  
pp. 1550051 ◽  
Author(s):  
MOHSEN ASGARI ◽  
MAHDI A. ARDESTANI
Keyword(s):  
Cardiopulmonary Resuscitation ◽  
Fuzzy Inference ◽  
Virtual Work ◽  
Parallel Manipulators ◽  
Torque Control ◽  
Chest Compressions ◽  
Inverse Dynamic ◽  
Inference System ◽  
Novel Structure ◽  
Computed Torque

In cardiopulmonary resuscitation (CPR), in practice, the rescuer usually uses two hands to perform the action of chest compressions. During chest compressions action, the two arms of the rescuer actually constitute a parallel mechanism. Inspired by this performance, this paper presents a novel structure of parallel manipulators from Delta robot family for chest compressions in rescuing a patient. Also, two new control methodologies are applied to track the desired trajectory. Based on one supervisory approach and another one based upon adaptive neuro-fuzzy inference system (ANFIS) approach. Inverse dynamic modeling is performed based on principle of virtual work and the results are verified using MSC.Adams© software. The proportional derivative (PD) controllers of computed torque (C-T) method usually need manual retuning to make a successful task, particularly in the presence of disturbance. In the present paper, we study and compare the feasibility of applying supervisory controller and ANFIS instead of conventional controller used in C-T method to cope with the above mentioned problem. Several computer simulations imply that the proposed method is encouraging compared with C-T method implemented with conventional controller.

Improved ANFIS based MRAC observer for sensorless control of PMSM

2021 ◽  
pp. 1-13
Author(s):  
Suryakant ◽  
Mini Sreejeth ◽  
Madhusudan Singh
Keyword(s):  
Fuzzy Inference ◽  
Permanent Magnet Synchronous Motor ◽  
Torque Control ◽  
Control Algorithms ◽  
Motor Speed ◽  
Inference System ◽  
Rotor Position ◽  
Improved Performance ◽  
Incremental Encoder ◽  
Model Reference Adaptive

Detection of the rotor position is an important prerequisite for controlling the speed and developed torque in permanent magnet synchronous motor (PMSM). Even though use of incremental encoder and resolver is one of the popular schemes for sensing the rotor position in a PMSM drive, it increases the size and weight of the drive and reduces its reliability. Dynamic modeling of the motor and control algorithms are often used in sensor-less control of PMSM to estimate rotor position and motor speed. Most sensor-less control algorithms use machine parameters like torque constant, stator inductances and stator resistance for estimating the rotor position and speed. However, with accuracy of such estimation and the performance of the motor degrades with variation in motor parameters. Model reference adaptive control (MRAC) provides a simple solution to this issue. An improved Adaptive neuro-fuzzy inference system (ANFIS) based MRAC observer for speed control of PMSM drive is presented in this paper. In the proposed method adaptive model and adaptive mechanism are replaced by an improved ANFIS controller, which neutralize the effect of parametric variation and results in improved performance of the drive. The modeling equations of PMSM are used to estimate the rotor position for speed and torque control of the drive. Simulation studies have been carried out under various operating condition using MATLAB/Simulink. In addition, a comparative analysis of the conventional MRAC based observer and improved ANFIS based MRAC observer is carried out. It is observed that the proposed method results in better performance of the PMSM drive.

A PD Computed Torque Control Method with Online Self-gain Tuning for a 3UPS-PS Parallel Robot

Robotica ◽  
2021 ◽  
pp. 1-13
Author(s):  
Xiaogang Song ◽  
Yongjie Zhao ◽  
Chengwei Chen ◽  
Liang’an Zhang ◽  
Xinjian Lu
Keyword(s):  
Feedback Loop ◽  
Control Method ◽  
Virtual Work ◽  
Parallel Robot ◽  
Torque Control ◽  
Virtual Work Principle ◽  
Tuning Method ◽  
Computed Torque Control ◽  
Control Feedback ◽  
Computed Torque

SUMMARY In this paper, an online self-gain tuning method of a PD computed torque control (CTC) is used for a 3UPS-PS parallel robot. The CTC is applied to the 3UPS-PS parallel robot based on the robot dynamic model which is established via a virtual work principle. The control system of the robot comprises a nonlinear feed-forward loop and a PD control feedback loop. To implement real-time online self-gain tuning, an adjustment method based on the genetic algorithm (GA) is proposed. Compared with the traditional CTC, the simulation results indicate that the control algorithm proposed in this study can not only enhance the anti-interference ability of the system but also improve the trajectory tracking speed and the accuracy of the 3UPS-PS parallel robot.

scholarly journals A Novel Comprehensive Kinematic and Inverse Dynamic Model for the Flybar-Less Swashplate Mechanism: Application on a Small-Scale Unmanned Helicopter

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1849
Author(s):  
Jianbo Liu ◽  
Rongqiang Guan ◽  
Yongming Yao ◽  
Hui Wang ◽  
Linqiang Hu
Keyword(s):  
Dynamic Model ◽  
Flight Control ◽  
Virtual Work ◽  
Influence Factors ◽  
Parallel Manipulators ◽  
Small Scale ◽  
Unmanned Helicopter ◽  
Inverse Dynamic ◽  
Inverse Dynamic Model ◽  
Helicopter Flight

In this paper, we propose a novel kinematic and inverse dynamic model for the flybar-less (FBL) swashplate mechanism of a small-scale unmanned helicopter. The swashplate mechanism is an essential configuration of helicopter flight control systems. It is a complex, multi-loop chain mechanism that controls the main rotor. In recent years, the demand for compact swashplate designs has increased owing to the development of small-scale helicopters. The swashplate mechanism proposed in this paper is the latest architectures used for hingeless rotors without a Bell-Hiller mixer. Firstly, the kinematic analysis is derived from the parallel manipulators concepts. Then, based on the principle of virtual work, a methodology for deriving a closed-form dynamic equation of the FBL swashplate mechanism is developed. Finally, the correctness and efficiency of the presented analytical model are demonstrated by numerical examples and the influence factors of the loads acted on actuators are discussed.

Minmax fuzzy deterministic policy gradient for zero-sum differential game: Take pursuit-evasion problem as example

2021 ◽  
pp. 1-14
Author(s):  
Wei Liao ◽  
Xiaohui Wei ◽  
Jizhou Lai
Keyword(s):  
Differential Game ◽  
Fuzzy Inference ◽  
Q Value ◽  
Inference System ◽  
State Action ◽  
Pursuit Evasion ◽  
Novel Structure ◽  
Policy Gradient ◽  
Evasion Problem ◽  
Zero Sum

A novel actor-critic algorithm is introduced and applied to zero-sum differential game. The proposed novel structure consists of two actors and a critic. Different actors represent the control policies of different players, and the critic is used to approximate the state-action utility function. Instead of neural network, the fuzzy inference system is applied as approximators for the actors and critic so that the specific practical meaning can be represented by the linguistic fuzzy rules. Since the goals of the players in the game are completely opposite, the actors for different players are simultaneously updated in opposite directions during the training. One actor is updated updated toward the direction that can minimize the Q value while the other updated toward the direction that can maximize the Q value. A pursuit-evasion problem with two pursuers and one evader is taken as an example to illustrate the validity of our method. In this problem, the two pursuers the same actor and the symmetry in the problem is used to improve the replay buffer. At the end of this paper, some confrontations between the policies with different training episodes are conducted.

Direct Torque Control of Induction Motor Using Enhanced Firefly Algorithm — ANFIS

2017 ◽  
Vol 26 (06) ◽  
pp. 1750092
Author(s):  
J. N. Chandra Sekhar ◽  
G. V. Marutheswar
Keyword(s):  
Induction Motor ◽  
Firefly Algorithm ◽  
Fuzzy Inference ◽  
Direct Torque Control ◽  
Torque Control ◽  
Support Vector ◽  
Hybrid Technique ◽  
Motor Speed ◽  
Inference System ◽  
Neuro Fuzzy

In this paper, the hybrid direct torque control (DTC) technique is proposed for controlling the speed of the induction motor (IM). The hybrid technique is the combination of an enhanced firefly algorithm (FA) and the adaptive neuro fuzzy inference system (ANFIS) technique. The performance of the FA is improved by updating the randomized parameter. Here, the genetic algorithm (GA) is utilized for updating the parameter and improved the performance of the FA. Initially, the actual torque and the change of toque are applied to the input of the enhanced FA and form the electromagnetic torque as a dataset. The output of the enhanced FA is given to the input of the ANFIS which is determined from the output of interference system. The dynamic behavior of the IM is analyzed in terms of the parameters such as the speed, torque, flux, etc. Based on the parameters, the motor speed is controlled by utilizing the proposed technique. Then the output of the ANFIS is translated into the stator voltage which is given to the input of the support vector machine (SVM). After that, the control signal is generated for controlling the speed of the IM. The proposed hybrid technique is implemented in the Matlab/Simulink platform. The performance analysis of the proposed method is demonstrated and contrasted with the existing techniques such as without controller, particle swarm optimization (PSO)-based ANFIS and FA-ANFIS controller.

A Survey on Control of Parallel Manipulator

2007 ◽  
Vol 339 ◽  
pp. 307-313 ◽  
Author(s):  
J.F. He ◽  
H.Z. Jiang ◽  
D.C. Cong ◽  
Zheng Mao Ye ◽  
Jun Wei Han
Keyword(s):  
Control Strategies ◽  
Parallel Manipulators ◽  
Physical Structure ◽  
Extensive Study ◽  
Torque Control ◽  
Serial Manipulators ◽  
Advanced Control ◽  
And Performance ◽  
Computed Torque ◽  
Structure Properties

Based on extensive study on literatures of control of parallel manipulators and serial manipulators, control strategies such as computed torque control, PD+ control, PD with feedforward compensation, nonlinear adaptive control are classified into two categories: model-based control and performance-based control. Besides, as advanced control strategies, robust control and passivity-based control for the parallel manipulators are also introduced. Comparative study in view of computation burden and tracking performance are performed. It turned out that the physical structure properties of parallel manipulators’ dynamics are similar with that of serial ones, and this constitutes a common foundation for the two kinds of manipulators to develop together that control design of parallel manipulators can start with ever established control methods of serial manipulators.

Model-based joint and task space control strategies for a kinematically redundant parallel manipulator

Robotica ◽  
2021 ◽  
pp. 1-17
Author(s):  
João Vitor de Carvalho Fontes ◽  
Fernanda Thaís Colombo ◽  
Natássya Barlate Floro da Silva ◽  
Maíra Martins da Silva
Keyword(s):  
Parallel Manipulator ◽  
Control Strategies ◽  
Parallel Manipulators ◽  
Torque Control ◽  
Redundancy Resolution ◽  
Task Space ◽  
Kinematic Redundancy ◽  
Model Based ◽  
The Impact ◽  
Computed Torque

Abstract One alternative to overcome the presence of singularities within Parallel Manipulators’ workspace is kinematic redundancy. This design alternative can be realized by adding an extra active joint to a kinematic chain. Due to this addition, the IKM presents an infinite number of solutions requiring a redundancy resolution scheme. Moreover, Parallel Manipulators’ control may require complex strategies due to their coupled and complex dynamic and kinematic relations. In this work, a model-free, a joint space computed torque, and a hybrid joint-task-space computed torque control strategies are experimentally compared for a kinematically redundant parallel manipulator. The latter is a novel strategy that requires the measurement of the end-effector’s pose, which is performed by an eye-to-hand limited frame rate camera. The impact of up to three kinematic redundancy levels is also experimentally evaluated using prepositioning and ongoing positioning redundancy resolution schemes. The data are assessed by evaluating a prescribed trajectory executed using a planar kinematically redundant parallel manipulator. These results indicate that kinematic redundancy can not only be used as an alternative design for reducing the presence of singular regions, as claimed in the literature, but also be used along with model-based control strategies for improving dynamic performance and accuracy of parallel manipulators.

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