Robust passive tracking control for an uncertain soft actuator using robust right coprime factorization

2021 ◽  
Author(s):  
Ni Bu ◽  
Haoyu Liu ◽  
Wenpeng Li
Keyword(s):  
Tracking Control ◽  
Soft Actuator ◽  
Coprime Factorization ◽  
Passive Tracking

Nonlinear Perfect Tracking Control for a Robot Arm with Uncertainties Using Operator-Based Robust Right Coprime Factorization Approach

2015 ◽  
Vol 27 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Aihui Wang ◽  
◽  
Dongyun Wang ◽  
Haiquan Wang ◽  
Shengjun Wen ◽  
...  
Keyword(s):  
Tracking Control ◽  
Structural Parameters ◽  
Control System Design ◽  
Robot Arm ◽  
External Disturbances ◽  
Factorization Approach ◽  
Coprime Factorization ◽  
Tracking Condition ◽  
Control Scheme ◽  
Universal Stability

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00270001/06.jpg"" width=""300"" />Plant uncertainties compensation</div> In this paper, a robust nonlinear perfect tracking control for a robot arm with uncertainties is proposed by using operator-based robust right coprime factorization approach. In general, there exist unknown modelling errors in measuring structural parameters of the robot arm and external disturbances in real situations. In the present control system design, the effect of the modelling errors and disturbances on the system performance is considered to be uncertainties of the robot arm dynamics. Considering the uncertainties, a robust nonlinear perfect tracking control using operator-based robust right coprime factorization is investigated. That is, first, considering the unknown uncertain plant generates limitations in obtaining the so-called universal stability and tracking conditions, the effect of uncertain plant is compensated by designed operator-based feedback control scheme. Second, a new perfect tracking condition is proposed for improving the trajectory of the robot arm. Finally, the effectiveness of the designed system is confirmed by simulation results. </span>

scholarly journals Operator-Based Nonlinear Control for a Miniature Flexible Actuator Using the Funnel Control Method

Machines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 26
Author(s):  
Keisuke Ueno ◽  
Shuhei Kawamura ◽  
Mingcong Deng
Keyword(s):  
Nonlinear Control ◽  
Tracking Control ◽  
Control Method ◽  
Boundary Function ◽  
Soft Actuator ◽  
Design Scheme ◽  
Adaptive Law ◽  
Control Gain ◽  
Soft Actuators ◽  
Funnel Control

Recently, the studies of soft actuators have been getting increased attention among various fields. Soft actuators are very safe for fragile objects and have an affinity to humans because they are composed of flexible materials. A miniature flexible actuator is a kind of pneumatically driven soft actuator. It has a bellowed shape and asymmetrical structure. This shape can generate a curling motion in two ways under positive and negative pressures with only one air tube. In the previous article, a control system using adaptive λ-tracking control was proposed. This control gain can become too large as time tends to infinity because the adaptive law exhibits a non-decreasing gain. To solve this problem, the funnel control method is proposed. The adaptive gain of this method not only increases but also decreases; however, the design scheme of the boundary function which is needed to decide on adaptive gain is not proposed here. In this article, an operator-based nonlinear control system’s design and the design scheme of the boundary function using an observer are proposed. Then, the effectiveness of the proposed method is verified by a simulation and an experiment.

Operator-Based Robust Nonlinear Control Design and Analysis of a Semiconductor Refrigeration Device

2017 ◽  
Vol 29 (6) ◽  
pp. 1065-1072 ◽  
Author(s):  
Aihui Wang ◽  
Zhengxiang Ma ◽  
Shengjun Wen ◽  
◽  
◽  
...  
Keyword(s):  
Robust Stability ◽  
Tracking Control ◽  
Control Design ◽  
Aluminum Plate ◽  
Control Performance ◽  
Robust Tracking Control ◽  
Factorization Approach ◽  
Coprime Factorization ◽  
State Observers ◽  
Peltier Device

In this paper, an operator-based robust perfect control for nonlinear semiconductor refrigeration device with uncertainties and perturbation is considered. For the research about the properties of the semiconductor refrigeration, an aluminum plate with Peltier device is very representative. Therefore, the perfect tracking control performance of semiconductor refrigeration can be investigated by using this aluminum plate with Peltier device. Moreover, the operator based robust right coprime factorization (RRCF) approach is convenient in analysis and designing control system of nonlinear plant with uncertainties and perturbation. Based on the above reasons, an operator-based robust tracking control design for nonlinear semiconductor refrigeration device with uncertainties and perturbation is investigated by using an operator-based robust right coprime factorization approach, where the operator-based disturbance and state observers based on nominal plant properties are designed to compensate the effect of uncertainties and perturbation. A realizable operator controller is designed to improve the control performance and to realize the perfect tracking. The sufficient condition of robust stability for the designed system is derived. The robust stability condition ensured that the output tracking performance is realized. Finally, the effectiveness of the proposed design scheme was illustrated by the simulation and experimental results.

Robust nonlinear tracking control system design of an uncertain multivariable process driven by a distributed control system device

2015 ◽  
Vol 39 (4) ◽  
pp. 520-536 ◽  
Author(s):  
Kohsuke Furukawa ◽  
Mingcong Deng
Keyword(s):  
Control System ◽  
Water Level ◽  
Control Systems ◽  
Distributed Control ◽  
Tracking Control ◽  
Distributed Control System ◽  
Nonlinear Feedback ◽  
Coupling Effects ◽  
Robust Tracking Control ◽  
Coprime Factorization

In this paper, by using a distributed control system (DCS) device, a robust tracking control system is proposed based on robust right coprime factorization for a heat exchanger actuated by a water level process with coupling effects and uncertainties. Firstly, nonlinear models of water level and temperature processes with coupling and uncertainties are given. Secondly, nonlinear feedback tracking control systems corresponding to a multi-input multi-output (MIMO) process are realized by using operator-based robust right coprime factorization. Meanwhile, stability of the control systems is guaranteed by using robust stability conditions compatible with the MIMO process including coupling effects, and to improve the output tracking performance, tracking controllers are designed. Finally, the effectiveness of the proposed design scheme is confirmed by simulation and experimental results.

Performance study of RTV-2 Silicone Rubber Material For Soft Actuator by Experimental and Numerical methods: The Effect of Inflation Pressure and Wall Thickness

2020 ◽  
Vol 17 (1) ◽  
pp. 7524-7532 ◽  
Author(s):  
Deepak D. ◽  
Nitesh Kumar ◽  
Shreyas P. Shetty ◽  
Saurabh Jain ◽  
Manoj Bhat
Keyword(s):  
Numerical Methods ◽  
Wall Thickness ◽  
Silicone Rubber ◽  
Inflation Pressure ◽  
Performance Study ◽  
Rubber Material ◽  
Soft Actuator ◽  
Alternative Materials ◽  
Load Carrying ◽  
Influential Parameters

The expensive nature of currently used materials in the soft robotic industry demands the consideration of alternative materials for fabrication. This work investigates the performance of RTV-2 grade silicone rubber for fabrication of a soft actuator. Initially, a cylindrical actuator is fabricated using this material and its performance is experimentally assessed for different pressures. Further, parametric variations of the effect of wall thickness and inflation pressure are studied by numerical methods. Results show that, both wall thickness and inflation pressure are influential parameters which affect the elongation behaviour of the actuator. Thin (1.5 mm) sectioned actuators produced 76.97% more elongation compared to thick sectioned, but the stress induced is 89.61 % higher. Whereas, the thick sectioned actuator (6 mm) showed a higher load transmitting capability. With change in wall thickness from 1.5 mm to 6 mm, the elongation is reduced by 76.97 %, 38.35 %, 21.05 % and 11.43 % at pressure 100 kPa, 75 kPa, 50 kPa and 25 kPa respectively. The induced stress is also found reduced by 89.61 %, 86.66 %, 84.46 % and 68.68 % at these pressures. The average load carrying capacity of the actuator is found to be directly proportional to its wall thickness and inflation pressure.

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