Hybrid force/position control for quasi continuum manipulators

2020 ◽  
Vol 68 (10) ◽  
pp. 854-862
Author(s):  
Daniel Müller ◽  
Carina Veil ◽  
Oliver Sawodny
Keyword(s):  
Position Control ◽  
Control Strategies ◽  
Industrial Applications ◽  
Production Costs ◽  
Center Point ◽  
Continuum Manipulators ◽  
Position Controller ◽  
Promising Solution ◽  
Industrial Task ◽  
Existing Structure

AbstractThe inherent compliant and safe structure of fluid driven continuum manipulators makes them a promising solution for various tasks. Despite their cheap production costs these robots have yet not found their way into industrial applications. This is due to the lack of precise models as well as control strategies which are both open fields of research.A basic industrial task is to control the force the manipulator exerts at its tool center point on a given object. In this work we present a hybrid force/position controller (HFPC) for the Bionic Soft Arm (BSA). It is assumed that contact is only established at the tool center point where the contact force can be measured. Further, we show how to extend the basic HFPC approach in order to overcome model inaccuracies. Experimental results are provided for the BSA where the HFPC is incorporated into an existing structure.

scholarly journals Sliding mode control of pam actuator in LabVIEW environment

2010 ◽  
Vol 5 (1-2) ◽  
pp. 249-253
Author(s):  
János Gyeviki ◽  
József Sárosi ◽  
Antal Véha ◽  
Péter Toman
Keyword(s):  
Flow Rate ◽  
Position Control ◽  
Control Method ◽  
Sliding Mode ◽  
Artificial Muscle ◽  
Industrial Applications ◽  
Pneumatic Artificial Muscle ◽  
Air Mass ◽  
Pneumatic Muscle ◽  
Position Controller

As an important driver element, the pneumatic artificial muscle (PAM) is widely used in industrial applications for many automation purposes thanks to their variety of advantages. The design of a stable robust position controller for PAM is difficult since it is a very nonlinear time-variant controlled plant because of the compressibility of air, air mass flow rate through the valve, etc. The main contribution of this paper is a robust position control method based on sliding mode for pneumatic muscle actuator. Finally, it presents experimental results.

Robust Two-degree-of-freedom Control Based on H∞ Method for PMSM Drive System

2020 ◽  
Vol 13 (4) ◽  
pp. 496-506
Author(s):  
Qixin Zhu ◽  
Lei Xiong ◽  
Hongli Liu ◽  
Yonghong Zhu ◽  
Guoping Zhang
Keyword(s):  
Control System ◽  
Control Theory ◽  
Position Control ◽  
Dynamic Performance ◽  
Servo System ◽  
Degree Of Freedom ◽  
Trade Off ◽  
Standard Design ◽  
Position Controller ◽  
Two Degree Of Freedom

Background: The conventional method using one-degree-of-freedom (1DOF) controller for Permanent Magnet Synchronous Motor (PMSM) servo system has the trade-off problem between the dynamic performance and the robustness. Methods: In this paper, by using H∞ control theory, a novel robust two-degree-of-freedom (2DOF) controller has been proposed to improve the position control performance of PMSM servo system. Using robust control theory and 2DOF control theory, a H∞ robust position controller has been designed and discussed in detail. Results: The trade-off problem between the dynamic performance and robustness which exists in one-degree-of-freedom (1DOF) control can be dealt with by the application of 2DOF control theory. Then, through H∞ control theory, the design of robust position controller can be translated to H∞ robust standard design problem. Moreover, the control system with robust controller has been proved to be stable. Conclusion: Further simulation results demonstrate that compared with the conventional PID control, the designed control system has better robustness and attenuation to the disturbance of load impact.

scholarly journals Metal-free oxidative cross-coupling enabled practical synthesis of atropisomeric QUINOL and its derivatives

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng-Ying Jiang ◽  
Kai-Fang Fan ◽  
Shaoyu Li ◽  
Shao-Hua Xiang ◽  
Bin Tan
Keyword(s):  
Asymmetric Catalysis ◽  
Kinetic Resolution ◽  
Academic Research ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Industrial Applications ◽  
Lewis Base ◽  
Production Costs ◽  
Metal Free ◽  
Base Catalysts

AbstractAs an important platform molecule, atropisomeric QUINOL plays a crucial role in the development of chiral ligands and catalysts in asymmetric catalysis. However, efficient approaches towards QUINOL remain scarce, and the resulting high production costs greatly impede the related academic research as well as downstream industrial applications. Here we report a direct oxidative cross-coupling reaction between isoquinolines and 2-naphthols, providing a straightforward and scalable route to acquire the privileged QUINOL scaffolds in a metal-free manner. Moreover, a NHC-catalyzed kinetic resolution of QUINOL N-oxides with high selectivity factor is established to access two types of promising axially chiral Lewis base catalysts in optically pure forms. The utility of this methodology is further illustrated by facile transformations of the products into QUINAP, an iconic ligand in asymmetric catalysis.

scholarly journals Present and Future of Supercapacitor Technology Applied to Powertrains, Renewable Generation and Grid Connection Applications

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3060
Author(s):  
Gustavo Navarro ◽  
Jorge Torres ◽  
Marcos Blanco ◽  
Jorge Nájera ◽  
Miguel Santos-Herran ◽  
...  
Keyword(s):  
Energy Storage ◽  
Control Strategies ◽  
Industrial Applications ◽  
Frequency Regulation ◽  
Scientific Publications ◽  
Industrial Systems ◽  
Grid Connection ◽  
Huge Impact ◽  
Traction Drives ◽  
Electric Traction

Energy storage systems (ESS) are becoming essential as a solution for troublesome industrial systems. This study focuses on the application of a type of ESS, a high-power technology known in the literature as supercapacitors or electric double layer capacitors (EDLC). This technology has had a huge impact during the last decade on research related to the electric traction drives, renewable sources and powergrids. Related to this aspect, this paper summarizes the most relevant scientific publications in the last five years that study the use of supercapacitor technology (SCs) in electric traction applications (drives for rail vehicles and drives for road vehicles), generation systems for renewable energy (wind, solar and wave energy), and connection systems to the electric grid (voltage and frequency regulation and microgrids). The technology based on EDLC and the practical aspects that must be taken into account in the op-eration of these systems in industrial applications are briefly described. For each of the aforementioned applications, it is described how the problems are solved by using the energy storage technology, drawing the solutions proposed by different authors. Special attention is paid to the control strategies when combining SCs with other technologies, such as batteries. As a summary, some conclusions are collected drawn from the publications analyzed, evaluating the aspects in which it is necessary to conduct further research in order to facilitate the integration of EDLC technology.

Energy consumption optimization for AC drives position control

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Branislav Ftorek ◽  
Milan Saga ◽  
Pavol Orsansky ◽  
Jan Vittek ◽  
Peter Butko
Keyword(s):  
Control System ◽  
Energy Saving ◽  
Energy Savings ◽  
Position Control ◽  
Control Strategies ◽  
Content Type ◽  
Ac Drives ◽  
Energy Demands ◽  
Wide Range ◽  
Energy Consumption Optimization

Purpose The main purpose of this paper is to evaluate the two energy saving position control strategies for AC drives valid for a wide range of boundary conditions including an analysis of their energy expenses. Design/methodology/approach For energy demands analysis, the optimal energy control based on mechanical and electrical losses minimization is compared with the near-optimal one based on symmetrical trapezoidal speed profile. Both control strategies respect prescribed maneuver time and define acceleration profile for preplanned rest-to-rest maneuver. Findings Presented simulations confirm lower total energy expenditures of energy optimal control if compared with near-optimal one, but the differences are only small due to the fact that two energy saving strategies are compared. Research limitations/implications Developed overall control system consisting of energy saving profile generator, pre-compensator and position control system respecting principles of field-oriented control is capable to track precomputed state variables precisely. Practical implications Energy demands of both control strategies are verified and compared to simulations and preliminary experiments. The possibilities of energy savings were confirmed for both control strategies. Originality/value Experimental verification of designed control structure is sufficiently promising and confirmed assumed energy savings.

A Comprehensive Review on Reconfigurable Drones: Classification, Characteristics, Design and Control Technologies

2021 ◽  
pp. 1-27
Author(s):  
Saddam Hocine Derrouaoui ◽  
Yasser Bouzid ◽  
Mohamed Guiatni ◽  
Islam Dib
Keyword(s):  
Fault Tolerant ◽  
Control Strategies ◽  
Cluttered Environments ◽  
Viable Solution ◽  
Promising Solution ◽  
Design Characteristics ◽  
And Performance ◽  
Control Technologies ◽  
And Control ◽  
Near Future

Recently, reconfigurable drones have gained particular attention in the field of automation and flying robots. Unlike the conventional drones, they are characterized by a variable mechanical structure in flight, geometric adaptability, aerial reconfiguration, high number of actuators and control inputs, and variable mathematical model. In addition, they are exploited to flight in more cluttered environments, avoid collisions with obstacles, transport and grab objects, cross narrow and small spaces, decrease different aerial damages, optimize the consumed energy, and improve agility and maneuverability in flight. Moreover, these new drones are considered as a viable solution to provide them with specific and additional functionalities. They are a promising solution in the near future, since they allow increasing considerably the capabilities and performance of classical drones in terms of multi-functionalities, geometric adaptation, design characteristics, consumed energy, control, maneuverability, agility, efficiency, obstacles avoidance, and fault tolerant control. This paper explores very interesting and recent research works, which include the classification, the main characteristics, the various applications, and the existing designs of this particular class of drones. Besides, an in-depth review of the applied control strategies will be presented. The links of the videos displaying the results of these researches will be also shown. A comparative study between the different types of flying vehicles will be established. Finally, several new challenges and future directions for reconfigurable drones will be discussed.

Potassium Phosphite Mixed with Other Fungicides Reduces Yield Loss to Downy Mildew on Collard

2010 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Anthony P. Keinath
Keyword(s):  
Downy Mildew ◽  
Yield Loss ◽  
Control Strategies ◽  
Southeastern United States ◽  
Production Costs ◽  
Water Control ◽  
Economic Return ◽  
Potassium Phosphite ◽  
Full Rate ◽  
Reduced Rate

Downy mildew of collard occurs frequently in the southeastern United States, and fungicides have become an essential part of economical control strategies for the disease. Fungicides were evaluated in 2007 and 2008 either alone or combined with a reduced rate (2 pt/acre) of potassium phosphite. Two formulations of potassium phosphite also were tested alone at the full rate (4 pt/acre). Presidio, Presidio plus Pro-Phyt (2007) or K-Phite (2008), K-Phite, Amistar plus ProPhyt, and Aliette reduced downy mildew severity at the final rating and also reduced AUDPC over the two years. Presidio plus potassium phosphite and Amistar plus ProPhyt increased the weight of healthy leaves and stems over the water control and also increased economic return calculated after fungicide and other production costs were subtracted from the crop value. The yields with Ranman, Sonata, and Presidio applied in combination with potassium phosphite were 16% greater than with the fungicides applied alone. Potassium phosphite may be useful in a tank-mix with other fungicides applied to collard to prevent yield loss to downy mildew. Accepted for publication 7 July 2010. Published 23 August 2010.

scholarly journals Design and Experimental Evaluation of a Robust Position Controller for an Electrohydrostatic Actuator Using Adaptive Antiwindup Sliding Mode Scheme

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Ji Min Lee ◽  
Sung Hwan Park ◽  
Jong Shik Kim
Keyword(s):  
Control Systems ◽  
Pid Controller ◽  
Position Control ◽  
Sliding Mode ◽  
System Modeling ◽  
Modeling Error ◽  
Load Disturbance ◽  
Control Scheme ◽  
Position Controller ◽  
System Uncertainties

A robust control scheme is proposed for the position control of the electrohydrostatic actuator (EHA) when considering hardware saturation, load disturbance, and lumped system uncertainties and nonlinearities. To reduce overshoot due to a saturation of electric motor and to realize robustness against load disturbance and lumped system uncertainties such as varying parameters and modeling error, this paper proposes an adaptive antiwindup PID sliding mode scheme as a robust position controller for the EHA system. An optimal PID controller and an optimal anti-windup PID controller are also designed to compare control performance. An EHA prototype is developed, carrying out system modeling and parameter identification in designing the position controller. The simply identified linear model serves as the basis for the design of the position controllers, while the robustness of the control systems is compared by experiments. The adaptive anti-windup PID sliding mode controller has been found to have the desired performance and become robust against hardware saturation, load disturbance, and lumped system uncertainties and nonlinearities.

scholarly journals Novel Design and Position Control Strategy of a Soft Robot Arm

Robotics ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 72 ◽  
Author(s):  
Alaa Al-Ibadi ◽  
Samia Nefti-Meziani ◽  
Steve Davis ◽  
Theo Theodoridis
Keyword(s):  
Position Control ◽  
Control Strategies ◽  
Tensile Force ◽  
Compressive Force ◽  
Soft Robot ◽  
Robot Arm ◽  
Bending Actuator ◽  
Muscle Actuators ◽  
Novel Design ◽  
Bending Behaviour

This article presents a novel design of a continuum arm, which has the ability to extend and bend efficiently. Numerous designs and experiments have been done to different dimensions on both types of McKibben pneumatic muscle actuators (PMA) in order to study their performances. The contraction and extension behaviour have been illustrated with single contractor actuators and single extensor actuators, respectively. The tensile force for the contractor actuator and the compressive force for the extensor PMA are thoroughly explained and compared. Furthermore, the bending behaviour has been explained for a single extensor PMA, multi extensor actuators and multi contractor actuators. A two-section continuum arm has been implemented from both types of actuators to achieve multiple operations. Then, a novel construction is proposed to achieve efficient bending behaviour of a single contraction PMA. This novel design of a bending-actuator has been used to modify the presented continuum arm. Two different position control strategies are presented, arising from the results of the modified soft robot arm experiment. A cascaded position control is applied to control the position of the end effector of the soft arm at no load by efficiently controlling the pressure of all the actuators in the continuum arm. A new algorithm is then proposed by distributing the x, y and z-axis to the actuators and applying an effective closed-loop position control to the proposed arm at different load conditions.

scholarly journals A Joint-space Position Control-based Approach to Haptic Rendering of Stiff Objects using Gain Scheduling

2021 ◽  
Vol 103 (3) ◽  
Author(s):  
Yang Wang ◽  
Lei Feng ◽  
Kjell Andersson
Keyword(s):  
Simulation Model ◽  
Position Control ◽  
Gain Scheduling ◽  
Joint Space ◽  
Haptic Rendering ◽  
Smooth Transition ◽  
Position Controller ◽  
Detailed Simulation ◽  
Stability Issues ◽  
Computing Models

AbstractHaptic rendering often deals with interactions between stiff objects. A traditional way of force computing models the interaction using a spring-damper system, which suffers from stability issues when the desired stiffness is high. Instead of computing a force, this paper continues to explore shifting the focus to rendering an interaction with no penetration, which can be accomplished by using a position controller in the joint space using the encoders as feedback directly. In order to make this approach easily adaptable to any device, an alternative way to model the dynamics of the device is also presented, which is to linearize a detailed simulation model. As a family of linearized models is used to approximate the full dynamic model of the system, it is important to have a smooth transition between multiple sets of controller gains generated based on these models. Gain scheduling is introduced to improve the performance in certain areas and a comparison among three controllers is conducted in a simulation setup.

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