Design and Analysis of a Multimodal Grasper Having Shape Conformity and Within-Hand Manipulation With Adjustable Contact Forces

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Nagamanikandan Govindan ◽  
Asokan Thondiyath
Keyword(s):  
Control Strategies ◽  
Low Cost ◽  
Active Surface ◽  
Force Sensor ◽  
Contact Forces ◽  
Geometrical Shape ◽  
Planning And Control ◽  
Control Scheme ◽  
And Control ◽  
Compact Mechanism

Abstract This paper presents the design, analysis, and testing of a novel multimodal grasper having the capabilities of shape conformation, within-hand manipulation, and a built-in compact mechanism to vary the forces at the contact surface. The proposed grasper has two important qualities: versatility and less complexity. The former refers to the ability to grasp a range of objects having different geometrical shape, size, and payload and perform in-hand manipulations such as rolling and sliding, and the latter refers to the uncomplicated design, and ease of planning and control strategies. Increasing the number of functions performed by the grasper to adapt to a variety of tasks in structured and unstructured environments without increasing the mechanical complexity is the main interest of this research. The proposed grasper consists of two hybrid jaws having a rigid inner structure encompassed by a flexible, active gripping surface. The flexibility of the active surface has been exploited to achieve shape conformation, and the same has been utilized with a compact mechanism, introduced in the jaws, to vary the contact forces while grasping and manipulating an object. Simple and scalable structure, compactness, low cost, and simple control scheme are the main features of the proposed design. Detailed kinematic and static analysis are presented to show the capability of the grasper to adjust and estimate the contact forces without using a force sensor. Experiments are conducted on the fabricated prototype to validate the different modes of operation and to evaluate the advantages of the proposed concept.

scholarly journals Soft Sensors for Biomass Monitoring during Low Cost Cellulase Production

2021 ◽  
Author(s):  
Chitra Murugan
Keyword(s):  
Fermentation Process ◽  
Control Strategies ◽  
Low Cost ◽  
Cellulase Production ◽  
Monitoring And Control ◽  
Soft Sensors ◽  
Control Scheme ◽  
Solid Substrates ◽  
Biomass Monitoring ◽  
And Control

Low cost cellulase production has become a major challenge in recent years. The major hurdle in the production of biofuel and other products from biomass is the lack of efficient economically feasible cellulase. This can be achieved by proper monitoring and control of bioprocess. In order to implement any control scheme, the accurate representation of the system in the form of a model is necessary. There are many challenges associated with modeling the fermentation process such as inherent nonlinear dynamic behavior, complexity of process due to co-existence of viable and nonviable cells, presence of solid substrates, etc. Toward the achievement of this goal, researchers have been developing new techniques that can be used to monitor the process online and at-line. These newer techniques have paved the way for designing better control strategies that can be integrated with quality by design (QbD) and process analytic technology (PAT).

scholarly journals Semi-Active Magnetic Levitation System for Education

2021 ◽  
Vol 11 (12) ◽  
pp. 5330
Author(s):  
Gisela Pujol-Vázquez ◽  
Alessandro N. Vargas ◽  
Saleh Mobayen ◽  
Leonardo Acho
Keyword(s):  
Pid Control ◽  
Magnetic Levitation ◽  
Low Cost ◽  
Control Scheme ◽  
Hands On ◽  
Levitation System ◽  
Magnetic Levitation System ◽  
And Control ◽  
Active Control Strategy ◽  
Cost Components

This paper describes how to construct a low-cost magnetic levitation system (MagLev). The MagLev has been intensively used in engineering education, allowing instructors and students to learn through hands-on experiences of essential concepts, such as electronics, electromagnetism, and control systems. Built from scratch, the MagLev depends only on simple, low-cost components readily available on the market. In addition to showing how to construct the MagLev, this paper presents a semi-active control strategy that seems novel when applied to the MagLev. Experiments performed in the laboratory provide comparisons of the proposed control scheme with the classical PID control. The corresponding real-time experiments illustrate both the effectiveness of the approach and the potential of the MagLev for education.

On the Use of Actively Controlled Auxiliary Bearings in Magnetic Bearing Systems

2008 ◽  
Author(s):  
Iain S. Cade ◽  
M. Necip Sahinkaya ◽  
Clifford R. Burrows ◽  
Patrick S. Keogh
Keyword(s):  
Controller Design ◽  
Control Strategies ◽  
Frictional Heating ◽  
Magnetic Bearing ◽  
Contact Forces ◽  
Active Magnetic Bearing ◽  
Physical Limit ◽  
Drop Tests ◽  
Auxiliary Bearing ◽  
And Control

Auxiliary bearings are used to prevent rotor/stator contact in active magnetic bearing systems. They are sacrificial components providing a physical limit on the rotor displacement. During rotor/auxiliary bearing contact significant forces normal to the contact zone may occur. Furthermore, rotor slip and rub can lead to localized frictional heating. Linear control strategies may also become ineffective or induce instability due to changes in rotordynamic characteristics during contact periods. This work considers the concept of using actively controlled auxiliary bearings in magnetic bearing systems. Auxiliary bearing controller design is focused on attenuating bearing vibration resulting from contact and reducing the contact forces. Controller optimization is based on the H∞ norm with appropriate weighting functions applied to the error and control signals. The controller is assessed using a simulated rotor/magnetic bearing system. Comparison of the performance of an actively controlled auxiliary bearing is made with that of a resiliently mounted auxiliary bearing. Rotor drop tests, repeated contact tests, and sudden rotor unbalance resulting in trapped contact modes, are considered.

scholarly journals Human-Following Motion Planning and Control Scheme for Collaborative Robots Based on Human Motion Prediction

2021 ◽  
Author(s):  
Fahad Iqbal Khawaja ◽  
Akira Kanazawa ◽  
Jun Kinugawa ◽  
Kazuhiro Kosuge
Keyword(s):  
Motion Planning ◽  
Human Motion ◽  
Human Robot Interaction ◽  
Collaborative Robots ◽  
Sensing System ◽  
Planning And Control ◽  
Control Scheme ◽  
Active Research ◽  
And Control ◽  
Collaborative Robot

Human-Robot Interaction (HRI) for collaborative robots has become an active research topic recently. Collaborative robots assist the human workers in their tasks and improve their efficiency. But the worker should also feel safe and comfortable while interacting with the robot. In this paper, we propose a human-following motion planning and control scheme for a collaborative robot which supplies the necessary parts and tools to a worker in an assembly process in a factory. In our proposed scheme, a 3-D sensing system is employed to measure the skeletal data of the worker. At each sampling time of the sensing system, an optimal delivery position is estimated using the real-time worker data. At the same time, the future positions of the worker are predicted as probabilistic distributions. A Model Predictive Control (MPC) based trajectory planner is used to calculate a robot trajectory that supplies the required parts and tools to the worker and follows the predicted future positions of the worker. We have installed our proposed scheme in a collaborative robot system with a 2-DOF planar manipulator. Experimental results show that the proposed scheme enables the robot to provide anytime assistance to a worker who is moving around in the workspace while ensuring the safety and comfort of the worker.

KW Level Wind Turbine Wind Tracking and Yaw System

2011 ◽  
Vol 148-149 ◽  
pp. 97-100
Author(s):  
Xu Gang Wang ◽  
Guang Qi Cao ◽  
Zhi Guang Guan ◽  
Zu Yu Zhao
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Fossil Fuels ◽  
Control Strategies ◽  
Low Cost ◽  
Control Program ◽  
Clean Energy ◽  
New Energy ◽  
Program Flow ◽  
And Control

Wind power is an important direction of new energy, which has no pollution, no consuming fossil fuels, and no producing waste, which is widely used at this stage of clean energy. The small stand alone wind power has been paid more and more attention due to its low cost, flexible installation, strong adaptability. This paper introduces the mechanical and electrical structure, which are used in KW level stand alone mode wind turbine automatically track and yaw system. The motion rules and control strategies of the tracking and yaw system are discussed and then the control program flow is provided. The PIC16F873 chip is used as controller for this part in this system. It can fully meet the design requirements, which will reduce costs and increase the system's control ability. This system can automatically track and yaw, according to the wind direction and wind power.

scholarly journals Simulative Assessment of Agent Based Production Planning and Control Strategies

Procedia CIRP ◽  
2016 ◽  
Vol 57 ◽  
pp. 439-444 ◽  
Author(s):  
Denis Kurle ◽  
Stefan Blume ◽  
Tobias Zurawski ◽  
Sebastian Thiede
Keyword(s):  
Production Planning ◽  
Control Strategies ◽  
Production Planning And Control ◽  
Agent Based ◽  
Planning And Control ◽  
And Control

scholarly journals Autonomous Deployment of Underwater Acoustic Monitoring Devices Using an Unmanned Aerial Vehicle: The Flying Hydrophone

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6064
Author(s):  
Daniel Babatunde ◽  
Simon Pomeroy ◽  
Paul Lepper ◽  
Ben Clark ◽  
Rebecca Walker
Keyword(s):  
Autonomous Navigation ◽  
Marine Mammals ◽  
Fourier Transforms ◽  
Low Cost ◽  
Acoustic Monitoring ◽  
Automatic Data ◽  
Underwater Acoustic ◽  
Planning And Control ◽  
The United Kingdom ◽  
And Control

Unmanned aerial vehicles (UAV) are increasingly becoming a popular tool in the observation and study of marine mammals. However, the potential capabilities of these vehicles regarding autonomous operations are not being fully exploited for passive underwater acoustic monitoring in marine mammal research. This article presents results from the development of a UAV system equipped with an underwater acoustic recorder aimed at assisting with the monitoring of harbour porpoises in Special Areas of Conservation in the United Kingdom. The UAV is capable of autonomous navigation, persistent landing, take-off and automatic data acquisition at specified waypoints. The system architecture that enables autonomous UAV flight including waypoint planning and control is described. A bespoke lightweight underwater acoustic recorder (named the PorpDAQ) capable of transmitting the results of fast Fourier transforms (FFT) applied to incoming signals from a hydrophone was also designed. The system’s operation is successfully validated with a combination of outdoor experiments and indoor simulations demonstrating different UAVs capable of autonomously navigating and landing at specific waypoints while recording data in an indoor tank. Results from the recorder suggest that lightweight, relatively low-cost systems can be used in place of heavier more expensive alternatives.

scholarly journals Reaching to inhibit a prepotent response: A wearable 3-axis accelerometer kinematic analysis

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254514
Author(s):  
Alessia Angeli ◽  
Irene Valori ◽  
Teresa Farroni ◽  
Gustavo Marfia
Keyword(s):  
Low Cost ◽  
Motor Planning ◽  
Cognitive Mechanisms ◽  
Dominant Response ◽  
Planning And Control ◽  
Prepotent Response ◽  
Human Movements ◽  
Kinematic Measures ◽  
And Control ◽  
Selection Of

The present work explores the distinctive contribution of motor planning and control to human reaching movements. In particular, the movements were triggered by the selection of a prepotent response (Dominant) or, instead, by the inhibition of the prepotent response, which required the selection of an alternative one (Non-dominant). To this end, we adapted a Go/No-Go task to investigate both the dominant and non-dominant movements of a cohort of 19 adults, utilizing kinematic measures to discriminate between the planning and control components of the two actions. In this experiment, a low-cost, easy to use, 3-axis wrist-worn accelerometer was put to good use to obtain raw acceleration data and to compute and break down its velocity components. The values obtained with this task indicate that with the inhibition of a prepotent response, the selection and execution of the alternative one yields both a longer reaction time and movement duration. Moreover, the peak velocity occurred later in time in the non-dominant response with respect to the dominant response, revealing that participants tended to indulge more in motor planning than in adjusting their movement along the way. Finally, comparing such results to the findings obtained by other means in the literature, we discuss the feasibility of an accelerometer-based analysis to disentangle distinctive cognitive mechanisms of human movements.

scholarly journals Nonlinear control of GTI for stabilizing future smart grids

2020 ◽  
Vol 11 (3) ◽  
pp. 1268
Author(s):  
Salam Ibrahim Khather
Keyword(s):  
Control Systems ◽  
Distributed Generation ◽  
Smart Grids ◽  
High Performance ◽  
Low Cost ◽  
Control Parameters ◽  
Leakage Currents ◽  
Control Techniques ◽  
Control Scheme ◽  
And Control

The most important components of the distributed generation frameworks is the GTIs which is an interface amidst the utility and the source of energy. The recent years have seen an increased interest in the design and usage of GTIs due to its smaller weight and size, low cost and higher efficiency. But the problem of leakage currents in the transformerless inverter that is dependant on its topology and control scheme needs to be looked into carefully. Also, the high performance of the GTI requires a stringent control and various control systems are being developed and applied to the GTIs. This paper reviews the various topologies that are classified based on the attributes of the leakage current and the method of decoupling. Further it reviews and compares the different control techniques applied to the GTIs with respect to the frame of reference, controller, modulation technique and the control parameters considered.

scholarly journals An Advanced Guidance and Control System for an Unmanned Vessel with Azimuthal Thrusters

2018 ◽  
Author(s):  
M Bibuli ◽  
Ga Bruzzone ◽  
Gi Bruzzone ◽  
M Caccia ◽  
G Camporeale ◽  
...  
Keyword(s):  
Autonomous Navigation ◽  
Control Strategies ◽  
Vertical Axis ◽  
Control Loop ◽  
Guidance And Control ◽  
Marine Vehicles ◽  
Regulation Scheme ◽  
Control Scheme ◽  
Constrained Environments ◽  
And Control

The proposed paper presents the design and development of the combined guidance and control strategies for the autonomous navigation of an unmanned vessel characterized by azimuth-based thrust architecture. Autonomous Marine Vehicles (AMVs) are consolidates technological tools commonly employed for different tasks such as exploration, sampling and intervention. With the final aim of autonomous shipping, the capabilities of AMVs have to be migrated and adapted towards the reliable and safe control of commercial-like unmanned vessel, that are taking place thanks to a number of technological research projects. The employment of new concept hulls and thrust configurations, as for instance Small Waterplane Area Twin Hull (SWATH) combined with Azimuthal propulsion (common propeller-based thruster with the capability of 360◦ rotation around the vertical axis), requires robust guidance techniques to provide precise and reliable motion control during navigation. The paper proposes a dual-loop guidance and control scheme able to provide advanced navigation capabilities. In particular, the inner control loop, devoted to the actuation of the azimuthal thrusters, allows the tracking of reference course angle (namely the autopilot). Such a control loop is characterized by a modified PID regulation scheme, where a novel adaptive derivative component is inserted in order to improve the convergence curve towards the required course reference. The outer guidance loop, based on Lyapunov/virtual-target approach, allows the vessel to track generic desired paths, thus enhancing the autonomous navigation capabilities also in constrained environments. The paper will provide a deep design and analysis approach for the developed techniques, as well as simulation results of the combined guidance and control scheme, proving the reliability of the proposed approach in different operative conditions. Experimental results will be provided, depending on the availability of the actual autonomous vessel (currently under final development/test phases and related to the specific project activities). 

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