scholarly journals Realization of active metamaterials with odd micropolar elasticity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yangyang Chen ◽  
Xiaopeng Li ◽  
Colin Scheibner ◽  
Vincenzo Vitelli ◽  
Guoliang Huang
Keyword(s):  
Electrical Energy ◽  
Emergent Properties ◽  
Micropolar Elasticity ◽  
Feed Forward ◽  
Control Loops ◽  
Feed Forward Control ◽  
Bending Modulus ◽  
Active Metamaterials ◽  
Energy Conserving ◽  
And Control

AbstractMaterials made from active, living, or robotic components can display emergent properties arising from local sensing and computation. Here, we realize a freestanding active metabeam with piezoelectric elements and electronic feed-forward control that gives rise to an odd micropolar elasticity absent in energy-conserving media. The non-reciprocal odd modulus enables bending and shearing cycles that convert electrical energy into mechanical work, and vice versa. The sign of this elastic modulus is linked to a non-Hermitian topological index that determines the localization of vibrational modes to sample boundaries. At finite frequency, we can also tune the phase angle of the active modulus to produce a direction-dependent bending modulus and control non-Hermitian vibrational properties. Our continuum approach, built on symmetries and conservation laws, could be exploited to design others systems such as synthetic biofilaments and membranes with feed-forward control loops.

DECAFF: Experimental Study on Human Haptic Perception

2000 ◽  
Author(s):  
Scott L. Springer ◽  
Nicola J. Ferrier
Keyword(s):  
Interface Design ◽  
Haptic Perception ◽  
Human Perception ◽  
Initial Contact ◽  
Haptic Interfaces ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Contact Distance ◽  
Traditional Approaches ◽  
And Control

Abstract DECAFF is a method for design and control of haptic interfaces that utilizes a DE-Coupled Actuator and Feed-Forward control. In this paper results of an experimental investigation are presented that quantify improved human haptic perception while using the DECAFF system, compared to the traditional haptic interface design and control systems. Perception improvements include the increased stability for rigid surfaces and increased ability of subjects to accurately identify initial contact with virtual surface boundaries. Traditional haptic interfaces employ an actuator directly coupled to the human operator that provides a force proportional to wall penetration distance and velocity. The DECAFF paradigm for design and control of haptic displays utilizes a de-coupled actuator and pre-contact distance sensing as a feed forward control term to improve stability and response performance. A human perception experiment has been performed that compares the touch sensation of the subjects for both the DECAFF system and traditional approaches to haptic display. In the human factors study the quality of rigid body display is evaluated in addition to the sensitivity of touch experienced by the subjects while making initial contact with virtual surfaces.

The Research of Re-Winder Bottom Roller Feed-Forward Control Tactic

2011 ◽  
Vol 225-226 ◽  
pp. 146-149
Author(s):  
Jing Wen Chen ◽  
Xiao Ping Sun
Keyword(s):  
Feedback Control ◽  
Production Process ◽  
System Response ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Loop Feedback ◽  
Bottom Roller ◽  
Working Procedure ◽  
And Control

As the last working procedure in the paper production process, re-winder control technology is crucial to the quality of finished paper scroll. To obtain the paper scroll with inner tight and outer loose, the control of bottom rollers must satisfy the double closed-loop feedback control with torque difference. While the feedback control exists time-delay and may cause the slowness of system response. Here on the basis of re-winder production process and control requirements, a novel feed-forward control tactics is proposed to combine with feedback control. According to the compensation of feed-forward control, rapid system response is obtained and system performance is improved. And corresponding simulation shows the validity and feasibility of the feed-forward control tactics.

Trajectory Control of a Tethered Underwater Robot System

2018 ◽  
Author(s):  
Jiaming Wu ◽  
Dongjun Chen ◽  
Ying Xu ◽  
Yuqing Chen ◽  
Lihua Lu
Keyword(s):  
Pid Control ◽  
Control Algorithm ◽  
Trajectory Control ◽  
Underwater Robot ◽  
Robot System ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Robot Trajectory ◽  
Umbilical Cable ◽  
And Control

A three-dimensional hydrodynamic and control model to simulate tethered underwater robot system is proposed. The fluid motion around the moving robot main body with running control ducted propellers is governed by Navier-Stokes equations, and multiple sliding mesh technique is applied to solve the governing equations. The governing equation of umbilical cable connected to the robot is based on the Ablow and Schechter method. The six-degrees-of-freedom equations of motion for underwater vehicle simulations proposed by Gertler and Hargen are adopted to estimate the hydrodynamic performance of the underwater robot. In the model, the feed-forward control algorithm is applied to adjust the length of the umbilical cable according to the robot trajectory control target, the incremental PID control algorithm is adopt to regulate the rotating speeds of the ducted propellers producing appropriate thrusts for the robot control. With the proposed hydrodynamic and control model, hydrodynamic behaviors of the robot under definite trajectory control manipulations are observed numerically. The numerical results of robot trajectory control simulations indicate that the feed-forward control algorithm for adjusting the length of the umbilical cable, and the incremental PID control algorithm for regulating the rotating speeds of the propellers are feasible and effective, the adjusting the length of the umbilical cable with feed-forward control technique is largely responsible for the vertical trajectory control to the robot, while regulating the rotating speeds of the propellers by the PID control algorithm play a leading role in the horizontal trajectory manipulation, the deviation between the designated trajectory and the control one at each time step is acceptable.

Using advanced control, post-denitrification and equalisation to improve the performance of a submerged filter

2000 ◽  
Vol 41 (4-5) ◽  
pp. 177-184 ◽  
Author(s):  
K.H. Sørensen ◽  
D. Thornberg ◽  
K.F. Janning
Keyword(s):  
Energy Consumption ◽  
Total N ◽  
Control Loops ◽  
Effluent Quality ◽  
Advanced Control ◽  
Before And After ◽  
And Control ◽  
Side Flow ◽  
Configuration Control ◽  
Control Post

In 1998, the capacity of the BIOSTYR® submerged biofilter at Nyborg WWTP was extended from 48,000 PE to 60,000 PE including advanced sensor based control, post-denitrification in BIOSTYR® and equalization of side flows. The existing configuration with 8 BIOSTYR® DN/N cells is based on pre-denitrification and an internal recirculation of 600–800%. The extended plant comprises 7 BIOSTYR® DN/N cells with 50–225% recirculation followed by 3 BIOSTYR DN cells for post-denitrification. The advanced control loops include blower control, control of the number of active cells (stand-by), automatic switch to high load configuration, control of the side flow equalization, control of the internal recirculation and control of the external carbon source dosing. In this paper, the achieved improvements are documented by comparing influent and effluent data, methanol and energy consumption from comparable periods before and after the extension. Although the nitrogen load to the plant was increased by 20% after the extension, the effluent quality has improved significantly with a reduction of Total-N from 7–8 mg/l to 3–4 mg/l. Simultaneously, the methanol consumption has been reduced by more than 50% per kg removed nitrogen. The energy consumption remained constant although the nitrogen load was increased by 20% and the inflow by 80%.

Learning and control

2018 ◽  
Author(s):  
Ivan Herreros
Keyword(s):  
Machine Learning ◽  
Reinforcement Learning ◽  
Brain Function ◽  
Control Strategies ◽  
Learning Problems ◽  
Animal Learning ◽  
Feed Forward Control ◽  
Machine Learning Applications ◽  
And Control

This chapter discusses basic concepts from control theory and machine learning to facilitate a formal understanding of animal learning and motor control. It first distinguishes between feedback and feed-forward control strategies, and later introduces the classification of machine learning applications into supervised, unsupervised, and reinforcement learning problems. Next, it links these concepts with their counterparts in the domain of the psychology of animal learning, highlighting the analogies between supervised learning and classical conditioning, reinforcement learning and operant conditioning, and between unsupervised and perceptual learning. Additionally, it interprets innate and acquired actions from the standpoint of feedback vs anticipatory and adaptive control. Finally, it argues how this framework of translating knowledge between formal and biological disciplines can serve us to not only structure and advance our understanding of brain function but also enrich engineering solutions at the level of robot learning and control with insights coming from biology.

scholarly journals Model-based feed-forward control for time-varying systems with an example for SRF cavities

2020 ◽  
Vol 53 (2) ◽  
pp. 1331-1336
Author(s):  
Sven Pfeiffer ◽  
Annika Eichler ◽  
Holger Schlarb
Keyword(s):  
Time Varying ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Model Based ◽  
Time Varying Systems ◽  
Srf Cavities

Flatness Feed-Forward Control Model Based on Neural Networks

2014 ◽  
Vol 989-994 ◽  
pp. 3386-3389
Author(s):  
Zhu Wen Yan ◽  
Hen An Bu ◽  
Dian Hua Zhang ◽  
Jie Sun
Keyword(s):  
Neural Networks ◽  
Rolling Mill ◽  
Rolling Force ◽  
Work Roll ◽  
Control Model ◽  
Good Effect ◽  
Feed Forward ◽  
Force Fluctuations ◽  
Feed Forward Control ◽  
Roll Bending

The influence on the shape of the strip from rolling force fluctuations has been analyzed. The combination of intermediate roll bending and work roll bending has been adopted. The principle of rolling force feed-forward control has been analyzed. The feed-forward control model has been established on the basis of neural networks. The model has been successfully applied to a rolling mill and a good effect has been achieved.

scholarly journals Feed-forward control of preshaping in the rat is mediated by the corticospinal tract

2010 ◽  
Vol 32 (10) ◽  
pp. 1678-1685 ◽  
Author(s):  
Jason B. Carmel ◽  
Sangsoo Kim ◽  
Marcel Brus-Ramer ◽  
John H. Martin
Keyword(s):  
Corticospinal Tract ◽  
Feed Forward ◽  
Feed Forward Control
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