scholarly journals Attainable Moment Set Optimization to Support Configuration Design: A Required Moment Set Based Approach

2021 ◽  
Vol 11 (8) ◽  
pp. 3685
Author(s):  
Jiannan Zhang ◽  
Max Söpper ◽  
Florian Holzapfel
Keyword(s):  
Disturbance Rejection ◽  
Convex Set ◽  
Design Parameters ◽  
Speed Up ◽  
Optimization Methodology ◽  
The Moment ◽  
And Control ◽  
Moment Set ◽  
Control Surfaces ◽  
Mission Profile

In this paper, we discuss an attainable moment set (AMS) optimization methodology considering a system’s required moment set (RMS). The AMS describes the achievable moments from a system, given its input limits. An RMS, like an AMS, is a convex set in the moment space, describing the required moments for a system to meet the designed mission profile and disturbance rejection requirements. Given the configuration of a system, its mission requirements, and the derived RMS, the proposed optimization maximizes coverage of the AMS onto the RMS, thus ensuring the system possesses the guaranteed controllability to fulfill its required missions from a design level. To achieve this goal, the variables to optimize are chosen as effector settings, such as the installation position and angle of propellers and control surfaces, which effectively change the AMS without a vast impact on major design parameters, such as mass and moment of inertia. Since the optimization includes massive geometry operations of rays intersecting polyhedron, an efficient intersection solver is proposed to speed up the optimization process. The described method is applied to an electric-vertical-take-of-landing vehicle (eVTOL) with eight hover propellers, which delivers a highly improved coverage of the RMS compared to its initial design.

Automated reverse engineering control system model

2020 ◽  
pp. 39-43
Author(s):  
A. V. Vinnichenko ◽  
S. A. Nazarevich ◽  
I. R. Karpova
Keyword(s):  
Control System ◽  
Reverse Engineering ◽  
Flaw Detection ◽  
Production Capacity ◽  
Speed Up ◽  
Environmental Requirements ◽  
Traditional Technologies ◽  
The Moment ◽  
Control System Model ◽  
Favorable Conditions

The article deals with the task of simplifying the reverse design process by implementing three-point 3D scanning, which allows you to speed up the technological stages of reverse design to the moment of product manufacture, as well as simplify the procedure for defecating finished products and create favorable conditions for the implementation of the principles of unification. The model of the control system in this article refers to the structuring of elements of the technological organization of the process of creating 3D prototyping of existing copies created by the use of reverse engineering. For this purpose, the problems of traditional technologies that do not allow timely coping with changes in the technical system under the influence of in accordance with the requirements of regulatory documents and environmental requirements were considered. We also analyzed not only the principles of operation of traditional technologies, but also the zone of reverse engineering, which allows you to achieve an increased level of production capacity by identifying a group of key defects based on the process of flaw detection and statistical analysis.

scholarly journals Design, modeling, and demonstration of a new dual-mode back-assist exosuit with extension mechanism

2021 ◽  
Vol 2 ◽  
Author(s):  
Erik P. Lamers ◽  
Karl E. Zelik
Keyword(s):  
Biomechanical Model ◽  
Mode Switching ◽  
Design Parameters ◽  
Dual Mode ◽  
Extension Mechanism ◽  
Body Forces ◽  
Low Profile ◽  
Military Healthcare ◽  
The Moment ◽  
Practical Factors

Abstract Occupational exoskeletons and exosuits have been shown to reduce muscle demands and fatigue for physical tasks relevant to a variety of industries (e.g., logistics, construction, manufacturing, military, healthcare). However, adoption of these devices into the workforce has been slowed by practical factors related to comfort, form-factor, weight, and not interfering with movement or posture. We previously introduced a low-profile, dual-mode exosuit comprised of textile and elastic materials to address these adoption barriers. Here we build upon this prior work by introducing an extension mechanism that increases the moment arm of the exosuit while in engaged mode, then collapses in disengaged mode to retain key benefits related to being lightweight, low-profile, and unobstructive. Here we demonstrate both analytically and empirically how this extensible exosuit concept can (a) reduce device-to-body forces (which can improve comfort for some users and situations), or (b) increase the magnitude of torque assistance about the low back (which may be valuable for heavy-lifting jobs) without increasing shoulder or leg forces relative to the prior form-fitting exosuit. We also introduce a novel mode-switching mechanism, as well as a human-exosuit biomechanical model to elucidate how individual design parameters affect exosuit assistance torque and device-to-body forces. The proof-of-concept prototype, case study, and modeling work provide a foundation for understanding and implementing extensible exosuits for a broad range of applications. We envision promising opportunities to apply this new dual-mode extensible exosuit concept to assist heavy-lifting, to further enhance user comfort, and to address the unique needs of last-mile and other delivery workers.

Automated sequencing batch bioreactor under extreme peaks of 4-chlorophenol

2003 ◽  
Vol 47 (10) ◽  
pp. 175-181 ◽  
Author(s):  
G. Buitrón ◽  
M.-E. Schoeb ◽  
J. Moreno
Keyword(s):  
Dissolved Oxygen ◽  
Metabolic Activity ◽  
Automated System ◽  
Stable Operation ◽  
High Concentration ◽  
Batch Bioreactor ◽  
On Line ◽  
The Moment ◽  
And Control ◽  
System Operating

The operation of a sequencing batch bioreactor is evaluated when high concentration peaks of a toxic compound (4-chlorophenol, 4CP) are introduced into the reactor. A control strategy based on the dissolved oxygen concentration, measured on line, is utilized. To detect the end of the reaction period, the automated system search for the moment when the dissolved oxygen has passed by a minimum, as a consequence of the metabolic activity of the microorganisms and right after to a maximum due to the saturation of the water (similar to the self-cycling fermentation, SCF, strategy). The dissolved oxygen signal was sent to a personal computer via data acquisition and control using MATLAB and the SIMULINK package. The system operating under the automated strategy presented a stable operation when the acclimated microorganisms (to an initial concentration of 350 mg 4CP/L), were exposed to a punctual concentration peaks of 600 mg 4CP/L. The 4CP concentrations peaks superior or equals to 1,050 mg/L only disturbed the system from a short to a medium term (one month). The 1,400 mg/L peak caused a shutdown in the metabolic activity of the microorganisms that led to the reactor failure. The biomass acclimated with the SCF strategy can partially support the variations of the toxic influent since, at the moment in which the influent become inhibitory, there is a failure of the system.

Momentum exchange impact damper design methodology for object-wall-collision problems

2017 ◽  
Vol 24 (14) ◽  
pp. 3206-3218
Author(s):  
Yohei Kushida ◽  
Hiroaki Umehara ◽  
Susumu Hara ◽  
Keisuke Yamada
Keyword(s):  
Optimal Design ◽  
Design Methodology ◽  
Design Parameters ◽  
Momentum Exchange ◽  
Impact Damper ◽  
One Dimensional ◽  
Practical Design ◽  
Wall Collision ◽  
Damper Design ◽  
And Control

Momentum exchange impact dampers (MEIDs) were proposed to control the shock responses of mechanical structures. They were applied to reduce floor shock vibrations and control lunar/planetary exploration spacecraft landings. MEIDs are required to control an object’s velocity and displacement, especially for applications involving spacecraft landing. Previous studies verified numerous MEID performances through various types of simulations and experiments. However, previous studies discussing the optimal design methodology for MEIDs are limited. This study explicitly derived the optimal design parameters of MEIDs, which control the controlled object’s displacement and velocity to zero in one-dimensional motion. In addition, the study derived sub-optimal design parameters to control the controlled object’s velocity within a reasonable approximation to derive a practical design methodology for MEIDs. The derived sub-optimal design methodology could also be applied to MEIDs in two-dimensional motion. Furthermore, simulations conducted in the study verified the performances of MEIDs with optimal/sub-optimal design parameters.

Design Optimisation Strategies for a Hydraulic Hybrid Wheel Loader

2018 ◽  
Author(s):  
Karl Uebel ◽  
Henrique Raduenz ◽  
Petter Krus ◽  
Victor Juliano de Negri
Keyword(s):  
Energy Management ◽  
Design Parameters ◽  
Linear Component ◽  
Concept Design ◽  
Energy Management Strategy ◽  
Design Optimisation ◽  
Hydraulic Hybrid ◽  
Deterministic Dynamic ◽  
Control Optimisation ◽  
And Control

This paper deals with design optimisation of hydraulic hybrid drivelines during early concept design phases. To set the design parameters of a hybrid driveline such as gear ratios, pump/motor displacements and size of energy storage, the energy management of the hybrid machine needs to be considered as well. This is problematic since a nested design and control optimisation normally requires substantial computer power and is time-consuming. Few previous studies have treated combined design and control optimisation of hydraulic hybrid vehicles using detailed, non-linear component driveline models. Furthermore, previously proposed design optimisation methods for on-road vehicles are not suitable for heavy off-road machines operating in short repetitive cycles with high transient power output. The paper demonstrates and compares different optimisation approaches for design and control optimisation combining deterministic dynamic programming and non-gradient based numerical optimisation. The results show that a simple rule-based energy management strategy can be sufficient to find the optimal hardware design even though non-optimal control laws are used.

scholarly journals Body Flexibility Enhances Maneuverability in the World’s Largest Predator

2018 ◽  
Vol 59 (1) ◽  
pp. 48-60 ◽  
Author(s):  
P S Segre ◽  
D E Cade ◽  
J Calambokidis ◽  
F E Fish ◽  
A S Friedlaender ◽  
...  
Keyword(s):  
Open Ocean ◽  
The Body ◽  
Long Distance ◽  
Active Surfaces ◽  
Aquatic Locomotion ◽  
And Performance ◽  
And Control ◽  
Blue Whales ◽  
Control Surfaces ◽  
Complex Trajectories

Abstract Blue whales are often characterized as highly stable, open-ocean swimmers who sacrifice maneuverability for long-distance cruising performance. However, recent studies have revealed that blue whales actually exhibit surprisingly complex underwater behaviors, yet little is known about the performance and control of these maneuvers. Here, we use multi-sensor biologgers equipped with cameras to quantify the locomotor dynamics and the movement of the control surfaces used by foraging blue whales. Our results revealed that simple maneuvers (rolls, turns, and pitch changes) are performed using distinct combinations of control and power provided by the flippers, the flukes, and bending of the body, while complex trajectories are structured by combining sequences of simple maneuvers. Furthermore, blue whales improve their turning performance by using complex banked turns to take advantage of their substantial dorso-ventral flexibility. These results illustrate the important role body flexibility plays in enhancing control and performance of maneuvers, even in the largest of animals. The use of the body to supplement the performance of the hydrodynamically active surfaces may represent a new mechanism in the control of aquatic locomotion.

Design and Analysis of Reduced Degree of Freedom Modular Snake Robot

2017 ◽  
Author(s):  
Peter Racioppo ◽  
Wael Saab ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Three Dimensional ◽  
Cross Sectional ◽  
Design Synthesis ◽  
Snake Robot ◽  
Routing Schemes ◽  
Revolute Joints ◽  
Modular Units ◽  
A Chain ◽  
The Moment ◽  
And Control

This paper presents the design and analysis of an underactuated, cable driven mechanism for use in a modular robotic snake. The proposed mechanism is composed of a chain of rigid links that rotate on parallel revolute joints and are actuated by antagonistic cable pairs and a multi-radius pulley. This design aims to minimize the cross sectional area of cable actuated robotic snakes and eliminate undesirable nonlinearities in cable displacements. A distinctive feature of this underactuated mechanism is that it allows planar serpentine locomotion to be accomplished with only two modular units, improving the snake’s ability to conform to desired curvature profiles and minimizing the control complexity involved in snake locomotion. First, the detailed mechanism and cable routing scheme are presented, after which the kinematics and dynamics of the system are derived and a comparative analysis of cable routing schemes is performed, to assist with design synthesis and control. The moment of inertia of the mechanism is modeled, for future use in the implementation of three-dimensional modes of snake motion. Finally, a planar locomotion strategy for snake robots is devised, demonstrated in simulation, and compared with previous studies.

scholarly journals Control/Network Codesign Basics for IP-Based Shared Networks

2011 ◽  
Vol 2011 ◽  
pp. 1-23 ◽  
Author(s):  
Miguel Díaz-Cacho Medina ◽  
Emma Delgado Romero ◽  
Antonio Barreiro Blas
Keyword(s):  
Control Systems ◽  
Networked Control Systems ◽  
Transmission Rate ◽  
Design Parameters ◽  
Control Network ◽  
Transport Protocol ◽  
Test Platform ◽  
Shared Networks ◽  
The Stability ◽  
And Control

Network and control relationship is an essential aspect in the design of networked control systems (NCSs). The design parameters are mainly centered in the transmission rate and in the packet structure, and some studies have been made to determine how transmission rate affects the network delay and consequently the stability of the control. In Internet, these analysis are mathematically complex due to the large number of different potential scenarios. Using empirical methods, this work deduces that the transmission scheduling problem of an NCS can be solved by designing an appropriate transport protocol, taken into account high and periodic sampling rates. The transport protocol features are determined by simulation, using a new test platform based on the NS2 network simulation suite, to develop control/network codesign solutions. Conclusions of this paper are that the transport features are packet-loss-based flow control, best effort, and fairness, supplemented by a packet priority scheme.

Thrust Enhancement From Radial Velocity in Squid Inspired Thrusters

2012 ◽  
Author(s):  
Michael Krieg ◽  
Kamran Mohseni
Keyword(s):  
Radial Velocity ◽  
Driving Mechanism ◽  
Low Thrust ◽  
Vortex Ring Formation ◽  
Total Impulse ◽  
Fluid Jets ◽  
Force Range ◽  
And Control ◽  
Thrust Production ◽  
Control Surfaces

Squid and jellyfish generate propulsive forces by successively taking in and expelling high momentum jets of water. This method of propulsion offers several advantages to underwater vehicles/robots. The driving mechanism can be placed internal to the vehicle, reducing the drag associated with an abundance of external thrusters and control surfaces. The thrusters can generate accurate predictable forcing in the low thrust range, while still generating thrust nearly instantaneously over the entire force range. Vortex ring formation dynamics play an important role in creating thrust. It is observed that squid and jellyfish eject fluid jets which are not exactly parallel, and have a contracting velocity in the radial direction. A prototype thruster was developed which generates both parallel and converging propulsive jets. The total impulse of the jet is determined from DPIV techniques to determine the effect a non-zero radial velocity had on thrust production. The radial velocity was observed to increase the total impulse of the jet by 70% for low stroke ratio jets, and 75% for large stroke ratio jets.

scholarly journals A Flywheel Energy Storage and Conversion System for Solar Photovoltaic Applications

1979 ◽  
Author(s):  
A. R. Millner
Keyword(s):  
Energy Storage ◽  
Magnetic Bearing ◽  
Design Parameters ◽  
Energy Storage And Conversion ◽  
Solar Photovoltaic ◽  
Structural Topology ◽  
Flywheel Energy Storage ◽  
Conversion System ◽  
Control Electronics ◽  
And Control

A low-drag, low-power magnetic bearing and a permanent magnet brushless d-c motor-generator have been developed for a satellite flywheel. These will be combined with a terrestrial flywheel and control electronics to make up a flywheel energy storage and conversion system for use in a stand-alone solar photovoltaic residence. Technical and economic performance analyses indicate that, contrary to general thought, a flywheel system will be competitive if not superior to more conventional systems utilizing either present-day or advanced batteries. This derives from the ability of the flywheel to perform the functions of d-c to a-c inversion and optimal impedance matching between the PV arrays and the load in addition to providing energy storage. The motor-generator design will also be discussed. This paper describes the structural topology, performance data, design parameters, and test measurements of the magnetic bearing and motor-generator as well as a description of the flywheel and control electronics to be used. A preliminary discussion of the economic aspects is also included.

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