scholarly journals Design, Optimization, and Experiment on a Bioinspired Jumping Robot with a Six-Bar Leg Mechanism Based on Jumping Stability

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Ziqiang Zhang ◽  
Bin Chang ◽  
Jing Zhao ◽  
Qi Yang ◽  
Xingkun Liu
Keyword(s):  
Dynamic Models ◽  
Rotation Angle ◽  
High Sensitivity ◽  
Optimization Method ◽  
Small Range ◽  
Configuration Optimization ◽  
Inertia Moment ◽  
Object A ◽  
Reduced Mechanism ◽  
Optimization Parameters

A jumping leg with one degree of freedom (DOF) is characterized by high rigidity and simple control. However, robots are prone to motion failure because they might tip over during the jumping process due to reduced mechanism flexibility. Mechanism design, configuration optimization, and experimentation were conducted in this study to achieve jumping stability for a bioinspired robot. With locusts as the imitated object, a one-DOF jumping leg mechanism was designed taking Stephenson-type six-bar mechanism as reference, and kinematic and dynamic models were established. The rotation angle of the trunk and the total inertia moment were used as stability criteria, and the sensitivity of different links to the target was analyzed in detail. With high-sensitivity link lengths as the optimization parameters, a configuration optimization method based on the particle swarm optimization algorithm was proposed in consideration of the different constraint conditions of the jumping leg mechanism. Optimization results show that this method can considerably improve optimization efficiency. A prototype of the robot was developed, and the experiment showed that the optimized trunk rotation angle and total inertia moment were within a small range and can thus meet the requirements of jumping stability. This work provides a reference for the design of jumping and legged robots.

Optimum arrangement of two-stage plug and concentrate recycling RO systems using thermodynamic and exergy analysis

2019 ◽  
Vol 30 (6) ◽  
pp. 3323-3348
Author(s):  
Abbas Naeimi ◽  
Mohammad Hossein Ahmadi ◽  
Milad Sadeghzadeh ◽  
Alibakhsh Kasaeian
Keyword(s):  
Reverse Osmosis ◽  
Water Pressure ◽  
Optimization Method ◽  
Feed Water ◽  
Two Stage ◽  
Content Type ◽  
Optimum Arrangement ◽  
North Of Iran ◽  
Optimization Parameters ◽  
Seawater Reverse Osmosis

Purpose This paper aims to determine the optimum arrangement of a reverse osmosis system in two methods of plug and concentrate recycling. Design/methodology/approach To compare the optimum conditions of these two methods, a seawater reverse osmosis system was considered to produce fresh water at a rate of 4,000 m3/d for Mahyarkala city, located in north of Iran, for a period of 20 years. Using genetic algorithms and two-objective optimization method, the reverse osmosis system was designed. Findings The results showed that exergy efficiency in optimum condition for concentrate recycling and plug methods was 82.6 and 92.4 per cent, respectively. The optimizations results showed that concentrate recycling method, despite a 36 per cent reduction in the initial cost and a 2 per cent increase in maintenance expenses, provides 6 per cent higher recovery and 19.7 per cent less permeate concentration than two-stage plug method. Originality/value Optimization parameters include feed water pressure, the rate of water return from the brine for concentrate recycling system, type of SW membrane, feedwater flow rate and numbers of elements in each pressure vessel (PV). These parameters were also compared to each other in terms of recovery (R) and freshwater unit production cost. In addition, the exergy of all elements was analyzed by selecting the optimal mode of each system.

scholarly journals The Method of MMC Redundancy Optimization Allocation Based on Multi-objective Optimization

2018 ◽  
Vol 173 ◽  
pp. 03075
Author(s):  
Enshu Jin ◽  
Yagu Zhang
Keyword(s):  
Optimization Method ◽  
Normal Operation ◽  
Multi Objective Optimization ◽  
Configuration Optimization ◽  
Multi Objective ◽  
Optimal Value ◽  
Optimization Function ◽  
Multi Level ◽  
Optimization Allocation ◽  
Level Converter

When the modular multi-level converter of the sub-module faults, which will cause the unbalanced system, affect the normal operation of the system, so to the MMC arm configuration redundant sub-module is necessary, if the sub-module faults, redundant sub-modules will replace the fault sub-module maintaining the normal operation of system. In this paper, we propose a reasonable and effective method for the configuration optimization of redundant sub-module based on the three indexes, namely, efficient utilization of redundant sub-module, the number of redundant sub-module and the reliability of the system MMC, considering the three factors, establishing a multi-objective optimization function of redundant configuration, By calculating the optimal value to accurately calculate the number of redundant sub-module of MMC, based on the proposed redundancy configuration optimization method, building a simulation model of MMC 5 level in PSCAD, the results verify the rationality and feasibility of the proposed optimization method.

Optimization of Heating Temperature History for Anisotropic Conductive Film Interconnection

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Yasutada Nakagawa ◽  
Ryohei Yokoyama
Keyword(s):  
Global Optimization ◽  
Heating Temperature ◽  
Optimization Method ◽  
Temperature History ◽  
Optimization Approach ◽  
Anisotropic Conductive Film ◽  
Conductive Film ◽  
Optimization Parameters ◽  
Connection Length ◽  
Conductive Particles

Anisotropic conductive film (ACF) interconnection is used for mounting electronic components, because this method can decrease the mounting area and electric connection length, as well as the thermal stress in the connecting area. An ACF comprises thermosetting resin and conductive particles. The resin is heated and its curing rate and viscosity changes complexly with the heating temperature during the process. There are several requirements for the heating temperature history from the industrial viewpoint such as the reliability of adhesion and energy efficiency. These requirements are related to the curing rate and the viscosity of the resin. A global optimization method proposed for nonlinear programming problems is adopted to optimize the values of the curing reaction parameters and the temperature history. First, the values of parameters in the functions determining the curing rate and viscosity are identified, and the curing rate and viscosity calculated using the values of the parameters agree well with the experimental data. Then, several optimization examples clarify features of the optimum heating temperature history. It is possible to increase the final curing rate to ensure adhesion and to control the viscosity in the bubble-removing process. The period in which bubbles are removed can be changed by the setting of the optimization parameters. It is also possible to minimize the heat input and ensure the required final curing rate. These results clarify that the temperature history for ACF interconnection can be determined accurately by the presented global optimization approach.

A Stochastic Simulation of an HCCI Engine Using an Automatically Reduced Mechanism

2001 ◽  
Author(s):  
Hakan Serhad Soyhan ◽  
Terese Løvås ◽  
Fabian Mauss
Keyword(s):  
Flow Reactor ◽  
Plug Flow ◽  
High Sensitivity ◽  
Ignition Process ◽  
Compression Ignition ◽  
Detailed Chemical Kinetics ◽  
Promising Alternative ◽  
Hcci Engine ◽  
Reduced Mechanism ◽  
Skeletal Mechanism

Abstract Homogeneous Charge Compression Ignition (HCCI) Engines are a promising alternative to the existing Spark Ignition Engines and Compression Ignition Engines. In an HCCI engine, the premixed fuel/air mixture ignites when sufficiently high temperature and pressure is reached. The entire bulk will auto-ignite at almost the same time because the physical conditions are similar throughout the combustion chamber. Therefore it is a justified assumption to consider the chemical reactions to be the rate-determining step for the ignition process. This gives us the opportunity to formulate a simple zero-dimensional model with detailed chemical kinetics for the calculations of the ignition process. Ignition calculations using this model have predicted a high sensitivity to fluctuations in temperature and fuel compositions. These predictions have later been confirmed by experiments. Partially stirred plug flow reactor (PaSPFR) can be used to conquer the assumption of homogeneity. The assumption is replaced by that of statistical homogeneity and thus statistical fluctuations caused by inhomogeneities can be studied. However, the CPU-time needed for this approach is increased considerably and the usage of mechanism reduction becomes evident. In this paper, we demonstrate how a reduced mechanism for natural gas as fuel is derived automatically. The original mechanism by Warnatz (589 reactions, 53 species) is first reduced to a skeletal mechanism (481 reactions, 43 species). By introduction of the quasi steady state assumption, the skeletal mechanism is reduced further to 23 species and 20 global reactions. The accuracy of the final mechanism is demonstrated using the stochastic reactor tool for an HCCI engine.

scholarly journals Modeling of Top Scroll Profile Using Equidistant-Curve Approach for a Scroll Compressor

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Tao Liu ◽  
Zaixin Wu
Keyword(s):  
Dynamic Models ◽  
Rotation Angle ◽  
Volume Ratio ◽  
Geometric Continuity ◽  
Leakage Loss ◽  
Scroll Compressor ◽  
Order Continuity ◽  
Circular Arc ◽  
First Order ◽  
Generation Line

Scroll profile plays a key role in determining the performance of a scroll compressor. In this study geometric and dynamic characteristics of the scroll profile are analyzed to investigate the influence of its geometric continuity on property of a scroll compressor. Firstly, scroll profiles are created to redesign the geometry of scroll wrap by using the equidistant-curve approach on the basis of a generation line consisting of involute of circle and circular arc. Subsequently, the geometric and dynamic models of the scroll compressor are established. These models are related to parameters of the generation line of scroll profile and rotation angle of a moving scroll. Lastly, some simulation examples of second-order continuity (SOC) scroll profile are compared with first-order continuity (FOC) scroll profiles and some important conclusions are obtained. Results show that SOC scroll profile is superior to FOC profile in terms of volume ratio, stability of gas force, and possible leakage loss in a scroll compressor.

Study on Precision Machining Titanium Alloy Thin-Walled Parts

2011 ◽  
Vol 314-316 ◽  
pp. 1778-1782
Author(s):  
Ming Hai Wang ◽  
Zhong Hai Liu ◽  
Wei Wang
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Aircraft Engine ◽  
Optimization Method ◽  
Precision Machining ◽  
Machining Parameters ◽  
Reduction Efficiency ◽  
Efficiency Increase ◽  
Optimization Parameters ◽  
Thin Walled

In order to obtain the aims of weight reduction, efficiency increase and quality assurance of thin-walled parts of aircraft engine, the titanium alloy thin-walled parts are machined by precision machining method in the experiment. In this paper the precision machining method is used to cut titanium alloy thin-walled parts. The data of surface roughness is chosen as constraint conditions, and machining parameters will be optimized. The optimization parameters is feasible in this experiment, the optimization method is helpful to improve machining parameters and machining technology of titanium alloy thin-walled.

scholarly journals Neural and behavioural responses of the pollen-specialist bee Andrena vaga to Salix odours

2021 ◽  
Author(s):  
Hannah Burger ◽  
Melanie Marquardt ◽  
Katharina Babucke ◽  
Kim C. Heuel ◽  
Manfred Ayasse ◽  
...  
Keyword(s):  
Visual Cues ◽  
Floral Scent ◽  
Effective Means ◽  
High Sensitivity ◽  
Host Finding ◽  
Food Sources ◽  
Small Range ◽  
Behavioural Activity ◽  
Electroantennographic Detection ◽  
Behavioural Experiments

An effective means of finding food is crucial for organisms. Whereas specialized animals select a small number of potentially available food sources, generalists use a broader range. Specialist (oligolectic) bees forage on a small range of flowering plants for pollen and use primarily olfactory and visual cues to locate their host flowers. So far, however, little is known about the specific cues oligoleges use to discriminate between hosts and non-hosts and how floral scent compounds of hosts and non-hosts are processed in the bees’ olfactory system. In this study, we recorded physiological responses of the antennae (electroantennographic detection coupled to gas chromatography GC-EAD) and in the brain (optical imaging, GC-imaging), and studied host-finding behaviour of oligolectic Andrena vaga bees, a specialist on Salix plants. In total, we detected 37 physiologically active compounds in host and non-host scents. 4-Oxoisophorone, a common constituent in the scent of many Salix species, evoked strong responses in the antennal lobe glomeruli of A. vaga, but not the generalist honeybee Apis mellifera. The specific glomerular responses to 4-oxoisophorone in natural Salix scents reveals a high degree of specialization in A. vaga for this typical Salix odorant component. In behavioural experiments, we found olfactory cues to be the key attractants for A. vaga to Salix hosts, which are also used to discriminate between hosts and non-hosts, and demonstrated a behavioural activity for 4-oxoisophorone. A high sensitivity to floral scents enables the specialized bees to effectively find flowers and it appears that A. vaga bees are highly tuned to 4-oxoisophorone at a very low concentration.

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