Mechanical Design and Dynamics Simulation of Locust-Inspired Straight Line Four-Bar Jumping Mechanism

2016 ◽  
pp. 429-442 ◽  
Author(s):  
Xiaojuan Mo ◽  
Wenjie Ge ◽  
Shaocong Wang ◽  
Donglai Zhao
Keyword(s):  
Mechanical Design ◽  
Dynamics Simulation ◽  
Straight Line

Design and operation of a tripod walking robot via dynamics simulation

Robotica ◽  
2010 ◽  
Vol 29 (5) ◽  
pp. 733-743 ◽  
Author(s):  
Conghui Liang ◽  
Hao Gu ◽  
Marco Ceccarelli ◽  
Giuseppe Carbone
Keyword(s):  
Mechanical Design ◽  
Low Cost ◽  
Three Dimensional ◽  
The Body ◽  
Dynamics Simulation ◽  
Walking Ability ◽  
Walking Robot ◽  
Three Dimensional Model ◽  
Software Environment ◽  
Leg Mechanisms

SUMMARYA mechanical design and dynamics walking simulation of a novel tripod walking robot are presented in this paper. The tripod walking robot consists of three 1-degree-of-freedom (DOF) Chebyshev–Pantograph leg mechanisms with linkage architecture. A balancing mechanism is mounted on the body of the tripod walking robot to adjust its center of gravity (COG) during walking for balancing purpose. A statically stable tripod walking gait is performed by synchronizing the motions of the three leg mechanisms and the balancing mechanism. A three-dimensional model has been elaborated in SolidWorks® engineering software environment for a characterization of a feasible mechanical design. Dynamics simulation has been carried out in the MSC.ADAMS® environment with the aim to characterize and to evaluate the dynamic walking performances of the proposed design with low-cost easy-operation features. Simulation results show that the proposed tripod walking robot with proper input torques, gives limited reaction forces at the linkage joints, and a practical feasible walking ability on a flatten ground.

SHAFT LOADS ON AZIMUTH PROPULSORS IN OBLIQUE FLOW AND WAVES

2021 ◽  
Vol 153 (A1) ◽  
Author(s):  
H Amini ◽  
S Steen
Keyword(s):  
Mechanical Design ◽  
Bending Moment ◽  
Ship Hull ◽  
Propeller Shaft ◽  
Towing Tank ◽  
Oblique Flow ◽  
Straight Line ◽  
Calm Water ◽  
Bending Loads ◽  
Marine Technology

A range of model experiments have been carried out in calm water and waves for an oil spill vessel model with twin tractor azimuth thrusters at different heading angles and advance coefficients in the large towing tank at the Marine Technology Centre in Trondheim, Norway. Propeller shaft bending loads have been measured using a shaft dynamometer capable of measuring all shaft side force and bending moment components as well as propeller torque and thrust. The results include the loads on the propeller shaft with and without the presence of a ship hull model at the same heading angles and advance velocities in order to study the wake influence from the ship hull on the hydrodynamic loads. Results show that the ship hull wake has a much stronger effect on the propeller loads when the propeller is azimuthed outward from the ship hull centreline than inward. Measurements from the experiments in waves are also presented for the same thruster model in a straight-line course for both the head and following sea states under different wave conditions. Larger bending loads are found in head sea conditions compared with the following sea conditions. Generally it is found that the shaft bending loads and lateral forces are quite large, which is important to consider in the mechanical design layout and for dimensioning of components.

Paper 12: A Long Distance Laser Alignment System

1968 ◽  
Vol 183 (4) ◽  
pp. 65-66
Author(s):  
G. J. Reicher ◽  
K. D. Harris
Keyword(s):  
Mechanical Design ◽  
Road Construction ◽  
Practical Experience ◽  
Long Distance ◽  
Tunnel Boring ◽  
Laser Alignment ◽  
Straight Line ◽  
Alignment System ◽  
Improved Stability ◽  
True Position

An improved laser alignment aid has been designed and built for use in engineering operations such as tunnel boring, pipe laying, or road construction to provide a permanent straight line which maintains its true position between periodic checks by a surveyor, thus avoiding expensive errors. A laser tube has been used which has sealed mirror construction, and the mechanical design is such as to give improved stability in the field. This makes for a second generation instrument which should allow more widespread practical experience of lasers to be obtained in the open.

Design of Bio-Inspired Mobile Robot Using Piezoelectric Transducers As Drives

2017 ◽  
Author(s):  
Jovana Jovanova ◽  
Filip Dobrivojevski ◽  
Martina Dimoska
Keyword(s):  
Mobile Robot ◽  
Piezoelectric Transducer ◽  
Conceptual Development ◽  
Mechanical Design ◽  
Piezoelectric Transducers ◽  
Structural Components ◽  
Design Constraints ◽  
Straight Line ◽  
And Control ◽  
Complex Trajectories

This paper focuses on the design and development of a bio-inspired mobile robot using piezoelectric transducers as drives. The design of the device aimed to imitate the trajectory movement of a crawl-like animal. Design constraints as producing controlled movement with piezoelectric transducer, as well as the combination of multiple piezoelectric patches into one mobile robot are presented in their practical aspects. The robot uses 2 piezoelectric transducers as main drives, but also as main structural components of the device. The patches are connected with a thin light rod, and the kinematic of movement is achieved with 4 tiny wooden legs connected on each of the patches. The project investigates the possibility and effectiveness of the piezoelectric transducers for movement of the bio-inspired mobile robot. From conceptual development, to the mechanical design and control, the mobile robot is used to test different trajectories of movement. Ni RIO Evaluation kit has been incorporated as a real-time and FPGA control platform for the mobile robot while using Labview programing environment. To accomplish complex trajectories of movement the velocity of the robot was measured for straight line and rotation of the robot.

scholarly journals Fundamental Studies of Rapidly Fabricated On-Chip Passive Micromixer for Modular Microfluidics

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 153
Author(s):  
Wenpeng Guo ◽  
Li Tang ◽  
Biqiang Zhou ◽  
Yingsing Fung
Keyword(s):  
Microfluidic Chip ◽  
Dynamics Simulation ◽  
Experimental Result ◽  
Continuous Mixing ◽  
Straight Line ◽  
Smooth Channel ◽  
Computational Flow Dynamics ◽  
Passive Micromixer ◽  
On Chip ◽  
Optimized Conditions

Micromixers play an important role in many modular microfluidics. Complex on-chip mixing units and smooth channel surfaces ablated by lasers on polymers are well-known problems for microfluidic chip fabricating techniques. However, little is known about the ablation of rugged surfaces on polymer chips for mixing uses. This paper provides the first report of an on-chip compact micromixer simply, easily and quickly fabricated using laser-ablated irregular microspheric surfaces on a polymethyl methacrylate (PMMA) microfluidic chip for continuous mixing uses in modular microfluidics. The straight line channel geometry is designed for sequential mixing of nanoliter fluids in about 1 s. The results verify that up to about 90% of fluids can be mixed in a channel only 500 µm long, 200 µm wide and 150 µm deep using the developed micromixer fabricating method under optimized conditions. The computational flow dynamics simulation and experimental result agree well with each other.

Wingbeat Generation for a 15 DOF Flexible-Wing Aerial Vehicle Using Cosine Wave Functions

2017 ◽  
Vol 05 (02) ◽  
pp. 115-127
Author(s):  
Willson Amalraj Arokiasami ◽  
Prahlad Vadakkepat ◽  
Abdullah Al Mamun
Keyword(s):  
Mechanical Design ◽  
Cost Effective ◽  
Wave Functions ◽  
Dynamics Simulation ◽  
Forward Dynamics ◽  
Aerodynamic Forces ◽  
Joint Torques ◽  
Flexible Wing ◽  
Wind Gusts ◽  
Aerial Vehicle

Birds and conventional airplanes control their flight in a different manner. Conventional airplanes maneuver themselves by means of moving surfaces, while birds can bend, twist and deform their wings and adapt to unforeseen conditions such as wind gusts. However, if planes can do exactly as the birds do they can gain agility, more lift, less drag while consuming less fuel. This work aims to address this issue. Therefore, approaches of wingbeat generation for a 15 DOF flexible-wing aerial vehicle are developed in this paper. A computationally cost-effective cosine wave function-based algorithm that computes a set of wingbeats enabling the aerial vehicle to follow a desired trajectory in a realistic manner is discussed. The flexible-wing aerial vehicle is modeled similar to a seagull with an articulated skeleton. Motion of the aerial vehicle is simulated by applying joint torques and aerodynamic forces over a period of time in forward dynamics simulation. Wing and tail feather motions generate lift in the aerial vehicle, which makes it possible for the aerial vehicle to trace predefined paths. The solidworks mechanical design is used as input into Matlab SimMechanics for visualization. The results are promising for the construction of bird-like aerial vehicles.

Dynamics Simulation Research of Planar Four-Bar Mechanism with Multi-Joint Clearance

2013 ◽  
Vol 860-863 ◽  
pp. 2650-2653 ◽  
Author(s):  
Shao Jun Bo ◽  
Xiao Wang
Keyword(s):  
Mechanical System ◽  
Mechanical Design ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Joint Clearance ◽  
Kinematic Pair ◽  
Simulation Research ◽  
Preliminary Study ◽  
Simulation Results ◽  
Dynamics Models

On the basis of dynamics simulation software ADAMS, we built dynamics models of planar four-bar mechanism, it built the model of contact force and friction to analysis the dynamics simulation of mechanism. we made a preliminary study on the effect on the flexible components and the backlash of the kinematic pair on mechanical system dynamics characteristics. The result showed that mechanism with single joint clearance had little influence on the mechanism speed and had some impact on mechanism acceleration. Mechanism with multi-joint clearance had bigger effect on the mechanism and acceleration appeared noticeable fluctuation, this model was closer to the phenomenon of objects movements in reality. The simulation results provided reliable reference of mechanical design.

Microdensitometer—computer correlation analysis of ultrastructural periodicity

1978 ◽  
Vol 36 (2) ◽  
pp. 32-33
Author(s):  
D.R. Ensor ◽  
C.G. Jensen ◽  
J.A. Fillery ◽  
R.J.K. Baker
Keyword(s):  
Correlation Analysis ◽  
Background Noise ◽  
Computer Control ◽  
Optical Diffraction ◽  
Screw Thread ◽  
Straight Line ◽  
Computer Storage ◽  
Correlation Process ◽  
Electron Microscope Image ◽  
Fixed Beam

Because periodicity is a major indicator of structural organisation numerous methods have been devised to demonstrate periodicity masked by background “noise” in the electron microscope image (e.g. photographic image reinforcement, Markham et al, 1964; optical diffraction techniques, Horne, 1977; McIntosh,1974). Computer correlation analysis of a densitometer tracing provides another means of minimising "noise". The correlation process uncovers periodic information by cancelling random elements. The technique is easily executed, the results are readily interpreted and the computer removes tedium, lends accuracy and assists in impartiality.A scanning densitometer was adapted to allow computer control of the scan and to give direct computer storage of the data. A photographic transparency of the image to be scanned is mounted on a stage coupled directly to an accurate screw thread driven by a stepping motor. The stage is moved so that the fixed beam of the densitometer (which is directed normal to the transparency) traces a straight line along the structure of interest in the image.

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

Human Enamel Replication

1976 ◽  
Vol 34 ◽  
pp. 180-181
Author(s):  
Norman L. Dockum ◽  
John G. Dockum
Keyword(s):  
Organic Matrix ◽  
Human Teeth ◽  
Human Enamel ◽  
Straight Line ◽  
Ultrastructural Characteristics

Ultrastructural characteristics of fractured human enamel and acid-etched enamel were compared using acetate replicas shadowed with platinum and palladium. Shadowed replications of acid-etched surfaces were also obtained by the same method.Enamel from human teeth has a rod structure within which there are crystals of hydroxyapatite contained within a structureless organic matrix composed of keratin. The rods which run at right angles from the dentino-enamel junction are considered to run in a straight line perpendicular to the perimeter of the enamel, however, in many areas these enamel rods overlap, interlacing and intertwining with one another.

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