Mechanical Design

2021 ◽  
pp. 329-342
Author(s):  
C. Julian Chen
Keyword(s):  
Temperature Variation ◽  
Mechanical Design ◽  
Single Tube ◽  
Mechanical Structure ◽  
Central Piece ◽  
Historical Importance

This chapter discusses various mechanical designs for STM and AFM. The central piece of the mechanical design of STM and AFM is the course positioner. Therefore, various types of course positioners are also discussed. The louse and the pocket-size STM are discussed first. It is of significant historical importance but no longer popular today. The single-tube STM has a very simple mechanical structure, and still the basis of the most popular commercial STM and AFM. The Besocke-type or the beetles is very popular among builders of special-purpose STM due its immunity to temperature variation and vibration. For STM requiring superb stability, the walker and the kangaroo are the preferred design. The commercial nanostepper, the Inchworm, is described. It has been successfully used by many designers of special-purpose STM.

scholarly journals Mechanical Design and Gait Optimization of Hydraulic Hexapod Robot Based on Energy Conservation

2020 ◽  
Vol 10 (11) ◽  
pp. 3884
Author(s):  
Shou Zhai ◽  
Bo Jin ◽  
Yilu Cheng
Keyword(s):  
Energy Consumption ◽  
Mechanical Design ◽  
Optimal Solution ◽  
Design Sensitivity ◽  
Unit Weight ◽  
Total Power ◽  
Hexapod Robot ◽  
Walking Robot ◽  
Mechanical Structure ◽  
Highly Nonlinear

Minimizing energy consumption is significant for the hydraulic walking robot to reduce its power unit weight and increase working hours. However, most robot leg designs are inefficient due to their bio-mimetic or mission-specific mechanical structure. This paper presents a structural optimization method of the hydraulic walking robot by optimizing its mechanical structure and gait parameters simultaneously. The mathematical model of the total power of the hydraulic hexapod robot (HHR) is established, which is derived based on a general template for designing the hydraulic walking robot. The archive-based micro genetic algorithm (AMGA) is used to optimize the highly nonlinear multi-constraint multi-objective optimizations. In the optimal solution, the energy consumption of the HHR has reduced more than 40% by comparison with the original mechanical structure and gait parameter. Design sensitivity analysis is carried out to determine the regulation of mechanical structure, and a virtual prototype is used to verify the effectiveness of the proposed methods.

Thermo-Elastic Design of Flexure for Spaceborn Opto-Mechanical Payloads

2011 ◽  
Vol 110-116 ◽  
pp. 5292-5300
Author(s):  
Naimesh Patel ◽  
J.B. Rami ◽  
A.P. Vora ◽  
C.P. Dewan ◽  
D. Subrahmanyam
Keyword(s):  
Temperature Variation ◽  
Dissimilar Materials ◽  
Optical Element ◽  
Elastic Behavior ◽  
Response Analysis ◽  
Optical Parameters ◽  
Mechanical Assembly ◽  
Optical Elements ◽  
Vibration Load ◽  
Mechanical Structure

Spaceborn optical payload consists of optical elements supported by mechanical structure in desired orientation. Mechanical structure made up of various dissimilar materials like aluminum & invar possess dissimilar thermo-elastic behavior. Opto-mechanical assembly subjected to temperature change will results to change in optical element orientation which ultimately leads to change in optical parameters like registration. This is mainly due to dissimilar materials subjected to temperature variation will result to structural distortion. Use of dissimilar materials in an Opto- mechanical payload affects the angular stability of optical element due to temperature variation and results to change in optical element orientation. Flexure is required to be introduced within the opto-mechanical system having dissimilar materials to accommodate differential thermal expansion due to temperature variation and to maintain the registration. This paper explains, stability in dichroic element orientation of an opto-mechanical payload having dissimilar material & flexure design to maintain the orientation in opto-mechanical payload subjected to temperature variation without deterioration of fundamental frequency. It also explains theoretical thermo-elastic analysis and experimental test for validation of design, static and dynamic structural analysis like frequency response analysis to check the flexure survivability for vibration load.

MECHANICAL STRUCTURE IMPROVEMENT OF AN UPPER LIMB REHABILITATION ROBOT: BASED ON AN EQUIVALENT KINEMATIC MODEL

2013 ◽  
Vol 13 (06) ◽  
pp. 1340021
Author(s):  
CHONG LI ◽  
ENCHEN LIU ◽  
LINHONG JI
Keyword(s):  
Upper Limb ◽  
Degrees Of Freedom ◽  
Mechanical Design ◽  
Kinematic Model ◽  
Clinical Effectiveness ◽  
Motor Deficits ◽  
Upper Limb Rehabilitation ◽  
Robotic Arms ◽  
Mechanical Structure ◽  
Aged People

Several rehabilitation robots for upper limbs have been introduced so far, and clinical effectiveness was reported in several studies for the aged people or patients with stroke. Upper limb motor deficits of the patients have to be identified during the motor training, which requires the flexibility of mechanical structure. However, the users have difficulties in driving the previous robotic arms precisely because of the previous mechanical structure, especially when they are required to track a circle. This article gives a kinematic analysis on the previous mechanical structure of the previous robot, which is a two bar-linkage, two degrees of freedom mechanism, then solves the force on the handle grip during user's operation based on an equivalent kinematic model. The key of the problem is that force directions exerted by the user are not in the correct directions to drive the robot. Therefore, a new mechanical design using parallel robotic arms is suggested. The improvement is justified by comparing results from tracking circles using different robots.

scholarly journals Instability and Drift Phenomena in Switching RF-MEMS Microsystems

Actuators ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 15
Author(s):  
Viviana Mulloni
Keyword(s):  
Temperature Variation ◽  
Rf Mems ◽  
Charge Trapping ◽  
Mechanical Deformation ◽  
Mems Switches ◽  
Mechanical Structure ◽  
Comprehensive View ◽  
Contact Wear ◽  
Fabrication Tolerances ◽  
Dielectric Charge

MEMS switches include mobile beams in their mechanical structure and these suspended parts are essential for the device functioning. This paper illustrates the most important instability phenomena related to MEMS switches. Starting from the most important instability exploited in these devices—the electrical actuation—the paper also analyzes other important effects related to instability phenomena, which are very common in this type of technology. Instabilities due to dielectric charge trapping, fabrication tolerances, mechanical deformation, contact wear, and temperature variation are duly analyzed, giving a comprehensive view of the complexity encountered in the reliable functioning of these apparently simple devices.

scholarly journals A Hyper-redundant Elephant’s Trunk Robot with an Open Structure: Design, Kinematics, Control and Prototype

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Yongjie Zhao ◽  
Xiaogang Song ◽  
Xingwei Zhang ◽  
Xinjian Lu
Keyword(s):  
Control System ◽  
Mechanical Design ◽  
Kinematic Model ◽  
Structure Design ◽  
Simulation Software ◽  
Open Structure ◽  
Complex Tasks ◽  
Mechanical Structure ◽  
In Series ◽  
Motion Characteristics

AbstractAs for the complex operational tasks in the unstructured environment with narrow workspace and numerous obstacles, the traditional robots cannot accomplish these mentioned complex operational tasks and meet the dexterity demands. The hyper-redundant bionic robots can complete complex tasks in the unstructured environments by simulating the motion characteristics of the elephant’s trunk and octopus tentacles. Compared with traditional robots, the hyper-redundant bionic robots can accomplish complex tasks because of their flexible structure. A hyper-redundant elephant’s trunk robot (HRETR) with an open structure is developed in this paper. The content includes mechanical structure design, kinematic analysis, virtual prototype simulation, control system design, and prototype building. This design is inspired by the flexible motion of an elephant’s trunk, which is expansible and is composed of six unit modules, namely, 3UPS-PS parallel in series. First, the mechanical design of the HRETR is completed according to the motion characteristics of an elephant’s trunk and based on the principle of mechanical bionic design. After that, the backbone mode method is used to establish the kinematic model of the robot. The simulation software SolidWorks and ADAMS are combined to analyze the kinematic characteristics when the trajectory of the end moving platform of the robot is assigned. With the help of ANSYS, the static stiffness of each component and the whole robot is analyzed. On this basis, the materials of the weak parts of the mechanical structure and the hardware are selected reasonably. Next, the extensible structures of software and hardware control system are constructed according to the modular and hierarchical design criteria. Finally, the prototype is built and its performance is tested. The proposed research provides a method for the design and development for the hyper-redundant bionic robot.

The new CM-Series TEMs: integration of a five-axis motorized, fully computer-controlled goniometer

1993 ◽  
Vol 51 ◽  
pp. 258-259
Author(s):  
Marc J.C. de Jong ◽  
P. Emile S.J. Asselbergs ◽  
Max T. Otten
Keyword(s):  
Mechanical Design ◽  
Computer Control ◽  
Objective Lens ◽  
Access Port ◽  
Vibration Stability ◽  
Transmission Electron ◽  
Computer Controlled ◽  
High Degree ◽  
Five Axis ◽  
Five Axes

A new step forward in Transmission Electron Microscopy has been made with the introduction of the CompuStage on the CM-series TEMs: CM120, CM200, CM200 FEG and CM300. This new goniometer has motorization on five axes (X, Y, Z, α, β), all under full computer control by a dedicated microprocessor that is in communication with the main CM processor. Positions on all five axes are read out directly - not via a system counting motor revolutions - thereby providing a high degree of accuracy. The CompuStage enters the octagonal block around the specimen through a single port, allowing the specimen stage to float freely in the vacuum between the objective-lens pole pieces, thereby improving vibration stability and freeing up one access port. Improvements in the mechanical design ensure higher stability with regard to vibration and drift. During stage movement the holder O-ring no longer slides, providing higher drift stability and positioning accuracy as well as better vacuum.

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