Straight-Line Mechanisms as One Building Element of Small Precise Robotic Devices

2014 ◽  
Vol 613 ◽  
pp. 96-101 ◽  
Author(s):  
Jaroslav Hricko
Keyword(s):  
Compliant Mechanisms ◽  
Building Blocks ◽  
Linear Motion ◽  
Kinematics Analysis ◽  
Positioning Accuracy ◽  
Building Element ◽  
Revolute Joints ◽  
Straight Line ◽  
Robotic Devices ◽  
Straight Line Mechanism

Small precise robotic devices, working on principle of compact compliant mechanisms, must meet the conditions to high positioning accuracy what mean moving in straight-line too. But, compliant mechanisms are usually produced by equivalent of revolute joints, therefore in design of small robotic devices is necessary apply knowledge from design of one type of specialized mechanisms – straight-line mechanisms. This paper presents some straight-line mechanism and its applications to design of some small precise robotic devices. According to kinematics analysis most known straight-line mechanisms are evaluated for their application in compliant mechanisms. Such devices are transformed to flexure structures. Consequently, these devices are important building blocks to design some linear-motion stages and/or micro-grippers.

An Examination of Trispiral Hinges Suitable for Use in ABS-Based Rapid Prototyping of Compliant Mechanisms

2014 ◽  
Author(s):  
John A. Mirth
Keyword(s):  
Rapid Prototyping ◽  
Fused Deposition Modeling ◽  
Compliant Mechanisms ◽  
Low Cost ◽  
Neutral Position ◽  
Joint Rotation ◽  
Parasitic Motion ◽  
Fused Deposition ◽  
Straight Line ◽  
Straight Line Mechanism

This paper examines the use of a trispiral hinge in compliant mechanisms generated by low cost, ABS-based, rapid prototyping machines. Hinges are examined to establish relationships between hinge geometry parameters (core radius, spiral angle, spiral pitch, and spiral thickness) and hinge performance (in-plane rotation, off-axis stability). A number of joint parameter combinations are found that provide good joint rotation characteristics with minimal off-axis instability. These joints allow for joint rotations up to ±90 degrees from a neutral position with little parasitic motion during the rotation. The implementation of these joints is further examined through the building and testing of fully compliant mechanisms based on the Roberts and Hoeken approximate straight-line mechanism geometries. The fully compliant mechanisms are shown to have the ability to closely recreate the approximate straight-line motion of the equivalent 4-bar chains. As such, the trispiral joint provides promise as a joint type that can be used effectively in conjunction with fused deposition modeling (FDM) machines that use ABS as the build material.

A planar reconfigurable linear rigid-body motion linkage with two operation modes

2014 ◽  
Vol 228 (16) ◽  
pp. 2985-2991 ◽  
Author(s):  
Guangbo Hao ◽  
Xianwen Kong ◽  
Xiuyun He
Keyword(s):  
Rigid Body ◽  
Single Mode ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Reference Guide ◽  
Revolute Joints ◽  
Operation Modes ◽  
Straight Line ◽  
Motion Stage ◽  
Motion Mode

A planar reconfigurable linear (also rectilinear) rigid-body motion linkage (RLRBML) with two operation modes, that is, linear rigid-body motion mode and lockup mode, is presented using only R (revolute) joints. The RLRBML does not require disassembly and external intervention to implement multi-task requirements. It is created via combining a Robert’s linkage and a double parallelogram linkage (with equal lengths of rocker links) arranged in parallel, which can convert a limited circular motion to a linear rigid-body motion without any reference guide way. This linear rigid-body motion is achieved since the double parallelogram linkage can guarantee the translation of the motion stage, and Robert’s linkage ensures the approximate straight line motion of its pivot joint connecting to the double parallelogram linkage. This novel RLRBML is under the linear rigid-body motion mode if the four rocker links in the double parallelogram linkage are not parallel. The motion stage is in the lockup mode if all of the four rocker links in the double parallelogram linkage are kept parallel in a tilted position (but the inner/outer two rocker links are still parallel). In the lockup mode, the motion stage of the RLRBML is prohibited from moving even under power off, but the double parallelogram linkage is still moveable for its own rotation application. It is noted that further RLRBMLs can be obtained from the above RLRBML by replacing Robert’s linkage with any other straight line motion linkage (such as Watt’s linkage). Additionally, a compact RLRBML and two single-mode linear rigid-body motion linkages are presented.

Design and Development of a Novel Infant Surgical Table for 4-DOF Patient Manipulation

2007 ◽  
Author(s):  
Kimberly Ryland ◽  
Carl A. Nelson ◽  
Thomas Hejkal
Keyword(s):  
Premature Infants ◽  
Laser Photocoagulation ◽  
Occupational Injury ◽  
Quality Care ◽  
Blood Vessel Development ◽  
Locking Mechanism ◽  
Straight Line ◽  
Vessel Development ◽  
Straight Line Mechanism ◽  
Standard Table

Retinopathy of Prematurity, caused by abnormal blood vessel development in the retina of premature infants, is a leading cause of childhood blindness. It is treated using laser photocoagulation. Current methods require the surgeon to assume awkward standing positions, which can result in injury to the surgeon if repeated often. To assist surgeons in providing quality care and prevent occupational injury, a new infant surgical table was designed. The engineered solution is an attachment to a standard surgical table, saving cost and space. This takes advantage of the adjustable height and tilt provided by the standard table, while 360° rotation designed into the attachment allows the surgeon to sit during surgery. The critical cords and tubes are routed through the attachment to avoid pulling and kinking. A four-bar locking mechanism allows easy attachment to standard medical railing. Finally, a straight line mechanism provides positive locking of the rotation, allowing precise positioning of the infant.

Biomimetic Compliant System for Smart Actuator-Driven Aquatic Propulsion: Preliminary Results

Aerospace ◽  
2003 ◽  
Author(s):  
Brian P. Trease ◽  
Kerr-Jia Lu ◽  
Sridhar Kota
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Building Blocks ◽  
Biologically Inspired ◽  
Preliminary Results ◽  
Rib Structure ◽  
Actuator System ◽  
Smart Actuator ◽  
New Applications ◽  
Estimate System

Biomimetic design takes principles from nature to employ in engineering problems. Such designs are hoped to be quiet, efficient, robust, and versatile, having taken advantage of optimization via natural selection. However, the emulation of specific biological devices poses a great challenge because of complicated, arbitrary, and over-redundant designs. Compliant mechanisms are of immediate appeal in addressing the problem of complex, biomimetic deformation because of their inherent flexibility and distributed compliance. The goal of this research is to develop a biologically-inspired hydrofoil for aquatic propulsion, by assembling planar compliant mechanism building blocks to generate complex 3-D deformations. The building block is a rib structure generated from topology optimization. An ADAMS model is then created to quickly visualize motion and estimate system characteristics. System refinement is achieved through further size and shape optimization of individual ribs. Testing of a single-rib and dual-actuator system is currently in progress. The preliminary results have demonstrated the potential of this combined approach to quickly identify and evaluate new applications that may result from building blocks.

Mathematical Model for Face-Hobbed Straight Bevel Gears

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Yi-Pei Shih
Keyword(s):  
Mathematical Model ◽  
Bevel Gear ◽  
Tooth Contact Analysis ◽  
Rolling Circle ◽  
High Productivity ◽  
Bevel Gears ◽  
Straight Line ◽  
Base Circle ◽  
Straight Line Mechanism ◽  
Straight Lines

Face hobbing, a continuous indexing and double-flank cutting process, has become the leading method for manufacturing spiral bevel gears and hypoid gears because of its ability to support high productivity and precision. The method is unsuitable for cutting straight bevel gears, however, because it generates extended epicycloidal flanks. Instead, this paper proposes a method for fabricating straight bevel gears using a virtual hypocycloidal straight-line mechanism in which setting the radius of the rolling circle to equal half the radius of the base circle yields straight lines. This property can then be exploited to cut straight flanks on bevel gears. The mathematical model of a straight bevel gear is developed based on a universal face-hobbing bevel gear generator comprising three parts: a cutter head, an imaginary generating gear, and the motion of the imaginary generating gear relative to the work gear. The proposed model is validated numerically using the generation of face-hobbed straight bevel gears without cutter tilt. The contact conditions of the designed gear pairs are confirmed using the ease-off topographic method and tooth contact analysis (TCA), whose results can then be used as a foundation for further flank modification.

Kinematics Analysis of a New 3-DOF Rotational Parallel Mechanism

2012 ◽  
Author(s):  
Ziming Chen ◽  
Wen-ao Cao ◽  
Zhen Huang
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Kinematics Analysis ◽  
Revolute Joints ◽  
The Relationship ◽  
Orientation Workspace

In this paper a new rotational parallel mechanism which has three rotational freedoms is studied. This mechanism consists of only revolute joints. In this mechanism, no joints intersect with each other. The constraint and motion properties are analyzed. The inverse kinematics is solved and the orientation workspace is studied. In the end, the relationship between the orientation workspace and the link lengths is shown.

Components for the Design of Lamina Emergent Mechanisms

2007 ◽  
Author(s):  
Joseph O. Jacobsen ◽  
Larry L. Howell ◽  
Spencer P. Magleby
Keyword(s):  
Change Point ◽  
Compliant Mechanisms ◽  
Building Blocks ◽  
Complex Motion ◽  
Initial State ◽  
Manufacturing Costs ◽  
Minimal Volume ◽  
Resulting Effect ◽  
Potential Benefits ◽  
Planar Materials

This paper presents components for lamina emergent mechanism (LEM) that can be used as building blocks to create mechanisms capable of more complex motion. As the name suggests, lamina emergent mechanisms are fabricated out of planar materials (the lamina) but their motion is out of that plane (emergent). Lamina emergent mechanisms can provide benefits that include reduced manufacturing costs and minimal volume when in the planar state. The compact initial state of LEMs is beneficial in reducing shipping costs, especially in volume critical applications. LEMs also exhibit the potential benefits of compliant mechanisms, namely increased precision, reduced weight, reduced wear, and part count reduction. Due to the deflection of their members, compliant mechanisms have the ability to store energy, and the resulting effect can be used to perform the function of springs. The LEM components presented in this paper include flexible segments, and mechanisms with behaviors similar to planar change-point four-bar and six-bar mechanisms, and spherical change-point mechanisms.

Sign in / Sign up

Export Citation Format

Share Document