An Offset Panel Technique for Thick Rigidily Foldable Origami

2014 ◽  
Author(s):  
Bryce J. Edmondson ◽  
Robert J. Lang ◽  
Spencer P. Magleby ◽  
Larry L. Howell
Keyword(s):  
Mechanism Design ◽  
Source Model ◽  
Revolute Joint ◽  
Revolute Joints ◽  
Joint Plane ◽  
Kinematic Mechanisms ◽  
Panel Thickness ◽  
Kinematic Motion ◽  
Panel Design

A technique for thickness accommodation in origami-inspired mechanism design is introduced. Mathematically, origami panels are generally assumed to be planar with zero thickness. Origami models can be viewed as kinematic mechanisms where folds are revolute joints and panels are links. An origami-inspired mechanism can achieve the same kinematic motion as the paper origami source model if all joints lie along the folds in the zero-thickness plane. The panels are stacked in sequence in the closed (stowed) position. A joint plane is chosen and each panel is given extensions connecting each panel to the chosen plane. The extensions from the stacked panels allow each panel to be rigidly connected to its revolute joint in the chosen plane with all other joints. The accommodation technique utilizes origami models that are rigidly foldable. The height of the extensions are determined by the sum of the thicknesses of all panels between its stowed panel and the chosen joint plane. Any panel thickness can be accommodated, including multiple panel thicknesses within the same mechanism. Process steps for offset panel design of origami-inspired mechanisms are presented.

A non-overconstrained variant of the Agile Eye with a special decoupled kinematics

Robotica ◽  
2013 ◽  
Vol 32 (6) ◽  
pp. 889-905 ◽  
Author(s):  
Chin-Hsing Kuo ◽  
Jian S. Dai ◽  
Giovanni Legnani
Keyword(s):  
Angular Displacement ◽  
Universal Joint ◽  
Special Configuration ◽  
End Effector ◽  
Revolute Joint ◽  
Revolute Joints ◽  
Prismatic Joints ◽  
Decoupled Motion ◽  
Orientation Mechanism ◽  
Actuated Joints

SUMMARYA non-overconstrained three-DOF parallel orientation mechanism that is kinematically equivalent to the Agile Eye is presented in this paper. The output link (end-effector) of the mechanism is connected to the base by one spherical joint and by another three identical legs. Each leg comprises of, in turns from base, a revolute joint, a universal joint, and three prismatic joints. The three lower revolute joints are active joints, while all other joints are passive ones. Based on a special configuration, some three projective angles of the end-effector coordinates are fully decoupled with respect to the input actuated joints, that is, by actuating any revolute joint the end-effector rotates in such a way that the corresponding projective angle changes with the same angular displacement. The fully decoupled motion is analyzed geometrically and proved theoretically. Besides, the inverse and direct kinematics solutions of the mechanism are provided based on the geometric reasoning and theoretical proof.

Reconfigurable Mechanisms From the Intersection of Surfaces

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
P. C. López-Custodio ◽  
J. M. Rico ◽  
J. J. Cervantes-Sánchez ◽  
G. I. Pérez-Soto
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Chain ◽  
Mobility Analysis ◽  
Revolute Joint ◽  
Revolute Joints ◽  
Reconfigurable Mechanisms ◽  
Three Degrees Of Freedom

The method of intersection of surfaces generated by kinematic dyads is applied to obtain mechanisms that are able to shift from one mode of motion to another. Then a mobility analysis shows that the singularities of the generated surfaces can be used to obtain mechanisms which can change their number of degrees-of-freedom depending on its configuration. The generator dyads are connected as usually done by a spherical pair. However, in the cases shown in this contribution the three-degrees-of-freedom of the spherical pair are not all necessary to keep the kinematic chain closed and movable, and the spherical pair can be substituted by either a pair of intersecting revolute joints or a single revolute joint. This substitution can be obtained by means of two methods presented in this contribution.

Kinematic Analysis of Foldable Plate Structures With Rolling Joints

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Cai Jianguo
Keyword(s):  
Kinematic Analysis ◽  
Plate Structures ◽  
Revolute Joints ◽  
Equal Radius ◽  
The Difference ◽  
Planar Linkages ◽  
Panel Thickness

Rolling joints, which are created by attaching two cylindrical surfaces of equal radius using two or more thin tapes or cable, are used for rigid origami considering the panel thickness. First, the concept and two implementation methods of this joint are given. Then planar linkages are chosen to study the mobility and kinematics of foldable plate structures with rolling joints. It can be found that the rolling joints preserve the full-cycle-motion of foldable plate structures. From the closure equations of linkages, the results show that the outputs of linkages with rolling joints are the same as that with traditional revolute joints if the lengths of links are equal. However, the results are different when the lengths of links are unequal. Moreover, the difference between linkages with rolling joints and revolute joints increases with an increase of the size of rolling joints.

Graphical Methods to Locate the Secondary Instant Centers of Single-Degree-of-Freedom Indeterminate Linkages

2005 ◽  
Vol 127 (2) ◽  
pp. 249-256 ◽  
Author(s):  
David E. Foster ◽  
Gordon R. Pennock
Keyword(s):  
Degree Of Freedom ◽  
Graphical Methods ◽  
Single Degree Of Freedom ◽  
Revolute Joint ◽  
Single Degree ◽  
Revolute Joints ◽  
Straight Line ◽  
Single Link ◽  
Prismatic Joints ◽  
Two Degree Of Freedom

This paper presents graphical techniques to locate the unknown instantaneous centers of zero velocity of planar, single-degree-of-freedom, linkages with kinematic indeterminacy. The approach is to convert a single-degree-of-freedom indeterminate linkage into a two-degree-of-freedom linkage. Two methods are presented to perform this conversion. The first method is to remove a binary link and the second method is to replace a single link with a pair of links connected by a revolute joint. First, the paper shows that a secondary instant center of a two-degree-of-freedom linkage must lie on a unique straight line. Then this property is used to locate a secondary instant center of the single-degree-of-freedom indeterminate linkage at the intersection of two lines. The two lines are obtained from a purely graphical procedure. The graphical techniques presented in this paper are illustrated by three examples of single-degree-of-freedom linkages with kinematic indeterminacy. The examples are a ten-bar linkage with only revolute joints, the single flier eight-bar linkage, and a ten-bar linkage with revolute and prismatic joints.

Fuzzy Logic-based Techniques for Motion Planning of a Robot Manipulator Amongst Unknown Moving Obstacles

Robotica ◽  
1992 ◽  
Vol 10 (6) ◽  
pp. 563-574 ◽  
Author(s):  
Anupam Bagchi ◽  
Himanshu Hatwal
Keyword(s):  
Motion Planning ◽  
Fuzzy Controller ◽  
Robot Manipulator ◽  
Dynamic Environment ◽  
Geometric Approach ◽  
The Body ◽  
Sensory Data ◽  
Revolute Joints ◽  
Manipulator Link ◽  
Kinematic Motion

SUMMARYAn algorithm for kinematic motion planning of redundant planar robots, having revolute joints, in an unknown dynamic environment is presented. Distance ranging sensors, mounted on the body of each manipulator link, are simulated here to estimate the proximity of an obstacle. The sensory data is analyzed through a fuzzy controller which estimates whether a collision is imminent, and if so, employs a geometric approach to compute the joint movements necessary to avoid the collision. Obstacles can sometimes move uncompromisingly in the environment attempting a deliberate collision. Strategies to deal with such cases are presented and recovery procedures to circumvent the obstacle from tight corners are suggested. Cases of link overlap have been avoided by considering each link as a body which is sensed as an obstacle by every other link of the same manipulator. Suitable examples are presented to demonstrate the algorithm.

A Computational Analysis of Error in Locating the Rotational Axes of the Tibiofemoral Joint With an Instrumented Spatial Linkage

2012 ◽  
Author(s):  
Daniel P. Bonny ◽  
Stephen M. Howell ◽  
Maury L. Hull
Keyword(s):  
Clinical Relevance ◽  
Computational Analysis ◽  
Rigid Bodies ◽  
Coordinate Systems ◽  
Revolute Joint ◽  
Tibiofemoral Joint ◽  
Revolute Joints ◽  
Flexion Extension ◽  
Analysis Of Error

A method to measure the two kinematic axes of the tibiofemoral joint, the flexion-extension (F-E) axis and longitudinal rotation (LR) axis [1], was developed by Gatti [2]. This method used an instrumented spatial linkage (ISL), a series of six instrumented revolute joints that can measure motion between two rigid bodies. While Gatti’s method demonstrated success in locating the F-E and LR axes, defining the axes and their errors using anatomically relevant coordinate systems would improve clinical relevance. While errors due to revolute joint transducer resolution were computed, errors due to nonlinearity and hysteresis in the transducers were not examined, and errors due to different applied tibiofemoral motions were not examined. Thus the objective was to computationally determine, using anatomically relevant coordinate systems, the errors in locating the F-E and LR axes due to nonlinearity and hysteresis in the revolute joint transducers for three different simulations of applied tibiofemoral motion.

On the Mobility of Single Loop N-Bar Linkage With One Prismatic Joint

2005 ◽  
Author(s):  
W. Z. Guo ◽  
R. Du ◽  
J. X. Wang
Keyword(s):  
Change Point ◽  
Open Loop ◽  
Class Iii ◽  
Revolute Joint ◽  
Single Loop ◽  
Prismatic Joint ◽  
Revolute Joints ◽  
Offset Distance ◽  
Special Cases ◽  
Prismatic Joints

Single loop N-bar linkages that contain one prismatic joint are common in engineering. This paper presents a systematical study on the mobility of this type of mechanism. It is found that this type of mechanisms can be divided into three categories: Class I, Class II and Class III. For each category, the slide reachable range is cut into different regions: Grashofian region, non-Grashofian region and change-point region. At each region, the rotation range of the revolute joint or rotatability of the linkage is able to determine based on Ting’s criteria. The characteristics charts are given to describe the rotatability condition. For active prismatic joint, the input revolute joint(s) is/are dependent in non-Grashofian region but independent in other regions. For passive prismatic joint, the revolvability of input revolute joints is dependent on the offset distance of the prismatic joint. Two special cases are illustrated with four and five bars. Examples are given to demonstrate the presented method able to cover all the cases of N-bar linkages with one or a set of adjoined prismatic joints and N-bar open-loop robotic mechanisms.

Novel 4-DOF SCARA Parallel Robot With Cylindrical Workspace

2018 ◽  
Author(s):  
Oleksandr Stepanenko ◽  
Ilian A. Bonev
Keyword(s):  
Optimal Design ◽  
Mechanism Design ◽  
Kinematic Analysis ◽  
Parallel Robot ◽  
Equal Length ◽  
The Novel ◽  
End Effector ◽  
Revolute Joints ◽  
Serial Robot

In this paper, we present a novel 4-DOF SCARA parallel robot. The 2-DOF portion of the novel robot has been proposed before and consists of an end-effector connected to the base through two legs of type RRR and one passive constraining leg of type RP, where all the base-mounted revolute joints are coaxial. Contrary to SCARA robots based on the four-bar mechanism (RRRRR), the novel robot has a fully cylindrical workspace with no voids or parallel singularities in it. The novel robot has essentially the same workspace as that of a similarly sized ceiling-mounted SCARA serial robot (RR) with links of equal length. However, the proposed robot has the advantage of having all motors mounted on the base. We present the 2-DOF portion of the robot, its kinematic analysis, and its optimal design, and finally propose a mechanism design for the 4-DOF SCARA parallel robot.

Modeling and Optimization Research of a Planar Six Bar Mechanism

2012 ◽  
Vol 215-216 ◽  
pp. 921-925
Author(s):  
Ying Wu ◽  
Xu Zhou
Keyword(s):  
Simulation Analysis ◽  
Three Dimensional ◽  
Working Process ◽  
Revolute Joint ◽  
Technical Performance ◽  
Revolute Joints ◽  
Vertical Location ◽  
Vertical Speed ◽  
Optimization Parameters ◽  
Set Up

For being convenient for researching the dynamic characteristic and the improvement and use of the planar six bar mechanism, for improving the dynamic technical performance, the three-dimensional solid model of the mechanism was established with ADAMS. Each part of the model in ADAMS was set up. Simulation analysis on the working process of the mechanism was achieved. The structure optimization parameters of the mechanism were obtained. The result proves that the vertical location of revolute joint of link and rocker, the location of revolute joint of crank and frame, the horizontal locations of two revolute joints of link are almost no impact on the vertical speed of slider. The vertical locations of revolute joint of frame and rocker and revolute joint of block and slider have less impact on the vertical speed and acceleration of slider. The vertical location of revolute joint of link and crank, the horizontal locations of revolute joint of frame and rocker and revolute joint of block and slider have greater impact on the maximum vertical speed and acceleration of slider.

An Overview of Several Formulations for Dry and Lubricated Revolute Joint Clearances in Planar Rigid-Multi-Body Mechanical Systems

2014 ◽  
Author(s):  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Numerical Models ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Revolute Joint ◽  
Coulomb’S Friction ◽  
Revolute Joints ◽  
Joint Clearances ◽  
Multi Body

The influence of the revolute joint model on the dynamic response of planar multibody mechanical systems is studied in this work. In the sequel of this process, under the framework of the multibody formalisms, a general methodology for modeling the main kinematic aspects of dry revolute joint clearances is revisited. The numerical models for normal and tangential contact forces developed at the clearance joints are also discussed, which are based on the Hertzian contact theory and dry Coulomb’s friction law, respectively. The fundamental kinematic and dynamic issues of the modeling lubricated revolute joints are presented in this work in order to compare them with the dry revolute joint approach. In a simple manner, the lubrication forces are obtained by integrating the pressure distribution evaluated with the aid of Reynolds’ equation corresponding to the dynamic regime. The intra-joint forces developed for both dry and lubricated cases are evaluated based on the state of variable of the system and subsequently included into the dynamic equations of motion of the multibody system as external generalized forces. The main assumptions and procedures adopted throughout this work are demonstrated through simulations of a planar slider-crank mechanism, which includes dry and lubricated revolute joint with clearance. Finally, some experimental data is also presented and analyzed.

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