scholarly journals Research of Kinematic Stepping Mechanism

2021 ◽  
Vol 58 (5) ◽  
pp. 63-72
Author(s):  
I. Grinevich ◽  
V. Nikishin ◽  
G. Springis
Keyword(s):  
Kinematic Analysis ◽  
Optimality Criterion ◽  
Vertical Plane ◽  
Classical Trajectory ◽  
Step Height ◽  
Output Link ◽  
Step Cycle ◽  
The Given

Abstract In this paper, a kinematic analysis of Theo Jansen’s stepping mechanism has been carried out and an algorithm for finding the output link trajectory from the given dimensions of the stepping mechanism elements, implemented by Mathcad program, has been developed. It is possible to output characterising parameters of all intermediate links with any number of intermediate links of a step cycle of the mechanism. The dimensions of the mechanism elements have been selected so that they provide the optimal smooth trajectory of the stepping point, minimising the mechanism oscillations in the vertical plane. A comparison of the trajectories of the foot in this study with the classical trajectory of Theo Jansen and the trajectory from article [7] has been provided. A minimum swing of the oscillation of the centre of mechanism masses in the vertical plane has been selected as an optimality criterion, combined with the maximum smoothness of the trajectory, provided that maximization of the step height is not required.

Computing Model for Vibratory Digging-Out of Sugar Beet Roots

2014 ◽  
Vol 1 (2) ◽  
pp. 52-60
Author(s):  
V. Bulgakov ◽  
V. Adamchuk ◽  
H. Kaletnyk
Keyword(s):  
Differential Equations ◽  
Sugar Beet ◽  
Vertical Plane ◽  
Forward Motion ◽  
Admissible Velocity ◽  
Beet Root ◽  
Optimum Speed ◽  
Analytical Research ◽  
Sugar Beet Root ◽  
The Given

The new design mathematical model of the sugar beet roots vibration digging-out process with the plowshare vibration digging working part has been created. In this case the sugar beet root is simulated as a solid body , while the plowshare vibration digging working part accomplishes fl uctuations in the longitudinal - vertical plane with the given amplitude and frequency in the process of work . The aim of the current research has been to determine the dependences between the design and kinematic parameters of the sugar beet roots vibra- tion digging-out technological process from soil , which provide the ir non-damage. Methods . For the aim ac- complishment, the methods of design mathematical models constructing based on the classical laws of me- chanics are applied. The solution of the obtained differential equations is accomplished with the PC involve- ment. Results . The differential equations of the sugar beet root’s motion in course of the vibration digging-out have been comprised . They allow to determine the admissible velocity of the vibration digging working part’s forward motion depending on the angular parameters of the latter. In the result of the computational simula- tion i.e., the solution of the obtained analytical dependence by PC, the graphic dependences of the admissible velocity of plowshare v ibration digging working part’s forward motion providing the extraction of the sugar beet root from soil without the breaking-off of its tail section have been determined. Conclusions . Due to the performed analytical research , it has been established that γ = 13 ... 16 ° , β = 20 ... 30 ° should be considered as the most reasonable values of γ and β angles of the vibration digging working part providing both its forward motion optimum speed and sugar beet root digging-out from the soil without damage . On the ground of the data obtained from the analytical rese arch, the new vibration digging working parts for the sugar beet roots have been designed; also the patents of Ukraine for the inventions have been obtained for them.

ON THE HYBRID-DRIVEN LINKAGE MECHANISM WITH ONE INPUT CYCLE CORRESPONDING TO TWO OUTPUT CYCLES

2015 ◽  
Vol 39 (3) ◽  
pp. 637-646
Author(s):  
Ren-Chung Soong
Keyword(s):  
Kinematic Analysis ◽  
Angular Speed ◽  
Motion Trajectory ◽  
Dimensional Synthesis ◽  
Reciprocating Motion ◽  
Linkage Mechanism ◽  
Output Link ◽  
Input And Output ◽  
Single Input ◽  
Selection Of

A hybrid-driven five-bar linkage mechanism with one input cycle corresponding to two output cycles is presented. The proposed linkage mechanism is driven by a constant-speed motor and a linear motor, respectively. The output link can generate two same required output cycles during a single input cycle, while the rotational input link rotates with a constant angular speed, and the linear input link follows a reciprocating motion along a specified linear guide fixed on the rotational input link. The configuration, displacement relationship between the input and output links, and conditions of mobility of this proposed mechanism were studied, and a kinematic analysis was performed. The selection of the instantaneous motion trajectory of the linear input link and an optimal dimensional synthesis are also described. An example is provided to verify the feasibility and effectiveness of this methodology.

scholarly journals KINEMATICS OF METALLURGICAL CUTTERS WITH PARALLEL BLADES

2019 ◽  
Vol 62 (4) ◽  
pp. 308-314
Author(s):  
I. V. Bychkov ◽  
L. T. Dvornikov ◽  
I. A. Zhukov
Keyword(s):  
Cutting Force ◽  
Kinematic Analysis ◽  
Metal Cutting ◽  
Vertical Plane ◽  
Special Method ◽  
Kinematic Scheme ◽  
Maximal Force ◽  
Metal Separation ◽  
Entire Thickness ◽  
Roller Bed

Cutting with parallel blades cutters consists of three periods: blades ridging in metal; cutting; chipping (separation). Maximum force is required at the end of the ridging period and at the beginning of cutting. Since one of the blades is stationary, the second blade in cutting process has to go deep into the entire thickness of metal to cut the billet. For example, if thickness of metal is20 mm, then the upper blade needs to pass20 mmfor its cutting. If you make both blades moving towards each other, cutting effort will be less. In this case, each blade cutting20 mmof metal will pass 10mm. In order not to make mechanism of cutter with two movable blades too complicated, it is important to ensure its mobility from one drive. So, there acute the issue of arrangement possibility of blades moving towards each other with guaranteed strength of the units, transmitting effort on the blades. Kinematic scheme of cutters with blades moving parallel to each other in a vertical plane is proposed. Advantages of the proposed cutters design are the following: counter movement of blades requires less effort to cut the billet; force from each blade is distributed to two connecting rods, reducing load on each of them; since blades move towards each other, the main cutting force is distributed along the units of the mechanism and is transmitted to the engine, which reduces load on the frame and foundation when cutting; when blades move towards each other, metal separation occurs faster, it allows to concentrate maximal force during cutting with minimal load on the engine; the cut part of the billet does not fall below the roller bed at the end of cutting, so installation of the lower movable table is not required. Mobility of the proposed mechanism is determined by P.L. Chebyshev formula with its value = 1. Kinematic analysis of blades is carried out using a special method, which is in using point of connecting rods intersection.

Kinematic Analysis and Synthesis of Three-Input, Eight-Bar Mechanisms Driven by Relatively Small Cranks

1992 ◽  
Author(s):  
Kambiz Farhang ◽  
Partha Sarathi Basu
Keyword(s):  
Nonlinear Equations ◽  
Kinematic Analysis ◽  
Linear Equations ◽  
Output Link ◽  
Analysis And Design ◽  
Constraint Equations ◽  
Analysis And Synthesis ◽  
The Mean ◽  
Approximate Equations

Abstract Approximate kinematic equations are developed for the analysis and design of three-input, eight-bar mechanisms driven by relatively small cranks. Application of a method in which an output link is presumed to be comprised of a mean and a perturbational motions, along with the vector loop approach facilitates the derivation of the approximate kinematic equations. The resulting constraint equations are, (i) in the form of a set of four nonlinear equations relating the mean link orientations, and (ii) a set of four linear equations in the unknown perturbations (output link motions). The latter set of equations is solved, symbolically, to obtain the output link motions. The approximate equations are shown to be effective in the synthesis of three-input, small-crank mechanisms.

Reverse Kinematic Analysis of the Spatial Six Axis Robotic Manipulator With Consecutive Joint Axes Parallel

2007 ◽  
Author(s):  
Javier Rolda´n Mckinley ◽  
Carl Crane ◽  
David B. Dooner
Keyword(s):  
Kinematic Analysis ◽  
Closed Loop ◽  
Degree Of Freedom ◽  
Repetitive Motion ◽  
Spatial Mechanism ◽  
Joint Axis ◽  
Specific Geometry ◽  
Noncircular Gears ◽  
Six Degree Of Freedom ◽  
The Given

This paper introduces a reconfigurable one degree-of-freedom spatial mechanism that can be applied to repetitive motion tasks. The concept is to incorporate five pairs of noncircular gears into a six degree-of-freedom closed-loop spatial chain. The gear pairs are designed based on the given mechanism parameters and the user defined motion specification of a coupler link of the mechanism. It is shown in the paper that planar gear pairs can be used if the spatial closed-loop chain is comprised of six pairs of parallel joint axes, i.e. the first joint axis is parallel to the second, the third is parallel to the fourth, …, and the eleventh is parallel to the twelfth. This paper presents the detailed reverse kinematic analysis of this specific geometry. A numerical example is presented.

Optimization of Mechanism Timing Using Noncircular Gearing

1992 ◽  
Author(s):  
Judd Bernard
Keyword(s):  
Input Function ◽  
Linear Displacement ◽  
Degree Of Freedom ◽  
Output Link ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Noncircular Gears ◽  
The Given ◽  
Crank Mechanism

Abstract A single degree of freedom mechanism whose input link is a crank driven through continuous revolutions will generate output motions dependent upon the inherent mechanism geometry. For example, the slider of a slider-crank mechanism has a linear displacement (the output motion) as a function of the crank rotation (input). Only within the realm of link proportioning can the slider crank output-input function be altered. In this investigation, the continuously rotating crank of a mechanism is rigidly attached to a gear which is one of a pair of externally meshing noncircular gears. By using noncircular gears, it will be shown that the output motion of the given mechanism can be correlated to the rotation of the mating gear to which the crank is not attached. In this fashion, the output link can then be made to execute its motion according to any prescribed law. The above technique has been implemented for the cases of a crank and rocker mechanism and a slider-crank mechanism.

Kinematic Analysis of a Belt Mechanism with a Circular Eccentric Output Element

2012 ◽  
Vol 162 ◽  
pp. 11-18 ◽  
Author(s):  
Dan Perju ◽  
Erwin Christian Lovasz ◽  
Karl Heinz Modler ◽  
Cristian Moldovan ◽  
Iosif Carabas
Keyword(s):  
Kinematic Analysis ◽  
Cam Mechanism ◽  
Incremental Method ◽  
Output Element ◽  
The Given ◽  
Different Order

The paper proposes two methods for kinematic analysis of a belt mechanism with circular eccentric output element (link). One of them is based on the mechanisms geometry and the second on its kinematics in order to obtain the transmission functions of different order. Both approaches are based on a imaginary cam mechanism instantaneous isokinetic with the given belt mechanism. The transmission functions obtained by means of proposed procedures are in a numerical form due to the finite incremental method used in solving the problem.

scholarly journals A Reconfiguration Algorithm for the Single-Driven Hexapod-Type Parallel Mechanism

Robotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Alexey Fomin ◽  
Anton Antonov ◽  
Victor Glazunov
Keyword(s):  
Mechanism Design ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Virtual Prototype ◽  
Effective Algorithm ◽  
Output Link ◽  
Suggested Algorithm ◽  
Specific Output

This paper presents a hexapod-type reconfigurable parallel mechanism that operates from a single actuator. The mechanism design allows reproducing diverse output link trajectories without using additional actuators. The paper provides the kinematic analysis where the analytical relationships between the output link coordinates and actuated movement are determined. These relations are used next to develop an original and computationally effective algorithm for the reconfiguration procedure. The algorithm enables selecting mechanism parameters to realize a specific output link trajectory. Several examples demonstrate the implementation of the proposed techniques. CAD simulations on a mechanism virtual prototype verify the correctness of the suggested algorithm.

Automated 3D Fixture Layout Design

1999 ◽  
Author(s):  
Michael Yu Wang
Keyword(s):  
Optimality Criterion ◽  
Experiment Design ◽  
Layout Design ◽  
Positioning Error ◽  
New Approach ◽  
Fixture Layout ◽  
Form Closure ◽  
Interchange Algorithm ◽  
Optimal Pursuit ◽  
The Given

Abstract This paper presents a new approach to the problem of fixture layout design for 3D workpieces. The approach is based on a concept of optimum experiment design, and the problem is treated as an optimal pursuit to select optimal locators from an initial collection of a large number of fixel locations on the surfaces of the given workpiece and to achieve form-closure for the part. An interchange algorithm is described, in which the fixture locators are generated sequentially first and are further improved. The algorithm uses the D-optimality criterion to minimize the workpiece positioning error. An example of a 3D workpiece is presented to illustrate the effectiveness of the proposed approach.

Kinematical Analysis of Slide Lever Linkage of 3rd Class

2013 ◽  
Vol 432 ◽  
pp. 133-138
Author(s):  
Elena Gebel ◽  
Vasiliy Khomchenko
Keyword(s):  
Output Link ◽  
Parametric Synthesis ◽  
Kinematical Analysis ◽  
Quality Of Motion ◽  
The Given

Positioning problem is considered for the 3rd class lever linkage with dwell of the output link according to the given cyclogram and slider guide position. Using parametric synthesis and selected parameters of the 3rd class mechanism the kinematical analysis is carried out. The calculated parameters of velocity and acceleration provide quality of motion within limitations. This gives opportunity to use the mechanism in automatic machines.

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