Analysis of a mechanism with redundant drive for antenna pointing

2016 ◽  
Vol 231 (2) ◽  
pp. 229-239 ◽  
Author(s):  
Xin Li ◽  
Xilun Ding ◽  
Gregory S Chirikjian
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Numerical Examples ◽  
Pointing Device ◽  
Key Factor ◽  
Rotary Motors ◽  
Redundantly Actuated ◽  
Pointing Accuracy ◽  
Forward And Inverse Kinematics ◽  
Redundant Drive

Orientation accuracy is a key factor in the design of mechanisms for antenna pointing. Our design uses a redundantly actuated parallel mechanism which may provide an effective way to solve this problem, and even can increase its payload capability and reliability. The presented mechanism can be driven by rotary motors fixed on the base to reduce the inertia of the moving parts and to lower the power consumption. The mechanism is redundantly actuated by three arms, and is used as a two-dimensional antenna tracking and pointing device. Both the forward and inverse kinematics are investigated to find all the possible solutions. Detailed characters of the platform are analyzed to demonstrate the advantages in eliminating singularities and improving pointing accuracy. A method of calculating the overconstrained orientational error is also proposed based on the differential kinematics. All the methods are verified by numerical examples.

scholarly journals Stability and Gait Planning of 3-UPU Hexapod Walking Robot

Robotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 48 ◽  
Author(s):  
Ruiqin Li ◽  
Hongwei Meng ◽  
Shaoping Bai ◽  
Yinyin Yao ◽  
Jianwei Zhang
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Step Length ◽  
Parallel Robot ◽  
Search Method ◽  
Walking Robot ◽  
Gait Control ◽  
Gait Planning ◽  
Forward And Inverse Kinematics ◽  
Passing Ability

The paper presents an innovative hexapod walking robot built with 3-UPU parallel mechanism. In the robot, the parallel mechanism is used as both an actuator to generate walking and also a connecting body to connect two groups of three legs, thus enabling the robot to walk with simple gait by very few motors. In this paper, forward and inverse kinematics solutions are obtained. The workspace of the parallel mechanism is analyzed using limit boundary search method. The walking stability of the robot is analyzed, which yields the robot’s maximum step length. The gait planning of the hexapod walking robot is studied for walking on both flat and uneven terrains. The new robot, combining the advantages of parallel robot and walking robot, has a large carrying capacity, strong passing ability, flexible turning ability, and simple gait control for its deployment for uneven terrains.

scholarly journals Design and Analysis of a Novel Tree Climbing Robot Mechanism

2020 ◽  
Author(s):  
Ru-Gui Wang ◽  
Hai-Bo Huang ◽  
Yi Li ◽  
Ji-Wei Yuan
Keyword(s):  
Numerical Simulation ◽  
Physical Model ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Singular Points ◽  
Climbing Robot ◽  
Overall Design ◽  
Forward And Inverse Kinematics ◽  
The Relationship

Abstract In this paper, a novel tree climbing robot mechanism was designed, based on the tree climbing movement and posture of the primates. The overall design and tree climbing gait of the tree climbing robot were analyzed in detail. According to the screw theory, the DOF of the leg of the tree climbing robot is calculated. The forward and inverse kinematics equations of the tree climbing robot were established and solved. The kinematics of the leg parallel mechanism was established, furthermore, the singularity of the leg mechanism was analyzed and three types of singularity were derived. The simplified diagrams and the corresponding model diagrams, at the singular points, were drawn. Finally, the movement is simulated and analyzed. And the changes of the leg joint angular and the foot-end displacement and the relationship between the driving displacement and angles of the tree climbing robot by numerical simulation is obtained at the same time. Prototype physical model of the tree climbing robot was made, which further verified the rationality and feasibility of the tree climbing robot mechanism studied in this paper.

Kinematics of a planar slider-crank linkage in screw form

2021 ◽  
pp. 095440622110207
Author(s):  
Jing-Shan Zhao ◽  
Songtao Wei ◽  
Junjie Ji
Keyword(s):  
Angular Velocity ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Numerical Algorithms ◽  
Forward Kinematics ◽  
End Effector ◽  
First Order ◽  
Forward And Inverse Kinematics ◽  
Definition Of ◽  
Inverse Velocity

This paper investigates the forward and inverse kinematics in screw coordinates for a planar slider-crank linkage. According to the definition of a screw, both the angular velocity of a rigid body and the linear velocity of a point on it are expressed in screw components. Through numerical integration on the velocity solution, we get the displacement. Through numerical differential interpolation of velocity, we gain the acceleration of any joint. Traditionally, position and angular parameters are usually the only variables for establishing the displacement equations of a mechanism. For a series mechanism, the forward kinematics can be expressed explicitly in the variable of position parameters while the inverse kinematics will have to resort to numerical algorithms because of the multiplicity of solution. For a parallel mechanism, the inverse kinematics can be expressed explicitly in the variable of position parameters of the end effector while the forward kinematics will have to resort to numerical algorithms because of the nonlinearity of system. Therefore this will surely lead to second order numerical differential interpolation for the calculation of accelerations. The most prominent merit of this kinematic algorithm is that we only need the first order numerical differential interpolation for computing the acceleration. To calculate the displacement, we also only need the first order numerical integral of the velocity. This benefit stems from the screw the coordinates of which are velocity components. The example of planar four-bar and five-bar slider-crank linkages validate this algorithm. It is especially suited to developing numerical algorithms for forward and inverse velocity, displacement and acceleration of a linkage.

scholarly journals Mathematical Modeling, Design Validation, and Simulation of Morphing Mechanism for Winglet Applications

2021 ◽  
Author(s):  
Upasana Choudhuri
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
System Response ◽  
Preliminary Design ◽  
Kinematic Modeling ◽  
System Operation ◽  
Design Validation ◽  
Velocity Models ◽  
Redundantly Actuated ◽  
Inverse Velocity

Presented within this thesis is the preliminary design phases for the development of a morphing winglet mechanism. The mathematical models and analyses conducted within this thesis provide the means for bringing the design concept stage to the testing and validation phases. The kinematic modeling of a proposed design is developed. The inverse kinematics of the system are used to determine the required inputs to meet the range of motion. The velocity models for the system are established for both the forward and inverse cases. The inverse velocity models are used to establish a synchronous behaviour between the two serial linkages. Thus, allowing system operation as a redundantly actuated parallel mechanism. The results of implementation are evaluated for the initial and optimized designs. A proposed velocity profile is developed to facilitate control and desired operation of the system. This is then validated by the testing of the system response and error.

scholarly journals Mathematical Modeling, Design Validation, and Simulation of Morphing Mechanism for Winglet Applications

2021 ◽  
Author(s):  
Upasana Choudhuri
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
System Response ◽  
Preliminary Design ◽  
Kinematic Modeling ◽  
System Operation ◽  
Design Validation ◽  
Velocity Models ◽  
Redundantly Actuated ◽  
Inverse Velocity

Presented within this thesis is the preliminary design phases for the development of a morphing winglet mechanism. The mathematical models and analyses conducted within this thesis provide the means for bringing the design concept stage to the testing and validation phases. The kinematic modeling of a proposed design is developed. The inverse kinematics of the system are used to determine the required inputs to meet the range of motion. The velocity models for the system are established for both the forward and inverse cases. The inverse velocity models are used to establish a synchronous behaviour between the two serial linkages. Thus, allowing system operation as a redundantly actuated parallel mechanism. The results of implementation are evaluated for the initial and optimized designs. A proposed velocity profile is developed to facilitate control and desired operation of the system. This is then validated by the testing of the system response and error.

Kinematic Modeling of a Novel RR-RP Hybrid Serial-Parallel Mechanism With Variable Topology

2021 ◽  
Author(s):  
Brian J. Slaboch ◽  
Peter Holtzen ◽  
Luis A. Rodriguez
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Lower Cost ◽  
Velocity Analysis ◽  
Kinematic Modeling ◽  
Efficient Mechanism ◽  
Lower Weight ◽  
Workspace Analysis ◽  
Variable Topology ◽  
Forward And Inverse Kinematics

Abstract This paper introduces a new mechanism that will be classified as an RR-RP hybrid serial-parallel mechanism with variable topology. A mechanism with variable topology is a mechanism that can change its topology due to a change it its joints constraint geometric profile. The RR-RP is unique in that it combines the functionality of both an RR and RP serial manipulator without the need for an additional actuator, leading to a lower weight, lower cost, and more efficient mechanism. The new mechanism and its topology are presented, followed by a workspace analysis, derivation of the forward and inverse kinematics, and velocity analysis of the new mechanism.

Kinematic Analysis of a Three-DOF Parallel Mechanism for Telescope Applications

1997 ◽  
Author(s):  
J. A. Carretero ◽  
M. Nahon ◽  
B. Buckham ◽  
C. M. Gosselin
Keyword(s):  
Kinematic Analysis ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Constraint Equations ◽  
Forward And Inverse Kinematics ◽  
Position And Orientation ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom

Abstract This paper presents a kinematic analysis of a three-degree-of-freedom parallel mechanism intended for use as a telescope mirror focussing device. The construction of the mechanism is first described and its forward and inverse kinematics solutions are derived. Because the mechanism has only three degrees of freedom, constraint equations must be generated to describe the inter-relationship between the six Cartesian coordinates which describe the position and orientation of the moving platform. Once these constraints are incorporated into the kinematics model, a constrained Jacobian matrix is obtained. The stiffness and dexterity properties of the mechanism are then determined based on this Jacobian matrix. The mechanism is shown to exhibit desirable properties in the region of its workspace of interest in the telescope focussing application.

Kinematics and Singularity Analysis of a 2R2T Parallel Mechanism

2015 ◽  
Author(s):  
Wei Ye ◽  
Yuefa Fang ◽  
Sheng Guo
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Singularity Analysis ◽  
Design Stage ◽  
Forward Kinematics ◽  
Medical Applications ◽  
Moving Platforms ◽  
Forward And Inverse Kinematics ◽  
Displacement Group

In this paper, we focus our attention on a parallel mechanism with four identical limbs and two moving platforms that are connected by a prismatic joint. Firstly, the degrees of freedom analysis of the mechanism is conducted based on the displacement group theory. Both the two moving platforms have the ability to perform two rotational and two translational motions (2R2T). Secondly, forward and inverse kinematics of the proposed mechanism is analyzed, closed-from solutions are obtained for the forward kinematics. Finally, three types of singularity, i.e. limb singularity, actuation singularity and platform singularity of the 2R2T parallel mechanism are analyzed. No limb singularity and platform singularity is found and the actuation singularity can be avoided in the design stage. The proposed mechanism has the potential to be used in industry and medical applications.

Design, Modeling and Kinematics Analysis of a Novel Serial/Parallel Pole Climbing and Manipulating Robot

Volume 2 ◽  
2004 ◽  
Author(s):  
G. R. Vossoughi ◽  
S. Bagheri ◽  
M. Tavakoli ◽  
M. R. Zakerzadeh ◽  
M. Hosseinzadeh
Keyword(s):  
Cross Section ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Main Part ◽  
Target Point ◽  
Tubular Structures ◽  
Kinematics Analysis ◽  
Kinematics Model ◽  
Workspace Analysis ◽  
Forward And Inverse Kinematics

This paper introduces a multi-task 4 DOF pole climbing/manipulating robotic mechanism. A hybrid serial/parallel mechanism, providing 2 translations and 2 rotations, have been designed as the main part of the mechanism. This robotic mechanism can travel along tubular structures with bends, branches and step changes in cross section. It is also able to perform manipulation, repair and maintenance tasks after reaching the target point on the structure. After introducing the mechanism, a kinematics model and the forward and inverse kinematics as well as the workspace analysis of the mechanism are presented.

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