Static Analysis for a Novel 6-(P-2P-S) Parallel Robot

2009 ◽  
Vol 69-70 ◽  
pp. 580-584 ◽  
Author(s):  
D.F. Zhang ◽  
Feng Gao
Keyword(s):  
Carrying Capacity ◽  
Simple Structure ◽  
Jacobian Matrix ◽  
Parallel Robot ◽  
Singular Value ◽  
Force Transmission ◽  
Practical Application ◽  
Positioning Device ◽  
Orientation Parameters ◽  
Orientation Workspace

A novel 6-(P-2P-S) parallel robot is put forward. With the characters of some movement decoupling on the orthogonal pose, the robot can be used as the macro manipulator of the macro/micro dual driven robots. The macro manipulator as a high-precision positioning device, it is significant for the practical application and drive train design to research statics. First, the force Jacobian matrix is deduced, which is related to the orientation parameters. Then based on the Jacobian matrix singular value decomposed characteristic, the static force transmission evaluation indicators Kf and Km are defined. Finally, considering structure constraints and parameters, the distribution of evaluation indicators in the orientation workspace is drawn, which provide the theoretical base for the design and applications of the robot. Because of the characters of simple structure, high carrying capacity, less motion inertia, good manufacturability, the 6-(P-2P-S) parallel macro manipulator has been designed.

Delta Parallel Robot Based on Crank-Slider Mechanism

2017 ◽  
Vol 6 (2) ◽  
pp. 112
Author(s):  
Zhe Qin ◽  
Xiao-Chu Liu ◽  
Zhuan Zhao
Keyword(s):  
Parallel Robot ◽  
Force Transmission ◽  
Practical Application ◽  
Cartesian Space ◽  
Output Torque ◽  
Performance Indexes ◽  
Pick And Place ◽  
Delta Robot ◽  
Three Degree Of Freedom ◽  
Pick And Place Operation

A three-degree-of-freedom Delta parallel manipulator driven by a crank-slider mechanism is proposed. In Cartesian space, a gate-shaped curve is taken as the path of the pick-and-place operation, combining with the inverse kinematics theory of the Delta robot, and a mathematical model of robot statia force transmission is established. The force and the output torque of the robot-driven joint are taken as the main performance indexes, and the value of the crank-slider mechanism applied to Delta robot is further measured. The simulation results show that the delta robot driven by the crank slider mechanism can reduce the force and output torque of the driving joint during the picking and discharging operation, and has good practical application value.

Workspace Analysis and Optimal Design of a Translational Cable-Driven Parallel Robot With Passive Springs

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Zhaokun Zhang ◽  
Zhufeng Shao ◽  
Fazhong Peng ◽  
Haisheng Li ◽  
Liping Wang
Keyword(s):  
Optimal Design ◽  
High Speed ◽  
Simple Structure ◽  
Design Method ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Force Transmission ◽  
Workspace Analysis ◽  
The Matrix ◽  
Optimal Design Method

Abstract Cable-driven parallel robots (CDPRs) have great prospects for high-speed applications because of their nature of low inertia and good dynamics. Existing high-speed CDPRs mainly adopt redundant cables to keep positive cable tensions. Redundant cables lead to complex and costly structure, and are likely to cause interference. In this study, a non-redundant CDPR for high-speed translational motions is designed with passive springs and parallel cables. First, the configuration of the CDPR is illustrated, and its kinematics and dynamics are studied. Then, the workspace of the CDPR is discussed in detail. The condition of positive cable tensions is proved. The influence of the springs’ layout on the workspace is analyzed. A method for determining the regular cylindrical operation workspace is proposed. Furthermore, the optimal design method for high-speed CDPRs with passive springs is developed. Performance indices for evaluating the force transmission are defined based on the matrix orthogonal degree. The geometric parameters are optimized based on the workspace and force transmission indices. The stiffness coefficient of the spring is determined based on the acceleration and cable tension requirements. Finally, the proposed CDPR and the traditional CDPR with redundant cables are compared through simulation. The results show that the designed CDPR possesses advantages in energy consumption and simple structure compared to CDPR with redundant cables.

scholarly journals Multi-Target Detection Method Based on Variable Carrier Frequency Chirp Sequence

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3386 ◽  
Author(s):  
Wei Wang ◽  
Jinsong Du ◽  
Jie Gao
Keyword(s):  
Intelligent Transportation Systems ◽  
Simple Structure ◽  
Low Cost ◽  
Doppler Frequency ◽  
Transportation Systems ◽  
Practical Application ◽  
Frequency Aliasing ◽  
Application Requirements ◽  
Relationship Of ◽  
Cw Radar

Continuous waveform (CW) radar is widely used in intelligent transportation systems, vehicle assisted driving, and other fields because of its simple structure, low cost and high integration. There are several waveforms which have been developed in the last years. The chirp sequence waveform has the ability to extract the range and velocity parameters of multiple targets. However, conventional chirp sequence waveforms suffer from the Doppler ambiguity problem. This paper proposes a new waveform that follows the practical application requirements, high precision requirements, and low system complexity requirements. The new waveform consists of two chirp sequences, which are intertwined to each other. Each chirp signal has the same frequency modulation, the same bandwidth and the same chirp duration. The carrier frequencies are different and there is a frequency shift which is large enough to ensure that the Doppler frequencies for the same moving target are different. According to the sign and numerical relationship of the Doppler frequencies (possibly frequency aliasing), the Doppler frequency ambiguity problem is solved in eight cases. Theoretical analysis and simulation results verify that the new radar waveform is capable of measuring range and radial velocity simultaneously and unambiguously, with high accuracy and resolution even in multi-target situations.

scholarly journals Kinematic Synthesis of Tendon-Driven Manipulators with Isotropic Transmission Characteristics

1993 ◽  
Vol 115 (4) ◽  
pp. 884-891 ◽  
Author(s):  
Yeong-Jeong Ou ◽  
Lung-Wen Tsai
Keyword(s):  
Jacobian Matrix ◽  
Null Vector ◽  
Force Distribution ◽  
Force Transmission ◽  
Transmission Characteristics ◽  
Kinematic Synthesis ◽  
End Effector ◽  
Structure Matrix ◽  
Applied Forces ◽  
Matrix Design

This paper presents a methodology for kinematic synthesis of tendon-driven manipulators with isotropic transmission characteristics. The force transmission characteristics, from the end-effector space to the actuator space, has been investigated. It is shown that tendon forces required to act against externally applied forces are functions of the structure matrix, its null vector, and the manipulator Jacobian matrix. Design equations for synthesizing a manipulator to possess isotropic transmission characteristics are derived. It is shown that manipulators which possess isotropic transmission characteristics have much better force distribution among their tendons.

scholarly journals A new technology for strengthening soils as an intangible resource for investment-building projects

2018 ◽  
Vol 212 ◽  
pp. 07001
Author(s):  
Alexander Petrov ◽  
Artem Peshkov ◽  
Ksenia Baginova
Keyword(s):  
Carrying Capacity ◽  
Construction Projects ◽  
New Technology ◽  
Soil Reinforcement ◽  
Load Carrying Capacity ◽  
Practical Application ◽  
Intellectual Activity ◽  
Building Projects ◽  
Load Carrying ◽  
Ground Conditions

The effectiveness of intellectual activity in construction is determined by the relevance and the possibility of practical application of its results in the implementation of investment and construction projects. The investment attractiveness of the territory depends to a large extent, including on the construction site’s ground conditions. Analysis of scientific research conducted by Russian and foreign researchers shows that the solution of this problem is possible due to the strengthening of soils. Areas of application of soil reinforcement technology are identified. The analysis of existing technologies carried out in the field of increasing the load-carrying capacity of soils has been carried out, and the main shortcomings of the methods have been identified. A new technology for strengthening soils with crushed stone piles is proposed. The main problems are researched, and the ways of their solution are considered in case of applying the proposed technology.

Analysis of Active Joint Failure in Parallel Robot Manipulators

2004 ◽  
Vol 126 (6) ◽  
pp. 959-968 ◽  
Author(s):  
Mahir Hassan ◽  
Leila Notash
Keyword(s):  
Jacobian Matrix ◽  
Null Space ◽  
Robot Manipulators ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Task Space ◽  
Active Joint ◽  
Joint Failure ◽  
Space Vectors ◽  
Six Degree Of Freedom

In this study, the effect of active joint failure on the mobility, velocity, and static force of parallel robot manipulators is investigated. Two catastrophic active joint failure types are considered: joint jam and actuator force loss. To investigate the effect of failure on mobility, the Gru¨bler’s mobility equation is modified to take into account the kinematic constraints imposed by various branches in the manipulator. In the case of joint jam, the manipulator loses the ability to move and apply force in a specific portion of its task space; while in the case of actuator force loss, the manipulator gains an unconstrained motion in a specific portion of the task space in which an externally applied force cannot be resisted by the actuator forces. The effect of joint jam and actuator force loss on the velocity and on the force capabilities of parallel manipulators is investigated by examining the change in the Jacobian matrix, its inverse, and transposes. It is shown that the reduced velocity and force capabilities after joint jam and loss of actuator force could be determined using the null space vectors of the transpose of the Jacobian matrix and its inverse. Computer simulation is conducted to demonstrate the application of the developed methodology in determining the post-failure trajectory of a 3-3 six-degree-of-freedom Stewart-Gough manipulator, when encountering active joint jam and actuator force loss.

Posture, Workspace, and Manipulability of the Metamorphic Multifingered Hand With an Articulated Palm

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Lei Cui ◽  
Jian S. Dai
Keyword(s):  
Jacobian Matrix ◽  
Contact Point ◽  
Gauss Map ◽  
Singular Value ◽  
Spherical Joint ◽  
Additional Dimension ◽  
Workspace Analysis ◽  
Finger Motion ◽  
Value Decomposition ◽  
Relationship Of

This paper presents a novel multifingered hand with an articulated palm that makes the hand adaptable and reconfigurable. The posture of the new multifingered hand is enhanced by the additional motion of the palm and the workspace of fingers is augmented by the palm workspace. To analyze this integrated workspace, this paper introduces finger-operation planes to relate the finger motion to the palm motion and its configuration. Normals of these operation planes are used to construct a Gauss map. Adding an additional dimension, a four-dimensional ruled surface can be generated from this map to illustrate variation of posture. With the change of palm configurations, a posture manifold can be developed from the posture ruled surfaces. The workspace analysis is developed by introducing a palm workspace-triangle. This workspace-triangle evolves into a helical workspace-triangle tube when palm inputs vary and further develops into a four-dimensional presentation. This progresses into a set of workspaces of the multifingered hand by varying the palm configuration, leading to a larger workspace of the new multifingered hand as the union of the workspaces corresponding to individual palm configuration. This paper further investigates manipulability of the multifingered hand by modeling the contact point as a hypothetical spherical joint. Based on reciprocity relationship of screw systems, the finger Jacobian matrices and the hand Jacobian matrix are established. With singular value decomposition, manipulability of each finger is explored and the hand manipulability is revealed by the diagonal nature of the Jacobian matrix of the hand.

Novel Design and Analysis of a Fully Decoupled 3-DOF Spherical Parallel Robot

2009 ◽  
Author(s):  
Dan Zhang ◽  
Fan Zhang
Keyword(s):  
Physical Meaning ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Parallel Robot ◽  
Degree Of Freedom ◽  
Redundant Constraints ◽  
Rotational Motions ◽  
Three Degree Of Freedom ◽  
Novel Design

In this paper, we propose a unique, decoupled Three Degree-of-Freedom (DOF) parallel wrist. The condition required for synthesizing a fully isotropic parallel mechanism is obtained based on the physical meaning of the row vector in the Jacobian Matrix. Specifically, an over-constrained spherical 3-DOF parallel mechanism is presented and the modified structure, which avoids the redundant constraints, is also introduced. The proposed manipulator is capable of decoupled rotational motions around the x, y and z axes and contains an output angle that is equal to the input angle. Since this device is analyzed with the Jacobian Matrix, which is constant, the mechanism is free of singularity and maintains homogenous stiffness over the entire workspace.

Singularity Analysis of a Novel 4-DOFs Parallel Robot H4 by Using Screw Theory

2003 ◽  
Author(s):  
Hee-Byoung Choi ◽  
Atsushi Konno ◽  
Masaru Uchiyama
Keyword(s):  
Closed Loop ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Parallel Robot ◽  
Singularity Analysis ◽  
Loop Structure ◽  
Singular Configurations ◽  
Planning And Control ◽  
Kinematic Singularities ◽  
And Control

The closed-loop structure of a parallel robot results in complex kinematic singularities in the workspace. Singularity analysis become important in design, motion, planning, and control of parallel robot. The traditional method to determine a singular configurations is to find the determinant of the Jacobian matrix. However, the Jacobian matrix of a parallel manipulator is complex in general, and thus it is not easy to find the determinant of the Jacobian matrix. In this paper, we focus on the singularity analysis of a novel 4-DOFs parallel robot H4 based on screw theory. Two types singularities, i.e., the forward and inverse singularities, have been identified.

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