Theory of Isotropic Transmission for Tendon-Driven Manipulators

1994 ◽  
Author(s):  
Yeong-Jeong Ou ◽  
Lung-Wen Tsai
Keyword(s):  
General Theory ◽  
Power Transmission ◽  
Degree Of Freedom ◽  
Mechanical Power ◽  
Force Distribution ◽  
Static Force ◽  
Force Transmission ◽  
Transmission Characteristics ◽  
End Effector ◽  
Transmission Structure

Abstract This paper deals with the synthesis of the mechanical power transmission structure in tendon-driven manipulators. Based on the analysis of static force transmission from the actuator space to the end-effector space, a general theory is developed for the synthesis of tendon-driven manipulators with isotropic transmission characteristics. It is shown that an n-dof (degree of freedom) manipulator can possess these characteristics if it is made up of n+1 or 2n tendons and if its link lengths and pulley sizes are designed according to two equations of constraint. Two examples are used to demonstrate the theory. It is also shown that manipulators with an isotropic transmission structure do have more uniform force distribution among their tendons.

scholarly journals Isotropic Design of Tendon-Driven Manipulators

1996 ◽  
Vol 118 (3) ◽  
pp. 360-366 ◽  
Author(s):  
Yeong-Jeong Ou ◽  
Lung-Wen Tsai
Keyword(s):  
Necessary Conditions ◽  
Degree Of Freedom ◽  
Mechanical Transmission ◽  
Force Distribution ◽  
Static Force ◽  
Design Equation ◽  
Force Analysis ◽  
Transmission Characteristics ◽  
Transmission Structure ◽  
Tendon Force

This paper deals with the synthesis of mechanical transmission structures for tendon-driven manipulators. Based on static force analysis, necessary conditions are developed for the synthesis of tendon-driven manipulators with isotropic transmission characteristics. It is shown that an n degree-of-freedom (dof) manipulator will possess the isotropic transmission characteristics, if it satisfies two isotropic conditions. Furthermore, a design equation is derived for the construction of isotropic transmission structure matrices and a three-dof spatial manipulator is synthesized to demonstrate the methodology. It is shown that the isotropic design leads to a more uniform tendon force distribution.

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 Kinematic Synthesis of Tendon-Driven Manipulators With Isotropic Transmission Characteristics

1993 ◽  
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

Abstract 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 do have much better force distribution among their tendons.

Modeling and Analysis of the Transmission Characteristics of a Geared Linkage Mechanism

2011 ◽  
Vol 311-313 ◽  
pp. 1475-1480
Author(s):  
Wei Yang Zhang ◽  
Cun Yun Pan ◽  
Hao Deng ◽  
Hai Jun Xu ◽  
Hu Chen
Keyword(s):  
Power Transmission ◽  
Force Transmission ◽  
Linkage Mechanism ◽  
Transmission Characteristics ◽  
Modeling And Analysis ◽  
Rotation Direction ◽  
Transmission Equipment ◽  
Torque Transmission ◽  
Transmission Angle ◽  
Output Component

Twin-rotor piston engine is exceedingly compact, and several times more power dense than conventional IC engines. It is necessary to analyze the transmission characteristics of the special geared linkage mechanism which is used for the power transmission equipment of the engine. Transmission angle is mainly adopted in order to obtain the transmission characteristics. Firstly, the force transmission behavior of one end of the output component is derived through the force analysis of the planet gear. Secondly, the torque transmission angle is proposed based on the multi-point force situation. Lastly, the torque transmission angle is depicted and analyzed in detail through the equivalent composite force graphical method. The result shows that the geared linkage mechanism will not produce counteractive torque to the rotation direction and has no dead point.

Direct Differential Kinematics of Hybrid-Chain Manipulators Including Singularity and Stability Analyses

1994 ◽  
Vol 116 (2) ◽  
pp. 614-621 ◽  
Author(s):  
Yong-Xian Xu ◽  
D. Kohli ◽  
Tzu-Chen Weng
Keyword(s):  
Stability Index ◽  
Inverse Kinematic ◽  
Degree Of Freedom ◽  
Static Force ◽  
Force Analysis ◽  
Kinematic Singularity ◽  
Numerical Examples ◽  
Transformation Matrices ◽  
Unstable Configuration ◽  
Direct Kinematics

A general formulation for the differential kinematics of hybrid-chain manipulators is developed based on transformation matrices. This formulation leads to velocity and acceleration analyses, as well as to the formation of Jacobians for singularity and unstable configuration analyses. A manipulator consisting of n nonsymmetrical subchains with an arbitrary arrangement of actuators in the subchain is called a hybrid-chain manipulator in this paper. The Jacobian of the manipulator (called here the system Jacobian) is a product of two matrices, namely the Jacobian of a leg and a matrix M containing the inverse of a matrix Dk, called the Jacobian of direct kinematics. The system Jacobian is singular when a leg Jacobian is singular; the resulting singularity is called the inverse kinematic singularity and it occurs at the boundary of inverse kinematic solutions. When the Dk matrix is singular, the M matrix and the system Jacobian do not exist. The singularity due to the singularity of the Dk matrix is the direct kinematic singularity and it provides positions where the manipulator as a whole loses at least one degree of freedom. Here the inputs to the manipulator become dependent on each other and are locked. While at these positions, the platform gains at least one degree of freedom, and becomes statically unstable. The system Jacobian may be used in the static force analysis. A stability index, defined in terms of the condition number of the Dk matrix, is proposed for evaluating the proximity of the configuration to the unstable configuration. Several illustrative numerical examples are presented.

Three-Degree-of-Freedom Parallel Robot Arm

2006 ◽  
Author(s):  
Martin Hosek ◽  
Michael Valasek ◽  
Jairo Moura
Keyword(s):  
Parallel Robot ◽  
Degree Of Freedom ◽  
Motion Path ◽  
Angular Orientation ◽  
Robot Arm ◽  
Flat Panel Display ◽  
End Effector ◽  
Cluster Tools ◽  
Manufacturing Applications ◽  
Three Degree Of Freedom

This paper presents single- and dual-end-effector configurations of a planar three-degree of freedom parallel robot arm designed for automated pick-place operations in vacuum cluster tools for semiconductor and flat-panel-display manufacturing applications. The basic single end-effector configuration of the arm consists of a pivoting base platform, two elbow platforms and a wrist platform, which are connected through two symmetric pairs of parallelogram mechanisms. The wrist platform carries an end-effector, the position and angular orientation of which can be controlled independently by three motors located at the base of the robot. The joints and links of the mechanism are arranged in a unique geometric configuration which provides a sufficient range of motion for typical vacuum cluster tools. The geometric properties of the mechanism are further optimized for a given motion path of the robot. In addition to the basic symmetric single end-effector configuration, an asymmetric costeffective version of the mechanism is derived, and two dual-end-effector alternatives for improved throughput performance are described. In contrast to prior attempts to control angular orientation of the end-effector(s) of the conventional arms employed currently in vacuum cluster tools, all of the motors that drive the arm can be located at the stationary base of the robot with no need for joint actuators carried by the arm or complicated belt arrangements running through the arm. As a result, the motors do not contribute to the mass and inertia properties of the moving parts of the arm, no power and signal wires through the arm are necessary, the reliability and maintenance aspects of operation are improved, and the level of undesirable particle generation is reduced. This is particularly beneficial for high-throughput applications in vacuum and particlesensitive environments.

Force Capabilities of Two-Degree-of-Freedom Serial Robots Equipped With Passive Isotropic Force Limiters

2015 ◽  
Author(s):  
Meiying Zhang ◽  
Thierry Laliberté ◽  
Clément Gosselin
Keyword(s):  
Human Robot Interaction ◽  
Contact Forces ◽  
Degree Of Freedom ◽  
Practical Implementation ◽  
Robot Interaction ◽  
End Effector ◽  
Serial Robots ◽  
Serial Robot ◽  
Maximum Contact ◽  
Two Degree Of Freedom

This paper proposes the use of passive force and torque limiting devices to bound the maximum forces that can be applied at the end-effector or along the links of a robot, thereby ensuring the safety of human-robot interaction. Planar isotropic force limiting modules are proposed and used to analyze the force capabilities of a two-degree-of-freedom planar serial robot. The force capabilities at the end-effector are first analyzed. It is shown that, using isotropic force limiting modules, the performance to safety index remains excellent for all configurations of the robot. The maximum contact forces along the links of the robot are then analyzed. Force and torque limiters are distributed along the structure of the robot in order to ensure that the forces applied at any point of contact along the links are bounded. A power analysis is then presented in order to support the results. Finally, examples of mechanical designs of force/torque limiters are shown to illustrate a possible practical implementation of the concept.

Sign in / Sign up

Export Citation Format

Share Document