Dynamics and control of parallel manipulators with actuation redundancy

2001 ◽  
Author(s):  
Hui Cheng
Keyword(s):  
Parallel Manipulators ◽  
Actuation Redundancy ◽  
Dynamics And Control ◽  
And Control

Planar Cable-Direct-Driven Robots: Part II — Dynamics and Control

2001 ◽  
Author(s):  
Paolo Gallina ◽  
Aldo Rossi ◽  
Robert L. Williams
Keyword(s):  
Mass Matrix ◽  
Tracking Error ◽  
Companion Paper ◽  
Current Paper ◽  
Dynamics Model ◽  
Actuation Redundancy ◽  
Dynamics And Control ◽  
And Control ◽  
Cable Tracking ◽  
Acceleration Term

Abstract A hybrid parallel/serial manipulator architecture was introduced in a companion paper where the translational freedoms are provided by a cable-direct-driven robot (CDDR) and the rotational freedoms are provided by a serial wrist mechanism. While the companion paper presents kinematics and statics, the current paper presents a dynamics model and simulated control for planar CDDRs. Examples are presented to compare the planar 3-cable CDDR with one degree of actuation redundancy and the 4-cable CDDR with two degrees of actuation redundancy. It was found that the 4-cable tracking error was worse than for the 3-cable case, due to increased inertia with an additional actuator. Also, the controller architecture considers including and not including a feedforward reference acceleration term with the overall mass matrix; the performance of the controller with the feedforward term is clearly preferable.

Forward and Inverse Acceleration Analyses of In-Parallel Manipulators

1998 ◽  
Vol 122 (3) ◽  
pp. 299-303 ◽  
Author(s):  
Jose´ Marı´a Rico Martı´nez ◽  
Joseph Duffy
Keyword(s):  
Parallel Manipulator ◽  
Computing Time ◽  
Parallel Manipulators ◽  
Simple Expression ◽  
Intermediate Step ◽  
Simple Method ◽  
Dynamics And Control ◽  
Klein Form ◽  
Six Degree Of Freedom ◽  
And Control

Simple expressions for the forward and inverse acceleration analyses of a six degree of freedom in-parallel manipulator are derived. The expressions are obtained by firstly computing the “accelerator” for a single Hooke-Prismatic-Spheric, HPS for short, connector chain in terms of the joint velocities and accelerations. The accelerator is a function of the line coordinates of the joint axes and of a sequence of Lie products of the same line coordinates. A simple expression for the acceleration of the prismatic actuator is obtained by forming the Klein form, or reciprocal product, with the accelerator and the coordinates of the line of the connector chain. Since the Klein form is invariant, the resulting expression can be applied directly to the six HPS connector chains of an in-parallel manipulator. As a required intermediate step, this contribution also derives the corresponding solutions for the forward and inverse velocity analyses. The authors believe that this simple method has applications in the dynamics and control of these in-parallel manipulators where the computing time must be minimized to improve the behavior of parallel manipulators. [S1050-0472(00)01303-9]

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