Operational Envelope of a Spatial Stewart Platform

1997 ◽  
Vol 119 (2) ◽  
pp. 330-332 ◽  
Author(s):  
F. A. Adkins ◽  
E. J. Haug
Keyword(s):  
Numerical Methods ◽  
Driving Simulator ◽  
Stewart Platform ◽  
Degree Of Freedom ◽  
Graphical Form ◽  
Prior Work ◽  
Unilateral Constraints ◽  
Planar Mechanisms ◽  
Operational Envelope ◽  
Six Degree Of Freedom

This technical brief presents the operational envelope for the spatial Stewart platform and dome of a six degree of freedom driving simulator, extending prior work that has been limited to planar mechanisms and manipulators. The set of all points in space that can be occupied by any point in the dome of the simulator is defined as its operational envelope. The geometry of the driving simulator’s dome and unilateral constraints on actuator lengths are incorporated and details of the defining equations for the operational envelope are given. Numerical methods are used to calculate the boundary of the operational envelope and results are presented in graphical form.

Six Degree of Freedom Active Isolation in Flexible Supporting Structures: Numerical Simulation and Experiment

2003 ◽  
Author(s):  
Yuan Cheng ◽  
Qian Zhou ◽  
Ge-Xue Ren ◽  
Hui Zhang
Keyword(s):  
Stewart Platform ◽  
Degree Of Freedom ◽  
Active Isolation ◽  
Dynamics And Control ◽  
Six Degree Of Freedom ◽  
Multi Body ◽  
And Control ◽  
Flexible Cables ◽  
Base Platform ◽  
Supporting Structures

This paper studies the six degree-of-freedom active isolation of flexible supporting structures using Gough-Stewart platform. The problem arises from a large radio telescope in which the astronomical equipment is mounted on a platform to be stabilized, while the base platform of the mechanism itself is carried by a cable car moving along flexible cables. In this paper, the stabilization problem is equivalent to a dynamics and control problem of multi-body system. A control law of the prediction of the base platform and PD feedback is proposed for the six actuators of the Gough-Stewart platform. Based on numerical results, a model experimental setup has been built up. The control effects are measured with LTD 500 Laser Tracker.

Dynamic Modeling of a Six Degree-of-Freedom Flight Simulator Motion Base

2015 ◽  
Vol 10 (5) ◽  
Author(s):  
Mauricio Becerra-Vargas ◽  
Eduardo Morgado Belo
Keyword(s):  
Closed Form ◽  
Dynamic Model ◽  
Kinematic Model ◽  
Closed Form Solution ◽  
Stewart Platform ◽  
Degree Of Freedom ◽  
Dynamic Equations ◽  
Flight Simulator ◽  
Simulator Motion ◽  
Six Degree Of Freedom

This paper presents a closed-form solution for the direct dynamic model of a flight simulator motion base. The motion base consists of a six degree-of-freedom (6DOF) Stewart platform robotic manipulator driven by electromechanical actuators. The dynamic model is derived using the Newton–Euler method. Our derivation is closed to that of Dasgupta and Mruthyunjaya (1998, “Closed Form Dynamic Equations of the General Stewart Platform Through the Newton–Euler Approach,” Mech. Mach. Theory, 33(7), pp. 993–1012), however, we give some insights into the structure and properties of those equations, i.e., a kinematic model of the universal joint, inclusion of electromechanical actuator dynamics and the full dynamic equations in matrix form in terms of Euler angles and platform position vector. These expressions are interesting for control, simulation, and design of flight simulators motion bases. Development of a inverse dynamic control law by using coefficients matrices of dynamic equation and real aircraft trajectories are implemented and simulation results are also presented.

Workspace Analysis of Closed Loop Mechanisms With Unilateral Constraints

1989 ◽  
Author(s):  
D.-Y. Jo ◽  
E. J. Haug
Keyword(s):  
Numerical Methods ◽  
Closed Loop ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Inequality Constraints ◽  
Stewart Platform ◽  
Unilateral Constraints ◽  
Higher Dimensional ◽  
Workspace Analysis ◽  
Slack Variable

Abstract Kinematics of mechanisms that contain elements with unilateral constraints such as stops are characterized by systems of equalities and inequalities. A slack variable formulation is introduced to convert inequality constraints to equalities, in a higher dimensional space of variables. The slack variable formulation permits use of manifold based theoretical and numerical methods for analysis of the boundaries of workspaces. The workspace of a simplified Stewart platform is analyzed, including rotatability of the top platform. Sets of reachable points of the top platform of a three dimensional Stewart platform, with fixed platform orientation, are analyzed.

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