Stewart platform thesis

This study proposes a novel Gough-Stewart platform-based manipulator with ultra-high stiffness and accuracy for use in biomechanical testing and investigates its mechanism and control. Sheep functional spinal units are used to experimentally validate the method on the custom-built Gough-Stewart platform-based manipulator.

Wed 24 May Stiffness and Control of the Non-collocated Actuator-Sensor Mechanism A novel Gough-Stewart platform-based mechanism is proposed with a fully decoupled actuator-sensor arrangement for passively compensating the structural compliance of the manipulator.

School of Mechanical Engineering Abstract: Consequently the in-vivo measured wrist kinematics is transformed to the kinematics of the robotic testing system, which is used to reproduce the hammering motion. Six degree of freedom 6-DOF robotic-based systems, in particular Gough-Stewart platform-based systems, have been increasingly used in applications of biomechanical testing where 6-DOF mobility, large load capacity, and high stiffness and positioning accuracy are required from Stewart platform thesis testing machine.

It is also highlighted that there are no need to model any inverse kinematics of the Gough-Stewart platform.

FAQ: M.S. Thesis: Stewart Platform with Fixed Actuators

Reproducing the In-vivo Measured Kinematics on Human Cadaveric Joints This thesis develops a method to scientifically reproduce the general in-vivo kinematics measured from a living human on human cadaver joints using the custom-built Gough-Stewart platform-based manipulator.

The proposed method uses a 3-D motion capture system to collect the Stewart platform thesis wrist kinematics from 12 patients undertaking hammering motion. Experimental results illustrate the efficiency of the proposed method, which can be further improved when overcoming certain limitations of the system e.

Experimental results also show that the assumption of fixed wrist joint centre of rotation is valid for motion reproduction.

Four main features of the proposed manipulator are individually studied in this thesis: Numerical results demonstrate that the proposed mechanism improves the stiffness of the robotic testing system in excess of an order of magnitude on the translational axes and two orders of magnitude for rotational axes compared to a traditional actuator-sensor collocated design.

In parallel, CT scans and static motion capture are undertaken on 8 cadaveric human wrist specimens in an effort to define the locations of the coordinate systems. Simulation results also show that the proposed method can effectively achieve backlash-free positioning of the manipulator under large 6-DOF external loads.

The outcome of this work demonstrates that a Gough-Stewart platform is applicable for real-time tracking of chassis motions.

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Those automobiles are either actual vehicles that are driven on outdoor roads, or automobiles that are run in a simulation program. A human wrist is used as a typical example to elaborate the theory of the method and to assess the fidelity of the method. Instead, it is sufficient to combine forward kinematics of the Gough-Stewart platform with a simple but distributed control Stewart platform thesis design to achieve adequate tracking performance.

Adaptive Velocity-based Load Control of Human Joint for Unconstrained Testing A novel adaptive velocity-based load control method is proposed in this thesis to more effectively achieve pure force or moments on human joints under unconstrained testing compared to existing methods.

Active Preload Control Using Actuation Redundancy for Backlash Elimination This thesis investigates combining the benefits of both active and passive preload control methods, using actuation redundancy to prevent backlash on a general Gough- Stewart platform.

The stiffness of the robot load frame and the sensing frame are respectively quantified using the robot kinematics error model combined with finite element analysis FEA on the top and bottom assemblies. The Gough-Stewart platform is thus firstly fed motional reference data from an automobile chassis, and then the platform mimics those motions.

Both the mechanical configuration and the dynamics model of the redundant manipulator are investigated for the ease of control. A novel online optimization algorithm combined with a feedback force control scheme is formulated to achieve a real-time method which is robust to both model inaccuracy and load disturbance.

Experimental results further prove that the proposed method can eliminate backlash instabilities from control and consequently higher bandwidth control can be achieved by the robot with improved accuracy.

More specifically, there are two automobile headlights attached atop of the Gough-Stewart platform, and the idea is for those headlights to imitate the behaviour of the headlights utilised in real, operated automobiles.

Hence, the Gough-Stewart platform is able to perform motion in six degrees of freedom, but in this application only three heave, pitch, roll are utilised. In addition, a control system that allows the Gough-Stewart platform to perform real-time tracking of chassis motions is implemented.

Simulation results demonstrate an effective preload efficacy by the redundant arrangement within the workspace of the robot. These regulators are governed by a centralised logic unit that receives the reference data which contains the chassis motions.

Not only restricted to biomechanical testing, the proposed manipulator concept can also be applied to other robotic-based applications, particularly those requiring ultra-high accuracy positioning under large external loads e. This thesis investigates the development and application of a robotic system for in-vitro biomechanical testing to study the mechanisms leading to human joint injury and degeneration in an ethical and safe manner.

Experimental results show that the accuracy of the reproduced motion on the cadaveric samples is of similar magnitude to the measurement error of the motion capture system. In order to achieve a sufficient imitation of chassis motions in real-time, a mathematical model of the Gough-Stewart platform is developed.

This sensor data is processed through the mathematical model to obtain actuator length set-points, which are transmitted in a steady real-time stream from the logic unit to the PID regulators.

Control disturbances arising from actuator-sensor non-collocation is addressed using decoupled control.A Study of a Gough-Stewart Platform-based Manipulator for Applications in Biomechanical Testing Boyin Ding This thesis investigates combining the benefits of both active and passive preload Active Preload Control of a Redundantly Actuated Stewart Platform for.

Active Preload Control Using Actuation Redundancy for Backlash Elimination This thesis investigates combining the benefits of both active and passive preload control methods, using actuation redundancy to prevent backlash on a general Gough- Stewart platform.

Dynamic Modeling and Simulation of Stewart Platform

Figure 7. Stewart Platform with fixed actuators relative to the heart and platform trajectory marked with a dotted line, Figure 8. Approximate dimensions of the Stewart Platform can be calculated choosing margin angles (and. Platform is observed in neutral position and at the end-point of the trajectory.

Design and testing of a Stewart Platform Augmented Manipulator for space applications

Zafer Bingul and Oguzhan Karahan (March 30th ). Dynamic Modeling and Simulation of Stewart Platform, Serial and Parallel Robot Manipulators Serdar Kucuk, IntechOpen, DOI: / Available from: Zafer Bingul and Oguzhan Karahan (March 30th ).

Singularity Analysis and Representation of the General Gough-Stewart Platform

Dynamic Modeling and Simulation of Stewart. A Study of a Gough-Stewart Platform-based Manipulator for Applications in Biomechanical Testing Boyin Ding School of Mechanical Engineering The University of Adelaide South Australia Australia A thesis submitted in fulfillment of the requirements for the degree of Ph.D.

in Mechanical Engineering on 15 October Qualified on 5 February Links: [ home | thesis] FAQ: M.S. Thesis: Stewart Platform with Fixed Actuators Q1. Excerpt from thesis: From an e-mail: This is where I have the problem I would want to know what dg(si)/ds is bcos this is what I have assumed from the equation 20 that dR/dqj is a 4*4 matrix like dR/dx then dR/dy and so on till gama.

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Stewart platform thesis
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