T-Flex: A fully flexure-based large range of motion precision hexapod

Naves, Mark; Nijenhuis, Marijn; Seinhorst, Bram; Hakvoort, Wouter; Brouwer, Dannis Michel

doi:10.1016/j.precisioneng.2021.08.015

Cited by 8 publications

(7 citation statements)

References 14 publications

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“…Thereafter, the normalised parameter drift R 1 is taken to be a diagonal matrix with 10 −5 at the entries corresponding the inertial properties of the endeffector and 10 −7 at the other entries. The measurement noise covariance is set at R 2 = 10 −4 I (Nm) 2 , with I being the identity matrix. This covariance corresponds to the observed flat and equal torque measurement noise for each of the actuators.…”

Section: E Newton Raphson (N F and N E )mentioning

confidence: 99%

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Efficient Formulation of Hexapod Kinematics Enabling Real Time Adaptive Feedforward Control

Seinhorst

Hakvoort

2021

2021 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM)

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The tracking performance of manipulators can be improved considerably by adaptive feedforward control (AFFC). However, complex kinematics hinder the application to parallel kinematic manipulators (PKMs). This paper proposes a compact and efficient formulation of the full PKM kinematics enabling real-time application of AFFC to complex PKMs. The efficient kinematic formulation is the basis for the inverse dynamics used to compute the feedforward signal. A Kalman filter is used for online estimation of the parameters in the equations of motion. A parallel multi-rate implementation is used, which, together with the efficient kinematic formulation, allows for a feedforward sampling time as low as 0.5 ms. The parameters are updated every 30 ms, which suffices to track the slow parameter variations. The application to a highly repeatable flexure-based manipulator is considered. Experimental results for the manipulator show that the tracking error can be reduced by 97.5% compared to using feedback control only.

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Section: E Newton Raphson (N F and N E )mentioning

confidence: 99%

“…The low moving mass typically allows for high accelerations and a relatively high payload mass. Recently the T-Flex, a fully flexure-based 6 degree of freedom (DoF) PKM, was developed [2]. The use of flexures instead of conventional bearings results in a highly repeatable system.…”

Section: Introductionmentioning

confidence: 99%

Efficient Formulation of Hexapod Kinematics Enabling Real Time Adaptive Feedforward Control

Seinhorst

Hakvoort

2021

2021 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM)

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“…An example of such an application is the T-flex [130,135], a high precision manipulator for a large range of motion, see Figure 1.2(b). This six-degrees-of-freedom robot contains six revolute joints and twelve spherical joints.…”

Section: Background -Flexure Mechanismsmentioning

confidence: 99%

“…Flexure joints are often utilized in mechanisms for their deterministic behaviour, making them excellent for precision applications [4,77,135,147,179,200]. However, their range of motion is limited due to stress constraints and due to the deterioration of the support stiffness with deflection.…”

Section: Introductionmentioning

confidence: 99%

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Beam-based analysis of flexure mechanisms: increasing computational efficiency, accuracy and design freedom

Dwarshuis

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The use of beam elements with constant cross-section limits the design freedom. This thesis presents a formulation for beam elements with a varying cross-section, to allow for the analysis of non-prismatic flexures. Design optimizations of several flexure joints shows that this extra design freedom can result in significantly better flexure joints.Flexure joints contain parts which connect the flexures to each other. Although these socalled frame parts are intended to be very stiff, their compliance can significantly decrease the overall support stiffness of the flexure joints, reducing the performance. An accurate evaluation of the performance requires the stiffness of the frame parts to be modelled. However, frame parts typically have complex shapes, such that they can barely be modelled using beam elements. This thesis formulates a superelement by which complex shaped parts can be modelled efficiently. Examples show that flexure joints can be modelled efficiently and accurately by using the superelement to model frame parts and using beam elements to model the flexures.Very complex flexure-based mechanisms can be analysed more efficiently and more accurately by using the methods and elements that are introduced in this thesis. This may help the development of new flexure mechanisms, increasing the potential for using flexure mechanisms in practice.

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Computational optimization of a steel A-36 monolithic mechanism by bonobo algorithm and intelligent model for precision machining application

Nguyen

Dang

Huang

et al. 2022

Int J Interact Des Manuf

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T-Flex: A fully flexure-based large range of motion precision hexapod

Cited by 8 publications

References 14 publications

Efficient Formulation of Hexapod Kinematics Enabling Real Time Adaptive Feedforward Control

Efficient Formulation of Hexapod Kinematics Enabling Real Time Adaptive Feedforward Control

Beam-based analysis of flexure mechanisms: increasing computational efficiency, accuracy and design freedom

Computational optimization of a steel A-36 monolithic mechanism by bonobo algorithm and intelligent model for precision machining application

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