Kinematic modeling of Exechon parallel kinematic machine

Bi, Zhuming; Jin, Yan

doi:10.1016/j.rcim.2010.07.006

Cited by 170 publications

(84 citation statements)

References 9 publications

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“…In unconventional parallel robot structures, which have a complex configuration of actuators and joints, such differences are due to difficulties in modelling the non-linear mapping between actuator and machining coordinate spaces [5]. This is problematic because parallel kinematic hexapod robots are desirable for machining due to their stiffness benefits [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Achievable tolerances in robotic feature machining operations using a low-cost hexapod

Barnfather

Goodfellow

Abram

2017

Int J Adv Manuf Technol

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Portable robotic machine tools potentially allow feature machining processes to be brought to large parts in various industries, creating an opportunity for capital expenditure and operating cost reduction. However, robots lack the machining capability of conventional equipment, which ultimately results in dimensional errors in parts. This work showcases a low-cost hexapod-based robotic machine tool and presents experimental research conducted to investigate how the widely researched robotic machining challenges, e.g. structural dynamics and kinematics, translate to achievable tolerance ranges in real-world production to highlight currently feasible applications and provide a context for considering technology improvements. Machining trials assess the total dimensional errors in the final part over multiple geometries. A key finding is error variation which is in the sub-millimetre range, although, in some cases, upper tolerance limits < 100 μm are achieved. Practical challenges are also noted. Most significantly, it is demonstrated that dimensional machining error is mainly systematic in nature and therefore that the total error can be dramatically reduced with in situ measurement and compensation. Potential is therefore found to achieve a flexible, highperformance robotic machining capability despite complex and diverse underlying scientific challenges. Overall, the work presented highlights achievable tolerances in lowcost robotic machining and opportunities for improvement, also providing a practical benchmark useful for process selection.

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Section: Introductionmentioning

confidence: 99%

Achievable tolerances in robotic feature machining operations using a low-cost hexapod

Barnfather

Goodfellow

Abram

2017

Int J Adv Manuf Technol

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“…The hexapod robot format is of interest for machining applications because of stiffness benefits and noncumulative error stack up in independent links and joints, which provides improved chatter resistance and accuracy compared to serial-arm alternatives [1][2][3][4][5][6]. A limitation to robotic machining using hexapod industrial robots is that they are less able to achieve the higher machining tolerances of conventional machine tools due to relative differences in structural rigidity and tool deflection and challenges associated with control algorithms, encoder capability and component misalignments [7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Positional capability of a hexapod robot for machining applications

Barnfather

Goodfellow

Abram

2016

Int J Adv Manuf Technol

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In large volume manufacturing, moving heavy components around manufacturing facilities to machine features on them can represent a significant proportion of the parts final cost because the tools used for this require a high initial investment and operating costs. This motivates interest in robotic machining so that the "process-to-part" concept can be employed. However, typical industrial robots lack the positional capability of conventional equipment, which ultimately results in dimensional errors in the features machined. This research investigates accumulation of error originating from non-cutting stages of robotic machining programs, using a hexapod robot. This is done using a procedure adapted from ISO 9283-Manipulating Industrial Robots-Performance Criteria and Related Test Methods to determine positional accuracy and repeatability, i.e. systematic and random errors. This concludes that, although the robot encounters high levels of error prior to cutting, a portion of these may be offset with in-situ condition monitoring to facilitate higher tolerance machining. Potential is therefore found for using robot machining for manufacturing cost reduction in the large-scale manufacturing industries.

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“…In fact, most of the parallel manipulators used successfully in industrial applications belong to the low-mobility category. Examples of such cases are the Delta [5], Tricept [6], Exechon [7], and Sprint Z3 heads [8], among others. Especially in thin-wall machining applications for structural aluminium aerospace components, the emergence of the Sprint Z3 tool head (Figure 1) produced by the DS Technologie Company in Germany [8] has attracted widespread attention from the machine tool user community.…”

Section: Introductionmentioning

confidence: 99%

A Comparison Study on Motion/Force Transmissibility of Two Typical 3-DOF Parallel Manipulators: The Sprint Z3 and A3 Tool Heads

Chen

Liu

Xie

et al. 2014

International Journal of Advanced Robotic Systems

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This paper presents a comparison study of two important three-degree-of-freedom (DOF) parallel manipulators, the Sprint Z3 head and the A3 head, both commonly used in industry. As an initial step, the inverse kinematics are derived and an analysis of two classes of limbs is carried out via screw theory. For comparison, three transmission indices are then defined to describe their motion/force transmission performance. Based on the same main parameters, the compared results reveal some distinct characteristics in addition to the similarities between the two parallel manipulators. To a certain extent, the A3 head outperforms the common Sprint Z3 head, providing a new and satisfactory option for a machine tool head in industry.

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Kinematic modeling of Exechon parallel kinematic machine

Cited by 170 publications

References 9 publications

Achievable tolerances in robotic feature machining operations using a low-cost hexapod

Achievable tolerances in robotic feature machining operations using a low-cost hexapod

Positional capability of a hexapod robot for machining applications

A Comparison Study on Motion/Force Transmissibility of Two Typical 3-DOF Parallel Manipulators: The Sprint Z3 and A3 Tool Heads

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