Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 1997
Abstract A simulation model of a rotary pneumatic servo system has been developed and verified ag... more Abstract A simulation model of a rotary pneumatic servo system has been developed and verified against an experimental system. The double-acting rotary actuator is a novel device utilizing flexible inflatable bladders. The device differs from conventional pneumatic cylinders in that it exhibits low levels of friction, as it has no sliding seals, but it does suffer from hysteresis caused by bladder distortion. The objective of this study was to develop a tool with which to investigate the effect of various forms of hysteresis and other parameters on system performance. The dynamic model utilizes a linearized analysis of pneumatic components based on earlier studies. The principal advance described in this paper relates to the inclusion of non-linear elements. These are hysteresis caused by friction or the distortion of flexible components, and a digital controller implementation. The simulation successfully predicted all major modes of behaviour. Simplified models of rubber and coulomb friction-induced hysteresis modified simulation performance in line with experimental results. An investigation in simulation showed that coulomb friction-induced hysteresis had a greater damping effect than that caused by distorting the bladders. This result applies only to position control, as hysteresis has been shown not to provide damping in trajectory control applications.
Because it is sometimes possible to convert one into the other, money and wealth are often confus... more Because it is sometimes possible to convert one into the other, money and wealth are often confused. But they are distinct: money is pieces of paper or numbers in a computer; wealth is corn to make bread, or a motor car. Both money and wealth grow as time advances: growth in money is inflation, growth in wealth is longevity and prosperity. Is it possible to grow wealth independently of money? This talk will be from Adrian Bowyer - creator of RepRap, the open-source replicating 3D printer - and from David Cuartielles - creator of Arduino, the open-source microcontroller. Both projects have founded significant and growing industries - and hence significant and growing wealth - by giving away all the data required to build RepRaps and Arduinos completely free. They have also short-circuited most conventional industrial infrastructure by placing the ability to create wealth directly in the hands of private individuals. The presenters contend that this is the way of the future: companies...
this paper we present a new method of feature recognition that works entirelyon set-theoretic geo... more this paper we present a new method of feature recognition that works entirelyon set-theoretic geometric models, and which allows features to be foundwhen there are small geometrical deviations
This paper presents a multidimensional CSG geometric modeller. It then shows how this modeller ca... more This paper presents a multidimensional CSG geometric modeller. It then shows how this modeller can be used to produce a compact representation of the complete configuration-space map of a mechanism composed of polyhedral parts. The map is derived directly from the three-dimensional geometric model that describes the mechanism, and allows more degrees of freedom than any other current system. Methods of exploring the map to give the kinematics of the mechanism will also be described and examples will be given. We will then go on to show how geometric constraints can be reformulated as a multidimensional CSG expression describing the constraints problem in a space similar to the configuration space above. Geometric constraints representing mechanisms will be described and the resulting mechanisms shown. Finally we will show how the two techniques, which are both coded using the same multidimensional modeller, can be combined. This allows parts of a machine that are known (such as slides and hinges) to be de...
When components have been made they need to be inspected. In this paper some newly devised automa... more When components have been made they need to be inspected. In this paper some newly devised automatic methods are described that compare a set of measurements of an engineering component taken by a coordinate measuring machine with a master solid model of the measured component obtained from a CAD system. Once matched, the two may then be compared to find any differences resulting from manufacturing errors and those manufacturing errors can automatically be reported.
Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of ... more Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of a new research project, whose necessity arises both from the computational imperative of applying algebra to CAD and the difficulties of applying existing systems to ...
Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 1997
Abstract A simulation model of a rotary pneumatic servo system has been developed and verified ag... more Abstract A simulation model of a rotary pneumatic servo system has been developed and verified against an experimental system. The double-acting rotary actuator is a novel device utilizing flexible inflatable bladders. The device differs from conventional pneumatic cylinders in that it exhibits low levels of friction, as it has no sliding seals, but it does suffer from hysteresis caused by bladder distortion. The objective of this study was to develop a tool with which to investigate the effect of various forms of hysteresis and other parameters on system performance. The dynamic model utilizes a linearized analysis of pneumatic components based on earlier studies. The principal advance described in this paper relates to the inclusion of non-linear elements. These are hysteresis caused by friction or the distortion of flexible components, and a digital controller implementation. The simulation successfully predicted all major modes of behaviour. Simplified models of rubber and coulomb friction-induced hysteresis modified simulation performance in line with experimental results. An investigation in simulation showed that coulomb friction-induced hysteresis had a greater damping effect than that caused by distorting the bladders. This result applies only to position control, as hysteresis has been shown not to provide damping in trajectory control applications.
Because it is sometimes possible to convert one into the other, money and wealth are often confus... more Because it is sometimes possible to convert one into the other, money and wealth are often confused. But they are distinct: money is pieces of paper or numbers in a computer; wealth is corn to make bread, or a motor car. Both money and wealth grow as time advances: growth in money is inflation, growth in wealth is longevity and prosperity. Is it possible to grow wealth independently of money? This talk will be from Adrian Bowyer - creator of RepRap, the open-source replicating 3D printer - and from David Cuartielles - creator of Arduino, the open-source microcontroller. Both projects have founded significant and growing industries - and hence significant and growing wealth - by giving away all the data required to build RepRaps and Arduinos completely free. They have also short-circuited most conventional industrial infrastructure by placing the ability to create wealth directly in the hands of private individuals. The presenters contend that this is the way of the future: companies...
this paper we present a new method of feature recognition that works entirelyon set-theoretic geo... more this paper we present a new method of feature recognition that works entirelyon set-theoretic geometric models, and which allows features to be foundwhen there are small geometrical deviations
This paper presents a multidimensional CSG geometric modeller. It then shows how this modeller ca... more This paper presents a multidimensional CSG geometric modeller. It then shows how this modeller can be used to produce a compact representation of the complete configuration-space map of a mechanism composed of polyhedral parts. The map is derived directly from the three-dimensional geometric model that describes the mechanism, and allows more degrees of freedom than any other current system. Methods of exploring the map to give the kinematics of the mechanism will also be described and examples will be given. We will then go on to show how geometric constraints can be reformulated as a multidimensional CSG expression describing the constraints problem in a space similar to the configuration space above. Geometric constraints representing mechanisms will be described and the resulting mechanisms shown. Finally we will show how the two techniques, which are both coded using the same multidimensional modeller, can be combined. This allows parts of a machine that are known (such as slides and hinges) to be de...
When components have been made they need to be inspected. In this paper some newly devised automa... more When components have been made they need to be inspected. In this paper some newly devised automatic methods are described that compare a set of measurements of an engineering component taken by a coordinate measuring machine with a master solid model of the measured component obtained from a CAD system. Once matched, the two may then be compared to find any differences resulting from manufacturing errors and those manufacturing errors can automatically be reported.
Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of ... more Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of a new research project, whose necessity arises both from the computational imperative of applying algebra to CAD and the difficulties of applying existing systems to ...
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