31-10-2016, 09:34 AM
[attachment=74147]
Abstract
Space mouse opens a new age for man-machine communication.This device is based on the technology used to control the first robot in spaceand has been adapted for a wide range of tasks including mechanical design,real time video animation and visual simulation. It has become a standard input device for interactive motion control of three-dimensional graphic objects in up to six degrees of freedom. Space mouse works with standard serial mouse interface without an additional power supply. The ergonomic design allows the human hand to rest on it without fatigue. Thus flying an object in six degrees of freedom is done without any strain.
Every day of your computing life, you reach out for the mouse whenever you want to move the cursor or activate something. The mouse senses your motion and your clicks and sends them to the computer so it can respond appropriately. An ordinary mouse detects motion in the X and Y plane and acts as a two dimensional controller. It is not well suited for people to use in a 3D graphics environment.
Space Mouse is a professional 3D controller specifically designed for manipulating objects in a 3D environment. It permits the simultaneous control of all six degrees of freedom - translation rotation or a combination. The device serves as an intuitive man-machine interface.The predecessor of the spacemouse was the DLR controller ball. Spacemouse has its origins in the late seventies when the DLR (German Aerospace Research Establishment) started research in its robotics and system dynamics division on devices with six degrees of freedom (6 dof) for controlling robot grippers in Cartesian space. The basic principle behind its construction is mechatronics engineering and the multisensory concept. The spacemouse has different modes of operation in which it can also be used as a two-dimensional mouse.
INTRODUCTION
Every day of your computing life, you reach out for the mouse whenever you want to move the cursor or activate something. The mouse senses your motion and your clicks and sends them to the computer so it can respond appropriately. An ordinary mouse detects motion in the X and Y plane and acts as a two dimensional controller. It is not well suited for people to use in a 3D graphics environment. Space Mouse is a professional 3D controller specifically designed for manipulating objects in a 3D environment. It permits the simultaneous control of all six degrees of freedom - translation rotation or a combination. .
The device serves as an intuitive man-machine interface The predecessor of the spacemouse was the DLR controller ball. Spacemouse has its origins in the late seventies when the DLR (German Aerospace Research Establishment) started research in its robotics and system dynamics division on devices with six degrees of freedom (6 dof) for controlling robot grippers in Cartesian space. The basic principle behind its construction is mechatronics engineering and the multisensory concept. The space mouse has different modes of operation in which it can also be used as a two-dimensional mouse.
How does computer mouse work?
Mice first broke onto the public stage with the introduction of the AppleMacintosh in 1984, and since then they have helped to completelyredefine the way we use computers. Every day of your computing life,you reach out for your mouse whenever you want to move your cursor oractivate something. Your mouse senses your motion and your clicks andsends them to the computer so it can respond appropriately
2.1 Inside a Mouse
The main goal of any mouse is to translate the motion of your hand intosignals that the computer can use. Almost all mice today do thetranslation using five components:
MECHATRONICS
3.1 What is Mechatronics engineering?
Mechatronics is concerned with the design automation andoperational performance of electromechanical systems. Mechatronicsengineering is nothing new; it is simply the applications of latesttechniques in precision mechanical engineering, electronic and computer
control, computing systems and sensor and actuator technology to designimproved products and processes.The basic idea of Mechatronics engineering is to apply innovativecontrols to extract new level of performance from a mechanical device. Itmeans using modem cost effective technology to improve product andprocess performance, adaptability and flexibility.
Mechatronics covers a wide range of application areas includingconsumer product design, instrumentation, manufacturing methods,computer integration and process and device control. A typicalMechatronic system picks up signals processes them and generatesforces and motion as an output. In effect mechanical systems areextended and integrated with sensors (to know where things are),microprocessors (to work out what to do), and controllers (to perform therequired actions).
The word Mechatronics came up describing this fact of havingtechnical systems operating mechanically with respect to some kernelfunctions but with more or less electronics supporting the mechanicalparts decisively. Thus we can say that Mechatronics is a blending ofMechanical engineering,Electronics engineering and ComputingThese three disciplines are linked together with knowledge ofmanagement, manufacturing and marketing.
3.2 What do Mechatronics engineers do?
Mechatronics design covers a wide variety of applications fromthe physical integration and miniaturization of electronic controllers withmechanical systems to the control of hydraulically powered robots inmanufacturing and assembling factories.Computer disk drives are one example of the successfulapplication of Mechatronics engineering as they are required to providevery fast access precise positioning and robustness against variousdisturbances.
An intelligent window shade that opens and closes according tothe amount of sun exposure is another example of a Mechatronicsapplication.Mechatronics engineering may be involved in the design ofequipments and robots for under water or mining exploration as analternative to using human beings where this may be dangerous. In factMechatronics engineers can be found working in a range of industriesand project areas including
•Design of data collection, instrumentation and computerizedmachine tools.
•Intelligent product design for example smart cars and automationfor household transportation and industrial application.
•Design of self-diagnostic machines, which fix problems on theirown.
•Medical devices such as life supporting systems, scanners andDNA sequencing automation.
•Robotics and space exploration equipments.
•Smart domestic consumer goods
•Computer peripherals.
•Security systems.
3.3 Mechatronic goals
3.3.1 The multisensory concept
The aim was to design a new generation of multi sensorylightweight robots. The new sensor and actuator generation does not onlyshow up a high degree of electronic and processor integration but alsofully modular hardware and software structures. Analog conditioning,power supply and digital pre-processing are typical subsystems modulesof this kind. The 20khz lines connecting all sensor and actuator systemsin a galvanically decoupled way and high speed optical serial data bus(SERCOS) are the typical examples of multi sensory and multi actuatorconcept for the new generation robot envisioned.The main sensory developments finished with these criteria havebeen in the last years: optically measuring force-torque-sensor forassembly operations. In a more compact form these sensory systemswere integrated inside plastic hollow balls, thus generating 6-degree offreedom hand controllers (the DLR control balls). The SPACE-MOUSEis the most recent product based on these ideas.
•stiff strain-gauge based 6 component force-torque-sensor systems.
•miniaturized triangulation based laser range finders.
•integrated inductive joint-torque-sensor for light-weight-robot.
In order to demonstrate the multi sensory design concept, thesetypes of sensors have been integrated into the multi sensory DLRgripper,which contains 15 sensory components and to our knowledge itis the most complex robot gripper built so far (more than 1000miniaturized electronic and about 400 mechanical components). It hasbecome a central element of the ROTEX space robot experiment.
SPACEMOUSE
Spacemouse is developed by the DLR institute of robotics andmechatronics.DLR- Deutsches Zenturum far Luft-und Raumfahrt
4.1 Why 3D motion?
In every area of technology, one can find automata and systemscontrollable up to six degrees of freedom- three translational and threerotational. Industrial robots made up the most prominent categoryneeding six degrees of freedom by maneuvering six joints to reach anypoint in their working space with a desired orientation. Even broaderthere have been a dramatic explosion in the growth of 3D computergraphics.Already in the early eighties, the first wire frame models of
volume objects could move smoothly and interactively using so calledknob-boxes on the fastest graphics machines available.
A separate buttoncontrolled each of the six degrees of freedom. Next, graphics systems onthe market allowed manipulation of shaded volume models smoothly,i.e. rotate, zoom and shift them and thus look at them from any viewingangle and position. The scenes become more and more complex; e.g.with a "reality engine" the mirror effects on volume car bodies areupdated several times per second - a task that needed hours on main frame computers a couple of years ago.Parallel to the rapid graphics development, we observed a cleartrend in the field of mechanical design towards constructing andmodeling new parts in a 3D environment and transferring the resultingprograms to NC machines. The machines are able to work in 5 or 6degrees of freedom (dot). Thus, it is no surprise that in the last few years,there are increasing demands for comfortable 3D control andmanipulation devices for these kinds of systems. Despite breathtakingadvancements in digital technology it turned out that digital manmachine
interfaces like keyboards are not well suited for people to use asour sensomotory reactions and behaviors are and will remain analogousforever.
4.2 DLR control ball, Magellan's predecessor
At the end of the seventies, the DLR (German Aerospace ResearchEstablishment) institute for robotics and system dynamics startedresearch on devices for the 6-dof control of robot grippers .in Cartesianspace. After lengthy experiments it turned out around 1981 thatintegrating a six axis force torque sensor (3 force, 3 torque components)into a plastic hollow ball was the optimal solution. Such a ball registeredthe linear and rotational displacements as generated by the forces torques of a human hand, which were then computationally transformedinto translational / rotational motion speeds.
The first force torque sensor used was based upon strain gaugetechnology, integrated into a plastic hollow ball. DLR had the basicconcept centre of a hollow ball handle approximately coinciding with themeasuring centre of an integrated 6 dof force / torque sensor patented in
Europe and US.From 1982-1985, the first prototype applications showed that DLR'scontrol ball was not only excellently suited as a control device for robots,but also for the first 3D-graphics system that came onto the market atthat time. Wide commercial distribution was prevented by the high salesprice of about $8,000 per unit. It took until 1985 for the DLR's developergroup to succeed in designing a much cheaper optical measuring system.
4.2.1 Basic principle
The new system used 6 one-dimensional position detectors. Thissystem received a worldwide patent. The basic principle is as follows.The measuring system consists of an inner and an outer part. Themeasuring arrangement in the inner ring is composed of the LED, a slit
and perpendicular to the slit on the opposite side of the ring a linearposition sensitive detector (PSD). The slit / LED combination is mobileagainst the remaining system. Six such systems (rotated by 60 degreeseach) are mounted in a plane, whereby the slits alternatively are vertical
and parallel to the plane. The ring with PSD's is fixed inside the outerpart and connected via springs with the LED-slit-basis. The springs bringthe inner part back to a neutral position when no forces / torque areexerted: There is a particularly simple and unique. This measuringsystem is drift-free and not subject to aging effects.
The whole electronics including computational processing on aone-chip-processor was already integrable into the ball by means of twosmall double sided surface mount device (SMD) boards, themanufacturing costs were reduced to below $1,000, but the sales pricestill hovered in the area of $3,000.
The original hopes of the developers group that the licensecompanies might be able to redevelop devices towards much lowermanufacturing costs did not materialize. On the other hand, with passingof time, other technologically comparable ball systems appeared on the
market especially in USA. They differed only in the type of measuringsystem. Around 1990, terms like cyberspace and virtual reality becamepopular. However, the effort required to steer oneself around in a virtualworld using helmet and glove tires one out quickly. Movements were
measured by electromagnetic or ultrasonic means, with the human headhaving problems in controlling translational speeds. In addition, movingthe hand around in free space leads to fairly fast fatigue. Thus a redesignof the ball idea seemed urgent.
4.3 Magellan (the European Spacemouse):
The result of a long development chain
With the developments explained in the previous sections, DLR'sdevelopment group started a transfer company, SPACE CONTROL andaddressed a clear goal: To redesign the control ball idea with itsunsurpassed opto electronic measuring system and optimize it thus thatto reduce manufacturing costs to a fraction of its previous amount andthus allow it to approach the pricing level of high quality PC mouse atleast long-term.
The new manipulation device would also be able to function as aconventional mouse and appear like one, yet maintain its versatility in areal workstation design environment. The result of an intense one-year'swork was the European SpaceMouse, in the USA it is especially in the
European market place. But end of 93, DLR and SPACE CONTROLjointly approached LOGITECH because of their wide expertise withpointing devices for computers to market and sell Magellan in USA andAsia.
The wear resistant and drift free opto electronic, 6 componentmeasuring system was ptimized to place all the electronics, includingthe analogous signal processing, AT conversion, computationalevaluation and power supply on only one side of a tiny SMD- boardinside Magellan's handling cap. It only needs a few milliamperes ofcurrent supplied through the serial port of any PC or standard mouseinterface. It does not need a dedicated power supply. The electroniccircuitry using a lot of time multiplex technology was simplified by afactor of five, compared to the former control balls mentioned before.The unbelievably tedious mechanical optimization, where the simpleadjustment of the PSD's with respect to the slits played a central role inits construction, finally led to 3 simple injection moulding parts, namelythe basic housing, a cap handle with the measuring system inside and thesmall nine button keyboard system.
The housing, a punched steel plateprovides Magellan with the necessary weight for stability; any kind ofmetal cutting was avoided. The small board inside the cap (including abeeper) takes diverse mechanical functions as well. For example, itcontains the automatically mountable springs as well as overloadprotection. The springs were optimized in the measuring system so thatthey no longer show hysteresis; nevertheless different stiffness of the capare realizable by selection of appropriate springs. Ergonomically,Magellan was constructed as flat as can be so that the human hand mayrest on it without fatigue.
Slight pressures of the fingers on the cap of Magellan is sufficientfor generating deflections in X, Y, and Z planes, thus shifting a cursor orflying a 3D graphics object translationally through space. Slight twists ofthe cap cause rotational motions of a 3D graphics object around thecorresponding axes. Pulling the cap in the Z direction corresponds tozooming function. Moving the cap in X or Y direction drags thehorizontally and vertically respectively on the screen. Twisting the capover one of the main axes or any combination of them rotates the object
over the corresponding axis on the screen.
The user can handle theobject on the screen a he were holding it in his own left hand and helpingthe right hand to undertake the constructive actions on specific pointslines or surfaces or simply by unconsciously bringing to the front ofappropriate perspective view of any necessary detail of the object. Withthe integration of nine additional key buttons any macro functions can bemapped onto one of the keys thus allowing the user most frequentfunction to be called by a slight finger touch from the left hand.
Thedevice has special features like dominant mode.It uses those degrees of freedom in which the greatest magnitudeis generated. So defined movements can be created. Connection to thecomputer is through a 3m cable (DB9 female) and platform adapter ifnecessary. Use of handshake signals (RTSSCTS) are recommended forthe safe operation of the spacemouse. Without these handshake signalsloss of data may occur. Additional signal lines are provided to power theMagellan (DTS&RTS). Thus, no additional power supply is needed.Flying an object in 6 dof is done intuitively without any strain. In asimilar way, flying oneself through a virtual world is just fun. Touchingthe keys results in either the usual menu selection, mode selection or thepickup of 3D objects.
MAGELLAN: FEATURES AND BENEFITS
5.1 Features
•Ease of use of manipulating objects in 3D applications.
•Calibration free sensor technology for high precision and uniquereliability.
•Nine programmable buttons to customize users preference formotion control
•Fingertip operation for maximum precision and performance.
•Settings to adjust sensitivity and motion control to the userspreference.
•Small form factor frees up the desk space.
•Double productivity of object manipulation in 3D applications.
•Natural hand position (resting on table) eliminates fatigue.
5.2 Benefits
As the user positions the 3D objects with the Magellan device thenecessity of going back and forth to the menu is eliminated. Drawingtimes is reduced by 20%-30% increasing overall productivity. With theMagellan device improved design comprehension is possible and earlier
detection of design errors contributing faster time to market and costsavings in the design process. Any computer whose graphics powerallows to update at least 5 frames per second of the designed scenery,and which has a standard RS232 interface, can make use of the fullpotential of Magellan spacemouse. In 3D applications Magellan is usedin conjunction with a 2D mouse. The user positions an object withspacemouse while working on the object using a mouse. We canconsider it as a workman holding an object in his left hand and workingon it with a tool in his right hand. Now Magellan spacemouse isbecoming something for standard input device for interactive motioncontrol of 3D graphics objects in its working environment and for manyother applications.
FUTURE SCOPE
Magellan's predecessor, DLR's control ball, was a key element ofthe first real robot inspace, ROTEX- (3), which was launched in April 93with space shuttle COLUMBIA inside a rack of the spacelab-D2. Therobot was directly teleoperated by the astronauts using the control ball,the same way remotely controlled from ground (on-line and off line)implying "predictive" stereographics. As an example, the groundoperator with one of the two balls or Magellans steered the robot'sgripper in the graphics presimulation, while with the second device hewas able to move the whole scenery around smoothly in 6 dot Predictivegraphics simulation together with the above mentioned man machineinteraction allowed for the compensation of overall signal delays up toseven seconds, the most spectacular accomplishment being the grasping
of a floating object in space from the ground. Since then, ROTEX hasoften been declared as the first real "virtual reality" application.
6.1.1 VISUAL SPACEMOUSE
A most intuitive controlling device would be a system that can beinstructed by watching and imitating the human user, using the hand asthe major controlling element. This would be a very comfortableinterface that allows the user to move a robot system in the most naturalway. This is called the visual space mouse. The system of the visualspace mouse can be divided into two main parts: image processing androbot control. The role of image processing is to perform operations on avideo signal, received by a video camera, to extract desired information
out of the video signal. The role of robot control is to transformelectronic commands into movements of the manipulator.
CHAPTER 7
CONCLUSION
The graphics simulation and manipulation of 3D volume objectsand virtual worlds and their combination e.g. with real information ascontained in TV images (multi-media) is not only meaningful for spacetechnology, but will strongly change the whole world of manufacturing
and construction technology, including other areas like urbandevelopment, chemistry, biology, and entertainment. For all theseapplications we believe there is no other man- machine interface
technology comparable to Magellan in its simplicity and yet highprecision. It is used for 3D manipulations in 6 dof, but at the same timemay function as a conventional 2D mouse.
Abstract
Space mouse opens a new age for man-machine communication.This device is based on the technology used to control the first robot in spaceand has been adapted for a wide range of tasks including mechanical design,real time video animation and visual simulation. It has become a standard input device for interactive motion control of three-dimensional graphic objects in up to six degrees of freedom. Space mouse works with standard serial mouse interface without an additional power supply. The ergonomic design allows the human hand to rest on it without fatigue. Thus flying an object in six degrees of freedom is done without any strain.
Every day of your computing life, you reach out for the mouse whenever you want to move the cursor or activate something. The mouse senses your motion and your clicks and sends them to the computer so it can respond appropriately. An ordinary mouse detects motion in the X and Y plane and acts as a two dimensional controller. It is not well suited for people to use in a 3D graphics environment.
Space Mouse is a professional 3D controller specifically designed for manipulating objects in a 3D environment. It permits the simultaneous control of all six degrees of freedom - translation rotation or a combination. The device serves as an intuitive man-machine interface.The predecessor of the spacemouse was the DLR controller ball. Spacemouse has its origins in the late seventies when the DLR (German Aerospace Research Establishment) started research in its robotics and system dynamics division on devices with six degrees of freedom (6 dof) for controlling robot grippers in Cartesian space. The basic principle behind its construction is mechatronics engineering and the multisensory concept. The spacemouse has different modes of operation in which it can also be used as a two-dimensional mouse.
INTRODUCTION
Every day of your computing life, you reach out for the mouse whenever you want to move the cursor or activate something. The mouse senses your motion and your clicks and sends them to the computer so it can respond appropriately. An ordinary mouse detects motion in the X and Y plane and acts as a two dimensional controller. It is not well suited for people to use in a 3D graphics environment. Space Mouse is a professional 3D controller specifically designed for manipulating objects in a 3D environment. It permits the simultaneous control of all six degrees of freedom - translation rotation or a combination. .
The device serves as an intuitive man-machine interface The predecessor of the spacemouse was the DLR controller ball. Spacemouse has its origins in the late seventies when the DLR (German Aerospace Research Establishment) started research in its robotics and system dynamics division on devices with six degrees of freedom (6 dof) for controlling robot grippers in Cartesian space. The basic principle behind its construction is mechatronics engineering and the multisensory concept. The space mouse has different modes of operation in which it can also be used as a two-dimensional mouse.
How does computer mouse work?
Mice first broke onto the public stage with the introduction of the AppleMacintosh in 1984, and since then they have helped to completelyredefine the way we use computers. Every day of your computing life,you reach out for your mouse whenever you want to move your cursor oractivate something. Your mouse senses your motion and your clicks andsends them to the computer so it can respond appropriately
2.1 Inside a Mouse
The main goal of any mouse is to translate the motion of your hand intosignals that the computer can use. Almost all mice today do thetranslation using five components:
MECHATRONICS
3.1 What is Mechatronics engineering?
Mechatronics is concerned with the design automation andoperational performance of electromechanical systems. Mechatronicsengineering is nothing new; it is simply the applications of latesttechniques in precision mechanical engineering, electronic and computer
control, computing systems and sensor and actuator technology to designimproved products and processes.The basic idea of Mechatronics engineering is to apply innovativecontrols to extract new level of performance from a mechanical device. Itmeans using modem cost effective technology to improve product andprocess performance, adaptability and flexibility.
Mechatronics covers a wide range of application areas includingconsumer product design, instrumentation, manufacturing methods,computer integration and process and device control. A typicalMechatronic system picks up signals processes them and generatesforces and motion as an output. In effect mechanical systems areextended and integrated with sensors (to know where things are),microprocessors (to work out what to do), and controllers (to perform therequired actions).
The word Mechatronics came up describing this fact of havingtechnical systems operating mechanically with respect to some kernelfunctions but with more or less electronics supporting the mechanicalparts decisively. Thus we can say that Mechatronics is a blending ofMechanical engineering,Electronics engineering and ComputingThese three disciplines are linked together with knowledge ofmanagement, manufacturing and marketing.
3.2 What do Mechatronics engineers do?
Mechatronics design covers a wide variety of applications fromthe physical integration and miniaturization of electronic controllers withmechanical systems to the control of hydraulically powered robots inmanufacturing and assembling factories.Computer disk drives are one example of the successfulapplication of Mechatronics engineering as they are required to providevery fast access precise positioning and robustness against variousdisturbances.
An intelligent window shade that opens and closes according tothe amount of sun exposure is another example of a Mechatronicsapplication.Mechatronics engineering may be involved in the design ofequipments and robots for under water or mining exploration as analternative to using human beings where this may be dangerous. In factMechatronics engineers can be found working in a range of industriesand project areas including
•Design of data collection, instrumentation and computerizedmachine tools.
•Intelligent product design for example smart cars and automationfor household transportation and industrial application.
•Design of self-diagnostic machines, which fix problems on theirown.
•Medical devices such as life supporting systems, scanners andDNA sequencing automation.
•Robotics and space exploration equipments.
•Smart domestic consumer goods
•Computer peripherals.
•Security systems.
3.3 Mechatronic goals
3.3.1 The multisensory concept
The aim was to design a new generation of multi sensorylightweight robots. The new sensor and actuator generation does not onlyshow up a high degree of electronic and processor integration but alsofully modular hardware and software structures. Analog conditioning,power supply and digital pre-processing are typical subsystems modulesof this kind. The 20khz lines connecting all sensor and actuator systemsin a galvanically decoupled way and high speed optical serial data bus(SERCOS) are the typical examples of multi sensory and multi actuatorconcept for the new generation robot envisioned.The main sensory developments finished with these criteria havebeen in the last years: optically measuring force-torque-sensor forassembly operations. In a more compact form these sensory systemswere integrated inside plastic hollow balls, thus generating 6-degree offreedom hand controllers (the DLR control balls). The SPACE-MOUSEis the most recent product based on these ideas.
•stiff strain-gauge based 6 component force-torque-sensor systems.
•miniaturized triangulation based laser range finders.
•integrated inductive joint-torque-sensor for light-weight-robot.
In order to demonstrate the multi sensory design concept, thesetypes of sensors have been integrated into the multi sensory DLRgripper,which contains 15 sensory components and to our knowledge itis the most complex robot gripper built so far (more than 1000miniaturized electronic and about 400 mechanical components). It hasbecome a central element of the ROTEX space robot experiment.
SPACEMOUSE
Spacemouse is developed by the DLR institute of robotics andmechatronics.DLR- Deutsches Zenturum far Luft-und Raumfahrt
4.1 Why 3D motion?
In every area of technology, one can find automata and systemscontrollable up to six degrees of freedom- three translational and threerotational. Industrial robots made up the most prominent categoryneeding six degrees of freedom by maneuvering six joints to reach anypoint in their working space with a desired orientation. Even broaderthere have been a dramatic explosion in the growth of 3D computergraphics.Already in the early eighties, the first wire frame models of
volume objects could move smoothly and interactively using so calledknob-boxes on the fastest graphics machines available.
A separate buttoncontrolled each of the six degrees of freedom. Next, graphics systems onthe market allowed manipulation of shaded volume models smoothly,i.e. rotate, zoom and shift them and thus look at them from any viewingangle and position. The scenes become more and more complex; e.g.with a "reality engine" the mirror effects on volume car bodies areupdated several times per second - a task that needed hours on main frame computers a couple of years ago.Parallel to the rapid graphics development, we observed a cleartrend in the field of mechanical design towards constructing andmodeling new parts in a 3D environment and transferring the resultingprograms to NC machines. The machines are able to work in 5 or 6degrees of freedom (dot). Thus, it is no surprise that in the last few years,there are increasing demands for comfortable 3D control andmanipulation devices for these kinds of systems. Despite breathtakingadvancements in digital technology it turned out that digital manmachine
interfaces like keyboards are not well suited for people to use asour sensomotory reactions and behaviors are and will remain analogousforever.
4.2 DLR control ball, Magellan's predecessor
At the end of the seventies, the DLR (German Aerospace ResearchEstablishment) institute for robotics and system dynamics startedresearch on devices for the 6-dof control of robot grippers .in Cartesianspace. After lengthy experiments it turned out around 1981 thatintegrating a six axis force torque sensor (3 force, 3 torque components)into a plastic hollow ball was the optimal solution. Such a ball registeredthe linear and rotational displacements as generated by the forces torques of a human hand, which were then computationally transformedinto translational / rotational motion speeds.
The first force torque sensor used was based upon strain gaugetechnology, integrated into a plastic hollow ball. DLR had the basicconcept centre of a hollow ball handle approximately coinciding with themeasuring centre of an integrated 6 dof force / torque sensor patented in
Europe and US.From 1982-1985, the first prototype applications showed that DLR'scontrol ball was not only excellently suited as a control device for robots,but also for the first 3D-graphics system that came onto the market atthat time. Wide commercial distribution was prevented by the high salesprice of about $8,000 per unit. It took until 1985 for the DLR's developergroup to succeed in designing a much cheaper optical measuring system.
4.2.1 Basic principle
The new system used 6 one-dimensional position detectors. Thissystem received a worldwide patent. The basic principle is as follows.The measuring system consists of an inner and an outer part. Themeasuring arrangement in the inner ring is composed of the LED, a slit
and perpendicular to the slit on the opposite side of the ring a linearposition sensitive detector (PSD). The slit / LED combination is mobileagainst the remaining system. Six such systems (rotated by 60 degreeseach) are mounted in a plane, whereby the slits alternatively are vertical
and parallel to the plane. The ring with PSD's is fixed inside the outerpart and connected via springs with the LED-slit-basis. The springs bringthe inner part back to a neutral position when no forces / torque areexerted: There is a particularly simple and unique. This measuringsystem is drift-free and not subject to aging effects.
The whole electronics including computational processing on aone-chip-processor was already integrable into the ball by means of twosmall double sided surface mount device (SMD) boards, themanufacturing costs were reduced to below $1,000, but the sales pricestill hovered in the area of $3,000.
The original hopes of the developers group that the licensecompanies might be able to redevelop devices towards much lowermanufacturing costs did not materialize. On the other hand, with passingof time, other technologically comparable ball systems appeared on the
market especially in USA. They differed only in the type of measuringsystem. Around 1990, terms like cyberspace and virtual reality becamepopular. However, the effort required to steer oneself around in a virtualworld using helmet and glove tires one out quickly. Movements were
measured by electromagnetic or ultrasonic means, with the human headhaving problems in controlling translational speeds. In addition, movingthe hand around in free space leads to fairly fast fatigue. Thus a redesignof the ball idea seemed urgent.
4.3 Magellan (the European Spacemouse):
The result of a long development chain
With the developments explained in the previous sections, DLR'sdevelopment group started a transfer company, SPACE CONTROL andaddressed a clear goal: To redesign the control ball idea with itsunsurpassed opto electronic measuring system and optimize it thus thatto reduce manufacturing costs to a fraction of its previous amount andthus allow it to approach the pricing level of high quality PC mouse atleast long-term.
The new manipulation device would also be able to function as aconventional mouse and appear like one, yet maintain its versatility in areal workstation design environment. The result of an intense one-year'swork was the European SpaceMouse, in the USA it is especially in the
European market place. But end of 93, DLR and SPACE CONTROLjointly approached LOGITECH because of their wide expertise withpointing devices for computers to market and sell Magellan in USA andAsia.
The wear resistant and drift free opto electronic, 6 componentmeasuring system was ptimized to place all the electronics, includingthe analogous signal processing, AT conversion, computationalevaluation and power supply on only one side of a tiny SMD- boardinside Magellan's handling cap. It only needs a few milliamperes ofcurrent supplied through the serial port of any PC or standard mouseinterface. It does not need a dedicated power supply. The electroniccircuitry using a lot of time multiplex technology was simplified by afactor of five, compared to the former control balls mentioned before.The unbelievably tedious mechanical optimization, where the simpleadjustment of the PSD's with respect to the slits played a central role inits construction, finally led to 3 simple injection moulding parts, namelythe basic housing, a cap handle with the measuring system inside and thesmall nine button keyboard system.
The housing, a punched steel plateprovides Magellan with the necessary weight for stability; any kind ofmetal cutting was avoided. The small board inside the cap (including abeeper) takes diverse mechanical functions as well. For example, itcontains the automatically mountable springs as well as overloadprotection. The springs were optimized in the measuring system so thatthey no longer show hysteresis; nevertheless different stiffness of the capare realizable by selection of appropriate springs. Ergonomically,Magellan was constructed as flat as can be so that the human hand mayrest on it without fatigue.
Slight pressures of the fingers on the cap of Magellan is sufficientfor generating deflections in X, Y, and Z planes, thus shifting a cursor orflying a 3D graphics object translationally through space. Slight twists ofthe cap cause rotational motions of a 3D graphics object around thecorresponding axes. Pulling the cap in the Z direction corresponds tozooming function. Moving the cap in X or Y direction drags thehorizontally and vertically respectively on the screen. Twisting the capover one of the main axes or any combination of them rotates the object
over the corresponding axis on the screen.
The user can handle theobject on the screen a he were holding it in his own left hand and helpingthe right hand to undertake the constructive actions on specific pointslines or surfaces or simply by unconsciously bringing to the front ofappropriate perspective view of any necessary detail of the object. Withthe integration of nine additional key buttons any macro functions can bemapped onto one of the keys thus allowing the user most frequentfunction to be called by a slight finger touch from the left hand.
Thedevice has special features like dominant mode.It uses those degrees of freedom in which the greatest magnitudeis generated. So defined movements can be created. Connection to thecomputer is through a 3m cable (DB9 female) and platform adapter ifnecessary. Use of handshake signals (RTSSCTS) are recommended forthe safe operation of the spacemouse. Without these handshake signalsloss of data may occur. Additional signal lines are provided to power theMagellan (DTS&RTS). Thus, no additional power supply is needed.Flying an object in 6 dof is done intuitively without any strain. In asimilar way, flying oneself through a virtual world is just fun. Touchingthe keys results in either the usual menu selection, mode selection or thepickup of 3D objects.
MAGELLAN: FEATURES AND BENEFITS
5.1 Features
•Ease of use of manipulating objects in 3D applications.
•Calibration free sensor technology for high precision and uniquereliability.
•Nine programmable buttons to customize users preference formotion control
•Fingertip operation for maximum precision and performance.
•Settings to adjust sensitivity and motion control to the userspreference.
•Small form factor frees up the desk space.
•Double productivity of object manipulation in 3D applications.
•Natural hand position (resting on table) eliminates fatigue.
5.2 Benefits
As the user positions the 3D objects with the Magellan device thenecessity of going back and forth to the menu is eliminated. Drawingtimes is reduced by 20%-30% increasing overall productivity. With theMagellan device improved design comprehension is possible and earlier
detection of design errors contributing faster time to market and costsavings in the design process. Any computer whose graphics powerallows to update at least 5 frames per second of the designed scenery,and which has a standard RS232 interface, can make use of the fullpotential of Magellan spacemouse. In 3D applications Magellan is usedin conjunction with a 2D mouse. The user positions an object withspacemouse while working on the object using a mouse. We canconsider it as a workman holding an object in his left hand and workingon it with a tool in his right hand. Now Magellan spacemouse isbecoming something for standard input device for interactive motioncontrol of 3D graphics objects in its working environment and for manyother applications.
FUTURE SCOPE
Magellan's predecessor, DLR's control ball, was a key element ofthe first real robot inspace, ROTEX- (3), which was launched in April 93with space shuttle COLUMBIA inside a rack of the spacelab-D2. Therobot was directly teleoperated by the astronauts using the control ball,the same way remotely controlled from ground (on-line and off line)implying "predictive" stereographics. As an example, the groundoperator with one of the two balls or Magellans steered the robot'sgripper in the graphics presimulation, while with the second device hewas able to move the whole scenery around smoothly in 6 dot Predictivegraphics simulation together with the above mentioned man machineinteraction allowed for the compensation of overall signal delays up toseven seconds, the most spectacular accomplishment being the grasping
of a floating object in space from the ground. Since then, ROTEX hasoften been declared as the first real "virtual reality" application.
6.1.1 VISUAL SPACEMOUSE
A most intuitive controlling device would be a system that can beinstructed by watching and imitating the human user, using the hand asthe major controlling element. This would be a very comfortableinterface that allows the user to move a robot system in the most naturalway. This is called the visual space mouse. The system of the visualspace mouse can be divided into two main parts: image processing androbot control. The role of image processing is to perform operations on avideo signal, received by a video camera, to extract desired information
out of the video signal. The role of robot control is to transformelectronic commands into movements of the manipulator.
CHAPTER 7
CONCLUSION
The graphics simulation and manipulation of 3D volume objectsand virtual worlds and their combination e.g. with real information ascontained in TV images (multi-media) is not only meaningful for spacetechnology, but will strongly change the whole world of manufacturing
and construction technology, including other areas like urbandevelopment, chemistry, biology, and entertainment. For all theseapplications we believe there is no other man- machine interface
technology comparable to Magellan in its simplicity and yet highprecision. It is used for 3D manipulations in 6 dof, but at the same timemay function as a conventional 2D mouse.