JAVA ROBOTICS AND INTELLIGENT RESEARCH CENTER - Sri Lanka

Defining Parameters

2010-11-06T11:37:00.000-07:00

Number of axes – two axes are required to reach any point in a plane; three axes are required to reach any point in space. To fully control the orientation of the end of the arm (i.e. the wrist) three more axes (yaw, pitch, and roll) are required. Some designs (e.g. the SCARA robot) trade limitations in motion possibilities for cost, speed, and accuracy.
Degrees of freedom which is usually the same as the number of axes.
Working envelope – the region of space a robot can reach.
Kinematics – the actual arrangement of rigid members and joints in the robot, which determines the robot's possible motions. Classes of robot kinematics include articulated, cartesian, parallel and SCARA.
Carrying capacity or payload – how much weight a robot can lift.
Speed – how fast the robot can position the end of its arm. This may be defined in terms of the angular or linear speed of each axis or as a compound speed i.e. the speed of the end of the arm when all axes are moving.
Acceleration - how quickly an axis can accelerate. Since this is a limiting factor a robot may not be able to reach its specified maximum speed for movements over a short distance or a complex path requiring frequent changes of direction.
Accuracy – how closely a robot can reach a commanded position. When the absolute position of the robot is measured and compared to the commanded position the error is a measure of accuracy. Accuracy can be improved with external sensing for example a vision system or IR. See robot calibration. Accuracy can vary with speed and position within the working envelope and with payload (see compliance).
Repeatability - how well the robot will return to a programmed position. This is not the same as accuracy. It may be that when told to go to a certain X-Y-Z position that it gets only to within 1 mm of that position. This would be its accuracy which may be improved by calibration. But if that position is taught into controller memory and each time it is sent there it returns to within 0.1mm of the taught position then the repeatability will be within 0.1mm.
Accuracy and repeatability are different measures. Repeatability is usually the most important criterion for a robot. ISO 9283 sets out a method whereby both accuracy and repeatability can be measured. Typically a robot is sent to a taught position a number of times and the error is measured at each return to the position after visiting 4 other positions. Repeatability is then quantified using the standard deviation of those samples in all three dimensions. A typical robot can, of course make a positional error exceeding that and that could be a problem for the process. Moreover the repeatability is different in different parts of the working envelope and also changes with speed and payload. ISO 9283 specifies that accuracy and repeatability should be measured at maximum speed and at maximum payload. But this results in pessimistic values whereas the robot could be much more accurate and repeatable at light loads and speeds. Repeatability in an industrial process is also subject to the accuracy of the end effector, for example a gripper, and even to the design of the 'fingers' that match the gripper to the object being grasped. For example if a robot picks a screw by its head the screw could be at a random angle. A subsequent attempt to insert the screw into a hole could easily fail. These and similar scenarios can be improved with 'lead-ins' e.g. by making the entrance to the hole tapered.
Motion control – for some applications, such as simple pick-and-place assembly, the robot need merely return repeatably to a limited number of pre-taught positions. For more sophisticated applications, such as welding and finishing (spray painting), motion must be continuously controlled to follow a path in space, with controlled orientation and velocity.

Power source – some robots use electric motors, others use hydraulic actuators. The former are faster, the latter are stronger and advantageous in applications such as spray painting, where a spark could set off an explosion; however, low internal air-pressurisation of the arm can prevent ingress of flammable vapours as well as other contaminants.
Drive – some robots connect electric motors to the joints via gears; others connect the motor to the joint directly (direct drive). Using gears results in measurable 'backlash' which is free movement in an axis. Smaller robot arms frequently employ high speed, low torque DC motors, which generally require high gearing ratios; this has the disadvantage of backlash. In such cases the harmonic drive is often used.
Compliance - this is a measure of the amount in angle or distance that a robot axis will move when a force is applied to it. Because of compliance when a robot goes to a position carrying its maximum payload it will be at a position slightly lower than when it is carrying no payload. Compliance can also be responsible for overshoot when carrying high payloads in which case acceleration would need to be reduced.

ලොව මවිත කරන දැවැන්ත සමුළුවට ...

2010-11-05T08:39:00.001-07:00

Are You Ready?
ඔබ සූදානම්ද?

ලොව මවිත කරන දැවැන්ත සමුළුවට ...

2010-11-04T19:27:00.000-07:00

Are You Ready?
ඔබ සූදානම්ද?

ලොව මවිත කරන දැවැන්ත සමුළුවට ...

2010-11-03T07:06:00.000-07:00

Are You Ready?
ඔබ සූදානම්ද?

Photos of Java World Congress Press Conference

2010-11-02T11:41:00.000-07:00

Java World Congress | Press Conference | අපි සූදානම්...

2010-11-02T11:20:00.000-07:00

Java World Congress 2010 සහ Java Sri Lanka Exibition හි Press Conferrence (මාධ්‍ය සාකච්චාවක්) අද දින (2010-11-02) මාධ්‍යවේදීන් විශාල ප්‍රමාණයක් සහ ජාතික භාෂා සහ සමාජ ඒකාබද්ධතා අමාත්‍යංශයේ ගරු S.B නාවින්න ඇමතිතුමගේ සහ විද්‍යා හා තාක්ශණ අමාත්‍යංශයේ මහාචාර්ය තිස්ස විතාරණ සහ සමෘර්ධි අධිකාරියේ අධ්‍යෂක ජනරාල්තුමගේ සහභාගීත්වයෙන් පවත්වන ලදී.මෙහිදී Java World Congress හි සභාපති ඩිලන්ත විතානගේ සහ ගරු ලේකම් ආචාර්ය ඉෂාන්ත සිරිබද්දන මහත්වරුන් විසින් Java World Congress හි අරමුණ සහ ඉදිරි වැඩපිලිවෙල ඉතාමත් පැහැදිලිව ඉදිරිපත් කරන ලදී.

වැඩිදුර තොරතුරු සදහා...

History of Industrial Robotics

2010-11-02T10:47:00.000-07:00

George Devol applied for the first robotics patents in 1954 (granted in 1961). The first company to produce a robot was Unimation, founded by Devol andJoseph F. Engelberger in 1956, and was based on Devol's original patents. Unimation robots were also called programmable transfer machines since their main use at first was to transfer objects from one point to another, less than a dozen feet or so apart. They used hydraulic actuators and were programmed in joint coordinates, i.e. the angles of the various joints were stored during a teaching phase and replayed in operation. They were accurate to within 1/10,000 of an inch (note: although accuracy is not an appropriate measure for robots, usually evaluated in terms of repeatability - see later). Unimation later licensed their technology to Kawasaki Heavy Industries and Guest-Nettlefolds, manufacturing Unimates in Japan and England respectively. For some time Unimation's only competitor was Cincinnati Milacron Inc. of Ohio. This changed radically in the late 1970s when several big Japanese conglomerates began producing similar industrial robots.

In 1969 Victor Scheinman at Stanford University invented the Stanford arm, an all-electric, 6-axis articulated robot designed to permit an arm solution. This allowed it accurately to follow arbitrary paths in space and widened the potential use of the robot to more sophisticated applications such as assembly and welding. Scheinman then designed a second arm for theMIT AI Lab, called the "MIT arm." Scheinman, after receiving a fellowship from Unimation to develop his designs, sold those designs to Unimation who further developed them with support from General Motors and later marketed it as the Programmable Universal Machine for Assembly (PUMA).

Industrial robotics took off quite quickly in Europe, with both ABB Robotics and KUKA Robotics bringing robots to the market in 1973. ABB Robotics (formerly ASEA) introduced IRB 6, among the world's first commercially available all electric micro-processor controlled robot. The first two IRB 6 robots were sold to Magnusson in Sweden for grinding and polishing pipe bends and were installed in production in January 1974. Also in 1973 KUKA Robotics built its first robot, known as FAMULUS ^[2], also one of the first articulated robot to have six electromechanically driven axes.

Interest in robotics increased in the late 1970s and many US companies entered the field, including large firms like General Electric, and General Motors (which formed joint venture FANUC Robotics with FANUC LTD of Japan). U.S. startup companies included Automatix and Adept Technology, Inc. At the height of the robot boom in 1984, Unimation was acquired by Westinghouse Electric Corporation for 107 million U.S. dollars. Westinghouse sold Unimation to Stäubli Faverges SCA of France in 1988, which is still making articulated robots for general industrial and cleanroom applications and even bought the robotic division of Bosch in late 2004.

Only a few non-Japanese companies ultimately managed to survive in this market, the major ones being Adept Technology, Stäubli-Unimation, the Swedish-Swiss company ABB Asea Brown Boveri and the German company KUKA Robotics.

1954: The first programmable robot is designed by George Devol. He coins the term Universal Automation.
1956: Devol and engineer Joseph Engelberger form the world's first robot company, Unimation.
1960: Unimation is purchased by Condec Corporation and development of Unimate Robot Systems begins. American Machine and Foundry, later known as AMF Corporation, markets a robot, called the Versatran, designed by Harry Johnson and Veljko Milenkovic.
1962: The first industrial robot was online in a General Motors automobile factory in New Jersey. It was Devol and Engelberger's UNIMATE. It performed spot welding and extracted die castings.
1969: Nachi starts its robotic business.
1973: German robotics company, KUKA, creates the first industrial robot with six electromechanically-driven axes. It is called the Famulus.
1974: A robotic arm (the Silver Arm) that performed small-parts assembly using feedback from touch and pressure sensors was designed. Professor Scheinman, the developer of the Stanford Arm, forms Vicarm Inc. to market a version of the arm for industrial applications. The new arm is controlled by a minicomputer.
1974: Industrial robots were developed and installed in Fanuc factory. Dr. Inaba, President of FANUC was rewarded with "the 6th Annual Memorial Award of Joseph Marie Jacquard" by the American NC Society. The production and sale of DC servo motors were started under GETTYS MANUFACTURING CO., INC license.
1977: The Motoman L10 was introduced. It featured five axes and a maximum workload of 10 kg, which included the gripper. It weighed 470kg. The Motoman L10 was the first robot that Yaskawa introduced on the market.
1977: ASEA, a European robot company, offers two sizes of electric powered industrial robots. Both robots use a microcomputer controller for programming and operation. Unimation purchases Vicarm Inc. during this year.
1978: Vicarm, Unimation creates the PUMA (Programmable Universal Machine for Assembly) robot with support from General Motors. Many research labs still use this assembly robot.
1979: Nachi developed the first motor-driven robots for spot welding.
1979: OTC DAIHEN was known as OTC America. OTC was an acronym for the Osaka Transformer Company. Located in Charlotte, NC, OTC was originally a supplier of welding equipment for other transplant companies. They expanded to become a provider to the Japanese auto market of GMAW supplies. In these early years, OTC Japan introduced its first generation of dedicated arc welding robots.
1980: The industrial robot industry starts its rapid growth, with a new robot or company entering the market every month.
1981: Takeo Kanade builds the direct drive arm. It is the first to have motors installed directly into the joints of the arm. This change makes it faster and much more accurate than previous robotic arms.
1985: OTC DAIHEN became the official OEM supplier of robots to the Miller Electric Company. Miller chose to assign different model numbers to the robots sold in the North American market. The prefixed the letters in the model with "MR," for Miller Robot. Miller no longer supports the robots that were manufactured in this era. The Japanese models featured their own number and name.
1987: ASEA of Vasteras, Sweden (founded 1883) and BBC Brown Boveri Ltd of Baden, Switzerland, (founded 1891) announce plans to form ABB Asea Brown Boveri Ltd., headquartered in Zurich, Switzerland. Each parent will hold 50 percent of the new company.
1988: The Motoman ERC control system was introduced with the ability to control up to 12 axes, more than any other controller at the time.
1989: Nachi Technology Inc., U.S.A. is established.
1992: FANUC Robot School was established. GM Fanuc Robotics Corporation was restructured to FANUC's wholly owned share holding company, FANUC Robotics Corporation, together with its subsidiaries, FANUCRobotics North America, Inc. and FANUC Robotics Europe GmbH. A Prototype of the intelligent robot was built.
1994: The Motoman MRC control system was introduced with the ability to control up to 21 axes. It could also synchronize the motions of two robots.
1995: Miller departed from the robotic business. OTC launched the Dynamic Robotic Division and moved the headquarters to Ohio to focus on selling robots to new users.
1996: Nachi expands robotics business, cutting tool, and bearing product ranges.
1998: The introduction of the XRC controller allowed the control of up to 27 axes and the synchronized control of three to four robots. The Motoman UP series introduced a simpler robot arm that was more readily accessible for maintenance and repair. Honda was instrumental in driving the development of both the UP series of arms and the XRC arm control.
2003: OTC DAIHEN introduced the Almega AX series, a line of arc welding and handling robots. The AX series robots integrate seamlessly with the OTC D series welding power supplies for advanced control capabilities.

Robot Types

2010-11-02T10:26:00.000-07:00

The most commonly used robot configurations are articulated robots, SCARA robots and Cartesian coordinate robots, (aka gantry robots or x-y-z robots). In the context of general robotics, most types of robots would fall into the category of robotic arms (inherent in the use of the word manipulator in the above-mentioned ISO standard). Robots exhibit varying degrees of autonomy:

§ Some robots are programmed to faithfully carry out specific actions over and over again (repetitive actions) without variation and with a high degree of accuracy. These actions are determined by programmed routines that specify the direction, acceleration, velocity, deceleration, and distance of a series of coordinated motions.

§ Other robots are much more flexible as to the orientation of the object on which they are operating or even the task that has to be performed on the object itself, which the robot may even need to identify. For example, for more precise guidance, robots often contain machine vision sub-systems acting as their "eyes", linked to powerful computers or controllers. Artificial, or what passes for it, is becoming an increasingly important factor in the modern industrial robot.

Speech Recognition

2010-11-02T10:14:00.000-07:00

The Java Speech API (JSAPI) provides a simple yet powerful interface into speech systems -- including speech recognition and speech synthesis. "The Java Speech API doesn't actually provide the speech recognition and speech synthesis systems," explains Ritter. "It provides you with the programmatic interface into them."

There are several low-cost facilities that use the Java Speech API. "The applications I use for my demonstrations employ the IBM ViaVoice engine," notes Ritter. "It's been around for a few years now, and IBM has been very good to implement the Java Speech API -- which you can download from their AlphaWorks site for free." And the ViaVoice engine is very reasonably priced. For under $30, developers can be up and ready to build speech-enabled Java applications.

Key to JSAPI's speech recognition functionality is the command-and-control recognizer. "You specify certain words you want the system to recognize," says Ritter, "and indicate that you want to have an event sent to you when those words are recognized." The Java Speech API's Grammar Format allows you to define words that the system should recognize. "It provides us with a cross-platform way of controlling the speech recognizer," adds Ritter.

For More Information Visit http://java.sun.com/developer/technicalArticles/Programming/robotics/

Enter Java Robotics Technology

2010-11-02T10:11:00.000-07:00

The ability to hear, see, speak, and move is key to the human ability to manipulate the world. But to perform such human-like tasks, robotics systems must be able to emulate these functions via software. And when it comes to enabling robust, device-neutral, platform-neutral systems, Java technology virtually wrote the book. Java technology offers an array of APIs tailor-made to the needs of the robotics realm. The Java Speech API lets you build command-and-control recognizers, dictation systems, and speech synthesizers. And the Java Media Framework can be used to receive and process visual images.

Simon Ritter is a Technology Evangelist at Sun Microsystems. He speaks on many different aspects of Java technology, but is a particular champion of Java technology within the world of robotics. He has developed a Robotics Software Development Kit, and regularly gives compelling demonstrations of robotics systems using Java technology. Among these demonstrations are small, resource-constrained robots that use the LEGO Mindstorms RCX "brick." Ritter provides detailed directions (both hardware and software) for building, programming, and deploying his various LEGO robots.

For Ritter, the beauty of the standards-based Java technology APIs related to robotics is that they simplify development work -- allowing you to focus solely on the task at hand, rather than having to understand the entirety of a particular robotics system.

And lest anyone think that Java technology-powered robotics is unavailable outside the domain of enterprise developers, Ritter emphasizes that robotics speech synthesis engines are available for approximately $30, webcams can be had for well under $100, and the LEGO Mindstorms robot can be purchased for approximately $200!

For More Info Visit http://java.sun.com/developer/technicalArticles/Programming/robotics/ :)