Robot software

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Robot software is the set of coded commands that tell a mechanical device and electronic system, known together as a robot, what tasks to perform. Robot software is used to perform tasks and automate tasks. Many software systems and frameworks have been proposed to make programming robots easier.

Some robot software aims at developing intelligent mechanical devices. Common tasks include feedback loops, data filtering, control, pathfinding, and locating.

Introduction[edit]

Robot software is the coded commands that tell a mechanical device (known as a robot) what tasks to perform and control its actions. Robot software is used to perform tasks and automate tasks to be performed. Programming robots is a non-trivial task. Many software systems and frameworks have been proposed to make programming robots easier.

Some robot software aim at developing intelligent mechanical devices. Though common in science fiction stories, such programs are yet to become common-place in reality and much development is yet required in the field of artificial intelligence before they even begin to approach the science fiction possibilities. Pre-programmed hardware may include feedback loops such that it can interact with its environment, but does not display actual intelligence.

Data flow programming techniques are used by most robot manufacturers, and is based on the concept that when the value of a variable changes, the values of other variables affected should also change. A programming language that incorporates data flow principles is called a data flow language. In addition to numeric processing, data flow languages also incorporate functional concepts. Unlike other programming languages which use imperative programming, data flow programming is modeled as a sequence of functions.

With any programming software, the state of a program at any given time is an important consideration. The state provides an indication of the various conditions at a particular instant. In order to function properly, most programming languages require a significant amount of state information. This information is invisible to the programmer.

Another key concept – which is associated with any type of robot programming, is the concept of run-time. When a program is running, or executing, it is said to be in run-time. The term run-time is also used as a short form when referring to a run-time library, which is a library of code instructions used by a computer language to manage a program written in the language. The term is also used by software developers to specify when errors in a program can occur. A runtime error is an error that happens while the program is executing. For example, if a robot arm was programmed to turn left, and it turned right, then that would be a runtime error.

The software architecture of a system consists of the various software components used to design and operate the software. All programming methods rely on software architecture as a method of organizing a software system since it not only provides communication support but is also a critical component in hardware and software interfaces.

Industrial Robot Software[edit]

Software for industrial robots consists of data objects and lists of instructions, known as program flow (list of instructions). For example

Go to Jig1

is an instruction to the robot to go to positional data named Jig1. Of course programs can also contain implicit data for example

Tell axis 1 move 30 degrees.

Data and program usually reside in separate sections of the robot controller memory. One can change the data without changing the program and vice versa. For example one can write a different program using the same Jig1 or one can adjust the position of Jig1 without changing the programs that use it.

Examples of programming languages for Industrial Robots[edit]

Due to the highly proprietary nature of robot software, most manufacturers of robot hardware also provide their own software. While this is not unusual in other automated control systems, the lack of standardization of programming methods for robots does pose certain challenges. For example, there are over 30 different manufacturers of industrial robots, so there are also 30 different robot programming languages required. Fortunately, there are enough similarities between the different robots that it is possible to gain a broad-based understanding of robot programming without having to learn each manufacturer's proprietary language.

Some examples of published robot programming languages are shown below.

Task in plain English:

Move to P1 (a general safe position)
Move to P2 (an approach to P3)
Move to P3 (a position to pick the object)
Close gripper
Move to P4 (an approach to P5)
Move to P5 (a position to place the object)
Open gripper
Move to P1 and finish

VAL was one of the first robot ‘languages’ and was used in Unimate robots. Variants of VAL have been used by other manufacturers including Adept Technology. Stäubli currently use VAL3.

Example program:

PROGRAM PICKPLACE
  1. MOVE P1
  2. MOVE P2
  3. MOVE P3
  4. CLOSEI 0.00
  5. MOVE P4
  6. MOVE P5
  7. OPENI 0.00
  8. MOVE P1
.END

Epson RC+ (example for a vacuum pickup)

Function PickPlace
       Jump P1
       Jump P2
       Jump P3
       On vacuum
       Wait .1
       Jump P4
       Jump P5
       Off vacuum
       Wait .1
       Jump P1
Fend

ROBOFORTH (a language based on FORTH).

: PICKPLACE
P1
P3 GRIP WITHDRAW
P5 UNGRIP WITHDRAW
P1
;

(With Roboforth you can specify approach positions for places so you do not need P2 and P4.)

Clearly the robot should not continue the next move until the gripper is completely closed. Confirmation or allowed time is implicit in the above examples of CLOSEI and GRIP whereas the On vacuum command requires a time delay to ensure satisfactory suction.

Other robot programming languages[edit]

Visual programming language[edit]

The software system for the Lego Mindstorms NXT robots is worthy of mention. It is a graphical user interface (GUI) written with LabVIEW. The approach is to start with the program rather than the data. The program is constructed by dragging icons into the program area and adding or inserting into the sequence. For each icon you then specify the parameters (data). For example for the motor drive icon you specify which motors and by how much they move. When the program is written it is downloaded into the Lego NXT 'brick' (microcontroller) for test.

Scripting Languages[edit]

A scripting language is a high-level programming language that is used to control the software application, and is interpreted in real-time, or "translated on the fly", instead of being compiled in advance. A scripting language may be a general-purpose programming language or it may be limited to specific functions used to augment the running of an application or system program. Some scripting languages, such as RoboLogix, have data objects residing in registers, and the program flow represents the list of instructions, or instruction set, that is used to program the robot.

Programming languages are generally designed for building data structures and algorithms from scratch, while scripting languages are intended more for connecting, or “gluing”, components and instructions together. Consequently, the scripting language instruction set is usually a streamlined list of program commands that are used to simplify the programming process and provide rapid application development.

Parallel languages[edit]

Another interesting approach is worthy of mention. All robotic applications need parallelism and event-based programming. Parallelism is where the robot does two or more things at the same time. This requires appropriate hardware and software. Most programming languages rely on threads or complex abstraction classes to handle parallelism and the complexity that comes with it, like concurrent access to shared resources. URBI provides a higher level of abstraction by integrating parallelism and events in the core of the language semantics.

whenever(face.visible)
{
  headPan.val  += camera.xfov * face.x
  &
  headTilt.val += camera.yfov * face.y
}

The above code will move the headPan and headTilt motors in parallel to make the robot head follow the human face visible on the video taken by its camera whenever a face is seen by the robot.

Robot application software[edit]

Regardless which language is used, the end result of robot software is to create robotic applications that help or entertain people. Applications include command-and-control and tasking software. Command-and-control software includes robot control GUIs for tele-operated robots, point-n-click command software for autonomous robots, and scheduling software for mobile robots in factories. Tasking software includes simple drag-n-drop interfaces for setting up delivery routes, security patrols and visitor tours; it also includes custom programs written to deploy specific applications. General purpose robot application software is deployed on widely distributed robotic platforms.

Safety Considerations[edit]

Programming errors represent a serious safety consideration, particularly in large industrial robots. The power and size of industrial robots mean they are capable of inflicting severe injury if programmed incorrectly or used in an unsafe manner. Due to the mass and high-speeds of industrial robots, it is always unsafe for a human to remain in the work area of the robot during automatic operation. The system can begin motion at unexpected times and a human will be unable to react quickly enough in many situations, even if prepared to do so. Thus, even if the software is free of programming errors, great care must be taken to make an industrial robot safe for human workers or human interaction, such as loading or unloading parts, clearing a part jam, or performing maintenance. The ANSI/RIA R15.06-1999 American National Standard for Industrial Robots and Robot Systems - Safety Requirements (revision of ANSI/RIA R15.06-1992) book from the Robotic Industries Association is the accepted standard on robot safety. This includes guidelines for both the design of industrial robots, and the implementation or integration and use of industrial robots on the factory floor. Numerous safety concepts such as safety controllers, maximum speed during a teach mode, and use of physical barriers are covered.

Robotics Software Projects[edit]

The following is a list of open source and free software for robotics projects.

  • CLARAty - Coupled-Layer Architecture for Robotic Autonomy. It is a collaborative effort among four institutions: NASA Jet Propulsion Laboratory, NASA Ames Research Center, Carnegie Mellon, and the University of Minnesota.
  • dLife - Free/Open Source Java library for Robotics, AI and Vision. Supports Pioneer, Khepera II & II, Hemission, Aibo and Finch robots as well as Player/Stage simulations.
  • Experimental Robotics Framework - A software for making experiments with multiple robots in 3d, with support for the latest technologies, that sits on top of Player/Stage and Open/CV.
  • MARIE - Mobile and Autonomous Robotics Integration Environment - is a Free Software using a component-based approach to build robotics software systems by integrating previously-existing and new software components.
  • Microsoft - Microsoft Robotics Developer Studio
  • OpenRDK - An open-source software framework for robotics for developing loosely-coupled modules. It provides transparent concurrency management, inter-process (via sockets) and intra-process (via shared memory) blackboard-based communication and a linking technique that allows for input/output data ports conceptual system design. Modules for connecting to simulators and generic robot drivers are provided.
  • OpenRTM-aist - a software platform developed on the basis of the RT middleware standard. It is developed by National Institute of Advanced Industrial Science and Technology in Japan.
  • OROCOS - the Open Robot Control Software project provides a Free Software toolkit for realtime robot arm and machine tool control.
  • Robotics Library is an open-source C++ library covering kinematics, planning, visualization, and hardware drivers for several robots.
  • Robotics Toolbox for MATLAB - this is Free Software that provides functionality for representing pose (homogeneous transformations, Euler and RPY angles, quaternions), arm robots (forward/inverse kinematics and dynamics) and mobile robots (control, localisation and planning)
  • Player/Stage Project - A very popular Free Software robot interface and simulation system, used for robotics research and teaching worldwide.
  • Pyro, Python Robotics - Popular robotics Free Software used in universities and colleges.
  • RoboMind - Educational software to learn the basics of robotics and programming.
  • Robot Operating System - Robot Operating System is an open-source platform for robot programming using Python and C++. Java, Lisp, Lua and Pharo are supported but still in experimental stage.
  • Robot Intelligence Kernel

See also[edit]

External links[edit]