Robot Assembly and Programming Prelim

Robotics

Art, knowledge base, and know-how of designing, applying, and using robots in human endeavors.

ISO 8373

"An automatically controlled, reprogrammable, multipurpose manipulator with three or more axes."

 Robot Institute of America

“A reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through various programmed motions for the performance of various tasks."

Merriam-Webster Dictionary

"A machine that looks like a human being and performs various complex acts (as walking or talking) of a human being."

Karel Čapek

Wrote the play Rossum's Universal Robots, in which the theme is one of futuristic man-made workers created to automate the work of humans, thus alleviating their burden.

Robotnik

Refers to a peasant or serf

Robota

Means drudgery or servitude.

Zeroth Law

A robot may not injure humanity or, through inaction, allow humanity to come to harm.

First Law

 A robot may not injure a human being or, through inaction, allow a human being to come to harm unless this would violate a higher-order law.

Second Law

A robot must obey the orders given to it by human beings, except where such orders would conflict with a higher order law.

Third Law

A robot must protect its own existence, as long as such protection does not conflict with a higher order law

Fixed-sequence robot

 A device that performs the successive stages of a task according to a predetermined, unchanging method that is hard to modify.

Playback robot

 A human operator performs a task manually by leading the robot, which records the motions for later playback. The robot repeats the same motions according to the recorded information.

Numerical-control robot

The operator supplies the robot with a movement program rather than teaching it the task manually.

Intelligent robot

A robot with the means to understand its environment and the ability to successfully complete a task despite changes in the surrounding conditions under which it is to be performed.

Effectors

Are the robot's appendages that move or move it, such as legs, arms, necks, and wrists. Effectors enable a robot to act on the environment. The major effectors in a ground robot are the wheels, tracks, or legs that give it navigational mobility. A new spate of work in robotics is centered on robot manipulators, essentially robot hands and arms.

Perception

Set of sensors and sensing that provide a robot with the equivalent of eyes, ears, nose, smell, and touch. It generally requires a sensor, the device that collects a signal, and algorithms to interpret it. Perception is how a robot senses the environment.

Control

Analogous to the central nervous system, where a computer processor(s) provides the robot's inner and outer loop control. The control component contains the computations that allow an intelligent robot to maximize its chances of success.

Communication

A robot interacts with other agents if only the robot operator allows the exchange of information with other entities.

Power

Enables other functions; it duplicates the role of food and the digestive system in animals.

Manipulator or rover.

The robot's main body consists of the links, joints, and other structural elements. Without other elements, the manipulator alone is not a robot.

End effector

This part is connected to the last joint (hand) of a manipulator and generally handles objects, makes connections to other machines, or performs required tasks.

Actuators

Are the "muscles" of the manipulators. The controller sends signals to the actuators, which move the robot's joints and links.

Sensors

Used to collect information about the robot's internal state or communicate with the outside environment.

Controller

Similar to a cerebellum; although it does not have the brain's power, it still controls motions.

Processor

The brain of the robot. It calculates the motions of the robot's joints based on the programs it runs, determines how much and how fast each joint must move to achieve the desired location and speeds, and oversees the coordinated actions of the controller and the sensors.

Software

Three groups of software programs are used in a robot.

Robot movement

A  concept commonly used in robotics, mechanics, and physics to describe the number of independent ways in which an object can move or change its configuration.

Link

Refers to a rigid component of a robot that connects two or more joints.

Joint

Refers to the mechanism that connects two adjacent links in a robot, allowing them to rotate or translate relative to each other.

Robot's configuration

A complete specification of the positions and orientations of each link of a robot, and its configuration space is the set of all possible configurations of the robot

Degrees of freedom (DOF)

The minimum number of independent parameters required to specify the position and orientation of each link based on the robot's configuration.

Revolute joint R (hinge joint)

Allows for rotational motion about the joint axis. (1 DOF)

Prismatic joint P (sliding or linear joint)

Allows for translational (or rectilinear) motion along the direction of the joint axis. (1 DOF) 

Screw joint H (helical joint)

Allows simultaneous rotation and translation about a screw axis. (1 DOF)

Cylindrical joint C

Allows for independent translations and rotations about a single fixed joint axis. (2 DOF)

Universal joint U

Consists of a pair of revolute joints arranged in which their joint axes are orthogonal. (2 DOF)

Spherical joint S (ball-and-socket joint)

Has three degrees of freedom and functions like our shoulder joint. (3 DOF)

Robot Coordinates

It refers to a system of defining and measuring the position and orientation of a robot in each space or environment.

Cartesian/rectangular/gantry (3P)

These robots use three prismatic joints to position the end effector, usually followed by additional revolute joints that orient the end effector.

Cylindrical (PRP)

Cylindrical coordinate robots have two prismatic joints, one revolute joint for positioning the part and revolute joints for orientation.

Spherical (P2R)

Spherical coordinate robots follow a spherical coordinate system with one prismatic and two revolute joints for positioning the part, plus additional revolute joints for orientation.

Articulated/anthropomorphic (3R)

An articulated robot's joints are all revolute, like a human's arm. They are the most common configuration for industrial robots.

Selective Compliance Assembly Robot Arm (SCARA)

Have two (or three) revolute joints that are parallel and allow the robot to move in a horizontal plane, plus an additional prismatic joint that moves vertically. SCARA robots are very common in assembly operations.

World reference frame

This is a universal coordinate frame defined by x-, y-, and z-axes. In this case, the joints of the robot move simultaneously in a coordinated manner to create motions along the three major axes.

Joint reference frame

This is used to specify the movements of individual joints of the robot. In this case, each joint is accessed and moved individually; therefore, only one joint moves at a time.

Tool reference frame

This specifies movements of the robot's hand relative to a frame attached to the hand; consequently, all motions are relative to this local n, o, a-frame. Unlike the universal World frame, the local Tool frame moves with the robot.

Physical setup

In this mode, an operator sets up switches and hard stops that control the motions of the robot. This mode is usually used along with other devices, such as programmable logic controllers (PLCs).

Lead-through or teach mode

In this mode, the robot's joints are moved with a teach pendant. When the desired location and orientation are achieved, the location is entered (taught) into the controller.

Continuous walk-through mode

In this mode, all robot joints are moved simultaneously while the motion is continuously sampled and recorded by the controller.

Software mode

In this mode, a program is written offline or online and is executed by the controller to control the motions. The programming mode is the most sophisticated and versatile mode and can include sensory information, conditional statements, and branching.

Microcomputer machine language level

At this level, programs are written in machine language. This level of programming is the most basic and is very efficient, but it is difficult to understand and difficult for others to follow.

Point-to-point level

At this level, the coordinates of the points are entered sequentially, and the robot follows the points as specified. This is a very primitive and simple type of program and is easy to use but not very powerful

Primitive motion level

In these languages, it is possible to develop more sophisticated programs, including sensory information, branching, and conditional statements. Most languages at this level are interpreter-based.

Structured programming level

Most languages at this level are compiler-based, are powerful, and allow more sophisticated programming. However, they are also more difficult to learn.

Task-oriented level

There are no actual languages in existence at this level - yet. Instead of programming a robot to perform a task by programming every step, the user would only mention the task, expecting that the controller would create the necessary sequence.

Machine loading

Robots supply other machines with parts or remove the processed parts from other machines.

Pick and place operations

The robot picks up parts and places them elsewhere. This may include palletizing, placement of cartridges, simple assembly where two parts are put together (such as placing tablets into a bottle), placing parts in an oven, removing the treated parts from the oven, or other similar routines.

Welding

 The robot, along with proper setups and a welding end effector, is used to weld parts together. This is one of the most common applications of robots in the auto industry. Due to their consistent movements, robotic welds are very uniform and accurate.

Painting

Another very common application of robots, especially in the automobile industry. Since maintaining a ventilated but clean paint area suitable for humans is difficult to achieve, and because compared to humans' robotic operations are more consistent, painting robots are very well-suited for their job

Inspection of parts

A very common application for robots. In general, robots are one component of an inspection system that may include a vision system, an X-ray device, an ultrasonic detector, or other similar devices.

Assembly tasks

Usually involve many operations. Many of the fitting and assembling tasks are complicated and may require pushing, turning, bending, wiggling, pressing, snapping tabs to connect the parts, and other operations.

Manufacturing

Include many different operations, such as material removal, drilling, deburring, laying glue, cutting, and so on. It also includes the insertion of parts, such as electronic components into circuit boards, installation of boards into electronic devices, and other similar operations. Insertion robots are very common and are extensively used in the electronic industry. Figure 1.14 shows a robot engaged in manufacturing.

Medical applications

Also becoming increasingly common, such as surgical robots, which are not really robots because they are operated by a surgeon rather than operating on their own. No robot knows how to perform surgery yet. These precision robots assist surgeons in performing surgery.

Assisting disabled individuals

Also been tried with interesting results. Robots are well suited to help the disabled and elderly in many ways, and many humanoid robots under development can be excellent choices for this purpose. In addition, many exoskeleton devices have been developed to help paraplegic persons walk.

Hazardous environments

Because of their inherent danger in these environments, humans must be well-protected. However, robots can access, traverse, maintain, and explore these areas without the same level of concern.

Inaccessible locations

Such as space, underwater, and mines, can also be serviced or explored by robots. Examples of these are underwater robots, which have also looked for, found, and explored sunken ships in deep oceans.

Robots in agriculture

Can be very useful, especially in places where labor shortage or environmental conditions are important issues. Robotic pickers have been developed and tested around the world and are becoming more common.