Introduction to Robotics 201

"Introduction to Robotics" describes the basics of industrial robotics, including types, applications, and programming methods. Industrial robots are reprogrammable machines that can perform repetitive or dangerous tasks with a high degree of accuracy. Manufacturers increasingly use robots to perform such tasks in order to speed up production, improve part quality, and preserve operator safety. However, robots require human engineers and operators to program, maintain, repair, and oversee them.

Industrial robots are highly complex machines that come in a number of types, including stationary robots and mobile robots. These robots are made of a number of intricate components that must be assembled and maintained properly. Similarly, all robots must be programmed to perform a task, and that programming can require adjusting. After taking this class, students will know the basic robot components, type, applications, and programming methods, as well as safety protocols.

Class Details

Class Name:
Introduction to Robotics 201
Version:
2.0
Difficulty:
Advanced
Number of Lessons:
21
Related 1.0 Class:
Intro to Robotics 110

Class Outline

  • Industrial Robots
  • Industrial Robot Characteristics
  • Basic Components of Industrial Robots
  • Axes
  • Degrees of Freedom
  • Coordinate Systems
  • Joints
  • Basic Robot Components and Movement Review
  • Stationary and Mobile Industrial Robots
  • Types of Mobile Robots
  • Robotic Arms
  • Serial and Parallel Robotic Arms
  • Types of Robotic Arms
  • Robot Joints and Types Review
  • Welding Applications
  • Material-Handling Applications
  • Additional Industrial Robot Applications
  • Artificial Intelligence
  • Robot Programming Methods
  • Robot Safety
  • Robot Applications, Teaching, and Safety Review

Objectives

  • Describe industrial robots.
  • Describe the different characteristics of industrial robots.
  • Describe the basic components of industrial robots.
  • Describe the axes that define robotic movement.
  • Describe the different degrees of freedom that enable robotic movement.
  • Describe the different coordinate systems used to program robotic movements.
  • Describe the different types of joints an industrial robot may have.
  • Describe the different categories of industrial robots.
  • Describe the different types of mobile industrial robots.
  • Describe robotic arms.
  • Describe serial and parallel robotic arms.
  • Describe the different types of robotic arms.
  • Describe the welding applications of industrial robots.
  • Describe material-handling applications of robots.
  • Describe the additional industrial robot applications.
  • Describe artificial intelligence and its use in robotics.
  • Describe the different robot programming methods.
  • Describe safety precautions for working with robots.

Job Roles

Certifications

Glossary

Vocabulary Term Definition
a axis An axis that travels around the x axis. The a axis is one of the three rotational axes that allow for complex machine movement.
abrasives A material consisting of hard particles used to wear away or remove workpiece material. Abrasives are used in operations designed to clean, polish, or otherwise prepare the surface of a part, such as shot blasting or glass-bead peening.
accuracy The ability to reach an exact set position. Accuracy is measured by precision, or how closely the physical robot positions itself to the programmed location.
actuators A device that activates movement in either a linear or rotary fashion. Actuators can be motors at the joint between linkages or be the linkage, such as a hydraulic cylinder or other linear drive mechanism.
additive manufacturing AM. The process of successively layering materials to make an object based on a three-dimensional computer model. Additive manufacturing, sometimes called three-dimensional (3D) printing, is sometimes accomplished using delta robots, which can move with the precision and accuracy required by the process.
algorithm A logic and mathematical expression that models a process or action. Algorithms are coded into a computer program that forms the rules by which a robot will interface with its environment.
algorithms A set of equations and programs in a computer. Algorithms help robots act according to the activity in their environments.
American National Standards Institute ANSI. A private, nonprofit organization that administers and coordinates voluntary standards and systems. The American National Standards Institute also provides robot safety guidelines.
arc welding A joining process that uses electricity to generate the heat needed to melt the base materials. Arc welding is portable and economical, making it the most common form of welding in industrial applications.
articulated robots Robots that closely resemble human arms. The arm of an articulated robot must have at least three revolute joints.
artificial intelligence AI. A computer program that contains algorithms that function as behavioral rules. Artificial intelligence has software that provides the robot the ability to discern and learn from its experiences in order to make optimized decisions during the operation or for subsequent processes.
assembly Applications that require robots to fit and connect components in order to make a completed part from those components. Assembly robots are fast, consistent, and effectively self-inspect their work.
automated guided carts AGCs. An inexpensive powered vehicle that carries material along a track on a factory floor. Automated guided carts, also known as cart vehicles, are not programmable and serve only as material movers.
automated guided vehicles AGVs. A programmable, highly sophisticated autonomous vehicle, often integrated with sensor technology, that transports pallets of material. Automated guided vehicles, also known as unit load carriers, have a powered deck that can lift, lower, and sometimes rotate the pallet.
axes An imaginary line that passes through the center of an object. Axes are used to define positions in the Cartesian coordinate system.
b axis An axis that travels around the y axis. The b axis is one of the three rotational axes that allow for complex machine movement.
base The section of the robot that makes contact, and is usually secured, to the ground or a fixture. The robot base serves as a foundation on which the rest of the components are built.
base coordinate systems A positioning system where the origin is set at the base of a robot. The base coordinate system is particularly useful for precisely adjusting the position of a floor-mounted unit since the base position is physically fixed.
body The casing and other devices that provide structural support for the other components in the robot. The body shape of a robot will vary greatly depending on the type of robot.
breakage The fracture of part or all of a part, tool, or other component. Breakage of manufacturing tools can be monitored by machine-tending robots.
c axis An axis that travels around the z axis. The c axis is one of the three rotational axes that allow for complex machine movement.
cantilever A long, rigid component fixed at only one end. Cantilever links and structures in robot arms provide more flexibility but less rigidity.
cart vehicles An inexpensive powered vehicle that carries material along a track on a factory floor. Cart vehicles, also known as automated guided carts (AGCs), are not programmable and serve only as material movers.
Cartesian coordinate system A positioning system that uses three linear axes perpendicular to each other to locate positions in three-dimensional space. The three axes in the Cartesian coordinate system are the x axis, y axis, and z axis.
Cartesian robots A type of robot that has only prismatic joints. Cartesian robots move in straight lines.
clean room A room in which temperature, humidity, and air pressure are controlled and maintained. Robots are ideal for use in clean rooms because they do not contaminate the clean room environment.
controller A processor-driven device that uses logic-based software to function. Controllers translate the human input commands from the input device into computer code that then controls and directs all the functions of the robot.
conveyor belt A moving strip of material that carries parts or other components from one area of a manufacturing facility to another. Conveyor belts are commonly used to transport parts from production to packaging.
cycle The completion of an entire programmed task or process. Robot cycles can be short, such as placing one component in a part, or long, such as assembling a complex part from small components.
cycle times The actual time it takes to perform a task before moving to the next step of a process. Cycle times are typically decreased when industrial robots are used in welding operations.
cylindrical coordinate system A positioning system that determines the placement of a point within a cylindrical envelope based on its relationship to the radial distance (p), the azimuth (φ), and the height, or longitudinal axis, (z). The cylindrical coordinate system is most often used when programming Selective Compliance Assembly Robot Arm robots (SCARA robots).
cylindrical robots A robotic arm that has a combination of revolute and prismatic joints. Cylindrical robots have a work envelope that is cylindrical and move mostly in circular paths.
data Information, often in the form of readable alphanumeric characters, that is used for serializing, analyzing, and problem solving. Data is used in many processing applications, such as tracking parts, assessing part quality, and modifying the process to maintain quality standards.
degrees of freedom The ability to move in a specific direction in three-dimensional space along or around an axis. Industrial robots typically have a maximum of six degrees of freedom, along the three linear axes and around the three rotational axes.
delta robots A stationary, high-speed parallel robot. Delta robots are usually suspended above their work area and have three parallel arms that attached together with an end effector and driven by motors in the base of the robot.
dispensing Distributing or applying materials into containers or onto surfaces. Dispensing also includes blasting materials at a surface for cleaning purposes.
drive An electronic device that takes the command signals from the controller and then controls the acceleration and deceleration, speed, and power of an electric motor. In robots, drives are connected to electric motors.
drive system A system that makes a robot move. Drive systems are made up of motors and drives.
drones A compact mobile robot that can be guided through programming or the use of a remote control. Drones can fly, swim, or, sometimes, fly and swim.
electric motors A drive system that uses power created by electricity to run. Electric motors can be used to power robots.
electrical energy A form of energy created by the movement of electrons. Electrical energy can be converted into light, heat, or, through the use of motors and drives, into motion.
emergency stops E-stop. A pushbutton that, when pressed, should bring a machine to a safe, rapid stop. Emergency-stop buttons can be located in multiple places around a robotic operation and are always found on robot teach pendants, and they must be unlocked after being pressed.
end effector A device attached to the end of the robot arm in order to interact with a part, component, or material. The end effector, also known as an end-of-arm tool (EOAT), may be a gripper that allows the robot to pick up objects and place them down, or it may be a welding torch or tool, such as a grinder, that performs a manufacturing task.
end-of-arm tool EOAT. A device attached to the end of the robot arm in order to interact with a part, component, or material. The end-of-arm tool, also known as an end effector, may be a gripper that allows the robot to pick up objects and place them down, or it may be a welding torch or tool, such as a a grinder, that performs a manufacturing task.
engineers A person responsible for ensuring that a manufacturing machine or process runs efficiently and safely. Engineers are generally in charge of designing a robotic manufacturing setup, programming robots, evaluating their performance, troubleshooting, and performing any repair operations.
fork-lift vehicles A programmable autonomous vehicle, most often used in warehousing applications where they transport materials by taking and stacking and locating and retrieving. Fork-lift vehicles are often combined with sensor technology in order to optimize a warehouse operation.
foundation The support and reinforcement at the base of the robot. Foundation size and type, such as bolts in concrete, help determine the ultimate load that a robot can safely support.
glass-bead peening A cold-working method where glass beads are shot at the surface of a workpiece at a high velocity. Glass-bead peening increases the fatigue strength and stress-crack corrosion resistance of a workpiece's surface.
grippers An end effector that mimics the function of the human hand. Grippers are a very common type of end effector.
grit blasting A surface conditioning process where a fine abrasive material is forced through a nozzle with compressed air and aimed at the surface of a workpiece. Grit blasting, sometimes called sand blasting, is used to clean surfaces that show corrosion or have unwanted coatings or paint, in preparation for a subsequent process.
hazards A source of danger or possible injury. Hazards can be physical hazards, such as falling objects, or health hazards, such as chemical exposures.
home position The datum position, usually zero on every axis, where a robot calibrates its start position. The home position may be where some robots will begin and end a cycle or program.
human error A failure in a manufacturing process as a result of an engineer or operator being tired, lacking fine motor skills, or losing concentration. Human errors are reduced through the use of robots, though not completely eliminated because humans program robots.
human-robot collaboration HRC. A manufacturing process where a human operator and a robot work closely together to complete the task. Human-robot collaboration is a growing robot application as it allows for more flexibility in the use of robots while improving the efficiency of an operation.
hydraulic motors A drive system that uses power created by fluids to run. Hydraulic motors can be used to power robots.
hydraulic pumps A mechanical power source that creates fluid flow and moves fluid through a hydraulic system. Hydraulic pumps receive energy from a prime mover, such as a motor or an engine.
industrial robots A reprogrammable machine sometimes used in place of a human being. Industrial robots, commonly used in manufacturing, perform dangerous or repetitive tasks with a high degree of accuracy.
input device A device that allows a human being to communicate with and program the robot. Input devices include keyboards and teach pendants.
input signals Feedback signals from the robot sensors in an input/output module. Input signals in robotic systems are processed by the controller that subsequently sends output signals to the robot to modify the operation of an autonomous robot system.
input/output module The interface between the robot and the robot controller. The input/output module uses the output from the controller and provides instructions to the robot and the module receives input feedback from the robot sensors that will then modify the subsequent output.
inspection The examination of a part during or after its creation to confirm that it adheres to specifications. Inspection can be accomplished by robots with great accuracy, speed, and precision.
inspection station A location where personnel examine a part to determine if it meets specifications. Inspection stations ensure that parts will function correctly when they are put in an assembly or delivered to a customer.
joints A connecting component on a robot that can move through an angle about a center point. Joints on a robot mimic the movement of human joints, such as a wrist or elbow, with the ability to rotate.
lag time The interval between two events. Lag time in manufacturing refers to the delay between two steps in a production process, which can be reduced through the use of robots.
lead-through programming A programming method where operators physically take a robot through the steps of a manufacturing operation. Lead-through programming, also known as walk-through programming, is a type of online programming.
legged robots A robot that uses appendages to move. Legged robots are types of mobile robots.
linear actuators A mechanical device that converts energy into motion along a straight line. Linear actuators may be used solely or in combination with motors to move the component parts of the robot in order to position the end effector.
linear axes An axis that defines side-to-side, front-to-back, or up-and-down movement. Linear axes include the x, y, and z axes.
linear movement Movement along a straight line. Cartesian robots can only make linear movements.
linkages A series of rigid mechanical devices that are connected with movable joints to provide movement in a system. In some robot designs, a linear actuator might be the linkage that is used to provide the movement.
links A rigid body between two joints. Link movement is actuated by motors in the joints or, in some cases, the link can be the actuator.
lockout/tagout A method of protecting employees from accidental machine startup through proper locking and labeling of machines that are hazardous to nearby employees. Lockout/tagout is an essential practice for safe repair of machines, including robots.
machine interface The input device on a machine that engineers and operators use to interact with the machine's control system. The machine interface may be complex, such as a computer touchscreen, or simple, such as a control panel with just a few buttons.
machine-tending Loading and unloading of materials into machinery for processing. Machine-tending robots are precise and often interact with the process using sensors to monitor the process and part quality.
magnetic strip A thin tape that can be bonded to the floor and contains ferrous materials that can be magnetized to provide a guide path. Magnetic strips are used as tracks for cart vehicles, or automated guided carts (AGCs).
material-handling Loading, unloading, placing, or manipulating materials. Types of material-handling tasks include machine tending, part transfers, packaging, and palletizing.
metal inert gas welding MIG welding. An arc welding process that uses electricity to strike an arc between a continuous feed of wire and the workpiece. In metal inert gas welding, which is one of the most common forms of robotic welding, the nozzle supplies a shield of inert gas to prevent oxidation of the weld.
mobile industrial robots A robotic device that performs industrial tasks related to the transportation of parts and material about the factory or warehouse. Mobile industrial robots have varying degrees of autonomy and can include tow vehicles, cart vehicles, fork-lift vehicles, and unit load carriers.
mobile robots A robot that is able to move through space. Mobile robots include wheeled robots, legged robots, and drones.
motor A machine that converts one form of energy, such as electricity, into another. Typically, an electric robot motor converts electrical energy into rotary motion.
NIOSH National Institute for Occupational Safety and Health. An organization responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH also provides robot safety guidelines.
nonvolatile chemical trail A deliberately placed path of a stable substance that will not evaporate. Nonvolatile chemical trails are used as paths for cart vehicles, or automated guided carts (AGCs).
Occupational Safety and Health Administration OSHA. A government agency dedicated to reducing injuries, illnesses, and deaths in the workplace. The Occupational Safety and Health Administration also provides robot safety guidelines.
offline programming A method of robot instruction where a programmer or computer engineer creates the instructions for a robotic operation independently of the robot. Offline programming involves either writing all the instructions for an operation or using a computer simulation.
online programming A method of creating instructions for a robot where the engineer interacts directly with an active robot during the process. Online programming includes teach-pendant programming and walk-through, or lead-through, programming.
operators A person responsible for running a manufacturing machine or process. Operators are responsible for running their assigned tasks correctly, safely, and efficiently, alerting engineers if problems or inefficiencies arise.
origin The fixed central point in the Cartesian coordinate system. The origin has a numerical value of zero at each axis.
packaging Applying a protective cover to materials, products, or parts. The consistency of packaging robots results in better and more efficient use of packaging materials, such as cling film and adhesive tape.
palletizing Placing, securing, and locating containers or objects on pallets. Palletizing robots may also pick up an object and place it in a compartmentalized container of multiple objects.
pallets A low, portable platform made of wood, metal, or plastic on which goods and materials are stacked for storage or transportation. Pallets can be transported by unit load carriers.
parallel robotic arms A robot that relies on computers and equations of motion to control the position and orientation of its end effector. Parallel robotic arms typically have six linear actuators that support the end effector from the base.
part-transfer The movement of parts from one location to another. Part-transfer robots, sometimes called pick-and-place robots, are fast and accurate, can operate in confined spaces, and often increase the rate of production processes.
payload The maximum amount of weight that a machine is able to manipulate. Payload limits vary robot to robot.
personal protective equipment PPE. Safety devices that technicians wear or use to prevent injury in the workplace. Personal protective equipment should be worn when entering the work envelope of a robot.
pick-and-place Applications that require robots to move parts from one location to another. Pick-and-place robots improve the precision, quality, and speed of manufacturing operations.
power systems The various components that provide and support robot motion. Power system components include motors, actuators, and joints.
presence-sensing mats A safety device that contains sensors to detect weight or pressure. When placed on the floor around hazardous areas, presence-sensing mats may be used to sense the presence of a human being or obstruction and either shut the machine down or prevent it from starting.
prismatic joints A joint that moves in a straight line across one axis. Prismatic joints, also called linear joints, are found in Cartesian robots.
processing Completing operations such as making transactions, manipulating data, triggering responses, and communicating with other digital systems. Robots used for processing applications can take over mundane informational tasks with great accuracy and precision.
production rates The number of parts that can be made in a set period of time. Production rates are generally increased through the use of robots, which can consistently perform tasks more quickly and with more accuracy than human operators.
programming The process of entering digital information into a computer or computerized system. Programming involves the use of a machine interface and a programming language that can tell the machine what actions to perform and allow the robot to interface with sensors.
programming The process of entering digital information into a computer or computerized system. Programming involves the use of a machine interface and a programming language that can tell the machine what actions to perform.
remote control A device used to direct the movements of a robot or other machine tool at a distance. Remote controls can be used in teach-pendant programming.
repeatability The ability to return to a specific position over and over again. High repeatability is a characteristic of a reliable robot.
resistance welding An electrical-resistance welding process where sheet metal parts are squeezed together between two electrodes and subjected to an electric current that heats and fuses the spot between the electrodes. Resistance welding, or spot welding, is often carried out by robots in manufacturing operations.
revolute joints A joint that rotates around a single axis. Revolute joints are found in robotic arms.
right-hand rule A quick reference that shows the location of the x, y, and z axes. A person displays his or her right hand and the first two fingers and thumb and, beginning with the thumb, each represents the x, y, and z axis in order.
rigid Stiff and inflexible. Parallel robotic arms are generally more rigid than serial robotic arms because all their links are secured at both ends.
robot A machine that automatically performs complicated and repetitive tasks. Robots often perform work that is too dangerous or strenuous for humans.
robotic arm An arm-shaped robot that is typically mounted on a base or placed on or suspended from a track. Robotic arms will typically have all revolute joints.
robotic arms An arm-shaped robot that is typically mounted on a base or placed on or suspended from a track. Robotic arms will typically have all revolute joints.
robot-processing automation The use of reprogrammable machines to complete operations such as making transactions, manipulating data, triggering responses, and communicating with other digital systems without human involvement. Robot-processing automation allows for the completion of mundane informational tasks with great precision and accuracy.
rotational axes An axis that defines circular movement. Rotational axes include the a, b, and c axes.
SCARA robots Selective Compliance Assembly Robot Arm robots. A type of cylindrical robot that has four axes of movement: x, y, z, and Theta Z. SCARA are often used for material handling applications.
Selective Compliance Assembly Robot Arm robots SCARA robots. A type of cylindrical robot that has four axes of movement: x, y, z, and Theta Z. Selective Compliance Assembly Robot Arm robots are often used for material handling applications.
sensors A device that detects a change in physical and environmental conditions. Sensors can detect the presence or absence of an object or person and stop or start robot operation as a result.
serial robotic arms A robot that is made up of a series of links connected by joints from the base to the end effector. Serial robotic arms generally have six degrees of freedom.
serialization The act of arranging in a set, numbered order. Parts serialization allows manufacturers to keep track of important information, such as when and where the parts were created.
shot blasting A surface conditioning process where small spheres of a hard material, usually steel, are forced through a nozzle using compressed air at the surface of a workpiece. Shot blasting, like grit blasting, is used to prepare the surface of a workpiece for another process, such as painting.
simulations A computer creation of a virtual space and activity. Simulations allow engineers to create control programs for a robot by maneuvering a computer-generated virtual version of that robot through a computer-generated virtual version of an operation.
simulators The computer program that generates the three-dimensional models of the robot, parts, and manufacturing environment. Simulators also record the desired robot movements, creating control programs that can be uploaded to the robot's machine interface.
speed The rate at which a whole robot or part of a robot travels. Faster speeds enable quicker robot motion but can often lead to less precision of movement.
spherical robots A robotic arm with an orb-shaped work envelope. Spherical robots can be configured in two ways: they may have two revolute joints and one prismatic joint or, in the case of a robotic arm, they may have three revolute joints.
spot welding An electrical-resistance welding process where sheet metal parts are squeezed together between two electrodes and subjected to an electric current that heats and fuses the spot between the electrodes. Spot welding, or resistance welding, is often carried out by robots in manufacturing operations.
stationary robots A robot that is anchored to the ground by a base. Stationary robots may have moving parts, but as a whole, they are fixed to a specific position.
surface finish The degree of smoothness of a part's surface after it has been manufactured. Surface finish is the result of the surface roughness, waviness, and flaws remaining on the part.
teach mode A robot setting where an engineer or operator is able to control the robot's movements and save those movements as an operating program. Teach mode, or manual mode, is used in online programming.
teach pendant A hand-held device that can be used to program a robot or control its movements. Teach pendants are used in teach-pendant programming.
teach pendant A hand-held device that can be used to program a robot or control its movements. Teach-pendant programs are one type of input device that allows engineers to communicate with a robot controller in order to control the robot.
teach-pendant programming A robot programming operation where engineers or operators take a robot through a process using a remote control or other machine interface. Teach-pendant programming is a type of online programming.
Theta Z coordinate An axis that corresponds to the angle around the z axis of the tool of a robot. The Theta Z coordinate is a rotating axis.
tool coordinate systems A positioning system where the origin is set at a fixed point on the end effector. In the tool coordinate system the Cartesian coordinates change orientation as the tool rotates on any of the a, b, or c axes.
torque The product of a radial, or tangential, force multiplied by the distance from the center of rotation. Torque is produced in electric motors through the introduction of electrical energy that is controlled by the drive.
tow vehicles A mobile robot that pulls trailers loaded with material. Tow vehicles, also known as tuggers or tugs, may be programmed to operate automatically or controlled by a remote operator.
track A mechanical device that allows a normally stationary robot to travel back and forth along a fixed length. Tracks give stationary robots the ability to work in a larger space than if they were fixed in one position.
tracking Keeping records of where and when parts are received and sent. Tracking is accomplished through the use of part serialization, which gives parts unique numbers by which they can be tracked.
tuggers A mobile robot that pulls trailers loaded with material. Tuggers, also known as tow vehicles or tugs, may be programmed to operate automatically or controlled by a remote operator.
tugs A mobile robot that pulls trailers loaded with material. Tugs, also known as tow vehicles or tuggers, may be programmed to operate automatically or controlled by a remote operator.
ultraviolet light UV light. Invisible light that can cause damage to the skin and eyes. Ultraviolet light is produced in arc welding operations, such as metal inert gas welding (MIG welding).
unit load carriers A programmable, highly sophisticated autonomous vehicle, often integrated with sensor technology, that transports pallets of material. Unit load carriers, or automated guided vehicles (AGVs), have a powered deck that can lift, lower, and sometimes rotate the pallet.
walk-through programming A programming method where operators physically take a robot through the steps of a manufacturing operation. Walk-through programming, also known as lead-through programming, is a type of online programming.
wear The erosion of material as a result of friction, chemical reaction, or other degrading processes. Machine-tending robots can examine tools for common forms of wear including flank, crater, and notch wear.
welding A joining process that uses either pressure or heat generated by friction, electricity, or the combustion of gases to permanently fuse two materials together. Production welding is often performed by robots.
wheeled robots A mobile robot whose movement depends on its wheels. Wheeled robots are commonly used in manufacturing.
work envelope The defined volume through which a robot can move. The work envelope includes the volume that encompasses the sweep and reach of the robot as well as the tool or workpiece that the end effector might be carrying.
workpiece A part that is being subjected to a variety of manufacturing processes. A workpiece may be subject to welding, forming, or other operations.
x axis The linear axis that represents side-to-side movement. The x axis, along with the y axis, is one of the horizontal axes in the Cartesian coordinate system.
y axis The linear axis that represents front-to-back movement. The y axis, along with the x axis, is one of the two horizontal axes in the Cartesian coordinate system.
z axis The linear axis that represents up-and-down movement. The z axis is the single vertical axis in the Cartesian coordinate system.