A high performance positioning system (HPPS) is a type of
positioning system
A positioning system is a system for determining the position of an object in space. One of the most well-known and commonly used positioning systems is the Global Positioning System (GPS).
Positioning system technologies exist ranging from world ...
consisting of a piece of
electromechanics
In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...
equipment (e.g. an assembly of
linear stage
A linear stage or translation stage is a component of a precise motion system used to restrict an object to a single axis of motion. The term linear slide is often used interchangeably with "linear stage", though technically "linear slide" refe ...
s and
rotary stage
A rotary stage is a component of a motion system used to restrict an object to a single axis of rotation. The terms rotary table or rotation stage are often used interchangeably with rotary stage. All rotary stages consist of a platform and a bas ...
s) that is capable of moving an object in a
three-dimensional space
Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position (geometry), position of an element (i.e., Point (m ...
within a work envelope. Positioning could be done point to point or along a desired path of
motion
In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...
. Position is typically defined in
six degrees of freedom
Six degrees of freedom (6DOF) refers to the six mechanical degrees of freedom of movement of a rigid body in three-dimensional space. Specifically, the body is free to change position as forward/backward (surge), up/down (heave), left/right ...
, including linear, in an x,y,z
cartesian coordinate system
A Cartesian coordinate system (, ) in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in t ...
, and angular
orientation
Orientation may refer to:
Positioning in physical space
* Map orientation, the relationship between directions on a map and compass directions
* Orientation (housing), the position of a building with respect to the sun, a concept in building de ...
of yaw, pitch, roll. HPPS are used in many manufacturing processes to move an object (tool or part) smoothly and accurately in six degrees of freedom, along a desired path, at a desired orientation, with high
acceleration
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the ...
, high
deceleration
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the ...
, high
velocity
Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ...
and low
settling time
In control theory the settling time of a dynamical system such as an amplifier or other output device is the time elapsed from the application of an ideal instantaneous step input to the time at which the amplifier output has entered and remained ...
. It is designed to quickly stop its motion and accurately place the moving object at its desired final position and orientation with minimal jittering.
HPPS requires a structural characteristics of low moving mass and high stiffness. The resulting system characteristic is a high value for the lowest
natural frequency
Natural frequency, also known as eigenfrequency, is the frequency at which a system tends to oscillate in the absence of any driving force.
The motion pattern of a system oscillating at its natural frequency is called the normal mode (if all pa ...
of the system. High natural frequency allows the
motion controller
In video games and entertainment systems, a motion controller is a type of game controller that uses accelerometers or other sensors to track motion and provide input.
History
Motion controllers using accelerometers are used as controllers for ...
to drive the system at high
servo bandwidth Servo bandwidth is the maximum trackable sinusoidal frequency of amplitude A, with tracking achieved at or before 10% of A amplitude is reached. The servo bandwidth indicates the capability of the servo to follow rapid changes in the commanded inpu ...
, which means that the HPPS can reject all motion disturbing frequencies, which act at a lower frequency than the bandwidth. For higher frequency disturbances such as
floor vibration,
acoustic noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise ...
, motor cogging, bearing jitter and
cable carrier
Cable carriers, also known as drag chains, energy chains, or cable chains depending on the manufacturer, are guides designed to surround and guide flexible electrical cables and hydraulic or pneumatic hoses connected to moving automated machin ...
rattling, HPPS may employ structural
composite material
A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
s for
damping
Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples in ...
and
isolation mounts for
vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum ...
attenuation. Unlike articulating robots, which have
revolute joint
A revolute joint (also called pin joint or hinge joint) is a one- degree-of-freedom kinematic pair used frequently in mechanisms and machines. The joint constrains the motion of two bodies to pure rotation along a common axis. The joint does no ...
s that connect their links, HPPS links typically consists of sliding joints, which are relatively stiffer than revolute joints. That is the reason why high performance positioning systems are often referred to as
cartesian robot
A Cartesian coordinate robot (also called linear robot) is an industrial robot whose three principal axes of control are linear (i.e. they move in a straight line rather than rotate) and are at right angles to each other. The three sliding jo ...
s.
Performance
HPPS, driven by linear motors, can move at a combined high velocity on order of 3-5 m/s, high accelerations of 5-7 g, at
micron
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
or sub micron positioning accuracy with settling times on order of milliseconds and servo bandwidth of 30-50 Hz. Ball screw actuators, on the other hand, have typical bandwidth of 10-20 Hz and belt driven actuators at about 5-10 Hz. The bandwidth value of HPPS is about 1/3 of the lowest natural frequency in the range of 90-150 Hz. Settling time to +/- 1% Constant Velocity, or + / - 1 um jitter, after high acceleration or high deceleration respectively, takes an estimated 3 bandwidth periods. For example, a 50 Hz servo bandwidth, having a 1 / 50 · 1000 = 20 msec period, will settle to 1 um position accuracy within an estimated 3 · 20 = 60 msec. The lowest natural frequency equals the square root of system stiffness divided by moving inertia. A typical linear recirculating bearing rail, of a high performance positioning stage, has a stiffness on order of 100-300 N/um. Such a performance is required in
semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
process equipment, electronics
assembly lines
An assembly line is a manufacturing process (often called a ''progressive assembly'') in which parts (usually interchangeable parts) are added as the semi-finished assembly moves from workstation to workstation where the parts are added in sequ ...
, numerically controlled
machine tool
A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. All m ...
s,
coordinate-measuring machine
A coordinate measuring machine (CMM) is a device that measures the geometry of physical objects by sensing discrete points on the surface of the object with a probe. Various types of probes are used in CMMs, the most common being mechanical and l ...
s,
3D Printing
3D printing or additive manufacturing is the Manufacturing, construction of a three-dimensional object from a computer-aided design, CAD model or a digital 3D modeling, 3D model. It can be done in a variety of processes in which material is ...
,
pick-and-place machines,
drug discovery
In the fields of medicine, biotechnology and pharmacology, drug discovery is the process by which new candidate medications are discovered.
Historically, drugs were discovered by identifying the active ingredient from traditional remedies or by ...
assaying
An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a ...
and many more. At their highest performance HPPS may use
granite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...
base for thermal stability and flat surfaces,
air bearings
Air bearings (also known as aerostatic or aerodynamic bearings) are fluid bearings that use a thin film of pressurized gas to provide a low friction load-bearing interface between surfaces. The two surfaces do not touch, thus avoiding the tradit ...
for
jitter
In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a significa ...
free motion, brushless
linear motor
A linear motor is an electric motor that has had its stator and rotor "unrolled", thus, instead of producing a torque (rotation), it produces a linear force along its length. However, linear motors are not necessarily straight. Characteristicall ...
s for non contact, frictionless actuation, high force and low inertia, and laser interferometer for sub micron position feedback. On the other hand, a typical 6 degrees of freedom
articulated robot
An articulated robot is a robot with rotary joints (e.g. a legged robot or an industrial robot). Articulated robots can range from simple two-jointed structures to systems with 10 or more interacting joints and materials.
They are powered by a v ...
, with 1 m' reach, has a structural stiffness on the order of 1 N/um. That is why articulated robots are best being employed as automation equipment in processes which require position repeatability on the order of 100's microns, such as
robot welding
Robot welding is the use of mechanized programmable tools (robots), which completely automate a welding process by both performing the weld and handling the part. Processes such as gas metal arc welding, while often automated, are not necessaril ...
,
paint robot
Industrial paint robots have been used for decades in automotive paint applications.
Early paint robots were hydraulic versions, which are still in use today but are of inferior quality and safety to the latest electronic offerings. The newest ...
s,
palletizer
A palletizer or palletiser is a machine which provides automatic means for stacking cases of goods or products onto a pallet.
Manually placing boxes on pallets can be time consuming and expensive; it can also put unusual stress on workers. The f ...
s and many more.
History
The original HPPS were developed at Anorad Corporation (now
Rockwell Automation
Rockwell Automation, Inc. is an American provider of industrial automation whose brands include Allen-Bradley, FactoryTalk software and LifecycleIQ Services.
Headquartered in Milwaukee, Wisconsin, Rockwell Automation employs approximately 26,000 ...
) in the 1980s, after the invention of brushless
linear motor
A linear motor is an electric motor that has had its stator and rotor "unrolled", thus, instead of producing a torque (rotation), it produces a linear force along its length. However, linear motors are not necessarily straight. Characteristicall ...
s by Anorad's Founder and CEO,
Anwar Chitayat Anwar Chitayat (born August 21, 1927) is the founder and former CEO and chairman of Anorad Corp., which was acquired in 1998 by Rockwell Automation. Mr. Chitayat holds over 95 patents in Electronics, Semiconductors and Automation including Nanotech ...
. Initially HPPS were used for high precision manufacturing processes in semiconductor applications such as
Applied Materials
Applied Materials, Inc. is an American corporation that supplies equipment, services and software for the manufacture of semiconductor (integrated circuit) chips for electronics, flat panel displays for computers, smartphones, televisions, and ...
,
PCB
PCB may refer to:
Science and technology
* Polychlorinated biphenyl, an organic chlorine compound, now recognized as an environmental toxin and classified as a persistent organic pollutant
* Printed circuit board, a board used in electronics
* ...
Inspection
Orbotech
Orbotech Ltd. a subsidiary of KLA Corporation and a technology company used in the manufacturing of consumer and industrial products throughout the electronics and adjacent industries. The company providing electronics reading, writing, and conn ...
and High Velocity Machine Tool
Ford
Ford commonly refers to:
* Ford Motor Company, an automobile manufacturer founded by Henry Ford
* Ford (crossing), a shallow crossing on a river
Ford may also refer to:
Ford Motor Company
* Henry Ford, founder of the Ford Motor Company
* Ford F ...
. In parallel linear motor technology and their integration in HPPS, was expanded around the world. As a result, in 1996
Siemens
Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad.
The principal divisions of the corporation are ''Industry'', '' ...
integrated its CNC with Anorad linear motors to drive a 20 m' long Maskant machine at
Boeing
The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...
for
chemical milling
Chemical milling or industrial etching is the subtractive manufacturing process of using baths of temperature-regulated etching chemicals to remove material to create an object with the desired shape. Other names for chemical etching inclu ...
of
aircraft wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is express ...
s. In 1997
FANUC
FANUC ( or ; often styled Fanuc) is a Japanese group of companies that provide automation products and services such as robotics and computer numerical control wireless systems. These companies are principally of Japan, Fanuc America Corpor ...
licensed Anorad's linear motor technology and integrated it as a complete solution with their CNC products line. And in 1998, Rockwell Automation acquired Anorad to compete with Siemens and Fanuc in providing a complete linear motor solutions to drive high velocity machine tools in Automotive
transfer lines. Today linear motors are being used in hundreds of thousands high performance positioning systems, which drive manufacturing processes around the world. Their market is expected to grow, according to some studies, at 4.4% a year and reach $1.5B in 2025.
System requirements
Applications
* Semiconductors -
Photolithography
In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer, to protect ...
is a
wafer (electronics)
In electronics, a wafer (also called a slice or substrate) is a thin slice of semiconductor, such as a crystalline silicon
Crystalline silicon or (c-Si) Is the crystalline forms of silicon, either polycrystalline silicon (poly-Si, consisting o ...
manufacturing process in
semiconductor fabrication plant
In the microelectronics industry, a semiconductor fabrication plant (commonly called a fab; sometimes foundry) is a factory where devices such as integrated circuits are manufactured.
Fabs require many expensive devices to function. Estimates ...
s. It uses linear motor stages or maglev stages, for extreme positioning, to move its wafer stage.
* Electronics -
Surface-mount technology
Surface-mount technology (SMT), originally called planar mounting, is a method in which the electrical components are mounted directly onto the surface of a printed circuit board (PCB). An electrical component mounted in this manner is referred ...
is using high performance, linear motor, positioning systems to mount
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
chips on
printed circuit board
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a L ...
s.
* Optics -
Stereo microscopes use linear motor positioning stages for high smoothness of motion during scanning
* Machine Tools - Wire
electrical discharge machining
Electrical discharge machining (EDM), also known as spark machining, spark eroding, die sinking, wire burning or wire erosion, is a metal
fabrication process whereby a desired shape is obtained by using electrical discharges (sparks). Material i ...
is used for cutting thick hard metals such as in
Die (manufacturing)
A die is a specialized machine tool used in manufacturing industries to cut and/or form material to a desired shape or profile. Stamping dies are used with a press, as opposed to drawing dies (used in the manufacture of wire) and casting dies ( ...
. Linear motor / air bearing positioning systems provide high smoothness of motion.
* CMM -
Coordinate-measuring machine
A coordinate measuring machine (CMM) is a device that measures the geometry of physical objects by sensing discrete points on the surface of the object with a probe. Various types of probes are used in CMMs, the most common being mechanical and l ...
often require granite base, isolation mounts, linear motor actuators, air bearing and laser interferometer.
* Lab Automation -
High-throughput screening
High-throughput screening (HTS) is a method for scientific experimentation especially used in drug discovery and relevant to the fields of biology, materials science and chemistry. Using robotics, data processing/control software, liquid handlin ...
process is used in
laboratory automation
Laboratory automation is a multi-disciplinary strategy to research, develop, optimize and capitalize on technologies in the laboratory that enable new and improved processes. Laboratory automation professionals are academic, commercial and gover ...
for
drug discovery
In the fields of medicine, biotechnology and pharmacology, drug discovery is the process by which new candidate medications are discovered.
Historically, drugs were discovered by identifying the active ingredient from traditional remedies or by ...
, where linear motor positioning provides high acceleration / deceleration with short settling time.
Specifications
System
specification (technical standard)
A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard.
There are different types of technical or engineering specificati ...
is an official interface between the application requirements (problem), as described by the user (customer) and the design (solution) as optimized by the developer (supplier).
*
Inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...
- Indicates the resistance of the moving load (tool or part) to linear (kg) and angular (kg·m2) change in velocity. To maximize natural frequency the inertia of the moving load should be minimal.
* Size - Indicates the geometrical constraints of the system's width (m), length(m) and height (m), as may be needed for handling, transport as installation.
*
Motion
In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...
- Indicates process cycle time (s) and process constraints for each
degree of freedom
Degrees of freedom (often abbreviated df or DOF) refers to the number of independent variables or parameters of a thermodynamic system. In various scientific fields, the word "freedom" is used to describe the limits to which physical movement or ...
, including maximum travel (m, rad), maximum velocity (m/s, rad/s) and maximum acceleration/deceleration (m/s2, rad/s2).
* Precision - Indicates linear and
angular resolution
Angular resolution describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution. ...
of position measurement and motion (um, urad) as well as
total indicator reading In metrology and the fields that it serves (such as manufacturing, machining, and engineering), total indicator reading (TIR), also known by the newer name full indicator movement (FIM), is the difference between the maximum and minimum measurements ...
of
accuracy and precision
Accuracy and precision are two measures of ''observational error''.
''Accuracy'' is how close a given set of measurements ( observations or readings) are to their ''true value'', while ''precision'' is how close the measurements are to each oth ...
for each degree of freedom.
*
Jitter
In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a significa ...
- Indicates maximum amplitude (um) of high frequency vibrations which is allowed at stand still conditions.
* Constant velocity - Indicates the required smoothness of motion and allowed variations in (+/- %) of required constant velocity (m/s, rad/s) during motion.
*
Stiffness
Stiffness is the extent to which an object resists deformation in response to an applied force.
The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is.
Calculations
The stiffness, k, of a b ...
- Indicates the resistance of position change in response to external load (N/um, N·m/rad).
* Life - indicates the expected time (hrs) or travel (km) the most active degree of freedom of the system is expected to act reliably in process operation.
* Reliability -
Mean time between failures
Mean time between failures (MTBF) is the predicted elapsed time between inherent failures of a mechanical or electronic system during normal system operation. MTBF can be calculated as the arithmetic mean (average) time between failures of a system ...
(hrs, cycles) often associated with a requirement for a
Failure modes, effects, and diagnostic analysis Failure modes, effects, and diagnostic analysis (FMEDA) is a systematic analysis technique to obtain subsystem / product level failure rates, failure modes and diagnostic capability. The FMEDA technique considers:
* All components of a design,
* The ...
* Maintainability -
Mean time to repair
Mean time to repair (MTTR) is a basic measure of the maintainability of repairable items. It represents the average time required to repair a failed component or device. Expressed mathematically, it is the total corrective maintenance time for ...
(hrs), often associated with system manuals including, operation, maintenance schedule and spare parts list.
* Environment - Indicates the expected disturbance conditions that the system may encounter during operation within its life time including Thermal, Humidity, Shock and Vibration, Cleanliness and Radiation.
Environment
* Thermal - Indicates the highest and lowest
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.
Thermometers are calibrated in various temperature scales that historically have relied o ...
(°C) that the system may endure during operation. Effects structural deformations and precision. May require cooling, insulation and low thermal conductivity material.
*
Humidity
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present.
Humidity depe ...
- Indicated the level of water vapors in the surrounding air (%). May include the required system protection based on
IP Code
The IP code or ingress protection code indicates how well a device is protected against water and dust. It defined by the International Electrotechnical Commission (IEC) under the international standard IEC 60529 which classifies and pro ...
. May require protective seals.
*
Shock (mechanics)
A mechanical or physical shock is a sudden acceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation.
Shock describes matter subject to extreme rates of force with respect to ti ...
and Vibration - Indicates the level of
floor vibration and other process disturbances. May require active or passive vibration isolation mounts and structural material with high damping.
*
Cleanliness
Cleanliness is both the state of being clean and free from germs, dirt, trash, or waste, and the habit of achieving and maintaining that state. Cleanliness is often achieved through cleaning. Culturally, cleanliness is usually a good quality, as ...
- Indicates the allowable level (size and quantity per unit volume) of particles in the surrounding air. May require
cleanroom
A cleanroom or clean room is an engineered space, which maintains a very low concentration of airborne particulates. It is well isolated, well-controlled from contamination, and actively cleansed. Such rooms are commonly needed for scientif ...
operation, filtration of incoming air and protective seals.
* Radiation -
Electromagnetic interference
Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electros ...
may require shielded cable management, non ferrous structural material and protective shields of the linear motor magnet plates.
System solution
Configuration
HPPS configuration is typically optimized for maximum structural stiffness with maximum damping and minimum inertia, smallest
Abbe error
Abbe error, named after Ernst Abbe, also called sine error, describes the magnification of angular error over distance. For example, when one measures a point that is 1 meter away at 45 degrees, an angular error of 1 degree corresponds to a positi ...
at the point of interest (POI), with minimum components and maximum maintainability.
* X - A single
linear stage
A linear stage or translation stage is a component of a precise motion system used to restrict an object to a single axis of motion. The term linear slide is often used interchangeably with "linear stage", though technically "linear slide" refe ...
, driven by
linear motor
A linear motor is an electric motor that has had its stator and rotor "unrolled", thus, instead of producing a torque (rotation), it produces a linear force along its length. However, linear motors are not necessarily straight. Characteristicall ...
,
ball screw
A ball screw (or ballscrew) is a mechanical linear actuator that translates rotational motion to linear motion with little friction. A threaded shaft provides a helical raceway for ball bearings which act as a precision screw. As well as bein ...
or
timing belt, is typically available as a standard actuator (aka slide, axis or table) from many suppliers.
* XYZ - A customized assembly of single stages, including moving
cable management
Cable management refers to management of electrical or optical cable in a cabinet or an installation. The term is used for products, workmanship or planning.
Cables can easily become tangled, making them difficult to work with, sometimes res ...
. Z axis is typically actuated with a ball screw or linear motor with a
counterbalance
A counterweight is a weight that, by applying an opposite force, provides balance and stability of a mechanical system. The purpose of a counterweight is to make lifting the load faster and more efficient, which saves energy and causes less wear ...
. Axes may be separated to reduce inertia.
* XYZR - Rotational axes including pitch, yaw and roll are typically added in HPPS for orienting the end of arm tool (EOAT) or
Robot end effector
In robotics, an end effector is the device at the end of a robotic arm, designed to interact with the environment. The exact nature of this device depends on the application of the robot.
In the strict definition, which originates from serial ro ...
.
* Gantry - Gantry configuration provides maximum work envelope in XYZ configuration per given size constraints. It has 2 parallel axes for x, controlled as a single axis or master / slave. Ideal for
transfer lines.
* Rotary (pitch, yaw, roll) -
Rotary stage
A rotary stage is a component of a motion system used to restrict an object to a single axis of rotation. The terms rotary table or rotation stage are often used interchangeably with rotary stage. All rotary stages consist of a platform and a bas ...
s may be customized with
linear stage
A linear stage or translation stage is a component of a precise motion system used to restrict an object to a single axis of motion. The term linear slide is often used interchangeably with "linear stage", though technically "linear slide" refe ...
at various order to best meet the specifications. They are typically using
direct-drive mechanism
A direct-drive mechanism is a mechanism design where the force or torque from a prime mover is transmitted directly to the effector device (such as the drive wheels of a vehicle) without involving any intermediate couplings such as a gear train or ...
, analogous to linear motors.
* Custom - Custom configurations of HPPS may be required in the
mathematical optimization
Mathematical optimization (alternatively spelled ''optimisation'') or mathematical programming is the selection of a best element, with regard to some criterion, from some set of available alternatives. It is generally divided into two subfi ...
process of integrating the best system components into the most compact, and responsive system.
System analysis
System analysis is a process of understanding the relationships between design parameters, operating conditions, environmental variables and system performance based on
system modeling
Systems modeling or system modeling is the interdisciplinary study of the use of models to conceptualize and construct systems in business and IT development.[Dynamics (mechanics)
Dynamics is the branch of classical mechanics that is concerned with the study of forces and their effects on motion. Isaac Newton was the first to formulate the fundamental physical laws that govern dynamics in classical non-relativistic phys ...](_blan ...<br></span></div> and analysis tools
* <div class=)
- Optimizing
linear motion
Linear motion, also called rectilinear motion, is one-dimensional motion along a straight line, and can therefore be described mathematically using only one spatial dimension. The linear motion can be of two types: uniform linear motion, with co ...
and
rotation
Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...
al profiles, dynamic accuracy, bearing loads, and motor power, using analysis tools such as
MATLAB
MATLAB (an abbreviation of "MATrix LABoratory") is a proprietary multi-paradigm programming language and numeric computing environment developed by MathWorks. MATLAB allows matrix manipulations, plotting of functions and data, implementation ...
,
Simulink
Simulink is a MATLAB-based graphical programming environment for modeling, simulating and analyzing multidomain dynamical systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers t ...
,
Mathcad,
Microsoft Excel
Microsoft Excel is a spreadsheet developed by Microsoft for Microsoft Windows, Windows, macOS, Android (operating system), Android and iOS. It features calculation or computation capabilities, graphing tools, pivot tables, and a macro (comp ...
*
Vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum ...
analysis - Estimating
natural frequency
Natural frequency, also known as eigenfrequency, is the frequency at which a system tends to oscillate in the absence of any driving force.
The motion pattern of a system oscillating at its natural frequency is called the normal mode (if all pa ...
,
servo bandwidth Servo bandwidth is the maximum trackable sinusoidal frequency of amplitude A, with tracking achieved at or before 10% of A amplitude is reached. The servo bandwidth indicates the capability of the servo to follow rapid changes in the commanded inpu ...
, settling times, using analysis tools such as
MATLAB
MATLAB (an abbreviation of "MATrix LABoratory") is a proprietary multi-paradigm programming language and numeric computing environment developed by MathWorks. MATLAB allows matrix manipulations, plotting of functions and data, implementation ...
,
Simulink
Simulink is a MATLAB-based graphical programming environment for modeling, simulating and analyzing multidomain dynamical systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers t ...
,
Mathcad,
Microsoft Excel
Microsoft Excel is a spreadsheet developed by Microsoft for Microsoft Windows, Windows, macOS, Android (operating system), Android and iOS. It features calculation or computation capabilities, graphing tools, pivot tables, and a macro (comp ...
*
Accuracy and precision
Accuracy and precision are two measures of ''observational error''.
''Accuracy'' is how close a given set of measurements ( observations or readings) are to their ''true value'', while ''precision'' is how close the measurements are to each oth ...
- Estimating 3D static errors at the point of interest as a function of axes straightness, flatness, pitch, yaw, roll, wobble and ran-outs using analysis tools such as
Mathcad,
Microsoft Excel
Microsoft Excel is a spreadsheet developed by Microsoft for Microsoft Windows, Windows, macOS, Android (operating system), Android and iOS. It features calculation or computation capabilities, graphing tools, pivot tables, and a macro (comp ...
*
Strength of materials
The field of strength of materials, also called mechanics of materials, typically refers to various methods of calculating the stresses and strains in structural members, such as beams, columns, and shafts. The methods employed to predict the re ...
- Estimating stiffness of axes, frames, supports and mounting structures, using
Finite element method
The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat ...
tools such as
AutoCAD
AutoCAD is a commercial computer-aided design (CAD) and drafting software application. Developed and marketed by Autodesk, AutoCAD was first released in December 1982 as a desktop app running on microcomputers with internal graphics controllers. ...
,
Nastran
NASTRAN is a finite element analysis (FEA) program that was originally developed for NASA in the late 1960s under United States government funding for the aerospace industry. The MacNeal-Schwendler Corporation (MSC) was one of the principal and o ...
*
Thermal expansion
Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.
Temperature is a monotonic function of the average molecular kinetic ...
- Predicting thermal expansions and optimizing
heat transfer
Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, ...
using insulation and cooling, using analysis tools such as
AutoCAD
AutoCAD is a commercial computer-aided design (CAD) and drafting software application. Developed and marketed by Autodesk, AutoCAD was first released in December 1982 as a desktop app running on microcomputers with internal graphics controllers. ...
,
Nastran
NASTRAN is a finite element analysis (FEA) program that was originally developed for NASA in the late 1960s under United States government funding for the aerospace industry. The MacNeal-Schwendler Corporation (MSC) was one of the principal and o ...
*
Fluid dynamics
In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids— liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) an ...
- Estimating flow rates and supply pressures for fluid
actuator
An actuator is a component of a machine that is responsible for moving and controlling a mechanism or system, for example by opening a valve. In simple terms, it is a "mover".
An actuator requires a control device (controlled by control signal) a ...
s and cooling using analysis tools such as
Computational fluid dynamics
Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid flows. Computers are used to perform the calculations required to simulate th ...
*
Servo control
Servo control is a method of controlling many types of RC/hobbyist servos by sending the servo a PWM (pulse-width modulation) signal, a series of repeating pulses of variable width where either the width of the pulse (most common modern hobby ser ...
- Estimating required filters and tuning parameters for
PID controller
A proportional–integral–derivative controller (PID controller or three-term controller) is a control loop mechanism employing feedback that is widely used in industrial control systems and a variety of other applications requiring continuou ...
loops of system axes using analysis tools such as
MATLAB
MATLAB (an abbreviation of "MATrix LABoratory") is a proprietary multi-paradigm programming language and numeric computing environment developed by MathWorks. MATLAB allows matrix manipulations, plotting of functions and data, implementation ...
,
Simulink
Simulink is a MATLAB-based graphical programming environment for modeling, simulating and analyzing multidomain dynamical systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers t ...
*
Reliability engineering
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specifie ...
- Estimating system
mean time between failures
Mean time between failures (MTBF) is the predicted elapsed time between inherent failures of a mechanical or electronic system during normal system operation. MTBF can be calculated as the arithmetic mean (average) time between failures of a system ...
using analysis tools such as
Mathcad,
Microsoft Excel
Microsoft Excel is a spreadsheet developed by Microsoft for Microsoft Windows, Windows, macOS, Android (operating system), Android and iOS. It features calculation or computation capabilities, graphing tools, pivot tables, and a macro (comp ...
Component sizing
Component sizing is the process of selecting standard parts from component suppliers, or designing a custom part for manufacturing
* Frame - Typically made of aluminum or steel weldments of hollow tubes, possibly filled in with concrete composite for damping. Mounted on leveling pads and secured to floor possibly with earthquake posts.
*
Actuator
An actuator is a component of a machine that is responsible for moving and controlling a mechanism or system, for example by opening a valve. In simple terms, it is a "mover".
An actuator requires a control device (controlled by control signal) a ...
** slide, base - High precision bases use granite for flatness and thermal stability. Lower precision standard stages use extruded aluminum. Custom stages typically use ribbed aluminum or stainless steel machined for low inertia high stiffness.
** bearing - Options include cross roller bearing for relatively short travel, recirculating bearing for higher stiffness longer travel and
air bearing with
granite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...
base for high smoothness of motion, higher precision.
**
servo motor
A servomotor (or servo motor) is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also r ...
- Typically linear
brushless DC electric motor
A brushless DC electric motor (BLDC motor or BL motor), also known as an electronically commutated motor (ECM or EC motor) or synchronous DC motor, is a synchronous motor using a direct current (DC) electric power supply. It uses an electronic ...
for horizontal axes with 3 phase synchronized current in moving coil and field in stationary, low cogging, magnet plates. For vertical linear motor axes a counterbalance may be used. Rotary stages use similar 2 parts, direct drive motor, including a stationary coil armature and a moving magnetic rotor.
** feedback - Typically high resolution encoder, optical, magnetic or captative, analog or digital, linear or rotary, absolute or
Incremental encoder
An incremental encoder is a linear or rotary electromechanical device that has two output signals, ''A'' and ''B'', which issue pulses when the device is moved. Together, the ''A'' and ''B'' signals indicate both the occurrence of and direction ...
with index mark for homing. Laser
interferometry
Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...
for long travel, sub-micron precision.
** forcer - Forcer options include
ball screw
A ball screw (or ballscrew) is a mechanical linear actuator that translates rotational motion to linear motion with little friction. A threaded shaft provides a helical raceway for ball bearings which act as a precision screw. As well as bein ...
for high force,
rack and pinion
A rack and pinion is a type of linear actuator that comprises a circular gear (the '' pinion'') engaging a linear gear (the ''rack''). Together, they convert rotational motion into linear motion. Rotating the pinion causes the rack to be driven ...
for long travel and
timing belt drive for high velocity. Their limitations in HPPS is friction, jitter, backlash, lower stiffness and maintenance.
* cable management - For power and signal transmission. The weakest link of the system reliability chain. Lower bend radius for low profile increases fatigue. Requires cable carrier or using flat ribbon cable. Introduce jitter.
* Accessories - Hard stops, stiffening brackets, bellows,
shock mount
A shock mount or isolation mount is a mechanical fastener that connects two parts elastically. They are used for shock and vibration isolation.
Isolation mounts allow a piece of equipment to be securely mounted to a foundation and/or frame and, a ...
s,
air cooling
Air cooling is a method of dissipating heat. It works by expanding the surface area or increasing the flow of air over the object to be cooled, or both. An example of the former is to add cooling fins to the surface of the object, either by maki ...
fans, limits, flexures,
robot end effector
In robotics, an end effector is the device at the end of a robotic arm, designed to interact with the environment. The exact nature of this device depends on the application of the robot.
In the strict definition, which originates from serial ro ...
grippers,
machine vision
Machine vision (MV) is the technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry. Machine vision refers to m ...
camera and sensors for
Artificial Intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech re ...
,
Machine learning
Machine learning (ML) is a field of inquiry devoted to understanding and building methods that 'learn', that is, methods that leverage data to improve performance on some set of tasks. It is seen as a part of artificial intelligence.
Machine ...
, monitoring such as
accelerometer
An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is accele ...
s, temperature sensors and
gyroscope
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rota ...
s.
*
servo drive
A servo drive is an electronic amplifier used to power electric servomechanisms.
A servo drive monitors the feedback signal from the servomechanism and continually adjusts for deviation from expected behavior.
Function
A servo drive receives a c ...
- Amplifying motion control signals to drive servo motors. Ranging from low power to 10s KW. For example, 40 KW in driving high force linear motor of 10,000 N moving at 4 m/s. DC voltage ranges from a safe 24V/48V to over 400 V. High current loop update rates, of motor signals, are on order of thousands of Hz. Popular network communication with motion controller is via
EtherCAT
EtherCAT (Ethernet for Control Automation Technology) is an Ethernet-based fieldbus system invented bBeckhoff Automation The protocol is standardized in IEC 61158 and is suitable for both hard and soft real-time computing requirements in automati ...
.
* Motion
PID controller
A proportional–integral–derivative controller (PID controller or three-term controller) is a control loop mechanism employing feedback that is widely used in industrial control systems and a variety of other applications requiring continuou ...
- Options include computer
numerical control
Numerical control (also computer numerical control, and commonly called CNC) is the automated control of machining tools (such as drills, lathes, mills, grinders, routers and 3D printers) by means of a computer. A CNC machine processes a pi ...
(CNC), single axis, multi axis, PC based, stand alone or integrated with servo drive and /or PLC, including I/O, auto tuning, diagnostic and programming available from multiple sources.
*
Programmable logic controller
A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity tha ...
(PLC) - Higher layer in the
hierarchical control system A hierarchical control system (HCS) is a form of control system in which a set of devices and governing software is arranged in a hierarchical tree. When the links in the tree are implemented by a computer network, then that hierarchical control sy ...
for process sequence control, provided by many suppliers.
System testing
System testing is an iterative process of system development, intended to validate system analysis modeling, proof of concepts, safety factor of performance specifications and acceptant testing.
* Motion travel, maximum velocity, maximum acceleration, jerk - Commonly provided within the motion controller.
* Linear accuracy, repeatability, flatness, straightness, yaw, pitch - Laser
interferometer
Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber op ...
.
* Angular accuracy, repeatability, runout, wobble -
Autocollimator
An autocollimator is an optical instrument for non-contact measurement of angles. They are typically used to align components and measure deflections in optical or mechanical systems. An autocollimator works by projecting an image onto a target mir ...
.
* Cycle time, settling time, jitter, constant velocity - Commonly provided within the motion controller.
* Thermal stability - Temperature sensors mounted at multiple location to observe heat transfer.
* Inertia, stiffness - scales, dial indicators and
force gauge
A force gauge (also called a force meter) is a measuring instrument used to measure forces. Applications exist in research and development, laboratory, quality, production and field environment. There are two kinds of force gauges today: mechanica ...
.
*
Natural frequency
Natural frequency, also known as eigenfrequency, is the frequency at which a system tends to oscillate in the absence of any driving force.
The motion pattern of a system oscillating at its natural frequency is called the normal mode (if all pa ...
,
servo bandwidth Servo bandwidth is the maximum trackable sinusoidal frequency of amplitude A, with tracking achieved at or before 10% of A amplitude is reached. The servo bandwidth indicates the capability of the servo to follow rapid changes in the commanded inpu ...
- Commonly provided with motion controller which has
frequency response
In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of sy ...
tools.
*
Mean time between failure
Mean time between failures (MTBF) is the predicted elapsed time between inherent failures of a mechanical or electronic system during normal system operation. MTBF can be calculated as the arithmetic mean (average) time between failures of a syste ...
, Life test - Non stop operation for specified period without a failure in extreme operating conditions under continuous monitoring with frequent visual and sensor checking.
References
Further reading
* {{cite book , last= Slocum, first= Alexander, date= 1992, title= Precision Machine Design, url= https://b-ok.org/book/3391718/c38cee#:~:text=Alexander%20H.%20Slocum%20This%20book%20is%20a%20comprehensive,component%20and%20system%20design%20considerations%20for%20precision%20machines., publisher=Society of Manufacturing , page=750 , isbn=0872634922
Positioning instruments
Motion control
Electric motors
Electromechanical engineering
Systems engineering