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Inchworm Motor
The inchworm motor is a device that uses piezoelectric actuators to move a shaft with nanometer precision. In its simplest form, the inchworm motor uses three piezo-actuators (2 and 3, see Figure 1.) mounted inside a tube (1) and electrified in sequence to grip a shaft (4) which is then moved in a linear direction. Motion of the shaft is due to the extension of the lateral piezo (2) pushing on two clutching piezos (3). Operation The actuation process of the inchworm motor is a six step cyclical process after the initial relaxation and initialization phase. Initially, all three piezos are relaxed and unextended. To initialize the inchworm motor the clutching piezo closest to the direction of desired motion (which then becomes the forward clutch piezo) is electrified first then the six step cycle begins as follows (see Figure 2.): Step 1. Extension of the lateral piezo. Step 2. Extension of the aft clutch piezo. Step 3. Relaxation of the forward clutch piezo. Step 4. Relaxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezoelectric
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied Stress (mechanics), mechanical stress. The word ''piezoelectricity'' means electricity resulting from pressure and latent heat. It is derived from the Greek language, Greek word ; ''piezein'', which means to squeeze or press, and ''ēlektron'', which means amber, an ancient source of electric charge. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no Centrosymmetry, inversion symmetry. The piezoelectric effect is a reversible process (thermodynamics), reversible process: List of piezoelectric materials, materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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) and a source of energy. The control signal is relatively low energy and may be electric voltage or current, pneumatic, or hydraulic fluid pressure, or even human power. Its main energy source may be an electric current, hydraulic pressure, or pneumatic pressure. The Control device is usually a valve. When it receives a control signal, an actuator responds by converting the source's energy into mechanical motion. In the ''electric'', ''hydraulic'', and ''pneumatic'' sense, it is a form of automation or automatic control. History The history of the pneumatic actuation system and the hydraulic actuation system dates to around the time of World War II (1938). It was first created by Xhiter Anckeleman who used his knowledge of engines and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanometer
330px, Different lengths as in respect to the molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re, -er, American spelling) is a units of measurement, unit of length in the International System of Units (SI), equal to one billionth (short scale) of a metre () and to 1000 picometres. One nanometre can be expressed in scientific notation as , and as metres. History The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short – since it is of a micron (micrometre), and was often denoted by the symbol mμ or (more rarely and confusingly, since it logically should refer to a ''millionth'' of a micron) as μμ. Etymology The name combines the SI prefix ''nano-'' (from the Ancient Greek , ', "dwarf") with the parent unit name ''metre'' (from Greek , ', "unit of measurement"). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 other. In other words, ''precision'' is a description of '' random errors'', a measure of statistical variability. ''Accuracy'' has two definitions: # More commonly, it is a description of only '' systematic errors'', a measure of statistical bias of a given measure of central tendency; low accuracy causes a difference between a result and a true value; ISO calls this ''trueness''. # Alternatively, ISO defines accuracy as describing a combination of both types of observational error (random and systematic), so high accuracy requires both high precision and high trueness. In the first, more common definition of "accuracy" above, the concept is independent of "precision", so a particular set of data can be said to be accurate, precise, both, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezo Inchworm Motor A
Piezo is derived from the Greek πιέζω, which means to squeeze or press, and may refer to: * PIEZO1, a mechanosensitive ion protein * Piezoelectric pickups for guitars and other musical instruments * Piezoelectric sensor, a device that converts differences in physical force to generate voltage * Piezoelectric speaker, a type of small loudspeaker * Piezoelectricity, electrical charge built up in response to mechanical stress * Piezometer, a device that measures the pressure of groundwater at a certain point * Piezoresistive effect, a change in the electrical resistance of a material in response to mechanical stress * Piezorina, a genus of South American bird * Micro Piezo, a print head technology developed by Epson * Piezo ignition Piezo ignition is a type of ignition that is used in portable camping stoves, gas grills and some lighters. Piezo ignition uses the principle of piezoelectricity, which, in short, is the electric charge that accumulates in some materials in resp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezomotor Type Inchworm
A piezoelectric motor or piezo motor is a type of electric motor based on the change in shape of a piezoelectric material when an electric field is applied, as a consequence of the converse piezoelectric effect. An electrical circuit makes acoustic or ultrasonic vibrations in the piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials, which can produce linear or rotary motion depending on their mechanism. Examples of types piezoelectric motors include inchworm motors, stepper and slip-stick motors as well as ultrasonic motors which can further be further categorized into standing wave and travelling wave motors. Piezoelectric motors typically use a cyclic stepping motion, which allows the oscillation of the crystals to produce an arbitrarily large motion, as opposed to most other piezoelectric actuators where the range of motion is limited by the static strain that may be induced in the piezoelectric element ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inchworm Motor
The inchworm motor is a device that uses piezoelectric actuators to move a shaft with nanometer precision. In its simplest form, the inchworm motor uses three piezo-actuators (2 and 3, see Figure 1.) mounted inside a tube (1) and electrified in sequence to grip a shaft (4) which is then moved in a linear direction. Motion of the shaft is due to the extension of the lateral piezo (2) pushing on two clutching piezos (3). Operation The actuation process of the inchworm motor is a six step cyclical process after the initial relaxation and initialization phase. Initially, all three piezos are relaxed and unextended. To initialize the inchworm motor the clutching piezo closest to the direction of desired motion (which then becomes the forward clutch piezo) is electrified first then the six step cycle begins as follows (see Figure 2.): Step 1. Extension of the lateral piezo. Step 2. Extension of the aft clutch piezo. Step 3. Relaxation of the forward clutch piezo. Step 4. Relaxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Tunneling Microscope
A scanning tunneling microscope (STM) is a type of microscope used for imaging surfaces at the atomic level. Its development in 1981 earned its inventors, Gerd Binnig and Heinrich Rohrer, then at IBM Zürich, the Nobel Prize in Physics in 1986. STM senses the surface by using an extremely sharp conducting tip that can distinguish features smaller than 0.1 nm with a 0.01 nm (10 pm) depth resolution. This means that individual atoms can routinely be imaged and manipulated. Most microscopes are built for use in ultra-high vacuum at temperatures approaching zero kelvin, but variants exist for studies in air, water and other environments, and for temperatures over 1000 °C. STM is based on the concept of quantum tunneling. When the tip is brought very near to the surface to be examined, a bias voltage applied between the two allows electrons to tunnel through the vacuum separating them. The resulting ''tunneling current'' is a function of the tip position, applied ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feedback
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems: History Self-regulating mechanisms have existed since antiquity, and the idea of feedback had started to enter economic theory in Britain by the 18th century, but it was not at that time recognized as a universal abstraction and so did not have a name. The first ever known artificial feedback device was a float valve, for maintaining water at a constant level, invented in 270 BC in Alexandria, Egypt. This device illustrated the principle of feedback: a low water level opens the valve, the rising water then provides feedback into the system, closing the valve when the required level is reached. This then reoccurs in a circular fashion as the water level fluctuates. Centrifugal governors were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patch Clamp
The patch clamp technique is a laboratory technique in electrophysiology used to study ionic currents in individual isolated living cells, tissue sections, or patches of cell membrane. The technique is especially useful in the study of excitable cells such as neurons, cardiomyocytes, muscle fibers, and pancreatic beta cells, and can also be applied to the study of bacterial ion channels in specially prepared giant spheroplasts. Patch clamping can be performed using the voltage clamp technique. In this case, the voltage across the cell membrane is controlled by the experimenter and the resulting currents are recorded. Alternatively, the current clamp technique can be used. In this case, the current passing across the membrane is controlled by the experimenter and the resulting changes in voltage are recorded, generally in the form of action potentials. Erwin Neher and Bert Sakmann developed the patch clamp in the late 1970s and early 1980s. This discovery made it possible to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micromanipulator
A micromanipulator is a device which is used to physically interact with a sample under a microscope, where a level of precision of movement is necessary that cannot be achieved by the unaided human hand. It may typically consist of an input joystick, a mechanism for reducing the range of movement and an output section with the means of holding a microtool to hold, inject, cut or otherwise manipulate the object as required. The mechanism for reducing the movement usually requires the movement to be free of backlash. This is achieved by the use of kinematic constraints to allow each part of the mechanism to move only in one or more chosen degrees of freedom, which achieves a high precision and repeatability of movement, usually at the expense of some absolute accuracy. Movement Movement reduction can be performed by mechanical levers, hydraulically using pistons of different diameters connected by tubing containing non-compressible fluid, electronically using stepper motors or lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unimorph
A unimorph or monomorph is a cantilever that consists of one active layer and one inactive layer.http://robotics.eecs.berkeley.edu/~ronf/PAPERS/icra01b.pdf In the case where active layer is piezoelectric, deformation in that layer may be induced by the application of an electric field. This deformation induces a bending displacement in the cantilever. The inactive layer may be fabricated from a non-piezoelectric material. See also *Bimorph A bimorph is a cantilever used for actuation or sensing which consists of two active layers. It can also have a passive layer between the two active layers. In contrast, a piezoelectric unimorph has only one active (i.e. piezoelectric) layer and o ... References Piezoelectric materials {{Material-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
