Month: May 2016

Pseudo-elasticity

Pseudo-elasticity

  Pseudo-elasticity          

        05/31/16

“Are there reversible responses to stress?”

If you have thought about this, then I recommend that you research about a most interesting effect known as Pseudo-elasticity. Pseudo-elasticity is an elastic (also known as reversible) response to applied stress. This effects is a result of the crystal lattice structure of materials.

Shape-memory alloy

Shape-memory alloy

Shape-memory alloy                 05/30/16

Are there materials that “remember” their shapes such as the ones seen on television?

Believe it or not, the answer to this question is yes! Shape-memory alloys are alloys that have the ability to “remember” their original shape (which means that they return to their original form after a deformation). This effect is a result of the material’s unique crystal structures, which allows it to reverse after a deformation. Shape-memory alloys have a wide domain of applications (tweezers used to remove foreign objects), ranging from medical appliances to military technology and even into clothing!!!

Linear actuator

Linear actuator

         Linear actuator  05/29/16

     “Is it possible to use a mechanical device to convert energy into linear motion?”

Like all machines that do not violate the laws of physics, the answer is yes. The name for this machine is called a linear actuator. Linear actuators converts energy into mechanical linear motion. All linear actuators require some form of energy to operate, weather it be pressure (such as in internal combustion engines) or electricity (such as in mechanical linear actuators). Linear actuators have applications to every form of life, weather it be in the automotive industry  or in mechatronic cleaning supplies.

Stepper motor

Stepper motor

     Stepper motor         05/28/16

  “Is it possible to have a motor that can make discrete revolutions?”

Like almost any engineering problem that does not violates the laws of physics, the answer is yes. A stepper motor is a motor whose revolutions are divided in to steps (hence the name stepper motor). Stepper motors are made up of an electromagnetic rotor and are surrounded by electrical windings. As each winding is activated with current, the rotor rotates to align itself with the stepper motor (as a result of being magnetized).

 

There are several different ways to control a stepper motor. The first one is known as a wave drive or a single-coil excitation.  As the name implies, each coil is activated one at a time, so the rotation is completely discrete. The next is known as a full drive in which two coils are active at a given time, with a “leapfrog” like pattern of coil activation (one the coil behind the leading one goes off, the coil in front goes on). A half step mode is like a full step except for the fact that there is a delay with each step, so at some time intervals there will be periods in which only one coil is activated. The most common method is called microstepping in which electric current is delivered sinusoidally to each coil so it becomes a continuous change instead of a discrete one.

 

There are three different types of builds for stepper motors. The Permanent magnet stepper motor uses a permanent magnet as the rotor which uses basic electromagnetism to guide each step. The variable reluctant stepper motor Used a non-magnetized soft iron rotor, and when each winding is activated the rotor rotates so that each of the teeth have a minimum gap between the ends of the magnet. The hybrid-synchronus stepper motor is a combination of the above two stepper motors, Which uses two teethed permanent magnet rotors of opposite polarity.

Ratchets

Ratchets

Ratchets           Isaac Gendler

        05/27/16

     “How can we have a rotary gear moves in only one direction?”

The answer to your question lies in a most peculiar device known as a ratchet. Contrary to popular belief, ratchets can be quite intelligent. Ratchets are very fundamental machines that can limit machine rotation to one direction. Rotors are composed of three parts. A gear whose teeth have been molded to fold out in only one direction. A Pawl that makes contact with the gear and stops the rotation when it goes in the incorrect direction. Finally, a mount serves as the platform connecting everything. The way that the Pawl halts the movement is as follows. Because the gears have been molded the “leading” side of the teeth is merged in to a curve with the top, and the “following” side is vertical. When the gear moves in the correct direction, the pawl will simply slide over the surface,while when the gear moves in the wrong direction, it will slam into the vertical surface, causing a stoppage. Ratchet mechanisms can be used in screwdriver items to ensure that rotation only happens in one direction. 

Servo

Servo

     Servo           05/26/16

How can we use a mechatronic machine to control motion?

If you have ever thought up the above question, then you should look into a servo. Servomechanisms are mechatronic devices that can be used to control desired feedback. This allows for more precise control of motion than a simple mechanical device. Servo’s are commonly used in hobby planes and radio controlled models, making servos a ubiquitous part of everyday life.  

Potentiometers

Potentiometers

  Potentiometer 05/25/16

Is it possible to have an adjustable resistor?

If you ask that question, then you have just thought up of Potentiometers.  A potentiometer is simply a variable resistor that can be controlled by the user. Potentiometers accomplish this by having three terminal resistors forming and a load that connect the potentiometer and the voltage source in one loop and the potentiometer and the load in another. Potentiometers have a wide range of uses, ranging from CD players to Servo mechanisms.