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ME302: Mechatronics

Unit 3: Actuators   Motion is the basic activity within a mechatronic system, whereby a mechanical system is being controlled by the use of actuators under a supervising control system. Position, speed, or both, are usually the controlled variables in a mechatronic system. The following are examples of mechatronic systems in which speed, position, or both, are monitored and controlled: the speed of a conveyor belt has to be closely controlled in order to ensure that items spend exactly the correct time in a process; the position of a robotic arm manipulator has to be very accurately controlled in order to successfully achieve a delicate task (e.g., surgery); and in an elevator system, both speed and position have to be accurately controlled.

In order to achieve motion, actuators are needed. An actuator is a device that can produce force in order to achieve linear acceleration in translational systems, or that can produce torque in order to achieve rotational acceleration in rotational systems.

Thus, it is important to be aware of the different types of actuators that can be used in mechatronic systems to bring about motion. This unit will introduce you to the different types of actuators and will provide you with guidance on the advantages and disadvantages of each actuator to enable you to select the correct one for a given application.

Unit 3 Time Advisory
This unit should take approximately 49.5 hours to complete.

☐    Subunit 3.1: 2.5 hours

☐    Subunit 3.2: 3.5 hours

☐    Subunit 3.3: 0.75 hours

☐    Subunit 3.4: 39.5 hours

☐    Sub-subunit 3.4.1: 10 hours

☐    Sub-subunit 3.4.2: 12.25 hours

☐    Sub-subunit 3.4.3: 0.25 hours

☐    Sub-subunit 3.4.4: 3.75 hours

☐    Sub-subunit 3.4.5: 12.75 hours

☐    Sub-subunit 3.4.6: 0.5 hours

☐    Subunit 3.5: 0.5 hours

☐    Subunit 3.6: 2.25 hours

☐    Subunit 3.7: 0.5 hours

Unit3 Learning Outcomes
Upon successful completion of this unit, the student will be able to:
- Identify and describe the different types of actuators used in mechatronic systems. - Explain the principle of operation of induction motors, dc motors, stepper motors, and servomotors. - Select the correct type of actuator for an application. - Size an actuator for an application.

3.1 Introduction to Actuators   Actuators are important in mechatronic systems as they bring about motion. They can be translational or rotational. Electrical motors are the most widely used type of actuator in mechatronic systems. Electric motors are electromagnetic actuators that convert electrical energy into mechanical energy. All electric motors provide mechanical energy in a rotational form (torque and rotational speed). An actuator can be thought of as a device that converts electrical energy into mechanical energy.

A lead screw is a device that converts rotational motion into translational motion. Pulleys, sheaves, or sprockets are devices that can convert rotational motion into translational motion and vice versa. A gear box can change the speed and torque of rotational motion and is thus a device that matches the motor to the load. More information about gearboxes will be given in the last subunit of this unit.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif’s “Revision of Mechanics Basics” Link: University of Jordan: Dr. Lutfi Al-Sharif’s “Revision of Mechanics Basics” (PDF)

    Instructions: Please click on the link above to download the PDF, and read pages 1 to 8 of the document, which presents an overall review of translational and rotational mechanics basic. You will read the remainder of the document in subunit 3.7.

    Reading this chapter should take approximately 1 hour and 30 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select the link titled “Voice Coil Head Actuator and 3-Phase Stepper Spindle Motor in a Computer Hard-Drive” to download the video. View the brief demonstration, which shows an example of the use of actuators in a hard drive. As you watch the video, notice that there are two actuators: a motor that rotates the hard disk and another actuator that moves the reading head.

    You will recall that in Unit 1, a number of possible mechatronic systems were discussed as follows: mechanical (translational), mechanical (rotational), fluidic (pneumatic), fluidic (hydraulic), and thermal.

    Intuitively, the term actuator is immediately linked to mechanical actuators (whether rotational or translational). However, it is important to note that actuators could also be fluidic (hydraulic or pneumatic) and thermal (e.g., heater).

    Watching this video and pausing to take notes should take less than 10 minutes.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select the “Hydraulic Gear Pumps” link to download the video. View the brief demonstration for an example of a hydraulic amplifier (similar to an electrical amplifier) that uses a pilot valve as the input. Notice that this pump is of the positive displacement type; a positive displacement pump moves known volumes of fluid with every rotation.

    Watching this video and pausing to take notes should take approximately 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the section titled “Actuators,” and select the link titled “Hydraulic Pilot Valve Amplifier Cut-Away” to download the video. View the brief demonstration for an example of pneumatic actuators.

    Watching this video and pausing to take notes should take less than 10 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select on the link titled “Pneumatic Cylinders of Various Types and Sizes” to download the video. Another type of actuator is the permanent magnet linear actuator, also referred to as a solenoid. Watch this video for a demonstration of its construction.

    Watching this video and pausing to take notes should take less than 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: YouTube: Jeri Ellsworth’s “Solenoid Basics Part 1” Link: YouTube: Jeri Ellsworth’s “Solenoid Basics Part 1” (YouTube)

    Instructions: Please click on the link above and view the entire video. This video shows you an example of a linear actuator. It is electromagnetically operated.

    Watching this video and pausing to take notes should take approximately 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.2 Analogy between Electrical Circuits and Magnetic Circuits   The videos that you watched in the previous subunit have introduced you to different types of actuators (hydraulic, pneumatic, and electromagnetic). Some were rotational and others were translational (linear). We now will move on to have a detailed look at the different types of actuators. Before introducing the four types of motors, some basic electromagnetic principles are reviewed below. You will need to revise the following basic principles in preparation for the rest of this unit.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif ‘s “Analogy between Electrical Circuits and Magnetic Circuits” Link: University of Jordan: Dr. Lutfi Al-Sharif ‘s “Analogy between Electrical Circuits and Magnetic Circuits” (PDF)

    Instructions: Please click on the link above and read this article to study the analogy between electrical circuits and magnetic circuits.

    Reading this chapter should take approximately 1 hour and 30 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.

  • Reading: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Electromechanics” Link: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Electromechanics” (PDF)

    Instructions: Please click on the link above and then select the link titled “Electromechanics” to download the PDF. Note that all the links are arranged alphabetically. Read pages 25 to 38. This resource will provide you with a deep understanding of magnetic fundamentals and magnetic circuits. Magnetic circuits are fundamental to the operation of most actuators (e.g., electric motor and solenoids).

    Reading this chapter should take approximately 2 hours.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.3 Motor and Generator Principles   This subunit introduces some basic concepts necessary for understanding DC motor operation.

  • Web Media: YouTube: David Colarusso’s “What Is the Magnetic Field?” Link: YouTube: David Colarusso’s “What Is the Magnetic Field?” (YouTube)

    Instructions: Please click on the link above and watch this video, which revises the concept of a magnetic field.

    Watching this video and pausing to take notes should take approximately 10 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: YouTube: Yves Pelletier’s “Direct Current Electric Motor” Link: YouTube: Yves Pelletier’s “Direct Current Electric Motor” (YouTube)

    Instructions: Please click on the link above and view the brief video, which discusses the principle operation of the DC motor.

    Watching this video should take less than 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: YouTube: Fizzics.org’s “Fleming’s Left Hand Rule” Link: YouTube: Fizzics.org’s “Fleming’s Left Hand Rule” (YouTube)

    Instructions: Please click on the link above and view the brief video, which discusses Fleming’s left hand rule. Fleming’s left hand rule is used in order to determine the direction of force imposed on a current carrying conductor subjected to a magnetic field.

    Watching this video and pausing to take notes should take approximately 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: YouTube: Yves Pelletier’s “Electric Generator” Link: YouTube: Yves Pelletier’s “Electric Generator” (YouTube)

    Instructions: Please click on the link above and view the brief video, which introduces the principle of operation of a DC generator.

    Watching this video should take approximately 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: YouTube: David Colarusso’s “How to Build a Simple Motor” Link: YouTube: David Colarusso’s “How to Build a Simple Motor” (YouTube)

    Instructions: Please click on the link above and view the brief video, which further illustrates the principle of operation of the DC motor.

    Watching this video and pausing to take notes should take approximately 10 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.4 Types of Actuators   This subunit will concentrate on the electromagnetic actuators used in mechatronic systems.

3.4.1 General Introduction to Motors   - Reading: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Motors for Mechatronics – An Introduction” Link: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Motors for Mechatronics – An Introduction” (PDF)

 Instructions: Please click on the link above and then select the
link titled “Motors for Mechatronics – An Introduction” to download
the PDF. Note that the names of the links are ordered
alphabetically. Read this document (80 pages), which gives a general
introduction on motors used in mechatronic systems.  

 Reading this document should take approximately 10 hours.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

3.4.2 Brushed DC Motors   DC motors have traditionally been used as they offer high starting torque and good speed control. DC motors are usually of the brushed type; they have brushes that allow connecting the supply to the rotating armature. Recently, brushless DC motors have become available, whereby the switching function is achieved using solid state electronics. Brushes and commutators require continuous maintenance and can be a source of unreliability for DC motors.

  • Reading: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Brushed DC Motors” Link: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Brushed DC Motors” (PDF)

    Instructions: Please click on the link above and then select the link titled “Brushed DC Motors” to download the PDF. Note that the links are ordered alphabetically. Be careful not to select “Brushed DC Motors, PWM, H-Bridge, Optical Encoder, Arduino System” as this also begins with brushed DC motors. Read this presentation (104 pages) by Kevin Craig about brushed DC motors.

    Reading this presentation should take approximately 8 hours.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif’s “Introduction to DC Motors” Link: University of Jordan: Dr. Lutfi Al-Sharif’s “Introduction to DC Motors” (PDF)

    Instructions: Please click on the link above and read this chapter (30 pages). This text presents you with a detailed description of the construction and operation of the DC motor. When reading this document, concentrate on the following items: the principle of operation of the DC motor, the concept of wave winding in arranging the conductors inside a DC motor, methods of connecting the field of the DC motor, the concept of armature reaction, methods of overcoming the problem of armature reaction, and the basic model of the DC motor.

    Reading this chapter should take approximately 4 hours.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and click on the link for the title “DC Motor Components” to download the video. View the brief demonstration, which illustrates the different components of a DC motor.

    Watching this video and pausing to take notes should take approximately 10 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.4.3 Brushless DC Motors   This sub-subunit examines the brushless type of DC motor. One of the main disadvantages of brushed DC motors is the maintenance requirements that are necessary for the brushes and commutators. A brushless DC motor uses Hall Effect sensors to switch the current within the armature without the need for mechanical brushes and commutators. This improves the reliability of motor and reduces the maintenance requirements.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the section titled “Actuators,” and select the link titled “Brushless DC Motor from a Computer Fan” to download the video. Watch the video for a demonstration of a brushless DC motor and its method of operation.

    Watching this video and pausing to take notes should take less than 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select the link for the title “Brushless DC Motor Gear Pump” to download the video. View the brief demonstration, which shows a brushless DC motor used to drive a gear pump.

    Watching this video and pausing to take notes should take less than 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.4.4 AC Induction Motor   The squirrel cage induction motor (referred to as SCIM for short) is the workhorse of the modern industry. It is used in 90% of industrial applications. The reason it is widely used is because of its robustness and reliability. It is effectively maintenance free. The main problem with the AC induction motors is that it has been difficult to vary their speed until power electronics has been applied in the design of variable speed drives that can vary the speed of the AC induction motors.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif’s “Introduction to AC Induction Motors” Link: University of Jordan: Dr. Lutfi Al-Sharif’s “Introduction to AC Induction Motors” (PDF)

    Instructions: Please click on the link above to access the PDF, and read this article (16 pages). When reading the following document, pay special attention to the following items: the principle of a rotating constant magnitude magnetic field; how the intersection of the rotating magnetic field with the squirrel cage rotor; how to calculate the speed of rotation of the motor; and the concept of synchronous speed, asynchronous speed, and slip.

    From this article, you will notice that a constant magnitude rotating magnetic field is produced by shifting three vectors of magnetic fields by 120 degrees in space (arrangement of the coils in a motor) and 120 degrees in time (three phase power supply).

    Reading this article should take approximately 3 hours.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select the link titled “AC Induction Motor (Single Phase)” to download the video. View the brief demonstration, which shows the construction of a single phase squirrel cage induction motor. Notice how the bars in the rotor are skewed in order to reduce vibration or pulsation in the torque.

    Watching this video and pausing to take notes should take less than 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: YouTube: Gotchacam’s “Assembly of AC Induction Motors” Link: YouTube: Gotchacam’s “Assembly of AC Induction Motors” (YouTube)

    Instructions: Please click on the link above and watch this video. This video shows the construction of a three phase AC squirrel cage induction motor. Note the different stages of building the motor, starting with the stator and then the rotor. Also, note how special attention is paid to the balancing of the rotor to avoid vibration at full speed.

    Watching this video and pausing to take notes should take approximately 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: YouTube: Gotchacam’s “Assembly of AC Induction Motors” Link: YouTube: Gotchacam’s “Assembly of AC Induction Motors” (YouTube)

    Instructions: Please click on the link above and watch this video. This video shows the construction of a three phase AC squirrel cage induction motor. Note the different stages of building the motor, starting with the stator and then the rotor. Also, note how special attention is paid to the balancing of the rotor to avoid vibration at full speed.

    Watching this video and pausing to take notes should take approximately 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.4.5 Stepper Motors   As opposed to the DC motors and the AC induction motors, stepper motors move in specified steps. They are effectively digital motors. For these reasons, they are ideal for accurate positioning applications. However, they are generally limited to low power applications.

  • Reading: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Step Motors” Link: Rensselear Polytechnic Institute and Marquette University: Kevin Craig’s Multidisciplinary Mechatronic Innovations: “Step Motors” (PDF)

    Instructions: Please click on the link above and then select the link titled “Step Motors.” Note that the names of the links are ordered alphabetically. Read the material from Kevin Craig about stepper motors (125 pages). Concentrate on the following points when reading the material: pages 10 and 11 show the advantages and disadvantages of stepper motors; and pages 46 through 48 explain the concepts of full stepping, half stepping, and micro-stepping.

    Reading this chapter should take approximately 12 hours and 30 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select the link titled “Stepper Motor Step Response and Acceleration through Resonance” to download the video. View the brief demonstration, which shows the stepped response and movement of stepper motors.

    Watching this video and pausing to take notes should take approximately 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select the link titled “DC and Stepper Motor Examples” to download the video. View this brief demonstration, which shows real life examples of stepper motors and DC motors.

    Watching this video and pausing to take notes should take less than 10 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.4.6 Servo-Motors   A servo-motor is a DC motor that has been fitted with position feedback and a close loop control system. This makes a servo-motor ideal for use in accurate positioning application such as robotic arms. Similar to the stepper motor, it is limited to small power applications.

  • Web Media: YouTube: Bartek Sliwinski’s “How Do Servos Work?” Link: YouTube: Bartek Sliwinski’s “How Do Servos Work?” (YouTube)

    Instructions: Please click on the link above and watch the video, which shows the construction of a servo-motor. From watching the video, you will notice the following: a servo motor is basically a DC motor with a closed loop control system; the angular position of the rotor is monitored using a potentiometer; a control circuit is used to compare the required angular position with the actual angular position of the rotor; the control circuit then moves the motor in order to eliminate the difference between the actual angular position and the required angular position; and the required position is communicated to the motor via a pulse that has a time duration corresponding to the required angle.

    Watching this video and pausing to take notes should take approximately 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll down to the “Actuators” section, and select the link titled “Radio Control (RC) Servo Motor with Pulse-Width-Modulation Control” to download the video. View the brief demonstration, which clearly illustrates the aforementioned point about how the required angle is achieved.

    Watching this video and pausing to take notes should take less than 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” Link: Colorado State University’s “Video Demonstrations of Mechatronic Devices and Principles” (Windows Media Player)

    Instructions: Please click on the link above, scroll to the “Actuators” section, and select the link titled “Servo Motor System” to download the video. Watch the brief demonstration, which shows the use of two servo motors fitted with feedback devices and controllers.

    Watching this video and pausing to take notes should take less than 5 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5 Criteria for Actuator Selection   A critical part of the mechatronics system design process is the selection of a suitable actuator. There are a number of important factors that must be taken into consideration when selecting a suitable actuator.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif’s “Actuator Selection” Link: University of Jordan: Dr. Lutfi Al-Sharif’s “Actuator Selection” (PDF)

    Instructions: Please click on the link above to download the PDF. Study the brief document, which presents the various factors that must be taken into consideration when selecting an actuator. The reading also presents a comparison between the various types of motors.

    Reading this document should take approximately 30 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.

3.6 Sizing of Actuators   When sizing a motor, the most important parameter that needs to be calculated is the torque. This is usually referred to as the rated torque. Once the rated torque has been calculated based on the application, the necessary motor can be selected from the datasheet. The following two problems illustrate the data needed to calculate the required torque. The first problem is that of selecting an AC induction motor for an elevator.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif’s “Sizing of an AC Induction Motor for an Elevator System” Link: University of Jordan: Dr. Lutfi Al-Sharif’s “Sizing of an AC Induction Motor for an Elevator System” (PDF)

    Instructions: Please click on the link above and read this chapter (9 pages).

    Reading this chapter should take approximately 1 hour and 30 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif’s “The Sizing of a Permanent Magnet DC Motor for an Electric Vehicle” Link: University of Jordan: Dr. Lutfi Al-Sharif’s “The Sizing of a Permanent Magnet DC Motor for an Electric Vehicle” (PDF)

    Instructions: Please click on the link above to access the PDF, and read this document (4 pages), which attempts to select a suitable motor. In the second problem, the document provides the necessary information for the sizing of a DC motor for an electric vehicle.

    Reading this document should take approximately 45 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.

3.7 Use of Gearboxes to Match Speed and Torque   Gearboxes are extremely important in mechanical and mechatronic systems. A gearbox is a device that can change both speed and torque. It can be used to match the actuator output with the mechanical system under control.

In many cases, the actuator speed (e.g., motor) is too high for the application, and the torque it produces is too low. Using a gearbox reduces the rotational speed and increases the rotational torque. Under ideal conditions, the input power is equal to the output power. Under such ideal conditions, the product of the input rotational speed and the input torque is equal to the product of the output rotational speed and the output torque. In reality, the output power will be less than the input power, and the ratio of the output power to the input power is the efficiency of the gearbox.

In most applications, gearboxes are used as step down devices, as they reduce the speed and increase the torque.

  • Reading: University of Jordan: Dr. Lutfi Al-Sharif’s “Revision of Mechanics Basics” Link: University of Jordan: Dr. Lutfi Al-Sharif’s “Revision of Mechanics Basics” (PDF)

    Instructions: Please click on the link above to access the PDF. Read pages 9 to 11, which provides more detail about the use of gearboxes in mechatronic systems.

    Reading this document should take approximately 30 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 license. It is attributed to Dr. Lutfi Al-Sharif and the original can be found here.