Mechatronics and Robotics MCQ Quiz - Objective Question with Answer for Mechatronics and Robotics - Download Free PDF

Explanation:

MEMS Foundries

Definition: MEMS (Micro-Electro-Mechanical Systems) foundries are specialized facilities where MEMS devices are fabricated. These devices combine electrical and mechanical components at a microscale, and they are used in a wide range of applications, from automotive sensors to medical devices.

Correct Option Analysis:

The correct option is:

Option 2: 1 and 3 only

This option correctly identifies two key aspects of MEMS foundries: the use of similar tools as IC (Integrated Circuit) fabrication and the typically three-dimensional nature of MEMS structures compared to the two-dimensional nature of ICs.

Explanation:

1. MEMS foundries use the same tools as IC fabrication:

MEMS foundries indeed utilize many of the same tools and techniques employed in the fabrication of integrated circuits. This includes photolithography, etching, deposition, and other processes that have been adapted from semiconductor manufacturing. The infrastructure and processes developed for IC fabrication are leveraged to produce the intricate and precise components required for MEMS devices. This commonality in tools is due to the similar scales at which both MEMS and ICs operate, often in the range of micrometers.

2. MEMS structures are typically 3D while ICs are 2D:

MEMS devices often require three-dimensional structures to perform their mechanical functions. For example, MEMS accelerometers and gyroscopes have moving parts that interact in three dimensions to sense motion and orientation. This three-dimensional complexity is a defining characteristic of MEMS technology. In contrast, ICs are generally planar, with components and interconnections laid out in two dimensions on the surface of the semiconductor wafer. While modern ICs may have multiple layers of circuitry, their fundamental design remains primarily two-dimensional.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: 1 and 2 only

This option includes the statement that MEMS production is simpler and faster than IC fabrication, which is not entirely accurate. While MEMS and ICs share some fabrication processes, MEMS production can be more complex due to the additional mechanical structures and the need for precise alignment and assembly of these components. The integration of mechanical and electrical elements often requires more intricate and varied processing steps, which can complicate and extend the production timeline.

Option 3: 2 and 3 only

This option combines the incorrect statement about the simplicity and speed of MEMS production with the correct observation about the three-dimensional nature of MEMS structures. As previously mentioned, MEMS production is not necessarily simpler or faster than IC fabrication. The additional mechanical components and the complexity of integrating these with electrical circuits can make MEMS fabrication more challenging.

Option 4: 1, 2, and 3

This option includes all three statements, one of which (the simplicity and speed of MEMS production) is incorrect. While it is true that MEMS foundries use similar tools as IC fabrication and that MEMS structures are typically three-dimensional, the assertion that MEMS production is simpler and faster is misleading and not universally applicable.

Conclusion:

Understanding the nuances of MEMS fabrication is crucial for accurately assessing the similarities and differences between MEMS and IC production. MEMS foundries utilize many of the same tools as IC fabrication, and MEMS devices often have three-dimensional structures, distinguishing them from the typically two-dimensional nature of ICs. However, MEMS production involves additional complexities due to the integration of mechanical and electrical components, making it not necessarily simpler or faster than IC fabrication.

Explanation:

MEMS Gyroscopes

Definition: MEMS (Micro-Electro-Mechanical Systems) gyroscopes are devices that measure angular velocity, the rate of rotation around a particular axis. They are widely used in various applications, including automotive systems, consumer electronics, and navigation systems. MEMS gyroscopes utilize micro-scale mechanical structures to sense and measure angular motion.

Working Principle: MEMS gyroscopes operate based on the principles of vibrating structures. Unlike traditional gyroscopes that use a rotating mass to detect angular velocity, MEMS gyroscopes rely on the Coriolis effect. The Coriolis effect causes a vibrating structure to experience a force when it undergoes rotational motion, which can be measured to determine the angular velocity.

Structure and Mechanism: The core component of a MEMS gyroscope is a vibrating structure, typically made of silicon, which is driven to oscillate at a specific frequency. When the device rotates, the Coriolis force acts on the vibrating structure, causing a change in its motion. This change is detected by capacitive, piezoelectric, or piezoresistive sensors, which convert the mechanical motion into an electrical signal proportional to the angular velocity.

Advantages:

• Compact size and lightweight, making them suitable for integration into portable and handheld devices.
• Low power consumption, which is essential for battery-powered applications.
• High sensitivity and accuracy in measuring angular velocity.
• Cost-effective production due to the use of standard semiconductor manufacturing processes.

Disadvantages:

• Susceptibility to external vibrations and shocks, which can affect accuracy.
• Temperature sensitivity, requiring compensation mechanisms for stable performance.

Applications: MEMS gyroscopes are widely used in various applications, including:

• Navigation Systems: MEMS gyroscopes are used in Inertial Measurement Units (IMUs) for navigation and control in vehicles, aircraft, and drones. They provide critical information for maintaining orientation and stability.
• Consumer Electronics: They are integrated into smartphones, gaming controllers, and wearable devices for motion sensing and user interface control.
• Automotive Systems: MEMS gyroscopes are used in vehicle stability control, rollover detection, and adaptive cruise control systems.
• Industrial Applications: They are used in robotics, machinery monitoring, and precision instrumentation for measuring angular velocity and orientation.

Correct Option Analysis:

The correct option is:

Option 2: 2 and 3 only

This option correctly identifies the key aspects of MEMS gyroscopes. They use vibrating structures (statement 2) and are commonly used in navigation systems (statement 3).

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: 1 and 2 only

This option is incorrect because statement 1 is not true for MEMS gyroscopes. Traditional gyroscopes use rotating mass to detect angular velocity, but MEMS gyroscopes use vibrating structures instead.

Option 3: 1 and 3 only

This option is incorrect as well because statement 1 is not valid for MEMS gyroscopes. While they are used in navigation systems (statement 3), they do not use rotating mass (statement 1).

Option 4: 1, 2, and 3

This option is incorrect because it includes statement 1, which is not true for MEMS gyroscopes. MEMS gyroscopes use vibrating structures, not rotating mass, to detect angular velocity.

Conclusion:

Understanding the working principles and applications of MEMS gyroscopes is essential for distinguishing them from traditional gyroscopes. MEMS gyroscopes utilize vibrating structures to measure angular velocity and are widely used in various applications, including navigation systems. This technology offers several advantages, such as compact size, low power consumption, and high sensitivity, making it suitable for modern electronic devices and systems.

Explanation:

Piezoelectric Materials in MEMS

Definition: Piezoelectric materials are substances that generate an electric charge in response to applied mechanical stress. This property is widely used in Micro-Electro-Mechanical Systems (MEMS) for sensors and actuators.

Working Principle: When mechanical stress is applied to a piezoelectric material, it creates an electrical charge proportional to the force exerted. Conversely, applying an electrical voltage to a piezoelectric material induces mechanical deformation. This bidirectional property makes piezoelectric materials highly valuable in MEMS technology.

Explanation of the Correct Option:

The correct answer is:

Option 2: 2 and 3 only

This option correctly identifies the statements that are accurate regarding piezoelectric materials in MEMS. Here's a detailed explanation:

Statement 1: "Silicon is an ideal piezoelectric material."

This statement is incorrect. Silicon, while being a fundamental material in the semiconductor industry and crucial for MEMS fabrication, does not exhibit piezoelectric properties. Silicon is used extensively for its mechanical properties and compatibility with microfabrication processes, but it does not generate an electric charge when mechanically stressed.

Statement 2: "PVDF and ZnO are common piezoelectric materials."

This statement is correct. Polyvinylidene fluoride (PVDF) and Zinc Oxide (ZnO) are well-known piezoelectric materials used in MEMS. PVDF is a polymer that exhibits significant piezoelectric properties and is flexible, making it suitable for various sensor applications. ZnO is a ceramic material with excellent piezoelectric characteristics, often used in thin-film form in MEMS devices for sensing and actuation.

Statement 3: "Piezoelectric materials can act as actuators."

This statement is correct. Piezoelectric materials are used as actuators in MEMS devices. When an electric voltage is applied to a piezoelectric material, it undergoes mechanical deformation. This property allows piezoelectric materials to be used as precision actuators in applications requiring fine movement control, such as in micro-positioning systems, ultrasonic transducers, and inkjet printers.

Advantages of Piezoelectric Materials in MEMS:

• High sensitivity to mechanical stress, making them excellent for sensor applications.
• Ability to produce precise mechanical movements under electrical control, essential for actuators.
• Fast response times, suitable for high-frequency applications.
• Compatibility with microfabrication techniques, allowing integration into MEMS devices.

Applications of Piezoelectric Materials in MEMS:

• Sensors: Used in accelerometers, pressure sensors, and acoustic sensors due to their sensitivity to mechanical changes.
• Actuators: Employed in micro-positioning devices, inkjet printer heads, and micro-pumps, where precise control of movement is required.
• Energy Harvesting: Convert mechanical vibrations into electrical energy, useful in powering small MEMS devices.

Additional Information:

To further understand the analysis, let’s evaluate the other options:

Option 1: 1 and 2 only

This option is incorrect because Statement 1 is not true. Silicon is not a piezoelectric material, so combining it with Statement 2, which is correct, does not make the option valid.

Option 3: 1 and 3 only

This option is incorrect because, while Statement 3 is correct, Statement 1 is not. The combination of these statements does not accurately reflect the true nature of piezoelectric materials in MEMS.

Option 4: 1, 2, and 3

This option is incorrect because, although Statements 2 and 3 are correct, Statement 1 is not. Including an incorrect statement invalidates the entire option.

Conclusion:

Understanding the properties and applications of piezoelectric materials is crucial in MEMS technology. While silicon is a cornerstone material in microfabrication, it does not exhibit piezoelectric properties. PVDF and ZnO, on the other hand, are common piezoelectric materials used for their sensitivity and actuation capabilities. Piezoelectric materials' ability to act both as sensors and actuators opens up a wide range of applications in MEMS, making them indispensable in the development of advanced microdevices.

Explanation:

MEMS Pressure Sensors

Definition: MEMS (Micro-Electro-Mechanical Systems) pressure sensors are devices that measure pressure using microfabrication technology. They integrate mechanical and electrical components at a microscopic scale to detect changes in pressure and convert these changes into an electrical signal.

Working Principle: The fundamental principle behind MEMS pressure sensors involves the deflection of a thin membrane or diaphragm. When pressure is applied, the membrane deforms, causing a change in resistance, capacitance, or frequency, depending on the sensor design. This change is then converted into an electrical signal that can be measured and processed.

Correct Option Analysis:

The correct option is:

Option 3: They use a piezoresistive membrane and can be used in catheter-tip sensors.

This option correctly identifies two key characteristics of MEMS pressure sensors. Firstly, many MEMS pressure sensors use a piezoresistive membrane. A piezoresistive material changes its electrical resistance when subjected to mechanical stress. In MEMS pressure sensors, this property is utilized to detect pressure changes. Secondly, MEMS pressure sensors are used in catheter-tip sensors. Catheter-tip sensors require small, precise, and sensitive pressure measurement capabilities, which MEMS technology provides.

Piezoresistive Membrane:

A piezoresistive membrane is a thin diaphragm made of a material whose electrical resistance changes when subjected to mechanical stress. Silicon is a common material used for this purpose due to its excellent piezoresistive properties. When pressure is applied to the membrane, it deforms, causing a change in resistance that can be measured by an electrical circuit. This change in resistance is proportional to the applied pressure, allowing for accurate pressure measurement.

Catheter-Tip Sensors:

Catheter-tip sensors are used in medical applications to measure pressure within the body, such as blood pressure in arteries or pressure in the heart chambers. These sensors need to be very small, precise, and biocompatible, making MEMS pressure sensors an ideal choice. The small size of MEMS sensors allows them to be integrated into the tip of a catheter without significantly increasing its diameter, enabling minimally invasive pressure measurements.

Additional Information:

To further understand the analysis, let’s evaluate the other options:

Option 1: They use a piezoresistive membrane.

This option is partially correct as it identifies the use of a piezoresistive membrane in MEMS pressure sensors. However, it does not address the use of MEMS pressure sensors in catheter-tip sensors, which is crucial for the complete understanding of their applications.

Option 2: They are typically reusable and costly.

This option is misleading. While some MEMS pressure sensors can be reusable, many are designed for single-use applications, especially in medical settings where sterility is essential. Additionally, MEMS pressure sensors are generally not considered costly. The microfabrication processes used to produce them can achieve high volumes at relatively low costs, making them affordable for various applications.

Option 4: They use a piezoresistive membrane, are typically reusable and costly, and can be used in catheter-tip sensors.

This option combines the correct information about the piezoresistive membrane and the use in catheter-tip sensors with the misleading information about being typically reusable and costly. Therefore, it is not entirely accurate.

Conclusion:

Understanding the characteristics and applications of MEMS pressure sensors is essential for selecting the correct sensor for a given application. MEMS pressure sensors with piezoresistive membranes offer precise and reliable pressure measurements, making them suitable for critical applications such as catheter-tip sensors in medical settings. Their small size, sensitivity, and ability to be mass-produced at low costs contribute to their widespread use in various industries.

Explanation:

MEMS Gyroscopes and Their Structures

Definition: Micro-Electro-Mechanical Systems (MEMS) gyroscopes are miniature devices that measure angular velocity or the rate of rotation around a particular axis. They are widely used in various applications, including smartphones, gaming controllers, automotive systems, and aerospace technology, for their small size, low power consumption, and high precision.

Working Principle: MEMS gyroscopes typically operate on the principle of Coriolis acceleration. When a system undergoes rotational motion, the Coriolis force acts on the moving parts within the gyroscope, causing a measurable displacement. This displacement is then converted into an electrical signal that represents the angular velocity.

Correct Option Analysis:

The correct option is:

Option 2: Vibrating structure

MEMS gyroscopes typically use a vibrating structure due to the difficulty in micromachining rotating parts. The vibrating structure gyroscopes are based on the principle of vibrating objects' tendency to retain their plane of vibration when the base rotates. The most common types of vibrating structure gyroscopes include tuning fork gyroscopes, vibrating ring gyroscopes, and vibrating wheel gyroscopes.

In a typical vibrating structure gyroscope, a proof mass is driven to vibrate at a certain frequency. When the gyroscope experiences angular motion, the Coriolis force causes a secondary vibration perpendicular to the original vibration. This secondary vibration is detected by capacitive, piezoelectric, or other sensing mechanisms, and the angular velocity is calculated.

Advantages of Vibrating Structure Gyroscopes:

• High precision and accuracy in measuring angular velocity.
• Compact size, making them suitable for integration into small devices.
• Low power consumption, which is essential for battery-operated devices.
• Robustness and reliability due to the absence of rotating parts, which are more susceptible to wear and tear.

Applications:

Vibrating structure gyroscopes are used in various applications, including:

• Consumer electronics, such as smartphones and tablets, for screen orientation and image stabilization.
• Automotive systems, for stability control and navigation.
• Aerospace, for navigation and control systems in aircraft and spacecraft.
• Gaming controllers and virtual reality devices, for motion sensing and control.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: Pendulum-based

Pendulum-based gyroscopes are not typically used in MEMS devices due to the challenges in miniaturizing pendulum structures. Pendulums are generally larger and more complex to integrate into small-scale MEMS technology.

Option 3: Magnetic field loop

Magnetic field loop gyroscopes, which utilize magnetic fields to measure angular velocity, are not commonly used in MEMS technology. The integration of magnetic field loops into MEMS devices is more complex and less practical compared to vibrating structures.

Option 4: Rotary gears

Rotary gears are mechanical components that involve rotating parts. The micromachining of such rotating parts at the MEMS scale is challenging due to issues related to friction, wear, and fabrication complexity. As a result, rotary gears are not typically used in MEMS gyroscopes.

Conclusion:

MEMS gyroscopes predominantly use vibrating structures due to their simplicity, precision, and reliability. The challenges associated with micromachining rotating parts make vibrating structures the preferred choice for these miniature devices. Understanding the principles and advantages of vibrating structure gyroscopes is essential for appreciating their widespread use in various modern technologies.

The correct answer is A third-generation high-level language.

• C is a high-level language.
  • C code is compiled by a compiler.
• In 1972, a great computer scientist Dennis Ritchie created a new programming language called 'C' at the Bell Laboratories.
• 'C' is a powerful programming language that is strongly associated with the UNIX operating system. Even most of the UNIX operating system is coded in 'C'.
• American National Standards Institute (ANSI) defined a commercial standard for 'C' language in 1989. Later, it was approved by the International Standards Organization (ISO) in 1990. 'C' programming language is also called 'ANSI C'.

Hint

• An assembly language is a low-level programming language designed for a specific type of processor. It may be produced by compiling source code from a high-level programming language (such as C/C++) but can also be written from scratch. 
• Compared to high-level languages like C or Java, assembly language is difficult to write. Example: To add numbers in assembly language ADD mnemonics are used but in high- level language + operator is used
• Machine language and assembly language are low-level languages.
• Machine code is a computer program written in machine language instructions that can be executed directly by a computer's central processing unit (CPU), hence machine language programs don’t require assembler .
• Machine code is a strictly numerical language which is intended to run as fast as possible, and may be regarded as the lowest-level representation of a compiled or assembled computer program or as a primitive and hardware-dependent programming language

The correct answer is Unique code for every character of every language.

• Unicode provides a unique number for every character.
  • It including punctuation marks, mathematical symbols, technical symbols, arrows, and characters making up non-Latin alphabets such as Thai, Chinese, or Arabic script.

Important Points

• Unicode is an industry-standard for the consistent encoding of written text.
• Unicode defines different character encodings, the most used ones being UTF-8, UTF-16, and UTF-32. UTF-8 is definitely the most popular encoding in the Unicode family, especially on the Web.

Additional Information

• ASCII (American Standard Code for Information Interchange) character set contains 128 characters for English letters, numbers, and some control characters.
  • ASCII encoding maps each character to 1 byte with the leading bit set to 0, and the other 7 bits representing the code point of the character.

The correct answer is Compiler.

• A compiler takes the program code (source code) and converts the source code to a machine language module (called an object file) at one go.
• An Interpreter  executes the source program statement by statement

Important Points

Explanation:

Initially, robots were programmed using textual languages such as Pascal and C. The code required to drive robots was very low-level, and very hard to create and maintain, requiring skills in both advanced programming and control theory. Textual robotic languages were developed specifically to address the problems associated with programming robots. These languages introduced “built-in” commands to operate the robot, eliminating (for instance) the need to develop code for motion primitives. 

VAL (Variable Assembly Language):

• The system software that controls the PUMA robot arm is called VAL, which is supplied by Unimation to be used with its controller called as MARK.
• The software is a sophisticated programming language and a complete robot control system but has disadvantages mostly due to the age of the product.
• VAL is stored in the controller computer memory. The controller also houses operating controls for the robot system.
• The VAL programming language consists of a full set of English language instructions for teaching and editing.
• Work programs are entered into the computer/controller using either of two different procedures or a combination of both.
• The programs can be entered with the teach pendant using the teach-by showing method or using the CRT and keyboard inputs.

Explanation:

PLC:

• A PLC (Programmable Logic Controller) also known as PLC is a specialized computer used to control machines and processes.

• PLC operates on digital signals.
• The PLC uses a programmable memory to store/ save instructions and specific functions that include ON/OFF control, counting, arithmetic, timing, sequencing, and also data handling.

The structure of a PLC:

Steps of PLC Operations:

• Input scan: In this, the state of all input devices that are connected to the PLC is detected.
• Program scan: This step executes the user-created program logic.
• Output scan: This step energizes or de-energizes all output devices that are connected to the PLC.
• Housekeeping: This step includes communications with programming terminals, internal diagnostics, etc.

Advantages of a PLC control system:

• It is flexible.
• It has a faster response time.
• It is easy to repair and expand the modular design.​

The correct answer is Beginner’s All-purpose Symbolic Instruction Code.

Important Points

• BASIC is one of the simplest and earliest high-level programming language supports in all operating systems.
• John G. Kemeny and Thomas E. Kurtz designed the original BASIC language DartmouthBasic in 1964.
  • The main moto is that all students should be able to use computers in every field.
• With the use of BASIC, people started developing custom software on their personnel computer for their business, profession, etc.

Additional Information

• QuickBasic (QB) is the compiler for the BASIC developed by Microsoft in 1985 which runs mainly on DOS.

Explanation

PLC: A PLC (Programmable Logic Controller) is an industrial computer control system that continuously monitors the state of input devices and makes decisions based upon a custom program to control the state of output devices.

Sequential Controller: A control system in which the individual steps are processed in a predetermined order, progression from one sequence step to the next being dependent on defined conditions being satisfied.

Microprocessor: A microprocessor is a multi-purpose, programmable clock-driven, register-based electronic device that reads binary instructions from a storage device called memory, accepts binary data as input, and processes data according to those instructions, and provide results as output.

The important point is- all the above three devices are electronic devices and don’t involve any mechanical action.

Automation, on other hand, is a technology that is mostly used to minimize human interaction (generally physical) with help of programming and computers. It involves the application of mechanical, electronics, and computer-based systems to control and operate the systems.

Concept:

Microcontroller:

A microcontroller is a VLSI IC that contains a processor (CPU) along with some other peripherals like memory (RAM and ROM), time/counter, communication interface, ADC, etc.

→ The difference between a microprocessor and a microcontroller is microprocessor is just a processor (CPU) and doesn’t have the above peripherals.

Feature of 8051 microcontroller:

1) It is an 8-bit microcontroller i.e. data bus is 8 bit wide.

2) It has 128 bytes of RAM which includes I / P and O / P registers.

3) ROM: It has 4 KB ROM

4) There are two 16-bit timers and counters in 8051 microcontroller: timer 0 and timer 1. 

Explanation:

To read the data from code memory 8051 microcontroller uses MOVC instructions.

MOV → Instruction used in data transfer between resister to resister or resister to memory.

2 byte, 1 machine cycle instruction.

MOV X:

Indirectly data transfer, 1 byte, 2 MCs

XCH:

Exchange accumulate with register

1 byte, 1 MCs

The correct answer is Compiler.

• A compiler takes the program code (source code) and converts the source code to a machine language module (called an object file).

Important Points

Additional Information

• Another specialized program, called a linker, combines this object file with other previously compiled object files (in particular run-time modules) to create an executable file.

Accumulator in 8051 microcontroller

• The Accumulator is a general-purpose register that is used to store the results of a large number of instructions.
• It can hold an 8-bit (1-byte) value and is the most versatile register the 8051 has due to the many numbers of instructions that make use of the accumulator.
• The accumulator is also identified as register A.
• Whenever any arithmetic operation is performed between two numbers, the resultant of that operation is stored in the accumulator.