Introduction to CPS Hardware Platforms and Layers

A Cyber-Physical System (CPS) hardware platform is described as the physical embodiment of integrating computation with physical processes. Using the self-driving car analogy, which mapping best captures how the three CPS layers interact to sense, decide, and act in the physical world?

• Sensors perceive the environment; the computing unit processes data and makes decisions; actuators execute those decisions to affect the physical world.

• Actuators collect data; sensors execute decisions; the computing unit transmits outputs to the physical world.

• The computing unit senses the road; actuators process the data; sensors cause changes in the physical world.

• Sensors and actuators both make decisions; the computing unit only holds the components together.

A CPS platform is broken into three core layers. If you are designing the information flow for a CPS, which correct directional flow aligns with the roles given for each layer?

• Actuation Layer → Sensing Layer → Computation & Communication Layer

• Sensing Layer (input from physical to cyber) → Computation & Communication Layer (cyber brain and nervous system) → Actuation Layer (output from cyber to physical)

• Computation & Communication Layer → Actuation Layer → Sensing Layer

• Sensing Layer → Actuation Layer → Computation & Communication Layer

A city plans a CPS-based streetlight system that should turn lights on at dusk without human intervention. Which sensor and reasoning best fits the requirement?

• Thermistor, because dusk correlates with lower ambient temperature

• Photoresistor (LDR), because light intensity decreases at dusk causing resistance change the controller can detect

• Ultrasonic sensor, because it can measure the distance to approaching vehicles at dusk

• Accelerometer, because the pole’s vibration increases when night winds start

A hospital’s medical CPS records blood oxygen from a pulse oximeter, but the readings are noisy. Which signal-conditioning sequence most appropriately prepares the data for the computer to process?

• Amplify the signal, then convert it from digital to analog

• Low-pass filter to remove high-frequency noise, amplify if needed, then perform analog-to-digital conversion (ADC) to create discrete values

• Increase sensor range to capture higher maximum values, then compress to digital

• Raise precision by averaging multiple ADC outputs before any filtering

A CPS needs to process camera images, run a complex AI model to identify objects, and send results over the internet. Which processing unit from the options best fits this scenario, and why?

• Microcontroller (MCU) because it is a compact, low-cost single-chip computer ideal for dedicated real-time control tasks

• Microprocessor (MPU) because it can run full-fledged operating systems and handle complex tasks, graphics, and networking

• Programmable Logic Controller (PLC) because it is ruggedized for harsh industrial environments and excels at real-time manufacturing control

• System on a Chip (SoC) because it integrates almost all computer components into a single chip for power efficiency

You must choose a processing unit for a harsh factory environment to reliably control a robotic arm that welds car parts at precise moments based on sensor data. Which option is most appropriate and what characteristic makes it suitable?

• Microcontroller (MCU) due to its self-contained design with RAM and Flash for low-cost tasks

• Microprocessor (MPU) due to its need for external RAM and ability to run Linux

• System on a Chip (SoC) due to its miniaturization and power efficiency

• Programmable Logic Controller (PLC) due to its ruggedized, industrial-grade design optimized for real-time control in harsh environments

A plant needs compact integration of computation, memory, radio communication, and sensor/actuator interfacing in a single package to minimize latency and wiring complexity. Based on the diagrams, which platform best fits this requirement?

• Programmable Logic Controller (PLC) cabinet with discrete modules

• System on a Chip (SoC) integrating digital blocks (CPU, RAM), analog/RF, MEMS sensors/actuators, and RF/optical communication

• Standalone microcontroller board with external sensors and separate RF module

• Industrial PC connected to distributed I/O racks

A CPS designer needs a simple board-to-board link between a GPS module and an Arduino. Which wired protocol from the list best fits this requirement and why?

• UART/USART, because it is a simple two-wire TX/RX protocol suited for board-to-board communication

• I2C, because it uses two wires and is faster than SPI for high-speed data

• SPI, because it uses four wires and supports many slaves on a bus

• I2C, because it is full-duplex and optimized for short-distance high-speed ADC data

In the UART diagram showing two devices labeled UART 1 and UART 2, which pins must be cross-connected to enable one-way data transfer from UART 1 to UART 2?

• Tx of UART 1 to Tx of UART 2

• Rx of UART 1 to Rx of UART 2

• Tx of UART 1 to Rx of UART 2

• Rx of UART 1 to Tx of UART 2

The data buses feeding UART 1 and UART 2 are labeled bit 0 through bit 7. What does this labeling most directly indicate about the data width entering/exiting each UART?

• 4-bit parallel data

• 8-bit parallel data

• 16-bit parallel data

• Serial data only