Q.1 Which sensor is most commonly used to measure joint angle in a rehabilitation exoskeleton?
Force Sensitive Resistor (FSR)
Potentiometer
Thermocouple
Photodiode
Explanation - Potentiometers provide reliable analog voltage proportional to rotation, making them suitable for joint angle measurement.
Correct answer is: Potentiometer
Q.2 In surface EMG (sEMG) based control of a robotic prosthetic hand, what is the primary purpose of the signal preprocessing step?
Increase the sampling rate
Remove motion artifacts and noise
Amplify the DC component
Convert the signal to digital
Explanation - Preprocessing (filtering, rectification, etc.) cleans the raw EMG signal to extract useful muscle activation information.
Correct answer is: Remove motion artifacts and noise
Q.3 Which type of actuator is typically preferred for lightweight upper‑limb rehabilitation robots?
Hydraulic cylinder
Pneumatic muscle
Series elastic motor
Stepper motor
Explanation - Series elastic actuators provide compliance and accurate force control while keeping weight low, ideal for wearable robots.
Correct answer is: Series elastic motor
Q.4 What does the term “impedance control” refer to in rehabilitation robotics?
Controlling the robot’s speed only
Maintaining a constant position
Regulating the dynamic relationship between force and motion
Adjusting the robot’s battery voltage
Explanation - Impedance control shapes how the robot reacts to external forces, important for safe human‑robot interaction.
Correct answer is: Regulating the dynamic relationship between force and motion
Q.5 Which international standard specifically addresses safety requirements for medical robots used in rehabilitation?
ISO 13485
IEC 60601‑1
ISO 14971
ISO 10218‑2
Explanation - ISO 13485 focuses on quality management systems for medical devices, including rehabilitation robots, ensuring safety and compliance.
Correct answer is: ISO 13485
Q.6 A rehabilitation robot uses a 12‑V Li‑ion battery rated at 5 Ah. What is its maximum energy storage capacity?
60 Wh
12 Wh
5 Wh
120 Wh
Explanation - Energy = Voltage × Capacity = 12 V × 5 Ah = 60 Wh.
Correct answer is: 60 Wh
Q.7 Which control architecture enables a therapist to set a variable assistance level during gait training?
Open‑loop control
Fixed‑gain PID control
Adaptive impedance control
Bang‑bang control
Explanation - Adaptive impedance can modify assistance based on patient performance, allowing therapists to adjust support in real time.
Correct answer is: Adaptive impedance control
Q.8 In a lower‑limb exoskeleton, which joint typically requires the highest torque output?
Ankle
Knee
Hip
Toe
Explanation - The hip joint supports the largest portion of body weight and must generate the greatest torque during stance phase.
Correct answer is: Hip
Q.9 What is the main advantage of using a cable‑driven transmission in a rehabilitation robot?
Higher stiffness than gears
Reduced back‑drivability
Lightweight and remote actuation
Simpler control algorithms
Explanation - Cables allow actuators to be placed away from the moving limb, reducing limb‑attached mass and improving comfort.
Correct answer is: Lightweight and remote actuation
Q.10 Which of the following is a common metric used to assess the effectiveness of a robot‑assisted therapy session?
Battery voltage
Range of motion (ROM)
Signal‑to‑noise ratio
Clock speed of the microcontroller
Explanation - ROM measures the angular displacement achieved during therapy, directly reflecting patient progress.
Correct answer is: Range of motion (ROM)
Q.11 When designing a wearable robot for hand rehabilitation, why is it important to use low‑profile force sensors?
To increase the robot’s weight
To improve tactile feedback
To reduce power consumption
To keep the device unobtrusive and comfortable
Explanation - Low‑profile sensors minimize bulk, ensuring the device does not hinder natural hand movements.
Correct answer is: To keep the device unobtrusive and comfortable
Q.12 Which algorithm is widely used for real‑time classification of EMG patterns in prosthetic control?
K‑means clustering
Linear discriminant analysis (LDA)
Monte Carlo simulation
Fast Fourier Transform (FFT)
Explanation - LDA provides fast, computationally efficient classification of EMG features for prosthetic control.
Correct answer is: Linear discriminant analysis (LDA)
Q.13 A rehabilitation robot employs a 6‑axis force/torque sensor at the end‑effector. What does this sensor measure?
Only linear forces
Only angular torques
Both linear forces and angular torques
Temperature and humidity
Explanation - A 6‑axis FT sensor provides three forces (X, Y, Z) and three torques (roll, pitch, yaw).
Correct answer is: Both linear forces and angular torques
Q.14 Which type of feedback is most effective for encouraging patient participation during robot‑assisted gait training?
Auditory feedback
Haptic (force) feedback
Visual feedback
Olfactory feedback
Explanation - Force feedback directly informs the patient about interaction forces, enhancing engagement and motor learning.
Correct answer is: Haptic (force) feedback
Q.15 In a functional electrical stimulation (FES) system integrated with a rehabilitation robot, what is the primary role of the robot?
Generate electrical pulses
Provide mechanical assistance and guidance
Monitor heart rate
Supply power to the FES device
Explanation - The robot assists movement while the FES activates muscles, together facilitating coordinated therapy.
Correct answer is: Provide mechanical assistance and guidance
Q.16 Which power electronics component is essential for driving a DC motor in a wearable exoskeleton?
Rectifier
H‑bridge driver
Transformer
Zener diode
Explanation - An H‑bridge allows bidirectional control of motor voltage and current, enabling forward and reverse motion.
Correct answer is: H‑bridge driver
Q.17 What is the main benefit of using a model‑based predictive controller for a rehabilitation robot?
Simplifies hardware design
Eliminates need for sensors
Anticipates future states for smoother motion
Reduces computational load
Explanation - Predictive control uses a dynamic model to forecast system behavior, improving responsiveness and comfort.
Correct answer is: Anticipates future states for smoother motion
Q.18 Which communication protocol is commonly used for high‑speed data transfer between sensors and the main controller in rehab robots?
I²C
CAN bus
UART
SPI
Explanation - CAN bus offers robust, real‑time communication with error handling, suitable for safety‑critical robotic systems.
Correct answer is: CAN bus
Q.19 A therapist wants to limit the maximum torque a robot can apply to a patient's elbow to 5 Nm. Which control method is appropriate?
Open‑loop voltage control
Torque limiting via software saturation
Speed‑only PID control
Current‑free PWM
Explanation - Software saturation caps the torque command, ensuring the robot never exceeds the safe limit.
Correct answer is: Torque limiting via software saturation
Q.20 Which of the following is a key design consideration for a robot that assists stroke patients with reaching movements?
High payload capacity
Low latency in sensor feedback
Maximum operating temperature
Water resistance
Explanation - Fast feedback is crucial for synchronizing assistance with the patient’s intent during reaching tasks.
Correct answer is: Low latency in sensor feedback
Q.21 What does the term “back‑drivable” mean in the context of rehabilitation robot actuators?
The actuator can be driven in reverse only
The actuator can be moved manually when power is off
The actuator has built‑in brakes
The actuator uses hydraulic fluid
Explanation - Back‑drivability allows the robot to be safely moved by the patient or therapist without active power.
Correct answer is: The actuator can be moved manually when power is off
Q.22 Which type of filter is best suited to remove power‑line interference (50/60 Hz) from EMG signals?
Low‑pass filter
Band‑stop (notch) filter
High‑pass filter
All‑pass filter
Explanation - A notch filter attenuates a narrow frequency band, eliminating the 50/60 Hz mains hum while preserving the EMG spectrum.
Correct answer is: Band‑stop (notch) filter
Q.23 In a robot‑assisted treadmill therapy system, why is it important to synchronize the belt speed with the robot’s gait phase controller?
To reduce power consumption
To avoid slippage and maintain natural gait timing
To increase the robot’s weight
To simplify the user interface
Explanation - Synchronization ensures the patient’s foot placement matches belt movement, providing realistic gait training.
Correct answer is: To avoid slippage and maintain natural gait timing
Q.24 Which of the following is a primary advantage of using a soft robotic glove for hand rehabilitation?
Higher stiffness than rigid exoskeletons
Simpler electrical wiring
Conformable to finger shape and safe interaction
Requires no power source
Explanation - Soft robots can wrap around fingers, providing gentle assistance while reducing risk of injury.
Correct answer is: Conformable to finger shape and safe interaction
Q.25 A rehabilitation robot uses a 24‑V DC bus with a maximum current of 10 A. What is the maximum power the bus can supply?
240 W
2.4 kW
240 kW
24 W
Explanation - Power = Voltage × Current = 24 V × 10 A = 240 W.
Correct answer is: 240 W
Q.26 Which machine learning technique is commonly used for adaptive assistance in robot‑assisted therapy?
Support Vector Machine (SVM)
Reinforcement Learning (RL)
Principal Component Analysis (PCA)
K‑Nearest Neighbors (KNN)
Explanation - RL enables the robot to learn optimal assistance policies based on patient performance feedback.
Correct answer is: Reinforcement Learning (RL)
Q.27 In a functional electrical stimulation (FES) system, what is the purpose of a charge‑balanced biphasic pulse?
Increase muscle fatigue
Prevent tissue damage
Reduce pulse amplitude
Simplify circuit design
Explanation - Charge‑balanced biphasic pulses ensure net zero charge, minimizing electrochemical reactions that could harm tissue.
Correct answer is: Prevent tissue damage
Q.28 Which component converts the robot’s joint position into a digital signal for the controller?
Analog‑to‑Digital Converter (ADC)
Digital‑to‑Analog Converter (DAC)
Operational Amplifier
Inductor
Explanation - The ADC samples analog sensor outputs (e.g., potentiometers) and provides digital values for processing.
Correct answer is: Analog‑to‑Digital Converter (ADC)
Q.29 Why is modularity an important design principle for rehabilitation robots used in clinical settings?
It reduces the robot’s weight
It allows easy swapping of parts for different therapies
It eliminates the need for software updates
It increases battery life
Explanation - Modular designs let clinicians customize or replace modules (e.g., limb interfaces) to suit varied patient needs.
Correct answer is: It allows easy swapping of parts for different therapies
Q.30 Which biomechanical parameter is directly measured by a load cell placed under a footplate in gait rehabilitation?
Joint angle
Ground reaction force
Muscle activation
Temperature
Explanation - Load cells quantify the force exerted by the foot on the plate, representing the ground reaction force.
Correct answer is: Ground reaction force
Q.31 What is the role of a PID controller in a joint position control loop of a rehabilitation robot?
To provide only proportional gain
To regulate temperature
To compute corrective torque based on position error, its integral, and derivative
To convert analog signals to digital
Explanation - PID combines proportional, integral, and derivative actions to achieve accurate and stable position tracking.
Correct answer is: To compute corrective torque based on position error, its integral, and derivative
Q.32 Which of the following is a typical safety feature in wearable rehabilitation robots?
Over‑speed detection with automatic shutdown
Unlimited torque output
Non‑interruptible power supply
High‑gain open‑loop control
Explanation - Detecting excessive speed prevents accidental injury by stopping the robot promptly.
Correct answer is: Over‑speed detection with automatic shutdown
Q.33 A robot‑assisted elbow flexion task uses a sinusoidal reference trajectory. What is the main advantage of using a sinusoid?
It requires no sensors
It provides smooth, continuous motion for natural movement
It maximizes power consumption
It eliminates the need for controllers
Explanation - Sinusoidal trajectories emulate natural limb movement patterns, reducing abrupt changes.
Correct answer is: It provides smooth, continuous motion for natural movement
Q.34 Which sensor type can be used to detect slippage between a robotic exoskeleton footplate and the patient’s shoe?
Capacitive proximity sensor
Force sensitive resistor (FSR)
Gyroscope
Optical encoder
Explanation - FSRs detect changes in pressure distribution, indicating loss of contact or slippage.
Correct answer is: Force sensitive resistor (FSR)
Q.35 What is the main purpose of using a Kalman filter in processing sensor data for a rehabilitation robot?
To increase sensor noise
To estimate the true state by reducing noise and handling uncertainty
To convert digital signals to analog
To amplify the measured signal
Explanation - Kalman filters optimally combine model predictions and noisy measurements, yielding a cleaner estimate.
Correct answer is: To estimate the true state by reducing noise and handling uncertainty
Q.36 Which of the following is a common method for measuring muscle fatigue during robot‑assisted therapy?
Surface EMG median frequency shift
Battery voltage drop
Temperature rise of the robot
Encoder count overflow
Explanation - Fatigue causes a downward shift in EMG median frequency, serving as a non‑invasive indicator.
Correct answer is: Surface EMG median frequency shift
Q.37 A rehabilitation robot uses a 6‑DoF inertial measurement unit (IMU) on the limb. What information can the IMU provide?
Joint torque only
Linear acceleration and angular velocity
Battery state‑of‑charge
Water resistance level
Explanation - IMUs combine accelerometers and gyroscopes to output linear acceleration and rotational rates.
Correct answer is: Linear acceleration and angular velocity
Q.38 Which programming language is most widely used for real‑time control in rehabilitation robotics?
Python
MATLAB
C/C++
JavaScript
Explanation - C/C++ offers low‑level hardware access and deterministic timing needed for real‑time control.
Correct answer is: C/C++
Q.39 When a robot exoskeleton is powered by a brushless DC (BLDC) motor, which component is required to commutate the motor phases?
Hall‑effect sensor
Linear actuator
Stepper driver
Thermistor
Explanation - Hall sensors detect rotor position, allowing the controller to switch motor phases correctly.
Correct answer is: Hall‑effect sensor
Q.40 What does the term “assist‑as‑needed” (AAN) refer to in robot‑assisted rehabilitation?
Providing maximum assistance at all times
Giving assistance only when the patient cannot meet the movement goal
Turning the robot off during therapy
Increasing the robot’s speed continuously
Explanation - AAN promotes active patient involvement by supplying help only when required, encouraging motor learning.
Correct answer is: Giving assistance only when the patient cannot meet the movement goal
Q.41 Which type of encoder provides absolute position information without needing a reference reset?
Incremental encoder
Optical encoder
Absolute encoder
Quadrature encoder
Explanation - Absolute encoders output a unique code for each shaft position, eliminating the need for homing.
Correct answer is: Absolute encoder
Q.42 In a robot‑assisted therapy session, a therapist wants to track the patient’s progress over weeks. Which data representation is most suitable?
Raw sensor voltage values
Statistical summary (mean, standard deviation) of performance metrics
Binary on/off flags
Uncompressed video footage
Explanation - Aggregated statistics give clear, comparable insight into trends while reducing data volume.
Correct answer is: Statistical summary (mean, standard deviation) of performance metrics
Q.43 What is the purpose of a safety-rated soft‑stop in a rehabilitation robot’s firmware?
To increase the robot’s speed
To abruptly cut power
To decelerate the robot smoothly to a halt when a fault is detected
To enable continuous operation
Explanation - A soft‑stop reduces mechanical shock and protects the patient during emergency shutdowns.
Correct answer is: To decelerate the robot smoothly to a halt when a fault is detected
Q.44 Which of the following is an example of a passive element that can be incorporated into a rehabilitation robot to store energy?
Spring
Microcontroller
Battery
DC motor
Explanation - Springs can store and release mechanical energy, assisting motion without active power.
Correct answer is: Spring
Q.45 In a bilateral tele‑rehabilitation system, what is the main advantage of using force reflection from the remote robot to the user’s device?
Increases latency
Provides haptic perception of the remote environment
Reduces battery consumption
Eliminates the need for visual feedback
Explanation - Force reflection lets the user feel forces experienced by the remote robot, enhancing immersion and therapy effectiveness.
Correct answer is: Provides haptic perception of the remote environment
Q.46 Which component converts the digital control signal from a microcontroller to a variable voltage for a motor driver?
Digital‑to‑Analog Converter (DAC)
Step‑down regulator
Inductive coil
Relay
Explanation - A DAC translates digital values into analog voltages used by motor drivers for speed control.
Correct answer is: Digital‑to‑Analog Converter (DAC)
Q.47 A rehabilitation robot is required to operate for 2 hours continuously. If the average power consumption is 80 W, what is the minimum battery capacity needed (in Wh)?
40 Wh
160 Wh
320 Wh
80 Wh
Explanation - Energy = Power × Time = 80 W × 2 h = 160 Wh.
Correct answer is: 160 Wh
Q.48 Which of the following best describes a 'soft robot' in rehabilitation?
A robot made of metal alloys
A robot with flexible, compliant structures that conform to the body
A robot that operates at high temperature
A robot that uses hydraulic actuators only
Explanation - Soft robots use deformable materials, enhancing comfort and safety for patients.
Correct answer is: A robot with flexible, compliant structures that conform to the body
Q.49 What is the primary reason for implementing a 'dead‑band' in the control loop of a rehabilitation robot?
To increase system stiffness
To ignore small sensor noise around zero effort
To boost motor speed
To reduce battery voltage
Explanation - A dead‑band prevents the controller from reacting to insignificant fluctuations, improving stability.
Correct answer is: To ignore small sensor noise around zero effort
Q.50 Which type of control algorithm can directly map desired joint torques to motor currents in a robot exoskeleton?
Voltage‑mode control
Current‑mode (torque) control
Position‑only PID control
Open‑loop PWM
Explanation - Current is proportional to torque in electric motors, allowing precise torque regulation.
Correct answer is: Current‑mode (torque) control
Q.51 In the context of rehabilitation robotics, what does the acronym 'DoF' stand for?
Degree of Frequency
Depth of Field
Degree of Freedom
Delay of Feedback
Explanation - DoF refers to independent motions a robot can perform, such as translation or rotation axes.
Correct answer is: Degree of Freedom
Q.52 Which of the following is a typical use case for a robot‑assisted wrist rehabilitation device?
Assisting breathing exercises
Training pronation/supination movements
Measuring blood pressure
Providing auditory cues
Explanation - Wrist devices focus on rotational movements to restore functional forearm rotation.
Correct answer is: Training pronation/supination movements
Q.53 Why is it important to calibrate force sensors before each therapy session?
To increase sensor weight
To ensure accurate force measurements for safe assistance
To change the sensor’s color
To reset the robot’s battery
Explanation - Calibration eliminates drift and guarantees that the robot applies correct assistance levels.
Correct answer is: To ensure accurate force measurements for safe assistance
Q.54 A robot uses a pneumatic artificial muscle (PAM) as an actuator. Which characteristic is most advantageous for rehabilitation applications?
High power density and compliance
Unlimited range of motion
Zero maintenance
Immediate response without lag
Explanation - PAMs mimic natural muscle behavior, offering strong yet flexible actuation suitable for therapy.
Correct answer is: High power density and compliance
Q.55 What is the function of a ‘watchdog timer’ in the control electronics of a rehabilitation robot?
To increase processing speed
To monitor and reset the system if the software becomes unresponsive
To store patient data
To regulate battery temperature
Explanation - A watchdog timer ensures the controller restarts safely if it hangs, preserving patient safety.
Correct answer is: To monitor and reset the system if the software becomes unresponsive
Q.56 Which of the following best describes the purpose of ‘task‑space’ control in rehabilitation robotics?
Controlling each joint individually
Controlling the robot’s end‑effector position and orientation directly
Managing battery temperature
Setting the robot’s Wi‑Fi password
Explanation - Task‑space control focuses on the Cartesian coordinates of the point interacting with the patient.
Correct answer is: Controlling the robot’s end‑effector position and orientation directly
Q.57 In a robot‑assisted therapy platform, what is the main advantage of using wireless communication (e.g., BLE) between sensors and the controller?
Higher data bandwidth than wired connections
Reduced cable clutter and improved patient mobility
Eliminates the need for power supplies
Ensures zero latency
Explanation - Wireless links lessen tethering, making the system less restrictive for patients.
Correct answer is: Reduced cable clutter and improved patient mobility
Q.58 Which of the following is a common method to evaluate the usability of a rehabilitation robot?
System uptime percentage
System Usability Scale (SUS) questionnaire
Battery voltage measurement
Motor winding resistance
Explanation - SUS provides a standardized assessment of user satisfaction and ease of use.
Correct answer is: System Usability Scale (SUS) questionnaire
Q.59 A rehabilitation robot’s controller runs a control loop at 1 kHz. Why is this sampling rate important?
It matches the human heart rate
It ensures timely response to patient motions and stability of the control system
It maximizes battery life
It reduces the need for sensors
Explanation - High update rates allow the robot to react quickly, maintaining smooth interaction.
Correct answer is: It ensures timely response to patient motions and stability of the control system
Q.60 What is the primary benefit of implementing ‘mirror therapy’ using a robotic arm in stroke rehabilitation?
To increase the robot’s weight
To provide visual illusion that the impaired limb is moving normally
To heat the patient’s skin
To reduce power consumption
Explanation - Mirror therapy uses reflected movements to stimulate neuroplasticity and improve motor recovery.
Correct answer is: To provide visual illusion that the impaired limb is moving normally
Q.61 Which sensor would you use to detect the inclination of a patient's torso during seated balance training?
Ultrasonic distance sensor
Inclinometer (tilt sensor)
Thermistor
Hall‑effect sensor
Explanation - Inclinometers measure angle relative to gravity, suitable for posture monitoring.
Correct answer is: Inclinometer (tilt sensor)
Q.62 When integrating a robotic exoskeleton with a virtual reality (VR) environment, which data stream is essential for synchronizing the user’s movements?
Battery temperature
Joint angle feedback
LED brightness
Speaker volume
Explanation - Accurate joint angles allow the VR system to render the avatar’s motion in real time.
Correct answer is: Joint angle feedback
Q.63 What is the purpose of a ‘gain‑scheduling’ strategy in a rehabilitation robot’s controller?
To keep the gain constant
To adjust controller gains based on operating conditions like speed or load
To disable the robot
To change the robot’s color
Explanation - Gain‑scheduling improves performance across a wide range of dynamics.
Correct answer is: To adjust controller gains based on operating conditions like speed or load
Q.64 A therapist wants to monitor how much work a patient does during a session. Which measurement would best represent mechanical work?
Total torque applied by the robot
Integral of torque × angular displacement over time
Maximum motor speed
Battery voltage drop
Explanation - Work is the product of torque and angular displacement, integrated over the movement duration.
Correct answer is: Integral of torque × angular displacement over time
Q.65 Which of the following is a typical characteristic of a “soft‑stop” compared to a “hard‑stop” in rehabilitation robots?
Abrupt cessation of motion
Smooth deceleration to zero velocity
Increase in speed
No effect on motion
Explanation - Soft‑stops reduce impact forces, protecting the patient during emergency stops.
Correct answer is: Smooth deceleration to zero velocity
Q.66 Why might a rehabilitation robot use a variable‑stiffness actuator (VSA) instead of a fixed‑stiffness actuator?
To simplify the mechanical design
To adapt compliance to different therapy phases and patient needs
To increase the robot’s weight
To reduce the number of sensors
Explanation - VSA enables the robot to be more compliant during assistance and stiffer during resistance training.
Correct answer is: To adapt compliance to different therapy phases and patient needs
Q.67 In a rehabilitation robot, what does the term “latency” refer to?
The robot’s weight
The delay between sensor measurement and actuator response
The robot’s battery capacity
The number of joints
Explanation - Low latency is essential for timely assistance and safe interaction.
Correct answer is: The delay between sensor measurement and actuator response
Q.68 Which of the following is a key factor when selecting the gear ratio for an exoskeleton joint actuator?
Desired torque output vs. speed requirement
Color of the gear
Length of the power cable
Battery brand
Explanation - Gear ratio balances torque amplification against speed reduction to meet joint demands.
Correct answer is: Desired torque output vs. speed requirement
Q.69 A robot‑assisted ankle device measures dorsiflexion angle with an encoder. If the encoder has 4096 counts per revolution, what is the angular resolution in degrees?
0.088°
0.5°
1°
0.01°
Explanation - Resolution = 360° / 4096 ≈ 0.088° per count.
Correct answer is: 0.088°
Q.70 What is a major advantage of using a 3‑phase brushless motor in a rehabilitation exoskeleton compared to a brushed DC motor?
Higher maintenance due to brushes
Higher efficiency and lower electromagnetic interference
Lower torque capability
Increased acoustic noise
Explanation - Brushless motors eliminate brushes, reducing losses and noise, which is beneficial for patient comfort.
Correct answer is: Higher efficiency and lower electromagnetic interference
Q.71 Which of the following data formats is most commonly used for storing time‑series sensor data from a rehabilitation robot?
JPEG
CSV
MP3
PDF
Explanation - CSV (comma‑separated values) is simple, human‑readable, and widely supported for tabular sensor data.
Correct answer is: CSV
Q.72 In an EMG‑controlled prosthetic hand, what does the term ‘muscle synergy’ refer to?
Electrical interference from power lines
Coordinated activation patterns of multiple muscles
Battery charging method
Temperature of the skin
Explanation - Synergies capture how groups of muscles work together, simplifying control algorithms.
Correct answer is: Coordinated activation patterns of multiple muscles
Q.73 Why is it important to implement a ‘zero‑force’ calibration routine for a force‑feedback robot?
To increase robot speed
To ensure that the measured force is zero when no external load is applied
To change the robot’s color
To reduce battery consumption
Explanation - Zero‑force calibration eliminates offset errors, ensuring accurate force feedback.
Correct answer is: To ensure that the measured force is zero when no external load is applied
Q.74 A rehabilitation robot is designed to operate in a hospital environment. Which certification is most relevant to demonstrate electromagnetic compatibility (EMC)?
CE Mark
FCC Part 15
ISO 9001
UL 61010
Explanation - FCC Part 15 defines limits for electromagnetic emissions and susceptibility for electronic devices in the U.S.
Correct answer is: FCC Part 15
Q.75 What is the purpose of a ‘force envelope’ in robot‑assisted therapy?
To limit the maximum force the robot can apply based on patient safety thresholds
To increase robot speed
To change the robot’s color scheme
To store battery energy
Explanation - A force envelope defines safe force boundaries, preventing excessive assistance or resistance.
Correct answer is: To limit the maximum force the robot can apply based on patient safety thresholds
Q.76 Which type of sensor is commonly used to detect skin contact for a wearable rehabilitation device?
Capacitive touch sensor
Hall‑effect sensor
Infrared distance sensor
Thermocouple
Explanation - Capacitive sensors can sense the presence of a conductive object (human skin) without pressure.
Correct answer is: Capacitive touch sensor
Q.77 When a rehabilitation robot’s control loop is experiencing oscillations, which of the following tuning actions is most likely to improve stability?
Increase the proportional gain dramatically
Decrease the derivative gain
Increase the derivative gain
Remove the integral term
Explanation - Derivative action damps rapid changes, reducing overshoot and oscillations.
Correct answer is: Increase the derivative gain
Q.78 Which of the following best defines ‘human‑in‑the‑loop’ control in rehabilitation robotics?
The robot operates without any human input
The patient’s physiological signals influence the robot’s control decisions
The robot only records data
The robot controls the therapist
Explanation - Human‑in‑the‑loop uses bio‑feedback (EMG, force) to adapt robot behavior in real time.
Correct answer is: The patient’s physiological signals influence the robot’s control decisions
Q.79 A rehab robot’s joint uses a harmonic drive gearbox. What is a primary benefit of this gearbox type?
High back‑lash and low torque capacity
Compact size with high reduction ratio and low back‑lash
Ability to operate without lubrication
Increased electrical resistance
Explanation - Harmonic drives provide precise motion with minimal backlash, essential for smooth assistance.
Correct answer is: Compact size with high reduction ratio and low back‑lash
Q.80 Which of the following is an example of an indirect measure of patient effort during robot‑assisted gait training?
Ground reaction force magnitude
Motor voltage
Battery temperature
LED indicator status
Explanation - Ground reaction forces reflect how much the patient is loading the limb, indicating effort.
Correct answer is: Ground reaction force magnitude
Q.81 In a rehabilitation robot, why is it beneficial to implement a ‘fail‑safe’ mode that disengages actuation on fault detection?
To increase robot speed
To protect the patient from unintended movements
To reduce power consumption
To enhance visual feedback
Explanation - Fail‑safe ensures the robot cannot exert force when a fault occurs, maintaining safety.
Correct answer is: To protect the patient from unintended movements
Q.82 What does the term ‘haptic rendering’ refer to in the context of rehabilitation robotics?
Displaying graphics on a screen
Generating realistic force feedback to the user
Recording audio signals
Measuring temperature
Explanation - Haptic rendering computes and delivers tactile sensations that mimic real interactions.
Correct answer is: Generating realistic force feedback to the user
Q.83 Which of the following best describes a ‘soft exosuit’ compared to a rigid exoskeleton?
It uses inflatable bladders for actuation
It is made of textiles and flexible components that augment movement
It has higher power consumption
It requires a hard shell
Explanation - Soft exosuits are lightweight, wearable garments that provide assistance through cables and fabrics.
Correct answer is: It is made of textiles and flexible components that augment movement
Q.84 A robot‑assisted therapy system records EMG signals at 1 kHz. What is the Nyquist frequency for this sampling rate?
500 Hz
1 kHz
2 kHz
250 Hz
Explanation - Nyquist frequency = half the sampling rate, so 1 kHz / 2 = 500 Hz.
Correct answer is: 500 Hz
Q.85 Which factor is most critical when designing a rehabilitation robot for pediatric patients?
Maximum torque output
Adjustable size and weight to fit children’s bodies
High‑speed operation
Complex user interface
Explanation - Pediatric devices must be appropriately sized and lightweight to ensure safety and comfort.
Correct answer is: Adjustable size and weight to fit children’s bodies
Q.86 Why is redundancy (multiple sensors measuring the same quantity) often used in rehabilitation robots?
To increase the robot’s weight
To improve reliability and fault tolerance
To confuse the controller
To reduce power consumption
Explanation - Redundant sensors allow cross‑validation and continued operation if one fails.
Correct answer is: To improve reliability and fault tolerance
Q.87 In a robot‑assisted upper‑limb therapy device, which control mode would best support a patient who can initiate movement but needs assistance to complete the motion?
Position control with fixed trajectory
Assistive torque control based on user‑generated force
Open‑loop velocity control
Full lock mode
Explanation - Torque assistance supplements the patient’s effort, allowing them to finish the movement.
Correct answer is: Assistive torque control based on user‑generated force
Q.88 Which of the following is a key advantage of using a 3‑D printed custom socket for a prosthetic hand controller?
It reduces the need for sensors
It allows rapid, patient‑specific fit and low cost
It eliminates the need for batteries
It provides unlimited power
Explanation - Additive manufacturing enables quick fabrication of personalized interfaces.
Correct answer is: It allows rapid, patient‑specific fit and low cost
Q.89 A robot uses a 12‑bit ADC to digitize sensor signals. What is the minimum voltage resolution if the input range is 0–5 V?
0.0012 V
0.00012 V
0.012 V
0.12 V
Explanation - Resolution = Range / (2^bits) = 5 V / 4096 ≈ 0.00122 V.
Correct answer is: 0.0012 V
Q.90 Which of the following best describes the role of a ‘safety‑rated monitored stop’ in a rehabilitation robot?
Immediately cuts all power
Brings the robot to a controlled stop while monitoring the condition and allowing a safe restart
Speeds up the robot
Turns off the display
Explanation - Monitored stops ensure the robot halts safely and can be resumed after verifying safety.
Correct answer is: Brings the robot to a controlled stop while monitoring the condition and allowing a safe restart
Q.91 What is the primary advantage of using a wireless EMG system over wired electrodes in rehabilitation robotics?
Higher signal amplitude
Elimination of cable restrictions, improving patient comfort and range of motion
Reduced cost
Increased power consumption
Explanation - Wireless EMG frees the patient from tethering, enabling more natural movements.
Correct answer is: Elimination of cable restrictions, improving patient comfort and range of motion
Q.92 In a robotic gait trainer, which parameter is most directly related to the step length the patient achieves?
Belt speed
Joint torque limit
Controller sampling rate
Battery voltage
Explanation - Higher treadmill belt speed results in longer steps for a given cadence.
Correct answer is: Belt speed
Q.93 Why is it important to perform a ‘range‑of‑motion (ROM) calibration’ before each therapy session?
To increase robot temperature
To ensure the robot’s motion limits match the patient’s current capabilities
To change the robot’s color
To charge the battery
Explanation - ROM calibration prevents over‑stretching and tailors assistance to the patient’s present status.
Correct answer is: To ensure the robot’s motion limits match the patient’s current capabilities
Q.94 Which of the following is a typical metric for quantifying patient engagement during robot‑assisted therapy?
Number of therapist interventions
Time spent in active movement versus passive mode
Battery discharge rate
Motor temperature
Explanation - Higher active movement time indicates greater patient involvement and effort.
Correct answer is: Time spent in active movement versus passive mode
Q.95 A rehabilitation robot’s controller uses a real‑time operating system (RTOS). What is the main benefit of an RTOS in this context?
It provides deterministic task scheduling for timely control loops
It reduces hardware cost
It increases Wi‑Fi range
It adds graphical user interface features
Explanation - RTOS ensures that critical control tasks meet strict timing requirements, essential for safety.
Correct answer is: It provides deterministic task scheduling for timely control loops
Q.96 Which of the following is a common method for estimating the joint torque required for elbow flexion in a therapy robot?
Using a lookup table based on patient weight and arm length
Measuring ambient temperature
Counting encoder pulses only
Measuring battery voltage
Explanation - Biomechanical models relate limb geometry and load to required torque.
Correct answer is: Using a lookup table based on patient weight and arm length
Q.97 Why might a rehabilitation robot be equipped with an emergency stop button that is physically separate from the software interface?
To increase device cost
To allow immediate, hardware‑level shutdown independent of software failures
To make the robot louder
To improve battery life
Explanation - A physical E‑stop guarantees rapid de‑activation even if software is unresponsive.
Correct answer is: To allow immediate, hardware‑level shutdown independent of software failures
Q.98 In a robotic hand rehabilitation device, which actuator type provides the smoothest finger flexion for delicate tasks?
Stepper motor with microstepping
Pneumatic cylinder
Hydraulic actuator
Brushless DC motor with gear reduction
Explanation - Microstepping reduces torque ripple, delivering fine, smooth finger movements.
Correct answer is: Stepper motor with microstepping
Q.99 What is the purpose of implementing a ‘gain‑scheduling matrix’ in a multi‑DOF exoskeleton controller?
To vary controller gains based on each joint’s operating condition
To change the robot’s color
To increase battery voltage
To turn off sensors
Explanation - A gain‑scheduling matrix adapts gains per joint, enhancing performance across the workspace.
Correct answer is: To vary controller gains based on each joint’s operating condition
Q.100 Which of the following best describes the term “biofeedback” in the context of rehabilitation robotics?
Providing the patient with visual or haptic information about their own physiological signals
Increasing the robot’s speed automatically
Changing the robot’s battery type
Reducing the number of sensors
Explanation - Biofeedback helps patients become aware of and modify their own muscle activity or movement patterns.
Correct answer is: Providing the patient with visual or haptic information about their own physiological signals
Q.101 A robot‑assisted elbow device uses a torque sensor with a range of ±20 Nm and a resolution of 0.01 Nm. What is the smallest change in torque it can reliably detect?
0.01 Nm
0.1 Nm
0.001 Nm
1 Nm
Explanation - Resolution defines the smallest measurable increment; here it is 0.01 Nm.
Correct answer is: 0.01 Nm
Q.102 Which communication protocol offers deterministic real‑time performance and is often used in safety‑critical robot control networks?
USB
Ethernet TCP/IP
EtherCAT
Wi‑Fi
Explanation - EtherCAT provides high‑speed, low‑latency deterministic data exchange, suitable for robotic control.
Correct answer is: EtherCAT
Q.103 Why is it beneficial to include a ‘patient‑specific model’ in the controller of a rehabilitation robot?
To reduce the robot’s weight
To tailor assistance based on individual biomechanics for more effective therapy
To increase the robot’s power consumption
To simplify the user interface
Explanation - Personalized models improve the accuracy of assistance, matching the patient’s capabilities.
Correct answer is: To tailor assistance based on individual biomechanics for more effective therapy
Q.104 In a robot‑assisted gait trainer, what does the term “phase‑dependent assistance” mean?
Providing the same assistance throughout the gait cycle
Adjusting assistance level based on the current phase (e.g., stance or swing) of the gait cycle
Increasing battery voltage during training
Changing the robot’s color during operation
Explanation - Phase‑dependent assistance synchronizes help with natural gait events for more realistic training.
Correct answer is: Adjusting assistance level based on the current phase (e.g., stance or swing) of the gait cycle
Q.105 Which of the following is a common method for estimating the energy consumption of a rehabilitation robot during a session?
Measuring the total charge drawn from the battery (Ah) and multiplying by voltage
Counting the number of sensor readings
Measuring the temperature of the motor windings
Observing the robot’s LED blink rate
Explanation - Energy = Voltage × Ampere‑hours gives the total energy used.
Correct answer is: Measuring the total charge drawn from the battery (Ah) and multiplying by voltage
Q.106 Why might a rehabilitation robot integrate a force‑feedback loop with a variable impedance controller?
To make the robot heavier
To enable smooth interaction that can adapt stiffness based on patient effort
To increase the robot’s temperature
To disable safety features
Explanation - Variable impedance changes compliance in response to the patient, enhancing comfort and safety.
Correct answer is: To enable smooth interaction that can adapt stiffness based on patient effort
Q.107 Which type of sensor is most suitable for detecting slip between a patient’s foot and a robotic treadmill surface?
Force Sensitive Resistor (FSR)
Hall‑effect sensor
Accelerometer
Thermistor
Explanation - FSRs detect changes in pressure distribution, indicating loss of contact or slip.
Correct answer is: Force Sensitive Resistor (FSR)
Q.108 In a robot‑assisted hand therapy device, what is the purpose of implementing a “soft‑grasp” algorithm?
To apply maximum force at all times
To modulate grip force gently based on object size and patient capability
To increase the robot’s speed
To shut down the device
Explanation - Soft‑grasp adapts grip strength, preventing excessive force and promoting safe manipulation.
Correct answer is: To modulate grip force gently based on object size and patient capability
Q.109 What is a key reason to employ a low‑pass filter with a cutoff around 20 Hz on EMG signals used for robot control?
To remove high‑frequency noise while preserving the muscle activation envelope
To increase the signal’s amplitude
To convert the signal to DC
To add latency
Explanation - EMG power is concentrated below ~20 Hz after rectification; filtering reduces noise while keeping useful information.
Correct answer is: To remove high‑frequency noise while preserving the muscle activation envelope
Q.110 Which of the following design considerations is most critical for ensuring a rehabilitation robot can be used in a hospital’s MRI suite?
Using non‑magnetic materials and components
Maximizing motor speed
Increasing battery capacity
Adding bright LEDs
Explanation - MRI environments require equipment free of ferromagnetic parts to avoid hazards and image artifacts.
Correct answer is: Using non‑magnetic materials and components