Unit 5: Control and Programming Elements - Practice Quiz

1 What is a main characteristic of an open-loop control system?

2 How does a closed-loop robot controller respond to an error?

3 What is feedback in a robot control system?

4 Which component commonly provides feedback about a robot's position?

5 What does PID stand for in PID control?

6 Which PID term responds to the accumulated error over time?

7 What is the basic purpose of motion planning?

8 What should a mobile robot's planned path normally avoid?

9 What is a variable in a robot program?

10 Which programming structure repeats a set of robot instructions?

11 Which language is commonly used for robotics and ROS development?

12 Which programming language is popular in robotics because of its readable syntax and extensive libraries?

13 What is an embedded system?

14 Which task is commonly performed by an embedded robot controller?

15 What is an Arduino board primarily based on?

16 How is a Raspberry Pi commonly classified?

17 What is ROS mainly used for?

18 What is a node in ROS?

19 What is the purpose of a Human–Robot Interface?

20 Which device can be part of a Human–Robot Interface?

21 A mobile robot must maintain a constant wheel speed while moving from a smooth floor onto a carpet. Which control approach is most suitable?

22 A robot arm uses a timer to run its motor for two seconds whenever it must rotate approximately . What is the main limitation of this open-loop method?

23 In a negative-feedback position controller, the reference angle is and the measured angle is . If error is defined as reference minus measurement, what error should be supplied to the controller?

24 After replacing a robot's position sensor, the motor moves farther away from the target whenever an error occurs. What is the most likely cause?

25 A proportional controller leaves a small constant position error when a robot joint holds a load. Which PID term is commonly added to reduce this steady-state error?

26 A PID controller uses . If , , , , , and , what is ?

27 A wheeled robot has an occupancy grid and must find a low-cost collision-free route to a known goal. Which algorithm is most appropriate?

28 Why is configuration space useful when planning the motion of a multi-joint robot arm?

29 A service robot must switch among the behaviors Idle, Navigate, Deliver, and Recharge based on events. Which programming structure best organizes this behavior?

30 A robot's obstacle sensor is checked only after a long arm movement function finishes. Which design change would most improve responsiveness?

31 A robotics team needs fast prototyping for computer-vision experiments and later requires high-performance motor-control code. Which language pairing is most appropriate?

32 Why is C or C++ commonly used to program microcontrollers in robots?

33 A wheel encoder generates brief pulses that must be counted even while the processor performs other calculations. Which embedded technique is most suitable?

34 A robot controller may occasionally freeze because of unexpected software faults. Which embedded feature can automatically reset it if normal execution stops?

35 A robot needs precise microsecond-level pulse generation for a servo and high-level image processing. Which division of work is most appropriate?

36 Why might a Raspberry Pi running a standard Linux system be less suitable than an Arduino for directly generating strict real-time motor pulses?

37 In ROS, a camera node continuously sends images that several processing nodes need to receive independently. Which communication mechanism should be used?

38 A ROS navigation command may take a minute, should report progress, and must support cancellation. Which ROS communication pattern is most suitable?

39 An operator remotely controls a robot near people. Which interface feature most directly improves safety during unexpected motion?

40 In a shared-control wheelchair, the user chooses the general direction while the robot avoids nearby obstacles. What is the main benefit of this interface?

41 A robot joint has plant transfer function and controller in unity negative feedback. A disturbance is added directly to the plant output. What is the closed-loop transfer function from to the measured output ?

42 A mobile robot uses wheel-encoder feedback to move exactly . On a slippery surface, its wheels rotate by the expected amount while the chassis travels only . Which modification most directly closes the loop around the actual controlled quantity?

43 A discrete integrator satisfies . Because of a one-sample delay, the feedback law is . For constant , which range of makes the error dynamics asymptotically stable?

44 A stable closed-loop position system contains integral action and measures , where is an unknown constant sensor bias. If the reference is constant and the actuator does not saturate, what steady-state true output should be expected?

45 For unity feedback, let and , with all three gains positive. Which additional condition is necessary and sufficient for asymptotic closed-loop stability?

46 A PID-controlled robot arm is commanded far beyond its reachable angle, so the actuator remains saturated for several seconds. When the reference returns to a reachable value, the arm overshoots severely. Which modification most directly addresses the cause?

47 An A* planner uses path cost equal to terrain cost plus a nonnegative turning penalty. Every translational path segment costs at least units per meter. Which heuristic is guaranteed to be admissible and consistent when is Euclidean distance to the goal?

48 A differential-drive robot is planned by linearly interpolating between configurations . One interpolated edge translates the robot sideways while holding constant. What is the fundamental issue?

49 An interrupt updates a multiword encoder count and its timestamp, while the main control loop reads both values. Rarely, the loop obtains a new count with an old timestamp. Which design best guarantees a coherent pair on a small MCU?

50 Navigation, teleoperation, and collision avoidance can each publish motor commands asynchronously. Which software architecture most reliably prevents stale or conflicting commands from reaching the actuators?

51 A robot performs vision-based planning and also runs a motor-current loop with a strict deadline. Which language allocation is generally the most defensible?

52 A C++ perception node sends data to a Python planning node through a generated message interface. The planner occasionally misses its deadline even though both algorithms are fast. Which cross-language factor must be investigated first?

53 A 32-bit millisecond timer wraps around, and both now and last are unsigned 32-bit values. Which condition correctly tests whether at least period milliseconds have elapsed, provided `period < 2^{31}$?

54 On an 8-bit microcontroller, an ISR increments a 16-bit counter while the main loop reads it. The counter is declared volatile, but occasional corrupted values still occur. Why?

55 An Arduino board uses logic while a Raspberry Pi uses non--tolerant GPIO. What is the safest general method for a bidirectional digital connection?

56 A robot requires image processing, network communication, and a deterministic wheel-control loop. Which partition best matches the typical strengths of a Raspberry Pi and an Arduino-class microcontroller?

57 A ROS-based navigation request may run for a minute, should report progress, and must be cancellable when an obstacle appears. Which communication abstraction is the best fit?

58 A camera observes point at time on a moving robot. With transform notation mapping coordinates from frame to frame , which expression correctly obtains the map-frame point?

59 A robot is teleoperated over an unreliable wireless link. If control packets stop arriving, which interface behavior best satisfies fail-safe design?

60 In shared autonomy, an operator commands forward motion while the autonomy detects an imminent collision. Which design best balances operator authority, safety, and mode awareness?