Science: Robotics: Sensors, Actuators, and Decision Loops
How robots sense, act, and respond to their environment
Science: Robotics: Sensors, Actuators, and Decision Loops
How robots sense, act, and respond to their environment
Science - Grade 6-8
- 1
A classroom robot uses an ultrasonic sensor to detect a wall in front of it. When the wall is closer than 20 centimeters, the robot stops and turns left. Identify the sensor, the actuator, and the decision the robot makes.
A sensor gathers information, and an actuator causes movement or another physical action.
The sensor is the ultrasonic sensor. The actuators are the motors that stop the wheels and turn the robot left. The decision is to stop and turn left when the wall is closer than 20 centimeters. - 2
A robot vacuum senses dirt with a dust sensor. If the dust level is high, it increases suction power. Write this as an input-process-output chain.
The input is the dust level measured by the dust sensor. The process is the robot checking whether the dust level is high. The output is increasing the suction power. - 3
Explain the difference between a sensor and an actuator. Give one example of each from a robot you might see at school or at home.
Think of sensors as the robot's senses and actuators as the robot's muscles or tools.
A sensor detects information from the environment, such as light, distance, sound, or touch. An actuator makes something happen physically, such as a motor turning a wheel or a speaker making sound. - 4
A line-following robot has two light sensors, one on the left and one on the right. If the left sensor sees black and the right sensor sees white, what should the robot do to get back on the line? Explain your reasoning.
The robot needs to move toward the side where the line is detected.
The robot should turn left or slow the left wheel so it moves back toward the black line. This response helps center the robot over the line again. - 5
A robot arm has a gripper controlled by a motor. It also has a pressure sensor in the gripper. Why would the pressure sensor be useful when picking up a paper cup?
The pressure sensor helps the robot know how hard it is squeezing the cup. This is useful because the robot can grip firmly enough to hold the cup without crushing it. - 6
A robot is programmed with this rule: If the temperature is above 30 degrees Celsius, turn on the fan. Otherwise, keep the fan off. What will the robot do when the temperature sensor reads 28 degrees Celsius? Explain.
Check whether the sensor reading satisfies the condition in the rule.
The robot will keep the fan off because 28 degrees Celsius is not above 30 degrees Celsius. The condition for turning on the fan is not met. - 7
Draw or describe a decision loop for a robot that keeps a room's light level steady. The robot can read a light sensor and control a lamp.
A correct decision loop would read the light sensor, compare the reading to the desired brightness, turn the lamp up if the room is too dim, turn the lamp down or off if the room is too bright, and then repeat the sensing step. - 8
A delivery robot uses GPS to know its general location and wheel encoders to measure how far its wheels turn. Why might it need both types of sensors?
Different sensors can measure different kinds of information.
The robot might need GPS to know its approximate location over a large area and wheel encoders to track smaller movements more precisely. Using both sensors can help the robot navigate more accurately. - 9
A robot's touch sensor is stuck and always reports that it is being pressed. How could this affect the robot's behavior?
The robot may act as if it is constantly bumping into something. It might stop, back up, turn, or avoid moving even when nothing is actually touching it. - 10
A robot car uses a camera to find red stop signs. Name one challenge the camera system might have in the real world and explain how it could affect the robot's decision.
Think about weather, lighting, objects blocking the view, or signs that look similar.
One challenge is poor lighting, which could make the stop sign hard to detect. If the robot does not recognize the sign, it might fail to stop when it should. - 11
Study this simple robot rule: Read distance sensor. If distance is less than 10 centimeters, reverse motors for 1 second. If distance is 10 centimeters or more, drive forward. What is the robot trying to do?
The robot is trying to avoid obstacles. It drives forward when the path is clear and reverses when something is very close. - 12
Design a simple robot for watering a classroom plant. List one sensor it would use, one actuator it would use, and one decision rule it would follow.
The robot should measure something about the plant's needs before acting.
One possible design uses a soil moisture sensor, a water pump actuator, and the rule: if the soil moisture is too low, turn on the pump for a short time. This helps the robot water the plant only when needed.