In the next set of program, we create a loop called Slow Down. Inside this loop, readings from the Ultrasonic or Infrared proximity sensor block are sent to a Math block (to take the negative of the position values so that the robot moves forward) and then sent to the power input of a Move Steering block. We can have the loop end when it reaches our desired stopping distance as shown in the following screenshot:
Instead of using the exact values of the output of the sensor block, we can use the difference between the actual position and the desired position to control the Move Steering block, as shown in the following screenshot. This difference is called the error. We call the desired position the setpoint. In the following screenshot, the setpoint is 20. The power is actually proportional to the error or the difference between the positions. When you execute this code, you will also find that if the robot is too close to the wall, it will run in reverse and back up...
