Vex V5 Control Systems

Vex V5 Control Systems

By REBECCA HUMBARGER

​A system in which the output does not control the action of the system; a non-feedback system.  

open loop control system

A system in which the output controls the action of the system; a feedback system.

closed loop control system

Multiple Choice

Which type of system is known as a feedback system?

• open loop control system

• closed loop control system

• both of these

• neither of these

Multiple Choice

An open loop control system is one in which

• there is no output

• the output controls the action of the system

• the output does not control the action of the system

• the length of the cycle is not pre-determined and varies from use to use

• Input. (a predetermined set of instructions for the robot to follow, i.e. the code)

• Controller. (the brain)

• Controlled process. (e.g. the purpose of the action you want the robot to perform)

• Output. (the end result of the predetermined set of instructions, completed without feedback)

Open Control Loops have 4 parts:

Multiple Choice

Why is it useful to set up an open control loop for performing a process?

• when you turn it on it will stay on and do only one thing until you turn it off, like a fan

• to adapt its behavior until a desired end-result is reached

• to detect feedback from the system and modify future behavior

• it will perform a task without an operator once it has started without feedback

The Vex V5 brain is programmed using the coding language called Python in the editor found at https://codev5.vex.com/.

Programming the brain

The Python code is programmed using text in the V5 editor. It is standard practice to set up a header composed of comments in any python program.

Reorder

Reorder the following parts of the header in Python code:

• line of dashes followed by a blank line

• author

• date created

• description

• blank line followed by a line of dashes

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

The first thing you will do when coding is add devices you have on your robot, including smart motors, bump switches, sonor sensors, vision sensors, magnets, or pens.

A closed-loop control system is more complicated. it includes steps for the following:
Input: Baseline reading or measurement.

• Controller: Device that responds in specific ways depending upon the input.

• Control Signal: Message sent by the controller to the actuator depending upon what conditions were met.

• Actuator: Device that responds to a control signal.

• Process: Operation or activity resulting from the actuator performing its function.

• Output: Controlled condition or state resulting from the intended process.

• Feedback: Measurements reported to the controller to determine whether the output has met the desired criteria.

Match

Match the closed control loop used in aelectric oven to the actual aspects of how a stove operates.

• controller

• control signal

• actuator

• process

• output

device that responds to feedback

message from controller to actuator

device that responds to control signal

activity resulting from the actuator

state resulting from the process

• device that responds to feedback

• message from controller to actuator

• device that responds to control signal

• activity resulting from the actuator

• state resulting from the process