ECET 365 Week 4 Complete DeVry
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ECET 365 Week 4 Complete DeVry
ECET 365 Week 4 Power Systems DeVry
ECET 365 Week 4 Discussions
WEEK 4: ALTERNATE BATTERY TYPES
What
are the advantages and disadvantages of using NICAD, NIMH, lithium, or sealed
lead-acid rechargeable batteries?
WEEK 4: SUBSYSTEM POWER REQUIREMENTS
https://bit.ly/2DkEVwn
Page
242, Problem 4.10. Page 586, Problem 11.5c,g. Page 589, D11.20, D11.21
Don’t
forget to submit your assignment.
ECET 365 Week 4 COURSE PROJECT (DUE IN WEEK 8)
Review
the Course Project Overview under the Introduction & Resources area for an
overall description of the Course Project, grading rubric, and deliverables.
The
Lab is focused on tasks required to develop a power supply system for the
project.
ECET 365 Week 4 Lab
Lab 4:
Converting Requirements to a Work Schedule
Objectives
- Test the main power supply of the Smart Car or robotic system.
- Test the subsystem power supplies and determine if a separate battery system is required for the subsystems.
- Robotic Car Kit
- Freescale Tower Kit with S12G128 CPU board
- PC with IDE software (e.g. CodeWarrior Development Studio V5.1)
- Alternative Robotics Kit or other kit if applicable
Introduction
- A project system contains several subsystems that require power. The Robotic Car Kit, for example, has a visual sensor subsystem, a steering subsystem, a CPU board subsystem, and a motor control subsystem. It may be possible to run the subsystems from one main power supply (e.g. a 9V or 12V rechargeable battery). Warning: DO NOT POWER DC MOTORS USING THE POWER FROM THE DRAGON BOARD OR POWER BOARD. USE A SEPARATE POWER SUPPLY.
- The Robotic Car uses 4 AA batteries. The power supply on the Primary elevator board accepts a 5 V input to produce 3.3V for the Tower. Four new alkaline AA batteries have a starting voltage of 1.61 X 4 = 6.44 V. This is a bit too much for the power supply. The power supply was tested at this voltage for a short time, but the current drain was 100 ma. The current drain was much less, as the voltage input approaches 5 V.A rechargeable NiMH battery has a peak voltage of 1.35 V. This gives a total voltage of 1.35 x 4 = 5.4V. This is much better. If you don’t see the wisdom of rechargeable batteries, you could drain the non-rechargeable batteries using a resistor (greater than 10 ohms) until the voltage is 1.35 V.
- It is also possible that the subsystems might require a separate battery system to avoid interference from the large motor pulses powered by the main power system.
- This lab will evaluate the power provided to the subsystems to determine if a separate battery is needed.
- Similar procedures would be used for a robotics project with subsystems.
Deliverables
Answer all
questions in Week 4 Lab Cover Sheet here (Links
to an external site.)Links to an external site..
Submit
your Week 4 Lab Assignment.
You
can also download the cover sheet for Week 4 Lab in the Files section of the
Course Menu.
Required
Software
CodeWarrior
Development Studio for S12(x) V5.1
Lab Steps
STEP 1:
Procedures
- Robotic Car Subsystems
- The interacting subsystems are the visual sensor subsystem, the steering subsystem, the motor subsystem, and the CPU board subsystem. We need to ensure that the motor subsystem does not affect the other systems.
- Set the assembled car on blocks so that the motor wheels can move freely. Consider that the front wheels must have room to move.
- Load the Robotic Car program into the CPU board. Ensure that the visual sensor inputs and outputs are connected to the CPU board. Also, ensure that the H-Bridge inputs are correctly connected.
- In a previous lab, we have tested the steering of the front wheels with an index card that has a 1-inch-wide stripe down the center of the card. This time, we will test the system with the wheels powered.
- Test the system with the subsystems powered, but the motor power to the H-bridge disconnected. Single-pole single-throw switches are recommended, but you can just disconnect the appropriate wires. Troubleshoot the system if it does not operate satisfactorily. Once the visual system works correctly, proceed to the next step.Note: These procedure steps can be performed whether the Tower system has been mounted on the Robotic Car chassis or not. It is recommended that the Tower be mounted on the chassis. Otherwise, the system is a confusing pile of wires. Nevertheless, it can be tested in such a manner. See the Robotic Construction Notes in the Files section of the Course Menu.
- Again, test the steering system, but turn the motor power on. The H-bridge is sending large pulses to the motor. If the subsystems are connected to the same battery as the motor power subsystem, the motor pulses may interfere with the steering subsystems. The Robotic steering works by stopping the motor on one side when the sensor on the other side detects the white background of the foam board track.
- If there is no interference, proceed to step 8. If there is interference such that the steering is not working correctly, use the oscilloscope to observe the power going to the subsystems. First, try the power going to the CPU board. The power supply on the Tower primary elevator provides the 3.3V to the protoboard and CPU board. Check the 3.3V bus for interference.It may be that a few more capacitors on the subsystem power lines may reduce the noise enough for the steering to work correctly. Note that you can add filter capacitors (tens of microfarads) before and after the voltage regulators. Consider the filter shown in the Robotic Construction Notes (see the Files section of the Course Menu).If not, you may consider a separate battery for the subsystems. The batteries are heavier than the capacitors. If a separate battery does not work, go back to step 5 and verify that the system works without the motor running. If running the motor with separate batteries for motor and subsystem, check for wiring and connection errors. Again, the oscilloscope is very useful for tracking noise pulses. When you have a correctly working system, proceed to step 8.
- If the steering works correctly with the motor running, and you haven’t done so already, mount the tower system on the Smart Car chassis. See the Robotic Construction Notes document in the Files section of the Course Menu.
- Observations
- For each subsystem, determine the actual current draw. If a sensitive ammeter is not available, use a small (0.1 or 1 ohm) resistor in series with the power lead. Measure the voltage across the resistor and calculate the current using Ohm’s Law (I = V/R).
- Video sensor _____
- Servo _____
- CPU board _____
- Motor _____
- Sketch the subsystem power voltages displayed by the oscilloscope. If noise was discovered and reduced, sketch the display before and after the noise was reduced.
- Calculate the expected operating time for the system. Ensure that the motor power operating lifetime will not exceed the CPU board operating lifetime
Motor System
Lifetime _____
CPU Board Lifetime _____
CPU Board Lifetime _____
- Let the system run until either the CPU board or the motor stops running. If the CPU board stops before the motor does, increase the capacity of the CPU board power supply.
Instructions
Here is some
information about your Quiz.
- This quiz covers CO 5 and Chapters 4, 11.
- This quiz is worth 20 total points, which include the following questions:
- 3 multiple-choice questions at 5 points each;
- 1 short-answer question at 5 points each; and
- You have 60 minutes to finish the quiz.
- Here is a reminder to SAVE frequently, because when the time limit is reached, you will automatically be exited from the exam.
- This quiz contains one page.
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