(bright electronic music)

Hi, I'm Matt, and welcome to the VEX Classroom. Today, we're gonna be looking at some Frequently Asked Questions of the V5 Workcell and going over solutions to common problems that may arise with use. The purpose of today's video is to serve as a visual guide to see how one would actually follow along the steps found online with a Workcell in front of them. So without further ado, let's get into this.

The first question listed in the article is why is my V5 Workcell not moving accurately or shaking? Your kit comes with two motors, the 11 watt motor and the 5.5 watt motor. You can tell the difference between the two, as the 11 watt motor is much larger than the 5.5 watt motor. You can also see the shaft housing for the 11 watt motor is larger than the 5.5 watt motor. On the Workcell arm, you are to use the 11 watt motors. Having the 5.5 watt motors on your Workcell arm would not deliver the required power in order to move your arm accurately, thus, causing your Workcell to shake. So please be sure that you are using the 11 watt motors on the arm.

Next, if your Workcell is not moving accurately or shaking and you're using the correct motors, be sure that your Workcell is mastered correctly. If your Workcell is not mastered correctly, your Workcell arm does not have a designated home that it can go to after each program. Without this, it will not know where it is in regards to space, thus, it will not move accurately. Be sure, before each program, to double check your mastering values with your program and the brain.

The next step that may be causing your Workcell arm to not be accurate or shake is the turntable and the screws. Make sure all of the screws on your Workcell arm are not over tightened where motion is necessary. If they are over tightened, this will cause the metal on metal to rub, and it will not be able to move as smoothly. Anywhere there is a nut and a screw coming together, just be sure that it is not over tightened. The correct amount of tighten should not be able to be undone with fingers, but it should not be horrible to try and remove with a wrench and a screwdriver. So double check, on all parts of the arm where there is motion, they are not over tightened, as well as the turntable.

Let's look at this photo where the turntable screws are. There are four screws connecting the turntable of the arm to the base plate of the Workcell. Be sure that these are also not extremely tight. Again, if they are extremely tight, it will cause the turntable to be more pancaked down, not allowing the arm to move as smoothly. If you see your Workcell arm not moving as smoothly here, consider also lubricating your turntable. Let's check out an image where you would wanna do that. As we can see a disassembled turntable here, you would want to apply lubrication, such as lithium grease, where the highlighted image is shown. There will be less plastic on plastic contact, and your Workcell arm will be able to move more smoothly.

Lastly, ensure all of the rubber bands are located on your arm. The rubber bands can be thought of as the muscle of the arm, allowing for the retraction and the guidance of the range of motion. There are three rubber bands on your Workcell arm, one at the top, one at the bottom, and one on the turntable. For more steps, see the ending of this video on how to install these rubber bands.

The next question comes out of the mastering process of the arm. How would I know if my potentiometers are functioning correctly? If you have run the mastering program on your arm and it says it is failing, these are the steps you would take to resolve that. I have an arm here, which has two joints failing, joints two and four, I believe. We will be going over the steps on how you would actually fix this and run the arm install program, so let's see how that looks like.

Before we jump into the next step, the first thing that you should do is double-check that all of your three wires are connected with each other. Failure of these connections not being properly connected will result in a failure on your brain. Let's see what that would look like.

Here is a screen capture from the V5 brain of the devices menu showing the three wire ports. Notice in the red box, Analog Input A, the potentiometer for joint one, is reading 1863. This is what a functioning potentiometer would look like in the device's menu. Now, compare it with this value. You can see that the percentage is now at zero, implying that there is nothing in that port. So if you have a failing joint during your mastering process, please double-check that all of your three wire ports are properly connected with each other.

I have run the mastering program, and joints two and four are failing. I have double-checked that all of my three wire ports are properly connected, so what do I do next? This article titled, "Using the 'Arm Install' example project with the V5 Workcell," is very helpful in showing you the steps that are required to fix your Workcell, including the coast function, the hold function, and the target function. From using that article, I have now downloaded the Arm Install blocks example project that will get us back on track.

To start, I'm going to press run, which will show me all of my ports. I am leaving my brain on coast. I know it is hard to see, but we will show images after, and now I am going to remove my Workcell arm in order to get the potentiometers within passing range. A tip I like to do, when removing the arm, is insert the mastering jig. This will make sure that the arm is in its correct orientation whenever I am wanting to reinstall the arm. I am also using another shaft as a pusher mechanism that will get the second driving shaft out. Once that shaft is out, the arm is now able to be removed.

I am going to carefully remove the mastering jig, trying to leave it inserted, so I can reuse it whenever I am going to reinstall the arm. I have the arm off and the mastering jig all the way in. I am now going to make sure the gears are out of the way, which they are, the red gears, and I am going to use the target function in the program. You will see these metal gears spinning in order to become passing for the potentiometer values. Once they are in location, I'm going to press hold.

Back on the Frequently Asked Questions article, if your potentiometers spin indefinitely, with no end in sight, you may have a faulty potentiometer. The way to tell if you do, select coast and then target a couple of times, if that potentiometer is not getting within range. If all of your potentiometers are within passing, you are now able to reinstall the arm. Let's see how I can do that.

Because I left the mastering jig in, the arm is in a comfortable location to install it. What I'm going to do is make sure I have all of my spacers, that fell out whenever I was removing the arm, slightly moving the mastering jig to install it back into the Workcell base, and now, reinserting the mastering jig into the arm to hold it steady for me to insert the shafts that will actually hold the arm to the base. I'm about through in all, while I am still having the arm install program run, staying on the hold function.

Now that I have my mastering jig all the way in and my arm in its correct location, I'm going to reinsert the drive shaft. Putting it through the first hole, I know I'm going to need to insert the washer, which I find using pliers makes it very easy to do this, unless you drop it. So using a plier to hold the spacer, I am able to get it pretty much there, and then I am going to push the shaft, so that the shaft is now holding the spacer, like so. Once it's in, I'm going to continue pushing the shaft.

Thank you for following along with this guide. If you have any questions or need further assistance, please feel free to reach out.

Here comes the other drive shaft, which I find very helpful to use as a pusher, and just pushing that shaft in. With the second shaft, you can also go from the other direction, just to make sure that everything lines up, 'cause it's difficult to do sometimes. You can also use the back of a screwdriver.

Making sure that the red gears intermesh with the gears of the arm at the base. I am now inserting the shaft. This last gear right here is more difficult because it has a rubber band attached to it. You may need to adjust it from the bottom, hold it down there to get it in. If the roller at the end of the shaft is not rotated correctly, you can also use your spare shaft to rotate it into the correct orientation needed.

Now that I am through, I have had the arm install program running on hold. I now know that my arm is fully mastered correctly, and all of these potentiometers are functioning.

So to recap this step, if your arm has failed the mastering process and you need to rerun the arm install program in order to get your joints within passing range, double check that all of your three wire connections are fully connected. You can double check on the device's menu to see if it is giving a reading or not. Double check those. You can use a spare shaft to remove the shaft holding the arm, take the arm off, run the arm install program, select target then hold to get the potentiometers within range. If your potentiometers do not get within range, that is how you would know you have a faulty potentiometer. If your potentiometers are within range, select hold and reinsert the arm, install it, you're good to go.

Next comes my favorite topic. Why am I seeing no difference between Linear and Joint move? Let's take a look. If you are running the lab, in which you are trying to differentiate between Linear and Joint move, you are seeing no difference, follow these steps. Ensure that your Workcell is built correctly, mastered, your Workcell turntable is lubricated, if it needs it, all of the motion screws are not over tightened, and the rubber bands, that are the muscle of the arm, are installed.

Try this step. So, I have written and downloaded an example project, that will show us first a Linear move and then a Joint move, followed with a move to show us what the robot has drawn. If your Linear and Joint move looks something like this, try this step. The demonstration we just watched was performed with this code block. Notice the y values and how they are all smaller. If your Workcell is showing the same results as what we just saw in the video, try increasing your y values to be larger, such as these.

Let's see what this would look like. Originally remember, our Workcell was picking points about here and here, trying to show the difference between Linear and Joint move. By increasing the y coordinates, which are, as you remember, in inches shown here, to about -8 to +5, let's see the results that this now produces.

Here's Linear move

followed by Joint move,

a vast difference between the two.

Remember, you can also use the Right Hand Rule to determine the coordinates. You have positive x, positive y, and positive z going into the screen. It might be confusing, as you would think you are looking at the Workcell like this, that your Right Hand Rule is this. You must remember that the Right Hand Rule is position from your Workcell arm. Again, try increasing your y values to larger inch coordinates and see the difference.

The difference between Joint and Linear move is characterized by the path that the arm takes. With Joint move, only one motor is spinning, therefore, the tool tip path is not known as much as Linear move. Joint move may be faster, but with Linear move, you know from one point to another, your robot end effector will make a straight line between those two points.

A tip that you can use to determine which code block your arm is running at that very moment, which is not very known, is by looking at these red gears here. During Linear move, they will be fluctuating in order to keep the marker to remain in a straight line. During Joint move, remember, only one motor is spinning, so none of these will be moving. Let's see if you can determine which move is Linear move, by the red gears moving, and which move is Joint move, by looking at which gears are moving.

To recap, try increasing your y values. Remember to use the Right Hand Rule to determine which coordinate you want to mess with, and remember how the coordinates actually come about, whether it be when it is inches on your Workcell.

Lastly, how do I install the rubber bands? We get it, installing rubber bands is tricky. Check out the animations found online that will guide you through it. In the animations, they used a twist tie, commonly found on wire bundles that you may have left over in your kit. With this twist tie, you can wrap it around the rubber band, and now you have a more sturdy contraption that will allow you to guide your rubber band through the holes on the Workcell. Let's check them out.

So I have opened the Installing V5 Workcell Rubber Bands article, and it shows me three animations that actually show you how to install these rubber bands. The black string they are using in this animation is the twist tie I have just introduced to you. Using the twist tie allows you to guide the rubber band through the small holes and will make your life a lot easier when installing these rubber bands. These rubber bands deteriorate over time, so it is not uncommon for them to break with use. Simply watch these videos and use these tricks to reinstall your rubber bands. You can also use screwdrivers or anything else you feel would be necessary to replace the twist tie.

I hope by watching this video, your Workcell's now in working order, and you've learned some tricks when navigating some of these problems.

If you've enjoyed, my name's Matt, till next time, thank you.

(bright electronic music)