【EP3】【VEXIQ】Build Your Chassis!! – Construction

Hello! Welcome back to IntroVex, your robotics guide to Vexcellence.

In the past two episodes, we talked about the gear ratios and the difference between sprockets and gears. This time, we are moving on to constructing a full chassis. I'll be introducing the parts you could use to construct your chassis based on your needs, and take you through important steps for building.

How many wheels to use?

First, we have to think about the wheels. There are many factors for us to consider: the amount, the type, and the position. It is important to plan before construction to avoid possible conflicts while building.

First, it is the number of wheels we use. In VEX IQ, we typically use 2 wheels on each side of the chassis. Since robots are light, 4 wheels are enough to support the chassis. If we used 6 wheels with the same motors, it would increase friction, making the robot harder to turn. In rare cases where a robot is so heavy that wheel axles start to bend, a 6-wheel chassis can help spread the load and reduce stress.

Next, it’s the type of wheels to use. In VEX IQ, there are two main types of wheels: traction wheels and omni wheels. The difference is that traction wheels have higher friction and grip, while omni wheels have rollers that allow them to slide sideways more easily.

In competitions, we typically use omni wheels on the chassis because they reduce turning friction and make the robot drive more smoothly. The trade-off is that omni wheels provide less traction than regular traction wheels, which can reduce pushing power and result in less precise movements, but the smoother movement usually makes them the better choice.

Finally, it’s the position of the wheels. The main goal is to keep the robot stable and balanced. By placing the wheels near the front and back edges of the chassis, the weight is evenly supported, and the robot is less likely to tip forward or backward. However, wider is not always better; finding the right balance between stability and maneuverability is more important.

How many motors to use?

Now it’s time to decide how many motors to use on the chassis. This depends largely on how many motors are needed for other subsystems. In VEX IQ, a robot can use up to 6 motors total. For example, if the intake uses 1, the scoring system uses 2, and the endgame system uses 1, then only 2 motors remain for the chassis. In some cases, using pneumatic pistons for certain functions can help save motors.

Since the setup varies by game, the most common and simple solution is a two-motor chassis, with one motor on each side powering two wheels.

Constructing a chassis

When constructing the chassis, we need to decide on many things: the length of the beams, the width of the chassis, the gears to use, and the motor position, etc. Let’s go through them step by step.

1. Beams and wheel support

On each side, we need beams on both sides of the wheels. This is because a shaft spins smoothly only when it is supported in parallel on the same horizontal level. If the wheels are left on the outside without proper support, they can be damaged or fall off, and the wheels and gears will rub against the frame, creating friction instead of spinning freely.

2. Wheels and gears

Always make sure gears are firmly secured so they don’t slide during practice. For example, locking a gear with a fixed beam is usually more reliable than only using a rubber shaft collar.

For the wheels, it is recommended to fill up the empty side of it. Adding a 2x2 beam can provide another hole for supporting the wheel in place. By doing so, even if one side of the hole was damaged, the wheel could still spin nicely. This could also reduce the amount of spacers used.

3. Chassis Length

As an example, let’s consider a common 1:2 gear ratio. Since the wheels are spaced apart, you usually need more than three gears to bridge the gap—about five is common. Once you line up the wheels and gears, you can decide on the best beam length, making sure it’s long enough to fit corner connectors while still leaving room for the wheels.

4. Chassis width

The width depends on how you connect the two sides. Most teams use corner connectors, which can be arranged in multiple ways. Moreover, using corner connectors also helps in connecting the two sides together. In general, you want the chassis as narrow as possible so it doesn’t waste space needed for subsystems on top.

The overall width depends on your robot design; you could always adjust it.

5. Motor placement

Motor position also depends on the robot’s design. If you need systems in the front, place the drive motors in the back to free up space, and vice versa. Motor shafts are recommended for motor connections, obviously. It can make sure the shaft won't fall outwards.

Remember, the example I showed is only one possible setup. It’s not the only or best option. Use these tips and experiment with different configurations to see what fits your design needs. To give you some ideas, there are many possible ways to build a 1:2 gear ratio chassis. Don’t be afraid to try out different versions yourself.

That's it for this episode. This is IntroVex, your robotics guide to VEXcellence. See you in the next article or video!!

【EP2】【VEXIQ】Build Your Chassis!! – The difference between sprockets, gears, and pulleys

Hello! Welcome back to IntroVex, your robotics guide to Vexcellence.

In our last episode of Build Your Chassis, we talked about the fundamentals of gear ratios and the common ones found in a competition. This time, we will explore ways to create ratios beyond solely relying on gears.

Overall, there are three common ways to create ratios between the input and output while transferring the power from one location to another: Gears, Sprockets, and Pulleys. Later on, we will discuss the PROS and CONS of each and when is best to use them.

Gears

First, let's talk about the gears. Gears in VEX IQ come in different sizes, starting from 12-tooth gears up to 60-tooth gears. All gears are multiples of the 12-tooth gear, including a 24-tooth, 36-tooth, 48-tooth, and 60-tooth gear. Among these, the odd multiples of a 12-tooth gear can line up in a straight line together, while it forms a diagonal slope when one odd multiple connects with an even multiple tooth gear.

When two gears are connected together, they spin in opposite directions. Similarly, when three gears are connected together, the first and the third gear spins in the same direction. Overall, if the number of gears connected is even, the first and last gear spin in opposite directions; vice versa.

Sprockets

Next, let's talk about sprockets. Sprockets are shaped similarly to gears but with the teeth wider apart, and are connected through linked chains instead of connecting them side by side. Sprockets are sized from the smallest 8-tooth sprocket to the largest 40-tooth sprocket. You may also notice, all the sprocket sizes are multiples of the 8-tooth sprocket, including 16-tooth, 24-tooth, 32-tooth, and 40-tooth.

Since sprockets are connected through chains, the motion of all connected sprockets in the same chain spins in the same direction as the input. Also, there is never a limit on how you connect the sprockets. All can be connected as long as the chains can reach both ends while being straight.

Pulleys

Finally, let's introduce pulleys. Pulleys have no teeth like the others, but rather, it is connected through rubber belts just like how it appears in physics textbooks. Additionally, there are only 4 sizes of the pulley: 10mm, 20mm, 30mm, and 40mm (in perimeter).

Similar to sprockets but different from gears, the connection of pulleys requires a belt, which results in all pulleys connected together spinning in the same direction.

Comparison between Gears, Sprockets, and Pulleys

After the brief introductions, let's talk about when you can use the three connection methods as well as their advantages and disadvantages.

Gears:

PROS:

• Powers can transfer flawlessly and directly from the input to the output
• Doesn't have to worry about belts or chains falling off

CONS:

• There are restrictions on possible connections. You might not be able to reach a certain gear ratio with the correct direction of spin with a fixed amount of distance between the input and output.

Sprockets:

PROS:

• Can connect from any location to another
• Can easily switch up the sprockets to reach other ratios
• Can connect multiple outputs to one input easily

CONS:

• Chains may break upon collision or aging
• Need to adjust the length and tension of the chain when connecting

Pulleys:

PROS:

• The sizes are relatively smaller than sprockets and gears

CONS:

• The pulleys may slip easily when rubber belts don't provide enough friction
• Rubber belts are fixed in length, may not find the perfect belt to connect a certain distance
• Cannot connect locations that are too far away

Simply saying, gears are really useful in places where you need precision in the turning, and the power transfer has to be consistent. One prominent example is the chassis. Even though sprockets can also do the job, gears can increase the actual motion transferred to the wheels and avoid the risk of repairing broken chains.

Sprockets, on the other hand, are great when connecting input and outputs that are far apart and not lining up straight. If you tried using gears to connect and found that you cannot possibly reach the destination with the preferred gear ratio and number of gears, it may be best to switch to sprockets and try again.

Pulleys, finally, are uhmm... not really good at anything. First of all, the rubber belts can really slip easily, especially when you want to turn something heavy and requires torque, pulleys may fail the job. One of the better and common usages of the pulleys is using them as side wheels that guide the mechanism or robot smoothly.

Possible Combinations and Applications

After all the explanations, you may think that gears are gears and sprockets are sprockets, which they are, just separate things to consider when constructing. However, this is not always true. Sometimes, you may need two things spinning in different directions, but the distance won't fit an even number of gears with the gear size you prefer. This is the time to combine the two.

Take an example of the side rollers we made in the current VEX V5 Push Back season. The space at the time was 7 holes in between the two rollers, but after simple attempts, we found that we could not find the perfect combination to get a 1:2 gear ratio with an EVEN number of gears. At last, we figured that we could use an even number of gears to power one roller while using sprockets and chains to power another, making the rollers spin in opposite directions.

Aside from this example, there will definitely be more cases, but I am just here to remind you that sometimes thinking outside the box and combining different things can help you find the solution.

【EP1】【VEXIQ】Build Your Chassis!! – Comparing Common Competition Gear Ratios

Hello! Welcome back to IntroVex, your robotics guide to Vexcellence.

In our new series: Build Your Chassis!!, we will talk about key ideas that might help you build a sturdy and smooth chassis for your robot. A robot needs a chassis with wheels that spin smoothly and as frictionless as possible to run fast at its intended speed. We'll cover some simple yet handy tips for you to improve.

In this episode, we will first talk about the common gear ratios of competition robots. Gear ratio is a key factor you have to decide based on the characteristic you want your robot to have, commonly between high speed and high torque.

How to calculate Gear Ratio?

At first, when you built your first robot using the VEX IQ super kit, competition kit, and education kit, you will most likely connect the wheel's shaft directly to the motor's shaft. This either makes one of the wheels not connected to motor power, or it connects two wheels with gears to make the power transfer to both wheels.

In the two cases, the latter (connecting wheels with gears) performs better because there wouldn't be one wheel that only provides friction resistance and does not contribute to forward motion. Taking the first-generation starter kit clawbot for example, even though the shaft of the wheel is still connected directly to the motor, the 36-tooth gears bring rotational motion to the second wheel as well.

However, in both cases, they barely covered the gear ratio idea used in competition robots. In competition chassis, we often make the chassis longer. Additionally, we alter the size of gears connected to generate faster or slower speeds; this is called the Gear Ratio.

Gear Ratio is a "ratio", obviously, but between what two values? We have to take into account the "input gear" and the "output gear". The input gear is the one that is directly spun by the motor, and the output gear is the one being driven. Regarding the clawbot, the 36-tooth gear connected to the motor serves as the input gear, and the final gear at the end is the output gear. 

What does the middle one do? You may ask. The middle gear in this case is an idle gear that doesn't affect the final gear ratio, meaning we can change the middle gear into 84T, yet the two wheels still spin at the same rate.

Next, the Gear Ratio is calculated by dividing the output gear tooth by the input gear tooth. Please make sure you don't get it the opposite way because they can mean very different things. In the clawbot case, the gear ratio will be 36:36 = 1:1.

Looking at another case, why not try to identify the input, idle, and output gear, then calculate the gear ratio by yourself? The answer will be at the end of this blog.

Common Gear Ratio Used?

The common Gear Ratios in VEX IQ are normally used for increasing speed, in other words, a lower gear ratio. For example, the most common ones are 1:2, 1:1.5, and 1:1, and two of them are for increasing speed, while the other doesn't change speed.

In super kits, there are only three sizes of gears included: 60T, 36T, and 12T. If you do a little calculation, it is impossible to create the above 1:2 and 1:1.5 gear ratios using only the three sizes. Additionally, 60T cannot be used in a chassis as it has a greater diameter than most commonly used 200mm travel wheels (Note: 200mm is the perimeter, so the radius is about 3.183cm).

If you want to connect wheels and motors through gears, you will have to purchase the gear add-on pack containing 24T and 48T gears. You'll have to use sprockets or pullies, which we will talk about in our next episode. 

With 24:48 or 12:24, we can generate a 1:2 gear ratio, making the wheel spin twice as fast as the motor's rotation. However, 12:24 is not recommended in this case because both gears are too small, and you'll have to use additional gears to separate the wheels, like the picture indicates.

Moving on to 1:1.5 gear ratio, it can only be accomplished with 24:36. This might require some more complicated connection method since the wheel covers the center of the 36T gear when aligning both gears side by side with 24T attached to the wheel (shown above).

An example of a 1:1.5 gear ratio is my chassis during slapshot season. As you can see above.

A 1:1 gear ratio can be achieved by any type of gears if the output and input gears have the same number of teeth.

An additional gear ratio possibility is 1:1.3333, using 36:48 gears. This provides a little more speed while not altering the motor torque that much.

What's the difference between these Gear Ratios?

Now, I am here to answer the question of "What's the difference between the gear ratios?". Aside from changing the output speed, it also changes the output torque, which is inversely proportional to the change in the output speed.

Let's use the gear ratios we talked about as an example to calculate the speed and the torque of the chassis. Before calculating, we have to acknowledge that the VEX IQ smart motor spins at 120 RPM and has a stall-torque of 0.414Nm (Nm=Newton Meter), meaning the motor can resist 0.414 Newton of force at a distance of 1 meter. 

When we use a gear ratio less than one, the speed is multiplied by 1/gear ratio, which increases, but the output torque is multiplied by gear ratio, which decreases. An easier way to think about the relationship between speed and torque without calculation, the larger the motor gear is than the wheel gear, the higher the speed and the lower the torque. 

Next, we can list out all the gear ratios and their input and output gears like above, then proceed to speed and torque calculation.

After filling in the calculated speed and torque, we can observe the fact that all speed*torque equals the original speed*torque, which is evident from the fact that both have an inversely proportional relationship.

"Speed difference can be observed, but what does torque do?" you may ask. Torque determines the maximum weight the chassis can handle before the motors stall. If your robot is too heavy or faces too much resistance, and your motor torque isn’t enough to handle it, the robot will slow down or may not move at all. We'll dive into the detailed calculation in the future, but for now, just remember: higher speed isn't always the best; you have to consider how much structure you'll put on the chassis.

Conclusion

If you know that you need to run around the field fast and don't have to carry a lot of game elements, you could try a lower gear ratio, like 1:2 first. However, if you need a complex structure like the full volume season robots, you might want to consider higher gear ratios than 1:2, or else you might carry weight heavier than intended and actually make your robot go slower than 1:1.5 gear ratio robots.

Feel free to experiment with different gear ratio combos and connection methods on your chassis!! Also, the answer to the gear ratio above is 4:1, with the 48T gear being the output gear and the 12T gear being the input!! Others are all idle gears.

In our next episode, we will talk more about sprockets and pulleys and how they differ from gears. Just a note, the two can also be used in chassis sometimes!! Also, we'll look at how they are used to connect chassis.

This is IntroVex, your robotics guide to VEXcellence. See you next time!!

【Interview】What 7 Years in VEX Taught Me – Andrew

Hello! Welcome back to IntroVex, your robotics guide to VEXcellence.

Every competitor in VEX has their own unique journey. Their experience in growth, learning, and failure is also irreplaceable. Have you ever wondered what the VEX players near you experienced that navigated them through competitions and made them what they are now?

In this interview, we are joined by someone who has participated in VEX competitions for 7 years. He is Andrew, a competitor from Taiwan. He participated in 5 years of VEX IQ and 2 years in VEX V5, while one of his greatest achievements was securing the teamwork world champion as well as the excellence award during the Live Remote World Championship in 2021-2022 Pitching In season. Let's hear what he has learned along the way!!

About Andrew

What roles have you taken on in your team, and which do you like best?

Andrew: "I’ve done everything, including driving, building, programming, and engineering notebooks. My favorite is driving because with every round of practice, I can feel myself improving, and reaching milestones gives me a real sense of accomplishment."

There are many kinds of roles that need people to complete and take on responsibility, but not everyone can determine their role when they first join VEX. It takes time for you to try different ones to find your favorite and to find the one you are good at. In the 7 years, Andrew tried everything and found that driving was his favorite. Aside from driving, we can also see from his achievements that he studied robot structures and programming deeply as well.

When did you first join VEX? Why did you start?

Andrew: "My first season was 2018–2019, Next Level. My parents bought a basic kit to let me try it out. I didn’t really feel much accomplishment at first, and kept going kind of half-heartedly. But over time, I found it more and more interesting, and I’ve been doing it ever since." 

Out of all VEX participants, there must be some who didn't start learning robotics to compete in VEX competitions but got attracted to it and continued to play. Indeed, I am one of them. I started going to robotics classes just to learn the new technology trend, but at last I got interested in competing and continued doing so until now. That is why I would suggest, instead of trying to make a decision in your head, trying a little at first to decide whether to compete or not would be the better option.

Learning Process

What kinds of difficulties did you encounter in your learning process?

Andrew: "When it came to learning programming and building, the resources felt limited and hard to find. Maybe they were out there, but most were in English, so I couldn’t understand much. And often they didn’t really get to the point."

Sometimes the online tutorials are made by experienced teachers or students, but they might accidentally miss some basic concepts that may seem obvious while actually being difficult for beginners to understand. It isn't easy to create tutorials that cover both difficult and fundamental concepts at once. IntroVex will work hard to cover the basic concepts and try to convey knowledge to everyone!!

What was the hardest problem you encountered? How did you solve it?

Andrew: "It was during the Skills Challenge. My robot’s autonomous program wasn’t moving steadily, so I looked up videos on PID control to learn how to fix it."

What kind of video or help would’ve made things easier at the time?

Andrew: "I only found one video from a foreign team explaining P control step-by-step. If there were more detailed tutorials, especially in Chinese, that would’ve helped a lot."

Since English-speaking teams are the majority of the teams that participate in VEX, many online tutorials are created in English. However, since Taiwanese teams often understand Mandarin better, IntroVex will try to cover some important or complex topics in both languages to reach out and help more teams. Also, subtitles can be found on YouTube and can be translated into many other languages as well.

Advice for New Competitors

What advice would you give to someone new to VEX?

Andrew: "Choosing teammates is really important. Instead of just picking close friends, it’s better to find people who are passionate about VEX and willing to work hard. If you're just doing it for fun, that’s fine, but if you want to be serious about competing, choose wisely." 

That's right!! Team composition is a very important factor to consider!! If every team member has similar goals and is willing to cooperate with each other on different aspects, naturally, a good team could be formed. This is why taking your time to find teammates is an important step before the season starts!!

What’s something you wish you knew in your first year?

Andrew: "I wish I had divided the work better and trusted my teammates more. Of course, I could still keep learning myself, but I didn’t need to do everything alone. If you do too much on your own, your teammates don’t improve, and then later, you won’t feel comfortable letting them take over. It becomes a cycle, and in the end, you’re competing alone."

This experience delivers the importance of allocating roles within a team. If someone in your team takes on the role of allocating jobs for each person, with correct cooperation and trust, the team would be able to grow and learn together from successes and failures. However, it isn't an easy task if you just joined the competition recently. This year, I am also trying to accomplish this by understanding more about my teammates and trusting them in the process of trying.

What’s the biggest thing VEX has taught you over the past 7 years?

Andrew: "It’s definitely expanded my perspective. If I hadn’t done robotics, I probably would’ve only known people from Yilan. But because of VEX, I’ve met all kinds of people. One time at a tournament in Taipei American School, I got to connect with students from different regions — it was a great experience."

I agree with Andrew's response. Participating in VEX allows you to meet people from different backgrounds, different cities, and with different ideas, and this is the biggest thing VEX can bring you. It doesn't matter if you are an introvert or an extrovert; you will definitely make friends along the way. You might start by connecting with people from your lab, club, or city, but eventually you'll meet other teams during competitions. I would definitely recommend you to devout time to make connections with people during competitions aside from competing. 

That's it for this interview. I really hope this helps you on your VEX journey by understanding what VEX can bring to you. I am really thankful to Andrew for partaking in this interview and sharing his experience over the years. 

This is IntroVex, your robotics guide to VEXcellence. See you in the next article or video!!

【訪問】七年的 VEX 經驗教會我什麼？一 資深選手 Andrew

歡迎回到 IntroVex，陪你邁向 VEXcellence 的機器人指南！

每一位 VEX 選手的旅程皆不一樣，每一位選手在比賽過程中的體會、成長、挫折等等的經歷都是獨一無二的，每一位選手的參賽時長更是不相同。你是否曾經好奇身邊的選手們經歷過怎麼樣的學習才造就現在的他們呢？

這次的訪問，我尋找到一位參加 VEX 比賽總共 7 年的選手一Andrew。這位來自宜蘭的選手，從 2018 至 2019 的 Next Level 賽季開始參賽，至今累積了許多參賽經驗，而他最亮眼的成績是在 2021-2022 Pitching In 賽季的線上 LRT 世界賽當中獲得團隊挑戰賽冠軍以及全能總冠軍。讓我們透過訪問，了解他對於 VEX 的想法以及在 7 年經驗中的收穫吧！

關於 Andrew

在你所參加過的賽季當中，有負責過哪些工作？最喜歡的是？為什麼？

「全部都有，遙控、組裝、程式、工程筆記都有。這些當中最喜歡的是遙控，因為可以在一遍又一遍的練習中不斷成長，當達到一個段落後會有很大的成就感」 Andrew 說。

其實比賽當中有很多不同種類的工作需要有人負責，但剛開始加入的時候，並不是每個人都能夠迅速地尋找到適合自己的工作。在這 7 年的時間，他透過嘗試每一種工作找到了自己最喜歡的「遙控」。不過他也在其他工作中掌握到訣竅並持續鑽研，這幾年的比賽中都能夠看到他在結構和程式上努力的足跡。

你所參加的第一個賽季是？為什麼會想接觸 VEX 呢？

「2018-2019 Next Level」Andrew 說，「當時父母準備一套基本款讓我嘗試，第一次打比賽沒什麼成就感，之後有點半推半就的打下去，結果越打越有興趣就打到現在了 。」

在所有參賽選手當中，必定會有些人剛開始接觸時其實並沒有明確的目標或目的，但開始嘗試後卻被 VEX 有趣的地方吸引並持續下去。其實我也是這樣的，剛開始只是去上課並嘗試新的活動，但實際上我卻發掘了自己的好勝心，並繼續持續參賽。若你正在苦惱是否要參賽，可以考慮先嘗試一段時間後再做出決定喔！

學習過程

在學習和資源方面，有沒有遇到找不到方向或資訊不足的情況呢？

「學習程式以及組裝上的資源其實都感覺很少，不好找，應該說可能有但大多是英文，所以也看不太懂」Andrew 說。他也強調「時常有些地方感覺沒有講到點上 」。

有時網路上的教學影片是由經驗豐富的選手或老師所製作，而時常會漏掉一些看似理所當然但其實剛加入的選手在理解上會有困難的知識。要如何製作第一年參賽的選手也能輕鬆看懂的教學影片並不容易，IntroVex 也會努力將基礎的概念都完整傳達給各位的！

你遇到過困擾你最久的問題是什麼？那時是怎麼處理的？

 「技能挑戰賽的自動，當初為了解決移動不穩的問題上網找了 PID 控制相關的影片學習」

承上，你覺得怎麼樣的資源(或影片內容)能夠幫助當時的你？

「當初我上網找可以手把手教學的只有一部外國賽隊的 P 控制的影片而已，如果可以有中文或是更詳細的教學就會更好」Andrew 說。

由於外國隊伍比例上較多，網路上較多教學影片是使用英文介紹。在 IntroVex，即便大多的影片內容為英文，每一支影片都會提供中文字幕的選項。在接收到 Andrew 的建議後，IntroVex 之後在介紹較複雜的概念時也會出兩個語言的影片的！

給予新同學的建議

如果要給剛開始參加 VEX 的同學一個(或多個)建議，你會說什麼？

「隊友的選擇很重要。」Andrew 說。他也強調：「比起找熟人，找對 VEX 有熱情並願意付出努力的隊員可能更好。除非是休閒打，如果想要認真打比賽還是要謹慎思考隊友。」

隊伍的組成是非常重要的考量！若每一位隊員都有相同的目標，而且在工作分配上都能互相配合、努力，自然就能夠組成一支不錯的隊伍。在賽季開始之前，尋找適合的隊員也是非常重要的呢！

經歷過 7 年的 VEX 比賽，有沒有什麼是你現在已經學會、但希望當初第一年就懂的事情？

「希望當初我可以分配不同工作給隊友，當然我還是可以學習，只是不要放不下心就都自己來。」Andrew 說。他也進一步說明：「如果可以的話盡量讓隊友可以跟你一起成長，如果當下你選擇自己多努力一點，當然你自身能力會更強，不過相對你的隊友也就無法進步。這會導致之後你很有可能會放不下心讓隊友去做，如此反覆循環下的結果就是最後就變你一個人在打比賽了。」

這樣的經驗也告訴我們團隊中工作分配的重要性。隊伍中若有一位隊長能夠發掘各隊員的長處並妥善分配工作，配合團隊默契和隊友間彼此的信任，才能促使團隊一起成長、一起學習。不過在自己也不完全了解比賽內容時，要做出這樣的決定不容易。今年我在團隊當中也希望能夠分配更多工作給每一位隊員嘗試，也會在 IntroVex 當中將自己的知識傳達給大家！

你覺得這 7 年的 VEX 旅程當中，收穫最多的是什麼呢？

「我覺得對我來說最大的收穫應該是擴大我的視野。」Andrew 說。他也分享：「如果不是有打機器人，我認識的人應該都侷限在宜蘭而已。但因為有打機器人，我可以認識各式各樣的人。之前有一次在台北美國學校參加比賽時，有認識一些人，可以跟不同地區的人交流很不錯。」

我也同意 Andrew 的說法，參加 VEX 最大的收穫之一就是認識不同背景、不同城市、不同想法的人。不管是較內向或外向的人，在 VEX 的旅程當中，一定會結交不同的朋友，可能從相同教室或隊伍的成員開始，但慢慢的也會在比賽中認識不同縣市的隊伍成員。希望大家在比賽當中，除了專注於取勝之外，也可以多去和不同隊伍聊聊天！

希望大家透過這次的訪問能夠更了解 VEX 帶給選手的影響，也許能夠幫助正在了解此賽事的人在決定上更果斷！真的很感謝 Andrew 選手願意接受簡短的訪問，也希望他的經歷能夠幫助到正在經歷 VEX 各種時期的選手們。

這是 IntroVex，陪你邁向 VEXcellence 的機器人指南！我們下一篇文章見！

The subsystems of a robot - Robot Design Introduction

Hello! Welcome back to IntroVex, your robotics guide to VEXcellence.

We compared the differences between VEX IQ and V5 competition designs and overviews in previous episodes. Starting from now, we will start including some "robotics" ideas for the competition, such as constructing a robot and programming. If you are someone who struggled during robot preparation, maybe this is the kind of article you're looking for!

This time we'll be discussing what makes up a robot and talk about common aspects of a robot. You may often see a robot as one big system/structure, but they are often constructed of different subsystems. Knowing the types of subsystems often incorporated in robots can benefit you during both the brainstorming and construction stages, meaning you don't have to think and build the whole robot in one go. Rather, you can think about each subsystem one by one, and then finally combine them into a robot.

The common subsystems include the following: Chassis(Drivetrain), Intake, Scorer, End Game Mechanism, and other subsystems based on the year's game.

Chassis / Drivetrain

The chassis, also known as the drivetrain, is the base of a robot. This subsystem is usually the one you start with because the structure of your base will decide how to cooperate with other subsystems.

One of the most important aspects of deciding on the drivetrain is the gear ratio. Gear ratio is the ratio between the gear driven by your motors to the gears driving your wheels. If you have a higher gear ratio, meaning you use a larger gear on your motor than the wheels, your robot will have a faster speed. Oppositely, if you have a smaller gear ratio, your chassis will run slower but have more torque.

Simply put, use a higher gear ratio when the game requires fast movement speed, but use a lower gear ratio when your robot is heavy and big, as a fast drivetrain with a heavy top will make the overall speed even slower.

Another important aspect to consider is the number of motors and wheels you use. Motor usage may have to be considered alongside other subsystems. If there are many missions to complete on the field, you might have little motor usage available left.

For VEX IQ, the number of motors used on the chassis usually goes around 2-4, since the motor limit is 6. For VEX V5, the number of motors used is usually 4-8. The VEX V5 game gives you more space for creativity, so there might be a robot using all 8 motors on the chassis, and using PTO or pneumatics for other functions.

Intake

The intake is the subsystem used for picking up the game object, for example, balls or blocks. Usually, intakes are constructed with wheels or rubberband rollers, but some intake designs can also be plowers or claws that also show the ability to hold onto the game object.

If the game object is a round object like a ball or the triball in over under season, using a wheel or rubberband roller is common and simpler. Some special intakes include the hero bot for this year's VEX V5 game, High Stakes. It uses a passive ring grabber to hold onto the ring and pushes it out with a motorized mechanism. A More detailed explanation can be found in VEX's official YouTube introduction above.

Scorer

Next, a scorer is often the subsystem used to score the game object. For example, for shooting a ball into the goal, or putting rings onto a game element. The scorer doesn't have to be a shooting structure, it can be a conveyor belt like this year's High Stakes V5 game, or the elevator used in VEX IQ Full Volume.

Depending on the game, scorers can have tons of designs, and they usually keep evolving as the season progresses. One of the most common scorers is shooting mechanisms, exemplified in Pitching-In, Slap Shot, Over Under, and this year's VEX IQ game, Rapid Relay.

Common types of shooters include flywheel, puncher, and catapult. Flywheel uses one or two wheels and shoots out the game object straight by sliding it between the wheels that spin super fast. Puncher uses a linear moving stick to hit out objects through a straight line, like how I designed the shooter during Slap Shot. A catapult is a mechanism that first drops to the lowest point, and then shoots out the object by sudden release, creating a parabola when the object is sent flying.

Sometimes, scorers are combined with intakes, like the Rise-Above season where we use claws to stake game objects, so don't limit yourself to these categories. Finding the most creative and useful solution is most important when designing your robot.

End Game Mechanism

Some games include end games like elevation or touching something, and the end game mechanism is for this. Since how the end-game scoring is done varies in every game, it is hard to state what one will look like, but you may get a sense of it by some examples.

During the Pitching In season, we had to elevate from the ground. The low elevation is often done with passive mechanisms by running the robot onto the stick for elevation, same with Over Under's low elevation. High elevation requires some creativity, and it depends on the stick for you to climb. In Pitching In, we had a wall to support our robot and a horizontal stick to grab onto, so we used a 4 bar lift structure to climb. However, elevations in this year's High Stake provide only horizontal sticks and not a wall, so the hanging structure will be more complicated.

Other mechanisms

Some other mechanisms may include supporting hooks or hands to push away game elements and stuff, it can be moved using a motor or pneumatics.

An example is the wing used to push triballs during Over Under, which functioned through pneumatics. Another example is the robot guide used to touch both sides of the walls in Rapid Relay, it doesn't have motors nor pneumatics for movement, but it is an important subsystem to have for particular strategies.

These are more game-specific, and teams often develop their own, so it is not much for generalization.

This is about all for the subsystems of a robot. I will continue to introduce different subsystems in detail in the future. If you like this type of content, please let me know!

This is IntroVex, your robotics guide to VEXcellence, see you next time! Bye~!!

What's the difference? VEX IQ vs VEX V5 - EP2 Competition / Match Design

Hello! Welcome back to IntroVex, your robotics guide to VEXcellence. 

This is the second episode of the "What's the difference? VEX IQ vs VEX V5" series, and we will discuss the differences in competition and match design. If you are willing to understand both competitions or if you are just about to transition from IQ to V5, this episode might be worth watching!

Match Design

The first major difference is how teams partake in one match. In VEX IQ, two teams will work together and try to score the highest score they can. Basically, VEX IQ matches are more cooperative, making communications on strategy beforehand super important.

Each match of VEX IQ has a time length of 1 minute. There will be a required driver switch during the 25-second and 35-second period, which simply means the controller should be given to another driver on your team.

On the other hand, VEX V5 requires four teams to participate in a single match. Two teams form an alliance, each naming the blue and red alliance, and the two teams have to battle to see which side scores higher at the end of the match. Both cooperation and competition are present, making the ability to think of a counter strategy immediately during a match crucial, as it is impossible to predict every step before the match.

Another point about VEX V5 communication is the addition of autonomous routes. Since there is a 15-second autonomous period at the start of a match, discussions about autonomous distribution are required. The total match time is 2 minutes, with 15 seconds of autonomous and 1 minute and 45 seconds of driving, no driver switch required.

Overall, match communication may be more complicated for VEX V5 competitions, but VEX IQ still requires active thinking and discussion about strategies with alliance teams.

Qualification Rankings

Next, we will compare the differences of how qualification rankings are evaluated based on the result of each of your matches.

For VEX IQ, it is quite straightforward. The qualification ranking will be filtered from high to low, based on your average qualification match score, with one lowest-scored match deleted every 4 matches. 

For example, if I competed 6 qualification matches in total with the following scores: 100/50/30/80/90/70, the lowest match score of 30 will be deleted, making the score average of 78. The teams with a higher average score than 78 will be in a higher ranking, vice versa. If there are ties between two teams in the rankings, it will be broken through comparison between the new average score with another lowest score deleted, and so on.

For VEX V5, it is a bit more complicated. There are three values evaluated after the match ends, which are Win Points (WP), Autonomous Points (AP), and Strength of Schedule Points (SP).

Win point is the score that is first compared in rankings. If your alliance won the match, both teams will get 2 win points, and the losing alliance gets 0 win points. You will get 1 win point if the match is tied, or if you finished the tasks required for autonomous win point during the 15 seconds of autonomous.

For example, a team can get the highest win point of 3 points after each match if they won and also finished the autonomous tasks. A team can also still secure a point from autonomous even if they lost. So, autonomous win point is super important. Normally, the counts of points are used, but the average win point will be used during league competitions where not all teams played the same number of matches.

Autonomous Point will be awarded to the winning alliance of the autonomous period (the one who scored higher during the first 15 seconds). Each season has a different score awarded. For example, the over-under season awards 8 points to winners and 4 for each team when tied. While the High Stakes this year awards 6 for winners and 3 for tied situations. This will be compared if two teams had win points tied.

Strength of Schedule Points is the score of the losing alliance in a qualification match. This is the third basis for ranking if the above two tied within teams. For example, if a match ended with 60 to 30 with the blue alliance winning, all four teams will receive the SP of 30 points.

Overall, V5 has a much more complicated ranking system. Even though it may be difficult to understand, it is important to at least have a brief understanding of them to know what to prioritize in a competition.

Final Matches

Next, let's talk about alliance selection! There is actually a big difference between how the final alliances are decided between VEX IQ and VEX V5, and is one of the biggest "cultural shock" I experienced in my first year V5.

For VEX IQ, the final alliance is decided by the qualification ranking. The first and second ranked Teams form an Alliance, and go on until no more alliance can be formed. This means if the total participating teams has an odd number, there will be one ineligible team to partake in the finals. Simply saying, you cannot choose your alliance in VEX IQ, and your qualification ranking is crucial to your survival in final matches.

If the first place is tied, a tiebreaker round is required. When I was in the Pitching-In VEX IQ worlds, we and another alliance tied with full score, and we had to play again to enter the dome. Luckily we played consistently as how we practiced and moved on.

For VEX V5, even though the qualification ranking also plays a role, teams got to choose their alliance, making the ranking not as decisive. The alliance selection starts from the first ranked team selecting their alliance, the selected team can either accept or reject the offer. Once a team rejected a selection, they can only wait until their time to choose another team and cannot be chosen again. Simply saying, a team can only be invited once to an alliance.

There is not an unlimited amount of final matches, only 16 alliances can be formed at most for VEX V5, and the final match schedule will differ based on the number of alliances formed. For example, if only 12 alliances were formed, the first four alliances formed will advance to the quarter finals immediately.

Also, for all elimination matches, only one match will be played to determine the advancing alliance. However, for the last game of all final matches, where it determines the first and second place, will have to play a "Best of 3" game if the event is world qualifying or multidivisional. For smaller non-qualifying events, still only one match will be played for the finals' final match.

Skills Challenge

There are no major differences in skills challenge, both VEX IQ and VEX V5 have a skills match time of 1 minute, and each team gets 3 attempts on both driving skills and autonomous skills.

That's about all of the differences between the competition of VEX IQ and V5. If you have any questions about other aspects of the competition, feel free to comment and submit what you would like to know more about!!

This is IntroVex, your robotics guide to VEXcellence, see you next time!!

What's the difference? VEX IQ vs VEX V5 - EP1 General/Preparation

During previous articles and videos, we talked about an overview of VEX competition seasons and competitions. This time I will be introducing the differences between two main VEX competition categories, VEX IQ and VEX V5. There are other competition categories aside from the two under REC foundation, but we will not talk about those. You can search it up if you’re interested.

This is the first episode of the series, and there will be more comparisons out in the future!!

Age Distribution

First, there is an age difference between the participants for the two categories. VEX IQ has an Elementary school and middle school division, while VEX V5 has a middle school and high school division. If you are deciding on which competition to join, you can use these as a reference, but you can also attend divisions that are higher than your current grade.

The category you should compete in is obvious for elementary and high school students. However, for middle school students, I recommend starting with the one you’re most interested in. If you want to challenge yourself and have a lot of time to practice, I would definitely recommend VEX V5. Don’t worry about starting with zero knowledge of robotics; everything can be learned afterwards if you have the passion and dedication.

Team Composition

One major difference is in the team composition. Since VEX IQ has a simpler game design and robot parts, it doesn’t require as many team members as VEX V5 teams. A Vex IQ team usually contains around 2 to 4 members, while VEX V5 teams may go from 2 up to 6 or even more team members.

This difference is mainly due to the more complicated and time-consuming work that VEX V5 teams must perform during the robot construction and competition preparation process.

Time Consumption 

From my experience, VEX V5 takes significantly more time than VEX IQ. Your robot building time extends from about one week of construction in VEX IQ to about one month of construction in VEX V5. Furthermore, the time you will have to put in practices regarding driving and programming would increase due to the difference in match designs.

According to my own experience, if you have a busy testing schedule at school or you focus on your study more, I recommend taking one year off VEX V5 or else you might not be able to balance work and competition.

Robot Construction

VEX IQ robotics parts contain flat plastic beams that are connected together through plastic pins. Other plastic parts also have the same thickness as the beams. Connections between parts are easy to undo just by pulling the beams apart, making the construction process fast.

VEX V5 robotics parts are more diverse, with different types of channels with diverse shapes. The connections are done through screwing vex screws and nuts. The construction and separation of a robot would be so much more time-consuming because connection is not as easy to break as with pins.

More detailed comparison between VEX IQ and VEX V5 parts will be done in the future.

Programming

In VEX IQ coding, we usually go with VEXcode IQ to program. However, in VEX v5, tons of coding platforms work well at programming and are not restricted to the VEXcode systems. The structure of the whole project is also much more complicated, along with more sensors added to the robot.

Overall, I would say VEX V5 is a much more complicated game and requires a lot more effort and time. However, if you are willing to accept all the challenges along the way, you will definitely enjoy V5 as the season progresses.

I hope this article helps explain the differences between the two competitions. In the next article, I will discuss the differences in Competition and match design. Stay tuned!

What To Expect In a VEX Competition? - Competition Overview

Hello! Welcome back to IntroVex, your robotics guide to VEXcellence.

Last time, we discussed the events that occur during a VEX competition season. This time, I will introduce the competition schedule, which you will most likely encounter multiple times during the season.

Competition Timeline

A competition can last from one to three days depending on the number of teams and the significance of the event. For example, a smaller regional event with no qualifying awards may last only one day, but a national world-qualifying competition may last three days.

During the day of the competition, the schedule most likely starts early in the morning and ends in the afternoon. The most common schedule I have experienced is from 8am to 5pm.

A lot of events happen throughout the day, including main competitions, skills challenges, inspections, interviews, and many more in which teams have to participate. Moving on, I will introduce these one by one.

Check-In / Inspection

The first thing you encounter in the morning after you arrive is the Check-In and Inspection process. This only occurs during the first day of the competition. Although the two are completely different events, they are often combined and executed at similar times.

Check-in is when teams complete their identity checks with the event partners, ensuring that the people entering the competition are participants and not unrelated individuals. You might have to show your ID to the event staff. If verified, you'll receive a nameplate that has your team number or your name written on it.

Remember, some events require you to always wear the nametag when going to competitions or practices. If it is specifically mentioned, please make sure not to lose it. However, some competitions would skip the check-in process if there are too many teams or it is just not required.

Inspection is when teams bring their robot and controller to perform size checks and other verifications. This is to make sure no rule-violating robot appears on the field, making the competition fair. The process is usually executed by referees who will be paying attention to violations during a match.

The referees may ask questions about your robot, including but not limited to the number of motors used, whether the firmware is up to date, and how your robot extends. The robot inspection follows a list that can be found on the official VEX website, make sure to check the newest version before going to the competition.

You'll have to pass the robot inspection before practicing or competing, so it is very important to check your robot size and other aspects the day before the competition. You'll feel devastated if you have to fix your robot because you failed inspection multiple times while the other teams are already practicing, but if that really happened, just calm down and think of solutions to fix and you'll be fine.

Drivers Meeting

Before starting any match, there will usually be a meeting between referees and the participating team members as well as coaches. This process is to clarify the rules. The referee explains several example situations that often cause disputes and clearly states how the violation would be evaluated.

Students and coaches usually ask questions regarding specific situations. The referee would then explain the rule referenced and whether it would cause a violation. If you have any questions regarding the competition, feel free to ask the referees to confirm you are not violating any rules, the referees are always there to help you avoid violations.

Remember to pay attention to the meeting, including the questions asked by other teams. You'll be glad that you know how a close call is evaluated when you actually run into one. Better safe than sorry!

Skills Challenges

The skills challenge usually opens not long after the meeting and closes alongside with the end of the main matches. The skills challenge is where your team operates your robot and programs your robot to complete tasks by yourself. Your score will contribute to some decisions of the awards, so it is important to practice beforehand.

One team gets 3 attempts on both driver skills and autonomous skills. You'll have to score as high as you possibly can, and the final score of your skills would be the highest driver and autonomous skills score added together.

Skills challenges sometimes have different rules compared to the main teamwork/tournament matches, so make sure you understand the rules before attempting skills.

Qualification / Final Matches

The main matches in a competition are the qualification and final matches. Winning the final matches can often help you qualify for the subsequent event. The qualification matches are to help decide the awards as well as choose your alliance in the final matches.

You may play different amounts of qualification matches in different competitions. The competitions with more qualifying awards will usually have around 8 qualification matches per team, but smaller ones may only play around 6 matches.

Each match starts with a field check, the timer will then start to countdown. After your match, the referees will calculate the score and have you confirm it. Remember, you'll have to confirm the score carefully before giving a confirmed answer because you won't be able to change the score afterward.

As the qualification matches are played, the rankings of teams will also be updated based on your previous match results. Although the ranking is not a definite indicator of a team's ability, it is important in deciding your award and alliance, so it is better to get a higher ranking.

Award Ceremony

The competition ends with an award ceremony on the last day. Everyone takes multiple photos with their teammates, alliances, and friends, this is important because you'll definitely recall the exciting competition memory one day. It is better to have a photo than none.

The competition overview ends here!! More detailed explanations regarding the competition will be out in the future, so make sure to follow along! This is IntroVex, your robotics guide to VEXcellence, see you next time!

What To Expect In a VEX Competition Season?

Hello! Welcome to IntroVex, your robotics guide to VEXcellence. In this article, I will introduce what to expect in a VEX competition season using the example of my previous seasons in both VEX IQ and V5.

Timeline Overview

A complete robot season timeline would start from around June to May of next year, from the uploading of the current season's Game Manual to the next season's Game Manual.

A season is so long that a lot of events occur, and your photo album will be filled with pictures as well as videos of your robot runs. You may also meet a lot of new people along the way, which is the most exciting part of participating in robotics.

Starting in June, you will experience multiple robot construction cycles and improve your robot after each competition. At the end of February, you will know if you got the ticket to the VEX World Championship.

Next, I will talk about each section of the competition season in detail, follow along!! Please note that the following are based on my experience in Taiwan, it may differ in your country!

Robot Generation Cycle

The classroom buzzed with the clatter of tools and the whir of spinning wheels. Lively conversations and brainstorming sessions echoed throughout the room, creating a vibrant symphony of collaboration.

"Ah! It’s that time again—to design and test our new robot!"

Your first robot construction starts shortly after the release of the Game Manual, or it may start a bit later than this. You may be searching for inspiration, developing your prototype, or discussing with your teammates. The first robot may not be perfect, but it would give you insights on how to improve.

After the robot is built, programming is needed to test its functions. You may find a few, if not multiple problems with the robot. Here comes the most tiring part, solving a series of problems, but once you complete all of them, the sense of accomplishment is definitely going to be huge.

Competitions

The most important type of event in a competition season is a competition/tournament. These are times when you use the robot and program that you have prepared through the past few months to win awards for yourself. 

A season may contain from 1 to over 10 competitions based on your location, goals, and time. From my example, one season contains around 3 competitions nationwide. One of them being a Qualifier and one being Nationals which is the one that gives out world positions.

Competitions may last from a day up to three, depending on the number of teams participating. More details about competition agendas will be introduced in future content!😊

Final Destination: VEX Worlds

After your national competition, you will know very soon whether you got into Worlds or not. If you didn't get the ticket through your state competitions, you will still have the chance to be chosen through skill rankings if there are extra positions released.

VEX Worlds consists of three consecutive days and is in a significantly larger scope than you can imagine. There are hundreds of teams competing and you can get loads of souvenirs during the event. If you have the opportunity to go, please do so and try to enjoy the competition as much as you can!!

Conclusion

The VEX competition season is full of surprises and happiness along the way, but there are also times you might feel defeated by a complex problem from your robot or code. Ultimately, participating in VEX Robotics will definitely lead to your mental and physical growth.

If you are someone who is willing to start and has the opportunity, please do so. If you are someone who has participated for a long time, please continue! Anyway, VEX Robotics brings more joy than you would imagine!

This is IntroVex, your robotics guide to VEXcellence, see you next time!!