7.2V Metal Servo Bids Farewell To Jitter And Breakage Quickly. Micro Servo Is Very Stable.

The most troublesome things when playing withservos are probably "jitter" and "quick failure". Especially when you are happy to set up the project, but when the power is turned on, theservosqueaks and shakes, or when you go on strike while you are doing the work, the mood is terrible. When we are doing product innovation, time is money, but we cannot afford such trouble. In fact, many times, the problem is not with your code, but with the mismatch between the power supply and theservoitself. Today we will talk about how to use a 7.2V metal servo to smooth out this troublesome problem and make your project stable.

What are the benefits of 7.2V voltage?

Many people only look at the torque when choosing a servo, thinking that strong power is sufficient. This is actually a misunderstanding. Voltage is the "blood" of servo power, and 7.2V is like a golden gear for miniature metal servos. If you think about it, if the voltage is low, for example, only 5V is used, the servo will feel like it has not had enough to eat, the response will be slow, the torque will not be produced, and it will freeze under the slightest load.

Conversely, with enough 7.2V, the motor inside the servo can run at full speed, and the response speed is instantly increased. This means that your robot or model will move more smoothly and smoothly. Moreover, the advantage of metal gears is that they can withstand stronger impact caused by high voltage. Unlike plastic teeth, which may be swept away by force, 7.2V is the key to stimulating the performance of this "little steel cannon".

How to choose a suitable 7.2V metal servo

There are all kinds of servos on the market, and the parameter lists are dizzying. You first have to keep an eye on the "locked-rotor torque" number to see how much power it can output at 7.2V. This is directly related to whether your project can move, such as making a robotic arm. If the torque is not enough, it cannot even lift itself, let alone grab things.

Even though it is called a "miniature" servo, the volume and mounting hole spacing of different brands may vary slightly. Before buying, you must get the drawings (or installation dimensions drawings) and compare them with your structural parts. I have seen many friends buy the servo only to find that it cannot be installed, or the screw holes do not match up. They have to re-punch the 3D printed parts, which is too time-consuming. Also, check to see if its cord length and connectors are ones you commonly use. These small details can save you a lot of trouble.

What to do if the power supply is unstable

This is the most troublesome problem. Many servos vibrate abnormally, get hot, or even burn out. The culprit is insufficient power supply. For a 7.2V servo, it doesn’t mean that you can just find a 7.2V battery pack and connect it and everything will be fine. You have to consider the "instantaneous current". When the servo is started and blocked, the current will instantly surge to several times the normal operating current.

If your power supply or voltage stabilizing module cannot handle this instantaneous current, the voltage will be instantly pulled down, causing the servo control board to restart or cause logic confusion, resulting in jitter. There are two solutions: one is to use a battery with strong discharge capacity, such as a 2S lithium battery (fully charged 8.4V, just within the working range of the servo); the other is to connect a large-capacity capacitor in parallel to the power line close to the servo, such as 470uF or even. It is like a "reservoir", which can instantly replenish the current and stabilize the voltage.

Are metal gears really indestructible?

I have to pour some cold water on you. Although metal gears are much stronger than plastic ones, they are by no means indestructible. Its biggest benefits are "wear resistance" and "impact resistance". For example, if your project often needs to swing back and forth quickly, or has to withstand some external collision forces, metal teeth can greatly reduce the probability of tooth scanning.

But it should be noted that if the load is really too large and exceeds the physical limit of the servo, the first thing to break may not be the gear, but the motor or driver chip inside. The metal gear is too strong, but the impact force is transmitted to other fragile parts inside. Therefore, don't think that you can "ravage" it casually by using a metal servo. Designing the mechanical structure rationally to avoid leaving the servo in a stalled state for a long time is the right way to extend its life.

How to adjust program control when it always freezes?

Sometimes the hardware is selected correctly, the voltage is stable, and the servo still moves smoothly. This is probably because the pulse signal changes given in the program are too "hard". You directly change the servo from 0 degrees to 90 degrees instantly, and the command it receives is to "rush over at full speed". The result is that it clicks into place, which looks unnatural, and the internal gear shock is also large.

The solution is to add a "gradient" or "interpolation" algorithm to your control code. That is, every time you send a signal, the angle should not change too much. For example, it is divided into 10 steps, each step only increases by 9 degrees, and a little delay is added in the middle. In this way, the servo will rotate as smoothly as running water, which not only protects the servo, but also makes your work look more advanced and professional.

Do we need to pay attention to heat dissipation issues?

The micro servo is small and suffers from heat dissipation itself. When it works at high intensity for a long time, such as on a bionic robot leg, which has been working hard against the weight, heat is inevitable. If the case is hot to the touch (over 60 degrees), you need to pay attention. Overheating will not only cause the grease inside the steering gear to become thinner and flow out, but will also demagnetize the magnets of the motor, causing the torque to become smaller and smaller.

How to improve it? First of all, in terms of structural design, try not to completely enclose the steering gear in a confined space and leave some ventilation channels. Secondly, if the project permits, you can lower the operating voltage a little, such as using 7.2V instead of rushing to 8.4V. The performance loss is not big, but the heat generation can be reduced a lot. You can also set a "rest" time in the program, so that after the servo works at high intensity for a few seconds, relax and give it a chance to breathe.

After talking so much, the core thing is to let you understand that there are many tricks in choosing and using a small servo, but if you get it right, the project will be more than half successful. I wonder what is the most bizarre servo failure you have ever encountered while working on a project? Is it shaking like crazy or just smoking? Come to the comment area to share your experience of "trampling on pitfalls". Let's avoid lightning together. If you find it useful, don't forget to like it and share it with more friends!