What Is The Most Simple And Practical Control Method To Use To Control The Steering Gear?

When it comes to playing withservos, many friends who are just getting started may have struggled with: What is the most convenient and reliable way to control it? There are a lot of solutions on the market, from the most basic PWM to the advanced bus control, it is dazzling to look at. Don’t worry, today we will explain it clearly and help you find the path that suits you best.

What is the easiest way to control the steering gear?

For those who just want to activate the rudder and quickly verify their ideas, the easiest way is to directly use PWM signal control. Today's microcontrollers, such as STM32, basically have PWM output function. A few lines of code can make theservorotate to a specified angle. The advantage of this method is that the threshold for getting started is very low. You can grab a lot of online tutorials and you can be up and running in ten minutes. You only need to connect the signal line to the PWM pin of the development board, give a high-level pulse width in the program, and theservowill be obedient. It is especially suitable for making a simple paw or shaking fan.

But simplicity also comes with a price. PWM control particularly relies on the timer resources of the microcontroller. If there are many servos in the project, such as making a six-legged robot, the timer will not be enough. Moreover, when multiple servos operate at the same time, if the program is not handled well, it is easy to get stuck, and the angles are not accurate enough. Therefore, PWM is very suitable for initial learning or scenarios with a small number of servos, allowing you to run, move and find the feeling first.

Is the steering gear control panel an IQ tax?

Many friends may ask, can't I just use the microcontroller to control it directly? Why do I need to spend more money to buy a control board? This is really not an IQ tax, it is more like hiring a "full-time secretary" for you. When you need to control a dozen or even dozens of servos to build a complex bionic robot or robotic arm, the resources of the microcontroller are instantly exhausted. The steering gear control board has its own dedicated driver chip and processor, which is responsible for processing the generation and timing of PWM signals, freeing the main control microcontroller to do more important things.

After using the control panel, you will find that the operation becomes particularly elegant. Many control panels support PC software. You can plan the motion trajectory of the servo by dragging key frames on your computer, just like making animations, and then burn the data into it with one click. The servo can move smoothly according to the sequence you arranged, completely free from the constraints of code. When we do complex projects, such as bipedal robots, they are basically equipped with a servo control board, which saves a lot of worry and makes the movement smoother.

How to choose between digital servo and analog servo

The control methods of these two brothers are actually the same, the difference lies in the internal "brain" and "heart". The analog servo relies on a comparator and drive IC. Given a PWM signal, it will strive to move to the corresponding position, which is simple and direct. There is an additional microcontroller inside the digital servo, which will "translate" the input PWM signal into a higher frequency control pulse to drive the motor. The advantage is faster response, more accurate braking, and greater holding power.

How to choose mainly depends on your project needs. If you are making a solar tracker or simple remote control car steering, the analog steering gear is completely sufficient and cost-effective. But if you want to perform 3D stunts on model aircraft, or the robot needs to respond quickly and accurately, digital servos are a must-have. The more expensive part of it is reflected in the closer control feeling and more precise action execution.

What is better about bus servo than PWM?

This is a good question. If PWM control is to assign a dedicated telephone line to each servo, then the bus servo is like setting up an internal company network for your servo group. All servos are hung on the same bus and are distinguished by addresses. Instructions can be given to all servos through one line. This is an obvious advantage when working on complex projects, such as robot arms or bionic fish. The wiring changes from a mess to a simple series line.

Even better is that the bus servo can not only receive instructions, but also "speak". It can provide real-time feedback of current temperature, voltage, load and precise angle. This means that your main controller can monitor the status of each joint at all times, and if it finds which servo is stuck or overheated, it can make adjustments or alarm immediately. This kind of intelligent two-way communication makes complex control reliable and provides a solid data basis for work such as debugging the robot's walking posture.

Is it possible to design the steering gear drive circuit by yourself?

If you have a basic knowledge of electronics, drawing a servo drive circuit yourself is definitely a cool attempt and a good way to deeply understand the principles. The core is actually not complicated. It just provides a stable power supply to the microcontroller, leads out the PWM signal pin, and then performs filtering and protection. A standard servo power module plus a minimum system board can build a basic drive circuit.

However, once the number of servos increases, the challenge becomes greater. The current when the servo is started is very large, and the simultaneous start of multiple channels can instantly lower the power supply voltage, causing the microcontroller to reset. If the electromagnetic interference on the circuit board is not handled well, the servo will vibrate randomly. Therefore, if you are a beginner or the project has time requirements, it is recommended to buy a mature driver board first. If you want to go deep into the bottom of the hardware and do it yourself, you will definitely gain more than you imagined, and you can solve many engineering problems that cannot be learned in books.

How to choose the control solution that best suits you

Having said all this, the key is to return to your specific project. You can take out a piece of paper and write down your needs. First, count how many servos are needed for the project. If there are less than 5 servos and the movements are simple, the single-chip microcomputer direct-connected PWM solution is the most efficient. If the number of servos exceeds 10, or complex linkage actions are required, then the servo control panel is your best partner. At the same time, you also need to consider your wallet. The analog PWM servo plus microcontroller is the cheapest, and the solution of digital bus servo plus control board has the strongest performance, but the budget is also the highest.

Another point that is easily overlooked is future scalability. You are making a simple robotic arm now, but in the future you want to add a walking chassis to it to double the degree of freedom. At this time, I chose the bus servo from the beginning, and it was very easy to expand. Just connect the hardware in parallel. Choosing a control scheme is like buying a tool. If you look a little further ahead, the follow-up path of the project will go much smoother.

After reading the above, do you have an idea of the steering gear control scheme? In your project, which control method do you prefer, or have you encountered any interesting pitfalls? Welcome to share your experience and opinions in the comment area. If you find the article useful, don’t forget to give it a like and share it with more friends who need it!