The servo system is one of the best technological breakthroughs in the 1800s. Through the years, it was perfected by engineers and scientists until they created a variety of categories for these machines. This paved way for countless inventions. If you’re an aspiring inventor or engineer, the servo system is one of the best topics to learn and understand.
Much of what brings confusion to people is the difference between the servo drive and motion controller. Are they the same or are there differences between these two components? Tune in to find out.
What Is a Servo Drive?
The servo drive is a part of the servo system that receives and amplifies signals from the control system. After amplification, the servo drive transmits the electric current to the servo motor to produce the motion instructed by the command signal.
What Is a Servo Controller
A servo controller, also known as the motion controller, is the part of the servo responsible for closing the loop in a system. It works by constantly detecting and assessing the encoder signals to control the motor.
The simplest function of a servo controller is to hold the motor in a specific position. If there are disturbances that cause the motor to change in position, the servo controller detects the error signal it gives off. It will then translate it into a command that moves the motor back to its original position.
On a more advanced note, the servo motor control is responsible for moving the motor to a new position. The controller creates a specific motion profile using a particular speed. The controller will then command a specific position at a precise time. This causes the servo motor to rotate at the desired motion profile.
How Do Servo Drives Work and How Are They Controlled
The components of a servo system function differently. But they work hand-in-hand to make a machine work. Believe it or not, there is a symbiotic relationship between these components. Here’s how.
Servo motor control signals
As discussed, the servo controller gives off the signal. The servo drive will then amplify these signals and transfer them to the motor. The servo motor, on the other hand, is responsible for carrying out the process. However, this component can also send a signal back.
The control signal represents a specific velocity, torque, or position. The sensor of the servo motor assesses the actual status of the machine and reports it back to the servo drive. The servo drive will then compare this actual motor status to the commanded status. This is when it alters the frequency, pulse, and voltage of the command to fill the discrepancy between the actual status and the desired status.
Servo motors do not only rely on the signals from the “brain” or the controller. They have their own mechanism that helps them match the instructions. Servo motors follow several parameters such as proportional gain or stiffness, derivative gain or damping, and feedback gain. All of which is adjusted to perform the command as precisely as possible. This process of adjusting these facets is called performance tuning.
How to use a servo with a microcontroller
Servos are used in a variety of fields such as automation and robotics. It is inherent that the machines in these facets use computers to function. The most prominent type of computer used to control these machines is called a microcontroller. This is a computer inside a single integrated circuit responsible for performing one task and executing a specific application.
Microcontrollers contain memory storage units, programmable peripherals, and a processor. A good example of a device controlled by a microcontroller is the television. It is controlled by a remote that signals it to perform depending on the needs of the owner.
Analog and digital servo drives can also be controlled by a microcontroller through Pulse Width Modulation or PWM. This is a powerful technique employed in various applications such as speed, power, and communication control.
This strategy works by reducing the power delivered through an electrical signal by chopping it into discrete parts. This is suited for running inertial loads such as motors that are not affected by continuous switching.
However, the switching frequency has to match the power needed by the motor to run. This rate varies depending on the load and application. In electric stoves, for example, the switching has to be done several times in a minute. For a motor drive, it has to be switched at least ten times. The longer the switch is on, the more power is given to the motor to work.
Now that you know the differences between a servo drive, a servo controller, and a servo motor, you are one step closer to creating your own machine. But your learning shouldn’t stop here. Visit reliable sites such as The Tech Hacker. The more insight you have about servos, the closer you are to creating functional and efficient machines.