Going Digital – The Benefits of Digital R/C Servos
Despite the numerous similarities, digital servos provide many benefits over traditional analog servos. This article will discuss some of the advantages of choosing digital servos for your next R/C project and address the relatively few drawbacks. A future article will describe the technical differences between the two.
The primary benefits of a digital servo relative to an analog servo are:
- Improved holding torque
- Finer resolution
- Smaller deadband
- Faster acceleration
- Programmable functionality
Improved Holding Torque
Holding torque is the resistance of the servo motor to leaving its commanded position when it is under load. The improved holding torque of a digital servo makes the digital choice ideal for applications where accuracy is important even when the servo is loaded, such as helicopter applications, and competition aerobatic airplanes.
Finer Resolution
The resolution of the servo refers to the smallest repeatable discrete movement of the servo. Finer resolution is very handy in accurately trimming the servo to a centered control surface position, as well as being able to make smaller control corrections.
Smaller Deadband
Deadband refers to the minimum position error before the servo responds by trying to correct its position. The idea behind deadband is to prevent the noise in the command signal from causing the servo to chase its commanded position. A smaller deadband means more accurate positioning, and a faster response to small control inputs.
Faster Acceleration
The faster acceleration and deceleration of the digital servo allows for very abrupt control inputs, which can make a big difference in a tough competition environment, or when you really need the controls to respond.
Programmable functionality
One of the most powerful differences between analog and digital servos is the ability to program digital servos to meet the very specific needs of your application. Some of the programmable features include end point adjustment, failsafe position, deadband adjustment, direction and speed of rotation, and even where the servo centers.
The Drawbacks of Digital Servos
The advantages of digital servos do come at a cost, namely power consumption and price. The impact of increased power consumption is mitigated by new battery technology that continues to increase energy density (energy stored per unit of battery weight). As a result of the increased power consumption, today’s LiPo batteries and efficient motors are a good compliment to digital servos.
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