Effective Servo Motor Control

Technology Articles | May 27, 2011

Servo motor control is the key component for automatic system efficiency. Servo Motors are electromechanical devices that are designed to receive error-sensing negative feedback, analyze and adjust the performance of a mechanism. It is this attribute of rectifying or controlling a mechanism gives the motor the name of "servo motor".

Servo motor control is the key component for system efficiency. Servo Motors are electromechanical devices that are designed to receive error-sensing negative feedback, analyze and rectify the performance of a mechanism. It is this attribute of rectifying or controlling a mechanism gives the motor the name of "servo motor". For example, for a position servo motor, various techniques can be used to provide feedback on the position of the target load. This feedback is used to control the performance of the application. Other applications of servo motors can be found in speed control via governor and remote control devices too. Servo controls thus involves several devices in order to allow the load item to perform as desired.

A glimpse into servo motor would be a good explanation. The servo consists of three wires: ground (black), power (red), and command (typically white). Servos are commanded through the technique of "Pulse Width Modulation," or PWM servo so basically signals are sent through the command wire. The width of a pulse indicates the modulation and thus defines the desired position. This gives a reference to the servo motor to monitor the performance of the mechanism.

Servo motor control happens fundamentally on two things. The first is based on the command given. The performance of the mechanism is monitored by the device to ensure that it follows the command. Few commands can be like velocity, torque, acceleration and position. The second is based on the disturbance rejection characteristics. This takes into consideration anything from torque disturbances on the motor shaft to inaccurate motor parameter estimations. The combination of both kinds of control fundamentals makes the system complete and enhances overall performance.

Nowadays, servo motor controls find heavy usage in helicopters, automobiles, boats, planes, robotics and industrial purposes. It is majorly because of the introduction of PIC microcontrollers to monitor multiple servomotors simultaneously and thus provide more versatility to the applications.

The control of a servo motor will require the services of power semiconductor. One type of semiconductor is the SCR (silicon controller rectifier) which is connected to the AC line voltage. Servo controls like this is usually employed in cases where large amounts of power (load) is to be regulated and relatively high motor inductance. With streamlined and automated servo motor control one can not only reduce the turnaround time, improve system efficiency but also contribute to environment with effective regulation of power usage.

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Article by Jenny, content writer at Inter-Dev Internet Marketing Company, on behalf of Servotronix.com – Custom Servo Drives