Test Measurement and Control >> Motion Control System

Motion control can be simply defined as the precise control of anything that moves. The system consists of advance motion controllers, wiring and connectivity devices, motor drive units, software tools and interface to third party devices. Controllers generate trajectories, which the motor follows. Drives then take the signals sent by the controller and change them into signals that will actually move the motor. Feedback devices are used to close the control loop in closed-loop systems. The parts of the system that National Instruments makes are the controllers, the software to run the controllers, and the drives. There are many different kinds of controllers, drives, motors, and feedback devices. You choose each component based on the requirements for your application. For example, consider an application that requires high torque, high speed, and precise control. Since servomotors generally have higher torque at high speeds, a servomotor would be the most appropriate. After choosing the type of motor, you can then find a controller that controls servomotors. Since you want precise control, a PCI-7344 motion control board would be appropriate since it can control servomotors and is precise. After choosing the motor, you can also choose the type of drive to use. If the servomotor is a DC brushed servomotor and requires less than 8 amps continuous current and 20 amps peak, you can use the nuDrive with an adaptor to connect to the PCI-7344. Since you are using a servomotor, you also need to consider the type of feedback device to use for closing the control loop. If you want to do position control, you can use an incremental encoder that mounts on the motor and easily interfaces with the PCI-7344 controller.

When building a motion control system, there are many things to consider. Some of the questions you may want to ask yourself when building a system are as follows:

What type of motion is required for the system?

What size of motors will be necessary?

What type of drive works your type of motor?

What type of environment will the system be in?

How accurate does the motion need to be?

Will feedback be necessary and how accurate does that feedback need to be?

The answers to these questions vary from system to system. The following sections include links for more specific information to help you when planning your motion control system.

Application Notes and Tutorials:
  • Controlling an X-Y stage with a Joystick
  • Fiber-Optic Component Inspection Using Integrated Vision and Motion Components
  • High-Precision Motion Control with Piezo Actuators and NI Motion 5.2
  • Integrating Measurements with Vision and Motion.
Added flexibility and potential for lower system cost is increasing the popularity of this computer based motion solutions

We can provide Motion Control System:
  • Upto 6 axis Control.
  • Designed for position and velocity control in variety of electromechanical configuration.
  • Optimized for use in test and measurement automation, laboratory automation, industrial control, Cartesian robotics, material handling, integrated machine vision, machine tool control and OEM applications.
Components of a Motion Control System:

Motion Control System

The figure below shows the different components of a motion control system.

Application Software -
You can use application software to command target positions and motion control profiles.

Motion controller -
The motion controller acts as brain of the of the system by taking the desired target positions and motion profiles and creating the trajectories for the motors to follow, but outputting a 10 V signal for servo motors, or a step and direction pulses for stepper motors.

Amplifier or drive -
Amplifiers (also called drives) take the commands from the controller and generate the current required to drive or turn the motor.

Motor -
Motors turn electrical energy into mechanical energy and produce the torque required to move to the desired target position.

Mechanical elements -
Motors are designed to provide torque to some mechanics. These include linear slides, robotic arms, and special actuators.

Feedback device or position sensor -
A position feedback device is not required for some motion control applications (such as controlling stepper motors), but is vital for servo motors. The feedback device, usually a quadrature encoder, senses the motor position and reports the result to the controller, thereby closing the loop to the motion controller.

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