Linear motion is an area of motion control which includes many technologies like linear motors, linear actuators, and linear rolling guides and bearings.
Linear Motion Control partly depends on the actuator and the linear actuator includes broad range of products.
A linear actuator is a mechanical device that converts energy such as the power from electricity ,air or liquid to create motion in a straight line and it may be used to apply a force.
Applications of linear motion control systems
- industrial automation and machinery
- machine tools
- computer peripherals such as disk drives and printers
- home automation
- medical imaging and diagnostics
- electronic manufacturing
- industrial test and inspection and
Linear drives move the carriage to the desired positions.
The most common drive technologies are ball-screw drives, lead-screw drives, and belt drives.
Linear motion contol application design Parameters
- Number of motion axes
- travel distance
- accuracy and repeatability
- lifetime requirements of the machine.
Force rquired to move an object should overcome the weight and friction of that object.
To calculat force required to move a object mass of object and center of gravity relative to each axis must be determined.
Determine the speed how fast the actuator need to move. This can be in millimeters per second or inches per second.
The force and speed calculated will help you in determining the mechanical power required and what kind of motor to use for the application.
Mechanical power = Force x Speed .
Stoke length is the distance the load or actuator need to travel.
Many actuators come in standard sizes. It is better to choose an actuator close in size to your requirement to save the cost of customization.
Commonly control derive of the linear motion control system will be selected based on stoke lenght of each axis for the application.
For example with ball screw linear actuators, the stroke length is limited to the length of the ball screw itself. Therefore, maximum stroke lengths tend to be around 3 meters.
But with belt-driven systems, there are no such restrictions and so stroke lengths can be higher than this, up to as much as 20 meters if required.
Different components of the linear motion contol systems are selected based on desired accuracy and repeatability of the application.
Control system also includes limit switches or feedback devices such as potentiometers and encoders for positioning purposes.
Types of screw actuators
- Lead-screw actuators
- Ball screw actuators
- Planetary roller actuators
- Lead-screw actuators with a threaded nut that moves with a screw.
Application where accuracy and repeartability is very important screw driven positioning systems are used.
Linear Motion Control applications
- Linear motion control in industrial machines for
- positioning loads
- pick and place operations
- filling operations
- automated warehouses
- cutting machines
- painting machines
- Linear motion control in medical application
- operating room beds
- X-ray machines
- MRI and CT Scanners
- dentist chairs
- Portable Respirators
- Surgical Robotics
- Nuclear Medicine
- Linear motion control in medical lab automation
- pick and place
- DNA sampling
- Cell culture
- Air displacement Drug testing, and
- Drug dispensing
- Linear motion control in food industry for material handling equipment.