With the versatile and easy to assemble and maintain the design of LocTekMotion standing desks, it is no wonder that we take the synchronous motion of multiple lifting columns in a standing desk seriously.
With a standing desk with two lifting columns like our ET124, two-stage, dual motor, reverse design, rectangular columns desk kit, it is important to maintain strict control when it comes to absolute synchronization between the two actuators. This is not only to ensure that the desk surface remains perfectly horizontal and stable at all times, but also to maintain the aesthetics and smooth operation of a movable desk platform.
The ensured synchronization and smooth operation are what makes the use of electrical lifting columns and actuators more preferable in office and other professional environments.
Synchronizing multiple lifting columns essential in a two-motor desk which ensures that the two lifting columns move at the same pace. The synchronization of lifting columns is achieved via actuator controls that are either parallel or synchronous. In a parallel control setup, the motors are provided with constant voltage separately whereas in case of a synchronous control setup variable voltage is supplied to each actuator.
Just supplying constant or variable voltage to lifting columns or actuators isn’t enough to synchronize the operation and assured stability of a platform like a standing desk. It is also essential that two or more actuators working to move the lifting desk move at the same speed.
It is also critical to ensure that when the two lifting columns actuators move a load while maintaining equal load distribution across each actuator. To do this there is a constant positional feedback loop that apprises the position of each lifting column to each other. This is done using Hall Effect sensors and multiple turn potentiometers. We will further discuss in a bit more detail on how these work a bit later.
The positional feedback not only helps maintain an identical or desired position for both lifting columns, but it also helps the platforms correct any performance variance that is occurring due to a fault in the production of the lifting column.
The positional feedback is used to adjust the lag or discrepancy in the position of the two lifting columns. The way this is remediated is by upping or outputting a variable voltage to the actuator to match two actuator speeds. The positional feedback is necessary to determine how much voltage needs to be provided to each actuator.
In case if parallel control is used in an application where multiple lifting columns are used to move a load while maintaining equal load distribution across each actuator, unequal load distribution may occur, due to variable stroke speeds and this will ultimately cause excessive force on one of the actuators.
What is Hall Effect?
Edwin Hall, who discovered the Hall Effect, stated that whenever a magnetic field is applied in a direction perpendicular to the flow of electric current in a conductor, a voltage difference is induced. Using this theory, by attaching a magnet to the shaft of the motor we can detect if the shaft is parallel to them or not and by outputting this information in square waves, we can keep track of how many times the motor has spun. This helps us accurately synchronize the two lifting columns. The Hall Effect is used to digitally synchronize two or more lifting columns when lifting a platform like a standing desk.
Synchronizing using Potentiometer:
Multiple turn potentiometers, which in essence are variable resistors, can also provide an analog representation of the position of an actuator. By attaching a gearing system to the motor that turns the potentiometer, resistance rating is adjusted proportionally to the amount of travel that the actuator has made.
Synchronization of multiple lifting columns is central to the accurate, smooth and load-balanced operation of a two-motor standing table or lifting platform like ET124.
In conclusion, these are the technical details of how powerful motors, compact design, and innovative safety solutions makes LoctekMotion the leader in linear actuators, and lifting columns for applications in standing desks, conference tables, storage racks or kitchen cabinets.