Why Mikrolar Actuators?
The quality of the actuators used directly affects the quality of Stewart Platforms produced. We have used a number of actuator manufacturers over the years, but we repeatedly found that we needed to "tweak" each actuator. With improved interior construction and software, we now offer the actuators we personally create for our company's Hexapod systems. Every actuator is designed, assembled, and tested in-house so we can meet your required specifications.
Axial and Radial Stiffness
Most actuators have decent axial stiffness (the ability to resist tension and compression along the length of the rod). People often equate this with the diameters of its rod and screw; however any backlash from the preload on the nut, drive train, and anti-rotation devices must be taken into account as well. Axial stiffness directly determines accuracy of length, and results in chatter if done poorly.
Unfortunately, because actuators do not have any support along the body itself, most often they do not have very good radial stiffness (the ability to resist forces from the side). While there are many reasons for this, one large contributor is the nose bushing. If this bushing is too loose, the rod can move around. While this might have only a very small effect on overall length of the actuator (the delta difference is minor), it can cause huge stiffness issues. For example: picture a sturdy table with four legs. Now insert a small joint in the center of each leg. Pressure on the table top will then cause it to move, as these small joints allow it to. Radial stiffness directly determines the overall stiffness of the machine.
Mikrolar's Actuator Mapping Jig.
Along with hardware improvements, Mikrolar has developed software for use with the actuators to further improve overall accuracy. Actuators can also be specially ordered with an "accuracy package" of linear encoders for improved positional accuracy.