A engine is only as good as its control and its request for retrial control system. The request for retrial controller essentially controls the engine heart beat. It is directly responsible for the request for retrial of the machine. A request for retrial controller for a ball screw engine principles is not correct enough for a linear motor driven engine tool.
In a accepted drive, the request for retrial controller sends a signal to servo motor that uses a rotary encoder or glass scale to verify the movement. The encoder or glass scale sends a signal back to the control to let it know that the move command has been made. If the engine has glass scales on the axis, positioning must also be verified by a signal going from the control to the scale. This is one of the reasons that a ball screw is exiguous in speed. The main suspect that a ball screw principles will always be exiguous in accuracy is because of all the components causes backlash.
Industrial Encoder
The pitch of a ball screw is never perfect. When a engine is calibrated, values to correct the pitch error in these drives are entered into parameters that the request for retrial controller checks. The request for retrial controller must check these values in its calculations to assure positioning accuracy. Therefore, when a ball screw principles is moved at a high feed rate overshoot and or undershoot will occur. Because a rotary encoder basis positioning on the whole of divisions moved by a rotary disk, it does not and can not take into consideration any thermal conditions such as:
* Ball screw expansion
* Twisting in the drive due to servo torque
* Slop or thermal expansion in ball nut or coupler
* Backlash in the drive
A linear motor principles does not use ball screws and servo motors. The principles relies on direct feedback from a linear scale for positioning, reporting an exact position and not a theoretical position. Because there are no mechanical parts, there is no backlash.
Because the principles does not have to compensate for ball screw pitch error and because the control gets position feedback directly from a linear scale mounted directly on the spicy axis and not from a rotary encoder, this creates a closed loop system. It also means that the control doesn't have to process as much facts for each move. Therefore a more simplified request for retrial control principles is a good fit for an all linear system.
engine Tool form - request for retrial Controller & Linear Motor Drives