Active control system

1. An active control system for a mass traveling along a guideway, comprising:

at least one displacement sensor measuring a displacement between a mass reference surface on the mass and a guideway reference surface on a guideway side;

at least one motion sensor;

at least one first filter comprising at least one of:

a low pass filter,

a notch filter, or

a combination of a low and high pass filter;

at least one second filter comprising at least one of:

a high pass filter,

a resonator or

a bandpass filter; and

a mixer,

wherein the at least one first filter is coupled to the at least one displacement sensor in a first branch to process signals from the at least one displacement sensor, and the at least one second filter is coupled to the at least one motion sensor in a second branch, which is in parallel to the first branch, to process signals from the at least one motion sensor, and

wherein signals from the first branch and signals from the second branch are processed and then mixed in the mixer to adjust a displacement of the mass reference surface from the guideway reference surface.

2. The active control system according to claim 1 , wherein a combined frequency spectrum of the at least one low pass filter and the at least one high pass filter is continuous.

3. The active control system according to claim 1 , wherein the first filter comprises a notch filter and the second filter comprises at least one bandpass filter.

4. The active control system according to claim 1 , wherein the first filter comprises a high pass filter and a low pass filter.

5. The active control system according to claim 1 , further comprising:

at least one integrator or derivative operator coupled to receive the filtered signals from the at least one motion sensor.

6. An active control system for a mass traveling along a guideway, comprising:

at least one displacement sensor measuring a displacement between a mass reference surface on the mass and a guideway reference surface on a guideway side;

at least one motion sensor;

at least one first filter; and

at least one second filter,

wherein the at least one displacement sensor is coupled to the at least one first filter and the at least one motion sensor is coupled to the at least one second filter,

wherein signals from the at least one displacement sensor are processed in the at least one first filter to form first filtered displacement sensor signals and signals from the least one motion sensor are processed in the at least one second filter to form second filtered motion sensor signals;

an integrator or a derivative operator is coupled to receive the second filtered motion sensor signals to produce integrated second filtered motion signals or derivative operated second filtered motion signals;

a mixer to superimpose the first filtered displacement sensor signals with the integrated second filtered motion signals or with the derivative operated second filtered motion signals to produce a synthesized pseudo-displacement signal; and

an actuator to adjust the displacement of the mass reference surface from the guideway reference surface based on the synthesized pseudo-displacement signal.

7. The active control system according to claim 6 , further comprising:

a comparator to determine a pseudo error signal, which is a difference between a predetermined reference displacement and the synthesized pseudo-displacement signal.

8. The active control system according to claim 7 , further comprising:

a controller coupled to receive the pseudo error signal and to control an actuator to adjust the displacement of the mass reference surface on the mass from the guideway reference surface.

9. The active control system according to claim 1 , wherein the at least one displacement sensor comprises at least one of an accelerometer, a gyroscope or rate sensor.

10. The active control system according to claim 1 , wherein the mass comprises a vehicle having bearings for moving along the guideway.

11. The active control system according to claim 10 , wherein the vehicle comprises a pod, the guideway comprises a track, and wherein the pod is configured to be suspended from or travel over the track.

12. A method for active control of a mass traveling along a guideway, comprising:

monitoring signals corresponding to a displacement of a mass reference surface on the mass with respect to a guideway reference surface on a guideway side;

monitoring signals corresponding to motion of the mass along the guideway;

processing the monitored displacement signals in at least one of a low pass filter, a notch filter or a combination of a low and high pass filter;

processing the monitored motion signals in at least one of a high pass filter, a resonator or a bandpass filter;

mixing the processed monitored displacement signals and the processed monitored motion signals in a mixer; and

controlling an actuator to adjust the displacement of the mass reference surface from the guideway reference surface according to the processed monitored displacement signals and the processed monitored motion signals.

13. The method according to claim 12 , wherein the processing comprises:

extracting relevant frequency content of the motion and displacement signals using filters comprising at least one of a band-pass, band-stop, notch, or resonator.

14. The method according to claim 12 , wherein the processing further comprises:

integrating, at least one time, the filtered signals from the at least one motion sensor.

15. The method according to claim 14 , wherein the processing further comprises:

superimposing the filtered displacement signals and the integrated filtered motion signals to produce a synthesized pseudo-displacement signal.

16. The method according to claim 15 , wherein the processing further comprises:

determining a difference between a predetermined reference displacement and the synthesized pseudo-displacement signal as a pseudo error signal.

17. The method according to claim 16 , wherein the controlling comprises:

controlling an actuator to adjust the displacement of the mass reference surface from the guideway reference surface based on the pseudo error signal.

18. The method according to claim 12 , wherein the guideway comprises a track and the mass comprises a vehicle with bearings configured for the vehicle to move over the track or to be suspended from the track.

19. The active control system according to claim 1 , further comprising an integrator or a derivative operator arranged in the second branch to process the second filtered motion sensor signals to produce integrated filtered motion signals or derivative operated motion signals in the second branch.

20. The active control system according to claim 19 , wherein the mixer is arranged to process the signals from the first branch and signals from the second branch by superimposing signals output from the first branch with the signals output from the second branch.