Passive motion isolation system
A passive motion isolation system for motion-sensitive equipment is disclosed. The passive motion isolation system has a three-axis free motion platform mounted on a base subject to ambient motions. A vibration isolation subsystem is coupled between the motion-sensitive equipment and the three-axis free motion platform.
1. A motion isolation system for motion-sensitive equipment, comprising:
a base subject to ambient motions;
a three-axis free motion platform mounted on the base, the three-axis free motion platform coupled with the motion-sensitive equipment, the three-axis free motion platform including:
a first axis carriage free to move along a first axis rail,
a second axis carriage free to move along a second axis rail,
a third axis carriage free to move along a third axis rail, each of the first axis rail, the second axis rail, and the third axis rail having a finite length between respective ends;
a plurality of resilient firm stops, a resilient firm stop from the plurality of resilient firm stops located proximate each end of each of the first axis rail, the second axis rail, and the third axis rail to limit a range of motion of the respective carriage in both directions along the rail; and
a plurality of resilient soft stops, a resilient soft stop from the plurality of resilient soft stops located proximate each end of each of the first axis rail, the second axis rail, and the third axis rail,
wherein each resilient soft stop is configured such that a carriage nearing an end of the respective rail contacts the resilient soft stop located proximate the end of the rail before contacting the corresponding resilient firm stop.
2. The motion isolation system of claim 1 , wherein
the second axis rail is attached to, and moves with, the first axis carriage, and
the third axis rail is attached to, and moves with, the second axis carriage.
3. The motion isolation system of claim 1 , further comprising a counterbalance spring to offset a total weight, the total weight including a weight of the third axis carriage, and a weight of the motion-sensitive equipment.
4. The motion isolation system of claim 3 , wherein the counterbalance spring comprises at least one constant force spring.
5. The motion isolation system of claim 1 , wherein each resilient soft stop extends further along the respective rail and has a smaller cross-sectional area than the corresponding resilient firm stop.
6. The motion isolation system of claim 1 , further comprising:
a first axis linear stage including the first axis carriage;
a second axis linear stage including the second axis carriage, the first axis linear stage and the second axis linear stage orthogonal to each other and essentially horizontal; and
a third axis linear stage including the third axis carriage, the third axis linear stage being orthogonal to both the first axis linear stage and the second axis linear stage and essentially vertical.
7. The motion isolation system of claim 1 , further comprising:
a coupler bracket, the three-axis free motion platform coupled with the motion-sensitive equipment via the coupler bracket.
8. The motion isolation system of claim 7 , wherein the coupler bracket comprises:
a support plate attached to the third axis carriage;
four elongate resilient pillars, each elongate resilient pillar having a first end affixed to the support plate, a length extending from the support plate parallel to a vertical axis, and a second end; and
a mounting bracket to couple the motion-sensitive equipment to the second ends of the four elongate resilient pillars.
9. The motion isolation system of claim 8 , wherein the mounting bracket is configured such that all or a portion of the motion-sensitive equipment is disposed between the four elongate resilient pillars.
10. The motion isolation system of claim 9 , wherein the mounting bracket is configured such that the motion-sensitive equipment does not contact the four elongate resilient pillars and the support plate.
11. The motion isolation system of claim 8 , wherein:
each of the four elongate resilient pillars comprises first and second segments,
the coupler bracket further comprises a first frame,
the first segments of each of the four elongate resilient pillars couple the mounting bracket to the first frame, and
the second segments of each of the four elongate resilient pillars couple the first frame to the support plate.
12. The motion isolation system of claim 8 , wherein:
each of the four elongate resilient pillars comprises first, second, and third segments,
the coupler bracket further comprises first and second frames,
the first segments of the four elongate resilient pillars couple the mounting bracket to the first frame, the second segments of the four elongate resilient pillars couple the first frame to the second frame, and the third segments of the four elongate resilient pillars couple the second frame to the support plate.
13. The motion isolation system of claim 8 , further comprising:
at least one grommet to limit a range of motion of the mounting bracket with respect to the support plate.
14. The motion isolation system of claim 13 , wherein each of the at least one grommet comprises:
a resilient grommet attached to the support plate; and
a post extending from the mounting bracket through a center hole in the resilient grommet.
15. The motion isolation system of claim 7 , further comprising a counterbalance spring to offset a total weight, the total weight including a weight of the third axis carriage, a weight of the coupler bracket, and a weight of the motion-sensitive equipment.
16. The motion isolation system of claim 15 , further comprising:
a first axis linear stage including the first axis carriage;
a second axis linear stage including the second axis carriage, the first axis linear stage and the second axis linear stage orthogonal to each other and essentially horizontal;
a third axis linear stage including the third axis carriage, the third axis linear stage being orthogonal to both the first axis linear stage and the second axis linear stage and essentially vertical,
wherein the third axis linear stage comprises the counterbalance spring.
17. The motion isolation system of claim 1 , further comprising:
a coupler bracket,
wherein the coupler bracket is coupled between the third axis carriage and the motion-sensitive equipment.
18. A motion isolation system for motion-sensitive equipment, comprising:
a base subject to ambient motions;
a three-axis free motion platform mounted on the base, the three-axis free motion platform coupled with the motion-sensitive equipment, the three-axis free motion platform including:
a first axis carriage free to move along a first axis rail,
a second axis carriage free to move along a second axis rail,
a third axis carriage free to move along a third axis rail, each of the first axis rail, the second axis rail, and the third axis rail having a finite length between respective ends;
a plurality of first stops, a first stop from the plurality of first stops located proximate each end of each of the first axis rail, the second axis rail, and the third axis rail to limit a range of motion of the respective carriage in both directions along the rail; and
a plurality of second stops, a second stop from the plurality of second stops located proximate each end of each of the first axis rail, the second axis rail, and the third axis rail,
wherein each second stop is configured such that a carriage nearing an end of the respective rail contacts the second stop located proximate the end of the rail before contacting the corresponding first stop,
wherein the first stop has a first firmness,
wherein the second stop has a second firmness, and
wherein the first firmness is greater than the second firmness.