144162
HIGH SPEFD LINEAR MOTION MECHANISM
FIELD OF THE INVENTION
This invention is related generally to a motion mechanism for a machine tool system,
and a machine tool system incorporating such a mechanism.
BACKGROUND OF THE INVENTION
Machine tool systems that allow for the machining of a surfaces arc kn;iwn. In
particular, machine tool systems which translate diamond cutting tools relative to a
surface to cut and machine the surface are known. In these systems motion is
provided to the cutting tool, or the surface to be machined or both.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention, there is provided a
motion mechanism. The motion mechanism comprises: a payload support portion
configured to support a payload; a ground portion; a first side portion connected to the
payload support portion at a first contact point and connected to the ground portion at
a second contact point; a second side portion connected to the payload support portion
at a third contact point and connected to the ground portion at a fourth contact point; a
first transducer arranged to provide a force to the first side portion in a first linear
direction when actuated so that the first side portion provides a force to the payload
support portion at the first contact point in a second direction substantially orthogonal
to the first direction; and a second transducer arranged to provide a force to the
second side portion in a third linear direction when actuated so that the second side
portion provides a force to the payioad support portion at the third contact point in a
fourth direction substantially orthogonal to the third direction.
In accordance with another embodiment of the present invention, there is provided a
motion mechanism. The motion mechanism comprises: a payload support portion
configured to support a payload; a ground portion; a first side portion connected to the
payload support portion at a first contact point and connected to the ground portion at
1

144162
a second contact point; a second side portion connected to the payload support portion
at a third contact point and connected to the ground portion at a fourth contact point;
and a first transducer arranged to provide a force to the first side portion in a first
linear direction when actuated so that the first side portion provides a force to the
payload support portion at the first contact point in a second direction substantially
orthogonal to the first direction.
In accordance with another embodiment of the present invention, there is provided a
motion mechanism. The motion mechanism comprises: a payload support portion
configured to support a payload; a ground portion; a first side portion connected to the
payload support portion at a first contact point and connected to the ground portion at
a second contact point; a second side portion connected to the payload support portion
at a third contact point and connected to the ground portion at a fourth contact point: a
first transducer arranged to provide a force to the first side portion in a first direction
when actuated so that the first side portion provides a force to the payload at the first
contact point in a second direction substantially orthogonal 10 the first direction; U:K: a
spring arranged to provide a bias force to the second side portion in a third: direction
so that the second side portion provides a force to the payload at the third contact
point in a fourth direction substantially orthogonal to the third direction.
In accordance with another embodiment of the present invention, there is provided a
motion control system. The motion control system comprises: a workpiece support
configured to support a workpiece; a motion mechanism comprising: .1 payload
support portion configured to support a payload; a ground portion; a first side portion
connected to the payload support portion at a first contact point and connected to the
ground portion at a second contact point: a second side portion connec;ed to the
payload support portion at a third contact point and connected to the ground portion at
a fourth contact point; a first transducer arranged to provide a force to the first side
portion in a first linear direction when actuated so that the first side portion provides a
force to the payload support portion at the first contact point in a second direction
substantially orthogonal to the first direction; and a second transducer arranged to
provide a force to the second side portion in a third linear direction when actuated so
2

144162
that the second side portion provides a force to the payload support portion at the third
contact point-in a fourth direction substantially orthogonal to the third direction; and a
controller unit configured to control the transducers to control the motion of the
cutting tool to cut the workpiece.
In accordance with another embodiment of the present invention, there is provided a
motion mechanism. The motion mechanism comprises: a base portion; a flexure
portion comprising: a payload support portion configured to support a payload; a first
plurality of elongated portions extending substantially in a first direction and
contacting the payload support portion; and wherein the flexure portion contacts the
base portion; and a transducer arranged to provide a force to the payload support
portion in a second direction when actuated, the second direction .substantially
orthogonal to the first direction.
In accordance with another embodiment of the present invention, there is provided a
motion control system. The motion control system comprises: a workpiece support
configured to support a workpiece; a motion mechanism comprising: a base portion; a
flexure portion comprising: a payload support portion configured to support a
payload; a first plurality of elongated portions extending substantially in a first
direction and contacting the payload support portion, wherein the flexure portion
contacts the base portion; and a transducer arranged to provide a force to the payload
support portion in a second direction when actuated, the second direction substantially
orthogonal to the first direction; and a controller unit configured to control the
transducers to control the motion of the cutting tool to cut the workpiece.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a top view of a motion mechanism according to a preferred embodiment of
the invention.
Figure 2 is a perspective view of the motion mechanism of Figure 1.
3

144162
Figure 3 is a top view of a motion mechanism according to another preferred
embodiment of the invention.
Figure 4 is a schematic of a machine tool system according to an embodiment ot the
invention.
Figure 5 is a schematic view of a motion mechanism according to another preferred
embodiment of the invention.
Figure 6 is a schematic view of the motion mechanism as illustrated in Figure 5,
where the transducer is providing a force on the flexure portion.
Figure 7 is a schematic view of a motion mechanism according to yet another
preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to presently preferred embodiments ot" the
present invention. Wherever possible, the same reference numbers will be used
throughout the drawings to refer to the same or like parts.
In a preferred embodiment of the invention, a simple four bar motion mechanism is
provided to constrain the motion of a payload. Preferably, opposing bars of the
mechanism are of equal length so that the resultant motion is parallel for small
displacements. The bars adjacent to the payload may be connected to motion
transducers in such a way that a mechanical advantage can be applied between the
transducer and the payload. In one embodiment two transducers may be used, and
may be driven in opposite polarity. Alternatively, the mechanism may include a
single transducer with a spring acting as an opposing force.
The linear motion provided by the transducer or transducers beneficially allows she
motion mechanism to be formed to be compact in size. In turn, the compact size
enables the motion mechanism to be operated with a relatively high bandwidth.
4

144162
Figures 1 and 2 illustrate a motion mechanism 10 according to a preferred
embodiment of invention. The motion mechanism 10 includes a payload support
portion 12, a first side portion 14, a second side portion 16, and a grounded portion
18. The motion mechanism 10 provides motion to the payload support portion 12 in
the plane of the paper of Figure 1 (the x-y plane), and specifically provides horizontal
motion (along the x-axis) to the payload support portion 12. In this embodiment the
bars of the four bar mechanism include the first and second side portions 14 and 16,
and the grounded portion 18, and the payload support portion 12.
The payload support portion 12 is configured to support a payload 20, such as a
cutting tool or laser head, for example. If the payload 20 is a cutting tool, the cutting
tool may be a diamond cutting tool, for example. If the payload 20 is a laser head, the
laser head may include an end of an optical fiber and corresponding optics, where an
opposing end of the optical fiber is optically coupled to a laser, for example.
The first side portion 14 is connected to the payload portion 12 at a first contact point
30 and connected to the ground portion 18 at a second contact point 32. The second
side portion 16 is connected to the payload portion 12 at a third contact point 34 and
connected to the ground portion 18 at a fourth contact point 36.
The motion mechanism 10 also includes a first transducer 40 and a second transducer
42 to provide motion to the payload support portion 12 and thus to the payload 20.
The first transducer 40 is arranged to provide a force to the first side portion 14 in a
first linear direction when actuated so that the first side portion 14 provides a force to
the payload support portion 12 at the first contact point 30 in a second direction
substantially orthogonal to the first direction. For example, in the configuration
shown in Figures 1 and 2, if the first linear direction is the +y direction, the second
direction is the +x direction. Conversely, if the first linear direction is the -y
direction, the second direction is the -x direction.
Similarly, the second transducer 42 is arranged to provide a force to the second side
portion 16 in a third linear direction when actuated so that the second side portion 16
5

144162
provides a force to the payload support portion 12 at the third contact point 34 in a
fourth direction substantially orthogonal to the third direction. For example, in the
configuration shown in Figures 1 and 2, if the third linear direction is thereby direction,
the fourth direction is the -x direction. Conversely, if the third linear direction is the -
y direction, the fourth direction is the +x direction.
In this embodiment, the transducers 40 and 42 are arranged in a "push-pull
configuration, i.e., if the first linear direction and the third linear direction are
opposite to one another, the second direction is substantially the same as the fourth
direction. For example, if the first linear direction is the +y direction and the third
linear direction is the -y direction, both the second direction and the fourth direction
are the +x direction. Thus, in this ease the first transducer 40 causes the first side
portion 14 to "push" on the payload support portion 12, while the second transducer
42 causes the second side portion 16 to "pull" on the payload support portion 12. The
transducers 40 and 42 are driven with opposite polarity, i.e.. one transducer is driven
to expand, while the other to contract, to provide motion to the payload support
portion 12 in the same direction.
The contact portions 30, 32. 34 and 36 preferably comprise a rigid or semi-rigid
material to transfer the forces generated by the transducer. The contact portions 30.
32, 34 and 36 are also preferably relatively narrow in the plane of the motion (the x-y
plane in Figure 1), for example, they may have a cross-section in the plane of the
motion of between 0.1mm X 0.1 mm and 3mm X 3mm, for example. The relatively
narrow contact portions allow the contact portions to sufficiently ilex. For example,
when the transducer 40 provides a force in the +y or -y direction, the contact portion
32 between the ground portion 18 and the first side portion 14 should be able to flex
to allow the first side portion 14 to rotate about the contact portion 32. Likewise,
when the transducer 42 provides a force in the + y or -y direction, the contact portion
36 between the ground portion 18 and the second side portion 16 should be able to
flex to allow the second side portion 16 to rotate about the contact portion 36.
6

144162
In this embodiment, both the first and second side portions 14 and 16 are substantially
L-shaped with the bottom portions of the Ls pointing toward each other. The present
invention is not limited to first and second side portions having a particular s'-iape, and
may be shaped other than substantially L-shaped.
The contact points 30, 32, 34 and 36, the payload support portion 12, the first and
second side portions 14 and 16 and the ground portion 18 may all be formed from the
same block of material. In this way the contact points 30, 32, 34 and 36, the payload
support portion 12, the first and second side portions 14 and 16, and the ground
portion 18 may all be integral. For example, the contact points 30, 32, 34 and 36, the
payload support portion 12, the first and second side portions 14 and 16 and the
ground portion 18 may all be formed from a titanium alloy, aluminum alloy or steel
block. The block may be machined by wire electrical discharge machining (IIDM) or
conventional milling, for example, to form the contact points 30, 32, 34 and 36, the
payload support portion 12, the first and second side portions 14 and 16 and the
ground portion 18 in an integral fashion.
The ground portion 18 may comprise a ground block, and the ground block may
include one or more spray nozzles 50 thereon to provide a spray towards the payload
support portion 12. For example, if the payload 20 is a cutting tool, the spray nozzles
50 may provide a spray of air or other gas to blow away chips or other debris formed
when the cutting tool cuts into a workpiece.
The transducers 40 and 42 may be piezoelectric transducers, for example. For
example, the transducers may be formed of piezoelectric crystalline stacks, and may
comprise PZT material, for example.
The motion mechanism 10 may also include a position probe 60 to detect the position
of the payload support portion 12. The position probe 60 provides feedback when the
motion mechanism 10 is controlled to position the payload support portion 12 and its
payload 20. The position probe 60 may be at least one of a capacitance gauge, a laser
range finder, or an interferometer, for example.
7

144162
The motion mechanism 10 may also include a constrained layer 70 tha; acts to
provide viscoelastic damping to the motion of the payload support poruon I 2 and thus
the payload. This damping reduces overshoot and ringing in the actual position of the
payload 20 relative to the commanded position of the payload 20 when the payload 20
is driven. The constrained layer 70 may be positioned between the ground portion 18
and the payload support portion 12. The constrained layer may comprise a
viseoelastic material such as polypropylene, for example.
The linear motion provided by the transducers 40 and 42 allows the motion
mechanism to be formed to be compact in size, and thus may be operated with a
relatively high bandwidth. The resonant frequency of the motion of the payload
support portion 12 may be greater than about 4 kHz, for example.
Figure 3 illustrates another preferred embodiment of the invention. In the
embodiment illustrated in Figure 3, one of the transducers is replaced with a spring
80, but is otherwise the same. The same reference numerals denote the same
components in Figures 1, 2 and 3. The spring 80 provides a biasing and restoring
force to the first side portion 14 in the first direction so that the first side portion 14
provides a force to the payload support portion 12 at the second contact point 32. The
spring 80 may be of a bulk material that provides a torsional stiffness to act as the
spring.
Figure 5 illustrates another preferred embodiment of the invention where the motion
control system is of a flexure design. The motion mechanism 510 includes a base
portion 512, a flexure portion 514 and a transducer 516. The motion mechanism 510
provides motion to a payload support portion 518, which is part of the flexure portion
514, in the plane of the paper of Figure 5 (the x-y plane), and specifically- provides
horizontal motion (along the x-axis) to the payload support portion 518. The spring
80 may be eliminated if any or all of contact points 30, 32, 34 and 36 are made so that
their combined torsional stiffness acts as the spring. In this way the spring may be
formed in the bulk material of the motion mechanism.
8

144162
The transducer 516 may be a piezoelectric transducer, for example. For example, the
transducers 516 may be formed of piezoelectric crystalline stacks, and may comprise
PZT material, for example.
In a similar fashion to the embodiments as illustrated in Figures 1 and 2, in this
embodiment, the payload support portion 518 is configured to support a payload 520,
such as a cutting tool or laser head, for example. If the payload 520 is a cutting tool,
the cutting tool may be a diamond cutting tool, for example. If the payload 520 is a
laser head, the laser head may include an end of an optical fiber and corresponding
optics, where an opposing end of the optical fiber is optically coupled to a laser, for
example.
The ilexure portion 514 includes a first plurality of elongated portions 530. One end
of each of the first plurality of elongated portions 530 contacts the paylot.d support
portion 518. Each of the first plurality of elongated portions 530 extends substantially
in a first direction, for example, in the y-direction as illustrated in Figure 5.
The flexure portion 514 may also include a second plurality of elongated portions 534
and bar portions 536. The second plurality of elongated portions 534 extend
substantially in the same direction as the first plurality of elongated portions 530, tor
example, they both extend substantially in the y direction as shown in Figure 5.
Each of the bar portions 536 functions to connect respective elongated portion:; of the
first plurality of elongated portions 530 with respective elongated portions of the
second plurality of elongated portions 534. For example, as shown in Figure 5, two of
the first plurality of elongated portions 530 at the top are connected to two of the
second plurality of elongated portions 534 at the top via a top one of the bar portions
536, and correspondingly two of the first plurality of elongated portions 530 at the
bottom are connected to two of the second plurality of elongated portions 534 at the
bottom via a bottom one of the bar portions 536.
Each of the elongated portions of the second plurality of elongated portions 534 has a
first end and an opposing end opposite to the first end. The first end contacts the base
9

144162
portion 512 at a respective contact point, while the opposing end contacts one of the
bar portions 536.
Each of the elongated portions of the first plurality of elongated portions 530 has one
end contacting a respective bar portion 536, and an opposing end contacting the
payload support portion 518.
The transducer 516 applies a force to the payload support portion 518 in a second
direction substantially orthogonal to the first direction (substantially the direction of
the elongated support portions), for example, in the x-direction as illustrated in Figure
5. Applying the force substantially orthogonal to the direction of the elongated
portions 530 allows the elongated portions 530 to flex at their respective points of
contact with the bar portion 536 and payload support portion 518, and allows the
elongated portions 534 to flex at their respective points of contact with the bar portion
536 and base portion 512.
The flexing of the elongated portions 530 and 534 at their respective points of contact
is illustrated in Figure 6. Figure 5 illustrates the motion mechanism 510 in the
situation where the transducer 516 is not applying a force on the flexure portion 514,
while Figure 6 illustrates the motion mechanism 510 in the situation where the
transducer 516 is applying a force on the flexure portion 514 to the right, or in the -r-x
direction. As can be seen in Figure 6, the elongated portions 530 and 534 fiex at their
contact points. Figure 5 corresponds to the minimum travel state of the payload 520,
while Figure 6 corresponds to the maximum travel state of the payload 520 in the +x
direction.
Returning to Figure 5, the motion mechanism 510 may include a preloaded screw 540
that functions to provide a cornpressive force to the transducer 516. The transducer
516 provides a force to the payload support portion 518 at one end. while the
opposing end of the transducer 516 contacts the preloaded screw. In the case that the
transducer 516 comprises a piezoelectric stack, the compression force from the
10

144162
preloaded screw aids in preventing the piezoelectric stack from coming apart when no
voltage is applied to the stack.
The preloaded screw 540 can be adjusted to provide compression as desired. While a
larger compression aids in preventing the stack from breaking apart, it also reduces
the maximum travel that can be provided to the payload 520.
Preferably the stiffness of the flexure portion 514 is comparable to the stiffness of the
transducer 516. A comparable stiffness allows for a good repeatability in the motion
of the payload 520 driven by the transducer 516, and provides a higher bandwidth
performance. The range of the force of the transducer 516 may be adjusted by-
adjusting the compression force from the preload screw 540. The stiffness of the
flexure portion 514 may be between 1/10 and 4 times the stiffness of the transducer
516, or between 1/10 and 2 times the stiffness of the transducer 516, for example.
Preferably the stiffness of the flexure portion 514 is substantially the same as the
stiffness of the transducer 5 16.
The base portion 512 and the flexure portion 514 may be formed from the same block
of material. In this way the base portion 512 and the flexure portion 514 may be
integral. For example, the base portion 512 and the flexure portion 514 may be
formed from a titanium alloy, aluminum alloy or steel block. The block may be
machined to form the base portion 512 and the flexure portion 514 in an integral
fashion.
The base portion 512 may comprise a ground block, and the ground block may
include one or more spray nozzles 550 thereon to provide a spray towards the payload
support portion 518. For example, if the payload 520 is a cutting tool, the spray
nozzles 550 may provide a spray of air or other gas to blow away chips or o:her debris
formed when the cutting tool cuts into a workpiece.
The motion mechanism 10 may also include a position probe 560 to detect the
position of the payload support portion 518. The position probe 560 provides
feedback when the motion mechanism 510 is controlled to position the payload
11

144162
support portion 518 and its payload 520. The position probe 560 may be at least one
of a capaeitanee gauge, a laser range finder, or an interferometer, for example.
The motion meehanisms 510 may also include a constrained layer 570 that acts to
provide viscoelastic damping to the motion of the payload support portion 518 and
thus the payload 520. This damping reduces overshoot and ringing in the actual
position of the payload 520 relative to the commanded position of the payload when
the payload 520 is driven. The constrained layer 570 may be positioned to fill the
regions between the payload support portion 518, the elongated portions 530 and 534,
and the base portion 512. The constrained layer 570 may comprise a viscoelasiic
material such as polypropylene, for example.
Figure 7 illustrates an embodiment similar to that shown in Figure 5. In the
embodiment of Figure 7, however, the thickness of each of the elongated portions 530
and 534 has a middle portion 580 which is stiffer than its end portions. This may be
accomplished, for example, by having the middle portions 580 be thicker than the end
portions, or by providing that the middle portions are formed of a material which has
a higher stiffness than the material of the end portions. In this embodiment the
rotational stiffness of the flexure 514 is increased.
Figure 4 illustrates a machine tool system 100 according to an embodiment of the
invention which employs a motion mechanism !10, which may be the motion
mechanism 10 with a cutting tool as the payload 20 as described above in Figures 1-3,
or the motion mechanism 510 with a cutting tool as the payload 520 as described
above in Figures 5-7. The machine tool system 100 provides for the machining of a
workpiece (not shown) provided on a workpiecc support 112 such as a rotating drum.
The machine tool system includes a controller unit 1 14 that controls the transducers
40 and 42 (or just 40 in the embodiment of Fig. 3 (see Figs. 1-3) of the motion
mechanism 10, or just 516 in the embodiments of Figures 5-7), and receives feedback
from the position probe 60 or 560 of the motion mechanism 10 or 510. An
input/output data processor 102 provides cutting commands to a digital signal
processing (DSP) unit 104 that supplies a signal to a digital-to-analog (DA)
12

144162
conversion device 106. Voltage amplifier 108 receives a signal from the DA
converter 106 and drives the transducer of the motion mechanism 10 or 510 to direct
the motion of cutting tool payload 20 (see Figs. 1-3 or 5-7). The position probe 60
(see Figs. 1-3) or 560 (see F'igs. 5-7) senses a position of the payload and provides a
signal indicative of the position to a sensor amplifier 1 18. Amplifier 1 18 amplifies
the signal. The amplified signal is directed to analog-to-digital (AS)) converter 120.
Lathe encoder 116 determines the position of the workpiece on the workpicee support
112 and provides a feedback signal to the A/D converter 120. The A/D converter 120
thus provides a feedback signal indicative of the position of the cutting tool and the
position of the workpiece on the workpiece support 112 as output to the digital signal
processing unit 104. The DSP unit 104 provides a processed signal to the
input/output processor 102. The payload 20 may be driven as desired. The machine
tool system may provide motion in addition to the motion mechanism 110. When
machining, the additional motion may be provided in a direction, defined as the
cutting direction, in the nominal plane of the surface of the workpiece. Additional
motion in a direction, defined as the in-feed direction, in and out of the nominal plane
of the surface of the workpiece may also be provided. The motion mechanism 1 10
may be used to provide motion in the cutting direction, in the plane of the surface
orthogonal to the cutting direction, in the in-feed direction, or any combination
thereof.
While the invention has been described in detail and with reference to specific
embodiments thereof, it will be apparent to one skilled in the art that various changes
and modifications can be made therein without departing from the spirit and scope of
the invention. Thus, the breadth and scope of the present invention should not be
limited by any of the above-described exemplary embodiments, but should be defined
only in accordance with the following claims and their equivalents.
13

144162
WHAT IS CLAIMED IS:
1. A motion mechanism comprising:
a payload support portion configured to support a payload;
a ground portion;
a first side portion connected to the payload support portion at a first contact point and
connected to the ground portion at a second contact point;
a second side portion connected to the payload support portion at a third contact point
and connected to the ground portion at a fourth contact point;
a first transducer arranged to provide a force to the first side portion in a first linear
direction when actuated so that the first side portion provides a force to the payload
support portion at the first contact point in a second direction substantially orthogonal
to the first direction; and
a second transducer arranged to provide a force to the second side portion in a third
linear direction when actuated so that the second side portion provides a force to the
payload support portion at the third contact point in a fourth direction substantially
orthogonal to the third direction.
2. The motion mechanism of claim 1, wherein when the first direction and the
third direction are opposite to one another, and the second direction is substantially
the same as the fourth direction.
3. The motion mechanism of claim 1, wherein the contact points comprise a rigid
or semi-rigid material.
4. The motion mechanism of claim 1, wherein the contact points comprise a rigid
or semi-rigid material, and the payload support portion, first and second side portions,
and the ground portion are integral.
14

144162
5. The motion mechanism of claim 1, wherein the contact points, payload
support portion, first and second side portions and the ground portion arc of the same
material.
6. The motion mechanism of claim 5, wherein the contact points, payload
support portion, first and second side portions and the ground portion comprise at
least one of titanium alloy, aluminum alloy, or steel.
7. The motion mechanism of claim 1. wherein when the first transducet is
actuated and provides a force to the first side portion in the first direction, the first
side portion rotates about the second contact point, and when the second transducer is
actuated and provides a force to the second side portion in the third direction, the
second side portion rotates about the fourth contact point.
8. The motion mechanism of claim 7, wherein the first and second side portions
are substantially L-shaped.
9. The motion mechanism of claim 1, wherein the ground portion comprise a
ground block, and the mechanism further comprises:
at least one spray nozzle arranged on the ground block to provide a spray towards the
payload support portion.
10. The motion mechanism of claim 1, further comprising:
a position probe arranged to detect the position of the payload support portion.
1 1. The motion mechanism of claim 10, wherein the position probe is at least one
of a capacitance gauge, a laser range finder, or an interferometer.
12. The motion mechanism of claim 1, further comprising:
a payload attached to the payload support portion, wherein the payload comprises at
least one of a cutting tool or a laser head.
15

144162
13. The motion mechanism of claim 12, wherein the payload comprises a diamond
cutting tool.
14. The motion mechanism of claim 1, further comprising:
a constrained layer between at least parts of the ground portion and the payload
portion configured to provide viscoelastic damping to the motion of the payload
support portion.
15. The motion mechanism of claim 14, wherein the constrained layer comprises
polypropylene.
16. The motion mechanism of claim 1, wherein the first and second transducers
comprise piezoelectric stacks.
17. The motion mechanism of claim 1, wherein the resonant frequency of motion
of the payload support portion is greater than about 4 kHz.
18. The motion mechanism of claim 1, wherein the first transducer and the second
transducer are configured to have opposite polarity with respect to each other.
19. A motion mechanism comprising:
a payload support portion configured to support a payload;
a ground portion;
a first side portion connected to the payload support portion at a first contact point and
connected to the ground portion at a second contact point:
a second side portion connected to the payload support portion at a third contact point
and connected to the ground portion at a fourth contact point; and
a first transducer arranged to provide a force to the first side portion in a first linear
direction when actuated so that the first side portion provides a force to the payload
16

144162
support portion at the first contact point in a second direction substantially orthogonal
to the first direction.
20. A motion mechanism comprising:
a payload support portion configured to support a payload;
a ground portion;
a first side portion connected to the payload support portion at a first contact point and
connected to the ground portion at a second contact point;
a second side portion connected to the payload support portion at a third contact point
and connected to the ground portion at a fourth contact point;
a first transducer arranged to provide a force to the first side portion in a first direction
when actuated so that the first side portion provides a force to the payload a: the first
contact point in a second direction substantially orthogonal to the first direction; and
a spring arranged to provide a bias force to the second side portion in a third direction
so that the second side portion provides a force to the payload at the third contact
point in a fourth direction substantially orthogonal to the third direction.
21. A motion control system comprising:
a workpiece support configured to support a workpiece;
a motion mechanism comprising:
a payload support portion configured to support a payload;
a ground portion;
a first side portion connected to the payload support portion at a first contact point and
connected to the ground portion at a second contact point;
17

144162
a second side portion connected to the payload support portion at a third contact point
and connected to the ground portion at a fourth contact point;
a first transducer arranged to provide a force to the first side portion in a first linear
direction when actuated so that the first side portion provides a force to the payload
support portion at the first contact point in a second direction substantially orthogonal
to the first direction; and
a second transducer arranged to provide a force to the second side portion in a third
linear direction when actuated so that the second side portion provides a force to the
payload support portion at the third contact point in a fourth direction substantially
orthogonal to the third direction; and
a controller unit configured to control the transducers to control the motion of the
cutting tool to cut the workpiecc.
22. A motion mechanism comprising:
a base portion;
a flexure portion comprising:
a payload support portion configured to support a payload;
a first plurality of elongated portions extending substantially in a first direction and
contacting the payload support portion; and
wherein the flexure portion contacts the base portion; and
a transducer arranged to provide a force to the payload support portion in a second
direction when actuated, the second direction substantially orthogonal to the first
direction.
23. The motion mechanism of claim 22, wherein the flexure portion further
comprises:
18

144162
at least one bar portion contacting respective of the first plurality of elongated
portions at an end of the respective first plurality of elongated portions opposite to an
end contacting the payload support portion; and
a second plurality of elongated portions extending substantially in the first direction,
each elongated portion of the second plurality of elongated portions having a first end
and an opposing second end, the first end contacting the base portion via a respective
contact point and the opposing end contacting a respective at least one bar portion.
24. The motion mechanism of claim 23, wherein each of the elongated portions
has a middle portion which is stiffer than its end portions.
25. The motion mechanism of claim 23, wherein the transducer provides the force
to the payload support portion via a first transducer end, the mechanism further
comprising:
a preloaded screw contacting and providing a compression force to a second
transducer end opposite the first transducer end.
26. The motion mechanism of claim 22, wherein the stiffness of the flexure
portion is substantially the same as the stiffness of the transducer.
27. The motion mechanism of claim 22, wherein the base portion and flexure
portion are of the same material.
28. The motion mechanism of claim 27, wherein the base portion and flexure
portion comprise at least one of titanium alloy, aluminum alloy, or steel.
29. The motion mechanism of claim 22, wherein the base portion comprise a
ground block, and the mechanism further comprises:
at least one spray nozzle arranged on the ground block to provide a spray towards the
payload support portion.
30. The motion mechanism of claim 22, further comprising:
19

144162
a position probe arranged to detect the position of the payload support portion.
31. The motion mechanism of claim 30, wherein the position probe is at least one
of a capacitance gauge, a laser range finder, or an interferometer.
32. The motion mechanism of claim 22, further comprising:
a payload attached to the payload support portion, wherein the payload comprises at
least one of a cutting tool or a laser head.
33. The motion mechanism of claim 32, wherein the payload comprises a diamond
cutting tool.
34. The motion mechanism of claim 22, wherein the transducer comprises a
piezoelectric stack.
35. The motion mechanism of claim 22, wherein the resonant frequency of motion
of the payload support portion is greater than about 4 kHz.
36. The motion mechanism of claim 22, wherein the stiffness of the flexure
portion is between 0.1 and 4 times the stiffness of the transducer.
37. The motion mechanism of claim 36, wherein the stiffness of the flexure
portion is between 0.1 and 2 times the stiffness of the transducer.
38. A motion control system comprising:
a workpiece support configured to support a workpiece;
a motion mechanism comprising:
a base portion;
a flexure portion comprising:
a payload support portion configured to support a payload;
20

144162
a first plurality of elongated portions extending substantially in a first direction and
contacting the payload support portion, wherein the flexure portion contacts the base
portion; and
a transducer arranged to provide a force to the payload support portion in a second
direction when actuated, the second direction substantially orthogonal to the first
direction; and
a controller unit configured to control the transducers to control the motion of the
cutting tool to cut the workpiece.
39. The motion control system of claim 38, wherein the controller is further
configured to control the motion mechanism to provide motion in a direction in a
plane of a surface of the workpiece and in a direction perpendicular to the plane of the
surface of the workpiece.

A motion mechanism is described. In one embodiment, the motion mechanism includes a base portion, a flexure portion, and a transducer. The flexure portion includes a payload support portion configured to support a payload, a first plurality of elongated portions extending substantially in a first direction and contacting the payload support portion, wherein the flexure portion contacts the base portion. The transducer is arranged to provide a force to the payload support portion in a second direction when actuated, the second direction substantially orthogonal to the first direction. Other embodiments of the motion mechanism arc also described.