WO2012045739A1

WO2012045739A1 - Guide rail for rectilinear motion

Info

Publication number: WO2012045739A1
Application number: PCT/EP2011/067306
Authority: WO
Inventors: Filip De Coninck; Wim Desmet; Bert Pluymers
Original assignee: Katholieke Universiteit Leuven
Priority date: 2010-10-04
Filing date: 2011-10-04
Publication date: 2012-04-12
Also published as: GB201016635D0

Abstract

A device (100) is described for providing rectilinear motion based on a circular shaped bearing guide rail (1). The system uses a rotating circular sharped guide rail controlled by a rotational motion actuator system (6) during linear motion and thereby improves the frictional conditions of the bearings (2, 4) in the rectilinear motion system.

Description

Guide rail for rectilinear motion

Field of the invention

The invention relates to the field of motion mechanics. More particularly, the present invention relates to methods and systems for providing rectilinear motion, as well as components used therein.

Background of the invention

Mechanical systems for controlled and/or automated movement of objects have obtained a lot of interest in the past. One type of movements that often needs to be implemented is a rectilinear movement. A number of solutions for providing accurate rectilinear movement have been provided, e.g. based on threaded drives and based on bearing-based translation systems.

Bearing-based translation systems for rectilinear systems can make use of different types of bearings.

Ball bearings systems typically use metal or ceramic balls in a cage and rolling through a motion path. These are especially suitable for translations implying a small dynamic motion. For small displacements and for high dynamic motion, the ball bearings have been found to be less suitable as the balls do not roll but slide in a small contact zone.

This results in wearing out the balls and rail unevenly and damaging of the system.

Another type of bearing system that can be used is a slider bearing using a material contact with dry friction. This type of friction features stick-slip and a speed dependent friction coefficient. At low speed, the friction coefficient can become too high, again resulting in wear and damaging of the system.

Summary of the invention

It is an object of embodiments of the present invention to provide good systems and methods for providing rectilinear motion. It is an advantage of embodiments according to the present invention that systems and methods for providing rectilinear motion are obtained that suffer less from friction or wear. It is an advantage of embodiments according to the present invention that rectilinear motion of a mass supported by bearings with improved frictional conditions of the bearings is obtained. It is an advantage of embodiments according to the present invention that systems and methods can be obtained for providing rectilinear motion, wherein a variety of bearings can be used, such as for example ball bearings, hydrodynamic bearings or slide bearings.

It is an advantage of embodiments of the present invention that the relative surface velocity is not determined only by the linear motion actuator, thus allowing to obtain a desirable low friction in the bearings even for slow linear speeds, reversing motion or small displacements.

The above objective is accomplished by a method and device according to the present invention.

The present invention relates to a rectilinear motion system for moving a mass comprising a circular shaped guide rail having an axis, a first bearing module supporting the circular shaped guide rail and enabling at least a rotational degree of freedom of the guide rail, said first bearing module being connectable to a reference body, a second bearing module enabling at least a rotational degree of freedom for the guide rail, said second bearing module being connectable to the mass and supported by the guide rail, at least one of the first bearing module or the second bearing module enabling a linear degree of freedom of the guide rail along the axis, the system furthermore comprising a rotational motion actuator system which is connected to the guide rail for inducing an angular displacement of the guide rail around its axis for modifying the relative surface speed conditions in the at least one of the first bearing module or the second bearing module. It is an advantage of embodiments of the present invention that wear and friction in the bearing systems can be reduced or even avoided. It is an advantage of embodiments of the present invention that the rotational actuator system can be used for achieving a high relative surface velocity, independent of the translational actuator system. For slider bearings, this velocity may be for example between 0.05 m/s and 5 m/s, advantageously in the range 0.2 m/s to 1 m/s. For circular ball bearings, this velocity may for example be between 0.01 m/s and 3 m/s, advantageously between 0.05 m/s and 0.5 m/s. For hydrodynamic bearings the velocity may be between 20 and 10000 RPM, advantageously between 50 and 3000 RPM. Values outside the given ranges may also be applicable and may for example apply to special designs of the different bearing types, like very small or very large systems.

The second bearing may be adapted for providing the linear degree of motion of the guide rail, along its axis. The mass may be moved in the rectilinear direction by a linear actuator system, which is independent from the rotational motion actuator system. It is an advantage of embodiments of the present invention that existing linear actuator systems for actuating the motion in the linear direction can be used, e.g. resulting in the possibility for using existing components or upgrading existing systems.

The circular shaped guide rail may be a solid rod or a hollow tube.

The surface of the guide rail may be a grinded surface, polished surface or coated surface for inducing low friction.

Each of the bearing modules may be any of a slider bearing, a hydrodynamic bearing or a ball bearing. It is an advantage of embodiments according to the present invention that a variety of types of bearings can be used, including a hydrodynamic bearing type.

At least the first bearing module or the second bearing module may be adapted for providing linear displacements between Ιμιη and lm and at linear speeds between lmm/s and lOm/s. It is an advantage of embodiments according to the present invention that a wide range of displacements and displacement speeds can be obtained with the systems. The system may be adapted for providing linear displacements between lnm and lm and/or for providing linear displacements at linear speeds between lnm/s and lOm/s.

At least one of the first bearing module or the second bearing module may be adapted for providing linear displacements with dynamically reversing motion paths like in shaker table test rigs. The reference body may be the world reference, building floor or wall or machine frame.

The rotational motion of the guide rail may be adapted for providing complete elimination of stick-slip conditions in the friction contact between the at least one of the first bearing module or the second bearing module on the one hand and the guide rail on the other hand for a slider bearing application.

The rotational motion actuator system may be of any or a combination of an electrical, electro-magnetic, pneumatical, hydraulical, or mechanical actuator system. The rotational motion actuator system may have a fixed or variable speed control system.

The speed control system may be or may be part of any of an open or closed loop type. It is an advantage of embodiments of the present invention that the system can be provided with a feedback loop allowing tuning the system to selected conditions. The speed control system may be adapted for controlling the friction coefficient in the contact between the guide rail and the at least one of the first bearing or the second bearing, thereby controlling the damping of the rectilinear motion.

The speed control system may be adapted for controlling the bearing radial stiffness in a contact between the guide rail and the at least one of the first bearing or the second bearing, for controlling dynamics and resonances of the mass.

The rotational motion actuator system may be adapted for inducing an induced angular motion being discontinuous and reversing, with a maximum angle of rotation of the guide rail for example in the range 30° to 180 °, but possibly as small as 1°. The first bearing may be part of the rotational motion actuator system.

The system furthermore may comprise at least a second circular shaped guide rail, a third bearing module supporting the second circular shape guide rail and enabling at least a rotational degree of freedom of the second guide rail, said third bearing module being connectable to a reference body, a fourth bearing module enabling at least a rotational degree of freedom for the second guide rail, said fourth bearing module being connectable to the mass and supported by the second guide rail, wherein at least one of the third bearing module or the fourth bearing module enables a linear degree of freedom of the second guide rail along the axis, the first circular shaped guide rail and the second circular shaped guide rail being configured so as to constrain the rotational degree of freedom in the bearing modules. It is an advantage of embodiments according to the present invention that masses providing a high load can be accurately supported and accurately positioned.

The present invention also relates to the use of a system as described above for providing recti-linear motion of a mass. The use may be for controlling the dynamics and resonances of the mass during the recti-linear motion of the mass.

In one aspect, the present invention relates to a system comprising a circular shaped guide rail, a rotational motion actuator system and two bearing modules, one of which is attached to the non-moving reference body for the rectilinear motion system and one of which is attached to the linear moving mass of the rectilinear motion system, wherein rotation of the guide rail is induced by a rotational actuator system causing the relative surface speed between the bearings and the guide rail to be high, thereby enabling the use of hydrodynamic and ball bearing modules or improving the behavior of the slider bearing modules.

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Brief description of the drawings

Figure 1 schematically shows the components of an exemplary system according to an embodiment of the present invention.

Figure 2 schematically shows another exemplary system using an electrodynamic shaker for the linear motion, according to an embodiment of the present invention. Figure 3 shows results of a validation experiment for a system as shown in figure 3, wherein shaker force measurements are illustrated for following situations : first the shaker oscillation is started (B), then the rotation is started(C), then the rotation is stopped(D), then the shaker is stopped(E).

Figures 4 and 5 show a detail of the force signal when the guide rail is not rotating respectively rotating, illustrating features and advantages of embodiments according to the present invention.

Figure 6 shows a time frequency analysis of the force signal during a validation experiment as described in FIG. 3, illustrating features and advantages of embodiments according to the present invention.

Figure 7 shows the bearing module acceleration during the validation experiment as described in FIG. 3, wherein a closed loop acceleration control is used for the shaker at a level of 0.8g, illustrating features and advantages of embodiments according to the present invention.

Figure 8 and Figure 9 show a detail of the acceleration when the guide rail is not rotating respectively is rotating, illustrating features and advantages of embodiments according to the present invention.

Figure 10 shows a time frequency analysis of the acceleration signal during a validation experiment as described in FIG. 3, illustrating features and advantages of embodiments according to the present invention.

Figure 11 shows the three bearing types that can be used with the rotating bar guide rail in a system according to the present invention, wherein of the different bearing types are a (left) slider type bearing with friction coefficient behaviour as function of sliding speed, a (middle) ball-type bearing with inclined motion paths and recirculating ball design, and a (right) hydrodynamic bearing with cross-section.

The drawings are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.

Any reference signs in the claims shall not be construed as limiting the scope.

In the different drawings, the same reference signs refer to the same or analogous elements. Detailed description of illustrative embodiments

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Where in embodiments of the present invention reference is made to rectilinear movement or rectilinear motion, reference is made to movement or motion of a mass or object to be displaced along a path characterized by a straight line.

In a first aspect, the present invention relates to a rectilinear motion system for moving masses. Embodiments according to the present invention can advantageously be used in systems wherein slow linear speeds, reversing motion or small displacement are required. Different standard and optional features of the system are indicated with reference to figure 1. According to embodiments of the present invention, the rectilinear motion system 100 according to embodiments of the present invention comprises a circular shaped guide rail 1 having an axis. This guide rail will be rotated during use. Through the rotation of the guide rail, the operating conditions of the bearing modules are changed, which improves their behaviour. The circular shaped guide rail 1, which can be a solid rod or a hollow tube, may be optionally be treated for low friction trough grinding, polishing or coating. The effect of the surface finish and the rotation of the bar are complementary. It may be made of any suitable material such as a metal, polymer, composite or ceramic material. The system also comprises a first bearing module 2 supporting the circular shaped guide rail 1 and enabling at least a rotational degree of freedom of the guide rail 1. The rotational degree of freedom provides rotation of the guide rail around its axis. The first bearing module 2 also is connectable to a reference body 3. The reference body may be the world reference, building floor or wall or machine frame. With respect to some prior art systems, it could be considered that the bearing replaces the conventional clamping devices of the guide rail and thereby enables it to rotate. Where reference is made to the first bearing module 2 connectable to a reference body, this may include a single bearing module 2 connectable to a reference body or a set of first bearing modules 2 connectable to a reference body.

The system furthermore comprises a second bearing module 4 enabling at least a rotational degree of freedom for the guide rail 1, i.e. also providing the possibility for the guide rail to rotate around its axis. The second bearing module 4 is connectable to the mass 5 and supported by the guide rail 1. According to embodiments of the present invention, at least one of the first bearing module 2 or the second bearing module 4 are enabling a linear degree of freedom of the guide rail along the axis. In other words, at least one of the bearing modules allows to induce the translational movement of the mass. In one embodiment, at least the second or only the second bearing module may allow translational degree of freedom for the guide rail. It can for example be used for linear displacements as small as one nanometer at linear speeds as small as 1 nanometer per second. It can for example also be used for linear displacements with dynamically reversing motion paths like in shaker table test rigs. An example thereof is illustrated in figure 2. Where reference is made to the second bearing module 4 connectable to the mass to be moved, this may include a single bearing module 4 connectable to the mass to be moved or a set of second bearing modules 4 connectable to a mass to be moved.

The bearing systems of embodiments of the present invention can make use of different types of bearing systems.

In one embodiment, at least one of the bearing systems is a ball bearing system. Such a system, wherein metal or ceramic balls are provided in a cage and are rolling through a motion path, can in embodiments of the present invention advantageously be used as the rotation of the guide bar causes the balls to circulate at high speed. This results in an evenly wearing out of both the balls and the rails.

In one embodiment, at least one of the bearing systems is a hydrodynamic bearing. In hydrodynamic bearings, e.g. based on oil or air, the load supporting pressure is generated by a high speed motion of a shaft or surface relative to an inclined bearing surface. The fluid is then compressed in the bearing, e.g. through a particular form, such as a conic gap form, and high relative speed. The type of bearings advantageously can be used in embodiments of the present invention, due to the high relative speed induced by the rotating guide bar.

In one embodiment, at least one of the bearing systems is a slider bearing using a material contact with dry friction. In embodiments according to the present invention, advantageously use can be made of the fact that he sliding surface can be kept at high speeds therefore forcing the friction coefficient to a low value, related to that high relative surface velocity. Examples of these different types of bearing systems are illustrated with reference to Figure 11. Figure 11 illustrates different components of the systems. In the examples shown, the slider type bearing uses a hollow guide rail and bearing systems comprising a bearing housing 1101, and a bearing liner. Figure 11 also indicates, for the slider type bearing, the friction as function of sliding speed. In another part, Figure 11 illustrates a ball-bearing type bearing, with balls in an inclined motion path 1111 and recirculating balls 1112 for bringing the bearing balls back to their original position. In yet another part, Figure 11 illustrates a hydrodynamic-type bearing, with a non-contact hydrodynamic bearing 1121. For the ball-bearing type and hydrodynamic type bearing, in the shown examples use is made of a full, solid guide rail 1. Within the same embodiment, use can be made of the same type of bearing systems or different types of bearing systems. Such types of bearings are as such known to the person skilled in the art and therefore not further discussed in detail in the present application.

The system 100 furthermore comprises a rotational motion actuator system

6 which is connected to the guide rail 1 for inducing an angular displacement of the guide rail 1 around its axis for modifying the relative surface speed conditions in the at least one of the first bearing module 2 or the second bearing module 4. The rotational motion actuator system may be of electric, pneumatic, hydraulic, mechanical, ... type and may comprise a fixed or variable speed control system. The latter will allow control of the friction coefficient and damping in slider applications and control of the bearing radial stiffness in hydrodynamic applications. Both effects are additional benefits of the invention. This control may be done with open or closed loop control architecture, where the latter will require an additional feedback sensor for force, speed or position. In certain applications it is not necessary for the present invention that the rotation of the guide rail is continuous. The maximum angle of rotation of the guide rail induced by the rotational motion actuator system can be as small as one degree and the induced angular motion may be discontinuous and reversing. The rotation of the guide rail 1, induced by the rotational motion actuator system 6 causes the relative surface speed between the bearings (2,4) and the guide rail 1 to be high, thereby enabling the use of hydrodynamic and ball bearing modules or improving the behaviour of slider bearing modules (2,4). The rotational motion of the guide rail may lead to the complete elimination of stick-slip conditions in the friction contact of the bearing module 4 and the guide rail 1 for a slider bearing application. Stick-slip is an interaction between the friction contact and the flexibility in the actuator system. Energy is stored in the flexibility during the stick-phase and the force level builds up. When the static friction force value is exceeded, the contact conditions change to sliding friction with generally a lower dynamic friction coefficient. The energy that was stored in the flexibility is released, resulting in a speed increase. The inertia then causes the force in the flexibility to decrease below the maximum friction force and the speed decreases until the friction contact is static (stick) again and the cycle repeats. For slider applications, reciprocating motion paths inherently contain a stick phase. The rotating guide rail 1 according to embodiments of the present invention forces the sliding contact to have a relative surface speed (slip) regardless of the translational (longitudinal) motion and therefore reduces or eliminates the stick-slip effect. The stick-slip effect may not be completely eliminated in some of the embodiments due to a combination of slow rotation speeds, small angle intermitted rotation or a highly flexible rotational actuator system 6, but is at least reduced compared to the situation whereby no rotation is implemented.

In particular embodiments, the system also may comprise a linear actuator system for moving the mass in the rectilinear direction. The system typically may be independent from the rotational motion system. One example of such a linear actuator system may be an electrodynamic shaker.

In some embodiments, the rectilinear motion system also may comprise a plurality of rotation guide rails and corresponding bearing systems, which are used in parallel to constrain the rotational degree of freedom of the bearing module and the mass and to support high loads. The latter is especially advantageous for improving stability, stiffness or for moving large masses. By way of illustration, embodiments of the present invention not being limited thereto, an example of a system for rectilinear motion according to an embodiment of the present invention is described and experimental results are discussed below . An experiment was performed on a setup similar to that of Figure 2 using two slider bearing modules 2 fixed to the world reference 3, one slider bearing module 4 attached to an electrodynamic shaker 7 and an electric motor 6 attached to the circular guide rail 1. The electrodynbamic shaker thereby was part of a closed loop sinusoidal amplitude control system. The axial motion of the guide rail was blocked. The shaker force applied on the bearing and the resulting acceleration of the bearing module was measured. The requested motion was a constant sinusoidal acceleration of the bearing module 4, controlled by a closed loop algorithm.

The force measurement of the experiment is given in Figure 3. Initially the rail was not rotating (A), then the shaker was started up (B), then the rail rotation actuator was activated (C) and the rail was rotating, then the rotation was stopped (D) and finally the shaker was stopped (E). A clear drop (at t= 70s, point C) in driving force was noticed when the rotation was activated, which indicates a significant reduction in friction force. When zooming in on the time trace, a clear distortion of the force signal (non-sinusoidal) in the normal (non-rotating) operation (B-C & D-E) was noticeable as is shown in Figure 4. The shape of the force time trace was not sinusoidal. Instead, an asymmetric shape was observed as the peak force was achieved earlier than the middle of the curve, as indicated by the dash-dotted line. Starting at zero force (and maximum sliding speed) indicated by point 41, the force increased to the maximum indicated by point 43 (and zero sliding speed) with an intermediate slope change at point 42 due to the changing friction coefficient in function of the changing sliding speed. The maximum force was determined by the static friction coefficient. In the force decreasing part first an almost constant slope was observed between point 43 and 44, followed by a slope change at point 44 towards the zero force point. The complex shape of the curve was the result of the interaction between the shaker system inertia, the stinger stiffness and the bearing module friction as the electrodynamic force that is applied was purely sinusoidal. A much lower force was necessary when the guide rail was rotating as is shown in Figure 5. Here the global shape of the curve was far more sinusoidal and symmetric. The force signal however was more noisy than when the guide rail was not rotating. This effect is due to the fact that the guide rail and bearings were already used and worn. In addition, the guide rail had a surface finish of the lowest/cheapest quality. This illustrates that embodiments of the present invention work for every available quality of components and remains valid throughout the lifetime of the components. In order to show more clearly the difference in signal distortion, the time frequency analysis (Figure 6) was used. Here the X-axis is the time axis, the Y-axis is the frequency axis and the map indicates the spectral amplitude. When the shaker is oscillating, the fundamental frequency and the higher order harmonics were present. A much lower level of the main driving force (fundamental frequency) and of the higher harmonics was observed when the rail was rotating (C-D). Above the 4th harmonic, no higher orders are noticeable anymore in the rotating condition, whereas in the non-rotating operation (B-C & D-E) up to 19 harmonics are visible. The acceleration measurement (Figure 7) shows little influence, because a closed loop acceleration control system with harmonic estimator was used. Comparison of the time traces (Figure 8 and Figure 9) however shows a clear difference in harmonic content. This was confirmed by the time-frequency analysis (Figure 10) where the fundamental frequency amplitude was almost unchanged, as this is closed loop controlled, but the higher harmonics are significantly reduced due to the rotation of the rail.

Claims

1. A rectilinear motion system (100) for moving a mass (5) comprising

- a circular shaped guide rail (1) having an axis,

- a first bearing module (2) supporting the circular shaped guide rail (1) and enabling at least a rotational degree of freedom of the guide rail (1), said first bearing module (2) being connectable to a reference body (3),

- a second bearing module (4) enabling at least a rotational degree of freedom for the guide rail (1), said second bearing module (4) being connectable to the mass (5) and supported by the guide rail (1),

at least one of the first bearing module (2) or the second bearing module (4) enabling a linear degree of freedom of the guide rail along the axis,

the system (100) furthermore comprising

- a rotational motion actuator system (6) which is connected to the guide rail (1) for inducing an angular displacement of the guide rail (1) around its axis for modifying the relative surface speed conditions in the at least one of the first bearing module (2) or the second bearing module (4).

2. A system (100) according to claim 1, wherein the system comprises a linear actuator system (7) for moving the mass (5) in the rectilinear direction, the linear actuator system (7) being independent from the rotational motion actuator system (6).

3. A system (100) according to any of the previous claims wherein the circular shaped guide rail (1) is a solid rod or a hollow tube.

4. A system (100) according to any of the previous claims wherein the surface of the guide rail (1) is a grinded surface, polished surface or coated surface for inducing low friction.

5. A system (100) according to any of the previous claims wherein each of the bearing modules (2, 4) is any of a slider bearing, a hydrodynamic bearing or a ball bearing.

6. A system (100) according to any of the previous claims wherein at least the first bearing module (4) or the second bearing module (4) is adapted for providing linear displacements between Ιμιη and lm and at linear speeds between lmm/s and lOm/s.

7. A system (100) according to any of the previous claims wherein at least one of the first bearing module (2) or the second bearing module (4) is adapted for providing linear displacements with dynamically reversing motion paths like in shaker table test rigs.

8. A system (100) according to any of the previous claims wherein the reference body (3) is the world reference, building floor or wall or machine frame.

9. A system (100) according to any of the previous claims wherein the rotational motion of the guide rail (1) is adapted for providing complete elimination of stick- slip conditions in the friction contact between the at least one of the first bearing module (2) or the second bearing module (4) on the one hand and the guide rail (1) on the other hand for a slider bearing application.

10. A system (100) according to any of the previous claims, wherein the rotational motion actuator system (6) is of any or a combination of an electrical, electro- magnetical, pneumatical, hydraulical, or mechanical actuator system.

11. A system (100) according to any of the previous claims, wherein the rotational motion actuator system (6) comprises a fixed or variable speed control system.

12. A system (100) according to claim 11, wherein the speed control system is or is part of any of an open or closed loop type.

13. A system (100) according to any of claims 11 or 12, wherein the speed control system is adapted for controlling the friction coefficient in the contact between the guide rail (1) and the at least one of the first bearing (2) or the second bearing (4), thereby controlling the damping of the rectilinear motion.

14. A system (100) according to any of claims 11 or 12, wherein the speed control system is adapted for controlling the bearing radial stiffness in a contact between the guide rail (1) and the at least one of the first bearing (2) or the second bearing (4), for controlling dynamics and resonances of the mass (5).

15. A system (100) according to any of the previous claims wherein the rotational motion actuator system (6) is adapted for inducing angular motion being discontinuous and reversing and having an angle of rotation of the guide rail (1) between 30° and 180°.

16. A system (100) according to any of the previous claims wherein the first bearing (2) is part of the rotational motion actuator system (6).

17. A system (100) according to any of the previous claims, the system (100)

furthermore comprising

- at least a second circular shaped guide rail,

- a third bearing module supporting the second circular shape guide rail and enabling at least a rotational degree of freedom of the second guide rail, said third bearing module being connectable to a reference body,

- a fourth bearing module (4) enabling at least a rotational degree of freedom for the second guide rail, said fourth bearing module being connectable to the mass (5) and supported by the second guide rail,

wherein at least one of the third bearing module or the fourth bearing module enables a linear degree of freedom of the second guide rail along the axis, the first circular shaped guide rail and the second circular shaped guide rail being configured so as to constrain the rotational degree of freedom in the bearing modules.

18. Use of a system according to any of claims 1 to 16 for providing recti-linear motion of a mass.

19. Use according to claim 18 for controlling the dynamics and resonances of the mass during the recti-linear motion of the mass.