Control device, in particular for an aircraft, comprising an integrated force feedback device

Abstract

Control device (20), in particular of an aircraft, comprising at least one control handle (21) secured to a control lever (24) movable along a displacement stroke and at least one force feedback device (22) capable of generating a resistive or driving force on said control lever (24) over at least part of the displacement stroke, the force feedback device (22) comprising at least one main casing (23), characterized in that the force feedback device (22) comprises: - a movable magnetic element (25) movable in the main casing (23); and - at least one first fixed magnetic element (26, 27) located at one end of the displacement stroke of the control lever (24) and intended to cooperate with the movable magnetic element (25) in an end-of-stroke zone of the control lever (24). Figure for abstract: [Fig 4B]

Description

Title of the invention: Control device, in particular for an aircraft, comprising an integrated force feedback device Technical field of the invention

[0001] The present invention relates to the field of control devices requiring integrated force feedback.

[0002] More particularly, the invention relates to a piloting device used by the pilot of an aircraft, in particular an active stick comprising integrated force feedback to assist the pilot. State of the prior art

[0003] In aircraft, it is known to use mechanical springs in order to transmit return forces to the piloting devices.

[0004] Indeed, for piloting safety, it is necessary for the pilot to perceive mechanical feedback at the piloting device. The signaling systems in the cockpit of the aircraft may not be sufficient to provoke a sufficiently rapid reaction from the pilot when faced with unforeseen events during flight. The piloting sensations are much better on the piloting device incorporating force feedback, also called “haptic feedback”.

[0005] It is known to equip control devices with passive mechanical systems, such as spring systems.

[0006] In this respect, reference may be made to [Fig. 1] which represents a control device 1 comprising a control lever 2 secured to a lever 2a which can rotate about an axis AL. The lever 2 further comprises a stop 2b secured to the lever 2a.

[0007] The control device 1 further comprises two force feedback devices 3 capable of generating a resistive force upon contact with the stop 2b of the lever 2.

[0008] Each of the force feedback devices 3 comprises a casing 4, a pusher 5 sliding in said casing 4 and connected to the bottom 4a of the casing by a mechanical spring 6. The mechanical spring 6 here forms a force feedback at the end of the lever's travel.

[0009] When the lever 2 pivots around the axis of rotation A1, the stop 2b comes into contact with the pusher 5 of one of the force feedback devices 3, which translates inside the casing 4 and compresses the mechanical spring 6, generating a resistive force on the lever 2.

[0010] However, mechanical spring solutions are particularly bulky and do not allow complex force laws to be achieved, such as negative or very low stiffnesses with a high preload.

[0011] Furthermore, mechanical spring solutions require additional guidance systems to those already existing in a control device.

[0012] By "force law" is meant the generation of a resistive force opposing the force exerted on the control device or of a driving force adding to the force exerted on the control device. Statement of the invention

[0013] The present invention therefore aims to overcome the aforementioned drawbacks.

[0014] The objective of the invention is to achieve better compactness and to simplify the manufacture and assembly of a force feedback device capable of generating a resistive or driving force, while offering a capacity to produce more complex force laws, or even laws that cannot be produced with conventional mechanical springs, such as negative or very low stiffnesses with a high preload.

[0015] The subject of the invention is a control device, in particular for an aircraft, comprising at least one control stick or joystick secured to a control lever movable along a displacement path and at least one force feedback device capable of generating a resistive or driving force on said control lever over at least part of the displacement path.

[0016] The force feedback device comprises at least one main casing.

[0017] The force feedback device comprises: - a movable magnetic element in the main casing; and - at least one first fixed magnetic element located at one end of the travel of the control lever and intended to cooperate with the mobile magnetic element in an end-of-travel zone of the control lever, in particular so as to generate the resistive or driving force.

[0018] The force feedback device forms a magnetic force feedback device avoiding having parts in contact to perform the force feedback, unlike devices using mechanical springs. This makes it possible to reduce the wear and fatigue of the constituent elements of the force feedback device and thus to reduce the variation in performance over time.

[0019] The force feedback device is integrated over at least part of the travel of the control lever so as to create an attractive or repulsive force.

[0020] The control device thus comprises a mechanical path configured to prevent the movement of the control lever, either in translation or angularly depending on the embodiment, from being completely free.

[0021] The control lever may be, for example, a throttle lever, allowing the activation of a thrust reversal, the increase of the thrust of the engines, and generally, any control lever requiring force feedback.

[0022] However, provision could be made to maintain the mechanical springs in the event of failure of the magnetic force feedback device.

[0023] Thanks to the force feedback device integrated into the control device, the driving sensations are restored, which increases safety.

[0024] The force feedback device makes it possible to limit accidental movements of the lever and its displacement under load.

[0025] When using the force feedback device in a throttle, this prevents the throttle from remaining in a given position for too long to limit the risk of forgetting.

[0026] Preferably, the movable magnetic element is not in contact with the fixed magnetic elements.

[0027] Such a force feedback device makes it possible to improve the stability of the force law over time by the absence of contact at the level of the force zones.

[0028] Advantageously, the mobile magnetic element and / or the fixed magnetic element comprises at least one permanent magnet.

[0029] Preferably, the force feedback device is configured to generate force feedback over at least part of the movement travel of the control lever, in particular over end-of-travel zones of the lever of the control device.

[0030] Alternatively, the force feedback device is configured to generate force feedback over the entire travel of the lever of the control device.

[0031] According to one embodiment, the main casing extends along a linear segment and internally delimits a guide rail and in which lever of the control device is movable in translation inside said guide rail between two end-of-travel zones.

[0032] According to one embodiment, the control lever is movable in rotation around an axis of rotation according to an angular displacement travel between two end-of-travel zones.

[0033] According to one embodiment, the movable magnetic element is integral with the control lever and the casing extends along an angular segment and internally delimits a main angular guide rail in which the control lever is angularly movable along an angular range extending between two end-of-travel zones, preferably between -90° and 90°.

[0034] Such a solution is particularly advantageous because there is no contact between the lever and the main guide rail. Indeed, the role of the main guide rail is to channel the field of the moving magnet in order to have more stable performance. There is therefore an air gap between the moving magnet and said rail.

[0035] The force feedback device generates the angular displacement of the movable magnetic element in the casing, and therefore the angular displacement of the lever and thus the movement of the lever of the control device over a defined angular range between two end-of-travel zones.

[0036] According to one embodiment, the mobile magnetic element comprises a single magnet extending over an angular range, for example between 5° and 15°.

[0037] Advantageously, the force feedback device comprises a second casing angularly spaced from a first side of the main casing by a non-zero circumferential distance and comprising the first fixed magnetic element.

[0038] This allows the transition from zero torque to resistive torque to be made as abruptly as possible, allowing the pilot to clearly identify when the control lever changes from one angular range to the other.

[0039] Preferably, the first fixed magnetic element comprises two facing permanent magnets spaced apart by a first non-zero air gap and forming a first secondary guide rail for the mobile magnetic element.

[0040] Advantageously, the force feedback device comprises a third casing angularly spaced from a second side of the main casing by a non-zero circumferential distance and comprising a second fixed magnetic element.

[0041] Preferably, the second fixed magnetic element comprises two facing permanent magnets spaced apart by a second non-zero air gap and forming a second secondary guide rail for the mobile magnetic element.

[0042] The first air gap is, for example, equal to the second air gap. Alternatively, one could provide that the first air gap is different from the second air gap. The air gap impacts the magnetic force. One can choose to modify it if one desires different levels of haptic feedback for the pilot in the two end-of-travel zones.

[0043] It would also be possible to provide first magnetic elements that are more or less powerful than the second magnetic elements.

[0044] The magnets of the first fixed magnetic element extend over an angular range of, for example, between 5° and 15°, and the magnets of the second fixed magnetic element extend over an angular range of, for example, between 5° and 15°.

[0045] Having two sides equipped with fixed magnetic elements makes it possible to balance the forces exerted on the lever of the control device.

[0046] Indeed, having a single fixed magnetic element on one side would not allow the lever of the control device to be pushed to the other end-of-travel zone.

[0047] Preferably, the main casing, and therefore the main guide rail, is made of magnetic material.

[0048] Generally, the polarity of the constituent materials of the main guide rail, the movable magnetic element and the fixed magnetic elements is chosen so that the displacement induced by the moving magnetic element is in a direction of attraction or repulsion.

[0049] In other words, the magnetic elements can be active or passive.

[0050] By way of non-limiting example, the materials constituting the movable magnetic element have a first polarity, the materials constituting the main guide rail have a second polarity, the materials constituting the first fixed magnetic elements have a third polarity and the materials constituting the second fixed magnetic elements have a fourth polarity.

[0051] For example, the first polarity is different from the second polarity to generate an attractive force and the first polarity is identical to the third polarity and the fourth polarity to generate a resistive force.

[0052] Alternatively, a structural inversion could be provided in which the movable magnetic element comprises two facing magnets spaced apart by a non-zero air gap and the first fixed magnetic element and the second fixed magnetic element each comprise a single permanent magnet intended to cooperate with the air gap between the two magnets of the movable magnetic element. Thus, said air gap forms a rail for receiving the fixed magnetic elements. However, although such an inversion is possible, it may increase the inertia of the movable part, i.e., of the handle.

[0053] Preferably, the control lever is located in the extension of the control handle and integral in rotation with a control member. Alternatively, it could be provided that the control handle is offset from the control lever.

[0054] According to another embodiment, the control lever comprises a stop and in which the force feedback device comprises a shaft or pusher movable in translation in the casing along an extension axis of said casing and intended to be in contact with the stop of the control lever in an end-of-travel position.

[0055] For example, the casing has the shape of a conical cylinder.

[0056] Advantageously, the force feedback device comprises a second fixed magnetic element secured to the casing, said first and second fixed magnetic elements being arranged opposite each other at each end of said casing, the fixed magnetic elements and the mobile magnetic element cooperating by being placed close to each other, adjacent to each other along the extension axis of said casing.

[0057] Generally, the constituent materials of the movable magnetic element have a first polarity, the constituent materials of the first fixed magnetic element have a second polarity, and the constituent materials of the second fixed magnetic element have a third polarity.

[0058] For example, the first polarity is different from the second polarity to generate an attractive force and the first polarity is identical to the third polarity to generate a resistive force.

[0059] In this embodiment, the control device may comprise two force feedback devices each located at an end of travel.

[0060] . Brief description of the drawings

[0061] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the indexed drawings in which:

[0062] [Fig.l], is a schematic view of a control device comprising a force feedback device according to the prior art;

[0063] [Fig.2A] is a schematic view of a control device comprising a force feedback device according to [Fig.2A], in an initial position;

[0064] [Fig.2B] is a schematic view of a control device comprising a force feedback device according to a first embodiment of the invention, in an end-of-stop position;

[0065] [Fig.3] illustrates the intensity of the force of the force device exerted on the pusher of figure 2 as a function of the translational movement of said lever;

[0066] [Fig.4A], [Fig 4B] are perspective views of a control device comprising a force feedback device according to a second embodiment of the invention, Fig 4B being shown in transparency;

[0067] [Fig.4C] is a detail view of the control device of Figures A and 4B; and

[0068] [Fig.5] illustrates, in radial section, the resistive force exerted on the lever of the control device of Fig 4A as a function of the angular displacement of said lever.

[0069] Detailed description of at least one embodiment

[0070] With reference to the example illustrated in Figures 2 and 2B, a control device 10 comprises a control lever 11 secured to a lever 11a that can rotate about an axis A2. The lever 11 further comprises a stop 11b secured to the lever 11a.

[0071] The control device 10 further comprises two force feedback devices 12 capable of generating a resistive force upon contact with the stop 11b of the lever 11.

[0072] The two force feedback devices 12 are each located at one end of the travel limit of the lever 11a.

[0073] Each of the force feedback devices 12 comprises a casing 13 and a pusher 14 or shaft sliding in said casing 13 along the extension axis of the casing 13 between a stop start zone Z1 and a stop end zone Z2.

[0074] In a non-limiting manner, the casing 13 here has the shape of a conical cylinder.

[0075] Each force feedback device 12 further comprises a movable magnetic element 15 secured to the pusher 14.

[0076] Each force feedback device 12 comprises a first fixed magnetic element 16 and a second fixed magnetic element 17, said first and second fixed magnetic elements 16, 17 are integral with the casing 13 and arranged opposite each end of said casing 13. As illustrated, the movable magnetic element 15 and the fixed magnetic elements 16, 17 are arranged on the extension axis of the casing 13.

[0077] The movable magnetic element 15 is a permanent magnet, or simply magnet in common language, that is to say an object made of a hard magnetic material.

[0078] The fixed magnetic elements 16, 17 are also permanent magnets.

[0079] The polarity of the materials constituting the mobile magnetic element 15 and the fixed magnetic elements 16, 17 is chosen so that the displacement induced by the mobile magnetic element 15 is in a direction of moving away from or towards each of the fixed magnetic elements 16, 17. In general, the materials constituting the mobile magnetic element 15 have a first polarity, the materials constituting the first fixed magnetic element 16 have a second polarity, and the materials constituting the second fixed magnetic element 17 have a third polarity.

[0080] For example, the first polarity is different from the second polarity to generate an attractive force and the first polarity is identical to the third polarity to generate a resistive force.

[0081] As can be seen in [Fig.2A], the lever 11a of the control device 10 is centered and the pusher is in the zone ZI of start of stop. The first movable magnetic element 15 is in abutment against the first fixed magnetic element 16.

[0082] As can be seen in [Fig.2B], the lever 11a of the control device 10 is moved angularly towards one of the two force feedback devices 12 and the pusher is moved towards the end-of-stop zone Z2. The first movable magnetic element 15 is in abutment on the casing, as close as possible to the second fixed magnetic element 17.

[0083] As can be seen in [Fig.3], at 0 mm of travel of the pusher 14, corresponding to [Fig.2A], the first movable magnetic element 15 is in abutment against the first fixed magnetic element 16. The first fixed magnetic element 16 attracts the first movable magnetic element 15.

[0084] At 9 mm of travel of the pusher 14, the first mobile magnetic element 15 is in abutment on the casing, as close as possible to the second fixed magnetic element 17, this is the position visible in [Fig.2B].

[0085] At any time during the travel of the pusher 14 in the casing 13, the second fixed magnetic element 17 pushes the first mobile magnetic element 15 towards the first magnetic element 16, which generates the movement of the first mobile magnetic element 15 in the casing 13, and therefore the translational movement of the pusher 14.

[0086] When the lever 11 pivots around the axis of rotation A2, the stop 11b comes into contact with the pusher 14 of one of the force feedback devices 12, which translates inside the casing 13 and moves the pusher 14 towards the second fixed magnetic element 17 which pushes the first mobile magnetic element 15 towards the first magnetic element 16, generating a resistive force on the lever 11a of the lever 11a.

[0087] The force feedback device 12 here generates a force feedback over the entire travel of the lever 11.

[0088] The force feedback device 12 behaves in the same way as a mechanical spring system with a different return force profile, as seen in [Fig.3].

[0089] The force feedback device 12 forms a magnetic force feedback device avoiding having parts in contact to perform the force feedback, unlike devices using mechanical springs. This makes it possible to reduce the wear and fatigue of the constituent elements of the force feedback device and thus to reduce the variation in performance over time.

[0090] In the example illustrated in Figures 4A, 4B, 4C and 5, a control device 20 here comprises a control stick or joystick 21 which is angularly movable in an angular range here between -90° and 90°. The position at 0° corresponds to the vertical position visible in Figures 4A and 4B.

[0091] The handle 21 here comprises a lever or shaft 24, here, in the extension of said handle 21 and integral in rotation with a control member or rotation axis 24a. Alternatively, it could be provided that the handle 21 is offset from the lever 24.

[0092] The control device 20 further comprises a force feedback device 22 capable of generating a resistive or driving force on the lever 24.

[0093] The force feedback device 22 here generates a force feedback over part of the travel of the lever 24, in particular over the end-of-travel zones of the lever 24 of the control lever.

[0094] The force feedback device 22 comprises a first casing 23 extending along an angular segment and internally delimiting a main angular guide rail 23a, a second casing 22a angularly spaced from a first side of the first casing 23 by a non-zero circumferential distance el, visible in [Fig.4C] and a third casing 22b angularly spaced from a second side of the first casing 23 by a non-zero circumferential distance (not referenced).

[0095] The second and third casings 22a, 22b are arranged opposite each lateral side of the first casing 23.

[0096] The guide rail 23a is here open on its upper part. Alternatively, the main guide rail 23a could be closed on its upper part. In this case, the lever 21 is offset from the lever 24.

[0097] The force feedback device 22 further comprises a movable magnetic element 25 secured to the lever 24.

[0098] The force feedback device 22 comprises a first fixed magnetic element 26 secured to the second casing 22a and a second fixed magnetic element 27 secured to the third casing 22b. Said first and second fixed magnetic elements 26, 27 are arranged opposite each lateral side of the first casing 23.

[0099] The movable magnetic element 25 is a permanent magnet, or simply magnet in common language, that is to say an object made of a hard magnetic material.

[0100] As illustrated in Figures 4A and 4B, the magnet of the movable magnetic element 25 extends over an angular range here between 5° and 15°.

[0101] The main guide rail 23a of the main casing 23 is for example made of magnetic material.

[0102] The first fixed magnetic element 26 comprises two permanent magnets facing each other spaced apart by a first non-zero air gap (not referenced) and forming a first secondary guide rail 26a for the mobile magnetic element 25.

[0103] The second fixed magnetic element 27 comprises two permanent magnets facing each other spaced by a second non-zero air gap (not referenced) and forming a second secondary guide rail 27a for the mobile magnetic element 25.

[0104] In the example illustrated, the first air gap is equal to the second air gap. This makes it possible to obtain a symmetrical force law.

[0105] Alternatively, one could provide that the first air gap is different from the second air gap. The air gap impacts the magnetic force. One can choose to modify it if one wants different levels of haptic feedback for the rider in the two end zones.

[0106] As illustrated, and in a non-limiting manner, the magnets of the first fixed magnetic element 26 extend over an angular range of between 5° and 15°.

[0107] As illustrated, and in no way limiting, the magnets of the second fixed magnetic element 27 extend over an angular range of between 5° and 15°.

[0108] Having two sides equipped with fixed magnetic elements makes it possible to balance the forces exerted on the lever 24 of the control device 20. Indeed, having a single fixed magnetic element on one side would not make it possible to push the lever of the control device to the other end-of-travel zone.

[0109] Indeed, having a single fixed magnetic element on one side would not allow the lever of the control device to be pushed to the other end-of-travel zone.

[0110] Alternatively, a structural inversion could be provided in which the mobile magnetic element 25 comprises two facing magnets spaced apart by a non-zero air gap and the first fixed magnetic element 26 and the second fixed magnetic element 27 each comprise a single permanent magnet intended to cooperate with the air gap between the two magnets of the mobile magnetic element 25. Thus, said air gap forms a rail for receiving the fixed magnetic elements 26, 27.

[0111] However, although such an inversion is possible, it may increase the inertia of the moving part, i.e., of the handle 21.

[0112] Generally, the polarity of the materials constituting the main guide rail 23a, the movable magnetic element 25 and the fixed magnetic elements 26, 27 is chosen so that the displacement induced by the movable magnetic element 25 is in a direction of attraction or repulsion.

[0113] Thus, the materials constituting the movable magnetic element 25 have a first polarity, the materials constituting the main guide rail 23a have a second polarity, the materials constituting the first fixed magnetic elements 26 have a third polarity and the materials constituting the second fixed magnetic elements 27 have a fourth polarity.

[0114] For example, the first polarity is different from the second polarity to generate an attractive force and the first polarity is identical to the third polarity and the fourth polarity to generate a resistive force.

[0115] As can be seen in [Fig.5], the torque C exerted on the axis of rotation 24a of the lever 24 depends on the angular position of said lever 24.

[0116] Thus, at a zero angular position, the resistive torque is zero.

[0117] As soon as the lever 24, and therefore the mobile magnetic element 25, approaches one of the fixed magnetic elements 26, 27, on one side or the other, the resistive torque increases abruptly.

[0118] As illustrated in [Fig.4C], each magnet of the fixed magnetic elements 26, 27 is surrounded by a magnetic overthickness spaced circumferentially from the main guide rail 23a by a non-zero distance el. This makes it possible to pass from a zero torque to a resistive torque as abruptly as possible.

[0119] This allows the pilot to clearly identify when the lever 24 changes from one angular range to another.

[0120] Such a solution is particularly advantageous because there is no contact between the lever and the guide rail. Indeed, the role of the guide rail is to channel the field of the moving magnet in order to have more stable performance. There is therefore an air gap between the moving magnet and the rail. When the first moving magnetic element 25 is moved in one of the secondary guide rails 26a, 27a by the user, the repulsive force of the force feedback device 22 generates the movement of the first moving magnetic element 25 towards the main guide rail 23a, and therefore the angular movement of the lever 24.

[0121] The force feedback device 12, 22 forms a magnetic force feedback device avoiding having parts in contact to carry out the force feedback, unlike devices using mechanical springs.

[0122] The force feedback device 12, 22 is integrated over at least part of the travel of the lever 11a, 24 so as to create an attractive or repulsive force.

[0123] The control device 10, 20 thus comprises a mechanical path configured to prevent the movement of the lever 11a, 24 and therefore of the control lever 11, 21, either in translation or angularly depending on the embodiment, from being completely free.

[0124] The control lever may be, for example, a throttle lever, allowing in particular the activation of a thrust reversal, the activation of a post-combustion system and, in general, any control lever requiring force feedback.

[0125] However, provision could be made to maintain the mechanical springs in the event of failure of the magnetic force feedback device.

[0126] Thanks to the force feedback device integrated into the control device, the driving sensations are restored, which increases safety.

[0127] The force feedback device makes it possible to limit accidental movements of the lever and its displacement under load.

[0128] When using the force feedback device in a throttle, this prevents the throttle from remaining in a given position for too long to limit the risk of forgetting.

[0129] Furthermore, such a force feedback device makes it possible to improve the stability of the force law over time by the absence of contact at the level of the force zones.

Claims

Claims

1. Control device (10, 20), in particular for an aircraft, comprising at least one control lever (11, 21) secured to a control lever (11a, 24) movable along a displacement path and at least one force feedback device (12, 22) capable of generating a resistive or driving force on said control lever (11a, 24) over at least part of the displacement path, the force feedback device (12, 22) comprising at least one main casing (13, 23), characterized in that the force feedback device (12, 22) comprises: - a movable magnetic element (15, 25) movable in the main casing (13, 23); and - at least one first fixed magnetic element (16, 17; 26, 27) located at one end of the travel of the control lever (11a, 24) and intended to cooperate with the movable magnetic element (15, 25) in an end-of-travel zone of the control lever (11a, 24).

2. Control device (10, 20) according to claim 1, wherein the movable magnetic element (15, 25) and / or the fixed magnetic element (16, 17; 26, 27) comprises at least one permanent magnet.

3. Control device (10, 20) according to any one of the preceding claims, wherein the force feedback device (12, 22) is configured to generate force feedback over at least a portion of the movement stroke of the control lever (11a, 24).

4. Control device (10, 20) according to any one of the preceding claims, in which the control lever (11a, 24) is rotatable about an axis of rotation (A2, 24a) according to an angular displacement travel between two end-of-travel zones.

5. Control device (20) according to any one of the preceding claims, in which the movable magnetic element (25) is integral with the control lever (24) and in which the casing (23) extends along an angular segment and internally delimits a main angular guide rail (23a) in which the control lever control (24) is angularly movable within an angular range extending between two end-of-travel zones.

6. Control device (20) according to claim 5, in which the force feedback device (22) comprises a second casing (22a) angularly spaced from a first side of the main casing (23) by a non-zero circumferential distance (el) and comprising the first fixed magnetic element (26) and in which the first fixed magnetic element (26) comprises two permanent magnets facing each other spaced by a first non-zero air gap and forming a first secondary guide rail (26a) for the mobile magnetic element (25).

7. Control device (10) according to any one of claims 1 to 4, in which the control lever (11a) comprises a stop (11b) and in which the force feedback device (12) comprises a pusher (14) movable in translation in the casing (13) along an extension axis of said casing (13) and intended to be in contact with the stop (11b) of the control lever (11) in an end-of-travel position.

8. Control device (10) according to claim 7, in which the force feedback device (12) comprises a second fixed magnetic element (17) integral with the casing (13), said first and second fixed magnetic elements (16, 17, 26, 27) being arranged opposite each other at each end of said casing (13), the fixed magnetic elements (16, 17) and the mobile magnetic element (15) cooperating by being placed close to each other, adjacently along the axis of extension of said casing (13).

9. A control device (10) according to claim 8, wherein the constituent materials of the movable magnetic element (15) have a first polarity, the constituent materials of the first fixed magnetic element (16) have a second polarity, and the constituent materials of the second fixed magnetic element (17) have a third polarity.

10. A control device (10) according to claim 9, wherein the first polarity is different from the second polarity to generate an attractive force and the first polarity is identical to the third polarity to generate a resistive force.

Images