A vehicle comprising a suspension and an electromechanical rotating device for controlling the suspension, and a method for controlling the movement of the suspension of the vehicle

Abstract

A vehicle including a suspension and an electromechanical rotary device for controlling the suspension, and a method for controlling the motion of a vehicle suspension. The vehicle has a vehicle body (9), at least one hub (10) of a wheel (11), and a suspension (12) connecting the hub (10) to the vehicle body (9). The suspension has a suspension arm (14) hingedly connected to the vehicle body (9) and the hub (10), elastic means (16), and an electromechanical rotary actuator (18) operable with leverage (24) to actively regulate and damp the motion of the suspension (12).

Description

Technical Field

[0001] The present invention generally relates to the field of motor vehicles. In particular, the present invention relates to a vehicle comprising a suspension and an electromechanical rotary device for controlling this suspension, and to a method for adjusting the movement of a vehicle suspension.

Background Art

[0002] Solutions are known in which a vehicle suspension is associated with an electromechanical rotary device for the active control and / or damping of its movement.

[0003] An example of a similar solution is known from US10166833 B2, which describes an electromechanical device that actuates a torsion bar connected in sequence to a wheel hub or one of the suspension arms via a three-point support mechanism.

[0004] The main drawback of this device is that the presence of a low-rigidity (and thus highly elastically deformable) element, such as a torsion bar arranged in series in the torque transmission chain, acts as a low-pass filter and considerably reduces the passband of the system, so that it cannot be used to actuate the movement of the wheel at high frequencies (F>5 Hz), nor to damp the movement of the suspension.

[0005] For these reasons, this device can only be used to control the movement of the vehicle at low frequencies, i.e., the movement of the vehicle body itself (rolling, pitching, shaking). Furthermore, in order to sufficiently damp the movement of the vehicle suspension, this device must be arranged in parallel with a conventional shock absorber.

[0006] A second example of the prior art is represented by the hydraulic rotary actuator of patent DE10043711, in which two different architectures are described. In the first architecture, the hydraulic rotary actuator is attached to the vehicle body and interacts with one of the suspension arms via a system consisting of a lever and a rod. In the second architecture, the hydraulic rotary actuator is directly supported on one of the suspension arms via an elastic suspension consisting of a multi-joint parallelogram or pantograph and a spring, and the actuator vibrates perpendicular to the suspension arm, thereby forming a vibrating mass and being able to attenuate the vibration of the wheel. The torque transmission between the hydraulic rotary actuator and the vehicle body is realized by a three-point motion mechanism consisting of a lever and a rod.

[0007] Both architectures are, in principle, capable of actively controlling the rolling and pitching movements of the vehicle and damping the vertical vibrations of the wheels. Also, in this example, therefore, it only relates to the active control of the low-frequency movements (roll and pitch) of the vehicle body. On the other hand, regarding the high-frequency movements of the suspension, only the possibility that the high-frequency movements can be damped is described.

[0008] Furthermore, in the second architecture, the damping of the wheel vibrations is mainly achieved by utilizing the dynamic effect of a vibrating mass consisting of a hydraulic rotary actuator elastically suspended with respect to the suspension arm. However, in the first architecture, no details are provided on how the hydraulic rotary actuator can be used and controlled to damp the said vibrations. Thus, the explanation on this point is completely ambiguous and only theoretically valid. In particular, no details are provided regarding the structural features of the hydraulic rotary actuator. For example, it is not specifically described anywhere whether this actuator consists of a hydraulic actuator directly driven by an electric motor controlled by appropriate electronics, or whether it consists of a hydraulic rotary jack connected to a hydraulic accumulator element via an appropriate control solenoid valve. Furthermore, no details are provided regarding the principles and logic at the vehicle dynamics level for controlling the hydraulic rotary motor.

[0009] Examples of actuators configured to actively impart motion to the suspension are also known from WO2018 / 172762. However, this solution does not take into account the possibility that the actuator operates in damping, since all steps in which the suspension is stressed (i.e., when the wheel encounters a raised obstacle or an incline) provide for active intervention of the actuator.

[0010] Therefore, based on the examples available in the prior art, it is impossible to configure a suspension such that high-frequency motions can be alternately and actively induced and damped. SUMMARY OF THE INVENTION

[0011] The object of this invention is to overcome the aforementioned problems.

[0012] To obtain this result, a vehicle is provided with a suspension associated with an electromechanical rotary device capable of controlling the movement at a high frequency (F>5 Hz) typical of the vertical movement of the wheels. This causes the high-frequency movement of the suspension while attenuating the high-frequency movement of the suspension caused by external factors (such as road unevenness, braking, acceleration, cornering, etc.), electrically braking the movement of the suspension, and in some cases converting the kinetic energy from the movement of the suspension into electrical energy (regenerative damping).

[0013] According to an embodiment of the present invention, the electromechanical rotary device comprises an electromechanical device (conveniently, a conventional electric motor, known per se to those skilled in the art in the context of similar applications) coupled to a speed reducer, the output of which is rigidly connected, via a kinematic mechanism of a known type, to one of the suspension elements that moves with the wheel hub. This element may be one of the suspension arms, the wheel hub itself, or a structural part supporting the spring plate of the suspension. The output of the speed reducer is connected, without the intervention of elastic parts that undergo large deformations, such as torsion bars, elastic parts that deform by bending, elastic parts that deform by traction and compression, etc., to one of the suspension elements that moves rigidly with the wheel hub. In fact, only in this way can the passband of the device be kept above the high frequency (F>5 Hz) typical of the up and down movement of the wheels, and thus the movement of the suspension in the frequency range of the lever can be caused and attenuated at the same time.

[0014] In the case of a front double wishbone suspension, a particularly advantageous kinematic mechanism is one in which the rotary device has a housing connected to the vehicle body near the chassis attachment point of the lower arm of the suspension, and a lever that is part of the kinematic mechanism and integral with the speed reducer has a rotational axis parallel to the rotational axis of the hinge that connects the lower arm of the suspension to the chassis, and is hingedly connected to a rod that is hingedly connected to a structural element that supports the suspension spring plate. This structural element may be a conventional shock absorber, and thus, by acting in parallel with the electromechanical rotary device, performs a damping action on the suspension movement, or this element does not perform a damping action and thus constitutes only a cylindrical pair for supporting the spring plate of the suspension. In this case, only the damping action of the suspension movement is performed by the electromechanical rotary device. This embodiment is particularly advantageous because the electromechanical rotary device can be installed without disrupting the classical architecture of the double wishbone suspension.

[0015] The housing of the electromechanical rotary device may be rigidly connected to the vehicle body, for example, by screws, or may be connected to the vehicle body via a suspension on elastic and damping means (such as support blocks or wedges) of a known embodiment in order to reduce the transmission of vibrations to the vehicle body. The stiffness and damping values of these elastic and damping means are ideally assigned so as not to introduce dynamics into the frequency band of interest shown in the frequency range from 0 Hz to 50 Hz in the case of an automotive suspension. In practice, the elastic body must have a sufficiently high stiffness, and the damping element may or may not be explicitly required depending on the performance required from the perspective of vibration filtering.

[0016] The speed reducer is preferably in the form of a multi-stage planetary gear train in which the input of each stage is the sun gear, the output of each stage is the planetary carrier, and the ring gear is fixed to and integrated with the housing of the device.

[0017] The electromechanical device may have its position and torque controlled by an electronic control unit (inverter). This electronic control unit, which is known per se, is based on sensors connected thereto that are capable of measuring the magnitudes of the vertical movements of the wheel hub and the vehicle body, and aims to reduce the swaying, rolling, and pitching movements of the vehicle body while reducing the vertical vibrations of the wheels, and controls the electromechanical device according to a known strategy for controlling the dynamics of the vehicle. As an example of an application, these sensors may be composed of two accelerometers that are arranged integrally with the lower arm of the suspension and are respectively arranged at the connection points with the spring body (dome) of the suspension and are capable of measuring the vertical acceleration at the points where they are connected. It is also conceivable to use an accelerometer integrated with a point on the vehicle body and a running sensor of the suspension.

[0018] The electronic control unit is electrically connected to an electrical energy storage element (battery). Electrical energy is taken out from there to supply power to the electromechanical device during the step (active operation) in which the electromechanical device causes the movement of the suspension, or the electrical energy regenerated by the electromechanical device during the step (damping step, preferably regeneration) in which the electromechanical device brakes the movement of the suspension is led there.

[0019] The electronic control unit is a component external to the electromechanical rotary device and may thus be arranged inside the vehicle at a considerable distance from the device, or may form an extension in the axial direction of the electromechanical device and be completely integrated within the electromechanical device. In the latter case, a so-called "smart actuator" type architecture, which is well known to those skilled in the art, will basically be implemented, where all the components necessary for the operation of the suspension, except for the electrical wiring for connection to the rest of the vehicle (for example, for supplying power to the electrical and electronic devices incorporated in the suspension), are basically integrated within the suspension.

[0020] Furthermore, conventionally, an angular position sensor incorporated in an electromechanical device for torque and speed control of the electromechanical device can be used as a suspension travel sensor within a known vehicle dynamics control strategy. This is possible because the motion transmission mechanism from the wheel hub of the electromechanical rotary device to the electromechanical device is a rigid body, and there is an inherent kinematic link between the relative position of the wheel hub with respect to the vehicle body and the rotation of the electromechanical device. Thus, in the prior art, it is possible to eliminate the known position / acceleration sensors used to measure the relative motion of the wheel hub with respect to the vehicle body while reducing the complexity of the resulting leverage struts and installations.

[0021] The foregoing and other objects and advantages are achieved, according to one aspect of the invention, by a vehicle and a method having the features defined in the appended claims. Preferred embodiments of the invention are defined in the dependent claims.

[0022] Next, the functional and structural features of some preferred embodiments of the vehicle and method according to the invention will be described. Referring to the accompanying drawings, it is as follows.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

[0024] Before explaining in detail a plurality of embodiments of the present invention, it should be made clear that the present invention is not limited to the details of the structure and configuration of the components shown in the following description or in the drawings. The present invention can assume other embodiments and can be implemented or configured in different ways in practice. Also, it should be understood that the wording and terms are for illustrative purposes and should not be construed in a limiting manner.

[0025] Referring to the figures as an example, the vehicle has a vehicle body 9, at least one hub 10 adapted to support a wheel 11 such that the wheel 11 is rotatable around the hub 10, and a suspension 12 connecting the hub 10 to the vehicle body 9 such that the hub 10 is vertically vibratable with respect to the vehicle body 9.

[0026] The suspension 12 is composed of a suspension arm 14 (conveniently, a conventional lower swing arm) hinge-coupled on one side to the vehicle body 9 and on the other side to the hub 10, and elastic means 16 suitable for biasing the suspension arm 14 towards a predetermined neutral position of static equilibrium with respect to the vehicle body 9 (i.e., the position taken by the suspension arm in a state where it is substantially on a flat ground under the action of the gravitational force acting on the vehicle body 9).

[0027] There is also an electromechanical rotary actuator 18 having an electromechanical machine 20 integrally connected to the vehicle body 9 and coupled to a speed reducer 22. The speed reducer 22 has at least one reduction stage 23a, 23b coupled to an output shaft 23c having a rotation axis parallel to the hinge axis of the suspension arm 14 on the vehicle body 9.

[0028] The suspension 12 further comprises a leverage 24 adapted to transmit motion from at least one reduction stage 23a, 23b to the suspension arm 14 by the output shaft 23c of the reduction stage 23a, 23b. The leverage 24 and the output shaft 23c of the reduction stage 23a, 23b have components configured as (or formed by) substantially rigid bodies (i.e., rigid body torsion, bending, traction, and compression components) without impairing the possibility that the components can be connected to each other. This is different from what occurs in the prior art where a torsion bar or other elements are used and are configured to transmit motion from the speed reducer to the suspension arm particularly by their torsional, bending, traction, or compressive elastic deformation.

[0029] Also provided are sensor means 26 adapted to detect parameters indicating the motion of the suspension arm 14, an electronic control unit 28 adapted to control the electromechanical machine 20 of the electromechanical rotary actuator 18 in terms of torque and angular position based on the signal transmitted from the sensor means 26, and a battery 30 adapted to alternately supply power to and receive current from the electromechanical rotary actuator 18.

[0030] The electromechanical rotary actuator 18 is operable between an active adjustment state and a damping state. In the active adjustment state, the electromechanical rotary actuator 18 is powered by the battery 30 and is configured to transmit a force to the suspension arm 14 through the lever 24 to cause relative movement of the suspension arm 14 with respect to the vehicle body 9. In the damping state, the electromechanical rotary actuator 18 uses the battery 30 as a power source, transmits a force to the suspension arm 14 through the lever 24 to counteract the relative movement of the suspension arm 14 with respect to the vehicle body 9, and causes negative work to be done on the suspension 12.

[0031] The electromechanical rotary actuator 18 is operated between the active adjustment state and the damping state according to a command from the electronic control unit 28, and gives movement to the suspension arm 14 at a maximum frequency higher than 5 Hz, or damps the movement of the suspension arm 14 (for example, wheel movement having a frequency on the order of 10 to 15 Hz) at a maximum frequency higher than 5 Hz. This can be advantageously obtained through sensor means 26 that detects the vertical movement of the suspension arm 14 and transmits it to the electronic control unit 28 according to a method within the reach of those skilled in the art, so that the electronic control unit controls the electromechanics 20 of the electromechanical rotary actuator 18 for torque and angular position, gives the suspension arm 14 movement having a maximum frequency higher than 5 Hz, or damps the movement of the suspension arm 14 having a maximum frequency higher than 5 Hz.

[0032] According to a preferred embodiment, the rotation axes of the output shafts 23c of the reduction stages 23a, 23b are parallel to, but do not coincide with, the hinge axis of the suspension arm 14 with respect to the vehicle body 9.

[0033] The suspension 12 has at least two telescopically extendable and retractable portions (as illustrated in FIG. 1 showing an embodiment of a double wishbone type front suspension), one of the portions having one end connected to the suspension arm 14 by a joint, and the other of the portions having one end connected to the vehicle body 9 by a joint, and may further include a cylindrical pair 17.

[0034] Alternatively (as illustrated in FIG. 2 showing an embodiment of a wishbone type rear suspension), there may be no cylindrical pair.

[0035] According to an embodiment, the cylindrical pair 17 is configured to substantially avoid exerting a damping effect on the movement of the suspension. In this case, the cylindrical pair 17 is substantially configured not to resist the movement of the suspension 12 (for example, it may consist of two cylindrical portions that are telescopically extendable and retractable with minimal friction, even if there is no damping fluid in these cylindrical portions).

[0036] Alternatively, the cylindrical pair 17 may be configured to exert a damping effect on the movement of the suspension 12 in addition to the damping effect caused by the electromechanical rotary actuator 18.

[0037] In this case, the cylindrical pair 17 may be configured, for example, as a conventional automotive shock absorber.

[0038] According to an embodiment, the elastic means 16 has one end connected to a portion that can be attached to the vehicle body 9 of the cylindrical pair 17, and the other end connected to a portion that is attached to the suspension arm 14 of the cylindrical pair 17, and the lever 24 is connected to the portion (for example, a spring plate that is integral with or near the portion of the cylindrical pair 17 on which one end of the spring 16 rests and is attached to the suspension arm 14) attached to the suspension arm 14 of the cylindrical pair 17.

[0039] Preferably, the leverage 24 has a lever 24a integrally formed with the output shaft 23c of at least one reduction gear stage 23a, 23b in the torsional direction, and a rod 24b that is articulated to the lever 24a and whose other end is hinged to a portion of the cylinder pair 17 attached to the suspension 14, or the hub 10, or the suspension arm 14. The lever 24a and the rod 24b are configured as rigid bodies basically to provide a rigid motion mechanism for transmitting motion between the reduction gear stages 23a, 23b and the suspension arm 14.

[0040] According to an embodiment, the speed reducer 22 consists of a multi-stage planetary gear train, and the speed reducer 22 is housed in the housing of an electromechanical rotary actuator 18 integrally connected to the vehicle body 9.

[0041] Each stage 23a, 23b of the planetary gear train has a sun gear that meshes with the planet of the planetary carrier. The planetary carrier meshes with a radially outer ring. The planetary gear train is configured such that the input of each stage is the sun gear, the output of each stage is the planetary carrier, and the outer ring is fixed to the housing of the electromechanical rotary actuator 18. integrally so as not to rotate to is fixed.

[0042] Advantageously, the speed reducer 22 has a two-stage planetary gear train, the planetary carrier of the first stage is rigidly connected to the lever 24a of the leverage 24 in the torsional direction, and the sun gear of the second stage is rigidly connected to the shaft of the electromechanical device 20 in the torsional direction.

[0043] According to an embodiment (illustrated in FIG. 6A), the electromechanical rotary actuator 18 is rigidly connected to the vehicle body 9, for example, by a spring or the like.

[0044] Alternatively (illustrated in Figure 6B), the electromechanical rotary actuator 18 may be connected to the vehicle body 9 via elastic and damping means 3, which are known per se, in order to reduce the transmission of vibrations towards the vehicle body 9. The stiffness and damping values of these elastic and damping means 32 are ideally assigned in such a way as not to introduce the dynamics of the frequency band of interest, which, in the case of an automotive suspension, is the frequency range from 0 Hz to 50 Hz. In practice, the elastic means must have a sufficiently high stiffness, while the damping element can be determined as explicitly required or not, depending on the performance required from the point of view of vibration filtering.

[0045] Advantageously, the electronic control unit 28 is fully integrated within the electromechanical device and forms an extension in the axial direction of the electromechanical 20.

[0046] According to one aspect of the invention, there is provided a method for adjusting the movement of a vehicle suspension, comprising the steps of providing a vehicle according to any of the above-described embodiments, and detecting, by sensor means 26, the relative position and speed between the vehicle body 9 and the hub 10.

[0047] When a reciprocating movement between the vehicle body 9 and the hub 10 is detected, the method according to the invention further comprises the following steps of controlling the electromechanical rotary actuator 18 by the electronic control unit 28.

[0048] - When the movement of the hub 10 is such that the absolute distance between the hub and the vehicle body 9 tends to decrease with respect to the absolute distance that the hub 10 has from the vehicle body 9 in the neutral state of the static force balance of the suspension 12 (that is, when the wheel faces an uphill slope and the hub 10 rotates clockwise as viewed from the perspective of FIG. 1 and rises above the neutral position), supply current from the battery 30 to the electromechanical rotary actuator 18 to generate torque, and transmit the torque to the suspension arm 14 by the lever 24 to cause an effect on the suspension arm 14 at a maximum frequency F>5 Hz. As long as the relative speed between the hub 10 and the vehicle body 9 does not change sign, further decrease the absolute distance between the hub 10 and the vehicle body 9 (that is, promote further upward swing of the hub), interrupt the power supply from the battery 30 to the electromechanical rotary actuator 18, cause the electromechanical rotary actuator 18 to function as a generator, and transmit the generated current to the battery 30.

[0049] - When the movement of the hub 10 is such that the absolute distance between the hub and the vehicle body 9 tends to increase with respect to the absolute distance that the hub 10 has from the vehicle body 9 in the neutral state of the static force balance of the suspension 12 (that is, when the wheel faces a downhill slope and the hub 10 descends below the neutral position and rotates counterclockwise as viewed from the perspectives of FIGS. 1 and 2 and descends below the neutral position), supply current from the battery 30 to the electromechanical rotary actuator 18 to generate torque, and transmit the torque to the suspension arm 14 by the lever 24 to cause an effect on the suspension arm 14 at a maximum frequency F>5 Hz. As long as the relative speed between the hub 10 and the vehicle body 9 does not change sign, further increase the absolute distance between the hub 10 and the vehicle body 9, interrupt the power supply from the battery 30 to the electromechanical rotary actuator 18, cause the electromechanical rotary actuator 18 to function as a generator, and transmit the generated current to the battery 30.

[0050] To better understand the control strategy described above, two examples of suspending movement adjustment will be described below with reference to FIGS. 7 and 8 (the first example), and FIGS. 9 and 10 (the second example).

[0051] Consider a simplified model of the vehicle suspension (illustrated in FIGS. 7 and 9). Therein, the vehicle body 9 and each wheel 11 of the vehicle are schematically shown as two masses, an upper and a lower mass, respectively, which are mechanically connected in parallel to each other via a spring 16 and an electromechanical rotary actuator 18.

[0052] Consider a specific scenario where the wheel collides with an obstacle on the road, such as an artificial bump (ridge). The purpose of this control strategy (which is known per se) is to control the rotary actuator 18 in terms of torque and position so as to keep the vehicle body 9 at a constant vertical height at all times, thereby compensating for the inevitable change in the force of the spring 16 due to the vertical displacement of the wheel 11 relative to the vehicle body 9 when crossing the obstacle.

[0053] Fs represents the force exerted by the spring on the vehicle body (previously considered positive if upward) and the force exerted on the wheel (previously considered positive if downward) according to the principle of action and reaction. V represents the relative vertical speed between the vehicle body and the wheel, with the extension side being positive conventionally. F represents the force exerted by the rotary actuator on the vehicle body, with the downward direction being positive conventionally. According to the principle of action and reaction, the rotary actuator exerts the same magnitude of force F on the wheel, which was previously considered positive in the upward direction.

[0054] Consider the force F - velocity V diagram of FIG. 8 (in which the velocity V and force F of the actuator are shown) in accordance with such a code rule. The first and third quadrants (indicated by Roman numerals I and III) are, by convention, the typical operating quadrants of a shock absorber. A conventional shock absorber dissipates the kinetic energy of the suspension, while the electromechanical rotary actuator of the present invention attenuates the movement of the suspension and preferably regenerates the kinetic energy of the suspension into electrical energy, thereby providing regenerative damping and a flow of electrical energy from the actuator to the battery. The second and fourth quadrants (indicated by Roman numerals II and IV) correspond to the active operation of the suspension during compression and extension, respectively, and are thus the operating quadrants not conventionally allowed for a shock absorber. In these two quadrants, the electromechanical rotary actuator of the present invention causes the movement of the suspension that results in the absorption of electrical energy from the battery, thus causing a flow of electrical energy from the battery to the actuator.

[0055] The main phenomena occurring during obstacle crossing are summarized as follows. In Step 1 (the first configuration from the left in Figure 7), the vehicle moves on a smooth road. The suspension spring supports the vertical load due to the vehicle body weight. The suspension does not move vertically (V = 0), and the force F of the rotary actuator is zero. On the force-velocity plane of Figure 8, this state corresponds to the origin. In Step 2, when the wheel rides over an obstacle, the control attempts to maintain the vehicle body at the same vertical height as in Step 1. As the wheel rides over the obstacle and approaches the vehicle body, the suspension is in a compressed state (V < 0). The spring is more compressed than in Step 1, and an upward direct elastic force Fs acts on the vehicle body. To compensate for this force Fs, the rotary actuator needs to act on the vehicle body with an equal and opposite downward force F. According to the principle of action and reaction, the rotary actuator acts on the wheel with an equal and opposite upward force F. The actuator operates in the second quadrant of the force-velocity graph of Figure 8, which corresponds to the active operation during compression. In reality, in this step, the actuator does not actively "help" the wheel follow the bump, pull the wheel towards the vehicle body side, or give a moving effect to the vehicle body. While operating in this way, since the force F exerted by the actuator on the wheel and the vertical velocity of the wheel are always in the same direction, the actuator does positive work on the suspension (the vertical velocity of the vehicle body is theoretically zero, and thus the work done by the force F exerted by the actuator on the vehicle body is also theoretically zero). Note that in such a situation of the relative velocity V of the vehicle body and the negative wheel (compression), the shock absorber acts on the vehicle body with an upward force against the relative compression movement of the vehicle body and the wheel, facilitating the upward movement of the vehicle body, and thus operates in the third quadrant of the force-velocity graph.

[0056] In step 3, when the wheel reaches the apex of the obstacle, the control strategy aims to maintain the vehicle body at the same vertical height as in steps 1 and 2. Since the wheel is at the apex of the obstacle, the relative speed of the suspension is zero (V = 0), but the spring is compressed more than in step 2, increasing the value of the elastic force Fs acting on the vehicle body upward. To compensate for this increased force Fs, it is necessary to increase the value of the downward force F applied by the rotary actuator to the vehicle body. According to the principle of action and reaction, the rotary actuator applies an equal and opposite force F to the wheel, resulting in an upward direction. By applying a positive force F, the actuator operates at zero speed and moves between the first and second quadrants on the vertical axis of the force - speed graph in Fig. 8, which corresponds to the active operation at zero speed. In reality, in this step, the actuator continues to actively maintain the wheel at the apex of the bump without affecting the vertical displacement of the vehicle body. Thus, in the situation where the relative speed V between the vehicle body and the wheel is zero, the shock absorber reacts with a zero force F and acts at the origin of the force - speed graph.

[0057] Finally, in step 4 where the wheel descends from the obstacle, the control strategy controls to keep the vehicle body at the same vertical height as in steps 1 - 3 again. When the wheel descends from the obstacle and separates from the vehicle body, the suspension is in an extended state (V>0), and the spring is always compressed, applying an upward elastic force Fs to the vehicle body. To compensate for this force Fs, the rotary actuator needs to apply an equal and opposite downward force F to the vehicle body. According to the principle of action and reaction, the rotary actuator applies an equal and opposite upward force F to the wheel. And the actuator extends by applying the force F that resists the extension to the main body and the wheel, whereby the actuator functions as a shock absorber in the first quadrant of the force - velocity graph of FIG. 8, which corresponds to the damping operation during extension. At this time, since the force F exerted by the actuator on the wheel and the vertical velocity of the wheel are always in opposite directions during this step, the actuator does negative work on the suspension (the vertical velocity of the vehicle body is theoretically zero, and thus the work done by the force F exerted by the actuator on the vehicle body is also theoretically zero). During this operation, the actuator regenerates the kinetic energy of the suspension into electrical energy, and the electrical energy flows from the actuator to the battery.

[0058] Finally, as a second specific scenario, consider the case where the wheel enters a dip (depression) in the road surface. Also in this case, the purpose of the control strategy (already known per se) is to control the rotary actuator 18 in terms of torque and position so as to always keep the vehicle body of the vehicle 9 at the same vertical height, thereby compensating for the inevitable change in the force of the spring 16 due to the vertical displacement of the wheel 11 with respect to the vehicle body of the vehicle 9 when crossing the dip.

[0059] Consider the same convention regarding the signs of force and velocity as already exemplified for the case of the artificial bump. Further, consider the known force F - velocity V diagram of FIG. 10. This diagram is exactly the same as the diagram of FIG. 8, and the same considerations regarding the quadrants already illustrated for FIG. 8 apply.

[0060] Summarizing the main phenomena that occur when crossing a dip, it is as follows. In Step 1 (the first configuration from the left in Fig. 9), the vehicle moves on a smooth road. The suspension spring supports the vertical load due to the weight of the vehicle body. The suspension does not move in the vertical direction (V = 0), and the rotary actuator exerts a force F of zero. In Step 2 when the wheel enters the dip, it is controlled to keep the vehicle body at the same vertical height as in Step 1. When the wheel descends in the dip and moves away from the vehicle body, since the suspension is in an extended state (V > 0), the spring extends more than in Step 1, and thus exerts an additional downward elastic force Fs on the vehicle body. To compensate for this force Fs, the rotary actuator must exert an upward force F equal to the vehicle body on the vehicle body. According to the principle of action and reaction, the rotary actuator exerts an equal and opposite downward force F on the wheel. The actuator operates in the fourth quadrant of the force - velocity graph in Fig. 10, which corresponds to the active operation during extension. In reality, in this step, the actuator actively "helps" the wheel to follow the profile of the slope, pushes the wheel in the opposite direction to the vehicle body, and pushes the wheel without having a moving effect on the vehicle body. In this step, since the force F exerted by the actuator on the wheel and the vertical velocity of the wheel are always in the same direction, the actuator does positive work on the suspension (the vertical velocity of the vehicle body is theoretically zero, and thus the work done by the force F exerted by the actuator on the vehicle body is also theoretically zero). Note that in such a situation of the positive relative velocity V (extension) between the vehicle body and the wheel, the shock absorber resists the relative movement of the extension between the vehicle body and the wheel, exerts a downward force on the vehicle body, thereby facilitating the movement of the vehicle body to the bottom, and operates in the first quadrant of the force - velocity graph.

[0061] In step 3, the wheel has reached the lowest point of the dip, and the control strategy aims to maintain the vehicle body at the same vertical height as in steps 1 and 2. Since the wheel is at the lowest point of the dip, the relative speed of the suspension is zero (V = 0), but the spring extends more than in step 2, increasing the value of the elastic force Fs acting downward on the vehicle body. To compensate for this increased force Fs, the rotary actuator needs to increase the value of the upward force F acting on the vehicle body. According to the principle of action and reaction, the rotary actuator applies an equal and opposite downward force F to the wheel. The actuator operates at zero speed by applying a negative force F. Therefore, it operates between the third and fourth quadrants on the vertical axis of the force - speed graph in Figure 10, which corresponds to an active operation at zero speed. In practice, in this step, the actuator actively continues to hold the wheel at the lowest point of the dip without being affected by the vertical movement of the vehicle body. In a situation where the relative speed V between the vehicle body and the wheel is zero like this, the shock absorber reacts with a force F of zero and thus operates at the origin of the force - speed graph.

[0062] Finally, in step 4 where the wheel rises from the dip and escapes, control is performed with the aim of keeping the vehicle body at the same vertical height as in steps 1 to 3 again. While the wheel exits the dip and approaches the vehicle body, the suspension is in a compressed state (V < 0), and since the spring is always extended, it exerts a downward elastic force Fs on the vehicle body. To compensate for this force Fs, the rotary actuator must exert an equal and opposite upward force F on the vehicle body. According to the principle of action and reaction, the rotary actuator exerts an equal and opposite downward force F on the wheel. And since the actuator performs a compression operation by exerting the force F against the compression on the main body and the wheel, in the third quadrant of the force-velocity graph in FIG. 10, it functions as a shock absorber corresponding to the damping operation during compression. At this time, since the force F exerted by the actuator on the wheel and the vertical velocity of the wheel are always in opposite directions during this step, the actuator performs negative work on the suspension (the vertical velocity of the vehicle body is theoretically zero, and thus the work done by the force F exerted by the actuator on the vehicle body is also theoretically zero). And during this operation, the actuator regenerates the kinetic energy of the suspension into electrical energy, and the electrical energy flows from the actuator towards the battery.

[0063] Based on the above description, it is understood how the rotary actuator transitions from the active operation to the damping operation (regeneration conveniently) based on the above vehicle dynamics control strategy.

[0064] In particular, both when the wheel encounters a bump (starting from the neutral state of the balance of the static suspension force) and when the wheel encounters a dip, the actuator is powered from the battery in the first step to perform active adjustment of the suspension movement until it reaches the top of the bump or the deepest point of the dip, and then in the second step, the power supply from the battery is interrupted, enabling the actuator to function as a generator and thus function as a damper for the suspension.

[0065] According to an embodiment, the step of detecting the relative position and speed between the vehicle body 9 and the hub 10 is carried out by an angular position sensor incorporated in the electromechanics 20 and adapted to enable control in terms of torque and speed.

[0066] Various aspects and embodiments of the vehicle and method according to the present invention have been described. It is understood that each embodiment may be combined with any other embodiment. Furthermore, the present invention is not limited to the described embodiments and can be varied within the scope defined by the appended claims.

Claims

Claim 1 A vehicle comprising a vehicle body (9), a hub (10) adapted to support a wheel (11), whereby the wheel (11) is rotatable about the hub (10), a suspension (12) connecting the hub (10) to the vehicle body (9) and enabling the hub (10) to pivot vertically relative to the vehicle body (9), wherein the suspension (12) comprises a suspension arm (14) hinged to the vehicle body (9) and the hub (10) and fixed by the suspension (12), elastic means (16) adapted to bias the suspension arm (14) towards a predetermined neutral position where static forces on the vehicle body (9) are balanced, an electromechanical rotary actuator (18) including an electromechanical machine (20) integrally connected to the vehicle body (9) and coupled to a speed reducer (22), the speed reducer (22) including at least one reduction stage (23a, 23b), the at least one reduction stage (23a, 23b) including an output shaft (23c) having a rotational axis parallel to the hinge axis connecting the suspension arm (14) to the vehicle body (9), a lever (24) adapted to transmit motion from the at least one reduction stage (23a, 23b) to the suspension arm (14) by the output shaft (23c) of the at least one reduction stage (23a, 23b), the lever (24) and the output shaft (23c) of the reduction stage (23a, 23b) including or being formed by components configured as substantially rigid bodies, sensor means (26) adapted to detect a parameter indicative of the movement of the suspension arm (14), an electronic control unit (28) adapted to control the torque and angular position of the electromechanical machine (20) of the electromechanical rotary actuator (18) based on a signal transmitted by the sensor means (26), a battery (30) adapted to alternately supply power to and receive power from the electromechanical rotary actuator (18), the electromechanical rotary actuator (18) being operable between an active adjustment state and a damping state In the adjusted state, the electromechanical rotary actuator (18) activates the battery (30) and transmits, via the lever (24), a force that causes relative movement of the suspension arm (14) with respect to the vehicle body (9) to the suspension arm (14), so as to cause the suspension (12) to perform a positive movement. In the damping state, the electromechanical rotary actuator (18) activates the battery (30) and transmits, via the lever (24), a force opposing the relative movement of the suspension arm (14) with respect to the vehicle body (9) to the suspension arm (14), so as to cause the suspension (12) to perform a negative movement, and has a battery (30). The electromechanical rotary actuator (18) is operable between the adjusted state and the damping state according to a command from the electronic control unit (28), and applies movement to the suspension arm (14) having a maximum frequency higher than 5 Hz, or damps the movement of the suspension arm (14) having a maximum frequency higher than 5 Hz. The vehicle further includes a pair (17) of cylindrical members each having at least two telescopically extendable and retractable portions. One of the at least two portions has one end connected to the suspension arm (14) by a joint, and the other of the at least two portions has one end connected to the vehicle body (9) by another joint. The vehicle, wherein the pair (17) of cylindrical members is configured not to substantially exert a damping effect on the operation of the suspension. The vehicle according to claim 1, wherein the pair (17) of cylindrical members is configured to exert a damping effect on the operation of the suspension (12), thereby adding to the damping effect generated by the electromechanical rotary actuator (18). The vehicle according to claim 2, wherein the pair (17) of cylindrical members is configured as a conventional automotive shock absorber.

4. The elastic means (16) A first end of the elastic means (16) is connected to a portion of the pair (17) of cylindrical members attachable to the vehicle body (9). The second end of the elastic means (16) is connected to the portion of the cylindrical pair (17) attached to the suspension arm (14), The vehicle according to any one of claims 1 to 3, wherein the lever (24) is connected to the portion of the cylindrical pair (17) attached to the suspension arm (14).

5. The lever (24) is, A lever (24a) integrated to transmit torsion to the output shaft (23c) of the at least one reduction stage (23a, 23b), A rod (24b) that articulates with the lever (24a) and has one end hinged to the suspension arm (14), or the hub (10), or the portion of the cylindrical pair (17) attached to the suspension arm (14), The vehicle according to any one of claims 1 to 4, wherein the lever (24a) and the rod (24b) are configured as substantially rigid bodies.

6. The speed reducer (22) has a multi-stage planetary gear train, The speed reducer (22) is housed in the housing of the electromechanical rotary actuator (18) integrally attached to the vehicle body (9), Each stage (23a, 23b) of the planetary gear train has a sun gear that meshes with a plurality of planets of a planet carrier, The plurality of planets of the planet carrier mesh with a ring gear on the radially outer side, The planetary gear train is configured such that the input of each stage is the sun gear and the output of each stage is the planet carrier, The vehicle according to any one of claims 1 to 5, wherein the ring gear is fixed and integrated to the housing of the electromechanical rotary actuator (18) so as not to rotate.

7. The speed reducer (22) consists of a two-stage planetary gear train. The planet carrier of the first stage is connected to the lever (24) with torsional rigidity, and the sun gear of the second stage is connected to the shaft of the electromechanical machine (20) with torsional rigidity. The vehicle according to claim 6.

8. The electromechanical rotary actuator (18) is connected to the vehicle body (9) by elastic and damping means (32). The vehicle according to any one of claims 1 to 7.

9. The vehicle according to any one of claims 1 to 8, wherein the electronic control unit (28) is completely integrated inside the electromechanical device (18) and forms an extension in the axial direction of the electromechanical (20).

10. The vehicle according to any one of claims 1 to 9, wherein the axis of rotation of the output shaft (23c) of the at least one reduction stage (23a, 23b) is parallel to, but does not coincide with, the hinge axis of the suspension arm (14) with respect to the vehicle body (9).

11. A method for adjusting the movement of a vehicle suspension, comprising: a) providing a vehicle according to any one of claims 1 to 10; b) detecting, via the sensor means (26), the relative position and relative speed between the vehicle body (9) and the hub (10); c) when the mutual movement between the vehicle body (9) and the hub (10) is detected by the electronic control unit (28), the electromechanical rotary actuator (18) is c1) When the movement of the hub (10) is such that the distance between the hub and the vehicle body (9) tends to decrease with respect to the absolute distance that the hub (10) has from the vehicle body (9) in the neutral state of the static force balance of the suspension (12), supplying current from the battery (30) to the electromechanical rotary actuator (18) to generate torque, the torque being transmitted by the lever (24) to the suspension arm (14) to act on the suspension arm (14) at a maximum frequency F > 5 Hz, and further reducing the distance between the hub (10) and the vehicle body (9) as long as the relative speed between the hub (10) and the vehicle body (9) does not change sign, interrupting the power supply from the battery (3) to the electromechanical rotary actuator (18), causing the electromechanical rotary actuator (18) to function as a generator, and transmitting the generated current (30). c2) When the movement of the hub (10) is such that the distance between the hub and the vehicle body (9) tends to increase with respect to the absolute distance that the hub (10) has from the vehicle body (9) in the neutral state of the static force balance of the suspension (12), supply current from the battery (30) to the electromechanical rotary actuator (18) to generate torque, the torque is transmitted to the suspension arm (14) by the leverage (24) to act on the suspension arm (14) at a maximum frequency F>5 Hz, and as long as the relative speed between the hub (10) and the vehicle body (9) does not change sign, further increase the distance between the hub 10 and the vehicle body 9, interrupt the power supply from the battery (30) to the electromechanical rotary actuator (18), cause the electromechanical rotary actuator (18) to function as a generator, and transmit the generated current to the battery (30), a method having steps.

12. The method according to claim 11, wherein step (b) is performed by an angular position sensor incorporated in the electromechanical (20) and adapted to enable control of torque and speed.

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