Electric actuator device and related road vehicle equipped with position detection system

Abstract

To provide an electric actuator device equipped with a position detection system that is lighter in weight, simpler to assemble, and has improved safety performance.SOLUTION: An electric actuator device 6 includes an electric motor 7 including a stator 8 and a rotor 9 configured to rotate about an axis A according to the power transmitted by a stator, a control unit configured to control the electric motor by feedback control, a position sensing system 11 configured to provide an angular position of the rotor to a control unit, a reading unit 13 including a code surface 14 on which a plurality of codes 15 are fixed, which are integral with the rotor and can be associated with the angular position of the rotor, and an optical or laser sensor element 16 integrated with the stator and arranged to face the code surface 14.SELECTED DRAWING: Figure 2

Description

[Technical Field] 【0001】 [Cross-reference to related patent applications] This patent application claims priority to Italian Patent Application No. 102022000012119, filed June 8, 2022, the entire disclosure of which is incorporated herein by reference. 【0002】 The present invention relates to an electric actuator device equipped with a position detection system, and to a road vehicle equipped with such a device. 【0003】 In particular, but not exclusively, the present invention is advantageously embodied in one or more electric actuators for high performance vehicles, to which explicit reference is made in the following description without any loss of generality. [Background technology] 【0004】 As is well known, the use of electric actuators is now widespread in the field of vehicles (and in general), both in terms of propulsion and comfort, and in particular, all such actuators are usually managed by a dedicated control unit, which works by controlling the position or the speed of said actuators. 【0005】 At least in connection with the electric motors of propulsion systems, angular position transducers are used to carry out the feedback control that is often required for safety reasons, i.e. electromechanical devices are used that provide the absolute or relative position of the rotor of the electric motor to be controlled from time to time, thereby making the feedback control possible. Among these, digital devices, usually called encoders, are known that convert the angular position of a rotating shaft (integral with the rotor of the electric motor to be controlled) into short electrical pulses that must be processed by a signal analysis circuit in the form of a numerically coded digital signal. 【0006】 Furthermore, analogue devices, usually called resolvers, are known, which consist of electromechanical devices for measuring angular displacement, which make it possible to detect the variations in the magnetic induction flux associated with a solenoid as a function of the position of the solenoid itself (integral with the rotor of the electric motor being controlled). 【0007】 Several types of the aforementioned devices have been developed over the years. 【0008】 In any case, encoders are usually used in applications that require a priori reference in that they provide a relative position: they encode the position (and its derivative over time) of the controlled motor rotor in a signal proportional to the displacement. 【0009】 Resolvers, on the other hand, can provide encoding of rotor position in absolute terms, but usually have a significant cost and size, especially since they require the presence of at least a copper circuit (solenoid or printed circuit board) coupled with the magnetic induction flux variations of the machine (i.e. the electric motor to be controlled) and a relative sensor. 【0010】 Furthermore, prior art devices are electromechanical and typically require careful and gentle assembly by an experienced worker. 【0011】 Furthermore, prior art devices require dedicated circuitry in the transducer and within the control unit of the road vehicle. 【0012】 In any event, both of the above solutions, while functional, leave room for improvement according to the applicant. 【0013】 It is generally recognized that there is a need for further weight reduction, simplified assembly, and improved safety performance, as well as optimized cost control. 【0014】 Finally, prior art devices are also expensive in terms of energy, and especially in all-electric vehicles, it is becoming increasingly important to limit energy other than the propulsion component in order to increase the vehicle's autonomy. Summary of the Invention [Problem to be solved by the invention] 【0015】 The object of the present invention is to provide an electric actuator device with a position detection system and a road vehicle thereof, which device at least partially avoids the above-mentioned drawbacks and at the same time can be realized simply and inexpensively. [Means for solving the problem] 【0016】 According to the present invention, there is provided an electric actuator device comprising a position detection system, and a road vehicle thereof, according to the following independent claim and preferably any of the claims directly or indirectly dependent thereon. 【0017】 The claims describe preferred embodiments of the invention and form an integral part of this specification. [Brief explanation of the drawings] 【0018】 The following description, given by way of non-limiting example and with reference to the accompanying drawings, provides a better understanding of embodiments of the invention. 【0019】 [Figure 1] 1 is a perspective schematic view, with details removed for clarity, of a possible embodiment of a road vehicle according to the invention; FIG. [Figure 2] 1 is a perspective schematic cross-sectional view of an electric actuator device according to a first embodiment, with details removed for clarity; FIG. [Figure 3] FIG. 3 is a detailed view of FIG. 2. [Figure 4] FIG. 10 is a schematic perspective cross-sectional view of an electric actuator device according to a second embodiment, with details removed for clarity; [Figure 5] FIG. 5 is a detailed view of FIG. DETAILED DESCRIPTION OF THE INVENTION 【0020】 In Figure 1, 1 generally indicates a road vehicle comprising two front wheels 2 and two rear wheels 3, at least one pair (or all) of which receive drive torque from a motor propulsion system 4. This motor propulsion system 4 may be exclusively thermal (i.e. comprising only an internal combustion engine), hybrid (i.e. comprising an internal combustion engine and at least one electric motor), or electric (i.e. comprising only one or more electric motors). 【0021】 Preferably, the road vehicle 1 comprises a passenger compartment 5 adapted to accommodate at least one driver and preferably one or more passengers. 【0022】 The same reference numbers and letters in the figures indicate the same elements or components having the same function. 【0023】 In the context of this specification, the term "second" component does not imply the presence of a "first" component. These terms are actually used as labels to improve clarity and should not be understood in a limiting sense. 【0024】 The elements and features shown in the various preferred embodiments, including the drawings, can be combined or separated from one another without departing from the scope of protection of the present application as described below. 【0025】 The road vehicle 1 comprises at least one electric actuator device 6 provided on an electric motor 7 . 【0026】 The electric motor 7 comprises a stator 8 and a rotor 9, the rotor 9 being configured to rotate about a rotation axis A in response to (electric) power transmitted by the stator. Stators are well known and therefore will not be described in further detail. In particular, the electric motor 7 can be any type of electric machine (e.g., brushless motor, permanent magnet motor, induction motor, synchronous motor, asynchronous motor, etc.). 【0027】 The road vehicle 1 comprises an electronic control unit ("ECU") 10 configured, inter alia, to control the electric motor 7 by feedback (i.e. closed loop according to known control algorithms, which will therefore not be described in further detail). Physically, the control unit 10 may consist of a single device or several devices separated from each other and communicating via a local network (CAN, Ethernet, etc.) of the road vehicle 1. 【0028】 In order to perform the aforementioned feedback control, the device 6 comprises a position detection system 11 configured to provide the angular position of the rotor 9 (and hence the motor shaft 12 connected thereto in accordance with known techniques) to the control unit 10. 【0029】 Advantageously, the device 6 comprises a reading unit 13 integrated into the rotor 9 and provided with a (non-perforated) code surface 14 on which are fixed (in particular printed) a number of codes 15 that can be associated with the angular position of the rotor 9. 【0030】 The device 6 further comprises an optical or laser sensor element 16 arranged integrally with the stator 8 and facing the symbol surface 14 . 【0031】 Advantageously, but not exclusively, the reference symbols 15 extend radially relative to the rotor 9 and are separated from one another, in other words, the reference symbols 15 are arranged in rows in a concave-convex pattern. 【0032】 Advantageously, but not exclusively, the symbol 15 is not sector-shaped. 【0033】 Preferably, but not exclusively, the references 15 determine absolute references for the positions of the rotor 9, in particular they are all different from one another. 【0034】 Preferably, the code surface 14 is a seamless surface, i.e. a surface without through holes, which allows the use of SPAD (Single Photon Avalanche Diode) / CMOS (Complementary Metal Oxide Semiconductor) chips as follows. In addition, this avoids holes that would change the density of the rotor 9, which would impair the inertia of the rotor 9. 【0035】 According to some preferred, non-limiting embodiments, such as those shown in Figures 2-5, the sensor element 16 is a photodetector 17 (i.e., a device capable of detecting electromagnetic radiation and outputting a signal having a current strength or potential difference proportional to the intensity of the detected radiation). 【0036】 In some preferred, non-limiting cases, the sensor element 16 comprises one or more single-photon detection photodetectors 17 (known by the acronym SPAD). Preferably, the sensor element 16 is in the form of a SPAD / CMOS chip. This allows the sensor element 16 to read the information contained in the code surface 14 very quickly, even in dark conditions inside the device 6. This avoids adding weight to the road vehicle. Furthermore, this technology, which is not used today in vehicle applications, allows the code to be laser printed on the rotor without affecting the rotor's mechanical performance, ensuring sufficient durability of the code 15. 【0037】 In another non-limiting, not shown, case, the sensor element 16 is a miniature camera configured to continuously detect images of the code surface 14 . 【0038】 Advantageously, but not exclusively, the symbols 15 are arranged equidistant from one another in the radial direction, in particular relative to the axis of rotation A of the rotor 9 . 【0039】 Preferably, the code 15 is realized by laser printing. 【0040】 According to some preferred, non-limiting embodiments, the reading portion 13 is made of metal. 【0041】 In particular, the reading part 13 is made integral with the rotor 9 or with the motor shaft 12 of the electric motor 7. More precisely, the reading part is an existing part of the rotor 9 or of the shaft 12. This allows for maximum simplicity of assembly, which is limited to fixing the sensor element 16 in the correct installation position. 【0042】 2 and 3, the reading portion 13 comprises (or is) an end 19 of the shaft 12 that is integral with the rotor 9 of the electric motor 7. This simplifies the mounting of the sensor element 16 in that the end 19 extends outside the rotor 9 (i.e., extends from one of the bases of the cylindrical volume defined by the rotor 9). 【0043】 Alternatively or additionally, the reading unit 13 comprises (or is) the base disk 20 of the rotor 9 of the electric motor 7, since generally more sensor elements 16 can be combined for greater accuracy, which results in a larger code surface and therefore a greater number of rows 18. 【0044】 In some non-limiting cases, such as the embodiment of FIGS. 2 and 3, the code surface 14 is parallel to the axis of rotation A of the rotor 9. 【0045】 In other non-limiting cases, such as the embodiment of FIGS. 4 and 5, the code surface 14 is transverse, specifically perpendicular, to the axis of rotation A of the rotor 9 . 【0046】 Regardless of the orientation of the code surface 14, the sensor element 16 is mounted so that it appears perpendicular to the code surface 14 to optimize reading of the code 15. 【0047】 According to some preferred, non-limiting embodiments, each code 15 includes rows 18 coded in binary format. In particular, the term "binary" refers to any coding that provides two different conditions. For example, a code 15 is binary if the rows 18 are peaks and valleys, or if the values ​​0 and 1 are printed, or if they are different figures. 【0048】 According to a further non-limiting and non-exemplary embodiment, the code 15 includes a barcoded or alphanumeric coded line 18 . 【0049】 Advantageously, although not necessarily, each coded row 18 corresponds to a particular angular position of the rotor 9 of the electric motor 7, as can be seen from FIGS. 【0050】 In particular, the reading unit 13 has at least one row per rotation angle, in other words, the reading unit 13 comprises at least 360 rows, preferably at least 720 rows. Obviously, increasing the number of rows improves the resolution of the position detection system. 【0051】 According to some preferred, non-limiting embodiments, the actuator device 6 is part of the propulsion system 4. In other words, the electric motor 7 is configured to deliver a drive torque to at least one or both of the front wheels 2 and / or one or both of the rear wheels 3. 【0052】 Alternatively or in addition, the actuator device 6 is configured to operate ancillary devices that are not essential for the operation of the road vehicle 1, such as, but not limited to, windows, doors, seats, and any feedback-controlled actuators. 【0053】 In particular, the actuator device 6 can also be used without problem to actuate an active suspension, for example of the type described in patent application no. 102022000007496 of the applicant. 【0054】 When using the sensor elements 16, the control unit 10 processes the signal detected by the sensor elements 16 and thus the exact angular position of the rotor 9, preferably in real time, by decoding the photons sensed by a photodetector 17, for example of the SPAD type. The unit 10 can centrally control the mode of the electric motor 7 as soon as the signal is detected, for example by implementing known control algorithms such as PID (Proportional-Integral-Differential), feedforward, etc. 【0055】 Although the invention described above makes particular reference to a very precise example of embodiment, the invention should not be considered as limited to this example of embodiment, since all variations, modifications or simplifications covered by the appended claims, such as, for example, different types of road vehicles (e.g. with hybrid drive), different forms of code surfaces, different row positions, different reading technologies, etc., are included within their scope. 【0056】 The actuator device and vehicle described above have many advantages. 【0057】 First, they allow the elimination of encoders / resolvers and their associated circuitry, allowing for lighter road vehicle structures and therefore improved performance for the same displayed output. 【0058】 Furthermore, assembly of the actuator arrangement can be simplified since the angular position sensing system is built directly into the engine and does not require special measures on the part of an experienced operator. 【0059】 A further advantage of the present invention is that due to the existence of specific code rows for specific angular positions, the absolute position of the controlled electric motor can be detected mechanically in a simpler and more reliable way, thus avoiding any errors when powering up the road vehicle and reading the position, thereby ensuring that the vehicle always moves according to the driver's wishes, thus protecting the safety of the driver himself, the vehicle and any individuals around the vehicle. 【0060】 Furthermore, the present invention allows for the control of vehicle and all other types of electric motors in an economical, simple and safe manner. 【0061】 Finally, the use of laser technology, such as SPAD photodetectors, allows for a significant reduction in computation times compared to optical devices, thus offering the possibility of increasing the number of lines read, i.e. the number of detectable positions, and therefore the accuracy of detection. [Explanation of symbols] 【0062】 1 Road vehicles 2 front wheels 3 rear wheels 4 Propulsion System 5 Cabin 6 Actuator device 7 Electric motor 8 Stator 9 rotor 10. Control Unit 11 Detection System 12 shafts 13 Reading unit 14 code area 15 sign 16 sensor elements 17 Photodetector 18 rows 19 End 20 base disks A rotation axis

Claims

[Claim 1] Electric actuator device (6), An electric motor (7) comprises a stator (8) and a rotor (9) configured to rotate around an axis (A) in accordance with the power transmitted by the stator (8), A control unit (10) is configured to control the electric motor (7) by feedback control, The system includes a position detection system (11) configured to provide the control unit (10) with the angular position of the rotor (9), The electric actuator device (6) A reading unit (13) is provided with a code surface (14) on which a plurality of codes (15) that can be associated with the angular position of the rotor (9) are fixed, which is integrated with the rotor (9). The system further comprises an optical sensor element or laser sensor element (16) integrated with the stator (8) and positioned to face the code surface (14), The electric actuator device (6) comprises one or more single-photon detection type SPAD (Single Photon Avalanche Diode) photodetectors (17) as the sensor element (16). [Claim 2] The apparatus (6) according to claim 1, wherein the sensor element (16) is a photodetector (17). [Claim 3] The apparatus (6) according to claim 2, wherein the surface 14 indicated by the reference numeral is a seamless surface, that is, a surface without through holes. [Claim 4] The apparatus (6) according to claim 1, wherein the plurality of reference numerals (15) are realized by laser printing. [Claim 5] The apparatus (6) according to claim 1, wherein each of the aforementioned reference numerals (15) comprises a binary encoded line (18). [Claim 6] The apparatus (6) according to claim 5, wherein each of the rows (18) of the reference numeral (15) corresponds to a specific angular position of the rotor (9) of the electric motor (7). [Claim 7] The apparatus (6) according to claim 6, wherein the reading unit (13) has at least one row (18) for each angle of the rotation angle. [Claim 8] The apparatus (6) according to claim 1, wherein the reading unit (13) is made of metal. [Claim 9] The apparatus (6) according to claim 8, wherein the reading unit (13) is integrally formed with the rotor (9) of the electric motor (7) or its rotating shaft (12). [Claim 10] The apparatus (6) according to claim 1, wherein the reading unit (13) includes an end portion (19) of the shaft (12) that is integrated with the rotor (9) of the electric motor (7). [Claim 11] The apparatus (6) according to claim 1, wherein the reading unit (13) comprises the base disk (20) of the rotor (9) of the electric motor (7). [Claim 12] The apparatus (6) according to claim 1, wherein the surface (14) of the reference numeral is parallel to the rotation axis (A) of the rotor (9). [Claim 13] The apparatus (6) according to claim 1, wherein the surface of the reference numeral (14) crosses the rotation axis (A) of the rotor (9). [Claim 14] The apparatus (6) according to claim 13, wherein the surface of the reference numeral (14) is perpendicular to the rotation axis (A) of the rotor (9). [Claim 15] Road vehicle (1), Four wheels (2, 3) with at least one pair of wheels (2, 3) being driven, A road vehicle (1) characterized by comprising at least one of the devices (6) described in claim 1. [Claim 16] The vehicle (1) according to claim 15, wherein the actuator device (6) is part of a system (4) that electrically propels the road vehicle (1). [Claim 17] The vehicle (1) according to claim 15, wherein the actuator device (6) is configured to operate an ancillary device and / or at least one active suspension.

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