Steering road sensing motor system actuator unit

Abstract

The present invention discloses a steering road sense motor system execution unit, including: a road sense upper column assembly penetrates into an upper housing to form an interference fit, a first end of a gear shaft forms a transition fit with a steering wheel, a second end of a gear shaft passes through an inner ring of a bearing in a lower housing through a clearance fit, and a second end of the gear shaft is connected to a direct drive motor through a flexible connector; the lower housing is formed into a variable diameter structure with large ends and small middle, a pressure block hole is formed on the side wall of its small diameter section, and a bearing is fixed in its second large diameter section; a torque sensor is located in the first large diameter section, and the torque sensor collects the driver's hand force and sends it to a direct drive motor controller through a Can command; a pressure block assembly is connected in the pressure block hole; and the direct drive motor controller sequentially controls the road sense motor according to the Can command. The present invention can omit complex mechanical transmission, improve its transmission efficiency, and adopt the selective switching of the SVPWM seven-segment non-conduction time, so that the output three-phase voltage is reduced at different times, and the voltage harmonic amplitude is reduced, and the current fluctuation and torque fluctuation are suppressed.

Description

Technical Field

[0001] The present invention relates to the field of automobiles, and in particular to an execution unit of a steering road sensing motor system. Background Art

[0002] Autonomous driving technology is the future development trend of the automotive industry. It has formed a national strategy and is expected to be commercialized around 2025, which will redefine the automotive industry. Autonomous driving involves several major system perceptions, and the decision-making and execution in the execution have relatively high technical barriers, which has become a hot topic of research. The execution system is generally divided into wire-controlled steering and wire-controlled braking. Among them, the wire control system includes two major systems: the upper-level road sense feedback and the lower-level redundant function safety execution; this application mainly designs the upper-level road sense feedback system, and the road sense simulator includes a steering wheel assembly, a steering wheel angle sensor, a torque sensor, and a steering wheel return torque motor. The main function of the road sense simulator is to convert the driver's steering intention (by measuring the steering wheel angle) into a digital signal and transmit it to the main controller. At the same time, the main controller sends a control signal to the steering wheel return motor to generate a steering wheel return torque to provide the driver with corresponding road sense information.

[0003] The existing steering road sensing motor system execution unit has defects such as complex mechanical transmission structure, low transmission efficiency, and unstable control that need to be solved. Summary of the invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention, which are all simplifications of the prior art in the field, and will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0005] The technical problem to be solved by the present invention is to provide a steering road sensing motor system execution unit which has a simple structure, can improve the torque / angle precision, and can suppress current fluctuation and torque fluctuation.

[0006] In order to solve the above technical problems, the present invention provides an execution unit for a steering road sensing motor system, comprising:

[0007] The road-sensing upper column assembly 2 is inserted into the upper housing 10 to form an interference fit, the first end of the gear shaft 11 forms a transition fit with the steering wheel 1, the second end of the gear shaft 11 passes through the inner ring of the bearing in the lower housing through a clearance fit, and the second end of the gear shaft 11 is connected to the direct-drive motor 4 through a flexible connector;

[0008] The lower housing 12 is formed into a variable diameter structure with large ends and a small middle. A pressing block hole is formed on the side wall of the small diameter section, and a bearing 8 is fixed in the second large diameter section.

[0009] The torque sensor 7 is located in the first large diameter section and is mounted on the gear shaft 11 close to the lower housing to form an interference fit. The torque sensor 7 collects the driver's hand force and sends it to the direct drive motor controller 5 through the Can command.

[0010] A pressing block assembly 6, which is rotatably connected in the pressing block hole;

[0011] The direct drive motor controller 5 divides the motor voltage into 6 vector spaces through SVPWM seven-segment space vector pulse width modulation, and divides it into 6 sectors in turn. Each sector calculates the PWM time of the switch switching to obtain different durations. It controls the switching of the road sense motor voltage at different times in turn according to the Can instruction.

[0012] Optionally, the steering road sensing motor system execution unit is further improved, and the flexible connection member is a coupling 19.

[0013] Optionally, the steering road sensing motor system execution unit is further improved, and the pressing block assembly 6 includes:

[0014] An adjusting nut 6.1, which is threadedly connected to the hole of the pressure block;

[0015] An elastic member 6.2, which is located and compressed between the pressure block and the adjusting nut;

[0016] The buffer member 6.3 is located between the adjusting nut and the pressure block.

[0017] Optionally, the steering road sense motor system execution unit is further improved, and the two large ends of the variable diameter structure are formed into a trumpet shape.

[0018] Optionally, the steering road sensing motor system execution unit is further improved, and the bearing 8 is connected to the lower housing 12 by a shrink-fit process.

[0019] Optionally, the steering road sense motor system execution unit is further improved, and the bearing is a 4P bearing.

[0020] Optionally, the steering road sensing motor system execution unit is further improved, and the base of the direct drive motor controller 5 is integrated on the direct drive motor 4 body.

[0021] Optionally, the steering road sensing motor system execution unit is further improved so that one switch performs two actions within one switching cycle.

[0022] The assembly process of the present invention is as follows:

[0023] 1. Transitionally fit the steering wheel 1 with the road-sensing upper column assembly 2, and at the same time, the upper column assembly 2 and the upper housing 10 are press-fitted with reference to Figure 3As shown, at this time, the upper column assembly 2 and the steering wheel 1 have formed a parts assembly, the TAS torque sensor 7 is sleeved on the parts assembly, and a small interference fit is performed on the gear shaft 11 at the end of the parts assembly. The riveting process is adopted in the middle, that is, the rotor and stator of the torque sensor are matched with the gear shaft together and riveted;

[0024] 2. Reference Figure 6 and Figure 7 As shown, the lower housing 12 is designed with trumpet-shaped ends, and the TAS torque sensor 7, the pressure block assembly 6 and the coupling 19 are integrated into the lower housing 12 to form a mechanism, and the robustness of the mechanism is improved; the outer ring of the 4P bearing 8 and the housing are pressed onto the lower housing through the shrink-fit technology in the lower housing to serve as a lower housing-bearing assembly;

[0025] 3. The gear shaft of the road-sensing upper column assembly is passed through the inner ring of the bearing of the lower housing-bearing assembly through clearance fit, and then the upper housing and the lower housing are fastened with M6 screws, with the inner ring of the bearing as the base hole system, matching the gear shaft to achieve coaxiality; then use its locking nut 9 to lock it to the inner ring of the 4P bearing, and eliminate the axial clearance of the system by rotating the locking nut, and make axial clearance compensation for the entire mechanism; at the same time, the pressure block 6 is rotated inward through the threaded hole on the side of the lower housing 12 to compensate for the radial clearance of the gear shaft 11; the trumpet-shaped design structure at both ends is designed to connect the TAS torque sensor 7, the radial compensation between the pressure block 6 and the gear shaft 11, and the axial compensation between the 4P bearing 8 and the locking nut 9, so that the functions of the three places are connected into a whole, which is more compact in space;

[0026] 4. Press the end of the gear shaft 11 into the motor coupling assembly 19, and then connect the motor coupling assembly 19 with the direct drive motor 4 ( Figure 8 The direct drive motor unit assembly shown in the figure) is matched before, and the direct drive motor 4, the installation stop is designed with a sealing ring 15, and a suitable tolerance band is selected, and the lower shell part is matched through a base hole system. The cooperation between the two achieves a sealing effect through the compression amount of the sealing ring;

[0027] The hardware structure of the present invention is formed by the above assembly process, and the above hardware structure can bring the following technical effects:

[0028] 1. The intermediate shaft is directly connected to the direct drive motor with a flexible connector. The pressure block acts on the gear shaft of the intermediate shaft. A buffer (such as a buffer O-ring) is added between the adjustment nuts of the pressure block parts to increase the spring stiffness of the pressure block. The working pressure can reach about 500N, eliminating the radial clearance of the gear shaft. Figure 5 As shown;

[0029] 2. Through the shell design, the 4P bearing and the shell are connected by the shrink fit process. The inner hole of the 4P bearing and the gear shaft are matched with each other. The lockability of the locking nut is used to offset and compensate the axial clearance. Figure 4 As shown;

[0030] 3. The integrated direct drive motor PPK adopts the integrated type of motor and controller ECU, and the base of the controller is completely integrated on the motor body, shortening the layout space of its PPK products. Figure 8 As shown;

[0031] 4. The direct-drive motor adopts a multi-pole rotor design. When the motor output power remains unchanged, the motor speed is reduced and the torque is increased through the motor's own pole-changing speed regulation principle to achieve low-speed and high-torque. At the same time, some parts of the motor are made into an integrated structure with the bearing chamber to achieve a small-volume structural space layout;

[0032] It adopts SVPWM seven-segment space vector pulse width modulation, which is two different switching of seven segments. The voltage is divided into 6 vector spaces, which are divided into 6 sectors in turn; each sector calculates the switching PWM time of MOS to obtain different durations, and controls the switching of the road sense motor voltage at different times in turn; due to the low speed and high torque of the motor, the iq current closed loop of the software algorithm, and RPS detects its rotor angle signal information; the soft voltage control adopts the anti-Park Uα and Uβ SVPWM seven-segment. Since a switch performs two actions in one switching cycle, the advantage is to reduce the voltage harmonic amplitude and suppress current fluctuations. At the same time, the torque fluctuation of the road sense system is further suppressed, and the control is more stable and the feel is smoother.

[0033] The implementation method adopted by the present invention is based on a road sense simulation system. The driver provides hand force, the motor is directly connected to the column mechanism, and the torque sensor is mounted on the gear shaft to collect the hand force. The ECU receives the command and sends it to the motor (the integrated direct drive motor uses the ECU to power on, the software sends the iq current command, and the torque is directly output to drive the motor through the torque coefficient of the motor itself). The iq current command of weak magnetic control is used to convert the motor torque. The voltage is switched at different times, and the voltage of the motor at different times is fed back to drive the torque of the motor at different voltage moments. The mechanical system is directly connected to the motor spline shaft through a spline connector in the middle, which can omit complex mechanical transmission and improve its transmission efficiency. The SVPWM seven-segment non-passing time selection switching is adopted to reduce the output three-phase voltage at different times, and the voltage harmonic amplitude is reduced, which suppresses current fluctuations and torque fluctuations, and the cost of the entire system is effectively controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings of the present invention are intended to illustrate the general characteristics of the methods, structures and / or materials used in specific exemplary embodiments of the present invention, and to supplement the description in the specification. However, the drawings of the present invention are schematic diagrams not drawn to scale, and thus may not accurately reflect the precise structure or performance characteristics of any given embodiment, and the drawings of the present invention should not be interpreted as limiting or restricting the range of values ​​or properties covered by the exemplary embodiments of the present invention. The present invention is further described in detail below in conjunction with the drawings and specific embodiments:

[0035] Figure 1 The first embodiment of the present invention is schematically shown in FIG. Figure 1 .

[0036] Figure 2 The first embodiment of the present invention is schematically shown in FIG. Figure 2 .

[0037] Figure 3 The first embodiment of the present invention is schematically shown in FIG. Figure 3 .

[0038] Figure 4 The first embodiment of the present invention is schematically shown in FIG. Figure 4 .

[0039] Figure 5 It is a cross-sectional view of a pressing block assembly of the present invention.

[0040] Figure 6 It is a schematic diagram of the lower shell structure of the present invention.

[0041] Figure 7 It is a cross-sectional view of the lower shell of the present invention.

[0042] Figure 8 It is a schematic diagram of the direct drive motor unit assembly of the present invention.

[0043] Fig. 9 This is a schematic diagram of the SVPWM seven-segment distribution, showing two different switching modes of the seven-segment type.

[0044] Fig.10 This is a schematic diagram of the first sector judgment.

[0045] Fig.11 This is a schematic diagram of the calculation of the two states of the first sector switching time.

[0046] Description of Reference Numerals

[0047] 1- Steering wheel

[0048] 2-Road sense upper column assembly

[0049] 3-Road sense lower column assembly

[0050] 4-Direct drive motor

[0051] 5-Controller

[0052] 6-Block assembly

[0053] 6.1-Adjusting nut

[0054] 6.2-Elastic parts

[0055] 6.3-Buffer

[0056] 7-Torque sensor

[0057] 8-Bearing

[0058] 9-Lock nut

[0059] 10-Upper shell

[0060] 11-Gear shaft

[0061] 12-Lower housing

[0062] 13-Motor housing

[0063] 14-ECU connector

[0064] 15-Motor sealing ring

[0065] 16-Motor rotor assembly

[0066] 17-Motor stator assembly

[0067] 18-Motor and ECU integrated base assembly

[0068] 19-Motor coupling assembly. DETAILED DESCRIPTION

[0069] The following is an explanation of the embodiments of the present invention by specific specific embodiments, and those skilled in the art can fully understand other advantages and technical effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and the details in this specification can also be applied based on different viewpoints, and various modifications or changes can be made without deviating from the general design concept of the invention. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. The following exemplary embodiments of the present invention can be implemented in a variety of different forms and should not be interpreted as being limited to the specific embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary specific embodiments to those skilled in the art. It should be understood that when an element is referred to as "connected" or "coupled" to another element, the element can be directly connected or coupled to another element, or there can be an intermediate element. The difference is that when an element is referred to as "directly connected" or "directly coupled" to another element, there is no intermediate element. In all figures, the same reference numerals always represent the same element. As used herein, the term "and / or" includes any combination and all combinations of one or more related listed items.

[0070] First embodiment;

[0071] refer to Figure 1-Figure 4 As shown, the present invention provides an execution unit for a steering road sensing motor system, comprising:

[0072] The road-sensing upper column assembly 2 is inserted into the upper housing 10 to form an interference fit, the first end of the gear shaft 11 forms a transition fit with the steering wheel 1, the second end of the gear shaft 11 passes through the inner ring of the bearing in the lower housing through a clearance fit, and the second end of the gear shaft 11 is connected to the direct-drive motor 4 through a flexible connector, and the flexible connector is a coupling 19;

[0073] The lower shell 12 is formed into a variable diameter structure with large ends and a small middle, and a pressure block hole is formed on the side wall of the small diameter section, and a bearing 8 is fixed in the second large diameter section; optionally, the bearing is a 4P bearing, and the bearing 8 is connected to the lower shell 12 by a shrink sleeve process. The two large ends of the variable diameter structure are formed into a trumpet shape, refer to Figure 6 and Figure 7 As shown;

[0074] The torque sensor 7 is located in the first large diameter section and is mounted on the gear shaft 11 close to the lower housing to form an interference fit. The torque sensor 7 collects the driver's hand force and sends it to the direct drive motor controller 5 through the Can command.

[0075] A pressing block assembly 6, which is rotatably connected in the pressing block hole;

[0076] The direct drive motor controller 5 is integrated on the direct drive motor 4 to form a direct drive motor unit assembly reference Figure 8 As shown;

[0077] like Fig. 9 The SVPWM seven-segment schematic diagram shown shows two different switching of the seven-segment type. The motor voltage is divided into 6 vector spaces through the SVPWM seven-segment space vector pulse width modulation, which is divided into 6 sectors in turn. The PWM time of the switch switching is calculated for each sector to obtain different durations. Due to the low speed and high torque of the motor, the iq current closed loop of the software algorithm, and the RPS detects its rotor angle signal information; the soft voltage control adopts the SVPWM seven-segment type of Uα and Uβ of the anti-Park. Since a switch performs two actions in one switching cycle, the voltage harmonic amplitude can be reduced and the current fluctuation can be suppressed. At the same time, the torque fluctuation of the road feel system is further suppressed, and the control is more stable and the feel is smoother.

[0078] To further illustrate the execution logic of the motor controller of the present application, the switching of the two timers in the exemplary first sector is described as follows:

[0079] refer to Fig. 9 The SVPWM seven-segment schematic diagram shows two different switching modes of the seven-segment type. Fig.10 The first sector judgment diagram shown is shown in FIG. Fig.11 The figure shows the switching diagram of the two timers in the first sector; there are two types of time switching of the seven segments in the first sector of SVPWM, and the means of realizing the two states can achieve the same effect; the vector diagram first determines the voltage vector position of each sector, and after determining the position, generates the switching of the voltage vector at different times in each sector, so that each sector generates three PWM signal waves according to the switching of the voltage at different times (the attached figure is the calculation of the two states of the switching time of the first sector), and the voltage in each sector approaches a sine wave according to the switching of high level and low level; the faster the switching time, the smoother the sine wave.

[0080] Second embodiment;

[0081] refer to Figure 5 As shown, the present invention provides a first embodiment of the steering road sensing motor system execution unit, the pressing block assembly 6 includes:

[0082] An adjusting nut 6.1, which is threadedly connected to the hole of the pressure block;

[0083] An elastic member 6.2, which is located and compressed between the pressure block and the adjusting nut;

[0084] The buffer member 6.3 is located between the adjusting nut and the pressure block.

[0085] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. It will also be understood that, unless expressly defined herein, terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not interpreted in an ideal or overly formal sense.

[0086] The present invention has been described in detail above through specific implementation modes and embodiments, but these do not constitute limitations of the present invention. Without departing from the principles of the present invention, those skilled in the art may also make many variations and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. A steering road sensing motor system execution unit, characterized in that: include: A road-sensing upper column assembly (2) is inserted into the upper housing (10) to form an interference fit, a first end of the gear shaft (11) forms a transition fit with the steering wheel (1), a second end of the gear shaft (11) passes through the inner ring of the bearing in the lower housing through a clearance fit, and the second end of the gear shaft (11) is connected to the direct-drive motor (4) through a flexible connector; The lower shell (12) is formed into a variable diameter structure with large ends and a small middle, a pressing block hole is formed on the side wall of the small diameter section, and a bearing (8) is fixed in the second large diameter section; A torque sensor (7) is located in the first large diameter section and is mounted on a gear shaft (11) close to the lower housing to form an interference fit. The torque sensor collects the driver's hand force and sends it to the direct drive motor controller (5) via a Can command. A pressing block assembly (6) rotatably connected in the pressing block hole; The direct drive motor controller (5) divides the motor voltage into 6 vector spaces through SVPWM seven-segment space vector pulse width modulation, and divides it into 6 sectors in turn. Each sector calculates the PWM time of the switch switching to obtain different durations, and controls the switching of the road sense motor voltage at different times in turn according to the Can instruction.

2. The steering road sensing motor system execution unit according to claim 1, characterized in that: The flexible connection piece is a coupling (19).

3. The steering road sensing motor system execution unit according to claim 1, characterized in that: The pressing block assembly (6) comprises: An adjusting nut (6.1) which is threadedly connected to the hole of the pressure block; An elastic member (6.2) which is located and compressed between the pressure block and the adjusting nut; A buffer (6.3) is located between the adjusting nut and the pressure block.

4. The steering road sensing motor system execution unit according to claim 1, characterized in that: The two large ends of the diameter-changing structure are formed in a trumpet shape.

5. The steering road sensing motor system execution unit according to claim 1, characterized in that: The bearing (8) and the lower housing (12) are connected by a shrink-fit process.

6. The steering road sensing motor system execution unit according to claim 4, characterized in that: The bearing is a 4P bearing.

7. The steering road sensing motor system execution unit according to claim 1, characterized in that: The direct drive motor controller (5) base is integrated on the direct drive motor (4) body.

8. The steering road sensing motor system execution unit according to any one of claims 1 to 7, characterized in that: In one switching cycle, a switch performs two actions.

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