Chassis dynamometer

Abstract

This disclosure aims to provide a chassis dynamometer that generates a steering wheel restoring force when the vehicle is in a steering turn state to perform a vehicle driving test. The turning model controller (21) in the chassis dynamometer (1) of this disclosure performs a turning determination process and a turning command angle calculation process based on left turning information (S1L) and right steering angle information (S1R). The turning determination process is a process that determines whether the vehicle (60) is in a steering turn state or a straight-ahead state. The turning command angle calculation process is a process that calculates the left turning command angle (θlv) and the right turning command angle (θrv) for controlling the roller turning mechanism (DM1) when the vehicle is in a steering turn state. The left turning command angle (θlv) is smaller than the left steering angle (θl) indicated by the left steering angle information (S1L), and the right turning command angle (θrv) is smaller than the right steering angle (θr) indicated by the right steering angle information (S1R).

Description

Technical Field

[0001] The present disclosure relates to a chassis dynamometer used for various driving tests of vehicles.

Background Art

[0002] Conventional chassis dynamometers are used when conducting driving tests on vehicles (automobiles) and include a roller device as a main component.

[0003] As a conventional chassis dynamometer, for example, there is a chassis dynamometer disclosed in Patent Document 1.

[0004] The conventional chassis dynamometer disclosed in Patent Document 1 includes a left-tire sensor for measuring the tire break angle of the left tire and a right-tire sensor for measuring the tire break angle of the right tire.

[0005] The conventional chassis dynamometer having the above configuration performs a roller turning operation of turning the left-tire and right-tire roller devices at the same angle as the tire break angle of each of the left and right tires, and conducts a test in a steering turning state of the vehicle.

Prior Art Documents

[0009] This disclosure was made to solve the above-mentioned problems, and aims to provide a chassis dynamometer that can generate a steering wheel restoring force when the vehicle is in a steering turn state and perform a vehicle driving test. [Means for solving the problem]

[0010] The chassis dynamometer of the present disclosure is a chassis dynamometer having four rollers on which four tires of a vehicle are mounted, wherein the four tires include a front wheel pair and a rear wheel pair, one of the front wheel pair and the rear wheel pair is defined as a Type 1 tire pair and the other as a Type 2 tire pair, the Type 1 tire pair includes a Type 1 left tire and a Type 1 right tire arranged on the left and right sides, and the Type 2 tire pair includes a Type 2 left tire and a Type 2 right tire arranged on the left and right sides, front The four rollers include a first-type left roller on which the first-type left tire is mounted, a first-type right roller on which the first-type right tire is mounted, a second-type left roller on which the second-type left tire is mounted, and a second-type right roller on which the second-type right tire is mounted. The chassis dynamometer includes a steering angle detection mechanism that detects left steering angle information indicating the left tire steering angle, which is the angle of the first-type left tire with respect to the reference direction, and right steering angle information indicating the right tire steering angle, which is the angle of the first-type right tire with respect to the reference direction, and the average steering angle and the right steering angle. The system includes a turning model controller that performs a turning determination process to determine whether the vehicle's driving state is a steering turn or a straight-ahead state based on a comparison result with the determined tire angle, wherein the average steering angle is calculated based on the left tire turning angle indicated by the left steering angle information and the right tire turning angle indicated by the right steering angle information, and the turning model controller performs a turning command angle calculation process when the turning determination process determines that the vehicle's driving state is a steering turn, and the turning command angle calculation process The process involves calculating a left turn command angle based on the left steering angle information and a right turn command angle based on the right steering angle information, wherein the left turn command angle is smaller than the left tire turning angle indicated by the left steering angle information, and the right turn command angle is smaller than the right tire turning angle indicated by the right steering angle information. The chassis dynamometer further includes a roller turning mechanism that performs a roller turning process that drives the first type left roller to turn based on the left turn command angle and drives the first type right roller to turn based on the right turn command angle. [Effects of the Invention]

[0011] The turning model controller in the chassis dynamometer of this disclosure can accurately determine whether the vehicle is in a steering-turn state or a straight-ahead state by performing a turning determination process based on a comparison result between the average steering angle and the straight-ahead determination tire angle.

[0012] The turning model controller in the chassis dynamometer of this disclosure performs a turning command angle calculation process to calculate the left turning command angle and the right turning command angle. The left turning command angle is smaller than the left tire turning angle, and the right turning command angle is smaller than the right tire turning angle.

[0013] Therefore, the chassis dynamometer of this disclosure can perform vehicle driving tests by generating a steering wheel restoring force when the vehicle is in a steering turn state.

[0014] As a result, the chassis dynamometer of this disclosure can accurately perform vehicle driving tests when the vehicle is in a steering / turning state.

[0015] The purpose, features, aspects, and advantages of this disclosure will become clearer from the following detailed description and accompanying drawings. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic perspective view showing the configuration of the chassis dynamometer of this embodiment after the vehicle has been mounted. [Figure 2] Figure 2 is a schematic diagram illustrating the displacement sensor and its surroundings in the chassis dynamometer of this embodiment. [Figure 3] Figure 3 is an explanatory diagram schematically showing the AA section of Figure 2. [Figure 4] Figure 4 is a schematic diagram illustrating the configuration of the roller rotation drive unit. [Figure 5] Figure 5 is a schematic diagram illustrating the contents of the distance measurement area provided on the tire. [Figure 6]FIG. 6 is a flowchart showing a method for acquiring steering angle information by a displacement sensor. [Figure 7] FIG. 7 is an explanatory diagram schematically showing the configuration of the chassis dynamometer 1 of the present embodiment. [Figure 8] FIG. 8 is a flowchart showing the test contents of a vehicle including control operations by the turning model controller and the steering model controller shown in FIG. 7. [Figure 9] FIG. 9 is an explanatory diagram (Part 1) showing the processing contents of the turning determination process. [Figure 10] FIG. 10 is an explanatory diagram (Part 2) showing the processing contents of the turning determination process. [Figure 11] FIG. 11 is an explanatory diagram showing the processing contents of the steering turning radius calculation process and the turning command angle determination process.

MODE FOR CARRYING OUT THE INVENTION

[0017] <Embodiment> (Overall Configuration) FIG. 1 is a perspective view schematically showing the configuration of the chassis dynamometer 1 of the present embodiment after the vehicle 60 is placed thereon. In FIG. 1, an XYZ orthogonal coordinate system is shown.

[0018] As shown in FIG. 1, the four tires 6 of the vehicle 60 are placed on the roller pairs 20 of the four roller devices 2. Each roller device 2 has a roller pair 20 on which the tire 6 of the vehicle 60 is placed. Further, when a test on the vehicle 60 is performed, the vehicle 60 is fixed in a state of being placed on the roller pairs 20 of the four roller devices 2 by vehicle fixing means (not shown).

[0019] On the floor surface 50, a rectangular image simulator 62 with the X direction as the longitudinal direction and the Z direction as the lateral direction is provided in front of the vehicle 60 (+Y direction). The image simulator 62, which is a simulation auxiliary member, has a display function for displaying the entire scenery visually recognizable from the vehicle 60.

[0020] Vehicle 60 may also have external sensors (not shown). Possible external sensors include radar and LiDAR used in corner sensors, and side cameras (side electronic mirrors).

[0021] The chassis dynamometer 1 uses steering angle information of the vehicle 60's tires 6 and an image simulator 62 as needed, and receives information from the vehicle 60's external sensors as needed, to perform a driving test on the vehicle 60. The driving test includes a tire turning operation in which the vehicle 60's tires 6 turn, and a roller turning operation in which the roller pair 20 turns in conjunction with this tire turning operation.

[0022] (Regarding the terminology definitions for Vehicle 60) In this specification, the four tires 6 of a vehicle 60 are classified into Type 1 tire pairs and Type 2 tire pairs. In the embodiments described below, with respect to the four tires 6 of a vehicle 60, the front tire pair is defined as Type 1 tire pair and the rear tire pair is defined as Type 2 tire pair.

[0023] Therefore, a Type 1 tire pair includes a Type 1 left tire and a Type 1 right tire, with the front wheel tire 6L being the Type 1 left tire and the front wheel tire 6R being the Type 1 right tire.

[0024] Similarly, a Type 2 tire pair includes a Type 2 left tire and a Type 2 right tire, with the rear wheel tire 6L being the Type 2 left tire and the rear wheel tire 6R being the Type 2 right tire.

[0025] For the sake of explanation, the front tire 6L may be referred to as "front tire 6L," and the front tire 6R as "front tire 6R." Similarly, the rear tire 6L may be referred to as "rear tire 6L," and the rear tire 6R as "rear tire 6R."

[0026] The four rollers are classified into four types: the Type 1 left roller, which supports the Type 1 left front tire 6L; the Type 1 right roller, which supports the Type 1 right front tire 6R; the Type 2 left roller, which supports the Type 2 left rear tire 6L; and the Type 2 right roller, which supports the Type 2 right rear tire 6R. A Type 1 roller pair is formed by the Type 1 left roller and the Type 1 right roller, and a Type 2 roller pair is formed by the Type 2 left roller and the Type 2 right roller.

[0027] Figure 1 shows four roller pairs 20 as four rollers. For the sake of explanation, the four roller pairs 20 may be simply referred to as "four rollers" below. The roller rotation mechanism DM1, described later, performs a roller rotation process that rotates the first type roller pair (the first type left roller and the first type right roller) of the four rollers. The roller drive mechanism DM2, described later, performs a roller drive process that rotates all four rollers.

[0028] (Configuration of displacement sensor 7) Figure 2 is a schematic diagram illustrating the displacement sensor 7 and its surroundings in the chassis dynamometer 1 of this embodiment. The figure shows an XYZ Cartesian coordinate system. As will be described later, the displacement sensor 7 is a main component of the first embodiment of the steering angle detection mechanism.

[0029] The roller rotation mechanism DM1 has turntables 32L and 32R. The roller rotation mechanism DM1 takes a pair of rollers 20 (front roller 20F + rear roller 20B), which are first-type left rollers, as the object to be rotated to the left and performs a left-side roller rotation process to rotate the object to be rotated to the left along the roller rotation direction R2. The turntable 32L rotates along the roller rotation direction R2 during the left-side roller rotation operation.

[0030] Similarly, the roller rotation mechanism DM1 takes the pair of rollers 20 (front roller 20F + rear roller 20B), which are the first type right rollers, as the object to be rotated to the right, and performs a right-side roller rotation process to rotate the object to be rotated to the right along the roller rotation direction R2. The rotation platform 32R rotates along the roller rotation direction R2 during the right-side roller rotation operation.

[0031] Thus, the roller drive mechanism DM2 performs roller rotation processing, including the left-side roller rotation processing and the right-side roller rotation processing described above.

[0032] Figure 2 shows the front wheel tire 6L, which is the left tire of type 1, placed on the left roller of type 1, and the front wheel tire 6R, which is the right tire of type 1, placed on the right roller of type 1.

[0033] The left displacement sensor 7L detects the left tire steering angle, which is the angle (steering angle) of the tire 6L relative to the fixed reference direction (longitudinal direction; Y direction), using the distance measurement area 90 of the front tire 6L (described later) as the detection target, and obtains left steering angle information S7L. In other words, the left steering angle information S7L represents the left tire steering angle detected by the left displacement sensor 7L as an angular displacement amount. The tire angle detection range 37L indicates the detection range by the left displacement sensor 7L.

[0034] Similarly, the right-side displacement sensor 7R detects the distance measurement area 90 of the front tire 6R and obtains right steering angle information S7R by detecting the right tire steering angle, which is the angle of the front tire 6R with respect to the fixed reference direction. The right steering angle information S7R represents the right tire steering angle detected by the right-side displacement sensor 7R as an angular displacement amount. The tire angle detection range 37R indicates the detection range by the right-side displacement sensor 7R.

[0035] In this embodiment, the fixed reference direction of the tire 6 does not change due to the roller rotation operation. Thus, in this embodiment, a fixed reference direction is adopted as the reference direction for the tire cutting angle.

[0036] The left displacement sensor 7L is fixedly positioned in the external area of ​​the turntable 32L, and the right displacement sensor 7R is fixedly positioned in the external area of ​​the turntable 32R. In other words, the left displacement sensor 7L is positioned in a location that is not rotated when the left roller rotation process is performed by the roller rotation mechanism DM1, and therefore is not included in the objects that are rotated to the left. Similarly, the right displacement sensor 7R is positioned in a location that is not rotated when the right roller rotation process is performed by the roller rotation mechanism DM1, and therefore is not included in the objects that are rotated to the right.

[0037] Figure 3 is a schematic explanatory diagram showing the AA cross-section of Figure 2. The XYZ Cartesian coordinate system is shown in Figure 3. As shown in the figure, tire 6 (tire 6L) has a distance measurement area 90 at its bottom as the measurement target area, and multiple measurement points 9 are provided within the distance measurement area 90 along the linear direction (Y direction in Figure 3). The multiple measurement points 9 have structural features that can be recognized by the left displacement sensor 7L. Various shapes can be considered as structural features, such as protrusions.

[0038] The left displacement sensor 7L has a distance detection function that detects multiple (sensor-tire distance) measurements from the left displacement sensor 7L (detection point) to each of the multiple measurement points 9 to obtain distance information. Of course, the right displacement sensor 7R also has the same cross-sectional configuration and distance detection function as the left displacement sensor 7L, as shown in Figure 3.

[0039] Figure 4 is a schematic diagram illustrating the configuration of the roller rotation drive unit 3, which is the main part of the roller rotation mechanism DM1. The roller rotation drive unit 3 shown in this figure has a common structure to both the roller rotation drive unit 3L and the roller rotation drive unit 3R. Hereafter, the roller rotation drive unit 3L and the roller rotation drive unit 3R may be collectively referred to simply as "roller rotation drive unit 3".

[0040] The roller slewing drive unit 3 mainly includes a slewing structure 31 (roller device 2), a slewing bearing 34, a base 36, and a slewing motor 42 (42L, 42R). The slewing structure 31 includes a slewing platform 32 (32L, 32R) and a slewing bed 35, and is integrated with the roller device 2 which has a pair of rollers 20.

[0041] The slewing motor 42 is a geared motor with speed control. A gear is attached to the tip of the slewing motor 42 and engages with a gear (not shown) attached to the outer circumference of the base 36. Therefore, the rotation of the slewing motor 42 can cause the slewing bed 35 to rotate.

[0042] The slewing bearing 34 supports the slewing bed 35 so that it can rotate, and the slewing bed 35 is rotated by the power of the slewing motor 42 with the center of the slewing bearing 34 as the pivot point. As the slewing bed 35 rotates, the slewing structure 31 also rotates.

[0043] Thus, the roller swivel drive unit 3 has a swivel structure 31 that is swiveled by a swivel motor 42. When the swivel structure 31 is swiveled, the roller pair 20 integrated with the swivel structure 31 also swivels along the roller swivel direction R2.

[0044] Hereinafter, when referring to the left displacement sensor 7L and the right displacement sensor 7R collectively, they will simply be called "displacement sensor 7," and when referring to the left steering angle information S7L and the right steering angle information S7R collectively, they will simply be called "steering angle information S7."

[0045] Figure 5 is a schematic diagram illustrating the contents of the distance measurement area 90 (measurement target area) provided on the tire 6. As shown in the figure, eight measurement points 91 to 98 are provided as multiple measurement points 9 within the distance measurement area 90. Eight measurement points 91 to 98 are just one example of multiple measurement points, and of course, the number of measurement points is not limited to eight.

[0046] Figure 6 is a flowchart showing the method for acquiring steering angle information S7 using the displacement sensor 7. The acquisition of steering angle information S7 will be explained below with reference to Figures 5 and 6.

[0047] First, in step ST1, the measurement point coordinate calculation process is performed. The measurement point coordinate calculation process includes the following sub-steps ST1-1 and ST1-2.

[0048] Step ST1-1 is a sub-step in which the distance from the displacement sensor 7 to each of the measurement points 91 to 98 is obtained as the measured distance L91 to L98. The displacement sensor 7 detects the distance from the displacement sensor 7 to each of the measurement points 91 to 98 and obtains the measured distance L91 to L98. In this way, the displacement sensor 7 has a distance detection function that obtains multiple measured distances (measured distances L91 to L98) from the displacement sensor 7 to each of the multiple measurement points (measurement points 91 to 98).

[0049] Step ST1-2 is a sub-step that "obtains the coordinate positions of measurement points 91-98 on the horizontal plane (XY plane) from the measurement distance L91-L98 as measurement coordinates C91-C98."

[0050] In this way, by executing the measurement point coordinate calculation process (ST1) which includes partial steps ST1-1 and ST1-2, the measurement coordinates C91 to C98 of multiple measurement points, which are measurement points 91 to 98, can be obtained as multiple measurement coordinates.

[0051] Next, in step ST2, a regression line, which is an approximate straight line for the tire, is determined based on the measurement coordinates C91 to C98 obtained in step ST1, each indicating a coordinate position. This approximate straight line for the tire will be the straight line indicating the direction of tire 6.

[0052] Subsequently, in step ST3, the tire turning angle is obtained from the angle formed between the pre-prepared reference direction and the approximate straight line for the tire. In this embodiment, a fixed reference direction is used, which indicates the straight direction (Y direction), which is the longitudinal direction of the vehicle 60. Therefore, the tire turning angle obtained by the roller rotation drive unit 3L becomes the left tire turning angle, and the tire turning angle obtained by the roller rotation drive unit 3R becomes the right tire turning angle.

[0053] Then, in step ST4, the displacement sensor 7 outputs steering angle information S7, which indicates the tire cutting angle calculated in step ST3. In other words, the steering angle information S7 indicates the tire cutting angle as an angular displacement.

[0054] Thus, the chassis dynamometer 1 of this embodiment can directly determine the tire cutting angle, which is the angular displacement, by using a displacement sensor 7 with a distance detection function to detect a distance measurement area 90 (measurement target area) provided on the tire 6.

[0055] Therefore, the left displacement sensor 7L detects left steering angle information S7L, which is the angle of the front wheel tire 6L, which is the first-class left tire, relative to the reference direction, and the right displacement sensor 7R detects right steering angle information S7R, which is the angle of the front wheel tire 6R, which is the first-class right tire, relative to the reference direction, indicating the right tire steering angle.

[0056] (Control system for chassis dynamometer 1) Figure 7 is a schematic diagram illustrating the configuration of the chassis dynamometer 1 in this embodiment, focusing on the control system. As shown in the figure, the chassis dynamometer 1 mainly includes a controller 75 which serves as a dynamo control device, a left-side displacement sensor 7L, a right-side displacement sensor 7R, a handle angle sensor 5, a roller rotation mechanism DM1, and a roller drive mechanism DM2.

[0057] The roller turning mechanism DM1 mainly includes motor drive units 19L and 19R, a motor 42L for left front wheel turning, a motor 42R for right front wheel turning, and encoders 55L and 55R. The motor 42L for left front wheel turning is a component of the roller turning drive unit 3L shown in Figure 4, and the motor 42R for right front wheel turning is a component of the roller turning mechanism 3R.

[0058] The roller drive mechanism DM2 mainly includes motor drive units 26L, 26R, 27L, and 27R, a motor 58L for driving the left front roller, a motor 58R for driving the right front roller, a motor 68L for driving the left rear roller, and a motor 68R for driving the right rear roller, as well as encoders 59L, 59R, 69L, and 69R.

[0059] The controller 75 mainly includes a turning model controller 21, a steering model controller 22, a restoring force coefficient setting unit 77, a steering angle conversion table T1, and contacts P1 to P4.

[0060] Contacts P1 to P4 receive a switching signal SX. When the switching signal SX is "H", contacts P1 and P3 are enabled, and contacts P2 and P4 are disabled. Conversely, when the switching signal SX is "L", contacts P1 and P3 are disabled, and contacts P2 and P4 are enabled.

[0061] The first embodiment of the steering angle detection mechanism includes a left-side displacement sensor 7L and a right-side displacement sensor 7R.

[0062] The left-side displacement sensor 7L detects the distance measurement area 90 (measurement target area) of the first-type left tire, detects the left tire steering angle of the first-type left tire, and obtains left steering angle information S7L indicating the left tire steering angle.

[0063] The right-side displacement sensor 7R detects the distance measurement area 90 (measurement target area) of the first-type right tire, detects the right tire steering angle of the first-type right tire, and obtains right steering angle information S7R indicating the right tire steering angle.

[0064] When using the first embodiment of the steering angle detection mechanism, the switching signal SX becomes "L", and contacts P2 and P4 among contacts P1 to P4 are enabled. Therefore, the left steering angle information S7L is taken into the turning model controller 21 as left steering angle information S1L via contact P2, and the right steering angle information S7R is taken into the turning model controller 21 as right steering angle information S1R via contact P4.

[0065] A second embodiment of the steering angle detection mechanism includes a turning model controller 21, a steering angle conversion table T1, and a steering angle sensor 5. When the turning model controller 21 is adopted as the second embodiment of the steering angle detection mechanism, it performs the steering angle recognition process described later.

[0066] The steering wheel angle sensor 5 detects the steering wheel angle during steering operation of the vehicle 60 and obtains steering wheel angle information S5 indicating the detected steering wheel angle.

[0067] The steering angle conversion table T1 contains multiple types of angle pair information, which is information that shows multiple types of left tire turning angles and multiple types of right tire turning angles in a format corresponding to multiple types of steering angles. Each of the multiple types of left tire turning angles corresponds to the left tire steering angle, and each of the multiple types of right tire turning angles corresponds to the right tire steering angle. The steering angle conversion table T1 corresponds to, for example, the steering angle conversion table T1 disclosed in Japanese Patent Application Publication No. 2022-175289 (Figures 7 and 13).

[0068] The turning model controller 21 receives steering angle information S5 and performs steering angle recognition processing to obtain left steering angle information S1L and right steering angle information S1R from the steering angle conversion table T1 based on the steering angle information S5. The steering angle recognition processing is performed only when the second embodiment is adopted as the steering angle detection mechanism.

[0069] When using the second embodiment of the steering angle detection mechanism, the switching signal SX becomes "H", and contacts P1 and P3 among contacts P1 to P4 are enabled. Therefore, the turning model controller 21 can access the steering angle conversion table T1 via contacts P1 and P3.

[0070] The steering angle recognition process involves referring to the steering angle conversion table T1 to select the left tire turning angle and right tire turning angle from among several types of left tire turning angles and several types of right tire turning angles, which correspond to the steering angle indicated by the steering angle information S5. The process then acquires information indicating the selected left tire turning angle and right tire turning angle as left steering angle information S1L and right steering angle information S1R.

[0071] Upon execution of the steering angle recognition process described above, information indicating the left tire turning angle selected in the steering angle conversion table T1 is received by the steering model controller 22 via contact P1 as left steering angle information S1L. Similarly, upon execution of the steering angle recognition process, information indicating the right tire turning angle selected in the steering angle conversion table T1 is received by the steering model controller 22 via contact P3 as right steering angle information S1R.

[0072] Thus, by adopting either the first or second embodiment, the steering angle detection mechanism of this embodiment can detect left steering angle information S1L, which indicates the left tire turning angle, which is the angle of the first type left tire with respect to the reference direction (Y direction), and right steering angle information S1R, which indicates the right tire turning angle, which is the angle of the first type right tire with respect to the reference direction.

[0073] In the following explanation, we will use the left steering angle θl as the left tire turning angle indicated by the left steering angle information S1L, and the right steering angle θr as the right tire turning angle indicated by the right steering angle information S1R.

[0074] As described above, in the first embodiment of the steering angle detection mechanism, the left steering angle θl coincides with the left tire turning angle detected by the left displacement sensor 7L, and the right steering angle θr coincides with the right tire turning angle detected by the right displacement sensor 7R.

[0075] On the other hand, in the second embodiment of the steering angle detection mechanism, the left steering angle θl matches the left tire turning angle selected from the steering angle conversion table T1, and the right steering angle θr matches the right tire turning angle selected from the steering angle conversion table T1.

[0076] The chassis dynamometer 1 in this embodiment, as shown in Figure 7, is configured to selectively use the first and second modes of the steering angle detection mechanism, but any configuration that can use at least one of the first and second modes of the steering angle detection mechanism is acceptable.

[0077] The turning model controller 21 performs turning determination processing and turning command angle calculation processing based on the left steering angle information S1L and the right steering angle information S1R.

[0078] The turning determination process determines whether the vehicle 60 is in a steering turning state or a straight-ahead state, and the turning command angle calculation process calculates the left turning command angle θlv and the right turning command angle θrv that should be given to the roller turning mechanism DM1.

[0079] The turning command angle calculation process is executed such that the left turning command angle θlv is smaller than the left steering angle θl indicated by the left steering angle information S1L, and the right turning command angle θrv is smaller than the right steering angle θr indicated by the right steering angle information S1R.

[0080] The turning command angle calculation process includes the reference radius calculation process, steering turning radius calculation process, and turning command angle determination process, which will be described later.

[0081] The reference radius calculation process calculates the reference radius R0 for generating the restoring force, and the steering turning radius calculation process calculates the four steering turning radii, which are the steering turning radii for each of the four tires 6. The turning command angle determination process is the process of finally determining the left turning command angle θlv and the right turning command angle θrv.

[0082] The turning model controller 21 outputs the four steering turning radii obtained during the steering turning radius calculation process to the steering model controller 22.

[0083] The turning model controller 21 executes the turning command angle determination process included in the turning command angle calculation process to determine the left turning command angle θlv and the right turning command angle θrv. Subsequently, the turning model controller 21 outputs left steering angle instruction information SGL, which indicates the left turning command angle θlv, to the motor drive device 19L, and right steering angle instruction information SGR, which indicates the right turning command angle θrv, to the motor drive device 19R.

[0084] The motor drive device 19L within the roller turning mechanism DM1 outputs a drive control signal S19L to the front wheel left turning motor 42L, instructing it to perform left roller turning at the left turning command angle θlv indicated by the left steering angle instruction information SGL. The motor drive device 19L also receives encoder information S55L as a feedback signal from the encoder 55L. The encoder information S55L includes the measured value of the turning angle of the turning structure 31 in the roller turning drive unit 3L with respect to the reference direction.

[0085] The motor drive unit 19R and encoder 55R operate in the same manner as the motor drive unit 19L and encoder 55L, except that the motor being driven is the front wheel right-turn motor 42R.

[0086] Therefore, the roller rotation mechanism DM1 can perform a left-side roller rotation operation, in which the first-type left roller rotates along the roller rotation direction R2, by driving the rotation motor 42L with the motor drive device 19L.

[0087] Furthermore, the roller rotation mechanism DM1 can perform a right-side roller rotation process, which rotates the first-type right roller along the roller rotation direction R2, by driving the rotation motor 42R with a motor drive device 19R that receives encoder information S55R from the encoder 55R.

[0088] Meanwhile, the steering model controller 22 executes roller control processing. This roller control processing includes turning control processing and straight-line control processing for roller drive, which will be described later.

[0089] Figure 8 is a flowchart showing the test procedures for vehicle 60, including the control operations performed by the turning model controller 21 and steering model controller 22 shown in Figure 7. The following explanation will focus on the control operations performed by the turning model controller 21 and steering model controller 22, with reference to Figure 8.

[0090] First, in step ST10, the steering operation of the chassis dynamometer 1 is started, triggered by the reception of a steering operation command signal S70 from the external device 70 indicating the start of operation.

[0091] In step ST11, the controller 75, including the turning model controller 21 and the steering model controller 22, is set to a standby state.

[0092] Subsequently, in step ST12, steering operation of vehicle 60 is initiated. That is, vehicle 60 on the chassis dynamometer 1 enters a driving state.

[0093] Next, in step ST13, it is confirmed whether or not the displacement sensors 7 (left displacement sensor 7L + right displacement sensor 7R) are being used. If the displacement sensors 7 are being used (YES), the process proceeds to step ST14; if the displacement sensors 7 are not being used (NO), the process proceeds to step ST15.

[0094] In step ST14, which is executed when step ST13 is YES, the front left and right tire angle detection process is performed. That is, the first form of the steering angle detection mechanism (left displacement sensor 7L + right displacement sensor 7R) is adopted. Therefore, the switching signal SX of "L" enables contacts P2 and P4, and disables contacts P1 and P3 among contacts P1 to P4.

[0095] As a result, the left steering angle information S7L obtained from the left displacement sensor 7L is directly input to the turning model controller 21 as left steering angle information S1L, and the right steering angle information S7R obtained from the right displacement sensor 7R is directly input to the right steering angle information S1R.

[0096] Thus, when the first embodiment of the steering angle detection mechanism is adopted, the turning model controller 21 can acquire left steering angle information S7L and right steering angle information S7R as left steering angle information S1L and right steering angle information S1R.

[0097] Therefore, the left steering angle θl indicated by the left steering angle information S1L becomes the left tire turning angle indicated by the left steering angle information S7L, and the right steering angle θr indicated by the right steering angle information S1R becomes the right tire turning angle indicated by the left steering angle information S7L.

[0098] In step ST15, which is executed when step ST13 is NO, the steering angle detection process is performed. That is, the second form of the steering angle detection mechanism (turning model controller 21 + steering angle conversion table T1 + steering angle sensor 5) is adopted. Therefore, the switching signal SX of "H" enables contacts P1 and P3, and disables contacts P2 and P4 among contacts P1 to P4.

[0099] When step ST15 is executed, the turning model controller 21 becomes operational and performs the steering angle recognition process described above.

[0100] As a result, based on the steering angle information S5, the information indicating the left tire turning angle selected in the steering angle conversion table T1 is input into the turning model controller 21 as left steering angle information S1L, and the information indicating the right tire turning angle selected in the steering angle conversion table T1 is input into the turning model controller 21 as right steering angle information S1R.

[0101] Thus, when the second embodiment of the steering angle detection mechanism is adopted, the turning model controller 21 can acquire left steering angle information S1L and right steering angle information S1R by performing steering angle recognition processing.

[0102] Therefore, the left steering angle θl indicated by the left steering angle information S1L becomes the left tire turning angle selected in the steering angle conversion table T1. Similarly, the right steering angle θr indicated by the right steering angle information S1R becomes the right tire turning angle selected in the steering angle conversion table T1.

[0103] After step ST14 or step ST15 is executed, in step ST16, both the turning model controller 21 and the steering model controller 22 included in the controller 75 are set to an operating state. The processing group including steps ST16 to ST23 becomes the main control routine SM.

[0104] The rotation model controller 21 executes steps ST16 to ST19, ST22 and ST23 included in the main control routine SM, and step ST26 which is outside the main control routine SM.

[0105] The steering model controller 22 executes steps ST20 and ST21 included in the main control routine SM, and steps ST24 and ST25 outside of the main control routine SM.

[0106] In step ST16, the turning model controller 21 performs a turning determination process to determine whether the vehicle 60 is in a straight-ahead state or a steering-turn state.

[0107] The following describes the turning detection process in detail. Figures 9 and 10 are explanatory diagrams showing the processing details of the turning detection process. The XYZ Cartesian coordinate system is shown in both Figure 9 and Figure 10. The turning model controller 21 recognizes the left steering angle θl indicated by the left steering angle information S1L and the right steering angle θr indicated by the right steering angle information S1R. In Figure 9, the case where the front wheel tire pair 6,6 of the vehicle 60 is a Type 1 tire pair is shown.

[0108] Furthermore, the wheelbase L, front wheel tread Tf, and rear wheel tread Tb of vehicle 60 are pre-recognized. In addition, the maximum turning radius Rmax is pre-set. The maximum turning radius Rmax is set within a range of, for example, 200 to 1500 (m).

[0109] For example, the straight-ahead tire angle θmin for the turning detection process can be determined by the following equation (1), which is based on the maximum turning radius Rmax and the wheelbase L.

[0110]

number

[0111] The turning model controller 21 calculates the average steering angle θave using the following equation (2), which is based on the left steering angle θl and the right steering angle θr.

[0112]

number

[0113] Thus, the average steering angle θave is calculated based on the left steering angle θl, which is the left tire turning angle indicated by the left steering angle information S1L, and the right steering angle θr, which is the right tire turning angle indicated by the right steering angle information S1R.

[0114] The turning model controller 21 then determines that the vehicle is in a straight-ahead state if {|θave|≦θmin}, and that it is in a steering-turn state if {|θave|>θmin}.

[0115] Thus, in step ST16, the turning model controller 21 performs a turning determination process to determine whether the vehicle 60 is in a steering turning state or a straight-ahead state, based on the comparison result of the average steering angle θav and the straight-ahead determination tire angle θmin.

[0116] Subsequently, in step ST17, if the result of the turning determination process in step ST16 is a steering turning state (YES), the process proceeds to step ST18. If the result of the turning determination process in step ST16 is a straight-ahead state (NO), the process proceeds to steps ST21 and ST22, respectively.

[0117] If the answer to step ST17 is YES, the turning control process including steps ST18 to ST20 and step ST23 is executed. If the answer to step ST17 is NO, the straight-line control process including steps ST21 and ST22 is executed.

[0118] First, let's explain the control process during turning. In step ST18, the turning model controller 21 executes a reference radius calculation process to determine the reference radius R0 for generating the restoring force. The reference radius calculation process will be described in detail below.

[0119] First, the turning model controller 21 calculates the average turning radius Rave using the following equation (3), which is based on the average steering angle θave and the wheelbase L. The method for calculating the average turning radius Rave using equation (3) is the first calculation method. The first calculation method corresponds to Figure 9.

[0120]

number

[0121] As shown in Figure 9, the turning center C1 lies on the rear wheel reference line BL, at a distance of the average turning radius Rave in the +X direction from the rear wheel center point PB. The rear wheel reference line BL is a line connecting the centers of the rear tires 6(6L) and 6(6R) and extending along the X direction, and the rear wheel center point PB is the point on the rear wheel reference line BL that is the center of the rear wheels 6, 6.

[0122] Therefore, the first calculation method according to equation (3) is a process in which the distance from the turning center C1 to the virtual center tire placed on the rear wheel center position PB is calculated as the average turning radius Rave.

[0123] The second calculation method may be used instead of the first calculation method. The second calculation method calculates the average turning radius Rave using the following equation (4), which is based on the left steering angle θl, the right steering angle θr, and the wheelbase L. The second calculation method corresponds to Figure 10.

[0124]

number

[0125] As shown in FIG. 10, a left turning center C1L for the left steering angle θl and a right turning center C1R for the right steering angle θr are set individually. The left turning center C1L is located on the -X direction side compared to the right turning center C1R.

[0126] Therefore, the second calculation method according to Equation (4) is a process of calculating the average value of the turning radius (L / tan(θl)) for the front left tire 6L and the turning radius (L / tan(θr)) for the front right tire 6R as the average turning radius Rave.

[0127] Also, a virtual turning center C1V where the average turning radius Rave exists on the +X direction side from the rear wheel center position PB exists on the +X direction side from the left turning center C1L and on the -X direction side from the right turning center C1R. This virtual turning center C1V does not necessarily coincide with the turning center C1 shown in FIG. 9.

[0128] Next, in sub-step ST18p included in step ST18, the turning model controller 21 acquires a restoring force parameter K from a restoring force coefficient setting unit 77 which is a restoring force integration coefficient imparting unit.

[0129] Therefore, by acquiring the restoring force parameter K from the restoring force coefficient setting unit 77, the turning model controller 21 can recognize the restoring force integration coefficient (K / 100).

[0130] When sub-step ST18p ends, the turning model controller 21 obtains a reference radius R0 for generating a restoring force according to the following Equation (5) based on the average turning radius Rave.

[0131]

Equation

[0132] [ In Equation (5), (K / 100) is the restoring force integration coefficient. K is a fixed value desirably set to about 120 in the range of {100 < K ≤ 160}. Therefore, the restoring force integration coefficient (K / 100) exceeds "1".

[0133] The control pivot center C0 is located on the rear wheel reference line BL, at a distance of +X from the rear wheel center position PB, with a reference radius R0 (>Rave) for generating the restoring force.

[0134] Thus, the turning model controller 21 calculates the average turning radius Rave based on the left steering angle θl indicated by the left steering angle information S1L and the right steering angle θr indicated by the right steering angle information S1R, and then performs a reference radius calculation process to calculate the reference radius R0 for generating the restoring force by integrating the average turning radius Rave with the restoring force integration coefficient (K / 100). At this time, the restoring force integration coefficient (K / 100) is set to a value greater than "1".

[0135] Figure 11 is an explanatory diagram showing the processing steps for calculating the steering radius and determining the turning command angle. The XYZ Cartesian coordinate system is shown in Figure 11.

[0136] After step 18 is executed, in step ST19, the turning model controller 21 performs a steering turning radius calculation process that calculates the steering turning radius of each of the four tires based on the reference radius R0 for generating the restoring force. The steering turning radius (m) from the control turning center C0 of each of the four tires 6 becomes the steering turning radius of each of the four tires.

[0137] The four steering turning radii include the rear wheel left radius Rbl, the rear wheel right radius Rbr, the front wheel left radius Rfl, and the front wheel right radius Rfr. The operating entity in step ST19 is the turning model controller 21.

[0138] First, the left rear wheel radius Rbl is determined by equation (6), which is based on the reference radius R0 for generating the restoring force and the rear wheel tread Tb.

[0139]

number

[0140] Next, the right rear wheel radius Rbr can be determined by the following equation (7), which is based on the left rear wheel radius Rbl and the rear wheel tread Tb obtained in equation (6).

[0141]

number

[0142] Subsequently, the left front wheel radius Rfl can be determined by the following equation (8), which is based on the left rear wheel radius Rbl obtained by equation (6), the wheelbase L, the front wheel tread Tf, and the rear wheel tread Tb.

[0143]

number

[0144] Next, the right rear wheel radius Rfr can be calculated using the following equation (9), which is based on the right rear wheel radius Rbr obtained in equation (7), the wheelbase L, the front wheel tread Tf, and the rear wheel tread Tb.

[0145]

number

[0146] In this manner, the turning model controller 21 performs a steering turning radius calculation process to calculate four steering turning radii (Rfl, Rfr, Rbl, Rbr), which are the steering turning radii of each of the four tires 6, based on the reference radius R0 for generating the restoring force.

[0147] In other words, in step ST19, the turning model controller 21 performs a steering turning radius calculation process to determine the four steering turning radii from the control turning center C0 for each of the four tires 6 by using equations (6) to (9). The four steering turning radii (Rbl, Rbr, Rfl, and Rfr) determined by the turning model controller 21 are then assigned to the steering model controller 22.

[0148] After step ST19 is executed, the first processing group ST20, ST24, and ST25, and the second processing group ST23 and ST26 are executed. Both the first and second processing groups are turning control processing. The first processing group is turning control processing for roller drive, and the second processing group is turning control processing for turning.

[0149] The first processing group is primarily driven by the steering model controller 22, and the second processing group is primarily driven by the turning model controller 21. Therefore, the first and second processing groups can be executed in parallel.

[0150] First, let's explain the first processing group. In step ST20, the steering model controller 22 calculates the target control speed (km / h) for each of the four rollers based on the four steering turning radii (Rbl, Rbr, Rfl, and Rfr) obtained in step ST19. The four target control speeds include the front left target speed Vfl, the front right target speed Vfr, the rear left target speed Vbl, and the rear right target speed Vbr.

[0151] During step ST19, the rotational speed of each of the four rollers is measured. The four roller rotational speeds (km / h) include the front left wheel speed Mfl, the front right wheel speed Mfr, the rear left wheel speed Mbl, and the rear right wheel speed Mbr.

[0152] As shown in Figure 7, encoder information S59L of the motor 58L for driving the front left roller is fed back from the encoder 59L to the motor drive device 26L. Based on the encoder information S59L, the motor drive device 26L feeds back front left motor speed information PV1L, which indicates the front left measuring speed Mfl of the first type left roller, to the steering model controller 22. Therefore, the steering model controller 22 can recognize the rotational speed (Mfl) of the first type left roller by referring to the front left motor speed information PV1L.

[0153] Encoder information S59R for the motor 58R that drives the front right roller is fed back from encoder 59R to motor drive device 26R. Based on the encoder information S59R, motor drive device 26R feeds back front right motor speed information PV1R, which indicates the front right measuring speed Mfr, to steering model controller 22. Therefore, steering model controller 22 can recognize the rotational speed (Mfr) of the first type right roller by referring to the front right motor speed information PV1R.

[0154] Encoder information S69L for the rear left roller drive motor 68L is fed back from encoder 69L to motor drive device 27L. Based on the encoder information S69L, motor drive device 27L feeds back rear left motor speed information PV2L, which indicates the rear left measurement speed Mbl of the second type left roller, to steering model controller 22. Therefore, steering model controller 22 can recognize the rotational speed (Mbl) of the second type left roller by referring to the rear left motor speed information PV2L.

[0155] Encoder information S69R for the rear right roller drive motor 68R is fed back from encoder 69R to motor drive device 27R. Based on the encoder information S69R, motor drive device 27R feeds back rear right motor speed information PV2R, which indicates the rear right measurement speed Mbr of the second type right roller, to steering model controller 22. Therefore, steering model controller 22 can recognize the rotational speed (Mbr) of the second type right roller by referring to the rear right motor speed information PV2R.

[0156] Subsequently, the steering model controller 22 calculates the reference speed Vd (km / h) and the reference turning radius Rd (m). The reference speed Vd is obtained from the following equation (10) based on the measured roller rotation speeds (Mfl, Mfr, Mbl, Mbr), and the reference turning radius Rd is obtained from the following equation (11) based on the four steering turning radii (Rbl, Rbr, Rfl, and Rfr).

[0157]

number

[0158]

number

[0159] Next, the steering model controller 22 calculates the target control speed (km / h) for each of the four rollers based on the reference speed Vd and the reference turning radius Rd. The four target control speeds include the front left target speed Vfl, the front right target speed Vfr, the rear left target speed Vbl, and the rear right target speed Vbr.

[0160] The front left target speed Vfl is calculated by the following formula (12) based on the front left radius Rfl, reference speed Vd, and reference turning radius Rd, and the front right target speed Vfr is calculated by the following formula (13) based on the front right radius Rfr, reference speed Vd, and reference turning radius Rd.

[0161]

number

[0162]

number

[0163] Similarly, the target speed Vbl for the left rear wheel is calculated by the following formula (14) based on the left rear wheel radius Rbl, the reference speed Vd, and the reference turning radius Rd, and the target speed Vbr for the right rear wheel is calculated by the following formula (15) based on the right rear wheel radius Rbr, the reference speed Vd, and the reference turning radius Rd.

[0164]

number

[0165]

number

[0166] In this way, the steering model controller 22 calculates four control target speeds (km / h) by executing step ST20.

[0167] In step ST24, which is performed after step ST20, the steering model controller 22 distributes motor torque to rotate the four rollers at four different control target speeds (km / h).

[0168] Subsequently, in step ST25, the steering model controller 22 executes the operation process for the roller drive motor. That is, the steering model controller 22 outputs four roller drive commands in accordance with the motor torque distribution details from step ST24.

[0169] The four roller drive commands include the front left motor torque command SL1L, the front right motor torque command SL1R, the rear left motor torque command SL2L, and the rear right motor torque command SL2R.

[0170] The steering model controller 22 outputs a front left motor torque command SL1L to the motor drive device 26L. The motor drive device 26L drives the front left roller drive motor 58L to achieve the front left target speed Vfl in accordance with the front left motor torque command SL1L.

[0171] As a result, the first type left roller is rotated by the front left roller drive motor 58L at the front left target speed Vfl. During the drive process of the front left roller drive motor 58L by the motor drive device 26L, encoder information S59L from the encoder 59L is fed back to the motor drive device 26L.

[0172] The steering model controller 22 outputs a front right motor torque command SL1R to the motor drive device 26R. The motor drive device 26R drives the front right roller drive motor 58R to achieve the front right target speed Vfr in accordance with the front right motor torque command SL1R.

[0173] As a result, the first type right roller is rotated at the front right target speed Vfr by the front right roller drive motor 58R. During the drive process of the front right roller drive motor 58R by the motor drive device 26R, encoder information S59R from the encoder 59R is fed back to the motor drive device 26R.

[0174] The steering model controller 22 outputs a rear left motor torque command SL2L to the motor drive device 27L. The motor drive device 27L drives the rear left roller drive motor 68L to achieve the rear left target speed Vbl according to the rear left motor torque command SL2L.

[0175] As a result, the second left roller is rotated at the target rear left speed Vbl by the rear left roller drive motor 68L. During the drive process of the rear left roller drive motor 68L by the motor drive device 27L, encoder information S69L from the encoder 69L is fed back to the motor drive device 27L.

[0176] The steering model controller 22 outputs a rear right motor torque command SL2R to the motor drive device 27R. The motor drive device 27R drives the rear right roller drive motor 68R to achieve the rear right target speed Vbr according to the rear right motor torque command SL2R.

[0177] As a result, the second right roller is rotated at the target rear right speed Vbr by the rear right roller drive motor 68R. During the drive process of the rear right roller drive motor 68R by the motor drive device 27R, encoder information S69R from encoder 69R is fed back to the motor drive device 27R.

[0178] In this way, the steering model controller 22 performs roller control processing that ultimately outputs four roller drive commands (SL1L, SL1R, SL2L, and SL2R) to the roller drive mechanism DM2.

[0179] Furthermore, as a variation of step ST20, it is also conceivable that the contents of equations (10) and (11) for calculating the reference speed Vd and reference turning radius Rd may be appropriately modified according to the specifications of the vehicle 60.

[0180] Next, the second processing group will be described. After step ST19 is executed, in step ST23, the turning model controller 21 performs the turning command angle determination process. Prior to step ST23, the steering turning radius calculation process in step ST19 is performed, and the four steering turning radii, which are the steering turning radii of each of the four tires 6, have already been calculated. The four steering turning radii include the front wheel left radius Rfl, which is the first type left turning radius, and the front wheel right radius Rfr, which is the first type right turning radius.

[0181] The turning command angle determination process involves determining the left turning command angle θlv using the following equation (16) based on the left radius Rfl of the front wheel and the wheelbase L, and determining the left turning command angle θlv using the following equation (17) based on the right radius Rfr of the front wheel and the wheelbase L.

[0182]

number

[0183]

number

[0184] The turning model controller 21 performs a reference radius calculation process in step ST18 of Figure 8. The reference radius calculation process involves first determining the average turning radius Rave based on the left steering angle θl and the right steering angle θr or the average steering angle θave, and then calculating the reference radius R0 for generating the restoring force based on the average turning radius Rave.

[0185] Furthermore, since the average steering angle θave can be obtained by applying equation (2) to the left steering angle θl and the right steering angle θr, the reference radius calculation process involves calculating the reference radius R0 for generating the restoring force based on the left steering angle θl and the right steering angle θr.

[0186] The turning model controller 21 performs the steering turning radius calculation process in step ST19 of Figure 8. The steering turning radius calculation process calculates four steering turning radii (Rbl, Rbr, Rfl, and Rfr) using the reference radius R0 for generating the restoring force.

[0187] Of the four steering turning radii, the front left radius Rfl, corresponding to the front tire 6L which is a Class 1 left tire, is defined as the Class 1 left turning radius, and the front right radius Rfr, corresponding to the front tire 6R which is a Class 1 right tire, is defined as the Class 1 right turning radius.

[0188] Furthermore, the turning model controller 21 performs turning command angle determination processing in step ST23 of Figure 8. The turning command angle determination processing determines the left turning command angle θlv based on the front wheel left radius Rfl, which is the first type left turning radius, and determines the right turning command angle θrv based on the front wheel right radius Rfr, which is the first type right turning radius.

[0189] Therefore, the turning command angle calculation process, which includes the calculation of the reference radius, the calculation of the steering turning radius, and the determination of the turning command angle, is a process that calculates the left turning command angle θlv and the right turning command angle θrv based on the left steering angle θl and the right steering angle θr.

[0190] Subsequently, in step ST26, the turning model controller 21 performs motor operation processing for turning the front wheels. Specifically, the turning model controller 21 outputs left steering angle instruction information SGL, which indicates a left turning command angle θlv, to the motor drive device 19L, and right steering angle instruction information SGR, which indicates a right turning command angle θrv, to the motor drive device 19R.

[0191] The motor drive device 19L controls the front wheel left-turn motor 42L by outputting a drive control signal S19L, thereby causing the roller turning drive unit 3L to perform a roller turning operation. The roller turning operation by the roller turning drive unit 3L is performed so that the turning structure 31, including the first left roller, turns at the left-turn command angle θlv indicated by the left steering angle instruction information SGL. During the drive process of the front wheel left-turn motor 42L by the motor drive device 19L, encoder information S55L from the encoder 55L is fed back to the motor drive device 19L.

[0192] The motor drive device 19R controls the motor by outputting a drive control signal S19R to the front wheel right-turn motor 42R, thereby causing the roller turning drive unit 3R to perform a roller turning operation. The roller turning operation by the roller turning drive unit 3R is performed so that the turning structure 31 that presses on the first type right roller turns at the right-turn command angle θrv instructed by the right steering angle instruction information SGR. During the drive process of the front wheel right-turn motor 42R by the motor drive device 19R, encoder information S55R from the encoder 55R is fed back to the motor drive device 19R.

[0193] Based on encoder information S55L, the motor drive device 19L feeds back left rotation angle information PGL, which indicates the rotation angle of the rotation structure 31 of the roller rotation drive unit 3L with respect to the reference direction (Y direction), to the rotation model controller 21. Therefore, the rotation model controller 21 can recognize the rotation angle of the rotation structure 31 of the roller rotation drive unit 3L by referring to the left rotation angle information PGL.

[0194] Similarly, the motor drive device 19R feeds back right-turn angle information PGR, which indicates the turn angle of the swivel structure 31 of the roller swivel drive unit 3R with respect to the reference direction, to the swivel model controller 21 based on the encoder information S55R. Therefore, the swivel model controller 21 can recognize the turn angle of the swivel structure 31 of the roller swivel mechanism 3R by referring to the right-turn angle information PGR.

[0195] If the answer in step ST17 is NO, the third processing group in steps ST21, ST24, and ST25, and the fourth processing group in steps ST22 and ST26 are executed. Both the third and fourth processing groups are straight-line control processing. The third processing group is straight-line control processing for roller drive, and the fourth processing group is straight-line control processing for turning.

[0196] The third processing group is primarily driven by the steering model controller 22, and the fourth processing group is primarily driven by the turning model controller 21. Therefore, the third and fourth processing groups can be executed in parallel.

[0197] First, let's explain the third processing group. In step ST21, the steering model controller 22 sets the control target speed (km / h) of each of the four rollers to the same common speed. That is, the front left target speed Vfl, the front right target speed Vfr, the rear left target speed Vbl, and the rear right target speed Vbr are set to the same common speed.

[0198] In step ST24, which is performed after step ST21, the steering model controller 22 distributes motor torque to rotate the four rollers at four target control speeds.

[0199] Subsequently, in step ST25, the steering model controller 22 executes the operation process for the roller drive motor. That is, the steering model controller 22 outputs four roller drive commands in accordance with the motor torque distribution details in step ST24.

[0200] In this way, the steering model controller 22 executes a straight-line control process for roller driving as a roller control process that ultimately outputs four roller drive commands (SL1L, SL1R, SL2L, and SL2R) to the roller drive mechanism DM2.

[0201] Next, the fourth processing group will be described. In step ST22, the rotation model controller 21 executes rotation command angle fixing processing. Rotation command angle fixing processing is the process of setting the left rotation command angle θlv and the right rotation command angle θrv to the same common angle, which is, for example, "0°" which is aligned with the fixed reference direction.

[0202] Subsequently, in step ST26, the turning model controller 21 performs motor operation processing for front wheel turning. That is, the turning model controller 21 outputs left steering angle instruction information SGL, which indicates the left turning command angle θlv, to the motor drive device 19L, and right steering angle instruction information SGR, which indicates the right turning command angle θrv, to the motor drive device 19R. At this time, the left turning command angle θlv and the right turning command angle θrv are the same common angle as described above.

[0203] As described above, when the turning model controller 21 determines that the vehicle 60 is in a steering turning state, it executes a turning command angle calculation process as a turning control process for turning. The turning command angle calculation process includes a reference radius calculation process (step ST18), a steering turning radius calculation process (step ST19), and a turning command angle determination process (step ST23).

[0204] On the other hand, when the turning model controller 21 determines that the vehicle 60 is in a straight-ahead state, it executes a straight-ahead control process for turning, including steps ST22 and ST26.

[0205] The roller rotation mechanism DM1 performs a roller rotation process that rotates the first-type left roller and the first-type right roller based on the left steering angle instruction information SGL corresponding to the first-type left roller and the right steering angle instruction information SGR corresponding to the first-type right roller.

[0206] As described above, the steering model controller 22 executes a turning control process for roller drive, including steps ST20, ST24, and ST25, as a roller control process when it is determined that the vehicle 60 is in a steering turning state.

[0207] Meanwhile, the steering model controller 22, when it determines that the vehicle 60 is in a straight-ahead state, executes a straight-ahead control process for roller driving, including steps ST21, ST24, and ST25, as a roller control process during straight-ahead determination. Thus, the roller control process executed under the control of the steering model controller 22 includes a turning control process for roller driving and a straight-ahead control process for roller driving.

[0208] The roller drive mechanism DM2 performs roller drive processing to rotate the four corresponding rollers based on four roller drive commands (SL1L, SL1R, SL2L, and SL2R) corresponding to the four rollers.

[0209] (modified version) In this embodiment, the chassis dynamometer 1 is equipped with a restoring force coefficient setting unit 77 within the controller 75, and the restoring force parameter K is provided to the swing model controller 21 from the restoring force coefficient setting unit 77. Alternatively, a modification can be considered in which the restoring force coefficient setting unit 77 is omitted and the swing model controller 21 is equipped with a function to calculate the restoring force parameter K.

[0210] In the modified chassis dynamometer 1, the swing model controller 21 performs the following first and second alternative steps instead of substep ST18p in step ST18 shown in Figure 8. The first and second alternative steps are processes for calculating the restoring force integration coefficient. That is, by calculating the restoring force parameter K, the restoring force integration coefficient (=K / 100) can be obtained.

[0211] First, let's explain the first alternative step. The first alternative step, which is the process for calculating the restoring force integration coefficient, is the step of calculating the restoring force parameter K using the following equation (18) based on the maximum turning radius Rmax and the average turning radius Rave.

[0212]

number

[0213] The second alternative step, which involves calculating the restoring force integration coefficient, is the step of calculating the restoring force parameter K using the following equation (19) based on the average steering angle θave. Note that the angle difference Δθ in equation (19) is a predetermined angle difference (fixed value).

[0214]

number

[0215] If the second alternative step is adopted, the reference radius R0 for generating the restoring force can also be calculated using the following equation (20), which is derived from equations (19) and (2).

[0216]

number

[0217] Thus, in the modified chassis dynamometer 1, the turning model controller 21 can perform a restoring force integration coefficient calculation process (first or second alternative step) that calculates the restoring force integration coefficient (=K / 100) using a calculation formula based on the average turning radius Rave (equation (18)) or a calculation formula based on the average steering angle θave (equation (19)).

[0218] (effect) The chassis dynamometer 1, an embodiment of the present disclosure, includes as its main components a controller 75, a left-side displacement sensor 7L, a right-side displacement sensor 7R, a handle angle sensor 5, a roller rotation mechanism DM1, and a roller drive mechanism DM2, as shown in Figure 7.

[0219] In this embodiment, the controller 75 in the chassis dynamometer 1 has a turning model controller 21. The turning model controller 21 can accurately determine whether the vehicle 60 is in a steering turning state or a straight-ahead state by performing a turning determination process based on the comparison result of the average steering angle θave and the straight-ahead determination tire angle θmin.

[0220] In the chassis dynamometer 1 of this embodiment, the turning model controller 21 performs a turning command angle calculation process to calculate the left turning command angle θlv and the right turning command angle θrv.

[0221] The left turn command angle θlv is set to be smaller than the left steering angle θl, which is the left tire turning angle indicated by the left steering angle information S1L, and the right turn command angle θrv is set to be smaller than the right steering angle θr, which is the right tire turning angle indicated by the right steering angle information S1R. In other words, the left turn command angle θlv and the right turn command angle θrv are angles closer to the Y direction, which is the reference direction, compared to the left steering angle θl and the right steering angle θr.

[0222] Therefore, the chassis dynamometer 1 of this embodiment 1 can perform a driving test of the vehicle 60 by generating a steering restoring force, which is the restoring force generated when the steering wheel of the tire 6 is turned, when the vehicle 60 is in a steering turn state.

[0223] As a result, the chassis dynamometer 1 of this embodiment can accurately perform driving tests on the vehicle 60 when the vehicle 60 is in a steering / turning state.

[0224] In this embodiment, the turning model controller 21 in the chassis dynamometer 1 performs a turning command angle fixing process that fixes the left turning command angle θlv and the right turning command angle θrv to the same common angle when determining whether the vehicle is moving straight.

[0225] As a result, the chassis dynamometer 1 of this embodiment can accurately perform driving tests on the vehicle 60 when the vehicle is traveling in a straight line.

[0226] In this embodiment, the roller rotation mechanism DM1 in the chassis dynamometer 1 performs a roller rotation process that rotates the first type left roller and the first type right roller based on the left steering angle instruction information SGL and the right steering angle instruction information SGR.

[0227] The left steering angle instruction information SGL indicates the left turn command angle θlv, which is calculated based on the front wheel left radius Rfl, which is the first type left turn radius. The right steering angle instruction information SGR indicates the right turn command angle θrv, which is calculated based on the front wheel right radius Rfr, which is the first type right turn radius.

[0228] The left turn command angle θlv is calculated based on the front wheel left radius Rfl, which is calculated based on the reference radius R0 for generating the restoring force, and the reference radius R0 for generating the restoring force is set to be longer than the average turning radius Rave. Therefore, the left turn command angle θlv will be a smaller angle than the left steering angle θl indicated by the left steering angle information S1L.

[0229] Similarly, the right turn command angle θrv is calculated based on the front wheel right radius Rfr, and the front wheel right radius Rfr is calculated based on the reference radius R0 for generating the restoring force. Therefore, the right turn command angle θrv is smaller than the right steering angle θr indicated by the right steering angle information S1R.

[0230] Therefore, the chassis dynamometer 1 of this embodiment can perform roller turning processing so that a steering wheel restoring force is generated when the vehicle 60 is in a steering turning state.

[0231] In this embodiment, the controller 75 in the chassis dynamometer 1 is equipped with a restoring force coefficient setting unit 77 which serves as a restoring force integration coefficient setting unit. Therefore, the reference radius R0 for generating the restoring force can be calculated using the restoring force parameter K without having to calculate the restoring force integration coefficient (=K / 100) within the turning model controller 21.

[0232] In the modified chassis dynamometer 1 of this embodiment, the swing model controller 21 can obtain the restoring force integration coefficient (100 / K) itself by performing a restoring force integration coefficient calculation process. The restoring force integration coefficient calculation process is a first alternative step using equation (18) or a second alternative step using equation (19), replacing the substep ST18p shown in Figure 8.

[0233] In this embodiment, the roller drive mechanism DM2 of the chassis dynamometer 1 performs roller drive processing based on four roller drive commands (SL1L, SL1R, SL2L, and SL2R) output from the steering model controller 22.

[0234] Therefore, the chassis dynamometer 1 of this embodiment can accurately rotate the four rollers in accordance with the driving conditions of the vehicle 60.

[0235] In this embodiment, the steering model controller 22 in the chassis dynamometer 1 can output four roller drive commands to accurately rotate the four rollers in accordance with the steering and turning state of the vehicle 60 by executing turning control processing for roller drive, including steps ST20, ST24, and ST25.

[0236] In this embodiment, the steering model controller 22 in the chassis dynamometer 1 executes straight-line control processing for roller drive, including steps ST21, ST24, and ST25, so that the vehicle 60 can adapt to the straight-line state and output four roller drive commands for accurately rotating the four rollers with relative ease.

[0237] In this embodiment, the left displacement sensor 7L in the chassis dynamometer 1 detects the distance measurement area 90 provided on the front tire 6L, which is the first type left tire, and can directly detect the left tire steering angle with high accuracy. Similarly, the right displacement sensor 7R detects the distance measurement area 90 provided on the front tire 6R, which is the first type right tire, and can directly detect the right tire steering angle with high accuracy.

[0238] As a result, the chassis dynamometer 1 of this embodiment can perform driving tests of the vehicle 60 with greater accuracy, even when the vehicle 60 is in a steering / turning state.

[0239] The turning model controller 21 in the chassis dynamometer 1 of this disclosure can recognize left steering angle information S1L and right steering angle information S1R, which indirectly determine accurate left tire turning angles and right tire turning angles, by referring to the steering angle conversion table T1 and performing the steering angle recognition process described above, even when disturbance noise such as tire bulging occurs.

[0240] <Other> In this embodiment, the first tire pair is the front wheel pair and the second tire pair is the rear wheel pair. However, it is also possible to use a modified configuration in which the first tire pair is the rear wheel pair and the second tire pair is the front wheel pair, with the left steering angle θl and right steering angle θr being detected as the rear wheel pair, and the roller rotation drive unit 3 and displacement sensor 7 being located on the rear wheel side.

[0241] Furthermore, in the embodiment described above, a pair of rollers 20 with a twin-roller configuration was shown as the "roller" on which the tire 6 of the vehicle 60 is placed, but a single roller with a single-roller configuration may be used instead of the pair of rollers 20.

[0242] Although this disclosure has been described in detail, the above description is illustrative in all respects and the disclosure is not limited thereto. It is understood that countless variations not illustrated may be conceivable without falling outside the scope of this disclosure. [Explanation of symbols]

[0243] 1. Chassis Dynamometer 3,3L,3R Roller Swivel Drive Unit 5. Handle angle sensor 6, 6L, 6R tires 7. Displacement Sensor 7L Left side displacement sensor 7R Right-side displacement sensor 19L, 19R, 26L, 26R, 27L, 27R Motor Drive Device 21. Swivel Model Controller 22 Steering Model Controller 42L Front wheel left turn motor 42R Front wheel right turn motor 55L, 55R, 59L, 59R, 69L, 69R encoders 58L Front left roller drive motor 58R Front wheel right roller drive motor 60 vehicles 68L Rear left roller drive motor 68R Rear wheel right roller drive motor 75 Controllers 77 Restoring force coefficient setting section DM1 Roller Swivel Mechanism DM2 Roller Drive Mechanism T1 Steering Angle Conversion Table

Claims

1. A chassis dynamometer having four rollers on which the four tires of a vehicle are placed, The four tires include a front tire pair and a rear tire pair, where one of the front tire pair and the rear tire pair is defined as a Type 1 tire pair and the other as a Type 2 tire pair. The aforementioned pair of first-type tires includes a first-type left tire and a first-type right tire, which are arranged on the left and right sides, The aforementioned pair of Type 2 tires includes a Type 2 left tire and a Type 2 right tire, which are arranged on the left and right sides, The four rollers include a first-type left roller on which the first-type left tire is mounted, a first-type right roller on which the first-type right tire is mounted, a second-type left roller on which the second-type left tire is mounted, and a second-type right roller on which the second-type right tire is mounted. The chassis dynamometer is A steering angle detection mechanism that detects left steering angle information indicating the left tire steering angle, which is the angle of the first type left tire with respect to the reference direction, and right steering angle information indicating the right tire steering angle, which is the angle of the first type right tire with respect to the reference direction, The system includes a turning model controller that performs a turning determination process to determine whether the vehicle's driving state is a turning state or a straight-ahead state, based on a comparison result between the average steering angle and the straight-ahead determination tire angle. The average steering angle is calculated based on the left tire turning angle indicated by the left steering angle information and the right tire turning angle indicated by the right steering angle information. The turning model controller executes a turning command angle calculation process when it is determined by the turning determination process that the vehicle's driving state is the steering turning state. The aforementioned turning command angle calculation process is a process that calculates the left turning command angle based on the left steering angle information and calculates the right turning command angle based on the right steering angle information. The left turn command angle is smaller than the left tire turning angle indicated by the left steering angle information, and the right turn command angle is smaller than the right tire turning angle indicated by the right steering angle information. The chassis dynamometer is The roller rotation mechanism further comprises a roller rotation mechanism that performs a roller rotation process that rotates the first type left roller based on the left rotation command angle and rotates the first type right roller based on the right rotation command angle. Chassis dynamometer.

2. A chassis dynamometer according to claim 1, The turning model controller executes a turning command angle fixing process when it is determined by the turning determination process that the vehicle's driving state is the straight-ahead state. The aforementioned rotation command angle fixing process is a process that fixes the left rotation command angle and the right rotation command angle to the same common angle. Chassis dynamometer.

3. A chassis dynamometer according to claim 1, The aforementioned turning command angle calculation process includes a reference radius calculation process and a steering turning radius calculation process. The aforementioned reference radius calculation process calculates the average turning radius based on the left tire turning angle indicated by the left steering angle information and the right tire turning angle indicated by the right steering angle information, and then calculates the reference radius for generating the restoring force by multiplying the average turning radius by the restoring force integration coefficient, wherein the restoring force integration coefficient is set to a value greater than "1". The steering turning radius calculation process is a process that calculates four steering turning radii, which are the steering turning radii of each of the four tires, based on the reference radius for generating the restoring force. Of the four steering turning radii mentioned above, the steering turning radius corresponding to the first type left tire is defined as the first type left turning radius, and the steering turning radius corresponding to the first type right tire is defined as the first type right turning radius. The aforementioned turning command angle calculation process further includes a turning command angle determination process, The aforementioned turning command angle determination process is a process that determines the left turning command angle based on the first type left turning radius and determines the right turning command angle based on the first type right turning radius. Chassis dynamometer.

4. A chassis dynamometer according to claim 3, The chassis dynamometer is The system further includes a unit for assigning the restoring force integration coefficient to the turning model controller, Chassis dynamometer.

5. A chassis dynamometer according to claim 3, The turning model controller further performs a restoring force integration coefficient calculation process that calculates the restoring force integration coefficient using a calculation formula based on the average turning radius or the average steering angle. Chassis dynamometer.

6. A chassis dynamometer according to claim 4, A steering model controller that performs roller control processing that outputs four roller drive commands corresponding to the four rollers based on the four steering turning radii, The system further comprises a roller drive mechanism that performs a roller drive process to rotate the four rollers based on the four roller drive commands. Chassis dynamometer.

7. A chassis dynamometer according to claim 6, The steering model controller executes a turning control process for roller drive when it is determined by the turning determination process that the vehicle's driving state is the steering turning state. The roller control process includes the rotation control process, The aforementioned turning control process is: (a) A step of calculating four control target speeds corresponding to the four rollers based on the four steering turning radii and the rotation speeds of the four rollers, (b) The step of outputting the four roller drive commands based on the four control target speeds, Chassis dynamometer.

8. A chassis dynamometer according to claim 7, The steering model controller executes a straight-line control process for roller drive when it is determined by the turning determination process that the vehicle's driving state is the straight-line state. The roller control process includes the straight-line control process, The aforementioned straight-line control process is: (a) The step of setting the four control target speeds corresponding to the four rollers to the same common speed, (b) The step of outputting the four roller drive commands based on the four control target speeds, Chassis dynamometer.

9. A chassis dynamometer according to any one of claims 1 to 8, The steering angle detection mechanism is, A left-side displacement sensor that detects the left tire steering angle of the first-type left tire and obtains the left steering angle information, with the measurement target area of ​​the first-type left tire as the detection target, The system includes a right-side displacement sensor that detects the right tire turning angle of the first-type right tire and obtains the right steering angle information, with the measurement target area of ​​the first-type right tire as the detection target, Chassis dynamometer.

10. A chassis dynamometer according to any one of claims 1 to 8, The steering angle detection mechanism is, The aforementioned rotation model controller, A steering angle sensor that detects the steering angle of the vehicle during steering operation and obtains steering angle information indicating the detected steering angle, It includes a steering angle conversion table having multiple types of angle pair information, wherein the multiple types of angle pair information is information indicating multiple types of left tire turning angles and multiple types of right tire turning angles in a format corresponding to multiple types of steering angles, each of the multiple types of left tire turning angles corresponding to the left tire steering angle, and each of the multiple types of right tire turning angles corresponding to the right tire steering angle. The turning model controller further performs steering angle recognition processing to recognize the left steering angle information and the right steering angle information, The steering angle recognition process involves referring to the steering angle conversion table to select the left tire turning angle and the right tire turning angle from among the multiple types of left tire turning angles and the multiple types of right tire turning angles that correspond to the steering angle indicated by the steering angle information, and recognizing the information indicating the selected left tire turning angle and right tire turning angle as the left steering angle information and the right steering angle information. Chassis dynamometer.

Images