JP7786313B2 - Analysis device, analysis method, and computer program - Google Patents

Description

This disclosure relates to an analysis device, an analysis method, and a computer program.

Patent Document 1 discloses a wire harness analysis device that uses the finite element method to calculate the shape of a wire harness routed inside a vehicle. The wire harness analysis device disclosed in Patent Document 1 discretizes the wire harness, which is considered to be a continuum, into multiple beam elements, assigns corrected physical property values to the beam elements taking into account the internal condition of the wire harness or the working environment when the wire harness is assembled into the vehicle, and calculates the shape of the wire harness based on the corrected physical property values.

Japanese Patent Application Laid-Open No. 2015-99573

For example, in electric parking brake (EPB) systems and anti-lock brake (ABS) systems installed in vehicles, the parking brake unit and wheel speed sensors inside the wheel house are electrically connected to an on-board control device located on the vehicle body by electrically insulated cables. Such cables are stretched between components fixed to bearings that rotatably support the wheels, such as suspension arms and parking brake units, and between parts of the vehicle body near the wheel house, and are subject to deformation in response to suspension movement. When the cables deform, the amount of deformation at the ends of the cables tends to be large, increasing the likelihood of damage such as breaks or torn coatings occurring near the ends. However, the wire harness analysis device disclosed in Patent Document 1 uniformly models the entire wire harness, including its ends, as beam elements, which may result in insufficient estimation of deformation at the ends.

An analysis device according to one aspect of the present disclosure is an analysis device that analyzes a cable having a first end attached to a support mechanism that rotatably supports a wheel of a vehicle or a component fixed to the support mechanism, and a second end attached to a vehicle body connected to the support mechanism via a suspension, the analysis device comprising: a setting unit that sets the position and angle at which the first end of the cable is attached to the support mechanism or a component fixed to the support mechanism, and the position and angle at which the second end is attached to the vehicle body; and a setting unit that sets the position and angle of the first end and the position and angle of the second end of the cable that have been set by the setting unit, and a setting unit that sets the position and angle of the suspension. The system includes an estimation unit that estimates a first shape, which is the shape when the suspension is in a first state, and a second shape, which is the shape when the suspension is in a second state; and a calculation unit that calculates the amount of change in curvature of the cable based on the first shape and the second shape of the cable estimated by the estimation unit. The estimation unit estimates the first shape and the second shape using a cable model that virtually simulates the entire cable with uniform physical properties, and a first member model and a second member model that virtually simulate, as solid elements, a first member attached to the first end of the cable and a second member attached to the second end of the cable.

The present disclosure can be realized not only as an analysis device having the characteristic configuration described above, but also as an analysis method including characteristic steps, or as a computer program for causing a computer to execute the characteristic steps. The present disclosure can also be realized as a system including the analysis device, or as a semiconductor integrated circuit in which part or all of the analysis device is implemented.

This disclosure makes it possible to accurately estimate deformation at the end of a cable.

FIG. 1 is a diagram for explaining a cable to be analyzed by an analysis device according to an embodiment. FIG. 2 is a block diagram illustrating an example of a hardware configuration of the analysis device according to the embodiment. FIG. 3 is a functional block diagram illustrating an example of functions of the analysis device according to the embodiment. FIG. 4 is a diagram for explaining the shape of the cable routed in the vehicle. FIG. 5 is a diagram showing an example of the entire analysis model of a cable. FIG. 6 is a graph showing an example of the curvature and the amount of change in curvature of a cable. FIG. 7 is a flowchart illustrating an example of an analysis process performed by the analysis device according to the embodiment.

Overview of the embodiments of the present disclosure
The following provides an outline of embodiments of the present disclosure.

(1) The analysis device according to this embodiment is an analysis device that analyzes a cable having a first end attached to a support mechanism that rotatably supports a wheel of a vehicle or a component fixed to the support mechanism, and a second end attached to a vehicle body connected to the support mechanism via a suspension, and includes a setting unit that sets the position and angle at which the first end of the cable is attached to the support mechanism or a component fixed to the support mechanism, and the position and angle at which the second end is attached to the vehicle body; and a setting unit that sets the position and angle of the first end and the position and angle of the second end of the cable that have been set by the setting unit, and a setting unit that sets the position and angle of the suspension when the first end is attached to the vehicle body. The system includes an estimation unit that estimates a first shape, which is the shape when the suspension is in a first state, and a second shape, which is the shape when the suspension is in a second state, and a calculation unit that calculates the amount of change in curvature of the cable based on the first and second shapes of the cable estimated by the estimation unit. The estimation unit estimates the first and second shapes using a cable model that virtually simulates the entire cable with uniform physical properties, and a first member model and a second member model that virtually simulate, as solid elements, a first member attached to the first end of the cable and a second member attached to the second end of the cable. As a result, because the first and second members are modeled as solid elements, it is possible to accurately estimate the deformation of the cable in the vicinity of the first and second members.

(2) In (1) above, the physical properties may include flexural rigidity measured from an actual cable or a modulus of elasticity calculated from the flexural rigidity. This allows the cable to be accurately modeled using the actual measured value of the cable's flexural rigidity.

(3) In (1) or (2) above, the cable model may be modeled using beam elements defined by beam differential equations. This allows the cable to be modeled as simple beam elements, thereby reducing the computational load for estimating the first and second shapes of the cable.

(4) In any one of (1) to (3) above, the first state of the suspension may be a state in which the suspension is at its minimum design length, and the second state may be a state in which the suspension is at its maximum design length. This makes it possible to calculate the maximum change in cable curvature due to suspension movement.

(5) In any one of (1) to (4) above, the analysis device may further include a determination unit that determines the flex life of the cable based on the amount of change in curvature of the cable calculated by the calculation unit. This makes it possible to determine the flex life of the cable through simulation.

(6) In (5) above, the determination unit may determine the flex life of the cable using the relationship between the amount of curvature change and the flex life obtained by performing a flex test on an actual cable. This allows the flex life of the cable to be accurately estimated through simulation.

(7) In any one of (1) to (6) above, the analysis device may further include an output unit that outputs a graph showing the relationship between the longitudinal position of the cable and the amount of curvature change calculated by the calculation unit. This allows the user to check the amount of curvature change for each position on the cable.

(8) The analysis method according to this embodiment is an analysis method for analyzing a cable having a first end attached to a support mechanism that rotatably supports a wheel of a vehicle or a part fixed to the support mechanism, and a second end attached to a vehicle body connected to the support mechanism via a suspension, the analysis method including the steps of setting the position and angle at which the first end of the cable is attached to the support mechanism or the part fixed to the support mechanism, and the position and angle at which the second end is attached to the vehicle body; and analyzing the cable having the position and angle of the first end and the position and angle of the second end set when the suspension is in a first state. The method includes the steps of: estimating a first shape, which is the shape when the suspension is in a first state, and a second shape, which is the shape when the suspension is in a second state; and calculating a change in curvature of the cable based on the estimated first and second shapes of the cable. The estimating step includes estimating the first and second shapes using a cable model that virtually simulates the entire cable with uniform physical properties, and a first member model and a second member model that virtually simulate, as solid elements, a first member attached to the first end of the cable and a second member attached to the second end of the cable. In this way, because the first and second members are modeled as solid elements, it is possible to accurately estimate the deformation of the cable in the vicinity of the first and second members.

(9) A computer program according to this embodiment is a computer program for analyzing a cable having a first end attached to a support mechanism that rotatably supports a wheel of a vehicle or a part fixed to the support mechanism, and a second end attached to a vehicle body connected to the support mechanism via a suspension, the computer including the steps of setting the position and angle at which the first end of the cable is attached to the support mechanism or the part fixed to the support mechanism, and the position and angle at which the second end is attached to the vehicle body; and setting the position and angle of the suspension of the cable for which the position and angle of the first end and the position and angle of the second end have been set. The method executes the steps of: estimating a first shape, which is the shape when the suspension is in a first state, and a second shape, which is the shape when the suspension is in a second state; and calculating a change in curvature of the cable based on the estimated first and second shapes of the cable. The estimating step includes estimating the first shape and the second shape using a cable model that virtually simulates the entire cable with uniform physical properties, and a first member model and a second member model that virtually simulate, as solid elements, a first member attached to the first end of the cable and a second member attached to the second end of the cable. In this way, because the first member and the second member are modeled as solid elements, it is possible to accurately estimate the deformation of the cable in the vicinity of the first member and the second member.

<Details of the embodiment of the present disclosure>
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At least some of the following preferred embodiments may be combined in any desired manner.

[1. Analysis target]
1 is a diagram for explaining a cable to be analyzed by an analysis device according to an embodiment. A cable 70 to be analyzed by the analysis device according to this embodiment is an EPB cable used in an EPB system.

The cable 70 is used to electrically connect the on-board control device 50 located in the body 11 of the vehicle 10 to the parking brake unit 40 located in the wheel house 12. The wheel house 12 houses the wheels 20 connected to the body 11 via suspensions 30. The suspensions 30 include suspension arms 31. The suspension arms 31 are an example of a support mechanism that rotatably supports the wheels 20. The parking brake unit 40 is located on the axles of the wheels 20.

A connecting member 61 is fixed to the suspension arm 31. The connecting member 61 is a member for connecting the first end of the cable 70. A cable 41 extends from the connecting member 61, and the connecting member 61 and the parking brake unit 40 are connected by the cable 41.

The vehicle body 11 is equipped with an on-board control device 50. The on-board control device 50 is a component of the EPB system and controls the parking brake unit 40.

A connection member 62 is fixed to the vehicle body 11. The connection member 62 is a member for connecting the second end of the cable 70. A cable 51 extends from the connection member 62, and the connection member 62 and the on-board control device 50 are connected by the cable 51.

The first end of the cable 70 is connected to the connecting member 61. The second end of the cable 70 is connected to the connecting member 62. This electrically connects the on-board control device 50 and the parking brake unit 40.

A first member 71, which is a reinforcing member made of synthetic resin, is provided at the first end of cable 70. The first member 71 is, for example, a cylinder with an inner diameter the same as the outer diameter of cable 70, and covers the first end of cable 70. The first end of cable 70 is fixed to suspension arm 31 by crimping. However, the first end of cable 70 does not have to be fixed to suspension arm 31. The first end of cable 70 may also be fixed to a component fixed to the suspension arm, which is a support mechanism, such as a brake caliper.

A second member 72, which is a reinforcing member made of synthetic resin, is provided at the second end of the cable 70. The second member 72 is, for example, a cylinder with an inner diameter equal to the outer diameter of the cable 70, and covers the second end of the cable 70. The second end of the cable 70 is fixed to the vehicle body 11 by crimping.

As the suspension 30 expands and contracts, the relative positions of the vehicle body 11 and the wheel 20 change. This causes the cable 70 to deform. Because the second end of the cable 70 is fixed to the vehicle body 11, the positional relationship between the vehicle body 11 and the second end does not change with the movement of the suspension 30. Because the first end of the cable 70 is fixed to the suspension arm 31, the positional relationship between the vehicle body 11 and the first end changes with the movement of the suspension 30. In other words, the second end of the cable 70 fixed to the vehicle body 11 is a fixed end, and the first end of the cable 70 fixed to the suspension arm 31 is a movable end.

Since the direction of suspension movement is fixed, the deformation pattern of cable 70 is also fixed. In other words, cable 70 deforms according to a fixed pattern. Note that the deformation pattern of a cable routed to the front wheels is different from that of a cable routed to the rear wheels. For example, the deformation pattern of a cable routed to the front wheels may be affected not only by the suspension but also by the steering angle of the wheels.

The amount of deformation of the cable 70 is not uniform; there are areas where the amount of deformation is large and areas where the amount of deformation is small. In other words, when the cable 70 deforms, the amount of deformation varies depending on the longitudinal position of the cable 70. For this reason, if the cable 70 is repeatedly deformed by the operation of the suspension, damage such as breakage or tearing of the coating will occur in areas of the cable 70 where the amount of deformation is large.

[2. Hardware configuration of analysis device]
2 is a block diagram showing an example of the hardware configuration of an analysis device 100 according to an embodiment. The analysis device 100 according to this embodiment analyzes a cable 70 using the finite element method. The analysis device 100 includes a processor 101, a non-volatile memory 102, a volatile memory 103, an input device 104, a display device 105, and a communication interface (communication I/F) 106.

The volatile memory 103 is, for example, a semiconductor memory such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory). The non-volatile memory 102 is, for example, a flash memory, a hard disk, or a ROM (Read Only Memory). The non-volatile memory 102 stores an analysis program 201, which is a computer program, and data used to execute the analysis program 201. The functions of the analysis device 100 are realized when the analysis program 201 is executed by the processor 101. The analysis program 201 can be stored in a recording medium such as a flash memory, a ROM, or a CD-ROM. The analysis program 201 enables the processor 101 to analyze the cable 70 using the finite element method.

The processor 101 is, for example, a CPU (Central Processing Unit). However, the processor 101 is not limited to a CPU. The processor 101 may also be a GPU (Graphics Processing Unit). The processor 101 is, for example, a multi-core processor. The processor 101 may also be a single-core processor. The processor 101 may also be, for example, an ASIC (Application Specific Integrated Circuit), or a programmable logic device such as a gate array or FPGA (Field Programmable Gate Array). In this case, the ASIC or programmable logic device is configured to be able to execute the same processing as the analysis program 201.

The non-volatile memory 102 stores a cable model 202 generated by the analysis program 201. The cable model 202 is a model that virtually simulates the entire cable 70 with uniform physical properties. The physical properties of the cable model 202 include bending rigidity. The bending rigidity is a value (actual measurement value) measured from a sample of the cable 70. In a specific example, the bending rigidity is an actual measurement value from a three-point bending test conducted in a low-temperature environment of -30°C. The physical property of the cable model 202 is not limited to bending rigidity, and may also be a modulus of elasticity calculated from the bending rigidity. The modulus of elasticity is calculated from the second moment of area and bending rigidity of the cable model 202.

In this embodiment, the cable model 202 is a beam element. That is, the cable model 202 is a model defined by a beam differential equation.

Furthermore, the non-volatile memory 102 stores a first member model 203 and a second member model 204. The first member model 203 is a model that virtually simulates the first member 71 as a solid element. The second member model 204 is a model that virtually simulates the second member 72 as a solid element. A solid element is an analytical model expressed in three-dimensional form, and is composed of multiple small regions (meshes). Each small region is assigned physical property values such as elastic modulus, Poisson's ratio, and specific gravity.

Attribute data 205 is stored in the non-volatile memory 102. The attribute data 205 is data indicating the attributes of the cable 70. The attributes include, for example, the length, bending stiffness, and Poisson's ratio of the cable 70. The attributes may further include the specific gravity of the cable 70. The bending stiffness included in the attribute data 205 is an actual measured value obtained by a three-point bending test.

The non-volatile memory 102 stores flex life data 206. The flex life data 206 is data showing the relationship between the amount of curvature change and flex life obtained by performing a flex test on a sample of cable 70. In one specific example of a flex test, a sample of cable 70 is placed vertically between two 60 mm diameter mandrels A and B arranged horizontally and parallel to each other, and is bent horizontally 90° so that the upper end abuts the upper side of one mandrel A, and then bent horizontally 90° so that the upper end abuts the upper side of the other mandrel B. This process is repeated in a low-temperature environment of -30°C. The two conductors in the cable are connected and their resistance is measured. The number of flex cycles at which the resistance increases to 10 times or more the initial resistance (one flex cycle is defined as the time it takes to bend the cable to the right, then to the left, and then back to the right) is defined as the flex life. The flex life is an example of an indicator of flex resistance.

Non-volatile memory 102 stores curvature change amount data 207 generated by analysis program 201. Curvature change amount data 207 is data that indicates the relationship between the longitudinal position of cable 70 and the amount of curvature change.

For example, the input device 104 includes a keyboard and a pointing device such as a mouse. The input device 104 may also be a capacitive or pressure-sensitive touchpad overlaid on the screen of the display device 105. The input device 104 is used to input data into the analysis device 100.

The display device 105 includes, for example, a liquid crystal panel or an OEL (organic electroluminescence) panel. The display device 105 can display text or graphic information.

The communication I/F 106 can communicate with external devices. For example, the communication I/F 106 is connected to a CAD (Computer Aided Design) device via a network and can receive CAD data from the CAD device.

[3. Functions of the analysis device]
3 is a functional block diagram showing an example of functions of the analysis device according to the embodiment. When the processor 101 executes the analysis program 201, the analysis device 100 functions as an input unit 111, a setting unit 112, a generation unit 113, an estimation unit 114, a calculation unit 115, a determination unit 116, and an output unit 117.

The input unit 111 is mainly realized by the input device 104 or the communication I/F 106. The output unit 117 is mainly realized by the display device 105. The setting unit 112, generation unit 113, estimation unit 114, calculation unit 115, and determination unit 116 are mainly realized by the processor 101.

The analysis device 100 estimates the shape of the cable 70 attached to the vehicle 10. More specifically, the analysis device 100 estimates the shape of the cable 70 at the time of initial routing (hereinafter referred to as the "initial routing shape"), the shape of the cable 70 at the maximum designed contraction of the suspension 30 (hereinafter referred to as the "full bound shape"), and the shape of the cable 70 at the maximum designed extension of the suspension 30 (hereinafter referred to as the "full rebound shape").

Figure 4 is a diagram illustrating the shape of the cable routed in a vehicle. Figure 4 shows examples of the initial routing shape, full bound shape, and full rebound shape of the cable 70.

When the cable 70 is attached (routed) to the vehicle 10, the suspension 30 is in its natural length state. The initial routing of the cable 70 refers to the state when the cable 70 is first routed to the vehicle 10. In other words, the initial routing shape of the cable 70 is the shape of the cable 70 when the suspension 30 is in its natural length state.

The maximum design compression state of the suspension 30 (hereinafter referred to as "full bound") refers to the state in which the suspension 30 is most compressed as determined by design. The full bound shape of the cable 70 is an example of the first shape.

The maximum design extension of the suspension 30 (hereinafter referred to as "full rebound") refers to the state in which the suspension 30 is most extended as determined by design. The full rebound shape of the cable 70 is an example of the second shape.

To estimate the shape of cable 70, it is necessary to identify the positions and angles of both ends (first end and second end) of cable 70 in three-dimensional space. Therefore, to estimate the initial routing shape of cable 70, it is necessary to identify the attachment position and attachment angle of the first end and the second end on vehicle 10 at the time of initial routing. To estimate the full-bound shape of cable 70, it is necessary to identify the attachment position and attachment angle of the first end and the second end on vehicle 10 at the time of full rebound. To estimate the full-rebound shape of cable 70, it is necessary to identify the attachment position and attachment angle of the first end and the second end on vehicle 10 at the time of full rebound. However, because the second end of cable 70, which is fixed to the vehicle body 11, is a fixed end, the attachment position and attachment angle of the second end are the same at the time of initial routing, full bounce, and full rebound.

For example, a user uses the input device 104 to input the attachment position and attachment angle of the first end and the second end of the cable 70 at each of the initial routing, full bound, and full rebound states into the analysis device 100. In another example, a CAD device (not shown) transmits CAD data, and the analysis device 100 receives the CAD data. The CAD data includes information on the attachment position and attachment angle of the first end and the second end of the cable 70 at each of the initial routing, full bound, and full rebound states. Returning to FIG. 3 , the input unit 111 accepts the attachment position and attachment angle of the first end and the second end of the cable 70 at each of the initial routing, full bound, and full rebound states.

The setting unit 112 sets the input attachment position and attachment angle of the first end and the second end of the cable 70 at each of the initial routing, full bound, and full rebound times. For example, the setting unit 112 stores the attachment position and attachment angle of the first end and the second end of the cable 70 at each of the initial routing, full bound, and full rebound times in the non-volatile memory 102 as setting information.

The generation unit 113 generates the cable model 202. In one specific example, the generation unit 113 generates the cable model 202 using the length, bending stiffness, and Poisson's ratio of the cable 70 included in the attribute data 205. The specific gravity of the cable 70 may also be used to generate the cable model 202.

Figure 5 shows an example of an entire analytical model of a cable. In Figure 5, analytical model 35 is shown as a three-dimensional model of the cable.

The analysis model 35 is composed of a cable model 202, a first member model 203, and a second member model 204.

The cable model 202 is a beam element in the finite element method. That is, the cable model 202 is an element defined as a line. In Figure 5, the cable model 202 is shown as a three-dimensional cylindrical model with a cross-sectional area. As shown in Figure 5, the analysis device 100 displays the cable model 202 as a three-dimensional cylinder on the display device 105, but the actual cable model 202 is a line model with no cross-sectional area. The bending stiffness is used as the elastic modulus in the cable model 202.

The first member model 203 and the second member model 204 are solid elements in the finite element method. That is, the first member model 203 and the second member model 204 are elements with defined three-dimensional shapes. The first member model 203 has a three-dimensional shape that simulates the first member 71, and the second member model 204 has a three-dimensional shape that simulates the second member 72. That is, each of the first member model 203 and the second member model 204 is defined as a cylindrical shape. Each of the first member model 203 and the second member model 204 is divided into multiple small regions. Each small region of the first member model 203 is assigned physical property information (elastic modulus, Poisson's ratio, and specific gravity) that simulates the first member 71, and each small region of the second member model 204 is assigned physical property information (elastic modulus, Poisson's ratio, and specific gravity) that simulates the second member 72.

Returning to FIG. 3, the estimation unit 114 estimates the shape of the cable 70 for which the position and angle of the first end and the position and angle of the second end have been set by the setting unit 112. That is, the estimation unit 114 estimates the initial routing shape, full bound shape, and full rebound shape of the cable 70.

The estimation unit 114 estimates the initial routing shape of the cable 70 based on the attachment position and attachment angle of the first end and the attachment position and attachment angle of the second end of the cable 70 at the time of initial re-routing, which are set by the setting unit 112, the cable model 202, the first member model 203, and the second member model 204. The estimation unit 114 estimates the full-bound shape of the cable 70 based on the attachment position and attachment angle of the first end and the attachment position and attachment angle of the second end of the cable 70 at the time of full-bound, which are set by the setting unit 112, the cable model 202, the first member model 203, and the second member model 204. The estimation unit 114 estimates the full rebound shape of the cable 70 based on the attachment position and attachment angle of the first end and the attachment position and attachment angle of the second end of the cable 70 at full rebound, which are set by the setting unit 112, the cable model 202, the first member model 203, and the second member model 204.

Cable 70 has a structure in which a core wire including at least one insulated wire made of a conductor and an insulating layer covering the conductor is covered with a sheath. The sheath has a two-layer structure, for example, an inner sheath layer and an outer sheath layer covering the inner sheath layer. Because cable 70 has such a complex structure, simulating cable 70 as solid elements also results in a complex analytical model. Therefore, estimating the shape of cable 70 using an analytical model of solid elements requires a large amount of calculation. With the analysis device 100 of this embodiment, the cable model 202 is a beam element that virtually simulates the entire cable 70 with uniform physical properties, thereby reducing the calculation load required to estimate the shape of cable 70.

The first end of the cable 70 is covered by a first member 71, and the second end is covered by a second member 72. When a cable 70 configured in this manner is deformed, the amount of deformation is likely to be large near the boundary between the exposed portion of the cable 70 and the first member 71, and near the boundary between the exposed portion of the cable 70 and the second member 72, making it highly likely that damage such as breakage or tearing of the covering will occur in these areas. The analysis device 100 according to this embodiment virtualizes the first member 71 and the second member 72 in detail as solid elements, making it possible to accurately analyze the portions of the cable 70 that are subject to large deformation and accurately estimate the deformation at the ends of the cable 70.

The calculation unit 115 calculates the amount of change in curvature of the cable 70 based on the full bound shape and full rebound shape of the cable 70 estimated by the estimation unit 114.

Specifically, the calculation unit 115 calculates the curvature for each longitudinal (axial) position of the cable 70 in the estimated full bound shape. Furthermore, the calculation unit 115 calculates the curvature for each longitudinal position of the cable 70 in the estimated full rebound shape. The calculation unit 115 calculates the difference between the curvature at full bound and the curvature at full rebound as the curvature change amount for each longitudinal position of the cable 70.

Figure 6 is a graph showing an example of the curvature and curvature change of a cable. In Figure 6, the vertical axis represents the curvature and curvature change, and the horizontal axis represents the distance from the movable end (first end) as the longitudinal position of the cable 70. Figure 6 shows a graph of the curvature at full bound, a graph of the curvature at full rebound, a graph of the curvature change, and a graph of the torsion change. The cable 70 bends in different directions depending on the part. For this reason, the curvature graph shows the absolute value of the curvature. The cable 70 not only bends due to deformation, but also twists. The torsion change is the difference between the amount of twist of the cable 70 at full bound and the amount of twist of the cable 70 at full rebound.

Returning to Figure 3, the calculation unit 115 generates curvature change amount data 207 indicating the calculated curvature change amount at each position in the longitudinal direction of the cable 70, and stores the generated curvature change amount data 207 in the non-volatile memory 102.

The determination unit 116 determines the flex life of the cable 70 based on the amount of curvature change of the cable 70 calculated by the calculation unit 115. In a specific example, the determination unit 116 determines the flex life of the cable 70 using the relationship between the amount of curvature change and the flex life obtained by performing a flex test on the actual cable 70. In other words, the determination unit 116 determines the flex life of the cable 70 using the flex life data 206.

The output unit 117 outputs the analysis results of the cable 70. Specifically, the display device 105 displays the analysis results of the cable 70. The analysis results include at least one of the curvature change calculated by the calculation unit 115 and the flex life determined by the determination unit 116.

The output unit 117 can output a graph showing the relationship between the longitudinal position of the cable 70 and the amount of curvature change calculated by the calculation unit 115. Specifically, the output unit 117 references the curvature change data 207 stored in the non-volatile memory 102 and outputs a graph of the amount of curvature change. This allows the user to visually grasp the amount of curvature change at each position.

4. Operation of the analysis device
The operation of the analysis device 100 according to this embodiment will be described. The processor 101 performs the following analysis process by executing the analysis program 201. Fig. 7 is a flowchart showing an example of the analysis process performed by the analysis device according to this embodiment.

For example, a user uses the input device 104 to input to the analysis device 100 the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of initial routing, the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full bounce, and the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full rebound. In another example, a CAD device (not shown) transmits CAD data to the analysis device 100. The CAD data includes the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of initial routing, the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full bounce, and the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full rebound. The processor 101 acquires the attachment position and attachment angle of the first end and the second end of the cable 70 at the time of initial routing, the attachment position and attachment angle of the first end and the second end of the cable 70 at the time of full bound, and the attachment position and attachment angle of the first end and the second end of the cable 70 at the time of full rebound (step S101).

The processor 101 sets the input attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of initial routing, the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full bound, and the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full rebound (step S102). For example, the processor 101 generates setting information including the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of initial routing, the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full bound, and the attachment positions and attachment angles of the first end and the second end of the cable 70 at the time of full rebound, and stores the generated setting information in the non-volatile memory 102.

The processor 101 references the attribute data 205 and generates the cable model 202 using the length, bending stiffness, and Poisson's ratio of the cable 70 contained in the attribute data 205 (step S103).

The processor 101 estimates the initial routing shape of the cable 70 using the attachment position and attachment angle of the first end and the second end of the cable 70 at the time of initial routing, the cable model 202, the first component model 203, and the second component model 204. The processor 101 estimates the full-bound shape of the cable 70 using the attachment position and attachment angle of the first end and the second end of the cable 70 at the time of full rebound, the cable model 202, the first component model 203, and the second component model 204. The processor 101 further estimates the full-rebound shape of the cable 70 using the attachment position and attachment angle of the first end and the attachment position and attachment angle of the second end of the cable 70 at the time of full rebound, the cable model 202, the first component model 203, and the second component model 204 (step S104).

The processor 101 calculates the curvature at each position of the cable 70 during full bound, and calculates the curvature at each position of the cable 70 during full rebound. Furthermore, the processor 101 calculates the difference between the curvature at full rebound and the curvature at full rebound as the curvature change amount for each position of the cable 70 (step S105).

The processor 101 generates curvature change amount data 207 indicating the correspondence between the longitudinal position of the cable 70 and the curvature change amount, and stores the generated curvature change amount data 207 in the non-volatile memory 102 (step S106).

The processor 101 references the flex life data 206 and determines the flex life of the cable 70 from the calculated curvature change (step S107). For example, the flex life corresponding to the maximum curvature change is determined as the flex life of the cable 70.

The processor 101 displays the analysis results on the display device 105 (step S108). This completes the analysis process.

5. Modifications
In the above-described embodiment, the cable model 202 is a beam element, but is not limited to this. The cable model 202 does not have to be a beam element as long as it is a model that virtually simulates the entire cable 70 with uniform physical properties. For example, the same physical property values (elastic modulus, Poisson's ratio, specific gravity) may be assigned to each small region of a cylindrical solid element sliced in the axial direction, and this may be used as a cable model.

In the above-described embodiment, the EPB cable was the subject of analysis, but this is not limited to this. For example, the signal cable for transmitting the detection value of the wheel speed sensor may also be the subject of analysis.

[5. Supplementary Notes]
The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims rather than the above-described embodiments, and includes meanings equivalent to the claims and all modifications within the scope thereof.

REFERENCE SIGNS LIST 10 Vehicle 11 Vehicle body 12 Wheel house 20 Wheel 30 Suspension 31 Suspension arm 40 Parking brake unit 41 Cable 50 On-board control device 51 Cable 61, 62 Connection member 70 Cable 71 First member 72 Second member 100 Analysis device 101 Processor 102 Non-volatile memory 103 Volatile memory 104 Input device 105 Display device 106 Communication interface (communication I/F)
REFERENCE SIGNS LIST 111 Input unit 112 Setting unit 113 Generation unit 114 Estimation unit 115 Calculation unit 116 Determination unit 117 Output unit 201 Analysis program 202 Cable model 203 First member model 204 Second member model 205 Attribute data 206 Flexural life data 207 Curvature change amount data

Claims (9)

1. An analysis device for analyzing a cable having a first end attached to a support mechanism that rotatably supports a wheel of a vehicle or a component fixed to the support mechanism, and a second end attached to a vehicle body that is connected to the support mechanism via a suspension,
a setting unit that sets a position and an angle at which the first end of the cable is attached to the support mechanism or a component fixed to the support mechanism, and a position and an angle at which the second end of the cable is attached to the vehicle body;
an estimation unit that estimates a first shape of the cable, the shape being a shape when the suspension is in a first state, and a second shape of the cable, the shape being a shape when the suspension is in a second state, for which the position and angle of the first end and the position and angle of the second end have been set by the setting unit;
a calculation unit that calculates a curvature change amount of the cable based on the first shape and the second shape of the cable estimated by the estimation unit;
Equipped with
the estimation unit includes a cable model that virtually simulates the entire cable with uniform physical properties;
estimating the first shape and the second shape using a first member model and a second member model that virtually simulate, as solid elements, a first member attached to the first end of the cable and a second member attached to the second end of the cable, respectively;
Analysis device. The physical properties include a bending stiffness measured from an actual cable or an elastic modulus calculated from the bending stiffness.
The analysis device according to claim 1 . The cable model is modeled using beam elements defined based on beam differential equations.
The analysis device according to claim 1 . the first state of the suspension is a state in which the suspension is at a minimum design length, and the second state is a state in which the suspension is at a maximum design length;
The analysis device according to claim 1 . the analysis device further includes a determination unit that determines a flex life of the cable based on the amount of change in curvature of the cable calculated by the calculation unit.
The analysis device according to claim 1 . the determining unit determines the flex life of the cable using a relationship between a curvature change amount and a flex life obtained by performing a flex test on an actual cable.
The analysis device according to claim 5 . the analysis device further includes an output unit that outputs a graph showing a relationship between a position in the longitudinal direction of the cable and the curvature change amount calculated by the calculation unit.
The analysis device according to any one of claims 1 to 6. 1. An analysis method for analyzing a cable having a first end attached to a support mechanism that rotatably supports a wheel of a vehicle or a component fixed to the support mechanism, and a second end attached to a vehicle body that is connected to the support mechanism via a suspension, the method comprising:
setting a position and an angle at which the first end of the cable is attached to the support mechanism or a part fixed to the support mechanism, and a position and an angle at which the second end of the cable is attached to the vehicle body;
a step of estimating a first shape of the cable, the first shape being a shape when the suspension is in a first state, and a second shape of the cable, the second shape being a shape when the suspension is in a second state, for which the position and angle of the first end and the position and angle of the second end have been set;
calculating a curvature change amount of the cable based on the estimated first shape and second shape of the cable;
Including,
the estimating step includes estimating the first shape and the second shape using a cable model that virtually simulates the entire cable with uniform physical properties, and a first member model and a second member model that virtually simulate, as solid elements, a first member attached to the first end of the cable and a second member attached to the second end of the cable, respectively.
Analysis method. A computer program for analyzing a cable having a first end attached to a support mechanism that rotatably supports a wheel of a vehicle or a component fixed to the support mechanism, and a second end attached to a vehicle body that is connected to the support mechanism via a suspension, the computer program comprising:
On the computer,
setting a position and an angle at which the first end of the cable is attached to the support mechanism or a part fixed to the support mechanism, and a position and an angle at which the second end of the cable is attached to the vehicle body;
a step of estimating a first shape of the cable, the first shape being a shape when the suspension is in a first state, and a second shape of the cable, the second shape being a shape when the suspension is in a second state, for which the position and angle of the first end and the position and angle of the second end have been set;
calculating a curvature change amount of the cable based on the estimated first shape and second shape of the cable;
Execute
the estimating step includes estimating the first shape and the second shape using a cable model that virtually simulates the entire cable with uniform physical properties, and a first member model and a second member model that virtually simulate, as solid elements, a first member attached to the first end of the cable and a second member attached to the second end of the cable, respectively.
Computer program.