JP5180000B2 - Tire tester drive control method and tire tester - Google Patents

Description

  The present invention relates to a drive control method and a tire testing machine for a tire testing machine for performing a test by changing the slip ratio of a tire with respect to a simulated road surface.

Conventionally, a tire shaft (spindle shaft) on which a tire is mounted is rotated by a tire driving motor, and a driving drum having a pseudo road surface on which the tire is grounded is rotated by a pseudo road surface motor different from the tire driving motor. A tire testing machine that can be used is disclosed in Patent Document 1.
In this tire testing machine, with the tire in contact with the simulated road surface, the tire rotation speed (the tire speed) and the rotation speed of the driving drum (the driving drum speed) are made different from each other so that the tire is simulated on the simulated road surface. Various tests of the tire can be performed while slipping on.

In this test, by adjusting the speed difference between the tire speed and the drive drum speed, the degree to which the tire slips on the simulated road surface, that is, the slip ratio can be changed.
US Pat. No. 6,584,835

However, when the tire speed and the drive drum speed are adjusted so that the slip ratio becomes a desired value (when the slip ratio is changed), the tire surface condition (tread condition) and the ground contact with the simulated road surface of the tire When the situation or the like changes, an abnormal load fluctuation may be applied to the tire driving motor that rotates the tire. In some cases, stick slip may be caused and a great load may be applied to the tire testing machine.
Therefore, in view of the above problems, the present invention performs a test with a slip ratio as wide as possible without applying a great overload to the tire drive motor when a tire test is performed by changing the slip ratio. An object of the present invention is to provide a tire testing machine drive control method and a tire testing machine that can be performed.

  In order to achieve the above object, the present invention has taken the following measures. That is, a tire driving motor that rotates a tire via a tire shaft, a pseudo road surface driving motor that moves a pseudo road surface, and the tire slip rate with respect to the movement of the pseudo road surface is a predetermined value. A drive test method for a tire testing machine comprising a controller for changing a rotation speed of the tire by giving a rotation command to a drive motor, wherein the tire is applied to the tire according to a slip ratio of the tire when the rotation command is given. Estimating the longitudinal force, obtaining a torque limit value for the tire drive motor based on the estimated longitudinal force estimate, and providing the rotation command to change the tire rotation speed to limit the torque of the tire drive motor The torque limit value is applied to the above.

  The torque limit value is preferably obtained from the equation (1).

Obtaining a torque acting as an external force from the tire side on the pseudo road surface driving motor when the tire is rotated by applying braking force or driving force to the tire driving motor by giving the rotation command; It is preferable to add a torque corresponding to the external force to the output torque of the pseudo road surface driving motor.
The simulated road surface is provided so as to be moved by a driving drum driven by the simulated road surface driving motor, and the torque applied to the simulated road surface driving motor is obtained by the equations (2) to (4). Is preferred.

  According to another technical means of the present invention, a tire driving motor that rotates a tire shaft, a pseudo road surface driving motor that moves a simulated road surface, and a tire slip ratio with respect to the movement of the simulated road surface is a preset target value. And a controller for changing the rotation speed of the tire by giving a rotation command to the tire driving motor, wherein the controller changes the rotation speed of the tire in accordance with the slip ratio. Accordingly, a rotation command value calculation unit for determining a rotation command to be given to the tire driving motor, a longitudinal force estimation unit for estimating a longitudinal force applied to the tire when the rotation command is given, and the tire based on the estimated longitudinal force A torque limit value setting unit for setting a torque limit value for the drive motor, and the rotation command to change the rotation speed of the tire drive motor. Wherein there is applied a torque limit value in that it includes a torque limiting unit for applying a torque limitation on the tire driving electric motor when the.

  The controller acts as an external force from the tire side on the pseudo road surface driving motor when the tire is rotated by applying a braking force or a driving force to the tire driving motor by giving the rotation command. It is preferable that an action torque calculation unit for obtaining torque and a torque addition unit for adding torque corresponding to the external force calculated by the action torque calculation unit to the output torque of the pseudo road surface driving motor.

  According to the present invention, when a tire test is performed by changing the slip ratio, the test can be performed with a slip ratio as wide as possible without imposing a great overload on the tire driving motor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows a tire testing machine.
FIG. 1 shows the overall configuration of a tire testing machine. In the following description, the vertical direction in FIG. 1 is the vertical direction or vertical direction, the horizontal direction in FIG. 1 is the horizontal direction, and the through direction in FIG. 1 is the front-back direction.
As shown in FIG. 1, a tire testing machine 1 includes a road surface moving mechanism 3 that moves a simulated road surface 2, a tire holding mechanism 4 that rotatably holds a tire T, a tire T that is pressed against the simulated road surface 2, a slip angle, A moving mechanism 5 that gives a camber angle or the like, a tire holding mechanism 4, a road surface moving mechanism 3, and a controller 6 that controls the moving mechanism 5 are provided.

  The road surface moving mechanism 3 includes a cylindrical driving drum 10 and a pseudo road surface driving motor 11 that rotationally drives the driving drum 10. The driving drum 10 is disposed below the tire holding mechanism 4, and the pseudo road surface 2 is formed on the outer peripheral surface thereof. The rotation shaft 12 of the drive drum 10 is rotatably supported by the first support base 13. The simulated road surface driving motor 11 is disposed on the right side (right side in FIG. 1) of the driving drum 10 and is fixed to the first support base 13. The rotating shaft 8 of the pseudo road surface driving motor 11 and the rotating shaft 12 of the driving drum 10 are connected via a drive shaft 15 so as to be rotatable together.

The tire holding mechanism 4 is disposed above the road surface moving mechanism 3 and has a tire shaft (spindle shaft) 15 that holds the tire T via a rim (not shown), and a housing that rotatably supports the tire shaft 15. 16, a six-component force meter (load cell) 17 that measures the load and moment of the tire T via the housing 16, and a tire drive motor 18 that rotates the tire shaft 15.
The housing 16 and the load cell 17 are provided below a lifting frame 19 of the moving mechanism 5 that can be lifted and lowered. The lifting frame 19 is supported by a support frame 21 provided on a third support base 20. . The tire drive motor 18 is provided on a fourth support base 22 arranged on the right side of the third support base 20.

The tire shaft 15 (spindle shaft) and the rotating shaft 24 of the tire driving motor 18 are connected to each other via a drive shaft 25 and universal joints provided at both ends thereof, so that the tire shaft 15 and the rotating shaft 24 are rotatable together.
In performing the tire test with the tire testing machine 1 described above, first, the tire T is mounted on the tire shaft 15 via the rim, and then the lifting frame 19 of the moving mechanism 5 is lowered to contact the tire T with the simulated road surface 2. Let Then, with the tire T in contact with the simulated road surface 2, the simulated road surface driving motor 11 is driven to rotate the driving drum 10, and the tire driving motor 18 is driven to rotate the tire shaft 15. Various tests can be performed while slipping the tire T against the movement of the simulated road surface 2.

Hereinafter, a tire test method for performing a test while slipping the tire T, and a drive control method at the time of the tire test, including the configuration of the controller 6, will be described in detail.
In the tire test, first, the test conditions for the tire T before and after the slip (the air pressure of the tire T, the load applied to the tire T with respect to the simulated road surface 2, the simulated road surface moving speed, etc.) are the same conditions (values). ).
In addition, in this tire test, as described later, the slip ratio Sr of the tire T with respect to the movement of the simulated road surface 2 is set, and the tire T is slipped at the set slip ratio Sr, while the camber angle and slip of the tire T are set. Various tests are performed such as measuring the load applied to the tire T when the angle is changed by the load cell 17 and observing the state of the tread of the tire T when the slip ratio Sr is sequentially changed. Since the present invention can be applied to all the tests performed while changing the slip ratio Sr, various test modes after changing the slip ratio Sr are not limited to those described above.

In slip operation (sometimes referred to as slip ratio operation) in which the slip ratio Sr is set or changed, first, a state in which the tire T is pressed against the drive drum 10 with a predetermined load (the tire T is grounded on the simulated road surface 2). The tire shaft 15 is rotated with zero torque. That is, in the slip ratio operation, first, after the tire T is brought into contact with the simulated road surface 2, the tire driving motor 18 is not driven but only the simulated road surface driving motor 11 is driven, so that the tire T is moved along the simulated road surface. Turn around.
In this revolving state, the tire T rotates only by the movement of the simulated road surface 2, so the tire T does not slip with respect to the simulated road surface 2, and the slip ratio Sr becomes zero.

Then, the pseudo road surface moving speed (drive drum rotational speed) ωdz and the tire rotational speed (tire rotational speed) ωtz in the accompanying state (when the slip ratio Sr is zero) are measured by a sensor or the like.
Next, in the slip ratio operation, the tire T is intentionally slipped on the simulated road surface 2 by changing the rotation speed of the tire driving motor 18 to change the tire rotation speed.
Now, considering that the tire rotation speed is changed in order to slip the tire T in the slip ratio operation, if the simulated road surface moving speed is constant when the tire rotation speed is changed, the equation (5) is obtained. As described above, the slip ratio Sr of the tire T can be obtained from the tire rotation speed ωt at the time of change (current) and the tire rotation speed ωtz when the slip ratio is zero.

However, in the slip ratio operation, the tire force at the time of changing the tire rotation speed is applied to the simulated road surface driving motor 11 via the simulated road surface 2, and the rotational speed of the simulated road surface driving motor 11 is changed by this external force, The actual situation is that the pseudo road surface moving speed fluctuates as the tire rotational speed changes.
Therefore, in the present invention, in the slip ratio operation, as shown in Expression (6), the tire rotational speed ωtz when the slip ratio Sr is zero, the current simulated road surface moving speed (the simulated road surface moving speed at the time of change) ωd, The tire rotation speed ωtz ′ corresponding to the change in the pseudo road surface movement speed ωdz is calculated from the pseudo road surface movement speed ωdz when the slip ratio Sr is zero. The slip ratio Sr for setting is corrected in consideration of the road surface moving speed.

That is, in the slip ratio operation of the present invention, the rotation command is sent from the controller 6 to the tire drive motor 18 so that the slip ratio Sr obtained by the equation (6) becomes the target value (preset value) used in the tire test. To increase or decrease the tire rotation speed.
As described above, the tire test is performed by appropriately setting the slip ratio Sr in the slip ratio operation. Looking at this slip ratio operation in more detail, as shown in FIG. 2, the slip ratio operation includes three types of operation: a sweep operation, a step operation, and a fixed operation. As described above, the sweep operation, step operation, and fixed operation are common in that the slip ratio Sr is set. However, in each operation, the slip ratio Sr is within a predetermined time (within one step). The degree of change is different.

  As shown in FIG. 2A, the sweep operation is an operation in which the slip rate Sr is gradually increased or decreased within a predetermined time (in one step) until the final step rate (final step rate) set in one step. As shown in FIG. 2B, in the step operation, the slip rate Sr is increased or decreased stepwise until the final step rate is reached within a predetermined time (within one step), and the step rate once increased or decreased is set. The operation is held for a certain time. As shown in FIG. 2 (c), in the fixed operation, within a predetermined time (in one step), the step rate is increased or decreased all at once to the final step rate, and then the final step rate is changed to the end of the operation. It is driving to maintain.

Further, in the sweep operation, the step operation, and the fixed operation, there are a single swing operation and a double swing operation.
Here, the slip ratio Sr when the tire rotation speed is increased is set on the plus side, and the slip ratio when the tire rotation speed is decreased with reference to zero slip ratio in which the tire T does not slip with respect to the simulated road surface 2 When Sr is set to the minus side, the single swing operation is an operation in which the tire rotation speed is fixed to either increase or decrease and the slip rate Sr is changed to one of the plus side and the minus side. The double swing operation is an operation that both increases and decreases the tire rotation speed, and changes the slip ratio Sr to both the plus side and the minus side.

Therefore, when the test is performed by slipping the tire T, the sweep operation, the step operation, and the fixed operation are tested, and the swing operation, the step operation, and the fixed operation are performed in each of the sweep operation, the step operation, and the fixed operation. The test is performed while changing the slip ratio Sr in the vibration operation.
When the target value of the slip ratio Sr is changed in each of the sweep operation, the step operation, and the fixed operation, the longitudinal force applied to the tire according to the target value every time the slip ratio is changed. Is going to be estimated.

  Specifically, as described above, when the rotation command is given from the controller 6 to the tire driving motor 18 corresponding to the tire rotation speed so that the slip ratio becomes the target value, the tire T is set according to the target value of the slip ratio. Estimate the longitudinal force applied to. The estimated longitudinal force applied to the tire T is obtained by equation (8).

Equation (8) is obtained by experiments or the like. The internal coefficient varies depending on the type of tire T and the like, and is in the range of 0.2 to 0.3 for PC tire T (passenger car tire T), preferably 0.25, and TB tire T (truck / bus) ) Is in the range of 0.08 to 0.2, preferably 0.12, and the larger the tire T, the smaller the internal coefficient. The internal coefficient is set in a range of 0.3 to 0.08 depending on test conditions.
A torque limit value for the tire drive motor 1818 is obtained by the equation (1) based on the longitudinal force estimated value obtained by the equation (8).

  The tire rolling radius is a distance from the simulated road surface to the wheel center of the tire as shown in the formula (1). However, since it is difficult to actually measure the tire rolling radius Tr in the tire test, the formula (9) is used in this embodiment. Thus, the tire rolling radius Tr is obtained.

In the slip ratio operation, the upper limit value of the output torque of the tire driving motor 18 when the tire rotation speed is changed by the tire driving motor 18 is set as the torque limit value obtained by the equation (1).
As described above, in the present invention, when the tire rotation speed is changed by the tire drive motor 18 so that the slip ratio Sr becomes the target value, the torque of the tire drive motor 18 is expressed by the equation (9). The required torque limit value is not exceeded.
The controller 6 includes a rotation command value calculation unit 30, a longitudinal force estimation unit 31, a torque limit value setting unit 32, and a first torque limit unit 33.

The rotation command value calculation unit 30 determines a rotation command to be given to the tire drive motor 18 so that the slip ratio Sr becomes a set target value. Specifically, the rotation command value calculation unit 30 changes the tire rotation speed ωt using Equation (5) and Equation (6) so that the target slip rate Sr is given when the tire slip test is performed. Is determined, and the rotational speed of the tire driving electric motor 18 for determining the tire rotational speed ωt is determined.
Specifically, as shown in FIG. 3, the rotation command value calculation unit 30 drives the tire based on the current rotation speed (tire rotation speed) of the tire drive motor 18 and the tire rotation speed obtained from the target slip ratio Sr. The rotation designated value is obtained by multiplying the difference between the rotation speed of the motor 18 and the target value by a gain. The rotation command value calculation unit 30 outputs the calculated rotation command value to the first torque limiting unit 33.

The longitudinal force estimation unit 31 estimates the longitudinal force applied to the tire T based on the target value of the slip ratio Sr. When the slip ratio Sr is given, the tire is calculated by the equation (8) using the slip ratio Sr. Find the longitudinal force of T.
The torque limit value setting unit 32 obtains a torque limit value for the tire drive motor 18 by the formula (1) based on the longitudinal force estimated by the longitudinal force estimation unit 31, and the torque limit value is set to the first torque limit unit. To 33.
The first torque limiter 33 uses the torque limit value obtained by the torque limit value setting unit 32 as the torque in the rotation command of the tire drive motor 18 when the rotation speed of the tire drive motor 18 is changed by the rotation command. The limit is imposed on the output torque of the tire drive motor 18.

  That is, when a rotation command is given to the tire drive motor 18 based on the rotation command value from the rotation command value calculation unit 30, the first torque limiting unit 33 first sets the tire drive motor 18 in accordance with this rotation command. It is determined whether the output torque of the tire driving motor 18 when driven does not exceed the torque limit value. Then, when the output torque does not exceed the torque limit value, the first torque limiter 33 is based on the rotation command value given from the rotation command value calculation unit 30 via the current control unit 37 and the tire drive motor 18. When the output torque exceeds the torque limit value, the tire drive motor 18 is rotated at the torque limit value torque.

  According to the tire testing machine 1 of the present invention, when a rotation command is given by changing the slip ratio, the longitudinal force applied to the tire is estimated according to the slip ratio, and the tire is based on the estimated longitudinal force estimated value. Since the torque limit value for the drive motor 18 is obtained and the torque limit value is applied to the torque limit of the tire drive motor 18 when a rotation command is given to change the rotation speed of the tire, the torque drive value is applied to the tire drive motor 18. The test can be performed with a slip ratio as wide as possible without applying a great overload. That is, in the present invention, since the torque limit value for the tire drive motor 18 is known from the longitudinal force applied to the tire when the slip ratio is changed, the slip ratio is greatly changed as long as the performance of the tire drive motor 18 permits. It became possible.

[Second Embodiment]
4 and 5 show the tire testing machine 1 in the second embodiment.
The controller 6 in the tire testing machine 1 includes an action torque calculation unit 34 and a torque addition unit 35 in addition to the rotation command value calculation unit 30, the longitudinal force estimation unit 31, and the first torque limiting unit 33.
The acting torque calculation unit 34 acts as an external force from the tire side on the pseudo road surface driving motor when a rotation command is given and the tire is rotated by applying braking force or driving force to the tire driving motor 18. Torque (sometimes called working torque) is obtained. In other words, the acting torque calculation unit 34 obtains the acting torque that acts on the side of the pseudo road surface driving motor 11 when the tire driving motor 18 is rotated so that the slip ratio Sr is set to the target value. . Specifically, the working torque calculation unit 34 generates the generated torque Tn generated in the tire driving motor 18 as shown in the equations (2) and (3) when the tire T is rotated at a predetermined slip ratio Sr. Is used to determine the torque (working torque) Tdm acting on the side of the pseudo road surface motor 11 during slipping.

Gr is a reduction ratio of the speed reducer connected to the pseudo road surface motor 11.
The torque adding unit 35 adds an operating torque corresponding to the external force calculated by the operating torque calculating unit 34 to the output torque of the pseudo road surface driving motor 11 by feedforward or feedback, as shown in Expression (4). , Applying a correction coefficient to the action torque Tdm calculated by the action torque calculation unit 34, and adding the action torque (FF) corrected by the correction coefficient to the output torque of the pseudo road surface driving motor 11 as a feedforward component or a feedback component. is there. The correction coefficient ranges from 0.95 to 1.05. In this embodiment, the correction coefficient is 1.0, and Tdm = FF.

  Specifically, as shown in FIG. 5, when the controller 6 drives the simulated road surface driving motor 11, the simulated road surface driving for keeping the current rotational speed of the simulated road surface driving motor 11 and the simulated road surface moving speed constant. A rotation command value is obtained by multiplying the difference between the rotation speed of the motor 11 and the target value by a control gain. At this time, the torque adding unit 35 of the controller 6 adds the corrected operating torque FF calculated by the operating torque calculating unit 34 to the output torque corresponding to the rotation command value for the pseudo road surface driving motor 11. That is, the corrected action torque FF corresponding to the external force calculated by the action torque calculation unit 34 is added by feedforward to the output torque of the pseudo road surface driving motor 11 by the torque addition unit 35. The working torque FF may be added to the output torque of the pseudo road surface driving motor 11 by feedback.

Further, the controller 6 includes a second torque limiting unit 36 that limits the torque of the simulated road surface driving motor 11, and the second torque limiting unit 36 has an output torque of the simulated road surface driving motor 11 that simulates the simulated road surface. It is determined whether or not the torque limit value in the drive motor 11 is exceeded, and the output torque is limited. The pseudo road surface driving motor 11 is driven based on a rotation command given from the controller 6 via the current control unit 37.
In the tire testing machine 1 according to the second embodiment, when the pseudo road surface driving motor 11 is driven together with the driving of the tire driving motor 18, the tire shaft 15 is rotated when the tire shaft 15 is rotated by the driving of the tire driving motor 18. An action torque corresponding to an external force applied to the pseudo road surface driving motor 11 from the side is obtained by the action torque calculation unit 34, and the obtained action torque FF is added to the output torque corresponding to the rotation command value by the torque addition unit 35.

  According to the second embodiment, when the tire rotational speed is changed by driving the tire driving motor 18, the applied torque FF is applied to the pseudo road driving motor 11 in advance, so even if the slip ratio Sr is changed. The rotation speed (pseudo road surface moving speed) of the drive drum 10 can be kept constant with almost no change. In other words, even when an external force from the tire side is applied to the simulated road surface 2 side of the drive drum 10 as the slip ratio Sr is changed (changes the driving force of the tire driving motor 18) in the slip ratio operation, Since the applied torque corresponding to the external force is applied to the simulated road surface driving motor 11, the simulated road surface moving speed does not vary.

  When the tire driving motor 18 side is applied with braking force or driving force, that is, when the braking driving operation is finished and the tire T returns to the state before performing the driving with braking force or driving force, the tire The torque (external force) acting on the simulated road surface 2 side of the drive drum 10 from the T side (tire drive motor 18 side) suddenly disappears. In this embodiment, since the working torque FF is added, if the torque Tn on the tire driving motor 18 side becomes zero, the working torque FF immediately applied to the simulated road surface driving motor 11 becomes zero. That is, simultaneously with the end of the braking drive operation of the tire drive motor 18, the simulated road surface drive motor 11 is switched to control only for keeping the rotation speed (simulated road surface movement speed) of the drive drum 10 constant. As a result, even if the tire drive motor 18 finishes the braking drive operation, there is almost no variation in the simulated road surface moving speed.

Therefore, since the fluctuation of the pseudo road surface moving speed is small even immediately after the braking driving operation of the tire driving motor 18 is finished, the tire driving motor 18 is again subjected to the braking driving operation while maintaining this state. A tire test can be performed immediately. That is, since the speed of the drive drum 10 can be kept constant after the tire test is completed, the next tire test can be performed immediately.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. For example, in the above embodiment, a tire testing machine in which the surface of the rotating drum itself is a simulated road surface is disclosed, but the present invention winds the flat belt around the rotating drum and the driven drum so that the surface of the flat belt is simulated on the simulated road surface. It may be applied to a tire testing machine.

  The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall front view of a tire testing machine according to a first embodiment. It is explanatory drawing of a slip ratio driving | operation, (a) is sweep operation, (b) is step operation, (c) has shown fixed operation. 2 shows a control loop of a tire driving motor. It is a whole front view of the tire testing machine of a 2nd embodiment. 2 shows a control loop of a pseudo road surface driving motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire testing machine 2 Pseudo road surface 3 Road surface movement mechanism 4 Tire holding mechanism 5 Movement mechanism 6 Controller 10 Driving drum 11 Pseudo road surface driving motor 12 Rotating shaft 15 Tire shaft 16 Housing 17 Load cell 18 Tire driving motor 24 Rotating shaft 30 Rotation command Value calculating unit 31 Longitudinal force estimating unit 32 Torque limiting unit 33 Working torque calculating unit 34 Torque adding unit T Tire Sr Slip rate

Claims (6)

A tire driving motor for rotating a tire via a tire shaft; a pseudo road driving motor for moving a pseudo road; and the tire driving so that a slip ratio of the tire with respect to the movement of the pseudo road becomes a predetermined value. A drive control method for a tire testing machine comprising a controller that gives a rotation command to an electric motor to change the rotation speed of the tire,
When the rotation command is given, the longitudinal force applied to the tire is estimated according to the slip ratio of the tire, a torque limit value for the tire driving motor is obtained based on the estimated longitudinal force estimation value, and the rotation command is given. A drive control method for a tire testing machine, wherein the torque limit value is applied to a torque limit of a tire drive motor when changing the rotation speed of the tire. 2. The tire tester drive control method according to claim 1, wherein the torque limit value is obtained by an expression (1). 3.

  Obtaining a torque acting as an external force from the tire side on the pseudo road surface driving motor when the tire is rotated by applying braking force or driving force to the tire driving motor by giving the rotation command; 3. The tire tester drive control method according to claim 1, wherein a torque corresponding to the external force is added to an output torque of the pseudo road surface driving motor. The simulated road surface is provided so as to be moved by a driving drum driven by the simulated road surface driving motor, and the torque applied to the simulated road surface driving motor is obtained by the equations (2) to (4). The drive control method for a tire testing machine according to claim 3.

A tire driving motor that rotates the tire shaft, a pseudo road surface driving motor that moves the simulated road surface, and the tire driving motor that rotates so that the slip ratio of the tire with respect to the movement of the simulated road surface becomes a preset target value. A tire testing machine comprising a controller for giving a command to change the rotational speed of the tire,
The controller includes a rotation command value calculation unit that determines a rotation command to be applied to the tire driving motor to change the rotation speed of the tire according to the slip ratio, and a longitudinal force applied to the tire when the rotation command is given. An estimated longitudinal force estimating unit, a torque limit value setting unit for setting a torque limit value for the tire driving motor based on the estimated longitudinal force, and changing the rotational speed of the tire driving motor by giving the rotation command And a torque limiter that applies a torque limit to the tire driving motor by applying the torque limit value.   The controller provides torque that acts as an external force from the tire side on the pseudo road surface driving motor when the tire is rotated by applying a braking force or a driving force to the tire driving motor by giving the rotation command. And a torque adding unit for adding a torque corresponding to the external force calculated by the operating torque calculating unit to an output torque of the pseudo road surface driving motor. 5. The tire testing machine according to 5.

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