JP2018081002A - Steering simulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering simulator with which it is possible to easily calculate steering torque in steering simulation.SOLUTION: Provided is a steering simulator 1 for calculating steering torque for adjusting the steering angle of a prescribed vehicle model M to an intended steering angle on the basis of a pre-acquired intended steering angle, comprising: a feed-forward unit 10 for calculating predicted steering torque from the intended steering angle utilizing steering characteristic map data D that includes predicted steering torque previously correlated for each value of intended steering angle; a vehicle model arithmetic unit 11 for inputting the pre-acquired previous steering torque to the vehicle model M and thereby calculating the previous steering angle of the vehicle model M; a feedback unit 12 for calculating corrected steering torque on the basis of a difference between the intended steering angle and the previous steering angle; and a steering torque calculation unit 13 for calculating steering torque on the basis of the predicted steering torque and the corrected steering torque.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering simulation apparatus.

  Conventionally, in order to evaluate a vehicle including a driver for a vehicle control system, a simulation apparatus has been used. Since the steering control simulation device requires power steering control adaptation focusing on the steering torque input to the steering wheel by the driver and evaluation of the steering feeling felt by the driver, a driver model for steering the vehicle by the steering torque is required. Has been.

  Regarding such a driver model, Non-Patent Document 1 describes an operation (steering operation) in which a driver generates a steering torque as a feedback operation with respect to a lateral deviation between a gazing point ahead of a vehicle and a target track, and is described by a transfer function. Thus, a method for calculating the steering torque by the driver is disclosed.

Hidehisa Yoshida and two others, "Fundamental examination of driver model by steering torque (change of course and movement transition model of lane keeping)", Transactions of the Japan Society of Mechanical Engineers, 2015, Vol.81, No.826

  However, the method disclosed in Non-Patent Document 1 requires a large number of parameters in order to calculate the steering torque by the driver. For this reason, it is necessary to adjust many parameter values for each traveling scene, and it is not easy to output steering torque in the steering simulation.

  Therefore, an object of the present invention is to provide a steering simulation device that can easily calculate a steering torque in a steering simulation.

  In order to solve the above-described problem, the present invention provides a steering simulation apparatus that calculates a steering torque for adjusting a steering angle of a predetermined vehicle model to a target steering angle based on a target steering angle acquired in advance. A feed-forward unit that calculates a predicted steering torque from a target steering angle using steering characteristic map data including a predicted steering torque that is associated in advance for each value of the steering angle, and a vehicle model that represents a previously acquired previous steering torque. , The vehicle model calculation unit that calculates the previous steering angle of the vehicle model, the feedback unit that calculates the corrected steering torque based on the difference between the target steering angle and the previous steering angle, the predicted steering torque and the correction A steering torque calculation unit that calculates the steering torque based on the steering torque.

  According to the present invention, it is possible to easily calculate the steering torque in the steering simulation.

It is a block diagram which shows the steering simulation apparatus which concerns on this embodiment. It is a block diagram which shows the calculation process of the steering torque by a steering simulation apparatus. It is a block diagram which shows an example of the process in a feedforward part. It is a block diagram which shows an example of the process in a feedback part. It is a flowchart which shows the calculation process of the steering torque by a steering simulation apparatus. It is a flowchart which shows the calculation process of the last steering angle for feedback by a steering simulation apparatus. It is a block diagram for demonstrating the evaluation method of the steering characteristic of a vehicle model. It is a graph which shows the calculation result of the steering torque at the time of using a 1st vehicle model. It is a graph which shows the calculation result of the steering torque at the time of using a 2nd vehicle model.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

[Configuration of steering simulation device]
FIG. 1 is a block diagram showing a steering simulation apparatus according to this embodiment. FIG. 2 is a block diagram illustrating a steering torque calculation process performed by the steering simulation apparatus. A steering simulation apparatus 1 shown in FIGS. 1 and 2 is an apparatus that calculates a steering torque for adjusting a steering angle of a predetermined vehicle model M to a target steering angle based on a target steering angle acquired in advance.

  The steering simulation apparatus 1 is an arithmetic unit including a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like. The steering simulation device 1 may be composed of a plurality of arithmetic devices. A target steering angle acquisition unit 2 and a storage unit 3 are connected to the steering simulation device 1.

  The target steering angle acquisition unit 2 is connected to a steering simulation device of a conventional steering angle output type driver model, and is a device that acquires a target steering angle output from the conventional steering simulation device. The target steering angle is a steering angle for performing trajectory following traveling with respect to the target trajectory in the vehicle model M. As a steering simulation device of a conventional steering angle output type driver model, a known device can be adopted. The target steering angle acquisition unit 2 outputs the acquired target steering angle to the steering simulation device 1. The target steering angle acquisition unit 2 may be incorporated in the steering simulation device 1.

  The storage unit 3 stores steering characteristic map data D including a predicted steering torque associated in advance for each target steering angle value. The predicted steering torque is a predicted value of the steering torque for adjusting the steering angle of the vehicle model M to the target steering angle. The image of the graph shape of the steering characteristic map data D shown in FIG. 2 is an example. Here, the graph-shaped image is expressed as a closed S-shaped frame, but it may be a single curve.

  Next, a functional configuration of the steering simulation apparatus 1 will be described. The steering simulation apparatus 1 includes a feedforward unit 10, a vehicle model calculation unit 11, a feedback unit 12, and a steering torque calculation unit 13 as functional configurations.

  The feedforward unit 10 calculates a predicted steering torque based on the target steering angle acquired by the target steering angle acquisition unit 2. The feedforward unit 10 uses the steering characteristic map data D stored in the storage unit 3 to calculate a predicted steering torque from the target steering angle.

  Specifically, when the target steering angle is input from the target steering angle acquisition unit 2, the feedforward unit 10 reads the steering characteristic map data D from the storage unit 3 and uses the steering characteristic map data D to perform target steering. A predicted steering torque associated with the corner in advance is calculated.

  Here, FIG. 3 is a block diagram showing an example of processing in the feedforward unit 10. As shown in FIG. 3, the steering characteristic map data D includes a spring steering characteristic map data D1 that defines the relationship between the target steering angle and the spring predicted steering torque, and the relationship between the target steering angle and the friction predicted steering torque. The frictional steering characteristic map data D2 to be defined may be decomposed into the steering characteristic map data D3 to be attenuated and the relationship between the target steering angle and the predicted attenuation steering torque is defined. That is, the steering characteristic map data D may be decomposed and handled by an arbitrary method in order to facilitate the calculation process of the feedforward unit 10, for example. Note that the spring amount, the friction amount, and the damping amount are not used as technical terms but are used for convenience.

  In this case, the feedforward unit 10 uses the spring steering characteristic map data D1, the frictional steering characteristic map data D2, and the damping steering characteristic map data D3, respectively, to calculate the spring predicted steering torque from the target steering angle. Then, the predicted friction torque and the predicted attenuation torque are calculated, and the predicted steering torque is calculated by adding them together. The feedforward unit 10 outputs the calculated predicted steering torque to the steering torque calculation unit 13.

  The feedforward unit 10 may calculate the predicted steering torque using the steering characteristic map data D, and does not need to execute feedforward control in a strict sense.

  The vehicle model calculation unit 11 calculates a previous steering angle for feedback using a predetermined vehicle model M. As shown in FIGS. 1 and 2, the vehicle model calculation unit 11 inputs the steering torque (previously acquired previous steering torque) previously calculated by the steering torque calculation unit 13 described later to the vehicle model M, A steering angle (previous steering angle) of the vehicle model M used for feedback is calculated. As the vehicle model M, a known vehicle model used for simulation of the vehicle control system can be adopted as long as it outputs a steering angle with respect to an input of a steering torque.

  The previous steering torque refers to the previously acquired target steering angle (that is, the target steering angle acquired one time before the target steering angle acquired this time) among the steering torques repeatedly calculated in the steering simulation device 1. This corresponds to the steering torque calculated based on. The previous steering angle is a steering angle for feedback calculated by inputting the previous steering torque into the vehicle model M. The vehicle model calculation unit 11 outputs the calculated previous steering angle for feedback to the feedback unit 12.

  The feedback unit 12 calculates a corrected steering torque based on the difference between the target steering angle acquired by the target steering angle acquisition unit 2 and the previous steering angle output from the vehicle model calculation unit 11. The feedback unit 12 uses the previous steering angle fed back from the vehicle model calculation unit 11 in accordance with the previous steering torque to calculate a corrected steering torque used for calculating the current steering torque.

  Specifically, the feedback unit 12 receives the target steering angle from the target steering angle acquisition unit 2. Further, the feedback unit 12 receives the previous steering angle from the vehicle model calculation unit 11. Then, the feedback unit 12 calculates a corrected steering torque based on the difference between the target steering angle and the previous steering angle. The feedback unit 12 uses an initial value set in advance as the previous steering angle when the current simulation is the first time.

Here, FIG. 4 is a block diagram showing an example of processing in the feedback unit 12. As shown in FIG. 4, the feedback unit 12 executes feedback control (PID control) based on the difference between the target steering angle and the previous steering angle to calculate a corrected steering torque. Since PID control is a well-known technique, description thereof is omitted. Examples of parameters (driver model parameter) used in the PID control, 10.0 proportional gain K _p [Nm / rad], the integration time T _i 1.0 [s], the derivative time T _d be 0.1 [s] it can. The parameters are not limited to these values and may be changed as appropriate. The feedback control is not limited to the PID control, and a known control that can calculate the corrected steering torque from the difference between the target steering angle and the previous steering angle can be employed. The feedback unit 12 outputs the calculated corrected steering torque to the steering torque calculation unit 13.

  As shown in FIGS. 1 and 2, the steering torque calculation unit 13 calculates the steering torque based on the predicted steering torque and the corrected steering torque. More specifically, the steering torque calculation unit 13 calculates the steering torque by adding the predicted steering torque and the corrected steering torque. The steering torque calculation unit 13 outputs the calculated steering torque to the vehicle model M.

[Calculation process of steering torque by steering simulation device]
Next, a steering torque calculation process by the steering simulation apparatus 1 according to the present embodiment will be described. FIG. 5 is a flowchart showing a steering torque calculation process performed by the steering simulation apparatus 1. The flowchart shown in FIG. 5 is started when the target steering angle acquisition unit 2 acquires the target steering angle.

  As shown in FIG. 5, in S10, the steering simulation apparatus 1 uses the steering characteristic map data D read from the storage unit 3 by the feedforward unit 10 and uses the target steering angle input by the target steering angle acquisition unit 2. The predicted steering torque is calculated from the angle. The feedforward unit 10 outputs the calculated predicted steering torque to the steering torque calculation unit 13. When the steering simulation apparatus 1 outputs the predicted steering torque to the steering torque calculation unit 13, the steering simulation apparatus 1 proceeds to S12.

  In S12, the steering simulation apparatus 1 uses the feedback unit 12 to calculate a corrected steering torque based on the difference between the target steering angle and the previous steering angle. More specifically, the steering simulation apparatus 1 uses the feedback unit 12 to execute feedback control (PID control) based on the difference between the target steering angle and the previous steering angle to calculate a corrected steering torque. The previous steering angle calculation process will be described later. The steering simulation apparatus 1 outputs the calculated corrected steering torque to the steering torque calculation unit 13. When the steering simulation apparatus 1 outputs the corrected steering torque to the steering torque calculation unit 13, the steering simulation apparatus 1 proceeds to S14.

  In S <b> 14, the steering simulation device 1 causes the steering torque calculation unit 13 to calculate the steering torque based on the predicted steering torque and the corrected steering torque. More specifically, the steering simulation apparatus 1 calculates the steering torque by adding the predicted steering torque and the corrected steering torque by the steering torque calculation unit 13. Thereafter, the steering simulation apparatus 1 ends the calculation process of the steering torque corresponding to the target steering angle acquired this time by the target steering angle acquisition unit 2 and repeats the flowchart shown in FIG. 5 to calculate the next steering torque. Execute the process.

  Next, the calculation process of the previous steering angle for feedback by the steering simulation apparatus 1 according to the present embodiment will be described. FIG. 6 is a flowchart showing the calculation processing of the previous steering angle for feedback by the steering simulation device. The flowchart shown in FIG. 6 is executed every time the flowchart shown in FIG. 5 is executed and the steering torque is calculated.

  As shown in FIG. 6, in S <b> 20, the steering simulation apparatus 1 inputs the previous steering torque calculated by the steering torque calculation unit 13 to the vehicle model M by the vehicle model calculation unit 11. When the previous steering torque is input to the vehicle model M, the steering simulation device 1 proceeds to S22.

  In S <b> 22, the steering simulation device 1 calculates a previous steering angle of the vehicle model M by executing a simulation of the vehicle control system based on the previous steering torque input to the vehicle model M by the vehicle model calculation unit 11. The steering simulation apparatus 1 outputs the calculated previous steering angle for feedback to the feedback unit 12. Thereafter, the steering simulation apparatus 1 ends the previous steering angle calculation process.

[Effect of steering simulation device]
According to the steering simulation apparatus 1 according to the present embodiment described above, the predicted steering torque is calculated from the target steering angle using the steering characteristic map data D including the predicted steering torque that is associated in advance for each target steering angle value. As compared with the conventional method using a driver model as disclosed in the above non-patent document, it is not necessary to adjust a large number of parameters for the output of the steering torque in the steering simulation. The steering torque can be easily calculated. Thereby, according to the steering simulation device 1, a highly versatile steering simulation of the steering torque input model can be provided.

[Usage example of steering simulation device]
Then, the usage example of the steering simulation apparatus 1 is demonstrated. By using the steering simulation device 1, it is possible to evaluate the steering characteristics of various vehicle models (the relationship between the steering torque input to the vehicle model and the steering angle output from the vehicle model). That is, at the vehicle design stage, a vehicle model corresponding to the vehicle structure under design is generated, and the steering characteristics of the vehicle model are evaluated using the steering simulation device 1 so that the evaluation result is utilized in the vehicle design. Can do.

  FIG. 7 is a block diagram for explaining a method for evaluating the steering characteristics of the vehicle model. FIG. 8 is a graph showing the calculation result of the steering torque when the first vehicle model M1 is used. FIG. 9 is a graph showing a calculation result of the steering torque when the second vehicle model M2 is used. Here, the steering characteristic map data D is set to have an ideal steering characteristic. The first vehicle model M1 and the second vehicle model M2 are vehicle models corresponding to the vehicle structure under design. The first vehicle model M1 and the second vehicle model M2 have different steering characteristics.

  In FIG. 8, the vertical axis represents the steering torque, and the horizontal axis represents the vehicle travel distance (simulated travel distance). In FIG. 8, the final steering torque calculated by the steering torque calculation unit 13 of the steering simulation apparatus 1 is indicated by a one-dot chain line. Further, the predicted steering torque calculated by the feedforward unit 10 is indicated by a broken line, and the corrected steering torque calculated by the feedback unit 12 is indicated by a solid line.

  As shown in FIG. 8, when the first vehicle model M1 is used as the vehicle model of the steering simulation apparatus 1, the corrected steering torque is a value near zero and is finally calculated as the predicted steering torque. The difference with the steering torque is relatively small. This means that there is almost no difference between the steering angle (previous steering angle) obtained by inputting the final steering torque to the first vehicle model M1 and the target steering angle, and correction by feedback is small. Further, it means that the predicted steering torque calculated using the steering characteristic map data D of ideal steering characteristics can be adopted as the final steering torque almost as it is. That is, the result of FIG. 8 shows that the steering characteristic of the first vehicle model M1 can be evaluated as close to the ideal steering characteristic of the steering characteristic map data D.

  On the other hand, as shown in FIG. 9, when the second vehicle model M2 is used as the vehicle model, the corrected steering torque is a value away from zero and is finally calculated as the predicted steering torque. The difference from the steering torque is relatively large. This means that the difference between the steering angle obtained by inputting the final steering torque to the second vehicle model M2 and the target steering angle is large, and there are many corrections by feedback. Further, the predicted steering torque calculated using the steering characteristic map data D having ideal steering characteristics cannot be used as it is as the final steering torque, and the steering angle of the second vehicle model M2 is brought close to the target steering angle. Means that feedback always needs to be corrected. That is, the result of FIG. 9 shows that it can be evaluated that the steering characteristic of the second vehicle model M2 deviates from the ideal steering characteristic of the steering characteristic map data D.

  As described above, the steering simulation device 1 can be used to evaluate the steering characteristics of the vehicle model corresponding to the vehicle structure under design.

[Modification of steering simulation device]
As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment mentioned above. The present invention can be implemented in various forms including various modifications and improvements based on the knowledge of those skilled in the art including the above-described embodiments.

  For example, the feedforward unit 10 of the steering simulation apparatus 1 may use different steering characteristic map data depending on the steering state. In this case, the storage unit 3 applies the first steering characteristic map data applied when the steering is increased (when the target steering angle is increased) and when the steering is returned (the target steering angle is decreased). Second steering characteristic map data to be applied to the second steering characteristic map data.

  In addition, the steering simulation device 1 includes a steering determination unit that determines whether the steering is increased or returned based on the target steering angle history. The steering simulation device 1 calculates the predicted steering torque from the target steering angle using the first steering characteristic map data when it is determined by the steering determination unit that the steering is increasing. When it is determined by the steering determination unit that the steering is being returned, the steering simulation device 1 calculates the predicted steering torque from the target steering angle using the second steering characteristic map data. Since there is a case where the vehicle has a configuration in which there is a difference in steering characteristics between when the steering is increased and when the steering is returned, the first steering characteristic map data or the second steering is considered in consideration of the steering state. A more useful steering simulation can be performed by using the characteristic map data.

  Further, the steering characteristic map data D may be stored in the steering simulation device 1. In this case, the storage simulation unit 1 may not be connected to the steering simulation device 1.

  DESCRIPTION OF SYMBOLS 1 ... Steering simulation apparatus, 10 ... Feed forward part, 11 ... Vehicle model calculating part, 12 ... Feedback part, 13 ... Steering torque calculation part, D ... Steering characteristic map data, M ... Vehicle model.

Claims (1)

A steering simulation device for calculating a steering torque for adjusting a steering angle of a predetermined vehicle model to the target steering angle based on a target steering angle acquired in advance;
A feedforward unit that calculates the predicted steering torque from the target steering angle using steering characteristic map data including a predicted steering torque associated in advance for each value of the target steering angle;
A vehicle model calculation unit that calculates a previous steering angle of the vehicle model by inputting the previous steering torque acquired in advance into the vehicle model;
A feedback unit that calculates a corrected steering torque based on a difference between the target steering angle and the previous steering angle;
A steering torque calculator that calculates the steering torque based on the predicted steering torque and the corrected steering torque;
A steering simulation device comprising:

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