Electric power steering apparatus having load detection function

Abstract

The present invention relates to an electric power steering apparatus having a vehicle load detection function that detects a vehicle load using a vehicle speed, a steering wheel torque detected from a steering wheel sensor included in the electric power steering apparatus, and a motor current detected from an electric power steering motor. A drive signal that regulates a motor current applied to the electric steering motor is output. According to the invention, a vehicle load detection sensing device is not used independently; therefore, the problem of ensuring an external space which is physically separated for arranging a conventional vehicle load detection sensor device when a vehicle steering device is realized and the problem of directly increasing the cost of the steering device due to the arrangement of the sensor device can be solved; particularly, according to the vehicle load detected by using the vehicle speed, the steering wheel torque and the motor current of the electric steering motor, the driving signal for adjusting the motor current applied to the electric steering motor is output, so that the effect of accurately improving the steering performance and the effect of preventing the motor from overheating can be expected.

Description

Technical Field

[0001] The present invention relates to an electric steering device, and more particularly, to an electric steering device having a vehicle load detection function.

[0002] The present invention is the result of the Gangwon-do Electric Vehicle R & D Support Project (Gangwon-do Science and Technology Park No. 2022-397) implemented with the support of the Gangwon-do Science and Technology Park as a Gangwon-do funding source in 2022. Background Art

[0003] Figure 1 The structure of a motor control device of a conventional vehicle electric steering device disclosed in Patent Document 1 (KR10-2022-0064013A) is shown.

[0004] In Figure 1 The motor control device of the conventional vehicle electric steering device shown includes an output adjustment module 20 that adjusts the motor current applied to a motor 40 of the electric steering device from a steering control module 10 of the electric steering device according to a vehicle load detected by a load detection unit 30.

[0005] In the motor control device of the conventional vehicle electric steering device configured as described above, in particular, the load detection unit 30 includes a vehicle height sensor that detects the vehicle height, and the output adjustment module 20 calculates an error between the load detected by the vehicle height sensor of the load detection unit 30 and a set reference value, and adjusts the motor current applied to the motor 40 according to a result of comparing the calculated error with a set value, thereby ensuring steering performance and motor overheat protection.

[0006] However, in the motor control device of the conventional vehicle electric steering device disclosed in the above Patent Document 1 (KR10-2022-0064013A), the vehicle height sensor that detects the vehicle height included in the load detection unit 30 is not provided inside the steering device, but is provided to physically separate the space, so there is a problem of increasing the physical implementation difficulty of the steering device.

[0007] In addition, since a vehicle height sensor that was not previously provided is separately configured, there is a problem of directly increasing the cost of the steering device. Summary of the Invention

[0008] [Problems to be Solved]

[0009] The present invention is for solving the above-described conventional problems, and an object of the present invention is to provide an electric power steering device having a vehicle load detection function, which detects a vehicle load by using a vehicle speed, a steering wheel torque detected from a steering wheel sensor included in the electric power steering device, and a motor current detected from an electric power steering motor, and outputs a drive signal for adjusting the motor current applied to the electric power steering motor.

[0010] [Means for Solving the Problem]

[0011] In order to achieve the object of the present invention described above, an electric power steering device having a vehicle load detection function according to the present invention includes: a steering wheel sensor that adjusts and detects a steering wheel torque according to a steering angle of the steering wheel; an electric power steering motor that is driven by a drive signal for adjusting a motor current to rotate the steering wheel; and a steering controller that outputs the drive signal when detecting the steering wheel torque.

[0012] In the electric power steering device having a vehicle load detection function according to the present invention, the steering controller includes: a preprocessing unit that filters a vehicle speed signal, the steering wheel torque signal, and a motor current signal detected from the electric power steering motor respectively to extract meaningful signal components; a signal classification unit that classifies the steering wheel torque signal and the motor current signal extracted by the preprocessing unit to correspond to a pre-specified vehicle speed range; a torque / current calculation unit that performs an integration operation on the steering wheel torque signal and the motor current signal classified by the signal classification unit according to the vehicle speed range to calculate a steering wheel torque value and a motor current value; a current / torque ratio calculation unit that calculates a current torque ratio by using the steering wheel torque value and the motor current value calculated by the torque / current calculation unit, the current torque ratio being a ratio of the assistance of the electric power steering motor in the total steering wheel torque generated by adjusting the steering angle of the steering wheel; a comparison unit that compares the current torque ratio calculated by the current / torque ratio calculation unit with a tolerance ratio of the vehicle specified in advance to determine whether the vehicle load increases or decreases; and a drive signal output control unit that outputs a drive signal for adjusting the motor current applied to the electric power steering motor according to the determination of whether the vehicle load increases or decreases by the comparison unit.

[0013] In the electric power steering device having a vehicle load detection function according to the present invention, the preprocessing unit receives the vehicle speed signal through vehicle CAN (Controller Area Network) communication.

[0014] In the electric power steering device having a vehicle load detection function according to the present invention, the preprocessing unit performs filtering to eliminate abnormal high-frequency noise components included in the vehicle speed signal, the steering wheel torque signal, and the motor current signal respectively to extract meaningful signal components.

[0015] In the electric power steering apparatus with a vehicle load detection function according to the present invention, the preprocessing unit performs DC component filtering to remove the average value of the signal components in the motor current signal that do not contain meaningful information, so as to extract the signal components with only meaningful information from the motor current signal.

[0016] In the electric power steering apparatus with a vehicle load detection function according to the present invention, the torque / current calculation unit differentiates the effective intervals in the steering wheel torque signal and the motor current signal, and performs an integration operation for each interval to calculate the steering wheel torque value for each interval and the motor current value for each interval.

[0017] In the electric power steering apparatus with a vehicle load detection function according to the present invention, the torque / current ratio calculation unit calculates the current torque ratio by using the average values of the steering wheel torque values for each interval and the motor current values for each interval obtained by differentiating the effective intervals in the steering wheel torque signal and the motor current signal in the torque / current calculation unit and performing an integration operation for each interval, that is, the average value of the steering wheel torque values for each interval and the average value of the current values for each interval.

[0018] In the electric power steering apparatus with a vehicle load detection function according to the present invention, the drive signal output control unit outputs a drive signal that increases the motor current applied to the electric power steering motor according to the vehicle load increase ratio if it is determined by the comparison unit that the vehicle load has increased.

[0019] In the electric power steering apparatus with a vehicle load detection function according to the present invention, the drive signal output control unit outputs a drive signal that decreases the motor current applied to the electric power steering motor according to the vehicle load decrease ratio if it is determined by the comparison unit that the vehicle load has decreased.

[0020] In the electric power steering apparatus with a vehicle load detection function according to the present invention, the drive signal output control unit outputs a drive signal that adjusts the motor current applied to the electric power steering motor to be the same as that before the determination if it is determined by the comparison unit that there is no change in the vehicle load increase or decrease.

[0021] [Effects of the Invention]

[0022] In the present invention, since a vehicle load detection sensing device is not used alone, problems such as the need to ensure an externally separated space for setting up a conventional vehicle load detection sensing device when implementing a vehicle steering device and the direct increase in the cost of the steering device due to the configuration of the sensing device can be eliminated. In particular, according to the vehicle load detected by using the vehicle speed, the steering wheel torque, and the motor current of the electric power steering motor, a drive signal for adjusting the motor current applied to the electric power steering motor is output, so that effects such as accurately improving the steering performance and preventing the motor from overheating can be expected. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a block diagram showing the structure of a motor control device of a conventional vehicle electric power steering device.

[0024] Figure 2 FIG. is an embodiment showing the structure of an electric power steering device with a vehicle load detection function according to the present invention.

[0025] Figure 3 FIG. shows Figure 2 a block diagram of the structure of a steering controller.

[0026] Figure 4 FIG. illustrates Figure 1 the operation of a preprocessing unit.

[0027] Figure 5 FIG. illustrates Figure 1 the operation of a signal classification unit.

[0028] Figure 6 FIG. illustrates Figure 1 the operation of a torque / current calculation unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0030] The electric power steering device with a vehicle load detection function according to the present invention described below is not limited to the following embodiments, and its technical idea covers the scope that can be variably implemented by those having ordinary knowledge in the technical field without exceeding the technical gist required in the claims.

[0031] Referring to Figures 2 to 3 , the electric power steering device 100 with a vehicle load detection function according to the present invention includes a steering wheel sensor 110, an electric power steering motor 120, and a steering controller 130. The steering controller 130 includes a preprocessing unit 131, a signal classification unit 132, a torque / current calculation unit 133, a current / torque ratio calculation unit 134, a comparison unit 135, and a drive signal output control unit 136.

[0032] The steering wheel sensor 110 adjusts the detected steering wheel torque according to the steering angle of the steering wheel 111 and inputs it to the steering controller 130.

[0033] The electric power steering motor 120 is driven by a drive signal output for adjusting the motor current in the steering controller 130 to rotate the steering wheel 111.

[0034] The steering controller 130 outputs the drive signal to drive the electric power steering motor 120 when detecting the steering wheel torque through the steering wheel sensor 110, so as to rotate the steering wheel 111, and further provides a force that helps the driver's steering action.

[0035] The preprocessing unit 131 of the steering controller 130 receives the vehicle speed signal, the steering wheel torque signal, and the motor current signal detected from the electric power steering motor 120, and filters them respectively to extract meaningful signal components.

[0036] The preprocessing unit 131 receives the vehicle speed signal through vehicle CAN (Controller Area Network) communication.

[0037] The signal classification unit 132 of the steering controller 130 classifies the steering wheel torque signal and the motor current signal extracted by the preprocessing unit 131 to correspond to a pre-specified vehicle speed range.

[0038] The torque / current calculation unit 133 of the steering controller 130 performs an integration operation on the steering wheel torque signal and the motor current signal classified according to the vehicle speed range by the signal classification unit 132 to calculate the steering wheel torque value and the motor current value.

[0039] The current / torque ratio calculation unit 134 of the steering controller 130 calculates the current torque ratio by using the steering wheel torque value and the motor current value calculated by the torque / current calculation unit 133. The current torque ratio represents the assist ratio of the electric power steering motor 120 in the total steering wheel torque generated by adjusting the steering angle of the steering wheel 111.

[0040] The comparison unit 135 of the steering controller 130 compares the current torque ratio calculated by the current / torque ratio calculation unit 134 with the tolerance ratio of the vehicle specified in advance to determine whether the vehicle load increases or decreases.

[0041] The drive signal output control unit 136 of the steering controller 130 outputs a drive signal for adjusting the motor current applied to the electric power steering motor 120 according to whether the vehicle load increases or decreases determined by the comparison unit 135.

[0042] The operation of the electric power steering apparatus 100 with a vehicle load detection function according to the present invention configured as described above is as follows.

[0043] When a vehicle to which the electric power steering apparatus 100 with a vehicle load detection function according to the present invention is applied is occupied by a driver alone, or by additional passengers other than the driver, or when other cargo is loaded in addition to the passengers, there is a change in the increase or decrease of the vehicle load.

[0044] When the steering angle of the steering wheel 111 is adjusted before or during driving while the driver is in the vehicle, the steering torque is detected by the steering wheel sensor 110 and input to the preprocessing unit 131 of the steering controller 130.

[0045] In this way, when the steering torque is detected by the steering wheel sensor 110, the steering controller 130 outputs the drive signal to drive the electric power steering motor 120 to rotationally operate the steering wheel 111, thereby providing a force that assists the driver's steering operation.

[0046] At this time, a vehicle speed signal, the steering torque signal, and a motor current signal detected from the electric power steering motor 120 are input to the preprocessing unit 131.

[0047] Accordingly, the preprocessing unit 131 filters the vehicle speed signal, the steering torque signal, and the motor current signal detected from the electric power steering motor 120 respectively to extract meaningful signal components, and transmits them to the signal classification unit 132.

[0048] For reference, Figure 4 is a graph Figure 1 illustrating the operation of the preprocessing unit 131.

[0049] As Figure 4 shown, the preprocessing unit 131 performs filtering to eliminate abnormal high-frequency noise components respectively included in the vehicle speed signal, the steering torque signal, and the motor current signal, and extracts meaningful signal components.

[0050] In particular, as Figure 4 shown, the preprocessing unit 131 performs DC component filtering to eliminate the average value of the signal components that do not contain meaningful information in the motor current signal, and extracts only the signal components with meaningful information in the motor current signal.

[0051] As described above, the vehicle speed signal, the steering wheel torque signal, and the motor current signal extracted by the preprocessing unit 131 are input to the signal classification unit 132, where the steering wheel torque signal and the motor current signal are classified to correspond to a pre-specified vehicle speed range.

[0052] For reference, Figure 5 is a graph showing the operation of the signal classification unit 132, exemplifying the classification of the steering wheel torque signal to correspond to three vehicle speed ranges, such as 0 to 10 km / h, 10 to 30 km / h, and 30 to 60 km / h.

[0053] Although Figure 5 does not exemplify the classification of the motor current signal to correspond to three vehicle speed ranges, such as 0 to 10 km / h, 10 to 30 km / h, and 30 to 60 km / h, the signal classification is performed by the same method as the steering wheel torque signal.

[0054] As described above, the steering wheel torque signal and the motor current signal classified by the signal classification unit 132 according to the vehicle speed range are input to the torque / current calculation unit 133 for integration operation, and then calculated as the steering wheel torque value and the motor current value.

[0055] In particular, at this time, the torque / current calculation unit 133 distinguishes valid intervals in the steering wheel torque signal and the motor current signal, and performs integration operations for each interval, and then calculates the steering wheel torque value for each interval and the motor current value for each interval.

[0056] For reference, Figure 6 is a graph showing the operation of the torque / current calculation unit 133, exemplifying distinguishing a total of 8 intervals with flowing current effective interval lengths from ① to ⑧ in the vehicle speed range of 30 to 60 km / h, and performing integration operations for each of these 8 intervals to calculate the results of 8 steering wheel torque values for each interval and 8 motor current values for each interval.

[0057] As described above, after the torque / current calculation unit 133 distinguishes valid intervals in the steering wheel torque signal and the motor current signal, performs integration operations for each interval to calculate the steering wheel torque value for each interval and the motor current value for each interval, the current / torque ratio calculation unit 134 then calculates the current torque ratio using the steering wheel torque value and the motor current value calculated by the torque / current calculation unit 133, and the current torque ratio represents the assistance ratio of the electric power steering motor 120 in the total steering wheel torque generated by adjusting the steering angle of the steering wheel 111.

[0058] At this time, the torque / current ratio calculation unit 134 calculates the current torque ratio by using the average value of the steering wheel torque values in each interval and the average value of the current values in each interval.

[0059] After calculating the current torque ratio, the comparison unit 135 then compares the current torque ratio calculated by the current / torque ratio calculation unit 134 with the tolerance ratio of the vehicle specified in advance to determine whether the vehicle load increases or decreases, and transmits the determination result to the drive signal output control unit 136.

[0060] If it is determined by the comparison unit 135 that the vehicle load increases, the drive signal output control unit 136 outputs a drive signal that increases the motor current applied to the electric power steering motor 120 according to the vehicle load increase ratio.

[0061] On the contrary, if it is determined by the comparison unit 135 that the vehicle load decreases, the drive signal output control unit 136 outputs a drive signal that decreases the motor current applied to the electric power steering motor 120 according to the vehicle load decrease ratio.

[0062] Differently, if it is determined by the comparison unit 135 that there is no change in the vehicle load increase or decrease, the drive signal output control unit 136 outputs a drive signal that adjusts the motor current applied to the electric power steering motor 120 to the same motor current as before the determination.

[0063] As can be seen from the above, the present invention does not separately use a vehicle load detection sensing device, so the problem of physically separating the external space required to set up the conventional vehicle load detection sensing device when implementing the vehicle steering device and the problem of directly increasing the cost of the steering device due to the configuration of the sensing device can be completely eliminated.

[0064] In particular, the present invention outputs a drive signal for adjusting the motor current applied to the electric power steering motor 120 according to the vehicle load detected by using the vehicle speed, the steering wheel torque, and the motor current of the electric power steering motor, so the effects of accurately improving the steering performance and preventing the motor from overheating can be expected.

Claims

1. An electric steering device with a vehicle load detection function, characterized in that, Comprising: A steering wheel sensor (110) that detects and adjusts the steering torque of the steering wheel (111) according to the steering angle of the steering wheel; An electric power steering motor (120) that is driven by a drive signal for adjusting the motor current to rotate the steering wheel (111); A steering controller (130) that outputs the drive signal when detecting the steering torque; The steering controller (130) includes: A preprocessing unit (131) that receives the vehicle speed signal, the steering torque signal, and the motor current signal detected from the electric power steering motor (120), and filters them respectively to extract meaningful signal components; A signal classification unit (132) that classifies the steering torque signal and the motor current signal extracted by the preprocessing unit (131) to correspond to a pre-specified vehicle speed range; A torque / current calculation unit (133) that performs an integration operation on the steering torque signal and the motor current signal classified by the signal classification unit (132) according to the vehicle speed range to calculate the steering torque value and the motor current value; A current / torque ratio calculation unit (134) that calculates the current torque ratio by using the steering torque value and the motor current value calculated by the torque / current calculation unit (133), where the current torque ratio is the ratio of the assistance of the electric power steering motor (120) in the total steering torque generated by adjusting the steering angle of the steering wheel (111); A comparison unit (135) that compares the current torque ratio calculated by the current / torque ratio calculation unit (134) with the tolerance ratio of the vehicle specified in advance to determine whether the vehicle load increases or decreases; and A drive signal output control unit (136) that outputs a drive signal for adjusting the motor current applied to the electric power steering motor (120) according to the determination of whether the vehicle load increases or decreases by the comparison unit (135).

2. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The preprocessing unit (131) receives the vehicle speed signal through vehicle CAN (Controller Area Network) communication.

3. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The preprocessing unit (131) performs filtering to eliminate abnormal high-frequency noise components included in the vehicle speed signal, the steering torque signal, and the motor current signal respectively, so as to extract meaningful signal components.

4. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The preprocessing unit (131) performs DC component filtering to remove the average value of the signal components that do not contain meaningful information in the motor current signal, so as to extract only the signal components with meaningful information from the motor current signal.

5. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The torque / current calculation unit (133) differentiates the effective intervals in the steering torque signal and the motor current signal, and performs an integration operation on each interval to calculate the steering torque value of each interval and the motor current value of each interval.

6. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The torque / current ratio calculation unit (134) calculates the current torque ratio using the average value of the steering wheel torque values in each interval and the average value of the motor current values in each interval, which are obtained by using the torque / current calculation unit (133) to distinguish the valid intervals in the steering wheel torque signal and the motor current signal and performing integration operations on each interval, that is, the average value of the steering wheel torque values in each interval and the average value of the current values in each interval.

7. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The drive signal output control unit (136) outputs a drive signal that increases the motor current applied to the electric power steering motor (120) according to the vehicle load increase ratio if it is determined by the comparison unit (135) that the vehicle load has increased.

8. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The drive signal output control unit (136) outputs a drive signal that decreases the motor current applied to the electric power steering motor (120) according to the vehicle load decrease ratio if it is determined by the comparison unit (135) that the vehicle load has decreased.

9. The electric steering device with a vehicle load detection function according to claim 1, characterized in that, The drive signal output control unit (136) outputs a drive signal that adjusts the motor current applied to the electric power steering motor (120) to the same value as before the determination if it is determined by the comparison unit (135) that there is no change in the vehicle load increase or decrease.

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