STEERING CONTROL DEVICE AND ELECTRIC POWER STEERING DEVICE

Abstract

Steering control device comprising: an electric motor (110) configured to apply an auxiliary force to the steering of a steering element (101); a torque sensing unit (109) configured to sensing the steering torque (T) of the steering element; a basic drive force setting unit (21) configured to set a basic drive force of the electric motor based on the steering torque detected by the torque sensing unit; a determination unit (222) configured to determine whether a drive force greater than the basic drive force should be set based on a rotational speed (Vm) of the electric motor; an auxiliary drive force setting unit (226) configured to set an auxiliary drive force added to the basic drive force based on a steering angle (θs) of the steering element; and a final drive force setting unit (23) configured toto set a final drive force greater than the basic drive force by adding the auxiliary drive force to the basic drive force according to the determination made by the determination unit, wherein the auxiliary drive force setting unit is configured to calculate a corrected steering angle (θc) by adding the steering angle calculated on the basis of a rotation angle of the electric motor and a corrective steering angle (θt) calculated on the basis of a multiplier of the steering torque detected by the torque sensing unit with a predetermined coefficient, and on the basis of a change (Δθc) of the corrected steering angle, to adjust the auxiliary drive force so that the final drive force overcomes a frictional force generated at the beginning of the steering by the steering element during the transmission of a drive force from the electric motor to a roller wheel (150).

Description

Technical field

[0001] The present invention relates to a steering control device and an electric power steering system. State of the art

[0002] It is known that an electric power steering system includes a friction element. For example, the electric power steering system disclosed in patent literature 1 includes a delay device composed of a gearbox attached to a rotary shaft of an electric motor and another gearbox that is mating with the gearbox and attached to a steering shaft. The electric power steering system disclosed in patent literature 1 performs motor control in which a target current is generated from a vehicle speed and a steering torque in order to produce an auxiliary force. List of citations from patent literature

[0003] Patent Literature 1: Japanese Patent Application - Published Publication No. 2004-338562 Summary of the invention: Technical problem

[0004] A steering control device, such as an electric power steering system, contains a friction element. For this reason, it is feared that the driving force of the electric motor, generated by the required current resulting from the steering torque, may not be able to overcome the frictional force, thus preventing the rack from moving (the wheels do not roll). This can lead to a time delay between, for example, the start of the steering wheel's rotation (steering element) and the start of the power transmission by the electric motor.

[0005] One objective of the present invention is to provide an electric power steering system that can shorten the time until the electric motor begins to apply an auxiliary force in response to the start of operation of the steering element. Solution to the problem

[0006] With the above objective in mind, one aspect of the present invention relates to a steering control device comprising: an electric motor configured to exert an auxiliary force on the steering of a steering element; a torque sensing unit configured to detect the steering torque of the steering element; a base drive force setting unit configured to set a base drive force of the electric motor based on the steering torque detected by the torque sensing unit; and a determination unit configured to determine whether a greater drive force than the base drive force is to be set based on a rotational speed of the electric motor. Advantageous effects of the invention

[0007] According to the present invention, it is possible to shorten the time until the electric motor begins to apply an auxiliary force in response to the start of operation of the steering element. List of characters Fig. Figure 1 is a schematic configuration diagram of an electric power steering system according to the embodiments. Fig. Figure 2 is a schematic configuration diagram of a controller. Fig. Figure 3 is a schematic configuration diagram of an auxiliary current setting unit of the first embodiment. Fig. Figure 4 is a schematic diagram of a characteristic curve representing the correspondence between a relative steering angle and an additional base current. Fig. Figure 5 is a flowchart of a set current adjustment process performed by a set current adjustment unit. Fig. Figure 6 shows the relationship between a steering angle and a steering torque. Fig. Figure 7 shows the relationship between the steering torque and the motion of a rack and pinion shaft. Fig. Figure 8 is a schematic configuration diagram of the auxiliary current setting unit of the second embodiment. Fig. Figure 9 is a schematic diagram of a characteristic curve that represents the correspondence between the relative steering torque and the basic auxiliary current. Fig. Figure 10 is a schematic configuration diagram of the auxiliary current setting unit of the third embodiment. Fig. Figure 11 is a schematic configuration diagram of the auxiliary current setting unit of the fourth embodiment. Fig. Figure 12 is a schematic configuration diagram of the target current setting unit of the fifth embodiment. Description of the embodiments

[0008] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. <Erste Ausführungsform>

[0009] Fig. Figure 1 represents a schematic configuration of an electric power steering system. 100 according to the embodiments.

[0010] The electric power steering 100 (hereinafter referred to simply as "steering device 100") is a steering device for changing the direction of travel of a vehicle in any desired direction. As an example, the steering device 100 the present embodiment in an automobile 1 used, which is an example of the vehicle. Fig. 1 illustrates the automobile 1 View from the front.

[0011] The steering system 100 includes a wheel-like steering wheel (handle) 101, which is an example of the steering element that is operated by a driver to change the direction of travel of the vehicle 1 to change, and a steering shaft 102 , which is connected to the steering wheel 101 is integrated. The steering system 100 It also includes an upper clutch shaft. 103 , which have a universal joint 103a with the steering shaft 102 is coupled, and a lower clutch shaft 108 , which have a universal joint 103b with the upper clutch shaft 103 is coupled. The lower clutch shaft 108 rotates in conjunction with the rotation of the steering wheel 101 .

[0012] The steering system 100 also includes a pull rod 104 , which with the left and right wheel 150 coupled as roller wheels, and a rack and pinion shaft 105 , which is connected to the pull rod 104 is coupled. The steering system 100 It also includes a pinion gear.106a , which uses a rack and pinion mechanism together with the components on the rack and pinion shaft 105 trained rack teeth 105a forms. The pinion 106a is at one lower end of the pinion shaft 106 trained. The pinion shaft 106 By rotating, it exerts a driving force (rack and pinion force) on the rack and pinion shaft. 105 out, to which the left and right wheel 150 be rolled up.

[0013] The steering system 100 It also includes a steering gear. 107 with the pinion shaft 106 . Inside the steering gear 107 is the pinion shaft 106 via a torsion bar 112 with the lower clutch shaft 108 coupled. The steering gear 107 includes a torque sensor 109 , which is an example of the torque sensing unit configured to transmit the torque to the steering wheel 101 applied steering torque Tbased on the relative rotation angles of the lower clutch shaft 108 and the pinion shaft 106 , namely the torsional load on the torsion bar 112 , to capture.

[0014] The steering system 100 It also includes an electric motor. 110 , which is from the steering gear 107 is worn, and incorporates a delay mechanism. 111 , which controls the rotation of the electric motor 110 delayed before he put it on the pinion shaft 106 transmits. The delay mechanism 111 includes a pinion shaft 106 fixed worm gear 111a and a snail 111b , which are connected to an output shaft of the electric motor via a shaft coupling (not shown). 110 is coupled. The electric motor 110 exerts a torque on the pinion shaft 106 out and thus exerts a driving force (rack force) on the rack shaft 105out, which in turn turn the wheels 150 brings it rolling. The electric motor 110 The present embodiment consists of a three-phase brushless motor with a resolver 120 , which outputs a rotation angle signal θms, depending on a motor rotation angle θm , which is a rotation angle of the electric motor 110 is.

[0015] The steering system 100 It also includes a control system. 10 to control the operation of the electric motor 110 The control 10 receives output signals from the aforementioned torque sensor 109 . Via a network (CAN) for communicating signals to control various components of the automobile 1 The installed devices receive the control system. 10 also other signals, including an output signal v from a vehicle speed sensor 170 , which is a vehicle speed Vc recorded, which determines the vehicle's speed1 is.

[0016] The steering system configured as above 100 drives the electric motor 110 based on the torque sensor 109 detected steering torque T on and transmits the driving force (generated torque) of the electric motor 110 on the pinion shaft 106 The driving force (generated torque) of the electric motor 110 It thus assists the driver in steering the steering wheel. 101 That is, the electric motor 110 An assistant exercises control over the steering of the driver's steering wheel. 101 out of. (Controller)

[0017] The control will be 10 explained.

[0018] Fig. Figure 2 shows a schematic configuration of the control system. 10 dar.

[0019] The control 10 is an arithmetic logic unit consisting of a CPU, a ROM, a RAM, a backup RAM, etc.

[0020] The control 10 It receives the input of various signals, including a torque signal Td, which is an output signal derived from the torque sensor above. 109 detected steering torque T is converted, a vehicle speed signal v according to the vehicle speed Vc from the vehicle speed sensor 170 and a rotation angle signal θms from the resolver 120 .

[0021] The control 10 includes a target current setting unit 20 and a control unit 30 Based on signals such as the torque signal Td and the vehicle speed signal v, the target current setting unit calculates (sets) 20 a target current that supplies the electric motor 110 to be supplied. The control unit 30performs various controls, including feedback control based on the set current It, which is provided by the set current setting unit. 20 is calculated. The control 10 It also includes a motor rotation angle calculation unit. 71 and an engine speed calculation unit 72 The motor rotation angle calculation unit 71 calculates a motor rotation angle θm of the electric motor 110 The engine speed calculation unit 72 calculates an engine speed Vm based on the motor rotation angle calculation unit 71 calculated motor rotation angle θm The control 10 It also includes a steering angle calculation unit. 73 , which have a steering angle θs calculated by the steering wheel's rotation angle 101 is. [Set current setting device]

[0022] The target current setting unit 20includes a basic setpoint current setting unit 21 and an additional current setting unit 22 The basic setpoint current setting unit 21 It calculates a basic setpoint current Ib, on which the setting of the setpoint current is based. The auxiliary current setting unit 22 It sets an additional current Ia, which is added to the base setpoint current Ib under predefined conditions that will be described later. The setpoint current setting unit 20 It also includes a final set current setting unit. 23 , which determines the target current that it ultimately sends to the electric motor 110 delivers.

[0023] The basic setpoint current setting unit 21 The basic setpoint current Ib is set based on the torque signal Td and the vehicle speed signal v. For example, the basic setpoint current setting unit... 21 with positive steering torque T a positive base setpoint current Ib, and with a negative steering torque Tsets the basic target current setting unit 21 a negative base setpoint current Ib. The base setpoint current setting unit also sets, by way of example, a negative base setpoint current. 21 for a given absolute value of the steering torque T a larger absolute value of the base setpoint current Ib with decreasing vehicle speed Vc The basic setpoint current setting unit 21 can set a dead zone area in which the base setpoint current Ib is independent of the value of the steering torque. T is set to zero. The basic setpoint current setting unit 21 sets the basic setpoint current Ib, i.e., the basic setpoint current setting unit 21 sets a basic drive force based on the steering torque T .

[0024] The auxiliary current setting unit 22 will be described later.

[0025] The final set current setting unit 23 It sets the target current; it is the sum of the value from the basic target current setting unit. 21set basic target current Ib and the one set by the auxiliary current setting unit 22 set additional current Ia (It = Ib + Ia) . (Controller)

[0026] The control unit 30 Includes: a motor drive control unit (not shown) for controlling the operation of the electric motor. 110 ; a motor drive unit (not shown) for driving the electric motor 110 ; and a motor current sensing unit (not shown) for sensing an actual current Im that is actually supplied to the electric motor 110 flows.

[0027] The motor drive control unit includes a feedback (F / B) control (not shown) that performs feedback control based on the deviation between the set current, which is ultimately determined by the set current adjustment unit. 20 and the electric motor detected by the motor current detection unit 110The actual current supplied is determined. The motor drive control unit also includes a PWM signal generator (not shown) that generates a pulse width modulation (PWM) signal to control the electric motor. 110 to drive.

[0028] The motor drive unit is a so-called inverter and includes, for example, six independent transistors (FETs) as switching elements. Of the six transistors, three are connected between a positive electrode lead of a power source and an electrical coil of each phase, and the other three are connected between a negative electrode lead (ground) and the electrical coil of each phase. The gates of two transistors, selected from the six, are activated to enable the switching operation of the two transistors, thereby controlling the electric motor. 110 is controlled.

[0029] The motor current sensing unit records a value of the actual current Im supplied to the electric motor. 110 flows, based on voltages at both ends of a shunt resistor connected to the motor drive unit. [Engine rotation angle calculation unit, engine speed calculation unit, steering angle calculation unit]

[0030] The motor rotation angle calculation unit 71 calculates the motor rotation angle θm based on the rotation angle signal θms from the resolver 120 .

[0031] The engine speed calculation unit 72 calculates the engine speed Vm of the electric motor 110 from the motor rotation angle calculation unit 71 calculated motor rotation angle θm .

[0032] The steering angle calculation unit 73 calculates the steering angle θs based on the motor rotation angle calculation unit 71calculated motor rotation angle θm The calculation is based on the fact that there is a relationship between the rotation angle (steering angle). θs ) of the steering wheel 101 and the motor rotation angle θm of the electric motor 110 due to the mechanical connection between the steering wheel 101 , the delay mechanism 111 and similar things. For example, the steering angle calculation unit calculates 73 the steering angle θs based on the integrated value of the differences between an actual value and a previous value of the motor rotation angle θm , which is periodically (e.g. every 1 millisecond) by the motor rotation angle calculation unit 71 is calculated.

[0033] Here, a direction is shown in which the relative angle of rotation between the steering wheel changes. 101 (the lower clutch shaft) 108 ) and the pinion shaft 106changes (a direction in which the relative angle of rotation occurs) while the steering wheel 101 from the neutral state to the right, namely the state in which the torsion value of the torsion bar 112 Zero is defined as the positive direction (i.e., the steering torque) T is defined as positive). Also a direction in which the relative angle of rotation between the steering wheel 101 (the lower clutch shaft) 108 ) and the pinion shaft 106 changes (a direction in which the relative angle of rotation occurs) while the steering wheel 101 Turning from the neutral position to the left is defined as the negative direction (i.e., the steering torque). T is defined as negative).

[0034] If that's from the torque sensor 109 detected steering torque T If positive, the base setpoint current Ib is set by the base setpoint current setting unit. 21 calculated to power the electric motor 110to turn to the right, and the flow direction of this basic target flow Ib is defined as a positive direction. That is, when the steering torque T If positive, the basic setpoint current setting unit calculates 21 a positive base set current Ib to generate a torque that drives the electric motor 110 allows turning to the right. If the steering torque T If the value is negative, the basic setpoint current setting unit calculates it. 21 a negative base set current Ib to generate a torque that drives the electric motor 110 can be turned to the left.

[0035] If the steering wheel 101 from the state to the right in which the steering angle θs , which is the turning angle of the steering wheel 101 If zero is the steering angle θs positive, and if the steering wheel 101 When turned to the left from this state, the steering angle θs negative. (Additional current setting unit)

[0036] Fig. Figure 3 is a schematic configuration diagram of the auxiliary current setting unit. 22 of the first embodiment.

[0037] The auxiliary current setting unit 22 includes a filter 221 and an addition determination unit 222 The filter 221 filters the engine speed signal Vms from the engine speed calculation unit 72 The unit of addition determination 222 determined based on the filter's output signal 221 , whether the additional current Ia should be added or not.

[0038] The auxiliary current setting unit 22 It also includes a steering angle correction unit. 223 and a relative steering angle calculation unit 224 The steering angle correction unit 223 calculates a corrected steering angle θc by correcting the steering angle θs The relative steering angle calculation unit224 calculates a relative steering angle Δθc between a previous value θc (n-1) and a current value θc (n) of the corrected steering angle θc based on the steering angle correction unit 223 calculated corrected steering angle θc .

[0039] The auxiliary current setting unit 22 It also includes a basic additional current calculation unit. 225 , which are based on the relative steering angle calculation unit 224 calculated relative steering angle Δθc A basic additional current Iab is calculated, on which the additional current Ia is based.

[0040] The auxiliary current setting unit 22 It also includes a final additional current setting unit. 226 , which calculates the additional current Ia based on the data from the addition order unit 222determination made and of the additional basic current calculation unit 225 The calculated additional base current Iab is finally discontinued.

[0041] The filter 221 It has the function of extracting low-frequency band components that are equal to or lower than a predetermined frequency by removing frequency band components that are higher than the predetermined frequency, and the function of removing predetermined frequency band components in a frequency band that is equal to or lower than the predetermined frequency.

[0042] Based on the filter's output signal 221 determines the unit of addition 222 , to supply the additional current Ia when the motor speed calculation unit 72 calculated engine speed Vm is zero, and determines not to supply the additional current Ia when the motor speed calculation unit is 72calculated engine speed Vm is not zero. The unit of addition determination. 222 It thus serves as an example of the unit of determination based on engine speed. Vm of the electric motor 110 determines whether a driving force greater than a basic driving force caused by the basic setpoint current Ib should be set.

[0043] The steering angle correction unit 223 calculates the corrected steering angle θc based on the steering angle calculation unit 73 calculated steering angle θs and the torque sensor 109 detected steering torque T The steering angle correction unit 223 calculates the corrected steering angle θc by adding the value from the steering angle calculation unit 73 calculated steering angle θs and a corrective steering angle θt according to the torque sensor 109detected steering torque T (θc = θs + θt The corrective steering angle θt corresponds to the steering angle θs , in which the driver controls the steering wheel 101 only one torsion of the torsion bar 112 and no rotation of the pinion shaft 106 The steering angle correction unit causes 223 calculates the corrective steering angle θt by using the torque sensor 109 detected steering torque T with a given coefficient (e.g., the reciprocal of the spring rate of the torsion bar) 112 ) multiplied.

[0044] The relative steering angle calculation unit 224 calculates the relative steering angle Δθc by subtracting the previous value θc (n-1) of the current value θc (n) of the corrected steering angle θc (Δθc = θc (n) - θc (n-1)).

[0045] Fig. Figure 4 is a schematic diagram of a characteristic curve that shows the correspondence between the relative steering angle Δθc and represents the basic additional current Iab.

[0046] The basic additional current calculation unit 225 calculates the basic additional current Iab according to the relative steering angle calculation unit. 224 calculated relative steering angle Δθc For example, the basic additional current calculation unit calculates 225 the basic additional current Iab by adjusting the relative steering angle Aθc, as in Fig. 4. This is shown as an example, inserted into the control chart, and the correspondence between the relative steering angle is shown. Δθc and represents the basic auxiliary current Iab. The characteristic curve can, for example, be empirically generated beforehand and stored in ROM. The basic auxiliary current calculation unit 225 calculates the basic additional current Iab, i.e., the basic additional current calculation unit. 225 relies on the steering angle θs an additional driving force that is added to the basic driving force caused by the basic setpoint current Ib.

[0047] In the Fig. In the exemplary characteristic curve shown in section 4, the basic additional current Iab is positive when the steering wheel 101 is turned to the right. 101 When turned to the right, the steering torque T positive and the base setpoint current Ib is also positive; therefore, the base supplementary current Iab has the same sign as the base setpoint current Ib. On the other hand, the base supplementary current Iab is negative if the steering wheel 101 is turned to the left. 101 When turned to the left, the steering torque T negative and the base setpoint current Ib is also negative; the base supplementary current Iab therefore has the same sign as the base setpoint current Ib.

[0048] If the unit of addition determination 222Determined to supply the additional current Ia, the final additional current setting unit is activated. 226 the additional basic current calculation unit 225 calculated additional base current Iab as additional current Ia. If the addition determination unit 222 Not intended to supply the additional current Ia, the final additional current setting unit 226 reduce the additional current Ia to zero.

[0049] A description of the procedures of a target current setting process, which is carried out by the target current setting unit, is now given. 20 is carried out with reference to a flowchart.

[0050] Fig. Figure 5 is a flowchart of a set current adjustment process initiated by the set current adjustment unit. 20 is executed.

[0051] The target current setting unit 20 performs this target current setting process, for example, for each specified time interval (e.g., 1 millisecond).

[0052] The target current setting unit 20 sets the base target current Ib ( S501 In particular, the basic setpoint current setting unit calculates 21 the basic target current Ib in the manner described above.

[0053] The target current setting unit 20 calculates the corrected steering angle θc ( S502 In particular, the steering angle correction unit calculates 223 the corrected steering angle θc from the steering angle calculation unit 73 calculated steering angle θs and the one from the torque sensor 109 detected steering torque T .

[0054] The target current setting unit then calculates 20 the relative steering angle Δθc ( S503 In particular, the relative steering angle calculation unit subtracts 224 of the current value θc (n) of the in S502 calculated corrected steering angle θc the previous value θc (n-1) of the in S502 calculated corrected steering angle θc in a previous routine of the flowchart.

[0055] The target current setting unit then calculates 20 the basic additional current Iab ( S504 In particular, the basic additional current calculation unit calculates 225 the basic additional current Iab based on the in S503 calculated relative steering angle Δθc .

[0056] The target current setting unit 20 This then determines whether the additional current Ia should be added or not ( S505 ). Especially if the obtained engine speed Vm The unit of measurement for addition is zero. 222 , that the additional current Ia is added (supplied). If the resulting motor speed Vm The unit of measurement for addition is determined by whether it is zero or not. 222 , that the additional current Ia is not added (supplied).

[0057] If the additional current Ia is to be added (Yes in S505 ), sets the target current setting unit 20 the additional base current Iab calculated in S504 as additional current Ia ( S506 If, however, the additional current Ia is not to be added (No in S505 ), sets the target current setting unit 20 the additional current Ia to zero ( S507 ).

[0058] The target current setting unit 20 then sets the target current It ( S508 ) in particular. The final setpoint current setting unit is used in particular. 23 The target current is the value obtained by adding the in S501 set basic setpoint current Ib and the in S506 or S507 The set additional current Ia will be obtained.

[0059] As described above, the steering system 100 The first embodiment provides an example of a steering control device that includes: an electric motor 110, which is configured to provide an assistant to steer the steering wheel 101 to add; a torque sensor 109 , which is configured to control the steering torque T to record; the basic setpoint current setting unit 21 , which is configured to provide a basic driving force for the electric motor 110 based on the torque sensor 109 detected steering torque T to adjust; and the unit of addition determination 222 as an example of a determination unit configured to determine whether a driving force greater than the base driving force is required based on the motor speed Vm of the electric motor 110 to be adjusted. If the engine speed Vm If zero is the unit of addition determination, then this is the unit of addition determination. 222 configured to determine that the driving force should be set to be greater than the base driving force.

[0060] In other words, the steering system 100 The first embodiment includes: the electric motor 110 ; the torque sensor 109 ; and the control 10 , which is configured to, when the electric motor 110 is unable to move under the basic driving force of the electric motor 110 to rotate, which is on the torque sensor 109 detected steering torque T based (i.e., when the engine speed Vm (zero) to set a driving force that is greater than the basic driving force.

[0061] Here, "setting the driving force greater than the basic driving force" means that a driving force in the same direction of rotation as that of the electric motor is added to the basic driving force. 110below the base driving force. In other words, if the base setpoint current Ib, on which the base driving force is based, is positive, the setpoint current is set to the value obtained by adding the positive additional current Ia to the base setpoint current Ib. Conversely, if the base setpoint current Ib, on which the base driving force is based, is negative, the setpoint current is set to the value obtained by adding the negative additional current Ia to the base setpoint current Ib.

[0062] The steering system 100 The first embodiment also includes the steering angle correction unit. 223 , the relative steering angle calculation unit 224 and the basic additional calculation unit 225 as examples of the auxiliary drive force adjustment unit, which is configured to adjust an auxiliary drive force based on the steering angle θs the steering wheel 101 is added to the basic driving force.

[0063] The steering system 100 The first embodiment also includes the final set current setting unit. 23 as an example of the final drive force adjustment unit, which is configured to set a drive force greater than the base drive force by adding an auxiliary drive force to the base drive force. < Functions and effects of the steering device of the embodiment>

[0064] Fig. Figure 6 shows the relationship between the steering angle θs and the steering torque T . Fig. Figure 7 shows the relationship between the steering torque T and the amount of movement of the rack and pinion shaft 105 In each of the Fig. 6 and Fig. 7 will be the relationship in the steering system 100 the present embodiment is indicated by a solid line, and a comparative example in which, in contrast to the steering device 100In the present embodiment, the additional current Ia is not added to the base current It, which is indicated by a dashed line. Fig. 6 shows the case where the steering wheel 101 from the position in which the steering angle θs Zero is when turned to the right.

[0065] In the control device configured above 100 In the first embodiment, the base setpoint current Ib, added to the additional current Ia, is set as the setpoint current It. The rack shaft moves accordingly. 105 compared to the configuration where the additional current Ia is not added (i.e., compared to the comparison example), at the beginning of the steering wheel rotation 101 earlier and lets the wheels 150 roll. That is, even if, for example, the driving force caused by the basic setpoint current Ib (basic driving force), which is based on the torque sensor 109 in response to turning the steering wheel101 detected steering torque T The frictional force between the output shaft of the electric motor is adjusted. 110 attached snail 111b and the one on the pinion shaft 106 attached worm gear 111a cannot overcome this and therefore no rotation of the pinion shaft occurs. 106 The addition of the additional driving force caused by the additional current Ia can affect the pinion shaft. 106 set it in rotation. This can, for example, shorten the time until the electric motor starts. 110 begins, in response to the start of the steering wheel's rotation 101 to provide an assistant. This way the steering system can be adjusted. 100 the first embodiment, as described in the Fig. 6 and Fig. 7 shows, for example, an auxiliary force of the electric motor. 110 apply and increase the steering load at the initial start of the steering wheel rotation 101 reduce (the steering torque) TIt also starts with a small steering angle θs to reduce), and the rack and pinion shaft 105 begins to move earlier. As in the Fig. 6 and Fig. As shown in 7, the steering angle θs in the comparative example also with increased steering torque T when the steering wheel is first turned 101 barely to (the rack and pinion shaft) 105 (barely moves). In contrast, the steering mechanism 100 of the first embodiment the steering angle θs when increasing the steering torque T Make it bigger, which improves the steering feel.

[0066] In the above embodiment, the addition determination unit determines 222 , when the engine speed Vm Zero is to supply the additional current Ia, and when the motor speed Vm The unit of measurement for addition is determined by whether it is zero or not. 222not to supply the additional current Ia. However, the present invention is not limited to this. For example, the addition determination unit can 222 to determine the additional current Ia to supply when an absolute value of the motor speed is specified. Vm does not exceed a predetermined speed, and does not supply the additional current Ia when the absolute value of the motor speed Vm is greater than the predetermined speed. In other words, the motor speed can Vm be considered zero when the absolute value of the engine speed Vm not greater than the specified speed (i.e., a range in which the absolute value of the motor speed Vm (The area that is not larger than the specified rotational speed can be defined as the dead zone area).

[0067] When determining whether the additional current Ia should be supplied, the addition determination unit can be used. 222 in addition to the engine speed Vm on the steering angle speed Vθ and the steering angle θs refer to, for example, the unit of measurement for addition. 222 the steering angle speed Vθ based on the steering angle calculation unit 73 calculated steering angle θs capture.

[0068] Alternatively, the unit of addition determination can be 222 determine that it does not supply the additional current Ia, even though the motor speed Vm zero (or although the absolute value of the engine speed Vm (not exceeding the predetermined rotational speed), when an absolute value of the steering angle speed is used. V0 no more than a predetermined rotational speed and also an absolute value of the steering angle θs no more than a predetermined angle. This can result in a movement of the rack and pinion shaft. 105 and a rolling of the wheels 150 at the steering angle θs (at the absolute value of the steering angle) θs (not exceeding the specified angle) while the driver is steering 101 does not intentionally steer. < Second embodiment>

[0069] The steering system 100 The second embodiment differs from the steering device 100 the first embodiment by the additional current setting unit 22 the target current setting unit 20 the control 10 The following description focuses on the difference to the steering system. 100 the first embodiment and thus allows details of the same parts as those of the steering device 100 the first embodiment away.

[0070] Fig. Figure 8 is a schematic configuration diagram of the auxiliary current setting unit. 22 the second embodiment.

[0071] The auxiliary current setting unit 22The second embodiment differs from the auxiliary current setting unit. 22 of the first embodiment by the method for calculating the basic additional current Iab. The additional current setting unit 22 The second embodiment calculates the basic additional current Iab from the torque sensor. 109 detected steering torque T .

[0072] In particular, the auxiliary current setting unit includes 22 The second embodiment includes a relative steering torque calculation unit. 234 and an additional basic current calculation unit 235 , as in Fig. Figure 8 shows the relative steering torque calculation unit. 234 calculated based on the torque sensor 109 detected steering torque T a relative steering torque ΔT between a previous value T (n-1) of the steering torque T and a current value T (n) of the steering torque TThe basic additional current calculation unit 235 calculates the basic additional current Iab based on the relative steering torque ΔT .

[0073] The relative steering torque calculation unit 234 calculates the relative steering torque ΔT by changing the previous value T (n-1) of the current value T (n) of the torque sensor 109 detected steering torque T subtracted (“ΔT = T (n) - T (n-1)”).

[0074] Fig. Figure 9 is a schematic diagram of a characteristic curve showing the correspondence between the relative steering torque ΔT and represents the basic additional current Iab.

[0075] The basic additional current calculation unit 235 calculates the basic additional current Iab according to that of the relative steering torque calculation unit 234 calculated relative steering torque ΔT For example, the basic additional current calculation unit calculates 235the basic additional current Iab by increasing the relative steering torque ΔT , as in Fig. 9 is shown as an example, inserted into the control chart, and the correspondence between the relative steering torque ΔT and represents the basic additional current Iab. The characteristic curve can, for example, be empirically generated beforehand and stored in ROM. The in Fig. The control map shown in Figure 9 is defined such that, if an absolute value of the relative steering torque is specified, ΔT no more than a predetermined value, an absolute value of the basic additional current Iab with increasing absolute value of the relative steering torque ΔT increases, and when the absolute value of the relative steering torque increases ΔT The basic additional current Iab is constant if it exceeds the specified value. Fig. 9. Exemplary relationship between the relative steering torque ΔT and the basic additional current Iab can vary depending on the vehicle speed Vc can be changed. For example, given a certain relative steering torque... ΔT The basic auxiliary current Iab is set so that it decreases with decreasing vehicle speed. Vc rises.

[0076] The steering system 100 The second embodiment includes the relative steering torque calculation unit. 234 and the basic additional current calculation unit 235 as examples of the auxiliary drive force setting unit, which is configured to set an auxiliary drive force that is in addition to the base drive force based on the torque sensor 109 detected steering torque T is added.

[0077] The steering system configured above 100 The second embodiment uses the base target current Ib added to the additional current Ia as the target current It. This can, for example, shorten the time until the electric motor 110begins, in response to the start of steering wheel operation 101 , such as starting the rotation of the steering wheel 101 to provide an assistant. Furthermore, the additional current Ia increases with increasing steering torque. T , which affects the steering load at the beginning of the journey. 101 can reduce it more precisely. < Third embodiment>

[0078] The steering system 100 The third embodiment differs from the steering device 100 the first embodiment by the additional current setting unit 22 the target current setting unit 20 the control 10 The following description focuses on the difference to the steering system. 100 the first embodiment and thus allows details of the same parts as those of the steering device 100 the first embodiment away.

[0079] Fig. Figure 10 is a schematic configuration diagram of the auxiliary current setting unit. 22 the third embodiment.

[0080] The auxiliary current setting unit 22 The third embodiment differs from the auxiliary current setting unit. 22 the first embodiment in that the additional current setting unit 22 The third embodiment also includes the function of setting the additional base current Iab to zero when predetermined conditions are met.

[0081] In particular, the auxiliary current setting unit includes 22 of the third embodiment an assessment unit 237 and an end basic auxiliary current setting unit 238 The assessment unit 237 It assesses whether predefined conditions, under which the basic auxiliary current Iab should be set to zero, are met. The final basic auxiliary current setting unit 238Finally, the basic additional flow Iab is set based on the judgment of the assessment unit. 237 and the one from the basic auxiliary power unit 225 calculated basic additional current Iab.

[0082] If an absolute value of the steering angle speed Vθ no more than a predetermined speed and also an absolute value of the steering angle θs The assessment unit determines whether the angle is no more than a predetermined angle. 237 that the specified conditions are met. If the absolute value of the steering angle velocity Vθ is greater than the predetermined speed and / or when the absolute value of the steering angle θs The assessment unit evaluates if the angle is larger than the predetermined angle. 237 that the predetermined conditions are not met. For example, the assessment unit 237 the steering angle speed Vθ based on the steering angle calculation unit 73 calculated steering angle θs capture.

[0083] If the assessment unit 237 Determining that the specified conditions are met, the final basic auxiliary current setting unit is activated. 238 the basic additional current Iab, which is connected to the final additional current setting unit 226 The output should be zero. If the assessment unit 237 However, if it determines that the specified conditions are not met, the final basic auxiliary current setting unit is activated. 238 the basic additional current Iab, which is connected to the final additional current setting unit 226 to be issued to the person who is from the basic additional current calculation unit 225 is calculated.

[0084] The steering system 100 The third embodiment includes the steering angle correction unit 223 , the relative steering angle calculation unit 224, the basic additional calculation unit 225 , the assessment unit 237 and the final basic additional calculation unit 238 as examples of the auxiliary drive force adjustment unit, which is configured to adjust an auxiliary drive force that is equal to the base drive force based on the steering angle. θs the steering wheel 101 is added. The assessment unit 237 assessed based on steering angle speed Vθ and the steering angle θs , whether the basic additional current Iab and, if applicable, the additional current Ia (additional driving force) should be set to zero.

[0085] The steering system 100 The third embodiment sets the additional current Ia to zero when the absolute value of the steering angle velocity Vθ is not greater than the specified speed and also the absolute value of the steering angle θs The angle is not greater than the specified angle. This can cause movement of the rack and pinion shaft. 105 and a rolling of the wheels 150 at the steering angle θs (at the absolute value of the steering angle) θs (not exceeding the specified angle) while the driver is steering 101 does not intentionally steer. <Vierte Ausführungsform>

[0086] Fig. Figure 11 is a schematic configuration diagram of the auxiliary current setting unit. 22 the fourth embodiment.

[0087] The steering system 100 The fourth embodiment differs from the steering device 100 the first embodiment by the presence of a steering angle sensor 180 to detect the steering angle θs and through the additional current setting unit 22 the target current setting unit 20 the control 10The following description focuses on the difference to the steering system. 100 the first embodiment and thus allows details of the same parts as those of the steering device 100 the first embodiment. For example, the steering angle sensor 180 The following components are included: a first rotating element (not shown), which is attached to the steering shaft 102 is attached and moves synchronously with the steering shaft 102 rotates; a second rotating element (not shown) that rotates in conjunction with the rotation of the first rotating element; and a magnetoresistive element (not shown) that detects changes in the magnetic field of a magnetized part attached to the second rotating element. The steering angle sensor 180 It outputs sine and cosine signals that correspond to the rotation angle of the steering wheel. 101 are equivalent to.

[0088] The auxiliary current setting unit 22The fourth embodiment differs from the auxiliary current setting unit. 22 of the first embodiment by the method for calculating the relative steering angle Δθc The relative steering angle calculation unit 224 the auxiliary current setting unit 22 The fourth embodiment calculates the relative steering angle Δθc based on a reading from the steering angle sensor 180 measured steering angle θd.

[0089] In particular, the relative steering angle calculation unit calculates 224 of the fourth embodiment the relative steering angle Δθc , by taking a previous value θd (n-1) from a current value θd (n) of the steering angle sensor 180 The recorded steering angle θd (Δθc = θd (n) - θd (n-1) is subtracted.

[0090] The steering system 100 The fourth embodiment includes the relative steering angle calculation unit. 224and the basic additional calculation unit 225 as examples of the auxiliary drive force adjustment unit, which is configured to adjust an auxiliary drive force based on the steering angle θs the steering wheel 101 The base driving force is added. The relative steering angle calculation unit. 224 sets the basic additional current Iab and possibly the additional current Ia (additional drive force) based on the steering angle sensor reading 180 detected steering angle θd, which is the steering angle θs recorded.

[0091] The auxiliary current setting unit 22 The fourth embodiment calculates the relative steering angle Δθc based on the steering angle sensor 180 detected steering angle θd, which is the steering angle θs It detects and calculates the additional base current Iab based on this relative steering angle. Δθc This allows the additional current Ia, which is used for operating the steering wheel, to be used. 101 It can be adjusted more precisely by the driver. <Fünfte Ausführungsform>

[0092] Fig. Figure 12 is a schematic configuration diagram of the set current setting unit. 20 the fifth embodiment.

[0093] The steering system 100 The fifth embodiment differs from the steering device 100 of the first embodiment with regard to the set current setting unit 20 The following description focuses on the difference to the steering system. 100 the first embodiment and thus allows details of the same parts as those of the steering device 100 the first embodiment away.

[0094] The target current setting unit 20 The fifth embodiment includes: the basic setpoint current setting unit 21 ; a filter 24; and a unit of determination 25 , which determines whether the basic setpoint current setting unit 21 The set basic target current Ib is to be set as the target current that ultimately supplies the electric motor 110 is supplied. The set current setting unit 20 The fifth embodiment also includes a final setpoint flow determination unit. 26 , which determines the target current based on the data from the determining unit 25 The determination finally applied to the electric motor 110 supplies.

[0095] The filter 24 It has the same function as the filter. 221 of the first embodiment.

[0096] Based on initial values ​​from the filter 24 determines the unit of determination 25 , to supply the basic target current Ib when the motor speed calculation unit 72 calculated engine speed Vm is not zero. On the other hand, the unit of determination determines 25 based on the filter's initial values 24 , to supply a current other than the base setpoint current Ib when the motor speed calculation unit 72 calculated engine speed Vm Zero. The unit of determination. 25 It thus serves as an example of the unit of determination based on engine speed. Vm of the electric motor 110 determines whether a greater driving force than the basic driving force caused by the basic setpoint current Ib should be set. Alternatively, the unit of determination can be 25 determine that it delivers a current that differs from the base set current Ib when an absolute value of the motor speed is specified. Vm is no more than a predetermined speed, and supplies the basic set current Ib when the absolute value of the motor speed Vm greater than the predetermined rotational speed.

[0097] If the unit of determination 25 determined to supply the basic target flow Ib, determines the final target flow determination unit 26 the basic target current Ib as target current It, which finally supplies the electric motor 110 is supplied. On the other hand, if the unit of determination 25 The unit of measurement determines the final setpoint current determination unit, which determines the current to be supplied that differs from the base setpoint current Ib. 26 a large current Ig, which is larger than the base set current Ib as set current It, which is ultimately supplied to the electric motor 110 is supplied.

[0098] For example, the final setpoint current determination unit 26 the large current Ig according to one of the following two methods ( 1 ) and (2) calculate: (1) The final setpoint flow determination unit 26It can calculate the large current Ig based on the torque signal Td and the vehicle speed signal v. The final target current determination unit 26 sets a positive large current Ig when the steering torque T positive, and a negative large current Ig when the steering torque T is negative. For a given absolute value of the steering torque T sets the final target flow determination unit 26 a larger absolute value of the large current Ig as the vehicle speed decreases Vc Given a specific absolute value of the steering torque T makes the final target current determination unit 26 the absolute value of the large current Ig is greater than that of the base setpoint current Ib.

[0099] The control 10 may include a basic characteristic curve for calculating the basic setpoint current Ib and a large current characteristic curve for calculating the large current Ig, and, depending on whether the unit of determination25 Once the system has decided to supply the base setpoint current Ib, the characteristic curves are switched to calculate the current that is ultimately set as the setpoint current It. The large current control map can be created such that, for a given absolute value of the steering torque, T and a given vehicle speed Vc The absolute value of the large current Ig, calculated using the large current control curve, is greater than that of the base setpoint current Ib, calculated using the base control curve. In other words, the large current characteristic can be prepared such that, for a given absolute value of the steering torque, T and a given vehicle speed Vc the driving force of the electric motor 110, which is caused by the large current Ig calculated using the large current characteristic curve, becomes greater than the driving force caused by the basic setpoint current Ib calculated using the basic characteristic curve. If the unit of determination 25 The setpoint adjustment unit determines the delivery of the base setpoint current Ib. 20 In the fifth embodiment, the base setpoint current Ib calculated using the base control card is used as the setpoint current, which is ultimately supplied to the electric motor. 110 is supplied, and when the unit of determination 25 The setpoint adjustment unit determines which current is to be supplied that differs from the base setpoint current Ib. 20 In the fifth embodiment, the large current Ig, which was calculated using the large current characteristic curve, is the target current that is finally supplied to the electric motor. 110 is supplied.

[0100] (2) The final setpoint flow determination unit 26can multiply the basic set current Ib by a predetermined gain G that is greater than 1 to obtain the large current Ig (= Ib x G).

[0101] The steering system configured above 100 In the fifth embodiment, the large current Ig, which is greater than the base setpoint current Ib, is defined as the setpoint current It. This can, for example, shorten the time until the electric motor 110 begins, in response to the start of steering wheel operation 101 , such as starting the rotation of the steering wheel 101 to find an assistant.

[0102] The differences of the auxiliary current setting unit 22 the second to fifth embodiment of the auxiliary current setting unit 22 The first embodiment can be combined with each other.

[0103] The elements of the control 10In the embodiments described above, the features can be implemented either by hardware or software. If some or all elements of the present invention are implemented by software, this software (computer programs) can be provided in the form of a computer-readable storage medium. Examples of computer-readable storage media include portable storage media such as flexible hard disks and CD-ROMs, internal storage devices within the computer such as RAMs and ROMs, and external storage devices such as hard disks. Reference symbol list 10 Control 20 Target current setting unit 21 Basic setpoint current setting unit 22 Auxiliary current setting unit 72 Engine speed calculation unit 109 Torque sensor 111 Delay mechanism 112 Torsion bar 221 filters 222 Addition determination unit 223 Steering angle correction unit 224 Relative steering angle calculation unit 225 Basic additional current calculation unit 226 End auxiliary current setting unit QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2004338562

[0003]

Claims

[1] Steering control device comprising: an electric motor configured to provide assistance to the steering of a steering element; a torque sensing unit configured to detect the steering torque of the steering element; a basic drive force setting unit configured to set a basic drive force of the electric motor based on the steering torque detected by the torque sensing unit; and a determination unit configured to determine whether a driving force greater than the base driving force should be set based on the rotational speed of the electric motor. [2] Steering control device according to claim 1, wherein the determining unit is configured to determine whether the driving force greater than the basic driving force should be set, further based on a steering angular velocity of the steering element and a steering angle of the steering element. [3] Steering control device according to claim 1 or 2, wherein, when the speed of the electric motor is not more than a predetermined speed, the determining unit is configured to determine that the driving force, which is greater than the basic driving force, is to be set. [4] Steering control device according to any one of claims 1 to 3, further comprising: an auxiliary drive force adjustment unit configured to adjust an auxiliary drive force added to the basic drive force based on a steering angle of the steering element; and A final drive force adjustment unit configured to set a drive force greater than the base drive force by adding the auxiliary drive force to the base drive force. [5] Steering control device according to claim 4, wherein the auxiliary drive force adjustment unit is configured to adjust the auxiliary drive force and the steering torque detected by the torque sensing unit on the basis of a rotation angle of the electric motor. [6] Steering control device according to claim 4, wherein the auxiliary drive force adjustment unit is configured to adjust the auxiliary drive force, which is configured to detect the steering angle, on the basis of the steering angle detected by a steering angle detection unit. [7] Steering control device according to any one of claims 1 to 3, further comprising: an auxiliary drive force adjustment unit configured to adjust an auxiliary drive force, to be added to the basic drive force, based on the steering torque detected by the torque sensing unit; and A final drive force adjustment unit configured to set a drive force greater than the base drive force by adding the auxiliary drive force to the base drive force. [8] Steering control device according to one of claims 4 to 7, wherein the auxiliary drive force adjustment unit is configured to determine, based on a steering angle velocity of the steering element and a steering angle of the steering element, whether the auxiliary drive force should be set to zero. [9] Electric power steering configured to control the steering of a steering wheel provided as a steering element in a vehicle using the steering control device according to any one of claims 1 to 8. [10] Electric power steering, comprising: an electric motor configured to provide assistance to the steering of a vehicle's steering wheel; a torque sensing unit configured to detect the steering torque of the steering wheel; and a control system configured to set a drive force greater than the base drive force when the electric motor is unable to rotate below a base drive force based on the steering torque detected by the torque sensing unit.