The present invention relates to a steering holding judging apparatus for a vehicle that accurately and immediately judges a steering holding state of a steering system of a vehicle and appropriately performs a current limiting of the motor, and an electric power steering apparatus that is equipped with the above steering holding judging apparatus for the vehicle and provides the steering system of the vehicle with a steering assist force by means of a motor, and in particular to the steering holding judging apparatus for the vehicle that limits a current command value of the motor to the current which can maintain the steering holding state in a state of transiting from a steer-forward to the steering holding state, or detects a transition faster than a detection of entering the steering holding state, releases the current limiting and passes the suitable current when transiting from the steering holding state to the steer-forward, and the electric power steering apparatus equipped with the above steering holding judging apparatus for the vehicle.
An electric power steering apparatus (EPS) which assist-controls a steering system of a vehicle by means of a rotational torque of a motor, applies the steering assist torque to a steering shaft or a rack shaft by means of a transmission mechanism such as gears or a belt through a reduction mechanism. In order to accurately generate the assist control torque (steering assist torque), such a conventional electric power steering apparatus performs a feedback control of a motor current. The feedback control adjusts a voltage supplied to the motor so that a difference between a steering assist command value (a current command value) and a detected motor current value becomes small, and the adjustment of the voltage applied to the motor is generally performed by an adjustment of a duty of a pulse width modulation (PWM) control.
A general configuration of the conventional electric power steering apparatus will be described with reference to
The controller area network (CAN) 40 to send/receive various information and signals on the vehicle is connected to the control unit 30, and it is also possible to receive the vehicle speed Vel from the CAN. Further, a Non-CAN 41 is also possible to connect to the control unit 30, and the Non-CAN 41 sends and receives a communication, analogue/digital signals, electric wave or the like except for the CAN 40.
In such an electric power steering apparatus, the control unit 30 mainly comprises a CPU (Central Processing Unit) (including an MPU (Micro Processor Unit) and an MCU (Micro Controller Unit)), and general functions performed by programs within the CPU are, for example, shown in
The control unit 30 will be described with reference to
A deviation, which is the subtraction result at the subtracting section 32B, ΔI=(Irefm−Im) is proportional and integral (PI)-controlled at a PI-control section 35. The PI-controlled voltage control value Vref is inputted into a PWM-control section 36, whereat a duty thereof is calculated in synchronization with a carrier signal CF. The motor 20 is PWM-driven by an inverter 37 with a PWM signal. The motor current value Im of the motor 20 is detected by a motor current detector 38 and is inputted into the subtracting section 32B for the feedback.
The compensating section 34 adds a self-aligning torque (SAT) 343 detected or estimated and an inertia compensation value at an adding section 344. The addition result is further added with a convergence control value 341 at an adding section 345. The addition result is inputted into the adding section 32A as the compensation signal CM, thereby to improve the characteristics of the current command value.
In such an electric power steering apparatus, since the current that is required to maintain the steering holding state, considering a friction of the column shaft, has a hysteresis characteristic in a transition from the steer-forward to the steering holding state, which no steering has been done (variations of the motor rotational number and the steering assist torque is almost zero, and the motor rotational number is almost zero), it is preferred that the current limiting of the motor should be performed. In the steering holding state, since the large assist torque is not required in normal, it is necessary to surely avoid an unnecessary power consumption and a heat generation.
In a handle end hitting steering state (a rack end state) and the steering holding state, even though a driver does not steer-forward consciously, there is a possibility that a unnecessary steering assist torque is largely generated (an excessive motor current is passed). Then, it is requested that such a state is surely avoided.
As the electric power steering apparatus that decreases the steering holding force of the driver in order to suppress a drift of the vehicle, Japanese Patent No.4815958 B2 (Patent Document 1) is proposed. In Patent Document 1, in order to detect the steering holding state, a steering angle sensor, the vehicle speed sensor, a yaw rate sensor, the torque sensor and the motor rotational angle sensor are used. As the electric power steering apparatus that performs the current limiting of an assist motor in the steering holding state, Japanese Patent No.3915964 B2 (Patent Document 2) is proposed. Estimating values and the like that are calculated by various calculations using a motor voltage detecting value, a motor current detecting value, the torque sensor and the motor rotational angle sensor, are used for detecting the steering holding state by being extremely small values of a torque variation amount and a rotational number variation amount, and a considerable amount of the steering torque.
Patent Document 1: Japanese Patent No.4815958 B2
Patent Document 2: Japanese Patent No.3915964 B2
Using the motor rotational angle sensor as Patent Documents 1 and 2, since the rotational number signal of the motor or the like includes a noise, a low pass filter (LPF) has to be used to decrease an influence of the noise, and then a delay for processing this process is occurred. It is necessary to set a certain threshold (the threshold is set larger than a noise) in order that a state which the motor rotational number is zero, which indicates the steering holding (motor is stopped), is judged. There are problems that the apparatus erroneously judges the steering holding when steering, the apparatus cannot judge the steering holding in the steering holding and the apparatus requires a time in judging the steering holding by being a cause of this threshold.
In the judgment of the steering torque, the steering holding state is judged by an amount (an absolute value) and a changing rate of the steering torque or the like. However, when judging the amount of the steering torque, there are problems that the apparatus can only detect the steering holding state in particular conditions (for example, hitting to the rack end or the like), and in a case that the changing rate of the steering torque, the apparatus erroneously judges the steering holding in gradually changing the steering torque since the judgement is performed by the changing rate against the time.
Further, in the electric power steering apparatus, considering the friction around the column shaft under a state that the motor generates a large torque and stops or almost stops just after transiting from a steer-forward to the steering holding state, there are problems of unnecessary power consumption and heat generation and the like because an excessive current is supplied to the motor in order to maintain the steering holding state.
Furthermore, when transiting from the steering holding state to the steer-forward, it is necessary to detect the transition faster than the detection of entering the steering holding state, release the current limiting, pass the suitable current and easily transit from the steering holding state (a hysteresis width is small).
The present invention has been developed in view of the above-described circumstances, and an object of the present invention is to provide the steering holding judging apparatus for the vehicle that surely judges the steer-forward, the steer-backward and the steering holding state, limits the current which can maintain the steering holding state utilizing the friction of the column shaft when transiting from the steer-forward to the steering holding state, or detects the transition faster than the detection of entering the steering holding state, releases the current limiting, passes the suitable current and easily transits from the steering holding state when transiting from the steering holding state to the steer-forward, and the electric power steering apparatus equipped with the above steering holding judging apparatus for the vehicle.
Further, another object of the present invention is to provide the steering holding judging apparatus for the vehicle that detects or does not erroneously judge the steering holding state under various circumstances which do not occur in unnecessary power consumption and heat generation and the like, can accurately and immediately detect the steering holding state even though the noise is superimposed to the signal which uses to the detection, and can appropriately perform the current limiting of the motor, and the electric power steering apparatus equipped with the steering holding judging apparatus for the vehicle.
The present invention relates to the steering holding judging apparatus, the above-described object of the present invention is achieved by that comprising: at least two steering angle sensors to detect a steering angle of a steering system of a vehicle; and a steering state judging section to calculate a hysteresis central value using a hysteresis signal that sets a hysteresis width to steering signals from the two steering angle sensor, judge a steering state using the hysteresis central value, and output provisional steering information, wherein a steering holding state is detected based on the provisional steering information,
or comprising: a control unit to control a motor, which is coupled to a steering system of a vehicle, by means of a driving current; a steering angle detecting means to detect a column input-side angle and a column output-side angle of the steering system, and output a column input-side angle signal and a column output-side angle signal; a steering state judging section to output steering information and a steering holding signal of the steering system based on the column input-side angle signal and the column output-side angle signal; and a current limiting section to limit the driving current based on the steering information and the steering holding signal, wherein the steering state judging section comprises a hysteresis width setting section to calculate and set hysteresis widths “A” and “B” (<“A”) to the column input-side angle signal and the column output-side angle signal, respectively; a hysteresis central value calculating section to calculate respective hysteresis central values of the hysteresis widths “A” and “B”; a hysteresis filter judging section to turn-ON or turn-OFF a hysteresis trigger signal based on the hysteresis central value of the hysteresis width “A”; and a switching judging section to output the steering information and the steering holding section based on the hysteresis central value of the hysteresis width “A” when the hysteresis signal is OFF, and the hysteresis central values of the hysteresis widths “A” and “B” when the hysteresis signal is ON.
The present invention relates to the electric power steering apparatus that calculates a torque control output current command value based on at least the steering torque, and assist-controls the steering system by driving the motor based on the torque control output current command value, the above-described object of the present invention is achieved by that comprising: the steering holding judging apparatus for the vehicle, or comprising: an angle detecting means to output a column input-side angle signal and a column output-side angle signal of the steering system; a steering state judging section to judge a steering state based on the column input-side angle signal and the column output-side angle signal, and output a steering holding signal and steering information; and a current limiting section to limit the torque control output current command value based on the column input-side angle signal, the column output-side angle signal, the steering holding signal and the steering information, wherein the current limiting section performs a current limiting of the torque control output current command value in a range of a current which a steering holding state is maintained.
According to the electric power steering apparatus of the present invention, the unnecessary power consumption and the heat generation and so on are not occurred since the current command value is limited (gradually changed) in a range of the current which the steering holding state is maintained, considering the friction of the column shaft, when detecting the transition from the steer-forward to the steering holding state.
According to the steering holding judging apparatus for the vehicle of the present invention, the unnecessary power consumption and the heat generation and so on are not occurred since the current command value is limited (gradually changed) in a range of the current which the steering holding state is maintained, considering the friction of the column shaft, when detecting the transition from the steer-forward to the steering holding state. Because at least two detected steering angles (steering angle signals) are applied the hysteresis characteristic, and the steering holding state is detected by using the steering angle signals which are applied the hysteresis characteristic, an immediate detecting is possible without a filter process and the like even if a noise and the like is occurred, and it is possible to perform an accurate detecting in accordance with a steering state.
Further, when transiting from the steering holding state to the steer-forward, the apparatus detects the transition faster than the detection of entering the steering holding state, releases the current limiting, passes the suitable current and easily transits from the steering holding state (the hysteresis width is small).
In the accompanying drawings:
An electric power steering apparatus of the present invention detects a transition from a steer-forward of a handle to a steering holding state, and in the steering holding state, limits (gradually changes) a current command value in a range of a current that can maintain the steering holding state, considering a friction of a column shaft.
The apparatus performs a judging of the steer-forward at the time point t1 (Step S1). In a case of the steer-forward (Step S2), the maximum value of the current command value is latched (Step S3). In a case of not the steer-forward in the Step S2, the process proceeds to a steering holding judging (Step S4).
As a result of the steering holding judging, in a case of the steering holding (Step S200), the current is limited (gradually changed) in a range of a current that can maintain the steering holding state (Step S201, the time point t1 to the time point t2). In the steering holding, by comparing the limiting current value to a target current (a target torque command≃a torque control output current command value), and selecting the smaller current value (minimum current) at the time point t3 (Step S203), the current command value enables to be limited to the current that can maintain the steering holding state (the time point t3 to the time point t4). When the steer-forward is started at the time point t5 (Step S200), the current limiting is immediately released (Step S202) and the process of the current limiting is ended.
As well, in
In the present invention, when detecting the transition from the steer-forward of the handle to the steering holding state, since the current command value is limited (gradually changed) in a range of the current that can maintain the steering holding state, the unnecessary power consumption and the heat generation or the like are not occurred.
Embodiments according to the present invention will be described with reference to the drawings.
The column input-side angle signal θs1 of the handle side and the column output-side angle signal θr1 of an intermediate shaft side are inputted into the steering state judging section 110, and hysteresis processes are performed to the column input-side angle signal θs1 and the column output-side angle signal θr1 by a configuration as shown in
At first, the column input-side angle signal θs1 is described with reference to
The steering holding signal HSU is inputted into a logical product (AND) circuit 116, and the steering information STU is inputted into a logical sum (OR) circuit 117.
Next, the column output-side angle signal θr1 is described with reference to
The steering holding signal HSD is inputted into the logical product (AND) circuit 116, and the steering information STD is inputted into the logical sum (OR) circuit 117.
When the steering holding signals HSU and HSD are outputted as the steering holding state at the same time, the logical product (AND) circuit 116 outputs that the steering holding signal HS is “1” as the steering holding state. When the steering holding signals HSU and HSD are not outputted as the steering holding state at the same time, the logical product (AND) circuit 116 outputs that the steering holding signal HS is “0” as the steering state. When the steering informations STU and STD are outputted as the steer-forward at the same time, the logical sum (OR) circuit 117 outputs that the steering information ST is “0” as the steer-forward state. When the steering informations STU and STD are not outputted as the steer-forward at the same time, the logical sum (OR) circuit 117 outputs that the steering information ST is “1” as the steer-backward state.
The hysteresis width is set by considering following conditions (1) and (2).
Further, the current limiting section 120 has a configuration as shown in for example,
When the steering state is changed from the steering holding to the steer-forward or the steer-backward, the judging signal JS cannot be controlled because the steering holding signal HS is inputted into the limiting judging section 121. The control section selects the same value of the maximum current of the system as the limiting value, and the torque control output current command value “It” is outputted as the limiting current value Ir.
In the present invention, the steering holding is judged based on the column input-side angle signal θs1 of the handle side and the column output-side angle signal θr1 of the intermediate shaft side. In the electric power steering apparatus having a torsion bar, sensors for example, which are shown in
Actually, the column input-side angle signal θs1 and the column output-side angle signal θr1 are outputted through an anti-roll-over process (a process that transforms a saw-tooth wave to a straight line).
In such a configuration, an operation example of the steering state judging section 110 will be described with reference to a flowchart of
At first, a hysteresis process of the column input-side angle signal θs1 is performed (Step S101). Next, a hysteresis process of the column output-side angle signal θr1 is performed (Step S102). Then, the apparatus judges whether the column input-side steering holding judging and the column output-side steering holding judging are the steering holding state at the same time, that is, whether “the column input-side steering holding judging”=“steering holding” and “the column output-side steering holding judging”=“steering holding” are satisfied (Step S110). In a case that the above conditions are coincident, the steering holding signal HS is outputted to “1” that means as the steering holding state (Step S140). In a case that the above conditions are not coincident, the steering holding signal HS is outputted to “0” that means as the steering state (Step S150).
At the same time, as shown in
Next, a hysteresis process of the column input-side angle signal θs1 (Step S101) and a hysteresis process of the column output-side angle signal θr1 (Step S102) in
At first, the column input-side angle signal θs1 is inputted into an angle signal upper-limiting value calculating section 111s, and an angle signal upper-limiting value θUs is calculated (Step S111). The column input-side angle signal θs1 is inputted into an angle signal lower-limiting value calculating sections 112s, and an angle signal lower-limiting value θDs is calculated (Step S112). The calculation order may be changed.
The angle signal upper-limiting value θUs and the angle signal lower-limiting value θDs are inputted into a hysteresis central value calculating section 113s, and a hysteresis central value HCUs is calculated at the hysteresis central value calculating section 113s. It is judged whether the angle signal upper-limiting value θUs is smaller than a previous hysteresis central value (HCUs−1) or not (Step S120). In a case that the angle signal upper-limiting value θUs is smaller than the previous hysteresis central value (HCUs−1), the angle signal upper-limiting value θUs is set as a present hysteresis central value (Step S121). In the Step S120, in a case that it is judged that the angle signal upper-limiting value θUs is not smaller than the previous hysteresis central value (HCUs−1) it is judged whether the angle signal lower-limiting value θDs is the previous hysteresis central value (HCUs−1) or more, or not (Step S122). In a case that it is judged that the angle signal lower-limiting value θDs is the previous hysteresis central value (HCUs−1) or more, the angle signal lower-limiting value θDs is set as the present hysteresis central value (Step S123). In the Step S122, in a case that it is judged that the angle signal lower-limiting value θDs is not the previous hysteresis central value (HCUs−1) or more, the previous hysteresis central value is set as the present hysteresis central value (Step S124). In this manner, the hysteresis central value HCUs is calculated.
Thereafter, a steering judging section 115s which the hysteresis central value HCUs is inputted, judges whether the present hysteresis central value is coincident with the previous hysteresis central value (Step S130). In a case that the present hysteresis central value is coincident with the previous hysteresis central value, the steering holding signal HSU is outputted as the judging result (Step S131). In a case that the present hysteresis central value is not coincident with the previous hysteresis central value, the steering information STU is outputted as the judging result (Step S132).
The operation (the hysteresis process) of the column output-side angle signal θr1 is quite the same as that of the column input-side angle signal θs1. The operation (the hysteresis process) of the column output-side angle signal θr1 may be performed before or after that of the column input-side angle signal θs1.
The operation of
In an example of
In a method for detecting the steering state by using the conventional hysteresis filter with respect to the column input-side angle signal θs1 and the column output-side angle signal θr1 in a sensor system as shown in
In the second embodiment, as shown in
When the hysteresis width is narrowed from “A” (large) to “B” (small), it is necessary not to change the hysteresis central value due to a switch. In a case that a value between the input angle signals and the hysteresis central value is within a threshold, the hysteresis width is switched. To widen the hysteresis width from “B” (small) to “A” (large), since the change of the hysteresis central value is not treated by simply switching the hysteresis width, two hysteresis filters for the column input-side angle signal θs1 and the column output-side angle signal θr1 are prepared. In a case that respective hysteresis central values of the hysteresis width “A” and the hysteresis width “B” are changed, the hysteresis width is switched. In a case that the calculating of the hysteresis width “B” is always performed, the hysteresis central value of the hysteresis filter “A” is different from that of the hysteresis filter “B”. In this way, based on the result of the hysteresis filter “A”, only when the hysteresis trigger signal is ON, the calculating process and the judging of the hysteresis filter “B” are performed. Thereby, continuing to detect the change of the state, it is possible to switch the hysteresis width.
The column input-side angle signal θs1 of the handle side and the column output-side angle signal θr1 of the intermediate shaft side are inputted into the steering state judging section 140, and the steering state judging section 140 has a configuration as shown in
A hysteresis (B) central value HBs is outputted from the hysteresis filter (B) 142 which operates during the hysteresis trigger signal Tgs is inputted (ON), and is inputted into the steering information judging/steering holding judging section 143. A hysteresis (B) central value HBr is outputted from the hysteresis filter (B) 145 which operates during the hysteresis trigger signal Tgr is inputted (ON), and is inputted into the steering information judging/steering holding judging section 146.
As well, calculating initial input signals of the hysteresis filters (B) 142 and 145 are the hysteresis central values HAs and HAr from the hysteresis filters (A) 141 and 144, respectively.
Column input-side steering information STs and column input-side steering holding information HSs are outputted from the steering information judging/steering holding judging section 143, and column output-side steering information STr and column output-side steering holding information HSr are outputted from the steering information judging/steering holding judging section 146. The column input-side steering holding information HSs and the column output-side steering holding information HSr are inputted into an AND section 147 which judges a logical product condition. When both inputs are coincident, the steering holding signal HS is outputted from the AND section 147. A switching judging section comprises the steering information judging/steering holding judging sections 143 and 146, and the AND section 147.
The hysteresis filters (A) 141 and 144 are the same configuration. The column input-side angle signal θs1 will be described with reference to
The hysteresis filter (A) 144 into which the column output-side angle signal θr1 is inputted, is the same configuration of the hysteresis filter (A) 141.
The hysteresis filters (B) 142 and 145 are the same configuration. The column input-side angle signal θs1 will be described with reference to
The hysteresis filter (A) 145 into which the column output-side angle signal θr1 is inputted, is the same configuration of the hysteresis filter (A) 142.
The hysteresis widths are set by considering following conditions (a) and (b). The hysteresis widths have two widths “A” and “B”. Under satisfying the following conditions, the large hysteresis width “A” and the small hysteresis width “B” are set.
Further, as shown in
In such a configuration, an operating example of the steering state judging 140 will be described with reference to a flowchart of
At first, the hysteresis filter (A) 141 performs the filter process to the column input-side angle signal θs1 (Step S10). Next, the hysteresis filter (A) 144 performs the filter process to the column output-side angle signal θr1 (Step S20). This order may be changed. Thereafter, the switching judging of the hysteresis filter “A” or “B” is performed (Step S30), and the hysteresis trigger signal Tgs or Tgr from the hysteresis filter judging section 148 or 149 is judged ON or OFF (Step S40). In a case that the hysteresis trigger signal Tgs or Tgr is ON, the hysteresis filter (B) 142 performs the filter process to the column input-side angle signal θs1 (Step S50). Next, the hysteresis filter (B) 145 performs the filter process to the column output-side angle signal θr1 (Step S60). This order may be changed. Then, the process of the steering information judging (Step S70) and the process of the steering holding judging (Step S80) are performed. In a case that the hysteresis trigger signals Tgs and Tgr are OFF, the process of the steering information judging (Step S70) and the process of the steering holding judging (Step S80) are performed, and the steering process ends.
In short, the process of the hysteresis filter “A” performs to the filter process to the column input-side angle signal θs1 and the filter process to the column output-side angle signal θr1. Then, the judging of the hysteresis filter is performed. Based on the judging result, when the filter is switched to the hysteresis filter “B”, the process of the hysteresis filter “B” is performed, and the steering holding judging and the steering judging are performed using the hysteresis central values of the hysteresis filter “A” and the hysteresis filter “B”.
Next, the operations of the hysteresis filter judging sections 148 and 149 will be described with reference to the flowchart of
At first, it is judged whether the hysteresis filter is “A” (141) or “B” (142) (Step S100). When the hysteresis filter is “A”, it is judged whether the steering angle is in a range of the hysteresis width “B” from the hysteresis central value of the hysteresis “A” for a constant time (Step S101). In a case that the steering angle is in a range of the hysteresis width “B” for the constant time, it is judged that the hysteresis filter is “B” (Step S102), the hysteresis trigger signal Tgs is outputted (ON) (Step S103) and the process ends. In a case that the steering angle is not in a range of the hysteresis width “B” for the constant time, it is judged that the hysteresis filter is “A” (Step S104), the hysteresis trigger signal Tgs is OFF (Step S105) and the process ends.
When the hysteresis filter is “B” in judging of the above Step S100, it is judged whether the hysteresis central value of the hysteresis “A” is changed or not (Step S110). In a case that the hysteresis central value is changed, it is judged that the hysteresis filter is “A” (Step S111), the hysteresis trigger signal Tgs is OFF (Step S112) and the process ends. In a case that the hysteresis central value is not changed, it is judged that the hysteresis filter is “B” (Step S113), the hysteresis trigger signal Tgs is outputted (ON) (Step S114) and the process ends.
The operation of the hysteresis filter judging section 149 is also the same as that of the hysteresis filter judging section 148.
The operation of the hysteresis filters (A) 141 and 144 is Steps S111 to S112 and Steps S120 to S124 described in
In the detecting of the steering holding state, the central value of the hysteresis width (the hysteresis central value) is used. The initial value of the hysteresis central value is an average value of the steering angle upper-limiting value and the steering angle lower-limiting value, and the hysteresis central value is updated by the hysteresis filter process. The steering angle upper-limiting value and the steering angle lower-limiting value, which are set by the detected steering angle, are compared to the past value of the hysteresis central value (the previous hysteresis central value), and the update of the hysteresis central value is performed. In a case that the past value of the hysteresis central value (the hysteresis central past value) is larger than the steering angle upper-limiting value, or the hysteresis central past value is the steering angle lower-limiting value or less, the hysteresis central value is updated. In other cases, the hysteresis central value is not updated. When the hysteresis central value is not updated, it is judged that the provisional steering holding state (the provisional steering holding state) is occurred at that point. When all of the judging results (the provisional steering information), which plural steering sensors are detected to the steering angle, are the provisional steering holding state, it is detected that the steering holding state at that point. The detecting result of the steering holding state is utilized to a characteristic improvement of the current command value.
In the present invention, since the hysteresis characteristic is added to the steering angle signal, and the hysteresis width is existed in the detecting process of the steering holding state, the immediate detecting is possible without the filter process or the like even though a noise or the like is generated. Because the detecting process is performed by updating the hysteresis central value and using the plural judging results to the steering angle, few erroneously detecting has occurred, and the accurate detecting is possible.
The relationship of the above logical values “1” and “0” may be constructed by an inverse logical circuit.
In the above embodiments, the calculating process and the control are performed by using two angle informations of the column input-side and the column output-side. It is possible that an estimate value of the column output-side angle which is calculated from the column input-side angle, the steering torque and the spring rate of the torsion bar without providing with the column output-side angle detecting means, is used as an alternative of the column output-side angle. Or on the contrary, the column input-side angle may be estimated from the column output-side angle.
The column output-side angle may be estimated by utilizing a reduction ratio of a column reduction mechanism section from a motor-resolver angle, and the column input-side angle may be estimated from the steering torque and the spring rate of the torsion bar.
Further, for a simple mounting, it is possible that the column input-side angle is only used without utilizing the column output-side angle and the motor-resolver angle, and the calculating process and the control are performed. Or on the contrary, it is possible that the column output-side angle is only used without utilizing the column input-side angle, and the calculating process and the control are performed.
Furthermore, it is possible that using only the motor-resolver angle, which substitutes for the column output-side angle, estimates and is alternative of the column output-side angle from the reduction ratio of the column reduction mechanism section. Or it is possible that using only the motor rotational speed, which substitutes for the motor resolver angle, estimates and is alternative of a motor rotational angle from an integral value of the rotational speed.
As described above, a TS_IS angle θs outputted from the 20° rotor sensor 22 and a TS_OS angle θr outputted from the 40° rotor sensor 24 are inputted into the steering angle calculating section 50. The steering angle calculating section 50 calculates absolute angles and outputs the steering angles θs1 and θr1.
A first steering state judging section 310 comprises a first hysteresis width setting section 311, a first hysteresis central value calculating section 312, a first hysteresis central value changing detecting section 313 and a past value retaining section 314. The first hysteresis width setting section 311 adds a predetermined value to the steering angle θs1 or subtracts a predetermined value from the steering angle θs1, and calculates the steering angle upper-limiting value and the steering angle lower-limiting value. The first hysteresis central value calculating section 312 calculates the hysteresis central value from the steering angle upper-limiting value, the steering angle lower-limiting value and a hysteresis central past value which is retained at the past value retaining section 314. The calculated hysteresis central value is inputted into the past value retaining section 314 and the first hysteresis central value changing detecting section 313. The first hysteresis central value changing detecting section 313 compares the inputted hysteresis central value to the hysteresis central past value which is retained at the past value retaining section 314, judges the steering state and outputs provisional steering information. In similar to the first steering state judging section 310, the second steering state judging section 320 comprises a second hysteresis width setting section 321, a second hysteresis central value calculating section 322, a second hysteresis central value changing detecting section 323 and a past value retaining section 324, and performs the similar processes to the steering angle θr1.
The steering holding state detecting section 400 detects the steering holding state based on a provisional steering information which is outputted from the first steering state judging section 310 and the second steering state judging section 320.
In such a configuration, the operating example will be described with reference to flowcharts of
The steering angle calculating section 50 calculates the steering angle θs1 (Step S300), outputs the steering angle θs1 to the first hysteresis width setting section 311, calculates the steering angle θr1 (Step S301) and outputs the steering angle θr1 to the second hysteresis width setting section 321. The first steering state judging section 310 performs the first steering judging process using the steering angle θs1 (Step S302).
The first hysteresis width setting section 311 adds a predetermined value R1 (hereinafter referred to as a “first hysteresis width parameter”) to the steering angle θs1, and calculates the steering angle upper-limiting value θ11 (=θs1+R1) (Step S330). The first hysteresis width setting section 311 subtracts the first hysteresis width parameter R1 from the steering angle θs1, and calculates the steering angle lower-limiting value θ12 (=θs1−R1) (Step S331).
The steering angle upper-limiting value θ11 and the steering angle lower-limiting value θ12 are inputted into the first hysteresis central value calculating section 312. The first hysteresis central value calculating section 312 compares the steering angle upper-limiting value en to the hysteresis central past value θcp1 which is retained at the past value retaining section 314 (Step S332). When “θcp1>θ11”, the steering upper-limiting value θ11 is set as the hysteresis central value θc1 (Step S334). When “θcp1≦θ11”, the hysteresis central past value θcp1 is compared to the steering angle lower-limiting value θ12 (Step S333). When “θcp1≦θ12”, the steering lower-limiting value θ12 is set as the hysteresis central value θc1 (Step S335). When “θcp1>θ12”, the hysteresis central past value θcp1 is set as the hysteresis central value θc1 (Step S336).
In a case that the steering angle upper-limiting value θ11 and the steering angle lower-limiting value θ12 are data calculated from the initial steering angle θs1 which is detected at a time of starting the steering angle detecting, an average value of the steering angle upper-limiting value θ11 and the steering angle lower-limiting value θ12 (=(θ11+θ12)/2) is set as the hysteresis central value θc1 . In a case of the third embodiment, since “θ11=θs1+R1” and “θ12=θs1−R1”, the initial hysteresis central value θc1 is θs1.
The hysteresis central value θc1 is outputted to the first hysteresis central value changing detecting section 313 and the past value retaining section 314. The first hysteresis central value changing detecting section 313 compares the hysteresis central past value θcp1, which is retained at the past value retaining section 314, to the hysteresis central value θc1 (Step S337). In a case that the hysteresis central value θc1 is equal to the hysteresis central past value θcp1, provisional steering information Sj1 is outputted as “provisional steering holding state” (Step S338). In a case that the hysteresis central value θc1 is not equal to the hysteresis central past value θcp1, the provisional steering information Sj1 is outputted as “provisional steering state” (Step S339).
The second steering state judging section 320 performs the second steering judging process using the steering angle θr1 (Step S303). Since the second steering judging process is almost the same as the first steering judging process, the description is omitted. In calculating the steering angle value θ21 and the steering angle value θ22, a predetermined value R2 (hereinafter referred to as a “second hysteresis width parameter”) is used, and the steering angle value θ21 and the steering angle value θ22 calculate as “θ21=θr1+R2” and “θ22=θr1−R2”, respectively.
The provisional steering information Sj1 which is outputted from the first hysteresis central value changing detecting section 313 and the provisional steering information Sj2 which is outputted from the second hysteresis central value changing detecting section 323 are inputted into the steering holding state detecting section 400. The steering holding state detecting section 400 compares the provisional steering information Sj1 to the provisional steering information Sj2 (Step S310). In a case that the provisional steering information Sj1 and Sj2 are “provisional steering holding state”, the detecting result is set as “steering holding state” (Step S311). In a case other than the above case, the detecting result is set as “steering state” (Step S312).
An effect of detecting the steering holding state according to the present embodiment is described in comparison with a method for detecting the steering holding state using a conventional fixed threshold. Here, the operation of the first steering state judging section 310 is described. The detecting of the steering holding state is also performed by using the provisional steering information Sj2 which is the judging result of the second steering state judging section 320. Since the effect of the present invention is described in comparison with the conventional method, for the description being prevented from becoming redundant, the description is carried out as the provisional steering information Sj2 is the same as the provisional steering information Sj1. Then, when the provisional steering information Sj1 is “provisional steering holding state”, the detecting result is set as “steering holding state”. When the provisional steering information Sj1 is “provisional steering state”, the detecting result is set as “steering state”.
Prior to the description, a comparison of the hysteresis central past value θcp1 and the steering angle upper-limiting value θ11 (Step S332), and a comparison of the hysteresis central past value θcp1 and the steering angle lower-limiting value θ12 (Step S333), which the first hysteresis central value calculating section 312 performs, converts to Equation 1 using θ11=θs1+R1 and θ12=θs1−R1.
if θs1<θcp1−R1, then θc1=steering angle upper-limiting value,
if θcp1−R1<θs1<θcp1+R1, then θc1=θcp1,
if θcp1+R1<θs1, then θc1=steering angle lower-limiting value. [Equation 1]
That is, in a case that the steering angle θs1 (actual steering angle) outputted from the steering angle calculating section 50 is in a range of “θcp1−R1” (hereinafter referred to as a “past lower-limiting value”) to “θcp1+R1” (hereinafter referred to as a “past upper-limiting value”), the hysteresis central value θcp1 is not updated. In a case that the steering angle θs1 is not in a range of “θcp1−R1” to “θcp1+R1”, the hysteresis central value θcp1 is updated to the steering angle upper-limiting value or the steering angle lower-limiting value. When the hysteresis central value θcp1 is not updated, the first hysteresis central value changing detecting section 313 judges “provisional steering holding state”. When the hysteresis central value θcp1 is updated, the first hysteresis central value changing detecting section 313 judges “provisional steering state”. Summarizing the conditions and the results, the overall result is expressed by a following Equation 2.
if actual steering angle<past lower-limiting value, then hysteresis central value =steering angle upper-limiting value in “steering state”,
if past upper-limiting value<actual steering angle<past upper-limiting value, then hysteresis central value is not updated in “steering holding state”,
if past lower-limiting value<actual steering angle, then hysteresis central value=steering angle lower-limiting value in “steering state”.
At first, it is described about
At a time point t31, the hysteresis central past value is the actual steering angle at a time t30, and the past upper-limiting value and the past lower-limiting value are the steering angle upper-limiting value and the steering angle lower-limiting value at a time point t30. Then, since the actual steering angle at a time point t31 is larger than the past upper-limiting value, it is “steering state” at the time point t31 and the hysteresis central value is updated to the steering angle lower-limiting value at the time point t31.
At a time point t32, the hysteresis central past value is the steering angle lower-limiting value at the time point t31 . The past upper-limiting value is a value which adds the first hysteresis width parameter R1 to the hysteresis central past value, and the past lower-limiting value is a value which subtracts the first hysteresis width parameter R1 from the hysteresis central past value. Then, since the actual steering angle at the time point t32 is larger than the past upper-limiting value, it is also “steering state” at a time t32 and the hysteresis central value is updated to the steering angle lower-limiting value at the time point t32.
At time points t33 and t34, the circumstances are almost the same as the above case, it is also “steering state” and the hysteresis central value is updated to the steering angle lower-limiting value.
At a time point t35, the hysteresis central past value is the steering angle lower-limiting value at the time point t34. The past upper-limiting value is a value which adds the first hysteresis width parameter R1 to the hysteresis central past value, and the past lower-limiting value is a value which subtracts the first hysteresis width parameter R1 from the hysteresis central past value. Since the actual steering angle at the time point t35 is in a range of the past lower-limiting value to the past upper-limiting value, it is “steering holding state” at the time point t35 and the hysteresis central value is not updated. The almost same circumstances are continued for a time point t36 to a time point t40, it is “steering holding state” for these times and the hysteresis central value is not updated.
At a time point t41, the hysteresis central past value remains the steering angle lower-limiting value at the time point t34. The past upper-limiting value is a value which adds the first hysteresis width parameter R1 to the hysteresis central past value, and the past lower-limiting value is a value which subtracts the first hysteresis width parameter R1 from the hysteresis central past value. Since the actual steering angle at the time point t41 is smaller than the past lower-limiting value, it is “steering state” at the time point t41 and the hysteresis central value is updated to the steering angle upper-limiting value. After a time point t42, because the same circumstances are continued, it is “steering state” and the hysteresis central value is updated to the steering angle upper-limiting value.
In this way, according to the present embodiment, it is judged “steering holding state” from the time point t35 to the time point t40, it is judged “steering state” for a time other than the time point t35 to the time point t40 and then it can be accurately detected in the steering holding state. In
On the other hand, in a method for detecting the steering holding state using a fixed threshold, it cannot be accurately detected in the steering holding. For example, in a case that the threshold is set to a difference of the actual steering angle (the absolute value), the threshold is set as values which are denoted by a broken line of
Next,
At a time t31, the hysteresis central past value is the actual angle at a time t30. The past upper-limiting value and the past lower-limiting value at a time t31 are the steering angle upper-limiting value and the steering angle lower-limiting value at the time point t30. Since the actual steering angle at the time point t31 is between the past lower-limiting value and the past upper-limiting value, it is “steering holding state” at a time t31 and the hysteresis central value is not updated.
At the time point t32, the hysteresis central past value remains the steering angle lower-limiting value at the time point t30. The past upper-limiting value is a value which adds the first hysteresis width parameter R1 to the hysteresis central past value, and the past lower-limiting value is a value which subtracts the first hysteresis width parameter R1 from the hysteresis central past value. Since the actual steering angle at the time point t32 is larger than the past upper-limiting value, it is “steering state” at a time t32 and the hysteresis central value is updated to the steering angle lower-limiting value at the time point t32. The almost same circumstances are continued for the time point t33 to the time point t35, it is “steering state” for these times and the hysteresis central value is updated to the steering angle lower-limiting value.
At the time point t36, the hysteresis central past value is the steering angle lower-limiting value at the time point t35. The past upper-limiting value is a value which adds the first hysteresis width parameter R1 to the hysteresis central past value, and the past lower-limiting value is a value which subtracts the first hysteresis width parameter R1 from the hysteresis central past value. Since the actual steering angle at a time point t36 is between the past lower-limiting value and the past upper-limiting value, it is “steering holding state” at a time t36, and the hysteresis central value is not updated. The almost same circumstances are continued for a time point t37 to a time point t39, it is “steering holding state” for this duration and the hysteresis central value is not updated.
At the time point t40, the hysteresis central past value remains the steering angle lower-limiting value at the time point t35. The past upper-limiting value is a value which adds the first hysteresis width parameter R1 to the hysteresis central past value, and the past lower-limiting value is a value which subtracts the first hysteresis width parameter R1 from the hysteresis central past value. Since the actual steering angle at the time point t40 is larger than the past upper-limiting value, it is “steering state” at a time t40 and the hysteresis central value is updated to the steering angle lower-limiting value. After a time t41, because the same circumstances are continued, it is “steering state” and the hysteresis central value is updated to the steering angle lower-limiting value.
In this way, according to the present invention, it is judged “steering holding state” from the time point t36 to the time point t39, and then it can be accurately judged “steering state” for a time other than the time point t36 to the time point t39. In
On the other hand, in a method for detecting the steering holding state using a fixed threshold, it cannot be accurately detected in the steering holding. In a case that the threshold is set to a difference of the actual steering angle (absolute value), as well as in a case of
In the third embodiment, the apparatus comprises two steering state judging sections. The two steering state judging sections can be combined to one steering state judging section and the one steering state judging section may perform the process to the steering angles θs1 and θr1. The steering angles which are used for detecting the steering holding state may increase. Further, although the same predetermined value is used in calculating of the steering angle upper-limiting value and the steering angle lower-limiting value, different predetermined values may be used. The first hysteresis width parameter R1 may be the same as the second hysteresis width parameter R2. In a case that the hysteresis central value is the same as the hysteresis central past value, the provisional steering information is set as “provisional steering holding state”. Even in a case that a difference between the hysteresis central value and the hysteresis central past value is slight, the provisional steering information may be set as “provisional steering holding state”.
Number | Date | Country | Kind |
---|---|---|---|
2015-018527 | Feb 2015 | JP | national |
2015-028002 | Feb 2015 | JP | national |
2015-028324 | Feb 2015 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2016/053005 | 2/2/2016 | WO | 00 |