JP4183111B2 - Shift-by-wire system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a shift-by-wire system in which a shift range of an automatic transmission is selected by motor drive based on electric control.
[0002]
[Prior art]
Conventionally, as a shift-by-wire system, for example, the one described in JP-A-5-256357 is known. In the shift-by-wire system described in this publication, a range switching valve of an automatic transmission is switched by a motor driven based on electric control in accordance with a shift switch signal operated by a driver. A position sensor capable of detecting the operation amount of the range switching valve is provided, and shift control is performed by matching with the shift switch signal based on the detection signal from the position sensor.
[0003]
At this time, the shift switch has two switches in the same range, and stable shift control is achieved by increasing the reliability of the shift switch.
[0004]
[Problems to be solved by the invention]
However, in the conventional shift-by-wire system, there is no means for detecting whether or not the signal from the position sensor has failed. Even if the reliability of the shift switch signal is ensured, the shift switch signal and the position sensor Since shift control is performed by matching with the detection signal, if the reliability of the position sensor is low, there is a problem that the reliability of the overall shift control is lowered. This problem is not limited to sensors. For example, a CPU for arithmetic processing or the like has a similar problem with respect to reliability.
[0005]
The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is necessary for shift control in a shift-by-wire system in which selection of a shift position of an automatic transmission is performed by motor drive based on electric control. An object of the present invention is to provide a shift-by-wire system capable of realizing shift control with high safety by increasing signal reliability.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, there is provided a shift switch which is operated by a driver and outputs a switch signal indicating a shift position corresponding to each range such as a parking range, a reverse range, a neutral range and a drive range. A shift actuator that is provided in the automatic transmission and drives a manual valve, a parking rod, and the like; a potentiometer that detects the drive amount of the shift actuator; and a preset value from the current shift position based on the shift switch signal A shift actuator target drive amount calculation unit for calculating a target drive amount of the shift actuator up to a shift position target value corresponding to the range indicated by the switch signal, and driving the shift actuator based on the calculated target drive amount A shift actuator driving signal output unit for outputting a signal, and a shift control unit that adjusts the shift switch and the potentiometer value by feedback control based on the shift switch signal and the potentiometer value. In the system, the shift switch comprises a first shift switch and a second shift switch that output the same signal, the potentiometer comprises a first potentiometer and a second potentiometer that output the same signal, and the shift control means In addition, it is determined whether or not the signals of the first and second shift switches match, and if they do not match, the signals of the shift switch failure detection unit that determines a failure and the signals of the first and second potentiometers match. Judge whether or not A potentiometer failure detection unit determines that failure if not, the provided, further comprising a shift control means, even the driver is turned OFF the power, provided the shift-by-wire system power supply can be secured a shut-relay, operating When a person turns off the power, the power is secured by the self-shut relay, it is determined whether the shift switch signal and the potentiometer signal are matched, and if they are matched, the power is turned off by the self-shut relay, If not matched, a power ON / OFF command output unit for turning off the power by a self-shut relay after matching is achieved by outputting a drive signal to the shift actuator .
[0007]
In invention of Claim 2, in the shift-by-wire system of Claim 1,
The shift control means is provided with an input signal fail control unit that outputs a torque down command to the engine control unit when a failure is detected from the shift switch fail detection unit or the potentiometer fail detection unit. A featured shift-by-wire system.
[0008]
In invention of Claim 3, in the shift-by-wire system of Claim 1 or 2,
By providing a shift lock mechanism that locks the shift switch to prohibit the driver from operating the shift switch,
The shift control means comprises a first shift control unit and a second shift control unit that perform the same control calculation process,
The shift control means is provided with a shift control failure detection unit that determines whether or not the first shift control unit and the second shift control unit are performing the same control calculation process, and if they do not match, determines a failure.
When a failure is detected from the shift control failure detection unit, a shift lock command is output to the shift lock mechanism and at least one of the first shift control unit and the second shift control unit cannot be operated. A shift control failure control unit is provided.
[0010]
According to a fourth aspect of the present invention, in the shift-by-wire system according to any one of the first to third aspects, an inhibitor switch that outputs a range signal indicating the position of the manual valve is provided, and the shift control means is connected to the shift switch signal. It is characterized in that it is a means for matching with the potentiometer signal and for matching with the inhibitor switch signal.
[0011]
Operation and effect of the invention
In the shift-by-wire system according to the first aspect, the shift switch and the potentiometer are a double system that outputs the same signal. The shift control means is provided with a shift switch failure detection unit and a potentiometer failure detection unit, and always monitors whether the input signal is failing by determining whether the input signals always match. be able to. As a result, shift control can be performed based on a highly reliable input signal, and a stable shift-by-wire system can be provided.
The shift control means is provided with a self-shut relay. When the driver turns off the power supply, the power supply ON / OFF command output unit secures the power supply by the self-shut relay, determines whether the shift switch signal and the potentiometer signal are matched, The power is turned off by the self-shut relay, and if not matched, a drive signal is output to the shift actuator, and after matching is achieved, the power is turned off by the self-shut relay. In other words, if the driver turns off the power immediately after operating the shift switch, if the power of the shift-by-wire system is turned off, the shift switch signal and the actual shift actuator movement (potentiometer signal) cannot be matched. There is a case. Therefore, the shift position indicated by the shift switch and the actual shift position can always be matched by securing the power supply by the self-shut relay and turning off the power supply after matching the shift switch signal and the potentiometer signal.
[0012]
In the shift-by-wire system according to claim 2, when a failure is detected from the shift switch fail detecting unit or the potentiometer fail detecting unit, an input for outputting a torque down command to the engine control unit is provided to the shift control means. A signal fail control unit is provided. Therefore, when a failure of the input signal is detected, a torque down request is output to the engine, so that even if the accelerator is stepped on, the vehicle does not start suddenly and safety can be ensured. Moreover, since the vehicle can travel at least at a low speed, the vehicle can be moved a short distance from the failure location such as bringing the vehicle close to the road shoulder.
[0013]
In the shift-by-wire system according to the third aspect, a shift lock mechanism is provided, and the shift control means is composed of a first shift control unit and a second shift control unit that perform the same control arithmetic processing. Then, in the shift control failure detection unit provided in the shift control means, it is determined whether or not the first shift control unit and the second shift control unit are performing the same control calculation process, and if they do not match, it is determined as a failure, A shift lock command is output to the shift lock mechanism, and at least one of the first shift control unit and the second shift control unit is disabled in the shift control fail control unit. As a result, even if the shift control unit that performs the control calculation process runs out of control, the shift operation is prohibited by the shift lock mechanism, the shift-by-wire system can be stopped, and safety can be ensured. it can.
[0015]
The shift-by-wire system according to claim 4 is provided with an inhibitor switch that outputs a range signal indicating the position of the manual valve, and the shift control means matches the shift switch signal with the potentiometer signal, and the inhibitor switch Matching with the signal is achieved. In other words, both the potentiometer and the inhibitor switch are linked to the movement of the manual valve, and the movements of the two are always matched. Therefore, it becomes possible to detect the failure of the potentiometer signal and the inhibitor switch signal, and the reliability of the input signal is further improved. Can be increased.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment for realizing a shift-by-wire system according to the present invention will be described.
[0017]
First, the configuration will be described.
FIG. 1 is an overall configuration diagram illustrating a shift-by-wire system according to an embodiment. In the figure, 1 is an indicator showing a shift selection position, 2 is a fail lamp for notifying the driver of an abnormality, 3 is a key interlock solenoid, 4 is a shift switch for selecting a shift position, 5 is a shift lock mechanism, and 6 is an ignition switch. It is.
[0018]
20 is a shift control unit, 40 is a CVT control unit for controlling the automatic transmission 60, 50 is an engine control unit, 60 is an automatic transmission, 61 is a transmission mechanism, 62 is selected by the automatic transmission. This is an inhibitor switch that outputs a range signal. In the present embodiment, the belt-type continuously variable transmission is mounted on the transmission mechanism 61, but even a stepped transmission can be used without any problem. 30 is a shift actuator provided in the vicinity of the inhibitor switch 62, 31 is a main motor, and 32 is a sub motor.
[0019]
FIG. 2 is an overall system diagram illustrating the shift-by-wire system according to the embodiment. The shift control unit 20 is provided with a main CPU 21a and a sub CPU 22a, and these CPUs 21a and 22a are configured to always monitor each other and detect an abnormality. The CPUs 21a and 22a have a self-destruct mechanism that stops their operation when an abnormality is detected, and safety is ensured by preventing the CPU 21a and 22a from running away from the driver's intention. Further, a main driver 21 that supplies the drive voltage calculated by the main and sub CPUs 21 a and 22 a to the main motor 31 and a sub driver 22 that supplies the sub motor 32 are provided. Further, the shift control unit 20 receives a signal from the CVT control unit 40 that performs the shift control of the transmission mechanism 61 and outputs a signal to the engine control unit 50.
[0020]
The shift actuator 30 is connected to the gear mechanism 33 driven by the main motor 31 or the sub motor 32, the temperature sensor 35 for detecting the temperature of the main motor 31, and the gear mechanism 33, and the shift range is controlled via the inhibitor switch 62. A potentiometer 34 for detecting the rotation angle of the control shaft 36 is provided, and is driven based on a signal from the shift control unit 20. The shift switch 4 includes a first shift switch 4 a that outputs a signal to the shift control unit 20 and a second shift switch 4 b, and the potentiometer 34 also outputs a first signal to the shift control unit 20. It consists of a potentiometer 34a and a second potentiometer 34b.
[0021]
The power supply to the shift control unit 20 is supplied from the power supply 24 via the self shut relay 23. Here, the self-shut relay 23 will be described. FIG. 4 is a schematic diagram showing a system of the self-shut relay 23. The power-on signal output from the ignition switch 6 is input to the power supply 24 and an ON / OFF command output unit 25 provided in the shift control unit 20. At this time, the relay switch 27 is turned ON, and power is supplied to the shift control unit 20, and an ON command is output from the ON / OFF command output unit 25 to the virtual switch 26, and the power of the power source 24 is secured. At this time, even if the ignition switch 6 is turned off, the power supply of the shift control unit 20 is determined by a command from the ON / OFF command output unit 25 to the virtual switch 26.
[0022]
Next, the operation will be described.
FIG. 3 is a flow chart showing the flow of shift control processing when a shift change is executed by the shift control unit 20, and each step will be described below.
[0023]
In step 101, it is determined whether or not the voltage V is equal to or higher than a predetermined voltage value V1, and if it is equal to or higher than the predetermined voltage V1, the process proceeds to step 101b, and if it is lower than the predetermined voltage V1, the process proceeds to step 102.
[0024]
In step 102, the shift lock mechanism 5 is turned on.
[0025]
In step 103, power is secured by a self-shut relay.
[0026]
In step 104, the shift lock mechanism 5 is turned off.
[0027]
In step 105, the signals of the first shift switch 4a and the second shift switch 4b are read.
[0028]
In step 106, it is determined whether or not the signals of the first shift switch 4a and the second shift switch 4b match. If they match, the process proceeds to step 105. If they do not match, the process proceeds to step 118.
[0029]
In step 107, the signals of the first potentiometer 34a and the second potentiometer 34b are read.
[0030]
In step 108, it is determined whether or not the signals of the first potentiometer value and the second potentiometer value match. If they match, the process proceeds to step 107. If they do not match, the process proceeds to step 120.
[0031]
In step 109, the signal of the shift switch 4 is read.
[0032]
In step 110, it is determined whether or not the target position has been updated. If updated, the process proceeds to step 111, and if not updated, the process proceeds to step 114.
[0033]
In step 111, a target position is set.
[0034]
In step 112, the motor drive amount is calculated.
[0035]
In step 113, a motor drive signal is output.
[0036]
In step 114, it is determined whether the shift switch signal, the potentiometer signal, and the inhibitor switch signal match. If they match, the process proceeds to step 115, and if they do not match, the process proceeds to step 118.
[0037]
In step 115, the motor drive signal is stopped.
[0038]
In step 116, it is determined whether or not the voltage V is equal to or higher than a predetermined voltage value V1. If the voltage V is equal to or higher than the predetermined voltage V1, this control is terminated, and if it is lower than the predetermined voltage V1, the process proceeds to step 117.
[0039]
In step 117, the self-shut relay is turned off.
[0040]
In step 118, 1 is added to the previous counter value N0 as the counter value N.
[0041]
In step 119, it is determined whether or not the counter value N is equal to or larger than the predetermined counter value N1, and if it is equal to or larger than the predetermined counter value N1, the process proceeds to step 120. If it is smaller than the predetermined counter value N1, the process proceeds to step 105.
[0042]
In step 120, a warning lamp is turned on, a warning buzzer, torque down control, a shift lock solenoid ON, etc. are performed as fail control.
[0043]
[Action]
It is determined whether or not the voltage V is equal to or higher than a predetermined voltage value V1, and if it is less than the predetermined voltage V1, the power is secured by the self shut relay 23 and the shift lock solenoid 5 is turned on. That is, if the driver stops the engine immediately after the shift operation and turns off the power, if the operation of the shift actuator 30 corresponding to the position indicated by the shift switch 4 is not ensured, the shift switch 4 and the actual switch A shift occurs in the shift position. Therefore, a power source is secured in order to match the shift switch 4 with the actual shift position. Further, by turning on the shift lock solenoid 5, the operation of the shift switch 4 is prohibited after the driver turns off the power, thereby preventing the position indicated by the shift switch 4 from being inconsistent with the actual shift position. Yes.
[0044]
In step 105 and step 106, the signals of the first shift switch 4a and the second shift switch 4b are read, and it is determined whether or not the signals of the first shift switch 4a and the second shift switch 4b match. That is, the reliability of the input signal to the shift control unit 20 can be increased by making the shift switch 4 a double system. At this time, if the signals do not match, the process proceeds to fail control in step 120. Similarly, in order to increase the reliability of the potentiometer value, also in steps 107 and 108, the signals of the first potentiometer 34a and the second potentiometer 34b are read, and the signals of the first potentiometer value and the second potentiometer value match. Determine whether or not.
[0045]
Next, the signal of the shift switch 4 is read to determine whether the target position has been updated. If the target position has been updated, the target position is set, the motor drive amount is calculated, and the motor drive signal is output. In step 114, it is determined whether the shift switch signal, the potentiometer signal, and the inhibitor switch signal match. Thus, if the shift switch signal and the potentiometer signal match, it can be determined not only that the shift has been completed, but also whether the potentiometer value and the inhibitor switch signal match, thereby determining whether the potentiometer 34 or the inhibitor switch 62 Fail can be detected. This is because the potentiometer 34 and the inhibitor switch 62 are both connected to the control shaft 36 and therefore always show the same movement.
[0046]
Until the match of each signal is confirmed, 1 is added to the previous counter value N0 as the counter value N to determine whether the counter value N is equal to or greater than the predetermined counter value N1. For example, it is determined that a failure has occurred and the fail control is performed. If it is less than the predetermined counter value N1, the shift actuator 30 is driven until the matching of each signal is confirmed.
[0047]
When matching of the shift switch signal, the potentiometer signal, and the inhibitor switch signal is confirmed, the motor drive signal is stopped and it is determined whether or not the voltage V is equal to or higher than a predetermined voltage value V1. If the voltage is equal to or higher than the predetermined voltage V1, the control is terminated. If the voltage is lower than the predetermined voltage V1, the process proceeds to step 117, and the power supply to the shift control unit 20 is cut off by turning off the self-shut relay 23. That is, if the voltage is less than the predetermined voltage V1 in step 101, the power supply is secured by the cell shut relay 23, and it is necessary to turn off the self shut relay 23.
[0048]
In step 120, fail control is performed. As the fail control, a warning light is turned on, a warning buzzer, torque down control, a shift switch lock by a shift lock solenoid ON, and the like are performed. Here, the torque down control will be described. When a failure is detected, a torque down request is output to the engine control unit 50, so that even if the accelerator is stepped on, the vehicle does not start suddenly and safety can be ensured. Further, in this embodiment, depending on the type of failure, it is possible to run at least at a low speed, so that it is possible to move a little distance from the place of failure such as bringing the vehicle to the road shoulder.
[0049]
As described above, in the shift-by-wire system of the present embodiment, the shift switch 4 and the potentiometer 34 are a double system that outputs the same signal. In step 106 and step 108, it is possible to always monitor whether or not the input signal has failed by determining whether or not the input signals always match. As a result, shift control can be performed based on a highly reliable input signal, and a stable shift-by-wire system can be provided.
[0050]
When a failure is detected, a torque down command is output to the engine control unit 50 in step 120. Therefore, by outputting a torque down request to the engine, even if the accelerator is stepped on, the vehicle does not start suddenly and safety can be ensured. Moreover, since the vehicle can travel at least at a low speed, the vehicle can be moved a short distance from the failure location such as bringing the vehicle close to the road shoulder.
[0051]
Further, a shift lock solenoid 5 is provided, and a main CPU 21a and a sub CPU 22a are provided. The main CPU 21a and the sub CPU 22a are mutually monitored to determine whether they are performing the same control calculation processing. A shift lock command is output to the shift lock solenoid 5, and at least one of the main CPU 21a and the sub CPU 22a is disabled. As a result, even if the CPU that performs the control calculation process runs out of control, the shift operation is prohibited by the shift lock solenoid 5, and the shift-by-wire system can be stopped, thereby ensuring safety. .
[0052]
The shift control unit 20 is provided with a self-shut relay 23. That is, if the power is turned off immediately after the driver operates the shift switch 4, if the power of the shift-by-wire system is turned off, the shift switch signal and the actual movement of the shift actuator (potentiometer signal) can be matched. There may not be. Therefore, in step 103, the power is secured by the self-shut relay 23, and in step 114, the shift switch signal, the potentiometer signal, and the inhibitor switch signal are matched, and then the power is turned off. The actual shift position can always be matched.
[0053]
In step 114, the shift switch signal, the potentiometer signal, and the inhibitor switch signal are matched. In other words, both the potentiometer and the inhibitor switch are linked to the movement of the manual valve, and the movements of the two are always matched. Therefore, it becomes possible to detect the failure of the potentiometer signal and the inhibitor switch signal, and the reliability of the input signal is further improved. Can be increased.
[0054]
(Other embodiments)
As described above, the shift-by-wire system of the present invention has been described based on the embodiments, but the specific configuration is not limited to these embodiments, and is described in each claim of the claims. Design changes and additions are allowed without departing from the scope of the present invention.
[Brief description of the drawings]
FIG. 1 is an overall system diagram showing a shift-by-wire system according to an embodiment.
FIG. 2 is a control system diagram of the shift-by-wire system according to the embodiment.
FIG. 3 is a schematic diagram illustrating a self-shut relay in the shift-by-wire system according to the embodiment.
FIG. 4 is a flowchart showing shift control in the shift-by-wire system according to the embodiment.
[Explanation of symbols]
1 Indicator 2 Fail lamp 3 Key interlock solenoid 4 Shift switch 5 Shift lock mechanism 6 Ignition switch 20 Shift control unit 21 Main driver 21a Main CPU
22 Sub-driver 22a Sub-CPU
23 Self-Shut Relay 24 Power Supply 25 ON / OFF Command Output Unit 26 Virtual Switch 27 Relay Switch 30 Shift Actuator 31 Main Motor 31a Worm 32 Sub Motor 32a Worm 33 Gear Mechanism 34 Angle Sensor 35 Temperature Sensor 36 Control Shaft 60 Automatic Transmission 61 Shift Mechanism Part 62 Inhibitor switch 63 CVT control unit 64 Engine control unit

Claims (4)

A shift switch that is operated by a driver and outputs a switch signal indicating a shift position corresponding to each range such as a parking range, a reverse range, a neutral range, and a drive range;
A shift actuator provided in an automatic transmission, for driving a manual valve, a parking rod, and the like;
A potentiometer for detecting the drive amount of the shift actuator, and a target drive of the shift actuator from a current shift position to a shift position target value corresponding to a range indicated by the switch signal set in advance based on the shift switch signal A shift actuator target drive amount calculation unit that calculates a quantity; a shift actuator drive signal output unit that outputs a drive signal to the shift actuator based on the calculated target drive quantity; and the shift switch signal and the potentiometer value Shift control means for matching the shift switch and the potentiometer value by feedback control based on:
In a shift-by-wire system with
The shift switch comprises a first shift switch and a second shift switch that output the same signal,
The potentiometer includes a first potentiometer and a second potentiometer that output the same signal,
The shift control means determines whether or not the signals of the first and second shift switches match, and if they do not match, determines a failure and a signal of the first and second potentiometers. And a potentiometer failure detection unit that determines whether or not a failure is detected ,
Further, the shift control means is provided with a self-shut relay capable of securing the power of the shift-by-wire system even if the driver turns off the power, and when the driver turns off the power, the self-shut relay supplies the power. To determine whether or not the shift switch signal and the potentiometer signal are matched, and if matched, turn off the power by a self-shut relay, and if not matched, output a drive signal to the shift actuator. A shift-by-wire system comprising a power ON / OFF command output unit for turning off the power by a self-shut relay after matching is achieved. The shift-by-wire system according to claim 1,
The shift control means is provided with an input signal fail control unit that outputs a torque down command to the engine control unit when a failure is detected from the shift switch fail detection unit or the potentiometer fail detection unit. A featured shift-by-wire system. The shift-by-wire system according to claim 1 or 2,
By providing a shift lock mechanism that locks the shift switch to prohibit the driver from operating the shift switch,
The shift control means comprises a first shift control section and a second shift control section that perform the same control calculation process, and the first shift control section and the second shift control section are included in the shift control means. A shift control failure detection unit that determines whether or not processing is performed and determines that a failure occurs if they do not match,
When a failure is detected from the shift control failure detection unit outputs the shift lock command to the shift lock mechanism is inoperative the control section of the first shift controller and the second shift control unit A shift-by-wire system comprising a shift control / fail control unit. The shift-by-wire system according to claims 1 to 3 ,
An inhibitor switch that outputs a range signal indicating the position of the manual valve is provided,
A shift-by-wire system characterized in that the shift control means is means for matching the shift switch signal and the potentiometer signal and for matching the inhibitor switch signal.

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