JP2005308024A - Select assist device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a select assist device for an automatic transmission enabling range switch operation at a time of failure by a mechanical connection of a selection lever and a range position switch device, capable of enlarging degree of freedom of lay out by miniaturizing the selection lever and providing selection lever operation force characteristics in response to demand. <P>SOLUTION: This device is provided with an operating force determination part 46 determining whether operating force is applied to a select lever 2, LPF 471 detecting temperature drift quantity of a torque sensor, a second input operation calculation part 47 calculating a second input operation force which is temperature drift quantity and keeping the second input operation force at a value before calculation when it is determined that operation force is applied, and a third input operation force calculation part 48 calculating a third input operation force subtracting the second input operation force from a first input operation force. A control unit 22 uses the third input operation force as an input operation force. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to a technical field of a selection assist device for an automatic transmission that assists a driver's select lever operating force in a vehicle equipped with the automatic transmission.

  Conventionally, a select lever of an automatic transmission is mechanically connected to a manual valve of the automatic transmission via an operating force transmission means such as a rod or a cable. The operating force of the driver input to the select lever is transmitted to the manual valve via the operating force transmission means, and the range position is switched according to the operation amount (see, for example, Patent Document 1).

On the other hand, what uses what is called shift-by-wire technique in which the select lever and the manual valve are electrically connected is known. In this prior art, an actuator that operates a manual valve is provided, and the range position is switched by driving the actuator by changing the rotation operation of the select lever into an electric signal (see, for example, Patent Document 2).
JP-A-9-323559 JP 2003-97694 A

  When the select lever is operated, a mechanical operating reaction force such as friction of the operating force transmission means, resistance of detent, etc. is generated, and thus a large operating force is required. Therefore, in order to reduce the necessary operating force of the driver, it is necessary to set the length of the select lever to a length that can obtain a sufficient lever force.

  Therefore, the former of the above prior arts has a problem that the shape becomes large due to the length of the select lever, so that there are many restrictions on the installation place and the degree of freedom in layout in the vehicle interior is low.

  On the other hand, in the latter, the selection lever can be designed shorter by adopting the actuator, and the degree of freedom in layout becomes higher than that in the former. However, since the select lever and the manual valve are not mechanically connected, the range cannot be switched during a failure.

  The present invention has been made paying attention to the above problems, and its object is to enable range switching by mechanically connecting the select lever and the range position switching device, while also allowing freedom in layout by downsizing the select lever. It is an object of the present invention to provide a selection assist device for an automatic transmission that can achieve a widening range of the automatic transmission and obtain a select lever operating force characteristic according to demand.

  In order to achieve the above-mentioned object, in the present invention, an input operation force detecting means for detecting an input operation force to a select lever connected to a range position switching device of an automatic transmission as a first input operation force, and the select lever Assisting the assist actuator based on the detected input operation force and the operation position, an operation position detection means for detecting the operation position of the driver, an assist actuator for outputting an assist force for assisting the driver's operation force to the select lever A selection assist device for an automatic transmission having an assist force control means for outputting a control command for changing a force, and an operation force presence / absence determination means for determining that an operation force is applied to the select lever; Characteristic change detecting means for detecting a characteristic change amount of the input operating force detecting means; and When the second input operating force that is the characteristic change detected by the sex change detecting means is calculated and the operating force presence / absence determining means determines that the operating force is applied, the second input operating force is calculated before the calculation. A second input operating force calculating means for holding the value, and a third input operating force calculating means for calculating a third input operating force obtained by subtracting the second input operating force from the first input operating force. The control means uses a third input operation force as the input operation force.

According to the first aspect of the present invention, while maintaining the mechanical connection between the select lever and the range position switching device, the assist lever operating force of the driver is assisted by the assist actuator, so that the range can be switched at the time of failure and the size of the select lever can be reduced. The layout flexibility can be expanded by making it easier.
Further, the third input operation force calculated from the first input operation force and the second input operation force is used in the assist force control means, and the second input operation force calculation means applies the operation force in the operation force presence / absence determination means. If it is determined that the second input operation force is maintained, the second input operation force is held at the value before the calculation. Therefore, even when the operation force is applied, it is possible to suppress a decrease in detection accuracy of the input operation force.

  Hereinafter, an embodiment for realizing a selection assist device for an automatic transmission according to claims 1 and 2 will be described based on examples.

First, the configuration will be described.
FIG. 1 is a side view showing a configuration of an automatic transmission apparatus according to a first embodiment, and FIG. 2 is a perspective view of a main part showing a detailed structure of an assist actuator.

  The automatic transmission apparatus according to the first embodiment includes a selection mechanism unit 1, a control cable 8, an assist actuator 9, a control cable 18, an automatic transmission 19, and a control unit (assist force control means) 22 as main components. It is said.

  The selection mechanism unit 1 has a selection lever 2 that is operated by a driver, and is provided, for example, in a center cluster 3 beside the driver's seat. At the upper end of the select lever 2, a select knob 4 is attached for the driver to hold during the select operation. The select lever 2 is rotated about the fulcrum shaft 5 and is set to 100 mm, which is 250 mm shorter than a conventional general select lever.

A push-pull control cable 8 is connected to the lower end of the select lever 2 via a select lever joint 7. The control cable 8 is rotatably connected to the input lever 10 of the assist actuator 9 via the input lever joint 11. That is, the rotational movement of the select lever 2 is converted into a linear movement, and the operating force generated by the operation of the select lever 2 is transmitted to the input lever 10.
In addition, the select knob 4 of the select lever 2 is provided with an infrared sensor 49 that detects that the operator approaches his / her hand for operation.

  The input lever 10 is connected to an output lever 13 via an output shaft 12 that is rotatably provided. The output shaft 12 is provided with a worm gear 14 that meshes with a motor output shaft 16 of an electric motor 15 having a speed reduction mechanism.

  A push-pull control cable 18 is connected to the output lever 13 via an output lever joint 17. The control cable 18 is connected to the control arm 20 of the automatic transmission 19. That is, the rotational movement of the output lever 13 is converted into a linear movement by the control cable 18, and the combined force of the driver's operating force and the driving force of the electric motor 15 is transmitted to the control arm 20 of the automatic transmission 19.

  The output shaft 12 is provided with a torque sensor (input operation force detection means) 21 that detects distortion (twist) generated between the input lever 10 and the worm gear 14. The operation force signal detected by the torque sensor 21 is amplified by an amplification amplifier (not shown) and transmitted to the control unit 22 via the wire harness 23. Based on the detection signal of the torque sensor 21, the operation force in the select lever operation can be estimated.

  A contact 24 for position detection is attached and fixed to the worm gear 14. The contactor 24 rotates integrally with the worm gear 14 and makes electrical contact with a carbon resistor printed on a substrate (not shown), thereby outputting a voltage signal corresponding to the stroke angle of the select lever 2 to the control unit 22. . The contactor 24 and the carbon resistance constitute a potentiometer (operation position detecting means) 25.

  The potentiometer 25 detects the stroke angle of the select lever 2 at any time with the angle when the select lever 2 is stopped at the P range position as the base point angle.

  The control unit 22 sets a target assist force based on the detected stroke angle of the select lever 2 and the operation force of the driver, and performs PWM control on the output of the electric motor 15.

FIG. 3 shows a control block diagram of the control unit 22.
The change in the stroke of the select lever 2 that has been subjected to the range switching operation in the select mechanism unit 1 is input to the potentiometer 25 of the assist actuator 9 via the control cable 8. The potentiometer 25 detects a stroke angle corresponding to the operation amount of the select lever 2 and outputs it to the control unit 22 as a stroke angle signal.

  Further, the operating force of the select lever 2 is input to the torque sensor 21 of the assist actuator 9 via the control cable 8. The torque sensor 21 detects the operation force of the select lever 2 and outputs it to the control unit 22 as an operation force signal.

  The position / operation start / direction discriminating block 33 determines the current stroke angle of the select lever 2 based on the stroke angle signal. Further, the operation start, the operation direction, the operation speed, and the operation acceleration of the select lever 2 are determined from the stroke angle signal, the differential value of the stroke angle signal, and the operation force signal, and the determination results are obtained from the FF compensation table 43 and the target table block 34. Output to the motor drive control block 45.

  In the target table block 34, the target operation reaction force corresponding to the stroke angle of the select lever 2 is calculated from the stroke angle signal and the operation direction of the select lever 2 obtained by the position / operation start / direction determination block 33. It is output to the adder 35.

  Here, since the target operation reaction force varies depending on the stroke angle of the select lever 2, the target operation reaction force for each stroke angle is stored in a table in the target table block 34.

  The adder 35 calculates a deviation between the operation force signal and the target operation reaction force, and outputs the calculation result to the FB control unit 36.

  The FB control unit 36 includes a multiplier 37, an adder 38, a multiplier 39, and an integrator 40. The multiplier 37 outputs a value obtained by multiplying the deviation between the operation force signal and the target operation reaction force by a proportional gain to the adder 38 (proportional output). The multiplier 39 outputs a value obtained by multiplying the deviation between the operation force signal and the target operation reaction force by an integral gain to the integrator 40. The integrator 40 integrates the output of the multiplier 39 and outputs it to the adder 38 (integration output). The adder 38 outputs a feedback assist force that is the sum of the proportional output and the integral output to the adder 41.

  The FF controller 42 includes an FF compensation table block 43 and a multiplier 44. The FF compensation table block 43 outputs preset values corresponding to the stroke angle signal, the operation speed, and the operation acceleration to the multiplier 44. The multiplier 44 outputs a value obtained by multiplying the FF assist force by the FF gain, that is, a feed forward assist force to the adder 41.

  The adder 41 outputs the output sum (feedback assist force + feedforward assist force) of the FB control unit 36 and the FF control unit 42, that is, the target assist force, to the motor drive control block 45.

  A motor drive control block (corresponding to an assist force control unit) 45 drives the electric motor 15 based on the target assist force.

  The operating force determining means 46 (corresponding to the operating force presence / absence determining means together with the infrared sensor 49) determines whether or not the select lever 2 is being operated based on the detection signal from the infrared sensor 49, and the result is determined as the second input operating force. The result is output to the calculation unit 47.

The second input operation force calculation unit 47 (corresponding to the second input operation force calculation means) has an LPF 471 (corresponding to characteristic change detection means) that allows only the low frequency component of the output signal of the torque sensor 21 to pass inside. Normally, a signal corresponding to the change amount of the DC component of the torque sensor 21 is output to the third input operating force calculation unit 48.
When the second input operating force calculation unit 47 receives a signal indicating that the operation is being performed from the operating force determination unit 46, the second input operating force calculation unit 47 does not perform the output process of the torque sensor 21 that has newly passed the LPF 471, and before that, The calculated output value is held, and the held value is output to the third input operating force calculation unit 48.

  The third input operating force calculator 48 (corresponding to the third input operating force calculator) has an adder, and subtracts the torque value from the second input operating force calculator 47 from the torque value from the torque sensor 21. And output to the adder 35.

Next, the detent structure of the automatic transmission 19 will be described.
FIG. 4 is a perspective view showing a detent structure of the automatic transmission 19.
The control arm 20 is provided with a rotation shaft 26, and a detent plate 27 is supported on the rotation shaft 26. At the upper end of the detent plate 27, a valley portion 27b corresponding to five ranges (P, R, N, D, and L) is formed between the cam peaks 27a. Then, the detent pin 29 formed at the tip of the spring plate 28 is engaged with the valley portion 27b and the selected range position is maintained, thereby preventing an unintended range select due to vehicle vibration or the like. Yes.

  That is, the rotating shaft 26 is rotated by the operating force of the select lever 2, and the detent plate 27 is moved relative to the detent pin 29 in accordance with the rotation. At this time, the detent pin 29 gets over the cam crest 27 a and engages with the valley portion 27 b corresponding to the adjacent range, and the engaged state is held by the elastic force of the spring plate 28. This elastic force becomes a main load force when the select lever 2 is operated.

  Note that one end of the parking pole 30 is rotatably connected to the detent plate 27. When the select lever 2 is moved to the P range, the parking pole 30 prevents rotation of the parking gear 32 via the cam-like plate 31 and locks driving wheels (not shown). Thereby, when the vehicle is parked on the slope road in the P range, a vehicle load is applied so as to lock the driving wheel according to the slope, and acts as a force for biting the parking pole 30.

Next, the operation will be described.
[Select lever assist control processing]
FIG. 5 is a flowchart showing a flow of assist control processing of the select lever 2 executed by the control unit 22.

  In step S1, the operation force is read from the operation force signal of the torque sensor 21, and the process proceeds to step S2.

  In step S2, the stroke angle is read from the stroke angle signal of the potentiometer 25, and the process proceeds to step S3.

  In step S3, the operation direction of the select lever 2 is calculated from the stroke angle of the select lever 2 and the increase / decrease difference between the stroke angles read in the previous control cycle, and the process proceeds to step S4.

  In step S4, the operation speed of the select lever 2 is calculated from the stroke angle of the select lever 2 and the change rate of the stroke angle read in the previous control cycle, and the operation acceleration of the select lever 2 is calculated from the differential value of the operation speed. Then, the process proceeds to step S5.

  In step S5, an FF compensation table reading process is performed, and the process proceeds to step S6. The optimum FF compensation table is selected from a plurality of preset tables according to the stroke angle, the operation speed, and the operation acceleration.

  In step S6, target table reading processing is performed, and the process proceeds to step S7.

  In step S7, the FF assist force is set from the read FF compensation table, and the process proceeds to step S8.

  In step S8, the FB assist force is set from the read target table, and the process proceeds to step S9.

  In step S9, the target assist force is set from the sum of the set FF assist force and FB assist force, and the process proceeds to step S10.

  In step S10, the start / stop of the control is determined, the output duty ratio of the electric motor 15 is controlled so that the target assist force is obtained when the control is started, and when the control is stopped, the electric motor 15 is driven. This control is terminated without starting.

[Operation reaction force characteristics of automatic transmission]
FIG. 6 is a characteristic diagram showing an operation reaction force generated in the select lever 2 in the P → R range direction, more precisely, the select knob 4 held by the driver. This operation reaction force characteristic is an axis detected as an operation reaction force on the output shaft 12 of the assist actuator 9 when the driver operates the select lever 2 in the P → R range direction without driving the electric motor 15. The torque is converted as an operation reaction force Fm [N] generated in the select knob 4 and compared with the stroke angle acquired by the potentiometer 25.

  This operation reaction force is a combination of the load force generated by the detent of the automatic transmission 19 described above and the frictional force of the control cables 8 and 18 and the inertia of the electric motor 15. That is, in order to switch the range in the absence of the assist force by the electric motor 15, a manual operation force greater than the operation reaction force Fm is required.

  As shown in FIG. 6, the operation reaction force Fm generated when the select lever 2 is operated in the P → R range direction is initially opposite to the operation direction of the select lever 2 (D → N range) between the ranges. Direction), changes direction after the peak, occurs in the same direction as the operation direction (P → R range direction), and converges to zero near the range switching position (stop position). This characteristic is caused by the load force generated when the detent pin 29 gets over the cam crest 27 a of the detent plate 27. That is, until the detent pin 29 gets over the cam mountain 27a, a resistance force is generated by the urging force of the spring plate 28. After the detent pin 29 gets over the cam mountain 27a, the detent pin 29 moves to This is because a pulling force (inertial force) is generated by falling into the groove.

[Target operation reaction force characteristics]
FIG. 7 is a characteristic diagram showing the target operation reaction force of the select lever 2 in the P → R range direction. This target operation reaction force characteristic is obtained by setting in advance a target operation reaction force Ft [N] that provides a favorable operation characteristic with a sense of moderation for the driver according to the stroke angle of the select lever 2.

[FF control assist force map]
FIG. 8 is an assist force map in the P → R range direction in the FF control. In this assist force map, an operation force that is about ½ of the detent operation force in FIG. 6 is assisted by the FF control according to the stroke angle of the select lever 2.

  [FF control + FB control]

  In the first embodiment, the target assist force is a feedforward assist force Fff [N] that is set to be an operation force that is approximately ½ of the detent operation reaction force, and the actual operation force and the target operation reaction force Ft. By using two components with the feedback assist force FFb [N] set based on the deviation, in the assist control of the select lever with a steep and large torque deviation, both responsiveness and disturbance suppression can be achieved at a high level, Good operating characteristics can be realized.

[Temperature sensor temperature compensation]
In the first embodiment, a torque sensor 21 that detects torque based on the magnetostriction characteristics of the member is used. A characteristic of the torque sensor 21 is temperature drift. For this reason, the DC component of the output signal of the torque sensor 21 is extracted by a LPF (low-pass filter) as a temperature drift component, and the drift component is canceled by subtracting it from the sensor signal.
Since the temperature drift of the torque sensor 21 proceeds so as to be expressed by a thermal time constant, the change is small immediately after the cancellation process, and the change gradually increases as it is later. The normal operation of the select lever 2 does not cause a problem because the shift position is switched in a short time. That is, after the temperature drift is canceled, the operation starts and ends in a state with little change, so that the torque detection is accurately detected without being affected by the temperature drift.

  However, if the period during which the operating force is applied to the select lever 2 becomes long, that is, if the operation is performed very slowly by placing a hand, the temperature drift proceeds during that time. When the processing is performed, the output of the torque sensor is affected by the temperature drift, and the accuracy decreases. For this reason, the select lever 2 at the time of assist-controlled range switching is too heavy or too light, and sufficient operation feeling cannot be obtained.

  On the other hand, in the first embodiment, the operation force determination means 46, the second input operation force calculation unit 47, the third input operation force calculation unit 48, and the infrared sensor 49 are provided.

[Processing of input signal from torque sensor]
FIG. 9 is a flowchart showing a flow of processing of an input signal from the torque sensor 21 executed by the control unit 22.

  In step S <b> 11, the input operation force is detected by the torque sensor 21 as the first input operation force, and the stroke angle is detected by the select lever 2.

  In step S12, the infrared sensor 49 and the operation force determination unit 46 determine whether or not the operation force is applied.

  In step S13, if the operating force is applied, the process proceeds to step S14, and if the operating force is not applied, the process proceeds to step S15.

  In step S14, the second input operating force is held at the previous value without being newly calculated.

  In step S15, a second input operation force is newly calculated from the first input operation force.

  In step S16, a third input operating force is calculated from the first and second input operating forces.

  In step S17, a control command value to the assist actuator 9 is calculated from the third input operating force and the stroke angle (select lever operating position).

[Operation to maintain detection accuracy of torque sensor]
First, a decrease in detection accuracy when the second input operation force and the third input operation force are used and the process of step S14 is not performed will be described with reference to FIG.
When a temperature drift occurs with respect to the true operating force that is not affected by the temperature drift shown in FIG. 10, the value actually detected by the torque sensor 21 drifts to become the first input operating force in FIG. On the other hand, the second input operating force obtained by passing through the LPF 471 gradually changes as shown in FIG. 10 depending on the thermal time constant of the torque sensor 21, and the operation period of the select lever 2 is long. The influence will come out to the third input operation force via the second input operation force. If this change affects the assist control amount, the operation of the select lever 2 becomes heavy or light.

In the first embodiment, the infrared sensor 49 provided on the select knob 4 detects that the hand has been brought close to the operation, and the determination is made in the process in step S13, and the second input operation force is newly determined in the process in step S14. The previous value is not calculated.
Then, as shown in FIG. 11, the influence of the temperature drift is temporarily fixed to the second input operation force before coming out to the second input operation force, and the second input from the first input operation force. The third input operating force calculated by subtracting the operating force is a value that is not affected by temperature drift, and even when the operation is performed for a long period of time, the value of the torque sensor is high and the operation feeling is good. Select assist can be performed.

Next, the effect will be described.
In the automatic transmission select assist device of the present embodiment, the following effects can be obtained.

(1) The select lever 2 has a projection amount of about 150 mm less than the conventional select lever, and the select lever 2 and the control arm 20 are connected via control cables 8 and 18. The degree of freedom of the interior layout of the vehicle is greater than that of the product, and the select lever 2 can be set at an arbitrary position in the vehicle interior such as an instrument panel.
Further, since the select lever 2 and the control arm 20 are mechanically connected by the control cables 8 and 18, the driver can manually switch the range position even when the assist actuator 9 or the control unit 22 fails.

  In addition, an operating force determination unit 46 that determines that an operating force is applied to the select lever 2, an LPF 471 that detects a temperature drift amount of the torque sensor, and a temperature drift amount that is calculated by the LPF 471 with respect to the torque sensor 21. The second input operation force is calculated when the second input operation force is calculated and the operation force determination unit 46 determines that the operation force is applied. 47 and a third input operation force calculation unit 48 that calculates a third input operation force obtained by subtracting the second input operation force from the first input operation force, and the control unit 22 uses the third input operation force as the input operation force. Since force is used, it is possible to suppress a decrease in detection accuracy of the input operation force even when the operation force is applied.

  (2) Since the operation force determination unit 46 detects the proximity of the operator's hand to the select lever 2 with the infrared sensor 49, the operation of the operator can be detected reliably.

  FIG. 12 shows an example in which the operating force determination unit 46 determines that the operating force is applied when an assist command is issued from the control unit 22 to the assist actuator 9.

As shown in FIG. 12, a signal indicating that the infrared sensor 49 is not provided and output to the assist actuator 9 is input from the motor drive control unit 45 to the operation force determination unit 46 as compared with the first embodiment. The period during which the assist control is being performed is determined to be in operation.
Since other configurations and operations are the same as those of the first embodiment, the description thereof is omitted.

Next, the effect will be described.
The select assist device for an automatic transmission according to the second embodiment has the following effects in addition to the effect (1).
(3) Since the operation force determination unit 46 determines that the operation force is applied when an assist command is issued from the control unit 22 to the assist actuator 9, the cost is suppressed without providing a sensor. Even when the operating force is applied, it is possible to suppress a decrease in detection accuracy of the input operating force.

  FIG. 13 shows the first when the operating force is not applied from the temperature detecting means for detecting the temperature in the vicinity of the input operating force detecting means and the temperature detected by the temperature detecting means. The operating force is applied based on the difference between the zero level estimating means for estimating the input operating force and the estimated value of the first input operating force and the first input operating force when the operating force by the zero level estimating means is not applied. 3 is an example of a select assist device for an automatic transmission that determines whether or not a transmission is in progress.

That is, as shown in the block diagram of FIG. 13, a temperature sensor 53 (corresponding to a temperature detection means) is provided so as to detect the temperature of the torque sensor 21 or the temperature around the torque sensor 21.
Further, the control unit 22 includes a first input operation force estimation unit 50 (corresponding to zero level estimation means) that estimates a first input operation force when no operation is performed based on a temperature signal from the temperature sensor 53. An adder 51 is provided for determining the difference between the first input operation force when the operation is not performed and the first input operation force detected by the torque sensor 21, and it is determined from this difference whether the operation is in progress. An operating force determination unit 52 is provided.

The temperature of the torque sensor 21 or the surroundings of the torque sensor 21 is detected, and the first input operating force in a state where there is no operation, that is, the zero level is estimated, and the difference between the zero level and the actual first input operating force. Thus, while considering the temperature drift, the change in the third input operating force as shown in FIG. 10 does not occur, and the assist control can be performed with high accuracy.
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

Explain the effect.
The select assist device for an automatic transmission according to the third embodiment has the following effects in addition to the effect (1).
(4) The first input operation in which the operating force determination unit 52 estimates the first input operating force when no operating force is applied from the temperature sensor 53 that detects the temperature near the torque sensor 21 and the detected temperature. Since it is determined whether or not the operation force is applied based on the difference between the first input operation force of the force estimation unit 50 and the torque sensor 21, it can be determined whether or not the operation is applied with higher accuracy. The operating force can be detected with high accuracy.

  In the fourth embodiment, even if the second input operation force calculation means is determining that the operation force is applied to the select lever by the operation force presence / absence determination means, the determination period is the heat of the input operation force detection means. In this example, when the time constant or the zero point drift time constant becomes longer than a predetermined period, the second input operating force is stopped from being held at the value before the calculation.

That is, in the fourth embodiment, as shown in FIG. 14, the timer 54 is provided so that the second input operating force calculation unit 47 can detect the elapsed time.
Other configurations are the same as those of the second embodiment, and thus the description thereof is omitted.

In the example in which it is determined that the assist control shown in the second embodiment is being operated, and the second input operation force is held at the immediately preceding value, the second input operation force is held, thereby causing an influence as shown in FIG. The receiving state is excluded, and the third input operating force is kept highly accurate as shown in FIG. However, when the operation period is very long, the temperature drift becomes a large value (see FIG. 15).
Since the temperature drift of the torque sensor 21 is expressed by a thermal time constant, the temperature drift is searched when the time for the thermal time constant is exceeded.
For this reason, in the fourth embodiment, a timer 54 is provided in the control unit 22, and when the second input operation force is held by the operation force determination unit 46, the elapsed time is measured by the timer 54 and determined in advance from the characteristics of the torque sensor 21. If the elapsed time exceeds the thermal time constant, the holding of the second input operating force is stopped as shown in FIG. Then, since the second input operation force is newly calculated by the second input operation force calculator 47 using the LPF 471, the value takes into account the temperature drift as shown in FIG. 16, and the detection error is reduced.

Explain the effect.
The select assist device for an automatic transmission according to the fourth embodiment has the following effects in addition to the effects (1) and (3).
(4) Even if the second input operation force calculation unit 47 is determining that the operation force is applied to the select lever 2 by the operation force determination unit 46, the determination period is the thermal time constant of the torque sensor 21. Alternatively, when the zero point drift time constant becomes longer than a predetermined period, the second input operating force is stopped from being held at the value before the calculation. Detection error can be reduced.

(Other embodiments)
As mentioned above, although embodiment of this invention has been demonstrated based on Examples 1-4, the concrete structure of this invention is not limited to an Example, The range which does not deviate from the summary of invention. Design changes and the like are included in the present invention.
For example, in the first embodiment, the torque sensor 21 is used as the input operation force detection means for detecting the input operation force of the select lever 2. However, the input operation is performed based on the supply current value to the electric motor 15, the rotation speed of the electric motor 15, and the like. It is good also as a structure which estimates force.
In the first embodiment, the configuration in which the select lever 2 and the control arm 20 of the automatic transmission 19 are connected by the control cables 8 and 18 is shown. However, the operation force transmitting means for transmitting the operation force of the select lever 2 to the control arm 20 is arbitrary. It is good also as a structure using a rod or linkage.
The shape and size of the select lever 2 are arbitrary, and may be a switch shape that can be operated with a fingertip. In addition, the target operation reaction force characteristic is also changed to a characteristic that provides good operation characteristics according to the shape of the select lever 2.

The distribution ratio between the FF assist force Fff and the FB assist force Ffb with respect to the target assist force can be freely set according to the target operation characteristics.
In the first embodiment, the infrared sensor 49 is used as the operation force presence / absence determination unit. However, a touch sensor that detects pressure (load) transmitted from the hand to the select knob may be used.
In the fourth embodiment, the thermal time constant of the torque sensor is used as the predetermined period for stopping the holding of the second input operating force. However, the zero point drift time constant is used as a circuit system for handling the torque sensor signal including the torque sensor. May be used.
Further, this zero point drift time constant may have another definition.

1 is a side view illustrating a configuration of an automatic transmission according to a first embodiment. It is a principal part perspective view which shows the detailed structure of an assist actuator. It is a control block diagram of a control unit. It is a perspective view which shows the structure of the detent of an automatic transmission. It is a flowchart which shows the flow of the assist control process of the select lever performed with a control unit. It is a characteristic view which shows the operation reaction force which generate | occur | produces in a select lever in the P → R range direction. It is a characteristic view which shows the target operation reaction force of the select lever in the P → R range direction. It is a FF assist force map in the P → R range direction. It is a flowchart which shows the flow of a process of the torque value and stroke angle value which are performed with a control unit. In Example 1, it is explanatory drawing which shows the relationship of the 1st input operation force, the 2nd input operation force, and the 3rd input operation force when not performing the process of step S14. It is explanatory drawing which shows the relationship between the 1st input operation force in Example 1, the 2nd input operation force, and the 3rd input operation force. FIG. 6 is a control block diagram of a control unit according to a second embodiment. FIG. 10 is a control block diagram of a control unit according to a third embodiment. FIG. 10 is a control block diagram of a control unit according to a fourth embodiment. In Example 4, it is explanatory drawing which shows the relationship between the 1st input operation force, the 2nd input operation force, and the 3rd input operation force when not hold | maintaining holding | maintenance of 2nd input operation force. It is explanatory drawing which shows the relationship between the 1st input operation force in Example 4, the 2nd input operation force, and the 3rd input operation force.

Explanation of symbols

1 select mechanism 2 select lever 3 center cluster 4 select knob 5 fulcrum shaft 7 select lever joint 8 control cable 9 assist actuator 10 input lever 11 input lever joint 12 output shaft 13 output lever 14 worm gear 15 electric motor 16 motor output shaft 17 output Lever joint 18 Control cable 19 Automatic transmission 20 Control arm 21 Torque sensor 22 Control unit 23 Wire harness 24 Contact 25 Potentiometer 26 Rotating shaft 27 Detent plate 27a Cam mountain 27b Valley 28 Spring plate 29 Detent pin 30 Parking pole 31 Cam shape Plate 32 Parking gear 33 Direction discrimination block 34 Target table block 35 Adder 36 FB Control Unit 37 Multiplier 38 Adder 39 Multiplier 40 Integrator 41 Adder 42 FF Control Unit 43 FF Compensation Table Block 44 Multiplier 45 Motor Drive Control Block 46 Operating Force Determination Unit 47 Second Input Operating Force Calculation Unit 48 Third Input operation force calculation unit 49 Infrared sensor 50 First input operation force estimation unit 51 Adder 52 Operation force determination unit 53 Temperature sensor

Claims (5)

Input operation force detecting means for detecting, as a first input operation force, an input operation force to a select lever connected to a range position switching device of an automatic transmission;
An operation position detecting means for detecting an operation position of the select lever;
An assist actuator that outputs an assist force to assist the operating force of the driver to the select lever;
An assist force control means for outputting a control command for changing the assist force to the assist actuator based on the detected input operation force and the operation position;
A selection assist device for an automatic transmission having
Operating force presence / absence determining means for determining that an operating force is applied to the select lever;
A characteristic change detecting means for detecting a characteristic change amount of the input operation force detecting means;
When a second input operating force that is a characteristic change detected by the characteristic change detecting unit is calculated with respect to the first input operating force, and it is determined that the operating force is applied by the operating force presence / absence determining unit Second input operation force calculating means for holding the second input operation force at a value before calculation;
Third input operation force calculating means for calculating a third input operation force obtained by subtracting the second input operation force from the first input operation force;
With
A selection assist device for an automatic transmission, wherein the assist control means uses a third input operation force as an input operation force. In the automatic transmission select assist device according to claim 1,
The operating force presence / absence determining means is
A selection assist device for an automatic transmission, wherein the proximity of an operator's hand to the select lever is detected by a sensor. In the automatic transmission select assist device according to claim 1,
The operating force presence / absence determining means is
When an assist command is issued from the assist control means to the assist actuator, it is determined that an operating force is applied.
A select assist device for an automatic transmission. In the automatic transmission select assist device according to claim 1,
The operating force presence / absence determining means is
Temperature detecting means for detecting a temperature in the vicinity of the input operating force detecting means;
Zero level estimating means for estimating a first input operating force when no operating force is applied from the temperature detected by the temperature detecting means;
With
It is characterized in that it is determined whether or not the operating force is applied based on the difference between the estimated value of the first input operating force and the first input operating force when the operating force by the zero level estimating means is not applied. Select assist device for automatic transmission. In the automatic transmission select assist device according to claim 1,
The second input operating force calculation means is
Even if it is determined that the operation force is applied to the select lever by the operation force presence / absence determination means, the determination period is determined in advance from the thermal time constant or zero point drift time constant of the input operation force detection means. When it becomes larger than the predetermined period, the second input operation force is stopped from being held at the value before the calculation.
A select assist device for an automatic transmission.

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