DOOR OPENING AND CLOSING ASSISTING APPARATUS

A door opening and closing assisting apparatus that assists an opening and closing operation of a door on a vehicle is provided. The door opening and closing assisting apparatus includes: an information obtainer that obtains information on an opening and closing acceleration of the door; a door actuator that performs driving for assisting the opening and closing operation of the door; a target assisting power computer that computes a target assisting power for assisting the opening and closing operation of the door; and a controller that performs driving control for the door actuator based on the target assisting power. The controller starts the driving control for the door actuator at a timing at which the information obtainer obtains the opening and closing acceleration of the door.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of foreign priority to Japanese Patent Application No. 2022-037199, filed on Mar. 10, 2022, which is incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a door opening and closing assisting apparatus that assists in opening and closing of a door on a vehicle.

BACKGROUND

There is conventionally known a door opening and closing assisting apparatus that assists in opening and closing of a door by applying an assisting power to a door opening and closing operation power exerted by an operator of a vehicle (see JP2007-238014A). The door opening and closing assisting apparatus according to JP2007-238014A includes a torque sensor that detects a door opening and closing operation power exerted to a door knob on a vehicle, a velocity sensor that detects the velocity of opening and closing of the door, a motor that assists the door opening and closing operation power, and a controller that controls the motor using an assisting power instruction value computed from the door opening and closing operation power and the opening and closing velocity. The controller computes the assisting power instruction value based on the mass of the door, a viscous friction coefficient determined by the relation between a viscous friction force acting on the door and a moving velocity, and a virtual mass and a virtual viscosity friction coefficient for attaining ideal operability.

The door opening and closing assisting apparatus according to JP2007-238014A computes the assisting power instruction value based on the opening and closing operation power and opening and closing velocity of the door and controls the motor based on the assisting power instruction value obtained as a result of the computation. Thus, the control logic is established with a small number of parameters, and therefore, setting, development, and the like can be done readily with a clear configuration.

Meanwhile, in order for a door opening and closing assisting apparatus like the one disclosed in JP2007-238014A to be used widely, not only favorable operability for opening and closing the door, but also simplicity of the configuration of the apparatus is demanded.

In this regard, the door opening and closing assisting apparatus according to JP2007-238014A has room for improvement in terms of achieving favorable operability for opening and closing a door with a simple apparatus configuration.

The present invention has been made to solve the above problem and has an object to provide a door opening and closing assisting apparatus capable of achieving favorable operability for door opening and closing with a simple apparatus configuration.

SUMMARY

To achieve the above object, one aspect of the present invention is mainly characterized as a door opening and closing assisting apparatus that assists an opening and closing operation of a door on a vehicle, the door opening and closing assisting apparatus including: an information obtainer that obtains information on an opening and closing acceleration of the door; a door actuator that performs driving for assisting the opening and closing operation of the door; a target assisting power computer that computes a target assisting power for assisting the opening and closing operation of the door; and a controller that performs driving control for the door actuator based on the target assisting power, in which the controller starts the driving control for the door actuator at a timing at which the information obtainer obtains the opening and closing acceleration of the door.

DETAILED DESCRIPTION

Referring to the drawings as needed, the following provides a detailed description of a door opening and closing assisting apparatus according to an embodiment of the present invention.

Note that throughout the drawings to be referred to below, members having the same function are denoted by the same reference sign. Also, the size and shape of a member may be schematically shown and may be modified or exaggerated for explanatory convenience.

When a description is given using directions, the directions are based on the front and rear, left and right, and up and down as seen from a driver sitting in the driver's seat (the front right seat) unless otherwise noted. In other words, a “front-back direction” corresponds to a “vehicle length direction,” a “left and right direction” corresponds to a “vehicle width direction,” and an “up-down direction” corresponds to a “vehicle height direction.”

In the description of a vehicle11equipped with a door opening and closing assisting apparatus10according to the embodiment of the present invention, a plurality of members forming the vehicle body of the vehicle11are formed using a metal material such as a steel plate, unless otherwise noted.

[Configuration of Door Opening and Closing Assisting Apparatus10]

First, the configuration of the vehicle11equipped with the door opening and closing assisting apparatus10according to the embodiment of the present invention is described with reference toFIGS.1A and1Bas needed.

FIG.1Ais a perspective view of an outer appearance of the vehicle11equipped with the door opening and closing assisting apparatus10according to the embodiment of the present invention.FIG.1Bis a perspective view showing how the door opening and closing assisting apparatus10is attached to a door13.FIG.2is a functional block configuration diagram of the door opening and closing assisting apparatus10. InFIG.3A, (a) is a diagram conceptually showing, in contradistinction, the relation between a standard assisting power Psd and a target assisting power Ptg in a door opening operation with the door opening and closing velocity being changed, and (b) is a diagram conceptually showing, in contradistinction, the relation between the standard assisting power Psd and the target assisting power Ptg in a door closing operation with the door opening and closing velocity being changed.FIG.3Bis a diagram conceptually showing, in contradistinction, the relation of the target assisting power Ptg to an opening and closing velocity Vdr of a door14for each of variously changed attitudes of the vehicle11in an opening operation of the door14.FIG.3Cis a diagram conceptually showing, in contradistinction, the relation of the target assisting power Ptg to the opening and closing velocity Vdr of the door14for each of variously changed attitudes of the vehicle11in a closing operation of the door14.FIG.3Dis a diagram conceptually showing suitable increase or decrease corrections made on the standard assisting power Psd for various attitudes of a vehicle11in each of door opening and closing operations of the door14.

As shown inFIG.1A, the vehicle11equipped with the door opening and closing assisting apparatus10according to the embodiment of the present invention includes, on its sides, left and right front seat doors13, left and right rear seat doors15, and left and right side sills17. Note that the front seat doors13and the rear seat doors15are collectively called “doors14” in the following description unless a distinction therebetween is necessary.

As shown inFIG.1B, the front seat doors13(the doors14) are each swingably attached to a vehicle body20via a pair of hinge mechanisms13A and13B arranged in the vehicle height direction, so that the front seat door13is freely openable and closable. The doors14are each provided with a door actuator19of the door opening and closing assisting apparatus10, the door actuator19performing driving for assisting an opening and closing operation of the door14.

As shown inFIG.1B, the door actuator19is configured including a spindle screw21having a screw groove axially formed in its outer circumference and a door motor25having a spindle nut (not shown) having a screw groove formed in its inner circumference to threadably engage with the screw groove on the spindle screw21, the spindle nut being connected to a rotor (not shown) via a speed reduction mechanism (not shown).

One end of the spindle screw21is pivotally supported via a joint mechanism23provided on the vehicle body20. The other end of the spindle screw21is provided with the door motor25. The door motor25is fixedly provided on the inner side of the front seat door13(the door14).

In the door opening and closing assisting apparatus10according to the embodiment of the present invention, when an operator performs an operation for opening and closing the door14, the door actuator19starts driving, triggered by the opening or closing movement of the door14caused by the opening or closing operation.

For instance, in a case where an operator performs an operation for opening the door14, the door14undergoes opening movement caused by the opening operation.

In response to the opening movement of the door14, the rotor of the door motor25provided at the free end of the spindle screw21is mechanically driven and rotated. When no electric power is being fed to the door motor25, the door motor25serves to hinder the opening movement of the door14as a power generation device. In this state, the operator experiences a resistance against the opening or closing operation of the door14and is therefore unable to have favorable operability for opening or closing the door14.

Thus, when the door14is opened, a door ECU28provided at the front seat door13(the door14) determines whether a condition to start driving of the door actuator19(to be detailed later) is satisfied. Driving of the door actuator19is started if it is determined that the condition to start driving of the door actuator19is satisfied.

Once driving of the door actuator19is started, the door motor25is supplied with electric power so that the opening movement of the door14may be performed. Assisting power enabled by this power supply is added to the operation power of the operator. This reduces resistance that the operator feels when performing an operation for opening and closing the door14, providing them with favorable operability for opening and closing the door14.

When the condition to start driving of the door actuator19is satisfied, the door opening and closing assisting apparatus10according to the embodiment of the present invention calculates, based on the opening and closing velocity Vdr of the door14, the standard assisting power Psd which is assisting power required to maintain the opening and closing velocity Vdr, and corrects the calculated standard assisting power Psd in order to improve the operability for opening or closing the door14and to have favorable operability comparable to that in a case where the vehicle11has a horizontal attitude.

More specifically, when the attitude of the vehicle11(including tilts in the front-back direction and the left-right direction) is horizontal, the door opening and closing assisting apparatus10makes the correction by decreasing the calculated standard assisting power Psd based on a predetermined rule and sets the standard assisting power Psd thus corrected by being decreased as a target assisting power Ptg.

Meanwhile, when the attitude of the vehicle11is not horizontal, the door opening and closing assisting apparatus10makes the correction by increasing or decreasing the calculated standard assisting power Psd according to the attitude of the vehicle and the openness degree Odr of the door14so as to be able to attain favorable operability comparable to that in a case where the vehicle11has a horizontal attitude, and sets the standard assisting power Psd thus corrected by being increased or decreased as the target assisting power Ptg.

Favorable operability for opening and closing the door14can thereby be achieved with a simple apparatus configuration. Details of this will be described sequentially.

To implement the functions described above, the door opening and closing assisting apparatus10according to the embodiment of the present invention is configured including, as shown inFIG.2, functional units belonging to each of an input system27, an information processing system (door ECU)28, and an output system29.

The functional units belonging to the input system27are configured including a Hall sensor31and an acceleration sensor32.

The Hall sensor31outputs detection signals including chronological information on the rotation position and rotation velocity of the rotor of the door motor25belonging to the door actuator19.

Output signals from the Hall sensor31are sequentially sent to an information obtainer33belonging to the door ECU28. The Hall sensor31corresponds to the “openness degree sensor” of the present invention.

The acceleration sensor32outputs a detection signal indicative of a roll angle, a detection signal indicative of a pitch angle, and a detection signal indicating of a yaw angle. When the front-back direction, the left-right direction (the vehicle width direction), and the up-down direction (the vehicle height direction) of the horizontal and stationary vehicle11are an x-axis direction, a y-axis direction, and a z-axis direction, respectively, the roll angle is a rotation angle about the x-axis as a rotary axis, the pitch angle is a rotation angle about the y-axis as a rotary axis, and the yaw angle is a rotational angle about the z-axis as a rotary axis.

As shown inFIG.1B, the acceleration sensor32is mounted on a board (not shown) of the door ECU28.

The output signals (a roll angle, a pitch angle, and a yaw angle) from the acceleration sensor32are sequentially sent to the information obtainer33belonging to the door ECU28.

Functional units belonging to the information processing system (door ECU)28are configured including the information obtainer33, a determiner35, a target assisting power computer37, and a controller39.

The information obtainer33converts the output signals sent from the Hall sensor31into chronological information on the opening and closing velocity Vdr and the openness degree Odr of the door14.

The information obtainer33also converts the output signals (a roll angle, a pitch angle, and a yaw angle) sent from the acceleration sensor32into chronological information on a front-back tilt angle Afb and a left-right tilt angle Alr.

The information obtainer33further converts each of the output signals (a roll angle, a pitch angle, and a yaw angle) sent from the acceleration sensor32into chronological information on an opening and closing acceleration αdr_y and a vehicle height acceleration αdr_z of the door14.

The information obtainer33thereby obtains the chronological information on the opening and closing velocity Vdr and the openness degree Odr of the door14based on the output signals sent from the Hall sensor31as well as the chronological information on the front-back tilt angle Afb and the left-right tilt angle Alr and the chronological information on the opening and closing acceleration αdr_y and the vehicle height acceleration αdr_z of the door14based on the output signals from the acceleration sensor32.

Note that as the openness degree Odr of the door14, the current position of the door14in a relative coordinate system can be expressed by, for example, setting a definition range by allocating a numeric value “0” to a fully closed (closed) state and a numeric value “100” to a fully opened state (a state where the door is opened to the utmost limit) and assigning appropriate numeric values 1 to 99 to the current open/close positions.

As the front-back tilt angle Afb, the attitude (tilt angle) of the vehicle11in the front-back direction in a relative coordinate system can be expressed by, for example, assigning a numeric value “0” to the horizontal state, a positive numeric value to a frontward tilting state, and a negative numeric value to a rearward tilting state.

Similarly, as the left-right tilt angle Alr, the attitude (tilt angle) of the vehicle11in the left-right direction in a relative coordinate system can be expressed by, for example, assigning a numeric value “0” to the horizontal state, a positive numeric value to a leftward tilting state, and a negative numeric value to a rightward tilting state.

The opening and closing acceleration αdr_y of the door14is an acceleration acting in the left-right direction (the vehicle width direction: the y-axis direction) of the door14.

Also, the vehicle height acceleration αdr_z of the door14is an acceleration acting in the up-down direction (the vehicle height direction: the z-axis direction) of the door14.

The chronological information obtained by the information obtainer33, namely the chronological information on the opening and closing velocity Vdr and the openness degree Odr of the door14, the chronological information on the front-back tilt angle Afb and the left-right tilt angle Alr, and the chronological information on the opening and closing acceleration αdr_y and the vehicle height acceleration αdr_z of the door14, are sent to the determiner35.

The determiner35not only determines the direction of the opening and closing operation of the door14, but also determines whether the opening and closing acceleration αdr_y of the door14is above a predetermined opening and closing acceleration threshold αdr_yth, whether the vehicle height acceleration αdr_z of the door14is below a predetermined vehicle height acceleration threshold αdr_zth, and whether the opening and closing velocity Vdr of the door14is below a predetermined velocity threshold Vdrth.

Of the items determined by the determiner35, “whether the vehicle height acceleration αdr_z of the door14is below the predetermined vehicle height acceleration threshold αdr_zth” may be omitted.

The direction of the opening and closing operation of the door14may be obtained based on whether the sign of the difference between the openness degrees Odr that are a certain temporal interval apart from each other in the chronological information on the openness degree Odr of the door14is positive or negative.

The determination result on the direction of the opening and closing operation of the door14obtained by the determiner35is sent to the target assisting power computer37.

Also, the acceleration-related determination results obtained by the determiner35, namely whether the opening and closing acceleration αdr_y of the door14is above the predetermined opening and closing acceleration threshold αdr_yth and whether the vehicle height acceleration αdr_z of the door14is below the predetermined vehicle height acceleration threshold αdr_zth, are sent to the controller39.

If the opening and closing acceleration αdr_y of the door14is not above the predetermined opening and closing acceleration threshold αdr_yth or the vehicle height acceleration αdr_z of the door14is equal to or above the predetermined vehicle height acceleration threshold αdr_zth, it is highly probable that the values of the opening and closing acceleration αdr_y of the door14and the vehicle height acceleration αdr_z of the door14are a result of error detection. If driving of the door actuator19is started in such a case, the operator may experience a strange feeling as if the door14is moving against their will.

Thus, in the door opening and closing assisting apparatus10according to the embodiment of the present invention, driving of the door actuator19is started only when acceleration requirements are satisfied, the acceleration requirements being the opening and closing acceleration αdr_y of the door14being above the predetermined opening and closing acceleration threshold αdr_yth and the vehicle height acceleration αdr_z of the door14being below the predetermined vehicle height acceleration threshold αdr_zth.

A situation where the operator may experience a strange feeling as if the door14is moving against their will is thereby avoided.

Thus, values set as the predetermined opening and closing acceleration threshold αdr_yth and the predetermined vehicle height acceleration threshold αdr_zth may be any appropriate values (except for zero) indicating that the values of the opening and closing acceleration αdr_y of the door14and the vehicle height acceleration αdr_z of the door14are not a result of error detection.

In addition, the determination result obtained by the determiner35regarding whether the opening and closing velocity Vdr of the door14is below the predetermined velocity threshold Vdrth is sent to the controller39.

If, during the driving of the door actuator19, assisting power from the door actuator19continues to be applied until the opening and closing velocity Vdr of the door14becomes zero, the operator may experience a strange feeling as if the door14is coasting against their will.

Thus, in the door opening and closing assisting apparatus10according to the embodiment of the present invention, driving control of the door actuator19is stopped at a timing at which the opening and closing operation of the door14is expected to end soon, such as when the opening and closing velocity Vdr of the door14falls below the predetermined velocity threshold Vdrth.

A situation where the operator may experience a strange feeling as if the door14is coasting against their will is thereby avoided.

Thus, as the predetermined velocity threshold Vdrth, for example, a value of the opening and closing velocity Vdr of the door14(except for zero) indicating that the opening and closing movement of the door14is expected to end soon may be appropriately set.

The determiner35also determines whether the front-back tilt angle Afb of the vehicle11is above a predetermined front-back tilt angle threshold Afbth and whether the left-right tilt angle Alr of the vehicle11is above a predetermined left-right tilt angle threshold Alrth.

The determination results obtained by the determiner35on whether the front-back tilt angle Afb of the vehicle11is above the predetermined front-back tilt angle threshold Afbth and whether the left-right tilt angle Alr of the vehicle11is above the predetermined left-right tilt angle threshold Alrth are sent to the target assisting power computer37.

Note that the determiner35may be configured to determine that the opening and closing velocity Vdr of the door14is below the predetermined velocity threshold Vdrth when the opening and closing velocity Vdr of the door14stays below the predetermined velocity threshold Vdrth for a predetermine period of time.

This configuration is expected to offer an effect of avoiding a situation where driving control of the door actuator19is erroneously stopped precociously by mistiming the end of the opening or closing movement of the door14.

The target assisting power computer37computes the target assisting power Ptg for assisting an opening or closing operation of the door14.

To be more specific, the target assisting power computer37is configured including a standard assisting power calculator41that calculates the standard assisting power Psd based on the opening and closing velocity Vdr of the door14obtained by the information obtainer33, the standard assisting power Psd being assisting power required to maintain the opening and closing velocity Vdr; and a corrector43that corrects the standard assisting power Psd calculated by the standard assisting power calculator41in order to improve the operability for opening and closing the door14and to attain favorable operability comparable to that in a case where the vehicle11has a horizontal attitude even if the vehicle11does not have a horizontal attitude.

The standard assisting power calculator41of the target assisting power computer37calculates the standard assisting power Psd based on the opening and closing velocity Vdr of the door14obtained by the information obtainer33, the standard assisting power Psd being assisting power required to maintain the opening and closing velocity Vdr.

The corrector43of the target assisting power computer37performs correction processing on the standard assisting power Psd calculated by the standard assisting power calculator41, the correction processing being different depending on whether the vehicle11has a horizontal attitude or does not have a horizontal attitude (the vehicle11is tilted in the front-back and/or left-right direction).

Specifically, when the attitude of the vehicle11(including tilts in the front-back and left-right directions) is horizontal, the corrector43of the target assisting power computer37makes the correction by decreasing the standard assisting power Psd calculated by the standard assisting power calculator41based on a predetermined rule and sets the standard assisting power Psd thus corrected by being decreased as a target assisting power Ptg.

In this way, in a case of performing driving control of the door actuator19when the vehicle11has a horizontal attitude, the standard assisting power Psd thus corrected by being decreased is set as the target assisting power Ptg. Thus, compared to a case where the target assisting power Ptg is a standard assisting power Psd without the decrease correction, assisting power is applied so that the door14moves to follow the opening and closing operation performed by the operator with a delay.

As a result, the operator's power of opening and closing the door14can be assisted properly, not too much or too little, and thus, the operability for opening and closing the door14can be improved.

Meanwhile, when the vehicle11does not have a horizontal attitude (when the vehicle11is tilting in the front-back or left-right direction), the corrector43of the target assisting power computer37makes the correction by increasing or decreasing the standard assisting power Psd calculated by the standard assisting power calculator41based on the attitude of the vehicle11and the openness degree Odr of the door14(details will be described later) so as to offer favorable operability comparable to that in a case where the vehicle11has a horizontal attitude, and sets the standard assisting power Psd thus corrected by being increased or decreased as the target assisting power Ptg.

In this case, in a case of performing driving control of the door actuator19when the vehicle11does not have a horizontal attitude, the standard assisting power Psd calculated by the standard assisting power calculator41is corrected by being increased or decreased based on the attitude of the vehicle11and the openness degree Odr of the door14, and the standard assisting power Psd thus corrected by being increased or decreased is set as the target assisting power Ptg. Thus, even if the magnitude of gravity acting on the door14changes depending on the attitude of the vehicle11and the openness degree Odr of the door14, assisting power applied can be of a magnitude that eliminates the affect by this change, compared to a case where the target assisting power Ptg is not a standard assisting power Psd corrected by being increased or decreased based on the attitude of the vehicle11and the openness degree Odr of the door14.

As a result, the operator's operation power for opening and closing the door14can be properly assisted not too much or not too little, and thus, the operability for opening and closing the door14can be improved.

The target assisting power Ptg which is the computation result obtained by the target assisting power computer37is sent to the controller39.

Here, the correction by decreasing the standard assisting power Psd based on the predetermined rule is, for example, a concept including both of a mode of obtaining the target assisting power Ptg which is decreased by multiplication of the standard assisting power Psd by a predetermined decrease rate (e.g., approximately 3% to 20%) and a mode of obtaining the target assisting power Ptg which is decreased by subtraction of a predetermined value (e.g., a value corresponding to approximately 3% to 20%) from the standard assisting power Psd.

Note that there are no particular limitations for the standard assisting power Psd and the target assisting power Ptg, but for example, they can be obtained using a mode involving an output duty ratio [%].

Also, as shown in, for example, (a) and (b) ofFIG.3Ain contradistinction, the corrector43belonging to the target assisting power computer37makes a correction so that the amount of the decrease correction may be smaller for a closing operation of the door14than for an opening operation of the door14.

Thus, a situation where the door14hits the next vehicle in the opening operation of the door14is less likely to occur, and an experience of speedy closing of the door14can be offered in the closing operation of the door14.

The corrector43belonging to the target assisting power computer37further makes a correction by increasing or decreasing the standard assisting power Psd based on the information on the attitude of the vehicle11including front-back and left-right tilts.

To be more specific, as shown inFIGS.3B and3D, in a case where a force that hinders the open state of the door14is exerted in the opening operation of the door14due to a change in the attitude of the vehicle11(the door positioned upward at 17 degrees; the front side rising at 17 degrees), a correction is made so that the target assisting power Ptg may be larger than in a case where the vehicle11has a horizontal attitude. This correction is made by increasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

Note that “the door positioned upward at 17 degrees” means that the target is a door located at an upper side when the vehicle11is on a slope tilting in the vehicle width direction (at a tilt angle of 17°).

Meanwhile, “the front side rising at 17 degrees” means that the target is a door on the vehicle11being on a slope tilting in the vehicle length direction (at a tilt angle of 17°) in such a manner that the front of the vehicle11is directed upward.

By contrast, in a case where a force that promotes the open state of the door14is exerted in the opening operation of the door14due to a change in the attitude of the vehicle11(the door positioned downward at 17 degrees; the front side sinking at 17 degrees), a correction is made so that the target assisting power Ptg may be smaller than in a case where the vehicle11has a horizontal attitude. This correction is made by decreasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

Note that “the door positioned downward at 17 degrees” means that the target is a door located at a lower side when the vehicle11is on a slope tilting in the vehicle width direction (at a tilt angle of 17°).

Meanwhile, “the front side sinking at 17 degrees” means that the target is a door on the vehicle11being on a slope tilting in the vehicle length direction (at a tilt angle of 17°) in such a manner that the front of the vehicle11is directed downward.

Also, as shown inFIGS.3C and3D, in a case where a force that hinders the closed state of the door14is exerted in the closing operation of the door14due to a change in the attitude of the vehicle11(the door positioned downward at 17 degrees; the front side sinking at 17 degrees), a correction is made so that the target assisting power Ptg may be larger than in a case where the vehicle11has a horizontal attitude. This correction is made by increasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

By contrast, in a case where a force that promotes the closed state of the door14is exerted in the closing operation of the door14due to a change in the attitude of the vehicle11(the door positioned upward at 17 degrees; the front side rising at 17 degrees), a correction is made so that the target assisting power Ptg may be smaller than in a case where the vehicle11has a horizontal attitude. This correction is made by decreasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

Note that the correction for making the target assisting power Ptg larger or smaller due to a change in the attitude of the vehicle11may be made using a combined correction amount obtained by adding and combining a correction amount for the front-back tilt angle Afb and a correction amount for the left-right tilt angle Alr that have been independently obtained.

For the correction made by increasing or decreasing the standard assisting power Psd, in actuality, characteristics tables (or conversion formulae) for the target assisting power Ptg that changes according to a change in the opening and closing velocity Vdr of the door14are prepared in advance according to operation modes (opening and closing) of the door14and according to changes in the attitude of the vehicle11. The characteristics tables (conversion formulae) to be referred to are switched and used for each individual case (such as, for example, the door14is being operated to be open, the door14is positioned upward, and the vehicle11has a front rising attitude).

Favorable operability for opening and closing the door14is thus achieved with a simple apparatus configuration.

Because the corrector43belonging to the target assisting power computer37thus makes a correction by increasing or decreasing the standard assisting power Psd based on information on the attitude of the vehicle11including front-back and left-right tilts, driving control of the door actuator19is performed using the target assisting power Ptg of a magnitude suited to the change in the attitude of the vehicle11. As a result, even if the attitude of the vehicle11changes, favorable operability for opening and closing the door14can be achieved with a simple apparatus configuration.

When there is a change in the attitude of the vehicle11including front-back and left-right tilts, the magnitude of gravity acting on the door14changes depending on whether the openness degree Odr of the door14is large or small. In other words, there is a close relation between the openness degree Odr of the door14and the operability for opening and closing the door14.

Thus, the corrector43belonging to the target assisting power computer37makes a correction by increasing or decreasing the standard assisting power Psd based on information on the attitude of the vehicle11including front-back and left-right tilts and on the openness degree Odr of the door14.

To be more specific, as shown inFIGS.3B and3D, in a case where a force that hinders the open state of the door14is exerted in the opening operation of the door14due to a change in the attitude of the vehicle11(the door positioned upward at 17 degrees; the front side rising at 17 degrees), a correction is made so that the target assisting power Ptg may be larger than in a case where the vehicle11has a horizontal attitude. This correction is made by increasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

Specifically, the amount of correction made here on the standard assisting power Psd can be expressed as follows: [(the front-back tilt angle Afb*a tilt coefficient β)*the door openness degree Odr]. The larger the front-back tilt angle Afb and the larger the door openness degree Odr, the larger the above correction amount. Here, (the front-back tilt angle Afb*the tilt coefficient β) means an output (a duty ratio) necessary at the time of starting actuation of the door14(this is true hereinbelow as well).

By contrast, in a case where a force that promotes the open state of the door14is exerted in the opening operation of the door14due to a change in the attitude of the vehicle11(the door positioned downward at 17 degrees; the front side sinking at 17 degrees), a correction is made so that the target assisting power Ptg may be smaller than in a case where the vehicle11has a horizontal attitude. This correction is made by decreasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

Specifically, the amount of correction made here on the standard assisting power Psd can be expressed as follows: [(the front-back tilt angle Afb*the tilt coefficient β)*(the door openness degree Odr of the door fully opened−the door openness degree Odr)]. The larger the front-back tilt angle Afb, the larger the above correction amount, whereas the larger the door openness degree Odr, the smaller the above correction amount.

Also, as shown inFIGS.3C and3D, in a case where a force that hinders the closed state of the door14is exerted in the closing operation of the door14due to a change in the attitude of the vehicle11(the door positioned downward at 17 degrees; the front side sinking at 17 degrees), a correction is made so that the target assisting power Ptg may be larger than in a case where the vehicle11has a horizontal attitude. This correction is made by increasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

Specifically, the amount of correction made here on the standard assisting power Psd can be expressed as follows: [(the front-back tilt angle Afb*the tilt coefficient β)*the door openness degree Odr]. The larger the front-back tilt angle Afb and the larger the door openness degree Odr, the larger the above correction amount.

By contrast, in a case where a force that promotes the closed state of the door14is exerted in the closing operation of the door14due to a change in the attitude of the vehicle11(the door positioned upward at 17 degrees; the front side rising at 17 degrees), a correction is made so that the target assisting power Ptg may be smaller than in a case where the vehicle11has a horizontal attitude. This correction is made by decreasing the amount of correction on the standard assisting power Psd compared to that in a case where the vehicle11has a horizontal attitude.

Specifically, the amount of correction made here on the standard assisting power Psd can be expressed as follows: [(the front-back tilt angle Afb*the tilt coefficient β)*(the door openness degree Odr of the door fully opened−the door openness degree Odr)]. The larger the front-back tilt angle Afb, the larger the above correction amount, whereas the larger the door openness degree Odr, the smaller the above correction amount.

Such a configuration helps prevent a change in the attitude of the vehicle11, if any, from affecting the operability for opening and closing the door14and also helps prevent the openness degree Odr of the door14at that time from affecting the operability for opening and closing the door14. As a result, the operability for opening and closing the door14can be made to be favorable furthermore.

The controller39performs driving control for the door actuator19based on the target assisting power Ptg, which is the computation result obtained by the target assisting power computer37. Favorable operability for opening and closing the door14is thus achieved with a simple apparatus configuration.

Also, the controller39performs driving control for the door actuator19is started only when the acceleration requirements are satisfied, the acceleration requirements being the opening and closing acceleration αdr_y of the door14being above the predetermined opening and closing acceleration threshold αdr_yth and the vehicle height acceleration αdr_z of the door14being below the predetermined vehicle height acceleration threshold αdr_zth. Not starting driving of the door actuator19unless the acceleration requirements are satisfied can help prevent a situation where the operator may experience a strange feeling as if the door14is moving against their will.

Further, the controller39performs control so that the driving of the door actuator19stops once the opening and closing velocity Vdr of the door14falls below the predetermined velocity threshold Vdrth. Stopping the driving of the door actuator19once the opening and closing velocity Vdr of the door14falls below the predetermined velocity threshold Vdrth can help prevent a situation where the operator may experience a strange feeling as if the door14is coasting against their will.

[Operation of Door Opening and Closing Assisting Apparatus10]

Next, the operation of the door opening and closing assisting apparatus10according to the embodiment of the present invention is described with reference toFIGS.4A,4B, and5as needed.FIG.4Ais a flowchart used to describe the operation of the door opening and closing assisting apparatus10according to the embodiment of the present invention.FIG.4Bis a flowchart illustrating a procedure for a segment of the operation of the door opening and closing assisting apparatus10, the segment being correcting the standard assisting power Psd into the target assisting power Ptg.FIG.5is a diagram conceptually showing how driving control of the door actuator19is started at a timing at which the opening and closing acceleration αdr_y is generated by an opening and closing operation of the door14.

The following premises are made: the door14of the vehicle11is open and located at a door position Odr1, the door14is positioned upward (for example, the right door of the vehicle11that is tilted leftward), and the vehicle11has a front rising attitude (directed in the climbing direction on a slope). An operator starts an operation of opening the door14with the opening and closing velocity Vdr of the door14being equal to or above the predetermined velocity threshold Vdrth.

In Step S11shown inFIG.4A, the information obtainer33belonging to the door ECU28obtains chronological information on the opening and closing velocity Vdr and the openness degree Odr of the door14based on output signals from the Hall sensor31as well as chronological information on the front-back tilt angle Afb and the left-right tilt angle Alr and chronological information on the opening and closing acceleration αdr_y and the vehicle height acceleration αdr_z of the door14based on output signals from the acceleration sensor32.

In Step S12, the determiner35belonging to the door ECU28determines whether the opening and closing acceleration αdr_y of the door14is above a predetermined opening and closing acceleration threshold αdr_yth.

If it is determined in Step S12that the opening and closing acceleration αdr_y of the door14is not above the predetermined opening and closing acceleration threshold αdr_yth (No in Step S12), the door ECU28returns to the start of the processing to repeat the subsequent processing sequentially.

Meanwhile, if it is determined in Step S12that the opening and closing acceleration αdr_y of the door14is above the predetermined opening and closing acceleration threshold αdr_yth (Yes in Step S12), the door ECU28proceeds to the next Step S13.

In the example shown inFIG.5, at a point where the door14reaches a door openness degree Odr2, the opening and closing acceleration αdr_y of the door14is above the predetermined opening and closing acceleration threshold αdr_yth. Thus, the door ECU28proceeds to the next Step S13. Note that in the example shown inFIG.5, at the point where the door14reaches the door openness degree Odr2, the vehicle height acceleration αdr_z of the door14is also within a predetermined vehicle height acceleration threshold |αdz_yth|.

In Step S13, the determiner35belonging to the door ECU28determines whether the opening and closing velocity Vdr of the door14is below a predetermined velocity threshold Vdrth.

If it is determined in Step S13that the opening and closing velocity Vdr of the door14is equal to or above the predetermined velocity threshold Vdrth, the door ECU28proceeds to the next Step S14.

Meanwhile, if it is determined in Step S13that the opening and closing velocity Vdr of the door14is below the predetermined velocity threshold Vdrth, the door ECU28jumps to Step S17.

The example shown inFIG.5satisfies the prerequisite (the operation of opening the door14is started with the opening and closing velocity Vdr of the door14being equal to or above the predetermined velocity threshold Vdrth). Thus, the door ECU28proceeds to Step S14.

In Step S14, based on the opening and closing velocity Vdr of the door14obtained by the information obtainer33, the standard assisting power calculator41of the target assisting power computer37belonging to the door ECU28calculates a standard assisting power Psd which is assisting power required to maintain the opening and closing velocity Vdr.

In a subroutine SUB, the corrector43of the target assisting power computer37belonging to the door ECU28corrects the standard assisting power Psd based on the front-back tilt angle Afb, the left-right tilt angle Alr, the door openness degree Odr, and a predetermined rule.

Now, the subroutine SUB is described with reference toFIG.4B.

In Step S21in the subroutine SUB shown inFIG.4B, the determiner35belonging to the door ECU28determines whether the front-back tilt angle Afb of the vehicle11is above a predetermined front-back tilt angle threshold Afbth.

If it is determined in Step S21that the front-back tilt angle Afb of the vehicle11is above the predetermined front-back tilt angle threshold Afbth (Yes in Step S21), the door ECU28proceeds to the next Step S22.

Meanwhile, if it is determined in Step S21that the front-back tilt angle Afb of the vehicle11is not above the predetermined front-back tilt angle threshold Afbth (No in Step S21), the door ECU28jumps to Step S23.

In Step S22of the subroutine SUB, the corrector43of the target assisting power computer37belonging to the door ECU28makes a correction by increasing or decreasing the standard assisting power Psd based on the front-back tilt angle Afb and the door openness degree Odr.

Considering the premises (the door14of the vehicle11is operated to be open, the door14is positioned upward, and the vehicle11has a front rising attitude), the corrector43makes the correction by increasing the standard assisting power Psd based on the front-back tilt angle Afb and the door openness degree Odr.

In Step S23of the subroutine SUB, the determiner35belonging to the door ECU28determines whether the left-right tilt angle Alr of the vehicle11is above a predetermined left-right tilt angle threshold Alrth.

If it is determined in Step S23that the left-right tilt angle Alr of the vehicle11is above the predetermined left-right tilt angle threshold Alrth (Yes in Step S23), the door ECU28proceeds to the next Step S24.

Meanwhile, if it is determined in Step S23that the left-right tilt angle Alr of the vehicle11is not above the predetermined left-right tilt angle threshold Alrth (No in Step S23), the door ECU28jumps to Step S25.

In Step S24of the subroutine SUB, the corrector43of the target assisting power computer37belonging to the door ECU28makes a correction by increasing or decreasing the standard assisting power Psd based on the left-right tilt angle Alr and the door openness degree Odr.

Considering the premises (the door14of the vehicle11is operated to be open, the door14is positioned upward, and the vehicle11has a front rising attitude), the corrector43makes the correction by increasing the standard assisting power Psd based on the left-right tilt angle Alr and the door openness degree Odr.

In Step S25of the subroutine SUB, the corrector43of the target assisting power computer37belonging to the door ECU28makes a correction by decreasing the standard assisting power Psd based on a predetermined rule.

Then, the door ECU28returns to the main routine shown inFIG.4A. The following continues the description of the main routine.

In Step S15shown inFIG.4A, the target assisting power computer37belonging to the door ECU28sets the standard assisting power Psd which has been corrected in the subroutine SUB, as the target assisting power Ptg. In the present embodiment, the target assisting power computer37sets the standard assisting power Psd corrected taking the above-described premises into account as the target assisting power Ptg.

In Step S16, the controller39belonging to the door ECU28performs driving control for the door actuator19based on the target assisting power Ptg, which is a computation result obtained by the target assisting power computer37(see the OPEN operation of the door motor and an output signal from the Hall sensor31at a door openness degree beyond the openness degree Odr2 shown inFIG.5).

Consequently, favorable operability for opening and closing the door14can be achieved with a simple apparatus configuration.

After the processing in Step S16ends, the door ECU28returns to Step S11and repeats the subsequent processing.

When the opening and closing velocity Vdr of the door14falls below the predetermined velocity threshold Vdrth, in Step S17, the controller39belonging to the door ECU28performs control to stop driving of the door actuator19.

Stopping driving of the door actuator19once the opening and closing velocity Vdr of the door14falls below the predetermined velocity threshold Vdrth can help prevent a situation where the operator may experience a strange feeling as if the door14is coasting against their will.

After the processing in Step S17ends, the door ECU28returns to Step S11and repeats the subsequent processing.

[Advantageous Effects by Door Opening and Closing Assisting Apparatus10]

Next, advantageous effects offered by the door opening and closing assisting apparatus according to the embodiment of the present invention are described.

A door opening and closing assisting apparatus based on a first aspect is on the basis of the door opening and closing assisting apparatus10that assists an opening and closing operation of the door14on the vehicle11.

The door opening and closing assisting apparatus10based on the first aspect includes the information obtainer33that obtains information on the opening and closing acceleration αdr_y of the door14, the door actuator19that performs driving for assisting the opening and closing operation of the door14, the target assisting power computer37that computes the target assisting power Ptg for assisting the opening and closing operation of the door14, and the controller39that performs driving control for the door actuator19based on the target assisting power Ptg.

The controller39is configured to start the driving control for the door actuator19at a timing at which the information obtainer33obtains the opening and closing acceleration αdr_y of the door14.

In the door opening and closing assisting apparatus10based on the first aspect, the controller39starts the driving control for the door actuator19at a timing at which the information obtainer33obtains the opening and closing acceleration αdr_y of the door14. Thus, the door opening and closing assisting apparatus10can start the driving control for the door actuator19by detecting an operator's operation of opening and closing the door14promptly and precisely.

The door opening and closing assisting apparatus10based on the first aspect can start the driving control for the door actuator19by detecting an operator's operation of opening or closing the door14promptly and precisely. Also, in a case where the direction of the opening and closing operation of the door14is inverted, the driving control for the door actuator19can be started by detecting the timing of the inversion promptly and precisely through the opening and closing acceleration αdr_y of the door14.

Thus, favorable operability that does not make the operator feel the weight of the door14when performing the opening and closing operation can be achieved with a simple apparatus configuration.

In addition, a door opening and closing assisting apparatus10based on a second aspect is the door opening and closing assisting apparatus10based on the first aspect, which may be configured as follows: the door is a swing door14that opens and closes, pivotally supported by the hinge mechanisms13A and13B provided on the vehicle body20of the vehicle11, the door opening and closing assisting apparatus10further includes the acceleration sensor32that is provided on the door14and that detects the opening and closing acceleration αdr_y of the door14and the vehicle height acceleration αdr_z of the door14which is an acceleration in the vehicle height direction and the determiner35that determines the magnitudes of the opening and closing acceleration αdr_y and the vehicle height acceleration αdr_z of the door14, the information obtainer33further obtains information on the vehicle height acceleration αdr_z of the door14, and the controller39starts the driving control for the door actuator19at a timing at which the determiner35determines that the opening and closing acceleration αdr_y of the door14is above the predetermined opening and closing acceleration threshold αdr_yth and also the vehicle height acceleration αdr_z of the door14is below the predetermined vehicle height acceleration threshold αdr_zth.

Even when the opening and closing acceleration αdr_y of the door14is above the predetermined opening and closing acceleration threshold αdr_yth, if the vehicle height acceleration αdr_z of the door14is equal to or above the predetermined vehicle height acceleration threshold αdr_zth, it is probable that not an operator's opening and closing operation, but an external perturbation, such as shaking of the vehicle body20as a whole, has been detected. If the door actuator19is started to be driven in such a case, the operator may experience a strange feeling as if the door14is moving against their will.

Thus, in the door opening and closing assisting apparatus10based on the second aspect, the controller39starts the driving control for the door actuator19at a timing at which the determiner35determines that the opening and closing acceleration αdr_y of the door14is above the predetermined opening and closing acceleration threshold αdr_yth and also that the vehicle height acceleration αdr_z of the door14is below the predetermined vehicle height acceleration threshold αdr_zth.

This helps prevent a situation where the operator may experience a strange feeling as if the door14is moving against their will.

A value set as the predetermined vehicle height acceleration threshold αdr_zth may be any appropriate value (except for zero) indicating that the value of the opening and closing acceleration αdr_y of the door14is not a result of error detection.

According to the door opening and closing assisting apparatus10based on the second aspect, the controller39starts controlling driving of the door actuator19at a timing at which the determiner35determines that the opening and closing acceleration αdr_y of the door14is above the predetermined opening and closing acceleration threshold αdr_yth and also that the vehicle height acceleration αdr_z of the door14is below the predetermined vehicle height acceleration threshold αdr_zth. This can help prevent a situation where the operator may experience a strange feeling as if the door14is moving against their will.

Thus, as is similar to the door opening and closing assisting apparatus10based on the first aspect, favorable operability that does not make the operator feel the weight of the door14when performing the opening and closing operation can be achieved with a simple apparatus configuration.

Further, a door opening and closing assisting apparatus10based on a third aspect is the door opening and closing assisting apparatus10based on the first or second aspect, which may be configured as follows: the information obtainer33further obtains information on the opening and closing velocity Vdr of the door14, and the target assisting power computer37calculates, based on the opening and closing velocity Vdr of the door14obtained by the information obtainer33, the standard assisting power Psd which is assisting power required to maintain the opening and closing velocity Vdr, makes a correction by decreasing the calculated standard assisting power Psd according to a predetermined rule, and sets the standard assisting power Psd thus corrected by being decreased, as the target assisting power Ptg.

In the door opening and closing assisting apparatus10based on the third aspect, the target assisting power computer37calculates, based on the opening and closing velocity Vdr of the door14obtained by the information obtainer33, the standard assisting power Psd which is assisting power required to maintain the opening and closing velocity Vdr, makes a correction by decreasing the calculated standard assisting power Psd according to a predetermined rule, and sets the standard assisting power Psd thus corrected by being decreased as the target assisting power Ptg. An occupant, when performing an operation of opening and closing the door14, can actually feel, with a certain response, that the door14is opened and closed in accordance with their will because of the assisting power having a moderate magnitude as a result of a decrease correction.

In the door opening and closing assisting apparatus10based on the third aspect, the standard assisting power Psd is calculated based on the opening and closing velocity Vdr of the door14, a correction is made by decreasing the calculated standard assisting power Psd according to a predetermined rule, and the standard assisting power Psd thus decreased and corrected is set as the target assisting power Ptg. Accordingly, favorable operability that does not make the operator feel the weight of the door14when performing the opening and closing operation can be achieved with a simple apparatus configuration, as is similar to the door opening and closing assisting apparatus10based on the first or second aspect.

Also, a door opening and closing assisting apparatus10based on a fourth aspect is the door opening and closing assisting apparatus10based on the third aspect, which may be configured as follows: the door is a swing door14that opens and closes, pivotally supported by the hinge mechanisms13A and13B provided on the vehicle body20of the vehicle11, the door opening and closing assisting apparatus10further includes the acceleration sensor32that is provided on the door14to detect accelerations in three-dimensional directions including the vehicle length direction, the vehicle width direction, and the vehicle height direction, the information obtainer33further obtains, based on the accelerations in the three-dimensional directions detected by the acceleration sensor32, information on the attitude of the vehicle11including front-back and left-right tilts, and the target assisting power computer37pre-stores information on the attitude of the vehicle11when the door14is fully closed, and when the door14is open, makes a correction to make the target assisting power Ptg larger or smaller based on the pre-stored attitude of the vehicle11.

In a case where the acceleration sensor32is provided on the door14and information on the attitude of the vehicle11is obtained based on information detected by the acceleration sensor32, the attitude of the vehicle11may have error depending on the open or close position of the door14.

In this regard, the door opening and closing assisting apparatus10based on the fourth aspect pre-stores information on the attitude of the vehicle11when the door14is fully closed, and when the door14is open, makes a correction to make the target assisting power Ptg larger or smaller based on the pre-stored attitude of the vehicle11. Thus, information on the attitude of the vehicle11can be obtained with high precision irrespective of the open/close position of the door14.

Also, because the target assisting power computer37makes a correction to make the target assisting power Ptg larger or smaller based on the precise attitude of the vehicle11, even if the attitude of the vehicle11changes, the affect that this attitude change has on the operability for opening and closing the door14can be reduced properly.

Also, a door opening and closing assisting apparatus10based on a fifth aspect is the door opening and closing assisting apparatus10based on the fourth aspect, which may be configured as follows: the door opening and closing assisting apparatus10further includes the Hall sensor (openness degree sensor)31provided on the door actuator19to detect the openness degree Odr of the door14, the information obtainer33further obtains information on the openness degree Odr of the door14via the Hall sensor (openness degree sensor)31, and the target assisting power computer37makes a correction to make the target assisting power Ptg larger or smaller based on the attitude of the vehicle11and the openness degree Odr of the door14.

According to the door opening and closing assisting apparatus10based on the fifth aspect in which the target assisting power computer37makes a correction by increasing or decreasing the standard assisting power Psd based on the attitude of the vehicle11and the openness degree Odr of the door14. Thus, even if the attitude of the vehicle11changes, the affect that this attitude change has on the operability for opening and closing the door14can be reduced properly, and also, the affect that the openness degree Odr of the door14at that time has on the operability for opening or closing the door14can be reduced.

As a result, operability for opening and closing the door14can be made to be even more favorable.

Other Embodiments

A plurality of embodiments described above show examples of how the present invention is embodied. Thus, those embodiments should not be interpreted as limiting the technical scope of the present invention. The present invention can be carried out in various modes without departing from the gist thereof or main features thereof.