Method for adjusting a force that has to be applied by a user to operate a lid

Abstract

The invention relates to an operational force support device that is adapted to support a user when operating a lid (10). The invention further relates to a method for adjusting a force (F.sub.H) that has to be applied by a user to operate a lid (10). Furthermore, the invention relates to a computer module adapted to output an amplification factor and/or an armature voltage that is/are used in the method according to the invention.

Claims

1. An operational force support device, comprising: an actuator that comprises a drive unit, a lid that the actuator is coupled to, and a unit to which the lid is linked in a movable manner, and wherein the actuator is adapted to actuate the lid with respect to the unit to which the lid is linked; a detection unit that the actuator is connected to and that is adapted to detect a speed of the drive unit of the actuator, while the lid is manually operated, and an angle that the lid is situated in with respect to the unit to which the lid is linked; a determination unit that the detection unit is connected to and that is adapted to determine an armature voltage, at which the drive unit of the actuator shall be actuated, in dependence on the speed of the drive unit of the actuator and the angle of the lid with respect to the unit that the lid is linked to and to determine an amplification factor in dependence on the speed of the drive unit of the actuator and the angle of the lid with respect to the unit that the lid is linked to, based on which the armature voltage is determined; and an output unit that is connected to the determination unit and that is adapted to output the armature voltage to the drive unit of the actuator such that the drive unit of the actuator generates a supporting torque depending on the armature voltage, wherein the armature voltage is determined using the formula u.sub.A=i*R+K*θ*n.sub.M, wherein u.sub.A is the armature voltage, i is an applied current, R is a resistance of an electric system of the actuator, K is the amplification factor, θ is a moment of inertia, and n.sub.M is a manual speed of the drive unit applied by a user to move the lid, and wherein the actuator is a linear spindle drive.

2. The operational force support device according to claim 1, wherein the supporting torque generated by the drive unit of the actuator is below a torque that is necessary to move the lid at the detected speed solely by the drive unit of the actuator.

3. The operational force support device according to claim 1, wherein the operational force support device further comprises: a temperature sensor adapted to detect a temperature in a vicinity of the actuator, or an inclination sensor adapted to detect an angle that the unit to which the lid is linked is situated in with respect to a gravity direction.

4. The operational force support device according to claim 1, wherein the operational force support device further comprises a storage unit in which a look-up table is stored comprising specific values of armature voltages and/or amplification factors in dependence on at least the angle of the lid with respect to the unit to which the lid is linked.

5. A method for adjusting a force that has to be applied by a user to operate a lid, wherein an actuator that is adapted to actuate the lid is coupled to the lid, wherein the method comprises: providing the lid, on which the actuator is disposed; detecting a speed of a drive unit of the actuator, while the lid is manually operated, and an angle that the lid is situated in with respect to a unit to which the lid is linked; determining an amplification factor in dependence on the speed of the drive unit of the actuator and the angle of the lid with respect to the unit to which the lid is linked; determining an armature voltage at which the drive unit of the actuator shall be actuated; and outputting the armature voltage to the drive unit of the actuator such that the drive unit of the actuator generates a supporting torque depending on the armature voltage, wherein the armature voltage is determined using the formula u.sub.A=i*R+K*θ*n.sub.M, wherein u.sub.A is the armature voltage, i is an applied current, R is a resistance of an electric system of the actuator, K is the amplification factor, θ is a moment of inertia, and n.sub.M is a manual speed of the drive unit applied by a user to move the lid, and wherein the actuator is a linear spindle drive.

6. The method according to claim 5, wherein the supporting torque generated by the drive unit of the actuator is below a torque that is necessary to move the lid at the detected speed solely by the drive unit of the actuator.

7. The method according to claim 5, wherein the method further comprises detecting an angle that the unit to which the lid is connected to is situated in with respect to a gravity direction.

8. The method according to claim 5, wherein the method further comprises detecting a temperature in a vicinity of the actuator.

9. The method according to claim 5, wherein determining the amplification factor comprises selecting a value from a look-up table in dependence on at least the angle of the lid with respect to the unit to which the lid is linked.

10. The method according to claim 5, wherein determining the armature voltage at which the drive unit of the actuator shall be actuated comprises selecting a value from a look-up table in dependence on at least the speed of the drive unit of the actuator and the amplification factor.

11. The method according to claim 5, wherein the amplification factor or the armature voltage is selected based on a presetting that defines a specific operation force in dependence on at least the angle of the lid.

12. The method according to claim 5, wherein the lid is a trunk lid of a vehicle adapted to grant or prevent access to a trunk of the vehicle.

Description

(1) In the following the present invention will be described with respect to the attached drawings, in which:

(2) FIG. 1 shows a rear part of a vehicle including applied forces and leverages;

(3) FIG. 2 shows a plurality of graphical curves of operational forces in dependence of angles of the lid;

(4) FIG. 3 shows a diagram illustrating the correlation of speed of a drive unit of an actuator, armature voltage and generated torque.

(5) In FIG. 1 a trunk lid 10 is articulated on a vehicle body 12 at a pivot point 14. At the center of gravity of the lid 10 a gravity force F.sub.G is applied to the lid 10 with a leverage I.sub.FG of the gravity force F.sub.G to the pivot point 14.

(6) An actuator 16 is coupled on its one end to the lid 10 and to the vehicle body 12 on its other end. In FIG. 1 only one actuator 16 is shown but it is to be understood that a second actuator may be disposed on the other longitudinal side of the vehicle body 12. Of course, in case of a plurality of actuators, the supporting forces have to be distributed to the actuators accordingly. A leverage of the coupling point of the actuator 16 at the lid 10 to the pivot point 14 is described by the distance I.sub.SD.

(7) An angle of the lid 10 with respect to the vehicle body 12 is denoted in FIG. 1 by an angle α.

(8) Furthermore, a force F.sub.H that has to be applied by a user in order to move the lid 10 with respect to the vehicle body 12 is shown at a handle point 18 at the lid 10. The distance of the handle point 18 to the pivot point 14 is indicated by the radius R.sub.FH.

(9) When a user moves the lid 10 in the direction of the arrow F.sub.H at the handle point 18 of the lid 10, the actuator 16, which is a linear spindle drive in the shown embodiment, is reduced in length. This results in a rotation of a spindle or a spindle nut, whichever is driven by the drive unit of the spindle drive, and therefore in a passive activation of the drive unit, e.g. in a rotation of a drive shaft of an electric motor. A speed n generated in the drive unit, i.e. here in the electric motor, is detected by a detection unit 20. The detection unit 20 also detects the angle α of the lid 10 with respect to the vehicle body 12, e.g. by using corresponding sensors.

(10) The detected speed n of the drive unit of the actuator and the detected angle α of the lid 10 are forwarded to a determination unit 22 that is adapted to determine an armature voltage u.sub.A at which the drive unit of the actuator shall be actuated in dependence of the speed n of the drive unit of the actuator and the angle α of the lid 10. The determination unit 22 may also determine an amplification factor K based on which the armature voltage u.sub.A is determined using the formula
u.sub.A=i*R+K*θ*n.sub.M  (1)

(11) Wherein i is the current applied, R is the resistance of the electric system, θ is the moment of inertia, and n.sub.M is the manual speed of the drive unit that a user shall apply to the lid to move it.

(12) The determination unit 22 may comprise a look-up table including a presetting of values of manual operational forces F.sub.H in dependence on angles α of the lid 10 with respect to the vehicle body 12. This presetting may comprise a graphical curve indicating a manual operational force F.sub.H for each angle α of the lid 10. A plurality of possible examples of such graphical curves is shown in FIG. 2, wherein the X-axis shows the angle α of the lid 10 (called “opening angle tailgate” in FIG. 2) given in degrees and the Y-axis shows the manual operational force F.sub.H (denoted by “handle effort” in FIG. 2) given in Newton.

(13) When a specific manual operational force F.sub.H is selected in dependence on a specific situation, an output unit 24 outputs the armature voltage u.sub.A to the drive unit of the actuator 16 such that the drive unit of the actuator 16 generates a supporting torque M depending on the armature voltage u.sub.A.

(14) Changing the armature voltage u.sub.A at a constant speed n of the drive unit of the actuator 16, e.g. increasing it, results in a changed, e.g. increased, torque M of the actuator 16.

(15) The dependence of the speed of the drive unit of the actuator 16 on the armature voltage u.sub.A resulting in a specific torque M is shown in FIG. 3. The X-axis describes the speed n of the drive unit of the actuator 16 and the Y-axis describes the torque M generated by the actuator 16. The inclined lines running from upper left to lower right of the diagram show different motor characteristics at different armature voltages u.sub.1 (lower/left dashed line), u.sub.2 (solid line) and u.sub.3 (upper/right dashed line), wherein u.sub.1<u.sub.2<u.sub.3.

(16) The arrow pointing from the motor characteristic of u.sub.1 to the motor characteristic of u.sub.3 indicates that increasing the armature voltage u.sub.A at a constant speed n of the drive unit of the actuator 16 results in an increased torque M.

(17) As a result, the supporting forces generated by the actuator 16 according to the present invention may be increased or reduced by increasing or reducing an armature voltage u.sub.A at the drive unit of the actuator 16, as desired.