Coordinative control method for the back and knee bottom sections of a bed or the like

Abstract

A coordinative control method for the back and knee bottom sections of a bed or the like, characterized in that when the back bottom section and the knee bottom section are operated in a coordinative manner, the back bottom section or the knee bottom section is actuated for adaptation to ensure that an action can be carried out based on a preset action pattern starting from the present state of positions.

Description

[0001] This is a Continuation-In-Part application of application Ser. No. 10/389,960, filed Mar. 18, 2003.

FIELD OF THE INVENTION

[0002] The present invention relates to a coordinative control method for the back and knee bottom sections of a bed or the like, for example, having back and knee lifting functions, for adaptation from the present state of positions of the bottom sections of the bed or the like, to a predetermined action of the back and knee bottom sections in a coordinative manner.

BACKGROUND OF THE INVENTION

[0003] In recent years, among beds and the like such as medical beds and general (long term care) beds, many beds allowing positional adjustment of its bottom sections (allowing its bottom sections to be lifted for back lifting, knee lifting, etc.) are commercially available, and they are designed to act for back lifting and lowering and knee lifting and lowering based on various action patterns.

PROBLEM OF THE PRIOR ART

[0004] When the positions of bottom sections of a bed are adjusted, the adjustment does not always start from the initial state where the bottom sections lie flat. Actually it is often practiced to start adjustment from a state where the back bottom section and the knee bottom section are adjusted at certain positions, for achieving a desired state of positions. So, for letting the back bottom section and the knee bottom section act according to a predetermined action pattern starting from said adjusted positions, it is necessary to quickly adapt their adjusted positions to the action pattern.

[0005] U.S. Pat. No. 6,460,209 discloses a control means is provided as a storing means for storing preferred positions of the back bottom member and knee bottom member, so that the back and knee bottom members can be controlled to travel to the positions stored in the storing means. However, what is stored in the storing means is only the final positions at which the back bottom member and the knee bottom member are inclined after having been controlled by the control means. The continuous positions and path which the back bottom member and the knee bottom member are to pass before they reach the final positions are not stored in the control means. This is illustrated in FIGS. 11 and 12 together with the path of travel when the controller directs movement of the back bottom members to a desired final position.

[0006] This invention is proposed to solve these problems. The object of this invention is to provide a coordinative control method for the back and knee bottom sections of a bed or the like having back lifting and knee lifting functions, for letting the back and knee bottom sections carry out a predetermined action in a coordinative manner from any arbitrarily lifted and lowered positions of the bottom sections.

SUMMARY OF THE INVENTION

[0007] To solve the above-mentioned problem, in this invention, there is disclosed a coordinative control method for the back and knee bottom sections of a bed or the like, characterized in that when the back bottom section and the knee bottom section are operated in a coordinative manner, the back bottom section or the knee bottom section is actuated for adaptation to ensure that an action can be carried out based on a preset action pattern starting from the present state of positions.

[0008] The correlation between the back bottom section and the knee bottom sections of the bed lifted and lowered under coordinative operation can be expressed as a correlative action curve on a two-dimensional space in which the inclination angle of the back bottom member is chosen as one axis while the inclination angle of the knee bottom member is chosen as the other axis perpendicular to said one axis, as shown in the attached FIGS. 9 and 10. The back bottom sections and the knee bottom sections of the bed are lifted and lowered under coordinative operation to follow the correlative action curve.

[0009] The bed can be quickly corrected to follow the correlative action curve, as shown in FIG. 10. That is, in the present invention, the back bottom sections and the knee bottom sections can be lifted and lowered under coordinative operation to reach the intended final inclination positions. In this case, the continuous positions of the back bottom section and the knee bottom sections in the process of reaching the final positions are also stored in the storing means of a control means as the correlative action curve.

[0010] Furthermore, in this invention, there is disclosed a coordinative control method for the back and knee bottom sections of a bed or the like, characterized in that when the back bottom section and the knee bottom section are operated in a coordinative manner starting from the present state of positions of the bottom of the bed or the like, the knee bottom section is controlled to form the knee lifting angle of the knee bottom section corresponding to the back lifting angle of a preset action pattern, for adaptation to said action pattern.

[0011] Still furthermore, in this invention, there is disclosed a coordinative control method for the back and knee bottom sections of a bed or the like, characterized in that when the back bottom section and the knee bottom section are operated in a coordinative manner starting from the present state of positions of the bottom of the bed or the like, the back bottom section and the knee bottom section are controlled to aim at the nearest action change point of the knee bottom section on a preset action pattern, in order to let the bottom sections act based on said action pattern.

[0012] In this invention, the bed or the like includes a hospital bed, stretcher, ICU bed or a long term care bed.

[0013] Irrespective of the present state of positions of the bottom sections, a desired adjusted state can be achieved.

[0014] In another aspect of the invention, the back bottom section and the knee bottom section can be quickly brought to the positions corresponding to a predetermined action pattern, and the bottom sections can be adjusted to desired positions according to the action pattern.

[0015] Accordingly, a position control map can be simple.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a typical side view showing an example of the long term care bed to which the coordinative control method for the back and knee bottom sections of a bed or the like of this invention is applied

[0017] FIG. 2 is a position control map for illustrating a method of adapting to a back lifting action pattern in the coordinative control method for the back and knee bottom sections of a bed or the like of this invention.

[0018] FIG. 3 is a side view of bottom sections for illustrating knee lifting

[0019] FIG. 4 is a side view of bottom sections for illustrating back lifting started together with knee lifting

[0020] FIG. 5 is a side view of bottom sections for illustrating the continuation of back lifting, with knee lifting stopped

[0021] FIG. 6 is a side view of bottom sections for illustrating the continuation of back lifting, with knee lifting started

[0022] FIG. 7 is a side view of bottom sections illustrating completion of back lifting

[0023] FIG. 8 is a position control map for illustrating the adaptation to a back lifting action pattern, in the coordinative control method for the back and knee bottom sections of a bed or the like of this invention.

[0024] FIG. 9 is a position control map illustrating a method of coordinative control for back and knee bottom sections of a bed according to the present invention.

[0025] FIG. 10 is a position control map illustrating a desired correlative action curve and a correction movement of the back and knee bottom sections of a bed when the existing positions of the back and knee bottom sections at the start of the method is not on the corrective action curve.

[0026] FIG. 11 is a position control map illustrating how the prior art stores desired positions of bottom members of a bed merely as a correlative point.

[0027] FIG. 12 is a position control map illustrating the path of the bottom members in the prior art when only the final positions of the back and knee bottom members is stored in a control means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] For the coordinative control method for the back and knee bottom sections of a bed or the like of this invention, one embodiment is described based on the attached drawings.

[0029] The bottom 1 of a bed apparatus shown in FIG. 1 is divided into a back bottom section 1a corresponding to the back, a knee bottom section 1b corresponding to the region from the waist to the knees and the leg bottom section 1c corresponding to the legs, and though not illustrated, a back lifting link as a back lifting mechanism abuts the back side of said back bottom section 1a, while a knee lifting link as a knee lifting mechanism is attached to the back side of the knee bottom section 1b for lifting and lowering the knee bottom section 1b and the leg bottom section 1c in a coordinative manner. The back lifting link and the knee lifting link are respectively connected to drive means (not illustrated), for allowing back lifting and knee lifting.

[0030] For each of said drive means, for example, an electric directly acting drive mechanism (not illustrated) can be applied. Remote control switches or control switches (not illustrated) on a control panel to be operated by an attendant, nurse or the like are operated to give control commands for back lifting, knee lifting and gatch action (concurrent back lifting and knee lifting), so that electric power is supplied from a controller mounted on a control box installed at a frame or the like of the bed, to start the respective directly acting drive mechanisms, for adjusting to desired positions.

[0031] Said controller starts and stops the supply of electric power to the directly acting drive mechanisms such as motors for actuating the back lifting mechanism and the knee lifting mechanism based on the signals given from said remote control switches or the control switches of the control panel, and has, for example, a back lifting action control procedure of the action pattern shown by a thick solid like in FIG. 2 and FIG. 9 preset in it. The motors as the directly acting drive mechanisms for actuating said back lifting mechanism and knee lifting mechanism is provided, for example, with rotation quantity detecting means as means for obtaining the position information of the back bottom section 1a and the knee bottom section 1b.

[0032] Control commands are given to carry out a back lifting action procedure in FIG. 2 as follows: (i) knee lifting started (knee lifting motor turned on for normal rotation), (ii) back lifting started (back lifting motor turned on for normal rotation) after lapse of time t (knee lifting angle 15 degrees), (iii) knee lifting stopped (knee lifting motor turned off) after lapse of predetermined time (T), with knee lifting angle 30 degrees and back lifting angle 15 degrees, (iv) back lifting continued till reaching back lifting angle 40 degrees, (v) knee lowering started and continued till reaching knee lifting angle 15 degrees (knee lifting motor turned on for reverse rotation), back lifting continued (back lifting angle 55 degrees), (vi) back lifting continued (back lifting angle 60 degrees), (vii) knee lowering continued (knee lifting angle about 0 degree), back lifting continued till reaching back lifting angle about 78 degrees, (viii) back lifting stopped (back lifting motor turned off), knee lowering completed (knee lifting motor turned off)

[0033] For carrying out the above-mentioned back lifting action procedure as in FIG. 2 and FIG. 9, said controller receives the signals detected by the rotation quantity detecting means provided in the motors used as the directly acting drive mechanism for actuating the back lifting mechanism and the knee lifting mechanism, as the position information of the back bottom section 1a and the knee bottom section 1b at the time of starting.

[0034] In response to the position information of bottom sections at the time of starting, the knee lifting motor or the back lifting motor is controlled for adjusting the knee lifting angle or the back lifting angle for adaptation to the aforesaid action pattern.

[0035] That is:

[0036] (1) If the knee lifting angle is 0 to 15 degrees while the back lifting angle is 0 to 15 degrees at the time of starting, then knee lifting is started (the knee lifting motor is turned on for normal rotation).

[0037] (2) If the knee lifting angle is 15 to 30 degrees while the back lifting angle is 0 to 15 degrees at the time of starting, and the back lifting angle is larger than the knee lifting angle of the action pattern, then knee lifting is started (the knee lifting motor is turned on for normal rotation).

[0038] (3) If the knee lifting angle is 15 to 30 degrees while the back lifting angle is 0 to 15 degrees at the time of starting, and the back lifting angle is smaller than the knee lifting angle of the action pattern, then back lifting is started (the back lifting motor is turned on for normal rotation).

[0039] (4) If the knee lifting angle is 0 to 30 degrees while the back lifting angle is 15 to 40 degrees at the time of starting, then knee lifting is started (the knee lifting motor is turned on for normal rotation).

[0040] (5) If the knee lifting angle is 0 to 15 degrees while the back lifting angle is 40 to 65 degrees at the time of starting, then back lifting is started (the back lifting motor is turned on for normal rotation).

[0041] (6) If the knee lifting angle is 15 to 30 degrees while the back lifting angle is 40 to 55 degrees at the time of starting, and the back lifting angle is smaller than the knee lifting angle of the action pattern, then back lifting is started (the back lifting motor is turned on for normal rotation).

[0042] (7) If the knee lifting angle is 15 to 30 degrees while the back lifting angle is 40 to 55 degrees at the time of starting, and the back lifting angle is larger than the knee lifting angle of the action pattern, then knee lowering is started (the knee lifting motor is turned on for reverse rotation).

[0043] (8) If the knee lifting angle is 15 to 30 degrees while the back lifting angle is 55 to 78 degrees, then knee lowering is started (the knee lifting motor is turned on for reverse rotation).

[0044] (9) If the knee lifting angle is 0 to 20 degrees while the back lifting angle is 65 to 78 degrees, and the back lifting angle is larger than the knee lifting angle of the action pattern, then back lifting is started (the back lifting motor is turned on for normal rotation).

[0045] (10) If the knee lifting angle is 0 to 20 degrees while the back lifting angle is 65 to 78 degrees, and the back lifting angle is smaller than the knee lifting angle of the action pattern, then knee lowering is started (the knee lifting motor is turned on for reverse rotation).

[0046] In the above-mentioned coordinative control method for the back and knee bottom sections of a bed or the like, the action is described below based on the setting procedure.

[0047] In the method of the present invention, the knee bottom section is lifted to prevent a person in the bed from sliding toward the foot of the bed as the back bottom section of the bed is elevated. As the knees and back of a person are raised, the person in the bed may feel pressure as their knees approach their upper body.

[0048] Since the knee lifting angle at which the lying person feels a pressure is different from person to person, the knee lifting angle is preset using a remote control switch or a knee lifting angle setting switch on the control panel.

[0049] The maximum knee lifting angle in FIGS. 2, 8, 9 and 10 corresponds to the point at which a person in the bed may feel pressure as their knees are lifted when their body is being elevated.

[0050] For example, receiving a back lifting start command, the controller can receive the signals detected, for example, by the rotation quantity detecting means installed in the motors used as the directly acting drive mechanisms for actuating the back lifting mechanism and the knee lifting mechanism, as the position information of the back bottom section 1a and the knee bottom section 1b at the time of starting. Then, from the state of the bottom sections at the time of starting, the adaptation procedure shown in any one of (1) through (10) is carried out, and back lifting is carried out according to the action pattern of (i) through (viii).

[0051] Although there is described above a rotation quantity detecting means, any conventional position detecting means can be used to determine and detect the position information of the back and knee bottom sections. Upon receiving the position information from a position detecting means, the controller then compares the present position of the back and knee bottom sections with the preset correlative position control pattern, and then, if the present position deviates from the preset control pattern, the controller can then aim the back and knee bottom sections at the nearest action conversion point of the knee bottom section action pattern.

[0052] If the position information shows that the bottom 1 is in a flat state as shown in FIG. 1, the controller can carry out back lifting according to the action pattern of (i) through (viii) without carrying out any adaptation procedure.

[0053] Furthermore, if the position information shows that the bottom is in a state as shown in FIG. 3 or 4, and "(1) if the knee lifting angle is 0 to 15 degrees while the back lifting angle is 0 to 15 degrees at the time of starting, then knee lifting is started (the knee lifting motor is turned on for normal rotation)," or "(2) if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 0 to 15 degrees at the time of starting, and the back lifting angle is larger than the knee lifting angle of the action pattern, then knee lifting is started (the knee lifting motor is turned on for normal rotation)," or "(3) if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 0 to 15 degrees at the time of starting, and the back lifting angle is smaller than the knee lifting angle of the action pattern, then back lifting is started (the back lifting motor is turned on for normal rotation)," for adapting the knee lifting angle and the back lifting angle to the action pattern, and subsequently back lifting can be carried out according to the action pattern of (ii) through (viii).

[0054] Furthermore, if the position information shows that the bottom 1 is in a state as shown in FIG. 5, and "(4) if the knee lifting angle is 0 to 30 degrees while the back lifting angle is 15 to 40 degrees at the time of starting, then knee lifting is started (the knee lifting motor is turned on for normal rotation)," for adapting the knee lifting and the back lifting angle to the action pattern, and subsequently back lifting is carried out according to the action pattern of (iv) through (viii).

[0055] Still furthermore, if the position information shows that the bottom 1 is in a state as shown in FIG. 6, and "(5) if the knee lifting angle is 0 to 15 degrees while the back lifting angle is 40 to 65 degrees at the time of starting, then back lifting is started (the back lifting motor is turned on for normal rotation), for adapting the knee lifting angle and the back lifting angle to the action pattern, and subsequently, the action is carried out according to (vii) knee lowering continued (knee lifting angle about 0 degree), back lifting continued till reaching back lifting angle about 78 degrees, and (viii) back lifting stopped (back lifting motor turned off), knee lowering completed (knee lifting motor turned off).

[0056] Still furthermore, "(6) if the knee lifting angle is 15 to 30 degrees and the back lifting angle is 40 to 55 degrees at the time of starting, and the back lifting angle is smaller than the knee lifting angle of the action pattern, then back lifting is started (the back lifting motor is turned on for normal rotation)," or "(7) if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 40 to 55 degrees at the time of starting, and the back lifting angle is larger than the knee lifting angle of the action pattern, then knee lowering is started (the knee lifting motor is turned on for reverse rotation)," and subsequently back lifting can be carried out according to the action pattern of (v) through (viii).

[0057] Still furthermore, as shown in FIG. 7 "(8) if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 55 to 78 degrees, then knee lowering is started (the knee lifting motor is turned on for reverse rotation)," or "(9) if the knee lifting angle is 0 to 20 degrees while the back lifting angle is 65 to 78 degrees, and the back lifting angle is larger than the knee lifting angle of the action pattern, then back lifting is started (the back lifting motor is turned on for normal rotation)," or "(10) if the knee lifting angle is 0 to 20 degrees while the back lifting angle is 65 to 78 degrees, and the back lifting angle is smaller than the knee lifting angle of the action pattern, then knee lowering is started (knee lifting motor is turned on for reverse rotation)," for adaptation to the action pattern, and back lifting can be completed.

[0058] As described above, if any of the above-mentioned adaptation procedures applicable to each case is used, the back bottom section 1a and the knee bottom section 1b can be quickly brought to the positions corresponding to a predetermined action pattern, and the bottom 1 can be adjusted to a desired back lifting position according to the action pattern.

[0059] Furthermore, in this invention, in response to the position information of the bottom 1 at the time of starting, the knee lifting motor and the back lifting motor can be controlled to achieve the knee lifting angle or the back lifting angle corresponding to the action pattern for back lifting.

[0060] That is, as shown in FIG. 8, from the position information of the bottom 1 at the time of starting, the back bottom section 1a and the knee bottom section 1b can be controlled to aim at the nearest action conversion point of the knee bottom section 1b on the action pattern.

[0061] The term "action conversion point" refers to a point on the preset correlative position control pattern where the knee bottom section changes direction. The manner in which the knee lifting motor and back lifting motor are controlled to aim at the nearest action change point is described in greater detail hereinafter.

[0062] The controller is preset to control the knee lifting motor and the back lifting motor, to achieve the knee lifting angle or the back lifting angle corresponding to the aforesaid action pattern as described below in response to the position information of the bottom sections at the time of starting.

[0063] That is:

[0064] (1) If the knee lifting angle is 15 to 30 degrees while the back lifting angle is 0 to 15 degrees at the time of starting, and the back lifting angle is smaller than that of the action pattern, then the knee lifting motor and the back lifting motor are adequately controlled to aim at the action change point a (knee lifting angle 30 degrees, back lifting angle 15 degrees).

[0065] (2) If the knee lifting angle is 0 to 30 degrees while the back lifting angle is 0 to 40 degrees, and the back lifting angle is larger than that of the action pattern, then the knee lifting motor and the back lifting motor can be adequately controlled to aim at the action change point .beta. (knee lifting angle 30 degrees, back lifting angle 40 degrees).

[0066] (3) If the knee lifting angle is 15 to 30 degrees while the back lifting angle is 40 to 55 degrees, and the back lifting angle is smaller than that of the action pattern, then the knee lifting motor and the back lifting motor are adequately controlled to aim at the action change point .gamma. (knee lifting angle 30 degrees, back lifting angle 40 degrees).

[0067] (4) If the knee lifting angle is 0 to 15 degrees while the back lifting angle is 40 to 65 degrees, then the knee lifting motor and the back lifting motor are adequately controlled to aim at the action change point 5 (knee lifting angle 15 degrees, back lifting angle 65 degrees).

[0068] (5) If the knee lifting angle is 0 to 30 degrees while the back lifting angle is 40 to 78 degrees, and the back lifting angle is larger than the knee lifting angle of the action pattern, then the knee lifting motor and the back lifting motor are adequately controlled to aim at the action change point .epsilon. (knee lifting angle 0 degree, back lifting angle 78 degrees).

[0069] (6) If the knee lifting angle is 0 to 15 degrees while the back lifting angle is 65 to 78 degrees, and the back lifting angle is smaller than that of the action pattern, the action change point .epsilon. (knee lifting angle 0 degree, back lifting angle 78 degrees) is aimed at.

[0070] As described above, if a back lifting operation command is issued, the back bottom section 1a or the knee bottom section 1b is controlled from the present state of the bottom 1 to aim at any of the nearest action change points .alpha. to .epsilon. on the action pattern, to ensure that the back lifting action can be carried out according to the action pattern of (i) through (viii). So, the adaptation procedure (software) can be more simplified, and the position control map can be simpler.

[0071] FIG. 9 and FIG. 10 show a correlative action curve which the back bottom section and the knee bottom section of the bed follow when they are lifted and lowered under coordinative operation.

[0072] The control means controls the back bottom section and the knee bottom section so that they are lifted in the beginning to follow this correlative action curve. As can be seen from the diagram, FIGS. 9 and 10, the back bottom member ascends merely in one direction and becomes gradually larger in angle. However, the knee bottom member which gradually ascends in the beginning begins to descend after passing a certain predetermined maximum angle. So, the knee bottom section becomes larger in angle in the beginning but becomes gradually smaller in angle after a certain point in time.

[0073] This control cannot be made unless the storing means stores the correlative action curve.

[0074] Furthermore, while the action of FIG. 9 and FIG. 10 is the basic path followed in the present invention, there can be a case where the back bottom section and the knee bottom section deviate from the correlative action curve, as shown in FIG. 10. In preparation for such a case, the present invention proposes how to particularly control them for moving them from the currently existing positions deviating from the correlative action curve, to any correlative point on the correlative action curve.

[0075] The coordinative control method for the back and knee bottom sections of a bed or the like of this invention has been described based on an action pattern for back lifting. However, also in the case of gatch action, the present state of the bottom can be adapted to an action pattern for gatch action.

INDUSTRIAL APPLICABILITY

[0076] As described above, this invention can exhibit the following effects.

[0077] (1) Irrespective of the present positions of bottom sections, they can be adjusted to desired positions.

[0078] (2) The back bottom section and the knee bottom section can be quickly brought to the positions corresponding to a predetermined action pattern, and the bottom sections can be adjusted to desired positions according to the action pattern.

[0079] (3) If a method of adjusting the back and knee bottom sections aiming at the nearest action change point of a preset action pattern, the adaptation procedure can be simplified, and the position control map can be simplified.

Claims

1. A coordinative control method for back and knee bottom sections of a bed using a control means comprising a user control means, a computer programmable storage means having a preset action pattern stored therein, a back lifting mechanism, a knee lifting mechanism and a rotation quantity detecting means, the method comprising: a first step of lifting the knee bottom section to a predetermined angle of about 0 to 30 degrees; a second step of lifting the back bottom section to an angle of about 15 to 65 degrees, the second step being begun after, but during, the first step when the knee bottom section reaches an angle of about 15 degrees; a third step of lowering the knee bottom section to an angle of about 0 to 15 degrees; a fourth step of lifting the back bottom section to an angle of about 55-60 degrees; a fifth step of lowering the knee bottom section to an angle of about 0 degrees; and a sixth step of lifting the back bottom section to an angle of about 60-78 degrees.

2. A coordinative control method for back and knee bottom sections of a bed wherein the back bottom section and knee bottom section are lifted and lowered in a coordinative operation so that an inclination angle of the back and knee bottom sections is controlled to follow a preset correlative position control pattern.

3. A coordinative control method for back and knee bottom sections of a bed wherein when the back and knee bottom sections are to be operated in a coordinative manner starting from any starting position other than a preset correlative position control pattern, the back and knee bottom sections are controlled to aim at a nearest action change point of the knee bottom section on a preset control pattern, in order to let the bottom sections act based on said control pattern.

4. The method of claim 1, wherein, if the knee lifting angle is 0 to 15 degrees while the back lifting angle is 0 to 15 degrees at the time of starting of a back lifting step, then knee lifting is begun.

5. The method of claim 1, wherein, if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 0 to 15 degrees at the time of starting of a back lifting step, and the back lifting angle is larger than a preset knee lifting angle in the respective preset action pattern, then knee lifting is begun.

6. The method of claim 1, wherein, if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 0 to 15 degrees at the time of starting of a back lifting step, and the back lifting angle is smaller than the preset knee lifting angle in the respective preset action pattern, then back lifting is begun.

7. The method of claim 1, wherein, if the knee lifting angle is 0 to 30 degrees while the back lifting angle is 15 to 40 degrees at the time of starting of a back lifting step, then knee lifting is begun.

8. The method of claim 1, wherein, if the knee lifting angle is 0 to 15 degrees while the back lifting angle is 40 to 65 degrees at the time of starting of a back lifting step, then back lifting is begun.

9. The method of claim 1, wherein, if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 40 to 55 degrees at the time of starting of a back lifting step, and the back lifting angle is smaller than the preset knee lifting angle in the respective preset action pattern, then back lifting is begun.

10. The method of claim 1, wherein, if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 40 to 55 degrees at the time of starting of a back lifting step, and the back lifting angle is larger than the preset knee lifting angle in the respective preset action pattern, then a knee lowering step is begun.

11. The method of claim 1, wherein, if the knee lifting angle is 15 to 30 degrees while the back lifting angle is 55 to 78 degrees, then knee lowering is begun.

12. The method of claim 1, wherein, if the knee lifting angle is 0 to 20 degrees while the back lifting angle is 65 to 78 degrees, and the back lifting angle is larger than the preset knee lifting angle of the respective preset action pattern, then back lifting is begun.

13. The method of claim 1, wherein, if the knee lifting angle is 0 to 20 degrees while the back lifting angle is 65 to 78 degrees, and the back lifting angle is smaller than the preset knee lifting angle of the respective preset action pattern, then knee lowering is begun.

14. The coordinative control method of claim 2, wherein the preset correlative position control pattern is stored in a control means.

15. The coordinative control method of claim 2, wherein a preset correlative position control pattern corresponds to a pattern as in FIG. 9.

16. the coordinative control method of claim 14, wherein the control means stores a control pattern as in FIG. 9.

17. The coordinative control method of claim 3, wherein a starting position of the back and knee bottom sections is first detected by a position detecting means.

18. The coordinative control method of claim 17, wherein a control means compares the starting position information from the position detecting means with a preset correlative position control pattern stored in the control means to determine if the starting position corresponds to any point on the preset correlative position control pattern.

19. The coordinative control method of claim 18, wherein the control means aims the back and knee bottom sections at a nearest action conversion point of a knee bottom section action pattern.

20. The coordinative control method of claim 3, wherein the preset correlative position control pattern corresponds to a pattern as in FIG. 9.