Gravity compensation control system and method using multiple feasibility parameters

• US 20040249319A1
• Filed: 04/13/2004
• Published: 12/09/2004
• Est. Priority Date: 09/23/2002
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Dariush, Behzad
• Granted Patent: US 7,390,309 B2
• Time in Patent Office: Days
• US Class Current: 601/5
• CPC Class Codes: A61H 1/00 Apparatus for passive exercising A61H5/00 takes precedence; Vibrating apparatus driving means for vibrating A61H23/00; Chiropractic devices, e.g. body impacting devices, external devices for briefly extending or aligning unbroken bones
• CPC Class Codes: A61H 1/024 Knee A61H1/0255 takes precedence
• CPC Class Codes: A61H 1/0244 Hip A61H1/0255 takes precedence
• CPC Class Codes: A61H 1/0255 Both knee and hip of a patient, e.g. in supine or sitting position, the feet being moved in a plane substantially parallel to the body-symmetrical-plane A61H1/0214 takes precedence
• CPC Class Codes: A61H 1/0266 Foot
• CPC Class Codes: A61H 2001/0211 Walking coordination of arms and legs
• CPC Class Codes: A61H 2201/1215 Rotary drive
• CPC Class Codes: A61H 2201/165 Wearable interfaces
• CPC Class Codes: A61H 2201/1676 Pivoting
• CPC Class Codes: A61H 2201/5007 computer controlled
• CPC Class Codes: A61H 2201/5061 Force sensors
• CPC Class Codes: A61H 2201/5069 Angle sensors
• CPC Class Codes: A61H 3/00 Appliances for aiding patients or disabled persons to walk about apparatus for helping babies to walk A47D13/04; orthopaedic devices for correcting deformities of, or supporting, limbs A61F5/0102; exercising apparatus for the feet or toes A63B23/10; stairways or ramps E04F11/00
• CPC Class Codes: A61H 3/008 Using suspension devices for supporting the body in an upright walking or standing position, e.g. harnesses drawing-out devices A61H1/0218
• CPC Class Codes: A63B 21/00181 comprising additional means assisting the user to overcome part of the resisting force, i.e. assisted-active exercising
• CPC Class Codes: B25J 9/0006 Exoskeletons, i.e. resembling a human figure

Abstract

A method for obtaining an assist torque to be applied to a human joint, in a human assist system in order to reduce load on muscles, according to the present invention comprises the step of obtaining a moment due to gravity, acting on a joint of each human segment, based on equations of force and moment balance on each segment. The method further comprises the step of obtaining an assist torque to be applied to the joint to compensate for the moment due to gravity, acting on the joint. In one embodiment of the present invention, various criteria are used such a mechanical energy, metabolic energy and/or a stability/equilibrium factor. In addition, the present invention can account for the situation when there is substantially no relative motion between segments of a given joint and thus, where the mechanical energy component of gravity compensation is approximately zero.

Claims

1. A method for obtaining an assist torque to be applied to a human joint, in a human assist system for applying an assist torque to the human joint, comprising the steps of:

determining a gravity compensation control torque value for a first joint;

identifying said gravity compensation control torque as being feasible if the relative angular velocity between first and second segment of said first joint is substantially zero; and

identifying a gravity compensation control torque feasibility value when said relative angular velocity between said first and second segments of said first joint is not substantially zero, including the steps of;

determining a mechanical energy feasibility value of said gravity compensation control torque,

determining a metabolic energy feasibility value of said gravity compensation control torque, and

calculating said gravity compensation control torque feasibility value based upon said mechanical energy feasibility value and said metabolic energy feasibility value.

2. The method of claim 1, wherein said mechanical energy feasibility value represents a relationship between a value of an assisted muscle torque and a value of an unassisted muscle torque.

3. The method of claim 1, wherein said metabolic energy feasibility value represents a relationship between a value of a metabolic cost of assisted control and a value of a metabolic cost of unassisted control.

4. The method of claim 1, further comprising the step of:

determining a stability feasibility factor for said gravity compensation control torque.

5. The method of claim 4, wherein said step of calculating said gravity compensation feasibility value is based upon said mechanical energy feasibility value, said metabolic energy feasibility value and said stability feasibility factor.

6. The method of claim 5, further comprising the step of applying said gravity compensation feasibility factor when said gravity compensation feasibility factor value exceeds a first threshold.

7. The method of claim 1, further comprising the step of applying said gravity compensation feasibility factor when said gravity compensation feasibility factor value exceeds a first threshold.

8. A method for obtaining an assist torque to be applied to a human joint, in a human assist system for applying an assist torque to the human joint, comprising the steps of:

determining a gravity compensation control torque value for a first joint;

identifying said gravity compensation control torque as being feasible if the relative angular velocity between first and second segments of the said first joint is substantially zero; and

identifying a gravity compensation control torque feasibility value when the relative angular velocity between said first and second segments of the said first joint is not substantially zero, including the steps of;

determining a mechanical energy feasibility value of said gravity compensation control torque,

determining a stability feasibility factor for said gravity compensation control torque, and

calculating said gravity compensation control torque feasibility value based upon said mechanical energy feasibility value and said stability feasibility factor.

9. The method of claim 8, wherein said mechanical energy feasibility value represents a relationship between a value of an assisted muscle torque and a value of an unassisted muscle torque.

10. A method for obtaining an assist torque to be applied to a human joint, in a human assist system for applying an assist torque to the human joint, comprising the steps of:

determining a gravity compensation control torque value for a first joint;

identifying said gravity compensation control torque as being feasible if the relative angular velocity between first and second segments of of the said first joint is substantially zero; and

identifying a gravity compensation control torque feasibility value when said angular velocity between said first and second segments of the said first joint is not substantially zero, including the steps of;

determining a metabolic energy feasibility value of said gravity compensation control torque,

determining a stability feasibility factor for said gravity compensation control torque, and

calculating said gravity compensation control torque feasibility value based upon said metabolic energy feasibility value and said stability feasibility factor.

11. A system for obtaining an assist torque to be applied to a human joint, in a human assist system for applying an assist torque to the human joint, comprising:

means for determining a gravity compensation control torque value for a first joint;

first identifying means for identifying said gravity compensation control torque as being feasible if the relative angular velocity between first and second segments of said first joint is substantially zero; and

second identifying means for identifying a gravity compensation control torque feasibility value when the said angular velocity between said first and second segments of the said first joint is not substantially zero, including;

mechanical feasibility means for determining a mechanical energy feasibility value of said gravity compensation control torque,

metabolic feasibility means for determining a metabolic energy feasibility value of said gravity compensation control torque, and

first calculating means for calculating said gravity compensation control torque feasibility value based upon said mechanical energy feasibility value and said metabolic energy feasibility value.

12. The system of claim 11, wherein said mechanical energy feasibility value represents a relationship between a value of an assisted muscle torque and a value of an unassisted muscle torque.

13. The system of claim 11, wherein said metabolic energy feasibility value represents a relationship between a value of a metabolic cost of assisted control and a value of a metabolic cost of unassisted control.

14. The system of claim 11, further comprising:

stability feasibility means for determining a stability feasibility factor for said gravity compensation control torque.

15. The system of claim 14, wherein said first compensation means calculates said gravity compensation feasibility value based upon said mechanical energy feasibility value, said metabolic energy feasibility value and said stability feasibility factor.

16. The system of claim 15, further comprising application means for applying said gravity compensation feasibility factor when said gravity compensation feasibility factor value exceeds a first threshold.

17. The system of claim 11, further comprising application means for applying said gravity compensation feasibility factor when said gravity compensation feasibility factor value exceeds a first threshold.

18. A system for obtaining an assist torque to be applied to a human joint, in a human assist system for applying an assist torque to the human joint, comprising:

means for determining a gravity compensation control torque value for a first joint;

first identifying means for identifying said gravity compensation control torque as being feasible if the angular velocity of between first and second segments of the said first joint is substantially zero; and

second identifying means for identifying a gravity compensation control torque feasibility value when said angular velocity between first and second segments of said first joint is not substantially zero, including;

mechanical feasibility means for determining a mechanical energy feasibility value of said gravity compensation control torque,

stability feasibility means for determining a stability feasibility factor for said gravity compensation control torque, and

first calculating means for calculating said gravity compensation control torque feasibility value based upon said mechanical energy feasibility value and said stability feasibility factor.

19. The system of claim 18, wherein said mechanical energy feasibility value represents a relationship between a value of an assisted muscle torque and a value of an unassisted muscle torque.

20. A system for obtaining an assist torque to be applied to a human joint, in a human assist system for applying an assist torque to the human joint, comprising:

means for determining a gravity compensation control torque value for a first joint;

first identifying means for identifying said gravity compensation control torque as being feasible if the said relative angular velocity between the first and second segments connecting the said first joint is substantially zero; and

second identifying means for identifying a gravity compensation control torque feasibility value when the said relative angular velocity between said first and second segments connecting the said first joint is not substantially zero, including;

metabolic feasibility means for determining a metabolic energy feasibility value of said gravity compensation control torque,

stability feasibility means for determining a stability feasibility factor for said gravity compensation control torque, and

first calculating means for calculating said gravity compensation control torque feasibility value based upon said metabolic energy feasibility value and said stability feasibility factor.