Goniometer-based body-tracking device and method

• US 20030083596A1
• Filed: 08/05/2002
• Published: 05/01/2003
• Est. Priority Date: 04/21/1997
• Status: Active Grant

• Current Assignee: Immersion Corporation
• Original Assignee: Immersion Corporation
• Inventors: McNamara, Conor, Kramer, James F., Ananny, John M., Boronkay, Allen R., Korff, Paul L., Bentley, Loren F.
• Granted Patent: US 7,070,571 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 2562/0261 Strain gauges
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/1071 measuring angles, e.g. using goniometers A61B5/1123 takes precedence
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1122 of movement trajectories
• CPC Class Codes: A61B 5/1124 Determining motor skills
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/6804 Garments; Clothes
• CPC Class Codes: A61B 5/6806 Gloves
• CPC Class Codes: A61B 5/6807 Footwear
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00

Abstract

A sensing system is provided for measuring various joints of a human body for applications for performance animation, biomechanical studies and general motion capture. One sensing device of the system is a linkage-based sensing structure comprising rigid links interconnected by revolute joints, where each joint angle is measured by a resistive bend sensor or other convenient goniometer. Such a linkage-based sensing structure is typically used for measuring joints of the body, such as the shoulders, hips, neck, back and forearm, which have more than a single rotary degree of freedom of movement. In one embodiment of the linkage-based sensing structure, a single long resistive bend sensor measures the angle of more that one revolute joint. The terminal ends of the linkage-based sensing structure are secured to the body such that movement of the joint is measured by the device. A second sensing device of the sensing system comprises a flat, flexible resistive bend sensor guided by a channel on an elastic garment. Such a flat sensing device is typically used to measure various other joints of the body which have primarily one degree of freedom of movement, such as the elbows, knees and ankles. Combining the two sensing devices as described, the sensing system has low sensor bulk at body extremities, yet accurately measures the multi-degree-of-freedom joints nearer the torso. Such a system can operate totally untethered, in real time, and without concern for electromagnetic interference or sensor occlusion.

Claims

1. An apparatus for measuring the relative spatial placement of two terminal links, said apparatus connected by links and revolute joints and comprising:

at least one of the following sensing devices;

a first sensing device comprising a long resistive bend sensor extending over multiple joints with parallel axes from terminal link to terminal link; and

a second sensing device comprising multiple short resistive bend sensors and multiple links and revolute joints and terminating in terminal links, with each sensor measuring one revolute joint angle;

means for mounting said sensing device on said body parts; and

means for receiving electrical signals from said sensing device;

wherein said first sensing device provides a signal for the entire angle between said terminal links and said second sensing device provides a signal such that the relative position and orientation of said terminal links can be determined using forward kinematics.

2. An apparatus for measuring angles of portions of a human body, said portions comprising at least one of the shoulder and the hip, said apparatus comprising:

at least one of the following sensing devices;

a first sensing device comprising a long resistive bend sensor extending over multiple joints with parallel axes from terminal link to terminal link; and

a second sensing device comprising multiple short resistive bend sensors and multiple links and revolute joints and terminating in terminal links, with each sensor measuring one revolute joint angle;

for the shoulder, means for securing said sensing device to said human body to measure the angle of the humerus in relation to the torso, whereby one terminal link moves with said humerus and the other terminal link moves with said torso;

for the hip, means for securing said sensing device to said human body to measure the angle of the femur in relation to the torso, whereby one terminal link moves with said femur and the other terminal link moves with said torso;

a data processor for receiving electrical signals from said sensing devices and determining angles from said signals.

3. An apparatus according to claim 2, comprising sensing devices for measuring both said shoulder and said hip.

4. An apparatus according to claim 2, further comprising:

at least one resistive bend sensor for measuring an elbow, wrist, knee or ankle body part;

means for mounting said resistive bend sensor in angle-measuring relation to said elbow, wrist, knee or ankle body part.

5. An apparatus for measuring angles of portions of a human body, said portions comprising at least one of the shoulder and the hip, said apparatus comprising:

at least one prismatic sensing device for measuring said angle in relation to at least one of said shoulder and hip;

optionally at least one of the following revolute sensing devices;

a first sensing device comprising a long resistive bend sensor extending over multiple joints with parallel axes from terminal link to terminal link; and

a second sensing device comprising multiple short resistive bend sensors and multiple links and revolute joints and terminating in terminal links, with each sensor measuring one revolute joint angle;

at least one resistive bend sensor for measuring an elbow, wrist, knee or ankle body part;

means for mounting said resistive bend sensor in angle-measuring relation to said elbow, wrist, knee or ankle body part;

for the shoulder, means for securing said sensing device to said human body to measure the angle of the humerus in relation to the torso, whereby one terminal link moves with said humerus and the other terminal link moves with said torso;

for the hip, means for securing said sensing device to said human body to measure the angle of the femur in relation to the torso, whereby one terminal link moves with said femur and the other terminal link moves with said torso;

a data processor for receiving electrical signals from said sensing devices and sensors and determining angles from said signals.

6. An apparatus for measuring the orientation of two body parts having up to three degrees of freedom of orientation and position relative to each other, said device comprising:

at least two revolute sensing devices connected together;

wherein said sensing devices are selected from;

a first sensing device comprising a long resistive bend sensor extending over multiple joints with parallel axes; and

a second sensing device comprising multiple short resistive bend sensors and multiple links and revolute joints, with each sensor measuring one revolute joint angle;

where when said second sensing device is absent, at least two of said first sensing devices articulate in different planes;

first and second terminal links at the ends of said apparatus;

means for securing said terminal links to said body parts;

a data processor for receiving electrical signals from said sensing devices and determining orientation from said signals, and when solely said second sensing device is used, further determining position from said signals.

7. An apparatus according to claim 6, wherein said second sensing device is absent, said apparatus further comprising at least one revolute joint measured by a short resistive bend sensor.

8. An apparatus according to claim 6, wherein said body parts comprise the thoracic region of the spine and humerus.

9. An apparatus according to claim 6, wherein said body parts comprises the pelvis and the femur.

10. An apparatus comprising a plurality of links and at least one revolute joint, said apparatus comprising:

assembled units, where each unit comprises a body with first and second components secured together, said units comprising linking means for linking a series of units and a passageway for receiving a sensor extending through said assembled units,

said units formed by joining face-to-face said first and second components, each of said components comprising a post at one end extending outward, where the two posts are spaced apart when said units are joined to define a portion of said passageway, an orofice at the other end for receiving a post of an adjoining unit, and one half of said passageway;

a sensor extending through said passageway; and

means for electrical connection to said sensor.

11. A method for measuring angles of portions of a human body wherein at least one of said portions comprising at least one of the shoulder and the hip, comprising:

providing a sensing device selected from the group of sensing devices onsisting of;

(i) a first sensing device including a long resistive bend sensor extending over multiple joints with parallel axes from terminal link to terminal link;

(ii) a second sensing device including multiple short resistive bend sensors and multiple links and revolute joints and terminating in terminal links, with each sensor measuring one revolute joint angle;

for the shoulder, securing said sensing device to said human body proximate the shoulder; and

measuring the angle of the humerus in relation to the torso such that one terminal link moves with said humerus and the other terminal link moves with said torso;

for the hip, securing said sensing device to said human body; and

measuring the angle of the femur in relation to the torso, such that one terminal link moves with said femur and the other terminal link moves with said torso; and

receiving electrical signals from said sensing devices and processing said signals in a computer processor to determine angles from said signals.