Manipulator system

• US 8,423,190 B1
• Filed: 05/24/2010
• Issued: 04/16/2013
• Est. Priority Date: 06/11/2009
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Yaskawa Denki
• Original Assignee: Kabushiki Kaisha Yaskawa Denki
• Inventors: Yasuda, Ken'ichi, Maeda, Takahiro
• Primary Examiner(s): To, Tuan C.
• Assistant Examiner(s): Kan, Yuri
• Application Number:
  US12/786,384
• Time in Patent Office: 1,058 Days
• Field of Search: 700/165, 700/248, 700/251, 700/254, 700/262, 335/03, 606/1, 378/209, 318/568.2, 702/152, 180/8.1
• US Class Current: 700/263
• CPC Class Codes: B25J 17/00 Joints
• CPC Class Codes: B25J 18/00 Arms
• CPC Class Codes: B25J 9/1674 characterised by safety, monitoring, diagnostic
• CPC Class Codes: G05B 15/00 Systems controlled by a computer G05B13/00, G05B19/00 take precedence; automatic controllers with particular characteristics G05B11/00
• CPC Class Codes: Y10S 901/02 Arm motion controller
• CPC Class Codes: Y10S 901/27 Arm part
• CPC Class Codes: Y10T 74/20329 Joint between elements

Abstract

From a desired wrist joint position and a desired elbow rotation angle, a temporary elbow joint position is calculated on the assumption that a distance between a shoulder joint and an elbow joint is fixed. The shoulder joint has a first axis, a second axis, and a third axis, and the elbow joint has a fourth axis. From the calculated temporary elbow joint position, temporary angles of the first and second axes or temporary angles of the first to fourth axes are determined. The temporary angles are corrected in accordance with at least one evaluation function calculated from the temporary angles.

Claims

1. A manipulator system comprising:

a shoulder joint having a first axis, a second axis, and a third axis;

a wrist joint having a fifth axis, a sixth axis, and a seventh axis;

an elbow joint having a fourth axis;

an upper-arm link connected to the shoulder joint and the elbow joint;

a lower-arm link connected to the elbow joint and the wrist joint;

a shoulder reference point defining an intersection of the first axis of the shoulder joint and a straight line orthogonal to the first and second axes of the shoulder joint;

a wrist reference point a point at which the three axes of the wrist joint intersect;

an elbow reference point defining a coordinate origin of the fourth axis of the elbow joint; and

a command generating unit configured to;

calculate a temporary elbow position from a desired wrist reference point position and a desired elbow rotation angle based on the assumption that a distance between the shoulder reference point and the elbow reference point is fixed;

calculate temporary angles of at least the first and second axes from the temporary elbow position;

calculate an evaluation value using an evaluation function from the temporary angles; and

correct the temporary angles so that the evaluation value reaches a predetermined level, wherein the evaluation value is calculated using the evaluation function from the corrected temporary angles, and wherein the temporary angles are repeatedly corrected until the evaluation value from latest temporary angles reaches the predetermined level,

wherein in a process of correcting the temporary angles, correction angles for the first to fourth axes are calculated using a Jacobian matrix representing a micro-displacement relation between each of the temporary angles of the first to fourth axes and the wrist reference point position and between each of the temporary an les of the first to fourth axes and the elbow rotation angle.

2. The manipulator system according to claim 1, wherein as the evaluation function for correcting the temporary angles, a difference between the desired wrist reference point position and a wrist reference point position calculated from the temporary angles, and a difference between the desired elbow rotation angle and an elbow rotation angle calculated from the temporary angles are used.

3. A manipulator system comprising:

a shoulder joint having a first axis, a second axis, and a third axis;

a wrist joint having a fifth axis, a sixth axis, and a seventh axis;

an elbow joint having a fourth axis;

an upper-arm link connected to the shoulder joint and the elbow joint;

a lower-arm link connected to the elbow joint and the wrist joint;

a shoulder reference point defining an intersection of the first axis of the shoulder joint and a straight line orthogonal to the first and second axes of the shoulder joint;

a wrist reference point a point at which the three axes of the wrist joint intersect;

an elbow reference point defining a coordinate origin of the fourth axis of the elbow joint; and

a command generating unit configured to;

calculate a temporary elbow position from a desired wrist reference point position and a desired elbow rotation angle based on the assumption that a distance between the shoulder reference point and the elbow reference point is fixed;

calculate temporary angles of at least the first and second axes from the temporary elbow position;

calculate an evaluation value using an evaluation function from the temporary angles; and

correct the temporary angles so that the evaluation value reaches a predetermined level, wherein the evaluation value is calculated using the evaluation function from the corrected temporary angles, and wherein the temporary angles are repeatedly corrected until the evaluation value from latest temporary angles reaches the predetermined level,

wherein a plane passing through three points, the shoulder reference point, the wrist reference point, and the elbow reference point, is defined as an elbow plane; and

a difference between a direction cosine of an elbow plane calculated from the temporary angles and a direction cosine of a desired elbow plane is used as the evaluation function for correcting the temporary angles.

4. A manipulator system comprising:

a shoulder joint having a first axis, a second axis, and a third axis;

a wrist joint having a fifth axis, a sixth axis, and a seventh axis;

an elbow joint having a fourth axis;

an upper-arm link connected to the shoulder joint and the elbow joint;

a lower-arm link connected to the elbow joint and the wrist joint;

a command generating unit configured to;

calculate temporary angles of at least the first and second axes;

calculate an evaluation value using an evaluation function from the temporary angles;

correct the temporary angles in accordance with the evaluation value, wherein the evaluation value is calculated using the evaluation function from the corrected temporary angles, and wherein the temporary angles are repeatedly corrected until the evaluation value from latest temporary angles reaches to a predetermined level; and

a controller configured to control the shoulder joint, the elbow joint, and the wrist joint using the latest temporary angles corrected by the temporary angle corrector to manipulate a work object,

wherein in a process of correcting the temporary angles, correction angles for the first to fourth axes are calculated using a Jacobian matrix representing a micro-displacement relation between each of the temporary angles of the first to fourth axes and a wrist reference point position defined as a point at which the three axes of the wrist joint intersect, and between each of the temporary angles of the first to fourth axes and an elbow rotation angle.

5. The manipulator system according to claim 4, wherein the first axis of the shoulder joint is offset from the second axis of the shoulder joint by a distance along a straight line orthogonal to the first and second axes of the shoulder joint.

6. A manipulator system comprising:

a shoulder joint having a first axis, a second axis, and a third axis;

a wrist joint having a fifth axis, a sixth axis, and a seventh axis;

an elbow joint having a fourth axis;

an upper-arm link connected to the shoulder joint and the elbow joint;

a lower-arm link connected to the elbow joint and the wrist joint;

a shoulder reference point defining an intersection of the first axis of the shoulder joint and a straight line orthogonal to the first and second axes of the shoulder joint;

a wrist reference point a point at which the three axes of the wrist joint intersect;

an elbow reference point defining a coordinate origin of the fourth axis of the elbow joint;

a command generating unit configured to;

calculate temporary angles of at least the first and second axes;

calculate an evaluation value using an evaluation function from the temporary angles;

correct the temporary angles in accordance with the evaluation value, wherein the evaluation value is calculated using the evaluation function from the corrected temporary angles, and wherein the temporary angles are repeatedly corrected until the evaluation value from latest temporary angles reaches to a predetermined level; and

a controller configured to control the shoulder joint, the elbow joint, and the wrist joint using the latest temporary angles corrected by the temporary angle corrector to manipulate a work object,

wherein a plane passing through three points, the shoulder reference point, the wrist reference point, and the elbow reference point, is defined as an elbow plane; and

a difference between a direction cosine of an elbow plane calculated from the temporary angles and a direction cosine of a desired elbow plane is used as the evaluation function for correcting the temporary angles.