Determining positions
First Claim
1. An apparatus for determining the position of the end of a robot arm that is movable within a frame of reference, the robot arm having several degrees of freedom, the robot arm being mounted on a base and including a wrist mechanism, the wrist mechanism including a rotational support element, the apparatus comprising a multiplicity of first targets fixed relative to the wrist mechanism of the robot arm, and a multiplicity of base elements at fixed positions relative to the frame of reference, the apparatus also comprising an optical measurement system including optical means movable with the robot arm, wherein the base elements are around the base of the robot, and the first targets are arranged as arm targets around the rotational support element of the wrist mechanism, and the movable optical means is mounted on or adjacent to the robot arm, and the optical measurement system comprising means to enable the positions of at least some of the base elements relative to the movable optical means and the positions of at least some of the arm targets relative to the movable optical means to be determined.
2 Assignments
0 Petitions
Accused Products
Abstract
The position of a movable element such as the end of a robot arm (10) which has several degrees of freedom, being mounted on a base (11) and including a wrist mechanism, is determined by installing a multiplicity of base targets (32, 74) around the base of the robot, and a multiplicity of arm targets (42, 74) around the base (14) of the wrist mechanism (15), and an optical means (90) that moves with the movable element to determine the positions of at least some of the base targets and of at least some of the arm targets. The optical means may be a laser tracker or a camera system (90), and it may be mounted on the part (13) of the robot arm to which the base (14) of the wrist mechanism (15) is connected. This enables existing robots (10) to achieve absolute positional accuracy relative to a fixed external frame of reference.
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Citations
13 Claims
- 1. An apparatus for determining the position of the end of a robot arm that is movable within a frame of reference, the robot arm having several degrees of freedom, the robot arm being mounted on a base and including a wrist mechanism, the wrist mechanism including a rotational support element, the apparatus comprising a multiplicity of first targets fixed relative to the wrist mechanism of the robot arm, and a multiplicity of base elements at fixed positions relative to the frame of reference, the apparatus also comprising an optical measurement system including optical means movable with the robot arm, wherein the base elements are around the base of the robot, and the first targets are arranged as arm targets around the rotational support element of the wrist mechanism, and the movable optical means is mounted on or adjacent to the robot arm, and the optical measurement system comprising means to enable the positions of at least some of the base elements relative to the movable optical means and the positions of at least some of the arm targets relative to the movable optical means to be determined.
Specification