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| Learn More | Robot Workspace |
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| What is Workspace? |
| Dexterous and Accessible workspace? |
| Developing the workspace |
| Examples |
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| What is Workspace? |
In order to study the workspace of a robot, the structure of the robot can be considered as consisting of the arm and the hand. The arm is the large regional structure for global positioning of the hand, which is the small orientation structure for orientating the tool.
The primary workspace of such a robot with a large regional structure and a small orientation structure is determined by the arm. The hand generates the secondary workspace of a robot.
In performing tasks, a manipulator has to reach a number of workpieces or fixtures. Workspace is a volume of space which the end-effector of the manipulator can reach. Workspace is also called work volume or work envelope.
The size and shape of the workspace depends on the coordinate geometry of the robot arm, and also on the number of degrees of freedom. Some workspaces are quite flat, confined almost entirely to one horizontal plane. Others are cylindrical; still others are spherical. Some workspaces have very complicated shapes.
When choosing a robot arm for a certain industrial purpose, it is important that the workspace be large enough to encompass all the points that the robot arm will need to reach. But it's wasteful to use a robot arm with a workspace much bigger than necessary.
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| Dexterous and Accessible workspace? |
The workspace of a robot is an important criterion in evaluating manipulator geometries. Manipulator workspace may be described in terms of the dexterous workspace and the accessible workspace. Dexterous workspace is the volume of space which the robot can reach with all orientations. That is, at each point in the dexterous workspace, the end-effector can be arbitrarily oriented.
The accessible workspace is the volume of space which the robot can reach in at least one orientation. In the dexterous workspace the robot has complete manipulative capability. However, in the accessible workspace, the manipulator's operational capacity is limited because the terminal device can only be placed in a restricted range of orientations.
In other words, the dexterous workspace is a subset of the accessible workspace.
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| Developing the workspace |
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Left figure shows the work area of two- and three-link robots. These plots can be obtained on a microcomputer programmed so that the numeric keypad could be used to move each link.
The procedure for obtaining these areas is to move each link through its angular range of motion in a manner similar to the physical motion of the robot arm.
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| Examples |
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This drawing shows a simple example for a robot arm using cylindrical coordinate geometry. The set of points that the end effector can reach lies within two concentric cylinders, labeled "inner limit" and "outer limit". The workspace for this robot arm is shaped something like part of a brand new roll of duct tape.
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This is a rendering of a Puma 560 Reachable Workspace. The interior is hollow, representing workspace singularities caused by joint limits.
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| VRML Workspace |
| View same workspace as above, except in VRML 3D format. You can fly into the interior void. |
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