Allen-Bradley 1756-HYD02 User Manual page 88

Chapter 3 Geometries with no orientation support
88
The Delta robot in this illustration is a three-degree of freedom robot with an
optional fourth degree of freedom used to rotate a part at the tool tip. In the Logix
Designer application, the first three-degrees of freedom are configured as three
joint axes (J1, J2, J3) in the robots coordinate system. The three joint axes are:
•
Directly programmed in joint space.
•
Automatically controlled by the embedded Kinematics software in the
Logix Designer application from instructions programmed in a virtual
Cartesian coordinate system.
This robot contains a fixed top plate and a moving bottom plate. The fixed top
plate is attached to the moving bottom plate by three link-arm assemblies. All
three of the link-arm assemblies have a single top link arm (L1) and a
parallelogram two-bar link assembly (L2).
As each axis (J1, J2, J3) is rotated, the TCP of the gripper moves correspondingly
in (X1, X2, X3) direction. The gripper remains vertical along the X3 axis while its
position is translated to (X1, X2, X3) space by the mechanical action of the
parallelograms in each of the forearm assemblies. The mechanical connections of
the parallelograms via spherical joints ensures that the top and bottom plates
remain parallel to each other.
Program the TCP to an (X1, X2, X3) coordinate, then the Logix Designer
application computes the commands necessary for each of the joints (J1, J2 ,J3) to
move the gripper linearly from the current (X1, X2, X3) position to the
programmed (X1, X2, X3) position, at the programmed vector dynamics.
When each top link (L1) moves downward, its corresponding joint axis (J1, J2, or
J3) is assumed to be rotating in the positive direction. The three joint axes of the
robot are configured as linear axes.
To rotate the gripper, configure a fourth axis as a linear or rotary, independent
axis.
See also
Establish the reference frame for a Delta Three-dimensional robot
89
Calibrate a Delta Three-dimensional robot
Configure Zero Angle Orientation for Delta Three-dimensional robot
page 90
Identify the Work Envelope for Delta Three-dimensional robot
Rockwell Automation Publication MOTION-UM002F-EN-P - February 2018
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