Grid Dialog
Description
When creating a new grid, the properties of the location are set in the Define New Grid Dialog. To define a new grid, either left-click on the Locator menu (top right) or right-click inside the table and select Define New Grid.
The relevant fields in the Location Dialog are:
Name
Select Tool
Task Space (X, Y, Z) Origin
IK Solution
Axis Count
Axis Pitch
Grid Angle
Index Order
Name
The name of the grid. Must be unique and a legal Python identifier.
The names of locations in a grid are shown as the name of the grid with their index appended in square brackets to show their relationship to the parent structure. Indexing starts at 0 and increases in value. For example, the first location in a grid called “my grid” will be displayed as my_grid[0], the second as my_grid[1], the third as my_grid[2], and so on.
Select Tool
Select Tool allows users to define which tool is performing an action when the robot is in a given pose. Select Tool defines the kinematic relationship between the joint space and Task Space coordinates.
By changing the tool selection from Gripper to Pipette Tip, for example, the same (x, y, z) in Task Space will produce two different poses in Joint Space to accomadate how the robot moves when different tools are equipped on the gripper.
Task Space (X, Y, Z) Origin
Defines the origin point for each axis. Using the X Origin, Y Origin, and Z Origin fields, the user may define the first element in each grid (my_grid[0]). By convention, the first element is the minimum value of all elements in the x-, y-, and z-axes. The positions of subsequent grid elements are generated by adding the multiples of the Axis Pitch to the corresponding axis origin coordinate.
Theta sets the orientation of the gripper axis with respect to the global +X axis.
IK Solution
The IK Solution setting controls whether the position currently displayed in the Task Space fields is achieved using a shoulder-center or shoulder-out pose of the N9 axes. See IK Solutions.
Axis Count
The integer number of elements along each axis of the grid. The x, y, and z directions refer to the axes of the global coordinate system. To create a grid rotated in the global XY plane, first enter the count and pitch parameters as if the grid was aligned in its default orientation, then use the Grid Angle field to rotate the grid by the desired angle. Grid elements are indexed in row-major order, starting from the origin element and counting up the z-axis, then along the y-axis, and finally along the x-axis. Notably, a grid of locations in the XY plane will share a single Z index. The minimum value in each axis field is one.
Axis Pitch
The spacing between grid elements along each axis, given in mm. Positive pitch values build the grid in the positive x, y, z directions of the global coordinate system. That is, when the simulator is oriented such that the robot is facing the user, the grid is built from the Origin to the left, toward the user, and up (positive x, y, and z respectively). Conversely, a negative pitch value will build the grid in the negative x, y, or z direction.
Grid Angle
The rotational angle of the grid around the local z-axis, given units of degrees. The rotation is calculated after the grid is created and aligned with the global x-axis.
Order Index
The order in which grid elements are indexed, following similar logic to row- and column-major ordering.
Default ordering is Z-Y-X. Users can change index order using the drop-down menu. In a theoretical 3x3x3 grid with a Z-Y-X order and positive pitch on all axes, grid elements are indexed as shown in the tables below.
NOTE: The axis values used in the above example are in arbitrary units of distance for ease of understanding. They do not reflect realistic Task Space coordinates for these elements.
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