This package includes the door opening skill as well as the scripts and monitors created for it. The goal of the door opening skill is to open a door with a smooth motion by reducing forces against the tool.
This package includes the following scripts, monitors and skills
- script_temp_frame_offset
- script_temp_frame_center_of_circle
- monitor_relative_angular_distance
- skill_door_opening
A monitor that looks at the rotation of a frame around the reference frame. Created to circumvent the problem with the monitor monitor_distance that only calculates the rotational change of the frame.
Monitor calculates the angle between the starting and current position of the observed frame around a static
reference_frame. Reduces the problem into a 2D problem by removing the in coordinates selected axis and
assuming every data point is in the same plane. Only the position, and not the rotation of the observed frame,
is relevant for the monitor. Triggers when the rotation around the in coordinates selected axis exceeds/passes
a certain threshold depending on the operator set. Every coordinate is handled individually. Triggers if true for
every coordinate.
reference_frame
A static frame around which the moving frame rotates
frame
Moving/Observed frame
coordinates
Observed axes. The axis of the reference_frame which the angle is calculated around.
distances
Distances threshold [rad] from 0 to 2 * Pi. The monitor triggers after passing or exceeding, depending on the
operator, this distance threshold. Aligned to the coordinates member.
operator:
The operator determines if the monitor triggers by comparing the distance threshold with the calculated distance.
The suggested value is "crossing_threshold" which makes the determination of the distances parameter simpler.
Also usable are "greater", "less", "absolute_greater", "absolute_less"
dead_zone: default: 0.001
Distance, in [rad], of zone around the starting position the monitor ignores. It is needed to ignore the potential
overflow of the distance parameters at the start of a rotation caused by a small imprecision of the robot.
A script that creates a temp frame that copies the position of a source frame and adds an offset to it
This script is a copy of the script_temp_frame that is implemented in pitasc by default with the addition of an
offset variable. The user sets a parent frame that sets up the reference coordinate system and a source frame
which determines the initial position of the temp frame. The offset is added to the source frame.
frame:
Name of the frame to be created
source:
Name of the frame from which the initial position is copied
parent:
Name of the parent frame of frame
offset: Default: 0,0,0,0,0,0
Offset of the new frame relative to the source frame
Creates a temporary frame and moves it to the center point of a frame that moves in a circular path.
The z-axis of the source frame plus offset is assumed to be perpendicular to the plane of rotation. Uses the x, y positional values of the observed frame relative to the source frame plus offset to approximate the x and y position of the temp frame. The z position is set to 0. Uses the Taubin Circle Fit Method for finding the center point. The frame's position will be updated as long as the script is active.
*Every parameter of script_temp_frame_offset
This script inherits from script_temp_frame_offset.
tool_frame
The name of the frame the data points are taken from.
The functionality of this skill can be separated into two parts, the initial rotation and the follow-up rotation.
At the beginning, the skill creates two new frames called ref_frame and calc_center at the position and
orientation of the source_frame plus the offset. The tool_frame starts rotating around the z-axis of the
ref_frame and starts calculating the position of the calc_center using the
script_temp_frame_center_of_circle script. After the tool_frame passes the calc_distance threshold, this
initial step gets aborted and the second step starts. Now the tool_frame no longer rotates around the ref_frame
but the calc_center frame. The position of the calc_center frame still continues to be updated by the
script_temp_frame_center_of_circle script. After the tool_frame passes the distance threshold, the skill is
completed and the rotation stops. Throughout this whole process, the forces on the corresponding axis of the
tool_frame are set to 0 so that the tool_frame moves according to the door rotation.
tool_frame:
Moving/Observed frame
parent_frame:
The name of the parent frame of the source_frame and the created calc_center frame
source_frame:
The name of the frame from which the initial position is copied
offset: default: 0, 0, 0, 0, 0, 0
Offset of the new frame relative to the source_frame frame
force_axes: default: x
List of axes
target_forces: default: 0
Forces and torques to be applied. Must be the same number of values as for force_axes.
compliance: default: 0.002
Force controller gain
corner_frequency: default: 5.0
Force controller corner frequency
velocities: default: 0, 0.1, 0, 0, 0, 0
The speed at which the tool frame moves.
Only change the second value of the CSV. Every other value has to be 0
distance: default: 1.31
The second distances threshold [rad] from 0 to 2 * Pi that is used to approximate the center position after the
initial step. The monitor triggers after passing this distance threshold. Aligned to the the z-axis of the
source_frame plus offset.
distance_calc: default: 0.26
The initial distances threshold [rad] from 0 to 2 * Pi is used to approximate the center position with the
first few positional values of the initial movement. The monitor triggers after passing, this distance threshold.
Aligned to the z-axis of the source_frame plus offset.
monitor_dead_zone: default: 0.001
Distance, in [rad], of zone around the starting position the monitor ignores. It is needed to ignore the potential
overflow of the distance parameters at the start of a rotation caused by a small imprecision of the robot.