QB Robotics qbmove Advanced Kit, User Manual

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28 aprile 2021
6.5.2.6 Waypoint control
This control mode is a bit more structured and useful than the previous: it allows to set a fixed
trajectory of any number of position waypoints (with timing constraints) and set the robot to
cycle infinitely on it (because of the loop it is recommended to set the first and last waypoint in
a similar configuration to avoid unwanted sudden changes).
To start this mode just add
use_waypoints:=true
to the general
roslaunch
command (be sure that the opposite
use_controller_gui
is not used). You won't see
any control interface in this case but the qbmove should start moving according to the given
trajectory, parsed from a yaml file located at
<robot_package>_control/config/<robot_name>_waypoints.yaml
where robot_name and robot_package are two additional launch file arguments.
Customization
You can modify the waypoint trajectory to replicate the behavior you want: either change the
<robot_package>_control/config/<robot_name>_waypoints.yaml or add
another custom application-specific file in the config directory. In the second case, you need
to set the argument robot_name properly when launching the command from the terminal.
The waypoint configuration is as follows:
# Waypoints describe the desired motion trajectory:
# - time [s]: can be either a single value or an interval for w
hich joint_positions hold
# - joint_positions:
# - shaft position [radians] and stiffness preset [0,1];
# - joint_velocities: optional, use it only if you want a nonze
ro values
# - shaft position [radians/s] and stiffness preset [0,1]/s;
# - joint_accelerations: optional, use it only if you want a no
nzero values
# - shaft position [radians/s^2] and stiffness preset [0,1]/
s^2;
#
# It is worth noting that, if specified, joint_positions, joint_
velocities and joint_accelerations must be of size two.
waypoints:
-
time: [1.0]
joint_positions:
<device_name>: [0.0, 0.0]
-
time: [2.75, 3.25]
joint_positions:
<device_name>: [1.57, 0.0]