How-to: Control ARI’s eyes#

Both the expression and the position of ARI’s eyes can be controlled via ROS.

Note

Currently, the eyes can only be controlled through a ROS interface. In future releases of the SDK, alternative no-code solutions will be offered.

Expressions#

../_images/cycle_expressions.gif

The expression of the eyes can be changed via the /eyes/expression topic.

You can either use one of the pre-defined expressions (like happy, confused… see list below), or by setting a custom values for valence and arousal, following the circumplex model of emotions.

Code samples#

The following short snippet of Python code loops over several expressions, as show in the animation above:

Cycle through some of ARI’s expressions#
 1import rospy
 2from hri_msgs.msg import Expression
 3
 4if __name__ == "__main__":
 5
 6  rospy.init_node("publisher")
 7  pub = rospy.Publisher("/eyes/expression", Expression, queue_size=10)
 8
 9  msg = Expression()
10  expressions = ["happy", "confused", "angry", "sad", "amazed", "rejected"]
11
12  rate = rospy.Rate(1) # 1Hz
13  idx = 0
14
15  while not rospy.is_shutdown():
16     msg.expression = expressions[idx % len(expressions)]
17     pub.publish(msg)
18
19     idx += 1
20     rate.sleep()

This second example changes the expression continuously, by increasing/decreasing the valence and arousal:

Change expression based on valence and arousal#
 1import rospy
 2from hri_msgs.msg import Expression
 3
 4if __name__ == "__main__":
 5
 6  rospy.init_node("publisher")
 7  pub = rospy.Publisher("/eyes/expression", Expression, queue_size=10)
 8
 9  msg = Expression()
10
11  rate = rospy.Rate(5)
12
13  valence = 0.
14  arousal = 0.
15  valence_delta = 0.05
16  arousal_delta = 0.0
17
18  while not rospy.is_shutdown():
19     msg.valence = valence
20     msg.arousal = arousal
21
22     valence += valence_delta
23     arousal += arousal_delta
24
25     if valence > 1:
26         valence = 1
27         valence_delta = 0.
28         arousal_delta = 0.05
29     if arousal > 1:
30         arousal = 1
31         valence_delta = -0.05
32         arousal_delta = 0.0
33     if valence < -1:
34         valence = -1
35         valence_delta = 0.0
36         arousal_delta = -0.05
37     if arousal < -1:
38         arousal = -1
39         valence_delta = 0.05
40         arousal_delta = 0.0
41
42     print("Valence: %.1f; arousal: %.1f" % (valence, arousal))
43     pub.publish(msg)
44
45     rate.sleep()

List of expressions#

The hri_msgs/Expression ROS message lists all pre-defined expression. The table below shows how these expressions are rendered on the robot.

Expression name

Appearance

Expression name

Appearance

neutral

 ../_images/eyes_neutral.png

angry

 ../_images/eyes_angry.png

sad

 ../_images/eyes_sad.png

happy

 ../_images/eyes_happy.png

surprised

 ../_images/eyes_surprised.png

disgusted

 ../_images/eyes_disgusted.png

scared

 ../_images/eyes_scared.png

pleading

 ../_images/eyes_pleading.png

vulnerable

 ../_images/eyes_vulnerable.png

despaired

 ../_images/eyes_despaired.png

guilty

 ../_images/eyes_guilty.png

disappointed

 ../_images/eyes_disappointed.png

embarrassed

 ../_images/eyes_embarrassed.png

horrified

 ../_images/eyes_horrified.png

skeptical

 ../_images/eyes_skeptical.png

annoyed

 ../_images/eyes_annoyed.png

furious

 ../_images/eyes_furious.png

suspicious

 ../_images/eyes_suspicious.png

rejected

 ../_images/eyes_rejected.png

bored

 ../_images/eyes_bored.png

tired

 ../_images/eyes_tired.png

asleep

 ../_images/eyes_asleep.png

confused

 ../_images/eyes_confused.png

amazed

 ../_images/eyes_amazed.png

excited

 ../_images/eyes_excited.png

Gaze direction#

Basic control#

The position of the eyes can controlled by publishing a target position (3D point) to the /look_at topic:

Set the gaze direction#
 1import rospy
 2from geometry_msgs.msg import PointStamped
 3
 4
 5rospy.init_node("publisher")
 6
 7pub = rospy.Publisher("/look_at", PointStamped, queue_size=10)
 8
 9target = PointStamped()
10
11# look at a point located 1.5m above, and 2m left of the world origin
12target.header.frame_id = "map"
13target.point.x = 0.
14target.point.y = -2.
15target.point.z = 1.5
16
17pub.publish(target)

Controlling the gazing style#

The default gazing behaviour combines the eye (pupils) motion with the head motion to generate a natural and smooth gazing transition.

In some situation, you might want more control on the gazing style (eg, quick glance, quick head motion due to surprise, etc).

The /look_at_with_style let you configure the style of gaze, via the hri_action_msgs/LookAtWithStyle ROS message.

Note

In pal-sdk-23.1, only basic gazing style are available (namely, eyes only and head only). Additional gazing style will be added in future SDK releases.

See also#