Abstract—Biology can provide biomimetic components and
new control principles for robotics. Developing a robot system
equipped with bionic eyes is a difficult but exciting task.
Researchers have been studying the control mechanisms of
bionic eyes for many years and considerable models are
available. In this paper, control model and its implementation
on robots for bionic eyes are reviewed, which covers saccade,
smooth pursuit, vergence, vestibule-ocular reflex (VOR),
optokinetic reflex (OKR) and eye-head coordination. What is
more, some problems and possible solutions in the field of bionic
eyes are discussed and analyzed. This review paper can be used
as a guide for researchers to identify potential research
problems and solutions of the bionic eyes’ motion control.
I. INTRODUCTION
Eyes are the most important sensors for human beings
during the process of information acquisition. More than 80
percent of information is acquired by eyes. The human visual
system is highly developed and perfect after millions of years
of evolution. Visual system can lock the object at the center of
the retina (foveal area) even when the position of head or
object changes drastically. This is of great significance for
robots who always work in the bumpy and unstructured
environment. Studying bionic eyes which can act like human
beings is a difficult but exciting task. A robot system equipped
with bionic eyes has a better performance in terms of
perception and control.
Main motion forms of bionic eyes include saccade, smooth
pursuit, vergence, vestibule-ocular reflex (VOR), optokinetic
reflex (OKR) and eye-head coordination. Saccade is used to
move eyes voluntarily from one point to another by rapid
jumping, while smooth pursuit can be applied to track moving
targets. VOR acts to stabilize retinal images by generating a
compensatory eye motion during head turns. OKR can
stabilize retinal images for gazing at rapid moving objects by
nystagmus. OKR is driven by retinal slip while VOR is driven
by head velocity signal. Commonly, two or more forms of
motion work simultaneously. Besides, the binocular
coordination and eye-head coordination are of high
importance to realize object tracking and gaze control.
The control mechanisms of bionic eyes have been studied
for many years. Besides, some robot systems equipped with
bionic eyes have been designed to implement these control
models. Some typical systems of them are listed as following:
The iCub robot [1] has 3 DOFs on the neck and 3 DOFs for the
eyes. The KOBIAN robot [2] has 3 DOFs on the eyes, and 4
DOFs on the neck. The ARMAR robot [3] is designed to study
*Resrach supported in part by the National Natural Science Foundation of
China under Grant No. 61403378 and in part by the National High
Technology Research and Development Program of China under Grant No.
2015AA042307.
The authors are with Institute of Automation, Chinese Academy of
Sciences, Beijing 100190, China (email: { zhuzheng2014, wangqingbin2012,
wei.zou, feng.zhang }@ia.ac.cn).
gaze control. The Romeo [4] is a humanoid robot which
employs 4 DOFs in the eyes. There are also some robot head
systems such as the BARTHOC head[5] and the Flobi head[6]
et al. Implementations of bionic eyes‟ motion control
mechanisms on these robot systems have validated their
effectiveness for improving perception performance. However,
restricted to the development of neuroscience, there are
difficulties when imitating the performance of human eyes.
The purpose of studying bionics is to imitate eye
movements of primates to get a better performance in many
aspects, such as gaze shifts and image stabilization. Most
previous overviews about bionic eyes focused on the study of
neurophysiology and designed control models to imitate these
behaviors, but implementations of these control models on
robot systems are always ignored. So, besides the current
state-of-the-art of bionic eyes‟ control mechanisms, their
implementations on robot system are also discussed and
analyzed in this paper. This review paper can be used as a
guide for researchers to identify potential benefits and
limitations of the bionic eyes‟ study.
The paper is organized as follows: In Section II, research
status of different forms of bionic eyes‟ motion is summarized,
including saccade, smooth pursuit, VOR, OKR and eye-head
coordination. Various models and their features are
highlighted. What is more, implementations of control models
on robots are presented. In Section III, some problems and
possible solutions in the field of bionic eyes are discussed and
analyzed. Finally, conclusions are drawn in Section IV.
II. OVERVIEW OF MOTION CONTROL ON BIONIC EYES
Biology can provide biomimetic components and new
control principles for robotics. The motion forms of primate
eyes include saccade, smooth pursuit, vergence, VOR, OKR
and eye-head coordination. Studying on these motion forms
can help researchers to improve the performance of the robots‟
visual systems, including image stabilization, object tracking,
navigation, and so on. Thanks to the efforts of many
researchers, considerable control models for bionic eyes and
their implementations are available.
A. Models of Saccade
Saccade is used to move eyes voluntarily from one point to
another by rapid jumping. It is of great significance for robots
to change their fixation point quickly. In the control models,
saccade control system should act as a position servo
controller to change and keep the target at the center of the
retina with minimum time consuming.
Young and Stark [7] proposed the sampled data model for
saccade in 1963, which is shown in Fig.1. The circuit contains
the dead zone and the INHBT (a device to inhibit the timing
circuit), when the error exceeds a certain threshold, the pulse
generator is triggered which causes a sample to be taken, at the
same time, the INHBT element blocks dead zone for 0.2
Overview of Motion Control on Bionic Eyes*
Zheng Zhu, Qingbin Wang, Wei Zou, and Feng Zhang
Proceedings of the 2015
IEEE Conference on Robotics and Biomimetics
Zhuhai, China, December 6-9, 2015
978-1-4673-9675-2/15/$31.00 © 2015 IEEE
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