IEEE Robotics & Automation Magazine - March 2015 - 87

Dynamical SyStemS laboratory of new york UniverSity Polytechnic
School of engineering

and zoos have started incorporating touchscreen tablets and
smart devices into their displays [13]-[15]. These experiences
allow free-choice learners to interact through their smart
devices with images and animations in information kiosks or
projected displays [13]-[15].
While the integration of interactive smart devices with the
state-of-the-art robotics in informal science education is still
untapped, our group has demonstrated the feasibility of
increasing the engagement of young participants in a formal
robotics-based program through the smart devices [16]. The
program takes place at the New York Aquarium, where small
classes of young students are first given a tour of the aquarium
to learn about fish swimming and then tasked with designing
the caudal fin of a robotic fish based on what they have
observed [17]. Students are ultimately given the chance to drive
their robotic fish with a remote control in races with their colleagues, which serves as a validation of the students' bioinspired
design. In a series of events, participants indicated an increased
interest in science, technology, engineering, and mathematics
careers after the program [17], and, similar to the utilization of
touchscreens in the classroom [12], they showed a preference
for touchscreen devices over traditional controllers for remotely
controlling their robotic fish [16]. In this study, students also
found the interface of touchscreen devices to have a higher
usability as compared with a traditional remote.
Here, we leverage these findings toward the design and
development of a biomimetic robotic fish remotely controlled by an iDevice app for use in informal science education. We specifically envision the deployment of this platform in informal science venues in which free-choice
learners can interact with the robotic fish in a series of activities through their smart device. The robotic fish builds on
the work of [5] and [18] and incorporates a three-degree-offreedom tail, a pitch control system, and a buoyancy control
system to enable 3-D underwater servomotors that are individually controlled to simulate fish undulation. The novelties
in the robotic fish design include the implementation of a
combined pitch and buoyancy control system for 3-D locomotion, the independence between the robotic fish shape
and its waterproofed electronics, and the inclusion of biomimetic swimming patterns.
In addition to such robotic advancements, we introduce a
spectrum of user-friendly touchscreen applications that are
created to engage free-choice learners in control of the robotic
fish while delivering salient educational content on robotics
and biology. An iDevice, specifically the Apple iPad mini, is
selected as the appropriate hardware for this app due to its
widespread usage as well as its portability, wireless networking
capacity, and high-resolution graphics. The general public's
familiarity with and interest in these devices are expected to
contribute to more natural interactions with our exhibit platform. The novel app affords three modes of control, which
vary in the degree of autonomy of the robotic fish. Beyond the
remote control of the robotic fish [16], we propose two additional modes of control in which the robotic fish is either prescribed a route to follow by the user through real-time video

(a)

10 cm
(b)
Figure 1. The front and side views of the (a) computer-aided design
(CAD) and (b) physical prototype of the robotic fish.

feedback, similar to [23], or is tasked to autonomously navigate the environment through infrared (IR) sensors. To demonstrate the feasibility of the platform, we perform a usability
study on elementary school students.
Hardware Description
The robotic fish developed in this article is shown in Figure 1.
The mechanical design consists of a motorized tail, an electronics housing, a pitch control system, and a buoyancy control system. This design is selected for its implementation
simplicity, ability for underwater swimming in 3-D, and
decoupling of the hardware from the aesthetics. Tail beating
allows for swimming in two dimensions (2-D), while the
pitch and buoyancy control system, located in the head of the
fish along with the electronics housing, are utilized for diving.
The cover of the robotic fish is designed in SolidWorks, taking inspiration from a scup fish, Stenotomus chrysops [24],
and built out of solid-packing acrylonitrile butadiene styrene
(ABS) material printed from a Stratasys rapid prototyping
machine. Finally, the cover is painted using nontoxic colors
inspired by the natural color pattern found in scup fish [24].
The robotic fish measures 46 cm in length, 19 cm in height,
and 10 cm in width and weighs 1,170 g. The servomotors and
electronics are individually waterproofed to improve the
durability of the robot and facilitate variations of its aesthetics.
Electronics Housing
The electronics housing contains the power elements, the
control unit, and the mechanical pitch control system [see
Figure 2(a)]. The electronics housing is a polycarbonate
waterproof Bulgin box enclosure with two mounting holes
that are used to connect to the remainder of the assembly. The
primary electronic components include an Arduino Pro Mini
microcontroller, a RFM22B radio transceiver, and a 2,200
mAh 7.4 V Traxxas LiPo battery. The microcontroller is
selected for its size, simple interface, and limited cost.
The RFM22B radio transceiver, which communicates at an
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