IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10.
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Autonomous Spherical Mobile Robot for Child Development Studies François Michaud, Member, IEEE, Jean-François Laplante, Hélène Larouche, Audrey Duquette, Serge Caron, Dominic Létourneau, and Patrice Masson
Abstract—This paper presents the design process of a spherical robot capable of autonomous motion, and demonstrates how it can become a tool in child development studies. The robot, named Roball, is capable of intentional selfpropelled movements and can generate various interplay situations using motion, messages, sounds, illuminated parts and other sensors. Such capabilities allow Roball to interact with young children in simple and interesting ways, and provide the potential of contributing to the development of their language, affective, motor, intellectual and social skills. Trials done with 12 to 24 month old children demonstrate how Roball can be used to study children’s interest in a self-propelled and intentional device. An experimental methodology to conduct such studies is presented: it is based on quantitative and qualitative techniques to evaluate interactions, thus enabling the identification of challenges and opportunities in child-robot interaction studies. Index Terms—Children, Interaction studies, Mobile robot, Pediatric toy.
I. INTRODUCTION LAYING is a fundamental part of a child development. It simultaneously involves motor, cognitive and affective skills, mutually influencing each other and each being necessary for the evolution of the other. Play situations are linked to this development and, at the same time, contributes to it. [1]
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Manuscript received August 1st, 2004. This work was supported in part by the Canada Research Chair (CRC), the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canadian Foundation for Innovation (CFI). F. Michaud holds the Canada Research Chair in Mobile Robotics and Intelligent Autonomous Systems. He is with the Department of Electrical Engineering and Computer Engineering of the Université de Sherbrooke, Québec CANADA J1K 2R1 (phone: 819-821-8000 x 2107; fax: 819 8217937; e-mail:
[email protected]). Contact author. Jean-François Laplante and Patrice Masson are with the Department of Mechanical Engineering of the Université de Sherbrooke, Québec CANADA J1K 2R1 (e-mail: {JeanFrancois.Laplante,Patrice.Masson}@USherbrooke.ca). Hélène Larouche is with the Department of Education of the Université de Sherbrooke, Québec CANADA J1K 2R1 (e-mail:
[email protected]). Audrey Duquette is with the Department of Psycho-Education of the Université de Sherbrooke, Québec CANADA J1K 2R1 (e-mail:
[email protected]). Serge Caron and Dominic Létourneau are with the Department of Electrical Engineering and Computer Engineering of the Université de Sherbrooke, Québec CANADA J1K 2R1 (e-mail: {Serge.Caron, Dominic.Letourneau}@USherbrooke.ca).
Associated with playing is the capability of perceiving movement, which appears to be innate in humans [2]. With five months old children, studies showed that they prefer a moving image of a female face to that of a static one or one simply expressing emotions [3]. Many other studies confirm that from two weeks of age, children prefer looking at moving stimuli rather than stationary ones, even if they are identical in every other aspect [4, 5, 6]. Baron-Cohen's theory of mind also suggests that one basic form of perceptual information is based on self-propelled motion of stimuli [7]. Premack [8] advances the hypothesis that the perception of intentionality in moving elements is innate to humans. An infant divides the world in two classes of objects, i.e., whether or not it is selfpropelled. For self-propelled objects, an infant has the ability to distinguish the objects that can generate a change in their movements, with or without the assistance of another [9]. In the case of an autonomous change (which excludes however cyclic movements such as those associated with a bouncing ball), Premack suggests that infants perceive intentionality and show preference toward these objects. While adults can identify the nature of a self-propelled object and associate intentionality to it, for infants what matters is not the object but the type of movements it generates [10] and its velocity [11, 12]. In these previous studies, the objects used are photos and videos of human faces or simple geometrical shapes. To our knowledge, no research has been conducted with moving objects placed in real life settings. It would therefore be interesting to have a mobile device that can demonstrate such intentional self-propelled motion and use it to study different elements of child development theories. Common selfpropelled toys (e.g., moving trucks) move in pre-set directions or are teleoperated. An autonomous mobile robot however is certainly capable of intentional self-propelled motion in the world, avoiding obstacles and deciding what to do based on the sensed situation and its internal states. Such hypothesis are valid only if the robot can move in real life settings with all kinds of obstacles present and without getting stuck or flipping over, disabling the device completely. The robot must also be robust enough to sustain interplay situations (usually involving grabbing and throwing) with young children while being safe and simple to understand, all at a minimal cost. The solution we devised is to design a spherical mobile robot named Roball. The concept consists of encapsulating the robot inside a sphere and to use this sphere to enable the robot
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10. to move around in the environment. The robot, being spherical, can navigate smoothly through obstacles, and create simple and appealing interactions with people. The encapsulating shell of the robot helps protect its fragile electronics (sensors, actuators and processing elements). Roball’s first prototype was used in a set of trials aimed at observing how children interacted with the robot in unstructured familiar settings. Observations confirm that purposeful robot movements, its physical structure and locomotion dynamics can lead to interesting games influenced by environmental settings and the child's personality [13]. These observations encouraged us to design a second Roball prototype specifically developed to be a toy, and to explore the idea of how it can be used in child development studies. This paper presents the results of this work and is organized as follows. Section II describes the characteristics of the second Roball prototype and the design methodology involved in producing this prototype. Section III presents the different aspects in which a mobile robot such as Roball can influence skill development within infants and toddlers. It also describes trials conducted with toddlers aged 12 to 24 months, and the results obtained from quantitative and qualitative evaluations of the interactions. Section IV identifies the lessons learned from an engineering and experimental perspective in applying Roball in child development studies, followed with the conclusion. II. ROBALL THE SPHERICAL MOBILE ROBOT TOY As shown in Fig. 1, the first Roball prototype is constructed using a plastic sphere (bought in a pet store): it consists of two halves that are attached to each other [13, 14]. It is 6 inches in diameter and weighs about 4 pounds. The robot is made of an internal plateau on which all components (motors, sensors, microcontroller, etc.) are attached. Two DC motors are located on the side of the plateau, perpendicular (on the horizontal plane) to the front of the robot. These motors are attached to the extremities of the spherical shell. Turning in the same direction, they move the center of gravity of the internal plateau forward or backward, for longitudinal robot motions. Motor speed is regulated according to longitudinal inclination of the internal plateau, keeping the robot’s center of gravity close to the ground. Steering is achieved using a counterweight (a 12V 1.2Ah nonspillable rechargeable SLA battery) mounted on a servo-motor. This allows the robot to tilt on one side or the other as the shell rolls. Tilt sensors are used to provide inclination measures for longitudinal inclination and lateral inclination. Fig. 2 illustrates Roball’s locomotion principle. Roball was programmed to follow a deterministic play routine involving moving and stopping cycles. Roball also requests interactions with the child such as pushing, shaking or spinning. These requests are communicated using pre-recorded vocal messages stored on an ISD ChipCorder, a single chip device for voice recording and playback.
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Fig. 1. First Roball prototype (left) and a 10 months old infant interacting with Roball (right). Propulsion Motors
Steering Motor
Plateau
Counterweight a) Front / Back view
b) Side view
Fig. 2. Roball a) Both front or back view, b) side view. The steering motor moves the counterweight from one side to the other in order to move the center of gravity away from the center of the sphere. The propulsion motors make the center of gravity move upward from one side or the other of the rolling axis, making it move forward or backwards.
Designing the second Roball prototype as a toy requires a much more sophisticated design process. Our methodology is based on concurrent engineering principles [15] and has six general phases: 1) Requirement analysis (identify user needs, operating conditions and project constraints). After consulting with experts in child development, 6 to 24 months old children were determined as the target audience for the robot toy. At this age, mobility is a more predominant factor in interplay situations, before they start engaging in role playing games. Section III describes in more detail the potential associated with the use of a mobile robotic toys for this age group. Analysis of consumer toy reviews also allowed us to identify a list of requirements for toys targeted at this age group, such as: Technical requirements: robust, safe, solid, light, low energy consumption, affordable price, quiet (volume control), washable and easy to use. Child development requirements: encourage the young child to move, crawl and manipulate, be visually stimulating, create interesting interactions with the child. 2) Functional analysis (translation of the requirements into functional terms for organization and analysis). Based on what we have learned from the first Roball prototype, we developed a list of feasible functions and criteria for the second prototype that addressed the requirements outlined in phase 1. 3) System design (elaborate and analyze general concepts addressing the identified functions). We developed four new
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10. design concepts for the shell and the counterweight mechanism. Each concept was evaluated based on the requirements outlined using a tool called a Criteria Based Matrix or Pugh Matrix. 4) Preliminary design (elaborate and analyze specific concepts for the different subsystems of the selected general concept). The different mechanical and electrical subsystems of the selected concept were identified and examined. One side of the second Roball prototype is designed to create a face interface for interacting with children, as shown in Fig. 3. This interface consists of a three-way button for activation and volume control of the robot, a microphone, a speaker, two illuminated push buttons, illuminated eyebrows using LEDs, one infrared proximity sensor and one photodetector sensor.
Fig. 3. Roball’s
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illumination condition of the environment or the proximity of something near its face interface. 6) Integration and validation (fabrication and assemblage of all of the parts, and test according to the requirements and functions). The new shell was designed to allow easy access inside the sphere in order to replace the batteries. A small handle was incorporated in the face interface to facilitate the removal of the structural element holding the batteries. The new shell also provides a transparent surface in the middle of the sphere to allow the use of a proximity sensor facing forward. This surface does not touch the floor as the robot rolls: this results from the shell having two points of contact with the ground, making it move perfectly straight. However, since the transparent surface was not required in these initial trials, a circular band was placed on top of it to make the shell completely spherical. Due to budget constraints, the fabrication of the mechanical subsystems for this prototype was produced using Rapid Prototyping in ABS plastic (acrylonitrile-butadiene-styrene copolymers). This made the shell thicker, heavier (also making the robot slower) and although more robust than the first prototype, it is not as robust as it would have been if produced with thermoplastic manufacturing. The shell was painted with bright colors (red, yellow and blue, typical toy colors). Unitary and integration tests of the design were completed successfully, and the overall result is shown in Fig. 4.
face interface, or face.
Another innovation is that the steering mechanism of the second Roball prototype allows the counterweight (now four standard type C batteries) to move over 250°. This allows the robot to flip over onto one side, making face upward, or to flip completely to the other side. While standing with the face interface facing upward, the robot can rotate on the spot and create a spinning movement. A circular flat surface was designed on the opposite side to the face interface, to facilitate moving into this position. Custom designed inclinometers are used to perceive the longitudinal and lateral angles of the internal plateau. 5) Detailed design (for each subsystem, calculations, drawings, schematics and technology choices are made to produce the prototype). Design tools, such as SolidWorks for technical drawing and Nastran for mechanical simulation, were used. We designed the shell as though it were intended to be manufactured using thermoforming technologies, just like regular toys. An onboard MicroChip PIC18F microcontroller programmed in C is used to allow the robot to achieve specific motion patterns (forward, backward, turning left or right, spinning, specific trajectories such as eight-shape, spirals, etc.). This system also allows the robot to interact with the child using pre-recorded messages and sounds (generated and stored on a ISD ChipCorder), by illuminating the parts of its face interface, detecting claps, detecting the
Fig. 4. Second Roball prototype.
III. CHILD-ROBOT INTERACTIONS WITH ROBALL For validation purposes, one challenge still remained once the design of the second Roball prototype was completed: evaluating its use as a mobile device for interaction with children. Task-oriented metrics such as those used to evaluate service robots or human-computer interfaces [16, 17] are not appropriate for such an evaluation: Roball does not have a specific goal to achieve with a clear outcome (like cleaning a room, finding a victim, etc.); interactions with people are more subtle influences to measure, especially with infants and toddlers who are in the process of learning and discovering everything about the world. From 0 to 24 months of age, child development is mostly oriented toward the acquisition of general sensori-motor skills. Roball’s self-propelled intentional locomotion capabilities
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10. may have many benefits during this developmental phase. The work conducted during the requirement analysis phase of the design process identifies the potential influences and benefits a robot such as Roball may have during child development period, especially between 6 and 24 months of age [18]: 1) Motor skills. From 6 to 12 months of age, Roball’s motion can be an incentive for the child to follow the robot (by crawling or walking). It can also develop the child’s visual skills (for tracking an object or using visual effects), and its internal temporal model of the existence of objects in the world. At 12 to 18 months, Roball may contribute to the development of global motor skills, generate situations for precise manipulations of the robot (like for grasping Roball, making it spin or by pushing it, or also by using the push buttons). From 18 to 24 months, Roball could help develop balancing skills as the child becomes capable of standing and follows the robot by walking. 2) Intellectual skills. Between 6 to 18 months, in addition to helping create a temporal model of the existence of objects in the world, the child could unwittingly explore trajectories and the effects of different actions while playing with Roball. At 18 to 24 months old, the child should be able to associate the right response to a request made by the robot, therefore possibly encouraging the child to initiate symbolic games (associating Roball with something from his or her imagination). 3) Social skills. From 6 to 12 months old, the activation of Roball would most likely require an adult’s presence to start the robot and in the interplay situations. Adults could comment on the effects of the robot as it moves autonomously in the world and interacts with the child, thus using Roball as an intermediate between the two. At 12 to 18 months, the child’s attention should be more focused on the robot than on other children, while at 18 to 24 months old the child should enjoy sharing his or her experience with others. At this age, the child can start to try to imitate the robot in its actions and its messages. 4) Affective skills. From 6 to 12 months old, the child can exhibit a preference towards Roball, either liking or disliking it, being intimidated by its presence or its unfamiliar voice. Between 12 to 18 months, Roball may help to develop positive self-esteem within a child by the constructive reinforcement provided by the robot itself, or through a parent as the child plays with the robot. From 18 to 24 months old, the child has the ability to experience joy when congratulated by Roball. 5) Language skills. From 6 to 18 months old, Roball may influence the child’s language skills by expressing simple words such as “Yes”, “No”, “Yippee”. Eventually the child may express the desire to play with Roball through verbal requests. Between 18 to 24 months old, a child’s vocabulary is developing and the child can repeat what Roball is saying, understand simple requests made by Roball (like “push me”) and learn new words from the robot. Overall, Roball possesses the potential to bring new and interesting opportunities for a variety of different studies regarding child development. However, the project was
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initiated from an engineering perspective, therefore the emphasis of the design process – Phase 6 was focused on validating the robot in use and not on the actual impact it has on children: this will follow once the design has shown to be usable in such context. Note that since trials involving mobile robots and toddlers are themselves still in their infancy, conducting such preliminary studies allows us to outline interesting challenges for new research opportunities. Discoveries, both from an engineering perspective and from an experimental point of view, will hopefully create interest from researchers in child development. Toddlers of less than 24 months old represent a very special evaluation population within human-robot interaction domain: they have no a priori knowledge of what a robot is and how to interact with it, nor is it possible to provide pre-trial instructions. So even if careful experimental procedures are put in place, anything can happen during these trials. Therefore, the benefit of the following results relies more on the lessons learned from conducting trials related to child development, rather than on the scientific proof regarding the contributions of Roball in child development. The best way to evaluate human-robot interactions, in our case occurring between toddlers and Roball, is still an open question. Interaction study is a complex area of research with a great variety of experimental methodologies [19, 20, 21]. Interactions are dynamic processes that can be characterized from observations. Quantitative evaluation of observational data typically consists of manual coding, on a second-bysecond basis, of specific interaction modalities so that statistical techniques can be applied to data gathered from a test population [22, 23]. Observational data can also be characterized by descriptive narratives relating the interactions that occurred, providing more insights on why or what caused them to emerge. Since each child has his or her own way of interacting with toys, and at this age it is not possible to interview them afterwards to understand the reason why they behaved the way they did during the trials, both quantitative and qualitative evaluations can provide rich insights on the influences a robot can have on young children. But each of these types of experimental methodology is a research area of its own, making it hard for roboticists to make an educated guess in selecting the best one for a particular design. So, in this work, we present both types to illustrate their use, their benefits and the challenges in the evaluation of toddler-robot interactions. A. Research Hypothesis and Experimental Protocol Since it is between 12 to 24 months of age that children begin to understand the different interactions generated by Roball (its motion and the generated messages), it was decided to conduct trials with this age group. Also, as we had previously conducted experiments with Roball’s first prototype in children’s natural living environments and with an experimenter well known to the child, we chose this time to conduct the trials in a more formal setting and with toddlers not familiar with the experimenter. We conducted our trials in a kindergarten school with two different groups of four children, one between 12 to 18 months old (three girls
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10. and one boy) and the other between 18 to 24 months old (three girls and one boy). During the trials, the experimenter and one educator (one for the 12-18 months old group and one for the 18-24 months old group) were present in the room with the child and Roball. The roles of the educator were to provide a familiar presence and to encourage the child to play with Roball while limiting distractions by external influences. We formulated two hypotheses to explore in these trials : 1) Roball’s intentional self-propelled motion should increase the child’s attention level towards the robot. 2) Playing with Roball should increase the toddler’s mobility. This hypothesis is based on the fact that a child has a natural tendency to grasp an object in motion [24]. Our experimental protocol attempted to separate the influencing factors of the child interacting with Roball. It is based on individual case evaluation during which Roball is presented to the child in different modes, named A and B respectively, each lasting 120 seconds. In mode A, Roball is set to interact through the use of lights and vocal messages only, without moving. During the first 30 seconds, the face interface of Roball is facing upward and the robot asks the child to either shake it, push it or spin it. If the appropriate response is taken, then Roball congratulates the child by saying either “Yippee”, “Thanks”, “Weee” or “I love you”. For the next 30 seconds, the robot just reacts to physical contact with the child by illuminating its eyebrow and its push buttons. Mode A then repeats itself for another 60 seconds. In mode B, Roball moves autonomously in the environment for 60 seconds, periodically turning to the right to approximately stay in the same area. When it hits an obstacle, Roball stops, backs up and turns. During the next 60 seconds, Roball stops, positions itself to have its face interface facing upward, asks the child to play with it and reacts to physical contact in a similar manner to Mode A. This encourages the child to grab the robot and remain close to it. According to Premack [8], the child should be able to attribute self-propelled capabilities once having seen the robot intentionally moving, and this association will continue even when the robot has stopped. One day the robot was set to exhibit mode A and then mode B; the next day the robot started with mode B followed with mode A: this type of experimental protocol is identified as AB / B-A [25]. It took four days to conduct the experiments (one for each group and experimental protocols A-B and B-A). Before beginning the trials, time was allowed for the toddler to familiarize itself with the presence of the robot, the environment and also the experimenter. Trials were conducted in the morning over a two-week period. The experimental methodology consisted of filming the interactions between the child and Roball, the camera being held by the experimenter to provide the best possible view of the interactions. These interactions were then analyzed afterwards using a quantitative and a qualitative evaluation methods, as described in the following subsections. B. Quantitative Evaluation We applied a second-by-second analysis technique as those used in [25, 26, 27] to measure the manifestation of three micro-behaviors, i.e., the amount of time the child was
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looking directly at Roball (Gaze Direction), making physical contact with Roball (Physical Contact), and moving toward Roball (Displacement).
Fig. 5. Scatter plot of the observed gaze direction of the children toward Roball, compiled for A-B protocol and B-A protocol.
Fig. 6. Scatter plot of the observed physical contact by children with Roball, compiled for A-B protocol and B-A protocol.
Figures 5 to 7 show the time of observation of these microbehaviors in relation to the mode of Roball, for each of the eight children, over 120 seconds. Both the horizontal and vertical axes are timed in seconds. The arrows indicate the change observed from implementing the A-B protocol in day 1, and then the B-A protocol in day 2. The two diagonals shown on each graph allows identification of when the observation time of the micro-behavior is significantly longer (by 10%, as indicated by the upper diagonal) for mode B (Roball is in motion) than for mode A (Roball is not moving), or significantly smaller (by 10%, as indicated by the lower diagonal) for mode B than for mode A. For instance, looking at the grey diamond of Figure 6, in day 1 the observed time of the child’s gaze direction toward Roball were 84 sec in mode A, and 44 sec in mode B: the point is therefore situated below the lower diagonal. In day 2 the observed time were 72 sec in mode A and 90 sec in mode B:
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10. this places the point above the higher diagonal. Points above the higher diagonal indicates that the micro-behavior was observed more Roball was self-propelled (mode B) compared to when it was not (mode A). Note that two results are missing: one caused by a mistake when handling the video, and the other is that one child chose not to play with Roball: he wanted to go back to the activity he was doing before the trial. No significant differences in the observations were seen between the two groups of children, therefore we display the results of the two groups on the same plots. In Fig. 5, regardless of how the children were exposed to Roball (in either A-B or B-A protocols), for half of the group gaze direction was greater than or equal to when Roball was in mode B (self-propelled) compared to when it was in mode A (not moving). Only one child had comparable results for both A-B and B-A protocols. Note that children spent a lot of time looking at Roball in modes A and B, showing their interest in the device. However, over 120 seconds (which is a relatively small amount of time), it was difficult to get good discrimination of gaze direction when the robot is selfpropelled compared to when it is not. Fig. 6 shows that in about 50% of the cases, the children grasped and touched Roball while the robot was in mode B. Two children (grey square and grey circle) preferred touching the robot while it was not moving, in both the A-B and B-A protocols. Fig. 7 provides no clear conclusion regarding the displacement of children when Roball was self-propelled compared to when it was not.
Fig. 7. Scatter plot of the observed displacement of the child, compiled for A-B protocol and B-A protocol.
C. Qualitative Evaluation Looking closely at the trial videos, it is clear that each child interacted very differently with Roball: they all have their own personality and interests and are not at the same development stage even if they are the same age. Depending upon what happened during the trials, the educator also at times helped or intervened: their presence was necessary but influenced the results. To better understand these factors, we qualitatively describe and analyze the interactions that took place between Roball and each child, for each day of the trials
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(day 1 with protocol A-B, and day 2 with protocol B-A). The observations are referenced by day and Roball’s mode. Grey diamond (girl, 12-18 months old). During all the trials, this child periodically sought reassurance from the educator when interacting with Roball. At first during day 1 and when in mode A, Roball got her attention every times it made a sound. She played with the robot by pushing it. When Roball moved (mode B), she pursued the robot by walking, leaning and pushing the robot using her hand. She however always wanted to remain close to the educator and to be held. The educator invited her to pursue playing with Roball, without success. In the second day, she looked at Roball only when it was moving. She did not move a lot at first because Roball was constantly coming toward her by itself, but she pushed the robot when it came close to her. Roball at one point stopped coming toward her, and eventually she moved toward the robot by remaining in a seated position. When mode A was activated on day 2, she complained (using verbal sounds) that the robot was not coming toward her. She did not went to play with the robot by herself, and more frequently sought the approbation of the educator before playing with Roball. The educator directed her attention toward Roball by bringing it to her, playing with her and pointing out what the robot was saying. White circle (girl, 12-18 months old). This child was very curious and active. She constantly followed and pushed the robot around (right picture of Fig. 8), which made it difficult to observe a change in her behavior throughout the trials. The only clear distinction observed between modes A and B is when she kicked the robot. Her first attempt to kick Roball day 1 during mode B was not successful because Roball moved before she could kick it; she then pushed the robot with her hand. Also during day 1 mode B, in a second attempt after having fell and crawled toward the robot, she stood up and decided to hold on to a table before kicking Roball. She laughed and made verbal sounds every time something happened to the robot. She showed great interest toward Roball’s face: when Roball was in mode B, she stopped the robot from moving to have a better look at its face. Grey square (girl, 12-18 months old). Every time Roball’s behavior changed or before making an action, this child visually sought approbation with the educator. During day 1, she remained close to the educator and needed reassurance before starting to play with Roball. While Roball was in mode A, her fear changed to curiosity and fascination towards Roball’s face. She vocally responded every time Roball made a sound, but did not show interest when the robot was moving on its own: her attention was directed on other things. During day 2, starting with mode B, she kept looking at the robot while it was moving. She did not try to catch it or follow it: when Roball came close to her, she slowly backed away so as not to interfere with the robot’s trajectory. With Roball in mode A, she kept looking at the robot waiting for it to start moving again; the educator had to bring her near the robot and she then
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10.
started to play with Roball’s face. Grey triangle (boy, 12-18 months old). This child had a very high level of attention toward the robot, but remained seated (left in Fig. 8) or still without verbalizing for the most part of the trials. During day 1, he got to play with Roball’s face when the robot was in mode A. In mode B, he learned to hold the robot with one hand, and played with Roball’s face (trying to stabilize it holding its handle) with the other. He sometimes released Roball briefly to see if it would move away. When Roball started in mode B during day 2, this child was seeing that Roball was moving but did not want to look at it directly. When Roball came close to him, he grabbed it and repeated the play activities as before. With Roball in mode A, the child just kept looking at its face, without moving or making the robot moved.
Fig. 8. Boy (left) and girl (right) interacting with Roball.
White diamond (girl, 18-24 months old). This girl mostly played with Roball by remaining seated and by holding the robot on her legs or in her arms. This way, she remains in control of Roball’s position when mode B was activated, and was able to play with its face. One interesting observation occurred during day 2 with the robot in mode A. At the encouragement of the educator, she started to push the robot around; she crawled to pick up the robot and came back to seat near the educator, playing with one hand on Roball while looking toward the educator. Holding Roball on her legs while it was in mode B, her attention was constantly directed toward the robot when it was trying to move. White triangle (boy, 18-24 months old). During day 1, this child imitated the robot by rolling on the floor. With Roball in mode A, his first action was to kick the robot and to play with its face, leaning over to talk to Roball. Seeing it roll made him want to do the same. In mode B, he continued to roll of the floor and eventually put his legs over Roball, pretending that the robot was hiding. He then released the robot, said “Cuckoo” and kept looking at Roball as it moved away: he went to pick up the robot and brought it back to the educator. With the robot in his arms, he looked closely at Roball’s face that was turning (the robot was still trying to move). Once the robot was back on the floor, he held back kicking the robot and watched it move away before going to catch it. He interacted more verbally with Roball in mode B, and even gave it a kiss on the “cheek”. Starting in mode B during day 2, he continued following the robot and catching it, holding back kicking it when he saw Roball
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moving. He kept trying to put the robot away in a box so that it could not get away. In mode A, with Roball not moving, he did not move to go pick it up. He just wanted the robot to remain in its box. Grey circle (girl, 18-24 months old). This child smiled the entire time she interacted with Roball. With Roball in mode A during day 1, she carefully looked at its face and went to pick up and bring the robot back after the educator had made it roll on the floor. In mode B, she remained seated and stood still, watching the robot move around. Once it stopped, she requested that Roball continued. She clearly enjoyed looking at the robot while it moved. During day 2, starting in mode B, Roball coming toward her made her smile. She kept the robot close to her while watching it move. She verbalized when Roball stopped moving, and she went to push the robot when requested. She then crawled to get and bring it back to the educator. She however got distracted quite a bit during this trial by other activities nearby. In mode A, she responded to Roball’s request to push it or to play with it, but did not move a lot. She remained on one knee leaning over Roball and playing with its face. symbol (girl, 18-24 months old). This child frequently had to practice her ability to crawl, to stand up and to walk during these trials. Encouraged by the educator, she pushed Roball and brought it back to the educator twice during day 1, with Roball in mode A. In mode B, she closely watched the robot moving on its own and went to grab it. She placed the robot in between her legs and played with Roball’s face that kept turning. It appears that she was trying to move the face to the correct position. When Roball stopped moving, she seemed to loose interest toward the robot and released it. As it started to move again, her attention was drawn back. As the robot came close to her, she grabbed it and pushed it to the left. As to robot continued to move, she went to catch it by remaining in a seated position. She put her legs over it and made Roball roll without letting it go. In this position she did not look at the robot. During day 2, she remained still while observing Roball move. She stretched her hand toward the robot, but did not move to get it. She seemed a bit upset because she wanted to play with another friend. She kept looking at the robot when it was moving; when it was not, she was asking the educator about her friend. With Roball in mode A, the educator helped direct her attention to the robot by tossing it around and bringing it to her. She turned around on herself as the robot went behind her in a circular motion after being pushed by the educator. She pushed the robot but did not want to go and grab Roball. The educator had to encourage and help her frequently. While these observations confirm many potential influences of Roball regarding child development, two additional comments can be derived from these evaluations: Roball’s face and sound generating capability made it an interesting toy to children. The fact that Roball spoke made some children feel uncomfortable at first, but this
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10.
became a source of interest once they were familiar with the device. The presence of an educator during the trials is important in that regard, because it helped regulate the children’s behavior. The educator was also able to put emphasis on what the robot was saying (by repeating what Roball said) and doing (using words to characterize the particular situation like “The ball is leaving” for instance). The buttons and the lights also attracted the children’s attention. Roball’s dynamics, either when being pushed or moving on its own, generated interest. Roball does not move like a regular ball because its center of gravity is off-center and changing. Children’s interest in Roball’s dynamics was manifested in different ways: looking at the robot without moving, going to catch the robot, holding it so that it did not move away, etc. This partially explains why it was difficult to develop conclusive observations from the quantitative results presented in Section III.B. It also justifies the importance of qualitative evaluations, without which interesting results would not have been reported. For instance, this is how we identified that children played with Roball by trying to hold its face still while it tried to move. This game emerged from holding Roball’s shell, which makes the robot move by trying to get away from this difficult position. IV. LESSONS LEARNED
First, these trials allowed us to identify technical limitations of the second Roball prototype. For instance, some children may have difficulties understanding the robot’s verbal requests. Even though the second Roball prototype design improved the audio capabilities, it may be necessary to exaggerate word pronunciation to help compensate for the 8 kHz sampling rate of the ISD ChipCorder. Additional tests are required to validate this observation. It is not that obvious from this test that children did not understand the requests, they simply may not have complied. The handle designed on Roball’s face interface also caused the robot to sometime become stuck on this side. Roball’s robustness was put to the test when one active girl (white circle) threw it roughly on the concrete floor. The structural element holding the batteries to the internal chassis was damaged, pinpointing a weakness in the design of this element (also caused by the fabrication process). Finally, the decision to make Roball periodically turn to the right to remain in the same area did not make children move quite as much as it would have been prefered. All of these limitations can be easily corrected during the design of a third prototype, this time produced with thermoplastic manufacturing. This type of manufacturing will also make the shell lighter and improve the robot’s dynamics. Second, we have learned that conducting trials with toddlers and mobile robots is highly challenging. Adding mobility to the toy increases the unpredictability of situations that occur. Quoting Robins et al. [27], “the effort to realize user studies with robots is immense and poses significant obstacles to the advancement of research in the field”. Inconclusive results can occur, especially when each child is
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not frequently exposed to the robot and when there is explicit encouragement by an educator present [26]. The child’s mood then becomes a factor that can influence the observed interactions. In addition, having such a short exposure time (4 minutes per child) adds to the difficulty of ensuring each child has enough time to recognize that Roball is capable of selfpropelled motion. Complicating the understanding of this for the child is that the robot moved even in mode A, as the child and the educator played by making it roll on the floor or by tossing it to one another, thus creating motion. This situation may not have occurred with a wheeled robot. The conditions in which the trials took place also had an influence over the results. Children were taken one by one away from their group, stopping what they were doing to play in a room that they were not used to. No other room was available, and a variety of events happened nearby such as people moving, the experimenter holding the camera, the child could hear sounds and scents coming from the kitchen and from other children playing in the other room, etc. In fact, just the presence of the experimenter required him to spend half a day playing and interacting with the children to familiarize children with his presence. A final factor is that the educators, although they understood the experimental protocols, did not always intervene in the same manner with each child. Rather they adapted to the child’s mood and needs. Some of these factors could have been better managed to improve the evaluations. Obviously, child development studies go far beyond the expertise of roboticists. In our case, our engineering team, with no previous experience in human experimental studies, conducted the trials. However, people outside of robotics rarely have a realistic idea of how mobile robot be used. So, exposing robots such as Roball in a child development study is a discovery process and a demonstration of challenges and opportunities for both roboticists and child development experts, seeking and fostering strong collaborations between the two disciplines. The work presented by Besio [28] regarding the use of assistive technology to allow children with motor disabilities to play with toys is a good example of the benefits that can come from the cross-fertilization of both disciplines. From our study emerges the possibility and the feasibility of interesting child development studies involving Roball. For instance, Roball could be used to study the independence of motion and form of objects in catching the attention of young children, or comparing the interactions of young children playing with Roball in motion, Roball not moving, and a ball-shaped toy. Such studies would be related to Heider and Simmel’s work [29] identifying that motion by itself is thought to be sufficient to create complex social attributions. Draper and Clayton [30] demonstrated that children paid more attention to either a live teacher and to a moving robot giving them instructions, than compared to a stationary robot. Kahn et al. [31] also showed that children differ in their behavioral interactions between a robotic dog and a stuffed dog. Other studies involving the different interactive capabilities of Roball (sounds, messages, lights and sensors) could also be realized. Conducting trials over a longer period (both in duration and number of exposures) with
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10. children in their natural living environments and in a more unsupervised manner (e.g., reducing the intervention of the educator) would also be very interesting. Another interesting experimental setup would be to put two Roballs in a room, one in mode A and the other in mode B, to see which one interests children the most. All of these suggestions can only be made possible by having a fully functional Roball prototype and an active team of child specialists to conduct these studies. The lessons learned during the present work greatly contribute to eventually reaching this objective. V. CONCLUSION Designing mobile robots to interact with young children in unconstrained conditions undoubtedly provides interesting challenges. In this paper, we have presented the second Roball prototype, an autonomous spherical mobile robot designed specifically for such use. Mobile robots being a new technology, their design remains an iterative process that requires developing prototypes and testing them in real situations. These iterations also call for strong collaborations between engineers and education experts in order to increase the benefit of the work. Human-robot interaction is a young and very rich source of novel ideas, challenges and scientific contributions in both engineering and human sciences [32], respectively and at their frontiers. An interdisciplinary team working on this topic is emerging from this work, hoping to make valuable contributions to the field of socially interactive robotics [33]. ACKNOWLEDGMENT The authors would like to thank the Centre de la petite enfance Tout petit, toute petite, Sherbrooke Québec, for their participation in the experiments. We also want to thank François Larose and Johanne April for providing advices regarding the trials done with children, and Tamie Salter for her help in revising this manuscript. Finally, many thanks to the reviewers for their helpful and detailed comments. REFERENCES [1] J. Guillemaut, M. Myquel, and R. Soulayrol, Le jeu, l’enfant, Paris, Expansion Scientifique Française, First Edition, 1984, 239 p. [2] P. Salapatek and L. Cohen, Handbook of Infant Perception Volume 2: From Perception to Cognition, New York, Academic Press Inc., 1987, pp. 123-149. [3] B. M. Wilcox and F. L. Clayton, “Infant visual fixation on motion pictures of the human face,” Journal of Experimental Child Psychology, vol. 28, pp. 158-173, 2001. [4] L. R. Sherrod, “Social cognition in infants: Attention to the human face,” Infant Behavior and Development, vol. 2, pp. 279-294, 1979. [ 5 ] C. A. Nelson and F. D. Horowitz, “The perception of facial expressions and stimulus motion by 2- and 5-month old infants using holographic stimuli,” Child Development, vol. 54, pp. 866-877, 1983. [6] G. Carpenter, “Visual regard of moving and stationary faces in early infancy,” Merrill-Palmer Quaterly, vol. 20, pp. 181-194, 1974. [7] S. Baron-Cohen, Mindblindness, MIT Press, 1995. [8] D. Premack, “The infant’s theory of self-propelled objects,” Cognition, vol. 26, pp. 1-16, 1990. [9] M. D. Hauser, “A nonhuman primate’s expectation about object motion and destination: The importance of self-propelled movement and animacy,” Developmental Science, vol. 1, no. 1, pp. 31-37, 1998.
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[10] R. Sekuler, “Visual motion perception,” Handbook of Perception: Volume 5 – Seeing, E. C. Carterette and M. P. Friedman (Eds), Academic Press, pp. 387-430, 1975. [11] R. N. Aslin and S. L. Shea, “Velocity threshold in human infants: implications for the perception of motion,” Developmental Psychology, vol. 26, pp. 589-598, 1990. [12] J. L. Dannemiller and R. Freeland, “The detection of slow stimulus movement in 2- to 5- month olds,” Journal of Experimental Child Psychology, vol. 47, pp. 337-355, 1989. [13] F. Michaud and S. Caron, “Roball, the rolling robot,” Autonomous Robots, vol. 2, no. 12, pp. 211-222, 2002. [14] F. Michaud and S. Caron, “Roball – the rolling robot (Patent style),” U.S. Patent #6,227,933, May 8, 2001. [15] K. T. Ulrich and S. D. Eppinger, Product Design and Development, Prentice Hall, 2000. [16] E. Messina, A. Meystel, L. Reeker, “Measuring performance and intelligence of intelligent systems,” Proceedings of the Performance Metrics for Intelligent Systems Workshop, White paper, 2001. [17] H. A. Yanco and J. L. Drury, “Classifying human-robot interaction: An updated taxonomy,” in Proceedings IEEE International Conference on Systems, Man, and Cybernetics, 2004. [18] J. April, “Enfants de 0-6 ans: réalités familiales et sociales,” Course Notes, Faculté d’éducation, Université de Sherbrooke, 2002. [19] T. Kanda, T. Hirano, D. Eaton, H. Ishiguro, “Interactive robots as social partners and peer tutors for children : A field trial,” HumanComputer Interaction, vol. 19, no. 2, pp. 61-84, 2004. [20] J.P. Pourtois, H. Desmet, Épistémologie et instrumentation en sciences humaines, Bruxelles : Pierre Mardaga ed., 1997. [21] A. Tashkkori, C. Teddlie, Mixed Methodology. Combining Qualitative and Quantitative Approaches, Thousand Oaks (Cal.), Sage Publications, 1998. [22] C. Tardif, M.-H. Plumet, J. Beaudichon, D. Waller, M. Bouvard, and M. Leboyer, “Micro-analysis of social interactions between autistic children and normal adults in semi-structured play situations,” International Journal of Behavioural Development, vol. 18, no. 4, pp. 727-747, 1995. [23] K. Dautenhahn and I. Werry, “A quantitative technique for analyzing robot-human interactions,” in Proc. IEEE/RSJ Int. Conf. on Intelligent Robots and Systems, pp. 1132-1138, 2002. [24] C. von Hofsten, “Catching skills in infancy,” Journal of Experimental Child Psychology: Human Perception and Performance, vol. 9, pp. 7585, 1983. [25] R. Ladouceur and G. Bégin, Protocole de recherché en sciences appliqués et fondamentales, Edisem, Chap. 3, pp. 87-130, 1980. [26] B. Robins, K. Dautenhahn, R. te Boekhorst, A. Billard, “Effects of repeated exposure to a humanoid robot on children with autism,” in Proceedings Cambridge Workshop on Universal Access and Assistive Technology, Springer-Verlag, pp. 225-236, 2004. [27] B. Robins, K. Dautenhahn, R. te Boekhorst, A. Billard, “Robots as assistive technology – Does appearance matter?” in Proceedings IEEE International Workshop on Robot and Human Interactive Communication, 2004. [28] S. Besio, “An Italian research project to study play of children with motor disabilities: The first year of activity,” Disability and Rehabilitation, vol. 24, no. 1-2-3, pp. 72-79, 2002. [29] F. Heider and M. Simmel, “An experimental study of apparent behavior,” American Journal of Psychology, vol. 57, pp. 243-259, 1944. [30] T. W. Draper and W. W. Clayton, “Using a personal robot to teach young children,” The Journal of Genetic Psychology, vol. 53, no. 3, pp. 269-273, 1992. [31] P. H. Kahn, B. Friedman, D. R. Perez-Granados, N. G. Freir, “Robotic pets in the lives of preschool children,” in Proceedings of the Conference on Human Factors in Computer Systems, 2004. [32] B. Caci, A. d’Amico and M. Cardaci, “New frontiers for psychology and education: Robotics,” Psychological Reports, vol. 94, pp. 13721374, 2004. [33] T. Fong and I. Nourbakhsh and K. Dautenhahn, “A survey of socially interactive robots,” Robotics and Autonomous Systems, vol. 42, pp. 143-166, 2003.
IEEE Transactions on Systems, Man, and Cybernetics, 35(4):1-10. François Michaud (M’90) received his bachelor’s degree (’92), Master’s degree (‘93) and Ph.D. degree (‘96) in electrical engineering from the Université de Sherbrooke, Québec Canada. After completing postdoctoral work at Brandeis University, Waltham MA (’97), he became a faculty member in the Department of Electrical Engineering and Computer Engineering of the Université de Sherbrooke, and founded LABORIUS, a research laboratory working on designing intelligent autonomous systems that can assist humans in living environments. His research interests are in architectural methodologies for intelligent decision-making, design of autonomous mobile robotics, social robotics, robot for children with autism, robot learning and intelligent systems. Prof. Michaud is the Canada Research Chairholder in Autonomous Mobile Robots and Intelligent Systems. He is a member of IEEE, AAAI and OIQ (Ordre des ingénieurs du Québec). In 2003 he received the Young Engineer Achievement Award from the Canadian Council of Professional Engineers. Jean-François Laplante Jean-Francois Laplante recieved his bachelor's degree (‘01) and Master's degree (‘04) in mechanical engineering from the Université de Sherbrooke. He now works with the R&D team at DAP Technologies in Québec, designing rugged handhelds computers. His interests are in designing consumer electronics products like toys, robots, computers or mass market electronics products. M. Laplante is a member of OIQ. Hélène Larouche received her bachelor’s degree (’81) in preschool education at the Université du Québec à Trois-Rivières, her Master’s degree (’88) and Ph.D. degree (00) in psychopedagogy at the Université Laval. Since 2000, she is an Assistant Professor at the Université de Sherbrooke in teacher education, specifically in early childhood teacher education. Her research interests are in professional development, ethnomethodology in collaborative and action research, social interactions in child development. Prof Larouche is a member of OMEP-Canada (Organisation mondiale de l’éducation préscolaire) and also member of AÉPQ (Association d’éducation préscolaire du Québec). Audrey Duquette Audrey Duquette received her bachelor’s degree (’02) in psychoeducation and she is completing her Master’s degree (’05) in psychoeducation at the Université de Sherbrooke. Her research interests cover interventions using play, imitation and mobile robot for autistic children to improve their communication and social interaction. Since 2004, she is working at Ste-Justine Hospital as a psychoeducator performing assessments and followup of children between the ages of 0 to 5 years old, mainly with pervasive development disorders and autism. Miss Duquette is a member of OCCOPPQ (Ordre des conseillères et conseillers en orientation et psychoéducatrices et psychoéducateurs du Québec). Serge Caron Serge Caron received his college’s degree (’92) in computer systems from the Collège de Sherbrooke, Québec Canada. Since 1992, he is a technician in computer systems at the Department of Electrical Engineering and Computer Engineering of the Université de Sherbrooke and a member of LABORIUS since its foundation. His interests are in designing mobile robotic platforms, from four-legged to wheeled robots as well as other unconventional means of locomotion. He is also a writer for hobbyist robotic journals.
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Dominic Létourneau received his bachelor’s degree (’99) in computer engineering and his Master’s degree (’00) in Electrical Engineering from the Université de Sherbrooke. Since 2001, he is a research engineer at LABORIUS. His research interests cover combination of systems and intelligent capabilities to increase the usability of autonomous mobile robots in the real world. His expertise lies in artificial vision, mobile robotics, robot programming and integrated design. M. Létourneau is a member of OIQ. Patrice Masson received his bachelor's degree (’89) in Engineering Physics and Master's degree (’91) in mechanical engineering from École Polytechnique de Montréal, Canada. Patrice Masson obtained his Ph.D. degree (’97) in mechanical engineering from the Université de Sherbrooke, Canada. He has worked as a research assistant at École Polytechnique in 1991-1992 and since 1994, he has been with the Acoustics and Vibration Group at the Université de Sherbrooke (GAUS). He joined the Mechanical Engineering Department of the Université de Sherbrooke in 2000, where he is currently an Associate Professor. He has contributed to establish a new curriculum and is teaching the Mechatronics courses. His research interests include active noise and vibration control, smart materials, fiber optic sensors and signal processing. Prof. Masson is a member of the ASA (Acoustical Society of America), SAE (Society of Automotive Engineers), SPIE (International Society for Optical Engineering) and OIQ (Ordre des Ingénieurs du Québec).
