J Intell Robot Syst (2016) 81:41–49DOI 10.1007/s10846-015-0200-8

Experiential Learning in the Development of a DARwIn-HPHumanoid Educational Robot

Hak Yi ·Coleman Knabe · Taylor Pesek ·Dennis W. Hong

Received: 30 March 2014 / Accepted: 19 January 2015 / Published online: 25 March 2015© Springer Science+Business Media Dordrecht 2015

Abstract The purpose of this study is to present theexperiential learning in the development of a DynamicAnthropomorphic Robot with Intelligence(DARwIn)-High Performance(HP) at Robotics and MechanismLaboratory(RoMeLa). DARwIn-HP, an miniature-sized humanoid platform, has been developed byself-directed undergraduate students of RoMeLa forrobotics in education. They, as the target consumerof educational robots, contributed to the design andmanufacturing of the DARwIn-HP by sharing theirthoughts on the necessary functionality of an edu-cational humanoid robot. This hands-on experienceallows them to understand the fundamental materi-als of a humanoid robot in theory as well as theusage of mechanical tools in practice. All under-graduates after experiencing the development processalso recognize the importance as well as the interestson learning the subjects in the engineering curricu-lum. As of the final process and post-activity of

This work is supported by the National Science Foundationthrough grant-0958406.

H. Yi (�) · D. W. HongRobotics and Mechanisms Laboratory, University ofCalifornia at Los Angeles, Los Angeles, CA 90095, USAe-mail: yihak@ucla.edu

C. Knabe · T. PesekVirginia Polytechnic Institute and State University,Blacksburg, VA 24060, USA

robot development, encouraging all students to partic-ipate in extracurricular activities provides them witha chance of evaluating their work. There are posi-tive effects to engineering students such as enrichingtheir competitiveness for a range of challenges facingsociety.

Keywords Robotics in education · Humanoidrobot · Robot design · Learning by doing ·Outreach activity

1 Introduction

In recent years, a multi-disciplinary program in engi-neering education has been identified as the signif-icant curriculum to meet the growing needs of asociety [1–3]. This interest has further accelerated anenhancement of multi-disciplinary engineering cur-riculum, capable of magnifying students’ problem-solving abilities for wide-ranging challenges facingsociety [1–3]. These programs that are provided to col-lege students enrich their competitiveness in the areasof science and technology.

Robotics, as an emerging multi-discipline, supportsfuture engineers by helping them to learn a diverseset of knowledge areas through hands-on experience.With the philosophy of “learning by doing”, it devel-ops students’ skills in mechanical engineering, elec-tronic engineering, and computer science, etc., whileteaching students how to integrate these different

42 J Intell Robot Syst (2016) 81:41–49

fields [1, 4–6]. Its all-inclusive nature attracts alot of young students to be interested in studyingboth theoretical and hand-on materials of science,technology, engineering, or mathematics (STEM)[7–9].

Over the last decade, Robotics and MechanismsLaboratory (RoMeLa) has engaged in an effortto specialize in several areas of study such asmechanical design, fabrication, and autonomous robotbehavior. RoMeLa has been devoted to developingminiature-sized educational humanoid robots, calledthe DARwIn(Dynamic Anthropomorphic Robot withIntelligence) series family. Particularly, DARwIn-HP has been developed by self-directed undergrad-uate students of RoMeLa. They, as the target con-sumer of educational robots, have contributed tothe design and fabrication of the DARwIn-HP bysharing their thoughts on the necessary functional-ities of an educational humanoid robot. This expe-rience offers them to understand not only the fun-damental subjects of a engineering background, butalso the knowledge of autonomous humanoid robot.In addition, RoMeLa encourages all students to beinterested in participating in extracurricular activi-ties related to robotics. This provides them with achance of evaluating their works and enjoying theiraccomplishment [9].

This paper will address the experiential learningin the development of a DARwIn-HP at RoMeLa.The rest of this paper is organized as follows:Section 2 explains the robot development in RoMeLa.Section 3 highlights the features of DARwIn-HP.Section 4 presents the RoMeLa’s undergraduateparticipation in the development of DARwIn-HP.Sections 5 and 6 discuss the results of this study andconclusion.

2 Robot Development in RoMeLa

With the philosophy of “Robot Evolution by Intelli-gent Design,” RoMeLa has engaged in an effort to spe-cialize in graduates/undergraduates robotics researchand education. Undergraduate of RoMeLa have expe-rienced the development of a diverse sub-sets ofrobots through hands-on laboratory efforts. It providesthem with opportunities to interact with a variety ofrobots, as displayed in Fig. 1: Robotic Air PoweredHand with Elastic Ligaments; Self-excited Tripedal

Dynamic Experimental Robot; Multi AppendageRobotic System; Hyper-redundant Discrete RoboticArticulated Serpentine; Whole Skin Locomotion; andReactive and Deliberative Motion Control for RoughTerrain Locomotion [9]. Especially, RoMeLa built thefirst full-sized autonomous humanoid platform calledCHARLI (Cognitive Humanoid Autonomous Robotwith Learning Intelligence) in the United States, asseen in Fig. 2 [10].

Particularly, RoMeLa’s experience has beendevoted to developing the DARwIn series family forrobotics education and research as in Fig. 3 [11]. TheDARwIn 0 has similar proportion and mass distri-bution properties to a real human being in order toperform a variety of humanoid research. The secondversion of DARwIn series, called the DARwIn I, wasfocused on mechanical design issues such as eitherthe arrangement of the actuators or maximization ofthe range of motion. Both adding on-board powerfor untethered operation and equipping the DAR-wIn robots with sensors were the main tasks in thedevelopment process of DARwIn II. DARwIn III isconsidered for the bent sheet aluminum to form thethree-dimensional geometry of the links for allowingmany subsystems to be repaired without disassembly.Lastly, DARwIn shows the physical performance thatenable it to run with a flight phase. Every single partof DARwIn IV was optimized for maximum stiffnesswith minimum weight.

Meanwhile, as a significant member of the DAR-wIn generation, DARwIn-Open platform (OP) hasbeen developed in collaboration with many otherresearch groups. It is an affordable platformwith com-putational power, advanced sensor, and high payloadcapacity to enable many exciting robotic activities[12, 13].

3 DARwIn-HP

DARwIn-HP, as seen in Fig. 4, is a further devel-opment of DARwIn IV with a focus on maximizingjoint strength, computing power and manufacturabil-ity. With its high performance, it would serve as aneducational platform, especially in the study of walk-ing or in any area that requires fast and demandingdynamic motions or high strength.

With limb lengths proportional to an adult man,DARwIn-HP stands 0.56 m tall and weights 4.15 kg.

J Intell Robot Syst (2016) 81:41–49 43

Fig. 1 RAPHaEL;STriDER;MARS;HyDRAS;WSL;IMPASS

The 21 degrees of freedom (six in each leg, threein each arm, two in the head, and one in waist)

Fig. 2 CHARLI

powered by commercial servo-actuators (Dynamixel-MX-series) provides the mobility and dexterityto perform a variety of tasks and the mechan-ical ability to run [11]. A cavity in the back-pack is designed to include all of the significantcomponents such as computers, sensors, and elec-tronics. The mechanics of the robot was modi-fied to ease manufacturing and the modularity forrepairs. Its architecture is made of aluminum brackets[3].

The electronic system of DARwIn-HP as displayedin Fig. 5 [12] has a function of providing power dis-tribution, computing platforms, and sensing schemesfor making sense of a salient environment. A Compu-Lab Fit-PC2 computer and a CM-730 sub-controllerallow users to run any operating system and code baseon the computer for low level management. A InertialMeasurement Unit and a Logitech C905 Camera alsoequipped. A 11.3 V lithium polymer battery enablesHP platform to operate for approximately 30 min ofrun time.

The software architecture of DARwIn-HP embod-ies needs to develop capability and function-abilityin an incremental fashion. The software infrastructuresupports an agile development methodology, capa-ble of supporting, reorganization, and testing of newcapability. Low-level interfaces to the hardware areimplemented as C routines callable from Lua. Theseroutines provide access to the camera and other sen-sors, and allow the higher-level routines to modify thejoint angles [13].

44 J Intell Robot Syst (2016) 81:41–49

Fig. 3 DARwIn 0-IV

4 Undergraduate Participation

4.1 Undergraduate Research in RoMeLa

Since its founding in 2004, RoMeLa has maintainedan active team of undergraduate volunteers to sup-port research and lab operations. The jobs performedby them have varied based on the research. In recentyears, due to the popularity and availability of the lab,efforts have been taken to organize the pool of under-graduates into several groups based on their interestsand experience.

Fig. 4 DARwIn-HP

One such subgroup has been the DARwIn Ambas-sadors. These volunteers have been trained by gradu-ate lab members to assemble, maintain, program, andgive demonstrations of the DARwIn series. Recentefforts of the Ambassadors have focused on manufac-ture and assembly of several DARwIn-HP platformsfor distribution. Many of the experienced undergrad-uate enroll in either an undergraduate research posi-tion, or a yearlong RoMeLa-sponsored senior designproject.

4.2 Senior Design Team Lab Infrastructure

RoMeLa typically sponsors one to two senior designprojects annually. Each team is appointed a gradu-ate lab member who defines the scope of the project,relays customer (lab member) needs, and advises

Fig. 5 Electronic architecture of DARwIn-HP

J Intell Robot Syst (2016) 81:41–49 45

Fig. 6 CAD arrangementof two 17.5′′ × 19′′ sheets,consisting of all aluminumparts required to assemble aDARwIn-HP. The rightsheet visualizes the partsfollowing all machiningoperations

design choices. The senior design teams are taskedwith providing the lab with functional prototypes oftheir design following the conclusion of the project.

The benefits for the senior design team and gradu-ate lab members are mutual. The graduate lab mem-bers provide machine training, lab resources, andoversight to the team, while the design team pro-vides brainstorming power, assistance with robot test-ing, and a functional product related to an ongoingresearch. For example, a Bridgeport CNC millingmachine within RoMeLa’s space allows students tolearn new tools’ usage with on-hand experience.Along with the mill a 3D printer was utilized forquickly manufacturing components either expensiveor difficult to manufacture.

4.3 Senior Design Team Projects

Several senior design teams have worked on projectsto further develop DARwIn-HP, which is originallydesigned by graduate members of RoMeLa. First,an undergraduates redesigned the entire platform toaccommodate new actuators. The new DynamixelMX-series features a contactless magnetic encoder,which quadruples the resolution over the previous RX-series. The upgraded processor also handles a tunablePID algorithm, allowing individual adjustment of thespeed and strength of each motor.

Another major undertaking was to refine andstreamline the manufacturing process for DARwIn-HP. The previous manufacturing method involvedmilling of small groups of parts, which proved bothtime-consuming and inefficient. A senior design sub-project consisted of arranging all the aluminum partsonto two large sheets seen in Fig. 6, writing the CNCmachine toolpaths, and finally machining the parts. To

further reduce machining time, custom reusable fix-tures were designed to rapidly perform side operationson multiple parts at once.

They also redesigned the power distribution sys-tem of the robot to accommodate the new MXmotors.DARwIn-HP previously used smaller three batteries:one in the chest and one in each leg. The new powersystem features a single larger capacity battery in thechest, relocating battery mass from the legs closer tothe robot as center of gravity. This capacity increasesdynamic performance, as well as reducing batterycosts and charging time.

While some undergraduate projects pertain toupgrades and redesign, many other projects focuson research to further develop the HP platform.One senior design team created gripper mechanismto replace the original paddle hands. This under-actuation is necessary to allow the use of gripperswithout changing the kinematic configuration or soft-ware associated with attaching additional motors. Thegripper, shown in Fig. 7, features three reconfigurablefingers for grasping a variety of objects.

Fig. 7 Reconfigurable gripper for DARwIn-HP

46 J Intell Robot Syst (2016) 81:41–49

Table 1 Knowledge to be gained from hands-on experiencewith DARwIn-HP stemming from engineering curriculum

Background Subject Content

Mechanics Design CAD

Fabrication CNC machine

Fabrication 3D Printer

Electronics Sensors IMU and camera

Sensors Signal processing

Actuation Dynamixel-motor

Microprocessor Intel Atom Z530

Computing Programming C, C++ languages

Programming Communication

Robotics System Analysis Kinematics

Control PID

5 Results

5.1 Effects to Engineering Curriculum

Undergraduate students participating in the develop-ment of DARwIn-HP have been offered an excellentmultidisciplinary hand-on experience that can sup-plements the theory-oriented lectures [14]. Havingdeveloped a DARwIn-HP, they learned a varietyof practical knowledge regarding humanoid robots:sensors and power management; design, fabrication,and dynamic analysis of a humanoid robot; softwareand system architecture; bipedal locomotion; etc. Inaddition, their participation has strengthened theirunderstanding of the basic engineering background in

practice. Table 1 shows the significant knowledge tothe students that is gained from having hands-on expe-rience with DARwIn-HP stemming from engineeringcurriculum.

Among such engineering subjects, RoMeLa hasmainly focused on mechanical design of robotic sys-tems. Compared to other research groups, RoMeLaenables senior design teams to use all lab resources.This access allows them to be passionate in fur-ther experiencing hand-on activities for developingan autonomous miniature-size educational humanoidrobot. For example, machining components using aTormach 3-axis CNC mill demonstrates the impor-tance of machining processes and tool usage. Alongwith the mill, use of a 3D printer helps them under-stand its ability to quickly manufacture components.The computer backpack of DARwIn-HP, as shown inFig. 8, is designed and 3D printed by them.

Figure 9 shows the response of 65 participatedundergraduates, gained from the development ofDARwIn-HP. It appears that undergraduates whoattended the DARwIn-HP development is likely tofeel strongly the necessity for studying STEM cur-riculum than before. Furthermore, Fig. 10 shows theinterests of undergraduate for all subjects in engi-neering curriculum, necessary for developing theserobots, generally increases. These high numbers indi-cate that project-based learning using robot develop-ment can further accelerates their motivation to beinterested in STEM. Specifically, it appears that 32 %of the respondents is further interested in fabricationprocess relevant to the robot development. There is

Fig. 8 3D printedbackpack of DARwIN-HPa top view b front view

J Intell Robot Syst (2016) 81:41–49 47

Fig. 9 Students’recognition the necessity forstudying STEP after takingpart in robot development

also a significant indication that 25 % of the respon-dents is interested in working on a robot design.

5.2 Outreach Activities

RoMeLa encourages undergraduate volunteers to par-ticipate in outreach and extracurricular activitiesusing DARwIn family series, related to robotics.

Fig. 10 Increased interest of students for each engineeringcurriculum after participating in the DARwIn-HP developement

It provides them with a chance of evaluating theirwork and enjoying their accomplishment. Undergrad-uates in the DARwIn Ambassador program have alsohosted tours for students in K-12, prospective under-graduates and graduates, and adults. At high profileevents, they have demonstrated their efforts to tourgroups and the research community through operatingDARwIns. It motivates them to evaluate their effortsand to receive feedback for improvement of developedor future robots.

The interest in diverse outreach activities, as seenin Fig. 11, has increased consistently over time. Astime passes, the developed DARwIn platforms will bean effective tool to easily interact with young studentsin their educational programs. The increased numberof a diverse activities implies that the outreach activ-ities of RoMeLa’s undergraduates are an opportunityto introduce robotics to students who will be interestedin STEM curriculum.

Further validation of the undergraduate volun-teers’ work has occurred at competitions. RoboCup,the yearly international autonomous robotic soc-cer competition, provides an opportunity for teamsof graduates and undergraduates to work togetherto solve complex robot problems. This competi-tion invokes all participating students to collaboratewith others in the robotics community. They havealso demonstrated DARwIn robots to the public. Itmakes them reconsider what the public thinks ofrobots.

48 J Intell Robot Syst (2016) 81:41–49

Fig. 11 Diverse outreachactivities of RoMeLa

6 Conclusion

For many years, the development of DARwIn-HP atRoMeLa has given undergraduates a hands-on edu-cational experience. The practical experience withproject-based learning helps them understand thefundamental subjects of the engineering curriculum.Both practical and theoletical knowledge are gainedthrough the redesign, manufacture, and assembly ofthe DARwIn-HP. As a post-activity of robot devel-opment, RoMeLa students participate in extracur-ricular activities to evaluate and demonstrate theiraccomplishment.

In conclusion, this study shows that undergraduateswho attended the DARwIn-HP development are likelyto feel strongly the necessity for studying STEM cur-riculum than before. It is noteworthy that they alsorecognize the interest as well as the importance onlearning the subjects in the engineering curriculum.This indication implies the importance of the project-based learning using robot development to furthermotivate college students to be interested in STEM.There are positive effects to engineering students suchas enriching their competitiveness for wide-rangingchallenges facing society.

References

1. Engineering: Issues, Challenges and Opportunities forDevelopment, the 2010 report, UNESCO (2010)

2. Weinberg, R.J., Yu, X.: Robotics in education: Low-costplatforms for teaching integrated systems. IEEE Robot.Autom. Mag. 10(2), 4–6 (2003)

3. Aroca, R.V., Gomes, R.B., Tavares, D.M., Souza, A.A.,Burlamaqui, A.M., Caurin, G.A., Goncalves, L.M.: Increas-ing students’ interest with low-cost CellBots. IEEE Trans.Educ. 56(1), 3–8 (2013)

4. Hong, D.: Collaborative Research: Development of DAR-wIn Humanoid Robots for Research, Education and Out-reach, Annual Report, Virginia Tech, Blacksburg, NSF-0958406 (2013)

5. Manseur, R.: Development of an undergraduate roboticscourse. In: Proceedings of the 27th Annu. Frontiers Educ.Conf., vol. 2, pp. 610–612. Pittsburgh (1997)

6. Mirats Tur, J., Pfeiffer, C.: Mobile robot design in educa-tion. IEEE Robot. Autom. Mag. 13(1), 69–75 (2006)

7. Hernando, M., Galan, R., Navarro, I., Rodriguez-Losada,D.: Ten years of cybertech: the educational benefits ofbullfighting robotics. IEEE Trans. Educ. 54(4), 569–575(2011)

8. Gross, R.J., Oh, P.Y.: A scalable software toolkit forminiature humanoids. In: Proceedings of ARCS, pp. 1–6.Orlando (2010)

9. RoMeLa Webpapge: [Online]. Available: http://www.romela.org/main/Robots (2014)

10. Rawat, K., Massiha, G.: A hands-on laboratory basedapproach to undergraduate robotics education. In: Pro-ceedings of the IEEE ICRA, vol. 2, pp. 1370–1374. NewOrleans (2004)

11. Knabe, C., Hopkins, M., Hong, D.W.: Team CHARLI:RoboCup 2012 Humanoid AdultSize League Winner.RoboCup 2012: Robot Soccer World Cup XVI, pp. 59–64

12. Muecke, M., Hong, D.W.: DARwIn’s evolution: develop-ment of a humanoid robot. In: Proceedings of the IEEEIROS, pp. 2474–2475. San Diego (2007)

13. Ha, I.Y., Tamura, Y., Asama, H., Han, J., Hong, D.W.:Development of open humanoid platform DARwIn-OP.SICE Annual Conference, pp. 2178–2188. Waseda Univer-sity, Tokyo (2011)

14. Yi, S.J., McGill, S.G., Zhang, B.T., Hong, D.W., Lee,D.D.: Active stabilization of a humanoid robot for real-time imitation of a human operator. In: Proceedings of theIEEE International Conference of Humanoid Robots, pp.761–766. Osaka (2011)

J Intell Robot Syst (2016) 81:41–49 49

Hak Yi received his Ph.D. degree in mechanical engineeringfrom Texas A&M University-College Station (2012). He is cur-rently a Post-doc Researcher with the Robotics & MechanismLaboratory at UCLA. His research interests lie in a design andbio-inspired control of a variety of humanoids.

Coleman Knabe is a M.S program student in mechanical engi-neering from Virginia Tech. His research interests currentlylie in the design and implementation of compact linear androtary series-elastic actuators on both a full-sized and small-sizehumanoids.

Taylor Pesek is a mechanical engineering undergraduateresearcher with the Robotics and Mechanism Laboratory at Vir-ginia Tech. His interest lie in the field of both small and fullsized humanoid robots applications to the real world.

Dennis W. Hong is a Professor and the Director of Robotics& Mechanisms Laboratory of the Mechanical EngineeringDepartment at UCLA, Los Angeles. His research focuses onrobot locomotion and manipulation, autonomous vehicles andhumanoid robots, as the inventor of a number of novel robotsand mechanisms. Hong’s awards include the National ScienceFoundation’s CAREER award, the SAE International’s Ralph R.Teetor Educational Award, and the ASME Freudenstein / GMYoung Investigator Award to name a few.