Interdisciplinary Project-Based Learning - A Teaching Study on Modifying a Wheeled Walker

Practice Paper Recommended citation: Wang, Z., Balder, J. C., Upadhyay, A., & Stark, R. (2025). Interdisciplinary Project-Based Learning - A Teaching Study on Modifying a Wheeled Walker. In Kangaslampi, R., Langie, G., Järvinen, H.-M., & Nagy, B. (Eds.), SEFI 53rd Annual Conference. European Society for Engineering Education (SEFI), Tampere, Finland. DOI: 10.5281/zenodo.17631284. This Conference Paper is brought to you for open access by the 53rd Annual Conference of the European Society for Engineering Education (SEFI) at Tampere University in Tampere, Finland. This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License. Interdisciplinary Project-Based Learning - A Teaching Study on Modifying a Wheeled Walker Z. Wang a, 1 , J. Balder b, A. Upadhyay c, R. Stark d a Technische Universität Berlin, Chair of Industrial Information Technology Berlin, Germany, 0009-0009-6822-870X b Technische Universität Berlin, Chair of Industrial Information Technology Berlin, Germany, 0000-0001-9392-3944 c Technische Universität Berlin, Chair of Industrial Information Technology Berlin, Germany, 0009-0006-1817-7914 d Technische Universität Berlin, Chair of Industrial Information Technology Berlin, Germany, 0000-0002-2599-0130 Conference Key Areas: Engineering skills, professional skills, and transversal skills; Building the capacity and strengthening the educational competences of engineering educators Keywords: Interdisciplinary PBL, Collaborative Engineering, Product Development ABSTRACT This paper presents a teaching study of a project-based learning (PBL) course that connects two distinct lecture courses in the context of product development (PD): class A - Applications of Industrial Information Technology (AIIT) and class B - Development and Management of Digital Product Creation Processes (EMP). Both courses include the project of modification of a wheeled walker, with students organised into three interdisciplinary groups. Each group is responsible for developing one out of three technical subsystems, which are automatic height adjustment, medical supervision, and curb negotiation. The groups progress through various phases from ideation and conceptual solutions to virtual prototyping, to physical prototyping, and to final report. By showcasing the critical deliverables produced at each phase of the project, this paper analyses them from an educator's perspective to extract key lessons learned. The insights and recommendations presented herein aim to offer practical guidance for educators who are interested in 1 Corresponding Author Z. Wang [email protected] implement similar courses, thereby contributing to the advancement of pedagogical practices in engineering education. 1 INTRODUCTION In recent years, engineering education has increasingly embraced PBL as a means of deepening students' understanding of theoretical concepts through practical application. Most existing PBL initiatives are focused on a single discipline with project constraints, thereby fostering in-depth subject-specific competence (Kolmos et al., 2024). Only 14 out of 40 projects in the mechanical engineering programme at the TU Berlin are interdisciplinary, involving multiple engineering disciplines (Moses, n.d.). This proportion underscores the scarcity of project courses that integrate diverse engineering disciplines. Such cross-disciplinary PBL courses not only allow students to progress within their own discipline but also equip them with the skills necessary for effective collaboration and communication across different domains. This paper presents a detailed teaching case of a PBL course that combines two distinct lectures, AIIT and EMP, in the context of modifying a wheeled walker to support elderly people in integrating into society. The primary aim of this paper is to explain and analyse the key deliverables generated at each phase of the project. The paper begins by placing the work in the context of PBL and engineering education and introduce the project and its methodology in Chapter 2. Chapter 3 presents the partial results of the project, and the valuable lessons learned, while Chapter 4 offers practical recommendations for educators who wish to implement similar interdisciplinary PBL initiatives. 2 CONTEXT AND PRACTICAL WORK 2.1 Context of Project-Based Learning and Engineering Education PBL courses are essential to engineering education as they combine theoretical knowledge with practical application (Frank et al., 2003) and teach students valuable soft skills such as communication and project management. By working in heterogeneous teams, they learn interdisciplinary thinking, which is essential in modern engineering professions. At the same time, the structured feedback in the design reviews (DRs) strengthens the ability for critical reflection and continuous improvement - a core aspect of both PBL and engineering practice. Overall, the project optimally prepares students for the complexity of real development projects and promotes a practical, research-orientated engineering education. 2.2 Project Description The project is planned every winter semester and open to all master’s students but mainly for those with engineering background, typically in their first year of the programme. It invites students to engage in an industry-oriented challenge. This project encompasses the entire PD cycle, starting from the conceptualization phase and progressing through digital modelling to the realization of a functional prototype. The primary objective is to empower students to execute complex project tasks in a resource-efficient and goal-oriented manner while simulating the dynamics of a startup environment, thereby deepening their understanding of market dynamics, stakeholder engagement, and business model development. 2.3 Methodical Approach The modules were supplemented by specific lectures that conveyed both theoretical and practical content, while accompanying practical seminars provided students with specific methodological and technical skills for the realization of their projects. The examination comprises various deliverables, two DRs as interim assessments and a final presentation of the project results, which simulate a real PD process. The relevance and effectiveness of methodical support such as seminars and deliverables (view table 1 and 2) were researched in previous studies by Balder & Stark, 2024, Hagedorn et al., 2023, Peters et al., 2021 and Mörike et al., 2021. The lecturers are also available for individual counselling. Table 1. Overview of deliverables for AIIT The semester is divided into four phases (view Fig. 1), which are structured by the two DRs and the final presentation. In the first phase (idea and concept creation), the teams develop creative solutions and create concepts for their projects. This includes the development of a project plan with task allocation, the development of a co-operation concept with other teams as well as the creation of a list of requirements and an initial system design. In the second phase (design), the concepts are transformed into concrete designs using CAD modelling and other methods. This involves updating the project plan, creating Business Process Modelling (BPM) processes and a sustainable report. Each team is provided with a budget of 100 Euro, which is used to procure parts necessary for constructing the physical prototypes. The third phase (prototyping and validation) focuses on the realisation and validation of the developed designs. The teams build and test physical prototypes, create a product folder and work on a joint CAD model. In addition, the knowledge gained is documented and checked again for sustainability aspects. This is followed by the fourth phase (reflection), in which the teams analyse their work and summarise it in a final report. Fig. 1. Structure of the semester project The two DRs are strategically integrated into the development process and serve as milestones for presenting progress, receiving constructive feedback and further developing their own approaches. Lead Phase Deliverable AIIT 1 Solution Concepts AIIT 1 Requirement list (template) AIIT 1 System design diagrams AIIT 2 Bill of materials (template) AIIT 2 CAD model of the individual components and assembly model with manufacturing information AIIT 3 Joint physical prototype AIIT 3 Bill of materials of physical prototype (template) AIIT 3 Usage Concept AIIT 3 Joint CAD assembly model 3 RESULTS AND INSIGHTS In winter semester 2024/2025, students are presented with seven system options to explore, each addressing a specific functional requirement. The options curb negotiation (G1), automatic height adjustment (G2), and medical supervision (G3) were subsequently selected by the students, leading to the formation of three project groups, each composed of eight students. Table 2. Overview of deliverables for EMP Although all groups were given identical initial instructions and general objectives, the varied professional backgrounds and skills composition within each team resulted in distinct deliverables. This chapter presents selected examples of these deliverables, highlighting noticeable differences between the groups, particularly in terms of their technical solutions and methodological approaches. From an educational perspective, each phase of the project was analysed by instructors, with corresponding structured feedback to the students provided. 3.1 Phase 1 – Idea and Concept Creation During Phase 1, AIIT students were tasked with developing solution concepts for their respective systems. As depicted in Fig. 2, G1 proposed a solution involving a linear auxiliary wheel mechanism designed to elevate the walker sufficiently to overcome curbs. Their concept was illustrated with simple schematic diagrams but lacking detailed technical explanations, particularly regarding system functionality and implementation specifics. Fig. 3 illustrates that G2 provided a detailed visualisation, clearly communicating the functional implementation process and meticulously annotating the newly integrated components and their roles within the system. The concept of G3 focused on delineating the interactions among different user groups to Lead Phase Deliverable EMP 1 Project plan with task distribution, resource allocation and tool list EMP 1 Collaboration concept EMP 1 Canvas Business Plan (template) EMP 2 Project Plan Update EMP 2 Operationalisation of the ability to collaborate EMP 2 Working in digital transformation EMP 2 BPM EMP 3 Project Plan Update EMP 3 Lessons learned on the teamwork and collaboration EMP 3 Product Map EMP 3 Final Cost Overview EMP 4 Final Report Fig. 2. Concept of G1 Fig. 3. Concept of G2 showcase their overall idea. As depicted in Fig. 4, the system monitors the health of various user cohorts and transmits this information to doctors, caregivers, and hospitals. However, the concept remained predominantly high-level and lacked a detailed focus on the product's tangible aspects. In a softwareoriented approach to medical supervision, students found it challenging to identify a clear entry point for effectively introducing their system's functionality. Consequently, the intuitive hardware elements, which are essential for grounding the concept in reality, were not sufficiently addressed. To enhance clarity and impact, it is recommended that software-centric projects incorporate more illustrative hardware components that can concretely support and communicate the proposed solution. One of the deliverables for EMP students was the project planning. The assignment specifications required that this deliverable include, but not be limited to, components such as the project objective, work packages, competitive analysis, and resource planning. The task not only necessitated the development of general project management elements but also encouraged students to engage in divergent thinking and tailor the plan to their individual project themes. In the absence of concrete guidelines, each group submitted their project plans in different formats. G1 and G2 produced separate files for each component, whereas G3 consolidated all components into a single document. Although this approach granted considerable creative freedom, it also led to uncertainty regarding expectations and increased the complexity of the grading process. While providing explicit guidelines could resolve these issues, it might also constrain students to conventional frameworks, thereby limiting their innovative thinking. In addition, each group incorporated a project mission in their submission. G2 further enhanced their deliverable by including a team skill matrix and cost planning. Notably, with respect to the project objective, only G1 addressed all five aspects of the SMART criteria. These key criteria of the project planning can serve as one of the evaluations. 3.2 Phase 2 – Design In Phase 2, each group was provided with a dedicated folder containing a basic CAD model as a starting point in Fusion 360 by Autodesk. Using this foundational model of a walker and building upon the conceptual ideas developed in Phase 1, students proceeded to create virtual prototypes of their respective subsystems. Fig. 5 illustrates the design of G1, showcasing the controller on the handle and linear actuator. These designs were intended to minimize additional product space. However, deficiencies remain in terms of product feasibility and level of detail. For example, the linear actuator obstructs the drilled aperture, thereby reducing Fig. 4. Solution Concept of G3 Fig. 5. CAD model of G1 Fig. 8. CAD Model of G3 Fig. 7. Stress Simulation of G2 the available space for the clamp installation on the auxiliary wheel. Furthermore, the mounting of the controller lacks the appropriate connecting hardware, and the design also does not include a defined layout for the controller’s wiring. G2 selected the same model of linear actuator as G1 and shared the controller between the two systems. As shown in Fig. 6, their CAD model demonstrates a more comprehensive consideration of key design elements, including the integration of cables, screws, and other necessary components. Additionally, G2 conducted simulations to analyse the deformation and stress distribution of the handle during operation (see Fig. 7). G3 refined and concretised their system design. As illustrated in Fig. 8, they developed a new handle. This virtual model provided a more direct and tangible representation of their concept, with the pulse oximeter and status LED specifically demonstrating a detailed implementation of the electronic components. However, like G1, their virtual prototype did not effectively convey the concept of assembly, leaving certain aspects of the mounting and integration process insufficiently detailed. In summary, AIIT students represents a critical stage in realising the solution ideas. From an educational perspective, it is imperative to balance innovative design with practical implementation. This approach enhances the feasibility of constructing physical prototypes in the subsequent phase while minimising unnecessary rework. To this end, educators should provide explicit guidance on iterative prototype refinement and the effective integration of simulation tools. A critical task for EMP students in this phase was to create a BPM process of the PD. This required students to outline the activities involved in the development process and the corresponding quality gates. To reflect the real-world scenarios, a specific number of activities or gates was not provided. Consequently, students often inquired about the appropriate level of detail but there is no definitive answer, as BPM Fig. 6. CAD Model of G2 does not adhere to a standard level of detail in actual PD. Instead, the emphasis should be on the completeness and logical coherence of the BPM Process. For example, in Fig. 9, G2 ended their process immediately after the construction phase, neglecting the potential need for iterative adjustments in case the construction required modifications. This oversight, which was also observed in other groups, illustrates a common misconception of PD as a linear process rather than one characterised by continuous feedback loops - a seemingly minor activity that nonetheless has significant implications for the success of PD. 3.3 Phase 3 – Prototyping and Validation This phase primarily focuses on the creation of a unified virtual prototype as well as the development of the physical prototype. First, a complete virtual prototype including all subsystems had to be delivered to enable the students to see overlapping and construction errors in their joint prototype. For the physical prototype, G1 prepared a test track to simulate a curb as shown on Fig. 10 (far right) and successfully elevated the walker to a fixed height using a supplementary wheel. G2 installed the linear actuator directly in front of the handle adjustment lever and connected the two components. The Arduino-controlled actuator enables both manual and automatic height adjustments, complemented by LED and audio feedback for enhanced usability. G3 integrated the Raspberry Pi (as shown in Fig. 10, middle-left) with the pulse oximetry, manual emergency button components and step tracking (as depicted in Fig 10, far left), thereby enabling realtime emergency alerts with location via an Internet of Things (IoT) platform (Fig. 10 middle-right). Compared with the virtual prototype, their physical realisation closely mirrored the virtual prototype in both appearance and functionality, as demonstrated by the successful validation of features such as pulse oximetry, a status LED, and an emergency button with integrated position indication (see Fig. 10, right). Overall, each group successfully demonstrated the functionality of their design during the final presentation. Nonetheless, the incomplete order list necessitated additional procurement cycles, which in turn prolonged the installation timeline. Fig. 9. BPM of G2 Fig. 10. Physical Prototype Furthermore, given that these subsystems incorporate electrical components, it is advisable for instructors to be well-versed in electrical safety protocols and to ensure that the use of electrical equipment (e.g., power supplies) occurs under appropriate supervision to maintain a secure working environment. In addition, students require adequate workspace for the mechanical fabrication processes of the prototypes. It is recommended that educators coordinate with workshops in advance or provide dedicated facilities to make activities such as drilling, milling, cutting, and joining (e.g., welding and soldering) effective and safe. 3.4 Phase 4 – Reflection In the fourth phase, students were required to complete the final report within a prescribed component. With no page limit imposed, each group submitted a comprehensive report of 40 to 60 pages that thoroughly reviewed the entire project. G1 placed a greater emphasis on mechanical structure optimisation and practical functional validation, ensuring product safety and durability through systematic design and testing, and addressing technical challenges via effective team collaboration. G2 focused primarily on the innovative implementation technology and user experience optimisation, demonstrating their technical advantages through digital tools and iterative prototyping. Meanwhile, G3 concentrated on IoT integration, underpinned by a comprehensive digital development process and rigorous market regulation analysis. These varied report emphases indicate that different groups allocated distinct amounts of time and interest to specific aspects of the project, revealing the areas they found most engaging. 4 CONCLUSIONS AND IMPLICATIONS Building on the previous studies (e.g., Balder & Stark, 2024; Hagedorn et al., 2023) that have already elaborated the theoretical PBL framework and analyzed students’ feedback in depth, this article presents a teaching study of cross-disciplinary PBL in a PD course, connecting project management and technical engineering. In this use case, three groups of students were responsible for the development of distinct subsystems - curb negotiation, automatic height adjustment, and medical supervision - progressing from ideation through design to the creation of physical prototypes. By showcasing and analysing the deliverables from each of the three phases, this study offers valuable insights and recommendations for similar crossdisciplinary PBL initiatives within engineering education. Organisationally, it is recommended that students from the AIIT programme constitute at least 70% of each group. Ideally, each group should include Information Technology student, Mechanical Engineering students, and Electronics students, with the EMP cohort ideally comprising two to three students with a management specialisation. Notably, discrepancies in expectations between EMP and AIIT students can lead to inter-group conflicts, particularly when their perceptions of the course diverge significantly. Furthermore, providing students with fully equipped and safe workshop environments is crucial for supporting the hands-on aspects of PD. Open tasks, which foster student’s autonomous learning and diverse thinking, may also lead to variations in the depth and format of deliverables, thereby complicating the evaluation process. Consequently, instructors should carefully define and consider general assessment criteria for each task. Finally, to ensure that proper and professional support is provided for all domains, experts for these domains should be available to students as well as teachers, as teachers cannot be considered experts in all required fields.