Colloquia

Summary

This thesis focuses on improving the maintainability of complex robotic products specifically designed for use in greenhouse environments. While maintainability is a critical factor for uptime and life cycle costs, there is a distinct lack of generalized design literature for products operated in harsh environments such as greenhouses. This environment exposes equipment to high humidity, corrosive cleaning agents, and obstructing green waste. This is adressed by developing the Designing for Maintainability for in Greenhouses (DfMiG) method, which synthesizes general maintainability principles with industry-specific environmental factors.

The DfMiG framework is built upon six key design parameters: modularity, accessibility, usability, resistance, surface runoff, and identifiability. Maintainability can also be measured through metrics such as Mean Time To Repair (MTTR), cleaning time, and diagnosability. A core contribution of the thesis is the creation of a model that accounts for unique greenhouse variables, including corrosive cleaning agents, performance pay incentives that lead to equipment neglect, and the limited technical skills of onsite personnel.

The method is validated through a case study at Batenburg Beenen on a robotic crate-handling system. The initial results of the application of the DfMiG method indicated that a significant reduction in the estimated maintenance time. For example, the total replacement time for a wear part improved from 120 minutes to 75 minutes, representing a 45-minute improvement. Qualitative measurements for failure detection, simplicity, and diagnosability also indicated an improved result for the overall improvement. The evaluation results were that the requirements were broadly phrased rather than strictly following SMART criteria; this non-specific nature was found to spark outside the box thinking and new design ideas. This thesis concludes that the method can successfully provide a fallback for engineers without the need for specialized maintenance training to enhance product longevity and minimize downtime in specialized markets such as greenhouses.