WorldAutoSteel advances steel’s advantages in the automotive and future mobility industries. We’re committed to engaging with future engineers at post-secondary education organizations around the globe. Our most recent engineering project, Steel E-Motive, was created to help the industry meet the challenges of future mobility and Level-5 autonomous vehicles and eventually reach net zero emissions targets.
We engaged Ricardo plc to collaborate with our technical directors to develop a Level 5 Autonomous Vehicle for the Steel E-Motive project. The project uncovered a few challenges that were solved by student engineering teams through Senior Capstone Projects. Here we summarize the Side Door and Door Hinges project, created at Michigan Technological University by the engineering students and faculty members listed herein.
Michigan Tech University – Senior Capstone Project #2: Adaptation of SEM2 from People Mover to Commercial Delivery Vehicle
MTU Senior Capstone Team: Kyle Davis, Nick Palatka, Evan Larson, Logan Pietila, Blake Pietila, Tej Bergin
Introduction and Background
This Senior Capstone Design Team was sponsored by WorldAutoSteel and Ricardo Engineering (UK engineering and consultancy firm) to develop a solution for expanding the serviceability within a 24-hour period for Steel E-Motive 2 (SEM2), their extra-urban electric autonomous vehicle concept.
The SEM2 vehicle is a stretched 6-passenger commuter targeting longer journeys with expanded occupancy or additional luggage capacity. In non-commuting hours, the Mobility Fleet Operator would like to continue revenue generation by quickly adapting the vehicle for commercial delivery services. Currently, occupant packaging contrasts with the storage requirements of a package delivery vehicle; thus, the SEM2 vehicles can only be utilized to either transport people or goods. Our project aims to develop interior seating that enables quick removal and adaptation to an optimal delivery van.
Project Details and Results
From the requirements outlined by WorldAutoSteel, the team focused further research on interior vehicle and seat design. Modern delivery methods, delivery vehicle layout, passenger vehicle seat safety requirements, and seat folding or locking mechanisms were sub-categories of research that hold value within the project’s scope. The main takeaways from our research include different pin and slot mechanisms that are incorporated into a preliminary design for a quick-release system. We also benchmarked a vertical folding seat based on International Harvester designs, and we have modified these for application to the SEM2 vehicle’s specific needs.
The quick-release system will benefit MSP technicians responsible for performing the conversion of multiple SEM2 vehicles in its fleet at their depot during off-commuting hours. In under 30 minutes, the fleet operators (MSP) must be able to convert the vehicle from a vehicle stressing passenger comfort to an autonomous delivery van and vice versa, using common tools and techniques while meeting all necessary safety standards and regulations. The fleet operators that provide the robotaxi service are not expected to see any major disruption in ride services; however, they may observe improved utilization and profitability if they use the vehicles for package delivery.
Our current engineering requirements include:
- Maximum total payload of 675 kg (6 passengers and 6 seats)
- Individual seat weight of 30kg (6 seats)
- Total volumetric storage space requirement of 1 cubic meter
- Total seating width equal to or less than 1220 mm
- Changeover time less than 30 minutes and
- Minimal number of changeover movements (Fewer than 50 for the complete conversion from passenger to cargo transportation)
Concept Solutions
A graphical rendering of our selected system-level autonomous vehicle concept is provided in Figure 1. This design showcases two pairs of T-shaped rails placed in the fore-aft direction of the vehicle. These T-Rails are compatible with a slider system connecting to each seat leg’s bottom.
A sliced view of the rails and slider system are seen in Figure 2. On each slider, in the port-starboard direction, a circular slot approximately 20 mm in diameter (dependent on pin material and size) is cut-out to allow for the insertion of a spring-loaded steel pin. This pin engages both the slider and an equivalent slot cut into the rail, to allow the seat to be locked into a specified position along the rail (Figure 3). The rails run the full length of the vehicle’s interior, allowing 3 seating modules to be placed and locked into a position. Inserting and removing the slider on the rails will be possible through narrow sections where the slider can be vertically lifted or placed on the rail system.
In order to “drop the seats” onto the rails without manual lifting, the team has designed an accompanying “pallet jack accessory” that will be able to hold, transport, and lower the seating modules onto the rail system through the use of an industry-standard pallet jack with a lifting range of 6 inches. The pallet jack accessory can be seen in Figure 1, item C.
Figure 1 – System level concept – rapid adaptation of SEM2 to autonomous delivery services
The slider mechanism, seen in Figure 2 below, will house a ball roller bearing that allows for the translational motion along the rail to slide the seats into position.
Figure 2 – Slider mechanism in Steel E-T-rail system
The roller bearing bolts into the slider mechanism allowing for fast and easy replacement. The T-Rails are then bolted to the structural members of the vehicle, where engineers from WorldAutoSteel have confidence the design can withstand any and all static and dynamic loading scenarios. The rails will feature a narrow section near the center, allowing the seating module to be removed. This narrow section is tapered to allow the slider to be “homed” and slid into its final, fixed position.
The arms of the pallet jack system reach out to allow a set of seats to be placed on the rail at one time. The pallet jack will drive through the open slots on the ground, lift the seats to the vehicle, align itself using markings on the vehicle, and drop the seats into the rails, where they can then be manually moved to their correct position. The system is designed to remove and insert these seats as fast as possible while exerting minimum effort that might stress the MSP technician. With ease of use and safety being the critical elements of every project, we’ve removed manual lifting from the equation and ensured a factor of safety of 2 is kept for all required crash loads under our current design.
Many integral components are COTS parts and can be bought in bulk to use for mass production as well as reserved parts, helping maintain low cost of ownership for the MSP. The components that are not COTS items, such as the rails and sliders, can be manufactured using high-volume, low-cost fabrication techniques such as stamping. Assembly of the system will be just as easy as all components are connected together using industry-standard fastening and welding techniques.
Conclusions
Validation – To confirm the ease of changeover and our objectives, a simulation was conducted to estimate the time and difficulty of changing from delivery service to people transporter. In a warehouse setting, a location was established as the “vehicle maintenance spot.” We developed a “seat module storage area” approximately 30 meters away. In this simulation, the following steps were conducted:
- A pallet jack was pre-staged near the vehicle, signaling the beginning of the conversion and timer
- A technician walked 30 m to the seating storage area and picked up the seats via accessory
- They carried seats back to the vehicle, aligned the pallet jack with the door, lowered seats onto the rail system, and removed the pallet jack accessory from the vehicle
- They slid the seats into the correct position and inserted the locking pin into its slot
This simulation was repeated twice to replicate the insertion of all six seats. To remove the seats, the steps would be reversed. After five runs of this simulation, ensuring adequate time to perform each simulated step, the average time to complete the simulation was 5 minutes 17 seconds with a total of 24 required movements.
These values were well within the 30-minute and 50-movement objectives. For further validation, we’ll repeat these simulations in the opposite direction, ie, removing the seats to transform into the delivery van. Finally, in Phase 2 of this project, we’ll continue to evaluate seat frame/track componentry to ensure robustness and durability in the proposed solutions.
More Info About Steel E-Motive
We are grateful to our student teams, their supportive leaders, and the universities providing automotive engineering education to our future industry leaders. Their contributions to Steel EMotive have been invaluable.
Interested in learning more about Steel E-Motive and the infinite tunability of steel for Future Mobility? Download the full engineering report here: Steel E-Motive Engineering Report