Introduction
We are a group of 7 engineering students completing a group project in our 4th and final year at the University of Leicester with a budget of £1050. We have chosen to design and manufacture a racing simulator rig that closely matches the driver user experience of the Formula Student car at the university. The rig aims to aid and facilitate the University of Leicester formula student team in gaining experience in controlling a similar automotive system with comparable ergonomics and force feedback.
The correlation data gained from this simulator would prove useful for the formula student team being able to compare lap time data from simulations to real telemetry data, giving opportunities to improve and optimise performance and driveability.
This simulation unit may also be utilised for university open days as a selling point for the engineering school at the university. This would offer exciting and relevant experience at open days that could be a large draw for prospective students as well as a good first impression for formula student recruitment.
At the start of the project, as a group, we created different work packages for the project to split up the work between each member. We made work packages for each key subsystem of the project. This included the chassis, the steering wheel system, the pedal system and the shifter system. 2 members of the group were assigned to each system and the chassis had 1.
The design stage consisted of literature reviews, requirement specifications, concept selections and a final design review against the requirement specifications. The final design can be seen below:
Chassis
The chassis, designed with considerations towards stiffness, modularity, cost and ease of manufacture uses a simple aluminium extrusion box profile design supported by aluminium mounting brackets which are all suspended off the ground by six castor wheels at critical bending positions.
Currently, the Chassis is undergoing manufacture and the material supplied by RS (9 metres of extrusion) will shortly be cut to the appropriate length before assembly.
Steering Wheel System
The original steering system based on the formula student car involved a motor, belt, encoder and gear system. This was edited to allow for stabilisation by incorporating a light gate. Due to the size of this system, it would have been unfeasible to integrate into the chassis, impacting the ergonomics of the driver seat position. Additionally, the complexity of this iteration was cause for concern having multiple points of potential failure.
To solve these issues, a more compact and reliable steering system was designed, this involved servos to supply the force feedback and encoder solutions with a series of gears designed to uprate this for steering wheel sensitivity and motion. This was a much better improvement from the last iteration however, after some discussion, there was concerns as to whether the servos were back-drivable, if they were not, then the force feedback could only be activated in one rotational direction and the wheel would be locked from turning both directions.
Based on this design work and deductive reasoning, an all-in-one steering simulator was chosen from Moza Racing as the final solution. This will cost approximately the same with the exact features that a formula student simulation rig would expect.
Pedal System
The pedal system was closely designed to the pedal system in the formula student car but with the main difference being the formula student pedals were a hydraulic system connecting to the engine whereas our simulator pedals are an electrical and mechanical system connecting to an Arduino.
The pedals are the same length and have the same pedal faces as the formula student car. Through the use of springs inside of a cylindrical metal tube, the pedals can be pushed down and the necessary resistance will be felt. The pedals are connected to a rotary potentiometer which will turn when the pedals are pushed down. The amount that the potentiometer rotates determines the amount of voltage sent to the Arduino board which will determine what happens in the simulation as a result of pushing the pedals. The pedals are made out of mild steel so they are strong and can withstand the forces acting upon them without breaking or bending.
We plan to manufacture the whole system ourselves except for the cylindrical tubes which the technicians at the university workshop will be doing for us. Once manufactured and assembled, the pedals will need to be tested with the Arduino and simulator software to make sure it is calibrated correctly and that they work for the desired output.
Shifter System
The gear shifter is an integral part of the racing simulator with a mechanism designed to replicate the shifting feedback. The main gear stick is connected to a pivot in the middle of the stick so when the user pushes the stick forward, the base of it moves back. Another shaft is connected to the bottom of this stick, where the feedback and signalling are also connected to. The shaft has two plates connected to it separated by a spring, which are also placed between two fixed plates so when pushed, the shaft plate will be stopped by the fixed plate and the spring will provide resistance as it compresses. Releasing the gear stick will return the system to neutral as the spring extends back, pushing the system back to the centre. The pivot will also be connected to a rotary potentiometer which will signal how far forward and backward the shaft has been moved, converting this into up-and-down shifting for the system. It will also detect when the gear stick has been returned to the middle to signal the car is back in neutral.
Software and PC
For our simulator to run we are using the racing simulator game Assetto Corsa as it offers realistic driving experience due to a highly advanced physics engine. As formula students already use Assetto Corsa to compete in the FSUK Sim Racing Series, it seemed the appropriate and easiest software to use. We will add all the characteristics of the formula student car into the game and add in the necessary track that formula student races on. This will make the simulator as realistic as possible and will allow it to be used for the formula student team as aimed.
The university have provided us with 4 monitors and a PC to run to the simulator with. 3 of the monitors will be used as the display screens and another will be used to get real time lap data when the simulation is in operation.
An Arduino board will connect the pedal system, shifter system and steering system to the PC and that will connect to Assetto Corsa and control the inputs made by the user.
RS Student Fund
We would like to thank RS for sponsoring this project and providing us with funding and allowing this project to be possible. We used the money on components for the chassis and it was greatly appreciated. Thank you very much!
Conclusion
We are at the manufacturing stage of the project now and parts are starting to arrive but we are still waiting on a couple of things. We are starting the manufacturing of the chassis, pedals and shifter systems as soon as we can so that we can assemble the simulator as soon as possible allowing for a testing period. The deadline for our simulator to be manufactured is 28th March and we are on track to complete this.
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