• Blog #4 - Recent Work, Pending Work, and Results

    eduard.amador2021 • 11/24/2024 at 04:38 • 0 comments

             In the work period of November 9th to November 23rd, we had the goals to finalize the CAD design of the steering wheel with paddle shifters, selecting the pneumatic components, conducting thermal analysis for insulation on the pneumatics, designing the electrical system, and developing the Arduino program. The steering wheel has gone through design revisions as feedback was obtained from Cougar Racing drivers and FEA models. A Design Matrix was created to compare 4 different versions of the steering wheel (figure 1); the numbers were determined from the drivers themselves and from our input.


                                                                          Figure 1: Decision Matrix

    Versions 1-3 were different wheel designs, though had the same width and handle geometry. After a meeting with the drivers and the Machine Man Interface leads they recommend a wider steering wheel and bigger handles for comfort. This has led to the creation of the 4th version after optimization to achieve a higher safety factor while reducing the overall steering wheel thickness down to 0.25” as version 3 was 0.375” thick. Figure xx shows the difference between version 3 & 4, respectively.
                                                           Figure 2: Steering Wheel Design Changes

    Version 4 has markings on the steering wheel, they represent the placement of the drivers hands when they’re at their most natural position. This was considered in the CAD as it changes the geometry of the paddles.

    The progress for pneumatic components complete was the creation of the pneumatic system components with options for the cylinder, solenoid, pressure regulator, and tubing. In addition, specifications for these components are needed have been selected using a tabulation of scores with comparisons. This portion has been completed through selection of criteria that are important and will ensure an efficient result.

    The pneumatic components progress has tasks that have been completed and are still in progress.

    The completed portion of the pneumatic component tasks is the tabulation of comparison between specifications on the air tank, pneumatic cylinders, and bore size determination. Based on this, a compilation of components from a seller is put together for the pneumatic cylinder, solenoid, pressure regulator for the air tank, pressure regulator to further decrease pressure, hoses, and insulation from the heat was created. The first tabulation was for the bore diameter which will affect the working pressure required to be regulated and the cubic inches per minute of compressed air needed. For the tabulation, there are options set with descriptions to identify what specifications the options were created with, exact values for criteria scored, criteria weights, criteria scores for options, and totals. In this tabulation, a higher score means a worse result, so the lowest number means it's the most efficient for our design. Option 0 was made with the maximum score possible, otherwise the worst score possible. The tabulation of the bore diameter results are below:
                                                    ...
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  • Blog #3 - Work Period Updates

    eduard.amador2021 • 11/10/2024 at 05:24 • 0 comments

    As we are nearing the end of the semester, an update is needed regarding how we used our time from October 27 up until now. Within October 27 and November 9 an iteration of the steering wheel was designed. Inspiration came from an already made steering wheel by FBS Racing Team [Figure 1], their steering wheel has been designed to be as low profile and lightweight as possible. Our design is a heavily modified version that allows space for the attachment of the paddle shifters and a 7 segment display to indicate the gear the car is currently on. The steering wheel is currently being printed to obtain feedback from the Cougar Racing drivers, and to begin to create molds for the grips through the usage of clay and a 3d scanner.

       

                                                          Figure 1: Steering Wheel Sample



    We’ve also researched quick-release kits that have integrated data pins for electronic signals [Figure 3]. 3 data wires are running from an Arduino towards the steering wheel: 2 wires for buttons that are actuated by the paddle shifters and 1 for the gear indicator. 

    As the piston and pneumatic components are selected, they are being derived onto the Cougar Racing master CAD to explore different placements and start designing mounts for the pneumatic components. [Figure 2]



                                                    Figure 2:     Pneumatic Components Near Engine





                                                     Figure 3: Quick Disconnect for Steering Wheel


    To be on track with our capstone and project deadlines, for the work period from November 9th to November 23rd, the team’s plan focuses on finalizing several key design elements following technical analyses. The plan we will work toward is the following:

    1. Finalizing the CAD Design of the Steering Wheel with Paddle Shifters: We will complete the CAD model for the steering wheel with paddles. This design will be inspired by previous designs but refined through FEA (Finite Element Analysis) in COMSOL or SOLIDWORKS to simulate real-world conditions. Based on FEA results, adjustments will be made to optimize safety factors, including modifying the aluminum thickness and selecting an appropriate grade based on the anticipated radial forces. We will also identify stress points and adjust wall thickness and paddle shape accordingly. Our target is to finalize the CAD and complete the FEA review for this assembly within the November 9th to November 23rd timeframe.
    2. Selecting Pneumatic Components: The team will evaluate various pneumatic system options to meet performance and cost requirements. With known constraints, such as the force output, total air tank volume, and maximum tank pressure, we will create 3 to 5 system configurations that include a three-position cylinder, solenoid valve, pressure regulator, and tubing. These configurations will be compared based on working pressure, price, volume, and weight, along with an estimate of operational efficiency for at least 60 shifts per minute. By November 16th, we plan to have a finalized selection based on these criteria in a tabulated point system.
    3. Conducting Thermal Analysis and Insulation Selection: As part of the design process, we will perform a thermal...
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  • Blog #2 - Key Physical Challenges, Constraints, and Analysis

    eduard.amador2021 • 09/26/2024 at 15:35 • 0 comments

    As mentioned previously, the paddle shifter project was developed to improve the competitiveness of the UH FSAE car in the SAE competition. With greater control of the vehicle, the driver can focus better on the track during autocross to improve their lap times instead of constantly shifting with a lever. This improvement was applied by Ferrari's Formula 1 team in 1989 which began the paddle shifter standard in F1 racing [1]. In modern F1 cars, paddle shifters are integrated into the steering wheel, and the paddles themselves, when sold separately, cost more than $700.


                                               Figure 1: $700+ Ferrari F8 Paddles for Paddle Shifter

    For university FSAE teams competing in the annual SAE competition, the cost of paddle shifters is impractical from both a competition and budget perspective. The SAE competition evaluates teams not only on dynamic events such as autocross and acceleration but also on a business presentation, which includes the cost to manufacture the car. While paddle shifters can offer a competitive advantage, they must be implemented affordably without sacrificing performance.

    For the UH FSAE team, the paddle shifters will be paired with a pneumatic system that controls upshifting and downshifting. When the shifter is activated, electronic components will monitor engine RPMs to ensure shifts occur at safe levels. Once the correct RPM is reached, the pneumatic system will apply pressure to pistons that initiate the gear shift, repeating this process for each gear change. Additionally, the paddle shifters must be integrated around pre-existing components and operate while the engine is running, presenting critical physical constraints to consider.

    The entire system, which includes the paddles, electronics, and pneumatic components, must not exceed a maximum weight of 50 lbs to avoid increasing the weight-to-horsepower ratio. The paddles themselves need to withstand a force of 121.1 kg, which represents the grip strength of the 95th percentile of men aged 20-24, as required by the FSAE rulebook. To account for safety, the paddles will be designed to handle 20% more than this force.

    Additionally, the paddles must be positioned at least 24.88 inches from the driver to ensure accessibility for the 5th percentile of women in both upright and reclined driving positions. Paddle shifting time is expected to be 0.4 seconds, based on testing during vehicle operation on track. The system must also allow for easy attachment and detachment within 10 seconds for maintenance or replacement.

    The system's power usage is still to be determined, as it must align with the vehicle's limited power from the stator, and the available space for the paddle shifters on the steering wheel is restricted to 126 cubic inches (9" x 7" x 2"). The total budget for the system is capped at $900, though efforts will be made to reduce costs where possible. In addition, the force required to move the lever and shift the engine's gears remains to be determined, and the system must be designed to withstand engine-convected heat of up to 210°C, ensuring the reliability of both the pneumatic and electronic components in such conditions.

    ConstraintValue                               
    		Comments
    Maximum Weight of the entire system
    		50 lbsThe system includes paddles, electronics, pneumatic components
    Maximum Applied Force Paddles Can Withstand
    		121.1 kg * 1.2
    		The grip strength of the 95th percentile of men aged 20-24 is 121.1 kg, per the FSAE rulebook it must accommodate
    Minimum Force Required to Activate Paddles
    		TBD
    Minimum distance of Paddles from the driver in the upright or reclined...
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  • Blog #1 - Who, What, and Why

    eduard.amador2021 • 09/26/2024 at 15:35 • 0 comments

                                   What is Formula Society of Automotive Engineers? 


    The University of Houston hosts the Cougar Racing team, a student-led racing team abiding the Formula Society of Automotive Engineers’ (FSAE) rules. The nature of a racing team is to continuously be innovating to get ahead of the competition, while “simple is better” has created a solid foundation, improvement of a team requires change. A motorcycle engine is the beating heart of the current Cougar Racing team’s powertrain system, as it is a common trend for those engines to be retro-fitted into FSAE race cars. This approach comes with the benefit that the transmission and engine come built-in together. FSAE teams thus have to design a pedal box that actuates the throttle cable and implement a shifting lever to cycle through the transmission’s gears. Cougar Racing has been using a shifting lever, which requires the driver to take one of their hands off the steering wheel and engage the clutch pedal every time they need to cycle through the gears. This process distracts drivers as they are diverting their focus from a race. If a system can take control of the shifting lever and clutch pedal, this allows the driver to focus on the course which leads to faster lap times.





                      Sample CAD of Paddle Shifters to be placed behind steering wheel



    Our teams approach is to create a paddle shifting system that eliminates the need of a clutch and shifter lever, while keeping the driver’s hands on the steering wheel at all times and reducing the shifting time by 50%. High performance teams have adopted this system into their race cars and became an industry standard (for drivers to focus more on driving). A footprint constrain of 9″ x 7″ x 2″ is considered with the paddle shifters needing to sit behind the steering wheel. The system will be paired with an onboard computer that can read engine data, specifically, the motor rpm, current gear, & wheel speed. As the computer takes in data, it can rapidly change gears with a click on the paddle shifters. A set of pistons would engage the clutch lever and shifting lever which is controlled by the onboard computer through solenoids.

                                 CAD of the Main Assembly of 2024-25 Competition Car   

    With the goal of creating paddle shifters for FSAE, we expect to work around premade hardware which adds difficulty in our design phase. Through in-person data gathering, we will be able to gather dimensions, constraints, and expect the adjustments to made in our early design stages. In the development of the paddle shifters, we will keep in mind how the mechanical components fit onto the pre-existing vehicle, but we must also must consider the environment the components. Considering the parts will be on a functioning car, they must be able to withstand external forces as the car accelerates and decelerates, as well as the heat generated by the engine. If our components are near the engine, an analysis must be done to identify the heat’s effect on our design. Additionally, because the paddle shifters are expected to give a significant competitive advantage, they must have the longevity to be reused in future FSAE cars and abide by the FSAE rule book.