Dataset: Comparison of Propulsion Costs and Vibrations Across Carbon Fiber and Aluminum Rigid Manual Wheelchairs Jacob Misch 1,2 Taylor Allen 1,2 Alicia Suarez 1,2 Stephen Sprigle 1,2,3 1 Rehabilitation Engineering and Applied Research Lab, Georgia Institute of Technology, Atlanta, Georgia, United States of America 2 School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America 3 School of Industrial Design, Georgia Institute of Technology, Atlanta, Georgia, United States of America Email contact: rearlab@gatech.edu The contents of this dataset and corresponding journal article were developed under a grant from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR grant number 90IFRE0036-01-02). NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents of this dataset and corresponding journal article do not necessarily represent the policy of NIDILRR, ACL, or HHS, and you should not assume endorsement by the Federal Government.This work was also supported in part by internal funding from the Rehabilitation Engineering and Applied Research (REAR) Lab. This data was used in the manuscript submitted to ASME Open Journal of Engineering, with manuscript number: AOJE-23-1073 Title: Comparison of Propulsion Costs and Vibrations Across Carbon Fiber and Aluminum Rigid Manual Wheelchairs Authors: Jacob Misch, Taylor Allen, Alicia Suarez, Stephen Sprigle DOI: The methods of data collection for the main outcome metric (propulsion cost) are summarized in the journal article, with references to more detailed articles. The data analysis methods are described in depth within the journal article associated with this dataset, which is open access. Data was collected between May 2022 to February 2023. This workbook includes a reference worksheet with accelerometer placement and two worksheets with data: "Data" - Data related to the main outcome metrics (propulsion cost, vertical vibrations, transmissibility ratios) of each tested wheelchair. More detailed descriptors of the data and column headers can be found in the worksheet. "Statistical Analysis Results" - Data related to the performance comparisons between the aluminum and carbon fiber frames. Ratios and corresponding 95% confidence intervals are reported. An example plot is shown to illustrate the 'Superior', 'Inferior', and 'Comparable' performance classifications. One plot combining the three main comparisons is also included. "Data" columns: MATERIAL - The main material used for the manual wheelchair frame (aluminum or carbon fiber). CONFIGURATION - The identifier given to the wheelchair configuration to represent the make and model of the wheelchair frame. Four wheelchairs were used in this study: Apex A (Aluminum) by Motion Composites; Apex C (Carbon Fiber) by Motion Composites; Rogue (Aluminum) by Ki Mobility; and Quickie Nitrum (Aluminum) by Sunrise Medical. SURFACE - The surface on which the tests are conducted (Brick, Grates, Sidewalk, and Tile). SEAT - Root-mean-square (r.m.s.) value of the vertical vibrations (in m/s^2) measured under the robotic AMPS tester. The accelerometer was mounted to the top of the foam seat cushion. AXLE 1 - Root-mean-square (r.m.s.) value of the vertical vibrations (in m/s^2) measured by the first axle-mounted accelerometer. AXLE 2 - Root-mean-square (r.m.s.) value of the vertical vibrations (in m/s^2) measured by the second axle-mounted accelerometer. AVE AXLE - Averaged value from the two vertical axle r.m.s. vibration values. TRANSMISSIBILITY - Calculated by dividing the SEAT by the AVE AXLE vibration values. Represents the ratio (m/s^2 / m/s^2) of vibrations transmitted through the frame to the top of the seat cushion. PROPULSION COST - The propulsion cost (energy per distance traveled) for the straight maneuver, reported in joules per meter (J/m). "Statistical Analysis Results" columns: COMPARISON - The metric of comparison that is being made using the ratio of interest in the "RATIO" column. For this study, carbon fiber and aluminum frames were compared using propulsion cost (J/m), vertical vibrations at the seat (m/s^2), and transmissibility ratios (m/s^2 / m/s^2). RATIO - The identifier given to the comparison of interest. For this study, each comparison used the values from the COMPARISON column (e.g., propulsion cost values) for the carbon fiber frame and compared them to the values for all three aluminum frames. A point estimate value of 1.0000 would indicate that carbon fiber and aluminum have identical average propulsion costs. A point estimate below 1.0000 indicates the group in the numerator (Carbon Fiber, in this example) has lower propulsion costs, or superior performance, than the group in the denominator (Aluminum). SURFACE - The surface on which the tests are conducted (Linoleum Tile or Decorative Brick). Tile was used exclusively for propulsion costs and the decorative brick was used for vibratory comparisons. POINT_ESTIMATE - The point estimate of the ratio (test mean / reference mean), calculated as indicated in the "RATIO" column. LOWER_BOUND - The lower extent of the 95% confidence interval built around the point estimate. UPPER_BOUND - The upper extent of the 95% confidence interval built around the point estimate. CLASSIFICATION - One of three outcomes (superior, inferior, comparable) of the Two One-Sided Tests (TOSTs). The extents of each 95% confidence interval are compared against equivalence limits (±5% for propulsion cost, or 0.95 to 1.05, and ±6% for vibrations and transmissibility ratios). Confidence intervals that are completely below the limits are considered 'Superior' as the test configuration (group in the numerator) experienced lower values than the reference configuration (group in the denominator). Lower propulsion costs, vibrations, and transmissibility ratios are all considered 'better'. Similarly, confidence intervals completely above 1.05 are considered 'Inferior' as the test configuration experienced higher values, reflecting worse or inferior performance. Confidence intervals that cross one or both limits, or that reside completely within the limits, are considered 'Comparable' as the test and reference groups both exhibited similar performances. Methods: The objective of this study was to measure the propulsion efficiency and vibratory characteristics of aluminum and carbon fiber frames for manual wheelchairs equipped with standardized components (drive wheels, tires, and casters) and loading conditions (occupant mass, weight distribution). A wheelchair-propelling robot [1] was used to propel the wheelchair with standardized propulsion characteristics over smooth linoleum tile and decorative brick surfaces. Mechanical energy expenditure and travel distance were measured with sensors integrated within the robotic propulsion device. These methods are similar to those used to capture propulsion efficiency as described in [2,3] and vibration exposure as described in [2,4]. Three aluminum and one carbon fiber ultra-lightweight manual wheelchair frames were used in this study (Apex A by Motion Composites; Rogue by Ki Mobility; Quickie Nitrum by Sunrise Medical; Apex C by Motion Composites). Each configuration was equipped with 24x1-3/8" tires inflated to 75 psi on metal-spoked wheels, with solid 5x1" urethane casters and rigid aluminum caster forks. The Anatomical Model Propulsion System (AMPS), the wheelchair-propelling robot, propelled the wheelchair (in each configuration) in a straight line approximately 10 meters forward, at a speed of 1 meter per second, across two common surfaces. Ten of these over-ground trials were run per surface for each configuration. Propulsion costs were calculated by summing the energy supplied by the AMPS to the wheelchair, and dividing that value by the total distance traveled during the trial. Vibrations were recorded with triaxial accelerometers mounted to the seat cushion and the axle of each wheelchair. Root-mean-square values of the vertical vibrations at the seat were reported. Vibration transmissibility was calculated by comparing the seat vibrations to the average axle vibrations. These three primary outcome metrics were used to compare the propulsion efficiencies and vibratory characteristics between the two frame materials. (More detailed methods can be found in the associated article in ASME Open Journal of Engineering.) References in Methods: [1] Liles, H.; Huang, M.; Caspall, J.; & Sprigle, S. (2014). "Design of a Robotic System to Measure Propulsion Work of Over-Ground Wheelchair Maneuvers". IEEE Trans Neural Sys Rehabil Eng, Vol. 23, no.6, pp. 983-991. doi: 10.1109/TNSRE.2014.2371339 [2] Misch, J.; & Sprigle, S. (2022). "Estimating whole-body vibration limits of manual wheelchair mobility over common surfaces". Rehabil Assist Technol Eng. doi: 10.1177/20556683221092322. [3] Misch, J.; & Sprigle, S. (2021) "Effects of wheels and tires on high-strength lightweight wheelchair propulsion cost using a robotic wheelchair tester". Disabil Rehabil: Assist Technol. doi: 10.1080/17483107.2021.2012274. [4] Misch, J.; Liu, Y.; & Sprigle, S. (2022). "Effect of Wheels, Casters and Forks on Vibration Attenuation and Propulsion Cost of Manual Wheelchairs". IEEE Trans Neural Sys Rehabil Eng, Vol. 30, pp. 2661-2670. doi: 10.1109/TNSRE.2022.3205507