Preliminary Design-I: Motor Sizing Calculations Report MAE 162D, Mechanical Product Design –Winter 2013, UCLA R S. Shaefer–MAE162D - UCLA 1 This report is part of your “Preliminary Design Lab-I” assignment. Please use any of the “design report outlines” you were given previously and modify it with your own sections and subsections. This report is due before your next lab session (Week 7). It is recommended that you program or create one or several excel spreadsheets to organize and calculate drive system parameters. The advantage is that as your design evolves and changes, you can modify input parameters and quickly ascertain the impact on performance. Furthermore, it will be helpful to cut-and-paste spreadsheet tables into the Design Reports (please remember to number all equations on the right side). Motor System Calculations: (1)Update and report estimates of your transporter dimensions, total weight, maximum load delivered per run, the location of the Center of Gravity (including the load) and document your final decision for the drive system: FWD, RWD, or AWD. (2)Your transporter design is a work in progress and it might have changed since your previously reported preliminary design calculations. Therefore, update and document the following calculations: a.Report the wheel/plywood coefficient of friction ( Wheel ) for the wheels you have chosen (don’t forget to reference wheel material information). b.Calculated the normal force between rear wheels and the ground (FNR )c.Calculated the normal force between front wheels and the ground (FNF)d.RWD: Calculate the maximum rear wheel tractive force (F TR ) using your estimated drive torque (4.d.ii; next page ) e.FWD: Calculate the maximum front wheel tractive force (F TF ) from drive torque (4.d.ii; next page ) f.Maximum rear wheel tractive force before slip (= Wheel*FNR ) for RWD g.Maximum front wheel tractive force before slip (= Wheel*FNF) for FWD h.Total tractive force of the device (F TR + F TF ) i.Force from gravity acting along the slope (F W ) Compare and see if the machine can climb the slope: Is (2.h) > (2.i) ? j.Minimum required friction coefficients for your drive system (AWD, FWD, RWD) (3)Calculate the required power to move your fully loaded device up the slope (Lecture 2): a.Develop a detailed round-trip move profile for transporting, unloading, and returning back to the loading area. b.Establish reasonable maximum and/or continuous velocities along each segment of the move profile (a typical round trip will take between 1.5 to 3 minutes) c.Determine beta (percent weight distribution between rear and front wheels) along the move profile. d.Calculate required propulsion force (Force Propulsion ) including the inertia force, weight force, friction force, and rolling force– do this for each part of the move profile - provide
