Mars Rover Transmission Shaft

This project develops a shaft-system concept for a Martian drilling application. Instead of treating the shaft as a single sizing exercise, the work breaks the problem into symbolic layout, reaction-force analysis, bending and torsion interpretation, equivalent moment calculations, and final material-informed diameter decisions.

Scope Input and output shaft design for a Martian drill transmission

Analysis Force, shear, bending moment, torsion, and equivalent moment diagrams

Material 42CrMo4 (AISI 4140) for strength and fatigue resistance

Deliverable A mechanically credible transmission story, not only a final number

Project Overview

The work starts with a functional transmission requirement for Martian drilling and then moves into the classical machine-design questions that make the concept useful: where are the loads, how do they combine, and what does that mean for geometry and material choice?

Design Method

I built the logic through free-body thinking first and then into force, shear, moment, and equivalent bending diagrams. That makes the final shaft sizing easier to trust because the intermediate steps remain visible.

Material Choice

The final presentation selects 42CrMo4 (AISI 4140), which fits the need for high strength and fatigue resistance in a system expected to handle dynamic and shock loading.

Key Results

Final shaft diameters were derived from equivalent bending moment analysis combining torsion and bending loads. The output shaft required larger cross-sections at the gear interface due to higher combined loading at that station.

Mechanical Breakdown

From symbolic layout to final shaft sizing.

Hand-drawn symbolic shaft layout — The symbolic sketch captures the transmission architecture before the numerical design work begins.

Input shaft force, shear, moment, and torque diagram set — Reaction forces and internal loads for the input shaft, used to structure the rest of the sizing process.

Equivalent bending moment diagrams for both shafts — Combined bending-plus-torsion reasoning for the input and output shafts.

Theoretical diameter calculation graphic for the transmission shaft — The final diameter view closes the loop between the early diagrams and the final design choice.