individual
What campus are you from?
Daytona Beach
Authors' Class Standing
Rithika Nagarajan, Senior
Lead Presenter's Name
Rithika Nagarajan
Faculty Mentor Name
David Canales Garcia
Abstract
Small lunar payloads must land safely on sloped, uncertain terrain but often cannot afford the mass and complexity of fully active landing gear; conversely, rigid passive legs offer limited stability margin. We evaluate a low-complexity alternative: passive–adaptive legs that retain a passive spring–damper architecture while scheduling per-leg stiffness and damping from only the local slope and vertical touchdown speed. A minimal SE(3) MATLAB simulator models a four-leg lander on plane terrain (0–30◦ about +y) with lunar gravity (1.62 m s−2), viscous tangential friction capped by a Coulomb limit (𝜇 = 0.6), and ode45 integration (time step ≈ 2 ms, horizon 6 s). Metrics include center-of-pressure (COP) margin relative to the support polygon, peak total normal force Í 𝐹𝑛, lateral attitude overshoot, slip distance, and fraction of time at the friction cap. On a 10◦ slope the adaptive legs reach the high-margin COP plateau (∼ 0.60 m) about 0.3 s earlier than fixed and show lower impact spikes. Across slopes, minimum COP margin declines with angle for both designs; peak Í 𝐹𝑛 follows 𝑚𝑔 cos 𝜃 and is consistently smaller with adaptive damping; attitude overshoot peaks near 15◦ for the fixed case (∼ 2.8◦) and is reduced or shifted higher with adaptation. In robustness tests at 10◦ with touchdown speeds 𝑣𝑥 ∈ {−0.5, 0, 0.5} m s−1, adaptive legs reduce slip distance and friction-cap dwell by roughly 15–25% while maintaining similar final COP margin. A sensor-light, algebraic gain schedule thus improves touchdown transients and post-touch stability without the mass or complexity of fully active legs. Future work will add compliant footpads and regolith (Bekker) models, perform uncertainty sweeps and validate with drop tests.
Did this research project receive funding support from the Office of Undergraduate Research.
No
Adaptive Lunar Landing Legs: Minimal SE(3) Modeling and Evidence of Robustness on Slopes
Small lunar payloads must land safely on sloped, uncertain terrain but often cannot afford the mass and complexity of fully active landing gear; conversely, rigid passive legs offer limited stability margin. We evaluate a low-complexity alternative: passive–adaptive legs that retain a passive spring–damper architecture while scheduling per-leg stiffness and damping from only the local slope and vertical touchdown speed. A minimal SE(3) MATLAB simulator models a four-leg lander on plane terrain (0–30◦ about +y) with lunar gravity (1.62 m s−2), viscous tangential friction capped by a Coulomb limit (𝜇 = 0.6), and ode45 integration (time step ≈ 2 ms, horizon 6 s). Metrics include center-of-pressure (COP) margin relative to the support polygon, peak total normal force Í 𝐹𝑛, lateral attitude overshoot, slip distance, and fraction of time at the friction cap. On a 10◦ slope the adaptive legs reach the high-margin COP plateau (∼ 0.60 m) about 0.3 s earlier than fixed and show lower impact spikes. Across slopes, minimum COP margin declines with angle for both designs; peak Í 𝐹𝑛 follows 𝑚𝑔 cos 𝜃 and is consistently smaller with adaptive damping; attitude overshoot peaks near 15◦ for the fixed case (∼ 2.8◦) and is reduced or shifted higher with adaptation. In robustness tests at 10◦ with touchdown speeds 𝑣𝑥 ∈ {−0.5, 0, 0.5} m s−1, adaptive legs reduce slip distance and friction-cap dwell by roughly 15–25% while maintaining similar final COP margin. A sensor-light, algebraic gain schedule thus improves touchdown transients and post-touch stability without the mass or complexity of fully active legs. Future work will add compliant footpads and regolith (Bekker) models, perform uncertainty sweeps and validate with drop tests.