Tensegrity Drone Landing Legs for Shock Absorption

ISEF Category: Engineering Technology: Statics and Dynamics

Subcategory: Other  ·  Difficulty: Advanced  ·  Setup: University Lab  ·  Time: Full Year

The Hook

A drone can survive a bad landing if its legs act like a springy cage. Tensegrity structures do this with cables in tension and struts in compression. That same idea can turn a hard impact into a softer stop. You can test which geometry protects a drone best.

What Is It?

A tensegrity landing leg uses a network of elastic cords and rigid parts to spread out impact forces. Instead of letting the hit go straight into the drone frame, the structure bends, stretches, and rebounds. Think of it like a basketball shoe sole, but built from strings and struts.

The key idea is load path. When the leg touches down, force does not travel through one stiff line. It splits across many members, so the peak acceleration can drop. In your project, you would compare different shapes, cord tensions, and strut lengths to see which design reduces the landing shock the most.

MuJoCo gives you a way to test designs in simulation before you print parts. Then an IMU, or inertial measurement unit, gives you real acceleration data during drop tests. That lets you compare model predictions with physical results.

Why This Is a Good Topic

This topic works well because you can change one design variable at a time and measure the result with clear numbers. You can test geometry, cord tension, mass, or leg angle, then compare peak acceleration, rebound, and stability. The project connects to drone safety, robotics, and lightweight impact protection. You can also learn modeling, CAD, 3D printing, sensor data analysis, and basic structural mechanics.

Research Questions

• How does the tensegrity leg geometry affect peak landing acceleration?
• What is the effect of elastic cord stiffness on rebound height and impact damping?
• Does increasing strut angle reduce peak acceleration during a drop test?
• To what extent does landing mass change the shock absorption performance of the leg?
• Which tensegrity configuration gives the best balance between low peak acceleration and fast recovery?
• How does the MuJoCo model prediction compare with IMU measurements from physical drop tests?

Basic Materials

• Small drone frame or test mass with similar weight.
• Elastic cord or shock cord in several stiffnesses.
• 3D printer or access to one.
• Basic CAD software for part design.
• Digital kitchen scale with 0.1 g accuracy.
• Smartphone or microcontroller-based IMU logger.
• Mounting tape, zip ties, and small fasteners.
• Measuring tape or ruler.
• Drop test platform or safe release setup.
• Protective eye wear.

Advanced Materials

• Small quadrotor test platform or instrumented drone shell.
• University or makerspace 3D printer with stronger filament options.
• Selection of elastic cords with measured force-extension curves.
• Calibrated IMU module with data logging.
• High-speed camera for impact motion analysis.
• Force plate or load cell for ground reaction data.
• Materials testing tools for cord characterization.
• Computer with MuJoCo and CAD software.
• Fixture for repeatable release height and landing angle.
• Spare struts, joints, and replacement cords for design iteration.

Software & Tools

• MuJoCo: Simulates the landing leg under different geometries and material settings.
• Fusion 360: Helps you model the tensegrity parts and prepare them for printing.
• Python: Lets you clean IMU data, plot acceleration, and compare design versions.
• ImageJ: Measures rebound motion from video frames if you record the drop test.
• Excel: Organizes test runs and calculates summary statistics.

Experiment Steps

1. Define the exact landing problem you want to solve, such as lowering peak acceleration or reducing bounce.
2. Choose one design variable to sweep first, such as strut length, cord tension, or leg angle.
3. Build a simple simulation model so you can screen designs before printing hardware.
4. Plan a physical prototype series that keeps mass, release height, and landing surface consistent.
5. Decide how you will log and compare IMU signals, rebound, and any visible failure modes.
6. Set up a control design, then test whether your tensegrity leg beats it under the same conditions.

Common Pitfalls

• Letting the drone mass change between trials, which confounds the effect of the landing leg design.
• Treating the cords as identical without measuring stiffness, which makes simulation and hardware disagree.
• Using a drop setup that changes landing angle, which adds side loads that hide the real shock response.
• Mounting the IMU loosely, which creates sensor noise that looks like impact spikes.
• Comparing designs only by one test run, which makes random bounce or slip look like a true performance difference.

What Makes This Competitive

A strong version of this project goes beyond a simple print-and-drop test. You would build a real comparison between simulation and hardware, then explain where the model matches, and where it fails. You could also test a design space, not just one prototype, and use statistics to compare peak acceleration, energy return, and landing stability. That kind of analysis shows real engineering judgment.

Project Variations

• Test the same tensegrity leg with different drone masses to see how payload changes shock absorption.
• Compare elastic cord materials to find which one gives the best damping without making the leg too stiff.
• Analyze off-axis landings to learn how the design handles tilted impacts, not just straight drops.

Learn More

• NASA Technical Reports Server: Search for drone landing gear, impact attenuation, and structural dynamics reports.
• MIT OpenCourseWare: Look for mechanics, dynamics, and robotics courses that cover modeling and vibration basics.
• NOAA National Centers for Environmental Information: Use archived environmental data if you want to test landings on different surface conditions in a controlled way.
• PubMed: Search review articles on impact biomechanics and energy dissipation for ideas on shock absorption metrics.
• Journal of Sound and Vibration: Read papers on vibration, damping, and impact response through your school library or abstract search.