03 / Undergraduate thesis

Webots QuadrupedGait Simulation

An undergraduate control project that turns a quadruped model, kinematics, foot trajectories, and gait timing into a reproducible Webots simulation.

01 Scope & outcome

Scope & outcome

I built a virtual quadruped model in Webots from a physical-prototype reference, derived forward and inverse kinematics, and validated planned gaits in simulation. The hardware work included power-board soldering and motor debugging; the physical robot and complete main-control integration remained unfinished.

02 Control pipeline

Control pipeline

01Model dimensions
02Foot trajectory
03Gait phase
04Inverse kinematics
05Joint angles
06Limit checks
07Webots simulation

03 Foot trajectory decision

Foot trajectory decision

I compared compound-cycloid and eighth-order polynomial foot trajectories with MATLAB plots and Webots runs. The thesis reports the compound-cycloid path produced the more stable simulation behaviour; this is a qualitative simulation finding, not a benchmark claim.

04 Gait implementations

Gait implementations

Walk

A static walk cycle keeps three legs supporting the body while one leg swings.

Trot

Diagonal leg pairs alternate swing and support phases for forward and backward motion.

Lateral motion

The same phase structure is adapted by changing the lateral foot displacement.

Rotation

Leg targets are transformed around the body centre to create in-place turning.

Jump

The four legs are scheduled together with a shared lift trajectory.

05 Simulation evidence

Simulation evidence

**Webots model tree and virtual model**The virtual model follows the dimensions and leg layout documented for the prototype reference.

**Foot-trajectory comparison**The MATLAB-derived plots compare the compound-cycloid and eighth-order polynomial paths used in the design study.

**Lateral-motion simulation**A Webots frame from the left-shift gait implementation.

**Synchronous-jump simulation**A Webots frame from the coordinated jump gait.

06 Motion demonstrations

Motion demonstrations

Trot forwardForward trot simulation with alternating diagonal leg pairs.

In-place rotationIn-place rotation simulation using transformed foot targets.

07 Reproducible simulation settings

Reproducible simulation settings

Trot cycle

0.4 s gait period

Walk cycle

0.8 s gait period

Jump cycle

0.25 s gait period

Jump setup

10 cm lift height and 11 cm step length

08 Limits & next steps

Limits & next steps

The public evidence is simulation evidence; a complete physical quadruped and full main-control integration were not finished in this project.
The controller is kinematics-based and relatively basic, so environmental adaptability remains limited.
MPC, improved drive and structure, and a complete sensing/control circuit are future directions rather than delivered features.
The page does not publish the thesis archive or unreviewed controller code that includes reference implementations.

09 Tools & responsibility

Tools & responsibility

Webots · C · MATLAB · Forward/inverse kinematics · Compound cycloid · Gait planning

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