Simulation and Control of a Reconfigurable Robot

This thesis explores the design, development, and control of a bio-inspired, two-legged modular robot capable of executing different locomotions using articulated joint motion. The robot’s structure is intentionally minimal and symmetrical, consisting of two feet, two knees, and two thigh segments connected by a central “bridge.” This configuration was chosen to achieve mechanical simplicity, stability, and balance while offering modular expandability for future enhancements such as sensors, grippers, or camera systems. Each leg can function alternately as a fixed anchor or as the moving limb, enabling locomotion that mimics the peristaltic extension and contraction. The robot was modeled and tested using MATLAB and Simscape, where different types of motion were implemented to evaluate the flexibility, effectiveness, and motion control strategies of the system. Three distinct locomotion modes were developed and analyzed: (1) Leg-Over Movement, where one leg swings over the other in a step-like maneuver, enabling the robot to cross obstacles or reposition on narrow beams; (2) Pivot Rotation, where one leg rotates 180 degrees around the other to reorient the body’s direction without changing location, useful in confined or directional environments; and (3) Worm-Like Crawling, achieved through both imposed joint trajectories (kinematic control) and torque-controlled joint actuation, simulating forward crawling through synchronized extension and anchoring of each leg. Each motion type was validated using visual simulation frames extracted from the Simscape models and organized in sequence. These were supported by trajectory generation techniques using cubic polynomial interpolation to ensure smooth and realistic joint movement. As the system transitions from simulated testing to future physical implementation, appropriate motor technologies were investigated. Real-world joint actuation will require precise, compact, and torque-efficient motors. Hence, two professional-grade motor types were recommended: high-precision servo joint actuators (with harmonic drive and absolute encoders) and closed-loop stepper motors. Potential applications of the robot include inspection and maintenance tasks in hard-to-reach industrial or construction environments, such as pipelines, structural beams, ventilation ducts, and disaster zones. Its small footprint, modular design, and stable crawling mechanics offer a reliable solution where traditional wheeled or multi-legged robots may fail. The project lays a foundation for future extensions involving closed-loop control, terrain adaptability, and integration with sensor-based feedback systems, contributing meaningfully to the field of soft-inspired modular robotics.