Design and Development of a Low-cost ESP32-based Quadruped Spider Robot

Abstract

Legged robotic systems have garnered significant attention for their ability to operate in unstructured and uneven environments, where traditional wheeled robots face mobility limitations. Inspired by biological locomotion, quadruped robots offer enhanced stability and adaptability through multiple points of ground contact. This study presents the design, development, and experimental evaluation of a low-cost quadruped spider robot capable of stable and coordinated legged locomotion using an embedded control platform. The proposed system is based on an ESP32 microcontroller, which performs real-time control and wireless communication. Each leg is actuated by three servo motors corresponding to the hip, knee, and foot joints, resulting in a twelve-degree-of-freedom configuration that enables smooth and synchronized motion. Bluetooth communication is employed to allow real-time command input from a mobile device, ensuring flexible and intuitive control. A diagonal alternating gait algorithm is implemented to achieve stable locomotion by dividing the legs into support and swing phases, thereby maintaining balanced weight distribution during movement. Precise servo actuation is achieved using a dedicated PWM servo driver module, which reduces computational overhead on the microcontroller. The robot structure is fabricated using lightweight materials to minimize power consumption and mechanical stress. Experimental evaluation under controlled conditions demonstrates stable walking behaviour, reliable wireless response, and smooth joint coordination. While minor limitations in load capacity and locomotion speed were observed due to actuator constraints, the overall performance validates the feasibility of the proposed system. The developed platform serves as an effective testbed for embedded gait control and provides a foundation for future enhancements such as autonomous navigation and adaptive locomotion.