Design and Control of a High-Dynamic Modular Reconfigurable Legged Robotic System

Summary

Here, we present a protocol to enable beginners to replicate a highly dynamic bipedal robotic system and a modular quadrupedal robot composed of bipeds as the smallest units.

Abstract

Legged robots possess exceptional terrain adaptability, making them an ideal platform for outdoor exploration and cargo transport across complex terrains. The number and configuration of legs play a crucial role in their performance; however, most current designs are monolithic, lacking the flexibility for reconfiguration. The protocol presented in this paper details the design and fabrication of a modular legged robot system with robust walking capabilities and flexible reconfiguration between bipedal and quadrupedal configurations. First, various functional modules are mechanically assembled to complete the construction of the bipedal platform and the assembly of the modular connecting device. Subsequently, using debugging software, we configured the inertial measurement unit and motors, including set controller area network (CAN) identity (ID), baud rate, and other working parameters to ensure they are in the correct working state. Then, we designed a whole-body control strategy and a distributed control framework to ensure stable walking of the bipedal unit and coordinated movement of the assembled structure, respectively. Finally, we validated the system's effectiveness on both bipedal and quadrupedal configurations, enabling the robot to achieve stable outdoor walking.

Introduction

Legged robots, utilizing a discrete support mechanism, exhibit superior terrain adaptability and agility^1,2. In recent years, legged robots have been deployed in scenarios such as rescue and search operations, achieving favorable results^3,4,5. Legged robots of various configurations offer distinct advantages for different tasks. Bipedal robots, with their simple design, can navigate narrow spaces but have limited load capacity. Quadrupedal robots are more complex but can carry heavier loads and move faster. Robots wit....

Protocol

1. Construction of the machine

1. Assemble the linkage, housing, and calf using screws and fasteners, and then connect the assembled linkage to the motor output shaft's key pin using fasteners (Figure 1).
   NOTE: The leg, which comprises the linkage, motor, bearings, etc., is the primary component of the robot responsible for its motion.
2. Initialize the motors using the software provided by the motor manufacturer. This includes the calibration of Hall sensors and encoders.
3. Fasten the two assembled legs with carbon fiber plates and appropriate connectors to create a bipedal structure, as illu....

Results

To validate the effectiveness of the proposed system, we conducted outdoor walking tests on multiple terrains. Initially, a single bipedal module was selected as the test subject, and motion tests were conducted on both artificial grass and a synthetic track. As shown in Figure 8, the robot demonstrated stable locomotion on both terrains. The posture and joint torque data of the robot during locomotion are shown in Figure 9. The amplitude of the robot's roll and.......

Discussion

The modular legged robot proposed in this paper offers a new perspective on legged robot design, where reconfiguration and coordinated movement are achieved through the combination of multiple distributed leg modules. This approach presented in this paper has been experimentally validated, confirming its capability for configuration reconfiguration and coordinated movement. Sections 1, 2, 4, and 5 in this protocol represent the critical stages in the implementation of this design, covering the development of both the rob.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Battery	YOBOTICS	https://yobotics.cn/
Electromagnet	Kaka Electric	H25
Electronic component	JLC	https://yobotics.cn/	Including commonly used components such as resistors, capacitors, inductors, etc
IMU	LORD	3DM-GX5-45
Motor	YOBOTICS	https://yobotics.cn/
Power Management Module	JLC	P1
Remote control	Ledi	https://yobotics.cn/
Router	linwlan	GX30
SPI	YOBOTICS	https://yobotics.cn/
Structural parts	3D printing service	N/A	M1-1, M1-2, M1-3, M1-4, M1-5, M1-6, U1, U2, LX1, LX2,LX3, LX4