Study On The Distributed Hierarchical Control System Of A Multilegged Walking Robot

Modular reconfigurable multilegged walking robot consists of exchangeable modules that have the similar geometric features and functions, and the function of the module defines its position in the robot. Due to its capability to change its configuration according to the external environment and the requirement of tasks, good adaptability to complex terrain and high flexibility, Modular reconfigurable multilegged walking robots have become a research hotspot. This paper focuses on the robot's control system of a modular reconfigurable multi-legged walking robot. The work is as follows:According to the mechanism characteristics of the modular reconfigurable walking robot, a distributed hierarchical control system is presented. The control system composed of a PC-based computer, a body-level controller and several base-level controllers (the number is decided by the configuration of the robot). The PC-based computer is responsible for the motion planning, trajectory generation, gait generation, and computation of kinematics, etc. The function of the body-level controller is communication with PC and generating the motion command of each base-level controller. Each base-level controller controls one joint module to move according to the motion command. Modularized structure has been widely used in the design of hardware and software to enhance the error tolerance.The body-level controller based on ARM7 microprocessor and embedded real-time operating system is proposed, which has the features of real-time, reliability and extension. No only because huge real time data is transmitted between PC and body-level controller, but also for realizing robot modularization and extensibility interface of data bus with plug and play function the USB bus is chosen, and the application layer communication protocol is formulated.The based-level controller based on CAN bus, which is located on the base level of the robot's distributed control system architecture, is designed and realized. The microprocessor, dedicated motion controlling and driving chip, optical encoder are adopted to realize the joints'closed-loop servo motion control. CAN bus is introduced as the communication interface for different modules and it supports the multi joints'real-time control effectively.At last, we build the test platform of the modular reconfigurable walking robot. A serial of experiments are carried out including the multi joint coordinate locomotion experiment and the integrated arm and leg movement experiment. The results validate the distributed hierarchical control system of the modular reconfigurable walking robot. At the same time, a improvement scheme of gait generation is also proposed.