A Small Mobile Hexapod Robot System With Four Wheels And A Manipulator

It’s a trend that the mobile robots help humans complete dangerous and complex tasks recently. However, in reality the unstructured and unknown environments the robots facing bring great difficulties to their motions and operations. But most of the traditional mobile robots have limited motion abilities, inflexible or even no manipulators and their detectors lack flexibility. In order to satisfy the requirements of robots’ detecting abilities and operation capabilities in complex environments, in this paper, a mobile robot system with wheels, legs and operating arm is designed and some experiments are carried out.The functional requirements and performance indexes of the robot system are determined according to the requirements of detection and operation. A small mobile hexapod robot system with four wheels and an operating arm is designed including a mobile platform, a rigid robotic arm, a flexible arm, a sensing system and a control system. The mobile platform with six legs and four wheels could satisfy well the different requirements of various environments and motions. When the surface is rough or there are steps before the robot, it can move with its legs. However, it can move fast with wheels on the smooth roads to improve the efficiency and reduce consuming of the energy. The rigid robotic arm with 4 DOFs realizes the control of end position and will be used for capture and maintenance when the end-effector is installed. The flexible arm consists of a spring and three wires and the camera on the tip of it can detect widely.According to the configuration and structure of the robot, the gait stability is analyzed, the gait planning based on a list of leg coordination rules is put forward and the embedded control system is developed. For better mobility, the kinematics of a single leg, the rigid arm and the whole system are analyzed. A list of leg coordination rules, the interactive relationship between legs, and the running process of the rules are proposed. Meanwhile the relationship between different velocities of rear wheels and the steering angles of front wheels is studied and operation principle of flexible arm is analyzed. The rationality of design is proved according to the simulation of ADAMS. The robot uses a WIFI camera and ultrasonic sensors to sense the surroundings. An embedded control system is designed based on a STM32 microprocessor. And the real-time operation system--RT-Thread system and some programs run on it. The PC programs are written in Microsoft Visual C++ 6.0. The communication between robot controller and PC is through WIFI and the operator can control the robot according to the videos from WIFI camera.A prototype is developed and typical experiments are performed. Experiment results verified the robot’s mobility, detection and operation capability.