Research On Leg-spherical Robots With Multi-motion Modes

For robots that perform probing and rescue missions in complex environments,they are required to adapt to a variety of road conditions and to have excellent performances in terms of speed,obstacle crossing ability,etc.The traditional multi-legged robots,although their obstacle crossing ability is strong,their movement speed is slow.On the contrary,spherical robots have fast movement,strong mobility,and even a zero turning radius,but they lack obstacle avoidance ability.Based on this,this paper develops a leg-spherical robot system with multi-motion modes.This robot system has the characteristics of the fast movement of the spherical robot and the high obstacle avoidance capability of the multi-legged robot.Furthermore,it can choose the appropriate form of movement according to different road conditions.According to the requirements of robot's movement ability under complex environments,the function and performance index of the mobile robot system are determined.Based on this index,the leg-spherical robot system is designed.The whole robot system consists of three parts: mechanical structures,sensors and embedded control system.In mechanical terms,we use spherical shell which can be spliced to wrapped with hexapod walking robots.To solve the mechanical interference during leg-sphere transformation,this paper designs a new expansion mechanism based on the Archimedes spiral,which avoids the possible mechanical interference between the upper and lower hemispheres.According to the design of the structure,we carried out the single-leg kinematic modeling and the whole system kinematic modeling.At the same time,the interaction between the legs is analyzed and the coordination rules are established.The movement gait of the hexapod's movement and the spherical rolling mode are planned.Moreover,ADAMS dynamic simulations are also made to verify the proposed design.The sensor system mainly uses a WIFI camera for environmental perception,and the camera can also transmit observed images to the control terminal through the wireless link.The control subsystem uses a STM32 chip and a wireless router as the core.The real-time operating system Open WRT is embedded and the task programs are prepared to realize the transformation of different robot motion patterns and the feedback of the sensing data.In addition,in order to facilitate the task planning and status monitoring,the PC software of the control terminal is written based on C#.Thus,the wireless communication between the embedded control subsystem and WIFI camera is achieved.Through this system,the robot can be remotely controlled.Finally,the prototype of the mobile robot is made and the experimental study is carried out.Results show that the proposed robot system has good athletic ability,deformation ability and rolling ability.