Research On Six-foot Climbing Robot Based On ARM And FPGA

Based on the fact that multi-legged, wall-climbing robot is a specialized robot, which has the characteristics of redundancy-driving, multi-branched-chain and time-varying topology as a form of motion mechanism. By the design of an adsorption device under the feet(or abdomen),the project enables the robot to adapt to different planes. For example, the robot can not only walk upright and edge-on, but also can inverted-walk in the bottom of ceiling or walk across different walls. Generally, wall-climbing robot works in extremely harsh environment where humans are inconvenient to arrive, such as high altitude, strong corrosive and radiation situations. The climbing robot has a very important research significance and practical value, because it can be widely used in the fields of nuclear industry, petrochemical industry, architectural, transportation, fire-fighting and earthquake disaster. So, it has very good application prospect and market.Aiming at the six-foot, wall-climbing robot in complex environments, for example, flaw detection to large bridges newly-built or experienced earthquakes, this paper analyzes the issues associated with the mechanical structure of its body, hardware and software of the control System, crawling stability and gait planning of the robot.First, referring to the principle of bionics, after careful observation of beetles, the design puts forward the mechanical structure of six-foot, wall-climbing robot. It adopts hexagon as the body of the robot, installing a foot in the fuselage of each corner of the body. There are three active joints of each foot, each active joint is driven by Dynamixel AX-12 servo, so the robot has 18 servos. At the end of each foot, universal rotating hinge is used to connect the vacuum sucker, which adopts the vacuum adsorption for six-foot, wall-climbing robot to crawl at the vertical wall or against the bottom of ceiling.Then, the robot is designed to use ARM(Advanced RISC those) Cortex-M3 kernel microprocessor STM32 as the main controller of control system, and the FPGA chip of Altera company-Cyclone I series EP1C3T144 as coordinated controller. Communication mode between the main controller and coordinated controller is parallel communication mode, which includes address bus, data bus and control bus. The main controller is connected to CC1101 wireless communication module via a serial port, achieving communication between the robot and ground monitoring staff. By expanding the network adapter interface, the design realizes the uploading of videos collected by the camera. Moreover, the main controller detects signal of ultrasonic ranging avoidance obstacle module, so it can control algorithm of robot gait. By accepting gait data from the main controller, the coordinated controller converts the gait data into PWM signals, and controls the 18 servos by UART485. On the other hand, the coordinated controller gathers the signals of touch sensor and vacuum sensor under the foot, so it can switch the vacuum sucker adsorption, ensuring the security of the six-foot wall-climbing robot.Meanwhile, the static stability of the robot is analyzed in this paper when climbing, and the gait plan is put forward. The modes of three steps, four steps and five steps are analyzed in detail, and the gaits that control straight crawling, fixed-point rotation, and conversion from up-right to edge-on are presented. According to the gait plan, the corresponding single leg control program, straight crawling control program, as well as fixed-point turn control program are written.Last, after testing, the designed robot can crawl straight and step-over from ground to wall surfaces, proved to achieve the goals. It can be seen that the robot is full of practical significance in bridge detection and disaster relief in Sichuan area in the near future.