SolidSnake uses vertical and horizontal orthogonal joints to simulate the soft body of snake creatures. Every two orthogonal joints form a unit, and each unit is equivalent to a universal joint with two degrees of freedom, forming a highly redundant structure as a whole. This mechanism design enables the snake's body to bend in any direction. SolidSnake II, the second generation snake-like robot, fully considered the movement characteristics of snake-like creatures. From the perspective of bionics, combined with the relevant theories of robot dynamics and tribology, a snake kinematics model based on behavior control theory is established, which decomposes the complex motion forms of snake creatures into local and simple motion forms. With the modular design idea, each joint can be easily disassembled. The eight joints of the snake robot form a highly redundant structure, which is easy to imitate and realize the complex movement form of the snake. In order to reduce the friction resistance in the movement of the snake-shaped robot, driven wheels are installed on both sides of the snake-shaped robot, which realizes the smooth swimming of the snake body and enhances the flexibility and maneuverability of the snake-shaped robot. The main structure of the snake robot is made of light and wear-resistant plastic, which not only reduces the weight of the snake body, but also reduces the processing cost.
SolidSnake II snake robot is equipped with several reserved positions, such as local controller, position and torque servo, driven wheel locking device and other supporting devices, which can realize environment identification and autonomous movement of snake robot. The head of the snake robot is equipped with an infrared detector, which can feed back the monitoring data of the environment. The circuit design adopts 485 bus connection. The upper computer is controlled by PC, and the connector can be plugged and unplugged at any time by polling the bus regularly. This design can easily replace any joint, disassemble new joints at any time according to different tasks, and even realize live plugging and unplugging, which greatly enhances the reliability and durability of the snake-shaped robot. Moreover, SolidSnakeII built a perfect software and hardware development platform, which laid a solid foundation for the follow-up research and development. With the deepening of research, the research and application of snake-like robot will have a broader world. In 1970s, Professor Hirose from tokyo institute of technology began to study snake-shaped robots. Professor Hirose developed the first snake-like robot (Active Cordmanagement-ACM III) in 1972. The robot has a total length of 2 meters and 20 joints. The servo mechanism drives the joints to swing left and right. In order to contact the ground effectively, the robot's abdomen is equipped with casters. The robot has a maximum speed of 40cm/s and can only move on a plane. After the first snake-shaped robot, Professor Hirose's laboratory has successively developed a series of snake-shaped robots. ACM-R3 is a recent research achievement. ACM-R3 robot adopts completely wireless control mode, and each joint has its own power supply. Moreover, ACM-R3 is a three-dimensional structure, which can move in a three-dimensional environment and complete three complicated actions.
Takanashi of NEC Corporation of Japan developed a snake-shaped robot with rigid joints. The robot has a special joint structure, with six tubular links, the length of which is 1.4m, the diameter of which is 42mm, and the weight of which is 4.6kg It can realize three-dimensional space movement and can be applied to exploration and rescue in dangerous situations.
JPL, the national aeronautics and space administration of the United States, designed a snake-like robot using the snake-like robot structure of NEC company. The robot is about 1m long, 4cm in diameter, 3. 18kg in weight, and 12 in freedom, which is mainly used to complete tasks in the environment with obstacles.
GMD in Germany developed a snake-like robot. The robot is driven by ropes and has good flexibility. In addition, an infrared sensor is installed on the snake robot to detect environmental information.
In addition, many snake-shaped robots have been developed one after another, which will not be introduced here. The SINTEF institute in Norway has designed a snake-shaped robot for detecting the surface of Mars, and efforts are being made to improve it. This robot is similar in shape to a snake and can cross almost all obstacles like a snake.
Researchers believe that this snake-like robot can be an excellent tool for Mars exploration, and ESA seems to agree. SINTEF has just obtained 500,000 Norwegian kroner (about 85,000 US dollars) from the European Space Agency (ESA) to develop this snake-like robot.
Researchers at SINTEF University said that snake robots will not replace the existing Mars probes, and they are looking for a way to make these two tools work together.
"We are studying several alternatives to make the rover and snake robot work together. Because the rover has a powerful energy device, it can provide energy for snake robots through cables. If the snake robot must use its own battery, it will soon run out of energy, and then we will lose it. " Axel Trance, a senior research scientist at SINTEF University, explained.
"One option is to put the snake robot into the robotic arm of the rover and make it have the ability to disconnect and reconnect with the robotic arm, so that it can land on the surface of Mars and carry out independent activities." Transeth added.
This will be an ideal scheme for researchers. This scheme allows the rover to travel long distances, while the snake robot can explore those inaccessible places. Serpentine robots can drill holes, climb cliffs or enter narrow cracks for exploration activities by their own ability.
In an ideal situation, the snake robot can not only work with the rover, but also help it get out of trouble.
"The combination of the snake robot and the rover also means that if the rover gets stuck, the snake robot will be able to help it out." Parr Lierjeb, a senior researcher at SINTEF University? Ck said, "When the rover is trapped, the snake robot can land on the ground and circle around the surrounding rocks, so that the rover can get rid of the shackles with the help of the cable winch."
SINTEF hasn't made the moving prototype of this snake-shaped snake robot yet. But researchers say the work will be completed in a few months. In China, the research of snake-like robot has just started, but it has made rapid progress. The Robotics Research Institute of Harbin Institute of Technology, Shanghai Jiaotong University and other units first carried out some research work on bionic snake-like robots. Cui Heyu of Shanghai Jiaotong University developed the first miniature snake robot prototype in China in March 1999. This mechanism consists of a series of rigid links. The stepping motor controls the included angle between two adjacent rigid links, so that the links can swing in the horizontal plane. The bottom of the prototype is equipped with rolling bearings as passive wheels to change the ratio of longitudinal and transverse friction coefficients, and then some related theoretical studies have been carried out one after another. In 2002, the National University of Defense Technology developed a prototype of a snake-like robot. After using sealed skin, it can not only realize in-plane movement, but also realize meandering movement on the water surface.
The Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences has also started the research on snake-like robots, and put forward a new snake-like robot structure, which can realize a variety of planar and spatial motion forms adapted to the environment, and conducted in-depth theoretical research. Shenyang University of Aeronautics and Astronautics and other units have also started the research work of snake robots.