13-07-2012, 02:22 PM
snake robots
[attachment=27556]
ABSTRACT
Man has created a machine named “Robot” which is capable of doing the work as instructed by man using its “Artificial Intelligence” (program code).The major problem the scientists of the field are facing is providing degrees of freedom to the robots. The scientists have come with a wonderful solution for this problem as snake robots. A snake robot is a power tool that can crawl to a job site on its own, parts in tow, and then carry out its assigned task. The Snake robot's structure is an engineer's dream it is easy to modify and repair because it's a repeating series of hinged segments.
This paper aims at presenting the importance of degrees of freedom for snake robots, their design. Motion planning for snake robots is difficult because the robots have many internal degrees of freedom that have to be coordinated to achieve purposeful motion. In motion planning the snake robots exist in large dimensional configuration spaces. They can be operated in several different modes from fully autonomous to human-guided. Some of the snake robot models designed and experimented by biometrics laboratories have been presented. With their applications in various fields like exploring the unknown worlds, Digging, surgical sciences etc.
INTRODUCTION
Ever since beginning man has zeal to have an honest servant who can do any thing for him, even the impossible’s .So; scientists have given a shape to this thought as “robotics” using Artificial Intelligence.
The first and foremost trouble the scientists faced is providing degrees of freedom to the robots. So the man once again relied on his old teacher “the nature” and its most wonderful creation snake, which has got the maximum possible degrees of freedom. So, scientists started to imitate the snake act and started developing robots which move like snake, which is nothing other than SNAKE ROBOTS.
Why snakes have high DOF (degrees of freedom):
Snakes are unique creatures in that their bodies allow them to get into the cracks and crevices of the world that most other creatures cannot. Lacking rigid skeletons and extremities, snakes can contort their bodies in order to get into tiny holes, wrap around tree branches and slither over otherwise unmanageable rocks. These serpentine qualities are the inspiration for a new type of robotic, interplanetary probe, called a snake Robot, being developed by engineers at NASA's Ames Research Center.
What is a snake Robot?
A snake robot is a power tool that can crawl to a job site on its own, parts in tow, and then carry out its assigned task. The snakebot's structure is an engineer's dream: it's easy to modify and repair because it's a repeating series of hinged segments. Think of an electric train; just add on as many cars as you want, and take off any you don't need. That's how a snake robot is arranged. Some of the modules on a snake robot can be duplicates. That way, if one area develops a problem, a new element can be snapped into its place. That makes maintaining and repairing the robot very manageable, especially in space where a repair shop isn't handy.
Snake Robots Designs:
The main concept of our design, as well as many others, is to stack two degree-of-freedom joints on top of each other, forming a snake robot. There are three main schools of designs for these kinds of robots: actuated universal joint, angular swivel joints and angular bevel joint. Actuated universal joint design: The simplest design that first comes to mind is stacking simple revolute joints as close as possible to each other and this led to the actuated universal joint design. However these kinds of designs tend to be bulky and slow, hence not appropriate of lots of snake robots applications. Another kind of bulky two DOF joints are pneumatic snakes.
Angular swivel joint: The second design that evolved was the angular swivel joints, which is present in the JPL Snake Robot. These are much more compact two DOF joints. The design is simple: starting with a sphere, then slicing the sphere into two parts such that the slice plane is transversal to the south-north pole axis of the sphere. Now rotate one half spheres with respect to the other and notice the motion of the North Pole as it traverses a cone of revolution. Connecting two adjacent snake bays via a passive universal joint and then by coordinating the rotation of the two spherical cups generated two degrees of freedom: In-plane bending and orientation.
Bevel joint: There are three types of bevel joints. They are:
1) Angular bevel.
2) Orientation preserving.
3) Double angular bevel.
Applications:
1) Surgical: In order to overcome the limitations of currently available assistive technologies for minimally invasive cardiac surgery (MICS), an innovative approach based on a highly articulated snake-robot probe (HARP). We hypothesize that, for procedures involving epicardial interventions on the beating heart, MICS can be effectively realized with the HARP, entering the pericardial cavity through a subxiphoid port, reaching remote intrapericardial locations.
2) Bridge inspection: Instead, an inspector, sitting in a truck on the bridge roadbed, will control a robot which can "view" the entire bridge through a sensor suite deployed at the end of the robot. This system would reduce the cost of bridge inspection, increase the safety factor, provide better views of the bridge, improve the quality of information, and as an added benefit, decrease traffic delays that are a result of such an operation. Conventional mobile robots and robot arms cannot adequately perform bridge inspection (painting, and paint-removing) because they lack the flexibility to reach all locations in highly convoluted structures which most bridges offer.
4) Digging: Using the high mechanical advantage from parallel systems and the ratcheting mechanism, Polybot can be used for digging or moving rocks. Digging or uncovering layers of planetary or cometary surfaces could be of key interest to planetary geologists. If this functionality is scaled up (either through larger modules, larger number of modules, or with longer term operation) it may also be useful in the preparation of terrain for the establishment of bases.
CONCLUSION:
In this paper we presented the importance of Degrees Of Freedom to a robot, how snake robots uses this concept of DOF, their design procedure and locomotion planning for these snake robots. There is a lot of scope for Research and development in this field.
[attachment=27556]
ABSTRACT
Man has created a machine named “Robot” which is capable of doing the work as instructed by man using its “Artificial Intelligence” (program code).The major problem the scientists of the field are facing is providing degrees of freedom to the robots. The scientists have come with a wonderful solution for this problem as snake robots. A snake robot is a power tool that can crawl to a job site on its own, parts in tow, and then carry out its assigned task. The Snake robot's structure is an engineer's dream it is easy to modify and repair because it's a repeating series of hinged segments.
This paper aims at presenting the importance of degrees of freedom for snake robots, their design. Motion planning for snake robots is difficult because the robots have many internal degrees of freedom that have to be coordinated to achieve purposeful motion. In motion planning the snake robots exist in large dimensional configuration spaces. They can be operated in several different modes from fully autonomous to human-guided. Some of the snake robot models designed and experimented by biometrics laboratories have been presented. With their applications in various fields like exploring the unknown worlds, Digging, surgical sciences etc.
INTRODUCTION
Ever since beginning man has zeal to have an honest servant who can do any thing for him, even the impossible’s .So; scientists have given a shape to this thought as “robotics” using Artificial Intelligence.
The first and foremost trouble the scientists faced is providing degrees of freedom to the robots. So the man once again relied on his old teacher “the nature” and its most wonderful creation snake, which has got the maximum possible degrees of freedom. So, scientists started to imitate the snake act and started developing robots which move like snake, which is nothing other than SNAKE ROBOTS.
Why snakes have high DOF (degrees of freedom):
Snakes are unique creatures in that their bodies allow them to get into the cracks and crevices of the world that most other creatures cannot. Lacking rigid skeletons and extremities, snakes can contort their bodies in order to get into tiny holes, wrap around tree branches and slither over otherwise unmanageable rocks. These serpentine qualities are the inspiration for a new type of robotic, interplanetary probe, called a snake Robot, being developed by engineers at NASA's Ames Research Center.
What is a snake Robot?
A snake robot is a power tool that can crawl to a job site on its own, parts in tow, and then carry out its assigned task. The snakebot's structure is an engineer's dream: it's easy to modify and repair because it's a repeating series of hinged segments. Think of an electric train; just add on as many cars as you want, and take off any you don't need. That's how a snake robot is arranged. Some of the modules on a snake robot can be duplicates. That way, if one area develops a problem, a new element can be snapped into its place. That makes maintaining and repairing the robot very manageable, especially in space where a repair shop isn't handy.
Snake Robots Designs:
The main concept of our design, as well as many others, is to stack two degree-of-freedom joints on top of each other, forming a snake robot. There are three main schools of designs for these kinds of robots: actuated universal joint, angular swivel joints and angular bevel joint. Actuated universal joint design: The simplest design that first comes to mind is stacking simple revolute joints as close as possible to each other and this led to the actuated universal joint design. However these kinds of designs tend to be bulky and slow, hence not appropriate of lots of snake robots applications. Another kind of bulky two DOF joints are pneumatic snakes.
Angular swivel joint: The second design that evolved was the angular swivel joints, which is present in the JPL Snake Robot. These are much more compact two DOF joints. The design is simple: starting with a sphere, then slicing the sphere into two parts such that the slice plane is transversal to the south-north pole axis of the sphere. Now rotate one half spheres with respect to the other and notice the motion of the North Pole as it traverses a cone of revolution. Connecting two adjacent snake bays via a passive universal joint and then by coordinating the rotation of the two spherical cups generated two degrees of freedom: In-plane bending and orientation.
Bevel joint: There are three types of bevel joints. They are:
1) Angular bevel.
2) Orientation preserving.
3) Double angular bevel.
Applications:
1) Surgical: In order to overcome the limitations of currently available assistive technologies for minimally invasive cardiac surgery (MICS), an innovative approach based on a highly articulated snake-robot probe (HARP). We hypothesize that, for procedures involving epicardial interventions on the beating heart, MICS can be effectively realized with the HARP, entering the pericardial cavity through a subxiphoid port, reaching remote intrapericardial locations.
2) Bridge inspection: Instead, an inspector, sitting in a truck on the bridge roadbed, will control a robot which can "view" the entire bridge through a sensor suite deployed at the end of the robot. This system would reduce the cost of bridge inspection, increase the safety factor, provide better views of the bridge, improve the quality of information, and as an added benefit, decrease traffic delays that are a result of such an operation. Conventional mobile robots and robot arms cannot adequately perform bridge inspection (painting, and paint-removing) because they lack the flexibility to reach all locations in highly convoluted structures which most bridges offer.
4) Digging: Using the high mechanical advantage from parallel systems and the ratcheting mechanism, Polybot can be used for digging or moving rocks. Digging or uncovering layers of planetary or cometary surfaces could be of key interest to planetary geologists. If this functionality is scaled up (either through larger modules, larger number of modules, or with longer term operation) it may also be useful in the preparation of terrain for the establishment of bases.
CONCLUSION:
In this paper we presented the importance of Degrees Of Freedom to a robot, how snake robots uses this concept of DOF, their design procedure and locomotion planning for these snake robots. There is a lot of scope for Research and development in this field.