14-04-2011, 02:59 PM
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ABSTRACT
When people or animals get hurt, they can usually compensate for minor injuries and keep limping along, but for robots, even slight damage can make them stumble and fall. Now a robot scarcely larger than a human hand has demonstrated a novel ability: It can recover from damage -- an innovation that could make robots more independent.
The new robot, which looks like a splay-legged, four-footed starfish, deduces the shape of its own body by performing a series of playful movements, swiveling its four limbs. By using sensors to record resulting changes in the angle of its body, it gradually generates a computerized image of itself. The robot then uses this to plan out how to walk forward.
The researchers hope similar robots will someday respond not only to damage to their own bodies but also to changes in the surrounding environment. Such responsiveness could lend autonomy to robotic explorers on other planets like Mars -- a helpful feature, since such robots can't always be in contact with human controllers on earth. Aside from practical value, the robot's abilities suggest a similarity to human thinking as the robot tries out various actions to figure out the shape of its world.
Chapter 1
INTRODUCTION
1.1 ROBOTS
A robot is a mechanical or virtual, artificial agent. It is usually an electromechanical system, which, by its appearance or movements, conveys a sense that it has intent or agency of its own.
A typical robot will have several, though not necessarily all of the following properties:
• Is not 'natural' i.e. has been artificially created.
• Can sense its environment.
• Can manipulate things in its environment.
• Has some degree of intelligence or ability to make choices based on the environment or automatic control / pre-programmed sequence.
• Is programmable.
• Can move with one or more axes of rotation or translation.
• Can make dexterous coordinated movements.
• Appears to have intent or agency (reification, anthropomorphisation or Pathetic fallacy).
Robotic systems are of growing interest because of their many practical applications as well as their ability to help understand human and animal behavior, cognition, and physical performance. Although industrial robots have long been used for repetitive tasks in structured environments, one of the long-standing challenges is achieving robust performance under uncertainty. Most robotic systems use a manually constructed mathematical model that captures the robot’s dynamics and is then used to plan actions. Although some parametric identification methods exist for automatically improving these models, making accurate models is difficult for
complex machines, especially when trying to account for possible topological changes to the body, such as changes resulting from damage.
1.2. ERROR RECOVERY
Recovery from error, failure or damage is a major concern in robotics. A majority of effort in programming automated systems is dedicated to error recovery. The need for automated error recovery is even more acute in the field of remote robotics, where human operators cannot manually repair or provide compensation for damage or failure.
Here, its explained how the four legged robot automatically synthesizes a predictive model of its own topology (where and how its body parts are connected) through limited yet self-directed interaction with its environment, and then uses this model to synthesize successful new locomotive behavior before and after damage. These findings may help develop more robust robotics, as well as shed light on the relation between curiosity and cognition in animals and humans.
Chapter 2
SELF HEALING OR SELF MODELLING ROBOTS
2.1 THE STARFISH ROBOT
2.1.1 CHARACTERIZING THE TARGET SYSTEM
The target system in this study is a quadrupedal, articulated robot with eight actuated degrees of freedom. The robot consists of a rectangular body and four legs attached to it with hinge joints on each of the four sides of the robot’s body. Each leg in turn is composed of an upper and lower leg, attached together with a hinge joint. All eight hinge joints of the robot are actuated with Airtronics 94359 high torque servomotors. However, in the current study, the robot was simplified by assuming that the knee joints are frozen: all four legs are held straight when the robot is commanded to perform some action. The following table gives the overall dimensions of the robot’s parts.
Table 2.1.1 Overall dimensions of robot
All eight servomotors are controlled using an on-board PC-104 computer via a serial servo control board SV-203B, which converts serial commands into pulse-width modulated signals. Servo drives are capable of producing a maximum of 200 ouncinches of torque and 60 degrees per second of speed.
This four-legged robot can automatically synthesize a predictive model of its own topology (where and how its body parts are connected), and then successfully move around. It can also use this "proprioceptive" sense to determine if a component has been damaged, and then model new movements that take the damage into account.
The robot is equipped with a suite of different sensors polled by a 16-bit 32- channel PC-104 Diamond MM-32XAT data acquisition board. For the current identification task, three sensor modalities were used: an external sensor was used to determine the left/right and forward/back tilt of the robot; four binary values indicated whether a foot was touching the ground or not; and one value indicated the clearance distance from the robot’s underbelly to the ground, along the normal to its lower body surface. All sensor readings were conducted manually, however all three kinds of signals will be recorded in future by on-board accelerometers, the strain gauges built into the lower legs, and an optical distance sensor placed on the robot’s belly.
ABSTRACT
When people or animals get hurt, they can usually compensate for minor injuries and keep limping along, but for robots, even slight damage can make them stumble and fall. Now a robot scarcely larger than a human hand has demonstrated a novel ability: It can recover from damage -- an innovation that could make robots more independent.
The new robot, which looks like a splay-legged, four-footed starfish, deduces the shape of its own body by performing a series of playful movements, swiveling its four limbs. By using sensors to record resulting changes in the angle of its body, it gradually generates a computerized image of itself. The robot then uses this to plan out how to walk forward.
The researchers hope similar robots will someday respond not only to damage to their own bodies but also to changes in the surrounding environment. Such responsiveness could lend autonomy to robotic explorers on other planets like Mars -- a helpful feature, since such robots can't always be in contact with human controllers on earth. Aside from practical value, the robot's abilities suggest a similarity to human thinking as the robot tries out various actions to figure out the shape of its world.
Chapter 1
INTRODUCTION
1.1 ROBOTS
A robot is a mechanical or virtual, artificial agent. It is usually an electromechanical system, which, by its appearance or movements, conveys a sense that it has intent or agency of its own.
A typical robot will have several, though not necessarily all of the following properties:
• Is not 'natural' i.e. has been artificially created.
• Can sense its environment.
• Can manipulate things in its environment.
• Has some degree of intelligence or ability to make choices based on the environment or automatic control / pre-programmed sequence.
• Is programmable.
• Can move with one or more axes of rotation or translation.
• Can make dexterous coordinated movements.
• Appears to have intent or agency (reification, anthropomorphisation or Pathetic fallacy).
Robotic systems are of growing interest because of their many practical applications as well as their ability to help understand human and animal behavior, cognition, and physical performance. Although industrial robots have long been used for repetitive tasks in structured environments, one of the long-standing challenges is achieving robust performance under uncertainty. Most robotic systems use a manually constructed mathematical model that captures the robot’s dynamics and is then used to plan actions. Although some parametric identification methods exist for automatically improving these models, making accurate models is difficult for
complex machines, especially when trying to account for possible topological changes to the body, such as changes resulting from damage.
1.2. ERROR RECOVERY
Recovery from error, failure or damage is a major concern in robotics. A majority of effort in programming automated systems is dedicated to error recovery. The need for automated error recovery is even more acute in the field of remote robotics, where human operators cannot manually repair or provide compensation for damage or failure.
Here, its explained how the four legged robot automatically synthesizes a predictive model of its own topology (where and how its body parts are connected) through limited yet self-directed interaction with its environment, and then uses this model to synthesize successful new locomotive behavior before and after damage. These findings may help develop more robust robotics, as well as shed light on the relation between curiosity and cognition in animals and humans.
Chapter 2
SELF HEALING OR SELF MODELLING ROBOTS
2.1 THE STARFISH ROBOT
2.1.1 CHARACTERIZING THE TARGET SYSTEM
The target system in this study is a quadrupedal, articulated robot with eight actuated degrees of freedom. The robot consists of a rectangular body and four legs attached to it with hinge joints on each of the four sides of the robot’s body. Each leg in turn is composed of an upper and lower leg, attached together with a hinge joint. All eight hinge joints of the robot are actuated with Airtronics 94359 high torque servomotors. However, in the current study, the robot was simplified by assuming that the knee joints are frozen: all four legs are held straight when the robot is commanded to perform some action. The following table gives the overall dimensions of the robot’s parts.
Table 2.1.1 Overall dimensions of robot
All eight servomotors are controlled using an on-board PC-104 computer via a serial servo control board SV-203B, which converts serial commands into pulse-width modulated signals. Servo drives are capable of producing a maximum of 200 ouncinches of torque and 60 degrees per second of speed.
This four-legged robot can automatically synthesize a predictive model of its own topology (where and how its body parts are connected), and then successfully move around. It can also use this "proprioceptive" sense to determine if a component has been damaged, and then model new movements that take the damage into account.
The robot is equipped with a suite of different sensors polled by a 16-bit 32- channel PC-104 Diamond MM-32XAT data acquisition board. For the current identification task, three sensor modalities were used: an external sensor was used to determine the left/right and forward/back tilt of the robot; four binary values indicated whether a foot was touching the ground or not; and one value indicated the clearance distance from the robot’s underbelly to the ground, along the normal to its lower body surface. All sensor readings were conducted manually, however all three kinds of signals will be recorded in future by on-board accelerometers, the strain gauges built into the lower legs, and an optical distance sensor placed on the robot’s belly.
