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Frequently Asked Questions
What is passive-dynamic walking technology?
Why are you using it?
How does it work?
Is it true that passive-dynamic robots only walk downhill?
Can SIGMO walk on level ground and uphill?
What is passive-dynamic walking technology?
The use of "passive" in this phrase is defined in the fact that this technology does not use motors to create movement. "Dynamic" is relating to energy or to objects in motion. When used together, we get a object that moves (walks), using no motors or electricity. Early studies of this involved creating a bi-pedal device which used gravity as a source of energy. A slight slope was created, and the device was placed at the top, moving each leg in front of the other to proceed down the slope.
Why are you using it?
Most recent attempts to create humanoid walking robotics used many servo motors to achieve actuation. Several problems existed with this approach:
How does it work?
Passive dynamic robotics start very basic. The first part is a mechanical structure. A human would have a torso, two opposite-swinging arms, and two legs. The two legs may have fixed or free ankles, and each has a knee that prevents hyperextension (bending the leg too far forwards at the knee). Each arm is fixed to the opposing leg so that when the right leg swings forward, the left arm swings forward. This motion helps to balance us when we walk, otherwise humans would sway side to side. As it turns out, you only need a structure like this to create walking locomotion. Even though it sounds very simple, it is actually a little more complex. Many variables must be taken into account, such as the size of the robot, construction material, and slope of walking surface. Each limb must be manufactured to precise conditions in order to achieve accurate and consistent locomotion. If something is even a "little" wrong, it may not walk at all. At this present time there is no set way to dimension a bi-pedal robot, mostly it is by trial and error (through simulations) as each person's development is different.
Is it true that passive-dynamic robots only walk downhill?
Yes, without the use of an independent force walking on level ground or uphill cannot be sustained. Researchers at Cornell and MIT use small DC motors and springs to create a pulling tension to begin each leg's stride.
Can SIGMO walk on level ground and uphill?
Part of SIGMO's design is to enable it to walk uphill, on level, and down slopes. At this present time our design has not yet advanced to walking up and down stairs, but we hope to add this capatiblity in the near future.
Why are you using it?
How does it work?
Is it true that passive-dynamic robots only walk downhill?
Can SIGMO walk on level ground and uphill?
What is passive-dynamic walking technology?
The use of "passive" in this phrase is defined in the fact that this technology does not use motors to create movement. "Dynamic" is relating to energy or to objects in motion. When used together, we get a object that moves (walks), using no motors or electricity. Early studies of this involved creating a bi-pedal device which used gravity as a source of energy. A slight slope was created, and the device was placed at the top, moving each leg in front of the other to proceed down the slope.
Why are you using it?
Most recent attempts to create humanoid walking robotics used many servo motors to achieve actuation. Several problems existed with this approach:
-
complexity- each degree of freedom requires a motor and thus a control system.
expense- every motor used to create motion added more to the total cost of each project.
weight/energy efficiency- the vast amount of motors and control systems made early walking robots very heavy and hard to manuever. The weight put more strain on the motors, and used vastly more engery than is required today. Honda's ASIMO overcame a lot of these energy efficiency problems, although it still relies on servo motors for movement.
How does it work?
Passive dynamic robotics start very basic. The first part is a mechanical structure. A human would have a torso, two opposite-swinging arms, and two legs. The two legs may have fixed or free ankles, and each has a knee that prevents hyperextension (bending the leg too far forwards at the knee). Each arm is fixed to the opposing leg so that when the right leg swings forward, the left arm swings forward. This motion helps to balance us when we walk, otherwise humans would sway side to side. As it turns out, you only need a structure like this to create walking locomotion. Even though it sounds very simple, it is actually a little more complex. Many variables must be taken into account, such as the size of the robot, construction material, and slope of walking surface. Each limb must be manufactured to precise conditions in order to achieve accurate and consistent locomotion. If something is even a "little" wrong, it may not walk at all. At this present time there is no set way to dimension a bi-pedal robot, mostly it is by trial and error (through simulations) as each person's development is different.
Is it true that passive-dynamic robots only walk downhill?
Yes, without the use of an independent force walking on level ground or uphill cannot be sustained. Researchers at Cornell and MIT use small DC motors and springs to create a pulling tension to begin each leg's stride.
Can SIGMO walk on level ground and uphill?
Part of SIGMO's design is to enable it to walk uphill, on level, and down slopes. At this present time our design has not yet advanced to walking up and down stairs, but we hope to add this capatiblity in the near future.
Project Pages
Project Background
Started: April 18, 2005
Completed: In Progress
Funding: Personal
Budget: $2000
Members: Daniel Shope, Joshua Crouse, Zachary Bain, Daniel Houck, Nathan Neil
Description:
SIGMO is a humanoid robot designed to demonstrate the applications of passive dynamics technologies.