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Robot V
Robot V (Ajax) is another cockroach inspired robot, following in many ways after Robots III and IV. The robot uses the same joint architecture as the two previous robots: five joints in the front legs, four in the middle, and three in the rear, for a total of 24 degrees of freedom. The most noticeable difference between Robot V and its predecessors is its size. The previous two robots were 17 times the size of Blaberus discoidalis; Robot V is 20 times the size of the animal.
This animation shows the DOF of the front leg (3.4 megs).
To see larger pictures of the robot, click on either of the thumbnails:
Like Robot IV, Ajax uses braided pneumatic actuators to power all 24 degrees of freedom; however, these actuators are slightly modified variations of Fluidic Muscle made by the Festo Company instead of the in-house actuators used by Robot IV. Because these are pull-only devices, they must be used in opposing pairs. Two two-way valves control each actuator, allowing air to not only be inlet and exhausted, but trapped as well. As a result, the robot is able to control not only joint position, but also joint stiffness.
A movie of the robot standing can also be seen. Click on the below thumbnail (6 megs):
One very important property of the actuators used on Robot V is their inherent passive stability. When the robot is perturbed, it will naturally return to its equilibrium state. To see a movie of this, click the below thumbnail (5 megs):
Ajax is capable of maintaining a tripod stance, where the middle leg on one side, and the front and rear legs on the other side support the weight of the entire body. This is a necessity if tripod walking is to be achieved. While in this state, the robot exhibits the same passive stability properties as shown above. Click below to see the movie (3 megs)
The robot is also capable of switching from tripod to tripod. This is effectively walking--many of the leg motions are the same, althought there is very little forward motion. Note that there is a 5 pound payload on the back of the robot in this movie. (1.7 megs)
Tests are currently being performed to make the robot walk using an open loop controller. Once this task has been suffeciently accomplished, sensors will be added and a robust closed loop controller will be designed. Once again, there is a 5 pound payload onboard. (5 megs)
The first paper to be presented on Ajax will be at the International Symposium on Adaptive Motion of Animals and Machines which will be held in Kyoto, Japan, March 4-8 2003. The paper is entitled:
Kingsley, D. A., Quinn, R. D., Ritzmann, R. E., "A Cockroach Inspired Robot With Artificial Muscles" International Symposium on Adaptive Motion of Animals and Machines (AMAM 2003), Kyoto, Japan
Click here to download a copy of Daniel Kingsley's Dissertation HERE
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