Not Applicable
Not Applicable
1. Field of the Invention
The invention relates to the field of robotic runners. More specifically, the invention comprises two rotating leg assemblies connected to a central body of a robot that is capable of running.
2. Description of Related Art
The application of robots and robotic machines has been used in many ways. This application varies from performing a task too tedious for a human or requiring such precision that a machine does the task more quickly and accurately. Recently, the focus of much of the research involving robotics has altered to different applications. Researchers have been developing robots that imitate the motion of living organisms. The technology includes robots that walk, climb, crawl, swim, and run.
Many biological systems and mechanics can be accurately modeled using simple mathematical or mechanical models. Because of this, the motion of living organisms has been replicated with surprising accuracy. The benefit of mimicking living creatures stems from the agility and adaptability of living organisms, for example, the wheels required to traverse grass are different from the wheels required to traverse concrete. While each set of wheels may work for both sets of environments, the efficiency may be reduced depending on the intended design. However, the legs of a larger animal traverse both environments with relatively equal efficiency. Thus, a robot with legs will have similar efficiency while traversing multiple environments.
Oftentimes using an active system will increase the stability of a robotic system. At times, this can actually be the only method to introduce any stability to the system. Typically, an active system requires expensive sensors and programming that sends corrective feedback to the control system integrated into the robot. This varies greatly from system to system. An example of a simple model of an active system is a tightrope walker. As the user reels himself or herself start to lean one way (sensors), he or she raises the opposite arm (control system) to prevent from falling. While this method can be advantageous, the sensors, controllers, and programming are expensive. In addition, these measures require space, add weight, increase electrical consumption, and increase complexity to the system. Thus, it is desired to achieve similar stability without these active control measures, if possible.
There are robotic systems that do not contain feedback and control systems. Typically, these systems comprise a slow moving (walking or crawling) robot with very little environmental disruption.
Therefore, what is needed is a lightweight, passively stable robot capable of traversing quickly over multiple terrains. The present invention achieves these objectives, as well as others, which are explained in the following description.
The present invention comprises a robotic system capable of traveling at high speeds using a set of rotating legs connected together. The invention may be operated without sensors, a controller, or feedback technology—though some embodiments optionally may include these features. The invention may he operated using only two controlled parameters—acceleration via the throttle setting and turning via the tilt of the main body of the system.
Each set of rotating legs contains at least, one leg and preferably two or more legs. The equivalent of a bipedal gait is established based on the rotation, compression, and spacing of the legs. The center of mass of the system is preferably low enough to die ground to keep the system stable without use of a control system. Applying torque between the center of mass and the hub allows for power and steering.
The present invention provides a robotic system capable of traveling at various speeds using rotating legs. The robot is capable of “running” at high speeds.
Linking tab 18 connects main body 12 to lower body 14. Lower body 14 is capable of housing necessary components, such as wiring, battery packs, or any other necessary components required for running robot 10 to operate. In addition, it is preferred than lower body 14 includes a balance weight (though a battery may serve this purpose adequately). In order to keep multi-legged running robot 10 stable, the majority of the weight of robot 10 is preferably located below the axis of rotation of leg assembly 16. This keeps the center of mass of the system relatively low and below the axis of rotation, if the center of mass is too high, robot 10 would be unbalanced and fall easily.
An important detail that contributes to the ability of robot 10 to travel at high speeds is the configuration of legs 20.
Rubber band 32 is an example of a bias device configured to urge the foot of a leg away from the axle. It restricts leg 20 in the opposite direction as leg catch 30. Rubber band 32 is wrapped around two pegs 34. As shown in the figure, each end of rubber band 32 is wrapped around separate pegs 34, then stretched over leg cap 34. While there is no force on foot end 28 of leg 20, the force created by stretched rubber band 32 keeps leg cap 26 firmly engaged to leg catch 30. However, when a force is applied to foot end 28 of leg 20, rubber band 32 is stretched further, allowing leg 20 to translate towards axle 36.
Rubber band 32 is one example among many possibilities of bias devices. One could also use a cod spring, a leaf spring, a compression block, or an air spring. One could also add a dampener operating in concert with the bias device. Likewise, the interaction between the leg catch and leg cap is only one example of a travel limiting device. There are many different mechanisms that could be used to limit the extension of the leg, in fact, some devices can function as both bias devices and travel-limiting devices. An example is a coil spring secured at both ends. The coil spring could limit extension while acting in tension and limit compression while acting in compression.
Although
As discussed in the preceding text, multi-legged running robot 10 includes main body 12. Main body 12 preferably includes a motor or motors that are attached to axle 36. As the motor turns axle 36, leg assembly 16 rotates. Robot 10 includes two leg assemblies 16. In a preferred embodiment (shown), each leg assembly 16 contains 3 legs 20. In order to imitate a bipedal gait, leg assemblies 16 are 60 degrees out of phase. This is demonstrated in
In addition, it is possible to offset the center of mass using a single main body for the robot. This single main body could be tilted relative to axle 36 in order to laterally shift the center of mass. As yet another embodiment, the entire main body could be shifted laterally along axle 36.
While it is the aim of the current invention to travel quickly on rotating legs without the use of sensors, a controller, or any feedback information, the reader will note that these instruments can fee integrated into the system. However, for those embodiments lacking a stability controller, certain design parameters should be taken into account.
First, the center of mass is preferably low enough to keep the robot stable while running. Second, the system is designed in such a way that the reaction force vectors created by the leg impacting a surface converge at a point just above the center of mass. This contributes to the stability of the system. Finally, the dampening in the legs allows the system to maintain high velocities while remaining stable.
Some general characteristics of the running robot, will apply to differing embodiments using differing numbers of legs. The robot mimics a bipedal running gait. Returning to
There must also be an angular phase difference in the rotation of the two leg assemblies. The phase difference is preferably 4 the angular spacing between the legs in a leg assembly. In the embodiment of
A driving motor or motors are provided to rotate the leg assemblies relative to main body 12. From the vantage point of
An embodiment using four legs in each leg assembly is possible. For such an embodiment the angular spacing between neighboring legs would be 360/4, or 90 degrees. The phase difference between the two leg assemblies would be 90/2, or 45 degrees. Embodiments with two legs per assembly are possible, as are embodiments with five or more legs per assembly.
Other variations which may be present in the preferred embodiments include:
1. Separate driving motors for the two leg assemblies so than the speed of rotation and phase-difference can be altered;
2. Orientation sensors to assist in actively controlling the robot; and
3. Position sensors to assist in actively controlling the robot.
The preceding description contains significant detail regarding the novel aspects of the present invention. It should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. Accordingly, the scope of the invention should be determined by reference to the following claims rather than the examples given.
This non-provisional patent application claims the benefit of an earlier-filed provisional application pursuant to 37 C.P.R. section 1.53(c). The provisional application listed the same inventors and was assigned Ser. No. 61/921,300.
Number | Date | Country | |
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61921300 | Dec 2013 | US |