Robotic devices typically utilize rotary and linear actuators to actuate and control movement of joints having rotational degrees of freedom. Hydraulic actuators, and particularly hydraulic linear actuators, are generally favorable for applications requiring high torque. Some robots are anthropomorphic to represent or mimic, for example, a human arm or leg. Human arms and legs have rotational degrees of freedom, such as humeral rotation, wrist rotation, thigh rotation, and calf rotation.
Features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention; and, wherein:
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.
As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result.
As used herein, “adjacent” refers to the proximity of two structures or elements. Particularly, elements that are identified as being “adjacent” may be either abutting or connected. Such elements may also be near or close to each other without necessarily contacting each other. The exact degree of proximity may in some cases depend on the specific context.
An initial overview of technology embodiments is provided below and then specific technology embodiments are described in further detail later. This initial summary is intended to aid readers in understanding the technology more quickly but is not intended to identify key features or essential features of the technology nor is it intended to limit the scope of the claimed subject matter.
Although typical linear actuators have many benefits, for anthropomorphic robot applications, linear actuators can be problematic in achieving an anthropomorphic form factor and a high range of motion. For example, in such applications, the desired range of motion can be greater than 70 degrees. For instance, about 180 degrees is needed to approximate wrist or humeral rotation. Such ranges of motion can be difficult to achieve using a linear actuator in a form factor representing a human arm or leg.
Accordingly, a linear/rotary motion transforming device is disclosed that can provide the range of angular motion typical of anthropomorphic robot applications in a package that can fit within an anthropomorphic form factor. The linear/rotary motion transforming device can include a first member disposed along an axis. The device can also include a second member linearly movable along the axis and rotatable about the axis. A first connecting element can be pivotally coupled to the first member and the second member, and offset from the axis. The first member and the second member can be linearly and rotatably movable relative to one another. The device can further include a third member rotatable about the axis. The second member can be disposed along the axis between the first member and the third member. A second connecting element can be pivotally coupled to the second member and the third member, and offset from the axis. The second member and the third member can be linearly and rotatably movable relative to one another. In addition, the device can include a load input mechanism operably coupled to the second member or the third member. Load output can be transferred via the other of the second member or the third member.
In another aspect, a linear/rotary motion transforming device can include a first member disposed along an axis. The device can also include a second member linearly movable along the axis and rotatable about the axis. A first connecting element can be pivotally coupled to the first member and the second member, and offset from the axis. The first member and the second member can be linearly and rotatably movable relative to one another. The device can further include a third member rotatable about the axis. A second connecting element can be pivotally coupled to the second member and the third member, and offset from the axis. The second member and the third member can be linearly and rotatably movable relative to one another. Furthermore, the device can include a fourth member linearly movable along the axis and rotatable about the axis. A third connecting element can be pivotally coupled to the third member and the fourth member, and offset from the axis. The third member and the fourth member can be linearly and rotatably movable relative to one another.
One embodiment of a linear/rotary motion transforming device 100 is illustrated in
The linear/rotary motion transforming device 100 can also include a third member 130 that can also be rotatable bi-directionally in a direction 105 about the axis 101. As shown in the figures, the second member 120 can be disposed along the axis 101 between the first member 110 and the third member 130. A second connecting element 142a can be pivotally coupled to the second member 120 and the third member 130, such as via universal pivots 140, and offset 106 from the axis 101. The first member 110 and the third member 130 can be disposed at a fixed distance 107 from one another, and the second member 120 can translate between them. The fixed distance 107 can be maintained by housing 160. The second member 120 and the third member 130 can therefore be linearly and rotatably movable relative to one another and coupled via the second connecting element 142a. For example, as shown in the figure, the third member 130 can be fixed linearly by the housing 160 such that the second member 120 moves linearly within the housing while rotating relative to one another. In one aspect, a length 108 of the first connecting element 141a and a length 109 of the second connecting element 142a can be the same or different from one another.
In one aspect, the housing 160 can be configured to fit within an anthropomorphic form factor. Although a cylindrical housing is illustrated, any suitable housing shape can be utilized. In another aspect, the housing 160 can be configured to support structural loads, and can therefore form a structural part of a robot, such as an anthropomorphic limb. One benefit of the housing is that pinch points created by the moving members and connecting elements can be enclosed within the housing 160. In addition, moving parts can be lubricated within an oil bath within the housing 160.
It should be recognized that any number of additional connecting elements can be incorporated to couple the first member 110 and the second member 120 (illustrated by additional connecting element 141b) and/or the second member 120 and the third member 130 (illustrated by additional connecting element 142b). It should be further recognized that a universal pivot 140 can comprise various devices or systems capable of providing at least three rotational degrees of freedom, such as, a ball joint, a universal joint associated with a rotational member, or the like. Varying the connecting element lengths 108, 109 and offsets 103, 104 can impact the rotational characteristics and range of rotational motion of the linear/rotary motion transforming device 100.
In addition, the linear/rotary motion transforming device 100 can include a load input mechanism. In one embodiment, a load input mechanism 150a can be operably coupled to the second member 120 such that load output 151a is transferred via the third member 130. For example, the load input mechanism 150a can be configured to provide force in the linear direction 102, such as by causing linear displacement of the second member 120. In one aspect, the load input mechanism 150a can comprise an actuator, such as a linear actuator or a rotary actuator. As shown in
It should be recognized that although an outer structure of the load input mechanism/load output 150a/151b is shown as being fixed in
Another embodiment of a linear/rotary motion transforming device 200 is illustrated in
It should be recognized that although the first member 210 is shown as being fixed in
Yet another embodiment of a linear/rotary motion transforming device 300 is illustrated in
The linear/rotary motion transforming device 300 can also include a fourth member 340 that can be movable bi-directionally in a linear direction 302 along the axis 301 and can also be rotatable bi-directionally in a direction 306 about the axis 301. A third connecting element 343a, 343b can be pivotally coupled to the third member 330 and the fourth member 340, such as via universal pivots 345, and offset 331 from the axis 301. The third member 330 and the fourth member 340 can therefore be linearly and rotatably movable relative to one another and coupled via the third connecting element 343a. In one aspect, the second member 320 and the fourth member 340 can be move linearly in concert with one another while rotating differently. In a particular aspect, the second member 320 and the fourth member 340 can be constrained to move linearly in concert with one another. A fifth member 350 can be rotatable bi-directionally in a direction 308 about the axis 301. A fourth connecting element 344a, 344b can be pivotally coupled to the fourth member 340 and the fifth member 350, such as via universal pivots 345, and offset 341 from the axis 301. The fourth member 340 and the fifth member 350 can therefore be linearly and rotatably movable relative to one another and coupled via the fourth connecting element 344a. As shown in the figures, at least a portion of the third member 330 can be disposed radially outboard of the fourth member 340 and/or the fifth member 350. In one aspect, the first member 310 and the fifth member 350 can be disposed at a fixed distance 307 from one another, and the second member 320 and the fourth member 340 can translate between them. The fixed distance 307 can be maintained by the third member 330, such as by a housing 336 of the third member 330. It should be recognized that although pairs of connecting elements are shown between coupled members, any suitable number of connecting elements may be used.
By “folding back” the connection between the second member 320 and the third member 330, the overall length of the device 300 can be reduced compared to the devices 100 and 200 discussed hereinabove, while achieving a high range of angular motion that can approach the ranges of motion possible by the devices 100 and 200. In addition, utilizing the third member 330 to couple with the fourth and fifth members 340, 350 can impart additional range of motion to the device.
In addition, the linear/rotary motion transforming device 300 can include a load input mechanism. In one embodiment, a load input mechanism 360a can be operably coupled to the second member 320 such that load output 361a is transferred via the fifth member 350. For example, the load input mechanism 360a can be configured to provide force in the linear direction 302, such as by causing linear displacement of the second member 320 as shown and described hereinabove with regard to linear/rotary motion transforming device 100 and 200. In another embodiment, a load input mechanism 360b can be operably coupled to the fifth member 350 such that load output 361b is transferred via the second member 320. In one aspect, the load output can resist and/or dissipate energy from the load input, such as by incorporating a dampening mechanism. It should be recognized that a load input mechanism can be operably coupled to the first member, the second member, the third member, the fourth member, or the fifth member, such that load output is transferred via one of the other of the members.
It should be further recognized that although the first member 310 is shown as being fixed in
In accordance with one embodiment of the present invention, a method for facilitating transforming of linear/rotary motion is disclosed. The method can comprise providing a linear/rotary motion transforming device, having a first member disposed along an axis, a second member linearly movable along the axis and rotatable about the axis, a first connecting element pivotally coupled to the first member and the second member, and offset from the axis, wherein the first member and the second member are linearly and rotatably movable relative to one another, a third member rotatable about the axis, wherein the second member is disposed along the axis between the first member and the third member, and a second connecting element pivotally coupled to the second member and the third member, and offset from the axis, wherein the second member and the third member are linearly and rotatably movable relative to one another. Additionally, the method can comprise facilitating coupling of a load input mechanism to the second member or the third member, wherein load output is transferred via the other of the second member or the third member. In one aspect, the load input mechanism can be disposed proximate the first member or the third member, along the axis between the first member and the third member, or within the second member. It is noted that no specific order is required in this method, though generally in one embodiment, these method steps can be carried out sequentially.
It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.
Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.
As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
While the foregoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.