Robotic manipulator including pneumatic artificial muscle

A robotic manipulator, comprising: a platform (302); a first pair of pneumatic artificial muscle (PAM) devices (112,114) coupled to the platform (302) at a first end of the first pair of PAM devices; a second pair of PAM devices (116, 118) coupled to the platform (302) at a first end of the second pair of PAM devices; a first pulley (342) coupling the first pair of PAM devices via a first belt (132) at a second end of the first pair of PAM devices; a second pulley (344) coupling the second pair of PAM devices via a second belt (134) at a second end of the second pair of PAM devices; a U-joint (160) positioned between the first and second pulleys, wherein the first pulley (342), the second pulley (344), and the U-joint (160) are rotatable along a pitch axis (P1), a yaw axis (Y1), and a roll axis (R1); and an actuated object (170) coupled to the U-joint (160), wherein motion of one of the first belt (132) of the first pair of PAM devices, the second belt (134) of the second pair of PAM devices, and both the first belt (132) and the second belt (134), cause motion of the actuated object (170) along one of the pitch axis (P1), the yaw axis (Y1), and the roll axis (R1).

TECHNICAL FIELD

The present invention relates to robotic manipulators actuated by pneumatic artificial muscle (PAM) devices and methods of actuation, and in particular to pitch, roll, and yaw actuation of robotic manipulators.

BACKGROUND

A conventional pneumatic artificial muscle (PAM) or pneumatic muscle actuator generally comprises an internal bladder or tube surrounded by a braided mesh and attached at each end to a mechanical fitting, such as a header comprising female threads, a hook, a coupling, male threads, etc. Exemplary prior art pneumatic artificial muscles include those manufactured by Festo Corporation, the Shadow Robot Company, Kinetic Muscles Inc., and other manufacturers of the McKibben type actuators. When pressurized by a pneumatic source, the internal bladder or tube expands against the interior surface of the braided mesh, which constrains the overall bladder expansion causing the braid to shorten. Concurrently, as the bladder expands, the braid length contracts or decreases, thus producing a contraction force.

PAMs are widely used in factory floor automation, robotics, medical industries, and numerous other applications. The pulling force or bladder contraction when pressurized coupled with the fittings at the bladders two ends allows the actuators to produce an action, reaction, or work, such as toggling a switch or lifting a payload. As a typical PAM only generates a unidirectional force when pressurized by a pneumatic source, two PAMs are generally necessary when a bi-directional force is required. With two PAMs, the number of supporting devices to operate the PAMs, such as controllers, electronics, and a larger compressed pneumatic source, also increase. In a typical installation, the two PAMs are generally mounted in an antagonistic configuration to create a push and a pull. To create more degrees of freedom, more pairs of PAMS are required, typically a pair per degree of freedom (e.g., 3 pairs of PAMs for pitch, roll, and yaw actuation).

While using multiple PAMs in an application is a viable option, space or size of a particular application, funding and other constraints may make their use impracticable. Accordingly, there is a need for a pneumatic muscle actuator system that allows for high degrees of freedom without significantly added equipment, lower cost, and a smaller form factor.

In manufacturing environments, human operators work closely with robotic manipulators. With the manipulators' compliance (the ability of an object to yield elastically when a force is applied) and back drivability, these systems can provide safe operation. The stiffness of the actuator can be adjusted to satisfy the needs of the work environment.

In existing standard robotic manipulators, there is low to no compliance due to high gear ratios and high stiffness. This can be added to standard manipulators with added force torque sensors and advanced control algorithms. However, other solutions for controlled compliance and actuation of robotic manipulators are desirable.

SUMMARY

The present invention provides systems and methods for the controlled actuation of robotic manipulators with cost effectiveness and efficiency.

In accordance with an embodiment of the present invention, a robotic manipulator comprises: a platform; a first pair of pneumatic artificial muscle (PAM) devices coupled to the platform at a first end of the first pair of PAM devices; a second pair of PAM devices coupled to the platform at a first end of the second pair of PAM devices; a first pulley coupling the first pair of PAM devices via a first belt at a second end of the first pair of PAM devices; a second pulley coupling the second pair of PAM devices via a second belt at a second end of the second pair of PAM devices; a U-joint positioned between the first and second pulleys, wherein the first pulley, the second pulley, and the U-joint are rotatable along a pitch axis, a yaw axis, and a roll axis; and an actuated object coupled to the U-joint, wherein motion of one of the first belt of the first pair of PAM devices, the second belt of the second pair of PAM devices, and both the first belt and the second belt, cause motion of the actuated object along one of the pitch axis, the yaw axis, and the roll axis.

The above-mentioned robotic manipulator may have the following alternative components, which may also be combined in various applicable and functioning combinations within the scope of the present invention. In alternative embodiments, the robotic manipulator includes the following elements in complete or partial combination or each element alone: the U-joint includes a first link actuated by the first pulley and a second link actuated by the second pulley; the first pulley and the second pulley are positioned next to one another in parallel along the pitch axis; the first pulley, the second pulley, and the U-joint are coupled to a common pivot joint along the roll axis; the first pulley, the second pulley, and the U-joint are coupled to a common pivot joint along the yaw axis; the first pulley is independent of the second pulley; each of the PAM devices are independently actuatable; the first pair of PAM devices and the second pair of PAM devices are arranged in parallel planes along the pitch axis at rest; diagonally opposite PAM devices are actuatable to cause motion of the actuated object along the yaw axis; congruous motions of the first belt and the second belt cause motion of the actuated object along the pitch axis; antagonistic motions of the first belt and the second belt cause motion of the actuated object along the roll axis; a brake; control means operably coupled to the PAM devices for independent actuation of each of the PAM devices; each of the PAM devices are initially angled between about 45 degrees and about 90 degrees from a plane of the platform; and/or a slope of a top view projection of a PAM device and corresponding belt is less than 1, such that an X-axis length of the top view projection is greater than a Y-axis length of the top view projection.

In accordance with another embodiment of the present invention, a method of actuating a robotic manipulator is provided, the method comprising providing a robotic manipulator as described above, and actuating one of the first belt, the second belt, and both the first belt and the second belt, to cause motion of the actuated object along one of the pitch axis, the yaw axis, and the roll axis.

The above-mentioned method of actuating a robotic manipulator may have the following alternative steps, which may also be combined in various applicable and functioning combinations within the scope of the present invention. In alternative embodiments, the method includes the following elements in complete or partial combination or each element alone: actuating diagonally opposite PAM devices to cause motion of the actuated object along the yaw axis; actuating both PAM devices of one of the first and second pair of PAM devices to cause motion of the actuated object along the roll axis; actuating the first and second pair of PAM devices to cause antagonistic motions of the first belt and the second belt to cause motion of the actuated object along the roll axis; actuating the first and second pair of PAM devices to cause congruous motions of the first belt and the second belt to cause motion of the actuated object along the pitch axis; and/or actuating one PAM device of one of the first and second pair of PAM devices to cause motion of the actuated object along the pitch axis.

DETAILED DESCRIPTION

Four pneumatic artificial muscles (PAMs) (also referred to as pneumatic muscle actuators) are used for different robot designs in accordance with embodiments of the present invention. A PAM is a pneumatic bladder or pneumatic drive means that can extend or contract by regulating the inner air pressure via valves. PAMs can create unidirectional forces; therefore, two PAMs are paired to constitute an antagonistic PAM unit to provide motion flexibility. According to the present disclosure, arranging the paired PAM units result in three robot designs that possess different numbers of active joints and workspace.

Referring now toFIGS. 1A-1B, perspective views of a robotic manipulator system100are shown, the system including two sets of PAM devices, allowing an end effector or actuated object170to have two degrees of freedom.FIG. 1Bis a perspective view of the robotic manipulator system100ofFIG. 1Aafter actuation of one PAM device and pitch motion of the end effector170.

In accordance with embodiments of the present invention, robotic manipulator system100includes a platform102, a first pair of pneumatic artificial muscle (PAM) devices112,114fixedly coupled to the platform102at a first end of the first pair of PAM devices, and a second pair of PAM devices116,118fixedly coupled to the platform102at a first end of the second pair of PAM devices. PAM devices112,114,116,118can be fixedly coupled to fixed platform102by nuts and bolts122or other coupling means. System100further includes a first pulley142coupling the first pair of PAM devices112,114via a first belt132at a second end of the first pair of PAM devices, a second pulley144coupling the second pair of PAM devices116,118via a second belt134at a second end of the second pair of PAM devices, and a U-joint160positioned between the first pulley142and the second pulley144. The first pulley142, the second pulley144, and the U-joint160are rotatable along a pitch axis P1. First belt132can be fixedly coupled to PAM devices112,114and second belt134can be fixedly coupled to PAM devices116,118by nuts, bolts, and brackets124or other coupling means. The first pulley142, the second pulley144, and the U-joint160are positioned in a U-shaped housing150to be rotatable along pitch axis P1, which is perpendicular to the rotation plane of belts132and134in the rest position of PAM devices112-118. U-shaped housing150is fixedly coupled to a housing wall155. It is further noted that pulleys142and144and U-joint160are each positioned adjacent to one another along pitch axis P1but rotate in parallel planes perpendicular to the pitch axis P1.

End effector or actuated object170is coupled to the U-joint160, wherein motion of either the first belt132of the first pair of PAM devices112,114, or motion of the second belt134of the second pair of PAM devices116,118, or congruous motion of both belts132,134causes motion of the end effector170along the pitch axis P1.

FIG. 1Bis a perspective view of the robotic manipulator system100ofFIG. 1Aafter actuation of PAM device114, which results in contraction of PAM device114, actuation of belt132, rotation of pulley142, motion of U-joint160, and pitch motion of end effector170, as illustrated by raised U-joint160from horizontal.

In system100, two antagonistic PAM pairs are utilized, namely, PAM devices112and114, and PAM devices116and118. A five-bar mechanism (with five links, including ground) is utilized to yield a robot arm with 2 active joints (DoFs) which can generate motion along the pitch axis P1. Each PAM pair is connected to robot links via pulleys so as to convert translational PAM motion into rotational motion. The paired PAM units are isolated from each other, meaning that each paired PAM unit is specifically devoted to a certain joint. PAM devices112and114may independently actuate pulley142and a first link162, and PAM devices116and118may independently actuate pulley144and a second link164. Thus, two independent pitch motions may be actuated along pitch axis P1.

Accordingly, it is noted that other PAM devices112,116, or118can be actuated to cause pitch motion of end effector170. Actuation of PAM device116will also cause an upward pitch motion from horizontal of U-joint160and end effector170. Actuation of PAM device112or118will cause a downward pitch motion from horizontal of U-joint160and end effector170.

It is noted that system100is pictured with the PAM devices112-118initially or starting at about 90 degrees (about perpendicular) to the X-Y plane (and also the plane of platform102), but the PAM devices may be initially aligned between about 45 degrees to about 90 degrees to the X-Y plane (and also the plane of platform102).

Referring now toFIGS. 2A-2C, perspective views of another robotic manipulator system200are shown, the system including two sets of PAM devices allowing end effector170to have three degrees of freedom.FIG. 2Bis a perspective view of the robotic manipulator system ofFIG. 2Aafter actuation of one PAM device and pitch motion of the end effector170.FIG. 2Cis a perspective view of the robotic manipulator system ofFIG. 2Aafter actuation of a pair of PAM devices and roll motion of the end effector170. In accordance with embodiments of the present invention, robotic manipulator system200(similar to system100) includes platform102, first pair of pneumatic artificial muscle (PAM) devices112,114fixedly coupled to the platform102at a first end of the first pair of PAM devices, and second pair of PAM devices116,118fixedly coupled to the platform102at a first end of the second pair of PAM devices. PAM devices112,114,116,118can be fixedly coupled to platform102by nuts and bolts122or other coupling means.

System200further includes first pulley142coupling the first pair of PAM devices112,114via first belt132at a second end of the first pair of PAM devices, second pulley144coupling the second pair of PAM devices116,118via second belt134at a second end of the second pair of PAM devices, and U-joint160positioned between the first pulley142and the second pulley144. The first pulley142, the second pulley144, and the U-joint160are rotatable along a pitch axis P1and a roll axis R1. First belt132can be fixedly coupled to PAM devices112,114and second belt134can be fixedly coupled to PAM devices116,118by nuts, bolts, and brackets124or other coupling means. Belts132and134are used to connect their respective PAM device pairs and to transmit the motion from the actuation of the PAM devices to respective pulleys. The pulleys then transform the translational motion of the PAM devices to rotational motion for joint control.

The first pulley142, the second pulley144, and the U-joint160are positioned in a U-shaped housing250to be rotatable along pitch axis P1, which is perpendicular to the rotation plane of belts132and134in the rest position of PAM devices112-118. Within U-shaped housing250, pulleys142and144and U-joint160are each positioned adjacent to one another along pitch axis P1but rotate in parallel planes perpendicular to the pitch axis P1. U-shaped housing250is rotatably coupled to a housing wall255by a rotating joint252which allows U-shaped housing250to be rotatable along roll axis R1. End effector or actuated object170is coupled to the U-joint160, wherein motion of either the first belt132of the PAM device pair112,114, or motion of the second belt134of the PAM device pair116,118, or congruous motion of both belts132,134causes motion of the first and second pulleys142,144and U-joint160along the pitch axis P1and thereby pitch motion of end effector170, one example of which is illustrated inFIG. 2B. Congruous motion of one belt (i.e., either actuation of the first pair of PAM devices112,114or actuation of the second pair of PAM devices116,118) causes motion of housing250, the first and second pulleys142,144, and U-joint160along the roll axis R1and thereby roll motion of end effector170, one example of which is illustrated inFIG. 2C.

FIG. 2Bis a perspective view of the robotic manipulator system200ofFIG. 2Aafter actuation of PAM device118, which results in contraction of PAM device118, actuation of belt134, rotation of pulley144, motion of U-joint160, and thereby pitch motion of end effector170along pitch axis P1in a forward direction. Stretching of PAM devices112and114must be controlled when PAM device118is actuated in order to prevent a roll movement along roll axis R1. It is noted that actuation of PAM device112can cause a similar forward pitch motion of end effector170, and actuation of PAM device114or116can cause a pitch motion of end effector170in a backward direction or an opposite direction to that caused by actuation of PAM device112or118.

FIG. 2Cis a perspective view of the robotic manipulator system200ofFIG. 2Aafter actuation of both PAM devices116and118, which results in contraction of PAM devices116and118, actuation of belt134(pulling upward), pulling upward of pulley144and an end of housing250, roll motion of U-joint160, and thereby roll motion of end effector170along roll axis R1. It is noted that both PAM devices112and114can be actuated while PAM devices116and118are not actuated to cause roll motion of end effector170along roll axis R1in the opposite direction to the case shown when PAM devices116and118are actuated while PAM devices112and114are not actuated.

In system200, paired PAM units can be antagonistically driven to generate motion along the roll axis. On top of the existing structure in the 2 DoF design (FIGS. 1A-1B), PAM device pair112,114and PAM device pair116,118can work in an antagonistic fashion via a round belt to allow a base rotation along the roll axis R1, introducing the third DoF to the robot arm system.

It is further noted that roll movement along roll axis R1may also occur through the stretching of PAM devices112,114, and one of PAM devices116and118when they are loaded with the same pressure while the other one of PAM devices116and118is contracted. A mirroring pattern of stretching PAM devices116,118and one of PAM devices112and114with the same pressure while the other one of PAM devices112and114is contracted would also produce a roll movement along roll axis R1.

It is noted that system200is pictured with the PAM devices112-118initially or starting at about 90 degrees (about perpendicular) to the X-Y plane (and also the plane of platform102), but the PAM devices may be initially aligned between about 45 degrees to about 90 degrees to the X-Y plane (and also the plane of platform102).

Referring now toFIGS. 3A-1toFIG. 3D, perspective views of another robotic manipulator system300are shown, the system including two sets of PAM devices allowing an end effector to have four degrees of freedom.FIG. 3A-2illustrates top view projections of the PAM devices (and possibly belts) and distances between attachment points of the PAM devices and pulleys from each other.FIG. 3Bis a perspective view of the robotic manipulator system ofFIG. 3A-1after actuation of one PAM device and pitch motion of the end effector.FIG. 3Cis a perspective view of the robotic manipulator system ofFIG. 3A-1after actuation of a pair of diagonally-opposite PAM devices and yaw motion of the end effector.FIG. 3Dis a perspective view of the robotic manipulator system ofFIG. 3A-1after actuation of a pair of PAM devices and roll motion of the end effector170.

In accordance with embodiments of the present invention, robotic manipulator system300(similar to system200) includes platform302, first pair of pneumatic muscle actuators (PAM) devices112,114movably coupled to the platform302at a first end of the first pair of PAM devices, and second pair of PAM devices116,118movably coupled to the platform102at a first end of the second pair of PAM devices. PAM devices112-118can be movably coupled to platform302by universal joints322, ball and socket joints, or other movable coupling means. PAM devices112-118are coupled to platform302at attachment points312-318, respectively.

System300further includes a first pulley342coupling the first pair of PAM devices112,114via a first belt132at a second end of the first pair of PAM devices, second pulley344coupling the second pair of PAM devices116,118via second belt134at a second end of the second pair of PAM devices, and U-joint160positioned between the first pulley342and the second pulley344, wherein the first pulley342, the second pulley344, and the U-joint160are rotatable along a pitch axis P1, a roll axis R1, and a yaw axis Y1. First belt132can be fixedly coupled to PAM devices112,114and second belt134can be fixedly coupled to PAM devices116,118by nuts and bolts324or other coupling means.

The first pulley342, the second pulley344, and the U-joint160are positioned in a U-shaped housing350to be rotatable along roll axis R1, yaw axis Y1, and pitch axis P1. First pulley342, second pulley344, and U-joint160are positioned along pitch axis P1within U-shaped housing350but are rotatable in parallel planes perpendicular to pitch axis P1, which is also perpendicular to the rotation plane of belts132and134in the rest position of PAM devices112-118. U-shaped housing350is rotatably coupled to a housing wall355by a rotating joint352which allows U-shaped housing350to be rotatable along roll axis R1. U-shaped housing350is also rotatably coupled to a pivot joint380on a stand382by a bar384, which allows U-shaped housing350to be rotatable along yaw axis Y1.

End effector or actuated object170is coupled to the U-joint160, wherein motion of either the first belt132of the first pair of PAM devices112,114, or motion of the second belt134of the second pair of PAM devices116,118, or congruous motion of both belts132,134causes motion of the first and second pulleys142,144and U-joint160along the pitch axis P1and thereby pitch motion of end effector170, an example of which is shown inFIG. 3B. Actuation of diagonally opposite PAM devices cause motion of housing350, first and second pulleys342,344, and U-joint160, and thereby motion of the actuated object along the yaw axis, an example of which is shown inFIG. 3C. Congruous motion of one belt (i.e., actuation of the first pair of PAM devices112,114or the second pair of PAM devices116,118) causes motion of housing350, the first and second pulleys342,344, and U-joint160along the roll axis R1and thereby roll motion of end effector170, an example of which is shown inFIG. 3D.

In system300, the PAM device positions are changed from the systems100and200so that in the starting or initial position, the PAM devices are positioned with some angle with respect to the X, Y, and Z axes (systems100and200are pictured with the PAM devices112-118initially or starting at about 90 degrees or perpendicular to the X-Y plane but the PAM devices may be initially aligned between about 45 degrees to about 90 degrees to the X-Y plane). In one embodiment, the PAM devices112-118(their lengthwise axis) may be initially angled between about 45 degrees to about 90 degrees to the X-Y plane (and also the plane of platform302).

In system100and200, the preferred angle of the PAM devices is 90 degrees as shown inFIG. 1AandFIG. 2A. At this angle, said PAM devices provide maximum efficiency. In system300, the preferred angle of the PAM devices is between 45 degrees to 90 degrees in each of the yaw, pitch and roll axis as shown inFIG. 3A-1. More preferred angle in each of the three axes is between 45 degrees to 85 degrees, most preferably between 45 degrees to 60 degrees.

FIG. 3A-1andFIG. 3A-2illustrate projections of the PAM devices and distances between attachment points312,314,316, and318of the PAM devices112,114,116, and118, respectively, and pulleys342and344from one another. PAM device112is movably coupled to platform302at attachment point312, PAM device114is movably coupled to platform302at attachment point314, PAM device116is movably coupled to platform302at attachment point316, and PAM device118is movably coupled to platform302at attachment point318. A top view projection of PAM device112is illustrated as dashed line112p, a top view projection of PAM device114is illustrated as dashed line114p, a top view projection of PAM device116is illustrated as dashed line116p, and a top view projection of PAM device118is illustrated as dashed line118p. The distance between the center of attachment point312and the center of attachment point314is illustrated by dashed line Dm1, the distance between the center of attachment point314and the center of attachment point316is illustrated by dashed line Dm2, the distance between the center of attachment point316and the center of attachment point318is illustrated by dashed line Dm3, and the distance between the center of attachment point318and the center of attachment point312is illustrated by dashed line Dm4.

The diameter of pulleys342and344, as well as where the top view projections of the PAM devices (and belts) begin from the pulleys, are illustrated by dashed line Dp1. The distance between pulleys342and344(e.g., along pitch axis P1) is illustrated by dashed lines Dp2.

As shown by top view projections112p-118p, PAM devices112-118are angled with respect to the Y-Z plane as well as with respect to the X-Y plane (also plane of platform302). A Y-axis distance “a” and an X-axis distance “b” between the start of a PAM device top view projection leaving a pulley and a respective attachment point show the angle or slope of the PAM device's top view projection along the X-Y plane. In accordance with embodiments of the present invention, distance “b” is greater than distance “a” (b>a), such that a slope of a top view projection of a PAM device (and possible belt) is less than 1. In other words, the X-axis length (“run”) of the top view projection of a PAM device is greater than the Y-axis length (“rise”) of the top view projection of the PAM device.

In other embodiments, the first pair of PAM devices and the second pair of PAM devices may be arranged in parallel planes along the pitch axis at rest such that distance “a” would be zero.

FIG. 3Bis a perspective view of the robotic manipulator system300ofFIG. 3A-1after actuation of PAM device114, which results in contraction of PAM device114, actuation of belt132, rotation of pulley342, motion of U-joint160, and thereby pitch motion of end effector170along pitch axis P1. During this movement, roll and yaw movements may be negated and pitch movement enabled by controlled stretching in the other PAM devices112,116, and118. Otherwise, pitch movement may enabled through the closing of clutches in the system. As noted above, contraction of other PAM devices112,116, or118alone may likewise cause pitch motion in the same or opposite directions as illustrated inFIG. 3B.

FIG. 3Cis a perspective view of the robotic manipulator system300ofFIG. 3A-1after actuation of diagonally opposite PAM devices114and118, which results in contraction of PAM devices114and118, actuation of belts132,134in antagonistic motion causing a twisting motion to housing350and U-joint160, thereby causing yaw motion of end effector170along yaw axis Y1. Yaw motion is enabled by the contraction of transverse muscles, namely of PAM devices114and118or of PAM devices112and116. The direction of movement is provided by the force sequencing of the PAM devices. InFIG. 3C, a yaw movement is shown to be enabled by a more intense contraction of PAM devices114and118. It is noted that actuation of PAM devices112and116will cause yaw movement in the opposite direction to that caused by actuation of PAM devices114and118.

In addition to previously explained motions, PAM devices112and116can be pressurized simultaneously with the same pressure while PAM devices114and118can be pressurized with equal pressure to each other. Acting force differences and the time difference between pressurizing creates a motion on the yaw axis Y1.

FIG. 3Dis a perspective view of the robotic manipulator system300ofFIG. 3A-1after actuation of PAM devices116and118, which results in contraction of PAM devices116and118, congruous actuation of belt134(pulling upward), pulling upward of pulley344and an end of housing350, motion of U-joint160, and thereby roll motion of end effector170along roll axis R1. It is noted that congruous actuation and contraction of PAM devices112and114will cause a roll motion of end effector170in an opposite direction to that caused by actuation of PAM devices116and118.

Pulleys142and144, pulleys342and344, rotating joints252and352, and pivot joint380may include bearing systems for smooth rotational movement. Pulleys142and144, pulleys342and344, rotating joints252and352, and pivot joint380may further include breaking mechanisms to limit respective motions.

It is further noted that systems100,200, and300described above include a control unit for controlling the actuation of PAM devices (i.e., contraction, extension, or rest) and a power supply coupled to the control unit. Each PAM device may include other features, including but not limited to control valves, flow valves, load cells, pressure sensors, rotary encoders, and displacement sensors, which are operably coupled to the control unit.

Each PAM is coupled with a load cell to control the applied force. Basic stiffness control can be achieved using the load cells. Rotary encoders can be attached to the pitch, roll, and yaw axis (e.g., at joints252,352,380and pulleys342,344) to get joint positions and to control the position of the end effector.

Advantageously, the present invention provides for the controlled compliance and actuation of robotic manipulators with actuators at a remote location, efficient use of fewer actuators for movement with higher degrees of freedom, and pneumatic actuation, which provide a lower cost ratio and compact form factor with a high degree of control.

In accordance with a general embodiment of the present disclosure, a robotic manipulator comprises: a platform (302); a first pair of pneumatic artificial muscle (PAM) devices (112,114) coupled to the platform (302) at a first end of the first pair of PAM devices; a second pair of PAM devices (116,118) coupled to the platform (302) at a first end of the second pair of PAM devices; a first pulley (342) coupling the first pair of PAM devices via a first belt (132) at a second end of the first pair of PAM devices; a second pulley (344) coupling the second pair of PAM devices via a second belt (134) at a second end of the second pair of PAM devices; a U-joint (160) positioned between the first and second pulleys, wherein the first pulley (342), the second pulley (344), and the U-joint (160) are rotatable along a pitch axis (P1), a yaw axis (Y1), and a roll axis (R1); and an actuated object (170) coupled to the U-joint (160), wherein motion of one of the first belt (132) of the first pair of PAM devices, the second belt (134) of the second pair of PAM devices, and both the first belt and the second belt, cause motion of the actuated object (170) along one of the pitch axis, the yaw axis, and the roll axis.

The above-mentioned robotic manipulator may have the following alternative components, which may also be combined in various applicable and functioning combinations within the scope of the present invention. In alternative embodiments, the robotic manipulator includes the following elements in complete or partial combination or each selective element alone: the U-joint (160) includes a first link (162) actuated by first pulley (342) and a second link (164) actuated by second pulley (344); the first pulley (342) and the second pulley (344) are positioned next to one another in parallel along the pitch axis (P1); the first pulley (342), the second pulley (344), and the U-joint (160) are coupled to a common pivot joint (352) along the roll axis (R1); the first pulley (342), the second pulley (344), and the U-joint (160) are coupled to a common pivot joint (380) along the yaw axis (Y1); the first pulley (342) is independent of the second pulley (344); each of the PAM devices are independently actuatable; the first pair of PAM devices and the second pair of PAM devices are arranged in parallel planes along the pitch axis at rest; diagonally opposite PAM devices are actuatable to cause motion of the actuated object (170) along the yaw axis (Y1); congruous motions of the first belt (342) and the second belt (344) cause motion of the actuated object (170) along the pitch axis (P1); antagonistic motions of the first belt (342) and the second belt (344) cause motion of the actuated object (170) along the roll axis (R1); a brake; control means operably coupled to the PAM devices for independent actuation of each of the PAM devices; each of the PAM devices are initially angled between about 45 degrees and about 90 degrees from a plane of the platform (102or302); and a slope of a top view projection of a PAM device is less than 1, such that an X-axis length of the top view projection is greater than a Y-axis length of the top view projection.

In accordance with a general embodiment of the present disclosure, a method of robotic manipulator actuation comprises: providing a robotic manipulator as described above; and actuating one of the first belt (132), the second belt (134), and both the first belt (132) and the second belt (134), to cause motion of the actuated object along one of the pitch axis (P1), the yaw axis (Y1), and the roll axis (R1).

The above-mentioned method may have the following alternative steps, which may also be combined in various applicable and functioning combinations within the scope of the present invention. In alternative embodiments, the robotic manipulator actuation method includes the following steps in complete combination or each selective step alone: actuating diagonally opposite PAM devices to cause motion of the actuated object along the yaw axis; actuating both PAM devices of one of the first and second pair of PAM devices to cause motion of the actuated object along the roll axis; actuating the first and second pair of PAM devices to cause antagonistic motions of the first belt and the second belt to cause motion of the actuated object along the roll axis; actuating the first and second pair of PAM devices to cause congruous motions of the first belt and the second belt to cause motion of the actuated object along the pitch axis; and actuating one PAM device of one of the first and second pair of PAM devices to cause motion of the actuated object along the pitch axis.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. One skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. Moreover, it will be appreciated that various modifications and alterations may be made by those skilled in the art without departing from the scope of the invention.

Although the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate a number of variations, alterations, substitutions, combinations or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. For example, the use of different materials, different number of PAMs, and different configurations of PAMs are within the scope of the present invention. Furthermore, the various components that make up the robotic manipulator, and methods disclosed above can be alternatives which may be combined in various applicable and functioning combinations within the scope of the present invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description but is only limited by the scope of the appended claims.