Patent Description:
The painting of an aircraft is a challenging process due to the large amount of surface area and unique geometry of aircraft surfaces. For example, the nose and tail of an aircraft are typically highly contoured, which presents challenges in applying coatings in a precise manner. Adding to the challenge are complex paint schemes associated with an aircraft livery. For example, the livery of an airline may include images or designs that have complex geometric shapes and color combinations. In addition, an aircraft livery may include the name and logo of the airline, which may be applied to different locations on the aircraft such as the fuselage and the vertical tail. The process of applying the livery to the aircraft surfaces must be carried out with a high level of precision to meet aesthetic requirements, and to ensure that the coating thickness is within desired tolerances to meet aircraft performance (e.g., weight) requirements.

One method of painting an aircraft involves the use of individual robotic devices. Each robotic device includes an end effector mounted on a robotic arm. The robotic arm of each robotic device moves the end effector over the aircraft surfaces while the end effector dispenses any one of a variety of different paint colors, such as for applying an aircraft livery. Although the use of robotic devices reduces the amount of time required for aircraft painting relative to conventional manual methods that involve masking, painting, and demasking, the use of a single end effector on each robotic device results in a relative lengthy painting process.

To reduce the amount of time required for aircraft painting, an array of treatment devices can be assembled wherein each treatment device is configured to dispense paint onto the aircraft surfaces as the array is moved over the length of the aircraft. To provide a high level of flexibility in applying an aircraft livery, each treatment device includes a plurality of device heads. The devices heads must be assembled in close proximity to each other to allow for a high level of precision in applying the livery. In addition, each device head must be capable of being actuated along multiple axes to ensure that each device head is oriented complementary to the changing contours of the aircraft surfaces as the array of treatment devices is moved along the length of the aircraft. Existing mechanisms for actuating devices along multiple axes involve the use of rotary actuators. Unfortunately, rotary actuators are bulky, and are therefore difficult to package within a small area.

<CIT> discloses a processing device, a processing machine and a method for moving a machining head.

<CIT> discloses an assembly for treating contoured surface of commercial aircraft.

As can be seen, there exists a need in the art for a system for actuating a device along multiple axes, and which is capable of being packaged within a small area.

According to the present disclosure, a pitch-yaw actuation system and a method as defined in the independent claims are provided. Further embodiments of the claimed invention are defined in the dependent claims. Although the claimed invention is only defined by the claims, the below embodiments, examples, and aspects are present for aiding in understanding the background and advantages of the claimed invention.

The above-noted needs associated with actuating a device along multiple axes are addressed by the presently-disclosed pitch-yaw actuation system for actuating a device head. The pitch-yaw actuation system includes a pitch frame, a yaw frame, a pitch actuator, a yaw actuator, and a universal joint assembly. The pitch frame is configured to be pivotably coupled to a device frame via a pitch hinge having a pitch axis. The yaw frame is pivotably coupled to the pitch frame via a yaw hinge having a yaw axis orthogonal to the pitch axis. The pitch actuator is configured to pivot the pitch frame about the pitch axis. The yaw actuator is configured to pivot the yaw frame about the yaw axis. The universal joint assembly couples the yaw actuator to the yaw frame. The universal joint assembly includes a linear guide mechanism having a guide mechanism axis. In addition, the universal joint assembly includes a universal joint that is slidably coupled to the linear guide mechanism. The guide mechanism axis is oriented at an angle that allows the universal joint to move in a manner accommodating misalignment of the yaw actuator with the yaw frame during pivoting of at least one of the pitch frame and the yaw frame.

Also disclosed is a device head assembly, which includes a head frame and a pitch-yaw actuation system. The pitch-yaw actuation system includes a pitch frame, a yaw frame, a pitch actuator, a yaw actuator, and a universal joint assembly. The pitch frame is coupled to the head frame via a pitch hinge having a pitch axis. The yaw frame is coupled to the pitch frame via a yaw hinge having a yaw axis orthogonal to the pitch axis. The yaw frame is configured to receive a device head. The pitch actuator is coupled to the head frame and is configured to pivot the pitch frame about the pitch axis. The yaw actuator is coupled to the head frame and is configured to pivot the yaw frame about the yaw axis. The universal joint assembly is configured to couple the yaw actuator to the yaw frame. The universal joint assembly includes a linear guide mechanism having a guide mechanism axis. In addition, the universal joint assembly includes a universal joint that is slidably couplable to the linear guide mechanism. The guide mechanism axis is oriented at an angle allowing the universal j oint to move relative to the linear guide mechanism in a manner accommodating misalignment of the yaw actuator with the yaw frame during pivoting of the pitch frame and the yaw frame.

In addition, disclosed is a method of actuating a device head, which includes pivoting, using a pitch actuator, a pitch frame about a pitch axis of a pitch hinge coupling the pitch frame to a head frame. In addition, the method includes pivoting, using a yaw actuator, a yaw frame about a yaw axis of a yaw hinge coupling the yaw frame to the pitch frame. The yaw axis is oriented orthogonal to the pitch axis. The yaw actuator is coupled to the yaw frame via a linear guide mechanism and a universal joint slidably coupled to the linear guide mechanism. The method also includes moving the universal joint relative to the linear guide mechanism in a manner accommodating misalignment of the yaw actuator with the yaw frame during pivoting of at least one of the pitch frame and the yaw frame.

The features, functions and advantages that have been discussed can be achieved independently in various examples of the present disclosure or may be combined in yet other examples, further details of which can be seen with reference to the following description and drawings below.

These and other features of the present disclosure will become more apparent upon reference to the drawings wherein like numbers refer to like parts throughout and wherein:.

Referring now to the drawings which illustrate preferred and various examples of the disclosure, shown in <FIG> is an example of a treatment device system <NUM> for treating the article surfaces <NUM> of an article <NUM>. The treatment device system <NUM> includes an upper treatment device support assembly <NUM>, and a lower treatment device support assembly <NUM>, each configured to support an array <NUM> of treatment devices <NUM>. In the example shown, the article <NUM> is a fuselage <NUM> of an aircraft <NUM> having a vertical tail <NUM> and a pair of horizontal tails <NUM>. The fuselage <NUM> is shown supported on the floor <NUM> of a treatment facility <NUM> using fuselage support stands <NUM>.

The treatment devices <NUM> of each treatment device support assembly <NUM>, <NUM> are interconnected by a plurality of device actuation systems <NUM> (<FIG>) for actuating the treatment devices <NUM>. The device actuation systems <NUM> are configured to translate and/or rotate the treatment devices <NUM> in a manner to position each treatment device <NUM> complementary to an article surface <NUM> over which the treatment device system <NUM> is being moved.

As shown in <FIG> and described in greater detail below, each treatment device <NUM> includes a device frame <NUM>, and each treatment device <NUM> has one or more device heads <NUM>, which are shown arranged in rows and columns, and which are supported by the device frame <NUM>. As described in greater detail below, each device head <NUM> includes a pitch-yaw actuation system <NUM> (<FIG>) for pivoting the device head <NUM> about a pitch axis <NUM> (<FIG>) and a yaw axis <NUM> (<FIG>). The pitch-yaw actuation system <NUM> of each device head <NUM> is configured to orient the device head <NUM> complementary (e.g., locally normal) to the contour of an area of the article surface <NUM> (<FIG>) immediately adjacent to the device head <NUM> as the treatment devices <NUM> are moved over the article <NUM> (<FIG>).

Each of the device heads <NUM> is configured to dispense a treatment (not shown) toward and/or onto an article surface <NUM>. The treatment may be a coating, such as a primer, a paint, a clear coat, or a sealant. For painting an article <NUM> such as the fuselage <NUM> shown in <FIG>, each of the device heads <NUM> is an inkjet printhead <NUM> (e.g., a piezoelectric printhead or a thermal printhead) configured to precisely dispense ink onto the surfaces of the fuselage <NUM> as the treatment devices <NUM> are moved along the fuselage <NUM> for printing an aircraft livery. In other examples, the device heads <NUM> may be configured to dispense other types of treatments or substances, such as a solvent, an adhesive, a lubricant, abrasive particles, or any type of gas, liquid, semi-solid, or solid (e.g., particles) substance. In still further examples, the device heads <NUM> may be configured to emit radiation (e.g., electromagnetic radiation) for performing any one of a variety of operations on an article surface <NUM>.

Although described in the context of treating the surfaces of a fuselage <NUM>, the treatment device system <NUM> may be implemented for treating any one of a variety of different types of articles <NUM>, and is not limited to treating an aircraft <NUM>. For example, the treatment device system <NUM> may be implemented for treating vehicles such as ships, trains, or other ground-based motor vehicles such as trucks and automobiles. In addition, the treatment device system <NUM> may be implemented for treating stationary objects including, but not limited to, buildings, architectural objects, walls, and/or any one of a variety of other types of structures, systems, subsystems, assemblies, or subassemblies.

In <FIG>, the upper treatment device support assembly <NUM> includes a central pillar <NUM> coupled to an overhead gantry <NUM> (<FIG>). The fuselage <NUM> is oriented parallel to the lengthwise direction of the overhead gantry <NUM>, allowing the upper treatment device support assembly <NUM> to move the treatment devices <NUM> along the length of the fuselage <NUM>. A support structure base <NUM> is shown coupled to the central pillar <NUM>. On each of opposing sides of the support structure base <NUM> is a pillar pivot joint <NUM> coupling an attachment pillar <NUM> to the support structure base <NUM>. At the lower end of each attachment pillar <NUM> is an arm pivot joint <NUM> coupling a pair of attachment arms <NUM> to the attachment pillar <NUM>. The ends of the attachment arms <NUM> are respectively coupled via arm pivot joints <NUM> to opposite sides of an array <NUM> of treatment devices <NUM>. In the example shown, the upper treatment device support assembly <NUM> supports two arrays <NUM> of treatment devices <NUM>.

In <FIG>, the lower treatment device support assembly <NUM> is configured similar to the upper treatment device support assembly <NUM>. For example, the lower treatment device support assembly <NUM> includes a central pillar <NUM>, which is supported on a pit gantry <NUM> mounted in a pit <NUM> extending along a lengthwise direction below the floor <NUM> in parallel relation to the overhead gantry <NUM>. As shown in <FIG>, a support structure base <NUM> is mounted on the upper end of the central pillar <NUM>. A pair of pillar pivot joints <NUM> on opposite sides of the support structure base <NUM> respectively couple a pair of attachment pillars <NUM> to the support structure base <NUM>. The attachment pillars <NUM> extend upwardly through a pair of floor openings <NUM>. At the upper end of each attachment pillar <NUM> is an arm pivot joint <NUM> coupling a pair of attachment arms <NUM> to the attachment pillar <NUM>. The ends of the pair of attachment arms <NUM> extending from each attachment pillar <NUM> are coupled to opposite sides of an array <NUM> of treatment devices <NUM>. The lower treatment device support assembly <NUM> supports two arrays <NUM> of treatment devices <NUM>.

Referring to <FIG>, shown is the upper treatment device support assembly <NUM> supporting two arrays <NUM> of treatment devices <NUM>. Also shown is the lower treatment device support assembly <NUM> supporting two arrays <NUM> of treatment devices <NUM>. To facilitate positioning the treatment devices <NUM> relative to an article <NUM>, the attachment pillars <NUM> are rotatable about the pillar pivot joints <NUM>, and the attachment arms <NUM> are rotatable about the arm pivot joints <NUM>. The pivotability of the attachment pillars <NUM> and the attachment arms <NUM> allows the arrays <NUM> of treatment devices <NUM> to be positioned complementary to a variety of articles of different sizes and shapes.

Referring to <FIG>, shown is a single array <NUM> of treatment devices <NUM> of the lower treatment device support assembly <NUM> (<FIG>). The array <NUM> is supported on opposite ends respectively by a pair of attachment arms <NUM>. Each treatment device <NUM> includes a device frame <NUM>. As mentioned above, the device frames <NUM> of an array <NUM> are interconnected by device actuation systems <NUM>, which translate and rotate the device frames <NUM> relative to each other in a manner to position each treatment device <NUM> at a predetermined distance and orientation relative to the article surface <NUM>.

Each device actuation system <NUM> includes a drive rail <NUM> and at least one gear system <NUM>. As shown in <FIG>, the gear systems <NUM> respectively of adjacent pairs of treatment devices <NUM> are respectively mounted to the lateral sides <NUM> that generally face each other, thereby allowing adjacent pairs of treatment devices <NUM> to be interconnected by a drive rail <NUM>. Each gear system <NUM> has a first drive gear <NUM> and a second drive gear <NUM>. The drive rails <NUM> (<FIG>) are captured between the first drive gear <NUM> and the second drive gear <NUM> of the adjacent device frames <NUM>. The first drive gear <NUM> and the second drive gear <NUM> are each mounted on a drive shaft (not shown) extending through the lateral side <NUM> of the device frame <NUM>, and are respectively coupled to a first drive gear motor (not shown) and a second drive gear motor (not shown) inside the device frame <NUM>. The shaft of the second drive gear <NUM> extends through a device frame slot <NUM> (<FIG>) in the lateral side <NUM> of the device frame <NUM>.

To actuate the device frames <NUM>, the first drive gear <NUM> and the second drive gear <NUM> of each gear system <NUM> are rotated at the same or different speeds, and in the same or opposite directions, to cause translation and/or rotation of the device frames <NUM> relative to each other. The second drive gear <NUM> moves toward or away from the first drive gear <NUM> to maintain the second drive gear <NUM> in continuous engagement with the drive rail <NUM> against the first drive gear <NUM> as the device frame <NUM> rotates relative to the drive rail <NUM> during differential rotation of the first drive gear <NUM> and the second drive gear <NUM>.

Referring still to <FIG>, the device actuation systems <NUM> move the device frames <NUM> (i.e., the treatment devices <NUM>) between an expanded configuration (<FIG>) and a contracted configuration (not shown), and any configuration in between, to allow the array <NUM> of treatment devices <NUM> to match the local size, shape, and geometry of an article <NUM> (<FIG>) being treated by the treatment device system <NUM> (<FIG>). In the expanded configuration, the array <NUM> of treatment devices <NUM> has a V-shaped configuration as shown in <FIG> and <FIG>. The V-shaped configuration may be implemented for livery printing on tubular sections of the fuselage <NUM> (<FIG>), and at the nose section of the fuselage <NUM>. To facilitate livery printing at the tail section, an array <NUM> of treatment devices <NUM> may be moved into a semi-contracted or contracted configuration to allow the array <NUM> to fit between the vertical tail <NUM> (<FIG>) and one of the horizontal tails <NUM> (<FIG>). As may be appreciated, the treatment device system <NUM> may be operated in a manner to arrange an array <NUM> of treatment devices <NUM> in any one of a variety of configurations complementary to other areas of an aircraft <NUM> in addition to the fuselage <NUM>, such as on opposite sides of the vertical tail <NUM>.

Referring still to <FIG>, the treatment device system <NUM> includes a controller <NUM> (<FIG>) for controlling the movement of the components of the upper and lower treatment device support assemblies <NUM>, <NUM>. In this regard, the controller <NUM> controls the pivoting of the attachment pillars <NUM> about the pillar pivot joints <NUM>, the pivoting of the attachment arms <NUM> about the arm pivot joints <NUM>, and the movement of the device actuation systems <NUM> interconnecting the device frames <NUM>, thereby allowing the arrays <NUM> of treatment devices <NUM> to accommodate articles <NUM> (<FIG>) of different sizes and shapes. In addition, the controller <NUM> controls the pitch-yaw actuation systems <NUM> (<FIG>) for adjusting the pitch orientation and yaw orientation of the individual device heads <NUM> in each treatment device <NUM> to be complementary to the local contour of the article <NUM>, as described below.

The upper and lower treatment device support assemblies <NUM>, <NUM> (<FIG>) may include one or more sensors (not shown) mounted to the device frames <NUM> (<FIG>). The sensors may be provided as imaging devices (e.g., cameras), laser scanners, or other metrology devices configured to sense the article surfaces <NUM> (<FIG>). Each sensor is configured to continuously scan the topography of the article surface <NUM>, and continuously generate surface data representative of the local contour of the article surface <NUM> as the arrays <NUM> (<FIG>) of treatment devices <NUM> (<FIG>) are moved over the article <NUM>. For example, the sensors on each device frame <NUM> continuously sense the distance between the device frame <NUM> and the local article surface <NUM>, in addition to sensing the orientation of the nominal dispensing direction <NUM> (<FIG>) of the device heads <NUM> relative to the local contour of the article surface <NUM>. The nominal dispensing direction <NUM> may be described as the direction along which a treatment is dispensed from a device head <NUM> when the device head <NUM> is in its home position <NUM> (<FIG>), prior to pivoting of the device head <NUM> about the pitch axis <NUM> (<FIG>) or yaw axis <NUM> (<FIG>) using the pitch-yaw actuation system <NUM>.

The sensors continuously transmit surface data to the controller <NUM> (<FIG>). The controller <NUM> processes the surface data provided by the sensors, and controls the device actuation systems <NUM> (<FIG>) to maintain the device head <NUM> (<FIG>) of each treatment device <NUM> within a tolerance band (e.g., ± <NUM> inch) of a predetermined distance (e.g., up to <NUM> inch) from the article surface <NUM> (<FIG>). In addition, the controller <NUM> controls the device actuation systems <NUM> (<FIG>) to maintain the device frame <NUM> (<FIG>) of each treatment device <NUM> (<FIG>) at a generally perpendicular (e.g., ± <NUM> degrees) orientation relative to the local contour of the article surface <NUM>.

As shown in <FIG> and mentioned above, the device heads <NUM> in each treatment device <NUM> are arranged in two columns, resulting in the device heads <NUM> being positioned in side-by-side arrangement. Due to the side-by-side arrangement of the device heads <NUM> in each treatment device <NUM>, orienting the device frame <NUM> generally perpendicular to a curved article surface <NUM> (<FIG>) will result in at least one of the side-by-side device heads <NUM> being non-perpendicular to the local contour of the article surface <NUM>. Furthermore, the device actuation system <NUM> of each treatment device <NUM> is limited to rotating the device frame <NUM> about an axis (not shown) perpendicular to the device frame <NUM> lateral side <NUM> that contains the gear system <NUM>, and is incapable of rotating the device frame <NUM> about an axis (not shown) parallel to the lateral side <NUM> of the device frames <NUM> to accommodate the compound curvature of an article surface <NUM>.

Advantageously, the pitch-yaw actuation system <NUM> (<FIG>) disclosed herein provides the capability to adjust the pitch orientation and yaw orientation of each device head <NUM>, so that the dispensing direction <NUM> of each device head <NUM> can be oriented complementary to (e.g., perpendicular to) the local contour of the article <NUM>. More specifically, the pitch-yaw actuation system <NUM> of each device head <NUM> has the capability to pivot the device head <NUM> about a yaw axis <NUM> (<FIG>) that is parallel to the lateral side <NUM> of the device frame <NUM>. In addition, the pitch-yaw actuation system <NUM> of each device head <NUM> has the capability to pivot the device head <NUM> about a pitch axis <NUM> (<FIG>) oriented orthogonal to the yaw axis <NUM>. The combination of pivoting about the yaw axis <NUM> and pivoting about the pitch axis <NUM> allows the pitch-yaw actuation systems <NUM> to orient the dispensing direction <NUM> of each device head <NUM> to be locally perpendicular or normal to the area of the article surface <NUM> immediately adjacent to (i.e., directly underneath) the device head <NUM>.

Referring to <FIG>, shown is a treatment device <NUM> comprising a device frame <NUM> containing a plurality of device head assemblies <NUM> arranged in columns and rows, and which are packed in close proximity to each other within the device frame <NUM>. Although the present example shows two columns and six rows of device head assemblies <NUM>, a treatment device <NUM> may include any number of columns and any number of rows of device head assemblies <NUM>, including a single column and/or a single row. As mentioned above, a gear system <NUM> is coupled to the lateral side <NUM> of the device frame <NUM> for actuation of the device frame <NUM> relative to an adjacent device frame <NUM> via one of the device actuation systems <NUM> (<FIG>).

Referring to <FIG>, shown is one of the device head assemblies <NUM> of <FIG>. The device head assembly <NUM> includes a head frame <NUM> and a pitch-yaw actuation system <NUM>. In the example shown, the head frame <NUM> is generally hollow and has an orthogonal shape having a long depth relative to the length and width that define the cross-sectional shape of the head frame <NUM>. The head frame <NUM> has a head frame upper portion <NUM> and a head frame lower portion <NUM>. As described below, the pitch-yaw actuation system <NUM> is configured in a manner that capitalizes on the relatively long depth of the head frame <NUM>, and allows for a relatively large number of device head assemblies <NUM> (<FIG>) to be packed within a single device frame <NUM> (<FIG>).

The pitch-yaw actuation system <NUM> is mounted on the head frame upper portion <NUM>. A device head <NUM> is supported by the pitch-yaw actuation system <NUM>. As mentioned above, the device head <NUM> is configured to dispense a treatment along a dispensing direction <NUM> (<FIG>) of the device head <NUM>. In the example shown, the device head <NUM> is an inkjet printhead <NUM> configured to dispense ink. As shown in <FIG>, the inkjet printhead <NUM> includes a pair of fluid conduits <NUM> for supplying and returning ink to and from the inkjet printhead <NUM>. A flexible data cable <NUM> extends from the underside of the inkjet printhead <NUM> for controlling the operation of the inkjet printhead <NUM>. Although the pitch-yaw-actuation system is described in the context of supporting an inkjet printhead <NUM>, the pitch-yaw actuation system <NUM> can support any one of a variety of different types of device heads <NUM>.

Referring to <FIG>, the pitch-yaw actuation system <NUM> includes a pitch frame <NUM>, a yaw frame <NUM>, a pitch actuator <NUM>, a yaw actuator <NUM>, and a universal joint assembly <NUM>. The pitch frame <NUM> is pivotably coupled to the device frame <NUM> via a pitch hinge <NUM>. More specifically, the pitch hinge <NUM> pivotably couples the pitch frame <NUM> to the head frame <NUM>, and the head frame <NUM> is mountable to (i.e., inside) the device frame <NUM> as shown in <FIG>. The pitch hinge <NUM> has a pitch axis <NUM>. As shown in <FIG>, the pitch frame <NUM> includes a pair of pitch frame tabs <NUM> interconnected by a pitch frame connecting member <NUM>. The pitch frame tabs <NUM> are spaced apart from each other to define a pitch frame opening that is sized and configured to receive the device head <NUM>. The pitch frame connecting member <NUM> is shaped in a manner to avoid interfering with the pivoting of the device head <NUM> about the yaw axis <NUM>.

In the example shown, the pitch hinge <NUM> is integrated into the pitch frame <NUM> and the device frame <NUM>. For example, in <FIG>, the pitch hinge <NUM> includes a pitch hinge bore <NUM> formed in a head frame hinge post <NUM> extending upwardly from the head frame upper portion <NUM>. A pitch hinge bore <NUM> is also formed in the pitch frame <NUM>. A pitch hinge pin <NUM> extends through the pitch hinge bores <NUM> to thereby couple the pitch frame <NUM> to the head frame <NUM>. However, in another example not shown, the pitch-yaw actuation system <NUM> may include a pitch hinge <NUM> as a separate component coupling the pitch frame <NUM> to the head frame <NUM>.

The yaw frame <NUM> is pivotably coupled to the pitch frame <NUM> via a pair of yaw hinges <NUM> that define the yaw axis <NUM>. The yaw frame <NUM> is made up of a yaw frame first portion <NUM> and a yaw frame second portion <NUM>, which are separate members. The yaw frame first portion <NUM> and the yaw frame second portion <NUM> each have a yaw frame tab <NUM>. In addition, the yaw frame first portion <NUM> has a yaw frame arm <NUM> which extends downwardly from the yaw frame tab <NUM>. The yaw frame first portion <NUM> is pivotably coupled to the pitch frame tab <NUM> via a yaw hinge <NUM> on one side of the device head <NUM>. Likewise, the yaw frame second portion <NUM> is pivotably coupled to the pitch frame tab <NUM> via a yaw hinge <NUM> on an opposite side of the device head <NUM>. Each yaw hinge <NUM> includes yaw hinge pin <NUM> that extends into a yaw hinge bore <NUM> formed in the yaw frame first portion <NUM> or yaw frame second portion <NUM>. The pitch-yaw actuation system <NUM> is configured such that the yaw axis <NUM> (<FIG>) is orthogonal to the pitch axis <NUM> (<FIG>).

In the example shown, the device head <NUM> includes a pair of device head mounting tabs <NUM> for attaching the device head <NUM> to the yaw frame tabs <NUM> respectively of the yaw frame first portion <NUM> and the yaw frame second portion <NUM>. As shown in <FIG> and described below, each pitch frame tab <NUM> has a pair of pivot stops <NUM> on opposite sides of the yaw axis <NUM>. In the example shown, the pivot stops <NUM> are angled surfaces on the underside of each pitch frame tab <NUM>. During pivoting of the device head <NUM> about the yaw axis <NUM> (<FIG>), the upper surfaces of the yaw frame tabs <NUM> make contact with the pivot stops <NUM>, thereby limiting the range of pivoting motion of the device head <NUM>, and which may advantageously prevent the fluid conduits <NUM> (<FIG>) and data cable <NUM> (<FIG>) of the inkjet printhead <NUM> from contacting the inner sides of the head frame upper portion <NUM> during pivoting of the device head <NUM> about the yaw axis <NUM>.

As described above, the yaw hinges <NUM> are integrated into the yaw frame <NUM> and pitch frame <NUM>. However, in another example not shown, the yaw hinges <NUM> may be separate components from the yaw frame <NUM> and pitch frame <NUM>. In a still further example not shown, the yaw frame first portion <NUM> and the yaw frame second portion <NUM> may be interconnected by a yaw frame connecting member (not shown), which is preferably shaped in a manner to avoid interfering with pivoting of the device head <NUM> about the yaw axis <NUM>.

Referring still to <FIG>, the pitch actuator <NUM> is configured to pivot the pitch frame <NUM> (and the device head <NUM>) about the pitch axis <NUM>. The pitch actuator <NUM> is configured as a linear actuator <NUM> having an actuator axis <NUM> (<FIG>) extending along a depthwise direction of the head frame <NUM>. The pitch actuator <NUM> is located on a pitch actuator side of the device head assembly <NUM>. The actuator axis <NUM> of the pitch actuator <NUM> is oriented orthogonal to both the pitch axis <NUM> and the yaw axis <NUM>.

The pitch actuator <NUM> has a pitch actuator fixed portion <NUM> and a pitch actuator extendable portion <NUM>. The pitch actuator fixed portion <NUM> is fixedly couplable to the head frame <NUM> (<FIG>). The pitch actuator extendable portion <NUM> is axially movable for pivoting the device head <NUM> about the pitch axis <NUM>. The pitch actuator extendable portion <NUM> has a pitch actuator terminal end <NUM> (<FIG>) that is coupled to the pitch frame <NUM> on a side of the device head <NUM> opposite the pitch hinge <NUM>. As shown in <FIG>, the pitch actuator terminal end <NUM> is coupled to a clevis fitting <NUM> protruding from the pitch frame connecting member <NUM>.

The yaw actuator <NUM> is configured to pivot the yaw frame <NUM> (and the device head <NUM>) about the yaw axis <NUM>. In the example shown, the yaw actuator <NUM> is configured as a linear actuator <NUM> similar to the pitch actuator <NUM>. The yaw actuator <NUM> and the pitch actuator <NUM> are located on opposite sides of the head frame <NUM>. The yaw actuator <NUM> has an actuator axis <NUM> oriented orthogonal to both the pitch axis <NUM> and the yaw axis <NUM>. In addition, the actuator axis <NUM> of the yaw actuator <NUM> is generally parallel to the actuator axis <NUM> of the pitch actuator <NUM>.

Similar to the above-described arrangement of the pitch actuator <NUM>, the yaw actuator <NUM> has a yaw actuator fixed portion <NUM> and a yaw actuator extendable portion <NUM>. The yaw actuator fixed portion <NUM> is fixedly couplable to the head frame <NUM>. The yaw actuator <NUM> has a yaw actuator terminal end <NUM> that is coupled to the yaw frame arm <NUM> via the universal joint assembly <NUM>, as described in greater detail below.

In the example shown, the pitch actuator <NUM> and the yaw actuator <NUM> are each configured as an electric linear actuator <NUM> (<FIG>) having a small servomotor (not shown) driving a ballscrew mechanism (not shown). The servomotor and the ballscrew mechanism are contained within a cylindrical housing <NUM> (<FIG>). In addition, each electric linear actuator <NUM> has a pushrod <NUM> (<FIG>) which is threadably engaged to the ballscrew mechanism, and which extends out of the housing <NUM>. The housing <NUM> may be coupled to the head frame <NUM> via a gimbal mount (not shown). Rotation of the ballscrew mechanism via the servomotor causes axial motion of the pushrod <NUM> relative to the housing <NUM> for pivoting the device head <NUM> about the pitch axis <NUM> and yaw axis <NUM>. Although described as electric linear actuators, the pitch actuator <NUM> and the yaw actuator <NUM> may optionally be configured as a pneumatic linear actuator.

Referring to <FIG> and <FIG>, shown is an example of a universal joint assembly <NUM> coupling the yaw actuator <NUM> to the yaw frame <NUM>. The universal joint assembly <NUM> includes a linear guide mechanism <NUM> and a universal joint <NUM>. The linear guide mechanism <NUM> has a guide mechanism axis <NUM>. The universal joint <NUM> is slidably coupled to the linear guide mechanism <NUM>. The guide mechanism axis <NUM> is oriented at an angle that allows the universal joint <NUM> to move along the linear guide mechanism <NUM> in a manner accommodating misalignment of the yaw actuator <NUM> with the yaw frame <NUM> during pivoting of the pitch frame <NUM> and/or yaw frame <NUM>. For example, the linear guide mechanism <NUM> is configured to allow the universal joint <NUM> to translate along the linear guide mechanism <NUM> while the universal joint <NUM> rotates. In this manner, the universal joint assembly <NUM> allows simultaneous pivoting of the device head <NUM> about the pivot axis and the yaw axis <NUM>.

In the example of <FIG>, the universal joint <NUM> is a ball-and-socket joint <NUM>. The ball-and-socket joint <NUM> includes a ball <NUM> having a spherical shape, and a joint body <NUM> having a socket <NUM> configured to receive the ball <NUM>. The ball <NUM> is fixedly coupled to an end of the yaw frame arm <NUM> via a ball stud <NUM>. However, the universal joint <NUM> may be provided in any one of a variety of alternative configurations that provide universal rotation capability. For example, although not shown, the universal joint <NUM> may be configured as a Hooke joint comprised of two yoke fittings interconnected by a cross-shaped member, with one of the yoke fittings slidably coupled to the linear guide mechanism <NUM>, and the other yoke fitting fixedly coupled to the yaw frame arm <NUM>.

In <FIG>, the linear guide mechanism <NUM> is a guide pin <NUM> that is fixedly coupled to the yaw actuator terminal end <NUM>. The joint body <NUM> includes a guide pin bore <NUM> that is sized and configured to slidably receive the guide pin <NUM>. The joint body <NUM> has a joint body side face <NUM> (<FIG>) configured complementary to a terminal end side face <NUM> (<FIG>) of the yaw actuator terminal end <NUM>. During sliding movement of the joint body <NUM> along the guide pin <NUM>, the joint body side face <NUM> slides in close parallel (e.g., non-contacting) relation to the terminal end side face <NUM>, thereby preventing rotation of the joint body <NUM> about the guide pin <NUM>, which may otherwise complicate the dynamics for controlling yaw pivoting of the device head <NUM>.

Although the figures illustrate the guide pin <NUM> fixedly coupled to the yaw actuator terminal end <NUM>, and the guide pin bore <NUM> formed in the joint body <NUM>, in other examples not shown, the guide pin <NUM> may be fixedly coupled to the joint body <NUM>, and the guide pin bore <NUM> may be formed in the yaw actuator terminal end <NUM>. In another arrangement not shown, the ball <NUM> of the ball-and-socket joint <NUM> may be fixedly coupled to the yaw actuator terminal end <NUM>, and the guide pin <NUM> may be coupled to the yaw frame <NUM>. In such an arrangement, the guide pin <NUM> may be either fixedly coupled to the yaw frame arm <NUM> and slidable within a guide pin bore <NUM> in the joint body <NUM>, or the guide pin <NUM> may be fixedly coupled to the joint body <NUM> and slidable within a guide pin bore <NUM> in the yaw frame arm <NUM>.

Referring to <FIG>, which illustrates the pitch-yaw actuation system <NUM> viewed from the side, the guide mechanism axis <NUM> (e.g., the guide pin <NUM>) is oriented at an angle that allows the universal joint <NUM> (e.g., the joint body <NUM>) to move along the linear guide mechanism <NUM> in a manner accommodating misalignment of the yaw actuator <NUM> (<FIG>) with the yaw frame <NUM> (<FIG>) during pivoting of the pitch frame <NUM> (<FIG>) and/or the yaw frame <NUM> (<FIG>). Although not shown, the guide mechanism axis <NUM> is parallel to the pitch axis <NUM> when the pitch-yaw actuation system <NUM> is viewed along a direction parallel to the pitch axis <NUM>.

In <FIG>, the guide mechanism axis <NUM> is oriented at an acute angle relative to the pitch axis <NUM> when the pitch-yaw actuation system <NUM> is viewed along a direction parallel to the yaw axis <NUM>. In one example, the acute angle α of the guide mechanism axis <NUM> is approximately <NUM> degrees (e.g., ±<NUM> degrees). However, the guide mechanism axis <NUM> may be oriented in any one of a variety of different directions that accommodates misalignment of the yaw actuator <NUM> with the yaw frame <NUM> during pivoting motion of the device head <NUM>.

Referring still to <FIG>, when the pitch-yaw actuation system <NUM> is viewed from the side, the universal joint assembly <NUM> is located below the pitch hinge <NUM>, which is located below the yaw hinge <NUM>. However, in other examples not shown, the pitch-yaw actuation system <NUM> may be configured such that the universal joint assembly <NUM> is located between the pitch hinge <NUM> and the yaw hinge <NUM> when the pitch-yaw actuation system <NUM> is viewed from the side. Also shown in <FIG> are the above-mentioned pivot stops <NUM> incorporated into the pitch frame tabs <NUM> for limiting the range of pivoting motion of the device head <NUM> in either direction about the yaw axis <NUM>.

Referring to <FIG>, shown are illustrations of the device head <NUM> prior to and during pivoting motion using the pitch-yaw actuation system <NUM>. <FIG> shows the device head <NUM> in a home position <NUM>, prior to pivoting about the pitch axis <NUM> and yaw axis <NUM>. <FIG> is a magnified view of the universal joint assembly <NUM> showing the position of the joint body <NUM> on the guide pin <NUM> when the device head <NUM> is in the home position <NUM>. In the illustration, the ball stud <NUM> has a generally vertical orientation.

<FIG> shows the pitch actuator <NUM> pivoting the device head <NUM> downwardly about the pitch axis <NUM>, and <FIG> shows the pitch actuator <NUM> pivoting the device head <NUM> upwardly about the pitch axis <NUM>. <FIG> is a magnified view of the universal joint assembly <NUM> showing the rotation of the ball <NUM> within the joint body <NUM> of the universal joint <NUM> when the device head <NUM> is pivoted about the pitch axis <NUM>. The rotation of the ball <NUM> is evident from the non-vertical orientation of the axis of the ball stud <NUM> in <FIG>, relative to the vertical orientation of the ball stud <NUM> axis in <FIG>.

<FIG> shows the yaw actuator <NUM> pivoting the device head <NUM> about the yaw axis <NUM> while the device head <NUM> remains pivoted about the pitch axis <NUM>. <FIG> is a magnified view of the universal joint assembly <NUM> showing slightly more rotation of the ball <NUM> within the joint body <NUM> as a result of the pivoting of the device head <NUM> about the yaw axis <NUM>. Additionally, <FIG> shows the universal joint <NUM> repositioned along the linear guide mechanism <NUM> as a result of the device head <NUM> pivoting about the yaw axis <NUM>. As mentioned above, the joint body side face <NUM> slides in close parallel relation to the terminal end side face <NUM> as the joint body <NUM> slides along the guide pin <NUM>, thereby preventing rotation of the joint body <NUM> about the guide pin <NUM>. As illustrated in <FIG>, the combination of the universal joint <NUM> and linear guide mechanism <NUM> allows for simultaneous pivoting motion and yawing motion of the device head <NUM>, and thereby facilitates movement of the device head <NUM> within a wide range of motion.

Advantageously, the pitch-yaw actuation system <NUM> is configured to fit within a relatively small footprint or cross-sectional area. For example, the pitch-yaw actuation system <NUM> is configured such that the pitch frame <NUM>, the yaw frame <NUM>, the pitch actuator <NUM>, the yaw actuator <NUM>, and/or the universal joint assembly <NUM> are non-protruding from the cross-sectional perimeter of the head frame <NUM> when viewed along a direction parallel to the actuator axes <NUM>. As mentioned above, the small footprint of the pitch-yaw actuation system <NUM> allows for packing a large number of device head assemblies <NUM> within a single device frame <NUM> (e.g., see <FIG>). The small footprint is due in part to the orientation of the pitch actuator <NUM> and yaw actuator <NUM> parallel to the depthwise direction of the head frame <NUM>. In this regard, the use of linear actuators <NUM> (i.e., the pitch actuator <NUM> and the yaw actuator <NUM>) to provide the pivot-driving force, instead of more bulky rotary actuators, capitalizes on the relatively long depth of the head frame <NUM>, and keeps the pivot-driving forces away from contamination-sensitive article surfaces <NUM> directly underneath the inkjet printhead <NUM>.

Referring now to <FIG>, shown is a flowchart of operations included in a method <NUM> of actuating a device head <NUM> of a treatment device <NUM>. As described above and shown in <FIG>, a plurality of device heads <NUM> are supported in close proximity to each other within a device frame <NUM> of each treatment device <NUM>. <FIG> show arrays <NUM> of treatment devices <NUM> being moved along a fuselage <NUM> for treating the fuselage surfaces.

Step <NUM> of the method <NUM> comprises pivoting, using a pitch actuator <NUM>, a pitch frame <NUM> about a pitch axis <NUM> of a pitch hinge <NUM> coupling the pitch frame <NUM> to a head frame <NUM>. As shown in <FIG> and described above, the pitch frame <NUM> is coupled to the head frame hinge post <NUM>, which protrudes upwardly from the head frame <NUM>. In the example shown, step <NUM> of pivoting the pitch frame <NUM> about the pitch axis <NUM> comprises pivoting the pitch frame <NUM> about the pitch axis <NUM> of the pitch hinge <NUM> integrated into one side of the pitch frame <NUM>. As shown in <FIG> and described above, a pitch hinge pin <NUM> extends through the pitch hinge bores <NUM> respectively formed in the head frame hinge post <NUM> and the pitch frame <NUM>, to thereby couple the pitch frame <NUM> to the head frame <NUM>.

Step <NUM> of the method <NUM> comprises pivoting, using a yaw actuator <NUM>, a yaw frame <NUM> about a yaw axis <NUM> of a yaw hinge <NUM> coupling the yaw frame <NUM> to the pitch frame <NUM>. As shown in <FIG> and described above, the yaw axis <NUM> is oriented orthogonal to the pitch axis <NUM>. In addition, the yaw actuator <NUM> is coupled to the yaw frame <NUM> via a universal joint assembly <NUM>. As described above, the universal joint assembly <NUM> includes a linear guide mechanism <NUM> and a universal joint <NUM> slidably coupled to the linear guide mechanism <NUM>. In the example shown, step <NUM> of pivoting the yaw frame <NUM> about the yaw axis <NUM> comprises pivoting the yaw frame <NUM> about the yaw axis <NUM> of the yaw hinges <NUM> integrated into the pitch frame <NUM> and the yaw frame <NUM>. In addition, step <NUM> includes pivoting the yaw frame <NUM> about the yaw axis <NUM> defined by a pair of yaw hinges <NUM> respectively on opposite sides of the pitch frame <NUM>. For example, as shown in <FIG> and described above, on each side of the device head <NUM>, a yaw hinge pin <NUM> extends into a yaw hinge bore <NUM> formed in either the yaw frame first portion <NUM> or yaw frame second portion <NUM>.

In the example shown, step <NUM> of pivoting the pitch frame <NUM> is performed via the pitch actuator <NUM> configured as a linear actuator <NUM>. In this regard, step <NUM> of pivoting the pitch frame <NUM> is performed by a linear actuator <NUM> configured as an electric linear actuator <NUM> having a ballscrew mechanism (not shown) and a pushrod <NUM> threadably engaged to the ballscrew mechanism for axially moving the pushrod <NUM>. Likewise, step <NUM> of pivoting the yaw frame <NUM> is performed via the yaw actuator <NUM> configured as a linear actuator <NUM>, which may also be configured as an electric linear actuator <NUM> similar to the above-described pitch actuator <NUM>.

As shown in <FIG>, step <NUM> of pivoting the pitch frame <NUM> and step <NUM> of pivoting the yaw frame <NUM> are respectively performed by the pitch actuator <NUM> and the yaw actuator <NUM> located on opposite sides of the device head <NUM>. In the example shown, step <NUM> of pivoting the pitch frame <NUM> is performed by the pitch actuator <NUM> actuating along an actuator axis <NUM> oriented orthogonal to both the pitch axis <NUM> and the yaw axis <NUM>. Likewise, step <NUM> of pivoting the yaw frame <NUM> is performed by the yaw actuator <NUM> actuating along an actuator axis <NUM> oriented orthogonal to both the pitch axis <NUM> and the yaw axis <NUM>. As mentioned above, the actuator axis <NUM> of the pitch actuator <NUM> and the actuator axis <NUM> of the yaw actuator <NUM> are generally parallel to each other. Step <NUM> of pivoting the pitch frame <NUM> about the pitch axis <NUM> includes pivoting the pitch frame <NUM> about the pitch axis <NUM> located between the yaw axis <NUM> and the universal joint assembly <NUM>, as shown in <FIG>. However, in another example not shown, the universal joint assembly <NUM> may be located between the pitch axis <NUM> and the yaw axis <NUM>.

Step <NUM> of the method <NUM> comprises moving the universal joint <NUM> relative to the linear guide mechanism <NUM> in a manner accommodating misalignment of the yaw actuator <NUM> with the yaw frame <NUM> during pivoting of at least one of the pitch frame <NUM> and the yaw frame <NUM>. As indicated above, the universal joint assembly <NUM> couples the yaw actuator <NUM> to the yaw frame arm <NUM>. For examples in which the universal joint <NUM> is made up of a joint body <NUM> having a socket <NUM> containing a ball <NUM> as shown in <FIG>, step <NUM> comprises translating the joint body <NUM> along the linear guide mechanism <NUM>. Referring to <FIG>, translating the universal joint <NUM> along the linear guide mechanism <NUM> includes translating the universal joint <NUM> along the guide mechanism axis <NUM> oriented at an acute angle relative to the pitch axis <NUM> when the head frame <NUM> is viewed along a direction parallel to the yaw axis <NUM>. In the example shown, the universal joint <NUM> is translated along the guide mechanism axis <NUM> oriented at an angle of approximately <NUM> degrees.

Referring to <FIG>, step <NUM> of moving the universal joint <NUM> relative to the linear guide mechanism <NUM> comprises sliding a guide pin <NUM> within a guide pin bore <NUM>. In the example shown, the guide pin <NUM> is fixedly coupled to the yaw actuator terminal end <NUM>, and the guide pin <NUM> slides within a guide pin bore <NUM> in the joint body <NUM>. However, in other examples not shown, the guide pin <NUM> may be fixedly coupled to the joint body <NUM>, and the guide pin <NUM> slides within a guide pin bore <NUM> formed in the yaw actuator terminal end <NUM>. As shown in <FIG>, step <NUM> of moving the universal joint <NUM> relative to the linear guide mechanism <NUM> includes rotating the ball <NUM> within the socket <NUM> formed in the joint body <NUM> of the ball-and-socket joint <NUM>. The ball <NUM> rotates within the socket <NUM> during pivoting of the device head <NUM> about the pitch axis <NUM> and/or during pivoting of the device head <NUM> at about the yaw axis <NUM>.

The method <NUM> further includes discharging a treatment from a device head <NUM> supported by the pitch frame <NUM> and the yaw frame <NUM>. The treatment is discharged from the device head <NUM> prior to, during, and/or after pivoting of the device head <NUM> about the pitch axis <NUM> and/or yaw axis <NUM>. As mentioned above, the device head <NUM> is configured to dispense the treatment along a dispensing direction <NUM> toward an article surface <NUM> of an article <NUM>, such as for applying a livery to an aircraft fuselage.

Further the disclosure includes examples as follows:
There is provided a pitch-yaw actuation system for actuating a device head, comprising: a pitch frame configured to be pivotably coupled to a device frame via a pitch hinge having a pitch axis; a yaw frame pivotably coupled to the pitch frame via a yaw hinge having a yaw axis orthogonal to the pitch axis; a pitch actuator configured to pivot the pitch frame about the pitch axis; a yaw actuator configured to pivot the yaw frame about the yaw axis; a universal joint assembly coupling the yaw actuator to the yaw frame, and including: a linear guide mechanism having a guide mechanism axis; a universal joint slidably coupled to the linear guide mechanism; and the guide mechanism axis is oriented at an angle that allows the universal joint to move in a manner accommodating misalignment of the yaw actuator with the yaw frame during pivoting of at least one of the pitch frame and the yaw frame.

Preferably: at least one of the pitch actuator and the yaw actuator is a linear actuator.

Preferably, the linear actuator is an electric linear actuator having a ballscrew mechanism and a push rod threadably engaged to the ballscrew mechanism for axially moving the push rod.

Preferably, the yaw actuator and the pitch actuator are located on opposite sides of the yaw frame.

Preferably, the pitch actuator and the yaw actuator each have an actuator axis oriented orthogonal to both the pitch axis and the yaw axis.

Preferably, the pitch axis is located between the yaw axis and the universal joint.

Preferably, the linear guide mechanism is configured to allow the universal joint to translate along the linear guide mechanism while simultaneously rotating about the guide mechanism axis.

Preferably, the guide mechanism axis is oriented at an acute angle relative to the pitch axis when the pitch-yaw actuation system is viewed along a direction parallel to the yaw axis.

Preferably, the acute angle of the guide mechanism axis is approximately <NUM> degrees.

Preferably, the universal joint is a ball -and-socket joint having a ball, and a joint body having a socket configured to receive the ball.

Preferably, the linear guide mechanism comprises a guide pin, and a guide pin bore configured to slidably receive the guide pin.

Preferably, the yaw actuator has a yaw actuator terminal end; the universal joint has a joint body; the guide pin is fixedly coupled to the yaw actuator terminal end; and the guide pin bore is formed in the joint body.

Preferably, the pitch hinge is integrated into a common side of the pitch frame and the yaw frame.

Preferably, the yaw frame is configured to receive a device head configured to discharge a treatment.

Preferably, the yaw frame has a yaw frame opening configured to receive the device head, the pitch-yaw actuation system includes a pair of yaw hinges respectively on opposite sides of the pitch frame.

There is provided a device head assembly, comprising: a head frame; a pitch-yaw actuation system, including: a pitch frame coupled to the head frame via a pitch hinge having a pitch axis; a yaw frame coupled to the pitch frame via a yaw hinge having a yaw axis orthogonal to the pitch axis, the yaw frame configured to receive a device head; a pitch actuator coupled to the head frame and configured to pivot the pitch frame about the pitch axis; a yaw actuator coupled to the head frame and configured to pivot the yaw frame about the yaw axis; a universal joint assembly configured to couple the yaw actuator to the yaw frame, and including: a linear guide mechanism having a guide mechanism axis; a universal joint slidably couplable to the linear guide mechanism; and the guide mechanism axis is oriented at an angle allowing the universal joint to move relative to the linear guide mechanism in a manner accommodating misalignment of the yaw actuator with the yaw frame during pivoting of the pitch frame and the yaw frame.

Preferably, the head frame has a head frame cross-sectional perimeter; and at least one of the pitch frame, the yaw frame, the pitch actuator, the yaw actuator, and the universal joint assembly are configured to be non-protruding from the head frame cross-sectional perimeter when the head frame is viewed along a direction parallel to an actuator axis of the pitch actuator and the yaw actuator.

Preferably, the pitch hinge is integrated into the pitch frame and the head frame; and the yaw hinge is integrated into the yaw frame and the pitch frame.

Preferably, at least one of the pitch actuator and the yaw actuator is a linear actuator (<NUM>).

Preferably, the guide mechanism axis is oriented at an acute angle relative to the pitch axis when the head frame is viewed along a direction parallel to the yaw axis; and the guide mechanism axis is parallel to the pitch axis when the head frame is viewed along a direction parallel to the pitch axis.

There is provided a method of actuating a device head, comprising: pivoting, using a pitch actuator, a pitch frame about a pitch axis of a pitch hinge coupling the pitch frame to a head frame; pivoting, using a yaw actuator, a yaw frame about a yaw axis of a yaw hinge coupling the yaw frame to the pitch frame, the yaw axis oriented orthogonal to the pitch axis, the yaw actuator coupled to the yaw frame via a linear guide mechanism and a universal joint slidably coupled to the linear guide mechanism; and moving the universal joint relative to the linear guide mechanism in a manner accommodating misalignment of the yaw actuator with the yaw frame during pivoting of at least one of the pitch frame and the yaw frame.

Preferably, at least one of pivoting the pitch frame and pivoting the yaw frame are respectively performed by the pitch actuator and the yaw actuator, each configured as a linear actuator.

Preferably, at least one of pivoting the pitch frame and pivoting the yaw frame is respectively performed by an electric linear actuator.

Preferably, pivoting the pitch frame and pivoting the yaw frame are respectively performed by the pitch actuator and the yaw actuator located on opposite sides of the pitch frame.

Preferably, pivoting the pitch frame and pivoting the yaw frame are respectively performed by the pitch actuator and the yaw actuator each actuating along an actuator axis oriented orthogonal to both the pitch axis and the yaw axis.

Preferably, pivoting the pitch frame about the pitch axis comprises: pivoting the pitch frame about the pitch axis located between the yaw axis and the universal joint.

Preferably, translating the universal joint along the linear guide mechanism comprises: translating the universal joint along a guide mechanism axis oriented at an acute angle relative to the pitch axis when the head frame is viewed along a direction parallel to the yaw axis.

Preferably, translating the universal joint along the guide mechanism axis oriented at the acute angle comprises: translating the universal joint along the guide mechanism axis oriented at an angle of approximately <NUM> degrees.

Preferably, moving the universal joint relative to the linear guide mechanism comprises: rotating a ball within a socket formed in a joint body of a ball -and-socket joint.

Preferably, moving the universal joint relative to the linear guide mechanism comprises: sliding a guide pin within a guide pin bore.

Preferably, sliding the guide pin within the guide pin bore comprises: sliding the guide pin within the guide pin bore formed in a j oint body of the universal j oint, the guide pin fixedly coupled to a yaw actuator terminal end of the yaw actuator.

Preferably, pivoting the pitch frame about the pitch axis comprises: pivoting the pitch frame about the pitch axis of the pitch hinge integrated into one side of the pitch frame.

Preferably, pivoting the yaw frame about the yaw axis comprises: pivoting the yaw frame about the yaw axis defined by a pair of yaw hinges respectively on opposite sides of pitch frame.

Preferably, the method further comprises: discharging a treatment from a device head supported by the pitch frame and the yaw frame.

Claim 1:
A pitch-yaw actuation system (<NUM>) for actuating a device head (<NUM>), comprising:
a pitch frame (<NUM>) configured to be pivotably coupled to a device frame (<NUM>) via a pitch hinge (<NUM>) having a pitch axis (<NUM>);
a yaw frame (<NUM>) pivotably coupled to the pitch frame (<NUM>) via a yaw hinge (<NUM>) having a yaw axis (<NUM>) orthogonal to the pitch axis (<NUM>);
a pitch actuator (<NUM>) configured to pivot the pitch frame (<NUM>) about the pitch axis (<NUM>);
a yaw actuator (<NUM>) configured to pivot the yaw frame (<NUM>) about the yaw axis (<NUM>);
a universal joint assembly (<NUM>) coupling the yaw actuator (<NUM>) to the yaw frame (<NUM>), and including:
a linear guide mechanism (<NUM>) having a guide mechanism axis (<NUM>);
a universal joint (<NUM>) slidably coupled to the linear guide mechanism (<NUM>); and
the guide mechanism axis (<NUM>) is oriented at an angle that allows the universal joint (<NUM>) to move in a manner accommodating misalignment of the yaw actuator (<NUM>) with the yaw frame (<NUM>) during pivoting of at least one of the pitch frame (<NUM>) and the yaw frame (<NUM>).