Patent Description:
During the manufacture of aeronautical and aerospace vehicles, various components may be sanded and cleaned before or after an assembly process. For example, mandrels, wings, fuselage sections, and/or the like may be polished and cleaned, such as via a sanding process.

Typically, robotic sanding end effectors are powered through pneumatic motors. The pneumatic motors are operably coupled to the sanding effectors to facilitate high torque and high speed sanding operations. The pneumatic motors are generally directly attached and coaxial with an attachment point of the robot, such as at an end of an arm. Other robotic sanding effectors include electric motors.

Conventional robotic sanding end effectors have various drawbacks, including the following: issues with typical pneumatic motors, issues with motors (e.g., pneumatic or electric) associated with typical in-line coupling (the in-line coupling between the motor and the attachment point of the robot limits configurability of the system, and may also limit the reach of the end effector, such as in confined areas), and issues with typical fluid systems (typically manually dispensed or coupled to a remote and dedicated fluid supply). Additionally, certain conventional robotic sanders may be susceptible to being inadvertently activated.

Further, pneumatic motors are typically coupled to a remote and dedicated air supply. For example, the pneumatic motors are coupled to a source of compressed air via one or more air delivery tubes. The pneumatic motors are configured to ensure a desired amount of force and pressure exerted by the sanding head into a workpiece. The air delivery tubes coupled between the pneumatic motor and an air supply add weight and complexity to the overall system, as well as limit the range of the system.

In short, tethering the motor of the end effector to a source of air through air delivery tubes limits the mobility of the system. Further, the in-line coupling between the motor and the attachment point of the robot limits configurability of the system, and may also limit the reach of the end effector, such as in confined areas.

<CIT>, in accordance with its abstract, states "an automated drywalling system for applying joint compound or plaster to drywall pieces. The system includes a robotic arm and a mudding end effector coupled at a distal end of the robotic arm, the mudding end effector configured to apply joint compound or plaster to a target surface. The system can further include a computing device executing a computational planner that: generates instructions for driving the mudding end effector and robotic arm to perform at least one mudding task that includes applying joint compound or plaster, via the mudding the end effector, to one or more joints between a plurality of drywall pieces, the generating based at least in part on obtained target surface data; and drives the end effector and robotic arm to perform the at least one mudding task.

<CIT>, in accordance with its abstract, states "the disclosure concerns a sanding head for an abrasion arrangement, where the sanding head comprises an abrading drum with a centre axis and contact wheels at both ends of the abrading drum, where the contact wheels have the same or substantially the same centre axis as the abrading drum, and where the sanding head comprises a suspension swivel arrangement, and where the sanding head comprises at least one load sensor connected to at least one contact wheel. The disclosure also concerns an abrasion arrangement and a use of a sanding head. The object of the disclosure is to ensure an equal contact on the abrading drum as well as an equal contact over the entire length of the abrading drum, and where the disclosure can be used on plane, convex and/or concave surfaces.

<CIT>, in accordance with its abstract, states "an apparatus for surface finishing includes a robot and an end effector. The end effector includes a compliance wrist having an axis of movement and coupled to the robot and a grinder tool coupled to the compliance wrist. The robot is configured to controllably position the end effector in three-dimensional space. The compliance wrist is configured to bias the grinder tool to a biased position relative to the robot and enable the grinder tool to move relative to the robot in response to an external force acting upon the grinder tool.

<CIT>, in accordance with its abstract, states "the disclosure discloses polishing equipment. The equipment comprises a water collecting bin, a bottom plate, a mounting plate, a connecting plate and a water tank, wherein the water collecting bin is arranged at the middle position below the bottom plate, the two sides above the bottom plate are correspondingly provided with a fixing plate, and a supporting plate is installed above the fixing plates; a mounting plate is installed at the middle position above the bottom plate; and five groups of water guide pipes are uniformly mounted at the two ends of the upper portion of the interior of the mounting plate, the water guide pipes penetrate through the bottom plate and extend into the water collecting bin. The polishing equipment is provided with the water tank, a water suction pump and a spray head, water in the water tank is pumped into the spray head by the water suction pump, and the water can be uniformly sprayed out, so that not only can a grinding head be cooled, a grinding position is washed and the situation that the grinding head is damaged due to too high temperature is avoided, sparks generated by grinding can be extinguished, and therefore fire caused by the fact that the sparks cannot be extinguished in time is avoided.

<CIT>, in accordance with its abstract, states "the disclosure relates to a head for positioning a tool on irregular surfaces, formed by a tool-holder assembly which is coupled to a robot arm by means of a support, the tool-holder assembly being provided with a force sensor and distance detectors by means of which a control of the action of the robot arm for positioning the work tool with respect to the operating surface is established.

In <CIT>, there is described a mist coolant system for cutting machine tools comprising: a reservoir for cutting tool lubricant having means connected thereto for pressurizing lubricant received therein, a source of water under less pressure than the lubricant, a mixing chamber having passage, means connecting the reservoir and water source thereto and an outlet provided at one end thereof, check valve means provided within the passage means between the reservoir and the mixing chamber and preventative of water flow to the reservoir, temperature sensing means including means for being held in engagement with a cutting tool, valve means provided within the mixing chamber for the controlled restriction of the reservoir passage means, the valve means having the temperature sensing means operatively connected thereto, a source of air under pressure connected across the outlet end of the mixing chamber and including conduit means provided between the outlet side of the mixing chamber and the cutting tool for the reception of the water and lubricant mixture formed in the mixing chamber and dispersion thereof to the tool.

A need exists for a robotic sanding system having increased mobility. Further, a need exists for a robotic sanding system having increased range. Moreover, a need exists for a robotic sanding system that is able to operate in confined spaces and areas. Additionally, a need exists for a readily configurable robotic sanding system. Also, a need exists for a sanding system having increased reach, such as can be positioned in confined areas. Further, a need exists for a sanding system having a securely contained fluid supply. Also, a need exists for a sanding system that is not susceptible to being inadvertently activated.

With those needs in mind, certain examples of the present disclosure provide an end effector for a robotic sanding system.

There is provided an end effector for a robotic sanding system, the end effector comprising: a sanding head including a sander; an electric motor operatively coupled to the sander and contained within the end effector, wherein the motor is configured to rotate the sander; and one or more sensors coupled to the sanding head, wherein the one or more sensors are configured to detect presence of a metal within a predefined distance; and the motor is configured to be prevented from activation in response to the metal being outside of the predefined range.

There is further provided a robotic sanding method, comprising: providing an end effector with a sanding head including a sander configured to sand a surface of a workpiece, wherein an electric motor is coupled to the sander within the end effector, wherein one or more sensors are coupled to the sanding head, and wherein the one or more sensors are configured to detect presence of a metal within a predefined range; and preventing activation of the electric motor in response to the metal being outside of the predefined range.

In at least one example, the end effector includes a sanding head including a sander configured to sand a surface of a workpiece, and a motor operatively coupled to the sander. The motor is configured to rotate the sander to sand the surface of the workpiece. In at least one example, a coupler is configured to removably secure the end effector to an attachment interface of an arm of the robotic sanding system. The motor includes a first central longitudinal axis. The coupler includes a second central longitudinal axis. In at least one example, the first central longitudinal axis is offset from the second central longitudinal axis. In at least one example, the end effector further includes one or more sensors coupled to the sanding head. The one or more sensors are configured to detect presence of a metal within the predefined range. As an example, the motor is prevented from activation in response to the metal being outside of the predefined range.

In at least one example, the motor is an electric motor contained within the end effector.

In at least one example, the sanding head further includes one or more brushes configured to capture one or more of debris or cleaning fluid.

In at least one example, the end effector also includes a force compliance sub-system configured to ensure that the sanding head engages the workpiece with a predetermined force. For example, the force compliance sub-system includes rods, ball joints, linear slides that slidably retain the rods, and springs coupled to the rods and ball joints. The ball joints, the linear slides, and the springs cooperate to allow the sanding head to angularly and linearly comply with surfaces of the workpiece.

In at least one example, the end effector also includes a fluid delivery sub-system configured to dispense cleaning fluid onto one or both of the sander or the workpiece. For example, the fluid delivery sub-system includes a first fluid container retaining a cleaning agent, a second fluid container retaining a mixing fluid (such as water), a mixing chamber fluidly coupled to the first fluid container and the second fluid container, wherein the cleaning agent and the mixing fluid are combined in the mixing chamber to form the cleaning fluid, a fluid outlet fluidly coupled to the mixing chamber, wherein the cleaning fluid is dispensed out of the fluid outlet, and one or more pumps operatively coupled to one or more of the first fluid container, the second fluid container, or the mixing chamber. The one or more pumps are configured to pump the cleaning agent and the mixing fluid to the mixing chamber, and the cleaning fluid out of the fluid outlet onto one or both of the sander or the workpiece.

Certain examples of the present disclosure provide a robotic sanding system including one or more arms, one or more actuators operatively coupled to the one or more arms, and an end effector coupled to the one or more arms, as described herein.

Certain examples of the present disclosure provide a robotic sanding method that includes providing an end effector with a sanding head including a sander configured to sand a surface of a workpiece. An electric motor is coupled to the sander within the end effector. One or more sensors are coupled to the sanding head. The one or more sensors are configured to detect presence of a metal within a predefined range. The robotic sanding method also includes preventing activation of the electric motor in response to the metal being outside of the predefined range.

In at least one example, the electric motor includes a first central longitudinal axis. A coupler removably secures the end effector to an attachment interface of an arm of a robotic sanding system. The coupler includes a second central longitudinal axis that is offset from the first central longitudinal axis.

Certain examples of the present disclosure provide a robotic sanding method, including providing an end effector with a sanding head including a sander configured to sand a surface of a workpiece; operatively coupling an electric motor to the sander within the end effector, wherein the electric motor comprises a first central longitudinal axis; removably securing a coupler of the end effector to an attachment interface of an arm of a robotic sanding system, wherein the coupler comprises a second central longitudinal axis; offsetting the first central longitudinal axis from the second central longitudinal axis; coupling one or more sensors to the sanding head, wherein the one or more sensors are configured to detect presence of metal within a predefined range; and preventing activation of the electric motor in response to the metal being outside of the predefined range.

In at least one example, the robotic sanding method also includes providing the sanding head with one or more brushes configured to capture one or more of debris or cleaning fluid.

In at least one example, the robotic sanding method also includes ensuring, by a force compliance sub-system, that the sanding head engages the workpiece with a predetermined force.

In at least one example, the robotic sanding method also includes dispensing, by a fluid delivery sub-system, cleaning fluid onto one or both of the sander or the workpiece. In at least one example, said dispensing includes retaining a cleaning agent within a first fluid container; retaining water within a second fluid container; fluidly coupling a mixing chamber to the first fluid container and the second fluid container; combining the cleaning agent and the water in the mixing chamber to form a cleaning fluid; coupling a fluid outlet to the mixing chamber; and dispensing the cleaning fluid out of the fluid outlet. In at least one example, said dispensing also includes operatively coupling one or more pumps to one or more of the first fluid container, the second fluid container, or the mixing chamber; and pumping, by the one or more pumps, the cleaning agent and the water to the mixing chamber, and the cleaning fluid out of the fluid outlet onto one or both of the sander or the workpiece.

A robotic sanding system may comprise: one or more arms; one or more actuators operatively coupled to the one or more arms; and an end effector coupled to the one or more arms, wherein the end effector comprises: a sanding head including a sander configured to sand a surface of a workpiece; a motor operatively coupled to the sander, wherein the motor is configured to rotate the sander to sand the surface of the workpiece, wherein the motor comprises a first central longitudinal axis; a coupler configured to removably secure the end effector to an attachment interface of an arm of the robotic sanding system, wherein the coupler comprises a second central longitudinal axis, wherein the first central longitudinal axis is offset from the second central longitudinal axis; and one or more sensors coupled to the sanding head, wherein the one or more sensors are configured to detect presence of a metal within a predefined range, and wherein the motor is prevented from activation in response to the metal being outside of the predefined range. Optionally, the sanding head further comprises one or more brushes configured to capture one or more of debris or cleaning fluid. Optionally, the end effector further comprises a force compliance sub-system configured to ensure that the sanding head engages the workpiece with a predetermined force. Optionally, the force compliance sub-system comprises: rods; ball joints; linear slides that slidably retain the rods; and springs coupled to the rods and ball joints, wherein the rods, the ball joints, the linear slides, and the springs cooperate to allow the sanding head to angularly and linearly comply with surfaces of the workpiece. Optionally, the end effector further comprises a fluid delivery sub-system configured to dispense cleaning fluid onto one or both of the sander or the workpiece. Optionally, the fluid delivery sub-system comprises: a first fluid container retaining a cleaning agent; a second fluid container retaining a mixing fluid; a mixing chamber fluidly coupled to the first fluid container and the second fluid container, wherein the cleaning agent and the mixing fluid are combined in the mixing chamber to form a cleaning fluid; a fluid outlet fluidly coupled to the mixing chamber, wherein the cleaning fluid is dispensed out of the fluid outlet; and one or more pumps operatively coupled to one or more of the first fluid container, the second fluid container, or the mixing chamber, wherein the one or more pumps are configured to pump the cleaning agent and the mixing fluid to the mixing chamber, and the cleaning fluid out of the fluid outlet onto one or both of the sander or the workpiece.

Certain examples of the present disclosure provide a sanding end effector for a robotic sanding system. The end effector is lightweight and provides increased reach and range for the robotic sanding system. The robotic sanding system including the end effector is particularly well-suited for sanding and/or cleaning various components of aeronautical and aerospace structures, such as curved fuselages, wings, mandrels, and the like.

In certain examples, the robotic sanding system includes an electric motor coupled to a sanding head. The electric motor allows the end effector to be untethered from an air supply, thereby decreasing the weight of the end effector and the robotic sanding system, and improving mobility. The end effector is configured to be removably coupled to an attachment interface of an arm of the robotic system, such as through a modular coupler. The modular coupler allows the end effector to be removed from the arm without portions of the end effector remaining on the arm.

Certain examples of the present disclosure provide an end effector for a robotic sanding system. The end effector includes an extension plate. An attachment interface connects to a tool flange of an arm of the robotic sanding system. The attachment interface is removably coupled to the extension plate. The end effector also includes a sanding head, an electric motor coupled to the sanding head and configured to drive the sanding head, and one or more one or more sensors (such as inductive sensors) that are configured to prevent rotation of a sander of the sanding head unless the sanding head is in contact with a metal surface. In at least one example, an onboard dispensing system is configured to combine liquid and cleaning agent in a predefined ratio and dispense the combined liquid on a surface of a workpiece. In at least one example, the end effector also includes angular and linear compliance sub-system configured to allow the sanding head to be compliant with a curved surface of the workpiece and maintain a threshold force on the curved workpiece. As an example, the angular and linear compliance system includes a plurality of ball joints and springs coupled to the sanding head.

As described herein, a robotic sanding system includes an end effector including a sanding head including a sander configured to sand a surface of a workpiece, and a motor operatively coupled to the sander. The motor is configured to rotate the sander to sand the surface of the workpiece.

<FIG> illustrates a schematic block diagram of a robotic sanding system <NUM>, according to an example of the present disclosure. The robotic sanding system <NUM> includes one or more actuators <NUM> operatively coupled to one or more arms <NUM>. The one or more actuators <NUM> may be electric, hydraulic, pneumatic, or other such motors that are configured to move the arm(s) <NUM>.

An end effector <NUM> is coupled to a distal end of the arm <NUM>. The end effector <NUM> includes a coupler <NUM> that is configured to removably secure the end effector <NUM> to an attachment interface <NUM> of the arm <NUM>. The attachment interface <NUM> may be a tool flange. For example, the coupler <NUM> includes clamps, latches, plugs, sockets, electrical interfaces, and/or the like that removably couple to reciprocal features of the attachment interface <NUM>. In this manner, the end effector <NUM> may be selectively secured to, and removed from, the arm <NUM>.

The end effector <NUM> also includes a sanding head <NUM> that includes a sander <NUM> operatively coupled to a motor <NUM>. In at least one example, the motor <NUM> is an electric motor contained within the end effector <NUM>. The end effector <NUM> includes the motor <NUM>, instead of a separate and distinct pneumatic motor connecting to the sanding head <NUM> through air delivery tubes. As such, the end effector <NUM> is not tethered to an air supply through one or more air delivery lines. Further, the end effector <NUM> may be isolated and removed from the arm <NUM>, as the motor <NUM> is onboard the end effector <NUM> instead of on or within the arm <NUM> and/or connected to pneumatic lines secured to the arm <NUM> or other portions of the robotic sanding system <NUM>.

The sander <NUM> is rotatably coupled to a collar <NUM> of the sanding head <NUM>. The collar <NUM> provides a shroud, cover, or housing in, on, and/or to which the sander <NUM> is rotatably secured. In at least one example, the motor <NUM> is mounted over the collar <NUM>. In operation, the sander <NUM> is rotated at high speed and torque through the motor <NUM> to sand or otherwise polish a workpiece <NUM>, such as a metal component. The workpiece <NUM> may be a mandrel, wing, portion of a fuselage of an aircraft of aerospace vehicle, for example. Optionally, the workpiece <NUM> may be various other components, whether or not part of an aeronautical or aerospace vehicle, which are configured to be sanded, polished, smoothed, cleaned, and/or the like. For example, examples of the present disclosure may be used in relation to components in vehicles (such as aircraft, spacecraft, land vehicles, sea vehicles), fixed structures (such as within residential or commercial buildings), or the like.

The sanding head <NUM> may also include one or more brushes <NUM> coupled to the sander <NUM>. The brushes <NUM> may be secured around a circumference of the sander <NUM>. In other examples, the brushes may overlay a top of the sander <NUM>. The brushes <NUM> are configured to capture one or both of excess cleaning fluid and/or debris that may be generated during a sanding operation. Alternatively, the sanding head <NUM> may not include the collar <NUM> and/or the brushes <NUM>.

The end effector <NUM> also includes a plurality of sensors <NUM>, which are coupled to a portion of the sanding head <NUM>. The sensors <NUM> may be inductive sensors that are secured to the collar <NUM>, such as around a circumference the collar <NUM>. The sensors <NUM> are configured to detect presence of metal within a predefined range, such as <NUM> millimeters or less. Optionally, the predefined range may be less than <NUM> millimeters, such as <NUM> millimeters, or greater than <NUM> millimeters, such as <NUM> millimeters. The sensors <NUM> are operatively coupled to the motor <NUM>, such as through one or more relays.

In operation, the sensors <NUM> prevent the motor <NUM> from operating when the sanding head <NUM> is outside of the predefined range of the workpiece <NUM>. For example, the motor <NUM> is prevented from activation in response to metal of the workpiece <NUM> being outside of the predefined range. If a portion of the workpiece <NUM> (such as a metal portion) is within the predefined range of all of the sensors <NUM>, the motor <NUM> may activate and operate to rotate the sander <NUM> to sand the workpiece <NUM>. If, however, the workpiece <NUM> is outside of the predefined range of at least one of the sensors <NUM>, the motor <NUM> is prevented from activating or is deactivated. In at least one example, the sensors <NUM> prevent rotation of the sander <NUM> unless the sander <NUM> is in contact with a metal surface of the workpiece <NUM>.

In at least one example, the end effector <NUM> also includes a force compliance sub-system <NUM> that is configured to ensure that the sanding head <NUM> engages the workpiece <NUM> with predetermined force. The force compliance sub-system <NUM> provides linear and angular compliance in relation to the workpiece <NUM>, thereby allowing the sanding head <NUM> to comply with a surface (whether flat or arcuate) of the workpiece <NUM> and maintain a predetermined threshold force on the surface. The force compliance sub-system <NUM> also causes the sanding head <NUM> to maintain a predefined nominal pressure in relation to the workpiece <NUM>. As described herein, the force compliance sub-system <NUM> includes rods, ball joints, linear bearings, and springs, which cooperate to allow the sanding head <NUM> to angularly and linearly comply and conform with respect to variable surfaces (such as flat, curved, and the like) surfaces of the workpiece <NUM>.

For example, the force compliance sub-system <NUM> incudes a plurality of rods <NUM> coupled to the sanding head <NUM>. The rods <NUM> include first ends slidably coupled to linear bearings, such as linear slides <NUM>, and second ends coupled to the sanding head <NUM> (such as coupled to the collar <NUM>). Springs <NUM> (for example, compression springs) are secured around the rods <NUM> and are compressed between the sanding head <NUM> and another portion of the end effector <NUM>, such as a portion of a housing. The springs <NUM> (for example, compression springs) are configured to exert a desired linear force into the sanding head <NUM>, thereby ensuring that the sander <NUM> exerts the desired linear force into the workpiece <NUM>. The rods <NUM> linearly slide into and out from the linear slides <NUM> based on the shape of the workpiece <NUM> as the sanding head <NUM> moves thereover. As such, the rods <NUM> cooperate with the linear slides <NUM> and the springs <NUM> to provide linear force compliance with the workpiece <NUM> (in contrast to pneumatic actuators).

The force compliance sub-system <NUM> also includes ball joints <NUM> coupled to the second ends of the rods <NUM>. The ball joints <NUM> allow the sanding head <NUM> to radially pivot. In this manner (as shown in <FIG>, for example) the ball joints <NUM> cooperate with the rods <NUM> to provide angular force compliance with the workpiece <NUM> (in contrast to pneumatic actuators).

The springs <NUM> are selected to have a desired spring force constant. As such, the springs <NUM> ensure that the sanding head <NUM> maintains a desired threshold force with the surface of the workpiece <NUM>.

Alternatively, instead of (or in addition to) the rods <NUM>, slides, springs <NUM>, and ball joints, the force compliance sub-system <NUM> may include various other structures and mechanisms. For instance, other compliance mechanism are possible to ensure that the sanding head <NUM> provide force compliance with the workpiece <NUM>. For example, a known compliance mechanism that may be included in the force compliance sub-system <NUM> includes a gimbal and four bar linkage. Alternatively, the end effector <NUM> may not include the force compliance sub-system <NUM>.

In at least one example, in contrast to known methods that typically require manual dispensing of cleaning fluids, the end effector <NUM> also includes a fluid delivery sub-system <NUM> that is configured to dispense cleaning fluid onto the sander <NUM> and/or the workpiece <NUM>. The fluid delivery sub-system <NUM> is onboard the end effector <NUM>. As such, the fluid delivery sub-system <NUM> allows for automatic dispensing of cleaning fluid with no manual intervention. Further, the fluid delivery sub-system <NUM> onboard the end effector <NUM> leads to less fluid waste, less cleaning, and less purging, as compared to tubing that would typically supply fluid along the arm <NUM>.

The fluid delivery sub-system <NUM> includes a first fluid container <NUM> that retains a cleaning agent <NUM>, such as a liquid soap, detergent, solvent, and/or the like. The fluid delivery sub-system <NUM> also includes a second fluid container <NUM> that retains a mixing fluid, such as water <NUM>. The first fluid container <NUM> and the second fluid container <NUM> are fluidly coupled to a mixing chamber <NUM>, such as through a first fluid delivery line <NUM> (such as a first flexible tube), and a second fluid delivery line <NUM> (such as a second flexible tube), respectively. The mixing chamber <NUM> is also fluidly coupled to a fluid outlet <NUM> (such as a nozzle).

One or more pumps <NUM> (such as peristaltic pumps) are operatively coupled to the first fluid container <NUM>, the second fluid container <NUM>, and/or the mixing chamber <NUM>. The one or more pumps <NUM> operate to pump the cleaning agent <NUM> and the water <NUM> to the mixing chamber <NUM>, where the cleaning agent <NUM> and the water <NUM> are mixed into a predefined ratio (such as a water to cleaning agent ratio of <NUM>:<NUM>), and the combined, mixed fluid (that is, the cleaning agent <NUM> and the water <NUM> mixed into the predefined ratio) is dispensed out through the fluid outlet <NUM> and onto the sander <NUM> and/or the workpiece <NUM>. In this manner, the sander <NUM> may also be used to clean the workpiece <NUM> as the sander <NUM> is moved thereover. The one or more pumps <NUM> operate to dispense the combined, mixed fluid (that is, the cleaning fluid <NUM>) onto the workpiece <NUM>. Further, the one or more pumps <NUM> move the fluids through the fluid delivery sub-system <NUM>, thereby eliminating, minimizing, or otherwise reducing the need for cleaning and purging tubing. Alternatively, the end effector <NUM> may not include the fluid delivery sub-system <NUM>.

As described, the cleaning agent <NUM> and the water <NUM> are combined in the mixing chamber <NUM> to form a cleaning fluid <NUM>, which is the cleaning agent <NUM> and the water combined together at a desired ratio. The cleaning fluid <NUM> is dispensed out of the fluid outlet. The one or more pumps <NUM> are operatively coupled to the first fluid container <NUM>, the second fluid container <NUM>, and/or the mixing chamber <NUM>. The one or more pumps <NUM> are configured to pump the cleaning agent <NUM> and the water <NUM> to the mixing chamber <NUM>, and the cleaning fluid <NUM> out of the fluid outlet <NUM> onto one or both of the sander <NUM> and/or the workpiece <NUM>.

In at least one example, a control unit <NUM> is configured to control operation of the robotic sanding system <NUM>. The control unit <NUM> may be contained within the end effector <NUM>, for example. In at least one other example, the control unit <NUM> may be remotely located from the end effector <NUM>. For example, the control unit <NUM> may be part of a computer workstation that is in communication with various components of the robotic sanding system <NUM>, such as through one or more wired or wireless connections.

The control unit <NUM> is in communication with the actuator <NUM>, such as through one or more wired or wireless connections. The control unit <NUM> is configured to operate the actuator <NUM> to operate the arm(s) <NUM>. For example, the control unit <NUM> operates the actuator <NUM> to move the end effector <NUM> in relation to the workpiece <NUM> so that the sander <NUM> abuts against the workpiece <NUM>.

In at least one example, the control unit <NUM> is also in communication with the motor <NUM>, such as through one or more wired or wireless connections. As such, the control unit <NUM> may be configured to be operate the motor <NUM>.

The control unit <NUM> may also be in communication with the sensors <NUM>, such as through one or more wired or wireless connections. The control unit <NUM> may receive detection signals output by the sensors <NUM>. The detection signals indicate whether or not the workpiece <NUM> is in the predefined range of the sensors <NUM>. As such, the control unit <NUM> may operate the motor <NUM> based on the received detection signals. If all of the detection signals indicate that the workpiece <NUM> is within the predefined range, the control unit <NUM> may activate or maintain activation of the motor <NUM> so that the sander <NUM> operates on the workpiece <NUM>. If, however, at least one of the detection signals indicates that the workpiece <NUM> is outside of the predefined range (that is, the sensors <NUM> do not detect metal), the control unit <NUM> may deactivate or prevent activation of the motor <NUM>. Alternatively, the control unit <NUM> may not be in communication with the motor <NUM>. Instead, the sensors <NUM> may be operatively coupled to the motor <NUM> through one or more relays or other such components, as described above.

The control unit <NUM> may also be in communication with the one or more pumps <NUM>, such as through one or more wired or wireless connections. The control unit <NUM> may operate the one or more pumps <NUM> to dispense the combined cleaning fluid onto the sander <NUM>, the brushes <NUM>, and/or the workpiece <NUM>.

<FIG> illustrates a flow chart of a robotic sanding method, according to an example of the present disclosure. Referring to <FIG> and <FIG>, in operation, the actuator <NUM> is controlled (such as through the control unit <NUM>) to move the end effector <NUM> via the arm(s) <NUM> so that the sander <NUM> is moved onto and over the workpiece <NUM> at <NUM>. For example, at <NUM>, the end effector <NUM> is moved to move the sander <NUM> on and over a surface of the workpiece <NUM>.

At <NUM>, it is determined if the surface of the workpiece <NUM> is within the predefined range of the sensors <NUM>. If the surface is not within the predefined range of one or more of the sensors <NUM>, the method proceeds from <NUM> to <NUM>, at which activation of the motor <NUM> is prevented. If, however, the surface is within the predefined range of the sensors <NUM>, the method proceed from <NUM> to <NUM>, at which the motor <NUM> is activated to rotate the sander <NUM> to sand the surface of the workpiece <NUM>.

At <NUM>, cleaning fluid (which is the cleaning agent <NUM> and the water <NUM> combined and mixed at the predefined ratio) is dispensed onto one or more of the sander <NUM>, the brushes <NUM>, and/or the surface of the workpiece <NUM> to sanitize or otherwise clean the surface of the workpiece <NUM> as it is being sanded. Alternatively, the method may not include <NUM>.

As the sander <NUM> is operated to sand the surface, it is determined at <NUM> if the surface of the workpiece <NUM> is still within the predefined range of the sensors <NUM>. If not, the method proceeds to <NUM>, at which the motor <NUM> is deactivated, and the method returns to <NUM>. If, however, the surface of the workpiece <NUM> is still within the predefined range of the sensors <NUM>, the method proceeds from <NUM> to <NUM>, at which the motor <NUM> remains activated so that the sander <NUM> continues to sand the surface of the workpiece <NUM>.

At <NUM>, it is determined if the sanding operation is complete. If not, the method returns to <NUM>. If, however, the sanding operation is complete, the method ends at <NUM>.

In some examples, the determination of whether the surface of the workpiece <NUM> is within the predefined range of the sensors <NUM> occurs before the end effector <NUM> is operated to move the sanding head <NUM> on and over a surface of the workpiece <NUM>. In this manner, inadvertent operation of the sanding head <NUM> (for example, when the sanding head <NUM> is not over the workpiece) can be avoided.

As used herein, the term "control unit," "central processing unit," "unit," "CPU," "computer," or the like can include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set computers (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuit or processor including hardware, software, or a combination thereof capable of executing the functions described herein. Such are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of such terms. For example, the control unit <NUM> can be or include one or more processors that are configured to control operation thereof, as described herein.

The control unit <NUM> is configured to execute a set of instructions that are stored in one or more data storage units or elements (such as one or more memories), in order to process data. For example, the control unit <NUM> can include or be coupled to one or more memories. The data storage units can also store data or other information as desired or needed. The data storage units can be in the form of an information source or a physical memory element within a processing machine. The one or more data storage units or elements can comprise volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. In other examples, the nonvolatile memory can comprise read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM), and/or flash memory and volatile memory can include random access memory (RAM), which can act as external cache memory. The data stores of the disclosed systems and methods is intended to comprise, without being limited to, these and any other suitable types of memory.

The set of instructions can include various commands that instruct the control unit <NUM> as a processing machine to perform specific operations such as the methods and processes of the various examples of the subject matter described herein. The set of instructions can be in the form of a software program. The software can be in various forms such as system software or application software. Further, the software can be in the form of a collection of separate programs, a program subset within a larger program or a portion of a program. The software can also include modular programming in the form of object-oriented programming. The processing of input data by the processing machine can be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine.

The diagrams of examples herein can illustrate one or more control or processing units, such as the control unit <NUM>. It is to be understood that the processing or control units can represent circuits, circuitry, or portions thereof that can be implemented as hardware with associated instructions (e.g., software stored on a tangible and non-transitory computer readable storage medium, such as a computer hard drive, ROM, RAM, or the like) that perform the operations described herein. The hardware can include state machine circuitry hardwired to perform the functions described herein. Optionally, the hardware can include electronic circuits that include and/or are connected to one or more logic-based devices, such as microprocessors, processors, controllers, or the like. Optionally, the control unit <NUM> can represent processing circuitry such as one or more of a field programmable gate array (FPGA), application specific integrated circuit (ASIC), microprocessor(s), and/or the like. The circuits in various examples can be configured to execute one or more algorithms to perform functions described herein. The one or more algorithms can include features of examples disclosed herein, whether or not expressly identified in a flowchart or a method.

<FIG> illustrates a perspective lateral view of the robotic sanding system <NUM> operating on the workpiece <NUM>, according to an example of the present disclosure. The end effector <NUM> is secured to a distal end <NUM> of the arm <NUM>. The arm <NUM> is operated to move the sanding head <NUM> onto a surface <NUM> of the workpiece <NUM>.

<FIG> illustrates a perspective lateral view of the end effector <NUM>, according to an example of the present disclosure. The end effector <NUM> includes a housing <NUM>, such as one or more brackets, walls, beams, and/or the like. The housing <NUM> includes a first end <NUM> secured to the coupler <NUM>, and a second end <NUM> secured to the sanding head <NUM>. The coupler <NUM> removably secures to the attachment interface <NUM> of the arm <NUM> (shown in <FIG>).

In at least one example, the sanding head <NUM> includes or is coupled to a support plate <NUM>, which may be part of, or is otherwise connected to, the collar <NUM>. The motor <NUM> is secured to the support plate <NUM> and is operatively coupled to the sander <NUM>. The brushes <NUM> may overlay the sander <NUM>. Optionally, the brushes <NUM> may secure around a circumference of the sander <NUM>.

The force compliance sub-system <NUM> includes the rods <NUM> having first ends <NUM> slidably retained within linear slides <NUM> secured to the housing <NUM>, and second ends <NUM> coupled to the ball joints <NUM> that are rotatably coupled to the support plate <NUM>. The springs <NUM> are secured around the rods <NUM> and are compressed between the housing <NUM> and the ball joints <NUM> (or optionally the support plate <NUM>). Accordingly, the springs <NUM> exert a linear resistive force into the sanding head <NUM> that urges the sanding head <NUM> linearly in the direction of arrow A, thereby ensuring linear force compliance with the workpiece <NUM> (shown in <FIG> and <FIG>). The ball joints <NUM> allow the sanding head <NUM> to pivot thereabout. As such, the ball joints <NUM> ensure angular force compliance with the workpiece <NUM>. As shown, the force compliance sub-system <NUM> may include three rods <NUM>, three springs <NUM>, and three ball joints <NUM>. Optionally, the force compliance sub-system <NUM> may include less or more than three rods <NUM>, springs <NUM>, and ball joints <NUM> (such as one, two, four, or five rods <NUM>, springs <NUM>, and ball joints).

The first fluid container <NUM> and the second fluid container <NUM> are secured to the housing <NUM>. For example, the first fluid container <NUM> and the second fluid container <NUM> may be secured to the housing <NUM> such as through clamps, adhesives, fasteners, and/or the like. In other examples, the first fluid container <NUM> and the second fluid container <NUM> may be disposed within an internal chamber of the housing <NUM>.

A central longitudinal axis <NUM> of the motor <NUM> is not coaxial with a central longitudinal axis <NUM> of the coupler <NUM>. As such, the end effector <NUM> secures to the arm <NUM> at a different orientation than which the motor <NUM> rotates the sander <NUM>. As shown in <FIG>, the central longitudinal axis <NUM> may be orthogonal to the central longitudinal axis <NUM>. In at least one example, the central longitudinal axis <NUM> is the rotation axis about which the sander <NUM> rotates.

The sensors <NUM> may be coupled around lateral surfaces of the collar <NUM>. For example, the end effector <NUM> may include three or more sensors <NUM> secured to an outer circumference of the collar <NUM> at regular intervals. Optionally, the sensors <NUM> may be secured to lower surfaces of the collar <NUM>, and/or the support plate <NUM>. In other examples, the end effector <NUM> may include less or more than three sensors <NUM>.

<FIG> illustrates a perspective lateral view of an end effector <NUM>, according to an example of the present disclosure. The end effector <NUM> may differ in size, shape, and/or configuration than the end effector <NUM> shown in <FIG>. As shown in <FIG>, the housing <NUM> may include a plurality of walls <NUM> that contain various components of the end effector <NUM>.

In the example shown in <FIG>, the coupler <NUM> is mounted on a top surface <NUM> of a first end <NUM> of the end effector <NUM>, and the sanding head <NUM> extends from a lower surface <NUM> of a second end <NUM> (opposite from the first end <NUM>) of the end effector <NUM>. As such, the central longitudinal axis <NUM> of the motor <NUM> is separated and offset from the central longitudinal axis <NUM> of the coupler <NUM>. As shown in <FIG>, the central longitudinal axis <NUM> and the central longitudinal axis <NUM>, while separate and offset from one another, may be parallel. For example, the central longitudinal axis <NUM> may be separated from the central longitudinal axis <NUM> by <NUM> or less, such as <NUM> or less, or <NUM> (<NUM> inches or less, such as <NUM> inches or less, or <NUM> inches). Optionally, the central longitudinal axis <NUM> may be separated from the central longitudinal axis <NUM> by a distance greater than <NUM> (<NUM> inches). The offset configuration improves the reach of the sanding head <NUM> and allows for improved ability to place the center of the sander <NUM> at a desired location. In at least one example, the central longitudinal axis <NUM> is the rotation axis about which the sander <NUM> rotates.

The configuration shown in <FIG>, in which the sanding head <NUM> and the coupler <NUM> are at opposite ends of the end effector <NUM>, provide a more mobile and manipulatable sanding head <NUM>. For example, the end effector <NUM> may be pivoted and rotated about the central longitudinal axis <NUM> to allow the sanding head <NUM> to be swung into confined spaces that may not otherwise be large enough to accommodate a sanding head that is coupled to a motor that is coaxial with a coupler. In this manner, examples of the present disclosure provide an end effector <NUM> that is configured to efficiently and effectively operate on complex surfaces.

<FIG> illustrates a perspective lateral view of the housing <NUM> and the collar <NUM>, according to an example of the present disclosure. The housing <NUM> and the collar <NUM> may be formed of plastic, for example. In at least one example, the housing <NUM> and the collar <NUM> may be formed through three-dimensional (3D) printing. The printed housing <NUM> and the collar <NUM> reduce overall weight of the end effector <NUM> (in contrast to metal structures). Optionally, the housing <NUM> and the collar <NUM> may be formed of metal.

<FIG> illustrates a flow chart of a robotic sanding method, according to an example of the present disclosure. Referring to <FIG> and <FIG>, the robotic sanding method includes, at <NUM>, providing the end effector <NUM> with the sanding head <NUM> including the sander <NUM> configured to sand a surface of the workpiece <NUM>. The robotic sanding method also includes, at <NUM>, operatively coupling the electric motor <NUM> to the sander <NUM> within the end effector <NUM>. The electric motor <NUM> includes the first central longitudinal axis <NUM>. The robotic sanding method also include, at <NUM>, removably securing the coupler <NUM> of the end effector <NUM> to the attachment interface <NUM> of an arm <NUM> of the robotic sanding system <NUM>. The coupler <NUM> includes the second central longitudinal axis <NUM>. The robotic sanding method also includes, at <NUM>, offsetting the first central longitudinal axis <NUM> from the second central longitudinal axis <NUM>. The robotic sanding method also includes, at <NUM>, coupling the one or more sensors <NUM> to the sanding head <NUM>. The one or more sensors <NUM> are configured to detect presence of metal within a predefined range. The robotic sanding method also includes, at <NUM>, preventing activation of the electric motor <NUM> in response to the metal being outside of the predefined range.

In some examples, the steps of the robotic sanding method illustrated in <FIG> are carried out by an end effector, such as the end effector <NUM>. In some examples, the steps of the robotic sanding method illustrated in <FIG> are carried out by the end effector <NUM>, where the motor <NUM> is an electric motor.

In some examples, the robotic sanding method also includes providing the sanding head <NUM> with one or more brushes <NUM> configured to capture one or more of debris or cleaning fluid.

In some examples, the robotic sanding method also includes ensuring, by the force compliance sub-system <NUM>, that the sanding head <NUM> engages the workpiece <NUM> with a predetermined force.

In some examples, the robotic sanding method also includes dispensing, by the fluid delivery sub-system <NUM>, cleaning fluid <NUM> onto one or both of the sander <NUM> or the workpiece <NUM>. In some examples, said dispensing includes retaining the cleaning agent <NUM> within the first fluid container <NUM>; retaining water <NUM> within the second fluid container <NUM>; fluidly coupling the mixing chamber <NUM> to the first fluid container <NUM> and the second fluid container <NUM>; combining the cleaning agent <NUM> and the water <NUM> in the mixing chamber <NUM> to form the cleaning fluid <NUM>; coupling the fluid outlet <NUM> to the mixing chamber <NUM>; and dispensing the cleaning fluid <NUM> out of the fluid outlet <NUM>. In some examples, said dispensing also includes operatively coupling the one or more pumps <NUM> to one or more of the first fluid container <NUM>, the second fluid container <NUM>, or the mixing chamber <NUM>; and pumping, by the one or more pumps <NUM>, the cleaning agent <NUM> and the water <NUM> to the mixing chamber <NUM>, and the cleaning fluid <NUM> out of the fluid outlet <NUM> onto one or both of the sander <NUM> or the workpiece <NUM>.

As described herein, examples of the present disclosure provide robotic sanding systems having increased mobility and increased range. Moreover, examples of the present disclosure provide robotic sanding systems having end effectors that are able to operate in confined spaces and areas.

It is to be understood that the above description is intended to be illustrative, and not restrictive. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the various examples of the disclosure. While the dimensions and types of materials described herein are intended to define the parameters of the various examples of the disclosure, the examples are by no means limiting. Many other examples will be apparent to those of skill in the art upon reviewing the above description. In the appended claims and the detailed description herein, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein. " Moreover, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

Claim 1:
An end effector (<NUM>) for a robotic sanding system (<NUM>), the end effector (<NUM>) comprising:
a sanding head (<NUM>) including a sander (<NUM>);
an electric motor (<NUM>) operatively coupled to the sander (<NUM>) and contained within the end effector (<NUM>), wherein the motor (<NUM>) is configured to rotate the sander (<NUM>); and
one or more sensors (<NUM>) coupled to the sanding head (<NUM>), wherein
the one or more sensors (<NUM>) are configured to detect presence of a metal within a predefined distance; and
the motor (<NUM>) is configured to be prevented from activation in response to the metal being outside of the predefined distance.