Robotic arm with roll reorientation mechanism and grapple mechanism

Abstract

To provide a novel robotic arm that is light, stowable and having fewer active degrees of freedom for payload manipulation.SOLUTION: A robotic arm includes a mechanical arm assembly having booms connected by actively driven joints to provide pitch and yaw control at a shoulder, elbow and wrist of the arm. Force moment sensors and / or actuators for active roll and / or yaw control at an end of the arm are omitted. An orienting mechanism provides a grapple mechanism with passive pitch and yaw control to pivot the grapple mechanism to grasp a payload without having to actively position the end effector to align with an axis of the payload. Prior to lifting the payload, a grapple fixture is rigidized by fully retracting the grapple mechanism.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The embodiments disclosed herein relate to a robotic arm for lifting objects, and in particular to a robotic arm with passive and active orientation mechanisms and a grapple mechanism for payload manipulation. [Background technology]

[0002] Remotely operated robotic arms have numerous applications on Earth, in space, and on celestial bodies. In space applications, robotic arms are typically mounted on vehicles (e.g., spacecraft, space stations, rovers) to perform a variety of tasks. As an example, a robotic arm on a space station may be used to grasp a payload (e.g., a cargo module) in orbit. Another example is the use of a robotic arm on a rovers to pick up and transfer a payload (e.g., regolith samples) on the lunar surface.

[0003] Mass is an important consideration when designing a robotic arm for space applications, because the arm and the vehicle it is attached to must be launched into orbit: to put a heavier payload into orbit, more fuel must be carried, further increasing the overall mass.

[0004] Another consideration is the range of movement possible for the robot arm, which is expressed as the degrees of freedom (pitch, roll, yaw) of the arm. It may be desirable to have a robot arm capable of at least six degrees of freedom (i.e., capable of movement in all X, Y, Z directions), but more degrees of freedom require more components to drive the pitch, roll, and yaw of the robot arm, thus increasing the cost, weight, and complexity of the arm.

[0005] Another challenge is managing the loads placed on the payload when it is manipulated by a robotic arm. Typically, a robotic arm includes force moment sensors (i.e., tactile sensors) that measure the forces placed on the payload. However, sensors also add weight and complexity.

[0006] Size is an additional consideration. Cargo space within a spacecraft or launch vehicle is limited. Thus, robotic arms for space applications, such as the Canadarm®, are built with articulatable sections that can be packed together into a stowed configuration for orbit. However, the stowed interface of the arm can ultimately constrain the arm's degrees of freedom. Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, there is a need for novel robotic arms for Earth and space applications that are lightweight, stowable, and have fewer active degrees of freedom for payload manipulation. [Means for solving the problem]

[0008] A robotic arm is provided with passive and active orientation mechanisms and a grapple mechanism for payload manipulation.

[0009] According to some embodiments, there is a robotic arm for manipulating a payload. The robotic arm includes a mechanical arm assembly and an end effector. The mechanical arm assembly includes a boom connected by an active drive joint. The active drive joint provides the robotic arm with at least three degrees of freedom.

[0010] The end effector includes an actively driven grapple mechanism for gripping a payload and an orientation mechanism for providing the grapple mechanism with pitch, yaw, and rear driven roll degrees of freedom.

[0011] The grapple mechanism includes a linear drive system and at least two claws for grasping a payload, each claw including a linkage to the linear drive system that translates linear motion from the drive system to extend or retract each claw.

[0012] The orientation mechanism includes a revolute joint connected to the grapple mechanism for providing passive pitch and yaw to the grapple mechanism, and a pressure plate assembly for providing a rear driven roll degree of freedom to the end effector.

[0013] According to one embodiment, there is a method of manipulating a payload with a robotic arm, the method including manipulating the robotic arm to a ready-to-approach state position relative to a payload, manipulating the robotic arm to hover above the payload, setting a state of an end-effector grabble mechanism to capture the payload, manipulating the end-effector grabble mechanism to capture the payload, performing a soft capture of the payload, rigidifying the payload, and lifting the payload from a current position.

[0014] The method may further include deploying the robot arm from the compact configuration and performing an inspection activity to prepare for operation. The method may further include operating the robot arm to hold a rigidified payload against a roll post, operating the robot arm to press the payload against the roll post and reorient the payload, verifying alignment of the reoriented payload, and rigidifying the reoriented payload. The method may further include operating the robot arm holding the rigidified payload to hover above a surface, de-rigidifying the payload, lowering the payload onto the surface, and releasing the payload. The method may further include storing the robot arm and stowing the robot arm to the compact configuration.

[0015] Other aspects and features will become apparent to those of ordinary skill in the art upon review of the following description of several exemplary embodiments.

[0016] The drawings accompanying this specification are intended to illustrate various examples of the articles, methods, and devices herein. The drawings are not to scale and are for illustrative purposes only. [Brief description of the drawings]

[0017] [Figure 1] 1 is a flow diagram of a method for manipulating a payload with a robotic arm, according to an embodiment. [Figure 2A] FIG. 2 is a diagram of a robotic arm, according to one embodiment. [Figure 2B] FIG. 2 is a diagram of an end effector, according to an embodiment. [Figure 2C] FIG. 2 is a diagram of an end effector, according to an embodiment. [Figure 2D] FIG. 2 is a diagram of an end effector, according to an embodiment. [Figure 2E] FIG. 2 is a diagram of an end effector, according to an embodiment. [Diagram 3] FIG. 2 is a diagram of an end effector, according to an embodiment. [Figure 4] 1 is a flow diagram of a method for picking up a payload by a robotic arm, according to an embodiment. [Figure 5A] 5A-5C illustrate steps of the method of FIG. 4 performed by a robotic arm. [Figure 5B] 5A-5C illustrate steps of the method of FIG. 4 performed by a robotic arm. [Figure 5C] 5A-5C illustrate steps of the method of FIG. 4 performed by a robotic arm. [Figure 6A] 5 illustrates steps of the method of FIG. 4 performed by an end effector. [Figure 6B] 5 illustrates steps of the method of FIG. 4 performed by an end effector. [Figure 6C] 5 illustrates steps of the method of FIG. 4 performed by an end effector. [Figure 6D] 5 illustrates steps of the method of FIG. 4 performed by an end effector. [Figure 7] 1 is a flow diagram of a method for placing a payload with a robotic arm, according to an embodiment. [Figure 8A] 8A-8D illustrate steps of the method of FIG. 7 performed by a robotic arm. [Figure 8B] 8A-8D illustrate steps of the method of FIG. 7 performed by a robotic arm. [Figure 8C] 8A-8D illustrate steps of the method of FIG. 7 performed by a robotic arm. [Figure 8D] 8A-8D illustrate steps of the method of FIG. 7 performed by a robotic arm. [Figure 8E] 8A-8D illustrate steps of the method of FIG. 7 performed by a robotic arm. [Figure 9A] 8A-8D illustrate steps of the method of FIG. 7 performed by an end effector. [Figure 9B]8A-8D illustrate steps of the method of FIG. 7 performed by an end effector. [Figure 9C] 8A-8D illustrate steps of the method of FIG. 7 performed by an end effector. [Figure 9D] 8A-8D illustrate steps of the method of FIG. 7 performed by an end effector. [Figure 10] 1 is a flow diagram of a method for reorienting a payload by a robotic arm, according to an embodiment. [Figure 11A] 11A-11C illustrate steps of the method of FIG. 10 performed by a robotic arm. [Figure 11B] 11A-11C illustrate steps of the method of FIG. 10 performed by a robotic arm. [Figure 12A] 11A-11C illustrate steps of the method of FIG. 10 performed by an end effector. [Figure 12B] 11A-11C illustrate steps of the method of FIG. 10 performed by an end effector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Robotic arm apparatus and methods for manipulating payloads are described below to provide examples of each of the claimed embodiments. The robotic arm apparatus and methods disclosed herein are generally for implementation on celestial bodies (e.g., the Moon or Mars) or for orbital applications. The embodiments described below do not limit any claimed embodiment, and any claimed embodiment may be directed to methods and apparatuses different from those described below. The claimed embodiments are not limited to an apparatus or method having all of the features of any one apparatus or method described below, or to features common to multiple or all of the apparatuses described below.

[0019] Referring to FIG. 1, there is shown a flow diagram of a method 10 of manipulating a payload with a robotic arm. The method 10 may be performed for multiple tasks, including picking up payloads from a rover deck and placing them on the lunar surface or vice versa; retrieving payloads from a storage location such as a lander or station and placing them on the rover deck for transport; connecting a trailer to a towing vehicle; picking up tools (e.g., cameras, instruments, drills); and collecting lunar samples. The method 10 includes three general steps 12, 14, 16 that are common to all of the tasks for which the method 10 is performed. Each step 12, 14, 16 is shown in FIG. 4, FIG. 7, and FIG. 10 and may include sub-methods described below.

[0020] Briefly, at 12, the robotic arm picks up a payload. The arm includes an end effector with a grapple mechanism for gripping the payload. According to some embodiments, the end effector may be removable / replaceable. At 14, the arm reorients the payload. Reorienting generally means moving the robotic arm to change the position and / or orientation of the payload. At 16, the arm places the payload down, on a surface.

[0021] 2A, there is shown a diagram of a robotic arm 120 according to an embodiment. The arm 120 includes a mechanical arm assembly 124 and an end effector 126 for gripping a payload 150. The robotic arm 120 includes an arm-to-host interface 118 that physically, mechanically, and electrically connects the robotic arm 120 to a host structure such as a vehicle 122 (e.g., a planetary rover) or a platform such as a lander deck. An arm-to-end effector interface 119 physically and electrically connects the mechanical arm assembly 124 to the end effector 126. At least one camera (not shown) is disposed on the arm (e.g., on the interface 119) to view the end effector 126 and the payload 150.

[0022] The mechanical arm assembly 124 includes booms 110, 111 connected by actively driven joints 113, 114, 115, 116, including shoulder pitch joint 113 and shoulder yaw joint 114, elbow pitch joint 115, and wrist pitch joint 116. The combined motion of the active joints 113, 114, 115, 116 provides the robotic arm 120 with four degrees of freedom (shoulder pitch, shoulder yaw, elbow pitch, and wrist pitch). The booms 110, 111 include tube links between the joints 114, 115, 116.

[0023] The tolerances and components of the robotic arm 120 are constructed to minimize mass and complexity while allowing the arm 120 to operate without maintenance in the harsh space and lunar environments when exposed to dust and temperatures from -120 to 50 degrees Celsius and radiation. The robotic arm 120, specifically the moving parts including the joints 113, 114, 115, 116 and the end effector 126 must be at least dust resistant. According to one embodiment, the joints 113, 114, 115, 116 and specifically the end effector 126 are sealed to protect against dust and overburden.

[0024] To reduce mass and complexity, force moment sensors (i.e., tactile sensors) typically used in robotic arms to sense forces applied to the payload 150 may be omitted. To further reduce mass toward the tip of the end effector 126 of the arm 120 and generally reduce loads on the shoulder, actuators for roll and / or yaw control at the tip may be omitted. For example, according to one embodiment, the elbow joint 115 and the wrist joint 116 do not have actuators that produce roll or yaw motion. These constraints create challenges in managing the loads applied to the payload 150 as it is picked up, manipulated, or set down. This is especially true when the payload 150 is picked up or set down in a confined space where the spatial extent constrains the degrees of freedom of the robotic arm 120. As described below, these challenges are mitigated by features of the end effector 126.

[0025] 2B-2E, there is shown a diagram of an end effector 100, according to one embodiment. The end effector 100 includes an actively driven grapple mechanism 102 for gripping a payload by a grapple fixture 155 attached to the payload (payload not shown in FIGS. 2B-2E), and an orienting mechanism 104 for orienting the grapple mechanism 102. The grapple mechanism 102 includes claws, jaws, etc. for gripping the grapple fixture 155 (and thus the payload).

[0026] The orienting mechanism 104 provides passive pitch and yaw degrees of freedom for the grapple mechanism 102 to pivot and grip the grapple fixture 155 without having to actively position the end effector 100 to align with the axis of the grapple fixture 155 (FIGS. 2B-2C). This allows for a "soft" capture of the grapple fixture 155 by the grapple mechanism 102 as the end effector 100 propels forward to reduce the effective retraction distance (FIG. 2D). Prior to lifting a payload, the grapple fixture 155 is rigidified by the end effector 100 by fully retracting the grapple mechanism 102 (FIG. 2E).

[0027] 3, there is shown a diagram of an end effector 200 according to one embodiment, which may be the end effector 126, 100 shown in Figures 2A and 2B-2E, respectively. The end effector 200 includes an actively driven grapple mechanism 202 for grasping a payload 250.

[0028] The payload 250 includes a grapple fixture 252 on an exterior surface of the payload 250. The grapple fixture 252 is not necessarily centered or aligned with the payload's center of mass. A range of acceptable center of gravity locations for the grapple fixture 252 may be defined for the payload 250. The grapple fixture 252 is preferably shaped to be grasped by the grapple mechanism 202. The grapple fixture 252 includes a contact surface 228 for contacting a corresponding contact surface 230 on the grapple mechanism 202.

[0029] The grapple mechanism 202 includes at least two claws 204 that close around a grapple fixture 252. Each claw 204 culminates in a curved tip 206. According to one embodiment, opening and closing of the claws 204 is driven by a motor 210 to actuate a linear drive system 212 (e.g., a ball screw, a lead screw, an acme screw, a linear actuator, etc.). Each claw 204 includes a linkage 208 (e.g., a four-bar linkage) to the linear drive system 212. In the illustrated embodiment, an extension link 215 transfers the linear motion of the screwdriver 212 to each claw 204 by rotating a driven link of the four-bar linkage 208. As the screw 212 rotates, a ball nut 217 connected to the extension link 215 moves axially (indicated by arrow 240), causing rotation of the four-bar linkage 208 and opening and closing the claws 204.

[0030] It should be noted that advantageously, only a rotary seal is required to seal the joint connection point 218 from dirt, rather than a linear seal, which would be more complicated to implement.

[0031] The motor 210 includes an angular position sensor for the motor and joint state position monitoring to estimate the position / state (i.e., open or closed) of the grapple mechanism 202. The grapple mechanism 202 may further include an end of travel switch that is triggered when the claws 204 are fully open and fully closed, respectively. According to another embodiment, the grapple mechanism 202 includes a home position switch and a motor resolver to estimate the position / state of the claws 204.

[0032] The end effector 200 includes an orientation mechanism 214. The orientation mechanism 214 includes a pressure plate assembly 220 to provide a roll degree of freedom for the end effector 200. The pressure plate assembly 220 includes a set of bearings 226 between an inner housing 222 that holds the grapple mechanism 202 and an outer housing (not shown) that mounts the end effector 200 to a mechanical arm. A spring-loaded friction disc 224 allows the friction of the pressure plate assembly 220 to be adjusted.

[0033] The friction at the friction disk-bearing interface must be sufficient to prevent undesired rotation of the end effector 200 under the action of the mass of the payload 250 when the center of gravity of the payload 250 is offset from the central axis of the end effector 200. However, the friction may not be so great to prevent the rearward driving roll degree of freedom of the end effector 200. Typically, the rearward driving roll degree of freedom of the end effector 200 in a clockwise or counterclockwise direction is achieved using a roll post (see FIGS. 11-12). Also, the roll travel is limited to a clockwise or counterclockwise direction to prevent continuous motion that may twist the cables of the end effector 200.

[0034] The orientation mechanism 214 includes an end of travel switch for monitoring clockwise or counterclockwise roll of the end effector 200. According to one embodiment, the orientation mechanism 214 includes a home position switch for estimating the roll position of the end effector 200. According to another embodiment, the end effector 200 includes a "return" feature for resetting the position of the end effector using a roll post.

[0035] The orientation mechanism 214 includes a passive wobble joint 216 to provide pitch and yaw (i.e., rotational degrees of freedom) compliance to the end effector 200 when driven backward by application of an external force to the held payload 250. Although the wobble joint 216 is depicted as a spherical joint, it does not have a roll degree of freedom. The wobble joint is sealed from dirt / soil by a flexible shielding seal 232.

[0036] Locking out / rigidifying the wobble joint 216 is accomplished by retracting / raising the claw 204 until the contact surface 228 of the payload contacts the contact surface 230 on the grapple mechanism 202 (see FIGS. 6C and 6D). The contact of the surfaces 228, 230 is matched with the contact of an inner hard catch (not shown) that aligns the wobble joint 216 such that both the grapple fixture 252 and the wobble joint 216 simultaneously align with the axis of the end effector 200 and are held rigidly in that position, locking out movement of the wobble joint 216. This prevents pitch and yaw of the payload 250 and rigidifies it relative to the grapple mechanism 202 / end effector 200.

[0037] Referring to Figure 4, there is shown a flow diagram of a method 300 for picking up a payload with a robotic arm, according to one embodiment. The method 300 may be implemented at step 12 of method 10 of Figure 1. Acts in the method 300 are displayed in Figures 5A-5C and 6A-6D. The method 300 may be implemented for a variety of tasks including transferring payloads from the deck of a planetary rover to the lunar surface (or vice versa), collecting lunar samples, and picking up equipment / tools.

[0038] At 302, the robotic arm is deployed from a stowed configuration. In the embodiment shown in Figure 5A, the robotic arm 420 is stowed within a vehicle 422 (e.g., in the cargo bay of a lander or rover) in a compact stowed configuration. In other embodiments, the robotic arm 420 is mounted to a platform on a non-vehicle host structure.

[0039] At 304 , the robotic arm 420 is manipulated into a ready position for a payload 450 .

[0040] At 306, the robotic arm 420 is manipulated such that the end effector 500 hovers above the payload 450 (FIGS. 5B and 6A). As shown in FIG. 6A, the end effector 500 and grapple mechanism 502 are generally positioned above the payload 550, but may not be centered relative to the payload 550 and / or the grapple fixture 552. That is, the end effector 500 and grapple mechanism 502 may be laterally and vertically offset from the axis of the grapple fixture 552.

[0041] At 308, the end effector grapple mechanism is set in a state ready to capture a payload (FIG. 6A). The claws 504 are extended to an open position in preparation for grasping a payload 550. The end effector 500 is moved by the robotic arm 524 to position a grapple fixture 552 between the open claws 504.

[0042] At 310, the grapple mechanism is operated to capture a payload. As shown in FIGURE 6B, the claws 504 are closed around the grapple fixture 552. When the closing claws 504 contact the grapple fixture 552, the orientation mechanism 514 of the end effector 500 provides passive pitch and yaw compliance to allow for an offset grasp of the grapple fixture 552 by the grapple mechanism 502. The pitch and yaw compliance also allows the payload 550 to be picked up from an inclined surface.

[0043] At 312, soft capture of the payload by the grapple mechanism is performed. As shown in FIGURE 6C, the end effector 500 thrusts, shortening the effective retraction distance of the grapple mechanism 502. As the end effector 500 thrusts, the claws 504 pull the grapple fixture 552 closer, bringing the respective contact surfaces on the grapple mechanism 502 and the grapple fixture 552 closer together.

[0044] At 314, the payload is rigidified. As shown in FIGURE 6D, when the respective contact surfaces on the grapple fixture 552 and the grapple mechanism 502 make contact, the claws 504 are retracted into a closed position which rigidifies the payload 550. This also locks out the orienting module 514 to fix the pitch and yaw of the payload 550.

[0045] At 316, the payload is lifted from its current position (FIG. 5C). The robotic arm 420 is articulated to lift the payload 450 from its current position.

[0046] Referring to Figure 7, there is shown a flow diagram of a method 320 for placing a payload by a robotic arm, according to one embodiment. The method 320 may be implemented in step 16 of method 10 of Figure 1. The actions of method 320 are depicted in Figures 8A-8E and 9A-9D. The method 320 may be implemented for a variety of tasks, including transferring payloads from the deck of a planetary rover to the lunar surface (or vice versa), collecting lunar samples, and picking up equipment / tools.

[0047] At 322, a robotic arm having an end effector holding a rigidified payload is manipulated to hover above a surface (FIGS. 8A, 9A). As shown in FIG. 8A, a robotic arm 420 may be mounted on a vehicle 422 (e.g., a lander or rover) and holds a rigidified payload 450 above a surface 460 (e.g., the lunar surface). As shown in FIG. 9A, the payload 550 is rigidified by an end effector 500. The claws 504 of the grapple mechanism 502 are retracted in a closed position around a grapple fixture 552. Contact between the grapple fixture 552 and the respective surfaces of the grapple mechanism 502 fixes the pitch and yaw compliance of the orienting mechanism 514.

[0048] At 324, the payload is de-rigidified (FIGS. 8B, 9B). As shown in FIG. 8B, when the payload 450 is de-rigidified, it is able to tilt and rotate (i.e., pitch and yaw) if it is not held rigidly by the robotic arm 420. As shown in FIG. 9B, the claws 504 of the grapple mechanism 502 partially spread out, allowing the grapple fixture 552 and the respective contact surfaces on the grapple mechanism 502 to separate, thereby de-rigidifying the payload 550 and releasing the orientation mechanism 514 to allow the payload 550 to pitch and yaw. It should be noted that when the payload 550 is de-rigidified, the claws 504 still have a firm grip on the grapple fixture 552 (and payload 550).

[0049] At 326, the payload is lowered onto the surface in a "let down stroke" (FIGS. 8C, 9C). As shown in FIG. 8C, the robot arm 420 is articulated for the let down stroke to precisely place the payload 450 on the surface 460. Robot arm 420 motion alone (without end effector motion) is used for most of the let down stroke.

[0050] 9C, the end effector 500 requires only the passive pitch and yaw degrees of freedom provided by the orienting module 514 to coordinate the final landing of the payload 550 on the surface 560. The passive pitch and yaw degrees of freedom allow the payload 550 to be gently lowered onto the sloping surface 560. Otherwise, the grapple mechanism 502 would require a degree of active travel to lower the payload 550 onto the slope, which would increase complexity. The grapple mechanism 502 also includes short-stroke compliant (spring travel) contact points with an indicator switch that registers when the payload 550 has landed on the surface 560.

[0051] At 328, the payload is released (FIGS. 8D, 9D). As shown in FIG. 9D, the claws 504 of the grapple fixture 502 are fully extended, releasing their hold on the grapple fixture 552.

[0052] At 330, the robotic arm is retracted. At 332, the robotic arm is stored in a compact configuration (FIG. 8E).

[0053] Referring to Figure 10, there is shown a flow diagram of a method 340 for reorienting a payload. The method 340 may be implemented at step 14 of method 10 of Figure 1. The method 340 may be implemented to reorient a payload for efficient storage or to fit a payload into a limited space. Certain operations in the method 340 are depicted in Figures 11A-11B and 12A-12B.

[0054] At 342, a robotic arm having an end effector holding a payload is manipulated relative to the roll post.

[0055] 11A, the payload 450 is not aligned with the edge 423 of the vehicle 422 (e.g., lander, rover) when held by the robotic arm 420. For efficient storage, the payload 450 must be rotated to be aligned with the edge 423. As described above, the robotic arm 420 does not have an actively driven wrist roll joint to rotate the payload 450. Instead, a roll post 470 disposed on the vehicle 422 proximate to the robotic arm 420 is provided to overcome the limitations of the degrees of freedom of the robotic arm 420 and align the payload 450 with the edge 423 for efficient storage.

[0056] At 344, the robotic arm is manipulated to press the payload against the roll post and reorient the payload. As shown in FIG. 12A, the orientation mechanism 514 provides a passive roll degree of freedom for the end effector 500. As the robotic arm 524 presses the edge of the payload 550 against the roll post 570, the end effector 500 holding the payload 550 can be driven backwards.

[0057] A sufficient amount of rearward drive torque is required to overcome friction within the orientation mechanism 514 that prevents roll due to gravity of the payload 550. That is, the payload 550 will roll only if there is sufficient rearward drive torque applied by the robot arm 524 and roll post 570. For example, if the robot arm 524 moves with sufficient force in the direction of arrow 572, the end effector 500 and payload 550 will rotate in the direction of arrow 574.

[0058] At 346, the alignment of the reoriented payload is verified. As shown in FIGURE 12B, payload 550 includes fiducial markings 554 around a grapple fixture 552 on the top of payload 550. The markings 554 are visible to a camera (not shown) on the robotic arm and are used to determine when the target payload roll angle has been achieved. If payload alignment is inaccurate, the method 340 returns to step 344 until accurate alignment is achieved.

[0059] At 348, the payload is rigidified by the end effector.

[0060] Although the above description provides one or more example devices, methods, or systems, it will be understood that other devices, methods, or systems may fall within the scope of the claims as interpreted by one of ordinary skill in the art. [Explanation of symbols]

[0061] 10, 300, 320, 340 methods 100, 126, 200, 500 End Effector 102, 202 Actively driven grapple mechanism 104, 214 Orientation mechanism 110, 111 Boom 113 Actively actuated joint, shoulder pitch joint 114 Actively actuated joint, shoulder-joint 115 Actively driven joint, elbow pitch joint 116 Actively driven joint, wrist pitch joint 118 Arm-host connection surface 119 Arm-end effector connection surface 120, 420, 524 Robot Arm 122, 422 vehicles 124 Mechanical Arm Assembly 150, 250, 450, 550 Payload 155, 252, 552 Grapple Fixture 204, 504 Claw 206 (of a claw) curved tip 208 Link mechanism, 4-bar link mechanism 210 Motor 212 Linear drive system, screwdriver, screw 215 Extension Link 216 Passive Wobble Joint 217 Ball nut 218 Joint connection point 220 Pressure Plate Assembly 222 Inner Housing 224 Spring-loaded friction disk 226 Bearings 228 (Payload) Contact Surface, Payload Contact Surface 230 (Grapple Mechanism) Contact Surface 232 Flexible shielding seal 240, 572, 574 Arrows 423 (Vehicle) Edge 460, 560 surface 470, 570 roll post 502 Grapple Mechanism 514 Orientation mechanism, orientation module 554 Reference Mark

Claims

1. an actively driven grapple mechanism for grasping a payload; an orientation mechanism for providing the grapple mechanism with pitch, yaw, and rear drive roll degrees of freedom; An end effector for a robotic arm.

2. The grapple mechanism includes: A linear drive system; at least two claws for gripping the payload, each claw including a linkage to the linear drive system; Including, The linkage translates linear motion from the drive system to extend or retract each claw. The end effector of claim 1 .

3. The alignment mechanism is a rotary joint connected to the grapple mechanism for providing passive pitch and yaw to the grapple mechanism; a pressure plate assembly for providing a rear drive roll degree of freedom for the end effector; The end effector of claim 1 , comprising:

4. The end effector of claim 3 , wherein the rotary joint and the pressure plate assembly are sealed to protect against dust.

5. The grapple mechanism includes: A ball screw driven by a motor; at least two claws for gripping the payload, each claw including a four-bar linkage and an extension link connected to the ball screw; Including, The extension link transmits the linear motion of the ball screw to rotate the driven link of the four-bar linkage to extend or retract each claw. The end effector of claim 1 .

6. a mechanical arm assembly including a boom connected by an active drive joint, the active drive joint providing at least three degrees of freedom to the robotic arm; An end effector according to any one of claims 1 to 5; a robotic arm.

7. The grapple mechanism is A ball screw driven by a motor; at least two claws for gripping a payload, each claw including a four-bar linkage and an extension link connected to the ball screw; Including, The extension link transmits the linear motion of the ball screw to rotate the driven link of the four-bar linkage to extend or retract each claw.

7. A robotic arm according to claim 6.

8. The robotic arm of claim 6 , wherein the actively driven joint is sealed to protect against dust.

9. The robotic arm of claim 6 , further comprising at least one camera positioned to view the end effector and payload.

10. 1. A method for manipulating a payload with a robotic arm, comprising: maneuvering the robotic arm to an approach ready position relative to the payload; manipulating the robotic arm to hover above the payload; setting a state of an end effector grabble mechanism to capture the payload; operating the end effector grabble mechanism to capture the payload; performing a soft capture of the payload; rigidifying the payload; lifting the payload from its current position; A method comprising:

11. deploying the robotic arm from a compact configuration; conducting inspection activities to prepare for operation; The method of claim 10 further comprising:

12. manipulating the robotic arm to hold the rigidified payload against a roll post; manipulating the robotic arm to press the payload against the roll post and reorient the payload; verifying the alignment of the redirected payload; rigidifying the reoriented payload; The method of claim 11 further comprising:

13. manipulating the robotic arm holding the rigidified payload to hover above a surface; de-rigidifying the payload; lowering the payload onto the surface; releasing the payload; The method of claim 11 further comprising:

14. storing the robotic arm; stowing the robot arm into a compact configuration; The method of claim 13 further comprising:

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