Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J13/00—Controls for manipulators
  • B25J13/08—Controls for manipulators by means of sensing devices, e.g. viewing or touching devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J15/00—Gripping heads and other end effectors
  • B25J15/08—Gripping heads and other end effectors having finger members

Definitions

• This disclosure relates to a robotic hand with multiple fingers.
• Robot hands equipped with multiple fingers are known (see, for example, Patent Documents 1 and 2).
• a robot hand In order for a robot hand to stably grasp a variety of objects, it is desirable to be able to select an appropriate gripping form depending on the object.
• a robot hand includes a first finger configured to be capable of performing a gripping motion on an object, and a second finger configured to be capable of performing a motion to support an object while moving in a direction perpendicular to the gripping motion direction of the first finger while the first finger is performing a gripping motion.
• the second finger can be moved in a direction perpendicular to the direction of the gripping motion of the first finger to support an object.
• FIG. 1 is an external view that generally illustrates an example configuration of a robot hand according to an embodiment of the present disclosure.
• FIG. 2 is an explanatory diagram showing, in a simplified form, a first example of a gripping motion and a supporting motion performed by a robot hand according to an embodiment.
• FIG. 3 is an explanatory diagram that illustrates a first example of a gripping motion and a supporting motion by a robot hand according to an embodiment.
• FIG. 4 is an explanatory diagram that illustrates a second example of the gripping and supporting motions performed by the robot hand according to one embodiment.
• FIG. 5 is an explanatory diagram that illustrates an example of the arrangement of supporting fingers when the direction of a gripping motion by a robot hand according to one embodiment coincides with the direction of gravity.
• FIG. 1 is an external view that generally illustrates an example configuration of a robot hand according to an embodiment of the present disclosure.
• FIG. 2 is an explanatory diagram showing, in a simplified form, a first example of a gripping
• FIG. 6 is an explanatory diagram that illustrates an example of the arrangement of supporting fingers when the direction of a gripping motion by a robot hand according to one embodiment is opposite to the direction of gravity.
• FIG. 7 is an explanatory diagram showing an overview of the force/moment balance control when grasping an object.
• FIG. 8 is an explanatory diagram showing an overview of an initial slippage that occurs between a finger and an object.
• FIG. 9 is an explanatory diagram showing an elastic contact model between a finger and an object when grasping the object.
• FIG. 10 is an explanatory diagram showing an overview of the amount of shear displacement of a finger when grasping an object.
• FIG. 11 is a block diagram showing an outline of a control block for realizing gripping force control.
• FIG. 12 is an explanatory diagram showing an overview of the position and orientation constraint of an object when grasping the object.
• FIG. 13 is a block diagram illustrating an example of the configuration of a control block of a robot system including a robot hand according to an embodiment.
• FIG. 14 is a block diagram illustrating a first configuration example of a control block of a robot hand according to one embodiment.
• FIG. 15 is a block diagram illustrating a second configuration example of a control block of a robot hand according to an embodiment.
• FIG. 16 is a block diagram illustrating a third example of the configuration of a control block of a robot hand according to an embodiment.
• FIG. 17 is a block diagram illustrating a fourth example of the configuration of the control block of a robot hand according to an embodiment.
• FIG. 13 is a block diagram illustrating an example of the configuration of a control block of a robot system including a robot hand according to an embodiment.
• FIG. 14 is a block diagram illustrating a first configuration example of a control
• FIG. 18 is a flowchart that illustrates a first example of a control operation of a robot hand according to one embodiment.
• FIG. 19 is a flowchart that illustrates a second example of the control operation of the robot hand according to one embodiment.
• FIG. 20 is a flowchart that illustrates a third example of the control operation of the robot hand according to one embodiment.
• FIG. 21 is an external view that shows a schematic view of a state in which the supporting fingers are rotated 180° in a robot hand according to one embodiment.
• FIG. 22 is an external view that shows a schematic view of a state in which the supporting fingers are rotated 180° in a robot hand according to one embodiment.
• FIG. 21 is an external view that shows a schematic view of a state in which the supporting fingers are rotated 180° in a robot hand according to one embodiment.
• FIG. 22 is an external view that shows a schematic view of a state in which the supporting fingers are rotated 180° in a robot hand according to one embodiment.
• FIG. 23 is an external view that illustrates a schematic example of a robot hand according to one embodiment in which an object is grasped by rotating the supporting fingers by 180 degrees.
• FIG. 24 is an external view that illustrates a schematic example of a robot hand according to one embodiment, in which an object is grasped by rotating the supporting fingers by 180 degrees.
• FIG. 25 is an external view that illustrates a schematic configuration example of a robot hand according to one embodiment that includes multiple supporting fingers.
• FIG. 26 is an external view that illustrates a schematic example of a robot hand according to one embodiment, in which an object is grasped by a plurality of supporting fingers.
• FIG. 27 is an external view that illustrates a schematic example of a robot hand according to one embodiment, in which an object is grasped by a plurality of supporting fingers.
• Fig. 1 is an external view that shows a schematic configuration example of a robot hand 10 according to an embodiment of the present disclosure.
• Fig. 2 is an explanatory diagram showing, in a simplified manner, a first example of a gripping motion and a supporting motion by the robot hand 10 according to an embodiment.
• Fig. 3 is an explanatory diagram that shows, in a simplified manner, a first example of a gripping motion and a supporting motion by the robot hand 10 according to an embodiment.
• Fig. 4 is an explanatory diagram that shows, in a simplified manner, a second example of a gripping motion and a supporting motion by the robot hand 10 according to an embodiment. Note that Figs. 3 and 4 show the robot hand 10 as viewed from, for example, the top.
• a robot hand 10 (hereinafter simply referred to as “hand 10") according to one embodiment has multiple fingers for grasping a grasped object 50 (hereinafter simply referred to as "object 50"), including a first grasping finger 11 and a second supporting finger 12.
• the hand 10 also has a circular palm 30 with multiple fingers connected around its periphery.
• the hand 10 can be connected to, for example, a robot arm via an arm connector 40.
• a flexible layer 21 may be provided as an elastic body on the surfaces (inner surfaces, surfaces that come into contact with the grasped object 50) of the grasping fingers 11 and the supporting fingers 12, and on the surface of the palm 30.
• the contact area between the inner surfaces of the supporting fingers 12 and the object 50 when supporting can be increased, allowing for a stable grip.
• At least one of various sensors such as a proximity sensor, a tactile sensor, and a torque sensor may be provided on the gripping fingers 11, the supporting fingers 12, and the palm 30.
• the grasping finger 11 has at least one joint 20 and is configured to be able to perform a grasping action on the object 50.
• the supporting fingers 12 are configured to be able to support the object 50 while moving in a direction perpendicular to the direction of the gripping motion of the gripping fingers 11 while the gripping motion is being performed by the gripping fingers 11.
• the supporting fingers 12 are also configured to be able to move independently of the palm 30.
• the supporting finger 12 may be capable of rotational movement around the yaw axis Ay at a position offset from the base of the supporting finger 12.
• the supporting finger 12 may be capable of rotating 360° around the yaw axis Ay so as not to interfere with the grasping finger 11.
• the supporting fingers 12 can rotate around the yaw axis Ay, which is offset from the base, to avoid interference between the gripping fingers 11 and the supporting fingers 12 when performing a gripping motion with the gripping fingers 11. Also, by rotating around the yaw axis Ay, which is offset, the distance from the fulcrum to the point of force can be made longer due to the principle of leverage when gripping the object 50, making it possible to grip an object with large inertia.
• the palm 30 is shaped like a circle, maximizing the size of the palm 30 while minimizing the distance between the fingers and the palm 30.
• the hand 10 is made compact while increasing the contact area with the object 50, realizing stable gripping, and the distance from the fulcrum to the point of force on the object 50 is long, making it possible to grip an object with large inertia.
• the yaw axis Ay which is the rotation axis, is separated from the palm 30, so that the positional relationship of the sensors provided on the palm 30 is fixed, improving controllability. Separating the rotation axis from the palm 30 makes it possible to rotate the supporting fingers 12 while maintaining contact between the object 50 and the palm 30, making it possible to safely grip and manipulate the object 50.
• the supporting fingers 12 may be capable of linear movement in a direction along a linear axis Al that is perpendicular to the direction of the gripping action by the gripping fingers 11.
• the supporting fingers 12 may further be capable of rotational action about a pitch axis Ap that is perpendicular to the direction of the gripping action by the gripping fingers 11. This may realize a supporting action by the supporting fingers 12 without interfering with the gripping fingers 11.
• a tactile sensor may be provided on the inner surface of the supporting finger 12 to detect contact with the object 50 on the inner surface of the supporting finger 12.
• a torque sensor may be provided at the base of the supporting finger 12.
• a contact detection unit 104 may be provided that detects contact between the supporting finger 12 and the object 50 based on the detection result of at least one of the tactile sensor and torque sensor provided on the supporting finger 12.
• a control unit 120 may also be provided that controls the operation of the supporting finger 12 based on the detection result by the contact detection unit 104.
• the hand 10 may be provided with at least one of a proximity sensor capable of detecting the positions of the supporting finger 12 and the object 50, and a tactile sensor provided on the inner surface of the supporting finger 12.
• a proximity sensor capable of detecting the positions of the supporting finger 12 and the object 50
• a tactile sensor provided on the inner surface of the supporting finger 12.
• an estimation unit contact position estimation unit 106, contact surface normal estimation unit 107
• a position and orientation calculation unit object position and orientation calculation unit 108 that calculates the position and orientation of the object 50 based on the estimation result by the estimation unit may be provided.
• the tactile sensor may be at least one of a pressure distribution sensor, a force sensor, a vision type sensor, a magnetic type sensor, etc.
• the proximity sensor may also include at least one of a Time of Flight sensor, a millimeter wave sensor, an ultrasonic sensor, a laser sensor, LiDAR (Light Detection and Ranging), a stereo camera, a pattern projection sensor, an event camera, etc.
• the hand 10 may be provided with an estimation unit (contact position estimation unit 106, contact surface normal estimation unit 107) that estimates the object gripping width of the gripping finger 11 and the supporting finger 12 based on the joint angle (e.g., yaw axis rotation angle) of the supporting finger 12 and contact information between the supporting finger 12 and the object 50, and estimates the contact position and contact surface normal of the inner surface of the supporting finger 12 with respect to the object 50 based on the estimated object gripping width.
• the joint angle e.g., yaw axis rotation angle
• the hand 10 may further include a position and orientation calculation unit (object position and orientation calculation unit 108) that calculates the position and orientation of the object 50 based on the estimation result by the estimation unit, and a control unit 120 that controls the operation of the gripping finger 11 and the supporting finger 12 based on the calculation result by the position and orientation calculation unit.
• a position and orientation calculation unit object position and orientation calculation unit 108 that calculates the position and orientation of the object 50 based on the estimation result by the estimation unit
• control unit 120 that controls the operation of the gripping finger 11 and the supporting finger 12 based on the calculation result by the position and orientation calculation unit.
• the object gripping width is estimated from the joint angles and contact information, and the contact position of the inner surface of the supporting finger 12 with respect to the object 50 is estimated, thereby enabling balance control of forces and moments to be achieved, and stable gripping can be achieved.
• the object gripping width is estimated from the joint angles and contact information, and the contact position of the supporting finger 12 with respect to the object 50 and the contact surface normal are estimated, thereby enabling position and orientation control of the object 50 to be achieved, and stable gripping can be achieved.
• At least one of the grasping fingers 11 and the supporting fingers 12 may be provided with a tactile sensor and a flexible layer 21.
• a slippage detection unit 101 may be provided that detects initial slippage between the grasping fingers 11 or the supporting fingers 12 and the object 50 based on the detection result of the tactile sensor
• a gripping force calculation unit 102 may be provided that calculates a gripping force for gripping the object 50 based on the detection result of the initial slippage by the slippage detection unit 101.
• a control unit 120 may also be provided that controls the operation of the grasping fingers 11 and the supporting fingers 12 based on the calculation result by the gripping force calculation unit 102. This makes it possible to determine an appropriate gripping force even if the object 50 is an unknown object.
• the hand 10 may be provided with a center of gravity estimation unit (object position/orientation calculation unit 108) that estimates the center of gravity of the object 50, as shown in Figs. 14 to 17 described later.
• a control unit 120 may be provided that determines the position at which the supporting finger 12 supports the object 50 based on the relationship between the center of gravity of the object 50, the direction of gravity acting on the object 50, and the direction of the gripping motion by the gripping finger 11.
• the center of gravity estimation unit may estimate the center of gravity of the object 50 based on the detection result of at least one sensor among a proximity sensor, a torque sensor provided at the base of the supporting finger 12, and a tactile sensor provided on the inner surface of the supporting finger 12.
• the proximity sensor may be provided on the inner surface of the supporting finger 12, or may be a proximity sensor such as a vision sensor provided at a position different from the supporting finger 12.
• FIG. 5 is an explanatory diagram that shows a schematic example of the arrangement of the supporting fingers 12 when the direction of the gripping motion of the robot hand 10 according to one embodiment is the same as the direction of gravity.
• FIG. 6 is an explanatory diagram that shows a schematic example of the arrangement of the supporting fingers 12 when the direction of the gripping motion of the robot hand 10 according to one embodiment is opposite to the direction of gravity.
• the posture of the hand 10 and the finger arrangement it is possible to determine the posture of the hand 10 and the finger arrangement according to the object 50. For example, as shown in FIG. 5, in the case of a posture of the hand 10 in which the direction of gravity coincides with the direction from the grasping fingers 11 to the supporting fingers 12, it is advisable to arrange the supporting fingers 12 so as to approach the position of the center of gravity of the object 50. On the other hand, in the case of a posture of the hand 10 in which the direction of gravity coincides with the direction from the grasping fingers 11 to the supporting fingers 12, it is advisable to arrange the supporting fingers 12 so as to move away from the position of the center of gravity of the object 50, as shown in FIG. 6, for example.
• the center of gravity position of the object 50 may be estimated from an image acquired by a vision sensor.
• machine learning may be used for the estimation.
• a torque sensor provided at the base of the supporting finger 12 may be used to estimate the center of gravity position of the object 50.
• the joint angle of the supporting finger 12 is further rotated slightly, and the torque sensor value at that time is obtained.
• the center of gravity position estimation unit can estimate the direction in which the center of gravity is located by obtaining and comparing the values in both directions.
• a tactile sensor provided on the inner surface of the supporting finger 12 may be used to estimate the center of gravity position of the object 50.
• the joint angle of the supporting finger 12 is further rotated slightly, and pressure distribution information at that time is obtained.
• the center of gravity position estimation unit can estimate the direction in which the center of gravity is located by obtaining and comparing values in both directions.
• a proximity sensor provided on the inner surface of the supporting finger 12 may be used to estimate the center of gravity position of the object 50.
• the joint angle is further rotated slightly and distance measurement information at that time is obtained.
• the center of gravity position estimation unit can estimate the direction in which the center of gravity is located by obtaining and comparing values in both directions.
• the following three controls may be executed for each finger. This allows various gripping forms to be realized by the same control method.
• the gripping force control using initial slippage may be executed for at least one finger. 2.3. may be executed for each finger. 1. Grip force control using initial slippage 2. Force/moment balance control using the contact position on the object 50 3. 3D position and orientation control of the object 50 using the contact position on the object 50 and the contact surface normal
• the hand 10 is capable of grasping and supporting an object while gripping it. By being able to handle a variety of gripping forms in a unified manner, it is not necessary to determine whether to switch between multiple gripping forms, making control easier. With grip force control using initial slippage, it is possible to determine an appropriate grip force for an unknown object. Furthermore, with force/moment balance control using the contact position with respect to the object 50, it is possible to determine the magnitude and direction of the grip force, making it possible to achieve a stable grip.
• FIG. 7 is an explanatory diagram showing an overview of force-moment balance control when grasping an object.
• Fig. 7 shows a case where an object 50 is grasped by any two fingers 1 and 2 of a hand 10.
• Equation (1) The control input that satisfies the balance of the force and moment is shown in formula (1).
• Jq i is the Jacobian matrix related to the finger joint angle and the fingertip hemisphere center position
• a i is the fingertip center
• O is the geometric center of each contact point
• C i is each contact point
• f d is the target grip force
• K f is the force control gain.
• Formula (1) determines the fingertip force vector from each fingertip A i to the geometric center O of each contact point C i , and converts it into each joint torque using the transpose of the Jacobian matrix.
• the relative stiffness of each finger and the geometric center (between fingers in the case of two fingers) is controlled. It is necessary to set an appropriate grip force f d , but in the hand 10 according to one embodiment, the grip force f d is determined by utilizing initial slippage.
• FIG. 8 is an explanatory diagram showing an overview of an initial slippage that occurs between a finger and an object 50.
• Initial slippage is a precursor to slippage, in which only a portion of the contact surface begins to slip.
• slippage also called total slippage
• relative movement occurs between the finger and the object 50 that was in contact.
• blunting refers to a state in which static friction occurs over the entire contact surface between the finger and the object 50 being held, for example, and there is no relative movement between the two.
• slippage (total slippage) refers to a state in which kinetic friction occurs and there is relative movement between the two objects in contact. Here, it refers to slippage in which kinetic friction occurs over the entire contact surface between the finger and the object 50 being held, and there is relative movement between the two.
• Initial slippage is also known as a precursor phenomenon to the above-mentioned slippage (total slippage), and is a phenomenon in which dynamic friction occurs on a part of the contact surface between the finger and the grasped object 50.
• This initial slippage state is said to exist during the transition from the "sticky” state to the "slippage” state. In the initial slippage state, no relative movement occurs between the finger and the grasped object 50.
• the contact area is divided into a "sticky area” where no initial slippage occurs (i.e., a partial area of the contact surface between the finger and the grasped object 50 where static friction occurs) and a “slippery area” where initial slippage occurs (i.e., a partial area of the contact surface between the finger and the grasped object 50 where kinetic friction occurs).
• the degree of slippage can be expressed as the ratio of these two areas.
• the ratio of the sticking area to the contact area is defined as the "sticking rate.”
• Fig. 9 is an explanatory diagram showing an elastic contact model between a finger and an object 50 when gripping an object.
• Fig. 10 is an explanatory diagram showing an overview of a shear displacement amount ux of a finger when gripping an object. Equation (2) can be derived from Hertz's contact theorem.
• the left side of equation (2) indicates the ratio of the area of the contact surface where slippage does not occur, and is called the sticking rate.
• the initial slippage can be quantified by a physical quantity called the sticking rate.
• the grip force is calculated by applying the sum of the deformation amount vectors in the shear direction detected by each finger as an input to PD (Proportional Differential) control (Equation (3)).
• the sum of the deformation vectors in the shear direction of each elastic body is taken to take into account not only slip in any translational direction and rotational direction relative to the contact surface, but also slip in the rotational direction relative to an axis perpendicular to the contact surface.
• FIG 11 shows an overview of the control block that realizes the above gripping force control.
• the control block that realizes grip force control includes a reference value generation unit 61, a slip prevention control unit (PD control unit) 62, a force/moment balance control unit 63, an actuator control unit 64, an LPF (low pass filter) 65, and a shear displacement amount integration unit 66.
• (3D position and attitude control) 12 is an explanatory diagram showing an overview of the position and orientation constraint of an object 50 when grasping the object.
• FIG. 12 a case where an object 50 is grasped by any two fingers 1 and 2 of a hand 10 is shown.
• the control input for the three-dimensional position constraint is shown in formula (4).
• O is the object position (geometric center of each contact point)
• Od is the target object position
• Kp is the position control gain
• J( qi ) is the Jacobian matrix for each joint angle of the attitude angular velocity vector at the center position of the fingertip hemisphere.
• Formula (4) performs control to the target position Od , with the geometric center O of the contact points of each finger being the position of the object 50.
• the control input for the posture constraint is shown in formula (5).
• rx , ry , and rz are the object posture (contact surface normal unit vector, contact tangent line unit vector)
• rxd , ryd , and rzd are the object target posture
• K0 is the posture control gain
• J( ⁇ i ) is the Jacobian matrix for each joint angle of the posture angular velocity vector at the center position of the fingertip hemisphere.
• Formula (5) estimates the posture of the object 50 using the contact surface normal unit vector and the contact tangent line unit vector, and controls it to the target posture.
• the cross product When the cross product is taken as rx ⁇ rxd , it becomes a vector representing the error between the X-axis vector rx of the current posture and the X-axis vector rxd of the target posture, and by applying a rotational moment to the object 50 according to this vector, it becomes a control input that reduces the posture error.
• the Y component and the Z component The same applies to the Y component and the Z component.
• DFT The definition of DFT is shown in formula (6).
• the real scalar values G, g, and the complex scalar value W are the converted value, the converted value, and the rotator, respectively, and the scalar value N is an arbitrary integer.
• the DFT matrix can be expressed using the matrix FN shown in formula (7).
• g indicates the external force f1 ... fnT applied to the n-finger robot finger or the position x1 ... xnT of the n-finger robot finger.
• G is the extraction mode of the "force and moment balance control mode" and the "position and orientation control mode” (formula (8)).
• fg indicates the internal force acting on the hand 10 and the object 50
• xg indicates the size and deformation amount of the grasped object 50
• fm indicates the force contributing to the movement of the object 50
• xm indicates the center of gravity position and orientation of the object 50 (formula (9)). Therefore, in the force and moment balance control mode, fg is calculated and controlled so that the object 50 can be grasped without slipping. In the position and orientation control mode, fm is controlled so that xm converges to a target value.
• FIG. 13 is a block diagram showing an example of the configuration of a control block of a robot system including a robot hand 10 according to an embodiment.
• control blocks of the robot system may be configured by a computer having, for example, one or more Central Processing Units (CPUs), one or more Read Only Memories (ROMs), and one or more Random Access Memories (RAMs).
• CPUs Central Processing Units
• ROMs Read Only Memories
• RAMs Random Access Memories
• processing of each control block may be realized by one or more CPUs executing processing based on programs stored in one or more ROMs or RAMs.
• processing of each control block may also be realized by one or more CPUs executing processing based on programs supplied from outside, for example, via a wired or wireless network.
• the robot system includes a task command unit 300, a recognition sensor processing unit 310, a motion planning unit 320, a grip control unit 330, a control calculation unit 340, and an actuator unit 350 as control blocks for the robot 360.
• the task command unit 300 outputs task information, task start triggers, etc.
• the recognition sensor processing unit 310 has a surrounding environment recognition processing unit 311 and a hand sensor processing unit 312.
• the surrounding environment recognition processing unit 311 has various sensors for recognizing the surrounding environment.
• the surrounding environment recognition processing unit 311 processes various sensor data based on task information from the task command unit 300 and task start triggers, and outputs data such as RGB images, depth images, distance, point cloud, and event data.
• the hand sensor processing unit 312 has various sensors.
• the hand sensor processing unit 312 processes various sensor data based on the task information from the task command unit 300 and the task start trigger, and outputs data such as an RGB image, a depth image, distance, Point Cloud, event data, force/pressure, vibration, acceleration, amount of slippage, contact position, and contact area.
• the motion planning unit 320 has a carriage trajectory planning unit 321, an arm trajectory planning unit 322, and a grip planning unit 323.
• the cart trajectory planning unit 321 outputs data such as the cart trajectory, the target point of the cart 361, the wheel acceleration of the cart 361, the speed of the cart 361, and the position of the cart 361 based on the output data from the surrounding environment recognition processing unit 311.
• the arm trajectory planning unit 322 outputs data such as the arm trajectory, the target point of the arm 362, the joint acceleration of the arm 362, the speed of the arm 362, and the position of the arm 362 based on the output data from the surrounding environment recognition processing unit 311.
• the grip planning unit 323 outputs data such as the grip position by the hand 10 and the grip posture by the hand 10 based on the output data from the surrounding environment recognition processing unit 311 and the hand sensor processing unit 312.
• the grip control unit 330 has a proximity detection unit 331, an initial slippage detection unit 332, an object position/posture/grip form/finger trajectory calculation unit 333, and a grip force calculation unit 334.
• the grip control unit 330 may further have a sensor processing block (contact position detection unit, contact force detection unit, etc.) that is added as necessary.
• the proximity detection unit 331 outputs data such as the distance to the object 50 in the hand 10, the object surface angle, and object position and orientation information based on the output data from the hand sensor processing unit 312.
• the initial slippage detection unit 332 outputs data such as the amount of slippage of the hand 10 relative to the object 50 and a contact flag for the object 50 in the hand 10 based on the output data from the hand sensor processing unit 312.
• the object position and orientation, gripping form, and finger trajectory calculation unit 333 outputs data such as the gripping form of the hand 10 and the finger trajectory of the hand 10 based on the output data from the proximity detection unit 331 and the initial slippage detection unit 332.
• the gripping force calculation unit 334 outputs data on the gripping force of the hand 10 based on the output data from the initial slippage detection unit 332.
• the control calculation unit 340 has a cart control calculation unit 341, an arm control calculation unit 342, a hand finger control calculation unit 343, and a robot control calculation unit 344.
• the cart control calculation unit 341 outputs joint command (position, speed, acceleration, and force) data for the cart 361 based on output data from the cart trajectory planning unit 321.
• the arm control calculation unit 342 outputs joint command (position, speed, acceleration, and force) data for the arm 362 based on output data from the arm trajectory planning unit 322 and the proximity detection unit 331.
• the hand finger control calculation unit 343 outputs joint command (position, speed, acceleration, and force) data for the hand 10 based on output data from the object position/posture/grasping form/finger trajectory calculation unit 333 and the grip force calculation unit 334.
• the robot control calculation unit 344 outputs actuator command (position, speed, acceleration, and force) data to the actuator unit 350 of each part of the robot 360 based on the output data from the cart control calculation unit 341, the arm control calculation unit 342, and the hand finger control calculation unit 343.
• FIG. 14 is a block diagram showing a first example of the configuration of the control block of the robot hand 10 according to one embodiment.
• Fig. 14 shows a configuration example in which a tactile sensor is provided on the gripping finger 11 and a torque sensor is provided on the supporting finger 12, as the first example of the control block.
• a simple sensor configuration is expected to reduce the size and cost of the hand 10.
• the robot hand 10 has a sensing unit 110 and a control unit 120 as control blocks.
• control blocks of the robot hand 10 may be configured by a computer having, for example, one or more CPUs, one or more ROMs, and one or more RAMs.
• the processing of each control block may be realized by one or more CPUs executing processing based on a program stored in one or more ROMs or RAMs.
• the processing of each control block may be realized by one or more CPUs executing processing based on a program supplied from the outside, for example, via a wired or wireless network.
• the sensing unit 110 has a torque detection unit 103, a contact detection unit 104, an object gripping width estimation unit 105, a contact position estimation unit 106, and a contact surface normal estimation unit 107 as control blocks for the supporting finger 12.
• the sensing unit 110 has a tactile information detection unit 100, a slippage detection unit 101, a contact detection unit 104, a contact position estimation unit 106, and a contact surface normal estimation unit 107 as a control block for the gripping finger 11.
• the sensing unit 110 also includes a gripping force calculation unit 102 and an object position and orientation calculation unit 108.
• the control unit 120 has a joint torque calculation unit 200, a motion control unit 201, and an actuator unit 202.
• the tactile information detection unit 100 in the control block of the gripping fingers 11 includes a tactile sensor provided on the gripping fingers 11, and a sensor signal acquisition processing unit that processes a sensor signal from the tactile sensor provided on the gripping fingers 11.
• the slippage detection unit 101 in the control block of the gripping fingers 11 calculates the amount of slippage using information from the tactile information detection unit 100 in the control block of the gripping fingers 11.
• the torque detection unit 103 includes a torque sensor and a sensor signal acquisition processing unit that processes the sensor signal from the torque sensor.
• the contact detection unit 104 in the control block of the supporting finger 12 detects the presence or absence of contact between the supporting finger 12 and the object 50 using the torque value detected by the torque detection unit 103.
• the object gripping width estimation unit 105 calculates the object gripping width from the joint angle of the supporting finger 12 and the contact information.
• the contact detection unit 104 in the control block of the gripping fingers 11 detects whether or not there is contact between the gripping fingers 11 and the object 50 based on the detection results of a tactile sensor provided on the gripping fingers 11.
• the contact position estimation unit 106 in the control block of the supporting finger 12 estimates the contact position with respect to the object 50 using the object gripping width calculated by the object gripping width estimation unit 105 and the model information of the hand 10.
• the contact position estimation unit 106 in the control block of the gripping fingers 11 estimates the contact position with respect to the object 50 based on the detection results of the tactile sensor provided on the gripping fingers 11.
• the contact surface normal estimation unit 107 in the control block of the supporting finger 12 estimates the contact surface normal using the grip width calculated by the object grip width estimation unit 105 and the model information of the hand 10.
• the contact surface normal estimation unit 107 in the control block of the gripping fingers 11 estimates the contact surface normal based on the detection results of the tactile sensor provided on the gripping fingers 11.
• the object position/orientation calculation unit 108 calculates the object position/orientation using the contact position, contact surface normal, and position/orientation information of the hand 10 with respect to the object 50 calculated by the contact position estimation unit 106 and the contact surface normal estimation unit 107 in the control blocks of the gripping fingers 11 and the supporting fingers 12.
• the gripping force calculation unit 102 calculates the gripping force using the amount of slippage calculated by the slippage detection unit 101 in the control block of the gripping fingers 11.
• the joint torque calculation unit 200 calculates each joint torque by force/moment balance control based on the grip force calculated by the grip force calculation unit 102 and the contact position with respect to the object 50 estimated by the contact position estimation unit 106.
• the joint torque calculation unit 200 calculates each joint torque due to object position and orientation control from the contact position of the contact position estimation unit 106 and the contact surface normal estimation unit 107 relative to the object 50 and the contact surface normal.
• the joint torque calculation unit 200 calculates each joint torque that achieves both of these by utilizing mode conversion using a DFT matrix.
• the motion control unit 201 performs a certain position control or impedance control until contact is detected based on the contact information detected by the contact detection unit 104. After contact is detected, the motion control unit 201 performs torque control based on the torque command value calculated by each joint torque calculation unit 200.
• the actuator unit 202 includes a movable part that operates the robot having the hand 10 and a control processing block for the movable part.
• FIG. 15 is a block diagram showing a second example of the configuration of the control block of the robot hand 10 according to an embodiment.
• Fig. 15 shows a configuration example in which a tactile sensor is provided on the gripping finger 11 and a tactile sensor is provided on the supporting finger 12, as the second example of the control block. Note that a description of the control block that performs the same processing as in the first example of the configuration of Fig. 14 will be omitted.
• the robot hand 10 has a sensing unit 110 and a control unit 120 as control blocks.
• the sensing unit 110 has a tactile information detection unit 100, a slippage detection unit 101, a contact detection unit 104, a contact position estimation unit 106, and a contact surface normal estimation unit 107 as a control block for the supporting finger 12.
• the sensing unit 110 has a tactile information detection unit 100, a slippage detection unit 101, a contact detection unit 104, a contact position estimation unit 106, and a contact surface normal estimation unit 107 as a control block for the gripping finger 11.
• the sensing unit 110 also includes a gripping force calculation unit 102 and an object position and orientation calculation unit 108.
• the control unit 120 has a joint torque calculation unit 200, a motion control unit 201, and an actuator unit 202.
• the tactile information detection unit 100 in the control block of the supporting finger 12 includes a tactile sensor provided on the supporting finger 12, and a sensor signal acquisition processing unit that processes a sensor signal from the tactile sensor provided on the supporting finger 12.
• the slippage detection unit 101 in the control block of the supporting finger 12 calculates the amount of slippage using information from the tactile information detection unit 100 in the control block of the supporting finger 12.
• the contact detection unit 104 in the control block of the supporting finger 12 detects whether or not the supporting finger 12 is in contact with the object 50 based on the detection results of the tactile sensor provided on the supporting finger 12.
• the contact position estimation unit 106 in the control block of the supporting finger 12 estimates the contact position with respect to the object 50 based on the detection results of the tactile sensor provided on the supporting finger 12.
• the contact surface normal estimation unit 107 in the control block of the supporting finger 12 estimates the contact surface normal based on the detection results of the tactile sensor provided on the supporting finger 12.
• the gripping force calculation unit 102 calculates the gripping force using the amount of slippage calculated by the slippage detection unit 101 in the control blocks of the gripping fingers 11 and the supporting fingers 12.
• FIG. 16 is a block diagram showing a third example of the configuration of the control block of the robot hand 10 according to an embodiment.
• Fig. 16 shows a configuration example in which a tactile sensor is provided on the gripping finger 11 and a proximity sensor is provided on the supporting finger 12, as the third example of the control block. Note that a description of the control block that performs the same processing as in the first example of the configuration of Fig. 14 will be omitted.
• the robot hand 10 has a sensing unit 110 and a control unit 120 as control blocks.
• the sensing unit 110 has a contact detection unit 104, a contact position estimation unit 106, a contact surface normal estimation unit 107, and a distance information detection unit 109 as a control block for the supporting finger 12.
• the sensing unit 110 has a tactile information detection unit 100, a slippage detection unit 101, a contact detection unit 104, a contact position estimation unit 106, and a contact surface normal estimation unit 107 as a control block for the gripping finger 11.
• the sensing unit 110 also includes a gripping force calculation unit 102 and an object position and orientation calculation unit 108.
• the control unit 120 has a joint torque calculation unit 200, a motion control unit 201, and an actuator unit 202.
• the distance information detection unit 109 in the control block of the supporting finger 12 includes a distance measurement sensor as a proximity sensor provided on the supporting finger 12, and a sensor signal acquisition processing unit that processes a sensor signal from the distance measurement sensor.
• the contact detection unit 104 in the control block of the supporting finger 12 detects whether or not the supporting finger 12 is in contact with the object 50 based on the detection results of the distance measurement sensor provided on the supporting finger 12.
• the contact position estimation unit 106 in the control block of the supporting finger 12 estimates the contact position with respect to the object 50 based on the detection results of the distance measurement sensor provided on the supporting finger 12.
• the contact surface normal estimation unit 107 in the control block of the supporting finger 12 estimates the contact surface normal based on the detection results of the distance measurement sensor provided on the supporting finger 12.
• the gripping force calculation unit 102 calculates the gripping force using the amount of slippage calculated by the slippage detection unit 101 in the control block of the gripping fingers 11.
• FIG. 17 is a block diagram showing a fourth example of the configuration of the control block of the robot hand 10 according to an embodiment.
• Fig. 17 shows a fourth example of the configuration of the control block in which a tactile sensor is provided on the gripping finger 11 and a tactile sensor and a proximity sensor are provided on the supporting finger 12. Note that a description of the control block that performs the same processing as in the first example of the configuration of Fig. 14 will be omitted.
• the supporting finger 12 uses a combination of proximity information and tactile information to obtain an accurate contact position with respect to the object 50 and the position and orientation of the object 50, enabling flexible and stable gripping according to the situation.
• the robot hand 10 has a sensing unit 110 and a control unit 120 as control blocks.
• the sensing unit 110 has a tactile information detection unit 100, a slippage detection unit 101, a contact detection unit 104, a contact position estimation unit 106, and a contact surface normal estimation unit 107 as a control block for the supporting finger 12.
• the sensing unit 110 has a tactile information detection unit 100, a slippage detection unit 101, a contact detection unit 104, a contact position estimation unit 106, a contact surface normal estimation unit 107, and a distance information detection unit 109 as a control block for the gripping finger 11.
• the sensing unit 110 also includes a gripping force calculation unit 102 and an object position and orientation calculation unit 108.
• the control unit 120 has a joint torque calculation unit 200, a motion control unit 201, and an actuator unit 202.
• the tactile information detection unit 100 in the control block of the supporting finger 12 includes a tactile sensor provided on the supporting finger 12, and a sensor signal acquisition processing unit that processes a sensor signal from the tactile sensor provided on the supporting finger 12.
• the distance information detection unit 109 in the control block of the supporting finger 12 includes a distance measurement sensor as a proximity sensor provided on the supporting finger 12, and a sensor signal acquisition processing unit that processes a sensor signal from the distance measurement sensor.
• the slippage detection unit 101 in the control block of the supporting finger 12 calculates the amount of slippage using information from the tactile information detection unit 100 in the control block of the supporting finger 12.
• the contact detection unit 104 in the control block of the supporting finger 12 detects whether or not the supporting finger 12 is in contact with the object 50 based on the detection results of the tactile sensor provided on the supporting finger 12.
• the contact position estimation unit 106 in the control block of the supporting finger 12 estimates the contact position with respect to the object 50 based on the detection results of the tactile sensor and distance measurement sensor provided on the supporting finger 12.
• the contact surface normal estimation unit 107 in the control block of the supporting finger 12 estimates the contact surface normal based on the detection results of the tactile sensor and distance measurement sensor provided on the supporting finger 12.
• the gripping force calculation unit 102 calculates the gripping force using the amount of slippage calculated by the slippage detection unit 101 in the control blocks of the gripping fingers 11 and the supporting fingers 12.
• Fig. 18 is a flowchart that outlines a first example of the control operation of the robot hand 10 according to an embodiment.
• Fig. 18 shows an example of the control operation in the case where the gripping fingers 11 are provided with a tactile sensor and the supporting fingers 12 are provided with a torque sensor as the configuration of the hand 10, similar to the first configuration example shown in Fig. 14.
• Fig. 18 also shows an example of the control operation in the case where the gripping fingers 11 have a pitch axis Ap with two degrees of freedom, and the supporting fingers 12 have a yaw axis Ay with one degree of freedom at a position offset from the base.
• Fig. 18 also shows an example of the control operation in the case where the center of gravity position of the object 50 is known.
• a grasping action is performed as a control action for the grasping fingers 11 (step S111).
• contact between the grasping fingers 11 and the object 50 is detected based on the detection results of the tactile sensors (step S112).
• a control action for the grasping fingers 11 initial slippage is detected based on the detection results of the tactile sensors, and the gripping force is determined (step S113).
• a contact position and a contact surface normal are detected based on the detection results of the tactile sensors (step S114).
• the supporting fingers 12 are opened by rotating about the yaw axis Ay (step S211).
• contact between the supporting fingers 12 and the object 50 is detected based on the detection result of the torque sensor (step S212).
• the object gripping width is calculated and estimated from the joint angle of the supporting fingers 12 and the contact information (step S213).
• the contact position and the contact surface normal are detected based on the object gripping width (step S214).
• the hand 10 calculates the object position and orientation based on the contact positions of the grasping fingers 11 and the supporting fingers 12 with respect to the object 50 and the contact surface normal (step S311).
• the hand 10 calculates command torques for the actuators of the grasping fingers 11 and the supporting fingers 12 by force/moment balance control and position/orientation control of the object 50 (step S312).
• Fig. 19 is a flowchart that outlines a second example of the control operation of the robot hand 10 according to an embodiment.
• Fig. 19 shows an example of the control operation in the case where the gripping fingers 11 are provided with a tactile sensor and the supporting fingers 12 are provided with a torque sensor as the configuration of the hand 10, similar to the first configuration example shown in Fig. 14.
• Fig. 19 also shows an example of the control operation in the case where the gripping fingers 11 have a pitch axis Ap with two degrees of freedom, and the supporting fingers 12 have a yaw axis Ay with one degree of freedom at a position offset from the base.
• Fig. 19 also shows an example of the control operation in the case where the center of gravity position of the object 50 is unknown.
• step S201 the relationship between the direction of gravity acting on the object 50 and the hand posture (see FIG. 5 and FIG. 6) is acquired (step S201).
• step S202 the position (direction) of the center of gravity of the object 50 is estimated (step S202).
• step S203 the direction (yaw axis rotation direction) for opening the supporting finger 12 is determined (step S203).
• step S211 the subsequent operations are the same as the first example of the control operation shown in FIG. 18.
• Fig. 20 is a flowchart that outlines a third example of the control operation of the robot hand 10 according to an embodiment.
• Fig. 20 shows an example of the control operation in the case where the gripping fingers 11 are provided with a tactile sensor and the supporting fingers 12 are provided with a torque sensor as the configuration of the hand 10, similar to the first configuration example shown in Fig. 14.
• Fig. 20 also shows an example of the control operation in the case where the gripping fingers 11 have a pitch axis Ap with two degrees of freedom, and the supporting fingers 12 have a linear axis A1 and a pitch axis Ap in a direction perpendicular to the movement direction of the gripping fingers 11.
• Fig. 20 also shows an example of the control operation in the case where the center of gravity position of the object 50 is unknown.
• step S201 the relationship between the direction of gravity acting on the object 50 and the hand posture is acquired (step S201).
• step S202 the position (direction) of the center of gravity of the object 50 is estimated (step S202).
• step S204 a movement amount (linear control amount) in a direction along the linear axis Al is determined (step S204).
• step S205 a linear movement in a direction along the linear axis Al and a rotation operation around the pitch axis Ap are controlled based on the determined linear control amount
• step S212 the subsequent operations are the same as the first example of the control operation shown in FIG. 18.
• At least one joint 20 capable of pitch axis rotation may be provided at a position other than the base of the finger, similar to the grasping finger 11, so that the angle of the supporting finger 12 can be freely changed.
• a task other than the grasping action e.g., opening a lid, exposing a lip, etc.
• the degree of freedom of operation is further improved.
• FIGS. 21 and 22 are external views that show a schematic representation of a state in which the supporting fingers of a robot hand 10 according to one embodiment have been rotated 180°.
• FIGS. 23 and 24 are external views that show a schematic representation of an example in which an object 50 has been grasped by rotating the supporting fingers 180° in a robot hand 10 according to one embodiment.
• the gripping fingers 11 and the supporting fingers 12 When the gripping fingers 11 and the supporting fingers 12 are rotated 180° from the state in which the gripping fingers 11 and the supporting fingers 12 face each other across the palm 30 as shown in FIG. 1 to the state in which the gripping fingers 11 and the supporting fingers 12 are rotated 180° as shown in FIG. 21 and FIG. 22, the gripping fingers 11 and the supporting fingers 12 can be arranged in a position where they overlap in the same radial direction on the palm 30. In this case, the distance between the gripping fingers 11 and the supporting fingers 12 can be reduced. This allows the contact area with the object 50 to be increased when gripping a thin object 50, and stable gripping can be achieved. Also, as shown in FIG. 23 and FIG.
• the fingers when gripping a cylindrical object 50, the fingers can be inserted from the inside of the cylindrical object 50, and the cylindrical object 50 can be gripped from the inside by the gripping fingers 11 and the supporting fingers 12. It becomes possible to grip the cylindrical object 50 in a mixed or narrow environment.
• FIG. 25 is an external view that shows a schematic configuration example of a robot hand 10 according to one embodiment, which has multiple supporting fingers 12.
• FIG. 26 and FIG. 27 are external views that show a schematic configuration example of a robot hand 10 according to one embodiment, which grasps an object 50 with multiple supporting fingers 12.
• the hand 10 may be configured with multiple supporting fingers 12.
• the multiple supporting fingers 12 may be movable in the same direction (for example, a rotational direction around the same yaw axis Ay).
• the finger width can be adjusted by adjusting the position of each of the multiple supporting fingers 12. As a result, as shown in Figures 26 and 27, the finger width can be widened to distribute the force, allowing for stable grip of the object 50. Furthermore, when performing an action such as pressing the surface of a large object with the fingertips, a stable action can be achieved by widening the fingertip surface to distribute the force.
• the thickness of the supporting fingers 12 can be adjusted.
• the robot hand 10 while the gripping fingers 11 are performing a gripping motion, the robot hand 10 can support the object 50 by moving the supporting fingers 12 in a direction perpendicular to the gripping motion direction of the gripping fingers 11. This makes it possible to stably grip the object 50.
• the robot hand 10 enables power grip regardless of the object width.
• the hand's functional configuration is divided into two parts, “grasping" and “supporting”, with the "grasping" function performing part of the power grip operation, and the "supporting" function allowing adjustment of the grip according to the object width.
• the fulcrum position by adjusting the fulcrum position, an object 50 with a large moment can be stably gripped, improving gripping stability.
• the robot hand 10 allows stable gripping even for an object 50 with a small gripping width, weight, and inertia.
• the present technology can be configured as follows. According to the present technology having the following configuration, while a first finger is gripping an object, the second finger can be moved in a direction perpendicular to the gripping direction of the first finger to support the object, thereby providing a robot hand capable of stably gripping an object.
• a first finger configured to be able to perform a gripping motion on an object; and a second finger configured to be able to move in a direction perpendicular to a direction of the gripping motion of the first finger while the first finger is performing a gripping motion and support the object.
• the second finger is capable of rotational movement around a yaw axis that is offset from a base of the second finger.
• the second finger is capable of rotating 360° around the yaw axis so as not to interfere with the first finger.
• a control unit that controls the movement of the second finger based on a detection result by the contact detection unit;
• the robot hand further comprising: (9) At least one of a proximity sensor capable of detecting the positions of the second finger and the object and a tactile sensor provided on an inner surface of the second finger; and an estimation unit that estimates a contact position and a contact surface normal of the inner surface of the second finger with respect to the object based on detection results of at least one of the proximity sensor and the tactile sensor.
• a position and orientation calculation unit that calculates a position and orientation of the object based on an estimation result by the estimation unit;
• a position and orientation calculation unit that calculates a position and orientation of the object based on an estimation result by the estimation unit;
• a control unit that controls the movement of the first finger and the second finger based on a calculation result by the gripping force calculation unit.
• a center of gravity position estimating unit that estimates a center of gravity position of the object; and a control unit that determines a position at which the second finger supports the object based on a relationship between a center of gravity of the object, a direction of gravity acting on the object, and a direction of a gripping motion by the first finger.
• the center of gravity position estimation unit estimates a center of gravity position of the object based on a detection result of at least one of the proximity sensor, the tactile sensor, and the torque sensor.
• a plurality of the second fingers are provided, The robot hand described in any one of (1) to (16) above, wherein the multiple second fingers are movable in the same direction.

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• Robotics (AREA)
• Mechanical Engineering (AREA)
• Human Computer Interaction (AREA)
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• 2024
  • 2024-01-17 JP JP2025505098A patent/JPWO2024185301A1/ja active Pending
  • 2024-01-17 WO PCT/JP2024/001091 patent/WO2024185301A1/ja not_active Ceased

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