Movable body control method, movable body control device, and time-varying output circuit

Abstract

This movable body control method is a method for controlling, by means of at least one movable portion and a contacting object that comes into contact with the movable portion, the contacting object or the movable portion itself, wherein: the control device controls the movable portion or the contacting object by applying a force to a surface of contact by means of a plurality of movable portions; when calculating a contact force generated at the surface of contact on the basis of energy, the total energy of the entire movable portion or the contacting object is considered not to increase, and to be the sum of stored energy and attenuating energy; and an external force term in the stored energy term includes information relating to slipping between the movable portion and the surface of contact of the contacting object, and is calculated in such a way that the external force term can be integrated.

Description

Movable body control method, movable body control device and time-varying output circuit

[0001] The present invention relates to a movable body control method, a movable body control device, and a time-varying output circuit.This application claims priority to Japanese Patent Applications Nos. 2024-018031 and 2024-018032, filed February 8, 2024, the contents of which are incorporated herein by reference.

[0002] Robotic hands with fingers are controlled by detecting the force acting on an object from the fingertips using, for example, a six-axis sensor attached to the fingertips or a contact sensor attached to the finger pads, and controlling the force acting on the object so that it matches the target acting force (see, for example, Patent Document 1).

[0003] When grasping an object with fingers, depending on the shape of the object, in addition to the point contact state between the object and the fingertip, grasping control is required in both the rolling contact state where the object is grasped while rolling (the object is rolling), and the sliding contact state where the object slides. In the point contact state and the rolling contact state, the posture of the grasped object can be determined from contact information (contact force and contact point) alone.

[0004] On the other hand, in a sliding contact state, contact information alone is insufficient for posture estimation. Therefore, in order to suppress the sliding contact state, the physical parameters must be known. Alternatively, to suppress the sliding contact state, a control method that does not take the sliding situation into account has been used.

[0005] Patent No. 5829103

[0006] In the prior art, control of a sliding contact state required estimating the slip parameters and completing the physical parameters of the controlled object, which was a difficult task. In this way, in the prior art, it was necessary to estimate the slip using some kind of estimator, which was difficult.

[0007] Furthermore, even if attempts were made to use the time change in force for control that takes slippage into account, conventional technology, for example, when using an event camera, could only acquire changes in the image, and was unable to directly acquire the time change in force. For this reason, conventional technology has made it difficult to achieve stable grip in sliding contact that involves slippage.

[0008] The aspects of the present invention have been made in consideration of the above-mentioned problems, and aim to provide a movable body control method that can easily suppress and stabilize slippage using a force sensor without identifying or estimating physical parameters, as well as a movable body control device and a time-varying output circuit that can directly acquire the time-varying value of force.

[0009] In order to solve the above problems, the present invention employs the following aspects: (1) A movable body control method according to one aspect of the present invention is a method for controlling at least one movable part and a contacting object in contact with the movable part, wherein a control device controls the movable part or the contacting object by applying a force to a contact surface with a plurality of the movable parts, and when calculating a contact force generated on the contact surface based on energy, the total energy of the entire movable part or the contacting object is considered to be the sum of stored energy and damping energy and does not increase, and an external force term in the stored energy term includes information about slippage between the movable part and the contacting object relative to the contact surface, and the calculation is performed so that the external force term is integrable.

[0010] (2) A movable body control method according to one aspect of the present invention is a control method for manipulating a contact object using a hand with a plurality of finger portions, wherein the finger portions are movable portions, a control device controls the position and posture of the contact object by applying force using the plurality of finger portions, and when calculating the contact force generated on the contact surface between the finger portions and the contact object based on energy, the energy of the entire movable portion is the sum of stored energy and damping energy and does not increase, and an external force term in the stored energy term includes information on slippage between the finger portions and the contact object on the contact surface, and the calculation is performed so that the external force term is integrable.

[0011] (3) In the above aspect (1) or (2), the external force term is a sum of time-differentiated contact forces of the respective movable parts with respect to the contact object, expressed by the following equation:

[0012]

[0013] f is the force at the contact point, and p ・may be the change in position of the contact point.

[0014] (4) In any one of the above aspects (1) to (3), the command value of the time derivative of the energy of the movable part is expressed by the following equation:

[0015]

[0016] k ｆ may be the gain and f the force at the contact point.

[0017] (5) In the above aspect (1) or (2), the control device issues a force command E ・ ｃｍｄ By offsetting using the following equation, the change in slip is extracted and controlled.

[0018]

[0019] f ｃｍｄ is the target force value, and f ａｃｔ may be slippage information.

[0020] (6) In the above aspect (1) or (2), the control device calculates a force command E to the movable part that is correlated with a Lyapunov function using the following equation: ・ ｃｍｄ The gain is increased or decreased based on the change in

[0021]

[0022] k ｆ , k ｅ Each of them may be a gain.

[0023] (7) A control device for a movable body according to one aspect of the present invention is a control device for a movable body that controls at least one movable part and a contacting object that comes into contact with the movable part, or the movable part itself, and includes: a control command generation unit that controls the movable part or the contacting object by applying force to a contact surface using a plurality of the movable parts; and a contact force calculation unit that, when calculating the contact force generated on the contact surface based on energy, calculates the contact force by assuming that the total energy of the entire movable part or the contacting object is the sum of stored energy and damping energy and does not increase, and the contact force calculation unit calculates the contact force such that an external force term in the stored energy term includes information about the sliding of the movable part and the contacting object relative to the contact surface, and the external force term is integrable.

[0024] (8) A control device for a movable body according to one aspect of the present invention is a control device that operates a contact object using a hand with a plurality of finger portions, and includes: a control command generation unit that controls the position and posture of the contact object by applying force using the plurality of finger portions; a contact force calculation unit that, when calculating the contact force generated on the contact surface between the finger portions and the contact object based on energy, calculates the contact force by assuming that the energy of the entire movable portion is the sum of stored energy and damping energy and does not increase; and an external force term in the stored energy term of the contact force calculation unit includes information on slippage on the contact surface between the finger portions and the contact object, and calculates the external force term so that it is integrable.

[0025] (9) A time-varying output circuit according to one aspect of the present invention is a time-varying output circuit including a differential amplifier circuit that receives as input a value obtained by a sensor that acquires contact force with a target object and a current change value due to inductance in the value of the sensor, and outputs a time-varying value of the contact force with the target object.

[0026] (10) In the above aspect (9), one end of the sensor may be connected to a power supply voltage, one end of the inductance may be connected to the other end of the sensor and the positive input terminal of the differential amplifier circuit, and the other end may be connected to the negative input terminal of the differential amplifier circuit and grounded, and the differential amplifier circuit may output a time change value of a force obtained by multiplying the difference between the value input to the positive input terminal and the current change value input to the negative input terminal by the gain of the differential amplifier circuit.

[0027] (11) In the above aspect (9), a resistor and a buffer circuit may be further provided, and the input of the current change value due to the inductance of the sensor value may be grounded via the resistor and connected to the input of the buffer circuit, and the buffer circuit may output the contact force with the target object.

[0028] (12) In the above aspect (11), one end of the sensor is connected to a power supply voltage, one end of the inductance is connected to the other end of the sensor and the positive input terminal of the differential amplifier circuit, and the other end is connected to the negative input terminal of the differential amplifier circuit, one end of the resistor, and a first input terminal of the buffer circuit, the other end of the resistor is grounded, the differential amplifier circuit outputs a time-varying value of force obtained by multiplying the difference between the value input to the positive input terminal and the current change value input to the negative input terminal by the gain of the differential amplifier circuit, and the buffer circuit may have a second input terminal and an output terminal connected to output the contact force with the target object.

[0029] (13) In any one of the above aspects (9) to (11), the sensor may be a sensor whose resistance changes in response to an applied force.

[0030] According to the above aspects (1) to (8), slippage can be easily suppressed and stabilized using a force sensor without identifying or estimating physical parameters.

[0031] According to the above aspects (9) to (13), it is possible to directly obtain the time change value of the force.

[0032] 1 is a diagram for explaining point contact and rolling contact without slippage.

[0033] FIG. 1 is an image diagram of a target object and contact points of the fingers of a hand in sliding contact, forces acting from the fingertips to the target object, and forces acting on the target object.

[0034] FIG. 2 is a diagram illustrating models and high-speed conditions for each contact state.

[0035] FIG. 3 is a model for explaining problems with conventional methods.

[0036] FIG. 4 is a diagram illustrating the relationship between position and energy, explaining the problems with conventional methods.

[0037] FIG. 5 is a diagram illustrating an example of the relationship between each energy and position in grasping in the first embodiment.

[0038] FIG. 6 is a diagram illustrating an example of the configuration of a control system according to the first embodiment.

[0039] FIG. 7 is a side view of the hand during grasping.

[0040] FIG. 8 is an example of a grasping operation using point contact and rolling contact in the conventional method.

[0041] FIG. 9 is a simulation result.

[0042] FIG. 10 is a diagram illustrating the change in the direction of force over time and the change in velocity at the contact point over time in a grasping operation using point contact and rolling contact in the conventional method.

[0043] FIG. 11 is an example of a grasping operation using point contact, rolling contact, and sliding contact in the first embodiment.

[0044] FIG. 12 is a diagram illustrating the change in the direction of force over time and the change in velocity at the contact point over time in a grasping operation using point contact, rolling contact, and sliding contact in the first embodiment. 1 is a diagram showing an example of changes in actual acceleration, actual force, and actual power with respect to time during control by a conventional method and during control by the first embodiment. FIG. 1 is a flowchart of processing by a control system according to an embodiment. FIG. 2 is a diagram for explaining problems with the conventional technique. FIG. 3 is a diagram showing an example of a gripping state when a force command is offset and the gain is increased or decreased in an embodiment. FIG. 4 is a diagram showing example simulation results when controlled by a conventional technique and a first technique of this embodiment. FIG. 5 is a diagram showing example simulation results when controlled by a conventional technique and a second technique of this embodiment. FIG. 6 is a flowchart of processing by a control system according to a second embodiment. FIG. 7 is a flowchart of processing by a control system according to a third embodiment. FIG. 8 is a diagram for explaining point contact and rolling contact when no slipping occurs. FIG. 9 is an image diagram of a target object in sliding contact, the contact points of the fingers of the end effector, the forces acting from the fingertips to the target object, and the forces acting on the target object. FIG. 10 is a diagram showing models and high-speed conditions for each contact state. FIG. 11 is a model for explaining problems with the conventional method. FIG. 12 is a diagram showing the relationship between position and energy, which explains the problems with the conventional method. FIG. 13 is a diagram showing an example of a time-varying output circuit according to an embodiment.1 is a diagram illustrating an example of the configuration of a control system including a time-varying output circuit; FIG. 1 is a diagram illustrating an example of a sensor output; FIG. 1 is a diagram illustrating an example of a change in force applied to a sensor, a force differential value, and a change in the output of a differential amplifier circuit; FIG. 2 is a side view of a hand during grasping; FIG. 2 is an example of a grasping operation using point contact and rolling contact according to a conventional method; FIG. 3 is a diagram illustrating a change in the direction of force over time and a change in velocity at the contact point over time in a grasping operation using point contact and rolling contact according to a conventional method; FIG. 4 is an example of a change in the direction of force over time and a change in force differential value over time during control using a conventional method; FIG. 4 is an example of a grasping operation using point contact, rolling contact, and sliding contact according to an embodiment; FIG. 5 is a diagram illustrating a change in the direction of force over time and a change in velocity at the contact point over time during control using a method according to an embodiment; and FIG. 6 is a diagram illustrating an example of a control operation using conventional technology and a control operation using a modified example of this embodiment in which the force command is offset and the gain is increased or decreased. 10 is a diagram illustrating a modified example of a time-varying output circuit according to an embodiment.

[0033] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings used in the following description, the scale of each component has been appropriately changed so that each component can be recognized. In all drawings used to explain the embodiments, components having the same function are designated by the same reference numerals, and repeated explanations will be omitted. In addition, "based on XX" in this application means "based on at least XX" and includes cases where the component is based on other elements in addition to XX. Furthermore, "based on XX" is not limited to cases where XX is used directly, but also includes cases where the component is based on XX after calculation or processing. "XX" is any element (for example, any information).

[0034] [Overview] First, the terms "point contact," "rolling contact," and "sliding contact" used in this embodiment will be explained. FIG. 1 is a diagram for explaining point contact and rolling contact where no sliding occurs. The diagrams indicated by symbols g11 and g12 are diagrams of examples of point contact states. The diagram indicated by symbol g12 is an enlarged view of the gripping state indicated by symbol g11. The arrow g13 shows an image of the force acting from the fingertip to the target object (contact object) and its direction. The diagram indicated by symbol g21 is a diagram showing an example of a rolling contact state. The arrow g22 shows an image of the fingertip rolling on the target object.

[0035] Conventional control methods stabilize the dynamics of a target object based on its estimated CoM (weight). Grasping control requires accurate joint forces that are non-slip, but this is difficult. The prerequisite for control of point and rolling contact is that point contact is equal to rolling contact, and the posture of the grasped object is estimated and controlled solely based on contact information between the fingertip's contact point and the target object's contact point.

[0036] Figure 2 is an image diagram of the contact points between the target object obj and the hand's fingers fin (fin-1 to fin-3) in sliding contact, as well as the forces f1 to f3 acting from the fingertips to the target object obj and the forces f5 to f6 acting on the target object obj. Note that while Figure 2 shows an example with three fingers, the number of fingers can be two or more. The prerequisite for control that also uses sliding contact is that point contact ∈ rolling contact ∈ sliding contact, and contact information alone is insufficient to estimate the posture of the target object, making stable grasp control difficult.

[0037] The hand 2 may be remotely controlled by an operator wearing a head-mounted display, data gloves, etc. However, the operation control is not limited to remote control, and the operator may visually check the hand 2 and the target object, or the hand 2 may be automatically controlled.

[0038] FIG. 3 shows models and constraints for each contact state. The diagram indicated by reference numeral g31 is an image diagram of the contact point between the target object obj and the finger fin of the hand 2, the force acting from the fingertip to the target object obj, and the force acting on the target object obj. The diagram indicated by reference numeral g32 is an example model of the finger fin and the target object obj when controlled in point contact. The constraint conditions in this case are no rolling and no sliding. Conventional control methods could only handle two or more points of contact. The diagram indicated by reference numeral g33 is an example model of the finger fin and the target object obj when controlled in rolling contact. The constraint conditions in this case are rolling but no sliding. This was also possible with conventional control methods. The diagram indicated by reference numeral g34 is an example model of the finger fin and the target object obj when controlled in slipping contact. The constraint conditions in this case are rolling and sliding. Conventional control methods could not cope with this.

[0039] Note that the gripping unit in this embodiment is controlled without using images captured by the imaging device. Also, in this embodiment, grip stabilization control can be performed without using the coefficient of friction between the target object obj and the fingers, etc.

[0040] <First embodiment> A control method of this embodiment will be described. First, the problems of the conventional method will be described. FIG. 4 is a model for explaining the problems of the conventional method. FIG. 5 is a diagram showing the relationship between position and energy, which explains the problems of the conventional method. In FIG. 5, the horizontal axis represents position and the vertical axis represents energy. In the conventional method, all the energy E generated by the finger ａｌｌ is expressed as the dissipative energy E ｄｉｓｓｐａｔｕｖｅ and the conserved energy E ｃｏｓｅｒｖｅｄ It is expressed in terms of

[0041]

[0042] Conserved energy E ｃｏｓｅｒｖｅｄ The term is expressed as the kinetic energy E ｋｉｎｅｔｉｃ and the potential energy E ｐｏｔｅｎｔｉａｌ It is expressed in terms of

[0043]

[0044] In the conventional method, the conserved energy E ｐｏｔｅｎｔｉａｌ The problem is that it is a function dependent on position and orientation, as shown in Figure 5, and it can only control point contact and rolling contact, but cannot control sliding contact.

[0045] In contrast, in this embodiment, the stored energy E ｐｏｔｅｎｔｉａｌ The energy due to gravity E ｇｒａｃｉｔｙ and external force Ｅａｄｄ By expressing it in terms of

[0046]

[0047] In this way, in this embodiment, the external force E ａｄｄ The term includes slip information, making the system integrable, i.e., conservative. The external force E that satisfies this condition ａｄｄ An example of the formula is the following formula (4). In this embodiment, formula (4) is defined as "f ｔｉｐ " and "f" and simplified to "p ・ ｔｉｐ " to "p ・ " and simplified it to E ａｄｄ = ∫(f p ・ ) dt. This allows us to implicitly understand the shape of the potential function and achieve Lyapunov stability.

[0048]

[0049] Equation (4) is a time integral. The time integral value of the force often contains slip information. In the embodiment, f ｔｉｐ is the force of the fingertip at the contact point, and p ｔｉｐ is the position of the contact point (the position of the fingertip). ・ With f ・ ｔｉｐ is the change in fingertip force, and p ・ ｔｉｐ is the change in the position of the contact point. ａｄｄ The slip information is included in the external force term E ａｄｄ To satisfy the condition that p is integrable (the system is a conservative system), ・ ｔｉｐis, for example, the following equation (5).

[0050]

[0051] Equation (5) is ａｄｄ = ∫(f p ・ ) dt, equation (4) can also be expressed as the following equation (6).

[0052]

[0053] Furthermore, the stability of an autonomous system can be divided into Lyapunov stability and near-near stability. For any s, if δ exists and if ||x(0)|| < δ, then if ||x(t)|| < ε, then the equilibrium point x = 0 is Lyapunov stable. In other words, when a trajectory that starts from near an equilibrium point of a dynamical system continues to remain near the equilibrium point, the equilibrium point is said to be Lyapunov stable.

[0054] [Method for stabilizing grasping of an unknown object] Next, an example of a method for including slippage information in the external force term will be described. Fig. 6 is a diagram showing an example of the relationship between each energy and position of the grasping in this embodiment. The horizontal axis is position, and the vertical axis is energy. Each line represents E with respect to position. ａｌｌ , E ｋｉｎｅｔｉｃ , E ｐｏｔｅｎｔｉａｌ , and E ａｄｄ is.

[0055] As shown in Figure 6, E ａｌｌ and E ｐｏｔｅｎｔｉａｌ and E ａｄｄ draws an upward curve toward the center position, and E ｋｉｎｅｔｉｃ The curve moves downwards towards the center. ａｌｌ is known, and E ｋｉｎｅｔｉｃ is unknown, and E ｐｏｔｅｎｔｉａｌ is unknown, and E ａｄｄ is partially known. The Lyapunov function is the potential E ｐｏｔｅｎｔｉａｌ , and E ａｄｄ Therefore, E ｐｏｔｅｎｔｉａｌ , and E ａｄｄ If the sum of E and E is not convex downward, it will not be stable. ａｄｄ Increase the gain of (E ａｄｄ(only modify the curve) so that it is convex downward.

[0056] Here, if E ａｄｄ If is based on potential, then E ａｄｄ The change in E ｐｏｔｅｎｔｉａｌ changes at the same time. ａｄｄ If is based on potential, for example, E ａｄｄ = h(x) (x is the position), and E ａｄｄ Is E ｐｏｔｅｎｔｉａｌ It becomes a convex curve in accordance with E ａｄｄ If is based on kinetics, then E ａｄｄ The change in E ｋｉｎｅｔｉｃと Changes at the same time. ａｄｄ If is based on kinetics, E ａｄｄ Is E ｋｉｎｅｔｉｃ It forms a downward convex curve.

[0057] In this way, at least the shape of Eadd is known. AｌｌPｏｔｅｎｔｉａｌ is expressed as the following equation (7).

[0058]

[0059] In addition, the potential function E AｌｌPｏｔｅｎｔｉａｌ is required to be expressed by the following equation (8), and E ａｄｄ is required to be the following equation (9).

[0060]

[0061]

[0062] In this way, E ａｄｄ By observing the change in the total energy E, it is possible to know whether the equation (8) is negative. ａｌｌ is a conservative system.

[0063] The control device 3 controls the movable parts or contacting objects (grasped objects, target objects) by applying forces to the contact surfaces using multiple movable parts (e.g., fingers 21). When calculating the contact force acting on the contact surfaces based on energy, the control device 3 assumes that the total energy of the entire movable parts or contacting objects is the sum of stored energy and damping energy, and does not increase. The control device 3 calculates the external force term in the stored energy term so that it includes information about slippage between the movable parts and contacting objects on the contact surfaces and is integrable. The movable parts may be, for example, a motorcycle. In this case, the contacting object is, for example, the floor.

[0064] [Configuration Example of Control System] Next, a configuration example of the control system according to this embodiment will be described. FIG. 7 is a diagram showing a configuration example of the control system according to this embodiment. As shown in FIG. 7, the control system 1 includes, for example, a hand 2 and a control device 3. The hand 2 includes, for example, a plurality of fingers 21 (21-1, ..., 21-n) (n is an integer of two or more) (movable portion), a plurality of actuators 22 (22-1, ..., 22-n), a plurality of sensors 23 (23-1, ..., 23-n), and a base 24. The control device 3 includes, for example, an acquisition unit 31, a contact force calculation unit 32, a control value generation unit 33, a drive circuit 34, an output unit 35, and a storage unit 36.

[0065] The hand 2 is, for example, an end effector or a gripper. The hand 2 has at least two fingers 21. Alternatively, each hand 2 may have at least one finger. The hand 2 grasps, for example, a target object in accordance with the control of the control device 3. The hand 2 may be one arm or both arms, and may have an arm and a body. The hand 2 may also be included in, for example, a robot having a body. The hand 2 and the control device 3 are connected to each other via a wired or wireless network NW.

[0066] The fingers 21 (21-1, . . . , 21-n) have joints.

[0067] The actuators 22 (22-1, . . . , 22-n) are attached to the joints of the finger portion 21 and the joints between the finger portion 21 and the base portion 24. The actuators 22 may include a drive circuit .

[0068] The sensors 23 (23-1, ..., 23-n) are, for example, finger pressure sensors attached to the pads of the fingers 21 or six-axis sensors attached indirectly. The six-axis sensor detects forces along three axes (x, y, z) and moments along three axes (α, β, γ).

[0069] The base 24 is the part to which the finger 21 is attached.

[0070] The control device 3 uses information acquired from the hand 2 to control the hand 2 and a contact object (for example, a grasped object or a floor surface) that comes into contact with the finger portions 21 of the hand 2 .

[0071] The acquisition unit 31 acquires detection information detected by the sensor 23 of the hand 2 .

[0072] The contact force calculation unit 32 calculates the contact force so that the external force term in the conserved energy term includes information about the slippage between the finger 21 and the contact surface of the contact object, and the external force term is integrable, as in the above-mentioned equation.

[0073] The control value generation unit 33 generates a control value for the hand 2 using the contact force calculated by the contact force calculation unit 32. If the control device 3 includes a drive circuit 34, the control value generation unit 33 outputs the generated control value to the drive circuit 34. If the hand 2 includes a drive circuit 34, the control value generation unit 33 outputs the generated control value to the output unit 35.

[0074] The drive circuit 34 outputs a drive signal for driving the corresponding actuator 22 to the output unit 35 in accordance with the control value generated by the control value generation unit 33. The drive circuit 34 may be provided in the hand 2.

[0075] When the control device 3 includes the drive circuit 34, the output unit 35 outputs the control value generated by the control value generation unit 33 to the hand 2. When the hand 2 includes the drive circuit 34, the output unit 35 outputs the drive signal generated by the drive circuit 34 to the hand 2.

[0076] The storage unit 36 ​​stores programs, thresholds, mathematical expressions, identification information for identifying the hand 2, and the like required for control.

[0077] 7 is merely an example, and the present invention is not limited to this. Other components may be included. For example, the hand 2 and the control device 3 each include a power supply unit.

[0078] [Example of a Grasping Operation Using a Conventional Method and an Example of a Grasping Operation Using the Present Embodiment] Next, an example of a grasping operation using point contact and rolling contact using a conventional method and an example of a grasping operation using point contact, rolling contact, and sliding contact using the present embodiment will be described. FIG. 8 is a side view of a hand during grasping. The example in FIG. 8 is an image diagram showing a hand 2 attempting to stably grasp a target object obj with two fingers 21 (21-1, 21-2). The target object obj is an object whose top diameter is shorter than its bottom diameter, such as a cup placed with its mouth facing downward. Circles 25 (25-1-1, 25-1-2, 25-2-1, 25-2-2) represent joints. Points g101 and g102 represent contact points between the fingers 21 and the target object obj. A line g103 indicates a tangent direction to the target object obj, a line g104 indicates a normal direction to the target object obj, and a dashed arrow g105 indicates a force generated from the contact points (points g101 and g102) on the finger portion 21. Note that the direction of the arrows may be reversed.

[0079] The methods for confirming the grasping operation using point contact and rolling contact in the conventional method and the grasping operation using point contact, rolling contact, and sliding contact in this embodiment are as follows: (A) A static grasp is performed while a specific internal force (5 N) is applied. (B) An input (disturbance) that exceeds the static friction region is applied. The criteria for determining whether the grasp is successful or unsuccessful are as follows: (Success) After exceeding the static friction region, the object returns to the static friction region. (Failure) After exceeding the static friction region, the object never returns to the static friction region.

[0080] Note that the conventional grip control method uses, for example, compliance control. For this reason, a rolling constraint is set as a prerequisite, and control is performed at the contact point on the manipulated object side. In the following explanation, the subscript cmd indicates the target value of control (target value of angle and position) sent to the actuator. The target value of force in the conventional method, f ｃｍｄ is expressed by the following equation (10): ｒｅｆ and p ａｃｔ Each of these is a fixed value. ｐ is the gain, and p ｒｅ f is the target value of the finger position, the position of the contact point, and p ａｃｔ is the position of the contact point between the fingertip and the target object. The stability is Lyapunov stable, and the target energy E ｃｍｄ is expressed by the following equation (11).

[0081]

[0082]

[0083] FIG. 9 shows an example of a grasping operation using point contact and rolling contact according to a conventional method. Note that FIG. 9 shows simulation results. Reference symbol g201 indicates the start of grasping, reference symbol g202 indicates a state in which force is applied, and reference symbol g203 indicates a state in which the target object obj has slipped off the finger 21. Reference symbol 211 indicates the force and each axis generated in each finger 21 indicated by reference symbol 201. Reference symbol 212 indicates the force and each axis generated in each finger 21 indicated by reference symbol 202. Reference symbol 213 indicates the force and each axis generated in each finger 21 indicated by reference symbol 203. Note that in reference symbols g201 to g203 and g211 to g213, each line indicates the axial direction, the force acting from the fingertip to the target object, etc. In the grasping operation using point contact and rolling contact according to a conventional method, the target object obj slips off the finger 21 and is not retained by the finger 21, as indicated by reference symbol g203.

[0084] Figure 10 shows the change in the direction of force over time and the change in velocity at the contact point over time in a gripping operation using point contact and rolling contact according to a conventional method. Note that Figure 10 is a simulation result. The horizontal axis of symbol g230 is time (sec), and the vertical axis is the angle θ of the force generated at the contact point. The angle θ is the angle between the normal direction of the target object obj and the perpendicular line, as shown in Figure 8. The horizontal axis of symbol g240 is time (sec), and the vertical axis is the velocity (m / s) generated at the contact point.

[0085] Reference symbol g220 indicates the state of the finger portion 21. Reference symbol g221 indicates the start of grasping, reference symbol g222 indicates the state in which force is applied, and reference symbol g223 indicates the state in which the target object obj has slipped off the finger portion 21.

[0086] Reference symbol g230 indicates the change in the direction of the force over time. Region g231 indicates a zone where slippage occurs but the frictional force is not exceeded and grip is maintained (static friction region), region g232 indicates a zone where the frictional force exceeds the gripping force, and region g233 is an error zone. The angle θ indicated by arrow g234 indicates that gripping is maintained in the gripping state indicated by reference symbol g221. The angle θ indicated by arrow 235 indicates that the frictional force has been exceeded and the angle is changing rapidly. The angle θ indicated by arrow 236 indicates that the target object obj has slipped off the finger 21 and fallen, preventing the target object obj from returning to the finger 21.

[0087] Symbol g240 represents the change in velocity at the contact point over time. Between 0.8 and 1.0 seconds, as shown by symbol g230, the angle of the force changes suddenly, indicating that slippage is occurring.

[0088] As described above, with the control of the conventional method, the robot did not return to the static friction region after going beyond it, so it was unable to maintain grip (failure) and was unable to achieve stable grip beyond the static friction region. Note that with the control of the conventional method, the stable region (maximum target internal force - minimum target internal force) was approximately 0.2 (N).

[0089] FIG. 11 shows an example of a grasping operation using point contact, rolling contact, and sliding contact according to this embodiment. Note that FIG. 11 shows simulation results. Reference symbol g301 indicates the start of grasping, reference symbol g302 indicates a state in which force is applied, and reference symbol g303 indicates a state in which the finger units 21 are maintaining their grip on the target object obj. Reference symbol 311 indicates the force and each axis generated in each finger unit 21 indicated by reference symbol 301. Reference symbol 312 indicates the force and each axis generated in each finger unit 21 indicated by reference symbol 302. Reference symbol 313 indicates the force and each axis generated in each finger unit 21 indicated by reference symbol 303. Note that in reference symbols g301 to g303 and g311 to g313, each line indicates the axial direction, the force acting from the fingertip to the target object, etc. In the grasping operation using point contact, rolling contact, and sliding contact according to this embodiment, the finger units 21 are able to maintain their grip on the target object obj, as indicated by reference symbol g303.

[0090] Figure 12 shows the change in the direction of force over time and the change in velocity at the contact point over time in a gripping operation using point contact, rolling contact, and sliding contact in this embodiment. Note that Figure 12 is a simulation result. The horizontal axis of symbol g330 is time (sec), and the vertical axis is the angle θ of the force generated at the contact point. The horizontal axis of symbol g340 is time (sec), and the vertical axis is the velocity (m / s) generated at the contact point.

[0091] Reference symbol g320 indicates the state of the finger portion 21. Reference symbol g321 indicates the start of grasping, reference symbol g322 indicates the state in which force is being applied, and reference symbol g323 indicates the state in which the target object obj is able to be maintained in a grasp without slipping off the finger portion 21.

[0092] Reference symbol g330 indicates the change in the direction of the force with respect to time. Region g331 is a zone (static friction region) where slippage occurs but the frictional force is not exceeded and gripping is maintained, and region g332 is a zone where the frictional force exceeds the gripping force. The angle θ indicated by arrow g334 indicates that gripping is maintained in the gripping state indicated by reference symbol g321. The angle θ indicated by arrow 335 indicates that the frictional force has been exceeded and the angle is changing rapidly. The angle θ indicated by arrow 336 indicates that the target object obj has returned to the static friction region without slipping off the finger 21, and that the target object obj has returned to the finger 21.

[0093] Symbol g340 represents the change in velocity at the contact point with respect to time. Between 0.4 and 0.6 seconds, as shown by symbols g330 and g340, the angle of the force changes suddenly, indicating that slippage is occurring.

[0094] In this way, with the control of this embodiment, after going beyond the static friction region, the robot returned to the static friction region, maintaining the grip (success), and achieving stable grip beyond the static friction region. Note that with the control of this embodiment, the stable region (maximum target internal force - minimum target internal force) was approximately 4.0 (N), which was approximately 20 times larger than the control of the conventional method.

[0095] 13 is a diagram showing an example of changes in actual acceleration, actual force, and actual power with respect to time when controlled by a conventional method and when controlled by this embodiment. Note that FIG. 13 shows only the z direction of the contact point.

[0096] Graph g400 shows the change in actual acceleration over time, with the horizontal axis representing time (sec) and the vertical axis representing actual acceleration (m / s). Line g401 represents control under the conventional method, and line g402 represents control under the present embodiment. Graph g410 shows the change in actual acceleration over time, with the horizontal axis representing time (sec) and the vertical axis representing force (N). Line g411 represents control under the conventional method, and line g412 represents control under the present embodiment.

[0097] As shown in graphs g400 and g410, when using the conventional method, after a slip occurs as indicated by arrow g403, the target object is dropped as indicated by arrow g404. In contrast, when using the control method of this embodiment, even after a slip occurs as indicated by arrow g405, the target object is not dropped and is maintained in grip as indicated by arrow g406.

[0098] The graph g420 shows the change in actual power (J / s) over time, with the horizontal axis representing time (sec) and the vertical axis representing actual power (J / s). The line g421 represents the change in command power E ・ ｃｍｄ , line g422 is the actual power of control (Actual Power) E ・ ａｃｔ In addition, the actual power E・ ａｃｔ The vertical axis of the graph g420 is magnified by 500 times. The movement of the force during control in this embodiment is such that the finger 21 moves and tries to do work in the upward direction of the z-axis (actual power E ・ ａｃｔ ) with negative power correction (command power E ・ ｃｍｄ ) is inserted to return it.

[0099] As a result, according to the control method of this embodiment, an appropriate command to grasp (internal force) is issued using the detection value of the sensor without using a camera, and stable grasping is possible even if the target object obj unintentionally slips from the finger unit 21. Furthermore, according to this embodiment, slippage can be easily suppressed and stabilized using a sensor that can indirectly or directly measure the time derivative of force without identifying or estimating physical parameters.

[0100] [Example of Processing Procedure] Next, an example of processing procedure of the control system 1 of this embodiment will be described. Fig. 14 is a flowchart of processing of the control system according to this embodiment.

[0101] (Step S1 ) The acquisition unit 31 acquires a detection value from the sensor 23 of the hand 2 .

[0102] (Step S2) The contact force calculation unit 32 extracts a contact point using the acquired detection value, and determines the position of the extracted contact point.

[0103] (Step S3) The contact force calculation unit 32 calculates the contact force at the determined contact point, including an external force term. Note that when calculating the contact force acting on the contact surface based on energy, the contact force calculation unit 32 assumes that the total energy of the entire finger 21 or the contacting object is the sum of stored energy and damping energy and does not increase. Note that the contact force calculation unit 32 calculates the external force term in the stored energy term so that it includes information about the sliding between the finger 21 and the contacting object on the contact surface and so that the force term is integrable.

[0104] (Step S4) The control value generating unit 33 generates a control value for controlling the hand 2 using the calculated contact force at the contact point.

[0105] (Step S5) The output unit 35 outputs the generated control value to the hand 2. As a result, the control device 3 applies force to the contact surface with the multiple fingers 21 (movable parts), thereby controlling the movable parts or the contact object.

[0106] Second Embodiment Next, a further improvement of the above-described embodiment will be described. FIG. 15 is a diagram illustrating problems with the prior art. As shown in FIG. 15, for example, a target object placed on a desk is pinched and grasped with two fingers. The target object obj is, for example, an irregularly shaped object, such as a small rock. Reference symbol g501 shows how the hand 2 grasps the target object obj. In the example of FIG. 15, the hand 2 includes, for example, three or more fingers 21. Reference symbols g511 to g513 show a state in which the fingertip 21 begins to grasp the target object obj from the left and right, applies force from the left and right, and then fails and drops the object as shown by reference symbol g513. Note that in reference symbols g511 to g513, each line indicates an axial direction, a force acting from the fingertip on the target object, etc.

[0107] Symbol g520 represents the relationship of the Lyapunov function to the command force. The range of symbol g521 is the static friction region (friction that occurs on a stationary object). The range of symbol g522 is the dynamic friction region (friction that occurs on a moving object). Symbol g523 is the sliding boundary. The dashed line g524 represents the relationship of the Lyapunov function to the command force in the static friction region. Lines g525 and g526 represent the relationship of the Lyapunov function to the command force in the dynamic friction region.

[0108] In this prior art, for example, compliance control causes the object to be pulled into the minimum point g527 of the boundary line g523 between the static friction region and the dynamic friction region, as shown by the symbol g520, and stabilize. That is, the object tends to slip slightly, as shown by the line g524, but stabilizes at the boundary line g523 and cannot return. The problem with this prior art is that the object's motion is stable due to stabilization at the slip boundary line g523, but the object's motion is violent due to excessive control input.

[0109] In the prior art, slippage information f ・ ａｃｔ Calculate the force command from the energy expression including ・ ｃｍｄ is expressed in a non-slip form as in the following equation (12). ・ ｃｍｄ is the above-mentioned E ａｄｄ Corresponds to.

[0110]

[0111] Then, the target force instruction f ｃｍｄ is expressed as in the following equation (13): In equation (13), PI represents PI (Proportional-Integral) control.

[0112]

[0113] In contrast to this, in this embodiment, in order to extract changes during slippage, the control value generator 33 offsets the force command as shown in the following equations (14) and (15). In this way, in this embodiment, since the error component is subtracted, only changes during slippage can be extracted and controlled.

[0114]

[0115]

[0116] The offset is the target value of the change in energy E ・ ｃｍｄ f in equation (12) ａｃｔ and f ・ ａｃｔ From this, f is obtained as shown in equation (15). ｅｒｒｏｒ and f ・ ｅｒｒｏｒ and replace with f ｅｒｒｏｒ f as in equation (12). ｃｍｄ and f ａｃｔ In the control of the conventional technique using equation (12), ａｃｔ 15, the curve converges to the minimum value g527 as shown by the line g524 in FIG. ｃｍｄ From f ａｃｔBy offsetting (drawing) the line g574, the line g574 can be controlled to be the bottom, instead of converging at the boundary line as in the case of lines g574 and g575 in FIG.

[0117] Furthermore, in this embodiment, in order to make the change gentler, the control value generating unit 33 generates a command E ・ ｃｍｄ From the change in the gain k ｆ is updated by increasing or decreasing k ｅ is the gain and is a fixed value.

[0118]

[0119] FIG. 16 shows an example of a gripping state achieved by control in which the force command is offset and the gain is increased or decreased in this embodiment. The target object obj is, for example, an irregularly shaped object, such as a small rock. Reference symbols g551 to g554 represent states in which the fingertip 21 begins to grip the target object obj from the left and right, and continues to grip the object without dropping it, even when force is applied from both sides, as shown by reference symbol g554. Note that in reference symbols g551 to g554, each line represents the axial direction, the force acting on the target object from the fingertip, etc. Reference symbol g570 represents the relationship between the command force and the Lyapunov function. The range indicated by reference symbol g571 is the static friction region. The range indicated by reference symbol g573 is the dynamic friction region. Reference symbol g573 represents the sliding boundary. The dashed line g574 represents the relationship between the command force and the Lyapunov function in the static friction region. Line g575 is the relationship of the Lyapunov function to the command force in the dynamic friction region.

[0120] In the control of this embodiment, when the boundary between the static friction region and the dynamic friction region is crossed, the change is controlled gradually as indicated by arrow g576, making it possible to continue holding the grip, for example, as indicated by symbol g554. As a result, even at the boundary line position, the change is gradual as indicated by arrow g576, rather than a minimum value represented by a steeply inclined line as in FIG. 15. In this embodiment, control is performed to remain in the static friction region where a stable grip can be maintained. In this embodiment, this control solves the problems of the prior art.

[0121] Furthermore, examples of simulation results for grasping using only the first technique of this embodiment and grasping using only the second technique will be described. The first technique is the above-mentioned force conversion (=f ｃｍｄ The second method is the above-mentioned method of dynamically adjusting the gain k.

[0122] 17 shows example simulation results for control using a conventional technique and control using the first technique of this embodiment. The target object obj is an image of an object such as a truncated pyramid. In the images of symbols g600, g611, g612, g621, and g622, each line indicates the axial direction, the force acting from the fingertip to the target object, and the like.

[0123] The image with reference numeral g600 is an example of the state at the start of control. The images with reference numerals g611 and g612 are examples of states controlled by offsetting the force change using the conventional technique. Even when a truncated pyramid object is grasped as in the image with reference numeral g612, the conventional technique fails to hold the target object and causes it to drop. The images with reference numerals g621 and g622 are examples of states controlled by offsetting the force change using the first technique. On the other hand, even when a truncated pyramid object is grasped as in the image with reference numeral g622, the target object can be held without dropping using only the first technique of this embodiment.

[0124] 18 shows example simulation results for control using the conventional technique and control using the second technique of this embodiment. The target object obj is an image of an object such as a truncated pyramid. In the images of symbols g650, g661, g662, g671, and g672, each line indicates the axial direction, the force acting from the fingertip to the target object, etc.

[0125] The image with reference numeral g650 is an example of the state at the start of control. The images with reference numerals g661 and g662 are examples of the state when control is performed by dynamically adjusting the gain using the conventional technique. As shown in the images with reference numerals g661 and g662, with the conventional technique, the target object sways violently from side to side and up and down, making it impossible to hold and causing it to fall. The images with reference numerals g671 and g672 are examples of the state when control is performed by dynamically adjusting the gain using the second technique. On the other hand, as shown in the images with reference numerals g671 and g672, even with only the second technique of this embodiment, the target object sways less and can be held without falling.

[0126] 15 to 18, an example in which the object is gripped with two fingers has been described, but the number of fingers used for gripping may be three or more. Furthermore, the method of the second embodiment and the method of the third embodiment described above may be used alone or together.

[0127] [Example of Processing Procedure] Next, an example of the processing procedure of the control system 1 in each of the second and third embodiments will be described. Fig. 19 is a flowchart of the processing of the control system according to the second embodiment.

[0128] (Step S11 ) The acquisition unit 31 acquires a detection value from the sensor 23 of the hand 2 .

[0129] (Step S12) The contact force calculation unit 32 extracts a contact point using the acquired detection value, and determines the position of the extracted contact point.

[0130] (Step S13) The contact force calculation unit 32 calculates the contact force at the obtained contact point, including an external force term.

[0131] (Step S14) The contact force calculation unit 32 offsets the force instruction using the above-mentioned equations (14) and (15).

[0132] (Step S15) The control value generating unit 33 generates a control value for controlling the hand 2 using the offset force instruction.

[0133] (Step S16 ) The output unit 35 outputs the generated control value to the hand 2 .

[0134] FIG. 20 is a flowchart of the process of the control system according to the third embodiment.

[0135] (Step S21) The acquisition unit 31 acquires a detection value from the sensor 23 of the hand 2.

[0136] (Step S22) The contact force calculation unit 32 extracts a contact point using the acquired detection value, and determines the position of the extracted contact point.

[0137] (Step S23) The contact force calculation unit 32 calculates the contact force at the obtained contact point, including an external force term.

[0138] (Step S24) The contact force calculation unit 32 increases or decreases the gain using the above-mentioned equation (16).

[0139] (Step S25) The control value generating unit 33 generates a control value for controlling the hand 2 using the increased or decreased gain.

[0140] (Step S26) The output unit 35 outputs the generated control value to the hand 2.

[0141] As described above, in each embodiment, the external force term E ａｄｄ The slip information is included in the external force term E ａｄｄ is made integrable (the system is a conservative system). As a result, in this embodiment, the shape of the potential function is implicitly known and Lyapunov stability is achieved.

[0142] As a result, according to each embodiment, slip suppression and stabilization can be achieved simply and easily by using the detection values ​​of a sensor that can indirectly or directly measure the time derivative of force, without identifying or estimating physical parameters.

[0143] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings used in the following description, the scale of each component has been appropriately changed so that each component can be recognized. In all drawings used to explain the embodiments, components having the same function are designated by the same reference numerals, and repeated explanations will be omitted. In addition, "based on XX" in this application means "based on at least XX" and includes cases where the component is based on other elements in addition to XX. Furthermore, "based on XX" is not limited to cases where XX is used directly, but also includes cases where the component is based on XX after calculation or processing. "XX" is any element (for example, any information).

[0144] [Overview] First, the terms "point contact," "rolling contact," and "sliding contact" used in this embodiment will be explained. FIG. 21 is a diagram for explaining point contact and rolling contact where no sliding occurs. The diagrams indicated by symbols g1011 and g1012 are diagrams of examples of point contact states. The diagram indicated by symbol g1012 is an enlarged view of the gripping state indicated by symbol g1011. The arrow g1013 shows an image of the force acting from the fingertip on the target object and its direction. The diagram indicated by symbol g1021 is a diagram showing an example of a rolling contact state. The arrow g1022 shows an image of the fingertip rolling on the target object.

[0145] Conventional control methods stabilize the dynamics of a target object based on its estimated CoM (weight). Grasping control requires accurate joint forces that are non-slip, but this is difficult. The prerequisite for control of point and rolling contact is that point contact is equal to rolling contact, and the posture of the grasped object is estimated and controlled solely based on contact information between the fingertip's contact point and the target object's contact point.

[0146] FIG. 22 is an image diagram of the contact points between the target object obj and the fingers fin (fin1001 to fin1003) of the hand in sliding contact, forces f1001 to f1003 acting from the fingertips to the target object obj, and forces f1005 to f1006 acting on the target object obj. Note that while FIG. 22 shows an example with three fingers, the number of fingers can be two or more. The prerequisite for control that also uses sliding contact is that point contact ∈ rolling contact ∈ sliding contact, and contact information alone is insufficient to estimate the posture of the target object, making stable grasp control difficult.

[0147] In the following examples, the hand may be remotely controlled by an operator wearing a head-mounted display, data gloves, etc. However, the motion control is not limited to remote control, and the operator may visually check the hand and target object, or the hand may be automatically controlled.

[0148] FIG. 23 is a diagram showing models and constraint conditions for each contact state. The diagram indicated by reference numeral g1031 is an image diagram of the contact point between the target object obj and the finger fin of the hand 1002, the force acting from the fingertip to the target object obj, and the force acting on the target object obj. The diagram indicated by reference numeral g1032 is an example model of the finger fin and the target object obj when controlled in point contact. The constraint conditions in this case are no rolling and no slipping. Conventional control methods could only handle two or more points of contact. The diagram indicated by reference numeral g1033 is an example model of the finger fin and the target object obj when controlled in rolling contact. The constraint conditions in this case are rolling but no slipping. This was also possible with conventional control methods. The diagram indicated by reference numeral g1034 is an example model of the finger fin and the target object obj when controlled in slipping contact. In this case, the constraint conditions include both rolling and sliding, which could not be handled with conventional control methods.

[0149] In this embodiment, the gripping unit is controlled without using images captured by the imaging device.

[0150] The control method of this embodiment will be described. First, the problems of the conventional method will be described. FIG. 24 is a model for explaining the problems of the conventional method. FIG. 25 is a diagram showing the relationship between position and energy, which explains the problems of the conventional method. In FIG. 25, the horizontal axis is position and the vertical axis is energy. In the conventional method, all the energy E generated by the finger ａｌｌ is expressed as the dissipative energy E ｄｉｓｓｐａｔｕｖｅ and the conserved energy E ｃｏｓｅｒｖｅｄ It is expressed in terms of

[0151]

[0152] Conserved energy E ｃｏｓｅｒｖｅｄ The term is expressed as the kinetic energy E ｋｉｎｅｔｉｃ and the potential energy E ｐｏｔｅｎｔｉａｌ It is expressed in terms of

[0153]

[0154] In the conventional method, the conserved energy E ｐｏｔｅｎｔｉａｌ The problem is that it is a function dependent on the position and orientation, as shown in Figure 25, and it can only control point contact and rolling contact, but cannot control sliding contact.

[0155] In contrast, in this embodiment, the stored energy E ｐｏｔｅｎｔｉａｌ The gravitational energy E ｇｒａｃｉｔｙ and external force Ｅａｄｄ By expressing it in terms of

[0156]

[0157] In this way, in this embodiment, the external force E ａｄｄ The term includes slip information, making the system integrable, i.e., conservative. The external force E that satisfies this condition ａｄｄ An example of the formula is the following formula (20). This allows the shape of the potential function to be implicitly known, and Lyapunov stability can be achieved. In this embodiment, formula (20) is expressed as "f ｔｉｐ " and "f" and simplified to "p ・ ｔｉｐ " to "p ・" and simplified it to E ａｄｄ = ∫(f p ・ ) dt.

[0158]

[0159] Equation (20) is a time integral. The time integral value of the force often contains slip information. In the embodiment, f ｔｉｐ is the force of the fingertip at the contact point, and p ｔｉｐ is the position of the contact point (the position of the fingertip). ・ With f ・ ｔｉｐ is the change in fingertip force, and p ・ ｔｉｐ is the change in position of the contact point.

[0160] The stability condition is the external force term E ａｄｄ The slip information is included in the external force term E ａｄｄ is integrable (the system is a conservative system), and in this case, the force differential value, which is the time change value of the force, is required. ａｄｄ The slip information is included in the external force term E ａｄｄ To satisfy the condition that p is integrable (the system is a conservative system), ・ ｔｉｐ is, for example, the following equation (21).

[0161]

[0162] Equation (21) is ａｄｄ = ∫(f p ・ ) dt, equation (20) can also be expressed as the following equation (22).

[0163]

[0164] Furthermore, the stability of an autonomous system can be divided into Lyapunov stability and near-near stability. For any s, if δ exists and if ||x(0)|| < δ, then if ||x(t)|| < ε, then the equilibrium point x = 0 is Lyapunov stable. In other words, when a trajectory that starts from near an equilibrium point of a dynamical system continues to remain near the equilibrium point, the equilibrium point is said to be Lyapunov stable.

[0165] [Acquisition of Force Differential Values] The following methods can be considered for directly acquiring the force differential values ​​described above. (Example 1) Using an event camera When using an event camera, it is possible to acquire only the changing parts in the image, but it is difficult to directly acquire the force differential values. (Example 2) Using a software event-driven sensor value acquisition circuit This method is intended to reduce the amount of data transferred; for example, it only detects when the tactile sensor makes contact, stores the previous value, and performs calculations in software, resulting in low responsiveness and a high load on the calculation device. (Example 3) Using a hardware event-driven sensor value acquisition circuit This method is an improvement over (Example 2), and performs calculations using an analog circuit. However, it is necessary to store the previous value, and a memory circuit is also added. Furthermore, it takes time to read the previous value. With the above methods, it is difficult to implement a high-response, compact system.

[0166] For this reason, in this embodiment, a force differential value is generated using the time change output circuit 1032. Then, in this embodiment, the force differential value generated by the time change output circuit 1032 is used to perform control when slippage occurs.

[0167] 26 is a diagram showing an example of a time change output circuit according to this embodiment. As shown in Fig. 26, the time change output circuit 1032 includes, for example, an inductance L and a differential amplifier circuit 1321. The time change output circuit 1032 acquires a detection value from a sensor 1023 included in the hand 1002.

[0168] One end of the sensor 1023 is connected to the power supply voltage VDD. One end of the inductance L is connected to the other end of the sensor 1023 and the positive input terminal V of the differential amplifier circuit 1321. ＋ , and the other end is connected to the negative input terminal V of the differential amplifier circuit 1321. － and is grounded (GND). The differential amplifier circuit 1321 has a positive input terminal V ＋ and the value input to the negative input terminal V －The output Vout obtained by multiplying the difference between the current change value input to the differential amplifier circuit 1321 and the gain α of the differential amplifier circuit 1321 is output to the control unit 1033. The output of the differential amplifier circuit 1321 is a force differential value. In other words, the differential amplifier circuit 1321 receives a value (for example, V ＋ ), and the value of the sensor 1023 is the current change value (for example, V － ) are input. The differential amplifier circuit 1321 then outputs the time change value of the contact force with the target object.

[0169] The sensor 1023 is, for example, a pressure-sensitive resistive tactile sensor whose resistance changes in response to the applied force, such as a load cell, which is a sensor that detects force (mass, torque), and has a variable resistance value r. The detected value is expressed as F = f(r). The pressure-sensitive resistive tactile sensor may also be a thin-film pressure-sensitive sensor.

[0170] The inductance L detects the current change (di / dt). The differential amplifier circuit 1321 detects the change in the current flowing across the inductance L, V ＋ (-V － ) = -L(di / dt) is input. If the gain of the differential amplifier circuit 1321 is α, the output Vout of the differential amplifier circuit 1321 is given by the following equation (23). This output is df / dt, i.e., the force differential value. The value of inductance L and gain α are determined by experiment or simulation depending on, for example, the characteristics of the sensor, the target object, the work content, etc.

[0171]

[0172] As a result, in this embodiment, the time change value of the force can be directly measured and generated by an analog circuit using the inductance L of the time change output circuit 1032. Furthermore, according to this embodiment, since the circuit configuration is an analog circuit, responsiveness is high. Furthermore, the circuit configuration of this embodiment does not require a circuit for saving or reading the previous force value as in the example described above, and can be made smaller.

[0173] [Example of a System Including a Time-Varying Output Circuit] Next, an example of a system including a time-varying output circuit will be described. FIG. 27 is a diagram showing an example of the configuration of a control system including a force differential value acquisition circuit. As shown in FIG. 27 , the control system 1001 includes, for example, a hand 1002 and a control device 1003. The hand 1002 includes, for example, a plurality of fingers 1021 (1021-1, ..., 1021-n) (n is an integer of two or more) (movable parts), a plurality of actuators 1022 (1022-1, ..., 1022-n), a plurality of sensors 1023 (1023-1, ..., 1023-n), and a base 1024. The control device 1003 includes, for example, an acquisition unit 1031, a time-varying output circuit 1032, a control unit 1033, a drive circuit 1034, an output unit 1035, and a memory unit 1036.

[0174] The hand 1002 is, for example, an end effector or a gripper. The hand 1002 has at least two fingers 1021. Alternatively, each hand 1002 may have at least one finger. The hand 1002, for example, grasps a target object under the control of the control device 1003. The hand 1002 may be one arm or both arms, and may have an arm and a body. The hand 1002 may also be included in, for example, a robot having a body. The hand 1002 and the control device 1003 are connected to each other via a wired or wireless network NW.

[0175] The fingers 1021 (1021-1, ..., 1021-n) are provided with joints.

[0176] The actuators 1022 (1022-1, ..., 1022-n) are attached to the joints of the finger portion 1021 and the joints between the finger portion 1021 and the base portion 1024. The actuators 1022 may include a drive circuit 1034.

[0177] The sensors 1023 (1023-1, ..., 1023-n) are, for example, finger pressure sensors attached to the pads of the fingers 1021 or six-axis sensors attached indirectly. The six-axis sensor detects forces along three axes (x, y, z) and moments along three axes (α, β, γ).

[0178] The base 1024 is the part to which the fingers 1021 are attached.

[0179] The control device 1003 uses information acquired from the hand 1002 to control the hand 1002 and a contact object (for example, a grasped object or a floor surface) that comes into contact with the finger portion 1021 of the hand 1002 .

[0180] The acquisition unit 1031 acquires the detection information detected by the sensor 1023 of the hand 1002 .

[0181] The time change output circuit 1032 receives the detection value of the sensor 1023 acquired by the acquisition unit 1031 as an input and outputs a force differential output to the control unit 1033. Note that the time change output circuit 1032 may be provided for each sensor 1023, for example, or the detection value of the sensor 1023 may be temporarily stored in the storage unit 1036 and processed in a time-division manner.

[0182] The control unit 1033 generates a control value for controlling the hand 1002 using the force differential output output by the time change output circuit 1032 .

[0183] The drive circuit 1034 outputs a drive signal for driving the corresponding actuator 1022 to the output unit 1035 in accordance with the control value generated by the control unit 1033. The drive circuit 1034 may be provided in the hand 1002.

[0184] When the control device 1003 includes a drive circuit 1034, the output unit 1035 outputs the control value generated by the control unit 1033 to the hand 1002. When the hand 1002 includes a drive circuit 1034, the output unit 1035 outputs the drive signal generated by the drive circuit 1034 to the hand 1002.

[0185] The storage unit 1036 stores programs, thresholds, mathematical expressions, identification information for identifying the hand 1002, and the like required for control.

[0186] 27 is merely an example and is not limiting. Other components may be included. For example, the hand 1002 and the control device 1003 are each equipped with a power supply unit.

[0187] [Example of Sensor Output and Example of Force Derivative Value] Next, an example of the output and example of the force derivative value of the sensor 1023 will be described. Fig. 28 is a diagram showing an example of the sensor output. The horizontal axis represents the force applied to the sensor 1023, and the vertical axis represents the resistance value. Symbol g1051 represents a first force applied to the sensor 1023, and symbol g1052 represents a second force applied to the sensor 1023 that is greater than the first force. As shown in Fig. 28, the smaller the force applied to the sensor 1023, the larger the resistance value, and vice versa.

[0188] 29 is a diagram showing an example of changes in force applied to a sensor, force derivative, and output of a differential amplifier circuit. Graph g1060 is an example of changes in force over time. In graph g1060, the horizontal axis represents time and the vertical axis represents force. Graph g1070 is an example of changes in force derivative di / dt over time. In graph g1070, the horizontal axis represents time and the vertical axis represents force derivative di / dt. Graph g1080 is an example of changes in output Vout of the differential amplifier circuit over time. In graph g1070, the horizontal axis represents time and the vertical axis represents output Vout of the differential amplifier circuit.

[0189] As shown in the graph with reference numeral g1060, the period from time t1 to t2 is, for example, a period during which a first force is applied. The period from time t2 onward is, for example, a period during which a second force is applied. This change in force is detected by the time change output circuit 1032, and as shown in the graphs with reference numerals g1070 and g1080, the force differential value and the output of the differential amplifier circuit increase in accordance with the applied force at times t1 and t2 when the force changed. Note that the examples of output and change shown in FIGS. 28 and 29 are merely examples and are not limiting.

[0190] [Example of a Grasping Operation Using a Conventional Method and an Example of a Grasping Operation Using the Present Embodiment] Next, an example of a grasping operation using point contact and rolling contact using a conventional method and an example of a grasping operation using point contact, rolling contact, and sliding contact using the present embodiment will be described. FIG. 30 is a side view of a hand during grasping. The example in FIG. 30 is an image diagram showing a hand 1002 attempting to stably grasp a target object obj with two fingers 1021 (1021-1, 1021-2). The target object obj is an object whose top diameter is shorter than its bottom diameter, such as a cup placed with its mouth facing downward. Circles 1025 (1025-1-1, 1025-1-2, 1025-2-1, 1025-2-2) represent joints. Points g1101 and g1102 represent contact points between the fingers 1021 and the target object obj. A line g1103 indicates a tangent direction to the target object obj, a line g1104 indicates a normal direction to the target object obj, and a dashed arrow g1105 indicates a force generated from the contact points (points g1101 and g1102) on the finger portion 1021. Note that the direction of the arrows may be reversed.

[0191] The methods for confirming the grasping operation using point contact and rolling contact in the conventional method and the grasping operation using point contact, rolling contact, and sliding contact in this embodiment are as follows: (A) A static grasp is performed while a specific internal force (5 N) is applied. (B) An input (disturbance) that exceeds the static friction region is applied. The criteria for determining whether the grasp is successful or unsuccessful are as follows: (Success) After exceeding the static friction region, the object returns to the static friction region. (Failure) After exceeding the static friction region, the object never returns to the static friction region.

[0192] Note that the conventional grip control method uses, for example, compliance control. For this reason, a rolling constraint is set as a prerequisite, and control is performed at the contact point on the manipulated object side. In the following explanation, the subscript cmd indicates the target value of control (target value of angle and position) sent to the actuator. The target value of force in the conventional method, f ｃｍｄ is expressed by the following equation (24). ｒｅｆ and p ａｃｔ Each of these is a fixed value. ｐ is the gain, and p ｒｅf is the target value of the finger position, the position of the contact point, and p ａｃｔ is the position of the contact point between the fingertip and the target object. The stability is Lyapunov stable, and the target energy E ｃｍｄ is expressed by the following equation (25).

[0193]

[0194]

[0195] FIG. 31 shows an example of a grasping operation using point contact and rolling contact according to a conventional method. Note that FIG. 31 is a simulation result. Reference symbol g1201 indicates the start of grasping, reference symbol g1202 indicates the state in which force is applied, and reference symbol g1203 indicates the state in which the target object obj has slipped off the finger 1021. Reference symbol 1211 indicates the force and each axis generated in each finger 1021 indicated by reference symbol 1201. Reference symbol 1212 indicates the force and each axis generated in each finger 1021 indicated by reference symbol 1202. Reference symbol 1213 indicates the force and each axis generated in each finger 1021 indicated by reference symbol 1203. Note that in reference symbols g1201 to g1203 and g1211 to g1213, each line indicates the axial direction, the force acting from the fingertip to the target object, etc. In the conventional grasping operation using point contact and rolling contact, the target object obj slips off the finger 1021 as shown by the symbol g1203 and cannot be maintained by the finger 1021.

[0196] Figure 32 shows the change in the direction of force over time and the change in velocity at the contact point over time in a gripping operation using point contact and rolling contact according to a conventional method. Note that Figure 32 is a simulation result. The horizontal axis of reference symbol g1230 is time (sec), and the vertical axis is the angle θ of the force generated at the contact point. The angle θ is the angle between the normal direction of the target object obj and the perpendicular line, as shown in Figure 30. The horizontal axis of reference symbol g1240 is time (sec), and the vertical axis is the velocity (m / s) generated at the contact point.

[0197] Reference symbol g1220 indicates the state of the finger portion 1021. Reference symbol g1221 indicates the start of grasping, reference symbol g1222 indicates the state in which force is applied, and reference symbol g1223 indicates the state in which the target object obj has slipped off the finger portion 1021.

[0198] Reference symbol g1230 indicates the change in the direction of force over time. Region g1231 indicates a zone where slippage occurs but the frictional force is not exceeded and gripping is maintained (static friction region), region g1232 indicates a zone where the frictional force exceeds the gripping force, and region g1233 indicates an error zone. The angle θ indicated by arrow g1234 indicates that gripping is maintained in the gripping state indicated by reference symbol g1221. The angle θ indicated by arrow 1235 indicates that the frictional force has been exceeded and the angle is changing rapidly. The angle θ indicated by arrow 1236 indicates that the target object obj has slipped off the finger 1021 and fallen, preventing the target object obj from returning to the finger 1021.

[0199] Reference symbol g1240 represents the change in velocity at the contact point over time. Between 0.8 and 1.0 seconds, as shown by reference symbol g1230, the angle of the force changes suddenly, indicating that slippage is occurring.

[0200] As described above, with the control of the conventional method, the robot did not return to the static friction region after going beyond it, so it was unable to maintain grip (failure) and was unable to achieve stable grip beyond the static friction region. Note that with the control of the conventional method, the stable region (maximum target internal force - minimum target internal force) was approximately 0.2 (N).

[0201] FIG. 33 shows an example of the change in force direction over time, and the change in force and force derivative over time during control using a conventional method. The horizontal axis represents time (msec), and the vertical axis represents force and force derivative. The graph indicated by reference symbol g1250 shows the change in force (N) over time. The graph indicated by reference symbol g1260 shows the change in force derivative (N) over time. A negative force derivative, as shown by the dashed circle g1261, indicates a state of slippage, as seen in the period from 0.8 to 1.0 indicated by reference symbol g1240 in FIG. 32. Furthermore, during the error region g1241 of graph g1240 in FIG. 28, the force derivative changes, but because control using the force derivative is not performed, slippage continues and the fingertip velocity fluctuates.

[0202] FIG. 34 shows an example of a grasping operation using point contact, rolling contact, and sliding contact according to this embodiment. Note that FIG. 34 is a simulation result. Reference symbol g1301 indicates the start of grasping, reference symbol g1302 indicates a state in which force is applied, and reference symbol g1303 indicates a state in which the finger 1021 maintains a grasp of the target object obj. Reference symbol 1311 indicates the force and each axis generated in each finger 1021 indicated by reference symbol 1301. Reference symbol 1312 indicates the force and each axis generated in each finger 1021 indicated by reference symbol 1302. Reference symbol 1313 indicates the force and each axis generated in each finger 1021 indicated by reference symbol 1303. Note that in reference symbols g1301 to g1303 and g1311 to g1313, each line indicates an axial direction, a force acting from the fingertip to the target object, etc. In the gripping operation using point contact, rolling contact, and sliding contact in this embodiment, the finger 1021 can maintain a grip on the target object obj, as indicated by the reference symbol g1303.

[0203] Figure 35 shows the change in the direction of force over time and the change in velocity at the contact point over time in a gripping operation using point contact, rolling contact, and sliding contact in this embodiment. Note that Figure 35 is a simulation result. The horizontal axis of symbol g1330 is time (sec), and the vertical axis is the angle θ of the force generated at the contact point. The horizontal axis of symbol g1340 is time (sec), and the vertical axis is the velocity (m / s) generated at the contact point.

[0204] Reference symbol g1320 indicates the state of the finger portion 1021. Reference symbol g1321 indicates the start of grasping, reference symbol g1322 indicates the state in which force is being applied, and reference symbol g1323 indicates the state in which the target object obj does not slip off the finger portion 1021 and can be maintained in a grasp.

[0205] Reference symbol g1330 indicates the change in the direction of the force with respect to time. Region g1331 is a zone (static friction region) where slippage occurs but the frictional force is not exceeded and gripping is maintained, and region g1332 is a zone where the frictional force exceeds the gripping force. The angle θ indicated by arrow g1334 indicates that gripping is maintained in the gripping state indicated by reference symbol g1321. The angle θ indicated by arrow 1335 indicates that the frictional force has been exceeded and the angle is changing rapidly. The angle θ indicated by arrow 1336 indicates that the target object obj does not slip off the finger 1021, but has returned to the static friction region and has returned to the finger 1021.

[0206] Symbol g1340 represents the change in velocity at the contact point with respect to time. Between 0.4 and 0.6 seconds, as shown by symbols g1330 and g1340, the angle of the force changes suddenly, indicating that slippage is occurring.

[0207] In this way, with the control of this embodiment, after going beyond the static friction region, the robot returned to the static friction region, maintaining the grip (success), and achieving stable grip beyond the static friction region. Note that with the control of this embodiment, the stable region (maximum target internal force - minimum target internal force) was approximately 4.0 (N), which was approximately 20 times larger than the control of the conventional method.

[0208] FIG. 36 shows an example of the change in the direction of force over time, and the change in force and force derivative over time during control using the method of this embodiment. The horizontal axis represents time (msec), and the vertical axis represents force and force derivative. The graph with reference symbol g1350 shows the change in force (N) over time. The graph with reference symbol g1360 shows the change in force derivative over time. The force derivative in the area surrounded by the dashed circle g1261 is negative, but while in the conventional technology this drops to around -6, this negative value can be quickly detected at around -3.5 in this embodiment.

[0209] As a result, according to this embodiment, changes in the force differential value are detected, as in the period from 0.4 to 0.6 (msec) in the graph of reference symbol g1340 in Fig. 35, and energy control is performed using the detected changes in the force differential value, so that the target object can be continuously grasped without slipping off. Furthermore, according to this embodiment, there is no fluttering of the fingertip speed, as occurs with conventional control methods.

[0210] (Modification) FIG. 37 shows an example of control using conventional technology and control using a modification of this embodiment in which the force command is offset and the gain is increased or decreased. The target object obj is, for example, an irregularly shaped object, such as a small rock. The graph indicated by reference symbol g1520 shows the relationship between the command force and the Lyapunov function. The range indicated by reference symbol g1521 is the static friction region (friction occurring in a stationary object). The range indicated by reference symbol g1522 is the dynamic friction region (friction occurring in a moving object). Reference symbol g1523 is the sliding boundary. The dashed line g1524 shows the relationship between the command force and the Lyapunov function in the static friction region. Lines g1525 and g1526 show the relationship between the command force and the Lyapunov function in the dynamic friction region.

[0211] In this prior art, for example, compliance control, as shown by symbol g1520, the object is pulled into the minimum point g1527 of the boundary line g1523 between the static friction region and the dynamic friction region and stabilizes. That is, the object moves in a slight slipping direction as shown by line g1524, but stabilizes at boundary line g1523 and cannot return. The problem with this prior art is that the object motion is stable due to stabilization at the slip boundary line g1523, but the object motion is violent due to excessive control input.

[0212] In the prior art, slippage information f ・ ａｃｔ Calculate the force command from the energy expression including ・ ｃｍｄ is expressed in a non-slip form as in the following equation (26).

[0213]

[0214] Then, the target force instruction f ｃｍｄ is expressed as in the following equation (27): In equation (27), PI represents PI (Proportional-Integral) control.

[0215]

[0216] In contrast to this, in the modified example, in order to extract the change during slippage, the control unit 1033A offsets the force command as shown in the following equations (28) and (29). In this way, in this embodiment, since the error component is subtracted, only the change during slippage can be extracted and controlled.

[0217]

[0218]

[0219] The offset is the target value of the change in energy E ・ ｃｍｄ f in equation (26) ａｃｔ and f ・ ａｃｔ From equation (29), f ｅｒｒｏｒ and f ・ ｅｒｒｏｒ and replace with f ｅｒｒｏｒ f as in equation (28). ｃｍｄ and f ａｃｔ In the control of the conventional technique using equation (26), ａｃｔ On the other hand, in the control of the present embodiment using the formula (29), the curve converges to the minimum value g1527 as shown in the formula (28). ｃｍｄ From f ａｃｔ By subtracting (offsetting) the line g1574 can be controlled so that it does not converge at the boundary line like lines g1574 and g1575 in the graph of symbol g1570, but rather line g1574 becomes the bottom.

[0220] Furthermore, in the modified example, in order to make the change gentler, the control unit 1033A uses a command E ・ ｃｍｄ From the change in the gain k ｆ is updated by increasing or decreasing k ｅ is the gain and is a fixed value.

[0221]

[0222] The graph of reference symbol g1570 shows the relationship between the command force and the Lyapunov function. The range of reference symbol g1571 is the static friction region. The range of reference symbol g1573 is the dynamic friction region. Reference symbol g1573 is the sliding boundary. The dashed line g1574 shows the relationship between the command force and the Lyapunov function in the static friction region. The line g1575 shows the relationship between the command force and the Lyapunov function in the dynamic friction region.

[0223] In the control of the modified example, when the boundary between the static friction region and the dynamic friction region is crossed, the change is controlled gradually as indicated by arrow g1576, allowing for continued grip as indicated by reference symbol g1554. As a result, even at the boundary line, the change is gradual as indicated by arrow g1576 in the graph indicated by reference symbol g1570, rather than a minimum value represented by a steeply inclined line as indicated by reference symbol g1520. In this modified example, control is performed to remain within the static friction region where a stable grip can be maintained. This modified example solves the problems of the prior art through such control. In this modified example, force (f) is also required in addition to the force differential value. For this reason, in this modified example, force (f) is also detected by a time-varying output circuit.

[0224] 38 is a diagram showing a modified example of the time change output circuit of this embodiment. The time change output circuit 1032A includes, for example, an inductance L, a differential amplifier circuit 1321, a buffer circuit 1322, and a resistor R. The time change output circuit 1032A acquires a detection value from the sensor 1023 provided in the hand 1002.

[0225] One end of the sensor 1023 is connected to the power supply voltage VDD. One end of the inductance L is connected to the other end of the sensor 1023 and the positive input terminal V of the differential amplifier circuit 1321. ＋ , and the other end is connected to the negative input terminal V of the differential amplifier circuit 1321. － , connected to a first input terminal of a buffer circuit 1322, and connected to one end of a resistor R. The other end of the resistor R is grounded (GND).

[0226] The second input terminal of the buffer circuit 1322 is connected to the output terminal, and the output terminal is connected to the control unit 1033A. The buffer circuit 1322 divides the current change di / dt into a voltage and inputs it as a voltage. The output V'out of the buffer circuit 1322 is a force f (contact force with the target object). The buffer circuit 1322 is, for example, a voltage follower circuit, and is configured such that the current change di / dt is converted into a voltage and input to the positive input terminal, and the negative input terminal and output terminal are connected. The buffer circuit 1322 may have an oscillation-preventing resistor or capacitor connected to its output terminal, for example.

[0227] The differential amplifier circuit 1321 receives a change in the current flowing across the inductance L, and outputs an output Vout, which is a force differential value, to the control unit 1033 A. The value of the inductance L and the gain α of the differential amplifier circuit 1321 are determined by experiment or simulation depending on, for example, the characteristics of the sensor, the target object, the work content, etc.

[0228] According to this circuit configuration, in addition to the force differential output Vout=-αLdi / dt of the circuit configuration in Fig. 26, the force f can also be output to the control unit 1033A. The control unit 1033A may use this force f to offset the force command or increase or decrease the gain. Note that the control unit 1033A may perform both the offset of the force command and the increase or decrease of the gain, or may perform only one of them.

[0229] As a result, in this modified example, the time change value of the force can be directly measured and generated by an analog circuit using the inductance L of the time change output circuit 1032. And, according to this modified example, since the circuit configuration is an analog circuit, the response is high. Furthermore, with the modified circuit configuration, there is no need for a circuit that stores or reads the previous value of the force as in the example described above, and therefore the device can be made smaller.

[0230] [Processing Procedure] Next, an example of the processing procedure of the control system 1001 using the force differential value of this embodiment will be described. Fig. 39 is a flowchart of the processing of the control system according to this embodiment. Note that the processing procedure using Fig. 39 will explain the processing in the case of the circuit configuration of Fig. 26. In the case of the circuit configuration of Fig. 38, for example, the force is also detected in step S1003, and the force command is offset and the gain is increased or decreased in step S1004.

[0231] (Step S1001 ) The acquisition unit 1031 acquires a detection value from the sensor 1023 of the hand 1002 .

[0232] (Step S1002) The time variation output circuit 1032 extracts a contact point using the acquired detection value, and determines the position of the extracted contact point.

[0233] (Step S1003) The time change output circuit 1032 receives the detection value acquired by the acquisition unit 1031 as an input and generates a force differential value, which is a time change value of the force.

[0234] (Step S1004 ) The control unit 1033 generates a control value for controlling the hand 1002 using the force differential value output by the time change output circuit 1032 .

[0235] (Step S1005) The output unit 1035 outputs the generated control value to the hand 1002. As a result, the control device 1003 applies force to the contact surface with the multiple fingers 1021 (movable part), thereby controlling the movable part or the contact object.

[0236] In the above-described embodiments, examples have been described in which a robot hand or the like grasps a target object without slipping, but the present invention is not limited to this. The control method of each of the above-described embodiments can be applied to machines and devices that are intended to suppress slippage, such as saddle-type vehicles, motorcycles, three-wheeled vehicles, four-wheeled vehicles, automatic lawnmowers, tillers, snowplows, and devices that assist human movement, in addition to robot hands or the like.

[0237] In addition, a program for implementing all or part of the functions of the control device 3, 1003 of the present invention may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be loaded into a computer system and executed to perform all or part of the processing performed by the control device 3, 1003. Note that the term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer system" also includes a WWW system equipped with a homepage provision environment (or display environment). The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, the term "computer-readable recording medium" also includes devices that retain a program for a certain period of time, such as volatile memory (RAM) within a computer system that acts as a server or client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line. Alternatively, some or all of these components may be realized by LSI (Large Scale Integration) hardware (including circuitry) such as an ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit), or SOC (System On Chip), or may be realized by a combination of software and hardware.

[0238] The program may also be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by transmission waves in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may also be a program that realizes part of the above-mentioned functions. Furthermore, the program may be a so-called differential file (differential program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0239] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention.

[0240] 1...control system, 2...hand, 3...control device, 21, 21-1, ..., 21-n...finger portion, 22, 22-1, ..., 22-n...actuator, 23, 23-1, ..., 23-n...sensor, 24...base portion, 31...acquisition portion, 32...contact force calculation portion, 33...control value generation portion, 34...drive circuit, 35...output portion, 36...storage portion 1001...control system, 1002...hand, 1003...control device, 1021, 1021-1, ..., 1021-n...finger portion, 1022, 1022-1, ..., 1022-n...actuator, 1023, 1023-1, ..., 1023-n...sensor, 1024...base portion, 1031...acquisition portion, 1032, 1032A...time change output circuit, 1033, 1033A...control portion, 1034...drive circuit, 1035...output portion, 1036...storage portion

Claims

1. A method for controlling at least one movable part and a contacting object in contact with the movable part, wherein a control device controls the movable part or the contacting object by applying force to the contact surface using multiple movable parts, and when calculating the contact force generated on the contact surface based on energy, the total energy of the entire movable part or the contacting object is considered to be the sum of stored energy and damping energy and does not increase, and an external force term in the stored energy term includes information on slippage between the movable part and the contacting object relative to the contact surface, and is calculated so that the external force term is integrable.

2. A control method for manipulating a contact object using a hand with multiple finger parts, wherein the finger parts are movable parts, and a control device controls the position and posture of the contact object by applying force using the multiple finger parts, and when calculating the contact force generated on the contact surface between the finger parts and the contact object based on energy, the energy of the entire movable part is considered to be the sum of stored energy and damping energy and does not increase, and an external force term in the stored energy term includes information on slippage on the contact surface between the finger parts and the contact object, and is calculated so that the external force term is integrable.

3. The external force term is the sum of the time-differentiated contact forces of the respective movable parts against the contact object, and is expressed by the following equation: f is the force at the contact point, and p ・ The movable body control method according to claim 1 or 2, wherein ∑ is a change in the position of the contact point.

4. The command value of the time derivative of the energy of the moving part is expressed by the following equation: k ｆ The movable body control method according to claim 1 or 2, wherein: ∑f is a gain; and f is a force at the contact point.

5. The control device issues a force command E to the movable part. ・ ｃｍｄ By offsetting using the following equation, the change in slip is extracted and controlled. f ｃｍｄ is the target force value, and f ａｃｔ The movable object control method according to claim 1 or 2, wherein: is slippage information.

6. The control device uses the following equation to calculate a force command E to the moving part that is correlated with a Lyapunov function: ・ ｃｍｄ The gain is increased or decreased based on the change in k ｆ , k ｅ The movable body control method according to claim 1 or 2, wherein each of the parameters is a gain.

7. A control device for a movable body that controls at least one movable part and a contacting object in contact with the movable part or the movable part itself, comprising: a control command generation unit that controls the movable part or the contacting object by applying force to a contact surface using a plurality of the movable parts; and a contact force calculation unit that, when calculating the contact force generated on the contact surface based on energy, calculates the contact force by assuming that the total energy of the entire movable part or the contacting object is the sum of stored energy and damped energy and does not increase, wherein the contact force calculation unit calculates the external force term in the stored energy term so that it includes information on slippage between the movable part and the contacting object relative to the contact surface and is integrable.

8. A control device for a movable body that operates a contact object with a hand having a plurality of finger units, comprising: a control command generation unit that controls the position and posture of the contact object by applying force from the plurality of finger units; a contact force calculation unit that, when calculating the contact force generated on the contact surface between the finger units and the contact object based on energy, calculates the contact force by assuming that the energy of the entire movable unit is the sum of stored energy and damping energy and does not increase; and the contact force calculation unit calculates an external force term in the stored energy term that includes information on slippage on the contact surface between the finger units and the contact object, and the external force term is integrable.

9. A time change output circuit comprising a differential amplifier circuit that receives a value obtained by a sensor that acquires contact force with a target object and a current change value due to inductance in the sensor value, and outputs a time change value of the contact force with the target object.

10. A time variation output circuit according to claim 9, wherein one end of the sensor is connected to a power supply voltage, one end of the inductance is connected to the other end of the sensor and the positive input terminal of the differential amplifier circuit, and the other end is connected to the negative input terminal of the differential amplifier circuit and is also grounded, and the differential amplifier circuit outputs a time variation value of force obtained by multiplying the difference between the value input to the positive input terminal and the current variation value input to the negative input terminal by the gain of the differential amplifier circuit.

11. The time-varying output circuit according to claim 9, further comprising a resistor and a buffer circuit, wherein an input of a current change value due to the inductance of the sensor value is grounded via the resistor and connected to an input of the buffer circuit, and the buffer circuit outputs the contact force with the target object.

12. The time-varying output circuit according to claim 11, wherein one end of the sensor is connected to a power supply voltage; one end of the inductance is connected to the other end of the sensor and the positive input terminal of the differential amplifier circuit, and the other end is connected to the negative input terminal of the differential amplifier circuit, one end of the resistor, and a first input terminal of the buffer circuit; the other end of the resistor is grounded; the differential amplifier circuit outputs a time-varying value of force obtained by multiplying the difference between the value input to the positive input terminal and the current change value input to the negative input terminal by the gain of the differential amplifier circuit; and the buffer circuit has a second input terminal and an output terminal connected, and outputs the contact force with the target object.

13. A time-varying output circuit according to claim 9 or 10, wherein the sensor is a sensor whose resistance changes in response to an applied force.

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