Position / force control device, position / force control method and program

Abstract

[Problem] To properly learn or present the feel of an object. [Solution] A position / force controller 1 is provided with a control unit 20 and an impedance estimation unit 10. The control unit 20 acquires a parameter which is generated in the control of a position and force executed with respect to a touch on the object to be touched. The impedance estimation unit 10 estimates the impedance of the object to be touched, on the basis of the parameter acquired by the control unit 20.

Description

[Technical Field]

[0001] The present invention relates to a position / force control device, a position / force control method, and a program for controlling the position and force of a controlled object. [Background technology]

[0002] In recent years, techniques have been developed for controlling position and force to transmit the sensation of touching an object. Position and force control technologies for transmitting the sensation of touching an object are used for purposes such as enabling a robot to grasp an object with the appropriate force, or transmitting haptic sensations between the master and slave sides in a master-slave system. The technology relating to the control of position and force as described above is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 041046 Summary of the Invention [Problem to be solved by the invention]

[0004] However, while conventional technologies that control the position and force used to transmit the sensation of touching an object can transmit characteristics such as the size and hardness of an object, it has been difficult to obtain texture information that represents the feel of the object's surface or present it to the user. In particular, when presenting the user with the texture of an object that the user touches in a virtual space, the texture needs to be mechanically reproduced on the device used by the user, and such control has not been established using conventional position and force control technologies. As described above, with conventional techniques, it has been difficult to appropriately acquire or present the feel of an object, including the texture of the object. An object of the present invention is to appropriately acquire or present the feel of an object. [Means for solving the problem]

[0005] In order to solve the above problems, a position / force control device according to one aspect of the present invention comprises: a parameter acquisition means for acquiring parameters generated in the position and force control executed for contact with the object to be contacted; an impedance estimating means for estimating an impedance of the object to be contacted based on the parameters acquired by the parameter acquiring means; The present invention is characterized by comprising:

[0006] Furthermore, a position / force control device according to another aspect of the present invention comprises: a position acquisition means for acquiring a position of the object surface in a planar direction and a position in a direction perpendicular to the planar direction of the object to be contacted; a haptic sensation providing means for providing a haptic sensation including a texture representing the feel of the object surface by controlling the positions and forces output by actuators at the positions in the plane and the direction perpendicular to the plane of the object surface of the object to be contacted, which are acquired by the position acquiring means, based on a function in which the impedance of the object to be contacted is set as an eigenvalue and the positions in the plane and the direction perpendicular to the plane of the object surface are used as variables for calculating a reaction force from the object to be contacted; The present invention is characterized by comprising: [Effects of the Invention]

[0007] According to the present invention, the feel of an object can be appropriately acquired or presented. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating the concept of the feel of an object in the present invention. [Figure 2] 10A and 10B are schematic diagrams illustrating the concept of the feel of an object when it is understood that the stiffness, viscosity, and inertia change at each contact position of the object to be contacted. [Figure 3] FIG. 10 is a schematic diagram showing a state in which the impedance of an object is acquired by performing position control, velocity control, or force control. [Figure 4] 1 is a block diagram showing an example of the configuration of a position / force control device 1 when the impedance of an object is obtained by performing position control, velocity control, or force control. [Figure 5] FIG. 2 is a block diagram showing a control algorithm implemented in the control unit 20. [Figure 6] 10 is a flowchart illustrating the flow of an impedance estimation process executed by the position / force control device 1. [Figure 7] 10 is a flowchart illustrating the flow of a force and tactile sense presentation process executed by the position and force control device 1. [Figure 8] This is a schematic diagram showing how the impedance of an object is acquired by transmitting haptic sensations between a master and a slave. [Figure 9] 1 is a block diagram showing an example of the configuration of a position / force control device 1 when the impedance of an object is obtained by transmitting a force haptic sensation between a master and a slave. [Figure 10] 10 is a schematic diagram showing an example of an implementation form of the position / force control device 1 of Modification 1. FIG. [Figure 11] 10 is a block diagram showing a control algorithm implemented in a control unit 20 in Modification 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the basic principles applied to the position / force control device, the position / force control method, and the program according to the present invention will be described.

[0010] [Basic principle] The present invention acquires the haptic sensation when touching an object as information, including the texture that represents the feel of the object's surface, and presents it using a device. In the present invention, in order to obtain haptic information when touching an object, the impedance of the object to be touched is estimated. In estimating impedance, in order to perform calculations related to the haptic sensation when touching an object, real-space parameters are transformed into a coordinate system that allows position and force to be handled independently. This coordinate transformation is defined as a transformation that represents the haptic sensation control function, and for example, the coordinate transformation shown in International Publication No. 2015 / 041046 as representing the haptic sensation transmission function can be used. The concept of the haptic sensation control function includes controlling the haptic sensation felt by humans and controlling the position, speed, force, etc. output by a machine.

[0011] Then, based on the position of the actuator's output shaft (or the corresponding operating member), the input vector representing the position and force in real space is coordinate-transformed into a vector in the above-mentioned coordinate system, and in this coordinate system, a calculation is performed to make the state value (vector element) obtained by the coordinate transformation follow the target value for realizing the haptic control function. Furthermore, by converting the calculation results in the above coordinate system back into real-space parameters and controlling the actuator based on these parameters, a force-tactile control function is realized, and the impedance (rigidity, viscosity, and inertia) of the object to be contacted is estimated based on the parameters obtained in this series of controls.

[0012] Furthermore, in the present invention, the estimated impedance can be used to present the feel of the surface of an object in real space or virtual space (specifically, a haptic sensation including a texture representing the feel of the surface of the object). In order to present the feel of an object surface, in this invention, the stiffness, viscosity, and inertia (impedance) of the object to be contacted are considered to be inherent, and the reaction force from the object is defined as a function corresponding to the position in the plane of the object surface and the position in the direction perpendicular to the plane, thereby converting the texture representing the feel of the object surface into information. Specifically, the feel of the object being contacted is defined based on an equation of motion in which stiffness, viscosity, and inertia are constants, and the position that determines the action and reaction with the object is expressed as a function whose elements are the position in the plane direction of the object surface and the position in the direction perpendicular to the plane.

[0013] When the position of the object surface in the plane direction and the position in the direction perpendicular to the plane are given as input in real or virtual space, a value determined by a function that defines the feel of the object to be contacted is input as a reference value, and by performing a calculation to make it follow the target value in the above-mentioned coordinate system and controlling the output of the actuator, it is possible to present a force sensation including a texture that represents the feel of the object surface. In addition, since position and velocity (or acceleration) or angle and angular velocity (or angular acceleration) are parameters that can be replaced by differential and integral calculations, when performing processing related to position or angle, they can be replaced with velocity or angular velocity, etc. as appropriate.

[0014] [Function that represents the feel of an object] As described above, in this invention, the stiffness, viscosity, and inertia (impedance) of the object to be contacted are considered to be inherent, and the feel of the object is defined as a function corresponding to the position in the plane direction of the object surface and the position in the direction perpendicular to the plane, thereby converting the texture representing the feel of the object surface into information. The feel of an object (the haptic sensation including the texture that represents the feel of the object's surface) is affected not only by the shape of the object's surface but also by the physical properties of the object itself. Therefore, when defining the feel of an object, it is effective to reflect the impedance of the object.

[0015] FIG. 1 is a schematic diagram showing the concept of the feel of an object in the present invention. As shown in Figure 1, when the surface of the object being contacted is not smooth and flat but has minute irregularities, the impedance (rigidity, viscosity, and inertia) of the object itself does not change, but the shape (contour) of the surface is perceived as changing. In this case, it is more appropriate to consider that the parameter Z, which represents the impedance of the object, does not change, and that the reaction force from the object changes depending on the contact position (position x in the plane of the object surface and position y in the direction perpendicular to the plane). Therefore, in the present invention, the feel of an object is defined by the rigidity, viscosity, and inertia inherent to the object, and the contour information of the object's surface. Specifically, the feel of an object is defined by the following equations (1) and (2).

[0016]

number

[0017] In equations (1) and (2), f is the reaction force from the object being contacted, m is inertia, d is viscosity, k is rigidity, g is a function that represents the contour of the object's surface, and t is time. Since the function that represents the contour of the object's surface is a function of time t, equation (2) represents the contour of the object's surface, the shape of which changes in response to contact, etc. In this case, the parameters to be managed in acquiring or presenting a tactile sensation are the object's inherent rigidity, viscosity, and inertia (impedance), as well as the position of the object's surface in the plane and the position perpendicular to the plane, making it possible to acquire or present a tactile sensation with fewer parameters. Furthermore, if it is considered that the stiffness, viscosity, and inertia change at each contact position of the object being contacted (i.e., the impedance differs depending on the contact position), the stiffness, viscosity, and inertia of the object being contacted can be considered to be functions corresponding to the position in the planar direction of the surface of the contacted object.

[0018] FIG. 2 is a schematic diagram showing the concept of the feel of an object when it is considered that the stiffness, viscosity, and inertia change at each contact position of the object to be contacted. In the concept shown in FIG. 2, it is understood that impedances Z1 to Z5 change depending on the position x in the planar direction of the contacted object surface, and therefore the feel of the object is expressed by the following equation (3).

[0019]

number

[0020] In this case, since it is necessary to have data on stiffness, viscosity, and inertia for each position, the number of parameters to be managed is relatively large compared to when the feel of an object is defined using equations (1) and (2), which may increase implementation costs and the amount of calculation. Therefore, in the present invention, the texture including the feel of the object surface is handled by defining the feel of the object as in equations (1) and (2).

[0021] [composition] Next, the configuration of an apparatus to which the present invention is applied will be described. When using the method for handling textures that represent the feel of the surface of an object as described above, it is possible to present a texture that includes the feel of the object by obtaining the impedance of the object to be touched and defining it based on equations (1) and (2). The impedance of an object can be obtained, for example, from parameters in position control, velocity control, or force control when contacting the object.

[0022] FIG. 3 is a schematic diagram showing a state in which the impedance of an object is acquired by performing position control, velocity control, or force control. As shown in Figure 3, when a contactor (such as a robot hand) driven by an actuator comes into contact with an object under position control, velocity control, or force control, the reaction from the object causes the parameters generated in the control to change depending on the impedance of the object. By acquiring the series of parameters that occur at this time and substituting them into the equation of motion to find a solution, it is possible to estimate the impedance (stiffness, viscosity, and inertia) of the object being contacted. The impedance thus obtained is made specific to the object, and the actuator is controlled using the values ​​calculated by equations (1) and (2) as reference values ​​based on the position of the object surface in the planar direction and the position in the direction perpendicular to the plane (i.e., the contour information of the object surface), thereby making it possible to present a texture that includes the feel of the object.

[0023] FIG. 4 is a block diagram showing an example of the configuration of a position / force control device 1 when the impedance of an object is obtained by performing position control, velocity control, or force control. In FIG. 4, the position / force control device 1 includes an impedance estimation unit 10 , a control unit 20 , a driver 30 , an actuator 40 , a position sensor 50 , and a storage unit 60 . The position / force control device 1 refers to the reference value serving as the basis for operation stored in the memory unit 60, and performs operation according to the function represented by the coordinate transformation set in the control unit 20, using the detection result of the output shaft of the actuator 40 (or a member that operates in correspondence with the output shaft) and the reference value as input.

[0024] As will be described later, the functions implemented in the position / force control device 1 can be changed in various ways by switching the coordinate transformation defined in the functional force / velocity allocation transformation block FT of the control unit 20, and here, a position / force control function is set that realizes the operation of the actuator 40 corresponding to the operation represented by the reference value.

[0025] The storage unit 60 is configured with a storage device such as a memory or a hard disk. The storage unit 60 stores reference values ​​that serve as the basis for the operation of the position / force control device 1. In the position / force control device 1 shown in Fig. 4, the storage unit 60 stores reference values ​​that represent the operation of contacting the surface of an object and acquiring texture information including the feel of the object surface while receiving a reaction force from the object.

[0026] Furthermore, the memory unit 60 stores parameters acquired in the process of the control unit 20 performing an operation according to the function represented by the set coordinate transformation, using the detection results of the output shaft of the actuator 40 (or a member that operates in correspondence with the output shaft) and a reference value as input. Furthermore, the storage unit 60 stores functions (Equations (1) and (2)) that define the impedance and feel of the contact object estimated by the impedance estimation unit 10. Note that instead of the functions (Equations (1) and (2)) that define the impedance and feel of the contact object, table-format data calculated based on these functions may be stored.

[0027] The impedance estimation unit 10 reads out from the storage unit 60 parameters acquired in the process of performing an operation according to the function represented by the set coordinate transformation, and estimates the impedance (rigidity, viscosity, and inertia) of the contact target object. The impedance estimation unit 10 can estimate the impedance of the contact target object based on, for example, a reaction force input from the contact target object in response to the output of the actuator 40. The impedance estimation unit 10 can be configured by an information processing device such as a CPU (Central Processing Unit), and may be configured as a part of the control unit 20.

[0028] The control unit 20 controls the entire position / force control device 1, and is configured by an information processing device such as a CPU. The control unit 20 converts real-space parameters (such as the position of the output shaft of the actuator 40) into a coordinate system that allows position and force to be handled independently, and performs calculations in this coordinate system to cause the state values ​​(vector elements) obtained by the coordinate conversion to follow target values ​​for realizing the haptic control function. The control unit 20 then inversely converts the results of the calculations in the coordinate system into real-space parameters, and controls the actuator 40 based on these parameters, thereby presenting haptic sensations that include textures that represent the feel of the surface of an object.

[0029] FIG. 5 is a block diagram showing a control algorithm implemented in the control unit 20. 5, the algorithm implemented in the control unit 20 is expressed as a control law including a functional force-velocity allocation conversion block FT, at least one of an ideal force source block FC or an ideal velocity (position) source block PC, and an inverse conversion block IFT. In this embodiment, the controlled system S is composed of a driver 30 and an actuator 40.

[0030] The functional force-speed allocation transformation block FT is a block that defines the transformation of control energy into the speed (position) and force domains that are set according to the function of the controlled system S. Specifically, the functional force-speed allocation transformation block FT defines a coordinate transformation that takes as input the reference value (reference value) of the function of the controlled system S and the current position of the actuator. This coordinate transformation generally transforms an input vector whose elements are the reference value and current speed (position) into an output vector consisting of speed (position) for calculating the target speed (position) control value, and also transforms an input vector whose elements are the reference value and current force into an output vector consisting of force for calculating the target force control value.

[0031] By setting the coordinate transformation in the functional force / velocity allocation transformation block FT according to the function to be realized, it is possible to realize various actions and reproduce actions involving scaling. That is, in the basic principle of this invention, the functional force-velocity allocation transformation block FT "converts" the variables of a single actuator (variables in real space) into a group of variables of the entire system that express the functions to be realized (variables in space after coordinate transformation), and allocates control energy to the control energy of velocity (position) and the control energy of force. Therefore, compared to when control is performed using the variables of a single actuator (variables in real space), it is possible to assign the control energy of velocity (position) and the control energy of force independently. In this embodiment, the state value in the space after coordinate transformation can be calculated under the condition that the difference in position between the position calculated from the position of the actuator 40 and the reference value and the input of the force is zero and the sum of the forces is zero (an equal force is output in the opposite direction).

[0032] The Ideal Force Source Block FC is a block that performs calculations in the force domain according to the coordinate transformation defined by the Functional Force-Velocity Allocation Transformation Block FT. In the Ideal Force Source Block FC, a target value for force is set when performing calculations based on the coordinate transformation defined by the Functional Force-Velocity Allocation Transformation Block FT. This target value is set as a fixed value or a variable value depending on the function to be realized. For example, when realizing a function similar to the function indicated by the reference value, zero can be set as the target value, or when scaling is performed, a value obtained by enlarging or reducing the information indicating the function to be reproduced can be set.

[0033] The ideal velocity (position) source block PC is a block that performs calculations in the velocity (position) domain according to the coordinate transformation defined by the functional force-velocity allocation transformation block FT. In the ideal velocity (position) source block PC, a target value for velocity (position) is set when performing calculations based on the coordinate transformation defined by the functional force-velocity allocation transformation block FT. This target value is set as a fixed value or a variable value depending on the function to be realized. For example, if you want to achieve a function similar to the function indicated by the reference value, you can set zero as the target value, or if scaling is performed, you can set a value that is an enlarged or reduced version of the information indicating the function to be reproduced.

[0034] The inverse transformation block IFT is a block that converts values ​​in the domain of velocity (position) and force into values ​​in the domain of input to the controlled system S (for example, voltage values ​​or current values). Under this control algorithm, the control unit 20 receives time-series position detection values ​​detected by the position sensor 50. These time-series position detection values ​​represent the operation of the actuator 40, and the control unit 20 applies coordinate transformation set according to the function to the velocity (position) and force information derived from the input detection values ​​(position).

[0035] The driver 30 supplies specific control energy (current in this case) to the actuator 40 based on the value of the domain of the input to the actuator 40 that has been inversely converted by the control unit 20. The actuator 40 is driven by the control energy supplied from the driver 30 and controls the position of the controlled object. The position sensor 50 detects the position of the output shaft of the actuator 40 (or the controlled object), and outputs the detected value to the control unit 20.

[0036] The position / force control device 1 having the above-described configuration can set preset position and force values ​​as the reference values ​​input to the control unit 20. In other words, the position / force control device 1 can reproduce the desired function without using a master device or the like.

[0037] [Operation] Next, the operation of the position / force control device 1 will be described. [Impedance estimation processing] First, the impedance estimation process for estimating the impedance of the contact target object will be described.

[0038] FIG. 6 is a flowchart illustrating the flow of the impedance estimation process executed by the position / force control device 1. The impedance estimation process is started in response to an instruction to execute the impedance estimation process being given in the control unit 20. In step S1, the control unit 20 controls the haptic sensation based on the position of the actuator 40 detected by the position sensor 50 and the reference value stored in the storage unit 60. In step S2, the control unit 20 stores in the storage unit 60 the parameters generated in the haptic control.

[0039] In step S3, the impedance estimation unit 10 refers to the parameters generated during the haptic control stored in the storage unit 60, and estimates the impedance of the object to be contacted. In step S4, the impedance estimating unit 10 stores the estimated impedance in the storage unit 60. After step S4, the impedance estimation process ends.

[0040] [Haptic display processing] Next, a haptic sensation presentation process for presenting the feel of an object to be touched will be described. FIG. 7 is a flowchart illustrating the flow of the force and tactile sensation presentation process executed by the position and force control device 1. The force-tactile presentation process is a process that presents force-tactile sensations including textures that represent the feel of the surface of an object when touching an object in a virtual space (such as a virtual object in a game using a virtual space or a product in a virtual space sold in an e-commerce site). However, force-tactile presentation process can also be used to later reproduce the force-tactile sensation when touching an object in real space. The haptic sense presentation process is started in response to an instruction from the control unit 20 to execute the haptic sense presentation process.

[0041] In step S11, the control unit 20 acquires the contact position of the object to be contacted (contact position of the virtual object). In step S12, the control unit 20 calculates a reference value corresponding to the contact position of the object to be contacted from the definition equation of the force haptic sense (see equations (1) and (2)) in which the impedance stored in the storage unit 60 is set. In step S13, the control unit 20 converts the position of the actuator 40 and the calculated reference value into a coordinate system that allows position and force to be handled independently.

[0042] In step S14, the control unit 20 performs a calculation to make the state values ​​obtained by the coordinate transformation follow the target values ​​for realizing the haptic control function. In step S15, the control unit 20 inversely converts the calculation results in the coordinate system into parameters in real space. In step S16, the control unit 20 controls the actuator 40 based on the parameters obtained by the inverse transformation. After step S16, the haptic sense presentation process is repeated.

[0043] As described above, the position / force control device 1 according to this embodiment estimates the impedance of the contacted object based on parameters generated when the object is contacted through haptic control. The position / force control device 1 then treats the estimated impedance (stiffness, viscosity, and inertia) of the contacted object as a unique value and defines the feel of the object as a function corresponding to the position in the planar direction and the position perpendicular to the plane of the object's surface, thereby converting the texture representing the feel of the object's surface into information. Furthermore, when the position in the planar direction and the position perpendicular to the plane of the object's surface are given as inputs in real or virtual space, the position / force control device 1 inputs values ​​determined by the function defining the feel of the contacted object as reference values, performs calculations to track the reference values ​​in the coordinate system, and controls the output of the actuators to present haptics including texture representing the feel of the object's surface. Therefore, the position / force control device 1 makes it possible to appropriately obtain and present the feel of an object, including the texture of the object.

[0044] Furthermore, when the control unit 20 presents haptic sensations and emphasizes or suppresses the sensation, the texture can be enlarged or reduced and presented to the user by, for example, setting the reference value (or target value after coordinate transformation) determined based on a function that defines the sensation of the object to a value corresponding to scaling.

[0045] [Variation 1] In the above embodiment, an example of the configuration of the position / force control device 1 in the case where the impedance of an object is estimated by performing position control, velocity control, or force control has been described. On the other hand, the position / force control device 1 can also be configured to estimate the impedance of an object by transmitting haptic sensations between the master and slave.

[0046] Figure 8 is a schematic diagram showing how the impedance of an object is acquired by transmitting haptic sensations between the master and slave. As shown in Figure 8, when the slave device comes into contact with an object during haptic transmission between the master and slave, the parameters generated in the haptic transmission change depending on the impedance of the object due to the reaction force from the object. By acquiring the series of parameters that occur at this time and substituting them into the equation of motion to find a solution, it is possible to estimate the impedance (stiffness, viscosity, and inertia) of the object being contacted.

[0047] FIG. 9 is a block diagram showing an example of the configuration of a position / force control device 1 when the impedance of an object is obtained by transmitting a force haptic sensation between a master and a slave. FIG. 10 is a schematic diagram showing an example of an implementation form of the position / force control device 1 of this modified example. 9 and 10, the position / force control device 1 includes an impedance estimation unit 10, a control unit 20, a master unit 1A, and a slave unit 1B. The master unit 1A and the slave unit 1B are configured to be able to communicate with the control unit 20 via a network or the like.

[0048] Each of the master unit 1A and the slave unit 1B includes a driver 30, an actuator 40, and a position sensor 50, and these components are configured similarly to the position / force control device 1 shown in Fig. 4. The impedance estimation unit 10 and the storage unit 60 are also configured similarly to the position / force control device 1 shown in Fig. 4. The control unit 20 controls the entire position / force control device 1, and is configured by an information processing device such as a CPU.

[0049] The control unit 20 converts real-space parameters (such as the positions of the output shafts of the actuators 40 of the master unit 1A and the slave unit 1B) into a coordinate system that allows position and force to be handled independently, and performs calculations in this coordinate system to cause the state values ​​(vector elements) obtained by the coordinate conversion to follow target values ​​for realizing the haptic control function. The control unit 20 then inversely converts the results of the calculations in the coordinate system into real-space parameters, and controls the actuators 40 of the master unit 1A and the slave unit 1B based on these parameters, thereby making it possible to present haptic sensations, including textures that represent the feel of the surface of an object, in real time.

[0050] FIG. 11 is a block diagram showing a control algorithm implemented in the control unit 20 in this modification. 11, the algorithm implemented in the control unit 20 of this modified example is expressed as a control law including a functional force-velocity allocation conversion block FT, at least one of an ideal force source block FC or an ideal velocity (position) source block PC, and an inverse conversion block IFT. In this embodiment, the controlled system S is composed of the drivers 30 and actuators 40 of the master unit 1A and the slave unit 1B, respectively. The configuration of each block shown in FIG. 11 is the same as that of the control algorithm shown in FIG.

[0051] In the algorithm shown in Figure 11, the functions defined by the functional force-velocity allocation conversion block FT can realize functions such as transmitting the operation of the master unit 1A to the slave unit 1B and feeding back the reaction force input from an object to the slave unit 1B to the master unit 1A (bilateral control function). The position / force control device 1 in this modified example can also execute the impedance estimation process shown in FIG. 6, and can estimate the impedance of the object to be contacted from parameters that are generated in the process of force haptic control between the master unit 1A and the slave unit 1B. Furthermore, in the position / force control device 1 of this modified example, the force and tactile sensation presentation process shown in FIG. 7 can be executed for the master unit 1A or the slave unit 1B.

[0052] As described above, the position / force control device 1 according to this embodiment includes the control unit 20 and the impedance estimating unit 10. The control unit 20 acquires parameters generated in the position and force control executed for contact with the object to be contacted. The impedance estimation unit 10 estimates the impedance of the contact target object based on the parameters acquired by the control unit 20. This makes it possible to estimate the impedance of the object to be contacted from parameters generated during control of the position and force when the object to be contacted is directly contacted. Therefore, it is possible to properly obtain the feel of an object, including the texture of the object.

[0053] In controlling position and force, based on the position information of the member that is in contact with the object to be contacted, a conversion is made to a coordinate system in which position and force are independent, and a calculation is performed to make the state values ​​in that coordinate system follow the target values ​​of position and force.Then, an inverse conversion of the above conversion is performed on the calculation results, thereby controlling the position and force relative to the object to be contacted. This allows the impedance of the object being contacted to be estimated based on parameters generated when more accurate position and force control is performed in a coordinate system in which position and force can be handled independently.

[0054] The position / force control device 1 also includes a position sensor 50 and a control unit 20 . The position sensor 50 acquires the position of the object to be touched in the plane direction of the object surface and the position in the direction perpendicular to the plane. The control unit 20 presents a force sensation including a texture representing the feel of the object surface by controlling the position and force output by the actuator at the position in the plane and the position perpendicular to the plane of the object surface acquired by the position sensor 50, based on a function in which the impedance of the object to be contacted is used as an eigenvalue and the position in the plane and the position perpendicular to the plane of the object surface are used as variables for calculating the reaction force from the object to be contacted. This allows for the presentation of haptic sensations based on a model in which the parameters representing the impedance of an object do not change, but the reaction force from the object changes depending on the position of contact (the position in the plane of the object surface and the position perpendicular to the plane). Therefore, it is possible to appropriately present the feel of an object, including the texture of the object.

[0055] The control unit 20 presents a haptic sensation including a texture representing the feel of the object surface determined based on a function by enlarging or reducing it with respect to a position on the object surface in a planar direction and a position in a direction perpendicular to the plane. This makes it possible to present the feel of the object surface by emphasizing or suppressing it.

[0056] The present invention is not limited to the above-described embodiment, and any modifications and improvements that can achieve the object of the present invention are included in the present invention. For example, in the above-described embodiment, the case where the haptic sensation is presented using the impedance estimated by the impedance estimation process has been described as an example, but the present invention is not limited to this. For example, the haptic sensation may be presented using the results of estimating the impedance using another method or actually measuring the impedance. Furthermore, when emphasizing or suppressing the feel of the object surface, an example has been described in which the reference value (or the target value after coordinate transformation) determined based on a function that defines the feel of the object is set to a value corresponding to scaling, but this is not limiting. That is, other methods can be used as long as the feel presented to the user is emphasized or suppressed. For example, it is possible to enlarge or reduce the texture and present it to the user by applying a gain to the input to the actuator, etc.

[0057] Furthermore, the processes in the above-described embodiments can be executed by either hardware or software. That is, it is sufficient that the position / force control device 1 has the function of executing the above-mentioned processing, and the functional configuration and hardware configuration for realizing this function are not limited to the above-mentioned example. When the above-described processing is performed by software, the programs that make up the software are installed into a computer from a network or a storage medium.

[0058] The storage medium that stores the program may be a removable medium distributed separately from the device itself, or may be a storage medium that is pre-installed in the device itself. Removable media may be, for example, a magnetic disk, an optical disk, or a magneto-optical disk. Optical disks may be, for example, CD-ROMs (Compact Disk-Read Only Memory), DVDs (Digital Versatile Disks), Blu-ray Discs (registered trademark), etc. Magneto-optical disks may be, for example, MDs (Mini-Disks), etc. Furthermore, storage media that are pre-installed in the device itself may be, for example, a ROM (Read Only Memory) or hard disk in which the program is stored.

[0059] The above embodiment shows an example of application of the present invention and does not limit the technical scope of the present invention. In other words, the present invention can be modified in various ways, such as by omission or substitution, without departing from the gist of the present invention, and various embodiments other than the above embodiment can be adopted. The various embodiments and modifications that the present invention can adopt are included in the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0060] 1 Position / force control device, 10 Impedance estimation unit, 20 Control unit, 30 Driver, 40 Actuator, 50 Position sensor, 60 Memory unit, FT Functional force / velocity allocation conversion block, FC Ideal force source block, PC Ideal velocity (position) source block, IFT Inverse conversion block, S Control target system

Claims

1. A parameter acquisition means for acquiring control parameters for transmitting a reaction force from an object to be contacted, the control parameters being generated in controlling a position and a force for transmitting the reaction force from the object to a member in contact with the object; an impedance estimating means for estimating an impedance of the object to be contacted based on the control parameters acquired by the parameter acquiring means; Equipped with A position / force control device characterized in that the feeling of the object to be contacted is defined by making the estimated impedance specific to the object to be contacted and making the reaction force from the object to be contacted a function determined according to the position of the object to be contacted in a plane direction and a position in a direction perpendicular to the plane on the surface of the object to be contacted.

2. 2. The position / force control device according to claim 1, wherein the position and force control is performed by converting position information of a member in contact with the object to a coordinate system in which position and force are independent, performing a calculation to make state values ​​in the coordinate system follow target values ​​of position and force, and then performing an inverse transformation of the calculation result to control the position and force on the object to be contacted.

3. A parameter acquisition step of acquiring control parameters for transmitting a reaction force from an object to be contacted, the control parameters being generated in controlling a position and a force for transmitting the reaction force from the object to a member in contact with the object; an impedance estimating step of estimating an impedance of the object to be contacted based on the control parameters acquired in the parameter acquiring step; Including, A position / force control method characterized in that the feeling of the object to be contacted is defined by making the estimated impedance specific to the object to be contacted and making the reaction force from the object to be contacted a function determined according to the position of the object to be contacted in a plane direction and a position in a direction perpendicular to the plane on the surface of the object to be contacted.

4. On the computer, a parameter acquisition function for acquiring control parameters for transmitting a reaction force from an object to be contacted, the control parameters being generated in controlling a position and a force for transmitting the reaction force from the object to a member in contact with the object; an impedance estimation function that estimates the impedance of the object to be contacted based on the control parameters acquired by the parameter acquisition function; To achieve this, A program that defines the feel of the object to be contacted by making the estimated impedance specific to the object to be contacted and by making the reaction force from the object to be contacted a function that is determined depending on the position of the object to be contacted in a plane direction and a position in a direction perpendicular to the plane on the surface of the object to be contacted.

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