JP2007301660A - Foreign substance detection method and robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect presence/absence of a foreign substance such as a wiretap and a spy camera attached to an optional position. <P>SOLUTION: This robot 1 has joints 300, a joint 301 a joint 302 and a joint 303 rotatably connected with wheels 201, a casing 200, an upper arm 202, a forearm 203 and a hand 204 respectively. This robot 1 rotates a member with motors provided in the respective joints and detects shafting inertia moments of the motors for every joint. This robot 1 compares the values of the detected inertia moments with the inertia moments when no foreign substance is attached and determine whether the foreign substance is attached to the member or not. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a foreign object detection method and a robot, and more particularly to a foreign object detection method and a robot that detect the presence or absence of a foreign object such as a voyeur or a wiretap attached to an arbitrary part.

  In recent years, mobile robots (hereinafter referred to as “robots”) have been commercialized and have begun to spread to ordinary households. Such a robot can act autonomously according to a command from a user or a surrounding situation. In addition, the camera as a visual function to recognize the robot's work space and moving space, and people and objects in contact with the robot, and the microphone as an auditory function to hear surrounding voices and sounds to realize communication with humans Is installed.

  By the way, recently, robots that can be remotely controlled by radio or the like have come to be seen. With such a robot, it is possible to collect and shoot sound in a home or office even from a remote place by using a camera or a microphone mounted on the robot. Therefore, it is necessary to carefully consider that the unauthorized use of the robot does not infringe on the privacy of the robot user, such as eavesdropping or voyeurism, or that information that has been kept secret for business purposes is not voyeurized. .

  In consideration of this situation, while the robot is sending image information to the remote control device, it warns the outside, such as sound and light, and sends image information to surrounding people. A method for easily recognizing and preventing unauthorized use has been proposed (see, for example, Patent Document 1).

  In this method, while image information from a camera mounted on a robot is transmitted to a remote control device (for example, a personal computer having a wireless communication function), a warning is issued to the outside by voice or blinking of an LED. I am doing so.

  In addition, as a work robot, a robot has been proposed in which a force sensor is provided on the wrist of the robot body, and a plurality of tools are automatically exchanged as necessary during work.

In this robot, in order to judge the normality / abnormality of an object to be attached to and detached from the robot body, the weight / center of gravity data for each of the case where a plurality of tools are attached to the force sensor and the case where none of the tools are attached is obtained. The normality / abnormality of the replaced tool was determined based on the load value detected by the force sensor when the tool was attached or detached (see, for example, Patent Document 2).
JP 2002-331482 A JP 7-237165 A

  On the other hand, in addition to the camera and microphone mounted on the robot, wireless tapping devices and voyeurs (hereinafter referred to as “foreign objects”) are attached to the above-mentioned robot, regardless of whether the robot is remotely operated or not. It is also necessary to fully consider the possibility of eavesdropping and voyeurism in the home.

  However, with conventional robots that determine the normality / abnormality of an object that is attached to or detached from the main body, there is a problem that it is possible to determine the normality / abnormality of an object that is attached / detached only where there is a force sensor, and it cannot be determined where there is no force sensor. there were.

  This invention solves such a subject, and it aims at providing the foreign material detection method and robot which can detect the presence or absence of foreign materials, such as a wiretap and a voyeur, attached to arbitrary parts. .

  The robot according to the present invention includes a driving unit that rotates at least one of the plurality of members around a joint that connects the plurality of members, and a control unit that outputs a control signal for rotating the members with respect to the driving unit. And a detection unit for detecting the first moment of inertia around the rotation axis at the joint, and the value of the first moment of inertia and the value of the second moment of inertia around the rotation axis at the joint when no foreign matter is attached. And a foreign matter judgment unit for judging the presence or absence of foreign matter attached to at least one of the plurality of members.

  According to this configuration, it is possible to detect the presence or absence of a foreign substance attached to an arbitrary member of the robot.

  The foreign matter determination unit may determine that the foreign matter is attached when the value of the first moment of inertia is larger than the value of the second moment of inertia.

  According to this, it is further possible to detect that a foreign substance is attached to the member.

  In addition, there are a plurality of joints, the detection unit sequentially detects the first moment of inertia around the rotation axis at each of the plurality of joints, and the foreign matter determination unit detects the value of the first moment of inertia detected for each joint. The presence or absence of foreign matter may be determined for each of them, and the member to which the foreign matter is attached may be specified based on the determined determination results.

  According to this, it is possible to further specify a member to which foreign matter is attached.

  Further, the control unit may hold the driving unit related to the joint that does not detect the first moment of inertia in a predetermined posture.

  According to this, the moment of inertia around the rotation axis in the drive unit related to the joint to be detected can be specified in advance, and a value obtained by actually measuring the moment of inertia in a predetermined posture can be stored at the time of factory shipment or the like. It becomes possible. As a result, if the moment of inertia is measured and stored in the same posture as when detecting the moment of inertia, it is not only necessary to calculate the design value of the complicated moment of inertia, but at the same time the influence of design errors is also caused. Can be reduced.

  In addition, the control unit outputs a control signal for performing a predetermined rotation to the drive unit related to the joint that detects the first moment of inertia, and relates to the joint that does not detect the first moment of inertia. For the drive unit, a control signal for causing the posture to minimize the first moment of inertia around the rotation axis in the drive unit related to the joint that detects the first moment of inertia as a predetermined posture is output. You may do it.

  This further allows the robot to take a posture that minimizes the moment of inertia so as to suppress the influence of the member that does not detect the rotational movement of the member that detects the presence or absence of foreign matter adhesion. , Foreign matter can be detected more easily.

  Further, the control unit may hold a member that does not detect the first moment of inertia in a stationary state.

  According to this, the member can be moved and brought into contact with a stationary structure such as a wall or a floor to be temporarily fixed, and the vibration generated by the rotated member when the moment of inertia is detected. The detection error can be reduced.

  The apparatus further includes a member fixing portion for holding at least one of the plurality of members that do not detect the first moment of inertia in a stationary state, and the detection portion is at least one of the plurality of members by the member fixing portion. The first moment of inertia may be detected after the member is held stationary.

  According to this, the member that does not detect the moment of inertia can be temporarily fixed by the member fixing portion according to the location of the member that specifies the presence or absence of a foreign object, and vibrations such as shaking of the robot body can be generated. The detection error can be reduced.

  Moreover, you may further provide the foreign material treatment part which removes a foreign material from the member pinpointed that the foreign material has adhered in the foreign material determination part.

  According to this, the foreign matter adhering to the specified member can be further removed.

In addition, the detection unit calculates the first moment of inertia J,
T = J × α + D × ω
(T: torque, α: rotational angular acceleration, D: viscous friction coefficient, ω: rotational angular velocity)
Detection may be performed based on the relational expression.

  According to this, furthermore, the moment of inertia J can be detected based on the equation of motion of rotational motion. As a result, as compared with the case of detecting with a static moment, the field of detecting foreign matter using the moment of inertia increases the moment of inertia J relatively even with a small amount of foreign matter as the rotational angular acceleration is increased. And detection accuracy can be increased.

  In addition, a temperature detection unit that detects the temperature of the joint is further provided. The detection unit corrects the torque T or the viscous friction coefficient D in the relational expression based on the temperature detected by the temperature detection unit, and the first moment of inertia. J may be detected.

  According to this, the relational expression can be further corrected according to the change in the joint temperature. As a result, it is possible to suppress errors due to a change in viscous friction coefficient due to temperature-dependent grease and a change in temperature-dependent motor torque, and to detect foreign matter with high accuracy.

  Also, the foreign object detection method of the present invention uses a robot including a plurality of members, a joint connecting the plurality of members, and a drive unit that rotates at least one of the plurality of members around the joint. In the foreign object detection method, a driving step of rotating at least one of a plurality of members around the joint by a driving unit, a control step of outputting a control signal for rotating the member to the driving unit, and a joint The detection step for detecting the first moment of inertia around the rotation axis of the first and the second moment of inertia around the rotation axis at the joint when no foreign matter is attached to the detection step And a foreign matter judgment step for judging the presence or absence of foreign matter attached to at least one of the plurality of members.

  According to this method, it is possible to detect the presence or absence of a foreign substance adhering to the member.

  In the foreign matter judgment step, the value of the moment of inertia detected in the detection step is compared with the value of the moment of inertia around the rotation axis at the joint when no foreign matter is attached. When the value is large, it may be determined that foreign matter is attached.

  According to this, it is further possible to detect that a foreign substance is attached to the member.

  The foreign matter determination step may determine that the foreign matter is attached when the value of the first moment of inertia is larger than the value of the second moment of inertia.

  According to this, it is possible to further specify a member to which foreign matter is attached.

  ADVANTAGE OF THE INVENTION According to this invention, the foreign material detection method and robot which can detect the presence or absence of foreign materials, such as a wiretap and a voyeur device attached to arbitrary parts, can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The robot according to the embodiment of the present invention rotates a member around a joint connecting a plurality of members and detects the moment of inertia around the rotation axis at the joint, thereby detecting the value of the detected moment of inertia and the amount of foreign matter. The value of the moment of inertia around the rotation axis at the joint when there is no adhesion is compared to determine the presence or absence of foreign matter adhering to a plurality of members. Further, the moment of inertia around the rotation axis at each of the joints of the plurality of members is sequentially detected, and the presence / absence of adhesion of foreign matter is determined based on the value of the detected moment of inertia for each joint. Based on the determination result, the member to which the foreign matter is attached is specified.

  In the present embodiment, a robot equipped with a manipulator composed of a hand having a finger for grasping an object in an inverted two-wheeled moving unit and two arms for changing the position of the hand, and capable of moving in a home is provided. This will be described as an example.

  Hereinafter, the configuration of the robot will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a configuration of a robot according to an embodiment of the present invention.

  As shown in FIG. 1, the robot 1 includes a casing 200 serving as a base, a pair of wheels 201, an upper arm 202, a forearm 203, and a hand 204 for grasping an object.

  A motor (not shown) is provided in each of the joint 300, the joint 301, the joint 302, and the joint 303 that are rotatably connected to each other. The motor generates a predetermined torque by the driving current and rotates each member. In addition, you may have a mechanism which amplifies and transmits the torque around the shaft of a motor to another rotating shaft with a gearwheel or a wire. Such a drive mechanism can be configured using a widely known mechanism.

  The wheel 201 and the housing 200 are connected to each other at a joint 300 by a motor (not shown). The robot 1 moves by rotating a motor and rotating a wheel 201 connected to the motor.

  The robot 1 moves to the destination while detecting its own position by comparing the position information of the map stored in advance in the robot 1 with the position information using the odometry based on the rotation detection of the wheels 201 by movement control. To do. Information such as external environment recognition by an ultrasonic sensor may be used.

  The upper arm 202 and the housing 200 are connected to each other at a joint 301 through a shaft of a motor (not shown). Further, the upper arm 202 rotates around the joint 301 connected to the housing 200 by the rotation of the motor.

  The forearm 203 and the upper arm 202 are connected to each other at the joint 302 via a shaft of a motor (not shown). Further, the forearm 203 rotates around the joint 302 connected to the upper arm 202 by the rotation of the motor.

  The hand 204 is configured to hold an object with two fingers, for example, and is connected to a forearm 203 via a shaft of a motor (not shown) at a joint 303. Further, the hand 204 rotates around the joint 303 connected to the forearm 203 by the rotation of the motor. In the manipulation, for example, the position of the gripping object is recognized by the mounted image recognition device, the postures of the upper arm 202, the forearm 203, and the hand 204 are controlled to perform gripping control.

  Next, the foreign matter detection unit in the robot 1 will be described.

  The foreign matter detection unit is provided in the robot 1 and detects the presence or absence of foreign matter attached to each member. The foreign matter detection unit drives a motor provided in each joint for foreign matter detection, and detects the moment of inertia around the rotation axis for each joint.

  The foreign matter detection unit compares the detected value of the moment of inertia with the moment of inertia when no foreign matter is attached, and determines whether there is a foreign matter attached to the member. Here, the foreign matter detection unit detects that there is a foreign matter attached to the member by utilizing the fact that the value of the moment of inertia of the member is larger than when no foreign matter is attached due to the mass of the foreign matter.

  Hereinafter, the foreign object detection unit will be described with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the foreign object detection unit.

  In FIG. 2, the foreign object detection unit drives a movement control unit 150 that performs control for moving the robot 1 body, a hand control unit 160 that performs control for gripping an object with the hand 204, and a wheel 201. In order to detect a foreign object, a wheel foreign object detection unit 10 that detects a foreign object, an upper arm foreign object detection unit 20 that detects a foreign object by driving the upper arm 202, a forearm foreign object detection unit 30 that detects a foreign object by driving a forearm 203 The foreign object detection control unit 100 that outputs the control signal to the wheel foreign object detection unit 10, the upper arm foreign object detection unit 20, and the forearm foreign object detection unit 30, and the foreign object treatment unit 140 that performs a treatment when a foreign object is detected.

  First, the wheel foreign object detection unit 10 detects the presence or absence of a foreign object by detecting the moment of inertia at the joint 300.

  The wheel foreign object detection unit 10 includes a wheel drive unit 110, a wheel angular velocity detection unit 112, a wheel detection unit 113, a wheel determination unit 114, and a wheel temperature detection unit 115.

  In response to a control signal from the foreign object detection control unit 100, the wheel drive unit 110 gives a drive current to a set of wheel motors 111 provided in the joint 300 that connects the wheel 201 and the housing 200, Rotate. The rotation instruction of the wheel motor 111 is issued from the foreign object detection control unit 100. If the wheel 201 is braked or brought into contact with a stationary structure such as a wall to temporarily fix it to the wall or the ground, it can be rotated. it can. Further, the pair of wheel motors 111 can perform the same rotation synchronously or can rotate differently. Thus, when the robot 1 is moved, the robot 1 can move straight, meander, or change direction to the left and right according to a rotation instruction from the foreign object detection control unit 100.

  The wheel drive unit 110 raises the rotational speed of the wheel motor 111 to a predetermined rotational angular speed while performing speed control according to the rotation instruction. The wheel drive unit 110 can also lock the wheel motor 111 at a predetermined rotation angle by positioning control. By switching the control, the wheel driving unit 110 can rotate or lock the wheel 201 connected to the wheel motor 111. Locking refers to a state in which members connected at each joint are fixed at a predetermined rotation angle.

  The wheel angular velocity detection unit 112 detects the rotational angular velocity around the axis of the wheel motor 111. From the detected rotational angular velocity, the rotational angular acceleration can be further obtained by differential calculation. By substituting the detected rotational angular velocity and rotational angular acceleration into an equation of motion based on a dynamic model of the rotating system, it is possible to detect the moment of inertia. Details of the method of detecting the moment of inertia will be described later.

  The wheel temperature detector 115 detects the temperature around the shaft of the wheel motor 111. By detecting this temperature, for example, when the properties of the grease applied to the rotating shaft of the wheel motor 111 change depending on the temperature, and the viscous friction coefficient changes, the viscous friction coefficient of the equation of motion depends on the temperature. It becomes possible to correct. Similarly, when the torque characteristics of the motor change with temperature, the torque constant of the equation of motion can be corrected according to the temperature.

  It should be noted that the wheel temperature detection unit 115 can be omitted by using a member or material that has little temperature dependency in the temperature range assumed in the environment where the robot is used, that is, characteristics and properties are stable.

  The wheel detection unit 113 includes a calculation unit (not shown) that calculates a moment of inertia from an equation of motion based on a dynamic model of a rotating system including the wheel motor 111. The wheel detection unit 112 includes a driving current for the wheel motor 111 and a wheel angular velocity detection unit 112. From the detected rotational angular velocity around the axis of the wheel motor 111, the moment of inertia around the axis of the wheel motor 111 is detected, and the detected value is output. At this time, the upper arm 202, the forearm 203, and the housing 200 are held stationary. Details of the method of detecting the moment of inertia will be described later. Further, the wheel detection unit 113 may correct a constant depending on the temperature in the equation of motion according to the temperature around the shaft of the wheel motor 111 detected by the wheel temperature detection unit 115. Thereby, the precision which detects a moment of inertia can be raised. As constants depending on temperature, there are constants related to motor torque, constants related to viscous friction, and the like.

  The wheel determination unit 114 stores the value of the moment of inertia around the axis of the wheel motor 111 when no foreign matter is attached to the robot 1 as a stored value in advance. The wheel determination unit 114 compares the detected value of the moment of inertia output from the wheel detection unit 113 with the stored value of the moment of inertia stored in advance, and if the detected value is larger than the stored value, “there is a foreign matter attached. If the detected value is the same as the stored value, it is determined that there is no foreign matter attached, and the determination result is output. Here, it is assumed that “1” is output when it is determined that “foreign matter is attached”, and “0” is output when it is determined that “foreign matter is not attached”.

  When comparing the detected value with the stored value, the presence or absence of a foreign object may be determined when a difference greater than a predetermined difference is detected.

  As described above, the wheel foreign object detection unit 10 detects the presence or absence of a foreign object by detecting the moment of inertia at the joint 300.

  Next, the upper arm foreign object detector 20 detects the presence or absence of a foreign object by detecting the moment of inertia at the joint 301.

  The upper arm 202 and the housing 200 are connected by an upper arm motor 121 at a joint 301. The upper arm 202 rotates around the joint 301 by the rotation of the upper arm motor 121.

  The upper arm foreign matter detection unit 20 includes an upper arm drive unit 120, an upper arm angular velocity detection unit 122, an upper arm detection unit 123, an upper arm determination unit 124, and an upper arm temperature detection unit 125.

  In response to a control signal from the foreign object detection control unit 100, the upper arm driving unit 120 applies a driving current to the upper arm motor 121 provided in the joint 301 that connects the upper arm 202 and the housing 200 to rotate the upper arm 202. An instruction to rotate the upper arm motor 121 is issued by the foreign object detection control unit 100. At this time, the joint 300, the joint 302, and the joint 303 are controlled to move in a stationary state.

  In response to the rotation instruction, the upper arm driving unit 120 raises the rotation speed of the upper arm motor 121 to a predetermined rotation angular speed while performing speed control. The upper arm drive unit 120 can also lock the upper arm motor 121 at a predetermined rotation angle by positioning control. By switching the control, the upper arm driving unit 120 can rotate or lock the upper arm 202 connected to the upper arm motor 121.

  The upper arm angular velocity detection unit 122 detects the rotational angular velocity around the axis of the upper arm motor 121.

  The upper arm temperature detection unit 125 detects the temperature around the shaft of the upper arm motor 121.

  The upper arm detection unit 123 includes a calculation unit (not shown) that calculates a moment of inertia from an equation of motion based on a dynamic model of a rotating system including the upper arm motor 121, and includes a drive current for the upper arm motor 121 and an upper arm angular velocity detection unit 122. From the detected rotational angular velocity around the axis of the upper arm motor 121, the moment of inertia around the axis of the upper arm motor 121 is detected, and the detected value is output. Further, the upper arm detection unit 123 may correct a temperature-dependent constant in the equation of motion according to the temperature around the axis of the upper arm motor 121 detected by the upper arm temperature detection unit 125.

  The upper arm determination unit 124 stores in advance the value of the moment of inertia around the axis of the upper arm motor 121 when no foreign matter is attached to the robot as a stored value. The upper arm determination unit 124 compares the detected value of the inertia moment output from the upper arm detection unit 123 with the stored value of the inertia moment stored in advance, and if the detected value is larger than the stored value, “there is a foreign matter attached. If the detected value is the same as the stored value, it is determined that there is no foreign matter attached, and the determination result is output. Here, “1” is output when it is determined that “foreign matter is attached”, and “0” is output when it is determined that “no foreign matter is attached”.

  As described above, the upper arm foreign object detection unit 20 detects the presence or absence of a foreign object by detecting the moment of inertia at the joint 301.

  Next, the forearm foreign object detection unit 30 similarly detects the presence or absence of a foreign object by detecting the moment of inertia at the joint 302.

  The upper arm 202 and the forearm 203 are connected by a forearm motor 131 at a joint 302. The forearm 203 rotates around the joint 302 by the rotation of the forearm motor 131.

  The forearm foreign object detection unit 30 includes a forearm drive unit 130, a forearm angular velocity detection unit 132, a forearm detection unit 133, a forearm determination unit 134, and a forearm temperature detection unit 135.

  In response to a control signal from the foreign object detection control unit 100, the forearm drive unit 130 applies a drive current to the forearm motor 131 provided in the joint 302 that connects the forearm 203 and the upper arm 202 to rotate the forearm 203. The rotation instruction of the forearm motor 131 and the timing thereof are issued from the foreign object detection control unit 100.

  The forearm drive unit 130 raises the number of rotations of the forearm motor 131 to a predetermined rotation angular speed while performing speed control according to a rotation instruction. The forearm drive unit 130 can also lock the forearm motor 131 at a predetermined rotation angle by positioning control. By switching the control, the forearm drive unit 130 can rotate or lock the forearm 203 connected to the forearm motor 131.

  The forearm angular velocity detector 132 detects the rotational angular velocity around the axis of the forearm motor 131.

  The forearm temperature detector 135 detects the temperature around the shaft of the forearm motor 131.

  The forearm detection unit 133 includes a calculation unit (not shown) that calculates a moment of inertia from an equation of motion based on a dynamic model of a rotating system including the forearm motor 131. The forearm motor 131 includes a driving current for the forearm motor 131 and a forearm angular velocity detection unit 132. From the detected rotational angular velocity around the axis of the forearm motor 131, the moment of inertia around the axis of the forearm motor 131 is detected, and the detected value is output. Further, the forearm detection unit 133 may correct a temperature-dependent constant in the equation of motion according to the temperature around the shaft of the forearm motor 131 detected by the forearm temperature detection unit 135.

  The forearm determination unit 134 stores in advance the value of the moment of inertia about the axis of the forearm motor 131 when a foreign object is not attached to the robot as a stored value. The forearm determination unit 134 compares the detected value of the moment of inertia output from the forearm detection unit 133 with the stored value of the moment of inertia stored in advance, and if the detected value is larger than the stored value, “foreign matter is attached. If the detected value is the same as the stored value, it is determined that there is no foreign matter attached, and the determination result is output. Here, “1” is output when it is determined that “foreign matter is attached”, and “0” is output when it is determined that “no foreign matter is attached”.

  As described above, the forearm foreign object detection unit 30 detects the presence or absence of a foreign object by detecting the moment of inertia at the joint 302.

  Next, the movement control unit 150 controls the robot 1 to move to a place where a wheel stopper for fixing the wheel 201 is installed when foreign matter detection is performed.

  The movement control unit 150 is instructed to start moving by the foreign object detection control unit 100. The movement control unit 150 returns completion of movement to the foreign object detection control unit 100 when the wheel 201 is fixed to the wheel stopper.

  In response to an instruction from the foreign object detection control unit 100, the hand control unit 160 moves the posture of the hand 204 and the finger to a predetermined state and locks them.

  The foreign object detection control unit 100 instructs the movement control unit 150 to move to the wheel stop when the robot 1 performs foreign object detection. Further, the foreign object detection control unit 100 instructs the hand control unit 160 to lock the hand 204 in a predetermined posture. Further, the foreign object detection control unit 100 instructs the wheel driving unit 110, the upper arm driving unit 120, the forearm driving unit 130, and the hand control unit 160 to rotate and lock the motor, and perform foreign object detection and foreign object removal.

  The foreign object treatment unit 140 determines the presence / absence of foreign matter attached to each member based on the determination results from the wheel determination unit 114, the upper arm determination unit 124, and the forearm determination unit 134. Further, according to the determination result, the foreign object treatment unit 140 ends the foreign object detection and allows the robot 1 to move to another operation when “no foreign object is attached”. Specifically, the robot 1 returns from the wheel stop position to a position where it is normally used, and receives an instruction from the user.

  On the other hand, in the case of “attachment of foreign matter”, the foreign matter treatment unit 140 indicates that the foreign matter is attached due to a sound such as a buzzer, light from an LED, display on a monitor, etc. This information is notified to the user. Furthermore, when the position where the foreign matter is attached and can be removed by the hand 204, the foreign matter detection control unit 100 is instructed to remove the foreign matter. Accordingly, the foreign object detection control unit 100 instructs the wheel driving unit 110, the upper arm driving unit 120, the forearm driving unit 130, and the hand control unit 160 to rotate and lock the motor, and remove the foreign objects. If the foreign matter cannot be removed, the operation of the robot 1 may be prohibited until the foreign matter is removed. In this case, the foreign substance is removed by the user of the robot 1, for example. After removing the foreign matter, the user sets the robot 1 as information that the foreign matter has been removed.

  Note that the wheel angular velocity detection unit 112, the upper arm angular velocity detection unit 122, and the forearm angular velocity detection unit 132 are indispensable for movement control even as a manipulation of the robot 1.

  Next, the foreign object detection operation in the robot 1 will be described with reference to FIGS.

  FIG. 3 is a flowchart for explaining the foreign object detection operation in the robot 1, FIG. 4 (a) is an explanatory view for explaining the posture of the robot 1 when detecting a foreign object on a wheel, and FIG. 4 (b) is a robot when detecting a foreign object on the upper arm. FIG. 4C is an explanatory diagram for explaining the posture of the robot 1 when the forearm is detected.

  As shown in FIG. 3, the robot 1 uses the foreign object detection control unit 100 to send a foreign object detection operation instruction to the movement control unit 150, the hand control unit 160, the wheel foreign object detection unit 10, the upper arm foreign object detection unit 20, and the forearm foreign object detection unit. 30.

  First, the robot 1 moves to a place for foreign object detection according to an instruction from the movement control unit 150. As shown in FIG. 4A, the robot 1 moves to the place of the wheel stopper 210 (S401), and fixes the wheel 201 to the ground by the wheel stopper 210 (S402). The wheel stopper 210 is installed on the ground (corresponding to the floor in the house) separately from the robot 1 for each of the pair of wheels 201. The wheel stopper 210 sandwiches the wheel 201 from both sides of the plane of rotation of the wheel 201 and fixes it to the floor or the ground so that the wheel 201 does not rotate due to frictional force. The wheel stopper 210 may detect that the wheel 201 has come between the wheel stoppers 210 and sandwich the wheel 201. Alternatively, the distance between the wheel stops 210 may be set to be gradually narrowed, and the wheel 201 may be fixed by pressing the wheel 201.

  In addition, in order to fix the housing | casing 200, the mechanism part which enables the wheel 201 itself to move up and down is provided, and the housing | casing 200 may be contact | abutted and fixed to a floor surface etc. by raising the wheel 201. FIG.

  Further, a part of the member that does not detect the moment of inertia may be fixed in contact with a wall or the like. You may make it fix by grasping the thing currently fixed with the finger of hand 204. FIG.

  Next, the robot 1 takes a posture for detecting the presence or absence of a foreign object by detecting the moment of inertia at the joint 300.

  The robot 1 uses the forearm drive unit 130, the upper arm drive unit 120, and the hand control unit 160 that are instructed by the foreign object detection control unit 100 to rotate the forearm motor 131, the upper arm motor 121, and the hand 204, and is suitable for foreign object detection. Move to the correct posture and lock (S403).

  As shown in FIG. 4A, the robot 1 locks the upper arm 202, the forearm 203, and the hand 204 in a folded position in order to minimize the moment of inertia about the axis of the wheel motor 111, and rotates the rotation center of the wheel motor 111. Reduce the radius range of the mass point from.

  Next, the robot 1 detects the temperature around the shaft of the wheel motor 111 by the wheel temperature detection unit 115, and corrects a constant depending on the temperature in the dynamic model according to the detected value (S404).

  Next, the robot 1 causes the wheel drive unit 110 to rotate the wheel motor 111 (S405). At this time, since the wheel 201 is fixed to the ground by the wheel stopper 210, the case 200 side rotates around the axis of the wheel motor 111 by the rotation of the wheel motor 111. Thereby, if the rotational angular velocity around the axis of the wheel motor 111 is detected, it is possible to detect the moment of inertia of the members including the casing 200, the upper arm 202, the forearm 203, and the hand 204 that rotate together.

  Next, the wheel angular velocity detector 112 detects the rotational angular velocity around the axis of the wheel motor 111. Furthermore, the wheel detection unit 113 detects the moment of inertia around the axis of the wheel motor 111 based on the torque generated in the wheel motor 111 according to the drive current output from the wheel drive unit 110 and the detected rotational angular velocity. A value is output (S406).

  Next, the robot 1 stores the detected value of the inertia moment output from the wheel detection unit 113 and the moment of inertia when no foreign matter is attached to the inertial moment about the axis of the wheel motor 111 by the wheel determination unit 114. The value is compared, and it is determined whether or not the detected value is larger than the stored value. Thereby, the wheel determination part 114 detects the presence or absence of the adhered foreign material. If the detected value is larger than the stored value, the wheel determining unit 114 outputs “1” determined to be “foreign matter adhered”, and if the detected value is smaller than the stored value, it is determined to be “no foreign matter adhered”. “0” is output as the determination result (S407).

  As described above, the robot 1 can detect the presence or absence of foreign matter by detecting the moment of inertia at the joint 300.

  Next, the robot 1 takes a posture for detecting the presence or absence of a foreign object by detecting the moment of inertia at the joint 301.

  The robot 1 uses the forearm drive unit 130, the wheel drive unit 110, and the hand control unit 160, which are instructed by the foreign object detection control unit 100, to rotate the forearm motor 131, the wheel motor 111, and the hand 204, and is suitable for foreign object detection. Move to the correct posture and lock (S408).

  As shown in FIG. 4B, the robot 1 locks the forearm 203 and the hand 204 in a folded position to minimize the moment of inertia about the axis of the upper arm motor 121, and the mass point from the rotation center of the upper arm motor 121. Reduce the radius range.

  Next, the robot 1 detects the temperature around the axis of the upper arm motor 121 by the upper arm temperature detection unit 125, and corrects a constant depending on the temperature in the dynamic model according to the detected value (S409).

  Next, the robot 1 causes the upper arm driving unit 120 to rotate the upper arm motor 121 (S410). At this time, the housing 200 and the wheels 201 are fixed, and the forearm 203 and the hand 204 rotate together with the upper arm 202 by locking. Thus, if the rotational angular velocity around the axis of the upper arm motor 121 is detected, the moment of inertia of the members including the upper arm 202, the forearm 203, and the hand 204 that rotate together can be detected.

  Next, the upper arm angular velocity detection unit 122 detects the rotational angular velocity of the upper arm motor 121. Further, the upper arm detection unit 123 detects the moment of inertia around the axis of the upper arm motor 121 based on the torque generated in the upper arm motor 121 according to the drive current output from the upper arm driving unit 120 and the detected rotational angular velocity. A value is output (S411).

  Next, the robot 1 stores the detected value of the inertia moment output by the upper arm detection unit 123 and the inertia moment in a state where no foreign matter is attached to the inertial moment around the axis of the upper arm motor 121 by the upper arm determination unit 124. The value is compared, and it is determined whether or not the detected value is larger than the stored value. As a result, the upper arm determination unit 124 detects the presence or absence of attached foreign matter. When the detected value is larger than the stored value, the upper arm determining unit 124 outputs “1” that is determined as “foreign matter adhered”, and when the detected value is smaller than the stored value, it is determined as “no foreign matter adhered”. “0” is output as the determination result (S412).

  As described above, the robot 1 detects the presence or absence of a foreign object by detecting the moment of inertia at the joint 301.

  Next, the robot 1 takes a posture for detecting the presence or absence of a foreign object by detecting the moment of inertia at the joint 302.

  The robot 1 uses the upper arm drive unit 120, the wheel drive unit 110, and the hand control unit 160 that are instructed by the foreign object detection control unit 100 to rotate the motors of the upper arm motor 121, the wheel motor 111, and the hand 204, and is suitable for foreign object detection. The posture is moved and locked (S413).

  As shown in FIG. 4 (c), the robot 1 locks the hand 204 in a folded position to minimize the moment of inertia around the axis of the forearm motor 131, and the radius range of the mass point from the center of rotation of the forearm motor 131. Make it smaller.

  Next, the robot 1 detects the temperature around the axis of the forearm motor 131 by the forearm temperature detection unit 135, and corrects a constant depending on the temperature in the dynamic model according to the value (S414).

  Next, the robot 1 causes the forearm drive unit 130 to rotate the forearm motor 131 (S415). At this time, the housing 200, the wheels 201, and the upper arm 202 are fixed, and the hand 204 rotates together with the forearm 203. Thereby, if the rotational angular velocity around the axis of the forearm motor 131 is detected, the moment of inertia of the member including the forearm 203 and the hand 204 that rotate together can be detected.

  Next, the forearm angular velocity detector 132 detects the rotational angular velocity of the forearm motor 131. Further, the forearm detection unit 133 detects and detects the moment of inertia around the axis of the forearm motor 131 based on the torque generated in the forearm motor 131 according to the drive current output by the forearm drive unit 130 and the detected rotational angular velocity. A value is output (S416).

  Next, the robot 1 stores the detected value of the inertia moment output by the forearm detection unit 133 and the moment of inertia when no foreign matter is attached to the inertial moment about the axis of the forearm motor 131 by the forearm determination unit 134. The value is compared, and it is determined whether or not the detected value is larger than the stored value. As a result, the forearm determination unit 134 detects the presence or absence of a foreign object. The forearm determination unit 134 outputs “1” determined as “the foreign matter is attached” when the detected value is larger than the stored value, and determines as “the foreign matter is not attached” when the detected value is smaller than the stored value. The determination result of “0” is output (S417).

  As described above, the robot 1 detects the presence or absence of foreign matter by detecting the moment of inertia at the joint 302.

  Next, the robot 1 uses the foreign object treatment unit 140 to determine the presence or absence of foreign objects based on the output of the determination results of the wheel determination unit 114, the upper arm determination unit 124, and the forearm determination unit 134, and further specify the location. At this time, if all the determination result outputs are “0”, it is determined that “foreign matter is not attached”, and if any determination result is “1”, it is determined that “foreign matter is attached” (S418).

  If the robot 1 determines that “no foreign matter is attached”, the robot 1 releases the wheel stopper 210 of the wheel 201, moves to a place where normal operation is performed, receives a user operation instruction, and ends foreign matter detection (S419). ).

  On the other hand, when the robot 1 determines that “foreign matter is attached”, it notifies the presence of the attached foreign matter by a buzzer or a monitor display (S420), and prohibits the movement until the foreign matter is removed. If the foreign matter can be removed by the hand 204, the foreign matter is removed (S421).

  The foreign substance treatment unit 140 has determined whether or not the foreign substance has adhered to the main body of the robot 1. However, the foreign substance treatment unit 140 further specifies the region based on the output of the determination results of the wheel determination unit 114, the upper arm determination unit 124, and the forearm determination unit 134. May be. For example, when the determination results of the wheel determination unit 114, the upper arm determination unit 124, and the forearm determination unit 134 are “1”, “0”, and “0”, respectively, there is no adhesion of foreign matter beyond the upper arm 202. Since it understands, it can identify that the foreign material has adhered to the housing | casing 200. FIG. In addition, when the determination results are “1”, “1”, and “0”, respectively, it can be specified that a foreign substance is attached to the casing 200 or the upper arm 202. Thus, the site | part to which the foreign material has adhered can be specified by using the determination result detected sequentially.

  By notifying the position of the identified foreign matter, the user can easily find and remove the foreign matter even if the foreign matter is attached to a site that is difficult to find by appearance. Furthermore, if it is possible to remove the foreign object with a finger with the hand 204 provided in the robot 1, a removal procedure can be performed. It may be removed by vibration of the arm.

  Further, even if the inertia moment around the axis of the wheel motor 111 is not detected for each part, for example, only the inertia moment around the axis of the wheel motor 111 is detected, and whether or not the steps S408 to S417 are omitted, the presence or absence of foreign matters on the main body of the robot 1 is determined. it can.

  Further, if the detection is performed separately for each part, the increase in the moment of inertia due to the adhesion of foreign matter can be relatively increased, and the presence or absence of foreign matter adhesion can be determined with higher accuracy.

  In addition, the wheel 201 is fixed to the floor surface by the wheel stopper 210 and the moment of inertia of the part other than the wheel 201 is detected. On the contrary, the wheel 201 is rotated by fixing the casing 200 to the floor surface. The moment of inertia of the wheel 201 may be detected.

  Specifically, the case 200 may be provided with a telescopic leg, and the robot 1 may fix the case 200 to the floor surface by extending the leg until the wheel 201 floats. The robot 1 can detect the moment of inertia of the wheel 201 by rotating the wheel 201 after fixing the casing 200 to the floor surface. As a result, the robot 1 can detect the presence or absence of foreign matter attached to the wheel 201.

  Thus, inertia such as a mechanism unit for moving the wheel 201 up and down to fix the housing 200, an extendable leg provided in the housing 200 for floating the wheel 201, a wheel stopper 210 for fixing the wheel 201, etc. By providing a member fixing portion (not shown) for fixing a member that does not detect a moment, it is possible to prevent a shake that occurs when the member is rotated when detecting the moment of inertia, and to reduce detection errors.

  In this way, by holding the member that does not detect the moment of inertia in a stationary state, it is possible to prevent the robot body from shaking due to the rotated member when detecting the moment of inertia, and to reduce detection errors. Further, the location of the foreign matter can be accurately identified by changing the member to be stationary according to the location of the member that identifies the presence or absence of the foreign matter.

  Further, the robot 1 may perform foreign object detection after charging of the mounted battery, or may be performed when the robot 1 is in a standby state in which no work is being performed. You may carry out when it continues more than predetermined time.

  In the robot 1, when foreign matter detection is performed after the end of charging, charging is performed periodically, so that it is not overlooked for a long time that foreign matter is attached. Further, if charging is performed at the place of the wheel stop 210, the movement to S401 can be omitted, and the time required for the movement can be shortened.

  In the robot 1, if the foreign object detection is performed in the standby state, the work efficiency is not lowered.

  Moreover, although the case where abnormality does not generate | occur | produce from S401 to S421 was demonstrated, the case where inertia moment cannot be detected normally, for example, abnormality of a motor, the collision with obstacles, such as a forearm 203, is assumed. In order to avoid this, an abnormality of the robot 1 may be detected using a sensor for detecting a rotation angle, a sensor for detecting a collision, a sensor for detecting a failure, and the like, and the foreign object detection may be stopped.

  Next, a method for detecting the moment of inertia will be described in detail.

  In a DC motor, the input current to the motor is the time variable I, the motor rotational angular velocity is the time variable ω, the motor rotational angular acceleration is α, the motor torque constant is K, the moment of inertia around the motor rotation axis is J, the viscosity Assuming that the friction coefficient is D, the torque T is known to be expressed by the following equation of motion.

T = K × I
= J × α + D × ω
In the present embodiment, the current I is a drive current given to the wheel motor 111, the upper arm motor 121, and the forearm motor 131 by the wheel driving unit 110, the upper arm driving unit 120, and the forearm driving unit 130, respectively.

  The rotational angular velocity ω is a detection signal detected by the wheel angular velocity detection unit 112, the upper arm angular velocity detection unit 122, and the forearm angular velocity detection unit 132. The rotation angular acceleration α is obtained by differentiating the rotation angular velocity ω.

  Further, the torque constant K, the viscous friction coefficient D, and the moment of inertia J are known at the stage of designing the robot 1. Thereby, if a foreign substance adheres to the member of the robot 1, the value of the moment of inertia J becomes larger than the design value due to the weight of the foreign substance. By detecting this change in the moment of inertia J, it is possible to determine the adhesion of foreign matter.

  Thus, by detecting the foreign matter using the moment of inertia, the greater the rotational angular acceleration, the larger the moment of inertia J can be made even with a foreign matter having a small mass, and the detection accuracy can be improved. . This effect cannot be obtained with a static moment.

  Further, the wheel detection unit 113, the upper arm detection unit 123, and the forearm detection unit 133 obtain the rotation angular acceleration α from the input rotation angular velocity ω, and are determined by the drive current I, the known torque constant K, and the viscous friction coefficient D. The moment of inertia J can be detected from the equation of motion by the least square method or the like. As the detection method, various known methods may be applied without depending on the least square method.

  Further, the wheel determination unit 114, the upper arm determination unit 124, and the forearm determination unit 134 may obtain a design value of the moment of inertia based on the dynamic model of the posture of the robot 1 and store it as a stored value. In addition, the wheel determination unit 114, the upper arm determination unit 124, and the forearm determination unit 134 cause the robot 1 to have a posture for detecting the moment of inertia beforehand at the time of factory shipment or the like, and obtain a value obtained by actually measuring the moment of inertia in the posture. You may make it memorize | store. If the moment of inertia is actually measured and stored in the same posture as that at the time of detection, not only the calculation of a complicated design value of the moment of inertia becomes unnecessary, but also the influence of a design error can be reduced at the same time.

  The viscous friction coefficient D may vary depending on the temperature, particularly due to the properties of grease applied to the rotating shaft of the motor. For this reason, the robot 1 corrects the viscous friction coefficient D when detecting the moment of inertia according to the temperatures detected by the wheel temperature detection unit 115, the upper arm temperature detection unit 125, and the forearm temperature detection unit 135. Thereby, the moment of inertia can be detected with higher accuracy. Of course, such correction can be omitted if grease having a small temperature dependency is used. In addition, if an inertia moment detection that is less dependent on temperature is used, the wheel temperature detection unit 115, the upper arm temperature detection unit 125, and the forearm temperature detection unit 135 can be omitted.

  Further, although the moment of inertia is detected in the order of the housing 200, the upper arm 202, and the forearm 203, it may be detected in the reverse order.

  Further, when detecting the moment of inertia of the robot 1, the posture for minimizing the moment of inertia at the joint may be such that the upper arm and the forearm are folded, or the upper arm and the forearm can be expanded and contracted. May be.

  As described above, according to the present invention, it is possible to detect the presence or absence of a foreign substance attached to an arbitrary part without using a special sensor.

  According to the present invention, it is possible to detect the presence or absence of a foreign object such as a wiretap or a voyeur attached to an arbitrary part, which is useful for a foreign object detection method and a robot.

The block diagram which shows the structure of the robot in embodiment of this invention Block diagram showing the configuration of the foreign matter detection unit Flow chart for explaining foreign object detection operation in the robot (A) Explanatory drawing explaining the posture of the robot when detecting foreign matter on the wheel (b) Explanatory drawing explaining the posture of the robot when detecting foreign matter on the upper arm (c) The posture of the robot when detecting the foreign matter on the forearm Explanatory drawing to explain

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot 10 Wheel foreign object detection part 20 Upper arm foreign object detection part 30 Forearm foreign object detection part 100 Foreign object detection control part 110 Wheel drive part 111 Wheel motor 112 Wheel angular velocity detection part 113 Wheel detection part 114 Wheel judgment part 115 Wheel temperature detection part 120 Upper arm drive Unit 121 Upper arm motor 122 Upper arm angular velocity detection unit 123 Upper arm detection unit 124 Upper arm determination unit 125 Upper arm temperature detection unit 130 Forearm drive unit 131 Forearm motor 132 Forearm angular velocity detection unit 133 Forearm detection unit 134 Forearm determination unit 135 Forearm temperature detection unit 140 Foreign body treatment Part 150 Movement control part 160 Hand control part 200 Case 201 Wheel 202 Upper arm 203 Forearm 204 Hand 210 Wheel stopper 300, 301, 302, 303 Joint

Claims (13)

A drive unit that rotates at least one of the plurality of members around a joint connecting the plurality of members;
A control unit that outputs a control signal for rotating the member with respect to the drive unit;
A detection unit for detecting a first moment of inertia around the rotation axis at the joint;
The value of the first moment of inertia is compared with the value of the second moment of inertia around the rotation axis at the joint when no foreign matter is attached, and the foreign matter attached to at least one of the plurality of members. A foreign matter judgment unit for judging the presence or absence of
A robot characterized by comprising: The foreign object determining unit determines that a foreign object is attached when the value of the first moment of inertia is larger than the value of the second moment of inertia. robot. A plurality of the joints;
The detection unit sequentially detects the first moment of inertia around the rotation axis at each of the plurality of joints,
The foreign matter determination unit determines whether or not foreign matter is attached to each of the first inertia moment values detected for each joint, and the foreign matter is attached based on the determined determination results. The robot according to claim 1 or 2, wherein a member is specified. The robot according to claim 3, wherein the control unit holds a driving unit related to a joint that does not detect the first moment of inertia in a predetermined posture. The control unit outputs a control signal for performing a predetermined rotation to the drive unit related to the joint that detects the first moment of inertia, and outputs the control signal to the joint that does not detect the first moment of inertia. Control for causing the driving unit to take a posture for minimizing the first moment of inertia around the rotation axis in the driving unit related to the joint that detects the first moment of inertia as the predetermined posture. The robot according to claim 4, wherein the robot outputs a signal. The robot according to any one of claims 3 to 5, wherein the control unit holds a member that does not detect the first moment of inertia in a stationary state. A member fixing portion for holding at least any one of the plurality of members not detecting the first moment of inertia;
The robot according to claim 6, wherein the detection unit detects the first moment of inertia after at least one of the plurality of members is held stationary by the member fixing unit. . 8. The robot according to claim 3, further comprising a foreign substance treatment unit that removes the foreign substance from a member that is identified as having a foreign substance attached by the foreign substance determination unit. 9. . The detection unit detects the first moment of inertia J,
T = J × α + D × ω
(T: torque, α: rotational angular acceleration, D: viscous friction coefficient, ω: rotational angular velocity)
The robot according to any one of claims 1 to 8, wherein the detection is performed based on the relational expression. A temperature detection unit for detecting the temperature of the joint;
The detection unit corrects the torque T or the viscous friction coefficient D in the relational expression based on the temperature detected by the temperature detection unit, and detects the first moment of inertia J. The robot according to claim 9. In a foreign object detection method using a robot comprising a plurality of members, a joint connecting the plurality of members, and a drive unit that rotates at least one member of the plurality of members around the joint,
A driving step of rotating at least one member of the plurality of members around the joint by the driving unit;
A control step of outputting a control signal for rotating the member with respect to the drive unit;
A detection step of detecting a first moment of inertia around the rotation axis at the joint;
The value of the first moment of inertia is compared with the value of the second moment of inertia around the rotation axis at the joint when no foreign matter is attached, and the foreign matter attached to at least one of the plurality of members. A foreign matter judgment step for judging the presence or absence of
A foreign object detection method comprising: 12. The foreign matter determining step determines that a foreign matter is attached when the value of the first moment of inertia is greater than the value of the second moment of inertia. Foreign object detection method. A plurality of the joints;
The detecting step sequentially detects the first moment of inertia around the rotation axis at each of the plurality of joints,
In the foreign matter determining step, the presence or absence of foreign matter is determined for each value of the first moment of inertia detected for each joint, and the foreign matter is attached based on a plurality of determined determination results. The foreign object detection method according to claim 11, wherein a member is specified.

Images