Patent Publication Number: US-11040446-B2

Title: Transporter, transport system, and controller

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2018-046924 filed on Mar. 14, 2018, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a transporter, a transport system, and a controller. 
     BACKGROUND 
     Transporters for holding and moving an object are known. 
     A transporter is expected to move an object more efficiently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically showing a transport system according to a first embodiment; 
         FIG. 2  is a block diagram showing a system configuration of a transporter according to the first embodiment; 
         FIG. 3  is a front view showing a first example of a test operation of the transporter according to the first embodiment: 
         FIG. 4  is a front view showing a second example of the test operation of the transporter according to the first embodiment; 
         FIG. 5A  is a perspective view showing one example of a movement plan of an object which is used by the transporter according to the first embodiment; 
         FIG. 5B  is a perspective view showing a third example of the test operation of the transporter according to the first embodiment: 
         FIG. 6  is a front view showing one example of score calculation executed by a holding state determiner according to the first embodiment; 
         FIG. 7  is a diagram showing another example of score calculation executed by a holding state determiner according to the first embodiment; 
         FIG. 8  is a perspective view showing a first modification example of the movement plan according to the first embodiment; 
         FIG. 9  is a perspective view showing a second modification example of the movement plan according to the first embodiment; 
         FIG. 10A  is a perspective view showing a characteristic of a coefficient α relating to a posture of a holder according to the first embodiment; 
         FIG. 10B  is a perspective view showing a third modification example of the movement plan according to the first embodiment; 
         FIG. 11  is a flowchart showing one example of a flow of a process of a control device according to the first embodiment; 
         FIG. 12  is a block diagram showing a system configuration of a transporter according to a second embodiment; 
         FIG. 13  is a front view showing a first example of a test operation of the transporter according to the second embodiment; 
         FIG. 14  is a front view showing a second example of the test operation of the transporter according to the second embodiment; 
         FIG. 15  is a front view showing a holder according to a modification example of the second embodiment; and 
         FIG. 16  is a diagram schematically showing a transport system according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to one embodiment, a transporter includes a holder, a moving mechanism, a sensor, an operation controller, and a parameter estimator. The holder is configured to hold an object. The moving mechanism is configured to move the holder. The sensor is provided at the holder or the moving mechanism. The operation controller is configured to execute a test operation of moving the holder in a state in which the object is held by the holder. The parameter estimator is configured to estimate at least one parameter relating to the object based on a result of detection acquired by the sensor during the test operation. 
     Hereinafter, a transporter, a transport system, a controller, and a transport method according to embodiments will be described with reference to the drawings. In the description presented below, the same reference numerals will be attached to components having the same or similar functions. Duplicate description of these components may be omitted. In the specification, the term “based on XX” represents “based at least on XX” and includes the case of being based on any other element in addition to XX. In addition, the term “based on XX” is not limited to “based directly on XX”, but also represents “based on something that is acquired by an arithmetic operation or other process being performed on XX”. Here, “XX” is an arbitrary element (for example, arbitrary information). 
     First Embodiment 
     A first embodiment will be described with reference to  FIGS. 1 to 11 . FIG. is a diagram schematically showing a transport system  1  according to the first embodiment. In this embodiment, the transport system  1 , for example, is a handling system used for distribution. The transport system  1  moves an object (transport target object) O positioned at a movement source S 1  to a movement destination S 2 . Each of the movement source S 1  and the movement destination S 2 , for example, is a box pallet, a carriage, tote, a foldable container, various conveyers, a sorter, or the like but there is no limitation thereto. In addition, the transport system  1  is not limited to a handling system for distribution and can be broadly applied to an industrial robot system used in a factory, other systems, and the like. “Transporter.” “transport system,” and “transport method” described here are not limited to an apparatus, a system, and a method mainly used for conveying an object and also include an apparatus, a system, and a method accompanying conveyance (movement) of an object for product assembly or a part of another object. 
     First, the entire configuration of the transport system  1  will be described. 
     As illustrated in  FIG. 1 , the transport system  1 , for example, includes a transporter  11  and a management device  12 . 
     The transporter  11 , for example, is a robot device and holds an object O positioned at the movement source S 1  and moves the held object O to the movement destination S 2 . The transporter  11  can communicate with the management device  12  using wires or wirelessly. Details of the transporter  11  will be described later. 
     The management device (for example, host control apparatus)  12  manages and controls the entire transport system  1 . For example, the management device  12  includes an input receiver that receives an operator&#39;s direction for the transporter  11  and an information outputter that displays an operation state of the transporter  11  for an operator. The management device  12  controls the transporter  11  based on a direction input to the input receiver. In addition, the management device  12  may be a device only performing information processing such as a server device without including the input receiver and the information outputter. 
     Next, one example of the transporter  11  will be described. 
     As illustrated in  FIG. 1 , the transporter  11 , for example, includes a holder  100 , a moving mechanism  200 , an object detecting camera  300 , a measurer  400 , and a control device  500 . 
     The holder  100  is a holding device that holds an object O positioned at the movement source S 1 . For example, the holder  100  includes a suction device such as a vacuum pump and a sucker (for example, a suction pad) communicating with the suction device and holds an object O by suction. Here, the holder  100  may be a holder holding an object O by pinching the object O using a plurality of pinching members or a holder holding an object O using any other mechanism. In several diagrams including  FIG. 1 , the holder  100  is schematically illustrated. 
     The moving mechanism  200  is a mechanism that moves the holder  100  to a desired position. For example, the moving mechanism  200  may be a robot arm of six axes and including a plurality of arm members  201 , a plurality of rotators  202  connecting the plurality of arm members  201  such that they become rotatable, and actuators (for example, motors), which are not illustrated in the drawing, driving the rotators  202 . Here, the moving mechanism  200  may be an orthogonal robot arm of three axes or a mechanism that moves the holder  100  to a desired position by employing any other configuration. For example, the moving mechanism  200  may be a flying body (for example, drone) that lifts and moves the holder  100  using rotor blades. 
     The object detecting camera  300  images an object O (a holding target) positioned at the movement source S 1 . For example, the object detecting camera  300  is provided at the holder  100  or the moving mechanism  200 . Here, the object detecting camera  300  may be fixed to a position on the lateral side of the movement source S 1  or above the movement source S 1 , or the like and image an object O positioned at the movement source S 1 . 
     Here, in this embodiment, there are cases in which a plurality of types of object O having different sizes or shapes are randomly placed at the movement source S 1 . The object detecting camera  300  is one example of a detector that acquires information used for determining a type of an object O to be held. The object detecting camera  300 , for example, may acquire image data of an outer shape of an object O or acquire image data of a feature portion of an object O. The “feature portion of an object” may be a portion of an object O that includes a unique shape according to the type of object O, a tag (text information, a barcode, or the like used for identifying an object) attached to an object O, or the like. The object detecting camera  300  outputs captured image data to the control device  500 . 
     The measurer  400  includes one or more sensors and measures one or more physical quantities acting on an object O. In this embodiment, the measurer  400  includes a force sensor  401  and a holding force detecting sensor  402 . 
     The force sensor  401  is provided at the holder  100  or the moving mechanism  200 . The force sensor  401  is one example of a “sensor.” By measuring a force and moment acting on the holder  100  holding the object O, the force sensor  401  measures the weight of the object O held by the holder  100  and measures a force and moment acting on the object O in a test operation to be described later. For example, the force sensor  401  may be a force sensor of six axes and measures accelerations of three axes in an orthogonal coordinate system and three moments around the three axes. The force sensor  401  outputs the measured information to the control device  500 . 
     The holding force detecting sensor  402 , for example, is provided at the holder  100  and measures a value relating to a holding force of the holder  100  for the object O. The holding force detecting sensor  402  is one example of a “detector.” For example, in a case where the holder  100  including a sucker is used, the holding force detecting sensor  402  is a pressures sensor capable of detecting a pressure value inside the sucker. The pressure sensor measures a pressure value inside the sucker as a value relating to a holding force of the holder  100  for the object O. On the other hand, in a case where the holder  100  including a pinching member is used, the holding force detecting sensor  402  is a pressure sensitive sensor (for example, a piezo-device) provided at the pinching member. The pressure sensitive sensor measures a contact pressure between the pinching member and the object O as a value relating to the holding force of the holder  100  for the object O. The holding force detecting sensor  402  outputs the measured information to the control device  500 . 
     The control device  500  controls the overall operation of the transporter  11 . The control device  500  is one example of a “controller.”  FIG. 2  is a block diagram showing a system configuration of the transporter  11 . The control device  500  includes, for example, an information acquirer  510 , an image analyzer  520 , an object determiner  530 , a planner  540 , an operation controller  550 , and a storage  560 . 
     A part or the whole of each functional unit (for example, the information acquirer  510 , the image analyzer  520 , the object determiner  530 , the planner  540 , and the operation controller  550 ) of the control device  500 , for example, is realized by one or more processors such as a central processing unit (CPU) or a graphics processing unit (GPU) executing a program stored in a program memory. However, a part or the whole of the functional unit may be realized by hardware (for example, circuitry) such as a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a programmable logic device (PLD). In addition, the storage  560  is realized by a flash memory, an electrically erasable programmable read-only memory (EEPROM), a read-only memory (ROM), a random access memory (RAM), or the like. 
     Here, for the convenience of description, the storage  560  will be described first. The storage  560  stores an object database  561  (hereinafter, referred to as an “object DB  561 ”). In the object DB  561 , for example, types of one or more objects O, feature information of the objects O, and various parameters relating to the objects O are registered in association with each other. An object O registered in the object DB may be an object O that was transported by the transporter  11  in the past or an object O that is registered in advance by the management device  12 . The “feature information” is information that can be used for specifying the object O (identifying the object from other objects) and is an external shape (a size or a shape) or a color of the object O or information represented in a tag attached to the object O. The “parameters relating to an object” are values representing the physical properties of the object O and are a weight of the object O, a three-dimensional position of the center of gravity of the object O, and a friction coefficient of the surface of the object O, and the like. 
     The information acquirer  510  acquires image data captured by the object detecting camera  30  from the object detecting camera  300 . In addition, the information acquirer  510  acquires information measured by the measurer  400  from the measurer  400 . “Acquisition” described here is not limited to a case in which information is acquired by transmitting a transmission request signal and includes a case in which information is acquired by passively receiving the information. The information acquirer  510  outputs the image data acquired from the object detecting camera  300  to the image analyzer  520 . In addition, the information acquirer  510  outputs the information acquired from the measurer  400  to the planner  540 . 
     The image analyzer  520  performs a predetermined image analysis for the image data acquired by the object detecting camera  300  and recognizes position information, external shape information, and feature information of the object O. The image analyzer  520  outputs the position information and the external shape information of the object O acquired through the image analysis to the planner  540 . In addition, the image analyzer  520  outputs the feature information of the object O acquired through the image analysis to the object determiner  530 . 
     The object determiner  530  compares the feature information acquired by the image analyzer  520  with feature information registered in the object DB  561  of the storage  560 . Accordingly, the object determiner  530  determines whether the object O to be held is a known object or an unknown object for the transporter  11 . A “known object” represents an object for which parameters relating to the object O are registered in the object DB  561 . On the other hand, an “unknown object” represents an object for which parameters relating to the object O are not registered in the object DB  561 . 
     For example, in a case where a difference between the feature information acquired by the image analyzer  520  and the feature information registered in the object DB  561  is less than a threshold, the object determiner  530  determines that the object O to be held is a known object. On the other hand, in a case where the difference between the feature information acquired by the image analyzer  520  and the feature information registered in the object DB  561  is the threshold or more, the object determiner  530  determines that the object O to be held is an unknown object. The object determiner  530  outputs a result of the determination by the object determiner  530  to the planner  540 . 
     The planner  540  generates a movement plan for moving the object O from the movement source S 1  to the movement destination S 2 . In this embodiment, by performing a test operation, the planner  540  generates a movement plan for moving the object O more efficiently and more assuredly. The planner  540 , for example, includes a holding operation generator  541 , a movement plan generator  542 , a test operation generator  543 , a parameter estimator  544 , a holding state determiner  545 , a movement plan modifier  546 , and a hold retry operation generator  547 . 
     First, the holding operation generator  541  will be described. The holding operation generator  541  generates a holding operation plan for holding the object O based on the position and the features (the size, the shape, and the like) of the object O. For example, the holding operation plan includes a holding position on the surface of the object O held by the holder  100 , a holding posture of the holder  100  with respect to the object O, and the like. The holding operation generator  541  outputs the generated holding operation plan to the operation controller  550 . 
     Next, the movement plan generator  542  will be described. The movement plan generator  542  generates a movement plan for moving the object O held at the movement source S 1  to the movement destination S 2  based on the features (the size, the shape, and the like) of the object O, obstacles between the movement source S and the movement destination S 2 , other restriction conditions, and the like. The movement plan, for example, includes a movement path (track) of the holder  100 , a speed of the holder  100 , an acceleration of the holder  100 , and the like for moving the object O. In this embodiment, the movement plan generator  542  generates a movement plan for the transporter  11  to move the object O from the movement source S 1  to the movement destination S 2  in a possible shortest time. In other words, the movement plan generator  542  generates a movement plan that satisfies a predetermined condition for efficiently moving the object O. 
     Next, the test operation generator  543  will be described. In a case where an object O to be held is an unknown object, the test operation generator  543  generates an operation plan for performing a test operation for estimating the parameters of the object O. The test operation is performed by moving the holder  100  in a state in which the object O is held by the holder  100 . Here, “moving the holder  100 ” represents changing at least one of the position and the posture of the holder  100  and, for example, is realized by controlling the moving mechanism  200 . This test operation is performed before a transport operation of moving the object O toward the movement destination S 2 . For example, a test operation is arbitrarily selected from among several test operations represented below or may be performed by combining the test operations. 
     First Example of Test Operation 
     First, a first example of a test operation will be described.  FIG. 3  is a front view showing the first example of the test operation performed by the transporter  11 . Here, in a case where the holder  100  is directed toward the vertical direction, while a position of the center of gravity of the object O in a position in the horizontal direction can be calculated based on a result of the measurement acquired by the force sensor  401  of six axes, a position in the vertical direction cannot be acquired. Thus, the test operation of this first example includes an operation of inclining the holder  100  holding the object O by rotating the rotator  202  of the moving mechanism  200  by the operation controller  550 . Accordingly the position of the center of gravity of the object O with respect to the holder  100  changes in the horizontal direction and the vertical direction, and a force and a moment measured by the force sensor  401  change. In other words, by comparing forces and moments measured by the force sensor  401  in a state before the inclination of the object O and in a state in which the object O is inclined, a three-dimensional position (a position in the horizontal direction and a position in the vertical direction) of the center of gravity of the object O can be calculated. For example, this test operation includes temporarily stopping the holder  100  and the object O in a state in which the holder  100  holding the object O is inclined. For example, the force sensor  401  measures a force and a moment acting on the holder  100  holding the object O in a state in which the object O is stopped before the holder  100  is inclined (or after returning to the original state from the inclined state), and measures a force and a moment acting on the holder  100  holding the object O in a state in which the holder  100  is inclined and the object O is stopped. For example, the test operation of this first example is performed at a position at which the holder  100  has lifted the object O from the movement source S 1  without moving the holder  100  toward the movement destination S 2 . 
     In the test operation of this first example, static measurement can be performed using the force sensor  401  in a state in which the object O is stopped, and accordingly, there are cases in which parameters relating to the objects O can be estimated with higher accuracy than that in a test operation of a second example to be described later. For this reason, for example, in a case where the features of the object O satisfy a predetermined condition (for example, a case in which there is sufficient space for inclining the object O) in a case where the test operation generator  543  generates a test operation, the test operation of the first example may be executed with a higher priority with respect to the test operation of the second example. 
     Second Example of Test Operation 
     Next, the second example of the test operation will be described.  FIG. 4  is a front view showing the second example of the test operation performed by the transporter  11 . In this second example, the test operation includes an operation of applying an acceleration (translational acceleration) to the holder  100  holding an object O without inclining the holder  100 . Accordingly, a force and a moment measured by the force sensor  401  change. In other words, by measuring an inertial force and an inertial moment acting on the object O in a case where a translational acceleration is applied to the holder  100 , a three-dimensional position of the center of gravity of the object O can be calculated. For example, the test operation of this second example may be performed by moving the object O in a direction different from a direction toward the movement destination S 2 . 
     In the test operation of this second example, a space for inclining the object O is not necessary. For this reason, for example, in a case where there is not sufficient space for inclining an object O, the test operation generator  543  may execute the test operation of the second example with a higher priority with respect to the test operation of the first example. In addition, in this second example, measurement can be performed while moving the object O, and accordingly, there is a possibility that a transition to a next operation may be able to be made directly. For this reason, in a case where shortening of an operation time needs to be prioritized over accuracy of the estimation of parameters relating to the object O, the test operation of the second example may be executed with a higher priority with respect to the test operation of the first example. 
     Third Example of Test Operation 
     Next, a third example of the test operation will be described. Here,  FIG. 5A  is a perspective view showing one example of a movement plan generated by the movement plan generator  542 . In this movement plan, a first acceleration a 1  that is a maximum acceleration in a first direction is assumed to act on the object O at a first time point (for example, an initial stage of movement), and a second acceleration a 2  that is a maximum acceleration in a second direction is assumed to act thereon at a second time point (for example, a final stage of movement). For example, the first acceleration a 1  is an acceleration for accelerating the object O toward the movement destination S 2 . For example, the second acceleration a 2  is an acceleration for stopping (in other words, decelerating) the object O at the movement destination S 2 . 
       FIG. 5B  is a perspective view showing a third example of a test operation performed by the transporter  11 . The test operation of this third example is performed by applying one or more maximum accelerations assumed in a movement plan generated by the movement plan generator  542  to the object O. For example, in the test operation corresponding to the movement plan illustrated in  FIG. 5A , an operation of applying a first acceleration a 1  to the object O in the first direction and applying a second acceleration a 2  to the object O in the second direction is included. This test operation, for example, is performed at a position to which the object O is lifted from the movement source S 1  without moving the object O as in the movement plan. 
     Next, applied examples of the first example to the third example of the test operation will be described. For example, the test operation generator  543  may change a content of the test operation based on a weight of an object O measured by the force sensor  401 . For example, in a case where a weight of the object O is more than a first weight threshold, the test operation generator  543  performs the test operation at a lower acceleration than that in a case where the weight of the object O is the first weight threshold or less. Accordingly, the test operation can be performed in a state in which it is more difficult for the object O to be dropped. On the other hand, in a case where a weight of the object O is a second weight threshold or less, the test operation generator  543  performs the test operation at a higher acceleration than that in a case where the weight of the object O is the second weight threshold or more. Accordingly, a time required for the test operation can be shortened. Here, the first weight threshold and the second weight threshold may have the same value. 
     Next, the parameter estimator  544  will be described. The parameter estimator  544  estimates parameters relating to the object O based on one or more physical quantity acting on the object O in accordance with the test operation described above (in other words, one or more physical quantities acting on the holder  100  in accordance with the test operation). In this embodiment, in a case where an object O to be held is determined as being a known object by the object determiner  530  (in other words, a case in which an object O of which parameters are registered in the object DB  561  is determined, and the test operation is not performed), the parameter estimator  544  does not estimate the parameters relating to the object O. On the other hand, in a case where an object O to be held is determined as being an unknown object by the object determiner  530  (in other words, in a case where an object O of which parameters are not registered in the object DB  561  is determined, and the test operation is performed), the parameter estimator  544  estimates the parameters relating to the object O. 
     Hereinafter, the estimation of parameters by the parameter estimator  544  will be described. These parameters are estimated, for example, based on a force and a moment that act on the holder  100  and are measured by the force sensor  401 . In this embodiment, as the parameters relating to an object O, the parameter estimator  544  estimates a weight of the object O and a three-dimensional position of the center of gravity of the object O. 
     For example, the parameter estimator  544  estimates the weight of the object O based on a force acting on the holder  100  in a state in which the object O is held and lifted by the holder  100 . 
     In addition, in a case where the test operation of the first example is performed, the parameter estimator  544  estimates a three-dimensional position of the center of gravity of the object O based on relational equations among the posture of the holder  100  that is, before the test operation (before inclining the object O) and a force and a moment acting on the holder  100  in that posture, and the posture of the holder  100  during the test operation (that is, a state in which the object O is inclined), and between a force and a moment acting on the holder  100  in that posture. Here, the posture of the holder  100 , for example, can be acquired based on a detection value output from a detector (an encoder or the like) provided at the moving mechanism  200  or a control target value output from the operation controller  550  or the like. 
     In addition, in a case where the test operation of the second example or the third example described above is performed, the parameter estimator  544  estimates a three-dimensional position of the center of gravity of the object O based on an inertial force and an inertial moment acting on the holder  100  during the test operation. 
     Next, the holding state determiner  545  will be described. The holding state determiner  545  determines a holding state of the object O using the holder  100  (that is, a holding state of the holder  100  for the object O) based on a value relating to a holding force detected by the holding force detecting sensor  402  and parameters (for example, a weight and a three-dimensional position of the center of gravity) relating to the object O. In this embodiment, the holding state determiner  545  determines a holding state of the object O using the holder  100  based on a movement plan of the object O for movement toward the movement destination S 2  of the object O (for example, a movement plan generated by the movement plan generator  542 ) in addition to the value relating to the holding force detected by the holding force detecting sensor  402  and the parameters relating to the object O. 
     Here, in a case where the object O is a known object, the holding state determiner  545  determines a holding state of the object O using the parameters relating to the object O registered in the object DB  561 . On the other hand, in a case where the object O is an unknown object, the holding state determiner  545  determines a holding state of the object O using the parameters relating to the object O estimated by the parameter estimator  544 . 
     In this embodiment, the holding state determiner  545  calculates the holding state of the object O using the holder  100  as a score.  FIG. 6  is a front view showing one example of score calculation using the holding state determiner  545 .  FIG. 6  shows a case in which an object O is held by a sucker  101  of the holder  100 . Here, in a case where a mass of the object O is denoted by m, an assumed acceleration acting on the object O is denoted by “a” (three-dimensional vector), a gravitational acceleration acting on the object O is denoted by g (three-dimensional vector), a resultant force based on the assumed acceleration a and the gravitational acceleration g (a translational force applied to the sucker  101 ) is denoted by F (three-dimensional vector), a cross-sectional area of a cross-section of the sucker  101  taken along a direction that is substantially orthogonal to a direction in which the sucker  101  and the object O overlap with each other (hereinafter, referred to as a “specific cross-section”) is denoted by A, a radius of the sucker  101  on the specific cross-section is denoted by r, a difference between the atmospheric pressure and the pressure of the inside of the sucker  101  is denoted by ΔP, a position vector of a three-dimensional position of the center of gravity of the object O is denoted by c (three-dimensional vector), a moment applied to the sucker  101  is denoted by T (scalar), a coefficient relating to the posture of the holder  100  (sucker  101 ) with respect to the direction of the resultant force F is denoted by α, and a coefficient relating to the moment is denoted by β 1 , the holding state determiner  545  calculates a score S representing a holding state of the object O based on the following Equation (1). 
     
       
         
           
             
               
                 
                   
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     Here, the mass m of the object is calculated based on a result of measurement using the force sensor  401 . The assumed acceleration “a” acting on the object O is a maximum acceleration assumed to applied to the object O in the movement plan of the object O for movement toward the movement destination S 2  and, for example, can be acquired from the movement plan generated by the movement plan generator  542 . The pressure difference ΔP, for example, is calculated based on a pressure value of the inside of the sucker  101  that is measured by the holding force detecting sensor  402  that is a pressure sensor. The position vector c of the three-dimensional position of the center of gravity of the object O is a position vector representing a three-dimensional position of the center of gravity of the object O using the center of the sucker  101  on the specific cross-section as a base point and uses a three-dimensional position of the center of gravity estimated by the parameter estimator  544  in a case where the object O is unknown and uses a three-dimensional position of the center of gravity registered in the object DB  561  in a case where the object O is known. 
     The coefficient α relating to the posture of the holder  100  with respect to the direction of the resultant force F is a coefficient that changes in accordance with a relation between a direction in which the resultant force F based on the assumed acceleration “a” and the gravitational acceleration g acts and the posture of the holder  100 . For example, the coefficient α is a minimum in a case where a direction in which the sucker  101  and the object O are aligned and a direction in which the resultant force F acts coincide with each other, increases as an angle between the direction in which the sucker  101  and the object O are aligned and the direction in which the resultant force F acts increases, and is a maximum in a case where the direction in which the sucker  101  and the object O are aligned and the direction in which the resultant force F acts are substantially orthogonal to each other. This coefficient α is set in accordance with the features (a shape, a material, and the like) of the holder  100 . 
     The coefficient β 1  relating to a moment is a value in which the degree of easiness, in which the holding force of the sucker  101  is damaged in accordance with the moment, is reflected and is set in accordance with the material, the shape, and the like of the sucker  101 . The coefficient β 1  relating to a moment has a smaller value in a case where the holding force of the sucker  101  is more easily maintained in a case where the moment acts. 
       FIG. 7  is a diagram showing another example of score calculation executed by the holding state determiner  545 .  FIG. 7  shows a case in which an object O is pinched and held by one pair of pinching members  102  of the holder  100 . Here, in a case where a mass of the object O is denoted by m, an assumed acceleration acting on the object O is denoted by “a” (three-dimensional vector), a gravitational acceleration acting on the object O is denoted by g (three-dimensional vector), a resultant force based on the assumed acceleration “a” and the gravitational acceleration g (a translational force applied to the pinching members  102 ) is denoted by F (three-dimensional vector), a gripping force acting on the object O from one of the pinching members  102  is denoted by H, a half of the width of the pinching members  102  in a direction that is substantially orthogonal to a direction in which the object O is interposed between the one pair of the pinching members  102  is denoted by r, a position vector of a three-dimensional position of the center of gravity of the object O is denoted by c (three-dimensional vector), a moment applied to the pinching members  102  is denoted by T (scalar), a coefficient relating to the posture of the holder  100  (the pinching members  102 ) with respect to the direction of the resultant force F is denoted by a, and a coefficient relating to friction is denoted by β 2 , the holding state determiner  545  calculates a score S representing a holding state of the object O based on the following Equation (2). 
     
       
         
           
             
               
                 
                   
                     S 
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                           ( 
                           
                             F 
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                               ( 
                               
                                 T 
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                                 r 
                               
                               ) 
                             
                           
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                       m 
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                   ⁢ 
                   
                     T 
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     Here, meanings and calculation methods of the mass m of the object, the assumed acceleration “a” acting on the object O. and the position vector c of the three-dimensional position of the center of gravity of the object O are almost the same as those of a case illustrated in  FIG. 6 . The gripping force H is calculated based on a contact pressure between the pinching member  102  and the object O measured by the holding force detecting sensor  402  that is a pressure sensitive sensor and a contact area between the pinching member  102  and the object O. The coefficient α relating to the posture of the holder  100  with respect to the direction of the resultant force F is a coefficient that changes in accordance with a relation between a direction in which the resultant force F based on the assumed acceleration “a” and the gravitational acceleration g acts and the posture of the pinching members  102 . The coefficient β 2  relating to friction is a coefficient that is set using a frictional coefficient of the surface of the pinching member  102 . For example, the coefficient β 2  has a larger value in a case where the frictional coefficient of the surface of the pinching member  102  is larger. 
     The holding state determiner  545  determines a holding state of the object O based on the score S calculated using the model illustrated in  FIG. 6  or  FIG. 7 . For example, in a case where the score S is a first threshold K 1  or more (one example of a case in which a first condition is satisfied), the holding state determiner  545  determines that there is no problem in moving the object O using the holder  100  based on the movement plan (a movement plan of the initial period; a movement plan without any modification) generated by the movement plan generator  542 . On the other hand, in a case where the score S is less than the first threshold K 1  and is a second threshold K 2  or more (one example of a case in which a second condition is satisfied), the holding state determiner  545  determines that there is no problem in moving the object O using the holder  100  in a case where the movement plan is modified. In a case where the score S is less than the second threshold K 2  (one example of a case in which a third condition is satisfied), the holding state determiner  545  determines that it is necessary to release the holding of the object O by the holder  100  temporarily and re-hold the object O using the holder  100 . 
     Next, the movement plan modifier  546  will be described. In a case where the score S calculated by the holding state determiner  545  is less than the first threshold K 1  and is the second threshold K 2  or more, the movement plan modifier  546  modifies the movement plan of the object O. The movement plan modifier  546 , for example, modifies the movement plan based on the value relating to the holding force detected by the holding force detecting sensor  402  and the parameters relating to the object O estimated by the parameter estimator  544  or the parameters acquired from the object DB  561 . In addition, first to third modification examples of the movement plan represented below may be combined and performed together. 
     First, the first modification example of the movement plan will be described.  FIG. 8  is a diagram showing the first modification example of the movement plan. The movement plan modifier  546 , for example, modifies the movement plan such that the movement path (track) of the object O is not changed, and the maximum acceleration acting on the object O is decreased. For example, in a case where high maximum accelerations a 11  and a 21  act on the object O in an initial stage and a final stage of movement, respectively, in a movement plan before modification, the movement plan modifier  546  modifies the movement plan such that the maximum accelerations acting on the object O are decreased in the initial stage and the final stage of the movement (accelerations a 12  and a 22  lower than the maximum accelerations a 11  and a 21 , respectively, act as maximum accelerations). In redetermination (redetermination based on the modified movement plan) using the holding state determiner  545 , the movement plan modifier  546  modifies the movement plan such that the score S becomes the first threshold K 1  or more. 
     Next, the second modification example of the movement plan will be described.  FIG. 9  is a diagram showing the second modification example of the movement plan. For example, by changing the movement path (track) of the object O, the movement plan modifier  546  modifies the movement plan such that the maximum acceleration acting on the object O is decreased. Here, a track t 1  included in the movement plan before modification may include a part in which the track is abruptly bent in the vicinity of an obstacle H for shortening the movement path of the object O while avoiding the obstacle H. In such a case, in the part in which the track t 1  is abruptly bent, a high acceleration (a maximum acceleration a 31 ) acts on the object O. In such a case, the movement plan modifier  546  modifies the movement plan such that the object O is moved along a track t 2  in which an abrupt direction change is suppressed by gently moving the object O by making a slight detour around an obstacle H, and the maximum acceleration acting on the object O is decreased (an acceleration a 32  lower than the maximum acceleration a 31  acts as a maximum acceleration). In redetermination (redetermination based on a modified movement plan) using the holding state determiner  545 , the movement plan modifier  546  modifies the movement plan such that the score S is the first threshold K 1  or more. 
     Next, the third modification example of a movement plan will be described.  FIG. 10A  is a diagram showing a characteristic of a coefficient α relating to the posture of the holder  100  with respect to the direction of the resultant force F. A length of an arrow illustrated in  FIG. 10A  represents the magnitude of the coefficient α of a case in which the resultant force F acts in the direction of the arrow. As described above, the coefficient α is a minimum in a case where a specific direction set in accordance with a positional relation between the holder  100  and the object O (for example, a direction in which the sucker  101  and the object O are aligned) and a direction in which the resultant force F acts coincide with each other, increases as an angle between the specific direction and the direction in which the resultant force F acts increases, and is a maximum in a case where the specific direction and the direction in which the resultant force F acts are substantially orthogonal to each other. 
       FIG. 10B  is a diagram showing the third modification example of a movement plan. The movement plan modifier  546 , for example, modifies the movement plan of the object O such that the posture of the holder  100  is changed during movement of the object O toward the movement destination S 2 . For example, the movement plan modifier  546  changes the posture of the holder  100  during the movement such that the direction in which the resultant force F acts is close to a direction in which the coefficient α decreases the most. The movement plan modifier  546  modifies the movement plan such that the score S becomes the first threshold K 1  or more in redetermination using the holding state determiner  545  (redetermination based on the modified movement plan). 
     Next, the hold retry operation generator  547  will be described. In a case where the score S calculated by the holding state determiner  545  is less than the second threshold K 2 , the hold retry operation generator  547  generates an operation plan for retrying (re-performing) a holding operation of the object O. In other words, the hold retry operation generator  547  generates an operation plan in which the object O is released at the movement source S 1  temporarily, and the object O is re-held by the holder  100 . For example, the hold retry operation generator  547  generates a hold retry operation plan in which at least one of a holding position on the surface of the object O at which the holder  100  holds the object O and a holding posture of the holder  100  with respect to the object O is changed. The hold retry operation generator  547  outputs the generated hold retry operation plan to the operation controller  550 . 
     Next, the operation controller  550  will be described. The operation controller  550  controls the holder  100  and the moving mechanism  200  based on the operation plan planned by the planner  540 . For example, the operation controller  550  holds an object O positioned at the movement source S by controlling the holder  100  and the moving mechanism  200  based on a holding operation plan generated by the holding operation generator  541 . The operation controller  550  executes a test operation of moving the object O using the holder  100  by controlling the moving mechanism  200  based on an operation plan of the test operation generated by the test operation generator  543 . In a case where the score S calculated by the holding state determiner  545  is the first threshold K 1  or more, the operation controller  550  moves the object O using the holder  100  based on a movement plan (a movement plan of an initial period; a movement plan without any modification) of the object O generated by the movement plan generator  542 . On the other hand, in a case where the score S calculated by the holding state determiner  545  is less than the first threshold K 1  and is the second threshold K 2  or more, the operation controller  550  moves the object O using the holder  100  based on a movement plan of the object O modified by the movement plan modifier  546 . In addition, in a case where the score S calculated by the holding state determiner  545  is less than the second threshold K 2 , the operation controller  550  re-holds the object O using the holder  100  based on a hold retry operation plan of the object O generated by the hold retry operation generator  547 . 
     Next, one example of the flow of the process of the control device  500  will be described.  FIG. 11  is a flowchart showing one example of the flow of the process of the control device  500 . First, the holding operation generator  541  generates a holding operation plan for the object O. The operation controller  550  holds the object O positioned at the movement source S 1  by controlling the holder  100  and the moving mechanism  200  based on the holding operation plan generated by the holding operation generator  541  (S 101 ). In addition, the movement plan generator  542  generates a movement plan of the object O (S 102 ). 
     Next, the object determiner  530 , for example, determines whether or not the object O held by the holder  100  is a known object based on image data captured by the object detecting camera  300  (S 103 ). Here, the process of S 103  may be performed substantially simultaneously with the process of S 101  or S 102  or may be performed before the process of at least one of S 101  and S 102 . 
     In a case where the object O is determined as being a known object, the control device  500  proceeds to determination of a holding state (Step S 106 ) to be described later without performing a test operation. On the other hand, in a case where the object O is determined as not being a known object, the test operation generator  543  generates an operation plan of a test operation. The operation controller  550  performs a test operation in a state in which the object O is held by the holder  100  based on the operation plan of the test operation generated by the test operation generator  543  (S 104 ). At this time, the force sensor  401  measures a force and a moment acting on the force sensor  401  before the test operation and measures a force and a moment acting on the force sensor  401  during the test operation. 
     In a case where the test operation is performed, the parameter estimator  544  estimates a weight and a three-dimensional position of the center of gravity as parameters relating to the object O based on the information measured by the force sensor  401  (S 105 ). Here, the weight and the three-dimensional position of the center of gravity estimated by the parameter estimator  544  may be registered in the object DB  561  in association with the feature information of the object O. In such a case, in a case where the same object O is to be held next time, the test operation and the process of estimating the parameters may be omitted. 
     Next, the holding state determiner  545  determines a holding state of the holder  100  for the object O. Here, in a case where the object O is determined as being a known object in the process of S 103 , parameters relating to the object O are acquired from the object DB  561 . On the other hand, in a case where the object O is determined as being an unknown object in the process of S 103 , the parameters estimated by the parameter estimator  544  are used as parameters relating to the object O. 
     The holding state determiner  545  calculates the holding state as a score S, for example, based on Equation (1) or (2) described above (S 106 ). Then, the holding state determiner  545 , first, determines whether or not the object O is held sufficiently by the holder  100 , in other words, whether or not the object O can be transported without dropping the object O even in the movement plan (for example, a movement plan for moving the object O in a shortest time using the transporter  11 ) generated by the movement plan generator  542  (S 107 ). The process of S 107 , for example, is performed by comparing the score S calculated by the holding state determiner  545  with the first threshold K 1 . In a case where the score S is the first threshold K 1  or more, the holding state determiner  545  determines that the object O is held sufficiently by the holder  100 , and the object O can be transported without dropping the object O even in the movement plan generated by the movement plan generator  542 . In such a case, the operation controller  550  moves the object O based on the movement plan generated by the movement plan generator  542  (S 110 ). 
     In a case where the score S is less than the first threshold K 1  in the process of S 107 , the holding state determiner  545  determines that the holding of the object O using the holder  100  is not sufficient and there is a possibility of dropping the object O in the movement plan generated by the movement plan generator  542 . In such a case, the holding state determiner  545  determines whether or not the object O can be transported without dropping the object O in a case where the movement plan of the object O is modified (S 108 ). The process of this S 108 , for example, is performed by comparing the score S calculated by the holding state determiner  545  with the second threshold K 2 . 
     In a case where the score S is the second threshold K 2  or more in the process of S 108 , the holding state determiner  545  determines that the object O can be transported without being dropped in a case where the movement plan is modified. In such a case, the movement plan is modified by the movement plan modifier  546  (S 109 ). Then, the operation controller  550  moves the object O based on the movement plan modified by the movement plan modifier  546  (S 110 ). 
     On the other hand, in a case where the score S is less than the second threshold K 2  in the process of S 108 , the holding state determiner  545  determines that there is a possibility of dropping the object O even in a case where the movement plan is modified. In such a case, the hold retry operation generator  547  generates a hold retry operation plan. Then, operation controller  550  re-holds the object O based on the hold retry operation plan generated by the hold retry operation generator  547  (S 111 ). In this case, the process of S 106  and subsequent steps is performed. 
     According to such a configuration, the object O can be conveyed more efficiently. In other words, in a picking operation of an object O using a transporter, in order to perform the operation quickly and accurately, it is preferable to move the object in a shortest path in which the object O can be moved in a shortest time without being dropped in accordance with the features of the object O and the holding state of the holder  100 . For this reason, in order to move the holder  100  at a high speed and a high acceleration, it is necessary to check whether or not the holding state of the holder  100  is a holding state corresponding thereto. However, in a case where parameters relating to the object O are not clear, there are cases in which it is difficult to perform the checking described above. For this reason, in a case where the parameters relating to the object O are not clear (for example, a case in which the three-dimensional position of the center of gravity is not clear), a movement plan in which a movement speed and an acceleration of the holder  100  are suppressed such that the object O is not dropped is generated. In this case, there may be a case in which the object O cannot be efficiently transported. 
     On the other hand, in this embodiment, the transporter  11  includes the operation controller  550  that performs a test operation of moving the holder  100  in a state in which the object O is held by the holder  100  and the parameter estimator  544  that estimates at least one parameter relating to the object O based on a result of detection acquired by the force sensor  401  during the test operation. According to such a configuration, even in a case where the object O is unknown (a case in which parameters relating to the object O are not clear), the parameter relating to the object O is estimated through a test operation, and the holding state of the object O can be checked based on the estimated parameter. Accordingly, after a holding state corresponding to a movement plan of a high speed and a high acceleration is checked, the object O can be moved in accordance with the movement plan of a high speed and a high acceleration. In this way, the object O can be transported more efficiently. 
     In this embodiment, the test operation is performed before a conveyance operation of moving the object O toward the movement destination S 2 . According to such a configuration, by performing a test-dedicated operation before actually moving an object O, parameters relating to the object O can be estimated with high accuracy. 
     In this embodiment, the parameter estimator  544  does not estimate parameters relating to an object O in a case where the object O is determined as being an object of which the parameters are stored in the storage  560  and estimates the parameters relating to the object O in a case where the object O is determined as not being an object of which parameters are stored in the storage  560 . According to such a configuration, in a case where the parameters of an object O are known, a test operation and the process of estimating parameters can be omitted, and accordingly, more efficient conveyance can be realized. 
     In this embodiment, one of the parameters is the position of the center of gravity of the object O. According to such a configuration, the holding state of the object O can be determined also in consideration of a moment based on the position of the center of gravity of the object O. In this way, the holding state of the object O can be determined with a higher accuracy. 
     In this embodiment, the test operation includes an operation of inclining the holder  100  holding the object O. According to such a configuration, the three-dimensional position of the center of gravity of the object O can be calculated through a simple operation. For example, this test operation is performed at a position to which the holder  100  has lifted the object O from the movement source S 1  without moving the holder  100  toward the movement destination S 2 . According to such a configuration, in a case where the holding state of the holder  100  is unstable, the object O can be placed back immediately at the movement source S 1 , and the object O can be re-held by the holder  100 . Accordingly, the object O can be conveyed more efficiently. 
     The test operation includes an operation of applying an acceleration to the holder  100  holding the object O without inclining the holder  100 . According to such a configuration, for example, in a case where an object O is a heavy load, the test operation can be performed without inclining the object O. In addition, even in a case where the value of the coefficient α described above greatly changes in accordance with the posture of the holder, the test operation can be performed in a state in which the value of the coefficient α is large (a state in which it is more difficult to drop the object O). 
     In this embodiment, the test operation includes an operation of applying an acceleration to the object O by moving the holder  100  in a direction different from a direction toward the movement destination of the object O. According to such a configuration, the test operation can be performed using a safer direction, an area having a more spatial margin, or the like, and the degree of freedom of the test operation can be increased. 
     In this embodiment, in a case where the first acceleration that is a maximum acceleration in the first direction will act on the object O at the first time point, and the second acceleration that is a maximum acceleration in the second direction will act on the object O at the second time point in the movement plan of the object O toward the movement destination S 2 , the test operation includes an operation of applying the first acceleration to the object O in the first direction and applying the second acceleration to the object O in the second direction. According to such a configuration, the test operation can be performed in compliance with an actual movement plan. In this way, the holding state of the object O can be determined with a higher accuracy. 
     In this embodiment, the holding state determiner  545  determines a holding state of the object O using the holder  100  based on a value relating to a holding force detected by the holding force detecting sensor  402 , parameters relating to the object O estimated by the parameter estimator  544 , and the movement plan of the object O toward the movement destination S 2  of the object O. According to such a configuration, the holding state can be determined with a high accuracy in consideration of a moment acting on the object O and the like based on details (for example, a maximum acceleration acting on the object O) of the movement plan and the parameters relating to the object O. 
     Here, one example of a method of determining the first threshold K 1  and the second threshold K 2  will be described. The first threshold K 1  and the second threshold K 2 , for example, can be determined while the transporter  11  is operated through trial and error. For example, regarding the first threshold K 1 , a test operation is executed at a maximum acceleration that can be generated by the moving mechanism  200 , and, in a case where an object O is not dropped, a score S (S 1 ) at that time is set as the first threshold K 1 . Then, for an object O held next, similarly, a test operation is executed at the maximum acceleration that can be generated by the moving mechanism  200 , and, in a case where the object O is not dropped, and a score S (S 2 ) at that time is lower than the first threshold K 1 , the value of the first threshold K 1  is updated with the value of the score S (S 2 ). By repeating this operation, the first threshold K 1  can be determined. Accordingly, the value of the first threshold K 1  can be set to be small as possibly as can in a range in which the object O is not dropped. As a result, the number of times of moving the object O can be increased in the movement plan of a high speed and a high acceleration without modifying the movement plan. In this way, the object O can be efficiently conveyed. 
     Regarding the second threshold K 2 , a test operation is executed at the minimum acceleration that is allowed in time, and, in a case where the object O is not dropped, a score S (S 3 ) at that time is set as the second threshold K 2 . Then, for an object O held next, similarly, a test operation is executed at the minimum acceleration that is allowed in time, and, in a case where the object O is not dropped, and a score S (S 4 ) at that time is lower than the second threshold K 2 , the value of the second threshold K 2  is updated with the value of the score S (S 4 ). By repeating this operation, the second threshold K 2  can be determined. Accordingly, the value of the second threshold K 2  can be set to be small as possibly as can in a range in which the object O is not dropped. As a result, the number of times of moving the object O can be increased by only modifying the movement plan without re-holding the object O. In this way, the object O can be efficiently conveyed. 
     Second Embodiment 
     Next, a second embodiment will be described with reference to  FIGS. 12 to 14 . The second embodiment is different from the first embodiment in that a behavior monitor  403  monitoring a behavior of an object O is disposed. The other components other than those described below are similar to those according to the first embodiment. 
       FIG. 12  is a block diagram showing a system configuration of a transporter  11  according to the second embodiment. As shown in  FIG. 12 , in this embodiment, a measurer  400  includes the behavior monitor  403 . The behavior monitor  403  is provided at a holder  100  or a moving mechanism  200  and monitors a behavior of an object O during a test operation. Here, “a behavior of an object O” represents a relative movement of the object O with respect to the holder  100  and represents a vibration (shake) of the object O with respect to the holder  100 , a positional deviation of the object O with respect to the holder  100 , or the like. 
     The behavior monitor  403 , for example, is a camera that images an object O or a distance sensor that measures a distance between the object O and the behavior monitor  403 . A result of detection acquired by the behavior monitor  403  is output to a control device  500 . In addition, in a case where the behavior of the object O can be imaged during a test operation using an object detecting camera  300 , the object detecting camera  300  may function as one example of the behavior monitor  403 . 
       FIG. 13  is a diagram showing a first example of a test operation according to this embodiment. The behavior monitor  403  monitors a behavior of the object O in a case where the object O is inclined. For example, the behavior monitor  403  is disposed integrally with a part of the holder  100  or the moving mechanism  200  and is inclined together with the holder  100  in a case where the holder  100  is inclined. Accordingly, in a case where a behavior of the object O is not generated, a distance between the behavior monitor  403  and the object O is maintained as being constant. Accordingly, in a case where a behavior of the object O is generated, the behavior monitor  403  can perceive the behavior with a high accuracy. 
       FIG. 14  is a diagram showing a second example of a test operation according to this embodiment. The behavior monitor  403  monitors a behavior of the object O in a case where a translational acceleration is applied to the object O. For example, the behavior monitor  403  is disposed integrally with a part of the holder  100  or the moving mechanism  200  and is moved together with the holder  100  in a case where the holder  100  moves. Accordingly, in a case where a behavior is not generated in the object O, a distance between the behavior monitor  403  and the object O is maintained as being constant. Accordingly, in a case where a behavior of the object O is generated, the behavior monitor  403  can perceive the behavior with a high accuracy. 
     In addition, a holding force detecting sensor  402  can detect whether a holding force of the holder  100  for the object O decreases during a test operation in the first example and the second example of the test operation described above. For example, in the case of the holder  100  including a sucker  101 , the holding force detecting sensor  402  that is a pressure sensor can detect whether the holding force of the holder  100  for the object O decreases by detecting the pressure of the inside of the sucker  101  during the test operation. On the other hand, in the case of the holder  100  including a pinching member  102 , the holding force detecting sensor  402  that is a pressure sensitive sensor can detect whether the holding force of the holder  100  for the object O decreases by detecting a contact pressure between the pinching member  102  and the object O during the test operation. 
     Next, referring back to  FIG. 12 , the description will be continued. In this embodiment, the control device  500  includes a behavior detector  548  that detects the behavior of the object O based on a result of monitoring executed by the behavior monitor  403 . The behavior detector  548 , for example, detects a behavior of the object O based on an image analysis of an image analyzer  520  for image data acquired by the behavior monitor  403  that is a camera. In addition, the behavior detector  548 , for example, detects a behavior of the object O based on information acquired by the behavior monitor  403  that is a distance sensor. 
     In this embodiment, a holding state determiner  545  determines a holding state of the object O using the holder  100  also based on the behavior of the object O during the test operation in addition to the value relating to the holding force detected by the holding force detecting sensor  402 , parameters relating to the object O, and the movement plan of the object O toward the movement destination S 2  of the object O. In other words, the holding state determiner  545  compares the magnitude of the behavior of the object O during the test operation with a threshold and determines that the holding state for the object O is weak in a case where the magnitude of the behavior of the object O is larger than the threshold. For example, in a case where the magnitude of the behavior of the object O is larger than the threshold, the holding state determiner  545  modifies the score S described above such that the score S is decreased. 
     In addition, in a case where a decrease in the holding force of the holder  100  for the object O is determined during the test operation, the holding state determiner  545  reflects a result thereof on the holding state of the object O using the holder  100 . For example, in a case where a decrease in the holding force during a test operation is larger than the threshold, the holding state determiner  545  modifies the score S described above such that the score S is decreased. 
     According to such a configuration, in addition to the actions according to the first embodiment described above, the holding state of the object O can be determined with a higher accuracy. 
     Modified Example of Second Embodiment 
     Next, a modified example of the second embodiment will be described with reference to  FIG. 15 . In this modified example, a frictional coefficient between the holder  100  and the object O is estimated as one of parameters relating to the object O, which is different from the second embodiment. Components other than those described below are similar to those according to the second embodiment. 
       FIG. 15  is a front view showing the holder  100  according to this modified example. As illustrated in  FIG. 15 , in a test operation, in a case where a force F acts in a direction that is substantially orthogonal to a direction in which the holder  100  and the object O are aligned in a state in which the holder  100  holds the object O with a holding force F′, the object O is assumed to deviate from the holder  100 . In this case, in a case where a frictional coefficient between the holder  100  and the object O is denoted by μ, the following Equation (3) is satisfied.
 
F=μF′  (3)
 
     In other words, in a case where the object O deviates from the holder  100 , the parameter estimator  544  estimates a frictional coefficient between the holder  100  and the object O based on the force F applied to the object O and the holding force F′. 
     In this embodiment, the holding state determiner  545  determines the holding state of the object O also based on the frictional coefficient between the holder  100  and the object O. In other words, the holding state determiner  545  may set or modify the value of the coefficient β 2  in Equation (2) described above or modify the value of the coefficient α in Equation (1) or (2) described above based on the frictional coefficient between the holder  100  and the object O that is estimated by the parameter estimator  544 . According to such a configuration, the holding state of the object O can be determined with a higher accuracy. 
     Third Embodiment 
     Next, a third embodiment will be described with reference to  FIG. 16 . In the third embodiment, several functional units provided at the control device  500  in the first embodiment are provided at a management device  12 , which is different from the first embodiment. Components other than those described below are similar to those according to the first embodiment. 
       FIG. 16  is a diagram schematically showing a transport system  1  according to this embodiment. As shown in  FIG. 16 , in this embodiment, at least the information acquirer  510 , the image analyzer  520 , the object determiner  530 , the storage  560 , the test operation generator  543 , and the parameter estimator  544  are provided in the management device  12 . The test operation generator  543  outputs a control direction relating to a test operation to the control device  500  of the transporter  11 . 
     According to such a configuration, similar to the first embodiment described above, the object O can be moved more efficiently. 
     As above, the first to third embodiments and modified examples thereof have been described. However, the embodiments are not limited to the examples described above. The first to third embodiments may be combined and executed. 
     For example, the information acquirer  510  may acquire information that can be used for identifying an object O not from the object detecting camera  300  but from the management device  12  or any other external apparatus through a network. For example, the information acquirer  510  may acquire information acquired from an external apparatus in a case where the object O is collected or loaded as the information that can be used for identifying the object O. In such a case, the object detecting camera  300  may be omitted. 
     For example, a contact-type switch may be provided in the holder  100  (for example, the sucker  101  or the pinching member  102 ). The contact-type switch transitions from an off-state to an on-state by being brought into contact with the object O in a case where the object O is held in the holder  100 . In a case where a predetermined condition is satisfied (for example, in a case where the object O is known), the holding state determiner  545  may determine the holding state for the object O based on the on/off state of a switch provided in the holder  100  instead of calculating the score S. Accordingly, in a case where the predetermined condition is satisfied, the object O can be moved based on determination of the holding state, which is simpler. 
     According to at least one of the embodiments described above, by including the operation controller configured to execute a test operation of moving an object using the holder and the parameter estimator configured to estimate at least one parameter relating to the object based on a result of detection acquired by a sensor during the test operation, the object can be moved more efficiently. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.