Work transport system

Abstract

This invention provides a workpiece handling system that can hold a workpiece without a large load acting on the robotic device, even when the workpiece undergoes a change in posture due to being lifted up or lowered from the work surface. [Solution] The workpiece transport system 10 comprises a hoisting machine 2, a lifting device 4, a robot device 3 for moving the lifting device 4, a crane 1 for following the hoisting machine 2, and a transport control unit for coordinating the operation of the robot device 3 and the hoisting machine 2. The hoisting machine 2 comprises a drive motor for rotating a winding section that raises and lowers the chain Cl, a load calculation unit for calculating the tension applied to the chain Cl, and a motor control unit that uses a specified load instructed by the transport control unit or the robot device 3 as a reference load and torque-controls the drive motor based on the tension and the reference load. When transporting a workpiece Wo in a predetermined process, the transport control unit or the robot device 3 changes the specified load according to the predetermined process and the position of the lifting device 4.

Description

[Technical Field]

[0001] The present invention relates to a workpiece conveyance system. [Background Art]

[0002] Patent Document 1 discloses a conveyance system that conveys a workpiece by causing a crane and a robot to cooperate with each other. The conveyance system includes a control device that controls a lifting servomotor of the crane by current control and controls a servomotor of the robot by position control, and enables conveyance of workpieces of various weights using the robot while preventing an increase in size and cost of the robot.

[0003] The control device applies a predetermined current value determined in advance according to the weight of the workpiece and the lifting speed of the workpiece to the lifting servomotor. Accordingly, the robot can move the workpiece with substantially no load in the vertical direction. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] WO2016 / 067457 A1 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] When lifting a workpiece with a crane hoist, the lower end of the hoist's rope is attached to a lifting device or the upper lifting part of the workpiece for lifting. If there is no mechanism to regulate the workpiece's posture, the workpiece does not lift off the ground (ground lift) as the rope is wound up, but rather the workpiece's posture changes as it lifts off the ground. In this case, the tension on the crane rope is not uniform and changes with the amount of rope wound up. In a transport system that uses a crane and a robot to transport a workpiece, the load acting on the robot cannot be controlled by the current value (output torque) of the lifting servo motor based solely on information about the workpiece's weight and lifting speed.

[0006] Similarly, when lowering a workpiece lifted by a crane onto a mounting surface or platform, depending on the shape of the workpiece, it may be necessary for a portion of the lower end to touch the ground before the workpiece's orientation changes as it is lowered. In such cases, the load acting on the robot cannot be controlled by the current value (output torque) of the lifting servo motor based solely on the weight of the workpiece and the lifting speed of the workpiece.

[0007] Furthermore, when the lifting servo motors of a crane are controlled by a control device that controls a robot, either the crane alone cannot control the lifting servo motors by current, or it is necessary to have two control devices capable of current control, one for the crane and one for the robot control device.

[0008] This invention has been made in view of the above circumstances, and aims to provide a workpiece transport system in which a large load is not applied to the robotic device that moves the workpiece, even when the workpiece undergoes a change in posture when transported by a hoisting machine. [Means for solving the problem]

[0009] One aspect of the present invention is a workpiece transport system comprising: a hoisting machine that raises and lowers a workpiece by winding up and down a chain or linear member; a lifting device connected to the lower end of the chain or linear member to engage with and suspend the workpiece; a robotic device connected to the lifting device to move the lifting device; a crane that moves the hoisting machine to be positioned directly above the lifting device as the lifting device is moved by the robotic device; and a transport control unit that coordinates the operation of the robotic device and the hoisting machine. The hoisting machine comprises: a winding section that winds up and down the chain or linear member; a drive motor that generates a driving force to rotate the winding section; a load calculation section that calculates the tension applied to the chain or linear member; and a motor control unit that uses a specified load instructed by the transport control unit or robotic device as a reference load and torque-controls the drive motor based on the tension and the reference load. When transporting a workpiece in a predetermined process, the transport control unit or robotic device changes the specified load according to the predetermined process and the position of the lifting device.

[0010] Furthermore, one aspect of the present invention provides a workpiece transport system comprising: a hoisting machine that raises and lowers a workpiece by winding up and down a chain or linear member; a lifting device connected to the lower end of the chain or linear member to engage with and suspend the workpiece; a robotic device connected to the lifting device to move the lifting device; a crane that moves the hoisting machine to be positioned directly above the lifting device as the robotic device moves the lifting device; and a transport control unit that coordinates the operation of the robotic device and the hoisting machine. The hoisting machine comprises a winding section that winds up and down the chain or linear member; a drive motor that generates a driving force to rotate the winding section; a load calculation section that calculates the tension applied to the chain or linear member; and a motor control unit that torque-controls the drive motor based on a reference load and tension determined for each workpiece. When transporting a workpiece in a predetermined process, the reference load is changed according to the predetermined process and the position of the lifting device. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a workpiece transport system in which a large load is not applied to the robotic device that moves the workpiece, even when the workpiece undergoes a change in posture while being transported by a hoisting machine. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a configuration diagram showing the workpiece transport system according to this embodiment. [Figure 2] Figure 2 is a diagram showing the control configuration of the hoisting machine. [Figure 3] Figure 3 is a configuration diagram showing the control configuration of the workpiece transport system according to this embodiment. [Figure 4] Figure 4 is an operation diagram showing the operation of the workpiece transport system according to this embodiment. [Figure 5] Figure 5 is an explanatory diagram illustrating the tension change during ground clearance of the workpiece transport system according to this embodiment. [Figure 6] Figure 6 is an explanatory diagram illustrating the teaching process during ground clearance of the workpiece transport system according to this embodiment. [Figure 7] Figure 7 is an operation table showing the operation of each component of the workpiece transport system according to this embodiment. [Figure 8] Figure 8 is a time chart showing the change in the set load in the workpiece transport system according to this embodiment. [Modes for carrying out the invention]

[0013] The workpiece transport system 10 according to this embodiment will be described below with reference to the drawings.

[0014] [Work transport system] [structure] First, the structure of the workpiece transport system 10 will be explained with reference to Figures 1, 2, and 3.

[0015] As shown in Figure 1, the workpiece transport system 10 comprises a crane 1, a lifting device 4, a hoisting machine 2, a robot device 3, and a transport control unit 5 (see Figure 3).

[0016] (crane) The crane 1 comprises a traveling rail 11 and a traversing rail 12. The traveling rail 11 is two rail members fixed to a ceiling or the like. The traversing rail 12 is a rail member with both ends thereof respectively suspended from the two traveling rails 11 via traveling trolleys (not shown), and is movable in the longitudinal direction of the traveling rails 11. The traversing rail 12 is provided with a traversing trolley (not shown) that traverses along the traversing rail, and the hoist 2 can be suspended from the traversing trolley.

[0017] In the hoist 2 suspended from the traversing trolley of the crane 1, when the robot device 3 moves the hanger 4 in the horizontal direction, the hoist body 22 is pulled via the chain of the hoist 2 or a load chain Cl as a linear member. Accordingly, the crane 1 is a driven horizontal moving device that moves the hoist 2 in the horizontal direction, which enables the hoist body 22 to be always positioned substantially directly above the hanger 4.

[0018] (Hanger) The hanger 4 has a connecting member 41 fixed to a lower hook 21 connected to the lower end of the load chain Cl, or fixed to the lower end of the load chain Cl via a shackle 43 or the like. An attachment / detachment portion 44 to and from which a hand portion 37a of the robot device 3 (described later) can be attached and detached is provided on the upper surface of the connecting member 41. The connecting member 41 can have any shape depending on the type of the workpiece Wo disposed below. For example, as shown in Fig. 1, a connecting tool 42 may be provided on the lower surface of the connecting member 41, and the workpiece Wo may be suspended from the connecting tool 42.

[0019] In the plate-shaped connecting member 41 shown in Fig. 1, a suction portion may be provided on the lower surface to suck and engage a plate-shaped workpiece Wo such as glass. Depending on the shape of the workpiece, the lower hook 21 can be used as the hanger 4. In this case, the lower hook 21 is engaged with a hanging portion provided on the workpiece Wo to lift the workpiece Wo.

[0020] (Hoist) The hoisting machine 2 can raise and lower the lifting device 4 by winding up and down the load chain Cl. Furthermore, the hoisting machine 2 is mounted on a driven trolley (not shown) that can move freely along the traverse rail 12, and the traverse rail 12 is equipped with a traveling trolley (not shown) that can move freely along the traveling rail 11, so that the hoisting machine 2 can move freely in the horizontal direction.Therefore, when the lifting device 4 is moved horizontally by the robot device 3, the hoisting machine 2 can follow the movement and position itself directly above the lifting device 4.

[0021] The hoisting machine 2 is equipped with a lower hook 21 connected to the lower end of the load chain Cl, and has a cylinder operating device 6 on the upper part of the lower hook, which is an operating device that allows an operator to operate the lower hook 21 and an operating switch 61 while holding it in their hand. The upper end of the cylinder operating device 6 is connected to the lower end of the load chain Cl, and the lower hook 21 is connected to the load chain Cl via the cylinder operating device 6.

[0022] As shown in Figure 2, the hoisting machine 2 comprises a load chain Cl, a lower hook 21 connected to the lower end of the load chain Cl, a hoisting machine body 22, an upper hook 23, and a chain bucket 24 for accommodating the hoisted load chain Cl.

[0023] The chain bucket 24 stores and holds the unloaded load chain Cl, which has already been wound up by the load sheave 25, which serves as the winding section.

[0024] The lower hook 21 is a locking device connected to the lower end of the load-side load chain Cl via a cylinder operating device 6, and is capable of locking onto a workpiece Wo to be lifted by the hoisting machine 2, or locking onto a lifting device 4 for the workpiece Wo to be lifted by the hoisting machine 2.

[0025] The hoisting machine body 22 is suspended via an upper hook 23 from a driven traverse trolley (not shown) positioned on the traverse rail of the crane 1. Inside the housing, the hoisting machine body 22 includes a drive motor 26, a reduction mechanism 27, a brake mechanism 28, a load sheave 25 for winding up the load chain Cl, a load sensor 22a, a driver 29, and a hoisting machine control unit 20.

[0026] The drive motor 26 is a motor that provides the driving force to drive the load sheave 25. The drive motor 26 is a servo motor equipped with an encoder 26a capable of outputting position information for detecting the unwinding length of the load chain Cl, and is preferably an AC servo motor. While the AC servo motor is preferably a synchronous motor, the drive motor 26 may also be a combination of an induction motor and an encoder driven and controlled by an inverter control device.

[0027] The reduction mechanism 27 reduces the rotation of the drive motor 26 and transmits it to the load sheave 25. The brake mechanism 28 releases the braking force by electromagnetic force when the drive motor 26 is operating, and generates a braking force to hold the workpiece Wo lifted by the hoisting machine 2 when the drive motor 26 is not operating.

[0028] The load sheave 25 rotates to wind up and down the load chain Cl. The load sheave 25 has multiple chain pockets (not shown) along its outer circumference into which the metal rings of the load chain Cl fit.

[0029] The load sensor 22a measures the load applied to the upper hook 23. The load sensor 22a measures and detects the total load of the hoisting machine body 22's own weight and the tension applied to the load chain Cl. The hoisting machine control unit 20 calculates the tension of the load chain Cl, which is the load applied to the load sheave 25 via the load chain Cl, by subtracting the body's own weight, etc., from the total load measured and detected using the load sensor 22a.

[0030] The load sensor 22a is attached, for example, to a mounting shaft for attaching the upper hook 23 to the hoisting machine body 22. In this embodiment, the load sensor 22a is a load cell equipped with a strain gauge.

[0031] In addition to the above, the load sensor 22a may be positioned between the upper hook 23 and the crane trolley, between the lower hook 21 and the connecting member 41, or between the end of the load chain Cl and the lower hook 21. The load sensor 22a, which detects the tension of the load chain Cl, also conceptually includes a shaft torque detection means or motor torque detection means that detects the shaft torque of the shaft connected to the rotating shaft of the load sheave 25.

[0032] The driver 29 adjusts the power supplied from an external or internal battery (not shown) to an appropriate level based on the current value of the drive motor 26, the output value of the encoder 26a, and the command value for motor drive control provided by the hoisting machine control unit 20, and supplies it to the drive motor 26, causing it to rotate. Since the drive motor 26 is a servo motor, the driver 29 is a servo driver.

[0033] The driver 29 has at least a torque control mode and controls the drive motor 26 based on commands from the hoisting machine control unit 20.

[0034] The hoisting machine control unit 20 calculates the load torque applied to the drive motor 26 via the load sheave 25 from the load load detected by the load sensor 22a, and provides command values ​​such as position, speed, and torque to the driver 29. The hoisting machine control unit 20 is a computer equipped with, for example, a CPU (Central Processing Unit), memory 20a (RAM (Random Access Memory), ROM (Read Only Memory), internal storage, external storage device, etc.), and an input / output interface. The memory 20a stores the control program and various parameters for operation in torque control mode.

[0035] Furthermore, the hoisting machine control unit 20 includes a load calculation unit 20b and a float calculation unit 20c as a motor control unit. These load calculation unit 20b and float calculation unit 20c are functionally realized by reading the control program and various parameters described above from the memory 20a and performing calculations on the CPU.

[0036] The load calculation unit 20b calculates the load torque applied to the drive motor 26 via the load sheave 25 from the load chain Cl, based on the load detected by the load sensor 22a.

[0037] The float calculation unit 20c calculates the torque command value Tm when the operating mode is float mode. The torque command value Tm is calculated based on the reference load and the tension on the load chain Cl, and is output to the driver 29. The reference load is set as the set load Wl0 in float mode, and the tension on the load chain Cl is calculated as the measured load Wl by the load calculation unit 20b as needed.

[0038] (Robot device) The robot device 3 has legs 31, three joints 32, 33, and 34, and three arms 35, 36, and 37. The hand portion 37a of the arm 37 at the end is detachably connected to a detachable part 44 provided on the connecting member 41 of the lifting device 4. The robot device 3 can move the lifting device 4 to a desired position and control the posture of the lifting device 4 by operating the joints 32, 33, and 34 and the arms 35, 36, and 37.

[0039] Furthermore, as shown in Figure 3, the leg portion 31 has a first motor 31a, the first joint portion 32 has a second motor 32a, the second joint portion 33 has a third motor 33a, the third joint portion 34 has a fourth motor 34a, the first arm 35 has a fifth motor 35a, and the second arm 36 has a sixth motor 36a.

[0040] Returning to Figure 1, the leg portion 31 is erected upward from the installation surface such as the floor and rotatably supports the first joint portion 32. The leg portion 31 houses the first motor 31a inside, and the first joint portion 32, which is in contact with the leg portion 31, can be rotated about an axis perpendicular to the installation surface (hereinafter referred to as the "V-axis") by driving the first motor 31a.

[0041] The first joint 32 is provided on the upper end side of the leg portion 31, and the first arm 35 is attached to it in a rotatable manner. The first joint 32 has a second motor 32a. The second motor 32a rotates the first arm 35 about an axis parallel to the mounting surface (hereinafter referred to as the "H axis"). Therefore, the first arm 35 can rotate about the V axis by the leg portion 31 and can also rotate about the H axis by the first joint 32.

[0042] The second joint 33 is rotatably attached to the tip of the first arm 35, and the second arm 36 is attached in a rotatable manner. The second joint 33 has a third motor 33a. The third motor 33a rotates the second arm 36 about the H axis. Therefore, the second arm 36 is rotatable about the V axis by the leg portion 31 and also rotatable about the H axis about the second joint 33.

[0043] The third joint 34 is rotatably attached to the tip of the second arm 36, and the third arm 37 is attached in a rotatable state. The third joint 34 has a fourth motor 34a. The fourth motor 34a rotates the third arm 37 about the H axis and keeps the third arm 37 at the same angle so that it always extends vertically. The third arm 37 has a hand portion 37a and detachably holds the connecting member 41 of the suspension device 4 by an actuator using magnetic force or air (not shown).

[0044] As shown in Figure 3, the torque sensors 31b to 36b are incorporated into the output sections of the motors 31a to 36a of the robot device 3, and transmit the torque applied to each motor 31a to 36a of the robot device 3 to the robot control unit 30. Alternatively, external force sensors such as strain gauges may be used instead of the torque sensors 31b to 36b by providing them on the sides of each joint 32 to 34 and each arm 35 and 36.

[0045] To ensure the safety of the system, if an unexpected external force is applied to the robot device 3, the torque sensors 31b to 36b detect the external force and immediately stop the robot device 3. Furthermore, when the robot device 3 detects the external force, a message is transmitted to the transport control unit 5, causing the operation of the hoisting machine 2 to immediately stop.

[0046] The load applied to the tip of the hand portion 37a of the robot device 3 can be calculated by utilizing the detection values ​​of each torque sensor 31b to 36b incorporated into the robot device 3 and calculating the resultant force of these detection values. In other words, the load applied to the tip of the hand portion 37a can be calculated by utilizing the safety functions originally provided in the robot device 3, as described above. The robot device 3 may also have a force sensor (not shown) on the hand portion 37a for detecting the load applied to the hand portion 37a via the lifting device 4.

[0047] (Transportation control unit) The transport control unit 5 (Figure 3) receives operation commands from the operator and transmits signals to the hoisting machine 2 and robot device 3 to control the transport of the workpiece Wo. The detailed control contents of the transport control unit 5 will be described later.

[0048] [control] (Work transport system) Next, the control configuration of the workpiece transport system 10 will be described with reference to Figure 3. Figure 3 is a configuration diagram showing the control configuration of the workpiece transport system 10 according to this embodiment.

[0049] The workpiece transport system 10 includes a transport control unit 5, a hoisting machine control unit 20, and a robot control unit 30 as control units.

[0050] As already described above, the hoisting machine control unit 20 is a computer or integrated circuit equipped with, for example, a CPU (Central Processing Unit), memory (RAM (Random Access Memory), ROM (Read Only Memory), internal storage, external storage device, etc.), input / output interfaces, etc. The operator switch 51 is a switch operated by an operator and is located on a transport work panel near the transport control unit 5.

[0051] The transport control unit 5 performs the control necessary for the coordinated operation of the hoisting machine 2 and the robot device 3. The transport control unit 5 transmits signals related to control commands to the hoisting machine control unit 20 and the robot control unit 30. The transport control unit 5 can be configured to be attached to the robot control unit 30, in which case the communication control unit of the robot control unit 30 and the communication control unit 20d of the hoisting machine control unit 20 transmit and receive control commands and information necessary for coordinated operation.

[0052] As described above, the hoisting machine control unit 20 transmits a torque command value Tm to the driver 29 and operates the drive motor 26 based on information such as operation commands from the cylinder operating device 6, commands transmitted from the transport control unit 5, signals indicating the status of the robot control unit 30, and load detected by the load sensor 22a, thereby raising and lowering the lifting device 4 suspended from the hoisting machine 2 to assist the operation of the robot device 3.

[0053] Based on the control signals transmitted from the transport control unit 5, the robot control unit 30 transmits control signals to the drivers 30a to 30f of each part having motors 31a to 36a, so that the motors 31a to 36a can be controlled in a coordinated manner, so that the robot device 3 can perform the desired movement.

[0054] The operator switch 51 is a switch for transmitting control signals to the transport control unit 5 that indicate that the operator has operated it to start and stop the work transport system 10. It is preferable that the operator switch 51 also has the function of the operation switch 61 provided on the cylinder operating device 6.

[0055] The hoisting machine 2 and the robot device 3 are connected via Ethernet IP communication through the transport control unit 5. The hoisting machine 2 receives information such as the operating mode, specified load, and position of the hand part 37a of the robot device 3, and transmits information on the measured load Wl and the unwinding length of the load chain Cl to the robot device 3. The robot device 3 transmits the operating mode, specified load, and target position during position control to the hoisting machine 2.

[0056] (Float mode) Next, the float mode, which is performed by the hoisting machine control unit 20 when the workpiece Wo is transported by the workpiece transport system 10, will be explained with reference to Figures 2 and 3. The float mode is an operation mode in which the hoisting machine is raised and lowered by detecting the tension on the load chain Cl, and is a control mode for the hoisting machine that does not require speed commands or target position commands from operation switches or the like.

[0057] In float mode, the hoisting machine control unit 20 continuously calculates the tension (measured load Wl) applied to the load chain Cl, which is the load that attempts to rotate the load sheave 25 in the lowering direction, using the load calculation unit 20b based on the output value of the load sensor 22a.

[0058] The measured load Wl is the load obtained by subtracting the weight of the main unit, etc., from the load value measured by the load sensor 22a, and is calculated by the load calculation unit 20b in the hoisting machine control unit 20.

[0059] In float mode, the operator's operating force Ws applied in the hoisting direction to the workpiece Wo being lifted by the hoisting machine 2 and the lower hook 21 is detected, and the hoisting and lowering of the load chain Cl is controlled by torque. The torque to be output by the drive motor 26 to hold the workpiece Wo being lifted by the hoisting machine 2 is calculated from the reference load. The reference load is stored in a predetermined memory as the set load Wl0, and its value is updated as needed. The operating force Ws is calculated from the measured load Wl and the set load Wl0 by the following equation (Equation 1).

[0060] Ws = Wl0 - Wl ... (Equation 1) In normal float mode, the set load Wl0 can be set by recalling the reference load for each workpiece from a pre-stored memory according to the type of workpiece, or by lifting the workpiece Wo and setting the value of the measured load Wl at that time as the set load Wl0. In the coordinated float mode of the workpiece transport system, the value of the instructed load commanded from the cooperating device is set as the set load Wl0. In this embodiment, the cooperating device is the robot device 3, and the value of the specified load is commanded to the hoisting machine 2 from the robot control unit 30 or the transport control unit 5. In normal float mode, the reference load is set as the set load Wl0 when the float mode starts. In contrast, in coordinated float mode, the set load Wl0 is repeatedly updated based on commands or information from the cooperating device while the coordinated float mode is in operation. The operating force Ws is calculated from the latest set load Wl0 and the latest measured load Wl.

[0061] The float calculation unit 20c calculates the torque command value Tm using the following equations (Equation 2), (Equation 3), and (Equation 4).

[0062] Tm0 = (1 / i) × r × Wl0 ... (Equation 2) Th=(1 / i)×r×Ws (Formula 3) Tm=Tm0+Kl×Th...(Formula 4) i is the reduction ratio of the reduction mechanism 27, r is the working radius of the load sheave 25, Kl is the gain, and the operating force Ws is the force in the hoisting and lowering direction applied by the robot device 3 to the lifting device 4 via the hand part 37a. If an external force is applied from the robot device 3 in the vertical direction of the lifting device 4, that external force is calculated as the operating force Ws.

[0063] Specifically, the hoisting machine control unit 20 calculates the reference torque Tm0, which is the torque of the drive motor 26 corresponding to the set load Wl0, using (Equation 2). Next, it calculates the increasing / decreasing motor torque Th, which corresponds to the operating force Ws, using (Equation 3). Then, it calculates the torque command value Tm to be output by the drive motor 26 using (Equation 4) and commands the driver 29.

[0064] Therefore, in float mode, torque control is performed based on a reference torque Tm0 corresponding to the set load Wl0 and an increasing / decreasing motor torque Th corresponding to the operating force Ws obtained from the difference between the set load Wl0 and the measured load Wl which changes due to the external force. When the operating force Ws applied to the lifting device 4 via the hand unit 37a is zero, the drive motor 26 is controlled to output the reference torque Tm0. The float calculation unit 20c calculates the torque command value Tm using the above formulas (formulas 1 to 4) based on the set load Wl0 set when starting normal float mode in normal float mode, and in linked float mode, it repeatedly updates the set load Wl0 based on commands or information from the linked device and calculates the torque command value Tm using the above formulas (formulas 1) to (formulas 4) based on the updated set load Wl0.

[0065] [Operation] The operation of the workpiece transport system 10 according to this embodiment will be described with reference to Figure 4. In this embodiment, the workpiece transport system 10 performs the task of transporting the workpiece Wo from a predetermined position to another target position.

[0066] The workpiece Wo is heavy, exceeding the allowable load that the robot device 3 can handle. Therefore, the hoisting machine 2 supports the weight of the workpiece Wo, and in that state, the robot device 3 moves the workpiece Wo in three dimensions.

[0067] At this time, the hoisting machine control unit 20 receives the specified load information and the linked float mode command from the transport control unit 5, sets the set load Wl0 to the value of the specified load information, and switches to linked float mode. As a result, the hoisting machine 2 is controlled in linked float mode so that no vertical load is applied to the tip of the robot device 3. When the hoisting machine control unit 20 receives the linked float mode command, it repeatedly updates the set load Wl0 with the specified load information transmitted from the transport control unit 5.

[0068] The transport control unit 5 only needs to transmit the load it wants the hoisting machine 2 to bear as specified load information according to the transport status, so the robot device 3 can move the workpiece Wo in three dimensions with almost no vertical load. In addition, because the hoisting machine 2 is in float mode, the robot device 3 can move the lifting device 4 within the allowable load, so it can be controlled by position control.

[0069] The process by which the workpiece transport system 10 transports the workpiece Wo will be described.

[0070] As shown in Figure 4A, the workpiece transport system 10 moves the lifting device 4, which is connected to the tip of the robot device 3, to the position of the workpiece Wo, which is stationary on the work surface F. At this time, the hoisting machine control unit 20 receives a normal float mode command from the transport control unit 5 and operates in normal float mode.

[0071] Subsequently, the robot device 3 raises the lifting device 4 so that it engages with the workpiece Wo, or so that the lifting device 4 engages with the workpiece Wo. At this time, before starting to raise the lifting device 4, the transport control unit 5 outputs a command to the hoisting machine control unit 20 to switch to linked float mode. Then, while raising the lifting device 4, the transport control unit 5 transmits the vertical load that the hoisting machine 2 should bear according to the position of the lifting device as specified load information to the hoisting machine control unit 20. The hoisting machine control unit 20 repeatedly sets the value of the specified load information as the set load Wl0, and calculates the torque command value Tm from the latest measured load Wl and the latest set load Wl0, and outputs it to the driver 29.

[0072] As a result, the hoisting machine 2 raises and lowers the load chain Cl to follow the raising and lowering of the lifting device 4 being transported by the robot device 3, thereby bearing the vertical load on the lifting device 4. At this time, ground clearance is performed, and as shown in Figure 4B, the workpiece Wo is lifted by the hoisting machine 2 and the robot device 3 with its entire load. This allows the robot device 3 to lift the workpiece Wo within the allowable load. Ground clearance will be described later. After ground clearance, the transport control unit 5 outputs a command to the hoisting machine control unit 20, along with reference load information, to switch to normal float mode.

[0073] As shown in Figure 4C, the workpiece transport system 10 operates the robotic device 3 while the load of the workpiece Wo is borne by the hoisting machine 2 in normal float mode, thereby transporting the workpiece Wo to a predetermined transport position in conjunction with the lifting device 4.

[0074] As shown in Figure 4D, the workpiece transport system 10 transports the workpiece Wo to a position directly above the target landing position. Then, the transport control unit 5 outputs a command to the hoisting machine control unit 20 to switch to the linked float mode. The transport control unit 5 then lowers the lifting device 4 so that the workpiece Wo lands, while transmitting the specified load information (the vertical load to be borne by the hoisting machine 2) from the transport control unit 5 to the hoisting machine control unit 20. This allows the robot device 3 to land the workpiece Wo within the allowable load. After landing, the transport control unit 5 outputs a command to the hoisting machine control unit 20 to switch to the normal float mode, along with reference load information.

[0075] (Ground cutting process) Ground lifting refers to the process of lifting the workpiece Wo from the mounting surface or platform on which it is placed using the hoisting machine 2. When lifting a workpiece with essentially a single chain or rope, if the center of gravity of the workpiece is not located on the extension of the vertically hanging line of the chain or rope, the workpiece's posture will change as it is lifted while the chain or rope is being wound up by the hoisting machine. Therefore, during the ground lifting process, the load of the workpiece is borne by the hoisting machine and the mounting surface, and the proportion of this burden depends on the shape of the workpiece and lifting equipment, as well as the position of the center of gravity and the hoisting machine.

[0076] As shown in Figures 4A and 4B, when the workpiece transport system 10 lifts the workpiece Wo from the work ground F to perform ground clearance, the posture of the workpiece Wo may change as it is lifted. In addition, there are cases where it is desired to change the posture of the workpiece Wo when it is placed on the ground from its posture before transport. In this case, the posture of the workpiece Wo is often changed during the ground clearance process to match the posture at which it will be placed on the ground while it is being lifted.

[0077] If there is no change in the posture of the workpiece Wo, the set load Wl0 can be set linearly according to the lifting position of the lifting device 4, taking into account the elastic deformation of each part. However, if the posture of the workpiece Wo changes during lifting, it may not be possible to set the set load Wl0 uniformly. If the workpiece is lifted with an inappropriate set load Wl0 relative to the position of the lifting device 4, an external force exceeding the allowable range may be applied to the robot device 3.

[0078] For example, in the initial stages of the ground cutting process, the workpiece Wo is in contact with the work ground F. As the lifting device 4 rises, a portion of the workpiece Wo remains in contact with the ground while its posture changes. When it reaches a predetermined height, the contact portion of the workpiece Wo separates upward from the work ground F. In such a case, the appropriate reference load changes in a complex manner.

[0079] Thus, if the shape of the workpiece Wo causes a change in posture during ground cutting, the specified load information (set load Wl0) to be instructed from the robot device 3 to the hoisting machine 2 is stored in the robot device 3 as a pre-calculated table or a pre-measured table, so as to change according to the position of the lifting device 4.

[0080] The following explains how to determine the specified load (set load Wl0) to be instructed to the hoisting machine 2 during ground cutting, divided into cases where the change in posture during ground cutting can be modeled and cases where the change in posture cannot be modeled. Note that in both cases, this is a task performed in advance, not during actual transport.

[0081] (Can be modeled) First, referring to Figure 5, we will explain the cases in which the change in posture during ground cutting can be modeled.

[0082] As shown in Figure 5A, if the workpiece Wo is hemispherical in shape and is stationary with its spherical surface in contact with the work surface F, lifting a point near the edge of the workpiece Wo will cause the workpiece Wo to rotate from position C to position D. At this time, since the shape of the workpiece Wo is known to be hemispherical, it is possible to replace it with a table as a shape model, and if the position of the lifting device 4 or the hand part 37a is known, the vertical load required to hold the workpiece Wo, i.e., the vertical load on the lifting device 4, can also be uniquely calculated.

[0083] Figure 5B is a table showing the relationship between the height of the lifting device 4 and the load applied to it during the transition of the workpiece Wo from state C to state D. Since the robot device 3 operates using position control, it knows the height of the lifting device 4 and reads the corresponding specified load (set load Wl0) from the table according to the height of the lifting device 4 and instructs the hoisting machine 2. Note that the relationship between the height of the lifting device 4 and the load applied to it may be stored as a function instead of a table.

[0084] (Not modelable) Next, referring to Figure 6, we will explain the cases where the change in posture during ground cutting cannot be modeled.

[0085] Cases where posture changes cannot be modeled include those where the shape of the workpiece Wo is complex and the relationship between the height of the lifting device 4 and the load applied to the lifting device 4 cannot be defined. In such cases, the relationship is stored using a function to calculate the tension (measured load Wl) of the load chain Cl of the hoisting machine 2 and a function to detect the unwinding length of the load chain Cl, and the information is stored in the transport control unit 5 or the robot control unit 30 (teaching).

[0086] (Teaching) The teaching operation is the process in which an operator manually moves the workpiece Wo from the start point to the end point of the lifting operation that the robot device 3 is to perform, by gripping the cylinder operating device 6, and measures the relationship between the position of the lifting device 4 and the vertical load, and stores the result in the robot device 3. At this time, the relationship between the position of the lifting device 4 and the measured load Wl measured by the load sensor 22a is stored in the robot device 3, and this relationship is stored as shown by the dashed line in Figure 6. With this, if the position of the lifting device 4 is known, the vertical load required to maintain that position can be derived.

[0087] For example, let's specifically describe the case where an operator grips the cylinder operating device 6 to teach the ground-lifting operation. The hoisting machine 2 is set to position control mode or switch control mode and operated. In position control mode or speed control mode, if necessary, the operator assists with the cylinder operating device 6 to wind up the load chain Cl from the start point to the end point of the ground-lifting operation, raising the lifting device 4. At this time, the hoisting machine 2 measures the measured load Wl in real time and stores the height of the lifting device 4 at that measured load Wl in association with it.

[0088] In this operation, the connection between the lifting device 4 and the hand unit 37a is released to perform the measurement work. However, if the robot device 3 can be set to a tracking mode or similar so that the connection of the robot device 3 does not affect the measurement of the measured load Wl by the hoisting machine 2, it is preferable from the standpoint of work efficiency to perform the measurement with the hand unit 37a still connected. In that case, the measured load Wl is transmitted and received in real time between the robot device 3 and the hoisting machine 2 via Ethernet. If teaching work can be performed with the hand unit 37a connected to the lifting device 4, the robot device 3 can record not only the height information of the lifting device 4 but also the trajectory of the lifting device 4 during the ground cutting process.

[0089] Because the workpiece Wo has an irregular shape, there are regions where the rate of increase of the measured load Wl is high due to changes in the height of the lifting device 4, and conversely, regions where the measured load Wl decreases while the height increases. Therefore, there is no regularity between the amount of rise of the workpiece Wo due to changes in the posture of the workpiece Wo and the amount of rise of the measured load Wl. This tendency is more pronounced when the workpiece Wo changes not only its posture but also its shape during ground cutting.

[0090] Therefore, although the measured load Wl changes irregularly in accordance with the change in height, the measured load Wl and the height of the lifting device 4 are always measured and stored. As a result, during subsequent automatic operation, if the height of the lifting device is known, the vertical load required to maintain that height, i.e., the specified load (set load Wl0), can be derived.

[0091] Subsequently, when actually performing ground cutting using automated operation, the measured load Wl, which changes according to the height of the lifting device 4 and was memorized through teaching operations, is instructed to the hoisting machine 2 as the specified load (set load Wl0). As a result, the relationship between the height of the lifting device 4 and the specified load (set load Wl0) is reproduced with almost accuracy through teaching operations performed in advance by the operator, and by moving the robot device 3 with position control, it is prevented from being subjected to excessive load even with complex workpieces Wo.

[0092] (implantation process) As shown in Figure 4D, when the workpiece transport system 10 lowers the workpiece Wo onto the work ground F and places it on the ground, the posture of the workpiece Wo may change as the lifting device 4 descends. In particular, as with the ground cutting described above, changes in posture are more likely to occur when the shape of the workpiece Wo is irregular.

[0093] If there is no change in the posture of the workpiece Wo, the hoisting machine 2 can be controlled in float mode by setting the load Wl0 to a set load (a sufficiently light load within the allowable load that the robot device 3 can hold) which is the total weight of the lifting device 4 and the workpiece Wo minus a predetermined load (a load that is sufficiently light within the allowable load that the robot device 3 can hold). However, if the posture of the workpiece Wo changes as the lifting device 4 descends, the load on the workpiece Wo on the lifting device 4 changes significantly, and the amount of change exceeds the allowable load of the robot device 3. The robot device 3 cannot control the posture of the workpiece Wo, and the hoisting machine 2's hoisting and lowering operation cannot keep up with the robot device 3's movement of the lifting device 4, which may cause the robot device 3 to stop.

[0094] For example, when the workpiece Wo is in contact with the work surface F just before the end of lowering, and then changes its posture as it is lowered, and the workpiece Wo is fully in contact with the ground when the lifting device 4 has descended to a predetermined height, the appropriate set load Wl0 will constantly change.

[0095] Thus, if the shape of the workpiece Wo causes a change in posture during landing, the robot device 3 is pre-programmed with a table to store the specified load (set load Wl0) that it instructs the hoisting machine 2 to change according to the position of the lifting device 4.

[0096] [Specific example] The series of operations of the workpiece transport system 10 will be explained with reference to the operation table in Figure 7 and the time chart in Figure 8.

[0097] Figure 7 is an operation table showing the operations performed by the workpiece transport system 10, divided into the robot device 3 and the hoisting machine 2. The vertical axis of the operation table is a code indicating the operations performed in chronological order from START to END. The horizontal axis of the operation table shows the robot control state, the hoisting machine operation mode, and the set load Wl0 of the hoisting machine 2.

[0098] Figure 8 is a time chart showing the set load Wl0 of the hoisting machine 2, which changes over time during a series of operations of the workpiece transport system 10. The horizontal axis of the time chart represents time, and the vertical axis represents the set load Wl0. The operating state of the workpiece transport system 10 is also noted along the time axis, and the time is indicated at the point where the operating state changes. In the explanation of the operation table below, the time on the corresponding time chart is indicated in parentheses.

[0099] The transport of the workpiece Wo by the workpiece transport system 10 is controlled by the transport control unit 5. In this series of operations, the transport control unit 5 outputs an automatic transport command signal to the hoisting machine control unit 20 and the robot control unit 30. The hoisting machine control unit 20 sets its control mode to the linked float mode, and the robot control unit 30 sets its control mode to the position control mode. In linked float mode, the hoisting machine control unit 20 reads the specified load information Wli output by the transport control unit 5 and overwrites and updates the set load Wl0.

[0100] When the robot device 3 is controlled to remain in the standby position, in step S11 the transport control unit 5 outputs specified load information Wli corresponding to the load of the lifting device 4, and the hoisting machine control unit 20 reads it and sets the set load Wl0. The transport control unit 5 instructs the robot control unit 30 to move the lifting device 4 to the ground clearance position (Figure 8 (0~t1)). At this time, since the hoisting machine 2 is in float mode, it exerts a hoisting force of torque command value Tm calculated from the measured load Wl and the set load Wl0, and the robot device 3 moves the lifting device 4 freely.

[0101] In step S12, the transport control unit 5 connects the lifting device 4 and the workpiece Wo to the robot device 3 (t1). In this state, the load of the workpiece Wo is not yet applied to the lifting device 4, and the set load Wl0 of the hoisting machine 2 is set to the load of the lifting device 4.

[0102] In step S13, the transport control unit 5 commands the robot device 3 to switch to the linked float mode and, while moving the lifting device 4 for the ground cutting operation, outputs specified load information Wli corresponding to the position of the lifting device 4 (t1~t2). The hoisting machine control unit 20 takes in the specified load information Wli, repeatedly updates the set load Wl0, calculates the torque command value Tm based on the latest measured load Wl and the latest set load Wl0, and commands the driver 29.

[0103] During the ground-cutting operation, the load on the lifting device 4 changes according to the position of the lifting device 4. Therefore, the transport control unit 5 transmits specified load information Wli to the hoisting machine control unit 20 based on the graphs shown in Figure 5B and Figure 6, according to the shape of the workpiece Wo. The transport control unit 5 outputs the load that it wants the hoisting machine 2 to bear according to the position of the lifting device 4 as specified load information Wli, and also commands the robot control unit 30 to move the lifting device 4 along a trajectory suitable for the ground-cutting operation.

[0104] In step S14, the transport control unit 5 determines whether the height of the lifting device 4 has reached the ground-clearing completion height. If the height of the lifting device 4 has reached the ground-clearing completion height (t2), the operation proceeds to step S15. If the height of the lifting device 4 has not reached the ground-clearing completion height, the operation proceeds to step S13, and the ground-clearing operation continues until the height of the lifting device 4 reaches the ground-clearing completion height.

[0105] In step S15, the transport control unit 5 commands the hoisting machine 2 to transfer the specified load information Wli and to switch to normal float mode, and the robot device 3 moves the workpiece Wo upwards to the landing position along the predetermined trajectory of the lifting device 4 (t2~t3). At this time, the set load Wl0 of the hoisting machine 2 is set based on the specified load information Wli. The hoisting machine control unit 20 calculates the torque command value Tm based on the measured load Wl and the set Wl0 and commands the driver 29.

[0106] Specifically, the specified load information Wli is set to the load obtained by adding the load of the workpiece Wo to the load of the lifting device 4. In this step S15, since the ground clearance is complete and the load of the workpiece Wo does not change according to the position of the lifting device 4, the update of the set load Wl0 by the specified load information Wli may be suspended. By suspending the update of the set load Wl0 and switching to normal float mode, the load on the hoisting machine control unit 20 is reduced, making it possible to respond to the movement of the lifting device 4 at a higher speed than in the coordinated float mode.

[0107] In step S16, the transport control unit 5 causes the robot device 3 to move the workpiece Wo to the position above the landing position (t3). At this point, the set load Wl0 of the hoisting machine 2 is the same as in step S15.

[0108] In step S17, the transport control unit 5 lowers the workpiece Wo from above the landing position (t3~t4). At this time, the set load Wl0 of the hoisting machine 2 is the same as in step S15.

[0109] In step S18, the transport control unit 5 commands the hoisting machine 2 to switch to the linked float mode, and while moving the lifting device 4 along a predetermined trajectory for landing, outputs specified load information Wli corresponding to the position of the lifting device 4. The hoisting machine control unit 20 receives the specified load information Wli and updates the set load Wl0. The hoisting machine control unit 20 calculates the torque command value Tm based on the latest measured load Wl and the latest set load Wl0, and commands the driver 29.

[0110] Accordingly, the hoisting machine 2 changes the force with which it hoists the lifting device 4 based on the specified load information output by the transport control unit 5, so that the workpiece Wo is brought to the ground (t3~t4) in accordance with the movement of the lifting device 4 moved by the robot device 3. The specified load information that the transport control unit 5 transmits to the hoisting machine control unit 20 is defined based on the graph shown in Figure 5B above or a graph stored for landing that is not shown. During the landing operation, the load on the lifting device 4 changes according to the position of the lifting device 4, so the load on the workpiece Wo added in this step S18 is set to gradually decrease according to the height of the workpiece Wo.

[0111] In step S19, the transport control unit 5 determines whether the height of the lifting device 4 is equal to the landing completion height. If the height of the lifting device 4 is equal to the landing completion height (t4), the operation proceeds to step S20. If the height of the lifting device 4 is not equal to the landing completion height, the operation proceeds to step S18, and the landing operation continues until the height of the lifting device 4 reaches the landing completion height.

[0112] In step S20, the transport control unit 5 completes the landing operation by placing the workpiece Wo on the work ground F (t4). Upon completion of landing, the workpiece Wo is released from the lifting device 4. The transport control unit 5 sends a command to the hoisting machine 2 to switch to normal float mode and the load of the lifting device 4 as specified load information Wli to the hoisting machine control unit 20. The set load Wl0 of the hoisting machine 2 is set to the load of the lifting device 4.

[0113] In step S21, the transport control unit 5 moves the lifting device 4 to the standby position, and the series of transport operations by the work transport system 10 is completed (t5). In either the coordinated float mode or the normal float mode, if the hoisting machine 2 attempts to raise or lower the lifting device 4 too far relative to the robot device 3, the hoisting machine control unit 20 can detect this as an operating force Ws and prevent it from being raised or lowered too far.

[0114] In steps where the reference load (set load Wl0) borne by the hoisting machine 2 does not change with the height of the lifting device 4, the hoisting machine 2 is set to operate in normal float mode, which has a low control load, but it may also be set to operate in coordinated float mode.

[0115] [Differentiation] In the above embodiment, the robot device 3 is fixed to the work surface F, but it may also be mounted on a crane or a trolley that can move horizontally on the floor, and the crane or trolley may be driven and controlled as an external axis. This expands the range that the robot device 3 can transport.

[0116] Furthermore, although the above embodiment illustrates a multi-joint robot as the robot device 3, any other robot or automated transport device capable of transporting the lifting device 4 in three dimensions may be used.

[0117] Furthermore, in the above embodiment, the hoisting machine 2 employs a winding mechanism consisting of a load chain Cl and a load sheave 25, but it may also be a winding mechanism consisting of a rope or belt (not shown) and a winding drum. In this case, the wound rope or belt is held by the winding drum, so the chain bucket 24 is unnecessary.

[0118] Furthermore, in the above embodiment, the load sensor 22a is a load cell equipped with a strain gauge, but a crane scale or the like may be used as long as it has the accuracy and responsiveness suitable for torque control.

[0119] Furthermore, the drive motor 26 in the above embodiment may be a combination of an induction motor, an encoder, and a vector control inverter control device, or it may be any other configuration, as long as torque control is possible.

[0120] Furthermore, the hoisting machine 2 may have its hoisting machine control unit 20 and driver 29 located on the running rail 11, separate from the hoisting machine body 22, in order to make the hoisting machine body 22 smaller and lighter.

[0121] Furthermore, in the above embodiment, the workpiece Wo is suspended from a connector 42 provided on the lower surface of the connecting member 41 of the lifting device 4. However, instead of the connector 42, the lower surface of the connecting member 41 may have an adsorption part for adsorbing the workpiece Wo, and the workpiece Wo may be adsorbed by a lifting magnet, vacuum pad, or the like as the adsorption part.

[0122] Furthermore, in the above embodiment, the lifting device 4 is suspended from the lower hook 21 of the hoisting machine 2, but the lower hook 21 can be replaced with a connector 42 for the lifting device 4. In that case, it is preferable that the hand portion 37a of the robot device 3 grips the upper part of the lower hook 21.

[0123] Furthermore, in the above embodiment, the hoisting machine 2 and the robot device 3 are connected by Ethernet IP communication, but other communication methods may be used as long as the hoisting machine 2 and the robot device 3 can communicate with each other.

[0124] Furthermore, in the above embodiment, the hoisting machine control unit 20 updates the set load Wl0 by receiving specified load information Wli from the transport control unit 5 based on the position of the lifting device 4. However, the set load Wl0 may also be updated based on position information from the transport control unit 5, or height information (chain payout length information) of the lower hook 21 detected by the hoisting machine control unit, and position and load information stored in advance for each type of workpiece Wo for each ground cutting process or landing process.

[0125] Furthermore, the horizontal movement mechanism of crane 1 is equipped with a driven traveling trolley and a traversing trolley that do not require power, but it may also be equipped with a power mechanism that allows for position control and is controlled by the robot control unit 30 or the transport control unit 5 as an external axis of the robot device 3.

[0126] Furthermore, in the above embodiment, examples of how the tension on the load chain Cl changes while the workpiece transport system is transporting the workpiece Wo are shown at the time of lifting and landing. However, if the workpiece Wo is a container, the tension also changes (decreases) in the process of tilting the workpiece Wo to transfer its contents to another container (tilting process) as the contents change (decrease). At this time, the robot device 3 tilts the workpiece Wo by changing the posture of the lifting device 4. Therefore, the position information of the lifting device 4 may conceptually include posture information of the lifting device 4.

[0127] [Supplementary explanation of the embodiment] The embodiments described above are all preferred examples of the present invention. The numerical values, arrangement positions of components, and connection configurations shown in the embodiments above are examples only and are not intended to limit the present invention. Furthermore, the figures are not necessarily strictly illustrative.

[0128] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0129] The series of processes described above can be executed by hardware or by software. When the series of processes are executed by software, the programs that make up the software are installed from a program storage medium on a computer that is built into dedicated hardware, or on a general-purpose computer that can perform various functions by installing various programs.

[0130] The programs executed by the computer may be programs that are processed chronologically in the order described herein, or they may be programs that are processed in parallel or at necessary times, such as when a call is made.

[0131] [Note] The contents described in some of the embodiments above can be understood, for example, as follows:

[0132] (1) Set load is height dependent (specified load information from the transport control unit) A hoisting machine 2 raises and lowers the workpiece Wo by winding up and down the load chain Cl, A lifting device 4 is connected to the lower end of the load chain Cl and engages with and suspends the workpiece Wo, A robotic device 3 connected to the lifting device 4 and moving the lifting device 4, As the lifting device 4 is moved by the robotic device 3, the crane 1 moves the hoisting machine 2 to follow so that it is positioned directly above the lifting device 4. A transport control unit 5 that coordinates the operation of the robot device 3 and the hoisting machine 2, A workpiece transport system 10 comprising, Hoisting machine 2 is, A load sheave 25 that raises and lowers the load chain Cl, A drive motor 26 generates a driving force to rotate the load sheave 25, A load calculation unit 20b calculates the tension (measured load Wl) applied to the load chain Cl, A float calculation unit 20c controls the torque of the drive motor 26 based on the tension (measured load Wl) and the reference load (set load Wl0), using the specified load information Wli instructed from the transport control unit 5 or the robot device 3 as the reference load (set load Wl0). Equipped with, When transporting the workpiece Wo in a predetermined process, the transport control unit 5 or the robot device 3 changes the specified load information Wli according to the predetermined process and the position of the lifting device 4.

[0133] As a result, when transporting the workpiece Wo in a predetermined process, the vertical load borne by the hoisting machine 2 is optimally changed according to the position of the lifting device 4, so that even if the workpiece Wo has a shape that causes changes in posture, the workpiece Wo can be transported without a large load acting on the robot device 3. The robot device 3 can instruct the hoisting machine 2 to bear a specified load information Wli, taking into account not only the position information of the lifting device 4 but also other information.

[0134] (2) Set load is dependent on height (conveying process information) A hoisting machine 2 raises and lowers the workpiece Wo by winding up and down the load chain Cl, A lifting device 4 is connected to the lower end of the load chain Cl and engages with and suspends the workpiece Wo, A robotic device 3 connected to the lifting device 4 and moving the lifting device 4, As the lifting device 4 is moved by the robotic device 3, the crane 1 moves the hoisting machine 2 to follow so that it is positioned directly above the lifting device 4. A transport control unit 5 that coordinates the operation of the robot device 3 and the hoisting machine 2, A workpiece transport system 10 comprising, Hoisting machine 2 is, A load sheave 25 that raises and lowers the load chain Cl, A drive motor 26 generates a driving force to rotate the load sheave 25, A load calculation unit 20b calculates the tension (measured load Wl) applied to the load chain Cl, A float calculation unit 20c controls the torque of the drive motor 26 based on a standard load (set load Wl0) defined for each workpiece Wo and the tension applied to the load chain Cl (measured load Wl), Equipped with, When transporting the workpiece Wo in a predetermined process, the reference load (set load Wl0) is changed according to the predetermined process and the position of the lifting device 4.

[0135] As a result, when transporting the workpiece Wo in a predetermined process, the vertical load borne by the hoisting machine 2 is optimally changed according to the position or orientation of the lifting device 4, so that even if the workpiece Wo has a shape that causes changes in orientation during transport, the workpiece Wo can be transported without a large load acting on the robot device 3. The height position of the lifting device 4 is detected by the hoisting machine 2 using the unwinding length of the load chain Cl, thus avoiding communication delay problems.

[0136] (3) Torque command value Tm The float calculation unit 20c can calculate the torque command value Tm from the reference load (set load Wl0) and the operating force Ws, which is the difference between the reference load (set load Wl0) and the tension (measured load Wl).

[0137] This allows the hoisting machine 2 to accurately assist the vertical load on the robot device 3 via the lifting device 4 without complicating the signals transmitted and received between the hoisting machine control unit 20 and the robot control unit 30.

[0138] (4) Predetermined process The predetermined process may be at least one of the following processes: a workpiece cutting process, a workpiece placement process, or a workpiece tilting process.

[0139] As a result, even when lifting and lowering a workpiece Wo whose shape causes a change in posture, such as lifting it off the work surface F or platform, landing it on the work surface F or platform, or tilting the workpiece Wo to transfer its contents to another container, the hoisting machine 2 optimally changes the vertical load borne by the hoisting machine 2 according to the position of the lifting device 4, so that the workpiece Wo can be lifted off the ground, landed on, and tilted without a large load acting on the robot device 3. The height position of the lifting device 4 is detected by the hoisting machine 2 using the payout length of the load chain Cl, thus avoiding communication delay problems.

[0140] (5) Modelable If the relationship between the position of the lifting device 4 and the tension applied to the load chain Cl can be defined by a predetermined calculation based on the shape of the workpiece Wo, the tension applied to the load chain Cl calculated based on the position of the lifting device 4 when lifting the workpiece Wo can be instructed to the float calculation unit 20c as the reference load (set load Wl0).

[0141] This means that if the relationship between the position of the lifting device 4 and the tension on the load chain Cl can be defined by a table or the like based on the shape of the workpiece Wo, then even if the load changes depending on the height of the lifting device 4, the load to be borne by the hoisting machine 2 can be determined if the height of the lifting device 4 is known, thereby suppressing the load placed on the robot device 3.

[0142] (6) Not modelable The transport control unit 5 stores in advance the increase or decrease in tension on the load chain Cl according to the position of the lifting device 4 when the workpiece Wo placed on the work surface F or the mounting area is raised by the hoisting machine 2 from the start point to the end point of the lifting, as a stored reference load, and can instruct the float calculation unit 20c to use the stored reference load corresponding to the current height of the lifting device 4 as the reference load.

[0143] This allows the robotic device 3 to remember the relationship between the position of the lifting device 4 and the tension on the load chain Cl (measured load Wl) when the workpiece Wo has a complex shape and it is difficult to define the relationship between the height of the lifting device 4 and the tension on the load chain Cl (measured load Wl) when the operator performs a lifting motion of the workpiece Wo to teach it to the robotic device 3. Therefore, if the position of the lifting device 4 is known, the load to be borne by the hoisting machine 2 can be determined, and the load on the robotic device 3 can be suppressed.

[0144] (7) Implantation When the workpiece Wo is lowered, the reference load (set load Wl0) can be set to gradually decrease as the workpiece Wo descends.

[0145] This allows the set load Wl0 to change as the workpiece Wo is gradually lowered, enabling the workpiece Wo to be lowered and brought to a rest in float mode. [Explanation of Symbols]

[0146] 1 Crane 2 Hoisting machine 3. Robot equipment 4. Lifting device 5. Transport Control Unit 10 Workpiece Transfer System 20b Load calculation section 20c Float calculation unit (motor control unit) 22 Hoisting machine body 25 Load sheave (winding section) 26 Drive motor Cl Load chain (chain or linear member) Wo Work

Claims

1. A hoisting machine that raises and lowers a workpiece by winding up and down a chain or linear member, A suspension device connected to the lower end of the chain or the linear member and attached to and suspended from the workpiece, A robotic device connected to the aforementioned lifting device and used to move the lifting device, A crane moves the hoisting machine to follow the movement of the lifting device by the robotic device so that it is positioned directly above the lifting device, A transport control unit that coordinates the operation of the robot device and the hoisting machine, A workpiece transport system comprising, The aforementioned hoisting machine is, A winding section for winding up and down the chain or the linear member, A drive motor that generates a driving force to rotate the winding portion, A load calculation unit that calculates the tension applied to the chain or the linear member, A motor control unit controls the torque of the drive motor based on the tension and the reference load, with the specified load instructed by the transport control unit or the robot device as the reference load. Equipped with, When transporting the workpiece in a predetermined process, the transport control unit or the robotic device changes the specified load according to the predetermined process and the position of the lifting device. A workpiece transport system characterized by the following features.

2. A hoisting machine that raises and lowers a workpiece by winding up and down a chain or linear member, A suspension device connected to the lower end of the chain or the linear member and attached to and suspended from the workpiece, A robotic device connected to the aforementioned lifting device and used to move the lifting device, A crane moves the hoisting machine to follow the movement of the lifting device by the robotic device so that it is positioned directly above the lifting device, A transport control unit that coordinates the operation of the robot device and the hoisting machine, A workpiece transport system comprising, The aforementioned hoisting machine is, A winding section for winding up and down the chain or the linear member, A drive motor that generates a driving force to rotate the winding portion, A load calculation unit that calculates the tension applied to the chain or the linear member, A motor control unit that controls the torque of the drive motor based on a reference load and tension defined for each workpiece, Equipped with, When transporting the workpiece in a predetermined process, the reference load is changed according to the predetermined process and the position of the lifting device. A workpiece transport system characterized by the following features.

3. A workpiece transport system according to claim 1 or 2, The motor control unit determines the reference load and the difference between the reference load and the tension, The torque command value output by the drive motor is calculated from this. A workpiece transport system characterized by the following features.

4. A workpiece transport system according to claim 1 or 2, The predetermined process is at least one of the following processes: a workpiece cutting process, a workpiece placement process, and a workpiece tilting process. A workpiece transport system characterized by the following features.

5. A workpiece transport system according to claim 4, If the relationship between the position of the lifting device and the tension applied to the chain or linear member can be defined by a predetermined calculation based on the shape of the workpiece, the motor control unit is instructed to use the tension applied to the chain or linear member, calculated based on the position of the lifting device, as the reference load when lifting the workpiece. A workpiece transport system characterized by the following features.

6. A workpiece transport system according to claim 4, The transport control unit stores in advance, as a reference load, the increase or decrease in tension on the chain or linear member according to the position of the lifting device when the workpiece placed on the mounting section is raised by the hoisting machine from the starting point to the end point of the lifting, and instructs the motor control unit to use the currently stored reference load corresponding to the position of the lifting device as the reference load. A workpiece transport system characterized by the following features.

7. A workpiece transport system according to claim 4, When the workpiece is placed on the ground, the reference load is set to gradually decrease as the workpiece descends. A workpiece transport system characterized by the following features.

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