Hoist system and method for controlling hoist system

Abstract

Provided is a hoist system with which it is possible to control a workpiece to an orientation that is preferred by an operator without aggregating force that requires high-speed communication and high-speed processing. A motor control means of a hoist system 1 is capable of performing control driving in a float mode for driving a drive motor 40 on the basis of a first torque command value obtained by adding assist torque for assisting operation force to load torque that is balanced with a workpiece W. The motor control means is provided with an orientation controller 207 that determines a reference movement amount on the basis of movement amounts in a plurality of hoists 10, and calculates orientation control torque for performing orientation control of the workpiece W on the basis of an orientation deviation between the reference movement amount and the current position of a connection portion of the workpiece W. The motor control means is capable of performing orientation control for performing orientation control of the workpiece W in the float mode. In the orientation control, the motor control means controls driving of the drive motor 40 on the basis of a second torque command value obtained by adding the orientation control torque to the first torque command value.

Description

Hoisting machine system and control method for hoisting machine system

[0001] The present invention relates to a hoisting machine system and a control method for a hoisting machine system.

[0002] Among hoists known as "balancers," there is a type in which the operator of the hoist controls the hoisting by measuring the force (external force) applied to the lifted workpiece in the desired direction of lifting, without using an operation switch to command hoisting or lowering. Patent Document 1, for example, discloses a technology for using multiple such hoists to lift and lower a large workpiece.

[0003] In Patent Document 1, in order to maintain the posture of a workpiece lifted by multiple hoists, a force target calculation means calculates a force target value for each hoist based on the sum of the forces exerted by the workpiece on the force measurement means provided in each hoist. Then, a first control reference value is calculated from the force target value and each force measurement value by a force control means, a position target calculation means calculates a position reference value, and a second control reference value is calculated from the position target value and the position of each object by a position control means. These first and second control reference values ​​are calculated by a control command output means, and a control command signal is output to the drive means of each motor for control.

[0004] Patent No. 6695134

[0005] However, in the configuration shown in Patent Document 1, in order to aggregate the forces measured by each measuring means in multiple hoists, calculate the force target value, and control the force, high-speed communication and high-speed processing are required between the hoists.

[0006] For this reason, in Patent Document 1, in a control mode in which the force applied to the workpiece by the worker operating the hoist is detected and hoisting control is performed without using an operating switch to operate the hoist, smooth force control cannot be achieved or a time lag will occur between the worker's intentions and the operation of the hoist, unless communication for tallying up the forces measured by each hoist and calculation of the force target value based on the force tally are performed at high speed in accordance with the calculation cycle for force control in that control mode.

[0007] In addition, in Patent Document 1, it is possible to apply an external force to the workpiece to move it up and down while the workpiece is maintained in a horizontal or oblique position. However, for example, when inserting holes in the workpiece into an external shaft, it may be easier to first insert the shaft into some holes for positioning purposes, and then insert the shaft into other holes. In such an operation, the workpiece may be slightly tilted from a horizontal position to lower only certain holes in the workpiece relative to the other holes. However, the technology disclosed in Patent Document 1 is not suitable for such a case.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a hoist system and a control method for a hoist system that can control the workpiece to assume a posture that is preferable for the worker, without tallying up forces that require high-speed communication and high-speed processing between each hoist.

[0009] In order to solve the above problems, according to a first aspect of the present invention, there is provided a hoisting machine system which includes a plurality of hoists and which raises and lowers a workpiece by winding up and down a load chain or rope of each hoist, and which includes: a hoisting means which is arranged on the hoisting machine body, has a load chain or rope wound around it, and which winds up and lowers the load chain or rope in response to rotation of the hoisting machine; a drive motor which generates a driving force to rotate the hoisting means; a motor control means which controls the drive of the drive motor; a load detection means which detects the tension of the load chain or rope and the operating force applied to the load chain or rope when an operator operates the workpiece in the winding up and winding down direction; and a position detection means which detects the position of the load chain or rope. The motor control means is capable of controlled driving in a torque control mode in which the drive motor is driven based on a first torque command value obtained by adding an assist torque that assists the operating force to a holding torque that can maintain tension, and the motor control means is equipped with a posture control unit that calculates its own movement amount from the position detected by the position detection means, transmits its own movement amount to another hoist, determines a reference movement amount based on its own movement amount and the received movement amount of the other hoist, and calculates a posture control torque value for controlling the posture of the work based on the difference between the reference movement amount and its own movement amount, and the motor control means controls the posture of the work in the torque control mode by controlling the drive of the drive motor based on a second torque command value obtained by adding the posture control torque value to the first torque command value.

[0010] Further, in order to solve the above-mentioned problems, according to a second aspect of the present invention, there is provided a control method for a hoisting machine system which includes a plurality of hoists and which raises and lowers a workpiece by winding up and down a load chain or rope of each hoist, wherein each hoist is arranged on the main body of the hoisting machine, has a load chain or rope wound therearound, and comprises hoisting means which winds up and lowers the load chain or rope in response to rotation of the hoisting machine, a drive motor which generates a driving force for rotating the hoisting means, motor control means which controls the drive of the drive motor, load detection means which detects the tension of the load chain or rope and the operating force applied to the load chain or rope by an operator operating the workpiece in the hoisting / lowering direction, and position detection means which detects the position of the load chain or rope, and the motor control means detects the tension of the load chain or rope. The present invention provides a control method for a hoist system, characterized in that the method is capable of controlled driving in a torque control mode in which the drive motor is driven based on a first torque command value obtained by adding an assist torque that assists the operating force to a holding torque that is capable of holding a force, and that the method performs attitude control to control the attitude of the work in the torque control mode, and that the attitude control includes a movement amount calculation step in which the movement amount is calculated from the position detected by the position detection means, a reference movement amount determination step in which the movement amount is transmitted to another hoist and a reference movement amount is determined, an attitude deviation calculation step in which the difference between the reference movement amount and the hoist's own movement amount is calculated, an attitude control torque calculation step in which an attitude control torque for controlling the attitude of the work is calculated based on the difference, and a drive control step in which the attitude control torque is controlled to drive the drive motor based on a second torque command value obtained by adding the attitude control torque to the first torque command value.

[0011] According to the present invention, it is possible to provide a hoist system and a control method for a hoist system that can control the workpiece to be in a posture that is preferable for the worker, without tallying up forces that require high-speed communication and high-speed processing between each hoist.

[0012] 1 is a schematic diagram showing the overall configuration of a hoist system according to an embodiment of the present invention. FIG. 1 is a diagram showing the overall control configuration of a hoist that constitutes the hoist system shown in FIG. 1. FIG. 2 is a diagram showing the configuration of a cylinder operating device for the hoist in the hoist system shown in FIG. 1. FIG. 3 is a diagram showing the configuration of an operation switch used in the hoist system shown in FIG. 1. FIG. 4 is a diagram for explaining the functional configuration of an attitude control unit provided in a control unit of the hoist system shown in FIG. 1. FIG. 5 is a diagram showing a part of the control flow of the hoist in the hoist system shown in FIG. 1, showing steps S01 to S10. FIG. 6 is a diagram showing a part of the control flow of the hoist in the hoist system shown in FIG. 1, showing steps S11 to S15. FIG. 7 is a diagram showing steps S16 to S23 of the hoist in the hoist system shown in FIG. 1. FIG. 8 is a diagram showing steps S24 to S33 of the hoist in the hoist system shown in FIG. 1. FIG. 9 is a diagram showing steps S40 to S50 of the hoist in the hoist system shown in FIG. 1. 2A and 2B are diagrams showing the relationship between speed and position in an upper speed deceleration region or an upper speed deceleration region in the hoist of the hoist system shown in Fig. 1. Fig. 2A is a diagram showing the relationship between a torque command value and position in the hoist of the hoist system shown in Fig. 1, where (A) shows a state in which a force is applied in the lifting direction in the upper damping region, and (B) shows a state in which a force is applied in the push-down direction in the lower damping region.

[0013] Hereinafter, a hoist system 1 according to an embodiment of the present invention and a control method for a hoist 10 constituting the hoist system 1 (control method for the hoist system 1) will be described with reference to the drawings.

[0014] [1. Configuration of hoisting machine system 1] Fig. 1 is a schematic diagram showing the overall configuration of the hoisting machine system 1. Fig. 2 is a diagram showing the schematic configuration of a hoist 10 that constitutes the hoisting machine system 1. As shown in Fig. 1, in this embodiment, the hoisting machine system 1 is provided with three hoists 10, and these three hoists 10 work in conjunction or in cooperation with each other to lift a large workpiece W at different positions on the workpiece W with a load chain C1, thereby controlling the posture of the workpiece W and raising and lowering it. The hoists 10 are connected by a signal line. The number of hoists 10 is not limited to three, and may be two or more.

[0015] In the following description, when it is necessary to distinguish between the three hoists 10, they will be referred to as hoists 10A, 10B, and 10C, but when it is not necessary to distinguish between the hoists 10A to 10C, for example, when describing a common configuration, they will simply be referred to as hoist 10.

[0016] 2, each of the hoisting machines 10 (10A to 10C) has a hoisting machine main body 20, an upper hook 30, a cylinder operating device 150, and a chain bucket 170 that stores the wound-up load chain C1. Furthermore, to improve operability, an operating switch 180 is also provided separately from the cylinder operating device 150.

[0017] The hoisting machine main body 20 can be suspended from a trolley of an overhead crane (not shown) or the like via the upper hook 30, and can be moved by a horizontal movement device such as an overhead crane to above a portion where a lower hook 160 (described later) is connected to a workpiece W so that the load chain C1 extends substantially vertically. The hoisting machine main body 20 accommodates various components inside a housing 21. Specifically, the housing 21 is provided with a drive motor 40, a speed reduction mechanism 50, a brake mechanism 60, a load sheave 70 that winds up the load chain C1, an upper limit switch 80, a lower limit switch 81, a load sensor 90, a control unit 100, a driver 110, and a transceiver unit 120.

[0018] It should be noted that a hoist body consisting of a rope and a take-up drum (not shown) can be used instead of the load chain C1 and the load sheave 70. In this case, the taken-up rope is held by the take-up drum, so the chain bucket 170 is not required.

[0019] The drive motor 40 is a motor that provides a driving force to drive the load sheave 70. In this embodiment, the drive motor 40 is a servomotor equipped with a detector (encoder 41) for detecting a position (the rotational position of a rotor, not shown), and is preferably an AC servomotor. Note that a synchronous motor is preferable as the AC servomotor, but an induction motor may also be used.

[0020] The reduction mechanism 50 is a part that reduces the speed of the rotation of the drive motor 40 and transmits it to the load sheave 70. The brake mechanism 60 is a part that can release the braking force by electromagnetic force when the drive motor 40 is operating, but is also a part that generates braking force so as to hold the load of the workpiece W even when the drive motor 40 is not operating.

[0021] The load sheave 70 is the part that winds up and down the load chain C1, and is provided with a plurality of chain pockets along its outer periphery into which the metal rings of the load chain C1 fit. The load chain C1 corresponds to the load chain or rope, and the load sheave 70 corresponds to the hoisting means.

[0022] The upper limit switch 80 is a switch for detecting the limit position (mechanically and structurally set upper limit position) for winding up the load chain C1, and the lower limit switch 81 is a switch for detecting the limit position (mechanically and structurally set lower limit position) for winding down (releasing out) the load chain C1.

[0023] The load sensor 90 is a load sensor that measures the load applied to the portion connecting the upper hook 30 and the hoisting machine main body 20. The load sensor 90 is attached to, for example, a mounting shaft for attaching the upper hook 30 to the hoisting machine main body 20.

[0024] A load cell equipped with a strain gauge can be used as the load sensor 90. The load sensor 90 may be disposed at any position other than those described above, such as between the upper hook 30 and the crane trolley, between the lower hook 160 and the workpiece W, or between the end of the load chain C1 and the lower hook 160, as long as it is configured to detect the information required to calculate the tension applied to the load chain C1 suspending the workpiece W and output it to the control unit 100. The load sensor 90, or the load sensor 90 and a part of the function of the control unit 100 (such as the tension calculation unit 103) that calculates the tension of the load chain C1 applied to the load sheave 70 from the signal from the load sensor 90, corresponds to the load detection means.

[0025] Furthermore, the load sensor 90 can be a load cell or a crane scale placed between the lower hook 160 and the workpiece W to directly measure tension, but it must have the accuracy and responsiveness to output the measurement results to the control unit 100 and be usable for torque control of the hoist 10. Furthermore, the load sensor 90 can replace a measuring means for measuring the torque of the shaft that transmits torque between the load sheave 70 and the drive motor 40, or a motor load calculation means for calculating electric motor load information that is provided in a power conversion device such as a driver 110 that outputs drive power to the drive motor.

[0026] The control unit 100 is a part that provides the driver 110 with command values ​​for the control mode (speed control mode, torque control mode), position, speed, torque, etc. The control unit 100 and the driver 110 correspond to a motor control means. The control unit 100 may be, for example, a computer equipped with a CPU (Central Processing Unit), memory 101 (RAM (Random Access Memory), ROM (Read Only Memory), internal storage, external storage device, etc.), input / output interface, etc. The memory 101 stores a control program for operating in a switch operation mode and a float mode, which will be described later.

[0027] In the float mode, it is also possible to perform posture control, as will be described later, when controlling a plurality of hoists 10, such as three hoists 10, in an interlocked or cooperative manner. In order to perform such posture control, the control unit 100 also has the functionality of a posture control unit 200, as will be described later, and the posture control unit 200 will be described in detail later.

[0028] Furthermore, the control unit 100 reads out the control program stored in the memory 101 and executes it using a CPU or the like, thereby functionally realizing a position calculation unit 102, a tension calculation unit 103, and a torque command calculation unit 104, and further functionally realizing an attitude control unit 200 and an inertia moment calculation unit 220, which will be described later.

[0029] The position calculation unit 102 calculates the payout length of the load chain C1 based on the output signal of the encoder 41, and calculates the current position L1 of the connection portion of the workpiece W to which the lower hook 160 is connected, and the posture control start position L1s. The position calculation unit 102 can also calculate the payout speed and acceleration of the load chain C1. This speed and acceleration become the lifting speed and acceleration of the connection portion of the workpiece W.

[0030] The tension calculation unit 103 calculates the tension (load w to be hoisted) applied to the load chain C1 based on the detection value of the load sensor 90 described above.

[0031] The inertia moment value 221 is a value stored in the memory 101 using the inertia moment J1 of the hoist 10 itself as a parameter. Note that the inertia moment value of the hoist 10 itself here refers to the value of the inertia moment of the mechanical parts that constitute the hoist 10 and that are driven by the drive motor 40, such as the drive motor 40 and gears.

[0032] Here, the "float mode" refers to torque control in which a torque command is output to the driver 110, which drives the drive motor 40, based on a tension value calculated by the tension calculation unit 103 based on the detection value of the load sensor 90, to perform torque control for each hoisting machine 10. Therefore, when an operator operating the hoisting machine 10 pushes the workpiece W up or down in the hoisting or lowering direction, for example by gripping the workpiece W with his or her hand, the output value w of the tension calculation unit 103 fluctuates. The control unit 100 determines the operator's intention (command) by comparing the output value (load to be hoisted) w with a reference value (set load to be hoisted) w0, and performs hoisting control as if the workpiece W follows the operator's intention. Therefore, the operator can raise or lower the workpiece W with the assistance of the drive of each hoisting machine 10 (drive motor 40) without using other command means such as a switch or voice. The float mode is a torque control mode based on an operating force command and corresponds to the torque control mode.

[0033] The reference value (set load to be hoisted) w0 is a value calculated and stored in memory 101 at the start of the float mode in order to execute the float mode. When no operating force Ws is applied to the workpiece W, the reference value (set load to be hoisted) w0 matches the tension of the load chain C1 applied to the load sheave 70. The reference value (set load to be hoisted) w0 and the output value (load to be hoisted) w correspond to tension.

[0034] The driver 110 controls the externally supplied power to an appropriate level based on the current value of the drive motor 40, the output of the encoder 41, and motor drive control command values ​​provided by the control unit 100, and supplies that power to the drive motor 40 to rotate it. Based on the output signal from the encoder 41, the driver 110 outputs position information corresponding to the payout length of the load chain C1 to the control unit 100. In this embodiment, since the drive motor 40 is a servo motor, the driver 110 is a servo driver with a speed control mode and a torque control mode, and selectively performs speed control or torque control based on commands from the control unit 100. However, the driver 110 may have only a torque control function, or may have both a position control function and a torque control function. The control unit 100 may calculate the payout length of the load chain C1 from the output signal from the encoder 41 and then calculate the position information of the lower end of the load chain C1.

[0035] The encoder 41 corresponds to the position detection means, and the payout length of the load chain C1 and the position information of the lower end of the load chain C1 correspond to the position of the load chain or rope.

[0036] The transmitter / receiver 120 is a part for transmitting and receiving information between a plurality of hoists 10, for example, three hoists 10. The transmitter / receiver 120 enables the exchange of information with other hoists 10, for example, by wire or wirelessly. This information includes information necessary for posture control, such as a movement amount L1d (described later) calculated from the payout length L1 of the load chain C1 calculated from the output signal of the encoder 41 detected in each of the hoists 10, movement amounts L2d to Lid of the other hoists 10 received from the other hoists 10, and an operation mode switching signal, as well as an emergency stop signal, various status signals, and other control information.

[0037] The cylinder operating device 150 is an operating device that is held by the operator's hand and is connected to the lower end of the load chain C1. A lower hook 160 is connected to the cylinder operating device 150 for suspending the workpiece W at a predetermined connecting portion. Figure 3 is a diagram showing the configuration of the cylinder operating device 150. As shown in Figure 3, the cylinder operating device 150 includes an operation mode selector switch 151, a movable grip 152, and a displacement sensor 153.

[0038] The operating device is not limited to an operating device connected to the lower hook 160, but may be an operating device (pendant switch) suspended by a cable from the main body of the hoist, or may be a wireless remote control device such as the operating switch 180 described below.

[0039] The operation mode selector switch 151 is a switch for switching the operation mode of the drive motor 40, and a switch signal of the operation mode selector switch 151 is output to the control unit 100. In this embodiment, there are at least two operation modes: a switch operation mode and a float mode. By pressing the operation mode selector switch 151, the control unit 100 can switch the operation mode of the drive motor 40 between the switch operation mode, the float mode, or another mode. In the switch operation mode, the control unit 100 outputs a speed control command to the driver 110 (servo driver) in response to an operation command from the operating device, and in the float mode, the control unit 100 outputs a torque control command to control the drive motor 40 by torque control in response to a value detected by the load detection means. The float modes preferably include a single-acting float mode and an attitude control float mode.

[0040] In addition, by performing a predetermined operation, such as pressing and holding the operation mode changeover switch 151 of one of multiple hoists 10 (e.g., three hoists), the multiple hoists 10 may be switched to a linked mode in which the multiple hoists 10 are linked together, as described in the operation flow described below.

[0041] The movable grip 152 is the part that is operated when operating in the switch operation mode. The movable grip 152 is provided so as to be slidable in the vertical direction and is held in a neutral position by a biasing means such as a spring. The movable grip 152 can be slid upward or downward from the neutral position against the biasing means. The displacement sensor 153 outputs a detection signal corresponding to the amount of sliding to the control unit 100. The control unit 100 then controls the speed of the drive motor 40 based on the detection signal. The cylinder operating device 150 corresponds to the operating device.

[0042] The chain bucket 170 is a part that stores and holds the unloaded (already wound) load chain C1 that is located on the opposite side of the load sheave 70 from the lower hook 160.

[0043] The hoist system 1 of this embodiment also has an operation switch 180 as shown in Fig. 4. Note that there are operation switches 180 for both the parent machine and the child machine, but in this embodiment, the parent machine and the child machine have a common configuration. However, the operation switch 180 for the parent machine and the operation switch 180 for the child machine may have different configurations.

[0044] The operation switch 180 includes a winding switch 181 , a winding down switch 182 , a mode changeover switch 183 , and a stop switch 184 .

[0045] The hoisting switch 181 is a switch for causing the hoisting machine 10 to perform a hoisting operation. The lowering switch 182 is a switch for causing the hoisting machine 10 to perform a lowering operation. The mode changeover switch 183 is a switch for changing the operation mode of the hoisting machine 10 between a switch operation mode and a float mode by being pressed. The stop switch 184 is a switch for stopping the operation of the hoisting machine 10.

[0046] The hoisting switch 181 and the hoisting switch 182 are basically for single-acting operation of the hoisting machine 10, but may be provided with an additional function for collectively interlocking operation of the other hoists 10 in the hoisting machine system 1. In addition, in a hoisting machine system 1 having a plurality of hoists 10, the float mode is basically the attitude control float mode, but it is preferable to be able to switch between the attitude control float mode and the single-acting float mode.

[0047] [3. Details of the posture control unit 200 of the hoist 10] Next, details of the posture control unit 200 that is functionally realized by the control unit 100 of the hoist 10 will be described. Fig. 5 is a diagram for explaining the functional configuration of the posture control unit 200. As shown in Fig. 5, the posture control unit 200 functionally realizes a first summing point 201, a first pull-out point 202, a reference movement amount determining unit 203, a second summing point 204, a total moment of inertia estimating unit 205, a posture control torque gain adjusting unit 206, and a posture controller 207.

[0048] In the following description, the values ​​L1, L1s, L1d, L1b, L1a, W1, J1, etc. are used in relation to the first hoisting machine 10A unless otherwise specified. However, in the ith hoisting machine 10, these various values ​​are Li, Lis, Lid, Lib, Lia, Wi, Ji, etc.

[0049] The first summing point 201 receives the current position L1 and the posture control start position L1s calculated by the position calculation unit 102 as input, and calculates the movement amount L1d from these. The reference posture of the workpiece W can be determined from each posture control start position L(1 to i)s. By winding up and winding down each load chain C1 the same distance from each posture control start position L(1 to i)s, the posture of the workpiece W can be matched with the reference posture. In other words, the posture of the workpiece W can be controlled by controlling the movement amount L(1 to i)d from each posture control start position L(1 to i)s so that it matches the reference movement amount L0d.

[0050] The first lead-out point 202 outputs the movement amount L1d to the reference movement amount determination unit 203 and also to the second addition point 204. The first lead-out point 202 also outputs the movement amount L1d to the reference movement amount determination unit 203 of the other hoists 10 in addition to its own reference movement amount determination unit 203. The hoist system 1 shown in FIG. 5 shows a configuration including two hoists 10. In a case where the hoist system 1 is made up of three or more hoists 10, the hoist system 1 outputs its own movement amount L1d to the reference movement amount determination unit 203 of the other hoists 10 as well. Note that communication between three or more hoists 10 is preferably performed by transmitting and receiving the movement amounts L(1 to i)d via the transmitting and receiving unit 120 as shown in FIG. 2.

[0051] The reference movement amount determination unit 203 is a part that determines, by a predetermined calculation, a reference movement amount L1b (target value of the movement amount) of the hoist 10 that has the reference movement amount determination unit 203. This reference movement amount L1b is determined by a predetermined calculation based on its own movement amount L1d (i.e., of the hoist 10 that has the reference movement amount determination unit 203) output from the first let-off point 202 and movement amounts L2d, L3d...Lid output from the first let-off points 202 of the other hoists 10. In addition, the reference movement amount determination unit 203 outputs information on the calculated reference movement amount L1b to the second addition point 204.

[0052] The above-mentioned predetermined calculation may be a calculation of the average value of the movement amounts L1d to Lid of all hoists 10, or may be a determination of the reference movement amount L0d based on the average value of the movement amounts Lid of one predetermined predetermined hoist 10 or a predetermined number of predetermined hoists 10. Alternatively, acceleration information (not shown) of the hoist 10 may be transmitted and received along with the movement amount, and the movement amount Lid of the hoist 10 with the maximum acceleration may be set as the reference movement amount L0d.

[0053] The second summing point 204 also calculates the attitude deviation L1a from the difference between the reference movement amount L0d and the movement amount L1d calculated by the position calculation unit 102.

[0054] The total moment of inertia estimation unit 205 calculates the moment of inertia J1w based on the load w to be hoisted output from the tension calculation unit 103 or the set load W0 to be hoisted, which varies mainly depending on the weight of the workpiece W. At the same time, the moment of inertia J1w is added to the moment of inertia J1 of the hoisting machine 10 itself, such as the drive motor 40, which is stored in advance in memory as a parameter, to calculate all moments of inertia (total moment of inertia J1a) driven by the drive motor 40 of this hoisting machine 10.

[0055] The attitude control torque gain adjuster 206 outputs a coefficient for adjusting the attitude control torque value T1a output by the attitude controller 207 (described later) based on the total moment of inertia J1a.

[0056] The posture controller 207 calculates a posture control torque value T1a using the following formula to correct the torque command so as to reduce the posture deviation L1a, based on the posture deviation L1a output from the second summation point 204 and the coefficient K1j output from the posture control torque gain adjustment unit 206. The coefficient K1a is a coefficient that converts the posture deviation L1a into torque: T1a = K1a × K1j × L1a Note that, in order to improve the accuracy of posture control, it is preferable to add an integral term to the above formula. Furthermore, if the vibration element of the workpiece W is relatively large, PID control may be performed.

[0057] The calculated attitude control torque value T1a is transmitted to the torque command calculation unit 104. The torque command calculation unit 104 outputs to the driver 110 a torque command value Tm obtained by adding the attitude control torque value T1a to a first torque command value shown in (Equation 8)' and (Equation 9)', which is calculated from the set load w0 to be hoisted and the operating force Ws calculated by the tension calculation unit 103, which will be described later. The driver 110 controls the drive motor 40 based on the torque command value Tm. The torque command value obtained by adding the attitude control torque value T1a to the first torque command value corresponds to a second torque command value.

[0058] 4. Control flow of the drive motor 40 of each hoist 10 in the hoist system 1 Next, the control flow of the drive motor 40 of each hoist 10 in the hoist system 1 configured as described above will be described with reference to Fig. 6 to Fig. 10. Note that each of the following steps is executed or determined by the control unit 100 including the attitude control unit 200.

[0059] The control unit 100 determines whether the upper limit switch 80 is activated (step S01). If the upper limit switch 80 is activated, the cylinder operating device 150, the lower hook 160, and the workpiece W are hoisted up to their upper limit positions.

[0060] Therefore, if it is determined in step S01 that the upper limit switch 80 is not activated (No), it is determined that winding is possible, and the drive motor 40 is set to "enabled" in the winding direction (written in the predetermined memory 101) (step S02). On the other hand, if it is determined in step S01 that the upper limit switch 80 is activated (Yes), it is determined that further winding is not possible, and the drive motor 40 is set to "disabled" in the winding direction (written in the predetermined memory 101) (step S03).

[0061] After steps S02 and S03, the control unit 100 determines whether the lower limit switch 81 is activated (step S04). If the lower limit switch 81 is activated, the cylinder operating device 150, the lower hook 160, and the workpiece W are lowered to their lowest positions. If the determination in step S04 determines that the lower limit switch 81 is not activated (No), it is determined that lowering is possible, and the drive motor 40 is set to "enabled" in the lowering direction (written in the predetermined memory 101) (step S05). On the other hand, if the determination in step S04 determines that the lower limit switch 81 is activated (Yes), it is determined that further lowering is not possible, and the drive motor 40 is set to "disabled" in the lowering direction (written in the predetermined memory 101) (step S06).

[0062] After steps S05 and S06, the control unit 100 reads the load measured by the load sensor 90 (step S07). In step S07, the read load value is subjected to appropriate filtering or the like and written to a predetermined memory 101. The filtering may be performed not by the control unit 100 but by an amplifier or the like provided in the load sensor 90, or may be performed by both the control unit 100 and the load sensor 90. The control unit 100 calculates the load torque from the load written to the memory 101 using equations 4 and 5, which will be described later.

[0063] Next, the control unit 100 reads the position information output from the driver 110 (servo driver) (step S08). This position information indicates the payout length of the load chain C1 output by the driver 110 based on information from the encoder 41, which detects the rotation of the drive motor 40 so that the driver 110 (servo driver) can control the drive motor 40 in speed control mode or torque control mode. The output of the encoder 41 may be input directly to the control unit 100 to calculate the payout length of the load chain C1.

[0064] The payout length corresponds to the lift position, and the direction in which the payout length increases is the winding down direction, and the direction in which the payout length decreases is the winding up direction.If the payout length is long, the lift position will be lower, and if the payout length is short, the lift position will be upper.

[0065] Next, the control unit 100 determines whether the load read in step S07 is a preset overload (step S09). If the determination in this step determines that the load read in is not an overload (within the rated load range) (No), the control unit 100 proceeds to step S11, which will be described later. On the other hand, if the determination in step S09 determines that the load read in is an overload (Yes), the control unit 100 determines that the load is an overload and executes overload (abnormality) processing (step S10). Note that the overload (abnormality) processing is processing to prohibit the drive motor 40 from driving, or to perform an emergency stop if the drive motor 40 is operating. At the same time, the control unit 100 also issues a warning or notification of the overload using a buzzer, display, or other means. After the processing in step S10, the control unit 100 proceeds to the determination in step S34, which will be described later.

[0066] If it is determined in step S09 that the load read above is not an overload (within the rated load range) (No), a confirmation process is performed on the operation mode selector switch 151 (step S11). In step S11, the operation mode memory (memory 101) is rewritten to "float mode" or "switch operation mode" using a flip-flop method in response to a signal from the operation mode selector switch 151. After this confirmation process is performed, the control unit 100 reads the operation mode memory (memory 101) and determines whether or not the mode is float mode (step S12). If it is determined that the mode is float mode (Yes), the control unit 100 proceeds to the next step S13. On the other hand, if it is determined in step S12 that the mode is not float mode but switch operation mode (No), the control unit 100 proceeds to step S40, which will be described later.

[0067] If it is determined in step S12 that the mode is float mode (Yes), the setting information (memory 101) from steps S02 and S03 is referenced to determine whether or not driving the drive motor 40 in the winding direction is "enabled" (step S13). If it is determined that driving the drive motor 40 in the winding direction is not possible (No), the float mode, which involves winding and lowering the drive motor 40, cannot be executed, and therefore a stop process is performed to stop the float mode (step S14). The stop process in step S14 includes switching the operation mode memory from "float mode" to "switch operation mode." After this stop process, the program proceeds to step S40, which will be described later (see FIG. 10).

[0068] On the other hand, if it is determined in step S13 that the drive motor 40 can be driven in the winding direction (Yes), the setting information (memory 101) in steps S05 and S06 is referenced to determine whether or not the drive motor 40 can be driven in the winding down direction (step S15). If it is determined in this determination that the drive motor 40 cannot be driven in the winding down direction (No), the float mode involving winding up and down by the drive motor 40 cannot be executed, and therefore a stop process is performed in step S14. This stop process includes switching the operation mode memory from "float mode" to "switch operation mode."

[0069] If it is determined in step S15 that driving in the winding down direction is "enabled" (if Yes), the control unit 100 determines whether or not the mode is "single-action float mode" (step S16). If it is determined to be "single-action float mode" (if Yes), the control unit 100 proceeds to step S19. If it is determined not to be "single-action float mode" (if No), the control unit 100 determines that the float mode to be executed is "attitude control float mode" and proceeds to step S17.

[0070] If it is determined in step S16 that the float mode to be executed is the "posture control float mode," the control unit 100 calculates the posture deviation L1a (Lia for the i-th hoist 10; the same applies below) at the second summation point 204 (step S17).

[0071] That is, when the process proceeds to step S17, the position calculation unit 102 determines whether the posture control start position L1s, which is the basis for the reference posture of the workpiece W in posture control, is stored in the memory 101. If it is not stored, the position information read in step S08 is stored in the memory 101 as the posture control start position L1s. That is, when the process proceeds to the posture control float mode and step S17 is executed for the first time, the position information stored in step S08 is stored in the memory 101 as the posture control start position L1s. Prior to step S08, a step (not shown) may be provided in which the hoists 10A to 10C are operated to hoist or lower the workpiece W so that it assumes the reference posture, thereby setting the posture control start position L1s. Alternatively, the posture control start position L1s may be stored in the memory 101 in advance, and the posture control start position L1s may be selectively called up and set from the memory 101 as needed.

[0072] Then, when the attitude control float mode is started, a movement amount L1d is calculated at a first summing point 201 from the attitude control start position L1s stored in memory 101 and the position information that is the current position L1 read in step 08 (corresponding to a movement amount calculation step). Then, a reference movement amount determination unit 203 calculates and determines a reference movement amount L0d based on its own movement amount L1d input to the reference movement amount determination unit 203 via a first pull-out point 202 and the movement amounts L(2 to i)d input from the other hoists 10 (corresponding to a reference movement amount calculation step). Furthermore, a second summing point 204 calculates an attitude deviation L1a (= L1d - L0d) from the difference between the determined reference movement amount L0d and its own (the first hoist 10's) movement amount L1d (corresponding to an attitude deviation calculation step).

[0073] Following the calculation of the attitude error L1a, the attitude controller 207 calculates an attitude control torque value T1a (step S18; corresponding to the attitude control torque calculation step). Note that, when performing PI control as described above, this attitude control torque value T1a is calculated by adding together a proportional term (P) obtained by multiplying a predetermined function representing the attitude error L1a by a predetermined proportional gain, and an integral term (I) obtained by multiplying a predetermined function representing the attitude error L1a by a predetermined integral gain.

[0074] After step S18, and if the float mode executed in step S16 is determined to be the single-action float mode, the control unit 100 executes a calculation to execute (continue) drive control in the float mode (step S19). When executing this float mode, the control unit 100 calculates the motor torque Tm0 for suspending and holding the workpiece W and the operating force (external force) Ws applied by the operator, as described below, and calculates the motor torque Th of the drive motor 40 corresponding to the operating force Ws. This calculation is performed based on the following formula. Note that the units below can be converted as appropriate.

[0075] First, if the weight of the wound load chain C1 is wcm (kg), the unit weight of the load chain C1 is wc0 (kg), the payout length of the load chain C1 is L (m), and the total length of the load chain C1 is L0 (m), wcm can be calculated as follows: wcm = wc0 × (L0 - L) (Equation 1)

[0076] The weight of the hoisting machine main body 20 is defined as wh (kg). Note that this wh does not include the weight of the load chain C1. The tension calculation unit 103 calculates the load w to be hoisted from the load value Wl (N) measured by the load sensor 90 (load cell). If the acceleration of gravity is g, the load w to be hoisted is calculated as follows using Equation 1: w = Wl / g - (wh + wcm) (Equation 2) The load w to be hoisted corresponds to tension.

[0077] When step S19 is executed for the first time after the float mode is started, the set weight w0 to be hoisted up is calculated as follows from the load value Wl (N) measured by the load sensor 90, which was read in step S07 and stored in memory 101. The load value Wl used to calculate the set weight w0 to be hoisted up is set weight value Wl0. The step of writing the set weight w0 to be hoisted up into memory 101 at the start of float mode is the set weight setting step. However, the set weight w0 to be hoisted up may also be written into memory 101 when a signal from the operation mode changeover switch 151 is confirmed in the above-mentioned step S11, that is, when the float mode is executed in step S19 or before switching, and the set weight setting step may also be called the setting step. w0 = Wl0 / g - (wh + wcm) (Equation 3)

[0078] The set load w0 to be hoisted up written in the memory 101 is the load w to be hoisted up that is first written (set) when the float mode is started, and is not rewritten until the float mode is ended. In other words, the fluctuating set load w to be hoisted up and the set load w0 to be hoisted up that was registered at the start are stored in a predetermined location in the memory 101.

[0079] Also, instead of the set load w0 to be hoisted, the set load value W10 (N) measured at the start may be stored as the load value (set value) in the memory 101. Furthermore, it is advisable to warn the operator with a lamp or the like not to apply an external force to the workpiece W until the set load w0 to be hoisted is registered.

[0080] Here, according to Equation 1, the set load to be hoisted w0 will fluctuate depending on the payout length L of the load chain C1. Therefore, to prevent the set load to be hoisted w0 from fluctuating depending on the payout length L of the load chain C1, it is possible to store the set load to be hoisted in memory 101 by dividing it into two parts: (A) "the part of the load chain C1 corresponding to the payout length L," which is the part where the load fluctuates, and (B) the remaining part. Note that if the change in weight of (A) "the part of the load chain C1 corresponding to the payout length L" is small enough to be ignored compared to the operating force Ws or the load to be hoisted w0, i.e., in the case of a hoist with a short lifting range, it is possible to ignore the weight of (A).

[0081] Here, the force with which the worker lifts or pushes down the workpiece W, the cylinder operating device 150, or the lower hook 160 is defined as the operating force Ws (N). This operating force Ws is calculated as follows: Ws = (w0 - w) x g (Equation 4) or Ws = Wl0 - Wl (Equation 4')

[0082] In (Equation 4), when the operator tries to lift the workpiece W or the like, the load (load to be hoisted) w measured by the load sensor 90 becomes smaller (lighter) than the set load (set load to be hoisted) w0, so the operating force Ws becomes positive. On the other hand, when the operator tries to push down the workpiece W or the like, the load w measured by the load sensor 90 becomes larger (heavier) than the set load w0, so the operating force Ws becomes negative. The operating force Ws (= w0 - w) is the operating load applied by the operator to the workpiece W in the lifting direction, detected by the load sensor 90 and calculated by the tension calculation unit.

[0083] In the float mode, the motor torque Tm0 (Nm) of the drive motor 40 for holding the set load w0 (kg) to be hoisted is calculated by the following formula, where i is the reduction ratio of the reduction mechanism 50 and r (m) is the radius of action of the load sheave 70. The motor torque Tm0 corresponds to the holding torque. Tm0 = (1 / i) x r x g x w0 (Formula 5)

[0084] The motor torque Th (Nm) of the drive motor 40 corresponding to the operating force Ws can be calculated using the following formula: Th=(1 / i)×r×Ws (Formula 6)

[0085] In this way, in step S19, the motor torque Tm0 for holding the set load w0 to be hoisted that was set and registered at the time the single-action float mode or attitude control float mode was started, and the motor torque Th corresponding to the operating force Ws are calculated. Then, it is determined whether the length L of the load chain C1 paid out from the load sheave 70 is equal to or less than the upper stop length (payout length) UL (equal to or greater than the upper stop position in terms of the lifting position) (step S20).

[0086] 11, the length L of the load chain C1 unwound from the load sheave 70 is the length (distance) from the upper limit position MT1 at which the upper limit switch 80 operates to the upper end of the cylinder operating device 150. The upper stop length UL is the length (distance) between the upper limit position MT1 at which the upper limit switch 80 operates and the upper stop position MT2, which is the upper limit position in float mode.

[0087] The upper stop position MT2 is a software upper limit position for the lifting of the cylinder operating device 150 (the lower hook 160 and the workpiece W). The upper stop position MT2 may be determined by user settings or calculated using a predetermined calculation formula. When the upper stop position MT2 is determined each time by user settings, it can be set using the switch operation mode described below.

[0088] In the judgment of step S20 above, if it is determined that the payout length L of the load chain C1 is less than the upper stop length UL (if Yes), then it is determined whether the operator's operating force Ws calculated by (Equation 4) is greater than 0 (positive) (step S21).

[0089] That is, as described in the above (Equation 4), when the operating force Ws is positive, the operator is applying force to the workpiece W in the direction of lifting the workpiece W (hoisting direction). Therefore, when it is determined in step S21 that the operator's operating force Ws is greater than 0 (positive), the control unit 100 creates a torque command value Tm shown in the following (Equation 7) (step S22). Tm = Tm0 - Kl × Th (Equation 7) Note that posture control is not performed in step S22.

[0090] In this way, the lifting position range of the workpiece W is set to a position range above the upper stop position MT2, and within this set position range, it is determined whether or not to perform restriction control depending on the direction of the operating force Ws.If restriction is necessary, the torque command value Tm calculated by (Equation 7) is output from the control unit 100 to the driver 110 (servo driver) to control the torque of the drive motor 40.

[0091] The control unit 100 then outputs the created torque command value Tm to the driver 110, and the driver 110 drives the drive motor 40 with power based on this torque command value Tm. The value of "-Kl x Th" in the torque command value Tm calculated by (Equation 7) corresponds to the cancel torque. As described above in (Equation 4), the value of "-Kl x Th" becomes a negative value when the operator applies a force in a direction lifting the workpiece W, and becomes a positive value when the operator applies a force in a direction pushing down the workpiece W. By adding the cancel torque "-Kl x Th" to the motor torque Tm0 for maintaining the set load w0 to be hoisted, the lifting of the workpiece W can be reliably restricted, even if the operator attempts to lift the workpiece.

[0092] In the above formula, Kl is a gain that represents the amplification factor, but if the value of gain Kl is less than the mechanical efficiency (η), the motor torque value corresponding to the torque command value "-Kl x Th" of the torque command value Tm generated by the drive motor 40 in response to the operating force Ws of the operator will become small and will be overwhelmed by the operating force Ws, which may result in insufficient position regulation. Therefore, it is preferable and reliable to set the value of gain Kl to be equal to or greater than the mechanical efficiency (η), for example, "1."

[0093] Depending on the specifications of the hoist 10, the value of "-Kl x Th" may be set to a fixed value that allows the operator to recognize that the upper stop position MT2 or the lower stop position MB2 has been reached, i.e., that the operation feels heavy or even heavier.

[0094] After step S22, the control unit 100 makes a determination in step S34, which will be described later.

[0095] Also, if it is determined in step S19 that the payout length L of the load chain C1 is greater than the upper stop length UL (below the upper stop position MT2 based on the lifting position) (No), then it is determined whether the payout length L of the load chain C1 is greater than the lower stop length LL (below the lower stop position MB2 based on the lifting position) (step S23).

[0096] 11, the lower stop length LL is the length (distance) between the upper limit position MT1 at which the upper limit switch 80 operates and the lower stop position MB2, which is the lower limit position in float mode. The range between the upper stop position MT2 and the lower stop position MB2 corresponds to the first position range and the balancer intermediate position range. The range between the upper limit position MT1 and the upper stop position MT2 and the range between the lower limit position MB1 and the lower stop position MB2 correspond to the second position range.

[0097] Like the upper stop position MT2, the lower stop position MB2 is a software lower limit position for lowering (paying out) the cylinder operating device 150 (the lower hook 160 and the workpiece W). The lower stop position MB2 is located above the lower limit position MB1 at which the lower limit switch 81 activates. The lower stop position MB2 may be determined by user settings or calculated using a predetermined formula. Preferably, the signal from either the upper limit switch 80 or the lower limit switch 81 serves as a reset signal for the reference position of the payout length (lifting position) of the load chain C1. However, depending on the specifications of the hoist 10, neither the upper limit switch 80 nor the lower limit switch 81 is an essential component, and only the upper stop position MT2 or the lower stop position MB2 may be set.

[0098] In the judgment of step S23 above, if it is determined that the payout length L of the load chain C1 is equal to or greater than the lower stop length LL (or equal to or less than the lower stop position MB2 based on the lifting position standard) (if Yes), it is then determined whether the operator's operating force Ws is less than 0 (negative) (step S24).

[0099] That is, as described in the above (Equation 4), when the operating force Ws is negative, it means that the operator is applying force to the workpiece W in a direction that pushes down the workpiece W. Therefore, when it is determined in step S24 that the operator's operating force Ws is less than 0 (negative), the control unit 100 proceeds to the above-mentioned step S22. That is, the torque command value Tm shown in (Equation 7) is created.

[0100] Then, the control unit 100 outputs the generated torque command value Tm to the driver 110, and the driver 110 drives the drive motor 40 with power based on the torque command value Tm.

[0101] When the workpiece W is pushed down, the sign of Th is opposite to that when the workpiece W is lifted. Therefore, in (Equation 7), when "-Kl x Th" corresponding to the operating force Ws of the operator is added to the motor torque Tm0 of the drive motor 40, the drive motor 40 is driven at a torque command value Tm in a state in which the operating force Ws pushing down the workpiece W is canceled. Therefore, the workpiece W will not move in the pushing down direction, even though the operator is trying to push it down (try to wind up the workpiece W).

[0102] In this way, the lifting position range of the workpiece W is set as a position range above the upper stop position MT2 and / or below the lower stop position MB2, and it is determined in steps S20 and S23 whether the workpiece W is within this set position range. Then, in steps S21 and S24, it is determined whether or not to perform restriction control depending on the direction of the operating force Ws within this set position range. If restriction is necessary, the torque command value Tm calculated in step S22 using (Equation 7) is output from the control unit 100 to the driver 110 (servo driver) to control the torque of the drive motor 40.

[0103] In steps S21 and S24, as well as steps S27 and S30 (described later), the determination is made based on the value of the operating force Ws. However, in the posture control float mode, the determination can be made based on a torque value obtained by adding the attitude control torque value T1a to the motor torque value T1a of the drive motor 40, which corresponds to the operating force Ws, instead of the operating force Ws. That is, in steps S21 and S27, the determination is made based on "(Th + T1a) > 0?", and in steps S24 and S30, the determination is made based on "(Th + T1a) < 0?" before proceeding to the next step. In this way, even if the payout length L1 of the load chain C1 is shorter than the upper stop length UL and the upper decay length UD, or longer than the lower stop length LL and the lower decay length LD, if the torque plus the attitude control torque value T1a is acting in a direction that allows lifting and lowering, the torque can be controlled so as not to interfere with its action.

[0104] Furthermore, depending on the specifications of the hoist 10, the value of "-Kl x Th" may be set to a fixed value to an extent that allows the operator to recognize that the upper stop position MT2 or the lower stop position MB2 has been reached, i.e., to an extent that the operation feels heavy.

[0105] Furthermore, if the judgment in step S23 above determines that the payout length L of the load chain C1 is smaller than the lower stop length LL (above the lower stop position MB2 based on the lifting position standard) (No), the control unit 100 determines whether the length L of the load chain C1 is equal to or smaller than the upper damping length UD (step S25).

[0106] Here, the upward damping length UD is the length (distance) between the upper limit position MT1 at which the upper limit switch 80 operates and the upward damping start position MT3 at which the assist force in the direction to lift the workpiece W (hoisting direction) is gradually weakened. In the following description, the region between the upper stop position MT2 and the upward damping start position MT3 is referred to as the upward damping region UAR. In this embodiment, this upward damping region UAR coincides with a speed deceleration region (upper speed deceleration region USR; described below) that forcibly decelerates the speed at which the workpiece W advances in the direction to be lifted (hoisting direction). However, the upper speed deceleration region USR and the upward damping length UD may not coincide with each other and may be set to be separate regions.

[0107] If it is determined in step S25 above that the length L of the load chain C1 is equal to or less than the upper damping length UD (if Yes), the workpiece W is approaching the upper stop position MT2, and if posture control of the workpiece W is performed while the workpiece W is approaching the upper stop position MT2, there is a risk that the workpiece W will pass over the upper stop position MT2. Therefore, if the posture control torque value T1a is in the hoisting direction, the control unit 100 decreases the posture control torque value T1a at a predetermined slope so that the posture control torque value T1a = 0 as the workpiece W approaches the upper stop position MT2 (step S26).

[0108] After step S26, the control unit 100 determines whether the operating force Ws of the operator calculated by (Equation 4) is greater than 0 (positive) or not (step S27), similarly to step S21.

[0109] If it is determined in step S27 that the operating force Ws is equal to or less than 0 (No), the process proceeds to step S28, which will be described next. On the other hand, if it is determined in step S27 that the operating force Ws is greater than 0 (Yes), the process proceeds to step S32, which will be described later.

[0110] Furthermore, if the judgment in step S25 above determines that the length L of the load chain C1 is greater than the upward damping length UD (if No), and if the judgment in step S27 determines that the operating force Ws is 0 or less (if No), the control unit 100 then determines whether the length L of the load chain C1 is greater than or equal to the downward damping length LD (step S28).

[0111] Here, the downward damping length LD is the length (distance) between the upper limit position MT1 at which the upper limit switch 80 operates and the downward damping start position MB3 at which the assist force in the direction of pushing down the workpiece W (the winding-down direction) is gradually weakened. In the following description, the region between the lower stop position MB2 and the downward damping start position MB3 is referred to as the downward damping region LAR. In this embodiment, this downward damping region LAR coincides with a speed deceleration region (lower speed deceleration region LSR; described below) that forcibly decelerates the speed at which the workpiece W advances in the direction of pushing down (the winding-down direction). However, the downward speed deceleration region LSR and the downward damping region LAR may not coincide with each other and may be set to be separate regions.

[0112] Furthermore, in the judgment of step S28 above, if it is judged that the length L of the load chain C1 is equal to or greater than the downward damping length LD (if Yes), the workpiece W is approaching the downward stop position MB2, and if the posture of the workpiece W is controlled while approaching the downward stop position MB2, there is a risk that the workpiece W will pass over the downward stop position MB2. Therefore, when the posture control torque value T1a is in the lowering direction, the control unit 100 decreases the posture control torque value T1a at a predetermined slope so that the posture control torque value T1a = 0 as the workpiece approaches the downward stop position MB2 (step S29).

[0113] After step S29, the control unit 100 determines whether the operating force Ws of the operator calculated by (Equation 4) is less than 0 (is negative) in the same manner as in step S24 (step S30).

[0114] If it is determined in step S30 that the operating force Ws is equal to or greater than 0 (No), the process proceeds to step S31, which will be described next. On the other hand, if it is determined in step S30 that the operating force Ws is less than 0 (Yes), the process proceeds to step S32, which will be described later.

[0115] Furthermore, if it is determined in step S28 that the length L of the load chain C1 is smaller than the downward damping length LD (if No), and if it is determined in step S29 that the operating force Ws is equal to or greater than 0 (if No), the control unit 100 creates a torque command value Tm as shown in the following (Equation 8) and transmits it to the driver 110 (step S31): Tm=Tm0+Kh×Th+T1a... (Equation 8)

[0116] In the above (Equation 8), "Kh x Th" corresponds to the assist torque. Furthermore, since the above attitude control torque value T1a is the attitude control torque of the first hoisting machine 10, when this is the i-th hoisting machine 10, T1a in the above (Equation 8) is replaced with Tia. Furthermore, driving of the drive motor 40 with the torque command value Tm shown in the above (Equation 8) also corresponds to a drive control step, similar to driving of the drive motor 40 in (Equation 7).

[0117] Furthermore, the torque command value Tm calculated by the above (Equation 8) corresponds to the second torque command value and is used to control the posture of the workpiece W. However, when controlling the elevation of the workpiece W in a single-action float mode without posture control, instead of the above (Equation 8), the torque command value Tm (corresponding to the first torque command value) calculated by the following (Equation 8)' can be calculated and the drive motor 40 can be controlled by using the torque command value Tm = Tm0 + Kh × Th ... (Equation 8)'

[0118] Incidentally, even in the single-acting float mode, the torque command value may be calculated using the above (Equation 8). In this case, when control is performed in the single-acting float mode, steps S17 and S18 for executing the attitude control float mode are not executed. In this case, the attitude control torque value T1a is not calculated, and the value of the attitude control torque value T1a is set to zero in (Equation 8), and the torque command value Tm is calculated.

[0119] In the above equation, Kh is a gain representing the amplification factor, which is determined experimentally, taking into account the mechanical efficiency, acceleration, etc., of the drive motor 40. To ensure good operability in float mode, this gain Kh is set to a value sufficiently larger than 1, for example, so that the ratio of the value of Kh × Th to Tm0 is approximately 5 to 20%. Note that the Kh during hoisting and the Kh during lowering may be different values, for example, the hoisting Khu may be smaller than the lowering Khd. [Tm0] is the motor torque required to maintain the set load w0 to be hoisted. By applying a hoisting assist torque [Khu × Th] or a lowering assist torque [Khu × Th], the drive motor 40 rotates in the hoisting or lowering direction to assist the operator's operating force Ws, and the workpiece W is raised or lowered.

[0120] As is clear from Equation 8, the control unit 100 calculates the torque command value Tm by adding the assist torque "Kh x Th," which is obtained by multiplying the motor torque Th corresponding to the operating force Ws by a predetermined gain Kh, to the motor torque Tm0 of the drive motor 40 for holding the set load w0 to be hoisted, and then adding the attitude control torque value T1a. Therefore, the workpiece W can be moved up and down by lightly pushing it up or down without using the operation switch 180. Furthermore, even if one end of the workpiece W is grasped and raised or lowered, the workpiece W can be raised or lowered while performing attitude control such that the workpiece W returns to its initial attitude (e.g., a horizontal attitude) when the attitude control float mode was initiated.

[0121] In this way, the torque command value Tm is output from the control unit 100 to the driver 110 in the first float mode, calculated using (Equation 8) or (Equation 10) described later, when assisting, and in the second float mode, calculated using (Equation 7) when restricting lifting and lowering. Furthermore, since the lifting position ranges controlled in the first float mode and the second float mode can be set and registered, it becomes possible to restrict the direction of lifting and lowering at the upper stop position MT2 and / or the lower stop position MB2 without interrupting the torque control of the drive motor 40.

[0122] Furthermore, when the operator is pushing the workpiece W upward (hoisting command operation), if the payout length L of the load chain C1 exceeds the upper stop length UL but is equal to or less than the upper damping length UD (if the upper end of the cylinder operating device 150 is located within the upper speed deceleration region USR), the upper end of the cylinder operating device 150 will immediately reach the upper stop position MT2, which is the software upper limit position. If the operator is pushing the workpiece W upward in such an upper speed deceleration region USR, the workpiece W will be suddenly decelerated or stopped when the upper end of the cylinder operating device 150 reaches the upper stop position MT2.

[0123] Similarly, when the operator is pushing the workpiece W downward (lowering command operation), if the payout length L of the load chain C1 is shorter than the downward stop length LL but equal to or greater than the downward decay length LD (when the upper end of the cylinder operating device 150 is located within the downward speed deceleration region LSR), the upper end of the cylinder operating device 150 will immediately reach the lower stop position MB2, which is the software's lower limit position. If the operator is pushing the workpiece W downward in such a downward speed deceleration region LSR, the workpiece W will be suddenly decelerated or stopped when the upper end of the cylinder operating device 150 reaches the lower stop position MB2.

[0124] Therefore, when the upper end of the cylinder operating device 150 enters the upper speed deceleration region USR, which is located in front of the upper stop position MT2 (lower position), and the lower speed deceleration region LSR, which is located in front of the lower stop position MB2 (upper position), it is preferable that the control unit 100 controls the drive motor 40 so as to forcibly decelerate the workpiece W.

[0125] Therefore, the control unit 100 performs a deceleration process of the drive motor 40 (step S32) when the determination in step S27 determines that the operating force Ws is greater than 0 and the operator is pushing up the workpiece W (a hoisting command operation) (if Yes). The control unit 100 also performs a deceleration process of the drive motor 40 in step S32 when the determination in step S30 determines that the operating force Ws is less than 0 and the operator is pushing down the workpiece W (a lowering command operation) (if Yes). The speed deceleration in the upper speed deceleration region USR and the lower speed deceleration region LSR is illustrated in FIG. 12 . While FIG. 12 illustrates a state in which the speed is proportionally decelerated, the drive motor 40 may be controlled so that the speed is decelerated in a state other than a proportional speed deceleration.

[0126] Furthermore, in this embodiment, as described above, the upper speed deceleration region USR is made to coincide with the upper attenuation region UAR, so when the upper end of the cylinder operating device 150 is in the upper speed deceleration region USR, the upper end of the cylinder operating device 150 will also be in the upper attenuation region UAR. Furthermore, in this embodiment, as described above, the lower speed deceleration region LSR is made to coincide with the lower attenuation region LAR, so when the upper end of the cylinder operating device 150 is in the lower speed deceleration region LSR, the upper end of the cylinder operating device 150 will also be in the lower attenuation region LAR.

[0127] Therefore, in addition to the deceleration process of the drive motor 40 in step S32, the control unit 100 generates a torque command value Tm as shown in the following (Equation 9) (step S33). Tm=Tm0+Kh'×Th+T1a (Equation 9) Note that the process of step S33 may be performed before the process of step S32. Furthermore, driving the drive motor 40 with the torque command value Tm shown in (Equation 9) above also corresponds to a drive control step, similar to driving the drive motor 40 with (Equation 7).

[0128] Furthermore, the torque command value Tm calculated by the above (Equation 9) corresponds to the second torque command value and is used to control the posture of the workpiece W. However, when controlling the elevation of the workpiece W in a single-action float mode without posture control, instead of the above (Equation 9), the torque command value Tm (corresponding to the first torque command value) calculated by the following (Equation 9)' can be calculated and the drive motor 40 can be driven and controlled. Tm = Tm0 + Kh' x Th ... (Equation 9)'

[0129] Here, Kh' in the above (Equation 9) is a coefficient for providing a torque command value Tm that changes in the upper damping region UAR or the lower damping region LAR, as shown in Figures 13A and 13B. Therefore, as is clear from a comparison with the above (Equation 8), the coefficient Kh' is a variable that varies depending on the position within the upper damping region UAR or the lower damping region LAR, unlike the coefficient Kh, which is a fixed value. Note that in Figures 13A and 13B, Kh' is a variable that changes the torque command value Tm as a linear function within the upper damping region UAR or the lower damping region LAR. However, Kh' may be a variable that causes a change other than a linear function, such as an exponential function.

[0130] When the torque command value Tm as shown in Equation 9 is transmitted to the driver 110 to control and drive the drive motor 40, the assisting force provided by the drive motor 40 to assist the operating force Ws gradually weakens as the upper end of the cylinder operating device 150 approaches the upper stop position MT2 or the lower stop position MB2. Moreover, the assisting force decreases whether the moving speed of the workpiece W is high or low.

[0131] Therefore, the operator feels that the response when applying the operating force Ws to the workpiece W becomes heavier as the workpiece W approaches the upper stop position MT2 or the lower stop position MB2. This allows the operator to intuitively understand that the upper end of the cylinder operating device 150 (workpiece W) is approaching the upper stop position MT2 or the lower stop position MB2, not only when the workpiece W is moving at high speed but also when the workpiece W is moving at low speed.

[0132] However, in (Equation 9), the posture control torque value T1a is added, so that the posture of the workpiece W can be controlled.

[0133] After executing the processes of steps S10, S14, S22, S31, and the aforementioned step S33, the control unit 100 determines whether or not to stop the drive control of the drive motor 40, which consists of the single-action float mode, attitude control float mode, and switch operation mode, in response to an abnormality signal or input of a command (not shown) (step S34). If it is determined that the drive control should be stopped (Yes), the control unit 100 transitions to processing, such as a maintenance mode (not shown), based on each command, and terminates the drive control program. On the other hand, if it is determined in step S34 that the drive control should not be stopped (to be continued) (No), the control unit 100 returns to the determination of step S01 described above and continues the drive control.

[0134] Next, the switch operation mode will be described. If it is determined in step S12 above that the float mode (single-acting or attitude control float mode) is not selected (No), the switch operation mode is executed (continued) (step S40). That is, the execution program for the switch operation mode is read from memory 101, and a command for the speed control mode is output to driver 110 (servo driver).

[0135] Next, the control unit 100 checks the displacement sensor 153 provided in the cylinder operating device 150 (step S41). That is, the position of the movable grip 152 is confirmed by the displacement sensor 153. Then, the winding-up and winding-down are set based on the sliding position of the movable grip 152.

[0136] Next, the control unit 100 refers to the setting information (memory 101) from steps S02 and S03 to determine whether or not the drive motor 40 can be driven in the film winding direction (step S42). That is, the same determination as in step S13 is made. If it is determined in step S42 that the drive motor 40 cannot be driven in the film winding direction (No), the control unit 100 determines whether or not a command to perform film winding has been issued (step S43). That is, this determination is made based on the confirmation result (memory 101) of whether or not the movable grip 152 has been slid in the film winding direction in step S41.

[0137] Here, it has already been determined in step S42 that the drive motor 40 on the winding side cannot be driven, i.e., "impossible." Therefore, if it is determined in step S43 above that a command to wind up has been issued (if Yes), processing is then performed to stop the drive motor 40 in the winding direction and to activate the brake mechanism 60 (step S44).

[0138] On the other hand, if it is determined in step S42 that the drive motor 40 can be driven in the film winding direction (Yes), or if it is determined in step S34 that a command to wind the film has not been issued (No), the control unit 100 then refers to the setting information (memory 101) in steps S05 and S06 to determine whether or not the drive motor 40 can be driven in the film winding direction (step S45). That is, the control unit 100 makes the same determination as in step S15. If it is determined in step S45 that the drive motor 40 cannot be driven in the film winding direction (No), the control unit 100 determines whether or not a command to wind the film has been issued (step S46). That is, the control unit 100 makes this determination based on the result of the determination (memory 101) in step S41 as to whether or not the movable grip 152 has been slid in the film winding direction.

[0139] Here, it has already been determined in step S45 that the drive motor 40 on the winding side cannot be driven, i.e., "impossible." Therefore, if it is determined in step S46 above that a command to wind up has been issued (Yes), processing is then performed to stop the drive motor 40 in the winding direction and to activate the brake mechanism 60 (step S47).

[0140] On the other hand, if it is determined in step S45 that the drive motor 40 can be driven in the winding direction (Yes), the control unit 100 creates a speed command and outputs it to the driver 110 (step S48). This speed command is created based on the value of the memory 101 that stores the detection signal from the displacement sensor 153 that detects the sliding position of the movable grip 152 in step S41.

[0141] Next, regarding the driving range of the drive motor 40, it is determined whether or not there is a need (request) to set the upper stop length (extension length) UL and the lower stop length (extension length) LL as shown in Figure 11 (step S49). That is, depending on the operating environment of the cylinder operating device 150, it may be preferable to change the settings of the upper limit position and the lower limit position in software. Therefore, in step S49, whether or not there is a request to set (reset) the upper stop length UL and the lower stop length (extension length) LL is determined, for example, based on the length of the ON signal from the change-over switch.

[0142] If it is determined in step S49 that the upper stop length UL and the lower stop length LL need to be set (Yes), the upper stop length UL and the lower stop length LL are set (step S50). In other words, the operating range of the cylinder operating device 150 is determined by software. After the processing of step S50, the control unit 100 determines whether to stop (continue) the drive control of the drive motor 40, as described in step S33 above.

[0143] Also, if the judgment in step S49 determines that there is no need to set the upper stop length UL and the lower stop length LL (if No), the control unit 100 determines whether to stop (continue) the drive control of the drive motor 40, as explained in step S33 above.

[0144] The above-described control flow is executed when the drive motor 40 of the hoisting machine 10 is driven.

[0145] [5. Supplementary Note] The contents of the present embodiment described above can be understood, for example, as follows, and can further produce the following effects: [1] That is, in the hoist system 1 of this embodiment, which is provided with a plurality of hoists 10 and which raises and lowers one workpiece W by winding up and down the load chain C1 or rope of each hoist 10, each hoist 10 is arranged in a hoist main body 20, has a load sheave 70 (hoisting means) around which the load chain C1 or rope is wound and which winds up and down the load chain C1 or rope in response to rotation, a drive motor 40 which generates a driving force to rotate the load sheave 70 (hoisting means), a control unit 100 and a driver 110 (motor control means) which control the drive of the drive motor 40, the load sensor 90 and tension calculation unit 103 (load detection means) for detecting the set load w0 to be hoisted (tension of the load chain C1 or rope) applied to the load sheave 70 (hoisting means) and the operating force Ws (= w0 - w) applied to the load chain C1 or rope when the operator operates the workpiece W in the hoisting / lowering direction, and an encoder 41 (position detection means) for detecting the payout length L of the load chain C1 (position of the load chain or rope), wherein the control unit 100 and driver 110 (motor control means) are capable of controlled driving in a float mode (torque control mode) in which the drive motor 40 is driven based on a first torque command value [Tm0 + Kh × Th] obtained by adding an assist torque [Kh × Th] that assists the operating force Ws to a motor torque Tm0 (holding torque) that can hold the set load w0 to be hoisted (tension of the load chain C1 or rope),The control unit 100 and the driver 110 (motor control means) calculate their own movement amount L1 from the payout length L (position) of the load chain C1 detected by the encoder 41 (position detection means), and transmit their own calculated movement amount L1d to the other hoists 10. The posture controller 207 determines a reference movement amount L0d based on their own movement amount L1d and the received movement amounts L(2 to i)d of the other hoists 10, and calculates a posture control torque value T1a for controlling the posture of the workpiece W based on the difference between the reference movement amount L0d and their own movement amount L1d. The control unit 100 and the driver 110 (motor control means) are capable of posture control for controlling the posture of the workpiece W in float mode (torque control mode), and in this posture control, the drive of the drive motor 40 is controlled based on a second torque command value [Tm0 + Kh × Th + T1a] obtained by adding the posture control torque value T1a to the first torque command value.

[0146] When controlling in this manner, even if a plurality of hoists 10 cooperate to perform hoisting control in float mode, which is torque control, a reference movement amount is determined based on the movement amount of each hoist 10 (amount of ascent and descent from a reference position), and the posture control unit 200 calculates a posture control torque for returning the workpiece W to the reference posture based on the deviation between the reference movement amount and the movement amount of the hoist 10 itself. Therefore, even if there is a delay in obtaining information on the movement amounts of the other hoists 10, hoisting control by torque control of each hoist is performed smoothly, and even if a difference occurs between the movement amount and the reference movement amount as a result of each hoisting control, the posture control torque works to correct the posture of the workpiece W. Therefore, high-speed communication and high-speed processing are not required between the hoists 10, and posture control for returning the workpiece W to the basic posture can also be performed while raising and lowering the workpiece W in torque control mode.

[0147] Furthermore, in each hoisting machine 10, a posture control torque for controlling the posture of the workpiece W is calculated based on the difference between the reference movement amount and the current position of the connection portion of the workpiece W, and in the posture control of the workpiece W, the driving of the drive motor 40 is controlled based on a second torque command value obtained by adding the posture control torque to the first torque command value, so it is possible to return the workpiece W to a reference posture. Therefore, it is possible to put the workpiece W into a posture that is preferable for the worker.

[0148] As described above, the attitude of the workpiece W is controlled by controlling the drive of the drive motor 40 based on the second torque command value obtained by adding the attitude control torque to the first torque command value. Therefore, the operator can finely adjust the attitude of the workpiece W by applying an operating force Ws that overcomes the attitude control torque value T1a. For example, when inserting the hole portion of the workpiece W into an external shaft portion, the workpiece W is first tilted, and the shaft portion is first inserted into some of the holes for positioning, and then the attitude of the workpiece W is controlled to an attitude in which the workpiece W is moved by a reference movement amount. Therefore, after the shaft portion other than some of the holes is inserted, the workpiece W is controlled to an attitude that makes it easy to insert the shaft portion into other holes, thereby improving workability.

[0149] [2] Furthermore, in the above-described embodiment, in the content of [1] above, the posture control unit 200 may calculate the posture control torque based on the posture deviation (the difference between the reference movement amount and its own movement amount) and all moments of inertia including the set load w0 to be hoisted that each hoisting machine 10 is responsible for.

[0150] In this way, by reflecting all the inertia moments handled by each hoisting machine 10 in the posture control torque, it is possible to control the posture with a similar sense of speed regardless of the size of the load when lifting or lowering the workpiece W.

[0151] [3] Furthermore, in the above-described embodiment, in addition to the contents described in either [1] or [2] above, or a combination thereof, the reference movement amount may be the average value of the movement amounts (L1d, L2d, L3d) of a predetermined hoist (10A, 10B, 10C) selected from a plurality of hoists (10A, 10B, 10C).

[0152] In this way, by using a predetermined average value of the movement amount of the hoist 10 to calculate the attitude deviation, the calculation of the attitude deviation becomes easy.

[0153] In addition, when calculating the above average value, the movement amounts (L1d, L2d, L3d, ...) of all the hoists (10A, 10B, 10C, ...) that make up the hoist system 1, which is a predetermined hoist 10, may be totaled and the average value may be calculated.

[0154] Furthermore, it may be an average value of the movement amounts (L1d, L2d) of some predetermined hoists 10, or it may include using the movement amount L1d, which is the average value of the movement amounts L1d of one of the specific hoists 10A, as the reference movement amount. As a result, when a plurality of workers operate the lifting and lowering of the workpiece W according to the state of the hoisting work, the lifting and lowering of the workpiece W by each hoist 10 can be corrected based on the movement amounts of all or more than half of the hoists 10, and when it is desired to imitate the lifting and lowering of other parts of the workpiece W, one or two hoists 10 close to that part can be registered in advance, and the average value of the movement amounts of the registered hoists 10 can be used as the reference movement amount to correct the lifting and lowering of the workpiece W by each hoist.

[0155] [4] Furthermore, in this embodiment, in addition to the contents described in any one of [1] to [3] above or a combination thereof, the posture control unit 200 may calculate a posture control torque for controlling the posture of the workpiece W based on PI control.

[0156] In this way, by calculating the attitude control torque for controlling the attitude of the workpiece W based on PI control, the attitude of the workpiece W can be brought closer to a target value by proportional control (P control), and the deviation (error) from the target value can be eliminated by integral control (I control). Therefore, for example, in an operation such as inserting a shaft into a hole in the workpiece W, after slightly tilting the workpiece W to insert the shaft into a part of the hole, it is possible to precisely control the attitude of the workpiece W to a target attitude, such as a horizontal attitude.

[0157] Furthermore, the contents described in the above-described embodiment can be understood as follows, for example, and can further produce the following effects: [5] That is, in a control method for a hoist system 1 that includes a plurality of hoists 10 and that raises and lowers one workpiece W by winding up and down the load chain C1 or rope of each hoist 10, each hoist 10 is disposed in a hoist main body 20, has a load chain C1 (load chain or rope) wound therearound, and has a load sheave 70 (hoisting means) that winds up and lowers the load chain C1 in response to rotation, a drive motor 40 that generates a driving force to rotate the load sheave 70 (hoisting means), a control unit 100 and a driver 110 (motor control means) that control the drive of the drive motor 40, the load sensor 90 and tension calculation unit 103 (load detection means) for detecting the set load w0 to be hoisted (tension of the load chain C1 or rope) applied to the load sheave 70 (hoisting means) and the operating force Ws (= w0 - w) applied to the load chain C1 or rope when the operator operates the workpiece W in the hoisting / lowering direction, and an encoder 41 (position detection means) for detecting the payout length L of the load chain C1 (position of the load chain C1 or rope), wherein the control unit 100 and driver 110 (motor control means) are capable of controlled driving in a float mode (torque control mode) in which the drive motor 40 is driven based on a first torque command value [Tm0 + Kh × Th] obtained by adding an assist torque [Kh × Th] that assists the operating force Ws to a motor torque Tm0 (holding torque) that can hold the set load w0 to be hoisted (tension of the load chain C1 or rope), In the float mode (torque control mode), it is possible to perform posture control to control the posture of the workpiece W. In this posture control, the payout length (L1, L2, ...;a movement amount calculation step of calculating respective movement amounts (L1d, L2d, ...) from the respective positions of the workpieces W; a reference movement amount determination step of transmitting the movement amount L1 to the other hoisting machines 10 and determining a reference movement amount L0d; a posture deviation calculation step of calculating a difference L1a between the reference movement amount L0d and the workpiece W's own movement amount L1d; a posture control torque calculation step of calculating a posture control torque value T1a for controlling the posture of the workpiece W based on the difference L1a; and a drive control step of controlling the drive of the drive motor 40 based on a second torque command value [Tm0+Kh×Th+T1a] obtained by adding the posture control torque value T1a to the first torque command value [Tm0+Kh×Th].

[0158] In this control method for the hoist 10, a reference movement amount L0d is determined in a reference movement amount determination step that calculates and determines a reference movement amount using a predetermined reference movement amount determination method, and an attitude control torque value T1a for controlling the attitude of the workpiece W in the attitude controller 207 is calculated based on the difference L1a between the reference movement amount and the current position. Therefore, based on the movement amount of each hoist 10 that is lifting or lowering the workpiece W, when a difference occurs between the posture of the workpiece W and the reference posture while each hoisting control is being performed by torque control, an attitude control torque in a direction that reduces the difference is calculated and added to the first torque command. Therefore, there is no need to aggregate measured forces or calculate force target values ​​based on the forces in accordance with the calculation cycle in force control. In other words, there is no need to aggregate forces that require high-speed communication and high-speed processing.

[0159] Furthermore, in each hoisting machine 10, an attitude control torque for controlling the attitude of the workpiece W is calculated based on the attitude deviation between the reference movement amount and the current position of the connection portion of the workpiece W, and in the drive control step, the drive of the drive motor 40 is controlled based on a second torque command value obtained by adding the attitude control torque to the first torque command value, so it is possible to return the workpiece W to a reference attitude. Therefore, it is possible to put the workpiece W into a posture that is preferable for the worker.

[0160] Furthermore, as described above, in the drive control step, the drive of the drive motor 40 is controlled based on the second torque command value obtained by adding the posture control torque to the first torque command value, thereby controlling the posture of the workpiece W. Therefore, for example, when inserting the hole portion of the workpiece W into an external shaft portion, the workpiece W is first tilted, and the shaft portion is first inserted into some of the holes for positioning, and then the posture of the workpiece W is controlled to a posture in which the workpiece W is moved by a reference movement amount. Therefore, after the shaft portion other than some of the holes is inserted, the posture of the workpiece W is controlled to a posture that makes it easy to insert the shaft portion into other holes, thereby improving workability.

[0161] [6] Furthermore, in the above-described embodiment, in the content of [5] above, the reference movement amount determination step includes a step of calculating the average value of the movement amounts (L1d, L2d) of predetermined hoists (10A, 10B) selected from among a plurality of hoists (10A, 10B, ...) and setting the average value as the reference movement amount L0d.

[0162] In this way, by using a predetermined average value of the movement amount of the hoist 10 to calculate the attitude deviation, the calculation of the attitude deviation becomes easy.

[0163] [7] Furthermore, in the above-described embodiment, in addition to the contents described in either [5] or [6] above, or a combination thereof, the movement amount calculation step includes a step of calculating the acceleration of the payout length L1 (position) of the load chain C1 detected by the position calculation unit 102 (position detection means), and the reference movement amount determination step includes a step of transmitting the acceleration to other hoists 10, and a step of setting the movement amount of the hoist 10 with the maximum acceleration as the reference movement amount.

[0164] In this way, the acceleration of the connecting portion that is lifting and lowering the workpiece W is calculated by the position calculation unit 102 (position detection means) without specifying the hoisting machine 10 in advance. Then, the location that the worker is lifting and lowering can be determined from the magnitude of the acceleration, and the hoisting control of the other hoisting machines 10 can be performed so as to imitate the lifting and lowering of the nearby hoisting machine 10 that the worker is operating.

[0165] 6. Modifications One embodiment of the present invention has been described above, but the present invention can be modified in various other ways, which will be described below.

[0166] In the above embodiment, the linear member is a load chain C1. However, the linear member is not limited to the load chain C1 and may be a wire rope. In this case, the hoist corresponds to a rope hoist.

[0167] 1...hoisting machine system, 10, 10A to 10C...hoisting machine, 20...hoisting machine main body, 21...housing, 30...upper hook, 40...drive motor, 41...encoder, 50...reduction mechanism, 60...brake mechanism, 70...load sheave, 80...upper limit switch, 81...lower limit switch, 90...load sensor (corresponding to part of load detection means), 100...control unit (corresponding to part of motor control means), 101...memory, 102...position calculation unit, 103...tension calculation unit (corresponding to part of load detection means), 104...inertia moment calculation unit, 110...driver (corresponding to part of motor control means) Response), 120...transmitter / receiver, 150...cylinder operating device, 151...operation mode changeover switch, 152...movable grip, 153...displacement sensor, 160...lower hook, 170...chain bucket, 180...operation switch, 181...hoisting switch, 182...lowering switch, 183...mode changeover switch, 184...stop switch, 200...posture control unit, 201...first addition point, 202...first withdrawal point, 203...reference movement amount determination unit, 204...second addition point, 205...total moment of inertia estimator, 206...posture control torque gain adjuster, 207...posture controller, C1...load chain

Claims

1. A hoisting machine system comprising a plurality of hoists, each of which lifts and lowers a workpiece by winding up and down a load chain or rope, wherein each of the hoists comprises: a hoisting means disposed on the main body of the hoisting machine, around which the load chain or rope is wound, and which winds up and down the load chain or rope in response to rotation; a drive motor which generates a driving force for rotating the hoisting means; a motor control means which controls the driving of the drive motor; a load detection means which detects the tension of the load chain or rope and the operating force applied to the load chain or rope when an operator operates the workpiece in the winding up / lowering direction; and a position detection means which detects the position of the load chain or rope; wherein the motor control means is capable of controlled driving in a torque control mode in which the drive motor is driven based on a first torque command value obtained by adding an assist torque which assists the operating force to a holding torque which is capable of maintaining the tension; the motor control means is provided with an attitude control unit that calculates its own movement amount from the position detected by the position detection means, transmits its own movement amount to another hoist, determines a reference movement amount based on its own movement amount and the received movement amount of the other hoist, and calculates an attitude control torque value for controlling the attitude of the work based on the difference between the reference movement amount and its own movement amount; and the motor control means, in the torque control mode, controls the attitude of the work by controlling the drive of the drive motor based on a second torque command value obtained by adding the attitude control torque value to the first torque command value.

2. A hoist system according to claim 1, wherein the attitude control unit calculates the attitude control torque value based on the difference between the reference movement amount and the movement amount of the hoist and all moments of inertia handled by each of the hoists.

3. A hoist system according to claim 1, characterized in that the reference movement amount is the average value of the movement amounts of predetermined hoists selected from among the plurality of hoists.

4. A hoist system according to claim 1, characterized in that the posture control unit calculates the posture control torque value for controlling the posture of the workpiece based on PI control.

5. A control method for a hoisting machine system that includes a plurality of hoists and that raises and lowers a single workpiece by winding up and down a load chain or rope on each hoist, wherein each hoist comprises: hoisting means that is arranged on the main body of the hoisting machine, around which the load chain or rope is wound and that winds up and down the load chain or rope in response to rotation; a drive motor that generates a driving force to rotate the hoisting means; motor control means that controls the drive of the drive motor; load detection means that detects the tension of the load chain or rope and the operating force applied to the load chain or rope when an operator operates the workpiece in the winding up / winding down direction; and position detection means that detects the position of the load chain or rope, wherein the motor control means is capable of controlled driving in a torque control mode that drives the drive motor based on a first torque command value that is the sum of a holding torque that can maintain the tension and an assist torque that assists the operating force, and wherein attitude control that controls the attitude of the workpiece in the torque control mode is possible, and in this attitude control: a movement amount calculation step of calculating a movement amount from the position detected by the position detection means; a reference movement amount determination step of transmitting the movement amount to the other hoisting machines and determining a reference movement amount; an attitude deviation calculation step of calculating a difference between the reference movement amount and the workpiece's own movement amount; an attitude control torque calculation step of calculating an attitude control torque for controlling the attitude of the workpiece based on the difference; and a drive control step of controlling drive of the drive motor based on a second torque command value obtained by adding the attitude control torque to the first torque command value.

6. A control method for a hoist system as set forth in claim 5, wherein the reference movement amount determination step includes a step of calculating an average value of the movement amounts of predetermined hoists selected from among the plurality of hoists, and setting the average value as the reference movement amount.

7. A control method for a hoist system as set forth in claim 5, wherein the movement amount calculation step includes a step of calculating the acceleration of the position detected by the position detection means, and the reference movement amount determination step includes a step of transmitting the acceleration to the other hoists, and a step of setting the movement amount of the hoist with the maximum acceleration as the reference movement amount.

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