JP3086103B2 - Force control device for work machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force control device for a force control work machine, and more particularly, to a force control of a force control work machine for automatically changing a plurality of tools as needed to perform work with force control. Related to the device.

[0002]

2. Description of the Related Art Conventionally, an industrial robot, that is, an automatic working machine having a robot main body (mechanical unit) including a plurality of movable axes, includes a force sensor and a force control calculating unit, and performs the force control by these operations. Various methods have been proposed for performing tasks.

[0003] Generally, in a work involving a force, when a force element in the work is detected by using a force sensor and the work is controlled to a desired state by referring to the detected information, the force sensor determines the force generated in the work, The force due to the weight of the work tool attached prior to the force sensor is combined and detected. In order to accurately detect the force generated only by the work, it is necessary to minimize the influence of the tool weight on the value of the force detected by the force sensor. As a conventional method for minimizing the influence, for example, Japanese Unexamined Patent Publication No. 62-74594
There is a method disclosed in Japanese Patent Publication No.

In the above-mentioned prior art, the weight and center of gravity of a hand (corresponding to a tool) attached to the tip of a force sensor are obtained, and the influence of the hand weight on the detection value of the force sensor is corrected by calculation. A method for performing good force control is proposed. Specifically, after attaching the tool to the industrial robot, a plurality (at least 3
And the detected values of the force in each posture and the detection direction of the force sensor are stored. Using this result, the weight and the position of the center of gravity of the tool are calculated and registered. When performing the work, using the registered values of the weight and the position of the center of gravity and the detection direction of the force sensor at that time, calculate the value expected to be detected by the force sensor with respect to the weight of the tool,
The obtained weight value is subtracted from the actual force detection value. By performing force control using the detected value of the force obtained in this manner, it is possible to satisfactorily perform work requiring force such as deburring.

[0005]

In the prior art including the above-mentioned technology, generally, a plurality of work tools are prepared in advance, and the work tools are exchanged or selected as needed during the work. No consideration is given to what to do, and there is a problem that work using force control can only be performed using one work tool.

SUMMARY OF THE INVENTION An object of the present invention is to provide a working machine which requires force control, a plurality of working tools which are automatically exchanged as necessary and which can be used for any one of the working tools so that automatic work can be smoothly performed. An object of the present invention is to provide a force control device for a control work machine.

[0007]

A force control device for a force control work machine according to the present invention is configured as follows to achieve the above object.

A mechanism having at least one or more movable shafts, force detecting means attached to the tip of the mechanism, work tool changing means mounted on the force detecting means, and work tool changing means The present invention is applied to a force control work machine having any one of a plurality of work tools to be selectively mounted, and generates a control command using force data detected by force detection means, and uses the control command to generate a mechanism. Storage means having force control execution means for controlling the operation of the part and causing a work tool mounted on the mechanism part to perform work, and further storing data relating to at least the weight and the position of the center of gravity of each of the plurality of work tools in advance And when one of the work tools is mounted on the mechanism based on the replacement operation of the work tool replacement means, the data of the weight and the center of gravity corresponding to the mounted work tool are displayed. From the storage means, and sets the force control execution means. The force control execution means corrects the force data detected by the force detection means based on the weight and the center of gravity position data set by the setting means. It is composed of

In the above configuration, preferably, each of the plurality of work tools is assigned a unique number,
It is configured so that data relating to the weight and the position of the center of gravity of the work tool can be designated by a unique number.

Also, a mechanism having at least one or more movable shafts, force detecting means attached to the tip of the mechanism, work tool changing means mounted on the force detecting means, and work tool changing means The present invention is applied to a force control work machine having a plurality of work tools, any one of which is selectively mounted by means, and generates a control command using force data detected by the force detection means, and executes the control command. Has a force control executing means for controlling the operation of the mechanism part and causing a work tool mounted on the mechanism part to perform a work, and a posture control means for controlling the posture of the mechanism part. When multiple postures are taken, the data on the weight and the center of gravity of the work tool mounted on the mechanism is performed using the force data obtained by the force detection means and the posture data obtained by the posture detection means in each posture. Calculating means for, when the operation means has computed data on weight and center of gravity position, configured to have a storage means for storing data relating to weight and center of gravity position for each working tool.

In the above configuration, preferably, the data relating to the weight and the position of the center of gravity of each of the plurality of work tools stored in the storage means is regionally distinguished by a unique number.

In the above configuration, preferably, the storage means also stores information for designating a control point for each work tool.

[0013]

According to the present invention, work involving force control is performed. For example, in a force control work machine having a plurality of various grinders, one of the grinders is selected and mounted, and the work is started. In the case of selecting and replacing another grinder as necessary, a grinder definition mode for specifying each of the plurality of grinders is provided, and a registration area is provided for each tool number predetermined for each grinder. Prepare in storage means. Each registration area stores the weight, the position of the center of gravity, and the control points of the corresponding grinder. In the replacement of the grinder, by specifying the tool number, it is possible to select the force control parameters such as the exact weight and the center of gravity position corresponding to the grinder mounted on the mechanism, and thereby select one of the plurality of grinders Automatic work can be carried out automatically by replacing automatically.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In this embodiment, an industrial robot that automatically performs a deburring operation will be described as an example of a force control work machine that performs an operation requiring force control. FIG. 1 is a diagram showing the configuration of the entire system of the industrial robot. In FIG. 1, reference numeral 1 denotes a robot main body (mechanical unit). The robot body 1 has a six-axis configuration including six movable axes, and is driven by six motors. A force sensor 3, an auto tool changer (hereinafter, referred to as ATC) 4 for exchanging a work tool, and a grinder 5 as a work tool are attached to the tip of the arm 2 of the robot body 1. The force sensor 3 used in this embodiment is, for example, a six-axis sensor type, and can detect a force in each of X, Y, and Z directions and a moment about each of the X, Y, and Z axes. Reference numeral 6 denotes a robot controller, which includes force control means and controls all devices. Reference numeral 7 denotes a playback console (hereinafter referred to as PBC).
This PB is used to start the work of the robot body 1 and switch the mode.
This is done by operating a push button or switch on C7. Reference numeral 8 denotes a programming unit (hereinafter, referred to as PGU) which is a teaching pendant, and is provided with a liquid crystal display device and various push buttons. The operator operates the PGU 8 to manually change the posture of the robot main body 1, instruct position teaching, and input various parameters. 9
Is a tool base for installing a plurality of work tools used for the work and appropriately selected and exchanged according to the work content. On the tool base 9, for example, three types of grinders 10, 11, 12 are placed. Reference numeral 13 denotes a work to be worked, and a deburring work is performed on the work 13. The work 13 is fixed on a work setting table 14. When performing the deburring work on the work 13, in this embodiment, an appropriate grinder is automatically selected from the grinders 5, 10 to 12 according to the progress of the work. Thus, the grinder is automatically replaced during the operation.

Next, the connection relation of devices such as tools will be described with reference to FIG. The ATC 4 includes a contact part 4a and a chuck part 4b. The contact part 4a is a grinder 5,
It is an electrical connection unit for supplying power and operation control signals to any of 10 to 12 mounted on the ATC 4. The grinder mounted on the ATC 4 is electrically connected to the robot controller 6 by a plug-type contact of the contact portion 4a. The on / off operation of the grinder is controlled based on the control operation of the robot controller 6. Chuck part 4b
Is means for mechanically fixing and holding the grinder. When the robot body 1 moves the ATC 4 to the setting position of the grinders 5, 10 to 12 on the tool base 9, and then instructs the chucking part 4b to perform a mounting operation, the grinder is mechanically mounted and the arm tip of the robot body 1 is moved. To the part. In the example shown in FIGS. 1 and 2, the grinder 5 is mounted. Further, as shown in FIG. 2, the robot controller 6 is further electrically connected to a force sensor 3, a PBC 7, and a PGU 8.

Next, referring to FIG.
The internal configuration (hardware configuration) and the configuration added to the robot body 1 will be described.

A CPU 30 is a main central processing unit.
(1) to perform overall device management and characteristic processing of the present invention. Reference numeral 31 denotes a ROM (1) which stores a program describing processing to be performed by the CPU (1) 30 when the power is turned on. Reference numeral 32 denotes a RAM (1) into which various processing programs and teaching data stored in a hard disk (HDD) 37 are loaded.
Performed by The intermediate result of the calculation by the CPU (1) 30 is also stored in the RAM (1) 32. 33 is a timer
(1). The timer (1) 33 interrupts the CPU (1) 30 at regular intervals. 34 is an input / output interface. Through this, the CPU (1) 30
The operation instruction is given to the contact portion 4a and the chuck portion 4b. 3
5 is a communication interface. This communication interface 35 includes two channels. The first channel is for communication with PGU 8 and the second channel is for PBC 7
It is communication with. Information entered in PGU 8 and PBC 7
Information on the button pressed by the user is transmitted to the CPU (1) 30 via the communication interface 35. A hard disk (HD) interface 36 connects the hard disk 37 and the bus 39. 38 is a dual port RAM (DPR). CPU (1) 30 and C
The PU (2) 40 exchanges information via the DPR 38. Reference numeral 47 denotes an A / D converter (ADC).
The A / D converter 47 can perform conversion for six channels. The detection value of the force sensor 3 provided in the robot body 1 is transmitted to the A / A through a low-pass filter (LPF) 48.
It is connected to a D converter 47. A bus 39 connects each device.

Next, reference numeral 40 denotes a CPU (2).
(2) 40 generates a control command based on position and force control calculation processing, and performs servo-related processing related to the operation of the robot body 1. Reference numeral 41 denotes a ROM (2) which stores a program to be executed by the CPU (2) 40. 42 is RAM
(2) The intermediate result of the operation is stored when the CPU (2) 40 executes the program in the ROM (2) 41. 43
Is a timer (2), and the CPU (2) 40
Interrupt In this cycle, the CPU (2) 40 outputs operation commands to the motors (servo motors) M1 to M6 provided on the respective movable axes (joint portions) of the robot body 1. 4
Reference numeral 4 denotes a counter unit, which includes six counters. Each counter of the counter unit 44 is connected to a corresponding one of the encoders E1 to E6 provided at each joint of the robot main body 1, respectively.
By reading the measurement value of the counter unit 44, the CPU (2) 40 can obtain data on the current position and posture of the robot body 1. Reference numeral 45 denotes a D / A converter (DAC), which converts an operation command (current command) for each motor output from the CPU (2) 40 into an analog value. Thereafter, the operation command is amplified by the servo amplifier 46 and given to the six motors M1 to M6.
These motors are driven. A bus 49 connects each device.

The robot body 1 has M1 to M6 at each joint.
Up to six motors, and each of these motors includes a pivot axis, an upper arm axis, a forearm axis,
Drives the rotation axis, bending axis, and twist axis. E for each motor
Encoders 1 to E6 are attached to measure the rotation angle of the motor.

Next, the actual processing performed by the CPU (1) 30 will be described.

FIG. 4 is a flowchart showing the overall processing, which is performed by the CPU (1) 30. When the power is turned on, initialization is performed in the first step 100. In the initialization, necessary programs and data are loaded from the hard disk 37, and each device is initialized.

In the next step 101, the mode changeover switch of the PBC 7 is checked. There are three types of modes, a tool definition mode, a teaching mode, and an automatic operation mode. In the tool definition mode, a tool definition process is performed in step 102. In the teaching mode, in step 103, the teaching of the position of the work location on the work 13 and the teaching of the work command are performed. In the position teaching, the robot body 1 is guided to the position to be taught using the robot guidance button of the PGU 8, and the position is registered by pressing the position teaching button of the PGU 8. In order to teach a work instruction, a menu of the PGU 8 is selected and the prepared instruction is registered. In the automatic operation mode, an automatic operation process is performed in step 104. Next, the processing contents of each mode will be described in detail with reference to the drawings.

The tool definition processing will be described with reference to the flowchart of FIG. First, the tool to be registered is mounted on the tip of the arm 2 of the robot body 1, and the tool number is input (step 110). It is assumed that the tool number is uniquely determined in advance. In this embodiment, "1" to "4" are used as tool numbers for the above-described grinders 5, 10 to 12, respectively. Next, the robot main body 1 is caused to take at least three postures by guidance, and the weight and the center of gravity of the tool mounted on the robot main body 1 are measured. In step 111, the robot body 1 is guided to the first posture. The guidance is performed by operating the robot guidance button of the PGU 8. When the guidance of the first posture is completed,
The force measurement is performed using the force sensor 3 and the force measurement value F1 in the first posture is stored. The force measurement value F1 is represented by a six-dimensional vector. Similarly, the user is guided to the second posture (step 113), the force measurement value F2 in the second posture is stored (step 114), the third posture is guided (step 115), and the force measurement value F3 is calculated. Memorize (Step 11
6). In step 117, using the force measurement values F1, F2, and F3 of the first, second, and third postures and the first, second, and third posture data, the weight and the center of gravity of the mounted tool are determined. Calculate each value. Each posture data is taken in by the encoders E1 to E6 and the counter unit 44 when each posture is taken.

The means for calculating the weight and the position of the center of gravity obtains the weight and the position of the center of gravity of the grinder 5 mounted on the robot body 1 via the force sensor 3 using the force data and the posture data. As the means for calculating the weight and the center of gravity, any means having such a calculating function can be used. For example, as one calculation method for obtaining the weight and the center of gravity, the present inventors have previously described the weight and the center of gravity. Weight and center of gravity position correction device that obtains
279774). In this weight / gravity center position correction device, the weight of the tool used for gravity correction is determined by the vector amount expressed in the base coordinate system, etc., so that it is compared with that calculated by the scalar amount as in the previous calculation method. Then, the installation state of the force control work machine can be inevitably included in the weight expression of the work tool,
This has the advantage that no means or adjustment process is required for the adjustment. That is, since a parameter relating to weight (a value for gravity correction) is obtained by a three-dimensional vector, there is an advantage that the robot main body 1 can cope with any installation state without special instructions.

Next, a tool center point (TCP) is input (step 118). TCP defines a control point of the robot body 1, and represents three-dimensional position and posture.
It is composed of a × 4 matrix. Finally, in step 119, each value obtained by the above calculation is registered in the area corresponding to the tool number, and the hard disk 37 serving as a storage device is registered.
To be stored. In step 120, it is checked whether there is another tool to be registered. If there is another tool, the tool is exchanged and steps 110 to 119 are repeated. In the case of the present embodiment, since the tool is the grinder 5 with the tool number 1 and the other grinders 10 to 12 with the tool numbers 2 to 4 remain, the steps 110 to 119 are sequentially performed for these tools. Then, the weight and the position of the center of gravity are calculated and stored in the hard disk 37.

FIG. 6 shows the contents of the tool registration table.
Reference numeral 125 denotes the entire configuration of the registration table. In this registration table 125, N tools can be registered.
A registration area is provided corresponding to the tool number. In this embodiment, four registration areas of tool numbers 1 to 4 are used. 126 is the tool number 3 in the registration table 125
Is expanded to show the contents. Tool weight is represented by a three-dimensional vector (X to Z)
However, this also represents the relationship between the base coordinate system of the robot body 1 and the direction of gravity. By expressing the three-dimensional vector, the robot body 1 can be operated properly even when used in a ceiling-mounted state or a wall-mounted state. 3 areas for center of gravity of tool, 12 for TCP
Areas are prepared.

FIG. 7 shows an example of a program created by the teaching process.

This program is a program for deburring two places of the work 13 to be worked by using different grinders. This program is executed by automatic operation. The programs are assigned unique numbers, and the robot apparatus of this embodiment can teach 100 programs in all. The program in FIG. 7 is the program taught as the first one. In each program, step No. One instruction can be specified for each.

The instructions used in the program will be described. The tool command used in steps 1 and 17 is the main command of the present invention, and indicates replacement of the tool to be used. With this exchange command, the grinder attached to the arm tip of the robot body 1 is exchanged with the one with the designated tool number. The mov command used in steps 2, 4 and the like is an operation command for the robot body 1,
Thereafter, it instructs to move / operate the robot body 1 to a position such as P001 instructed. The force offset update command used in steps 5 and 20 is
This is a command for removing a temperature drift or the like of the force sensor 5. The grinder on command used in steps 6 and 21 is a rotation start command of the currently mounted grinder, and the grinder off command used in steps 11 and 26 is a rotation end command. The ATCon command used in steps 3 and 16 instructs chucking of the tool, and the ATCoff command used in step 14 is a command for releasing the chuck of the tool. The force control on command used in steps 7 and 22 is a command for shifting the robot main body 1 from the position control state to the force control state, and detailed parameters required for force control according to the condition number specified thereafter. Can be specified. Step 1
The force control off command used in 0, 25 is a command for shifting the robot body 1 from the force control state to the position control state.

The operation of the automatic operation will be described with reference to the flowchart of FIG. First, the PBC 7 is operated to input a program number (step 130). The program of the input program number is stored in the RAM from the hard disk 37.
(1) Load to 32 (step 131). Next, PB
Wait until the start button on C7 is pressed (step 13)
2). When the start button is pressed, the execution step number is set to 1 (step 133). Fetch the instruction of the program specified by the execution step number (step 13
4). The instruction is determined, and the process branches to one of steps 136 to 141 according to the content of the instruction (step 135). If it is a tool command, step 136
Performs tool processing. Figure 9 shows the contents of the tool processing
This will be described later with reference to FIG. If it is a mov instruction, mov processing is performed in step 137. The mov processing is performed by the CPU (1)
30 to perform interpolation processing and force control processing, and
Set to 38. The CPU (2) 40 performs a servo process according to the set command information and outputs a current command to the servo amplifier 4.
Instruct 6 When the operation is completed, the process jumps to step 142 to execute the instruction of the next step number.

If it is a force offset update command, a force offset update process is performed (step 138). CPU (1) 3
0 captures the detection value of the force sensor 3 and outputs the current force sensor 3
Is obtained by calculation and stored as a force offset. Hereinafter, a value obtained by subtracting the force offset value from the force detection value is set as a correct force detection value. When the command is a force control command, a force control process is performed (step 139). In the force control process, after taking out the parameter specified by the condition number, the state shifts to the force control state. In the force control state, the influence of the weight is removed from the detected force value from which the offset has been subtracted using the posture, the weight, and the position of the center of gravity of the tool, and used for control.
If it is a grinder command, grinder processing is performed (step 140). At this time, on or off is instructed via the input / output interface 34 based on on or off instructed after the grinder instruction. A
At the time of a TC instruction, ATC processing is performed (step 14).
1). Here, on or off is specified via the input / output interface 34 based on on or off specified after the ATC instruction. In the case of the END instruction, this processing ends. When an instruction other than the END instruction is executed, 1 is added to the execution step number in step 142,
It repeats from the process from step 134.

The tool processing will be described with reference to the flowchart of FIG. First, it is determined whether or not the currently used tool number is different from the tool number specified by the tool command (step 150). If they are the same, the process ends without doing anything. If they are different, the processing from step 151 onward is performed. First, the weight of the tool is extracted from the registration area of the designated tool number, and is set as the weight area of the tool currently used (step 151). Next, similarly, the position of the center of gravity of the tool is set (step 152). Next, all data related to TCP are set (step 1).
53). With this setting, the CPU (1) 30 will thereafter
It is possible to operate using various parameters of the replaced grinder. Finally, the currently used tool number is rewritten to the designated tool number, and the process is terminated (step 154).

FIG. 10 is a functional block diagram showing a force control device according to the present invention. A plurality of work tools (i.e., grinders 5, 10 to 12) are prepared, and in performing a work in which a grinder is automatically selected and replaced appropriately during the work, the weight of each tool is determined by a tool definition process before the work is started. The position of the center of gravity is determined, and the data of the weight and the position of the center of gravity are stored in the storage unit (tool registration table) 54 under a unique number given to each tool and are prepared.
A program for executing the work is created by the teaching process and stored in a storage unit (not shown). This work program includes instructions for exchanging and using a plurality of tools. In the automatic operation process at the time of executing the work, a work program is called and executed. Consider only execution of instructions related to automatic tool change. Tool selection instruction means 51
, The decoder 52 decodes the instruction, and the processing execution unit 53 executes the decoded contents. The processing execution unit 53 extracts data such as the weight and the center of gravity of the designated work tool from the storage unit 54 based on the unique number, sends the data to the preprocessing unit 55, and performs preprocessing here. Further, a force control command is created by the force control executing means 56 using the preprocessed data, and the work is executed using the replaced tool.

In the above embodiment, a grinder is used as a work tool. However, it goes without saying that the present invention can be implemented with a hand or another work tool.

[0036]

As apparent from the above description, the present invention has the following effects.

A force control device for a working machine that includes a force sensor, generates a control command using force information detected by the force sensor, and causes the work tool to perform a work involving a force, includes a plurality of work tools. Since the compensation data such as the weight and the position of the center of gravity of these work tools are measured in advance and stored in the storage unit, it is possible to perform good force control even in a work performed by automatically changing a plurality of work tools. it can. Further, since the work tools are managed by the tool numbers uniquely assigned, it is easy for the operator to understand, and it is easy to additionally register a new work tool. Furthermore, since parameters relating to weight are calculated and registered in a three-dimensional vector, it is possible to deal with any installation state of the robot body without special instructions. As described above, good force control can be performed even in a force work performed by automatically changing a plurality of work tools.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an example of a system configuration of a force control work machine according to the present invention.

FIG. 2 is a configuration diagram for explaining a connection relationship between devices.

FIG. 3 is a hardware configuration diagram of the robot control device.

FIG. 4 is a flowchart showing an overall process executed by the robot control device.

FIG. 5 is a flowchart illustrating a tool definition process.

FIG. 6 is a diagram for explaining a configuration of a tool registration table.

FIG. 7 is a diagram showing an example of a program created as a result of a teaching process.

FIG. 8 is a flowchart illustrating an automatic driving process.

FIG. 9 is a flowchart illustrating tool processing.

FIG. 10 is a functional block diagram showing a basic configuration of a force control device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Robot main body 2 Arm 3 Force sensor 4 Auto tool changer (AT
C) 5 Grinder 6 Robot controller 7 Playback console (PB
C) 8 Programming unit (PG
U) 9 Tool stand 10-12 Grinder 13 Work

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenjiro Fujii 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Inside the Narashino Plant of Hitachi, Ltd. Sho 62-84991 (JP, A) JP-A-5-116081 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B25J 3/00-3/04 B25J 9/10-9 / 22 B25J 13/00-13/08 B25J 15/04 B25J 19/02-19/06 B23Q 3 / 155,3 / 157 B23Q 15/00-15/28

Claims (5)

(57) [Claims] 1. A mechanism having at least one or more movable shafts, a force detecting means attached to a front end of the mechanism, a work tool exchanging means attached to the force detecting means, and a work tool exchanging means. A force control work machine having a plurality of work tools, any one of which is selectively mounted by the means, and an operation of the mechanism unit by a control command created using force data detected by the force detection means. A force control device having force control execution means for controlling the operation tool, wherein at least data relating to at least the weight and the position of the center of gravity of each of the plurality of work tools is stored in advance; When the two work tools are mounted on the mechanism section, the data of the weight and the position of the center of gravity corresponding to the work tools are taken out from the storage means and Setting means for setting the force control execution means, wherein the force control execution means corrects the force data detected by the force detection means according to the set data of the weight and the position of the center of gravity. Force control work machine force control device. 2. The force control device for a power control work machine according to claim 1, wherein a unique number is assigned to each of the plurality of work tools, and the weight and the position of the center of gravity of the work tool are determined by the unique numbers. A force control device for a force control work machine, wherein the data is specified. 3. A mechanism having at least one or more movable shafts, force detecting means attached to the tip of the mechanism, work tool changing means mounted on the force detecting means, and work tool changing means. A force control work machine having a plurality of work tools, any one of which is selectively mounted by the means, and a control command created by using force data detected by the force detection means. In a force control device having a force control execution unit for controlling an operation and a posture control unit for controlling the posture of the mechanism unit, when the posture control unit causes the mechanism unit to adopt a plurality of postures, Calculating means for calculating the data of the weight and the position of the center of gravity of the work tool mounted on the mechanism using the force data obtained by the force detecting means and the posture data obtained by the posture detecting means; A force control device for a force control work machine, comprising: storage means for storing the data of the weight and the position of the center of gravity for each work tool when the step calculates the data of the position of the weight and the position of the center of gravity. 4. The force control device for a power control work machine according to claim 3, wherein the data of the weight and the position of the center of gravity of each of the plurality of work tools stored in the storage unit are:
A force control device for a force control work machine, wherein the force control device is distinguished regionally by a unique number. 5. The force control device for a force control work machine according to claim 3, wherein information for designating a control point for each work tool is also stored in said storage means. Force control device for control work machine.