Control device and mechanical system

Abstract

This control device comprises: a control unit which performs mass measurement or force control using a torque sensor that detects a torque acting on a link in a machine; and a torque sensor adjustment unit for adjusting the torque sensor by using an external instrument or by using internal data or external data.

Description

[Technical Field]

[0001] The present invention relates to a machine control technology, and more particularly to a control device and a machine system that measure forces acting on a control point of a machine. [Background technology]

[0002] Techniques for controlling the force acting on a control point of a machine such as a robot using a torque sensor that detects the torque acting on the link of the machine, and for measuring the mass of a workpiece held at the control point of the machine, are widely known. To perform such force control or mass measurement, the force acting on the control point is calculated based on the detected value of the torque sensor and the distance from the torque sensor to the control point of the machine.

[0003] When a torque sensor attached to a link of a machine is used, the accuracy of the force acting on the control point of the machine tends to be lower than when a force sensor attached near the control point of the machine is used. This is mainly due to the long distance from the torque sensor to the control point. The farther the control point is from the torque sensor, the greater the force noise becomes when converting the torque sensor detection value into the force acting on the control point. Furthermore, depending on the rigidity of the mechanical parts of the machine, there is a possibility that the force actually generated at the control point will differ from the force calculated by the torque sensor. The following documents, for example, are known as background art related to this application.

[0004] Patent Document 1 describes a method and device for automatically detecting a transformation matrix that shows the relationship between strain voltage and force (force and torque are collectively referred to as "force") in a force sensor attached between the wrist and hand of a robot. The device describes a method in which a workpiece with a known weight and center of gravity is held by the hand, the wrist is swung to assume different postures, and force is calculated from the posture and position of the force sensor detected by an encoder at that time and the weight and center of gravity positions of the workpiece and hand that have been input in advance, and the strain voltage detected by the force sensor is then imported, and a transformation matrix between the calculated force and the imported strain voltage is calculated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 62-237335 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the problems of the prior art, an object of the present invention is to provide a technique for performing force control or mass measurement with high precision using a torque sensor attached to a link of a machine. [Means for solving the problem]

[0007] One aspect of the present disclosure is a machine including a control unit that performs force control or mass measurement using a torque sensor that detects torque acting on a link of a machine, and a torque sensor adjustment unit that adjusts the torque sensor using an external device or internal or external data. The external device includes one of a force sensor attached near a control point of the machine, a workpiece having a known mass, and a visual sensor. A control device is provided. Another aspect of the present disclosure is a machine including a control unit that performs force control or mass measurement using a torque sensor that detects torque acting on a link of a machine, and a torque sensor adjustment unit that sets the adjustment of the torque sensor to be complete when the torque sensor has been adjusted a predetermined number of times or when the result of the torque sensor adjustment has converged. The control unit applies a correction amount of the torque sensor according to the work content of the machine. A control device is provided. Another aspect of the present disclosure is a machine including a torque sensor that detects torque acting on a link, a control unit that performs force control or mass measurement using the torque sensor, and a torque sensor adjustment unit that adjusts the torque sensor using an external device or internal or external data. The external device includes one of a force sensor attached near a control point of the machine, a workpiece having a known mass, and a visual sensor. , provides mechanical systems. [Effects of the Invention]

[0008] According to any one of the aspects of the present disclosure, force control or mass measurement can be performed with high precision using a torque sensor attached to a link of a machine. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1 is a configuration diagram of a mechanical system according to a first embodiment. [Figure 1B] 11 shows a setting screen for force control according to the first embodiment. [Figure 2A] FIG. 10 is a configuration diagram of a mechanical system according to a second embodiment. [Figure 2B] 10 shows a setting screen for force control according to the second embodiment. [Figure 3A] FIG. 10 is a configuration diagram of a mechanical system according to a third embodiment. [Figure 3B] 13 shows a setting screen for force control according to the third embodiment. [Figure 4A] FIG. 10 is a configuration diagram of a mechanical system according to a fourth embodiment. [Figure 4B] 13 shows a setting screen for force control according to the fourth embodiment. [Figure 5A] FIG. 10 is a configuration diagram of a mechanical system according to a fifth embodiment. [Figure 5B] 13 shows a setting screen for force control according to the fifth embodiment. [Figure 6A] FIG. 13 is a configuration diagram of a mechanical system according to a sixth embodiment. [Figure 6B] 13 shows a setting screen for force control according to the sixth embodiment. [Figure 7] FIG. 1 is a block diagram of a mechanical system according to one embodiment. [Figure 8] FIG. 10 is a block diagram of a mechanical system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In each drawing, the same or similar components are assigned the same or similar reference numerals. Furthermore, the embodiments described below do not limit the technical scope and meaning of the terms of the invention described in the claims.

[0011] A mechanical system 1 according to a first embodiment will now be described. Fig. 1A is a configuration diagram of the mechanical system 1 according to the first embodiment. The mechanical system 1 includes a machine 2 and a control device 3 that controls the operation of the machine 2. The mechanical system 1 also includes a teaching device 4 that teaches the operation of the machine 2, although this is not essential.

[0012] Machine 2 is configured as an articulated robot, but is not limited to this, and in other embodiments, it may be configured as other industrial robots such as a single-joint robot, a parallel link robot, or a dual-arm robot. In another embodiment, machine 2 may not be an industrial robot, but may be configured as other types of robots such as a humanoid. Alternatively, in yet another embodiment, machine 2 may not be a robot, but may be configured as other industrial machines such as machine tools, construction machines, or agricultural machines, or other types of machines such as vehicles, aircraft, or rockets.

[0013] The machine 2 includes one or more links 10 to 16 interconnected to one another. The links 11 to 16 are configured as rotary links that rotate about predetermined axes, but are not limited to this, and in other embodiments, may be configured as linear links that move linearly along predetermined axes. The link 10 is, for example, a base fixed in a predetermined position, and the link 11 is, for example, a rotating body supported rotatably relative to the link 10 about a first axis J1. The link 12 is, for example, an upper arm supported rotatably relative to the link 11 about a second axis J2 perpendicular to the first axis J1, and the link 13 is, for example, a forearm supported rotatably relative to the link 12 about a third axis J3 parallel to the second axis J2.

[0014] Links 14 to 16 are a three-axis wrist attached to link 13. Link 14 is a first wrist element supported rotatably relative to link 13, for example, about a fourth axis J4 perpendicular to the third axis J3, link 15 is a second wrist element supported rotatably relative to link 14, for example, about a fifth axis J5 perpendicular to the fourth axis J4, and link 16 is a third wrist element supported rotatably relative to link 15, for example, about a sixth axis J6 perpendicular to the fifth axis J5.

[0015] The machine 2 further includes a tool 17 that is detachably attached to the tip of the machine 2. The tool 17 is configured as a hand tool that holds the workpiece W1, but is not limited to this, and in other embodiments, may be configured as other types of tools such as a welding tool, a screw tightening tool, a deburring tool, a polishing tool, etc. The machine 2 of the first embodiment performs the task of fitting the cylindrical workpiece W1 held by the hand into the concave workpiece W2.

[0016] Although not shown, the machine 2 is equipped with one or more actuators that drive the links 11 to 16 and one or more torque sensors that detect torque acting on the links 11 to 16. The actuators are provided near the joints of the links 11 to 16. The actuators are configured as electric actuators including electric motors, encoders, reducers, etc., but are not limited to this, and in other embodiments, may be configured as other actuators such as hydraulic or pneumatic. The torque sensors are provided at the joints of the links 11 to 16. The torque sensors are configured as strain gauge torque sensors, but are not limited to this, and in other embodiments, may be configured as other torque sensors such as piezoelectric, optical, or capacitive.

[0017] The control device 3 includes a programmable logic controller (PLC) or the like, but is not limited to this, and in other embodiments, may be configured with other types of computers including a processor, memory, input / output interface, etc., connected to each other by a bus. The control device 3 includes a drive circuit that drives the actuator, but in other embodiments, the machine 2 may include a drive circuit that drives the actuator. The control device 3 is connected to the actuator and torque sensor via wire or wireless. The control device 3 sends operation command values ​​to the actuator and receives operation detection values ​​from the actuator. The control device 3 also receives torque detection values ​​from the torque sensor.

[0018] The control device 3 sets various coordinate systems, such as a world coordinate system, a machine coordinate system, a flange coordinate system, a tool coordinate system, a camera coordinate system, and a user coordinate system. These coordinate systems are, for example, Cartesian coordinate systems. For ease of explanation, it is assumed that the control device 3 sets a machine coordinate system C1, a tool coordinate system C2, and a user coordinate system C3. The machine coordinate system C1 is fixed to a reference position of the machine 2, for example, the base, the tool coordinate system C2 is fixed to a reference position of the tool 17, for example, the tool center point (TCP), and the user coordinate system C3 is fixed to an arbitrary position, for example, the workpiece W2.

[0019] The control device 3 sets the control point P, which is the part to be controlled of the machine 2, at the origin (i.e., TCP) of the tool coordinate system C2. Therefore, the position and orientation of the part to be controlled of the machine 2 are expressed by the position and orientation of the tool coordinate system C2 in the machine coordinate system C1. The control device 3 controls the operation of the machine 2 in accordance with an operation program created by the teaching device 4. The operation program includes operation commands for moving the position and orientation of the part to be controlled of the machine 2 to the teaching points that form the operation trajectory of the part to be controlled of the machine 2.

[0020] The teaching device 4 is configured as a teaching operation panel directly attached to the control device 3, but is not limited to this. In other embodiments, the teaching device 4 may be configured as another form of computer device, such as a portable teach pendant, tablet, personal computer, or server device, communicatively connected to the control device 3 via a wired or wireless connection. The teaching device 4 includes a processor, memory, input / output interface, user interface, etc., which are interconnected by a bus, although not shown. The user interface includes an input unit and a display unit, such as a touch panel, display, and keyboard. The teaching device 4 is connected to the control device 3 via a wired or wireless connection. The teaching device 4 includes program creation software, although not shown, that creates an operation program for the machine 2. The teaching device 4 sends the created operation program to the control device 3.

[0021] In the machine system 1 configured as described above, the control device 3 performs force control or mass measurement using torque sensors attached to the links 11 to 16. The control device 3 measures the force acting on the control point P of the machine 2 from the detected value of the torque sensor, and performs force control or mass measurement based on the measurement results. However, due to the long distance from the torque sensor to the control point P, force noise increases when converting the detected value of the torque sensor into the force acting on the control point P. Furthermore, due to the rigidity of the links 11 to 16, there may be a discrepancy between the force actually generated at the control point P and the force acting on the control point P determined by the torque sensor.

[0022] Therefore, in the first embodiment, the torque sensor is adjusted (i.e., calibrated) using a force sensor 50, which is an external device. When adjusting the torque sensor, the force sensor 50 is attached near the control point P of the machine 2 (for example, between the wrist link 16 and the tool 17). Because the force sensor 50 is attached near the control point P of the machine 2, the force acting on the control point P calculated from the detection value of the force sensor 50 is more accurate than the force acting on the control point P calculated from the detection value of the torque sensor. Therefore, the control device 3 uses the force acting on the control point P calculated from the detection value of the force sensor 50 as a reference value and calculates a correction amount for the torque sensor by comparing the force acting on the control point P of the machine 2 calculated from the detection value of the torque sensor with the force acting on the control point P of the machine 2 calculated from the detection value of the force sensor 50. After adjusting the torque sensor, the control device 3 applies the correction amount for the torque sensor to the force acting on the control point P of the machine 2 calculated from the detection value of the torque sensor, and performs force control or mass measurement.

[0023] The force sensor 50 is configured with a six-axis force sensor and detects forces in three axial directions and moments around the three axes, but is not limited to this, and in other embodiments it may be configured with a three-axis force sensor and detect only forces in the three axial directions. In other words, the force sensor 50 is configured with a force sensor on at least one axis depending on the work content of the machine 2.

[0024] When adjusting the torque sensor, the teaching device 4 is used to set parameters such as the work content of the machine 2, the sensor adjustment mode, and the external device used to adjust the torque sensor. Fig. 1B shows a setting screen 40 for force control in the first embodiment. The force control setting screen 40 is displayed on the display unit of the teaching device 4. On the force control setting screen 40, the work content 41 of the machine 2, the sensor type 42 used for force measurement, the sensor adjustment mode 43, the external device for adjustment 44, the user coordinate system number 45, the tool coordinate system number 46, the force action direction 47, etc. are set.

[0025] In the first embodiment, the machine 2 performs an operation of fitting a cylindrical workpiece W1 held by a hand into a concave workpiece W2, and therefore the operation content 41 of the machine 2 is set to "fitting" on the force control setting screen 40. The reason for setting the operation content 41 is that the force acting on the control point P of the machine 2, which is determined from the detection value of the torque sensor, depends on the position and posture of the controlled portion of the machine 2, and therefore the calculated correction amount of the torque sensor also changes depending on the operation content 41 of the machine 2. In other words, the control device 3 adjusts the torque sensor depending on the operation content 41 of the machine 2. Note that, as will be described in the embodiments described later, the operation content 41 of the machine 2 can be switched to one of "fitting," "face matching," "phase matching," "screw tightening," "constant force pressing," "polishing," "deburring," etc.

[0026] The control device 3 uses a torque sensor to measure the force acting on the control point P of the machine 2, so the sensor type 42 used for force measurement is set to "torque sensor" on the force control setting screen 40. Although this is different from the intent of this disclosure, when force control or mass measurement is performed using a force sensor 50, the sensor type 42 used for force measurement is set to "force sensor." As a prerequisite for this disclosure, it is assumed that when the user does not own a force sensor 50 or when the number of force sensors 50 is small compared to the number of machines 2, force control, mass measurement, etc. will be performed using a torque sensor with lower accuracy than the force sensor 50.

[0027] When adjusting the torque sensor, the sensor adjustment mode 43 is set to “enabled” on the force control setting screen 40. While the sensor adjustment mode 43 is set to “enabled,” the control device 3 executes torque sensor correction calculations. When the torque sensor adjustment is complete, the sensor adjustment mode 43 is automatically set to “completed.” Because it is difficult for a user to determine when the torque sensor adjustment is complete and the user may forget to set the sensor adjustment mode 43 to “completed,” it is preferable that the sensor adjustment mode 43 be automatically set to “completed” when, for example, the torque sensor adjustment has been performed a predetermined number of times or when the results (correction amount) of the torque sensor adjustment have converged (when the torque sensor correction amount for each adjustment becomes equal to or less than a predetermined threshold). Note that, if the torque sensor adjustment is not performed, the sensor adjustment mode 43 should be set to “disabled.” While the sensor adjustment mode 43 is set to “disabled,” the control device 3 does not execute torque sensor correction calculations. Although it is not within the scope of the present disclosure, for example, when performing force control or mass measurement using a force sensor 50 attached near a control point P of the machine 2, the sensor adjustment mode 43 may be set to "disabled." Alternatively, the sensor adjustment mode 43 may be switched between "enabled" and "disabled" to compare the accuracy when the torque sensor is adjusted and when the torque sensor is not adjusted.

[0028] In the first embodiment, a force sensor 50 is used as the external device used to adjust the torque sensor, and therefore the external device for adjustment 44 is set to "force sensor" on the force control setting screen 40. As will be described in the embodiments described later, the external device for adjustment 44 can be switched to any one of "force sensor", "workpiece with known mass", "visual sensor", etc.

[0029] Furthermore, in the first embodiment, a user coordinate system C3 having a user coordinate system number of "0" and a tool coordinate system C2 having a tool coordinate system number of "1" are used, so on the force control setting screen 40, the user coordinate system number 45 is set to "0" and the tool coordinate system number 46 is set to "1".

[0030] Furthermore, in the first embodiment, the force acting direction when fitting the cylindrical workpiece W1 into the concave workpiece W2 is the -Z axis direction of the tool coordinate system C2, so the force acting direction 47 is set to the -Z axis direction of the "tool" coordinate system on the force control setting screen 40. Note that when setting the force acting direction in the -Z axis direction of the user coordinate C3, it is advisable to set the force acting direction 47 to the -Z axis direction of the "user" coordinate system.

[0031] After setting up the force control as described above, the machine 2 uses the force sensor 50 to fit the cylindrical workpiece W1 into the concave workpiece W2, and the control device 3 records the time series data of the detection values ​​of the force sensor 50 and the time series data of the detection values ​​of the torque sensor during the fitting operation as internal data in memory. After the fitting operation is completed, the control device 3 calculates the correction amount for the torque sensor based on the internal data recorded in memory. In other words, the control device 3 adjusts the torque sensor.

[0032] An example of a method for calculating the correction amount of the torque sensor will be described below. The calculation process for the correction amount of the torque sensor includes (1) a calculation process for converting the detection value of the torque sensor into a force acting on the control point P of the machine 2, and (2) a calculation process for calculating the correction amount of the torque sensor by comparing the force acting on the control point P obtained from the detection value of the torque sensor with the force acting on the control point P obtained from the detection value of the force sensor 50.

[0033] First, we will explain (1) an example of the calculation process for converting the detection value of the torque sensor into a force acting on the control point P of the machine 2. The relational expression between the detection value bi of the i-th axis torque sensor and the force acting on the control point P of the machine 2 (force F and moment M in this example) is expressed as follows, for example.

[0034]

number

[0035] That is, the following relational expression holds for the ith axis torque sensor:

[0036]

number

[0037]

number

[0038] Equation 3 can be summarized as a determinant as follows:

[0039]

number

[0040] The six unknowns, force vector F and moment vector M, are found from the six simultaneous equations in Equation 4. As a result, the detection value of the torque sensor is converted into a force acting on control point P (force F and moment M in this example).

[0041] Next, we will explain an example of (2) a calculation process for calculating the torque sensor correction amount by comparing the force acting on control point P obtained from the detection value of the torque sensor with the force acting on control point P obtained from the detection value of the force sensor 50. The calculation formulas for the torque sensor correction amount (force correction amount CF and moment correction amount CM in this example) are expressed as follows:

[0042]

number

[0043] The correction amount for the torque sensor is calculated in this manner. Note that the correction amount for the torque sensor is calculated as an average value obtained by averaging the correction amounts obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor over the entire fitting operation, but this is not limited to this, and in other embodiments, the correction amount obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor may be calculated as an average value obtained by averaging the correction amounts obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor for each predetermined operation section during the fitting operation or for each predetermined time interval during the fitting operation.

[0044] The calculated correction amount of the torque sensor is recorded as internal data in the memory of the control device 3. This completes the adjustment (calibration process) of the torque sensor. At this time, the teaching device 4 switches the sensor adjustment mode 43 to "Complete" on the force control setting screen 40 shown in FIG. 1B.

[0045] After adjusting the torque sensor, the force sensor 50 is removed from the machine 2. The removed force sensor 50 can be reused in another machine. That is, the force sensor 50 may be used in another machine to perform force control, mass measurement, etc., or the force sensor 50 may be used as an external device in another machine to perform adjustment of the torque sensor and then be used to perform force control, mass measurement, etc.

[0046] In subsequent tasks, the machine 2 uses the torque sensor to fit another cylindrical workpiece W1 into another concave workpiece W2, and the control device 3 performs force control with high precision by applying the result of torque sensor adjustment (correction amount) to the force acting on the control point P obtained from the detected value of the torque sensor. In other words, the control device 3 can perform force control with approximately the same precision as the force sensor 50.

[0047] An example of a method for applying the torque sensor correction amount will be described below. The process for applying the torque sensor correction amount includes (3) a calculation process for converting the torque sensor detection value into a force acting on the control point P of the machine 2, and (4) a calculation process for applying the torque sensor correction amount to the force acting on the control point P before correction, which is calculated from the torque sensor detection value. Note that the calculation process (3) is the same as the calculation process (1) described above, so a description thereof will be omitted.

[0048] (4) An example of calculation processing for applying torque sensor correction amounts to the forces acting on control point P before correction, which are obtained from the torque sensor detection values, will be described. As expressed in the following formula, the forces acting on control point P before correction, which are obtained from the torque sensor detection values ​​(force F1t and moment M1t in this example), multiplied by the torque sensor correction amounts (force correction amounts CF and moment correction amounts CM in this example) is used as the forces acting on control point P after correction (force F2t and moment M2t in this example).

[0049]

number

[0050] In this manner, the torque sensor correction amount is applied. Note that, although a single torque sensor correction amount is applied throughout the entire fitting operation, the present invention is not limited to this, and in other embodiments, a single torque sensor correction amount may be applied for each predetermined operation section during the fitting operation or for each predetermined time interval during the fitting operation.

[0051] Furthermore, in the first embodiment, the torque sensor is adjusted using the detection value of the force sensor 50 during the fitting operation, but in other embodiments, the torque sensor may be adjusted using the detection value of the force sensor 50 during one of the phase alignment operation, the screw tightening operation, and the constant force pressing operation.

[0052] The mechanical system 1 of the second embodiment will be described below. Fig. 2A is a configuration diagram of the mechanical system 1 of the second embodiment. The configuration of the mechanical system 1 of the second embodiment is the same as the configuration of the mechanical system 1 of the first embodiment, so a description thereof will be omitted. In the second embodiment, the torque sensor is also adjusted (i.e., calibration processing) using a force sensor 50, which is an external device, but the machine 2 of the second embodiment differs from the first embodiment in that it performs the task of aligning the bottom surface of a cylindrical workpiece W1 held by a hand with the surface of an object.

[0053] When adjusting the torque sensor, the teaching device 4 is used to set parameters such as the work content of the machine 2, the sensor adjustment mode, and the external device used to adjust the torque sensor. Fig. 2B shows a setting screen 40 for force control in the second embodiment. In the second embodiment, the machine 2 performs the work of aligning the bottom surface of a cylindrical workpiece W1 held by its hand with the surface of an object, so on the setting screen 40 for force control, the work content 41 of the machine 2 is set to "face alignment."

[0054] Because the control device 3 uses a torque sensor to measure the force acting on the control point P of the machine 2, the sensor type 42 used for force measurement is set to “torque sensor” on the force control setting screen 40. When adjusting the torque sensor, the sensor adjustment mode 43 is set to “enabled” on the force control setting screen 40. While the sensor adjustment mode 43 is set to “enabled,” the control device 3 executes torque sensor correction calculations. When the torque sensor adjustment is complete, the sensor adjustment mode 43 is automatically set to “completed.” Because it is difficult for a user to determine when the torque sensor adjustment is complete and there is a possibility that the user may forget to set the sensor adjustment mode 43 to “completed,” the sensor adjustment mode 43 may be automatically set to “completed” after the torque sensor adjustment has been performed a predetermined number of times or when the results (correction amount) of the torque sensor adjustment have converged (when the torque sensor correction amount for each adjustment falls below a predetermined threshold). If the torque sensor adjustment is not performed, the sensor adjustment mode 43 may be set to “disabled.” In the second embodiment, a force sensor 50 is used as an external device used to adjust the torque sensor, so on the force control setting screen 40, the external device for adjustment 44 is set to "force sensor".

[0055] In addition, in the second embodiment, a user coordinate system C3 having a user coordinate system number of "0" and a tool coordinate system C2 having a tool coordinate system number of "1" are used, and therefore, on the force control setting screen 40, the user coordinate system number 45 is set to "0" and the tool coordinate system number 46 is set to "1." Furthermore, in the second embodiment, the direction of force action when matching the bottom surface of the cylindrical workpiece W1 to the target object is the -Z axis direction of the user coordinate system C3, and therefore, on the force control setting screen 40, the force action direction 47 is set to the -Z axis direction of the "user" coordinate system.

[0056] After setting up force control as described above, the machine 2 uses the force sensor 50 to perform the operation of surface-matching the bottom surface of the cylindrical workpiece W1 to the target object, and the control device 3 records the time-series data of the detection values ​​of the force sensor 50 and the time-series data of the detection values ​​of the torque sensor during the surface-matching operation in memory as internal data. After the surface-matching operation is completed, the control device 3 calculates the correction amount for the torque sensor based on the internal data recorded in memory. In other words, the control device 3 adjusts the torque sensor.

[0057] The calculation process for the torque sensor correction amount is the same as the calculation processes (1) and (2) in the first embodiment, and therefore description thereof will be omitted. The torque sensor correction amount is calculated as an average value obtained by averaging the correction amounts obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor over the entire surface matching work, but is not limited to this, and in other embodiments, the correction amount obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor may be calculated as an average value obtained by averaging for each predetermined motion section during the surface matching work or for each predetermined time interval during the surface matching work.

[0058] The calculated correction amount of the torque sensor is recorded as internal data in the memory of the control device 3. This completes the adjustment (calibration process) of the torque sensor. At this time, the teaching device 4 automatically switches the sensor adjustment mode 43 to "Complete" on the force control setting screen 40 shown in FIG. 2B.

[0059] After adjusting the torque sensor, the force sensor 50 is removed from the machine 2. The removed force sensor 50 can be reused in another machine. That is, the force sensor 50 may be used in another machine to perform force control, mass measurement, etc., or the force sensor 50 may be used as an external device in another machine to perform adjustment of the torque sensor and then be used to perform force control, mass measurement, etc.

[0060] In subsequent tasks, the machine 2 uses the torque sensor to align the bottom surface of another cylindrical workpiece W1 with the target object, and the control device 3 performs highly accurate force control by applying the torque sensor adjustment result (correction amount) to the force acting on the control point P obtained from the torque sensor detection value. In other words, the control device 3 can perform force control with roughly the same accuracy as the force sensor 50.

[0061] The method for applying the torque sensor correction amount is the same as the calculation processes (3) and (4) in the first embodiment, and therefore will not be described here. Although a single torque sensor correction amount is applied throughout the entire surface matching operation, this is not limiting, and in other embodiments, a single correction amount may be applied for each predetermined operation section during the surface matching operation or for each predetermined time interval during the surface matching operation.

[0062] The machine system 1 of the third embodiment will be described below. Fig. 3A is a configuration diagram of the machine system 1 of the third embodiment. The configuration of the machine system 1 of the third embodiment is the same as the configuration of the machine system 1 of the first embodiment, so a description thereof will be omitted. In the third embodiment, the torque sensor is also adjusted (i.e., calibration processing) using a force sensor 50, which is an external device, but the machine 2 of the third embodiment differs from the first embodiment in that it measures the mass of the workpiece W1 held by the hand while transporting the workpiece W1 from one position to another.

[0063] When adjusting the torque sensor, the teaching device 4 is used to set parameters such as the work content of the machine 2, the sensor adjustment mode, and the external device used to adjust the torque sensor. Fig. 3B shows a setting screen 40 for force control according to the third embodiment. In the third embodiment, the machine 2 performs the work of measuring the mass of the workpiece W1, so the work content 41 of the machine 2 is set to "mass measurement" on the setting screen 40 for force control.

[0064] Because the control device 3 uses a torque sensor to measure the force acting on the control point P of the machine 2, the sensor type 42 used for force measurement is set to “torque sensor” on the force control setting screen 40. When adjusting the torque sensor, the sensor adjustment mode 43 is set to “enabled” on the force control setting screen 40. While the sensor adjustment mode 43 is set to “enabled,” the control device 3 executes torque sensor correction calculations. When the torque sensor adjustment is complete, the sensor adjustment mode 43 is automatically set to “completed.” Because it is difficult for a user to determine when the torque sensor adjustment is complete and there is a possibility that the user may forget to set the sensor adjustment mode 43 to “completed,” the sensor adjustment mode 43 may be automatically set to “completed” after the torque sensor adjustment has been performed a predetermined number of times or when the results (correction amount) of the torque sensor adjustment have converged (when the torque sensor correction amount for each adjustment falls below a predetermined threshold). If the torque sensor adjustment is not performed, the sensor adjustment mode 43 may be set to “disabled.” In the third embodiment, a force sensor 50 is used as an external device used to adjust the torque sensor, so on the force control setting screen 40, the external device for adjustment 44 is set to "force sensor".

[0065] Furthermore, in the third embodiment, a user coordinate system C3 with a user coordinate system number of "0" and a tool coordinate system C2 with a tool coordinate system number of "1" are used, and therefore the user coordinate system number 45 is set to "0" and the tool coordinate system number 46 is set to "1" on the force control setting screen 40. Furthermore, although not essential in the third embodiment, if the direction of force action when measuring the mass of the workpiece W1 is the -Z axis direction of the tool coordinate system C2, the force action direction 47 is set to the -Z axis direction of the "tool" coordinate system on the force control setting screen 40.

[0066] When force control is set as described above, machine 2 uses force sensor 50 to measure the mass of workpiece W1 held by its hand while transporting the workpiece W1 from one position to another, and control device 3 records the time series data of the detected values ​​of force sensor 50 and the time series data of the detected values ​​of the torque sensor during the mass measurement operation as internal data in memory. After the mass measurement operation is completed, control device 3 calculates the correction amount for the torque sensor based on the internal data recorded in memory. In other words, control device 3 adjusts the torque sensor.

[0067] The calculation process for the torque sensor correction amount is the same as the calculation processes (1) and (2) in the first embodiment, and therefore will not be described here. The torque sensor correction amount is calculated as an average value obtained by averaging the correction amounts obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor over the entire mass measurement operation, but is not limited to this. In other embodiments, the correction amount obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor may be calculated as an average value obtained by averaging the correction amounts obtained for each predetermined operation section during the mass measurement operation or for each predetermined time interval during the mass measurement operation.

[0068] The calculated correction amount of the torque sensor is recorded as internal data in the memory of the control device 3. This completes the adjustment (calibration process) of the torque sensor. At this time, the teaching device 4 switches the sensor adjustment mode 43 to "Complete" on the force control setting screen 40 shown in FIG. 3B.

[0069] After adjusting the torque sensor, the force sensor 50 is removed from the machine 2. The removed force sensor 50 can be reused in another machine. That is, the force sensor 50 may be used in another machine to perform force control, mass measurement, etc., or the force sensor 50 may be used as an external device in another machine to perform adjustment of the torque sensor and then be used to perform force control, mass measurement, etc.

[0070] In subsequent tasks, the machine 2 will use the torque sensor to measure the mass of another workpiece W1 held by its hand while transporting the workpiece W1 from one position to another, and the control device 3 will perform highly accurate mass measurements by applying the torque sensor adjustment results (correction amount) to the force acting on the control point P determined from the torque sensor detection value. In other words, the control device 3 can perform mass measurements with roughly the same accuracy as the force sensor 50.

[0071] The method for applying the torque sensor correction amount is the same as the calculation processes (3) and (4) in the first embodiment, and therefore will not be described here. Although a single torque sensor correction amount is applied throughout the entire mass measurement operation, this is not limiting, and in other embodiments, a single correction amount may be applied for each predetermined operation section during the mass measurement operation or for each predetermined time interval during the mass measurement operation.

[0072] The mechanical system 1 of the fourth embodiment will be described below. Fig. 4A is a configuration diagram of the mechanical system 1 of the third embodiment. The configuration of the mechanical system 1 of the fourth embodiment is generally the same as the configuration of the mechanical system 1 of the third embodiment, but differs from the third embodiment in that, instead of a force sensor 50, a workpiece 51 with a known mass is used as an external device to adjust the torque sensor (i.e., calibration processing).

[0073] When adjusting the torque sensor, the teaching device 4 is used to set parameters such as the work content of the machine 2, the sensor adjustment mode, and the external device used to adjust the torque sensor. Fig. 4B shows a setting screen 40 for force control according to the fourth embodiment. In the fourth embodiment, the machine 2 performs a task of measuring the mass of the workpiece 51, so the work content 41 of the machine 2 is set to "mass measurement" on the setting screen 40 for force control.

[0074] Because the control device 3 uses a torque sensor to measure the force acting on the control point P of the machine 2, the sensor type 42 used for force measurement is set to “torque sensor” on the force control setting screen 40. When adjusting the torque sensor, the sensor adjustment mode 43 is set to “enabled” on the force control setting screen 40. While the sensor adjustment mode 43 is set to “enabled,” the control device 3 executes torque sensor correction calculations. When the torque sensor adjustment is complete, the sensor adjustment mode 43 is automatically set to “completed.” Because it is difficult for a user to determine when the torque sensor adjustment is complete and there is a possibility that the user may forget to set the sensor adjustment mode 43 to “completed,” the sensor adjustment mode 43 may be automatically set to “completed” after the torque sensor adjustment has been performed a predetermined number of times or when the results (correction amount) of the torque sensor adjustment have converged (when the torque sensor correction amount for each adjustment falls below a predetermined threshold). If the torque sensor adjustment is not performed, the sensor adjustment mode 43 may be set to “disabled.” In the fourth embodiment, a workpiece 51 with a known mass is used as the external device used to adjust the torque sensor, so the external device for adjustment 44 is set to "workpiece with known mass" on the force control setting screen 40. Also, the mass of the workpiece 51 is set ("15 kg" in this example).

[0075] In addition, in the fourth embodiment, a user coordinate system C3 with a user coordinate system number of "0" and a tool coordinate system C2 with a tool coordinate system number of "1" are used, so the user coordinate system number 45 is set to "0" and the tool coordinate system number 46 is set to "1" on the force control setting screen 40. Furthermore, although not essential, in the fourth embodiment, if the direction of force action when measuring the mass of the workpiece 51 is the -Z axis direction of the tool coordinate system C2, the force action direction 47 is set to the -Z axis direction of the "tool" coordinate system on the force control setting screen 40.

[0076] When force control is set as described above, machine 2 uses the torque sensor to measure the mass of workpiece W1 held by its hand while transporting the workpiece W1 from one position to another, and control device 3 records the time-series data of the torque sensor's detected values ​​during the mass measurement operation as internal data in memory. After the mass measurement operation is completed, control device 3 calculates the correction amount for the torque sensor based on the internal data recorded in memory. In other words, control device 3 adjusts the torque sensor.

[0077] The calculation process for the torque sensor correction amount includes (1) a calculation process for converting the torque sensor detection value into a force acting on the control point P of the machine 2, and (2) a calculation process for calculating the torque sensor correction amount by comparing the force acting on the control point P obtained from the torque sensor detection value with the known mass of the workpiece 51. The calculation process (1) in the fourth embodiment is the same as the calculation process (1) in the first embodiment, and therefore a description thereof will be omitted.

[0078] (2) An example of a calculation process will be described below for calculating the torque sensor correction amount by comparing the force acting on control point P determined from the torque sensor detection value with the known mass of workpiece 51. The calculation formula for the torque sensor correction amount (in this example, force correction amount CF and moment correction amount CM) is expressed as follows:

[0079]

number

[0080] The correction amount for the torque sensor is calculated in this manner. Note that the correction amount for the torque sensor is calculated as an average value obtained by averaging the correction amounts found from the time-series data of the detection values ​​of the torque sensor and the force sensor over the entire mass measurement operation, but this is not limited to this, and in other embodiments, the correction amount found from the time-series data of the detection values ​​of the torque sensor and the force sensor may be calculated as an average value obtained by averaging the correction amounts found from the time-series data of the detection values ​​of the torque sensor and the force sensor for each predetermined operation section during the mass measurement operation or for each predetermined time interval during the mass measurement operation.

[0081] The calculated correction amount of the torque sensor is recorded as internal data in the memory of the control device 3. This completes the adjustment (calibration process) of the torque sensor. At this time, the teaching device 4 switches the sensor adjustment mode 43 to "Complete" on the force control setting screen 40 shown in FIG. 4B.

[0082] After adjusting the torque sensor, the workpiece 51 with a known mass can be used in another machine. In other words, after adjusting the torque sensor using the workpiece 51 with a known mass as an external device in another machine, force control, mass measurement, etc. can be performed using the torque sensor.

[0083] In subsequent tasks, the machine 2 will use the torque sensor to measure the mass of another workpiece W1 held by its hand while transporting the workpiece W1 from one position to another, and the control device 3 will perform highly accurate mass measurements by applying the torque sensor adjustment results (correction amount) to the force acting on the control point P determined from the torque sensor detection value. In other words, the control device 3 can perform mass measurements with roughly the same accuracy as the force sensor 50.

[0084] The method for applying the torque sensor correction amount is the same as the calculation processes (3) and (4) in the first embodiment, and therefore will not be described here. Although a single torque sensor correction amount is applied throughout the entire mass measurement operation, this is not limiting, and in other embodiments, a single correction amount may be applied for each predetermined operation section during the mass measurement operation or for each predetermined time interval during the mass measurement operation.

[0085] The following describes a mechanical system 1 according to the fifth embodiment. Fig. 5A is a configuration diagram of the mechanical system 1 according to the fifth embodiment. The configuration of the mechanical system 1 according to the fifth embodiment is the same as the configuration of the mechanical system 1 according to the first embodiment, and therefore a description thereof will be omitted. In the fifth embodiment, the torque sensor is also adjusted (i.e., calibration processing) using a force sensor 50, which is an external device, but the machine 2 according to the fifth embodiment differs from the first embodiment in that it performs the task of polishing the side surface of a workpiece W1 using a polishing tool.

[0086] When adjusting the torque sensor, the teaching device 4 is used to set parameters such as the work content of the machine 2, the sensor adjustment mode, and the external device used to adjust the torque sensor. Fig. 5B shows a setting screen 40 for force control according to the fifth embodiment. In the fifth embodiment, the machine 2 performs the work of grinding the side surface of the workpiece W1 with a grinding tool, and therefore the work content 41 of the machine 2 is set to "grinding" on the setting screen 40 for force control.

[0087] Because the control device 3 uses a torque sensor to measure the force acting on the control point P of the machine 2, the sensor type 42 used for force measurement is set to “torque sensor” on the force control setting screen 40. When adjusting the torque sensor, the sensor adjustment mode 43 is set to “enabled” on the force control setting screen 40. While the sensor adjustment mode 43 is set to “enabled,” the control device 3 executes torque sensor correction calculations. When the torque sensor adjustment is complete, the sensor adjustment mode 43 is automatically set to “completed.” Because it is difficult for a user to determine when the torque sensor adjustment is complete and there is a possibility that the user may forget to set the sensor adjustment mode 43 to “completed,” the sensor adjustment mode 43 may be automatically set to “completed” after the torque sensor adjustment has been performed a predetermined number of times or when the results (correction amount) of the torque sensor adjustment have converged (when the torque sensor correction amount for each adjustment falls below a predetermined threshold). If the torque sensor adjustment is not performed, the sensor adjustment mode 43 may be set to “disabled.” In the fifth embodiment, a force sensor 50 is used as an external device used to adjust the torque sensor, so on the force control setting screen 40, the external device for adjustment 44 is set to "force sensor".

[0088] Moreover, in the fifth embodiment, a user coordinate system C3 having a user coordinate system number of "0" and a tool coordinate system C2 having a tool coordinate system number of "1" are used, and therefore, on the force control setting screen 40, the user coordinate system number 45 is set to "0" and the tool coordinate system number 46 is set to "1." Furthermore, in the fifth embodiment, the direction of force action when polishing the side surface of the workpiece W1 is the X-axis direction of the tool coordinate system C2, and therefore, on the force control setting screen 40, the force action direction 47 is set to the "X" axis direction of the "tool" coordinate system.

[0089] After the force control settings are made as described above, the machine 2 uses the force sensor 50 to polish the side surface of the workpiece W1, and the control device 3 records the time series data of the detected values ​​of the force sensor 50 and the time series data of the detected values ​​of the torque sensor during the polishing operation in memory as internal data. After the polishing operation is completed, the control device 3 calculates the correction amount for the torque sensor based on the internal data recorded in memory. In other words, the control device 3 adjusts the torque sensor.

[0090] The calculation process for the torque sensor correction amount is the same as the calculation processes (1) and (2) in the first embodiment, and therefore description thereof will be omitted. The torque sensor correction amount is calculated as an average value obtained by averaging the correction amounts obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor over the entire sanding operation, but is not limited to this, and in other embodiments, the correction amount obtained from the time-series data of the detection values ​​of the torque sensor and the force sensor may be calculated as an average value obtained by averaging for each predetermined operation section during the sanding operation or for each predetermined time interval during the sanding operation.

[0091] The calculated correction amount of the torque sensor is recorded as internal data in the memory of the control device 3. This completes the adjustment (calibration process) of the torque sensor. At this time, the teaching device 4 switches the sensor adjustment mode 43 to "Complete" on the force control setting screen 40 shown in FIG. 2B.

[0092] After adjusting the torque sensor, the force sensor 50 is removed from the machine 2. The removed force sensor 50 can be reused in another machine. That is, the force sensor 50 may be used in another machine to perform force control, mass measurement, etc., or the force sensor 50 may be used as an external device in another machine to perform adjustment of the torque sensor and then be used to perform force control, mass measurement, etc.

[0093] In subsequent tasks, the machine 2 uses the torque sensor to polish the side surface of another workpiece W1, and the control device 3 performs highly accurate force control by applying the result of torque sensor adjustment (correction amount) to the force acting on the control point P calculated from the detected value of the torque sensor. In other words, the control device 3 can perform force control with roughly the same accuracy as the force sensor 50.

[0094] The method for applying the torque sensor correction amount is the same as the calculation processes (3) and (4) in the first embodiment, and therefore will not be described here. Although a single torque sensor correction amount is applied throughout the entire grinding operation, this is not limiting, and in other embodiments, a single correction amount may be applied for each predetermined operating section during the grinding operation or for each predetermined time interval during the grinding operation.

[0095] A mechanical system 1 according to the sixth embodiment will be described below. Fig. 6A is a configuration diagram of the mechanical system 1 according to the sixth embodiment. The configuration of the mechanical system 1 according to the sixth embodiment is generally the same as that of the mechanical system 1 according to the fifth embodiment, but differs from the fifth embodiment in that a visual sensor 52, rather than a force sensor 50, is used as an external device to adjust the torque sensor (i.e., calibration processing). The machine 2 according to the sixth embodiment also differs from the fifth embodiment in that it uses a deburring tool to remove burrs from the side surface of the workpiece W1.

[0096] When adjusting the torque sensor, the visual sensor 52 is installed near the control point P of the machine 2, for example, at a fixed position different from the machine 2. The control device 3 then acquires a post-deburring image of the deburring portion of the workpiece W1 from the visual sensor 52, and calculates a correction amount for the torque sensor by comparing the actual amount of deburring obtained from the pre-deburring image and the post-deburring image with the target amount of deburring. The control device 3 uses the calculated torque sensor correction amount to correct the force acting on the control point P of the machine 2 obtained from the detection value of the torque sensor, and performs force control, mass measurement, etc.

[0097] The visual sensor 52 is a three-dimensional visual sensor that captures three-dimensional images. The actual amount of deburring is calculated by subtracting the pre-deburring image from the post-deburring image. The target amount of deburring is recorded in the memory of the control device 3 as internal data.

[0098] When adjusting the torque sensor, the teaching device 4 is used to set parameters such as the work content of the machine 2, the sensor adjustment mode, and the external device used to adjust the torque sensor. Fig. 6B shows a setting screen 40 for force control according to the sixth embodiment. In the sixth embodiment, the machine 2 performs the work of removing burrs from the side surface of the workpiece W1 using a deburring tool, so on the setting screen 40 for force control, the work content 41 of the machine 2 is set to "deburring."

[0099] Because the control device 3 uses a torque sensor to measure the force acting on the control point P of the machine 2, the sensor type 42 used for force measurement is set to “torque sensor” on the force control setting screen 40. When adjusting the torque sensor, the sensor adjustment mode 43 is set to “enabled” on the force control setting screen 40. While the sensor adjustment mode 43 is set to “enabled,” the control device 3 executes torque sensor correction calculations. When the torque sensor adjustment is complete, the sensor adjustment mode 43 is automatically set to “completed.” Because it is difficult for a user to determine when the torque sensor adjustment is complete and there is a possibility that the user may forget to set the sensor adjustment mode 43 to “completed,” the sensor adjustment mode 43 may be automatically set to “completed” after the torque sensor adjustment has been performed a predetermined number of times or when the results (correction amount) of the torque sensor adjustment have converged (when the torque sensor correction amount for each adjustment falls below a predetermined threshold). If the torque sensor adjustment is not performed, the sensor adjustment mode 43 may be set to “disabled.” In the sixth embodiment, a visual sensor 52 is used as the external device used to adjust the torque sensor, so on the force control setting screen 40, the external device for adjustment 44 is set to "visual sensor".

[0100] Furthermore, in the sixth embodiment, a user coordinate system C3 having a user coordinate system number of "0" and a tool coordinate system C2 having a tool coordinate system number of "1" are used, and therefore, on the force control setting screen 40, the user coordinate system number 45 is set to "0" and the tool coordinate system number 46 is set to "1." Furthermore, in the sixth embodiment, the direction of force action when deburring the side surface of the workpiece W1 is the X-axis direction of the user coordinate system C3, and therefore, on the force control setting screen 40, the force action direction 47 is set to the X-axis direction of the "user" coordinate system.

[0101] After the force control settings are made as described above, the machine 2 uses the visual sensor 52 to deburr the side surface of the workpiece W1, and the control device 3 records the time-series data of the images acquired by the visual sensor 52 from before the deburring operation to after the deburring operation as internal data in memory. After the deburring operation is completed, the control device 3 calculates the correction amount for the torque sensor based on the internal data recorded in memory. In other words, the control device 3 adjusts the torque sensor.

[0102] An example of a method for calculating the correction amount of the torque sensor will be described below. The calculation process for the correction amount of the torque sensor includes (1) a calculation process for calculating the actual amount of removal after deburring from the pre-deburring image and the post-deburring image using the visual sensor 52, and (2) a calculation process for calculating the correction amount of the torque sensor by comparing the actual amount of removal obtained from the image of the visual sensor 52 with a target amount of removal recorded in advance in memory. The correction amount C of the torque sensor can be calculated, for example, using the following formula.

[0103]

number

[0104] The correction amount of the torque sensor is calculated in this manner. Note that the correction amount of the torque sensor is calculated as an average value obtained by averaging the correction amounts obtained from the time-series data of images from the visual sensor 52 over the entire deburring operation, but is not limited to this, and in other embodiments, the correction amount obtained from the time-series data of images from the visual sensor 52 may be calculated as an average value obtained by averaging the correction amounts obtained for each predetermined operation section during the deburring operation or for each predetermined time interval during the deburring operation.

[0105] The calculated correction amount of the torque sensor is recorded as internal data in the memory of the control device 3. This completes the adjustment (calibration process) of the torque sensor. At this time, the teaching device 4 switches the sensor adjustment mode 43 to "Complete" on the force control setting screen 40 shown in FIG. 6B.

[0106] After adjusting the torque sensor, the visual sensor 52 is removed from its fixed position. The removed visual sensor 52 can be reused in another machine. That is, the visual sensor 52 may be used in another machine to perform force control, mass measurement, etc., or the visual sensor 52 may be used as an external device in another machine to adjust the torque sensor, and then the torque sensor may be used to perform force control, mass measurement, etc.

[0107] In subsequent tasks, the machine 2 will use the torque sensor to remove burrs from the side of another workpiece W1, and the control device 3 will perform highly accurate force control by applying the torque sensor adjustment results (correction amount) to the force acting on the control point P determined from the torque sensor detection value. In other words, the control device 3 can perform force control with roughly the same accuracy as the force sensor 50.

[0108] An example of a method for applying the torque sensor correction amount will be described below. The process for applying the torque sensor correction amount includes (3) a calculation process for converting the torque sensor detection value into a force acting on the control point P of the machine 2, and (4) a calculation process for applying the torque sensor correction amount to the force acting on the control point P before correction, which is calculated from the torque sensor detection value. Note that the calculation process (3) is the same as the calculation process (1) in the first embodiment, so a description thereof will be omitted.

[0109] (4) An example of calculation processing for applying the torque sensor correction amount to the force acting on control point P before correction, which is obtained from the torque sensor detection value, is described below. As expressed in the following formula, the force acting on control point P before correction, which is obtained from the torque sensor detection value (force F1 in the force acting direction in this example), is multiplied by the torque sensor correction amount (force correction amount C in this example), and the result is the force acting on control point P after correction (force F2 in the force acting direction in this example).

[0110]

number

[0111] In this way, the torque sensor correction amount is applied. Note that, although a single torque sensor correction amount is applied throughout the entire deburring operation, the present invention is not limited to this, and in other embodiments, a single torque sensor correction amount may be applied for each predetermined operation section during the deburring operation or for each predetermined time interval during the deburring operation.

[0112] In addition, in the sixth embodiment, the torque sensor is adjusted using an image of the area where deburring work has been performed, but in other embodiments, the torque sensor may be adjusted using an image of the area where polishing work has been performed.

[0113] In the above embodiment, the torque sensor is adjusted according to the work content of the machine 2 (fitting work, surface matching work, phase matching work, screw tightening work, constant force pressing work, polishing work, deburring work, etc.), and the result of the torque sensor adjustment (correction amount) is applied according to the work content of the machine 2. However, even if the work content is different, the result of the torque sensor adjustment (correction amount) can be mutually applied to work content in which the distance from the torque sensor to the control point P is approximately the same and the direction of force action is approximately the same. For example, the correction amount of the torque sensor obtained in polishing work may be applied to deburring work.

[0114] The system configuration of a mechanical system 1 according to one embodiment will be described below. Fig. 7 is a block diagram of the mechanical system 1 according to one embodiment, and Fig. 8 is a block diagram of the mechanical system 1 according to another embodiment. The mechanical system 1 shown in Fig. 7 employs a standalone system that is not connected to a network such as a WAN (wide area network) or a LAN (local area network), whereas the mechanical system 1 shown in Fig. 8 employs a client-server system that is connected to a network.

[0115] The machine system 1 shown in FIG. 7 includes one machine 2 and one control device 3 that controls the machine 2. The machine 2 includes a torque sensor 20 that detects torque acting on a link and an actuator 21 that drives the link. The control device 3 includes a control unit 32 that performs force control or mass measurement using the torque sensor 20, and a torque sensor adjustment unit 30 that adjusts the torque sensor 20 using one of external devices 5, such as a force sensor 50, a workpiece 51 with a known mass, and a visual sensor 52, or using internal data recorded in a memory unit 31. It should be noted that the torque sensor adjustment unit 30 performs all of the torque sensor adjustment functions described in the first to sixth embodiments. The torque sensor adjustment unit 30 adjusts the torque sensor 20 (calculates the correction amount) depending on the work content of the machine 2.

[0116] After adjusting the torque sensor 20, the torque sensor adjustment unit 30 records the adjustment results (correction amount) of the torque sensor 20 as internal data in the memory unit 31. Furthermore, the torque sensor adjustment unit 30 may automatically set the torque sensor adjustment to complete when the torque sensor adjustment has been performed a predetermined number of times or when the results (correction amount) of the torque sensor adjustment have converged (when the correction amount of the torque sensor for each adjustment falls below a predetermined threshold). After the torque sensor adjustment is complete, the external device 5 is removed from the machine 2. In subsequent work on another workpiece, the torque sensor adjustment unit 30 applies the correction amount of the torque sensor 20 to the force acting on the control point P calculated from the detection value of the torque sensor 20, and the control unit 32 performs force control or mass measurement based on the force acting on the corrected control point P.

[0117] As shown in the figure, the memory unit 31 of the control device 3 records, as internal data, the work content of the machine 2, the external device 5 used to adjust the torque sensor 20, the correction amount of the torque sensor 20, the coordinate system number to be used, and the direction of force action. In addition, the memory unit 31 records, as internal data, various data such as whether the adjustment of the torque sensor 20 is valid, invalid, or complete, time-series data of the torque sensor 20, time-series data or mass of the external device 5, and the target cutting amount.

[0118] The machine system 1 shown in Fig. 8 includes a plurality of machines 2, a plurality of control devices 3 that respectively control the plurality of machines 2, and a server device 60 that is connected to the plurality of control devices 3 via wired or wireless connections. The machines 2 are configured with the same specifications and include torque sensors 20 that detect torque acting on links and actuators 21 that drive the links. The control devices 3 include a control unit 32 that performs force control or mass measurement using the torque sensors 20, and a communication control unit 62 that can communicate with the server device 60 via wired or wireless connections.

[0119] The server device 60 includes a communication control unit 61 capable of communicating with the control device 3 via a wired or wireless connection, and a torque sensor adjustment unit 30 that adjusts the torque sensors 20 of each of the multiple machines 2 using an external device 5 or using internal data or external data recorded in the storage unit 31. It should be noted that the torque sensor adjustment unit 30 performs all of the torque sensor adjustment functions described in the first to sixth embodiments. The torque sensor adjustment unit 30 adjusts each of the torque sensors 20 of the multiple machines 2 in accordance with the work content of each of the multiple machines 2.

[0120] After adjusting the torque sensor 20 of the specific machine 2, the torque sensor adjustment unit 30 records the adjustment results (correction amount) of the torque sensor 20 as internal data in the storage unit 31. Furthermore, the torque sensor adjustment unit 30 may automatically set the torque sensor adjustment for the specific machine 2 to be complete when the torque sensor adjustment has been performed a predetermined number of times for the specific machine 2, or when the results of the torque sensor adjustment (correction amount) for the specific machine 2 have converged (when the torque sensor correction amount for each adjustment becomes equal to or less than a predetermined threshold). After the torque sensor adjustment for the specific machine 2 is completed, if the work content of the specific machine 2 is different from the work content of another machine 2, the external device 5 is removed from the specific machine 2 and attached to the other machine 2, and the torque sensor adjustment unit 30 adjusts the torque sensor 20 of the other machine 2 using the external device 5. If the work content of the specific machine 2 is the same as or similar to the work content of the other machine 2, the torque sensor adjustment unit 30 adjusts the torque sensor 20 of the other machine 2 using the internal data for the specific machine 2 recorded in the storage unit 31 or the external data recorded in the control device 3 of the specific machine 2.

[0121] When working on a different workpiece from the next time onwards, the torque sensor adjustment unit 30 applies the correction amount of the torque sensor 20 for each machine 2 to the force acting on the control point P calculated from the detection value of the torque sensor 20 for each machine 2, and the control unit 32 performs force control or mass measurement based on the force acting on the control point P after the correction.

[0122] As shown in the figure, the storage unit 31 of the server device 60 records, as internal data, the number of the machine 2, the work content of the machine 2, the external device 5 used to adjust the torque sensor 20, the correction amount of the torque sensor 20, the coordinate system number to be used, and the direction of action of the force. In addition, the storage unit 31 records, as internal data, various data such as whether the adjustment of the torque sensor 20 is valid, invalid, or complete, the time-series data of the torque sensor 20, the time-series data or mass of the external device 5, the target cutting amount, etc.

[0123] 7 or 8, the torque sensor adjustment unit 30 is provided in the control device 3 or the server device 60, but in yet another embodiment, the torque sensor adjustment unit 30 may be provided in the teaching device 4. It should also be noted that the teaching device 4 may also function as the server device 60 described above.

[0124] According to the above embodiment, the force acting on the control point P of the machine 2 can be measured with high accuracy using the torque sensor 20 attached to the link of the machine 2.

[0125] The storage unit 31 is configured with memories such as RAM (random access memory), ROM (read only memory), SSD (solid state drive), etc. The torque sensor adjustment unit 30, control unit 32, and communication control units 61-62 are configured with processors such as PLC (programmable logic controller), CPU (central processing unit), MPU (micro processing unit), FPGA (field programmable gate array), and ASIC (application specific integrated circuit), but in other embodiments, the torque sensor adjustment unit 30, control unit 32, and communication control units 61-62 may be configured with programs executed by a processor.

[0126] The programs executed by the aforementioned processors, drive circuits, etc. may be provided by being recorded on a computer-readable non-transitory recording medium, such as a CD-ROM, or may be distributed via wired or wireless connections from a server device on a WAN (wide area network) or LAN (local area network).

[0127] Although various embodiments have been described herein, it should be recognized that the present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims. [Explanation of symbols]

[0128] 1 Mechanical Systems 2 machines 3. Control device 4 Teaching device 5 External equipment 10 Link (Base) 11 Link (swivel body) 12 Links (Upper Arm) 13 Link (forearm) 14-16 links (wrist element) 17 Tools 20 Torque sensor 21 Actuator 30 Torque sensor adjustment section 31 Storage section 32 Control section 40 Force control setting screen 41 Work Contents 42 Sensor Types 43 Sensor adjustment mode 44 External equipment for adjustment 45~46 Coordinate system number 47 Direction of force action 50 Force Sensor 51 Workpiece with known mass 52 Visual Sensor 60 Server equipment 61~62 Communication control unit C1~C3 coordinate system J1~J6 axis P control point W1~W2 Work

Claims

1. a control unit that performs force control or mass measurement using a torque sensor that detects torque acting on a link of the machine; a torque sensor adjustment unit that adjusts the torque sensor using an external device or using internal or external data; Equipped with The external device includes one of a force sensor attached near a control point of the machine, a workpiece having a known mass, and a visual sensor.

2. a control unit that performs force control or mass measurement using a torque sensor that detects torque acting on a link of the machine; a torque sensor adjustment unit that adjusts the torque sensor using an external device or using internal or external data; Equipped with The torque sensor adjustment unit adjusts the torque sensor in accordance with the type of work being performed by the machine.

3. a control unit that performs force control or mass measurement using a torque sensor that detects torque acting on a link of the machine; a torque sensor adjustment unit that adjusts the torque sensor using an external device or using internal or external data; Equipped with The torque sensor adjustment unit adjusts the torque sensor using an image of a portion that has undergone at least one of a deburring operation and a polishing operation.

4. a control unit that performs force control or mass measurement using a torque sensor that detects torque acting on a link of the machine; a torque sensor adjustment unit that adjusts the torque sensor using an external device or using internal or external data; Equipped with The control unit applies a correction amount for the torque sensor according to the work content of the machine.

5. 5. The control device according to claim 1, wherein the torque sensor adjustment unit sets the adjustment of the torque sensor to be completed when the adjustment of the torque sensor has been performed a predetermined number of times or when a result of the adjustment of the torque sensor has converged.

6. The control device according to claim 1 , wherein the torque sensor adjustment unit applies a result of the adjustment to force control or mass measurement of another workpiece.

7. The control device according to claim 2 , wherein the external device includes any one of a force sensor attached near a control point of the machine, a workpiece having a known mass, and a visual sensor.

8. The control device according to claim 1 , wherein the torque sensor adjustment unit adjusts the torque sensor in accordance with the type of work being performed by the machine.

9. 9. The control device according to claim 2, wherein the operation content includes any one of a fitting operation, a surface matching operation, a phase matching operation, a screw fastening operation, a constant force pressing operation, a polishing operation, and a deburring operation.

10. The control device according to claim 1 , wherein the torque sensor adjustment unit adjusts the torque sensor using an image of a portion that has undergone at least one of a deburring operation and a polishing operation.

11. a control unit that performs force control or mass measurement using a torque sensor that detects torque acting on a link of the machine; a torque sensor adjustment unit that sets the adjustment of the torque sensor to be completed when the adjustment of the torque sensor has been performed a predetermined number of times or when the result of the adjustment of the torque sensor has converged; Equipped with The control unit applies a correction amount for the torque sensor according to the work content of the machine.

12. a machine equipped with a torque sensor that detects a torque acting on a link; a control unit that performs force control or mass measurement using the torque sensor; a torque sensor adjustment unit that adjusts the torque sensor using an external device or using internal or external data; Equipped with The external device includes one of a force sensor attached near a control point of the machine, a workpiece having a known mass, and a visual sensor.

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