JP2005014156A - Modularization system multi-articulated robot and its electric actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a practical system for shortening joints, and further enhancing safety, by simplifying complexity on a constitution and complexity on control as a multi-articulated robot caused by having a large number of driving members for performing different control with respective joint units. <P>SOLUTION: This multi-articulated robot adopts a combination of a rotation correcting mechanism and an offset rotary mechanism for the respective joint units; and uses the modularized same system electric actuator for the rotation correcting mechanism and the offset rotary mechanism of the respective joints; and adopts a worm gear mechanism having the reverse rotation preventing function composed of a worm and a worm wheel for a speed reduction mechanism used for the electric actuator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modular offset joint unit and a control technique for an offset joint robot using the same.
[0002]
2. Description of the Related Art The present applicant has filed an application (Patent Document 1) for a basic technique related to a robot using an offset joint unit and has been registered as Japanese Patent No. 3326472. As shown in FIG. 9, the multi-joint robot of the present invention has a multi-joint having at least a plurality of offset rotary joints in which the drive side arm 106 and the driven side arm 107 are rotationally driven around an offset rotary axis inclined with respect to the arm axis. In the robot, a joint rotation transmission mechanism 109 with a high reduction ratio is fixed to the front end of the driving side arm 106 at a predetermined offset angle γ, and the joint rotation transmission mechanism 109 is provided on the driving side stator portion and the driven side. A rotor portion, the stator portion is rotatably fixed to the stator housing 120, a cam surface is formed on the outer peripheral surface, a hollow rotary shaft that is driven to rotate by the motor 110, and an inner peripheral surface The cam operating surface that engages with the cam surface 131 of the hollow rotary shaft is fixed to be elastically deformable with the outer peripheral surface being a tooth surface. The rotor member is fixed to the rotor housing 130, is engaged with the input gear member 132 of the stator portion, and rotates with the same rotational axis as the hollow shaft. Thus, the driven arm 107 is fixed to the rotor housing 130 to constitute an offset rotary joint.
[0003]
With the above-described configuration, the offset rotary joint of the present invention has a conical rotational movement at an offset angle with the driven side link as a vertex at the intersection of the link axis and the offset rotary axis. By providing it, it is possible to perform precise three-dimensional positioning in a wide range of movement of the end effector with a simple mechanism only of rotational movement. In addition, each joint has a high reduction ratio transmission / torque increase mechanism in the joint rotation transmission mechanism in the joint, so a small drive motor can be used to transmit stronger rotational torque, and the joint can be made smaller. It can be formed lightweight. This is very advantageous for a multi-joint multi-joint robot, and it is possible to obtain an offset rotary joint with a small size and light weight and higher payload, and a highly functional multi-joint robot capable of precise positioning control. Can do.
[0004]
FIG. 11 is a block diagram showing the basic configuration of the articulated robot control method disclosed in Patent Document 1. In FIG. This robot system includes a work planning system A, a manipulator system (pointing to a driving work unit including an arm, a joint, an end effector, and a control unit that directly controls them) B, and an image recognition system C. The work planning system A includes various databases 170, work planning means 171, trajectory generation means 172, and manual control input equipment 173 such as a joystick or keyboard for remote teaching or manual operation as necessary. In the various databases 170, all information and data necessary for work planning for causing the robot to perform necessary work are determined and input. Information and data necessary for the work plan include configuration information of the articulated robot main body (for example, functional configuration of each joint, functional configuration of the end effector, etc.), installation information of the articulated robot main body (for articulated robot main body and image recognition) There are fixed position coordinates of a camera and an object, an operation range of an articulated robot, etc.) and an operation method of the articulated robot (determined information such as a manual operation mode, a program operation mode, and an automatic operation mode). Then, block area data for each block taught in advance is also stored. In addition, the object shape database in which the shapes of various work objects are databased, and various work databases in which various basic work contents such as assembly methods and processing methods are databased are stored in ROM so that objects of various shapes can be obtained. Various tasks can be performed on objects by calling them from the database.
[0005]
The manipulator system B includes a joint torque distribution unit 175 that determines the joint torque of each joint according to the hand torque command from the trajectory generation unit 172, and a joint angle that calculates the joint angle of each joint based on the hand angle and the hand position command. Calculation unit 176, joint unit means including servo motor 180 provided at each joint 179, tachometer 181 and encoder 182, etc., force / torque sensor 187 provided at end effector 186, angle sensor 188, gravity sensor 189 and the like. Each joint also includes a communication interface, a joint torque distribution unit 175 and a joint angle calculation unit 176, a CPU for executing and reporting commands, and a joint database.
[0006]
The offset rotary joint of this multi-joint robot can be constructed with only a rotary mechanism, so it can handle high loads with a relatively small arm, but has an offset angle (oblique angle) with respect to the cylinder axis. Since the bent shaft is rotated in a conical shape, the bending angle with respect to the cylindrical shaft is taken, and thus there is a drawback that the direction of the bending angle is not determined. Therefore, for example, there is a problem that it is difficult to perform a simple two-dimensional bending operation such as a finger joint. Therefore, the present applicant has previously presented an offset rotary joint unit with a rotation correction mechanism (Patent Document 2) that can perform a two-dimensional operation only by a rotation mechanism, can cope with a small size to a large size, and can support a high load load. As shown in FIG. 10, the offset rotary joint unit with the rotation correction mechanism includes a first arm, a rotation correction arm that is driven to rotate about the axis of the first arm, and an axis that obliquely intersects the rotation correction arm. The second arm that is rotationally driven constitutes a set of offset rotary joint units, and the first arm and the rotation correction arm are connected via a rotation correction joint mechanism, and the rotation correction arm and the second arm The arms are connected via an offset rotary joint mechanism. The rotation correction joint mechanism and the offset rotation joint mechanism are driven by the same drive source via the biaxial reversal mechanism, thereby facilitating control and eliminating minute operation delays. In addition, there is an advantage that the combination joint can be reduced in size. With the rotation of the offset rotation joint mechanism, the rotation correction joint mechanism rotates in the reverse direction, so that the second arm can perform a two-dimensional bending operation with respect to the first arm only by the rotation mechanism. .
[0007]
The articulated robots that have been improved in this way are widely applied to industrial robots in production lines (welding, transport, assembly, etc.) and healing robots (humanoid robots, amusement robots, animal robots, etc.). Expected. However, in the joint mechanism technology of the conventional offset-type articulated robot that has been developed for trial purposes, a motor, a gear train with a high reduction ratio, an encoder, a brake, etc. are built in the arm for each joint. It becomes a structure. For this reason, the offset rotary joint and the correction joint mechanism are structurally separated from each other and are difficult to integrate and miniaturize, and it is impossible to smoothly perform a fine two-dimensional bending operation (finger bending operation) for each joint. is there. Moreover, productivity (assembly / adjustment / repair) is also difficult, and there are large gaps with users (price, mass production, convenience of operation, etc.), and it has been difficult to get to market. In addition, the harmonic drive mechanism has been used as a high reduction ratio transmission mechanism for the drive system, but it is generally composed of a spur gear train, so when the drive power is turned off, such as when the control system fails, the arm does not hold the posture. There was a danger of causing an accident in which it started to move on its own due to its own weight and collided with people and things, and there was also a safety problem. Further, as a control system configuration, a controller is individually installed for each actuator of each joint unit, which is structurally complicated and impedes practical use in terms of cost.
[0008]
[Patent Document 1] Japanese Patent Laid-Open No. 2001-138279 “Articulated Robot and its Control Method” Published May 22, 2001 FIG.
[Patent Document 2] Japanese Patent Application Laid-Open No. 2003-25269 “Offset rotary joint unit with rotation correction mechanism” published on January 29, 2003
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to reduce the structural complexity and control complexity of an articulated robot associated with a large number of drive members that perform different control for each joint unit. The object is to provide a practical system that simplifies and shortens the joint interval so as to enable finer work, and also increases safety.
[0010]
In an articulated robot employing a combination of a rotation correction mechanism and an offset rotation mechanism for each joint unit, the present invention is modularized in the rotation correction mechanism and the offset rotation mechanism for each joint. An electric actuator of the same system is used, and a worm gear mechanism having a reverse rotation prevention function consisting of a worm and a worm wheel is adopted as a speed reduction mechanism used for the electric actuator.
[0011]
An electric actuator according to the present invention includes a small motor having a rotation amount adjusting function, a worm in which rotation of the motor is coupled through a transmission mechanism, and an encoder for detecting the rotation amount of the worm. The worm is meshed with a worm wheel rotatably supported via a bearing mechanism with respect to the fixed flange, and the worm wheel is modularized in such a manner that an output flange is integrated. ing.
[0012]
The joint unit of the present invention uses the modularized electric actuator as it is as a rotation correction mechanism, and fixes the base side of the offset rotation mechanism to the output side flange. The fixing flange of the electric actuator is fixed by inclining the γ angle, and the output side member of the offset rotation mechanism is fixed to the output side flange.
Furthermore, the joint unit of the present invention includes a slip ring that transmits electric power and signals between rotation mechanisms adjacent to the through shaft to a fixed flange of the modularized electric actuator, and a rotation angle of a worm wheel in the electric actuator. It is assumed that the angle encoder for detecting the is fixed.
In the rotation correction method in the joint unit of the present invention, the electric actuator of the rotation correction mechanism is driven and controlled so that the rotation is corrected by an amount corresponding to the rotation angle of the offset rotation mechanism detected by the encoder.
[0013]
The system for controlling an articulated robot according to the present invention includes a controller and switching means smaller than the number of actuators incorporated in the system, and controls and controls each joint unit by switching over time. In addition, the controller switching condition is set so that the priority is increased for a joint that requires a large motion, and the switching is used only for a joint that has a small motion.
[0014]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, regarding the complexity of construction as an articulated robot due to the presence of a large number of drive members that perform different control for each joint unit, basically, each joint unit is rotated. A combination of a correction mechanism and an offset rotation mechanism is used, and the same electric actuator that is modularized is used for the rotation correction mechanism and offset rotation mechanism of each joint, thereby simplifying the mechanism and reducing costs. . In addition, when the drive power is turned off, there is no posture maintenance function, and the arm starts to move freely due to its own weight, etc., and prevents accidents where it collides with people or objects. A worm gear mechanism with a reverse rotation prevention function consisting of a worm and a worm wheel is adopted as the speed reduction mechanism.
[0015]
Further, the rotation correction method in the joint unit of the present invention feeds back the rotation angle of the offset rotation mechanism detected by the encoder without using a mechanical mechanism to the control system, and performs the rotation correction as a control operation. Thus, the electric actuator of the rotation correction mechanism is driven and controlled. For the operation control of an articulated robot having a large number of drive members that perform different control for each joint unit, a set of electric actuators is provided for each joint unit, and each controller is driven by a control computer. Instead, a controller that shares the control of the electric actuators of a plurality of joint units is used in a time-series manner to reduce the number of parts and provide an energy saving and low cost system.
[0016]
[Embodiment 1] The configuration of an embodiment of a modular electric actuator according to the present invention will be described below with reference to FIG. In the figure, A is a side view and B is a front view. 1 is an electric actuator, 2 is a small motor capable of controlling the amount of rotation such as a servo motor, a stepping motor or a pulse motor, 3 is a gear train, 4 is an output gear of the gear train and a manual rotary shaft 5 integrated with a worm shaft. Belt for transmitting rotation, 6 is a worm, 7 is an encoder for monitoring the rotation speed of the worm 6, 8 is a worm wheel meshing with the worm 6, 9 is a fixed flange, 10 is an output flange, and 11 is an adjacent rotation. A slip ring 12 transmits a signal between the moving mechanisms. An encoder 12 detects an angle of the output side flange 10 with respect to the fixed side flange 9. The rotating shafts of the motor 2 and the worm 6 are arranged in a compact and parallel manner in the casing. A casing containing the motor 2 and the worm 6 is fixed to a fixed system of the fixed flange 9, and a worm wheel 8 is rotatably supported on the fixed system via a bearing. The worm wheel 8 is formed with an output side flange 10 as an integral structure on the opposite side of the fixed side flange 9. A slip ring 11 and an angle encoder 12 are fixed to the worm wheel 8 in the through hole of the fixed flange 9. Further, a hexagonal hole is formed at the end of the manual rotation shaft 5 so that when the driving of the electric actuator 1 is stopped due to a failure or the like, the hexagonal handle can be fitted and driven manually. It is.
[0017]
In the electric actuator 1 configured as described above, when the motor 2 is driven to rotate, the worm 6 is rotated via the gear train 3 and the belt 4. The state of rotation (rotational speed) can be monitored by the encoder 7 in a pilot display. The rotation of the worm causes the worm wheel 8 in meshing relation to rotate, and the rotation ratio of the gear is set to about 1/10 to 1/30. Due to this worm gear relationship, the rotation of the worm 6 transmits the rotation to the worm wheel 8, but the rotation of the worm wheel 8 does not transmit the rotation to the worm 6, thereby forming a so-called one-way transmission mechanism. This is one of the features of the electric actuator of the present invention. The rotation of the worm wheel 8 rotates the output side flange 10, the slip ring 11 and the angle encoder 12, and the angle encoder 12 detects the angle difference between the fixed side flange 9 and the output side flange 10.
The modular electric actuator as described above has a casing for housing members from the motor 2 to the worm 6 and the encoder 7 as shown in FIG. 2 with respect to the rotating mechanism portion having the fixed side flange 9 and the output side flange 10. As shown, it is possible to attach not only in the state B in which the motor unit is erected, but also in the state C in which the motor part is laid on the fixed side A or the output side. When incorporated in an actual joint, an installation form that fits in a compact manner can be employed.
[0018]
[Embodiment 2] Next, the construction of an embodiment of the modular electric actuator according to the present invention will be described with reference to FIG. In the figure, A is a side view in which the lower half is a sectional view, B is a sectional view taken along the line aa in FIG. A, and C is a sectional view taken along the line bb in FIG. 1 'is an electric actuator, 2 is a small motor that can control the amount of rotation, 3 is a gear train, 4 is a belt that rotates and transmits an output gear of the gear train and a manual rotation shaft 5 integrated with a worm shaft, and 5a is a manual A transmission gear integrally attached to the rotary shaft 5, 6 a and 6 b are two worms rotated by the transmission gear 5 a via transmission gears 6 c and 6 d fixed coaxially, and 7 is a rotational speed of the transmission gear 5 a. The encoders 8a and 8b for monitoring the worm are worm gears that mesh with the worms 6a and 6b, respectively, and are formed in two rows on the circumferential surface of the worm wheel 8. Reference numeral 9 denotes a fixed side flange, 10 denotes an output side flange, 11 denotes a slip ring that transmits a signal between adjacent rotating mechanisms, and 12 denotes an encoder that detects an angle of the output side flange 10 with respect to the fixed side flange 9. The difference from the previous embodiment is that the rotating shaft of the motor 2 and the transmission gear 5a and two worms 6a and 6b are arranged in a compact and parallel manner in the casing, and meshes with the two worms 6a and 6b. This is a point formed on the circumferential surface of the worm wheel 8 in two rows. In this example, the worms 6a and 6b have the same pitch but the tooth profile has a reverse inclination angle, and the worm gears 8a and 8b meshing therewith have the same relationship. A casing containing a rotating shaft of the motor 2 and the transmission gear 5a and two worms 6a and 6b is fixed to the fixed flange 9, and a worm wheel 8 is rotatably supported via a bearing with respect to this fixed system. Yes. The worm wheel 8 is formed with an output side flange 10 as an integral structure on the opposite side of the fixed side flange 9. The point that the slip ring 11 and the angle encoder 12 are fixed to the worm wheel 8 in the through hole of the fixed side flange 9 and the point that the manual handle is attached to the manual rotating shaft 5 are the previous examples. And there is no difference.
[0019]
When the motor 2 is driven to rotate, the electric actuator 1 ′ having the above-described configuration causes the worms 6a and 6b to rotate in the same direction via the gear train 3, the belt 4, and the transmission gear 5a. The state of this rotation can be monitored in a pilot display by an encoder 7 attached to the rotation shaft of the transmission gear 5a. The rotation of the worms 6a and 6b gives a rotational force to the meshing worm gears 8a and 8b, but both rotate the worm wheel 8 in the same direction. The rotation ratio of this gear is also about 1/10 to 1/30. The rotation of the worms 6a and 6b transmits the rotation to the worm wheel 8 due to this worm gear relationship, but as a so-called one-way transmission mechanism, the rotation of the worm wheel 8 does not transmit the rotation to the worm 6, and the meshing tooth shapes are different. Therefore, a pair of worm gears are engaged during reverse rotation, thus providing a strong reverse rotation prevention function. This is one of the characteristic points of the electric actuator 1 ′ of this embodiment. The rotation of the worm wheel 8 rotates the output side flange 10, the slip ring 11 and the angle encoder 12, and the angle encoder 12 detects the angle difference between the fixed side flange 9 and the output side flange 10. Similar to the example. The modularized electric actuator 1 ′ described above also has a casing for housing members from the motor 2 to the worms 6 a and 6 b and the encoder 7 with respect to the rotating mechanism unit having the fixed side flange 9 and the output side flange 10. It is possible to attach it to the fixed side or the output side. In addition to the difference that the worm gear mechanism is constituted by a set of inverted teeth, there is no significant difference in driving operation from the previous embodiment.
[0020]
An embodiment in which the modular electric actuator 1 (or 1 ′) as described above is incorporated in a joint unit of an offset joint robot will be described. As shown in FIGS. 4 and 5, the joint unit 20 of the present invention includes a rotation correction joint mechanism 21 connected to the base cylinder on the base side and a tip-side offset rotary joint mechanism 22. The same modularized electric actuator 1 described above is incorporated in each of the two rotation mechanisms. In the offset rotary joint mechanism 22, a base side member 22a and a distal end side member 22b integral with the sub-cylinder are rotatably supported with an offset angle γ. That is, in the rotation correction joint mechanism portion 21, one electric actuator A is used as it is as the rotation correction joint mechanism portion 21 on the base side, and the fixed side flange 9 is the output end of the offset rotation joint of the base portion or the adjacent base side joint unit. The output side flange 10 is fixed to the base side member 22a of its own offset rotary joint. In the offset rotary joint mechanism portion 22, a through hole is formed in the base side member 22a, and one electric actuator B is loaded in the hollow portion, and the fixed side flange 9 is attached to the base side member 22a of the offset rotary joint. The output side flange 11 is fixed to the rotation surface of the tip end side member 22b of the offset rotation joint 22 of itself. One of the merits of the present invention is that the electric actuator 1 (or 1 ′) that is modularized in the electric actuator A and the electric actuator B can be adopted.
[0021]
The state shown in FIG. 4 is a so-called variable angle 0 in which the base-side fixed end of the base-side rotation correction joint mechanism 21 and the tip-side output end of the tip-side offset rotary joint mechanism 22 in the joint unit 20 are in a straight line. It is the time. When attempting to bend the joint by α angle from this state, first, the electric actuator 1 in the offset rotary joint mechanism portion 22 is rotationally driven to obtain an angle α formed by the shafts of the base side member 22a and the distal end side member 22b. Thus, the electric actuator is driven to rotate by β angle. However, since the relationship between α and β depends on the offset angle γ, if the offset angle γ is determined, α and β are in a uniquely corresponding relationship. By this driving, the base side fixed end and the distal end side output end of the joint unit 20 are in the state of the variable angle α, but the angle is not the angle on the paper surface of FIG. . Therefore, in order to make this variable angle α an angle on the paper surface of FIG. 4, in the present invention, the rotation correction joint mechanism portion 21 on the base side of the joint unit 22 drives the −β angle to correct the β angle. To correct the rotation. By operating both the base side fixed end of the rotation correction joint mechanism 21 on the base side and the tip side offset rotation joint mechanism 22, the angle change control in the two-dimensional plane can be performed in the joint unit 20. The state shown in FIG. 5 shows the result of bending in the two-dimensional space with a maximum variable angle 2γ, that is, 60 ° in this case, in the joint unit 20 having an offset angle γ of 30 degrees. In the example shown here, both the electric actuator A and the electric actuator B are incorporated in a form in which the casing of the motor portion is tilted to the fixed side in order to reduce the size of the excess protrusion and reduce the size.
[0022]
The configuration and operation of the articulated robot of the present invention will be described with reference to FIG. The example shown here is an articulated robot in which five joint units are connected to the base and an end effector E is attached to the tip. The number of joints is not limited to 5, and may be a general number N. Each arm from the base RB to the tip is gradually narrowed, but each joint unit has the same modularization as the electric actuator A for the rotation correcting joint and the electric actuator B for the offset rotating joint. A built-in electric actuator is incorporated. The sizes of the electric actuators are not all the same. In general, the electric actuator is large on the base side and small on the end effect side. In this multi-joint robot system, the rotation controller CR of the base RB and the controller CE of the end effector E as control units, the electric actuators A1 to A5 of the five joint units, and the controllers CA1 to CA5 and CB1 to CB5 of the electric actuators B1 to B5 And a control signal for each controller is transmitted from the control computer CC and input via an interface. The basic movement of the robot is patterned, and information on the control signal output to the controller for driving each electric actuator is stored as a look-up table in the storage device corresponding to each pattern. If it is a routine operation, the stored information corresponding to the basic pattern can be used as it is. However, for the original operation, the computer reads out the similar pattern information and calculates a correction amount for each actuator and outputs a control signal. . Further, the drive of each of the electric actuators A1 to A5 and B1 to B5 is monitored by the encoder 7 and output as signals MA1 to MA5 and MB1 to MB5, and the rotation correcting joint mechanism 21 of each driven joint unit 20 is output. Then, the angle information of the tip-side offset rotary joint mechanism unit 22 is output from each angle encoder 12 and sent back to the corresponding controllers CA1 to CA5 and CB1 to CB5 as angle detection signals EA1 to EA5 and EB1 to EB5.
[0023]
The operation and control signals of the articulated robot shown in FIG. 7 will be described in detail with reference to FIG. First, a signal D0 for turning on the power of the controllers of the joint units 20, the base RB, and the end effector E is output from the control computer CC, and the actuators are turned on. Subsequently, drive control signals MCA1 to MCA5 and MCB1 to MCB5 to the actuators A and B corresponding to the operation of the robot designated in the control computer CC are calculated in the control computer CC, and the controllers A1 to A5 of the actuators A and B are calculated. And B1 to B5. The drive control signals MCB1 to MCB5 are for setting the angle of the offset joint to a designated α °, and drive control the actuator B of each joint unit in that way. As a result of the operation, the joint is rotated by an angle β. Therefore, it is necessary to drive the actuator A of the rotation correcting mechanism portion 21 in order to twist back the angle β. Therefore, in the present invention, the detection signals EB1 to EB5 of the angle encoder 12 of the actuator B, which is the angle information displaced by driving the offset rotary joint mechanism unit 22, is fed back to the control computer CC, and the actuator A of the rotation correction mechanism unit 21 is driven. The rotation is corrected by controlling. The drive control signals MCA1 to MCA5 to the actuator A of the rotation correction mechanism 21 are output from the control computer CC to each actuator A with the rotation correction signal superimposed on the original rotation drive control signal of each joint. As a result, the joint is driven and controlled in three dimensions as much as possible in a designated bending angle state in a designated direction.
[0024]
The articulated robot of the present invention and its control method described with reference to FIG. 6 includes a controller that has a one-to-one correspondence with a large number of modular electric actuators installed in the system of the articulated robot. Since the system can be driven simultaneously and in parallel, the system is fast in response. However, since the controller is required for the number of electric actuators, there is a demerit that is expensive in terms of cost. Therefore, in the modified example of the present invention, M (M is N) including a controller of actuator A and actuator B for N (N = 5 in the figure) sets of joint units including actuator A and actuator B as shown in FIG. The present invention presents a control method in which only one (smaller integer) number of controllers are provided, and one controller controls a plurality of joint units using switching in time series. In the illustrated example, a switch group for selectively connecting the actuators A and B of each joint unit is selectively connected to the controller by a scanning operation. Those that are currently connected to the controller are indicated by solid lines, and those that are not connected are indicated by dashed lines. By adopting this method, there is a demerit that it takes extra time to operate, but in order to reduce the demerit by reducing the number of controllers, higher priority is given to joints that require large movement, and small movement If the use conditions of the controller are set so that only the joints are switched, it is possible to perform drive control of the robot by this method without causing a large delay in the control time. Large operations require a lot of operating time, and small operations have a short operating time. In the case of a robot that does not require a control speed, a system that ultimately includes only one controller and sequentially switches and controls each joint unit may be provided.
[0025]
The joint unit of the present invention is not limited to the articulated robot as described above, but can be used as a single unit for driving a stage on which a device such as a display or a lighting fixture is mounted. If the control angle is small, the angle may be detected by integrating the detection speed of the speed monitor encoder 7. In this case, the installation of the angle encoder 12 may be omitted.
[0026]
The modular articulated robot of the present invention employs a combination of a rotation correction mechanism and an offset rotation mechanism for each joint unit, and the rotation correction mechanism and the offset rotation mechanism for each joint are modules. The same type of electric actuator is used, and the worm gear mechanism with a reverse rotation prevention function consisting of a worm and a worm wheel is adopted as the speed reduction mechanism used for the electric actuator. In addition to simplifying the configuration complexity and control complexity of an articulated robot due to the presence of a large number of drive members, and when the drive power is turned off, such as when the control system fails However, it has a posture holding function, and the arm starts to move freely due to its own weight, etc. Divided by it is possible to improve the safety.
[0027]
In addition, the modular electric actuator of the present invention includes a small motor having a rotation amount adjusting function, a worm in which the rotation of the motor is coupled through a transmission mechanism, and an encoder for detecting the rotation amount of the worm. And the worm is meshed with a worm wheel rotatably supported via a bearing mechanism with respect to the fixed flange, and an output side flange is integrated with the worm wheel. Therefore, the structure is compact, and the distance between the fixed end and the output end can be shortened to cope with fine work.
[0028]
The joint unit of the present invention uses the modularized electric actuator according to claim 2 as the rotation correction mechanism as it is, and fixes the base side of the offset rotation mechanism to the output side flange, and also to the base of the offset rotation mechanism. The fixing flange of the modularized electric actuator according to claim 2 is fixed by inclining the γ angle, and the output side member of the offset rotation mechanism is fixed to the output side flange, so that the configuration is simplified. In addition, it is equipped with a posture maintenance function when the drive power is turned off, such as when the control system fails, improving safety.
Furthermore, a slip ring that transmits power and signals between the rotating mechanisms adjacent to the through hole to the fixed flange of the modularized electric actuator, and an angle encoder that detects the rotation angle of the worm wheel in the electric actuator. Since the joint unit of the present invention in the fixed form effectively uses the through-hole, the structure can be simplified and compact, and is particularly suitable for articulated robots that are connected in series.
[0029]
The rotation correction method in the joint unit according to the present invention drives and controls the electric actuator of the rotation correction mechanism so as to correct the rotation according to the rotation angle of the offset rotation mechanism detected by the encoder. There is no need to provide a mechanical mechanism for correcting rotation such as a two-axis reversing mechanism, and it can be easily executed by superimposing it on the original rotation control operation on the control signal.
[0030]
The articulated robot of the present invention is constructed by connecting a plurality of joint units according to claim 4 to the base portion and attaching an end effector to the tip portion, thereby simplifying the configuration. Even when the drive power is turned off, such as when a control system fails, the robot is equipped with a posture maintenance function, which can provide a highly safe robot. Further, since the angle encoder and signal transmission are performed by effectively using the through hole, the joint unit can be simplified and made compact as an articulated robot in which the joint units are connected and installed.
[0031]
A system for controlling an articulated robot according to the present invention includes a control computer having a look-up table storing information on basic motions and means for calculating a control signal for a designated motion, and a controller for controlling driving of each joint unit Therefore, the drive control of the articulated robot can be easily performed with a short calculation processing time.
In addition, the present invention controls a multi-joint robot of the present invention that includes a controller and switching means less than the number of actuators incorporated in the system, and adopts a configuration in which each joint unit is driven and controlled by switching in time series. The system can control the robot with a small number of components, and therefore can provide a system that is advantageous in terms of simplification and cost.
In addition, controller switching that is less than the number of built-in actuators in this system has a higher priority for joints that require large movements, and the controller usage conditions are such that switching is performed only for joints with small movements. The method of using the system for controlling an articulated robot according to the present invention in which the above is set can execute a part of the control sequentially in time series while minimizing the time delay.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a modularized electric actuator according to the present invention.
FIG. 2 is a diagram showing a variation of a motor fixing form in the modularized electric actuator of the present invention.
FIG. 3 is a diagram showing different embodiments of the modularized electric actuator of the present invention.
FIG. 4 is a view of the joint unit of the present invention showing an aspect when the angle of change is zero.
FIG. 5 is a view of the joint unit of the present invention showing a mode at the time of maximum deflection.
FIG. 6 is a diagram illustrating an articulated robot control operation according to the present invention.
FIG. 7 is a diagram for explaining the structure of the articulated robot of the present invention and its basic system.
FIG. 8 is a diagram for explaining the structure and rationalized system of the articulated robot of the present invention.
FIG. 9 is a diagram showing a conventional structure of an articulation unit for an offset multi-joint robot as a basis of the present invention.
FIG. 10 is a diagram showing a conventional structure of a joint unit for an offset multi-joint robot provided with a rotation correction mechanism.
FIG. 11 is a diagram for explaining a control technique of an offset multi-joint robot as a basis of the present invention.
[Explanation of symbols]
1,1 'modular actuator
2 Motor 11 Slip ring
3 Gear train 12 Angle encoder
4 belt 20 joint unit
5 Manual rotation shaft 21 Rotation correction mechanism
6, 6a, 6b Warm 22 Offset joint mechanism
7 Rotational speed encoder 22a Base side member
8 Worm wheel 22b Tip side member
8a, 8b Worm gear CC control computer
9 Fixed side flange RB Base
10 Output side flange E End effector

Claims (9)

In an articulated robot that employs a combination of a rotation correction mechanism and an offset rotation mechanism for each joint unit, a modularized electric actuator is used for the rotation correction mechanism and the offset rotation mechanism for each joint. A modular articulated robot that employs a worm gear mechanism with a reverse rotation prevention function consisting of a worm and a worm wheel. A small motor having a rotation amount adjusting function, a worm in which the rotation of the motor is coupled through a transmission mechanism, and an encoder for detecting the rotation amount of the worm are placed in a casing and externally attached. An electric actuator that is meshed with a worm wheel that is rotatably supported via a bearing mechanism with respect to a fixed-side flange, and is modularized in such a manner that an output-side flange is integrated with the worm wheel. The modular electric actuator according to claim 2 is used as it is as a rotation correction mechanism, the base side of the offset rotation mechanism is fixed to the output side flange, and the module according to claim 2 is also installed at the base of the offset rotation mechanism. An articulated unit in which the fixed flange of the electric actuator is fixed by inclining the γ angle, and the output side member of the offset rotation mechanism is fixed to the output side flange. The fixed ring flange of the modularized electric actuator is fixed with a slip ring that transmits electric power and signals between the rotating mechanisms adjacent to the through hole, and an angle encoder that detects the rotation angle of the worm wheel in the electric actuator. The joint unit according to claim 3 which is made into a form. A rotation correction method in a joint unit, wherein the electric actuator of the rotation correction mechanism is driven and controlled so that the rotation is corrected by an amount corresponding to the rotation angle of the offset rotation mechanism detected by the encoder. A multi-joint robot in which a plurality of joint units according to claim 4 are connected and attached to the base, and an end effector is attached to the tip. The multi-joint according to claim 6, further comprising: a control computer having a look-up table storing information about basic motions, means for calculating a control signal for a designated motion, and a controller for controlling driving of each joint unit. A system that controls a robot. 8. The articulated robot according to claim 7, further comprising a controller and switching means smaller than the number of actuators incorporated in the system, wherein each joint unit is driven and controlled by switching in time series. Control system. Controller switching that is less than the number of built-in actuators in this system has a higher priority for joints that require large motion, and the controller usage conditions are set so that switching is performed only for joints with small motion. The method of using the system for controlling an articulated robot according to claim 8, wherein the system is set.

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