JPH025557B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heavy object handling system control device using a light load robot.

The need for automation of multi-product production processes is increasing year by year, and automation using robots with flexibility is being carried out in order to deal with various types of work, work changes, etc.

However, automation using robots in the processing or assembly process of heavy parts requires a robot with a transport capacity commensurate with the heavy parts, and therefore has the drawback that the labor-saving effect is small compared to the price of robots. Due to this, automation was delayed.

On the other hand, as a prior art, Japanese Patent Application Laid-Open No. 54-6271 was known. In this prior art, vertical movement is performed by the drive of the balancer itself, and horizontal movement is performed by a sub-robot. Also,
Balancers are designed to be able to lift and lower heavy objects, and are not required to have high positioning accuracy in the vertical direction. Therefore, there has been a problem in that it is difficult to apply the above-described conventional technology to assembly work or processing work that requires highly accurate positioning in the vertical direction as well.

An object of the present invention is to solve the problems of the prior art described above by combining a light load robot capable of highly accurate positioning in the horizontal and vertical directions and a balancer capable of handling heavy parts through a sensor. The balancer is controlled horizontally and vertically to follow the movement of the loading robot, making it possible to handle heavy objects and perform assembly and processing operations that require highly accurate positioning. The present invention provides a heavy parts handling system control device.

By the way, the carrying capacity of a robot is determined by the load that the robot can lift. Afterwards,
By using a method in which heavy parts are suspended by a balancer and the balancer is operated by a robot, it is possible for a robot that has a payload capacity less than the weight of the heavy part to handle a heavy part that exceeds the weight capacity. . Generally, the balancer can be mechanically moved freely in the direction of the applied force in the horizontal plane, and the actuator is operated in the vertical direction by applying a predetermined signal to the balancer's control device. Therefore, the tip of the robot and the balancer are connected, and in the horizontal plane, the force generated by the robot moves the tip of the balancer, while in the vertical direction,
The robot moves in the vertical direction, and the control device of the balancer gives operation commands to the control device of the balancer to move the actuator of the balancer, thereby controlling the position and handling of the heavy parts suspended from the balancer. can be done. When moving in the vertical direction, both the robot and the balancer move their actuators, so the difference in response characteristics between the two actuators is compensated for, and the difference in position between the tips of the robot and the balancer causes the tip of the robot and the balancer to move. Control is required to keep the force generated at the joint at the tip within tolerance. Such control can be carried out by detecting the difference in position between the robot tip and the balancer tip using some kind of sensor, and by constantly adjusting the amount of operation applied to the balancer control device so that this difference becomes smaller. That is, the present invention has at least three drive sources and at least three encoders,
A positioning robot that is controlled so that the position detected by the encoder matches the target position, and has at least three degrees of freedom in which the tip of the arm can move in a horizontal plane and a vertical plane by the power of the drive source;
A balancer capable of transporting a heavy object, the tip of which is equipped with a chuck for gripping parts, is movable in the vertical direction by the power of a drive source and is movable in the horizontal direction; and the robot and the balancer. A sensor is provided at the connection part with the robot and detects a deviation in the vertical direction between the tip of the robot and the tip of the balancer, and a sensor is provided at the connection part of the robot to detect the deviation in the vertical direction between the tip of the robot and the tip of the balancer. The drive source for the robot is driven and controlled to horizontally position the chuck at the tip of the balancer connected to the tip of the robot, and the tip of the robot is moved vertically to the target point based on the command signal. A speed command value for the balancer is calculated from a vertical movement speed command value given by the robot control means and a deviation detected by the sensor by driving and controlling the drive source for the robot. A control device for a heavy object handling system, comprising: a control device for driving and controlling a driving source of the balancer based on the robot, moving the balancer to follow the robot, and positioning the chuck in the vertical direction. be.

Hereinafter, the present invention will be specifically explained based on embodiments shown in the drawings. FIG. 1 shows a heavy parts handling system to which the present invention is applied. That is, this system includes a hand 2 that grips a heavy component, and a balancer 3 that suspends the hand 2 and the heavy component.
, a small articulated robot 1 that operates this balancer, a chuck 6 located at the tip of this small articulated robot 1 and grips the tip of the balancer 3, and a chuck 6 located between this chuck 6 and the small articulated robot 1. A sensor 5 detects the vertical position difference between the tip of the small articulated robot 1 and the tip of the balancer 3.
and a control device 7 that controls the small articulated robot 1 and the balancer 3.

First, the small articulated robot 1 will be explained based on FIGS. 2 to 5. This small articulated robot 1 is a variable sequence robot that has five degrees of freedom and operates according to a preset order. 21 is a base attached to the base 20. Reference numeral 22 denotes a swivel table which is supported by the base 21 so as to be freely rotatable around a vertical axis, and is driven to rotate via a reduction gear by a drive motor 23 provided on the base 21, and constitutes one degree of freedom of the articulated robot. are doing.
A first upper arm 24 is rotatably supported on the upper part 22a of the swivel base 22 about an axis O, and is connected to the output shaft of a drive motor 25 via a speed reducer.
26 is a second upper arm arranged parallel to the first upper arm 24. 27 is the upper part 2 of the swivel base 22
A crank lever 2a is rotatably supported around an axis O, and is connected to the output shaft of a drive motor 28 via a speed reducer. A forearm 29 is rotatably connected to the swinging ends 24a and 26a of the first upper arm 24 and the second upper arm 26 so as to be parallel to the crank lever 27. Therefore, the drive motor 25
The axis O of the first upper arm 24 rotationally driven by
Rotation about the center is one degree of freedom of the articulated robot, and tilting of the forearm 29, which is rotationally driven by the drive motor 28, is also one degree of freedom of the articulated robot.

Next, a mechanism for driving the wrist 30 will be explained. Members 32a and 32 are rotatably supported at the swinging end of the crank lever 27 at the connection point where the crank lever 27 and the second upper arm 26 are rotatably connected by wrist drive motors 31a and 31b, respectively.
It is fixed at b. 33 has one end rotatably connected to point A of the swivel base 22, and the other end connected to the members 32a, 3
This is a link rotatably connected to the swinging end B of 2b. These crank levers 27 and links 33 are arranged in parallel, and the members 32a and 32a of the swivel base 22,
32b are arranged in parallel to form a parallel link mechanism. 34a and 34b are wrist drive motors 3, respectively.
A sprocket wheel is connected to 1a and 31b via a speed reducer, and is rotatably supported by the swinging end of the crank lever 27. Sprocket wheels 35a and 35b are rotatably supported by rotatably connected portions of the second upper arm 26 and forearm 29, respectively. 36a and 36b are each forearm 29
The sprocket wheel is rotatably supported at a portion rotatably connected to the wrist 30 and the wrist 30.
37a and 37b are sprocket wheels 34, respectively.
a, 34b and sprocket wheels 35a, 35
38a and 38b are flexible links such as chains that connect sprocket wheels 35a and 35b and sprocket wheels 36a and 36b, respectively, with a parallel link mechanism. . These are provided in two series, indicated by the suffixes a and b, in order to swing the wrist 30 in the direction of the arrow shown in FIG. 4 and to rotate the wrist 30 around the axis. However, each rotation of the output shaft of the wrist drive motors 31a, 31b becomes the rotation of the sprocket wheels 34a, 34b via a reduction gear, thereby driving the links 37a, 37b. Link 37a, 3
The movement of 7b is caused by sprocket wheels 35a, 35.
b, the links 38a and 38b are driven, and the wrist 30 is swung vertically (in the direction of the arrow) or rotated about the axis. On the other hand, the fixed side member 32 of the wrist drive motors 31a and 31b
a and 32b are rotatably mounted around the swinging end C of the crank lever 27 via bearings, and the swinging end B of these members 32a and 32b swings to the upper part A of the swivel base 22 via a link 33. It can be installed freely. Here, point O, point A, point B on the swivel base 22,
Point C is in a parallelogram relationship, ,,
A four-bar parallelogram link mechanism is constructed with BC and as stationary nodes. Also, the sprocket wheels 34a, 34b, 35a, 35b and the link 37
a and 37b each constitute a four-bar parallel link mechanism,
Sprocket wheels 35a, 35b, 36a,
36b and links 38a and 38b each constitute a four-bar parallel link mechanism. With this configuration, the second upper arm 26 can be moved to change the inclination of the forearm 29, and the wrist drive motor 31a,
Even if the position of the sprocket wheels 31b moves, unless the wrist drive motors 31a, 31b are driven, the sprocket wheels 34a, 34b, 3
The rotational positions of 5a, 35b, 36a, and 36b are kept constant, and the posture of the wrist 30 is kept constant. That is, the posture of the wrist 30 is kept constant regardless of the postures of the first upper arm 24 and forearm 29 without any special control.

The wrist 30 includes a cylinder 40 that is integral with the sprocket wheel 36b and rotatably supported by a bearing 39, and a cylinder 40 that is rotatably supported by a bearing 41 in the axial direction of the cylinder 40 and is attached to the rear of the sprocket wheel 36a. It is constituted by a bevel gear 42 fixed to an end and a member 44 to which a bevel gear 43 that meshes with is fixed. Therefore, if only the wrist drive motor 31a is rotationally driven, the wrist 3
0 is twisted around the axis and only the wrist drive motor 31b is rotationally driven, the cylinder 40 rotates by that much and the wrist 30 is bent.

On the other hand, the balancer 3 is specifically constructed as shown in FIG. That is, 51 is an arm with the hand holder 4 attached to its lower end. Reference numeral 52 designates an upper arm, one end of which is rotatably connected to the upper end of the arm 51, and the other end of which is rotatably supported by a movable piece 55 that is vertically slidably supported along a guide groove 54 formed on the frame 53. They are freely connected. 56 is a lower arm, one end of which is rotatably connected to the vicinity of the upper end of the arm 51, and the other end of which is connected to a roller 58 that is supported so as to be slidable left and right along a guide groove 57 formed on the frame 53. They are rotatably connected. The upper arm 52 and the lower arm 56 are formed parallel to each other. 59 is an arm;
The upper end is rotatably connected to the upper arm 52, and the lower end is rotatably connected to the roller 58. Arm 51 and arm 59 are formed parallel to each other. A rack 60 is formed at the right end of the moving piece 55, and a pinion 61 that meshes with the rack 60 is provided, and the pinion 61 is connected to a drive motor 64 via gears 62 and 63. A link 65 fixes the hand holder 4 and is rotatably supported at the lower end of the arm 51 so as to keep the posture of the hand holder 4 constant.
A parallel link mechanism 66 is connected between the moving piece 55 and the moving piece 55.
It is connected with. Further, a spring 69 is provided so that the roller 58 is located at a neutral point. Further, the frame 53 is rotatably supported at the upper end of a support column 67. Further, a rotary variable resistor 70 is attached to the hand holder 4, and an input shaft 7 for rotating the rotary variable resistor 70 is attached to the hand holder 4.
1 is provided.

Therefore, by moving the hand holder 4 in the horizontal direction, the balancer 3 can move freely while holding a heavy component in the hand 2, and can also move the input shaft 71 of the rotary variable resistor 70. For example, if it is rotated clockwise, an output corresponding to the direction and amount of rotation is input to the drive control device 72, and the drive motor 64 is rotationally driven to lower the movable piece 55 and raise the hand holder 4. Conversely, when the input shaft 71 is rotated counterclockwise, an output corresponding to the direction and amount of rotation is input to the drive control device 72, and the drive motor 64 is rotationally driven to lower the hand holder 4. Can be done. In this way, the balancer 3 can freely move in the horizontal direction, and in the vertical direction, the heavy component can be moved up and down by commands from the input shaft 71 of the rotary variable resistor 70.

Therefore, as a method for automating the vertical operation of the balancer 3, there are two methods: rotating the input shaft 71 of the balancer 3 by twisting the wrist 30 of the small articulated robot 1, and rotating the rotary variable resistor 70. There is a method of operating the balancer by directly inputting a speed command value equivalent to the speed command value generated when the balancer 3 is turned into the drive control device 72 of the balancer 3. The former method requires a total of 4 degrees of freedom for the small articulated robot 1, including 3 degrees of freedom for the position of the wrist 30 and 1 degree of freedom for twisting, while the latter method requires 4 degrees of freedom for the position of the wrist 30. Only three degrees of freedom are required as a minimum.

Next, the principle of the sensor 5 for detecting the relative positional deviation in the vertical direction between the small articulated robot 1 and the balancer 3 will be described with reference to FIG. First wrist 3
A beam 80 whose both ends are fixed to the member 44 of No. 0 and the input shaft 71 of the balancer 3 is assumed. This beam 80 is deflected due to the difference △Z between the height Z _R of the fixed end on the member 44 side from the reference plane 81 and the height Z _B of the fixed end on the input shaft 71 side from the reference plane 81. occurs. If the length of the beam 80 is l, the modulus of longitudinal elasticity is E, and the plate thickness is h, the stress σ generated on the surface of point D, which is l ₁ away from the fixed end of the beam 80, is as shown in equation (1). To, △Z
There is a proportional relationship between

σ=3E(2l ₁ -l)h/l ³ △Z...(1) Therefore, by attaching a strain gauge to point D and measuring the strain caused by this stress σ, we can construct the small articulated robot 1. The relative positional deviation between the balancer 3 and the balancer 3 in the vertical direction can be detected. In addition, the sensor 5 can be attached by fixing it to the wrist member 44 of the small articulated robot 1, or by fixing it to the input shaft 7 of the balancer 3.
There is a method of fixing it to 1. On the other hand, it differs depending on the method of mounting the sensor 5 and the method of operating the balancer 3 described above. Depending on the two mounting methods and the two operating methods, there are the following four cases.

1. The sensor 5 is fixed to the wrist member 44, and the wrist 30
When operating balancer 3 by twisting motion.

2. When the sensor 5 is fixed to the wrist member 44 and the speed command value is input directly to the drive control device 72 to operate the balancer 3.

3. When the sensor 5 is fixed to the input shaft 71 and the balancer 3 is operated by twisting the wrist 30.

4. When the sensor 5 is fixed to the input shaft 71 and the speed command value is directly input to the drive control device 72 to operate the balancer 3.

First, in the first case, since the sensor 5 is also rotated by the twisting motion of the wrist 30, the sensor 5 must have a structure that can compensate for the influence of this rotation, making the structure complicated. In the second case,
Since the wrist 30 is not moved, and since the third and fourth cases are not affected by the rotation of the wrist 30, it is possible to correct the effect of the rotation of the wrist 30 as in the first case. No particular structure is required, and the above-mentioned principle can be used as is. An example of the second case is shown in FIG.
Examples of the fourth case are shown in FIG. 9, respectively.

First, explanation will be given based on FIG. The sensor 5 is
It is composed of a beam 80 and strain gauges 82a and 82b. Here, it is better to attach one strain gauge to the upper and lower sides of the beam 80 in consideration of temperature compensation and the like.
Also, one end of the beam 80 is fixed to the member 44 of the small articulated robot 1, and the other end is fixed to the chuck 6. The chuck 6 is the input shaft 71 of the balancer 3.
The small articulated robot 1 and the balancer 3 are connected by grasping the connecting member 83 fixed to the robot. It is possible to directly connect one end of the beam 80 to the balancer 3 without going through the chuck 6, but considering safety and making use of the independent movement function of the small articulated robot 1, it is possible to connect the end of the beam 80 directly to the balancer 3 without going through the chuck 6. It is desirable to connect it to the balancer 3 through the. Further, the connecting member 83 is directly connected to the
It can also be fixed to the hand holder 4.

Next, in FIG. 9, the sensor 5 is connected to the beam 80.
a, 80b and strain gauges 82a, 82b. One end of the beams 80a, 80b is fixed to the hand holder 4a, and the other end is fixed to the hand holder 4b. In this case, the hand holder 4 requires some modification. Further, the small articulated robot 1 and the balancer 3 are coupled by a chuck 6 fixed to the member 44 and a coupling member 83 fixed to the input shaft 71. Here, in the third case described above, that is, when operating the input shaft 71 to operate the balancer 3, it is necessary to fix the coupling member 83 to the input shaft 71 as shown in FIG. but,
In the fourth case, that is, when the speed command value is directly input to the drive control device 72, the coupling member 83 can be directly fixed to the beam 80 as shown in FIG.

Next, the control means for the system comprising the above-mentioned small articulated robot 1, balancer 3, and position deviation detection sensor 5 will be described.

First, a control means for operating the balancer 3 by directly inputting a speed command value to the drive control device 72 will be described with reference to FIG. When the operator performs manual operation, the operator gives speed command values in each axis direction on the orthogonal coordinates from the manual device 101. In the control device 7 that controls the small articulated robot 1 and the balancer 3, a target position calculator 103 is operated by pulses from a clock pulse generator 102 that generates pulses at regular intervals. This target position calculator 103 is connected to the manual device 101 described above.
The target position value of the wrist 30 of the small articulated robot 1 is calculated by integrating the speed command value sent from the controller. Next, this position target value is converted by the coordinate converter 104,
The target value θ 1i of the rotation angle of the motor 23 that drives the swivel base 22, the target value θ _2i of the rotation angle of the motor 25 that drives the upper arm 26, and the target value θ _3i of the rotation angle of the motor 28 that drives the forearm ₂₉ . converted. 105 is the encoder 1 directly connected to the above target value and each motor.
This is a speed command value calculator that calculates a speed command value to be input to the motor drive amplifier 107 via the D/A converter 106 from the actual rotation angle of each motor obtained from the counter 110 that counts the pulses generated by the motor. . In addition, the wrist drive motor 31
The target values θ _4i and θ _5i of the rotation angles a and 31b are always constant values in order to keep the wrist posture constant. motor 2
The speed command values V ₁ , V ₂ , V ₃ , V ₄ , V ₅ input to 3, 25, 28, 31a, 31b are the actual rotation angles of the respective motors θ ₁₀ , θ ₂₀ , θ ₃₀ , θ ₄₀ and θ ₅₀ , it is calculated from equation (2).

V _j = K _1j (θ _ji - θ _jp ) ...(2) (j = 1, 2, 3, 4, 5) K _1j is a constant This speed command value is sent to the motor drive amplifier via the D/A converter 106. 107, and the motor drive amplifier 107 feeds back the speed obtained from the tachometer generator 109 directly connected to each motor to control each motor, thereby causing the small articulated robot 1 to operate. Further, the position target value calculated by the target position calculator 103 is stored in the data storage device 112 in response to a position storage command from the teaching device 111 from the operator, and is used as the movement target point when automatically reproducing the motion. The orthogonal coordinate values of

Balancer speed command value calculator 115 is operated by pulses from clock pulse generator 102. This balancer speed command value calculator 115 is sent from the manual device 101. Strain amplifier 117 and A/D for vertical movement speed command value V _Z and strain generated in strain gauge 82 of sensor 5
A balancer speed command value V _B is calculated from the value ΔZ obtained via the converter 118 using equation (3).

V _B =K ₂ V _Z +K ₃ △Z+K ₄ d/dt△Z+K ₅ ∫△Zdt ...(3) However, K ₂ , K ₃ , K ₄ , and K ₅ are proportionality constants.

Here, since the movement speed command value V _Z is a command value commonly given to the small articulated robot 1 and the balancer 3, the speed response characteristics of the small articulated robot 1 and the speed response characteristics of the balancer 3 are equal. , and the internal model of the small articulated robot 1, that is, the horizontal plane virtualized by the coordinate converter 104 and the balancer 3.
coincides with the horizontal plane. That is, if no vertical positional deviation occurs between the balancer 3 and the small articulated robot 1 when the small articulated robot 1 is moved in a horizontal plane, control is possible using only the term K ₂ V _Z. However, in practice, it is difficult to completely match the speed response characteristics of the small articulated robot 1 and the speed response characteristics of the balancer 3. Furthermore, in practice, it is difficult to make the horizontal plane of the internal model of the small articulated robot 1 completely coincide with the horizontal plane of the balancer 3. Therefore, in general, when the balancer speed command value V _B is calculated by V _B = K ₂ V _Z , the actual upward speed of the small articulated robot 1 is v _R and the actual upward speed of the balancer 3 is v _B Then, v _R > v _B or v _B > v _B. Even if the positions of the tip of the small articulated robot 1 and the tip of the balancer 3 are the same before the start of operation, v _R and v _B are different, so the positions of the tip of the small articulated robot 1 and the tip of the balancer 3 are different. The difference ΔZ increases (the steady-state deviation becomes infinite). That is,
With only the term K ₂ V _Z , the steady deviation of the position between the two tips becomes infinite. In this case, the joint between the two will break.

Therefore, in order to make this steady deviation a finite value,
A correction term for K ₃ ΔZ due to the feedback of ΔZ is required. Here, the vertical position of the small articulated robot 1 is X _R , and the vertical position of the balancer 3 is
If X _B , then ΔZ=X _R −X _B. For example, ΔZ
When is positive, since X _R > X _B , it is necessary to increase the balancer speed v _B. This requires a correction term for K ₃ ΔZ of the balancer speed command value V _B.

Furthermore, the term K ₄ d/dtΔZ has the effect of speeding up the response of the balancer 3 due to the correction term K ₃ ΔZ.

d/dtΔZ is a change in positional deviation ΔZ over time. When ΔZ increases, d/dtΔZ is positive, and in this case, the correction term of K ₄ d/dtΔZ increases the speed command value V _B of the balancer 3, which has the effect of speeding up the response of the balancer 3.

Furthermore, the term ∫ΔZdt has the effect of making the steady-state error zero. For example, if you want to stop VZ
= 0 (to simplify the explanation, K ₄ applied to d/dtΔZ is assumed to be 0), so V _B =K ₃ ΔZ.
Normally, a gravitational load is applied in the vertical direction, so when the motor output torque due to the balancer's speed command value V _B balances this gravitational load,
Balancer 3 stops. At this time, position error ΔZ
does not become zero. Therefore, by adding an integral term ∫ΔZdt, as long as there is a position error ΔZ, V _B increases or decreases, and this balances with the gravitational load.
For example, when assembling, it is desirable that the vertical error ΔZ, that is, the positioning error, be zero or as small as possible. In such cases, the term ∫ΔZdt is effective. Therefore, in the balancer 3, the drive motor 64 of the balancer 3 is operated by inputting this balancer speed command value V _B to the balancer drive control device 72 via the D/A converter 116, and the balancer 3 is operated.
follows the small articulated robot 1 and moves. On the other hand, a means for automatically reproducing the movement to the moving target point stored in the data storage device 112 in accordance with the instruction from the teaching device 111 through the above-mentioned manual movement will be described below. First, the orthogonal coordinate values of the movement end target point are retrieved from the data storage device 112, and linear interpolation is sometimes performed between these orthogonal coordinate values and the movement start point in order for the small articulated robot 1 to move on a straight line. A linear interpolator 113 performs calculations to obtain the moving target value every moment using pulses from the clock pulse generator 102. This movement target value is made into the angle target value of each motion axis by the coordinate converter 104,
A speed command value is calculated by a speed command value calculator 105, and the small articulated robot 1 is controlled using the speed command value. On the other hand, the movement target value determined by the linear interpolator 113 is calculated by the speed target value calculator 114.
A difference is made between the movement target value and the movement target value one clock ago, and a vertical movement speed command value V _Z is calculated.
The balancer speed command value V _B is calculated from this movement speed command value V _Z and the value ΔZ of the strain generated in the strain gauge 82 of the sensor 5 obtained via the strain amplifier 117 and the A/D converter 118. By inputting this balancer speed command value V _B to the balancer drive control device 72 via the D/A converter 116, the drive motor 64 of the balancer 3 is operated.
The balancer 3 operates following the small articulated robot 1.

Next, by twisting the wrist 30, the balancer 3
The control means for operating the will be described based on FIG. When the operator performs manual operation, the target position calculator 103 uses the clock pulse generator 102.
The position target value of the wrist 30 is calculated by integrating the speed command value sent from the manual device 101. This position target value is determined by the coordinate converter 104 as a target value θ _1i of the rotation angle of the motor 23 that drives the swivel base 22 , a target value θ 2i of the rotation angle of the motor 25 that drives the upper arm 26 , and a target value θ _2i of the rotation angle of the motor 28 that drives the forearm 29 . is converted into the target value θ _3i of the rotation angle.
Further, the position target value is determined by the operator's teaching device 11.
According to the position storage command from 1, the position is stored in the data storage device 112. On the other hand, the balancer speed command value calculator 115 is operated by the pulse from the clock pulse generator 102, and calculates the vertical movement speed command value V _Z sent from the manual device 101 and the strain generated in the strain gauge 82 of the sensor 5. , the balancer speed command value V _B is calculated from the value ΔZ obtained via the strain amplifier 117 and the A/D converter 118. The twist axis operation target value calculator 119 is
From this balancer speed command value V _B , a target value θ _4i of the rotation angle of the motor 31a that performs the twisting motion of the wrist 30 is calculated using equation (4). However, K ₆ is a proportionality constant.

θ _4i = K ₆ V _B ...(4) The speed command value calculator 105 calculates the above target values θ _1i , θ _2i ,
Encoder 10 directly connected to θ _3i , θ _4i and each motor
Counter 1 that counts the pulses generated from 9
A speed command value to be input to the motor drive amplifier 107 via the D/A converter 106 is calculated from the actual rotation angle of each motor obtained from 10. Note that the target value of the rotation angle of the wrist drive motor 31b is always a constant value in order to keep the posture of the wrist constant. The speed command values input to the motors 23, 25, 28, 31a, and 31b are calculated using equation (2). This speed command value is input to the motor drive amplifier 107 via the D/A converter, and each motor operates.
As the small articulated robot 1 moves, the input shaft 71 of the balancer 3 is rotated by twisting the wrist 30.
is operated, and the balancer 3 follows the small articulated robot 1 and moves. On the other hand, the means for reproducing the movement to the movement target point stored in the data storage device 112 through the above manual movement will be described below. First, the linear interpolator 113 is operated by a pulse from the clock pulse generator 102, and performs linear interpolation between the movement end target point and the movement start point obtained from the data storage device 112, and calculates the movement target value from moment to moment. do. This movement target value is converted by a coordinate converter 104 into a rotation angle target value of each drive motor for the swivel base 22, upper arm 26, and forearm 29, while a speed target value calculator 114 converts the movement speed command value V in the vertical direction. _Z is calculated. A balancer speed command value V _B is calculated from this movement speed command value V _Z and a value ΔZ obtained via the strain amplifier 117 and A/D converter 118 of the strain generated in the strain gauge 82 of the sensor 5. 115, and this balancer speed command value _VB is calculated by the twist axis operation target value calculator 119, and the balancer speed command value VB is calculated by the twist axis operation target value calculator 119.
is converted into the target value θ _4i of the rotation angle. The speed command value calculator 105 performs servo operation on the target value, and controls the motors of each operating axis of the small articulated robot 1. Furthermore, the input shaft 71 of the balancer 3 is operated by a twisting motion of the wrist 30, and the balancer 3 follows the small articulated robot 1 and moves.

In this embodiment, an example has been described in which the input shaft 71 of the balancer is rotated by a twisting motion of the robot's wrist. For a type of rotary variable resistor 70 that is swung in the circumferential direction with respect to the rotation axis, the same effect as described in the embodiment can be produced by vertical bending motion of the robot's wrist. Needless to say, it can be done.

Furthermore, although this embodiment has described a motor-driven balancer, the control method described in the second embodiment can also be used for a balancer driven by a hydraulic pneumatic actuator to configure a system in combination with a robot. , it is possible to control.

As described above, according to the present invention, a light load robot and a balancer are combined, the light load robot positions the balancer, and the position is determined from a sensor provided between the light load robot and the balancer. By correcting the operating speed of the balancer based on the deviation signal, the chuck attached to the tip of the balancer can be positioned with high precision in the vertical and horizontal directions to the moving target point in a light-load robot. , it is possible to handle heavy objects and automatically perform assembly work and processing work that require high-precision positioning. Additionally, since the balancer can be manufactured at a very low cost, a system that combines a light-load robot and a balancer can control complex movements and is less than half the price of a robot that can handle heavy parts. If there is a balancer that can be manufactured and is already available on the assembly or processing line for heavy parts, automation of work that requires high-precision positioning can be achieved simply by introducing a light-load robot and control device. There is an economic effect.

[Brief explanation of drawings]

Fig. 1 is a schematic front view showing an embodiment of a combination of a light load robot and a balancer, Fig. 2 is a perspective view showing the small articulated robot shown in Fig. 1, and Fig. 3 is a front view of Fig. 2. Figure 4 is a diagram showing the wrist drive system of the robot shown in Figure 2, Figure 5 is a sectional view specifically showing the wrist attached to the tip of the forearm of the robot shown in Figure 2, and Figure 6 is a diagram showing the wrist drive system of the robot shown in Figure 2. is a block diagram specifically showing the balancer shown in Fig. 1, Fig. 7 is a principle diagram of the sensor, and Figs. 8, 9, and 10 respectively show the sensor between the robot and balancer shown in Fig. 1. Figures 11 and 12 are diagrams showing one embodiment installed on the
FIG. 3 is a diagram showing an embodiment of a control device according to the present invention. 2...Hand, 3...Balancer, 4...Hand holder, 5...Position deviation detection sensor, 6...Chuck, 7...Control device.

Claims (1)

[Scope of Claims] 1 It has at least three drive sources and at least three encoders, and is controlled so that the position detected by the encoder matches the target position, and the tip of the arm is moved within a horizontal plane by the power of the drive sources. and a positioning robot having at least three degrees of freedom capable of moving in a vertical plane, and a tip equipped with a chuck for gripping parts, which is moved in the vertical direction by the power of a drive source and is movable in the horizontal direction. a balancer capable of transporting a heavy object formed in the robot; a sensor provided at a connecting portion of the robot and the balancer to detect a deviation in the vertical direction between the tip of the robot and the tip of the balancer; Controlling the drive source for the robot based on a command signal to move the tip in the horizontal direction to a target point, and horizontally positioning the chuck 7 at the tip of the balancer connected to the tip of the robot; In order to move the tip of the robot in the vertical direction to the movement target point, the drive source for the robot is driven and controlled based on a command signal, and the movement speed command value in the vertical direction given by the robot control means and detected by the sensor are detected. A speed command value for the balancer is calculated from the deviation, a drive source for the balancer is controlled based on the speed command value, the balancer is moved by the robot, and the chuck is positioned in the vertical direction. 1. A heavy object handling system control device, characterized in that it is equipped with a control device for controlling a heavy object. 2 It has at least four drive sources and at least three encoders, is controlled so that the position detected by the encoder matches the target position, and the tip of the arm moves in a horizontal plane and a vertical plane by the power of the drive sources. The positioning robot has at least three degrees of freedom, and has a wrist at the tip of the arm that can be rotated by the power of the drive source, and a tip equipped with a chuck for gripping parts. a balancer capable of transporting a heavy object, which is moved by the power of a drive source based on a speed command value from a variable resistor provided in the robot, and is movable in a horizontal direction; and a wrist of the robot. and a sensor installed at a connecting portion between the variable resistor of the balancer and the variable resistor of the balancer, the sensor detecting a vertical deviation between the tip of the robot and the variable resistor of the balancer;
In order to move the tip of the robot in the horizontal direction to a target point, the drive source for the robot is controlled based on a command signal to horizontally position the chuck at the tip of the balancer connected to the tip of the robot. In order to move the tip of the robot in the vertical direction to the movement target point, the drive source for the robot is driven and controlled based on the command signal, and the movement speed command value in the vertical direction given by the robot control means and the sensor are A speed command value for the balancer is calculated from the detected deviation, and based on this speed command value, the wrist drive source of the robot is driven to rotate the wrist and vary the variable resistor, thereby driving the balancer. 1. A heavy object handling system control device, comprising: a control device for driving and controlling a source, moving the balancer to follow the robot, and positioning the chuck in the vertical direction.