JPH0531688A - Conveying device - Google Patents

Abstract

PURPOSE:To provide a device capable of making conveying operation while a load weight and moment are accurately detected, in a device to convey an object to be conveyed. CONSTITUTION:A slewing table 5 is located on a moving truck 4, and first and second arms 6 and 7 are located on the slewing table. The upper surface of the second arm forms a placing part for an object to be conveyed and a pressure detector 8 is installed on the surface thereof. A moment load exerted on first and second rotation arm shafts have respective gravity balanced with each other by means of force generating means 14 and 18. Since employment of this support method causes compensation of the weight of a substance to be conveyed by means of a conveying device, the substance to be conveyed is conveyed without being followed by high vibration and quality thereof is prevented from being damaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for carrying an object under a gravity action environment, and by generating a gravity balance force corresponding to its own weight, without vibrating an object to be carried,
The present invention relates to a device that can be transported without impairing quality.

[0002]

2. Description of the Related Art Conventionally, as a device for transporting a person to be transported, which is used in a gravitational action environment, as disclosed in Japanese Examined Patent Publication No. 2-31975, a flat plate that moves between a person and a bed rather than a moving bed. A device for carrying by inserting and pulling out the was described.

Further, as disclosed in Japanese Patent Laid-Open No. 62-79058, there has been described an apparatus for carrying a person on a flat plate at the tip of a vertical articulated robot provided in a mobile robot.

A vertical articulated robot as disclosed in Japanese Patent Publication No. 63-51831 is widely used as a device for carrying heavy objects used in a gravity action environment.

[0005]

The first prior art relating to a device for carrying a carried person is a method of inserting a flat plate between the carried person and the bed, so that a hard flat plate is the arm part of the carried person. Alternatively, since it directly hits the flank, there is a problem of causing pain.

The second prior art has a structure in which a person to be transported is placed on the tip of a robot arm. However, directly transporting a person with a robot hand gives a fear to the person to be transported. There is.

The third prior art is a structure in which an object is attached to the tip of a vertical articulated robot. This type of robot has a small transportable weight with respect to its weight, and is 60 kg like a human. The vertical articulated robot having a small load capacity is large and usually weighs 500 kg or more, and is not suitable for use at home or in a hospital.

As described above, in the prior art, since the work of placing the person to be carried, heavy objects, etc. on the apparatus is performed by a clumsy machine, the person to be carried is uncomfortable and
It was large. Further, in order to prevent the carried person from feeling uncomfortable, the carrying method is used by the carrying person directly, but there is a problem that the carrying person is required to have a great carrying force and causes physical pain. .. An object of the present invention is to provide a small and lightweight carrying device that can reduce the burden on the carrier without causing discomfort to the carrier.

[0009]

In order to achieve the above object, the present invention employs the following technical means.

(1) In order to perform a dexterous motion, the movement of the object by the arm of the carrier is assisted by a robot for gravity balance compensation.

(2) In order to have a compact and lightweight structure, a structure in which a hydraulic cylinder having a large output / weight ratio is used as the force generating means of the gravity balance device and a hydraulic source is also incorporated.

(3) The displacement of the force generating means of the gravity balance device and the desired generated force have a proportional relationship so that the position / force control can be easily realized.

[0013]

The basic operation principle of the carrier or the object carrier according to the present invention will be described with reference to FIGS. FIG. 18 shows a simplified explanatory view of the carrying device of the present invention,
19 shows a configuration of a carried person's lifting work using the carrying device of FIG. 18, and FIG. 20 shows relative positions of the carrying person, the carried person, and the carrying device in the lifting work of FIG. 21 shows a movement operation using the carrying device of FIG. 18, FIG. 22 shows a structure of a gravity balance device of a first arm, and FIG. 23 shows a structure of a gravity balance device of a second arm. 24 shows the configuration of the control system of the gravity balance device, and FIG. 25 shows the gravity balance effect of the gravity balance device.

First, the construction of the carrying apparatus of the present invention will be described with reference to FIG. In the figure, the moving carriage 4 has wheels 1
0 is provided, and the wheel 10 is configured so that its rotational operation can be locked and unlocked. The movable carriage 4 is provided with an articulated robot having rotational degrees of freedom in three directions indicated by arrows in the figure. In the robot, the swivel base 5 can rotate about an axis in the gravity action direction with respect to the moving carriage 4, and the first arm 6 can rotate in the gravity action direction with respect to the swivel base 5. The second arm 7 provided at the tip of 6 is rotatable in the gravity acting direction with respect to the first arm 6. On the upper surface of the second arm 7, pressure detectors 8 including piezoelectric elements are arranged in a matrix in the longitudinal direction and the orthogonal direction. The carrier 2 fixes the front part of one arm to the second arm 7. When the object or the person to be transported 3 is placed on the arm, the pressure detector 8 detects the pressure at each position on the second arm 7, and based on the detected pressure value, the formula (1), the formula ( By the calculation shown in 2), the acting load and the acting moment around the arm rotation axis can be obtained.

[0015]

[Equation 1]

[0016]

[Equation 2]

Here, p: pressure, x direction: arm longitudinal direction, y direction: arm longitudinal direction and orthogonal direction, m: number of detectors in x direction, n: number of detectors in y direction, ΔS: grid of pressure detectors. Area.

Next, based on this detection result, the first arm 6
And a desired generated force of the gravity balance device corresponding to the arm position (force generation device position) of each force generation means (not shown) of the gravity balance device of the second arm 7 and calculates the force based on the position command and the force command. Controls the generating means. Mobile trolley 4
Can extend the auxiliary leg 9 so as not to fall when a load is applied to the second arm 7.

Next, an operation example of the carrying device 1 is shown in FIG.
This will be described with reference to FIGS. FIG. 19 shows a futon 11
On the upper surface of the second arm 7 of the carrier 1,
Insert the carrier / robot integrated arm with one arm of the carrier 2 fixed between the futon 11 and the carrier 3 to
Takes a posture capable of lifting the transported person 3. At that time,
The perspective view is shown in FIG. 20. The carrier / robot integrated arm (2a, 1) is inserted at a position B, which is a distance l ₁ shorter than the center of gravity G of the person to be transported 3, and a distance l ₂ longer than the center of gravity G.
By inserting the arm 2b of another carrier into the distant position A, the forces Fa and Fb acting on the points A and B are calculated by the formula (3), the formula
As shown in (4), in the case of l ₂ >> l ₁ , the force acting on the point A can be reduced, and the force acting on the point B can be compensated by the gravity balance device of the robot. This makes it possible to carry the transported person without causing discomfort.

[0020]

[Equation 3]

[0021]

[Equation 4]

Next, the operation of the robot when moving the moving carriage will be described with reference to FIG. Transportee 3
Is arranged on the center of gravity of the moving carriage 4 which does not fall down, the auxiliary legs 6 are folded, the carrier 2 unlocks the wheels 10, and the moving carriage 4 is pushed or the electric moving mechanism is operated, so that it is desired. Move in the direction of.

Next, the structure and operation of the gravity balance device of the present invention will be described with reference to FIGS.
FIG. 22 shows the structure of the gravity balance device of the first arm. Two sub-arms 1 on the rotation axis at the base of the first arm 6
3a and 13b are provided with a phase difference of 90 °, and the tip ends of the sub-arms 13a and 13b and the two fixing points of the swivel base 5 are force generating means 14a and 14b such as hydraulic cylinders.
Are connected by. FIG. 23 shows the configuration of the gravity balance device for the second arm. Rotational transmission from the rotation axis of the root of the second arm 7 to the root of the first arm 6 is performed by parallel links 17a and 17b having a double link structure,
Two sub-arms 16 are provided on the rotating shaft guided on the swivel 5.
a and 16b are provided with a phase difference of 90 °, and the tip of the sub-arm and two fixed points of the swivel base are connected by force generating means 18a and 18b such as a hydraulic cylinder. Here, the reason why two sub-arms are used for the parallel link of the double link structure and the gravity balance device is to eliminate the posture in which the force cannot be generated.
Since the relationship between the linear displacement of the force generating means of the gravity balance device shown in the figure and the desired linear power has a substantially proportional relationship, position control is performed using a proportional control system as shown in FIG. As a result, the force of the cylinder can be controlled at the same time. Further, the gravity compensation effect at that time is shown in FIG. 25. The gravity compensation torque M substantially matches the gravity load moment M ₀ of the rotating shaft with respect to the attitude angle of the arm, and a good gravity compensation effect is obtained. can get.

As described above, by using the device for transporting an object to be transported according to the present invention through a carrier, it is possible to realize an operation in which the burden on the carrier is reduced by using a small and lightweight device in the transportation work.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a carrier or object carrying device and a control system therefor according to the present invention will be described with reference to FIGS. 1 shows a basic configuration diagram of a carrying device of the present invention, FIG. 2 shows another basic configuration diagram of the carrying device of the present invention, and FIG. 3 shows a gravity balance of a first arm of the carrying device of FIG. FIG. 4 is a structural diagram of the device, FIG. 4 is a structural diagram of a gravity balance device of the second arm of the carrying device of FIG. 1, FIG. 5 is a structure of a hydraulic drive system, and FIG. , Shows a block diagram of a force control system, FIG. 7 shows an operation mode of a carrying device when carrying a person to be carried, FIG. 8 shows a work procedure of a person's transfer work, and FIG. FIG. 10 shows a transfer floor work content diagram, FIG. 10 shows a flowchart of a carrying device teaching operation, and FIG. 11 shows a flowchart of a carrying device regeneration operation.

First, the structure of the carrying device will be described with reference to FIG. The carrier device arm portion is required to have a wide motion range from downward to upward in view of the above-mentioned work content. The carrier device arm portion is provided with a swivel base 5 rotatably provided with respect to a moving carriage 4, and a first arm 6 rotatably provided in a gravity acting direction. A second arm 7 is provided at the tip of the first arm 6 so as to be rotatable in the gravity acting direction. In the gravity balance device, both the first arm and the second arm are provided with two sub-arms having a phase difference of 90 ° on the rotating shaft in order to eliminate the posture in which the force cannot be generated, as described in "Operation". A direct-acting force generating means such as a hydraulic cylinder is provided between the revolving base and the position / force control.

Hydraulic cylinders 14a, 14b, 18a, 1
8b is driven as follows. The oil in the oil tank 19 is guided to the servo valve 21 via the pump 20 (including the motor). The servo valve is a drive that realizes the desired piston position and force (corresponding to the pressure difference between both chambers) by adjusting the opening of the chamber to both chambers partitioned by the pistons of the hydraulic cylinder. It is a system. Small pressure detectors 8 are provided in a matrix on the upper surface of the second arm 7 on which the transported object is placed, and the load F ₂ acting on each robot axis of the transported object from the pressure detection value of each part. And moment M ₂₀ formula
It can be calculated using (1) and equation (2).

Further, the movable carriage 4 is provided with auxiliary legs 9 for preventing it from tipping over so that the movable carriage 4 can be put in and taken out. Further, a battery 22 is provided inside the swivel base 5 to supply electric energy necessary for operating a motor, a detector and the like. Further, although not shown, a central processing unit, a digital converter for detector output, a motor driving force command generating unit, a servo amplifier, etc. are provided.

Next, another configuration of the carrying device of the present invention will be described with reference to FIG. This device has the same structure as that of the carrying device arm part as shown in FIG. 1, and uses a rotary type motor as a drive source of its gravity balance device. The first arm 6 is balanced by the first motor 32, and the second arm 7 is balanced by the second motor 33. Therefore, gravity balance can be realized by applying the moments M ₁₀ and M ₂₀ shown in the equations (7) and (8) described below to the first motor 32 and the second motor 33. Although not shown, the motors 32 and 33 are provided with position detectors and force detectors.

Next, with respect to the carrying device of FIG. 1, details of the gravity balance device of the first arm will be described with reference to FIG. The load acting on the first arm 6 is the sub arm 13
Via a, 13b, one end is supported by force generating means, one end of which is fixed to the swivel base, for example, hydraulic cylinders 14a, 14b. A position detector including, for example, a direct-acting potentiometer is provided on the swivel base side of the hydraulic cylinders 14a and 14b. The hydraulic cylinders 14a and 14b detect pressure as force detection means in both chambers partitioned by pistons. A vessel is provided. The hydraulic drive system is as described above. Next, the gravity balance device for the second arm will be described with reference to FIG. The rotation of the second arm 7 is performed by the sub arms 15a, 15
b, it is converted into rotation of the sub arms 16a and 16b around the first arm axis of the swivel base via the parallel links 17a and 17b. Hydraulic cylinders 18a and 18b are provided as force generating means between the tips of the sub arms 16a and 16b and the swivel base. A position detector is provided on the side opposite to the sub-arm of the hydraulic cylinder, and a pressure detector is provided as force detecting means in both chambers of the piston of the hydraulic cylinder.

The gravity balance device is defined by the equations for the angles φ and ζ formed by the first arm and the second arm with respect to the horizontal direction.
For the gravity load moment shown in (7) and equation (8),
This is a device that generates and balances the compensating force as shown in equations (5) and (6).

[0032]

[Equation 5]

[0033]

[Equation 6]

[0034]

[Equation 7]

[0035]

[Equation 8]

Here, the force generating means 14a, 14b, 18
Sub-arms 13a and 13b radius r ₁ and sub-arms 16a and 16 are defined with the generated forces of a and 18b as F ₁ , F ₂ , F ₃ and F _4.
b radius r ₂ , angles formed with the vertical direction of the force generating means φ ₁ , φ ₂ ,
ζ ₁ , ζ ₂ , l ₁ : position vector from the uniaxial rotation axis to the center of gravity of the first arm, l ₂ : position vector from the biaxial rotation axis to the position of the center of gravity of the second arm, W ₁ : weight vector of the first arm , W _{2 is} the weight vector of the second arm, a _{1 is} the position vector from the uniaxial rotation axis to the biaxial rotation axis, j is the rotation axis direction vector, and k is the vertical direction vector. Next, the structure of the hydraulic drive system will be described with reference to FIG. In the hydraulic cylinders 14 and 18, oil is supplied to the servo valves from the oil tank 19 via the pump 20, and the spool 23 is directly driven by the servo valve drive motor to change the flow rate supplied to both chambers of the cylinders. It is driven by the fluid force generated thereby.

The pressures in both chambers are converted into electric signals by the pressure detectors 1 and 2, and the signals are digitally converted, and the direct power can be calculated as the product of the differential pressure and the cross-sectional area. The position detector is capable of giving the absolute position of the piston. For example, it is detected by a potentiometer and digitized by A / D conversion, and a current command of the spool drive motor is generated based on the force and position control law.

Next, the structure of the control system of the above-mentioned carrying device will be described with reference to FIG. In this control system, it is necessary to control both position and force. Therefore, the position control is performed based on the deviation from the position detection value based on the interpolated position command at each time point of each sampling period generated after the point teaching described later. In addition, at the time of each sample period, from the output of the pressure detector on the second arm, the formula (5) and the formula (7), the formula (6)
By setting equation (8) as an equation, the force command is obtained as shown in equations (9) and (10).

[0039]

[Equation 9]

[0040]

[Equation 10]

This is because the moment multiplied by sin and cos acts as shown in the equations (5) and (6).
This means that the optimum force that can be generated for each posture is required. Although the position command and the force command are obtained in this way, it is necessary to control them together. Therefore, the command is modified so that the weights of the position control and the force control become 1 in total, and the control is performed based on each control law. The method was used.

Next, with reference to FIG. 7 to FIG. 11, a method of performing work will be described taking a person's transfer work as an example. Figure 7
FIG. 8 shows a work mode when a person to be transported is carried out using the carrier device of FIG. 1, FIG. 8 shows an overall flow of the work, and FIG. 9 shows the contents of the work. Here, the transfer work we are thinking about is
This is a work of lifting a person to be laid on his / her back on the first bed and laying it down on his / her back on a second bed placed at a distant position.

The positional relationship between the carrier, the person to be carried, and the carrier will be described with reference to FIG. The transported person 3 is lying on his back and cannot stand up by himself. Carrier 2
Places one arm on the carrier second arm 7 and lifts the vicinity of the center of gravity of the person 3 to be carried from below. Then, the other arm is lifted away from the center of gravity of the transported person 3, for example, near the shoulder. With such an operation posture, most of the weight of the person 3 to be transported can be configured to act on the side of the transport device. In addition, the person to be transported 3 feels a pleasure because he is held by a person's real arm. The carrier has a structure in which a gravity balance device is built in, a gravity compensating force is generated, and the carrier is not burdened.

Next, the contents of the floor transfer work will be described (see FIGS. 8 and 9).

First, the carrier teaches the operation of the carrier arm section on the first bed or an unmanned bed of the same type. Here, direct teaching is performed by giving the control system a large compliance. The teaching is to teach several points at a short ascending interval from the position where the person being carried lays on his / her back, and then to the position holding point where the movable person's center of gravity is almost on the center of gravity axis of the moving carriage. Teach the middle and end points of. At this time, the operation speed is also taught. It is necessary to teach some points in the vicinity of the place to be lifted here, which is the same as so-called ground cutting in crane work, and it makes the transported person uncomfortable unless careful force control is performed until lifting from the bed, This is because it may cause physical distress to the carrier.

Here, the operation from the first bed to the position holding position will be called (1), and the operation from the position holding position to the second bed after the moving operation of the moving carriage will be called (2).

Next, the carrier inserts the carrier device arm portion under the carrier. Even in this state, the control system has a large compliance. Next, the control system is switched to the position / force control system, and the reproducing operation (1) is started. It is moved to the first teaching point by position / force control. When the person moves the arm following the force generated by the gravity balance device at that time, the person can smoothly reach the second, third, ..., Teach points and reach the position holding position.

The dolly moves by performing an operation of pushing the moving dolly from the movement start position.

Next, a regenerating operation (2) for lowering the person to be transported to the second bed is performed, and when the vehicle is lowered to the bed, the control system having a large compliance is switched to and the transportation device arm is retracted from the lying person.

This is a series of operation flow. Detailed flows of the teaching operation and the reproducing operation are shown in FIGS. Here, during the reproducing operation, processing for generating the force command shown in the above equations (9) and (10) is performed based on the detector information for each sampling period.

[0051]

[Equation 9]

[0052]

[Equation 10]

This sampling period is determined by the arithmetic capacity of a central processing unit (not shown) and is a number such as 30 (msec).

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. In this embodiment, attention is paid to the fact that the displacement of the hydraulic cylinder and the generated force are in a substantially proportional relationship, and the control system and the detector are simplified. 12 shows a block diagram of a control system of the carrying device of the present embodiment, FIG. 13 shows a designing method of force generating means in the carrying device of the present embodiment, and FIG. 14 shows a carrying device of the present embodiment. The structure of a hydraulic drive system is shown.

Due to the above-mentioned properties, the force command as shown in equation (11) can be generated by multiplying the deviation between the position command and the output of the position detector by the proportional gain.

[0056]

[Equation 11]

Here, in determining the proportional gains K ₁ , K ₂ , K ₃ and K ₄ , the force generating means 14a, 14b, 18a, 1
The displacement from the parallel position of 8b is Δx ₁ , Δx ₂ , Δx ₃ , Δ
When x ₄ is set, the equations (9) and (10) are taken into consideration and the equations (12) to (15) are determined.

[0058]

[Equation 12]

[0059]

[Equation 13]

[0060]

[Equation 14]

[0061]

[Equation 15]

By thus determining the proportional gain, the control system shown in FIG. 12 which is simplified as compared with the control system shown in FIG. 6 is obtained.

A problem in constructing this control system is that the obtained proportional gain must not destabilize the control system.

This can be prevented by determining the upper limit of the proportional gain so that the gain margin of the open loop transfer characteristic does not become negative as shown in the equation (16).

[0065]

[Equation 16]

Further, in determining the dimensions of the sub-arm and the hydraulic cylinder, it is desirable to design according to the flow shown in FIG. First, the dimensions of each part such as the sub arm length and cylinder length are determined, and the proportional gain over the entire operating region when the standard load is mounted at a fixed position on the second arm is obtained by the least square method, and the obtained control system is If stable, by updating the dimensions of each part and designing to be stable,
Sufficient position / force control is possible without destabilizing the control system over the entire operating region.

Next, FIG. 14 shows the structure of the hydraulic drive system when this control system is used. From this, by using this control system, the hydraulic cylinder does not require force feedback, and therefore there is an advantage that the pressure detector does not need to be mounted and the mechanism is simplified.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. In this embodiment, the moving carriage is electrically driven, and the moving operation can be performed without relying on human power. FIG. 15 shows the structure of the electric mobile trolley,
16 shows a block diagram of the control system, and FIG. 17 shows
The operation flow is shown.

First, the structure of the electric movement mechanism will be described with reference to FIG. The electric energy of the battery 28 is applied to the motors 27 and 30 via the inverter circuit 25 based on the command from the control device 24. The straight-ahead movement of the moving carriage is realized by the drive wheels 26a and 26b, and the bending movement is realized by the steered wheels 29. The drive wheels 26a, 26b and the steered wheels 29 are transmitted from the motors 27, 30 via a deceleration power transmission mechanism. When the moving carriage 4 travels on the reflection tape 32, the optical detectors 31 arranged at the front and rear portions of the moving carriage 4
The reflective tape position is detected by a and 31b, and the wheel is driven while correcting the deviation. When traveling in a place where there is no reflection tape, position control is performed by a motor or a wheel rotation position detector.

The control system of each wheel is constituted by an independent position control system as shown in FIG. FIG. 17 shows a work flow when the electric mobile cart is applied to the floor transfer work shown in FIG. 8. Operation during robot teaching (1),
The teaching process of the moving carriage is newly added during (2).

By using the transporting device having such a configuration, the transporter can realize the transfer operation without feeling any pain in every process.

[0072]

Since the present invention is constructed as described above, it has the following effects.

(1) When a carrier carries a carried person by using a carrying device for gravity balance, the carrier does not feel any physical pain, and the carried person does not feel fear. Transport work can be realized.

(2) By adopting a double sub-arm structure for the gravity balance device, there are no places where force cannot be generated,
Smooth operation can be realized.

(3) Force control can be realized only by performing position control by using a force generating means of the gravity balance device that has a linear relationship between displacement and generated force.

(4) Since the transport device has the pressure detectors arranged in a matrix on the upper surface of the second arm, it is possible to detect the load and the moment in real time in consideration of the distributed load action condition, and to obtain an accurate gravity balance. This makes it possible to carry an object without vibrating it and without sacrificing quality.

(5) By electrifying the moving carriage,
It can alleviate the physical distress of the carrier in all movements.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a carrying device of the present invention.

FIG. 2 is a perspective view of another embodiment of the carrying device of the present invention.

3 is a block diagram of a gravity balance device of a first arm of the carrier device of FIG.

4 is a block diagram of a gravity balance device for the second arm of the carrier device of FIG. 1. FIG.

5 is a block diagram of a hydraulic drive system of the carrying device of FIG. 1. FIG.

FIG. 6 is a block diagram of position / force control in an operation reproduction mode.

FIG. 7 is a perspective view of a work mode when the transporting device of FIG. 1 is used for a floor transfer work.

FIG. 8 is a flowchart showing a work procedure for a person's transfer work.

FIG. 9 is an explanatory diagram of work contents of a person's transfer work.

FIG. 10 is a flowchart of a robot teaching operation.

FIG. 11 is a flowchart of a robot reproducing operation.

FIG. 12 is a block diagram of a control system of the carrying device according to the second embodiment of the present invention.

FIG. 13 is a flowchart of the force generating means of the gravity balance device of the carrier device.

FIG. 14 is a block diagram of a hydraulic drive system of a carrying device according to a second embodiment of the present invention.

FIG. 15 is a perspective view of a moving carriage according to a third embodiment of the present invention.

16 is a block diagram of a control system of the mobile cart shown in FIG.

FIG. 17 is a flowchart of an operation procedure of a carrying device including the moving carriage of FIG. 15.

FIG. 18 is a simplified explanatory view of the carrying device of the present invention.

FIG. 19 is an explanatory diagram of a configuration of a work of lifting a person to be carried using the carrying device of FIG. 18;

20 is an explanatory view showing relative positions of a carrier, a person to be carried, and a carrier device in the lifting operation of FIG.

FIG. 21 is an explanatory view of a moving operation using the carrying device of FIG. 18.

FIG. 22 is an explanatory diagram of the structure of the gravity balance device of the first arm.

FIG. 23 is an explanatory diagram of a structure of a gravity balance device for the second arm.

FIG. 24 is a block diagram of a control system of the gravity balance device.

FIG. 25 is an explanatory diagram showing a gravity compensation effect of the gravity balance device.

[Explanation of symbols]

4 ... Movable carriage, 5 ... Revolving base, 6 ... First arm, 7 ... Second arm, 8 ... Pressure detector, 9 ... Auxiliary leg, 13, 15, 1
6 ... Sub arm, 14 ... Force generating means, 17 ... Parallel link, 18 ... Force generating means, 19 ... Fluid tank, 20 ... Pump, 21 ... Servo valve.

Claims (1)

Claim: What is claimed is: 1. In a carrying apparatus, a movable carriage, a swivel rotatable on the movable carriage around an axis in the gravity acting direction, and a gravity acting direction provided on the swivel. It comprises a rotatable first arm and a second arm capable of placing an object to be transported on its upper surface rotatable about the axis of the first arm in the direction of gravity action. A gravity balance device is provided between the bases and between the second arm and the swivel base, and a detector for detecting the load of the transported object and the arm rotating shaft action moment is provided. Transporting device.