JPH0725043B2 - Non-contact hand - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact hand which is used by being attached to a manipulator such as a robot for non-contact operation of an object having a ferromagnetic material or a magnet.

[0002]

2. Description of the Related Art Conventionally, as a hand used for a robot or other manipulator, there is a grip type hand.
They use hydraulic, pneumatic or electric motors as a drive source, and operate them by bringing them into contact with the target object. Therefore, it is not suitable for the operation of a material whose surface condition is remarkably changed by contact such as a material just after coating, or an material which is likely to be exploded or cracked by contact. However, if there is a hand that can operate the above things in a non-contact state, it is considered to be extremely useful industrially. In addition, the technology of levitating an object by magnetism to make it non-contact has been known for a long time, and there are bearings and the like that utilize this, but in all of these, the target object is a gap from the magnet. Is very close to 1 to 2 mm or less, and the object itself is not the operation target.

[0003]

In view of the above situation, the present invention utilizes the attractive force of an electromagnet to detect the movable position of the distance between the electromagnet and a ferromagnetic material or an object having a magnet as a part thereof. To provide a non-contact hand for gripping and transferring the object in a non-contact manner by controlling a sensor so that the object can be relatively large and a lifting operation of the object can be stably performed. That is the subject.

[0004]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and its constitution is one to a plurality of electromagnets for attracting an object having a ferromagnetic material or a magnet as a part thereof. And a movable position detection sensor that detects the position of the object, and a control device that controls the electromagnet and the movable position detection sensor, the position of the object is detected by the movable position detection sensor, and the output signal of the sensor By driving the electromagnet, the object is floated and supported in a non-contact state.

[0005]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing a basic configuration of a non-contact hand having one degree of freedom, which is an example of the present invention, FIG. 2 is a diagram showing a basic configuration of a non-contact hand having two degrees of freedom, and FIG. FIG. 4 is a diagram showing a basic configuration of a non-contact hand, FIG. 4 is an overall configuration diagram in which a non-contact hand having one degree of freedom according to an example of the present invention is combined with an articulated robot, and FIG. Schematic diagram of the mechanism,
FIG. 6 is a conceptual diagram of a position detection method using a transmissive optical sensor,
FIG. 7 is a block diagram of an electric circuit, and FIG. 8 is a strong electric circuit diagram around the electromagnet.

As shown in FIG. 1, the basic one-degree-of-freedom non-contact hand of the present invention uses an electromagnet as an actuator and controls the position of an object using a position detection sensor.

A multi-degree-of-freedom non-contact hand is shown in FIG.
As shown in FIG. 3, a plurality of 1-degree-of-freedom non-contact hands are combined and each electromagnet is controlled independently. Three
In a non-contact hand with more than a certain degree of freedom, it is necessary to coordinate the movement of each movable position sensor. For example, in FIG.
To move up and down in the z-axis direction, the point A is moved up and down to move all the sensors A, B, C, and D up and down.
Try to raise. Regarding the rotation around the y-axis, the movements of the sensors C and D are the same as those of the x-axis. A linear PID controller is used to control the electromagnet, and the nonlinearity of the electromagnet is P
It should be compensated by adjusting the ID gain. Up to 2 degrees of freedom can be adjusted relatively easily by manually adjusting the gain,
Since the adjustment becomes complicated when the degree of freedom is 3 or more, the gain may be automatically tuned.

The operation of the present invention will be described below with reference to FIG. In the figure, 1 is an electromagnet attached to a flange F of a robot, 2 is a movable position detection sensor attached so as to be vertically movable by a feed mechanism 3, 4 is a controller, 5 is a power amplifier, 6 is a ferromagnetic material or magnet 6a.
, Which is a part of the controller 4 and uses the position of the object 6 detected by the sensor 2 as a feedback signal.
Change the deviation from the position command given internally into a control signal,
The power amplifier 5 amplifies and drives the electromagnet 1 to levitate and support the object 6. The position of the object 6 can be changed by changing the position command value of the controller 4, but since the movable range thereof is as narrow as 2 mm, the method of changing the position of the sensor 2 is adopted. In order to bring the object 6 from the ground to the air in a levitation-supported state, after moving the non-contact hand to the sky above the object 6, the sensor 2 is lowered to a position where the object 6 is detected, and from that point, the control of the electromagnet 1 is started. And the sensor 2 is gradually raised. In addition, the integral gain is set to a small value in order to operate stably with respect to the change in the weight of the object 6 when it is levitated. After the levitation of the object 6 is completed, the integral gain is increased. In addition to this, as a gain adjustment rule, when the weight of the object 6 is small or the distance between the object 6 and the electromagnet 1 is short, the proportional gain or the differential gain is decreased, and in the opposite case, the gain adjustments are also reversed. To

A specific example of the present invention will be described with reference to the drawings. a Device Configuration FIG. 4 is an overall configuration diagram of a state in which a non-contact hand with 1 degree of freedom, which is the basis of an example of the present invention, is combined with an articulated robot, and the position of an object 6 is measured by a position detection sensor 2. Then, the output of the sensor 2 is fed back to the controller 4. The PID gain adjusting volume 7 of the controller 4 is set to be adjustable by the operator. The output of the controller 4 is current-amplified by the power amplifier 5 to drive the electromagnet 1 to attract and levitate the object 6 in a non-contact state. The feed mechanism 3 for moving the sensor 2 is driven by the motor 8, and the driving moves the sensor 2 up and down. The motor 8 is driven by the driver 10 amplifying the output of the position controller 9. The drive system of the sensor 2 is the feed amount detector 11
The position control system that amplifies the deviation from the command value of the feed amount indicator 12 is configured as the feedback amount. The sensor position control system is independent of the controller 4,
Although it is complicated to adjust the PID gain of the controller 4 depending on the position of the sensor, it is also possible to reflect the sensor position information on the controller 4 and perform auto tuning. The feed mechanism including the sensor drive motor 8 is also attached to the flange F for attaching the electromagnet 1 to the tip of the manipulator.

B Position Detection Sensor FIG. 5 shows an example of the position detection sensor 2, which includes an LED
13 and the photodiode 14 are attached to the sensor attachment jig 15 to form a transmission type. In order not to respond to visible long noise such as fluorescent light, the LED 13 is used in the infrared region, and the photodiode 14 is also adapted to it. As shown in FIG. 6, the position detection utilizes a change in the amount of light that strikes the light receiving surface of the photodiode 14 depending on the position of the object 6. Therefore, the detection range is narrow and is considered to be approximately proportional to the length of the light-receiving surface of the photodiode 14, which is 2 mm in the embodiment. The transmissive sensor has the advantage that it can be of any shape as long as the object is optically opaque, and is stable because it is not easily affected by the reflection characteristics of the object surface. As a result, the range of position detection can be expanded. The position detected by this sensor is not an absolute position from the electromagnet 1 to the object 6 but a relative position.
In addition to the transmissive optical sensor, a reflective optical sensor, an eddy current position sensor, or the like may be used as the position detection sensor 2 depending on the shape of the object 6 and the degree of freedom of the hand. When using the eddy current type position sensor, it is necessary to process the sensor output so as not to be affected by the magnetic field of the driving electromagnet.

C Control Circuit FIG. 7 is a block diagram of an electric circuit.
An ID control circuit was constructed. Transfer function G (s) of control circuit
Is the following equation, where Kp is the proportional gain, Ki is the integral gain, and Kd is the differential gain. However, s is a Laplace operator. G (s) = Kp + Ki · 1 / s + Kd · s The control may be performed by software using a personal computer or the like.

D Power Supply Method The power supply method to the electromagnet 1 uses PWM (pulse width modulation method) to reduce the heat loss of the amplifier. The pulse cycle is about 2 KHz. In the embodiment, DC23V is used as the power source for driving the magnet, and a maximum current of about 5 A can be stably supplied to the electromagnet coil. As shown in FIG. 8, the diode 17 mounted in parallel with the electromagnet coil 16 is used as a flywheel diode.
Even if the coil is pulse-driven by this diode 17,
A direct current flows through the coil. A bipolar power transistor module 18 is used as a switching device in the output stage.
You may use T etc. When the power MOSFET is used, the pulse cycle can be increased to about 10 to 20 KHz, which enables more smooth power supply.

E Electromagnet In the embodiment, a bar magnet is used to simplify the device,
An iron rod having a diameter of 10 mm and a length of 200 mm was used for the iron core 1a, and an appropriate taper was attached to the tip facing the object.
The excitation coil 1b is a formal wire 600 mm in diameter 600
It wound up. The winding resistance was 1.3Ω. Furthermore, when making a strong magnetic field, increase the number of turns of the coil 1b,
Further, it is also necessary to increase this so that the iron core 1a is not magnetically saturated. The magnet type is not limited to bar magnets,
A more suitable shape and type of magnet can be considered.

Actually, using the above-mentioned non-contact hand with 1 degree of freedom, a sphere having a diameter of 38 mm and a weight of about 25 g coated with a ferromagnetic material, or an iron having a diameter of 17.5 mm and a weight of 21.7 g. When the sphere is sucked, the distance from the electromagnet 1 is 4-8 mm
It was confirmed that it is possible to change the position between the above, and it is possible to levitate the above-mentioned object placed about 10 mm below the electromagnet 1 to the control position. Also, when this non-contact hand was attached to an articulated robot and a movement test was performed, the hand showed a swaying motion due to the degree of freedom of the hand, but the robot showed a sudden movement. Unless it was done, the object could be stably supported by levitation and transported.

[0015]

The present invention is as described above, and it is possible to suspend and support an object having a ferromagnetic material or a magnet in its part as if it were suspended from above, and without contact. For example, it is suitable as a hand attached to a robot or other manipulator in order to operate things such as those that have just been painted and whose surface condition changes significantly, or things that are prone to explosion or cracks due to contact. Is.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a non-contact hand having one degree of freedom according to an example of the present invention.

FIG. 2 is a diagram showing a basic configuration of a two-degree-of-freedom non-contact hand.

FIG. 3 is a diagram showing a basic configuration of a three-degree-of-freedom non-contact hand.

FIG. 4 is an overall configuration diagram of a state in which a non-contact hand with one degree of freedom according to an example of the present invention is combined with an articulated robot.

FIG. 5 is a schematic view of a method of attaching a sensor and a feeding mechanism.

FIG. 6 is a conceptual diagram of a position detection method using a transmissive optical sensor.

FIG. 7 is a block diagram of an electric circuit.

FIG. 8 is a high-voltage circuit diagram around an electromagnet.

[Explanation of symbols]

 1 Electromagnet 1a Iron core 1b Electromagnetic coil 2 Moving position detection sensor 3 Feed mechanism 4 Controller 5 Power amplifier 6 Object with ferromagnetic material or magnet in part 6a Ferromagnetic material or magnet in object 7 PID gain adjustment volume 8 Sensor drive Motor 9 Position controller 10 Driver 11 Feed amount detector 12 Feed amount indicator 13 LED 14 Photodiode 15 Sensor mounting jig 16 Electromagnetic coil 17 Diode 18 Power transistor module R Robot F Robot F flange

Claims (1)

[Claims] 1. One or a plurality of electromagnets for attracting an object having a ferromagnetic material or a magnet in its part, a movable position detecting sensor for detecting the position of the object, and the electromagnet and the movable position detecting sensor are controlled. A control device, the position of the object is detected by the movable position detection sensor, an electromagnet is driven by an output signal of the sensor, the object is floated and supported in a non-contact state, and the sensor is moved. A non-contact hand characterized in that it is made to function as a robot hand by manipulating the object by means of the above.