JPS63237883A - Chuck drive - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a chuck drive device that is used, for example, in a hand of a robot or the like, and is particularly used for gripping soft objects with appropriate pressure.

(Prior Art) Conventionally, a chuck drive device used in a robot hand, for example, to grip a particularly soft object, is generally equipped with a precise and expensive pressure sensor. A control method was used that detected the pressure during the process of grasping an object and held the pressure when it reached a set pressure.

(Problems to be Solved by the Invention) According to the above-mentioned conventional chuck drive device for gripping particularly soft objects, the pressure when gripping the object is detected by a pressure sensor, but the appropriate pressure at this time is The set value is the appropriate pressure when gripping the object from the specified direction, so if you change the direction in which you grip the object, you need to change all related setting data. However, there was a problem in that it took a lot of time to change the setting data.

In addition, the pressure sensor is often damaged due to direct contact with the object, and a lot of time is spent adjusting it when replacing it, and the pressure sensor is expensive, so it is difficult to drive the There was a problem that the cost of the device was high.

Therefore, the technical object of the present invention is to solve the above-mentioned conventional problems by providing a chuck drive device that can grip any object from any direction with an appropriate pressure without using a pressure sensor. It is.

(Means for Solving the Problems) The technical means for solving the above problems is to use a chuck driving device to drive a chuck for gripping an object of any shape and hardness from any direction, and the chuck section. A drive unit that detects the motor and the drive current applied to the motor and outputs a signal corresponding to the detected current! 1Ill current detection means; torque setting means for setting the output torque of the motor when the chuck portion grips the object;
A signal output from the drive current detecting means is inputted to recognize the output torque of the motor when the chuck part grips the object, and a drive power is generated for causing the motor to intermittently output the required torque. and drive control means for outputting to the motor.

(Function) According to the chuck drive device having the above configuration, the drive control means receives, from the drive current detection means, drive power for causing the motor to output the required torque set by the torque setting means. Input the signal and output torque! The chuck section controls the object by gripping the object with a predetermined average force.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram that does not show the overall configuration of the chuck driving device. As shown in FIG. 1, there is a chuck part 1A that grips the object M to be grabbed (for example, an egg) while applying a predetermined pressure by contacting the object M, and supports this chuck part 1A and drives it to open and close. A chuck 1 formed of a chuck main body 1B having a mechanism is driven by a DC motor (direct current motor) 3 via a speed reducer 2. A brake (not shown) is attached to the DC motor 3, and the brake is released when driving power for forward or reverse rotation is supplied to the DC motor 3. Further, a detected object 4A having one or more magnets arranged on the outer peripheral surface of a disc is attached to the rotating shaft of the DC motor 3, and the magnetism generated from the magnet of this detected object 4A is detected. An encoder 4 made of, for example, a Hall element for outputting an electric signal is provided, and a pulse-like signal corresponding to the rotation m of the DC motor 3 is output from the encoder 4. Incidentally, the encoder 4 is used when it is necessary to determine the position, for example, to detect the standby position when the chuck 1 performs the WI opening/closing operation of the chuck portion 1A, and is not necessarily necessary. The pulsed signal output from the encoder 4 is input to a waveform shaping circuit 5 for waveform shaping, and the signal output from the waveform shaping circuit 5 is inputted to an electronic control unit 6.

The slave control device 6 serves as the control center of the chuck drive device, and is composed of a logic circuit, a microcomputer, or the like. A setting device 7 is connected to the electronic control device 6 for setting the torque when the chuck 1 opens and closes the chuck portion 1A and grips the object M. This setting device! 7 is provided with a keyboard 7A and a display 7B for displaying setting data when the keyboard 7Δ is operated, and the torque data set with the keyboard 7A is transferred to the electronic control unit 6 and stored therein. In addition to the torque data, the setting device 7 sets the standby position of the chuck portion 1A as required.

The electronic control device 6 outputs a drive signal for driving the DC motor 3 to the drive control circuit 8 based on the torque set by the setting device 7. The drive control circuit 8 is connected to a drive circuit 9 whose main components are power transistors TR1, TR2, TR3 and TR4, and the power transistor T
A control signal for driving RI to T1 (4 is output to the base of each of the power transistors TR1 to TR4. The power transistor R1 forming the drive circuit 9
~ Among TR4, power transistors TRI and TR4 are driven when passing a drive current for forward rotation to the DC motor 3, while power transistors R2 and TR3 are driven when passing a drive current for reverse rotation to the DC motor 3. be done. In addition, a shunt 9A is inserted in the drive current supply circuit, and when a drive current is passed from the motor drive power source to the DC motor 3, a voltage drop corresponding to the magnitude of the drive current is generated across the shunt 9A. , this voltage drop is input to the current detection circuit 10 as a drive current detection signal.

The current detection circuit 10 inputting the drive current detection signal generated by the shunt 9A outputs a digital signal obtained by A/D converting the detection signal to the electronic control unit @6. Therefore, when a drive current for forward or reverse rotation is applied to the DC motor 3, the electronic control unit @6 can calculate the magnitude of the drive current, that is, the torque of the DC motor 3.

The chuck 1 is provided with a limit switch 11 for detecting the limit position in the opening direction of the chuck part 1A, and when the chuck part 1A is opened to the eye-opening position, the signal is transmitted to the electronic control device. ! ? Output to 6.

FIG. 2 shows a control timing chart of the electronic control device 6.

With the setting device 7 setting the torque for gripping the object M and the standby position for rapidly feeding and holding the chuck portion 1A to a predetermined position, the electronic control device 6: When inter-chuck control is started as shown in step 1, the electronic control device 6 sends the drive control circuit 8
A drive signal for high-speed feeding is output. As a result, the drive control circuit 8 outputs a transistor drive control signal corresponding to the drive signal to the transistors TRI and TR4, drives the transistors rR1 and TR4,
A normal rotation drive current for high-speed feeding is applied to the DC motor 3 from the motor drive power source. The chuck 1 is driven by the rotation of the DC motor 3 via the reducer 2, and the chuck part 1A is
When the operation starts, the limit switch 11 is turned off,
The electronic control device 6 controls the chuck section 1 as shown in step 2.
Recognize that A has left the eye-opening position.

In the next step 3, the electronic control device 6 inputs the signal from the encoder 4 via the waveform shaping circuit 5, recognizes the drive amount of the DC motor 3, calculates the drive position of the chuck part 1A, and calculates the drive position of the chuck part 1A. When it is determined that the chuck portion 1A has reached the standby position, the output of the drive signal for high-speed feeding is stopped, and the brake of the DC motor 3 is activated.

Next, the electronic control device 6 moves to torque control feeding shown in step 4 for the chuck section 1A to grip the object M.

As this torque control method, there is a method A in which torque control feed is performed at the timing shown in the charts of FIGS. 3, 4, and 5, and a method in which torque control feed is performed at the timing shown in the charts in FIGS. 6 and 7. B will be explained.

As shown in Fig. 3, torque control method A initially
The electronic control unit 6 outputs a drive signal equivalent to a low torque to the drive control circuit 8 at timing 3 so that the drive 3 is driven with a low torque that is enough to rotate without load. Next, it is determined whether the DC motor 3 has rotated by inputting the signal from the current detection circuit 10, and if it is determined that the DC motor 3 has rotated, the DC motor 3 is intermittently rotated at the low torque as shown in FIG. let

On the other hand, as shown in timing (3) in FIG. 3, if it is determined that the DC motor 3 does not rotate even if the drive signal corresponding to the low torque is output, the setting device The level of the drive signal is increased until it is determined that a drive current equivalent to the set torque has flowed, and the DC motor 3 is rotated as shown at timing ① to control the chuck part 1A to grip the object M with the set torque. .

When the electronic control unit 6 recognizes that the chuck part 1A has gripped the object M with the set torque, it moves to the loosening control to loosen the pressure gripping the object M, as shown at timing ■, and again at timings ■ to ■. Repeat the above control.

When this torque-controlled feeding is completed, the electronic m-device 6 outputs a high-speed return drive signal for reversing the DC motor 3 as shown in step 5, and controls the chuck portion 1A to open to the eye-opening position.

FIG. 5 shows the timing of torque generation output from the DC motor 3 using the torque control feed method A, and shows the torque generation timing outputted from the DC motor 3 by the torque control feeding method A, and the low torque LT and the set torque ST output at the timing This shows that the object is grasped with average force.

Next, based on FIGS. 6 and 7, torque control feeding method B
Explain.

At timing (3) in FIG. 6, the electronic control device 6 outputs a drive signal to the drive control circuit 8 so that the DC motor 3 is driven with a torque so low that it rotates without load. At this time, DCt
- When it is determined that the object M has rotated, a drive signal corresponding to the low torque is intermittently outputted, and the chuck portion 1A is driven to close at a predetermined period, so that the object M is gripped with an average torque.

On the other hand, when it is determined that the DC motor 3 does not rotate under the low torque drive, the electronic control unit 6 increases the output torque of the DC motor 3 in stages while inputting the signal from the current detection circuit 10. That is, at timing -1 in FIG. 6, a drive signal corresponding to a low torque below the set torque is output, and when it is determined that the drive current corresponding to the set torque has not been reached based on the signal from the current detection circuit 10, timing -1 is output. At timing -2, a drive signal corresponding to a torque one step larger than the torque at timing -1 is output. When it is determined that the drive current of the DC motor 3 has not reached the drive current corresponding to the set torque even by the output of the drive signal at timing ■-2, at timing ■-3, the drive current corresponding to a torque larger than the torque at timing ■-2 is Outputs a drive signal. As a result, when it is determined that the drive current corresponding to the set torque has been reached, the output of the drive signal is stopped, and the loosening control is performed to loosen the state in which the chuck part 1A grips the object M, and the above-mentioned timing control is further performed. By repeating this, the force applied to object M becomes constant. Note that the high-speed return control is the same as control method A.

FIG. 7 shows the timing of torque generation output from the DC motor 3 according to the torque control feed method B, and shows the low torque LT output at the timing ① and the torques T1 to T3 that are increased in stages. It is something that

(Effects of the Invention) As described above, according to the present invention, the output torque of the motor that drives the chuck part is intermittently adjusted without using a pressure sensor that is expensive and frequently damaged as in the past. Therefore, it is possible to provide a chuck driving device that can grip an object of any shape and any hardness with appropriate pressure without limiting the direction.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a chuck driving device according to an embodiment of the present invention, Fig. 2 is a control timing chart of the chuck driving device, and Figs. 3, 4, and 5 are torque control feeding charts of method A. 6 and 7 are torque control feed charts of method B. 1... Chuck 1A... Chuck part 1B... Chuck body part 3... DC motor 6... Electronic control device 7... Setting device 8... Drive control device 9... Drive circuit 9A...Shunt 10...Current detection circuit

Claims (1)

[Claims] a chuck for gripping an object of any shape and any hardness from any direction; a motor for driving the chuck portion;
drive current detection means for detecting a drive current applied to the motor and outputting a signal corresponding to the detected current; and torque setting means for setting the output torque of the motor when the chuck section grips the object. and a drive for intermittently outputting the required torque from the motor while inputting the signal output from the drive current detecting means and recognizing the output torque of the motor when the chuck section grips the object. A chuck drive device comprising: drive control means for outputting electric power to the motor.