JPS62126409A - Self-traveling robot - Google Patents

Abstract

PURPOSE:To detect precisely the position of a self-traveling robot by forming absolute encoders for detecting the absolute rotational positions of traveling wheels corresponding to the position of a traveling car body on a traveling course. CONSTITUTION:The self-traveling robot consisting of the traveling car body 21 having traveling wheels 30, 31 to be rotated by driving devices 34, 35, a robot arm mechanism 22 arranged on the traveling car body and detectors 38, 39 for detecting the dislocation of the traveling car body 21 from the traveling course previously fixed on a traveling load is provided with the absolute encoders 45, 46 for detecting the absolute rotational positions of the traveling wheels 30, 31 corresponding to the position of the traveling car body 21 on the traveling course. Since the rotational quantity of the motor for driving the traveling wheels can be detected by the absolute encoders 45, 46, the position of the robot can be precisely detected by the rotational quantity of the driving motor and the traveling course of the traveling car body 21 in any position on the traveling course.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a self-propelled robot that can self-propel on a running road surface.

[Prior art and its problems]

In unmanned factories equipped with a plurality of machine tools, workbenches, etc., self-propelled robots are increasingly being used to efficiently deliver workpieces to machine tools, perform machining work on processing benches, etc. A conventional self-propelled robot includes a robot arm mechanism having a working attachment such as a robot hand or a tool at its tip, and a traveling vehicle body that supports the robot arm mechanism. The running vehicle body is equipped with a pair of running wheels that are individually driven by drive motors, and a sensor for detecting a guide wire arranged on the running road surface of the factory.The running vehicle body receives the detection signal of the sensor. By controlling the rotational speed of the drive motor based on this, it is possible to self-propel along the guide line while correcting deviation from the guide line.

Such self-propelled robots can move along a designated travel route according to operation command signals, but conventional self-propelled robots themselves have no way of knowing where the robot is on the travel route. Since the detection means for detecting the robot's position was placed at necessary locations such as the running road surface, a large number of detection means were required, and it was also difficult to detect the position of the self-propelled robot. There was a drawback that confirmation was rough.

[Means for Solving the Problems and Their Effects] As a means for solving the above problems, the present invention provides a traveling vehicle body having running wheels rotationally driven by a drive device, and a vehicle body provided on the traveling vehicle body. A self-propelled robot equipped with a robot arm mechanism and a deviation detector for detecting a deviation of the traveling vehicle body from a predetermined traveling path on a traveling road surface. A self-propelled robot is provided, characterized in that it is equipped with an absolute encoder that detects the absolute rotational position of the running wheel corresponding to the position.

According to the above means according to the present invention, the rotation amount of the motor that drives the running wheels can be detected by the absolute encoder, so that the self-propelled robot can This makes it possible to accurately know the position of a self-propelled robot no matter where it is on its travel route.

These and other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate embodiments of the invention.

〔Example〕

1 to 4 show one embodiment of the present invention. First, referring to FIGS. 1 and 2, the self-propelled robot 20 is equipped with a running vehicle body 21.
A robot arm mechanism 22 is installed above. The robot arm mechanism 22 has a base 23 fixed on the traveling vehicle body 21.
It is equipped with

A rotating body 24 is provided on the base 23 so as to be rotatable around an axis perpendicular to the installation surface of the base 23. An upper arm 25 is provided on the pivoting body 24 so as to be rotatable around an axis perpendicular to the pivoting axis of the pivoting body 24 . A forearm 26 is provided on the upper arm 25 so as to be rotatable around an axis parallel to the rotational axis of the upper arm 25. A robot hand 28 is attached to the tip of the forearm 26 via a wrist mechanism 27. Each part of the robot arm mechanism 22 operates according to operation commands from a robot controller 29 provided within the traveling vehicle body 21.

The running vehicle body 21 includes a pair of running wheels 30 and 31 on the left and right sides. The running wheels 30, 3'l each have a brake device 32.
．． 33 and AC servo motors 34 and 35. Casters 36 are installed before and after the running wheels 30 and 31, respectively.
is provided. A guide line 37 is buried in the running road surface along a predetermined running route, and the running vehicle body 21
Displacement detectors 38 and 39 for detecting deviation from the guide wire 37 are provided at the front and rear sides of the guide wire 37. Here, the shift detectors 38 and 39 are a pair of left and right magnetic sensors 38a that sense the strength of magnetism generated from the guide wire 37.

39a.

A vehicle body controller 40 is provided within the traveling vehicle body 21 to control the operation of the traveling vehicle body.

The vehicle body controller 40 controls the running wheels 30 according to the program.
．． Command signals such as normal rotation and reverse rotation of 31 and speed command signals such as high speed, medium speed, and low speed are given to servo amplifiers 41 and 42 connected to motors 34 and 35.

Further, when the traveling course of the traveling vehicle body 21 deviates from the guide line 37, the vehicle body controller 40 detects the deviation detector 38.3.
A speed correction signal necessary for course correction is provided to the servo amplifiers 41 and 42 in response to changes in the strength of magnetism sensed by the magnetic sensors 38a and 39a of 9.

Inside the traveling vehicle body 21, while the traveling vehicle body 21 is running, the traveling vehicle body 2 is
1 and a battery 43 that serves as a power source for the robot arm mechanism 22 are provided.

The motors 34, 35 that drive the running wheels 30, 31 are provided with absolute encoders 45, 46. Since the absolute encoders 45 and 46 have the same configuration, only one encoder 45 will be described below.

Referring to FIG. 3, the absolute encoder 45 includes a rotating shaft 46 connected to the output shaft of the motor 34, and the rotating shaft 46 has bearings 48, 49 against a casing 47 fixed to the housing of the motor 34. It is rotatably supported through.

Inside the casing 47, the rotary shaft 46 is provided with a two-pole resolver 5o as a first detector for detecting the absolute rotation angle within the range of one revolution.

Here, the two-pole resolver 5o has a pancake shape, that is, a disk shape with a small width in the axial direction. The two-pole resolver 5o has two primary windings 51 and 52, and the negative secondary winding 5.
1.52 and a stator core 53 that supports the
Stator core 53 is fixed to casing 47.

- The next windings 51 and 52 are supplied with carrier waves of sin ω and cos ωt from a carrier wave generation circuit 54 (see FIG. 4), respectively. Further, the resolver 5o includes a secondary winding 55 and a rotor core 56 that supports the secondary winding 55, and the rotor core 56 is fixed to the rotating shaft 46. Voltage signal (sin (ωt+β)) generated in the secondary winding 55
) is taken out of the casing 47 by the rotating transformer 57.

A two-pole resolver 58 is provided within the casing 47 as a second detector for determining the absolute rotational speed of the rotating shaft 46. The two-pole resolver 58 has two primary windings 59.
60, and a first core 61 for supporting the secondary winding 59°60, the first core 61 being a cylinder coaxially and rotatably supported on the rotating shaft 46 via a bearing 62. axis 6
It is fixed at 3. - The secondary windings 59,60 are each connected to the carrier wave generating circuit 54 via a rotating transformer 64,65, and sin ω is transmitted from the carrier wave generating circuit 54 to the primary winding 59,60 via the rotating transformer 64,65. and cosωt carrier waves are supplied.

Further, the two-pole resolver 58 includes a secondary winding 66 and a second core 67 for supporting the secondary winding 66.
The second core 67 is fixed to the rotating shaft 46. A voltage signal (sin (ωt+α)) generated in the secondary winding 62 is extracted to the outside of the casing 47 by a rotary transformer 68.

The cylindrical shaft 63 is connected to the rotating shaft 46 via a reduction gear 69. Here, the reducer 69 includes a gear 70 fixed to the rotating shaft 46 and a toothed portion 71 provided on the outer periphery of the cylindrical shaft 63.
An intermediate gear 72 that meshes with is rotatably supported via a bearing 73.

The tooth ratio between the gear 70 and the tooth portion 71 of the cylindrical shaft 63 is set to be slightly different from each other, so that the rotational speed ratio between the first core 61 and the second core 67 of the resolver 58 is only slightly different. different. For example, when the rotating shaft 46 rotates 100 times, the first core 61 rotates 101 times, and the second core 67 rotates 100 times.
It is set to rotate at 0.00 rotations.

Referring to FIG. 4, the voltage signal (sin (ωt+α)) output from the rotary transformer 68 and the carrier wave generation circuit 5
The carrier wave output (sinωt) from 4 is input to a phase discrimination circuit 74, which is known per se. The phase discrimination circuit 74 determines the phase difference α between the two input signals and outputs it to the arithmetic processing circuit 75. On the other hand, the voltage signal (sin (ωt+β)) output from the rotary transformer 57 and the carrier wave output (sin ωt) from the carrier wave generation circuit 54 are input to another phase discrimination circuit 76 which is itself well known. The phase discrimination circuit 76 determines the phase difference β between the two input signals and outputs it to the arithmetic processing circuit 75.

The arithmetic processing circuit 75 determines the total rotation amount X of the rotating shaft 46 from the relationship between the rotational speed ratio Z f /Z s between the primary winding 59 and the secondary winding 66 of the resolver 58 and the phase difference α. This calculation method itself is described in Japanese Patent Application Laid-Open No. 59-2 by the present applicant.
It is well known from Publication No. 26819.

The total amount of rotation X of the rotating shaft 46 is the number of rotations of the rotating shaft 46
(n is an integer value), and the rotation angle within one rotation of the rotation shaft 46 is x, (x is a decimal value). Since X = 2π (n + x), from the calculated value of the total rotation amount 46 rotation speed n can be determined.

As mentioned above, the decimal value X represents the rotation angle within the rotation of the rotation axis 4601601, but since the decimal value X may include errors due to hacklash of the gear mechanism and detection accuracy,
Here, the phase difference β corresponding to the rotation angle within one rotation of the rotating shaft 46 is accurately determined by the resolver 50 and the phase discrimination circuit 76. That is, the arithmetic processing circuit 75 calculates how many rotations and what position the rotating shaft 46 is at from the integer value n of X and the phase difference β, and outputs it to the vehicle body controller 40. Since this calculated value corresponds to the position of the traveling vehicle body 21 on the traveling route, the absolute position of the traveling vehicle body 21 on the traveling route can be known from this calculated value.

When the traveling vehicle body 21 approaches a predetermined stop position, for example, a stop position near the station unit 77, the vehicle body controller 40 decelerates and stops the servo motors 34, 35 and operates the brake devices 32, 33 to stop the traveling wheels. 30 and 31 are decelerated and stopped. At the stop position, the vehicle body controller 40 sends a signal to the centering device 78 provided on the traveling vehicle body 21 to engage the centering device 78 with a positioning protrusion 79 provided on the traveling road surface. As a result, the traveling vehicle body 21 is positioned and fixed at a predetermined stop position.

When the centering operation of the traveling vehicle body 21 is completed at the stop position near the station unit 77, the vehicle body controller 40 sends a signal to the movable connector 80 provided on the traveling vehicle body 21, and the movable connector 80 is connected to the movable connector 80 provided on the station unit 77. The fixed connector 81 is connected to the fixed connector 81.

By connecting both connectors 80 and 81, the signal cables are mutually connected between the traveling vehicle body 21 and the station unit 77. Further, charging of the battery 43 mounted on the traveling vehicle body 21, power supply to the traveling vehicle body 21 and the robot arm mechanism 22, etc. are performed through the connectors 80 and 81.

Although the illustrated embodiments have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the invention as set forth in the claims. For example, the first detector for detecting the absolute rotation angle within one rotation of the rotating shaft 46 may be an optical absolute encoder using a fixed and rotating code plate and an optical sensor. Further, the reducer 69 incorporated in the second detector for detecting the absolute rotational speed of the rotating shaft 46 may be any other type of reducer as long as it has a high reduction ratio, such as a so-called harmonic drive reducer. It may be a machine. Further, the robot arm mechanism 22 on the traveling vehicle body 21 may have any type of arm movement. Further, as a method for detecting the deviation of the traveling vehicle body 21 with respect to the traveling route, for example, a guidance method using a barcode tape and an image sensor may be used.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the amount of rotation of the motor that drives the running wheels can be detected by the absolute encoder, so that the amount of rotation of the drive motor and the traveling path of the traveling vehicle body can be used to detect the amount of rotation of the motor that drives the running wheels. This makes it possible to provide a self-propelled robot that can accurately know the position of the self-propelled robot wherever it is on the travel route.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the configuration of a traveling vehicle body and a control system of a self-propelled robot according to an embodiment of the present invention; FIG. 2 is a schematic perspective view of the self-propelled robot shown in FIG. 1; FIG. 3 is a sectional view of essential parts of the absolute encoder, and FIG. 4 is a block diagram of the electric circuit of the absolute encoder.

Claims (1)

[Claims] 1. A traveling vehicle body having running wheels rotationally driven by a drive device, a robot arm mechanism provided on the traveling vehicle body, and detecting a deviation of the traveling vehicle body from a predetermined traveling path on a traveling road surface. The self-propelled robot is equipped with an absolute encoder that detects the absolute rotational position of the running wheel corresponding to the position of the running vehicle body on the running path. Running robot.