JPS63207582A - Robot with arm for reinforcing - 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 robot equipped with a reinforcing arm to compensate for a decrease in rigidity due to a reduction in the weight of the robot arm.

(Prior Art) Conventional robot arms are thick and heavy in order to have rigidity so as not to bend under load. However, improvements in the robot's payload to dead weight ratio and
When considering workability in narrow spaces, it is essential to reduce the weight and size of the robot arm. Therefore, for example, in the robot arm disclosed in Japanese Patent Application Laid-Open No. 125786/1986, a sub-arm that does not have a load bearing is installed in parallel with the main arm, and changes in relative position with the sub-arm due to deflection of the main arm are detected. This detected amount is input as a correction signal to the control signal of the main arm drive device to position the main arm tip.

Although in principle it is possible to accurately position the tip of the main arm without increasing the rigidity of the main arm in this way, in reality the amount of arm deformation increases as the arm rigidity decreases. As a result, correction becomes difficult, which inevitably causes problems such as a decrease in positional accuracy and vibrations.

(Objective of the Invention) Therefore, an object of the present invention is to provide a robot arm that is lightweight and can maintain a required rigidity without writhing.

(Structure of the Invention) The robot according to the present invention includes a reinforcing arm arranged in parallel with the main arm in order to suppress deflection of the main arm, and a holding member that holds the reinforcing arm substantially parallel to the main arm. However, this holding member is provided on the outer periphery of the main arm so as to be rotatable coaxially with respect to the main arm. Furthermore, there is a deflection direction detecting means for detecting the deflection direction of the main arm, and a holding member is rotated in accordance with the deflection direction of the main arm detected by this detection means, and the reinforcing arm is rotated so as to detect the deflection direction of the main arm. 6. (Effects of the Invention) According to the present invention, the reinforcing arm immediately moves the main arm in response to the direction of deflection of the main arm. Since the robot arm is configured to move to a position where the deflection of the robot arm can be suppressed, a lightweight and highly rigid robot arm can be obtained.

(Example) An example of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall view of the robot, and FIG. 2 shows its arm. 1 is a main arm, 2 is an arm hand, and 3 is a reinforcing arm that also serves as an arm hand drive shaft. This reinforcing arm 3 is provided on the outer periphery of the main arm 1 at a predetermined interval in the axial direction thereof, is held by glasses-shaped holding members 4a and 4b, and is provided almost parallel to the main arm 1. As shown in FIG. 3, the holding members 4a and 4b are
The reinforcing arm 3 is rotatably provided coaxially on the outer periphery of the main arm 1 via a conical bearing 6 . And these holding members 4a, 4
A gear 7a is provided on the outer periphery of each gear 7a over a predetermined angular range.
, 7b are formed, and a motor 8 is connected to these gears 7a, 7b.
Gears 10a and 10b provided on a direction control drive shaft 9 that is rotationally driven by are engaged with each other, and the holding members 4a and 4b are configured to be rotated coaxially with the main arm 1 by a motor 8, These holding members 4a, 4b
The direction of the reinforcing arm 3 with respect to the main arm 1 is controlled as the reinforcing arm 3 rotates. The direction control drive shaft 9 has bearings 11a and llb fixed to the main arm 1.
is supported by.

On the other hand, gears 12a and 12b are attached to the reinforcing arm 3 which also serves as the arm hand drive shaft, and gears 12a and 12b are attached to both ends of the reinforcing arm 3. It meshes with gear 13. Further, the gear 12b in the base end example meshes with an idler gear 15 rotatably provided on the outer periphery of the main arm 1 via a bearing 14, as shown in FIG. A gear 17 attached to an arm hand drive shaft 16 meshes with this idler gear 15. Therefore, the rotation of the arm hand drive shaft 16 is from gear 17 to idler gear 15.
→ Gear 12b → Reinforcement arm 3 → Gear 12a - Gear 13
The information is transmitted to the arm hand 2 via.

Furthermore, a plurality of strain sensors 18 such as strain gauges are attached to the outer peripheral surface of the main arm 1 , and the output signals of these strain sensors 18 are amplified by an amplifier 19 and then sent to a motor control circuit 20 .

The motor control circuit 20 analyzes the signals sent from the plurality of strain sensors 18 and detects the direction in which the load is applied to the main arm 1. Then, the motor 8 is driven so that the direction in which the load is applied matches the direction of the reinforcing arm 3 seen from the main arm 1, and the holding members 12a, 12b are
is rotated to move the reinforcing arm 3 along the outer periphery of the main arm 1. As a result, the rectangle formed by the main arm 1, the reinforcing arm 3, and the holding member 12a or 12b becomes parallel to the load direction, increasing the moment of inertia of the area, improving the arm strength, and suppressing the deflection of the main arm 1. . Note that even if the reinforcing arm 3 moves to any position on the outer circumference of the main arm 1, the relative coordinates between the gear 17 and the gear 13 do not change, so there is no need to correct the position of the arm hand drive motor. do not have.

Next, FIG. 5 is a block diagram showing a control circuit for the direction control motor 8, and FIG. 6 is a flowchart showing the flow of the control.

In step S1 in FIG. 6, the direction of the principal stress applied to the main arm 1 is determined based on the output of the strain sensor 18. In the next step S2, the current position of the reinforcing arm 3 is referred to from the output of the encoder 21 indicating the rotational position of the motor 8, and in the next step S3, the moving direction and moving angle of the reinforcing arm 3 are determined, It is stored in the storage device 22.

In the next step S4, the moving direction and moving angle of the reinforcing arm stored in the storage device 22 are read out and the motor 8 is driven. The rotational position of the motor 8 is encoded by an encoder 21. In the next step S5, the current principal stress direction is determined from the output of the strain sensor 18, and in step S6 it is determined whether or not this principal stress direction coincides with the position of the reinforcing arm 3. If YES, end the control,
If NO, the process returns to step S1 and the above-described flow is repeated.

The above is an explanation of the configuration and operation of an example of a robot having a reinforcing arm according to the present invention. According to the wooden embodiment, the arm hand drive shaft can effectively function as a reinforcing arm, and it is lightweight and A highly rigid robot arm can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an overall view of a robot implementing the present invention, Fig. 2 is a perspective view of the robot arm, and Figs. 3 and 4 are taken along the mm line and -TV line of Fig. 2, respectively. 5 is a block diagram of the control circuit, and FIG. 6 is a flowchart. 1-Main arm 2-Arm hand 3-Reinforcement arm 4a, 4b-Holding members 7a, 7b, 10a,
10b, 12a, 12b, 13, I 7--Gear 8-Motor 9 One-way control drive shaft 15-Idler gear 16-Arm hand drive shaft

Claims (1)

[Scope of Claims] A reinforcing arm installed in parallel with the main arm in order to suppress the deflection of the main arm of the robot; a holding member that holds the reinforcing arm substantially parallel to the main arm; a deflection direction detection means for detecting a deflection direction of the main arm; and a deflection direction detection means for detecting the deflection direction of the main arm detected by the detection means. drive means for rotating the holding member in accordance with the direction and moving the reinforcing arm along the outer periphery of the main arm to a position where the reinforcing arm can suppress deflection of the main arm; A robot with a reinforcing arm.