Multiple lens-based smart mechanical arm and positioning and assembly method thereof

Patent metadata

Field	Value
Publication number	US-10899014-B2
Application number	US-201615781856-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Jan 27, 2016
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A multiple lens-based smart mechanical arm, wherein it comprises a multi joint multi-functional mechanical arm, a CCD camera for collecting PCB board images to be assembled, a bio-contact device, and a computer; the CCD camera is mounted on the multi joint multi-functional mechanical arm, the bio-contact device is mounted on the fingertip of the multi joint multi-functional mechanical arm, and the CCD camera, and the bio-contact device and the multi joint multi-functional mechanical arm are connected to the computer. The invention adds a biological tactile device on the basis of the binocular positioning to accurately locate the assembly target area and improve the accuracy of the assembly of the irregular parts. The conversion relationship between the pressure and electric output of the sensitive material in the bio-contact device and the mathematical model of pressure and position is applied. The present invention realizes high-precision and real-time assembly of irregular parts and improves the production efficiency of the electronic assembly industry.

First claim

What claimed is:

1. A multiple lens-based smart mechanical arm, comprising a multi-joint multi-functional mechanical arm, CCD cameras for collecting PCB board images to be assembled, a bio-contact device, and a computer; the CCD cameras are mounted on the multi-joint multi-functional mechanical arm, the bio-contact device is mounted on a fingertip of the multi-joint multi-functional mechanical arm, and the CCD cameras, and the bio-contact device and the multi-joint multi-functional mechanical arm are connected to the computer.

2. The multiple lens-based smart mechanical arm according to claim 1 wherein two CCD cameras are provided and are are installed on a left side and a right side of a forearm of the multi-joint multi-functional mechanical arm respectively.

3. The multiple lens-based smart mechanical arm according to claim 1 wherein the bio-contact device comprises a chip made of a sensitive material and a signal measurement circuit for measuring deformation of the chip and outputting an electrical signal; the chip is covered on the fingertip of the mechanical arm and connected with the signal measurement circuit; the signal measurement circuit is connected with the computer and provided inside the multi-joint multi-function mechanical arm.

4. The multiple lens-based smart mechanical arm according to claim 3 wherein shape of the chip is finger-sleeve type.

5. The multiple lens-based smart mechanical arm according to claim 3 wherein the sensitive material is made of conductive rubber.

6. The multiple lens-based smart mechanical arm according to claim 2 wherein the two CCD cameras have the same model and parameters; coordinate systems of the two camera coplanar and the coordinate axes are in parallel.

7. A positioning and assembly method of a smart mechanical arm comprising,
(1) transporting PCB to assemble on to the front of a mechanical arm, capturing two images of the PCB to assemble by two CCD cameras comprising a left camera and a right camera, the image being a left and a right image respectively;
(2) matching the two image with a PCB template pre-inputted in a computer by the computer, and determining a target area for assembling irregular parts in the two images;
(3) using a binocular positioning algorithm to measure the distance between the target area and a fingertip of the mechanical arm, and controlling the mechanical arm to move to the target area for preliminary positioning by the computer;
(4) contacting a bio-contact device of the fingertip of the mechanical arm with the target area, wherein a deformation electrical signal generated by a chip on the bio-contact device is output to the computer through a signal measuring circuit, and the computer adjusts a position of the mechanical arm to realize accurate positioning.

8. The positioning and assembly method according to claim 7 wherein, step (2) specifically comprises: filtering and denoising the two images captured by the two CCD cameras of the PCB to assemble on, extracting an edge portion of the PCB by an edge detection operator removing a background portion, enhancing the two images and improving a contrast of same by a piecewise linear transform enhancement method, and determining the target area for assembly by a grayscale-based template matching method.

9. The positioning and assembly method according to claim 7 wherein step (3) specifically comprises:
(3.1) solving the cameras' internal parameter matrix and external parameter matrix by the Zhang Zhengyou calibration algorithm; performing a binocular stereoscopic calibration to determine a relative position relationship of the left and right cameras, the relative position relationship of the left and right cameras including a rotation matrix R and a translation vector T;
(3.2) matching the two images pixel by pixel by using gray-scale cross-correlation matching method based on template matching;
(3.3) determining the distance between the target area and the fingertip of the mechanical arm by the binocular positioning algorithm:

l
=

Bf
x

x
=

x
left

-

x
right

wherein B is the distance between the projection centers of the two camera: when a target point A is imaged on an A1 point on a left CCD image plane and an A2 point on a right CCD image plane when passing through a binocular ranging system consisting of the left and right cameras with parallel axes, x left and x right are the positions of A1 and A2 on the left and right image planes respectively; f is a camera focal length, and x is the difference in the positions of A1 and A2 and is non-zero.

10. The positioning and assembly method according to claim 7 , wherein step (4) specifically comprises: after preliminary the positioning, contacting the bio-contact device on the fingertip of the mechanical arm with the PCB to assemble on, wherein a pressure on a sensitive material of the bio-contact device changes due to deformation, thereby changing the output electrical signals; and adjusting the position of the mechanical arm according to the output electrical signals and a mathematical relationship between pressure and position so as to irregular parts in an accurate position.

Assignees

• Univ South China Tech

Inventors

• Du Juan
• Tan Jiansheng
• Feng Ying

Classifications

• H04N23/54

  Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils · CPC title

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title

• H05K13/0812 Primary

  the monitoring devices being integrated in the mounting machine, e.g. for monitoring components, leads, component placement · CPC title

• H05K13/0404

  Pick-and-place heads or apparatus, e.g. with jaws · CPC title

• B25J13/084

  Tactile sensors (in general G01L5/16, G01L5/22) · CPC title