CN113635304B - Robot-assisted laser real-time detection processing or etching integrated device and method - Google Patents

Abstract

Robot-assisted laser real-time detection processing or etching integrated device and method relate to the technical field of laser processing. The device comprises a laser unit, a mechanical arm unit, a cooling unit and a locating unit. The laser unit acquires position information of an object to be processed or etched, measures the thickness of a liquid layer sprayed on the surface of the object by the cooling unit, feeds back the thickness to the mechanical arm unit in real time, and automatically searches a laser focal plane; then the cooling unit receives the liquid layer thickness measured by the laser unit, and adjusts and controls the cooling medium parameters in real time to adapt to the output parameters of the laser unit; and then the locating unit recognizes the position information and the material attribute information of the object to be processed or etched, and regulates and controls the motion feeding of the mechanical arm unit and the switching light of the laser unit in real time. According to the invention, the motion track and cooling input of the mechanical arm are regulated and controlled in real time by a non-contact method, and the machining or the erosion is detected while the laser machining or the erosion is performed, so that the accuracy and the digitalization of the laser machining or the erosion are ensured, the unplanned tissue wound is reduced, and the robot-assisted laser material machining or the operation can be widely applied to the fields of robot-assisted laser material machining or the operation and the like.

Description

Robot-assisted laser real-time detection processing or erosion integrated device and method

technical field

The invention relates to the technical field of laser processing, in particular to a robot-assisted laser real-time detection processing or erosion integrated device and method.

Background technique

Compared with robot-assisted mechanical processing or ablation, robot-assisted laser real-time processing or ablation has unique advantages such as high precision, high degree of freedom, good repeatability and non-contact, and the scanning speed of laser can reach thousands of millimeters per second , and its work efficiency is much higher than traditional machining or erosion. However, it is difficult to measure and identify the processing depth and material properties inside the material during laser processing or ablation, resulting in the inability to accurately control and judge the laser action process, it is difficult to avoid unplanned tissue trauma, and there is often serious heat accumulation during the process. , Chip removal difficulties and other issues.

At present, the real-time position detection of manipulator-assisted laser processing reported at home and abroad is mainly solved by camera measurement devices (such as CCD cameras). The Chinese patent with the authorization number ZL201811229793.9 published on January 4, 2019 proposes an imaging positioning processing method based on a small coaxial laser processing system. However, this method is affected by the large field of view of the imaging system, and the field of view needs to be moved every time an area is processed. Not only is the operation complicated and the precision is low, but it is also difficult to ensure that the whole process of laser processing is completely on the laser focal plane, which directly affects laser processing. efficiency and effectiveness. In the Chinese patent with the publication number CN110090075A published on August 6, 2019, a femtosecond laser bone surgery method based on optical signal monitoring is provided to adjust the laser parameters by monitoring the laser excitation signal of the sputtered material. However, this method The position and material property information of the site to be operated cannot be known, and photoablation damage caused by exceeding the planned operation depth and ablation threshold due to improper removal feed trajectory cannot be avoided.

The interaction between the laser and the object is mainly based on the thermal ablation mechanism, and the liquid medium-assisted laser processing or ablation can reduce the thermal damage caused by the laser to the object. Chinese patents 201410331680.5 (published on November 5, 2014) and 201910909131.4 (published on December 13, 2019) respectively disclose devices and methods for liquid medium-assisted laser surgery and processing, but the introduction of an external liquid medium is mainly used for cooling , ignoring the interference effect of the liquid medium layer on the incident laser light. At present, domestic and foreign reports on liquid-assisted laser processing or ablation are limited to the adjustment of liquid medium with better cooling effect, but do not consider the coupling effect of laser and liquid medium to form a real-time monitoring and control of laser processing or ablation. A device or method for removing the thickness of the liquid layer, which overcomes the absorption of laser energy by the liquid or cavitation shielding to obtain the best laser processing/ablation effect. The defects of existing cooling devices and methods directly affect laser processing or ablation safety and performance.

In order to overcome the above problems, the present invention proposes a robot-assisted laser real-time detection and processing or erosion integrated device and method, the detection and control of which are implemented in a non-contact manner, to achieve real-time digital measurement and automatic control of laser processing or erosion, Break through the accuracy and efficiency bottlenecks of existing robot-assisted laser processing or ablation devices and methods.

Contents of the invention

The purpose of the present invention is to provide a robot-assisted laser real-time detection and processing or erosion integrated device and method to overcome the shortcomings of the prior art.

A robot-assisted laser real-time detection and processing or erosion integrated device and method, including a laser unit (1), a mechanical arm unit (2), a cooling unit (3) and a positioning unit (4), wherein:

The laser unit (1) includes a laser transmitter (1-1), a laser transmission optical path (1-2) and a laser receiver (1-3), and the tail of the laser transmitter (1-1) is provided with a laser receiver ( 1-3), the middle part of the laser transmitter (1-1) is coaxially matched with the laser receiver (1-3).

The mechanical arm unit (2) includes a mechanical arm (2-1) and a motion data transmission cable (2-2), and its motion end is respectively linked with the laser unit (1) through a connecting frame; Under power action, the laser unit (1) can complete the laser action on the part to be processed or ablated according to the planned path.

The cooling unit (3) includes a water sprayer (3-1) and a liquid flow regulator (3-2), and the liquid flow regulator (3-2) is connected with the laser transmitter (1-1), and the laser receiver ( 1-3) Measure the thickness of the liquid layer and flow parameters, and feed them back to the water flow controller (3-2), so as to regulate the flow and velocity of the water-cooling medium in real time.

The positioning unit (4) includes a detection light source (4-1), a signal processor (4-2) and a motion controller (4-3). On the surface of the object, the signal processor (4-2) receives and weights the reflected light signal of the object surface, and calculates the position signal and material property information of the material to be processed or etched according to the steady-state error in the received signal, and passes the signal through the motion data The transmission cable (2-2) is transmitted to the mechanical arm (2-1), and the motion feed of the end of the mechanical arm (2-1) and the switching light of the laser transmitter (1-1) are precisely regulated during the laser action process.

Further, the laser receiver (1-3) is fixedly installed at the laser transmitter (1-1) outlet, and the laser receiver (1-3) can be equipped with a divergence angle collimation shaper and a signal amplifier; the cooling unit ( 3) After spraying the cooling medium on the surface of the object to be processed or etched, the position information of the object to be processed or etched is obtained through the laser receiver (1-3) and fed back to the robotic arm unit (2) to realize the laser unit (1) The focal plane is automatically found.

Further, the laser transmitter (1-1) emits a laser beam with a pulse energy of I and a repetition frequency of τ and irradiates it on the surface of the object to be processed or ablated at a liquid medium flow rate of v, and passes through the laser receiver (1 -3) The resulting water layer thickness h satisfies the following formula: In the formula, ρ is the density of the liquid medium, and adjusting the flow parameter (Reynolds number Re), Re≤2300, can effectively suppress photocavitation, maximize the energy of the laser on the material, and improve the processing efficiency.

Further, the moving end of the mechanical arm unit (2) can realize the relative position adjustment of the laser unit (1) inside the object site, so that the laser unit (1) is always positioned at the laser emitter (1) during each laser processing process. -1) on the focal plane. The laser receiver (1-3) detects that the upper surface of the liquid medium is attached at a distance of H ₁ , the thickness of the water layer is h, and the signal processor (4-2) in the positioning unit (4) measures the depth of action H ₂ , the distance from the moving end of the mechanical arm unit (2) to the position to be processed or etched is automatically adjusted to H=H ₁ +hH ₂ by the motion controller (4-3), and the laser is focused under the flowing water layer The surface of an object to be processed or etched away.

Further, the signal processor (4-2) of the positioning unit (4) identifies material properties such as density and composition of the object to be processed or etched by decoupling optical signals. The material property remains unchanged, and the laser transmitter (1-1) emits light continuously; once the material property changes, the signal processor (4-2) feeds back a signal to the laser transmitter (1-1), and turns off the laser.

Based on the above-mentioned technical scheme, the present invention has the following beneficial effects compared with existing devices and methods:

(1) The present invention monitors the thickness of the liquid layer on the surface of the object in real time through the laser receiver (1-3) during processing, and feeds back to the liquid flow regulator (3-2) of the cooling unit (3) to adjust the flow rate and flow of the liquid medium, It can suppress photocavitation, promote the transmission of laser energy in the liquid medium layer, and improve the utilization rate of laser energy.

(2) In the present invention, the processed or ablated depth is detected in real time by the positioning unit (4) during laser processing, and is fed back to the mechanical arm unit (2) to measure and feed back the processed material. Carry out position calibration and precision compensation for the robotic arm; and avoid damage to unplanned tissue caused by the laser through the identification of the material properties of the tissue to be processed or ablated, and improve the accuracy of laser processing through the accurate identification of the properties of the material to be processed or ablated precision and safety.

Description of drawings

Fig. 1 is a schematic diagram of the composition of the robot-assisted laser real-time detection processing or erosion device of the present invention

Fig. 2 is a schematic flow chart of the robot-assisted laser real-time detection processing or erosion method of the present invention

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

The present invention provides a robot-assisted laser real-time detection processing or erosion integrated device and method, as shown in Figure 1, comprising: a laser unit (1), a mechanical arm unit (2), a cooling unit (3) and a positioning unit (4).

The laser unit (1) is driven above the target object through the movement of the mechanical arm unit (2), and the optical signal is transmitted to the laser receiver (1-3) through the laser transmission optical path (1-2) to obtain the object to be processed or etched The position information of the removed object is fed back to the mechanical arm unit (2) to realize the automatic search of the focal plane of the laser transmitter (1-1).

After the cooling unit (3) is turned on, the thickness of the liquid layer and the flow parameters are measured by the laser receiver (1-3), and accordingly the liquid parameters of the liquid flow controller (3-2) are adjusted from the liquid sprayer (3-1 ) output to match the laser parameters set by the laser transmitter (1-1), the thickness of the liquid layer satisfies Minimize the possibility of photocavitation occurring.

The positioning unit (4) irradiates the detection light emitted by the detection light source (4-1) on the surface of the object to be processed or etched, and the signal processor (4-2) receives and weights the reflected light signal of the object surface, and according to The steady-state error in the received signal calculates the position signal and material property information of the material to be processed or etched, and transmits the signal to the robotic arm unit (2) and laser unit (1) through the motion controller (4-3), precisely Regulate the movement feed of the end of the mechanical arm and the switch of the laser during the laser action.

Example 1:

The present invention is used for laser removal of isolated bone, and the specific implementation device is shown in FIG. 1 .

As shown in Fig. 1, the device includes: a laser unit (1), a mechanical arm unit (2), a cooling unit (3) and a positioning unit (4).

The laser unit (1) is driven above the target object through the movement of the mechanical arm unit (2), and the optical signal is transmitted to the laser receiver (1-3) through the laser transmission optical path (1-2) to obtain the image of the object to be processed. The position information is fed back to the mechanical arm unit (2) to realize the automatic search of the focal plane of the laser emitter (1-1). At this time, the laser emitter (1-1) is located 10 mm above the isolated pig tibia to be operated.

After the cooling unit (3) is turned on, the thickness of the liquid layer and the flow parameters are measured by the laser receiver (1-3), and accordingly the liquid parameters of the liquid flow controller (3-2) are adjusted from the liquid sprayer (3-1 ) output to match the laser parameters set by the laser transmitter (1-1), input the laser parameters pulse energy I=3.0J, repetition frequency τ=30Hz in the laser unit (1), and regulate the water flow regulator (3-2 ), water velocity v=4m/s.

Adjust liquid flow controller (3-2), make water layer thickness h=1mm<6.5mm, water layer thickness h=1mm<6.5mm, liquid layer thickness meets Flow parameter Re=1000.

The positioning unit (4) irradiates the detection light emitted by the detection light source (4-1) on the surface of the object to be processed, and the signal processor (4-2) receives and weights the reflected light signal of the object surface, and according to the received signal The steady-state error calculates the position signal and material property information of the material to be processed, and transmits the signal to the manipulator unit (2) and laser unit (1) through the motion controller (4-3) to precisely control the process of laser action The movement of the end of the robotic arm feeds and switches the laser until complete.

Example 2:

The present invention is used for laser drilling and cutting of composite metal sheets, and the specific implementation is shown in FIG. 2 .

Step 100, start the robot-assisted laser real-time detection and processing or erosion integrated device and method of the present invention.

Step 105, the laser unit (1) is driven above the composite plate by the movement of the mechanical arm unit (2), the cooling unit (3) is turned on, and the liquid layer thickness h=3mm is measured by the laser receiver (1-3).

Step 110, obtain the position information of the composite plate to be drilled and cut through the laser receiver (1-3) and feed it back to the mechanical arm unit (2) to realize the automatic search of the focal plane of the laser transmitter (1-1). At this time, the laser transmitter ( 1-1) Located 20mm above the composite metal sheet to be drilled and cut.

Step 115, input laser parameters pulse energy I=2.0J, repetition frequency τ=30Hz in the laser unit (1), adjust the water flow regulator (3-2), and the water flow velocity v=5m/s.

Step 120, compare the parameters, and detect whether the laser parameters are compatible with the thickness of the liquid layer, if not, go to step 125, and adjust the liquid flow controller (3-2); according to the parameter setting in step 115, the thickness of the water layer h= 1.6mm<3.6mm, liquid layer thickness meets Flow parameter Re=2150.

Step 130, the detection light source in the positioning unit (4) is irradiated on the composite metal sheet to be drilled and cut, and the interaction between the detection light source (4-1) and the surface of the material to be processed is recorded and processed by the signal processor (4-2) The resulting optical signal is processed by an analog-to-digital converter with a sampling rate of 330kHz. The signal is filtered and amplified for each laser pulse, sampling 128 data bits per pulse. The wavelet energy spectrum is used to measure the harmonic components in the optical signal, and the material property signal is collected.

Step 135, monitor in real time whether the material property of the composite metal sheet to be removed is the material to be processed. If not, go to step 140, terminate the work of the laser unit (1) and the mechanical arm unit (2); if so, continue to step 145, and the mechanical arm unit (2) drives the laser unit to work according to the preset track.

Step 150, the signal processor (4-2) identifies the boundary of the composite metal plate to be processed according to the change of the wavelet energy spectrum, and decouples the predictive model of the correlation between the optical signal and the depth.

Step 155, the laser receiver (1-3) detects that the upper surface distance H ₁ =22mm attached to the liquid layer, the thickness of the water layer h=1.6mm, the signal processor (4-2) in the positioning unit (4) The measured removed depth H ₂ =3.6mm, the distance from the moving end of the mechanical arm unit (2) to the position to be processed is automatically adjusted to H=H ₁ +hH ₂ =20mm by the motion controller (4-3), Focus the laser on the surface of the composite metal sheet to be removed under the flowing water layer.

Step 160, after each laser drilling and cutting is completed, the location-seeking unit (4) analyzes the properties such as material density through the reflected light signal. The position information fed back by the unit (2) is adjusted relative to the inside of the removal site, so that the laser unit (1) is always accurately focused on the focal plane of the laser emitter (1-1) during each laser drilling process.

Step 165, monitor in real time whether the material property of the composite metal sheet to be removed is the material to be processed. If not, go to step 170, terminate the work of the laser unit (1) and the mechanical arm unit (2); if yes, continue to step 160, the mechanical arm unit (2) drives the laser unit to work according to the preset trajectory, until the material to be processed is completely remove.

So far, those skilled in the art should appreciate that, although a number of exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, the disclosed embodiments of the present invention can still be used. Many other variations or modifications consistent with the principles of the invention are directly identified or derived from the content. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (2)

1. A method for detecting processing or etching integrated device in real time by using robot-assisted laser is characterized in that: the device comprises a laser unit, a mechanical arm unit, a cooling unit and a locating unit, wherein:

the laser unit comprises a laser emitter, a laser transmission light path and a laser receiver, wherein the laser receiver is arranged at the tail part of the laser emitter, and the middle part of the laser emitter is coaxially matched with the laser receiver;

the mechanical arm unit comprises a mechanical arm and a motion data transmission cable, and the motion end of the mechanical arm unit is connected with the laser unit in a linkage way; under the power action of the mechanical arm unit, the laser unit can complete the laser action of the part to be processed or etched according to the planned path;

the cooling unit comprises a liquid sprayer and a liquid flow regulator, the liquid flow regulator is connected with the laser transmitter, the thickness and the flow parameters of the liquid layer are measured through the laser receiver, and the liquid flow parameters are fed back to the liquid flow regulator to regulate and control the parameters of the water-cooling medium in real time;

the locating unit comprises a detection light source, a signal processor and a motion controller, wherein the detection light source emits detection light to irradiate the surface of an object to be processed or etched, the signal processor receives and weights reflected light signals of the surface of the object, calculates position information and material attribute information of the object to be processed or etched according to steady-state errors in the received signals, transmits the signals to the mechanical arm through a data transmission line, and regulates and controls motion feeding of the tail end of the mechanical arm and switching of a laser transmitter in the laser action process;

the method comprises the following steps:

(1) The laser unit moves to the upper part of the target object through the mechanical arm unit, and starts the cooling unit, and the laser receiver obtains the position information of the object to be processed or etched and removed and feeds the position information back to the mechanical arm unit to realize the automatic searching of the focal plane of the laser unit;

(2) The laser transmitter emits a laser beam with pulse energy of I and repetition frequency of tau and irradiates the surface of an object to be processed or etched with the flow velocity of liquid medium of v, and the liquid layer thickness h obtained by the laser receiver meets the following formula:wherein ρ is the density of the liquid medium; adjusting the liquid flow regulator to enable the liquid layer flow parameter, namely Reynolds number Re, to be less than or equal to 2300;

(3) The laser unit and the locating unit are driven to process the part to be processed or etched away along the planned path through the mechanical arm unit; after each laser action is finished, the motion end of the mechanical arm unit adjusts the relative position inside the laser action object according to the position information fed back by the locating unit, so that the laser unit is always and accurately focused on the focal plane of the laser transmitter in each laser action process; the laser receiver detects that the distance H between the upper surface of the liquid medium is attached ₁ The thickness of the water layer is H, and the processed or etched depth measured by the signal processor in the locating unit is H ₂ The distance from the moving end of the mechanical arm unit to the position to be laser acted on is automatically adjusted to be H=H through a motion controller ₁ +h-H ₂ Focusing laser on the surface of an object to be processed or etched away under the liquid layer;

(4) Identifying material properties of the object to be processed or etched by the locating unit, wherein the material properties at least comprise density and components of the object; when the material property is detected to be unchanged, completing laser processing or etching according to a planned path, and circulating until all laser processing or etching tasks are completed; when a change in a material property is detected, the processing or etching is stopped.

2. The method for real-time detection of machining or ablation by using a robot-assisted laser integrated device according to claim 1, wherein a laser receiver is fixedly installed at an outlet of a laser transmitter, and a divergence angle collimating shaper and an echo signal are arranged in the laser receiver; and after the cooling unit sprays cooling medium on the surface of the object to be processed or etched, the laser receiver obtains the position information of the object to be processed or etched and feeds the position information back to the mechanical arm unit to realize the automatic searching of the focal plane of the laser unit.