Non-contact multi-robot cooperation coordinate system conversion device and methodTechnical Field
The invention relates to the technical field of industrial robot measurement, in particular to a non-contact multi-robot cooperation coordinate system conversion device and method.
Background
With the rapid development of robotics, industrial robots are widely used in various industries. With the continuous development of high-end manufacturing industry, the requirements on absolute positioning accuracy of industrial robots are higher and higher, and the requirements are especially applied to the fields of laser welding, laser cutting, aerospace and the like. With the complexity of production tasks and the flexibility of production processes, existing robots operating with independent stations have failed to meet the ever-changing manufacturing requirements. Compared to a single robot, the multi-robot system has the following advantages: stronger job capability, more flexible system architecture, and stronger collaboration capability, etc. Multi-robot collaboration is capable of accomplishing tasks that a single robot cannot or cannot do, such as complex assembly operations, handling heavy objects, collaboratively welding complex workpieces, collaboratively manipulating flexible objects, and the like.
The calibration problem of the base coordinate system is a key technology in the multi-robot cooperation system, and as the base coordinate system of the robot cannot be directly measured, external detection is needed to be carried out through equipment such as a visual sensor or a laser tracker to realize the conversion of the base coordinate system of the robot, and the equipment has high price and complex field arrangement. Document "Base frame calibration for coordinated industrial robots, robotics and Autonomous Systems,2012" proposes to implement the transformation of the coordinate system by point constraints of the tool TCP; however, the method depends on the operation experience of a person, and the conversion precision is also influenced by the calibration precision of the TCP; and such physical constraints may cause end collisions of the robot due to operator mishandling.
Disclosure of Invention
The invention aims to provide a non-contact multi-robot cooperation coordinate system conversion device and a non-contact multi-robot cooperation coordinate system conversion method, which are used for realizing high-precision conversion of a multi-robot cooperation coordinate system.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
The utility model provides a non-contact multi-robot cooperation coordinate system conversion equipment, includes industrial robot one, industrial robot two, position detection device and distance detection device are fixed mounting respectively at industrial robot two and industrial robot one's end, distance detection device contains a plurality of laser rangefinder sensor and a fixed plate, and a plurality of laser rangefinder sensor is around the center evenly distributed of fixed plate at fixed plate outside end edge, fixed plate fixed mounting is at industrial robot one's end, position detection device contains a plurality of two-dimensional PSD sensor and an adapter plate, and a plurality of two-dimensional PSD sensor is around the center evenly distributed of adapter plate in adapter plate outside end department, adapter plate fixed mounting is at industrial robot two's end, and a plurality of laser rangefinder sensor and a plurality of two-dimensional PSD sensor one-to-one setting.
Further, the laser ranging sensor is uniformly arranged six around the center of the fixed plate, and the two-dimensional PSD sensor is uniformly arranged six around the center of the adapter plate.
Further, the end of the first industrial robot is provided with a first flange plate, the fixing plate is fixedly arranged on the first flange plate, the end of the second industrial robot is provided with a second flange plate, and the adapter plate is fixedly arranged on the second flange plate.
Further, the first industrial robot, the second industrial robot, the laser ranging sensor and the two-dimensional PSD sensor are respectively and electrically connected with a power supply, the signal output ends of the laser ranging sensor and the two-dimensional PSD sensor are respectively and electrically connected with the signal input end of a control host, and the output ends of the control host are respectively and electrically connected with the first industrial robot and the second industrial robot.
A conversion method of a non-contact multi-robot cooperation coordinate system conversion device comprises the following steps:
S1: firstly, defining the following steps that the coordinates of a plurality of laser ranging sensors under a local coordinate system T1 of a distance detection device are expressed as (xuj,yuj, 0), wherein u is used for identifying the distance detection device, and j is the serial number of the laser ranging sensors; the conversion relation from the detection coordinate system of each two-dimensional PSD sensor to the local coordinate system T2 of the position detection device is Hi;
S2: controlling the second industrial robot provided with the position detection device to be opposite to the direction of the industrial robot provided with the distance detection device, and adjusting the relative positions of the first industrial robot and the second industrial robot to ensure that the emitted light of the laser ranging sensor can be received by the two-dimensional PSD sensor with the corresponding serial number;
S3: the distance measurement value of the laser ranging sensor is Li, the laser ranging sensor emits light to form point-shaped light spots on the two-dimensional PSD sensor, and the coordinate system of each point-shaped light spot under the coordinate system of the two-dimensional PSD sensor is (xi,yi, 0), wherein i is the serial number of the two-dimensional PSD sensor; according to the conversion matrix Hi from the detection coordinate system of the two-dimensional PSD sensor to the local coordinate system of the position detection device, the coordinate can be converted into the coordinate under the local coordinate system of the position detection device, which is marked as (xdi,ydi, 0), wherein d is used for marking as the position detection device;
S4: calculating a position vector P= [ x, y, z ] of the device according to the data, wherein the attitude vector is Q= [ alpha, beta, gamma ], and establishing the following model according to the data:
Wherein,
The solving process is as follows:
s41: order the
F＝[f1......fn]T，
S42: according to the pose range, an initial pose Xk is given, the allowable error is epsilon, k=0,
S43: solving a vector function F (Xk) and a Jacobian matrix # -F (Xk),
S44：Xk+1＝Xk-▽F(Xk)-1F(Xk)，
S45: if |Xk+1-Xk | < epsilon, terminating to obtain the current pose data of the pose device; otherwise, k=k+1, S43 is performed;
the pose data obtained in the step are the local coordinate system of the position detection device relative to the local coordinate system of the distance detection device; from the above pose data, a transformation matrix can be calculated:
S5: defining the conversion relation of the flange plate of the first industrial robot under the base coordinate system F1 as H1, and the conversion relation of the distance detection device under the flange plate coordinate system of the second industrial robot as HTCP1; the conversion relation of the flange plate of the industrial robot II under the base coordinate system F2 is H2, and the conversion relation of the position detection device under the flange plate coordinate system of the industrial robot I is HTCP2; then the following constraint equation can be established:
F1H1HTCP1＝F2H2HTCP2H
The base coordinate system conversion matrix of the first industrial robot and the second industrial robot is:
F1＝F2H2HTCP2H(H1HTCP1)-1。
Further, the values of j and 6,i are 1 to 6,j, and i are integers and correspond to each other one by one.
Compared with the prior art, the invention has the beneficial effects that:
1. When two robots are controlled to move, the distance detection device and the position detection device are opposite, the pose conversion relation of the two devices is accurately calculated through the distance measurement data of a plurality of distance sensors and the position data of a plurality of two-dimensional PSD sensors, and high-precision calibration of a multi-robot cooperation coordinate system can be realized.
2. The detection of multiple robots is realized in a non-contact mode, and the measurement range of the two-dimensional PSD sensor is large and can reach +/-20 mm, so that the requirement on operators is reduced.
3. The whole device is simple and convenient to install and can be arranged at will on the industrial site.
Drawings
FIG. 1 is a schematic installation diagram of a conversion device of the present invention;
FIG. 2 is a schematic diagram of the conversion device of the present invention;
FIG. 3 is a schematic view of the mounting of the posture device of the present invention;
FIG. 4 is a schematic diagram of a position detecting apparatus according to the present invention;
fig. 5 is a schematic diagram of the measuring principle of the conversion device of the present invention.
The reference numerals in the drawings are: the device comprises a first industrial robot, a second industrial robot, a 3-position detection device, a 4-distance detection device, a 5-adapter plate, a 6-two-dimensional PSD sensor, a 7-fixed plate and an 8-laser ranging sensor.
Detailed Description
The invention will now be described in further detail with reference to the drawings and examples.
Referring to fig. 1-5, a non-contact type multi-robot cooperation coordinate system conversion device comprises an industrial robot 1, an industrial robot 2, a position detection device 3 and a distance detection device 4, wherein the position detection device 3 and the distance detection device 4 are respectively and fixedly installed at the tail ends of the industrial robot 2 and the industrial robot 1, the distance detection device 4 comprises a plurality of laser ranging sensors 8 and a fixing plate 7, the plurality of laser ranging sensors 8 are uniformly distributed around the center of the fixing plate 7 at the edge of the outer side end of the fixing plate 7, the fixing plate 7 is fixedly installed at the tail end of the industrial robot 1, the position detection device 3 comprises a plurality of two-dimensional PSD sensors 6 and a pinboard 5, the plurality of two-dimensional PSD sensors 6 are uniformly distributed around the center of the pinboard 5 at the outer side end of the pinboard 5, and the pinboard 5 is fixedly installed at the tail end of the industrial robot 2, and the plurality of laser ranging sensors 8 are arranged in one-to-one correspondence with the plurality of two-dimensional PSD sensors 6.
Six laser ranging sensors 8 are uniformly arranged around the center of the fixed plate 7, and six two-dimensional PSD sensors 6 are uniformly arranged around the center of the adapter plate 5.
The end of the industrial robot I1 is provided with a flange plate I, the fixing plate 7 is fixedly arranged on the flange plate I, the end of the industrial robot II 2 is provided with a flange plate II, and the adapter plate 5 is fixedly arranged on the flange plate II.
The industrial robot I, the industrial robot II 2, the laser ranging sensor 8 and the two-dimensional PSD sensor 6 are respectively and electrically connected with a power supply, the signal output ends of the laser ranging sensor 8 and the two-dimensional PSD sensor 6 are respectively and electrically connected with the signal input end of a control host, and the output ends of the control host are respectively and electrically connected with the industrial robot I and the industrial robot II 2.
A conversion method of a non-contact multi-robot cooperation coordinate system conversion device comprises the following steps:
S1: first, the coordinates of the plurality of laser ranging sensors 8 in the local coordinate system T1 of the distance detecting device 4 are denoted as (xuj,yuj, 0), where u is a serial number of the laser ranging sensor 8 and is used as the distance detecting device 4,j; the conversion relation from the detection coordinate system of each two-dimensional PSD sensor 6 to the local coordinate system T2 of the position detection device 3 is Hi;
s2: the two industrial robots 2 of the installation position detection device 3 are controlled to be opposite to the first industrial robot 1 of the installation distance detection device 4, the relative positions of the first industrial robot 1 and the second industrial robot 2 are regulated, and the emitted light of the laser ranging sensor 8 is ensured to be received by the two-dimensional PSD sensor 6 with the corresponding serial number; the measuring range of the two-dimensional PSD sensor 6 is larger and can reach +/-20 mm, so that the technical requirement on operators is not high;
S3: the distance measurement value of the laser ranging sensor 8 is Li, the laser ranging sensor 8 emits light to form point-shaped light spots on the two-dimensional PSD sensor 6, and the coordinate system of each point-shaped light spot under the coordinate system of the two-dimensional PSD sensor 6 is (xi,yi, 0), wherein i is the serial number of the two-dimensional PSD sensor 6; from the conversion matrix Hi of the detection coordinate system of the two-dimensional PSD sensor 6 to the local coordinate system of the position detection device 3, the coordinates can be converted into coordinates under the local coordinate system of the position detection device 3, denoted (xdi,ydi, 0), where d is used for identification as the position detection device 3;
S4: calculating a position vector P= [ x, y, z ] of the device according to the data, and establishing the following model according to the data, wherein the attitude vector is Q= [ alpha, beta, gamma ]:
Wherein,
Because the model is a nonlinear equation, an analytic solution cannot be obtained well, the target pose parameters can be solved by adopting methods such as Newton iteration method, and the solving process is as follows:
s41: order the
F＝[f1......fn]T，
S42: according to the pose range, an initial pose Xk is given, the allowable error is epsilon, k=0,
S43: solving a vector function F (Xk) and a Jacobian matrix # -F (Xk),
S44：Xk+1＝Xk-▽F(Xk)-1F(Xk)，
S45: if |Xk+1-Xk | < epsilon, terminating to obtain the current pose data of the pose device; otherwise, k=k+1, S43 is performed;
The pose data obtained in this step is the local coordinate system of the position detection device 3 relative to the local coordinate system of the distance detection device 4; from the above pose data, a transformation matrix can be calculated:
S5: defining the conversion relation of the flange plate of the first industrial robot 1 under the base coordinate system F1 as H1, and the conversion relation of the distance detection device 4 under the flange plate coordinate system of the second industrial robot 2 as HTCP1; the conversion relation of the flange plate of the industrial robot II 2 under the base coordinate system F2 is H2, and the conversion relation of the position detection device 3 under the flange plate coordinate system of the industrial robot I1 is HTCP2; then the following constraint equation can be established:
F1H1HTCP1＝F2H2HTCP2H
the base coordinate system conversion matrix of the industrial robot 1 and the industrial robot 2 is:
F1＝F2H2HTCP2H(H1HTCP1)-1。
The values of j and i are 1-6,i, 1-6,j and integer, and the values of j and 6,j are in one-to-one correspondence.
The whole device utilizes the laser ranging sensor 8 and the two-dimensional PSD sensor 6 to construct the multi-robot cooperation coordinate system calibration device, is convenient to install, can be arranged at any place in industry, is not influenced by external environment light, realizes the multi-robot cooperation coordinate system calibration in a non-contact mode, has larger control redundancy, and reduces the requirement on operators.
The present invention is not limited to the preferred embodiments, and any simple modification, equivalent replacement, and improvement made to the above embodiments by those skilled in the art without departing from the technical scope of the present invention, will fall within the scope of the present invention.