CN112621746A - PID control method with dead zone and mechanical arm visual servo grabbing system - Google Patents

PID control method with dead zone and mechanical arm visual servo grabbing system Download PDF

Info

Publication number
CN112621746A
CN112621746A CN202011400173.4A CN202011400173A CN112621746A CN 112621746 A CN112621746 A CN 112621746A CN 202011400173 A CN202011400173 A CN 202011400173A CN 112621746 A CN112621746 A CN 112621746A
Authority
CN
China
Prior art keywords
mechanical arm
end effector
velocity
pose
control method
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202011400173.4A
Other languages
Chinese (zh)
Inventor
陈祥
刘佩林
应忍冬
钱久超
文飞
张澜涛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yantai Information Technology Research Institute Shanghai Jiaotong University
Shanghai Jiaotong University
Original Assignee
Yantai Information Technology Research Institute Shanghai Jiaotong University
Shanghai Jiaotong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yantai Information Technology Research Institute Shanghai Jiaotong University, Shanghai Jiaotong University filed Critical Yantai Information Technology Research Institute Shanghai Jiaotong University
Priority to CN202011400173.4A priority Critical patent/CN112621746A/en
Publication of CN112621746A publication Critical patent/CN112621746A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00—Programme-controlled manipulators
    • B25J9/16—Programme controls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00—Programme-controlled manipulators
    • B25J9/16—Programme controls
    • B25J9/1694—Programme controls characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
    • B25J9/1697—Vision controlled systems

Abstract

The invention discloses a PID control method with a dead zone, which is used for controlling a mechanical arm visual servo grabbing system and comprises the following steps: calculating the deviation of the target pose of the object and the pose of the end effector; processing the deviation by using a dead zone module, then taking the deviation as the input of a PID controller, and taking the output of the PID controller as the Cartesian space velocity of an end effector; converting the Cartesian space velocity into a joint space velocity; and filtering the joint space velocity by using a second-order Butterworth filter, and then transmitting the joint space velocity to a mechanical arm velocity controller to realize the real-time control of the pose of the mechanical arm. The invention also provides a mechanical arm vision servo grabbing system using the method. The control method provided by the invention can solve the problem of 'shaking' caused by frequent adjustment of the mechanical arm control system when the end effector of the mechanical arm approaches the target pose, and is beneficial to realizing the stable control of the pose of the mechanical arm.

Description

PID control method with dead zone and mechanical arm visual servo grabbing system
Technical Field
The invention relates to the field of intelligent control, in particular to a PID control method with a dead zone and a mechanical arm visual servo grabbing system using the method.
Background
Along with the rapid development of artificial intelligence and the improvement of the manufacturing level of the robot and the vision sensor, the vision perception is combined with the robot technology, and the automation and intelligence level of the robot is greatly improved. As a robot with high flexibility, the mechanical arm has a huge application prospect in the aspect of completing intelligent grabbing of objects by combining a visual perception technology, can be widely applied to industries such as automobile manufacturing, medical service, warehouse logistics and the like, and becomes a hot point for studying by scholars at home and abroad. In order to realize successful grabbing of the target material, the pose of the mechanical arm needs to be adjusted according to the pose of the target material fed back by a vision system, and the closed-loop control of the mechanical arm realized by combining the vision perception and the mechanical arm control technology is called vision servo control.
In the currently published mechanical arm visual servo control, CN 110116410 a discloses a mechanical arm target guidance system based on visual servo, which mainly solves the problems of shielding and separating from the visual field in the target imaging in the visual servo; CN 108058171A discloses a mechanical arm vision servo system based on position and closed-loop control, which mainly relates to a hardware realization method of the system, but does not relate to a control algorithm; CN 110919654 a discloses application of visual servo in the field of automatic docking of robot arms, and the content does not relate to a robot arm control algorithm; CN 107414825 a discloses a motion planning system for an industrial robot to smoothly grasp a moving object, which mainly relates to the contents of path obstacle avoidance. The prior art does not relate to the precise, stable and real-time control of the mechanical arm visual servo.
Accurate arrival of the pose of the target material is the key for the mechanical arm to successfully grab the object, so a controller with reasonable design is required to realize closed-loop control of the mechanical arm based on visual feedback. However, in a closed-loop control system, when a mechanical arm approaches a target pose, frequent adjustment occurs, so that the mechanical arm shakes, and a mechanical arm driving system and a hardware structure are damaged. In addition, in a complex grabbing scene, for example, materials in the warehouse logistics industry are generally randomly placed and the pose may change, and the mechanical arm is required to track the pose of the target material in real time. In conclusion, the realization of accurate, stable and real-time control of the mechanical arm is the problem to be solved in the process of grabbing an object by the mechanical arm vision.
Therefore, the technical personnel in the field are dedicated to develop a PID control method with a dead zone and a mechanical arm vision servo grabbing system using the method, on the basis of realizing accurate control of the pose of the mechanical arm, the problem of 'shaking' of the end effector of the mechanical arm when the end effector approaches a target pose can be solved through a dead zone module, and stable control of the pose of the mechanical arm is favorably realized.
Disclosure of Invention
In order to achieve the above object, the present invention provides a PID control method with a dead zone, wherein the control method is used for controlling a mechanical arm visual servo gripping system, and the control method comprises:
step 1: calculating the deviation of the target pose of the object and the pose of an end effector of the mechanical arm vision servo grabbing system;
step 2: processing the deviation by using a dead zone module;
and step 3: taking the deviation obtained in the step (2) as the input of a PID controller, and taking the output of the PID controller as the Cartesian space velocity of the end effector;
and 4, step 4: converting the Cartesian space velocity obtained in the step 3 into a joint space velocity;
and 5: filtering the joint space velocity obtained in the step 4 by using a second-order Butterworth filter;
step 6: and (5) issuing the result obtained in the step (5) to a mechanical arm speed controller of the mechanical arm visual servo grabbing system to realize the real-time control of the pose of the mechanical arm.
In some embodiments, optionally, the control method further includes step 7: repeating the steps 1 to 6.
In some embodiments, optionally, the cartesian spatial velocity of the end effector is related to the deviation obtained in step 2 as follows:
Figure BDA0002812279050000021
wherein, Ve(t) said Cartesian spatial velocity, e (t) said deviation obtained in step 2, Kp、KiAnd KdProportional coefficient, integral coefficient and differential coefficient of the PID controller are respectively.
In some embodiments, optionally, the step 3 comprises:
representing the Cartesian spatial velocity as Ve(t)＝[vx(t),vy(t),vz(t),wx(t),wy(t),wz(t),]TWherein v isx(t)，vy(t) and vz(t) represents linear velocity, ω, of the end effector in the x, y and z directions, respectivelyx(t)，ωy(t) and ωz(t) represents angular velocity of the end effector in x, y and z axis directions, respectively;
said deviation from said v obtained in said step 2x(t)，vy(t) and vz(t) is as follows:
Figure BDA0002812279050000022
wherein e isx(t)、ey(t) and ez(t) deviations in the x, y and z-axis directions of the position of the object and the position of the end effector, respectively, wherein ex(t)＝xg(t)-xe(t)，ey(t)＝yg(t)-ye(t)，ez(t)＝zg(t)-ze(t)，xg(t)、yg(t) and zg(t) denotes the position of the object in the x, y and z-axis directions, respectively, xe(t)、ye(t) and ze(t) represents the position of the end effector in the x, y and z axis directions, respectively;
the angular velocity is expressed by quaternion, and the relationship between the angular velocity and the quaternion is as follows:
Figure BDA0002812279050000031
the differential expression using the result of equation (3) obtained through the step 2 as the quaternion is as follows:
Figure BDA0002812279050000032
wherein e isq0(t)、eq1(t)、eq2(t) and eq3(t) q for target attitude, respectivelyg0(t)、qg1(t)、qg2(t) and qg3Q of (t) component and actual attitudee0(t)、qe1(t)、qe2(t) and qe3(t) deviation between components.
In some embodiments, optionally, the step 4 comprises the following steps:
deriving a positive kinematic model of the mechanical arm based on a D-H method;
determining a linear velocity Jacobian matrix and an angular velocity Jacobian matrix of the end effector to further obtain a Jacobian matrix of the mechanical arm;
and obtaining the transformation from the Cartesian space velocity to the joint space velocity according to the Jacobian matrix of the mechanical arm.
In some embodiments, optionally, deriving the positive kinematic model of the robotic arm based on the D-H method comprises:
obtaining a transformation matrix from the coordinate system { i-1} to the coordinate system { i } according to the D-H method, wherein the homogeneous coordinate expression of the transformation matrix is as follows:
Figure BDA0002812279050000033
wherein c represents a cos function and s represents a sin function;
the three-dimensional position and posture of the end effector are relative to a transformation matrix T of a mechanical arm base coordinate system {0}0 6Expressed as:
T0 6＝T0 1T1 2T2 3T3 4T4 5T5 6(6)
the homogeneous coordinate transformation matrix T of the end effector relative to the mechanical arm base coordinate system {0}0 6The expression of (a) is as follows:
Figure BDA0002812279050000034
wherein (p)x,py,pz) Representing the position of the end effector in cartesian space,
Figure BDA0002812279050000041
a rotation matrix for the end effector pose.
In some embodiments, optionally, the linear velocity jacobian is calculated as:
for joint space vector (theta)1,θ2,θ3,θ4,θ5,θ6) Differential derivation can be performed to obtain an expression of the linear velocity jacobian matrix, as follows:
Figure BDA0002812279050000042
wherein, JvRepresenting the linear velocity jacobian matrix;
and obtaining the expression of each element in the formula (8) according to the formula (7).
In some embodiments, optionally, the expression of the angular velocity jacobian matrix is as follows:
Figure BDA0002812279050000043
wherein, JwRepresenting the jacobian matrix of angular velocities,
Figure BDA0002812279050000044
representing a transformation of the base coordinate system to the i-th joint coordinate system,
Figure BDA0002812279050000045
for said transformation matrix T0i, the vector corresponding to the first three rows of the third column.
The invention also provides a mechanical arm visual servo control system which comprises a main control computer, a mechanical arm control cabinet, a six-joint mechanical arm, an end effector and an RGBD camera;
the main control computer is connected with the RGBD camera; the mechanical arm control cabinet is connected with the main control computer, the six-joint mechanical arm is connected with the mechanical arm control cabinet, the end effector is arranged at the tail end of the six-joint mechanical arm, and the end effector is connected with the mechanical arm control cabinet;
wherein the RGBD camera is configured to be capable of acquiring an image of a target object and transmitting the image to the master control computer; the main control computer is configured to be capable of executing the control method, converting an execution result into a speed signal of a mechanical arm joint space, and sending the speed signal to the mechanical arm control cabinet; the mechanical arm control cabinet is configured to control the six-joint mechanical arm according to the speed signal, enable the end effector to reach a target pose, then control the end effector to grab the object, and feed back an actual pose of the end effector to the master control computer.
In some embodiments, optionally, the end effector is a suction device.
The PID control method with the dead zone and the mechanical arm visual servo grabbing system using the method have the following technical effects:
the mechanical arm vision servo grabbing system based on the PID controller with the dead zone mainly comprises a main control computer, a mechanical arm control cabinet, a six-joint mechanical arm, a sucker device, an RGBD (red, green and blue) camera and the like, and can be applied to sorting of materials in the storage and logistics industry. Compared with the existing mechanical arm control technology, the mechanical arm vision servo grabbing system with the dead zone PID controller provided by the invention can remove the problem of 'shaking' caused by frequent adjustment of the mechanical arm control system when the mechanical arm end effector approaches the target pose through the dead zone module on the basis of realizing accurate control of the pose of the mechanical arm, and is favorable for realizing stable control of the pose of the mechanical arm. Meanwhile, in order to realize the real-time adjustment of the pose of the mechanical arm, a mechanical arm speed control mode is adopted, and the output value of the PID controller with the dead zone is used as the speed of the mechanical arm end effector, so that the target material can be tracked and grabbed in real time.
The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.
Drawings
FIG. 1 is a control block diagram of the PID control method with dead band of the present invention;
FIG. 2 is a diagram of the hardware components of the robot vision servo-gripping system of the present invention.
Detailed Description
The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.
In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views.
As shown in fig. 1, the PID control method with dead zone provided by the present invention includes the following steps:
step 1: calculating the object pose P of the objectgAnd 5, obtaining the pose P of the end effector through the positive kinematic modeleThe deviation e (t) therebetween, expressed as:
e(t)＝Pg-Pe(1)
step 2: in the invention, in order to avoid the mechanical arm shaking caused by the frequent adjustment of a mechanical arm vision servo system when the end effector reaches a target pose, a dead zone module is added before the deviation e (t) obtained in the step 1 is input into a PID controller, and the expression is as follows:
Figure BDA0002812279050000051
processing the deviation e (t) in a dead zone module, and if the deviation is out of the dead zone range, carrying out PID adjustment on the pose of the end effector; otherwise, the pose of the end effector does not need to be adjusted. Wherein e is0The dead zone value needs to be determined according to the regulation performance and the control precision requirement of the PID controller with the dead zone.
And step 3: the deviation e (t) obtained in the step 2 is used as the input of a PID controller, and the output of the PID controller is used as the Cartesian space velocity V of the end effectore(t) of (d). Obtaining V according to PID controller expressione(t) is as in formula (3), wherein Kp、KiAnd KdProportional coefficient, integral coefficient and differential coefficient of the PID controller.
Figure BDA0002812279050000052
The end effector of a robotic arm has six degrees of freedom including three positions and three attitude angles, so the end effector velocity may be expressed as Ve(t)＝[vx(t),vy(t),vz(t),wx(t),wy(t),wz(t),]T. The cartesian spatial velocities of the end effector described in the present invention are based on the mechanical arm base coordinate system, and the linear velocities and angular velocities are analyzed separately.
(1) Taking the calculated result of the PID controller with the dead zone as the speed of the end effector of the mechanical arm, wherein the linear speeds in the directions of the x axis, the y axis and the z axis are vx (t), vy (t) and vz (t), and the expression is as follows:
Figure BDA0002812279050000061
wherein ex(t)、ey(t) and ez(t) deviations in the x, y and z-axis directions of the target position from the position of the end effector of the robot arm, i.e., ex(t)＝xg(t)-xe(t)，ey(t)＝yg(t)-ye(t)，ez(t)＝zg(t)-ze(t)。
(2) The attitude of the end effector of the mechanical arm has various expression modes, including a rotation matrix, a rotation vector, an Euler angle and a quaternion. The quaternion is not only compact but also has no singularity, so the method analyzes the angular velocity of the end effector on the basis of the quaternion. The quaternion expression is
Figure BDA0002812279050000062
The angular velocity has the following relationship with the derivative of the quaternion:
Figure BDA0002812279050000063
taking the result obtained by the quaternion deviation through the PID algorithm with the dead zone as a differential expression of the quaternion, namely:
Figure BDA0002812279050000064
wherein e isq0(t)、eq1(t)、eq2(t) and eq3(t) q for target attitude, respectivelyg0(t)、qg1(t)、qg2(t) and qg3Q of (t) component and actual attitudee0(t)、qe1(t)、qe2(t) and qe3(t) deviation between components.
And 4, step 4: the mechanical arm Cartesian space velocity cannot be directly issued to a mechanical arm velocity controller, the mechanical arm Cartesian space velocity is required to be converted into joint space velocity, an instantaneous kinematics model of the mechanical arm is involved, and the derivation process is as follows:
(1) and deriving a positive kinematics model of the mechanical arm based on a D-H method, and deriving an instantaneous kinematics model on the basis to realize the conversion from the Cartesian space velocity to the joint space velocity. For the convenience of expression, respectively simplifying the cos function and the sin function into c and s, and obtaining a transformation matrix from a coordinate system { i-1} to a coordinate system { i } according to a D-H parameter method, wherein the homogeneous coordinate expression is as follows:
Figure BDA0002812279050000071
the three-dimensional position and pose of the end effector may be understood as a transformation matrix, T, relative to the base coordinate system {0} of the robot arm0 6. The transformation of the end effector into a base coordinate system can be derived from the relationship between adjacent coordinate systems:
T0 6＝T0 1T1 2T2 3T3 4T4 5T5 6(8)
in determining joint position thetaiOn the premise of (1), the pose of the end effector under a mechanical arm base coordinate system {0} can be determined. The homogeneous coordinate transformation matrix of the end effector of the robot arm relative to the base coordinate system {0} has an expression in the form of equation (9):
Figure BDA0002812279050000072
wherein (p)x,py,pz) Representing the position of the end effector in cartesian space,
Figure BDA0002812279050000073
is a rotation matrix of the end effector pose. The expression of each element in formula (9) can be determined according to formula (7) and formula (8) and under the condition of determining each joint angle.
(2) In visual servo controller design, the calculation of the deadband PID algorithm is taken as the end effector velocity. In order to realize the control of the mechanical arm, the Cartesian space velocity needs to be converted into the joint space velocity. The Jacobian matrix J establishes a joint space velocity q to a Cartesian space velocity
Figure BDA0002812279050000074
The expression is as follows:
Figure BDA0002812279050000075
the expression of joint space velocity obtained by pseudo-inverse transformation of the Jacobian matrix J is
Figure BDA0002812279050000076
It is therefore necessary to determine the expressions of the jacobian matrix J first. For the convenience of derivation, the jacobian matrix of the mechanical arm is split into two parts, i.e., J ═ Jv,Jw]TWherein JvAnd JwThe end effector linear and angular velocity jacobian matrices are shown separately. First to JvDerivation is carried out in positive kinematics model of the arm (p)x,py,pz) Representing end effector position, versus joint space vector (θ)1,θ2,θ3,θ4,θ5,θ6) Differential derivation can be performed to obtain JvIs shown in formula (11), and the expression of each element in formula (11) can be obtained from formula (9).
Figure BDA0002812279050000077
How many degrees the mechanical arm rotary joint rotates around its own axis of rotation, and accordingly, how many degrees the end effector rotates around this axis. The angular velocity in the three-dimensional space is a vector pointing to a rotating shaft, each rotating joint of the mechanical arm rotates around a Z axis of the mechanical arm, and if the rotating speed of the joint under a certain rotating shaft is w, the unit angular velocity vector of the end effector by taking the rotating shaft as a reference is [0,0,1 ]]. To obtain a jacobian matrix angular velocity portion JwAnd if the reference system of each rotary joint needs to be converted into a base coordinate system, the expression of the angular velocity part J of the Jacobian matrix can be obtained as follows:
Figure BDA0002812279050000081
wherein the content of the first and second substances,
Figure BDA0002812279050000082
the transformation from the base coordinate system to the ith joint coordinate system is expressed, and the derivation process of the positive kinematics model of the mechanical arm is known
Figure BDA0002812279050000083
For transforming the matrix T0 iThe vector corresponding to the first three rows of the third column, thus obtaining JwThe expression of (1).
The Jacobian matrix J of the mechanical arm can be obtained by combining the formula (11) and the formula (12), and the Jacobian matrix J of the mechanical arm can be obtained according to the formula
Figure BDA0002812279050000084
The transformation from the Cartesian space velocity to the joint space velocity can be obtained.
And 5: due to the existence of the interference information, the joint space velocity obtained in the step 4 is fluctuated, and in order to realize smooth and stable control of the mechanical arm, a second-order Butterworth filter with good comprehensive performance is used for filtering the joint space velocity obtained in the step 4.
Step 6: and (5) issuing the joint space speed obtained in the step (5) to a mechanical arm speed controller to realize the real-time control of the pose of the mechanical arm.
And 7: and (5) repeating the steps 1-6 to realize accurate, stable and real-time adjustment of the pose of the end effector of the mechanical arm relative to the pose of the target.
Based on the PID control method with the dead zone, the invention provides a mechanical arm visual servo grabbing system, as shown in FIG. 2. The invention provides a mechanical arm visual servo grabbing system based on a PID (proportion integration differentiation) controller with a dead zone. The main control computer is connected with the RGBD camera; the mechanical arm control cabinet is connected with the main control computer, the six-joint mechanical arm is connected with the mechanical arm control cabinet, and the end effector is arranged at the tail end of the six-joint mechanical arm and used for grabbing target materials. The end effector is also connected with the mechanical arm control cabinet. The RGBD camera acquires a two-dimensional image and a depth image of a target material and transmits the two-dimensional image and the depth image to the main control computer in real time; target material identification and pose calculation are carried out through a main control computer, and the pose result is converted into a target pose taking a mechanical arm base coordinate system as reference; and the main control computer executes the calculation of the PID control method with the dead zone and converts the calculation result into a speed signal of the joint space of the mechanical arm. The speed control signal is sent to the mechanical arm control cabinet to control the six-joint mechanical arm in real time, meanwhile, the mechanical arm control cabinet outputs a grabbing signal to the sucker device after the mechanical arm end effector reaches a target pose, and in addition, the mechanical arm control cabinet feeds back the actual pose of the six-joint mechanical arm to the main control computer to realize closed-loop control of the pose of the mechanical arm. In some embodiments, the end effector can select a suction cup device.
Compared with the existing mechanical arm control technology, the mechanical arm vision servo grabbing system with the dead zone PID controller provided by the invention can remove the problem of 'shaking' caused by frequent adjustment of the mechanical arm control system when the mechanical arm end effector approaches the target pose through the dead zone module on the basis of realizing accurate control of the pose of the mechanical arm, and is favorable for realizing stable control of the pose of the mechanical arm. Meanwhile, in order to realize the real-time adjustment of the pose of the mechanical arm, a mechanical arm speed control mode is adopted, and the output value of the PID controller with the dead zone is used as the speed of the mechanical arm end effector, so that the target material can be tracked and grabbed in real time.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (10)

1. A PID control method with dead zones is characterized in that the control method is used for controlling a mechanical arm visual servo grabbing system, and the control method comprises the following steps:
step 1: calculating the deviation of the target pose of the object and the pose of an end effector of the mechanical arm vision servo grabbing system;
step 2: processing the deviation by using a dead zone module;
and step 3: taking the deviation obtained in the step (2) as the input of a PID controller, and taking the output of the PID controller as the Cartesian space velocity of the end effector;
and 4, step 4: converting the Cartesian space velocity obtained in the step 3 into a joint space velocity;
and 5: filtering the joint space velocity obtained in the step 4 by using a second-order Butterworth filter;
step 6: and (5) issuing the result obtained in the step (5) to a mechanical arm speed controller of the mechanical arm visual servo grabbing system to realize the real-time control of the pose of the mechanical arm.
2. The PID control method with a dead zone according to claim 1, characterized in that the control method further comprises step 7: repeating the steps 1 to 6.
3. The dead band PID control method according to claim 1, wherein the cartesian spatial velocity of the end effector is related to the deviation obtained in the step 2 as follows:
Figure FDA0002812279040000011
wherein, Ve(t) said Cartesian spatial velocity, e (t) said deviation obtained in step 2, Kp、KiAnd KdProportional coefficient, integral coefficient and differential coefficient of the PID controller are respectively.
4. The PID control method with a dead zone according to claim 3, wherein the step 3 comprises:
representing the Cartesian spatial velocity as Ve(t)＝[vx(t),vy(t),vz(t),wx(t),wy(t),wz(t),]TWherein v isx(t)，vy(t) and vz(t) represents linear velocity, ω, of the end effector in the x, y and z directions, respectivelyx(t)，ωy(t) and ωz(t) represents angular velocity of the end effector in x, y and z axis directions, respectively;
said deviation from said v obtained in said step 2x(t)，vy(t) and vz(t) is as follows:
Figure FDA0002812279040000012
wherein e isx(t)、ey(t) and ez(t) deviations in the x, y and z-axis directions of the position of the object and the position of the end effector, respectively, wherein ex(t)＝xg(t)-xe(t)，ey(t)＝yg(t)-ye(t)，ez(t)＝zg(t)-ze(t)，xg(t)、yg(t) and zg(t) denotes the position of the object in the x, y and z-axis directions, respectively, xe(t)、ye(t) and ze(t) represents the position of the end effector in the x, y and z axis directions, respectively;
the angular velocity is expressed by quaternion, and the relationship between the angular velocity and the quaternion is as follows:
Figure FDA0002812279040000021
the differential expression using the result of equation (3) obtained through the step 2 as the quaternion is as follows:
Figure FDA0002812279040000022
wherein e isq0(t)、eq1(t)、eq2(t) and eq3(t) q for target attitude, respectivelyg0(t)、qg1(t)、qg2(t) and qg3Q of (t) component and actual attitudee0(t)、qe1(t)、qe2(t) and qe3(t) deviation between components.
5. The PID control method with a dead zone according to claim 4, wherein the step 4 comprises the steps of:
deriving a positive kinematic model of the mechanical arm based on a D-H method;
determining a linear velocity Jacobian matrix and an angular velocity Jacobian matrix of the end effector to further obtain a Jacobian matrix of the mechanical arm;
and obtaining the transformation from the Cartesian space velocity to the joint space velocity according to the Jacobian matrix of the mechanical arm.
6. The dead-zone PID control method according to claim 5, wherein the process of deriving the positive kinematic model of the robot arm based on the D-H method is as follows:
obtaining a transformation matrix from the coordinate system { i-1} to the coordinate system { i } according to the D-H method, wherein the homogeneous coordinate expression of the transformation matrix is as follows:
Figure FDA0002812279040000023
wherein c represents a cos function and s represents a sin function;
the three-dimensional position and posture of the end effector are relative to a transformation matrix T of a mechanical arm base coordinate system {0}0 6Expressed as:
Figure FDA0002812279040000024
the homogeneous coordinate transformation matrix T of the end effector relative to the mechanical arm base coordinate system {0}0 6The expression of (a) is as follows:
Figure FDA0002812279040000025
wherein (p)x,py,pz) Representing the position of the end effector in cartesian space,
Figure FDA0002812279040000031
a rotation matrix for the end effector pose.
7. The dead-band PID control method according to claim 6, wherein the linear velocity jacobian is calculated as: for joint space vector (theta)1,θ2,θ3,θ4,θ5,θ6) To carry outDifferential derivation can yield an expression of the linear velocity jacobian matrix, as follows:
Figure FDA0002812279040000032
wherein, JvRepresenting the linear velocity jacobian matrix;
and obtaining the expression of each element in the formula (8) according to the formula (7).
8. The PID control method with dead band according to claim 6, wherein the expression of the angular velocity jacobian matrix is as follows:
Figure FDA0002812279040000033
wherein, JwRepresenting the jacobian matrix of angular velocities,
Figure FDA0002812279040000034
representing a transformation of the base coordinate system to the i-th joint coordinate system,
Figure FDA0002812279040000035
for the transformation matrix
Figure FDA0002812279040000036
The vector corresponding to the first three rows of the third column.
9. A mechanical arm visual servo control system is characterized by comprising a main control computer, a mechanical arm control cabinet, a six-joint mechanical arm, an end effector and an RGBD (red, green and blue) camera;
the main control computer is connected with the RGBD camera; the mechanical arm control cabinet is connected with the main control computer, the six-joint mechanical arm is connected with the mechanical arm control cabinet, the end effector is arranged at the tail end of the six-joint mechanical arm, and the end effector is connected with the mechanical arm control cabinet;
wherein the RGBD camera is configured to be capable of acquiring an image of a target object and transmitting the image to the master control computer; the master control computer is configured to be able to execute the control method according to any one of claims 1 to 8, convert the execution result into a velocity signal of a robot joint space, and send the velocity signal to the robot arm control cabinet; the mechanical arm control cabinet is configured to control the six-joint mechanical arm according to the speed signal, enable the end effector to reach a target pose, then control the end effector to grab the object, and feed back an actual pose of the end effector to the master control computer.
10. The robotic arm vision servo control system of claim 9 wherein the end effector is a suction device.
CN202011400173.4A 2020-12-02 2020-12-02 PID control method with dead zone and mechanical arm visual servo grabbing system Pending CN112621746A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011400173.4A CN112621746A (en) 2020-12-02 2020-12-02 PID control method with dead zone and mechanical arm visual servo grabbing system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011400173.4A CN112621746A (en) 2020-12-02 2020-12-02 PID control method with dead zone and mechanical arm visual servo grabbing system

Publications (1)

Publication Number Publication Date
CN112621746A true CN112621746A (en) 2021-04-09

Family

ID=75308324

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011400173.4A Pending CN112621746A (en) 2020-12-02 2020-12-02 PID control method with dead zone and mechanical arm visual servo grabbing system

Country Status (1)

Country Link
CN (1) CN112621746A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113117943A (en) * 2021-04-30 2021-07-16 泉州华中科技大学智能制造研究院 Robot spraying method and device for shoe material spraying
CN113814985A (en) * 2021-10-29 2021-12-21 遨博（北京）智能科技有限公司 Robot control method, control cabinet and system
CN114161399A (en) * 2021-12-20 2022-03-11 大连理工大学 Six-degree-of-freedom mechanical arm Cartesian space moving target real-time tracking control method
CN116512237A (en) * 2022-11-28 2023-08-01 广东建石科技有限公司 Industrial robot vision servo method, device, electronic equipment and storage medium

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60189412A (en) * 1984-03-09 1985-09-26 Star Seiki:Kk Automatic removing device of injection molded article
CN105676880A (en) * 2016-01-13 2016-06-15 零度智控（北京）智能科技有限公司 Control method and system of holder camera device
CN106502162A (en) * 2016-11-30 2017-03-15 北京理工大学 A kind of automatic Control Theory Experiment teaching system based on portable mechanical arm
CN107856029A (en) * 2017-11-29 2018-03-30 长春工业大学 A kind of electro-hydraulic combination drive industrial machinery arm configuration and control system
CN108121215A (en) * 2017-09-12 2018-06-05 山东科技大学 Process control loops method of evaluating performance and device based on full loop reconstruct emulation
CN108372130A (en) * 2018-03-20 2018-08-07 华南理工大学 A kind of target locating, sorting system and its implementation based on FPGA image procossings
CN109782764A (en) * 2019-01-21 2019-05-21 湖北汽车工业学院 A kind of unmanned logistics distribution system of intelligent solar, control method and dispensing vehicle

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60189412A (en) * 1984-03-09 1985-09-26 Star Seiki:Kk Automatic removing device of injection molded article
CN105676880A (en) * 2016-01-13 2016-06-15 零度智控（北京）智能科技有限公司 Control method and system of holder camera device
CN106502162A (en) * 2016-11-30 2017-03-15 北京理工大学 A kind of automatic Control Theory Experiment teaching system based on portable mechanical arm
CN108121215A (en) * 2017-09-12 2018-06-05 山东科技大学 Process control loops method of evaluating performance and device based on full loop reconstruct emulation
CN107856029A (en) * 2017-11-29 2018-03-30 长春工业大学 A kind of electro-hydraulic combination drive industrial machinery arm configuration and control system
CN108372130A (en) * 2018-03-20 2018-08-07 华南理工大学 A kind of target locating, sorting system and its implementation based on FPGA image procossings
CN109782764A (en) * 2019-01-21 2019-05-21 湖北汽车工业学院 A kind of unmanned logistics distribution system of intelligent solar, control method and dispensing vehicle

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
张成宇: "基于视觉伺服的机器人控制研究", 《中国硕士学位论文全文数据库（电子期刊）信息科技辑》 *
朱 枫等: "跟踪微分器在陀螺信号去噪方面的应用", 《中国光学》 *
谭元捷: "基于视觉伺服的移动机械臂抓取研究", 《中国硕士学位论文全文数据库（电子期刊）信息科技辑》 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113117943A (en) * 2021-04-30 2021-07-16 泉州华中科技大学智能制造研究院 Robot spraying method and device for shoe material spraying
CN113814985A (en) * 2021-10-29 2021-12-21 遨博（北京）智能科技有限公司 Robot control method, control cabinet and system
CN114161399A (en) * 2021-12-20 2022-03-11 大连理工大学 Six-degree-of-freedom mechanical arm Cartesian space moving target real-time tracking control method
CN114161399B (en) * 2021-12-20 2023-08-18 大连理工大学 Real-time tracking control method for six-degree-of-freedom mechanical arm Cartesian space moving target
CN116512237A (en) * 2022-11-28 2023-08-01 广东建石科技有限公司 Industrial robot vision servo method, device, electronic equipment and storage medium
CN116512237B (en) * 2022-11-28 2023-09-19 广东建石科技有限公司 Industrial robot vision servo method, device, electronic equipment and storage medium

Similar Documents

Publication Publication Date Title
CN112621746A (en) PID control method with dead zone and mechanical arm visual servo grabbing system
CN109397249B (en) Method for positioning and grabbing robot system by two-dimensional code based on visual identification
CN110825076B (en) Mobile robot formation navigation semi-autonomous control method based on sight line and force feedback
CN111390872A (en) Double-arm cooperative flexible dragging and butt joint inverse operation method for extravehicular robot
CN111015649B (en) Driving and controlling integrated control system
CN112894812A (en) Visual servo trajectory tracking control method and system for mechanical arm
Yang et al. An optimized image-based visual servo control for fixed-wing unmanned aerial vehicle target tracking with fixed camera
Luo et al. Repulsive reaction vector generator for whole-arm collision avoidance of 7-DoF redundant robot manipulator
Li et al. A hybrid visual servo control method for simultaneously controlling a nonholonomic mobile and a manipulator
Han et al. Grasping control method of manipulator based on binocular vision combining target detection and trajectory planning
Fang et al. Visual grasping for a lightweight aerial manipulator based on NSGA-II and kinematic compensation
CN111702787B (en) Man-machine cooperation control system and control method
Li et al. Modified Bug Algorithm with Proximity Sensors to Reduce Human-Cobot Collisions
Zhang et al. A task-priority coordinated motion planner combined with visual servo for mobile manipulator
Tongloy et al. An image-based visual servo control system based on an eye-in-hand monocular camera for autonomous robotic grasping
CN114378827B (en) Dynamic target tracking and grabbing method based on overall control of mobile mechanical arm
Ling et al. Design and research of the multifunctional mobile manipulator based on ROS
CN114888768A (en) Mobile duplex robot cooperative grabbing system and method based on multi-sensor fusion
Guangyao et al. Visual servo control of omnidirectional mobile manipulator
Bae et al. A dynamic visual servoing of robot manipulator with eye-in-hand camera
Lang et al. Visual servoing with LQR control for mobile robots
Kebritchi et al. Design and Development of an Omnidirectional Mobile Manipulator for Indoor Environment
Hu et al. Manipulator arm interactive control in unknown underwater environment
Matsumoto et al. Operation assist for a teleoperated robot system controlled with a lightweight and high-operable master device
Borisov et al. Case study on human-free water heaters production for industry 4.0

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20210409