CN110480659B - A vibration control device and method when a robot manipulates the movement of a flexible workpiece - Google Patents

Abstract

The invention discloses a vibration control device and a method when a robot controls a flexible workpiece to move, wherein the vibration control device comprises a data processing module, a motion testing module and a signal acquisition module; the data processing module adopts an industrial personal computer and comprises a man-machine interaction unit, a real-time control unit and a vibration suppression algorithm realization unit; the motion module comprises a six-degree-of-freedom serial joint type robot and a flexible workpiece, and the flexible workpiece is arranged on a flange plate at the tail end of the robot; the signal acquisition module comprises a three-dimensional acceleration sensor, a switching power supply and a data acquisition unit, wherein the three-dimensional acceleration sensor is arranged at the tail end of the flexible workpiece. The method can effectively solve the problem of robot track planning under the working condition of fixed task duration, effectively inhibit the residual vibration of the flexible workpiece controlled by the robot, and realize accurate positioning of the workpiece.

Description

A vibration control device and method when a robot manipulates the movement of a flexible workpiece

technical field

The invention relates to the field of vibration control of industrial robots, in particular to a vibration control device and method when a robot manipulates the movement of a flexible workpiece.

Background technique

The scene where the robot manipulates the flexible load is very common in the industrial production line, and when the robot manipulates the flexible load, vibration will inevitably occur. In order to improve production efficiency and production quality, it is very important to solve the problem of residual vibration of the flexible load of. Moreover, the actual production line often has strict requirements on the running time of the robot, and the traditional speed planning method cannot predetermine the total running time of the planned trajectory. However, in the method of trajectory planning based on dynamic filtering, the only design parameter of this method is the duration parameter of the filter. Under the constraints of relevant maximum speed, maximum acceleration and other constraints and boundary conditions, the time length parameters of each filter can be easily calculated, so that the total running time of the planned trajectory can be well adjusted, which perfectly solves the problem of actual production. There are tasks that have strict requirements on the running time of the robot. As a feed-forward control method, pulse shaping technology can effectively suppress the residual vibration of the flexible system and greatly reduce the stabilization time of the system. The basic idea is to construct a pulse sequence with a specific amplitude and action time, and then convolve the pulse sequence with the original input signal of the system to re-drive the system operation with the shaped signal, so the pulse sequence is also called shaper.

Contents of the invention

The purpose of the present invention is to provide a vibration control device when a robot manipulates the movement of a flexible workpiece. The device can control the motion of a six-degree-of-freedom serial jointed robot in real time, and is convenient for testing the trajectory generated based on dynamic filtering. The residual vibration signal of the flexible workpiece.

Another object of the present invention is to provide a method for suppressing residual vibration when a robot manipulates the movement of a flexible workpiece, aiming at effectively suppressing the residual vibration of the flexible workpiece while meeting the requirement of a fixed task duration.

The purpose of the present invention can be achieved through the following technical solutions:

A vibration control device when a robot manipulates the movement of a flexible workpiece, including: a data processing module, a motion testing module, and a signal acquisition module;

The data processing module adopts an industrial computer, including a human-computer interaction unit, a real-time control unit and a vibration suppression algorithm realization unit, and the human-computer interaction unit is used to display the interface of the robot running state and the operation interface of the control algorithm executor; The real-time control unit is used to control the operation of the robot in real time; the vibration suppression algorithm implementation unit includes a track generator for designing the running track of the robot;

The motion test module includes a six-degree-of-freedom serial articulated robot and a flexible workpiece; the six-degree-of-freedom serial articulated robot realizes real-time motion through a trajectory generated by a data processing module, and the flexible workpiece is installed on a flange at the end of the robot;

The signal acquisition module includes a three-dimensional acceleration sensor, a switching power supply and a data collector, the three-dimensional acceleration sensor is installed at the end of the flexible workpiece, the switching power supply is used to provide a constant voltage for the acceleration sensor and the data collector, and the data acquisition The device is used to convert the analog signal collected by the three-dimensional acceleration sensor into a digital signal and then send it to the data processing module.

Further, the real-time control unit is connected to the AC servo driver of each joint of the six-degree-of-freedom series articulated robot through EtherCAT, and sends the displacement track to the AC servo driver at a time interval of 1 ms, and the AC servo driver Control the corresponding joint servo motor to control the operation of the six-degree-of-freedom serial joint robot in real time.

Further, the human-computer interaction unit includes a display interface and a control algorithm executor, the display interface is used to monitor the operating conditions of each joint of the robot; the control algorithm executor is used to set the parameters related to the vibration suppression algorithm and the control mode switch.

Another object of the present invention can be achieved through the following technical solutions:

The vibration control method when the robot manipulating the flexible workpiece motion based on the test device comprises the following steps:

S1. The basic trajectory is generated by the trajectory generator in the data processing module, and the six-degree-of-freedom series articulated robot runs according to the basic trajectory; the three-dimensional acceleration sensor collects the residual vibration signal at the end of the flexible workpiece;

S2. Identifying the modal parameters of the collected residual vibration signals;

S3. Design a zero-vibration (ZV) type input shaper according to the identified modal parameters:

ζ为阻尼系数，δ(t)为脉冲函数；in:

ζ is the damping coefficient, δ(t) is the pulse function;

S4. Redesign the running trajectory of the robot through the trajectory generator to meet the requirements of the fixed task duration;

S5. Reshaping the redesigned running trajectory to complete the vibration control when the robot manipulates the flexible workpiece.

Further, the step S1 specifically includes:

S101. The industrial computer discretely processes the displacement signal and sends it to the AC servo controller of each joint of the robot at a time interval of 1 ms. The joint servo motor drives the mechanical arm to move according to the displacement input signal;

S102. When the displacement input signal ends, the three-dimensional acceleration sensor synchronously collects the vibration signal at the end of the flexible arm, and the data collector performs discrete processing on the residual vibration signal collected by the three-dimensional acceleration sensor and sends it back to the industrial computer.

Further, the step S2 specifically includes:

S201. Obtain the frequency spectrum of the residual vibration signal through fast Fourier transform, and then obtain the vibration frequency;

S202. Obtain a damping coefficient through a logarithmic decay method.

Further, the step S4 specifically includes:

S401. Obtain the duration of trajectory planning under the condition of fixed task duration:

T＝T _total -T _IS (11)

Among them: T _total is the total duration of the task, and T _IS is the duration of the shaper;

S402, by performing speed planning based on dynamic filtering, and then generating a running trajectory, the transfer function of the dynamic filter is:

Among them, T _i is the duration of the i-th filter;

The time domain function corresponding to the filter is:

Where: T _i is the duration of the i-th filter, u(t) is a step function;

The nth-order trajectory obtained by dynamic filtering:

q _n (t)=hu(t)*m ₁ (t)*m ₂ (t)*...*m _n (t) (14)

Where: h is the total length of the trajectory.

Further, the step S5 specifically includes:

S501. Redesign the running track duration:

S502. Reshaping the redesigned running trajectory:

q _IS (t)=q _n (t)*f _IS (t) (16)

S502. Using the shaped signal q _IS (t) as an input signal of the robot to realize vibration control when the robot manipulates the flexible workpiece.

Compared with the prior art, the present invention has the following advantages and effects:

The present invention can accurately and quickly obtain the modal parameters required for designing the input shaper by performing time-domain analysis and frequency-domain analysis on the residual vibration signal; realizing trajectory planning based on dynamic filtering can meet the requirement of fixed task duration; the present invention can Effectively suppress the residual vibration when the robot manipulates the movement of the flexible workpiece, improve the tracking accuracy of the flexible workpiece, realize the fast and accurate positioning of the flexible workpiece, and improve the production quality and efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the appearance structure of the vibration control test device when the robot manipulates the movement of the flexible workpiece in the present invention.

Fig. 2 is a schematic diagram of the principles of each module of the vibration control testing device when the robot manipulates the movement of the flexible workpiece in the present invention.

Fig. 3 is a schematic flow chart of the vibration control method when the robot manipulates the movement of the flexible workpiece in the present invention.

In the figure: 1-three-dimensional acceleration sensor; 2-flexible workpiece; 3-six-DOF serial joint robot; 4-joint servo motor; 5-base.

detailed description

The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example

Now take a six-degree-of-freedom series-joint industrial robot manipulating a flexible workpiece as the vibration control object as an example to further illustrate the present invention.

As shown in Figure 1, the test device of the vibration control when the robot of the present embodiment manipulates the flexible workpiece motion, the test device includes: a data processing module, a motion test module, and a signal acquisition module;

The data processing module adopts Huayan IPC-510 embedded industrial computer, including a human-computer interaction unit, a real-time control unit, and a vibration suppression algorithm realization unit; the human-computer interaction unit, real-time control unit, and vibration suppression algorithm realization unit are all in Developed on the Microsoft Visual Studio 2017 platform, the anti-vibration algorithm implementation unit includes a trajectory generator for designing the trajectory of the robot; the real-time control unit is connected to the servo driver through EtherCAT, and the displacement trajectory is sent to the robot at an interval of 1ms. The AC servo driver for each joint of the six-degree-of-freedom series-joint robot 3, the AC servo driver controls the corresponding joint servo motor 4 to control the operation of the six-degree-of-freedom series-joint robot 3 in real time, and the six-degree-of-freedom series-joint robot 3 Set on the base 5. The human-computer interaction unit includes a display interface and a control algorithm executor, the display interface is used to monitor the operation status of each joint of the robot; the control algorithm executor is used to set parameters related to the vibration suppression algorithm and switch control modes.

The signal acquisition module includes a three-dimensional acceleration sensor, a switching power supply and a data collector, and the three-dimensional acceleration sensor 8 adopts the 8395A type three-dimensional acceleration sensor of the German KISTLER company, and the measurement range is -300m/s ² ~+300m/s ² ; The switching power supply adopts the NES-150-24 switching power supply produced by MEAN WELL Company; the data collector adopts the EK1100 module produced by German Beckhoff Automation Co., Ltd.; the three-dimensional acceleration sensor 1 is installed at the end of the flexible workpiece 2, and the The switching power supply provides a 24v constant voltage for the acceleration sensor 1 and the data collector, and the data collector converts the analog signal collected by the three-dimensional acceleration sensor 3 into a digital signal and sends it back to the industrial computer.

As shown in Figure 2, a vibration control method when a robot manipulates the movement of a flexible workpiece includes the following steps:

S1. The basic trajectory is generated by the trajectory generator, the six-degree-of-freedom series articulated robot runs according to the basic trajectory, and the three-dimensional acceleration sensor collects the residual vibration signal at the end of the flexible workpiece;

S2. Identifying the modal parameters of the collected residual vibration signals;

S3. Design a zero-vibration (ZV) type input shaper according to the identified modal parameters:

ζ为阻尼系数，δ(t)为脉冲函数；in:

ζ is the damping coefficient, δ(t) is the pulse function;

S4. Redesign the trajectory of the robot through the trajectory generator to meet the requirements of the fixed task duration;

S5. Reshaping the redesigned running trajectory to complete the vibration control when the robot manipulates the flexible workpiece.

Specifically, the step S1 specifically includes:

S101. The industrial computer discretely processes the displacement signal and sends it to the AC servo controller of each joint of the robot at a time interval of 1 ms. The joint servo motor drives the mechanical arm to move according to the displacement input signal;

S102. When the displacement input signal ends, the three-dimensional acceleration sensor synchronously collects the vibration signal at the end of the flexible arm, and the data collector performs discrete processing on the residual vibration signal collected by the three-dimensional acceleration sensor and sends it back to the industrial computer.

Specifically, the step S2 specifically includes:

S201. Obtain the frequency spectrum of the residual vibration signal through fast Fourier transform, and then obtain the vibration frequency;

S202. Obtain a damping coefficient through a logarithmic decay method.

Specifically, the step S4 specifically includes:

Described step S4 specifically comprises:

S401. Obtain the duration of trajectory planning under the condition of fixed task duration:

T＝T _total -T _IS (19)

Among them: T _total is the total duration of the task, and T _IS is the duration of the shaper;

S402, by performing speed planning based on dynamic filtering, and then generating a running trajectory, the transfer function of the dynamic filter is:

Among them, T _i is the duration of the i-th filter;

The time domain function corresponding to the filter is:

Where: T _i is the duration of the i-th filter, u(t) is a step function;

The nth-order trajectory obtained by dynamic filtering:

q _n (t)＝hu(t)*m ₁ (t)*m ₂ (t)*...*m _n (t) (22)

Where: h is the total length of the trajectory.

Specifically, the step S5 specifically includes:

S501. The duration of the redesigned running track is

S502. Reshaping the redesigned running trajectory

q _IS (t)＝q _n (t)*f _IS (t) (24)

S502. Using the shaped signal q _IS (t) as an input signal of the robot to realize vibration control when the robot manipulates the flexible workpiece.

The above-mentioned embodiments are only for clearly illustrating the present invention, and are preferred implementation modes of the present invention, rather than limiting the implementation modes of the present invention. Under the premise of not departing from the spirit and scope of the present invention, the present invention also has various changes and deformations, and these obvious changes and deformations that belong to the essential spirit of the present invention are still included in the protection scope of the present invention Inside.

Claims (6)

1. a vibration control method when a robot manipulates a flexible workpiece motion, it is characterized in that the method is realized based on a vibration control device when a robot manipulates a flexible workpiece motion, and the device includes: a data processing module, a motion testing module, Signal acquisition module; the data processing module adopts an industrial computer, including a human-computer interaction unit, a real-time control unit and a vibration suppression algorithm realization unit, and the human-computer interaction unit is used to display the interface of the robot running state and the control algorithm executor Operation interface; the real-time control unit is used to control the operation of the robot in real time; the vibration suppression algorithm implementation unit includes a trajectory generator, and the trajectory generator is used to generate the running trajectory of the robot to meet the requirements of the fixed task duration; The motion test module includes a six-degree-of-freedom serial articulated robot and a flexible workpiece; the six-degree-of-freedom serial articulated robot realizes real-time motion through a trajectory generated by a data processing module, and the flexible workpiece is installed on a flange at the end of the robot; The signal acquisition module includes a three-dimensional acceleration sensor, a switching power supply and a data collector. The three-dimensional acceleration sensor is installed at the end of the flexible workpiece. The switching power supply is used to provide a constant voltage for the acceleration sensor and the data collector. The data collector is used for Converting the analog signal collected by the three-dimensional acceleration sensor into a digital signal and sending it to the data processing module; The method comprises the steps of: S1. The basic trajectory is generated by the trajectory generator in the data processing module, and the six-degree-of-freedom series articulated robot runs according to the basic trajectory; the three-dimensional acceleration sensor collects the residual vibration signal at the end of the flexible workpiece; S2. Identifying the modal parameters of the collected residual vibration signals; S3. Design a zero-vibration input shaper according to the identified modal parameters:

in:

ζ is the damping coefficient, δ(t) is the pulse function; S4. The trajectory generator performs speed planning based on dynamic filtering, and redesigns the running trajectory of the robot to meet the requirements of the fixed task duration; S5. Reshape the redesigned running trajectory to complete the vibration control when the robot manipulates the flexible workpiece; Step S4 specifically includes: S401. Obtain the duration of trajectory planning under the condition of fixed task duration: T＝T _total -T _IS (3) Among them: T _total is the total duration of the task, and T _IS is the duration of the shaper; S402, by performing speed planning based on dynamic filtering, and then generating a running trajectory, the transfer function of the dynamic filter is:

Among them, T _i is the duration of the i-th filter; The time domain function corresponding to the filter is:

Where: T _i is the duration of the i-th filter, u(t) is a step function; The nth-order trajectory obtained by dynamic filtering: q _n (t)＝hu(t)*m ₁ (t)*m ₂ (t)*...*m _n (t) (6) Where: h is the total length of the trajectory. 2. The vibration control method when a robot manipulates a flexible workpiece according to claim 1, characterized in that: in the device, the real-time control unit is connected to the six-degree-of-freedom series articulated robot through the EtherCAT mode. The AC servo driver of the joint is connected, and the displacement track is sent to the AC servo driver at a time interval of 1 ms, and the AC servo driver controls the corresponding joint servo motor to control the operation of the six-degree-of-freedom series articulated robot in real time. 3. The vibration control method when a robot manipulates a flexible workpiece according to claim 1, wherein in the device, the human-computer interaction unit includes a display interface and a control algorithm executor, and the display The interface is used to monitor the running status of each joint of the robot; the control algorithm executor is used to set parameters related to the vibration suppression algorithm and switch control modes. 4. The vibration control method when a robot manipulates a flexible workpiece according to claim 1, wherein the step S1 specifically includes: S101. The industrial computer discretely processes the displacement signal and sends it to the AC servo controller of each joint of the robot at a time interval of 1 ms. The joint servo motor drives the mechanical arm to move according to the displacement input signal; S102. When the displacement input signal ends, the three-dimensional acceleration sensor synchronously collects vibration signals at the end of the flexible arm, and the data collector performs discrete processing on the residual vibration signals collected by the three-dimensional acceleration sensor and sends them back to the industrial computer. 5. The vibration control method when the robot manipulates the flexible workpiece according to claim 1, wherein the step S2 specifically comprises: S201. Obtain the frequency spectrum of the residual vibration signal through fast Fourier transform, and then obtain the vibration frequency; S202. Obtain a damping coefficient through a logarithmic decay method. 6. The vibration control method when the robot manipulates the flexible workpiece according to claim 1, wherein the step S5 specifically comprises: S501. Redesign the running track duration:

S502. Reshaping the redesigned running trajectory: q _IS (t)＝q _n (t)*f _IS (t) (8) S502. Using the shaped signal q _IS (t) as an input signal of the robot to realize vibration control when the robot manipulates the flexible workpiece.

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