CN107160367B - Control device and method for planar two-degree-of-freedom parallel mechanism - Google Patents

Abstract

The invention discloses a control device and a control method for a plane two-degree-of-freedom parallel mechanism, wherein the device comprises a parallel mechanism body and a control unit, and the parallel mechanism body comprises a movable platform, a driven movement branched chain and two driving movement branched chains; the driven movement branched chain comprises a first supporting piece, a second supporting piece, a first rigid primary rod, a second rigid primary rod, a first rigid secondary rod, a second rigid secondary rod and a first connecting rod; each active movement branched chain comprises a direct drive rotating motor, a third supporting piece, a third rigid primary rod, a fourth rigid primary rod, a third rigid secondary rod, a fourth rigid secondary rod and a second connecting rod; the movable platform is provided with an acceleration sensor, a first side of the acceleration sensor is connected with the driven movement branched chain, and a second side and a third side of the acceleration sensor are respectively connected with the two driving movement branched chains; the control unit is respectively connected with the direct drive rotating motor and the acceleration sensor. The invention has the advantages of high control precision, quick response, good rigidity and simple structure, and has high practicability.

Description

Control device and method for planar two-degree-of-freedom parallel mechanism

technical field

The invention relates to a parallel mechanism control device, in particular to a planar two-degree-of-freedom parallel mechanism control device and method, belonging to the field of motion control of planar mechanisms.

Background technique

At present, with the development of technology, more and more robotic devices are used in industrial production. In order to improve production efficiency and product quality, the requirements for the speed and precision of robotic devices are also getting higher and higher. Traditional robotic devices mostly use motor accelerators or hydraulic drives. The drive methods of motor accelerators often bring about unavoidable problems such as large internal friction, increased moment of inertia, and backlash. The friction, tooth backlash, and elastic deformation will cause nonlinearity, resulting in unsatisfactory control bandwidth and operability of the robot device, and it is difficult to meet the requirements of high speed and high precision. The hydraulic drive also has the disadvantages of poor reliability and difficult maintenance. .

Contents of the invention

The object of the present invention is to solve the above-mentioned defects in the prior art, and to provide a planar two-degree-of-freedom parallel mechanism control device, which drives the dynamic platform through the design of three kinematic branch chains composed of rigid rods, and two of them The motion branch chain is directly driven by a suitable direct drive rotating motor, which has the advantages of high control precision, fast response, good rigidity, and simple structure, and has high practicability.

Another object of the present invention is to provide a method for controlling a plane two-degree-of-freedom parallel mechanism based on the above device.

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

A planar two-degree-of-freedom parallel mechanism control device includes a parallel mechanism body and a control unit, and the parallel mechanism body includes a moving platform, a driven motion branch chain, and two active motion branch chains;

The driven motion branch chain includes a first support member, a second support member, a first rigid primary rod, a second rigid primary rod, a first rigid secondary rod, a second rigid secondary rod and a first connecting rod , the first support, the first rigid primary rod and the first rigid secondary rod are connected in sequence, the second support, the second rigid primary rod and the second rigid secondary rod are connected in sequence, the first rigid primary rod and The connection between the first rigid two-stage rod and the connection between the second rigid one-stage rod and the second rigid two-stage rod are connected through the first connecting rod;

Each active motion leg includes a direct drive rotary motor with an encoder, a third support, a third rigid primary rod, a fourth rigid primary rod, a third rigid secondary rod, a fourth rigid secondary rod, and The second connecting rod, the direct drive rotary motor, the third rigid primary rod and the third rigid secondary rod are sequentially connected, and the third support member, the fourth rigid primary rod and the fourth rigid secondary rod are sequentially connected , the connection between the third rigid primary rod and the third rigid secondary rod is connected with the connection between the fourth rigid primary rod and the fourth rigid secondary rod through the second connecting rod;

The shape of the moving platform is an equilateral triangle, which is provided with an acceleration sensor. The first side of the moving platform is connected to the first rigid secondary rod and the second rigid secondary rod of the driven motion branch chain, and the second side is connected to one of the The third rigid secondary rod and the fourth rigid secondary rod of the active motion branch chain are connected, and the third side is connected with the third rigid secondary rod and the fourth rigid secondary rod of another active motion branch chain;

The control unit is respectively connected with the direct drive rotating motor and the acceleration sensor.

Further, two holes are provided on the three sides of the moving platform, and the two holes on the first side of the moving platform pass through the first rotating shaft and the first rigid two-stage rod and the second rigid two-stage rod of the driven motion branch chain respectively. The two holes on the second side are respectively connected to the third rigid secondary rod and the fourth rigid secondary rod of one of the active motion branch chains through the second rotating shaft, and the two holes on the third side are respectively connected to the third rigid secondary rod through the third The rotating shaft is connected with the third rigid secondary rod and the fourth rigid secondary rod of another active motion branch chain.

Further, the first supporting member is provided with a fourth rotating shaft, the fourth rotating shaft is provided with a first sleeve through a bearing sleeve, one end of the first rigid primary rod is fixed on the first sleeve, and the first rigid The other end of the primary rod is hinged to one end of the first rigid secondary rod through the fifth rotating shaft, and the fifth rotating shaft is provided with a second sleeve through the bearing sleeve;

The second supporting member is provided with a sixth rotating shaft, the sixth rotating shaft is provided with a third sleeve through a bearing sleeve, one end of the second rigid primary rod is fixed on the third sleeve, and the second rigid primary rod The other end of the shaft is hinged to one end of the second rigid secondary rod through the seventh shaft, and the seventh shaft is provided with a fourth sleeve through the bearing sleeve;

The other end of the first rigid secondary rod and the other end of the second rigid secondary rod are hinged to the two holes on the first side of the moving platform through the first rotating shaft respectively; the two ends of the first connecting rod are respectively fixed on on the second and fourth sleeves.

Further, the direct drive rotary motor is connected to one end of the third rigid primary rod through a flange, the flange is fixed on the rotor of the direct drive rotary motor, and one end of the third rigid primary rod is fixed on the French On the blue, the other end of the third rigid primary rod is hinged to one end of the third rigid secondary rod through the eighth rotating shaft, and the eighth rotating shaft is provided with a fifth sleeve through the bearing sleeve;

The third supporting member is provided with a ninth rotating shaft, the ninth rotating shaft is provided with a sixth sleeve through a bearing sleeve, one end of the fourth rigid primary rod is fixed on the sixth sleeve, and the fourth rigid primary rod The other end of the shaft is hinged to one end of the fourth rigid secondary rod through the tenth shaft, and the tenth shaft is provided with a seventh sleeve through the bearing sleeve;

For one of the active motion branch chains, the other end of the third rigid secondary rod and the other end of the fourth rigid secondary rod are respectively hinged to the two holes on the second side of the moving platform through the second rotating shaft; for the other active motion support chain, the other end of the third rigid secondary rod and the other end of the fourth rigid secondary rod are respectively hinged to the two holes on the third side of the moving platform through the second rotating shaft; the two ends of the second connecting rod are respectively fixed on On the fifth and seventh sleeves.

Further, the first rigid primary rod, the first rigid secondary rod and the first connecting rod form a first compound hinge structure, and the second rigid primary rod, the second rigid secondary rod and the first connecting rod Constitute a second composite hinge structure, the third rigid primary rod, the third rigid secondary rod and the second connecting rod constitute a third composite hinge structure, the fourth rigid primary rod, the fourth rigid secondary rod and The second connecting rod constitutes the fourth composite hinge structure;

The first rigid primary rod, the second rigid primary rod, the third rigid primary rod and the fourth rigid primary rod have the same length, the first rigid secondary rod, the second rigid secondary rod, the first rigid secondary rod The lengths of the three rigid secondary rods and the fourth rigid secondary rods are the same; The distance between the axis of the first support and the second support, the distance between the direct drive rotary motor and the axis of the third support, and the distance between the axes of the two holes on each side of the moving platform are the same.

Further, the line between the axes of the two holes on the first side of the moving platform, the first rigid secondary rod, the second rigid secondary rod, and the first connecting rod of the driven motion branch chain constitute a first parallel Quadrilateral structure, the line between the first connecting rod of the driven motion branch chain, the first rigid primary rod, the second rigid primary rod, the axis of the first support and the second support constitutes a second parallelogram structure ;

The connecting line between the axes of the two holes on the second side of the moving platform forms a third parallelogram structure with the third rigid secondary rod, the fourth rigid secondary rod and the second connecting rod of an active motion branch chain, The connecting line between the second connecting rod, the third rigid one-stage rod, the fourth rigid one-stage rod, the direct drive rotating motor and the axis of the third support member of the active motion branch chain forms a fourth parallelogram structure;

The connecting line between the axes of the two holes on the third side of the moving platform forms a fifth parallelogram structure with the third rigid secondary rod, the fourth rigid secondary rod and the second connecting rod of another active motion branch chain , the connection line between the second connecting rod, the third rigid one-stage rod, the fourth rigid one-stage rod, the direct drive rotating motor and the axis of the third support member of the active motion branch chain forms a sixth parallelogram structure.

Further, the encoder is arranged inside the direct drive rotating motor, and the acceleration sensor is arranged at the center of the upper surface of the moving platform.

Further, the parallel mechanism body also includes a static platform, the static platform includes a base plate, four supporting feet are provided at the bottom of the base plate, and a transverse bracket is installed between every two adjacent supporting feet;

The first support piece and the second support piece of the driven motion branch chain, the direct drive rotary motors and the third support piece of the two active movement branch chains are all fixed on the base plate of the static platform.

Further, the control unit includes a computer, a motion control card, a terminal board, and a direct drive rotary motor servo drive unit, the computer is connected to the motion control card, and the motion control card integrates A/D conversion and pulse counting functions, And connected with the terminal board, the terminal board is respectively connected with the encoder, the acceleration sensor and the servo drive unit of the direct drive rotary motor, and the servo drive unit of the direct drive rotary motor is connected with the direct drive rotary motor;

The acceleration sensor measures the acceleration signals of the moving platform in two directions on the horizontal plane. The acceleration signals are input to the motion control card through the terminal board for A/D conversion to obtain digital signals, and the computer processes the digital signals to obtain the feedback signals of the moving platform. ;

The encoder measures the angular displacement signal that directly drives the rotation of the rotating motor, and the angular displacement signal is input to the motion control card through the terminal board for pulse counting to obtain a digital signal, and the computer processes the digital signal to obtain an output signal that directly drives the rotating motor;

The computer obtains the control signal according to the feedback signal of the moving platform and the output signal of the direct drive rotary motor, and the control signal is input to the servo drive unit of the direct drive rotary motor through the motion control card and the terminal board to control the output of the direct drive rotary motor to realize the motion control. Motion control of the platform.

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

Based on the control method of the plane two-degree-of-freedom parallel mechanism of the above-mentioned device, the method comprises the following steps:

Step 1. The acceleration sensor on the moving platform measures the acceleration signals along the X and Y directions of the moving platform during the horizontal plane translation movement, and performs kinematic inverse solution on the acceleration signals to obtain the angular velocity and angular acceleration component signals of the direct drive rotating motor ;

Step 2. Input the analog signal measured in step 1 to the motion control card through the terminal board for A/D conversion to obtain a digital signal, and process the digital signal by the computer to obtain the feedback signal of the moving platform;

Step 3: Measure the encoder of the direct drive rotary motor to obtain the rotation angle displacement signal of the direct drive rotary motor. The angular displacement signal is input to the motion control card through the terminal board for pulse counting to obtain a digital signal, and the computer processes the digital signal to obtain a direct drive. The output signal of the rotating electrical machine;

Step 4. After the computer compares the output signal of the direct drive rotating motor with the feedback signal of the moving platform, compares it with the expected motion and position parameters, and then runs the corresponding control algorithm to obtain the required control signal. The control signal is input to the direct drive rotary motor servo drive unit through the motion control card and terminal board, and the direct drive rotary motor servo unit controls the output of the direct drive rotary motor according to the control signal, so as to achieve the purpose of controlling the motion of the moving platform.

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

1. The present invention designs three kinematic branch chains, one of which is used as a driven kinematic branch chain, and the other two are used as active kinematic branch chains. The two active kinematic branch chains adopt a direct-drive driving method without passing through a reducer or other intermediate The transmission mechanism reduces the influence of friction, has no backlash problem, and has a simpler and more compact mechanical structure, which greatly improves the motion control accuracy and response speed of the mechanism, with higher reliability and easier maintenance; in addition , There is an acceleration sensor on the moving platform, which can measure the acceleration signals along the two directions on the horizontal plane when the moving platform is moving. The direct drive rotary motor has an encoder, which can measure the angular displacement signal when the direct drive rotary motor rotates. According to the acceleration sensor The motion parameters measured with the parameters measured by the encoder realize the control of the moving platform.

2. The connecting line between the two primary rods, the connecting rod, the direct drive rotary motor and the axis of the support in the active motion branch chain of the present invention forms a parallelogram structure, the connecting rod, the two secondary rods, The connection between the axes of the two holes on the same side of the moving platform also forms a parallelogram structure, and the two first-stage rods, connecting rods, and axes of the two support members in the driven motion branch chain The connection lines of the connecting rods, the two secondary rods, and the axes of the two holes on the same side of the moving platform also form a parallelogram structure, that is, three kinematic branch chains Both have two parallelogram structures, which constrain the moving platform to only do translational movement on the horizontal plane. It has two degrees of freedom. The two-degree-of-freedom moving platform is easy to control, stable in structure, and widely used.

3. The present invention adopts a motion control loop with feedback, and an acceleration sensor is arranged at the center of the upper surface of the moving platform, which can measure the acceleration signals along two directions on the horizontal plane when the moving platform moves, and an encoder is arranged inside the direct drive rotating motor, It can measure the angular displacement signal when directly driving the rotating motor. The parameters measured by the acceleration sensor and the encoder are input to the motion control card through the terminal board to process the digital signal, and the digital signal is processed by the computer to obtain the control signal. The control signal controls the direct drive. The rotary motor servo unit is used to control the output of the direct drive rotary motor, thereby controlling the motion of the braking platform.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of a planar two-degree-of-freedom parallel mechanism control device according to Embodiment 1 of the present invention.

Fig. 2 is a top view of the parallel mechanism body in the planar two-degree-of-freedom parallel mechanism control device according to Embodiment 1 of the present invention.

Fig. 3 is a schematic structural diagram of the driven motion branch chain of the parallel mechanism body in the planar two-degree-of-freedom parallel mechanism control device according to Embodiment 1 of the present invention.

4 is a schematic structural diagram of one of the active motion branch chains of the parallel mechanism body in the planar two-degree-of-freedom parallel mechanism control device according to Embodiment 1 of the present invention.

Among them, 1-moving platform, 2-static platform, 3-acceleration sensor, 4-substrate, 5-support feet, 6-horizontal support, 7-first support, 8-second support, 9-first rigidity One-stage rod, 10-the second rigid one-stage rod, 11-the first rigid two-stage rod, 12-the second rigid two-stage rod, 13-the first connecting rod, 14-the first sleeve, 15-the second set Cylinder, 16-third sleeve, 17-fourth sleeve, 18-direct drive rotary motor, 19-third support, 20-third rigid primary rod, 21-fourth rigid primary rod, 22- The third rigid secondary rod, 23-the fourth rigid secondary rod, 24-the second connecting rod, 25-flange, 26-the fifth sleeve, 27-the sixth sleeve, 28-the seventh sleeve, 29 - computer, 30 - motion control card, 31 - terminal board, 32 - direct drive rotary motor servo drive unit.

Detailed ways

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

Example 1:

This embodiment designs a reasonable mechanical structure, selects a suitable direct-drive rotating motor, builds a coordinated drive control system, and provides a planar two-degree-of-freedom parallel mechanism control device. The device adopts a direct drive mode, omitting the intermediate transmission device, Directly connecting the load with the drive motor can fundamentally solve various problems caused by the use of the transmission device, and greatly improve the control bandwidth and operability of the parallel mechanism. It has high speed, high precision, light weight, small size and high rigidity. , Simple maintenance, simple mechanical structure design, high reliability, good speed regulation and so on.

As shown in Figures 1 and 2, the planar two-degree-of-freedom parallel mechanism control device of this embodiment includes a parallel mechanism body and a control unit, and the parallel mechanism body includes a moving platform 1, a static platform 2, and three kinematic branch chains, wherein One kinematic branch is a driven kinematic branch, and the other two kinematic branches are active kinematic branches; the dotted line connection in Figure 1 represents the connection diagram of the electrical signal and the body of the parallel mechanism, and the direction arrows indicate the flow of detection and control signals Pass direction.

The moving platform 1 is an equilateral triangular disc-shaped platform, with two holes on its three sides, the two holes on the first side of the moving platform are respectively connected with the driven movement branch chain through the first rotating shaft, and the second side The two holes on the first side, the second side and the third side are connected to an active kinematic branch chain through the second shaft, the two holes on the third side are connected to another active kinematic branch chain through the third shaft, and the two holes on the first side, the second side and the third side The distances between the axes of the holes are all the same; the moving platform 1 is provided with an acceleration sensor 3, specifically, the acceleration sensor 3 is installed at the center of the upper surface of the moving platform 1, and the acceleration sensor 3 is used to measure the speed of the moving platform 1. Acceleration signals in two directions (X direction, Y direction) on the horizontal plane.

In this embodiment, the acceleration sensor 3 is a capacitive, low-frequency accelerometer produced by Kistler, Switzerland, whose model number is 8395A050.

The static platform 2 is used to support the dynamic platform 1 and three motion branch chains, including a base plate 4, the base plate 4 is a square base plate, and its bottom is provided with four supporting feet 5, and each two adjacent supporting feet 5 are installed A horizontal support 6 plays a stabilizing role. The base plate 4, the supporting feet 5 and the horizontal support 6 are all made of aluminum profiles.

As shown in Figures 1 to 3, the driven motion branch chain includes a first support 7, a second support 8, a first rigid primary rod 9, a second rigid primary rod 10, a first rigid secondary The rod 11, the second rigid secondary rod 12 and the first connecting rod 13, the first rigid primary rod 9, the first rigid secondary rod 11 and the first connecting rod 13 constitute the first composite hinge structure, and the second rigid primary The rod 10, the second rigid secondary rod 12 and the first connecting rod 13 form a second composite hinge structure;

The first support member 7 is fixedly installed on the base plate 4 of the static platform 2 by bolts, and it is provided with a fourth rotating shaft. The fourth rotating shaft is provided with a first sleeve 14 through a bearing sleeve, and one end of the first rigid primary rod 9 Fixed on the first sleeve 14 by screws, the other end of the first rigid primary rod 9 is hinged with one end of the first rigid secondary rod 11 through the fifth rotating shaft, and the fifth rotating shaft is provided with the second sleeve 15 through the bearing sleeve ;

The second support member 8 is fixedly installed on the base plate 4 of the static platform 2 by bolts, and it is provided with a sixth rotating shaft, and the sixth rotating shaft is provided with a third sleeve 16 through a bearing sleeve, and one end of the second rigid primary rod 10 Fixed on the third sleeve 16 by screws, the other end of the second rigid primary rod 10 is hinged with one end of the second rigid secondary rod 12 through the seventh rotating shaft, and the seventh rotating shaft is provided with a fourth sleeve 17 through a bearing sleeve. ;

The other end of the first rigid secondary rod 11 and the other end of the second rigid secondary rod 12 are respectively hinged with two holes on the first side of the moving platform 1 through the first rotating shaft; the two ends of the first connecting rod 13 are respectively It is fixed on the second sleeve 15 and the fourth sleeve 17 by screws.

The structures of the two active kinematic branch chains are exactly the same. Take one of the active kinematic branch chains as an example, as shown in Fig. 1, Fig. 2 and Fig. Stage rod 20, the fourth rigid one-stage rod 21, the third rigid two-stage rod 22, the fourth rigid two-stage rod 23 and the second connecting rod 24, the third rigid one-stage rod 20, the third rigid two-stage rod 22 and The second connecting rod 24 constitutes the third composite hinge structure, and the fourth rigid primary rod 21, the fourth rigid secondary rod 23 and the second connecting rod 24 constitute the fourth composite hinge structure;

An encoder is installed inside the direct drive rotary motor 18, and the encoder is used to measure the rotation parameter (rotational angular displacement signal) of the direct drive rotary motor 18, and the direct drive rotary motor 18 is fixedly installed on the base plate 4 of the static platform 2 by bolts , and connected to one end of the third rigid one-stage rod 20 through a flange 25, the flange 25 is fixed on the rotor of the direct drive rotary motor 18 by screws, and one end of the third rigid one-stage rod 20 is fixed on the flange 25 by screws Above, the other end of the third rigid primary rod 20 is hinged to one end of the third rigid secondary rod 22 through the eighth rotating shaft, and the eighth rotating shaft is provided with a fifth sleeve 26 through the bearing sleeve;

The third support member 19 is fixedly installed on the base plate 4 of the static platform 2 by bolts, and is provided with a ninth rotating shaft, the ninth rotating shaft is provided with a sixth sleeve 27 through a bearing sleeve, and one end of the fourth rigid primary rod 21 Fixed on the sixth sleeve 27, the other end of the fourth rigid primary rod 21 is hinged to one end of the fourth rigid secondary rod 23 through the tenth rotating shaft, and the tenth rotating shaft is provided with the seventh sleeve 28 through the bearing sleeve;

For one of the active motion branch chains, the other end of the third rigid secondary rod 22 and the other end of the fourth rigid secondary rod 23 are respectively hinged with two holes on the second side of the moving platform 1 through the second rotating shaft; for the other Active motion branch chain, the other end of the third rigid secondary rod 22 and the other end of the fourth rigid secondary rod 23 are respectively hinged with two holes on the third side of the moving platform 1 through the second rotating shaft; the second connecting rod 24 Both ends are respectively fixed on the fifth sleeve 26 and the seventh sleeve 28;

After the direct drive rotating motor 18 is driven, the third rigid primary rod 20 is driven, and then the third rigid secondary rod 22, the second connecting rod 24, the fourth rigid primary rod 21, and the fourth rigid secondary rod 23 are driven sequentially. , so that the moving platform 1 moves, and the direct drive mode is adopted. The low-speed high-torque directly drives the rotating motor 18 through the flange 25 and directly connects the third rigid first-stage rod 20 to be driven without passing through an intermediate transmission mechanism such as a reducer. , reducing the impact of friction, no backlash problem, simpler and more compact mechanical structure, greatly improving the motion control accuracy and response speed of the parallel mechanism, higher reliability, and easier maintenance.

In the present embodiment, the direct drive rotary motor 18 selects the ACW 220 type direct drive rotary motor produced by Singapore Akribis Company, and the model of the encoder inside the motor is selected as AB-7500; The length of the first stage rod 10, the third rigid one stage rod 20 and the fourth rigid one stage rod 21 are the same, and the first rigid one stage rod 9 is kept parallel to the second rigid one stage rod 10, and the third rigid one stage rod 20 and The fourth rigid one-stage rod 21 remains parallel, the first rigid two-stage rod 11, the second rigid two-stage rod 12, the third rigid two-stage rod 22 and the fourth rigid two-stage rod 23 have the same length, and the first rigid two-stage rod 23 has the same length. Level rod 11 and the second rigid secondary rod 12 keep parallel, the third rigid secondary rod 22 and the fourth rigid secondary rod 23 keep parallel; the distance between the first support member and the second support member axis, the first The distance between the axes of the compound hinge structure and the second compound hinge structure and the distance between the axes of the two holes on the first side of the moving platform 1 are the same, and the distance between the axes of the two holes on the first side of the moving platform 1 The connecting line is kept parallel to the first connecting rod 13, and the connecting line between the axes of the two holes on the first side of the moving platform 1 is kept parallel to the connecting line between the axes of the first support member 7 and the second support member 8 ; the distance between the axis of the third compound hinge structure and the fourth compound hinge structure, the distance between the axis of the direct drive rotary motor 18 and the third support member 19, and the distance between the second side (or the third side) of the moving platform 1 The distance between the axes of the two holes is the same, the line between the axes of the two holes on the second side (or third side) of the moving platform 1 is kept parallel to the second connecting rod 24, and the second connecting rod 24 of the moving platform 1 The line between the axes of the two holes on the side (or the third side) is kept parallel to the line between the axes of the direct drive rotary motor 18 and the third support member 19;

The connecting line between the two hole axes on the first side of the moving platform 1, the first rigid secondary rod 10 of the driven motion branch chain, the second rigid secondary rod 12, and the first connecting rod 13 form a first parallelogram Structure, the line between the first connecting rod 13 of the driven motion branch chain, the first rigid primary rod 9, the second rigid primary rod 11, the first support member 7 and the axis of the second support member 8 constitutes the first Two parallelogram structures;

The connecting line between the two hole axes on the second side of the moving platform 1 forms a third parallelogram with the third rigid secondary rod 22, the fourth rigid secondary rod 23, and the second connecting rod 24 of an active motion branch chain. structure, the second connecting rod 24 of the active motion branch chain, the third rigid primary rod 20, the fourth rigid primary rod 21, the direct drive rotating motor 18 and the axis of the third support member 19 constitute the first connecting line. Four parallelogram structure;

The connecting line between the two hole axes on the third side of the moving platform 1 forms the fifth parallel with the third rigid secondary rod 22, the fourth rigid secondary rod 23, and the second connecting rod 24 of another active motion branch chain. Quadrilateral structure, the second connecting rod 24 of the active motion branch chain, the third rigid primary rod 20, the fourth rigid primary rod 21, the direct drive rotating motor 18 and the axis of the third support member 19 constitute the connection line Sixth parallelogram structure;

The two parallelogram structures on the three motion branch chains restrict the moving platform 1 to translational motion on the horizontal plane, and have two degrees of freedom. The two-degree-of-freedom moving platform 1 is easy to control, stable in structure, and widely used; in addition , the connection line between the axis of the first support 7 and the second support 8 of the driven motion branch chain, the connection between the direct drive rotating motor 18 of the two active motion branches and the axis of the third support 19 Lines can be extended to form an equilateral triangle.

Described control unit comprises computer 29, motion control card 30, terminal board 31 and direct drive rotary motor servo drive unit 32, computer 29 is connected with motion control card 30, and motion control card 30 is connected with terminal board 31, and terminal board 31 is connected with terminal board 31 respectively. The encoder, the acceleration sensor 3 are connected to the direct drive rotary motor servo drive unit 32, and the direct drive rotary motor servo drive unit 32 is connected to the direct drive rotary motor 18;

The acceleration sensor 3 measures the acceleration signals of the moving platform 1 in two directions on the horizontal plane, and the acceleration signals are input to the motion control card 30 through the terminal board 31 for A/D conversion to obtain digital signals, which are processed by the computer 29 to obtain The feedback signal of moving platform 1 (that is, the displacement information of moving platform 1);

The encoder measures the angular displacement signal that directly drives the rotary motor 18 to rotate. The angular displacement signal is input to the motion control card 30 through the terminal board 31 for pulse counting to obtain a digital signal, and the digital signal is processed by the computer 29 to obtain the direct drive rotary motor 18. output signal;

The computer 29 obtains a control signal according to the feedback signal of the moving platform 1 and the output signal of the direct drive rotary motor, and the control signal is input to the direct drive rotary motor servo drive unit 32 through the motion control card 30 and the terminal board 31 to control the direct drive rotary motor 18 The output to realize the motion control of the moving platform 1.

In the present embodiment, computer 29 selects the desktop computer that CPU is core i7-7700k, memory 8GB, main board is equipped with PCI-e card slot, can insert motion control card; The motion control card (19) that selects is American solid high company The GTS-400-PV-PCI series motion controller produced by the company integrates multi-channel A/D conversion, D/A conversion and code disc counting functions, and has 4 axis resource channels (each axis signal has a Analog output, incremental encoder input, motor control output and alarm reset function), optocoupler isolation, general digital signal input and output each have 16 channels, quadruple frequency incremental auxiliary encoder input 2 channels, A/D There are 8 channels of analog sampling input, and the voltage range of analog input and output is: -10V～+10V.

As shown in Figures 1 to 4, this embodiment also provides a method for controlling a planar two-degree-of-freedom parallel mechanism, which is implemented based on the above-mentioned device, and includes the following steps:

Step 1: The acceleration sensor 3 on the moving platform 1 measures the acceleration signals along the X and Y directions of the moving platform 1 during horizontal plane translational motion, and performs kinematic inverse solution to the acceleration signals to obtain the angular velocity and Angular acceleration component signal;

Step 2: Input the analog signal measured in step 1 to the motion control card 30 through the terminal board 31 to perform A/D conversion to obtain a digital signal, and the computer 29 processes the digital signal, specifically, the computer 29 runs the control algorithm and performs filtering After processing, the feedback signal of the moving platform 1 is obtained;

Step 3, directly drive the encoder of the rotary motor 18 to measure the rotation angle displacement signal of the direct drive rotary motor 18, and the angular displacement signal is input to the motion control card 30 through the terminal board 31 to perform pulse counting to obtain a digital signal, and the digital signal is obtained by the computer 29 Process to obtain the output signal of the direct drive rotary motor 18;

Step 4: The computer compares and analyzes the output signal of the direct drive rotating motor 18 with the feedback signal of the moving platform 1, and compares it with the expected motion and position parameters, and then runs the corresponding control algorithm to obtain the required control Signals, control signals are input to the direct drive rotary motor servo drive unit 32 through the motion control card 30 and the terminal board 31, and the direct drive rotary motor servo unit 32 controls the output of the direct drive rotary motor 18 according to the control signal, so as to control the movement of the braking platform 1 the goal of.

In summary, the present invention designs three kinematic branch chains, one of which is used as a driven kinematic branch chain, and the other two are used as active kinematic branch chains. Intermediate transmission mechanisms such as gear reducer the influence of friction, no backlash problem, simpler and more compact mechanical structure, greatly improving the motion control accuracy and response speed of the mechanism, higher reliability, and easier maintenance Simple; in addition, an acceleration sensor is installed on the moving platform, which can measure the acceleration signals in two directions along the horizontal plane when the moving platform is moving, and there is an encoder inside the direct drive rotating motor, which can measure the angular displacement signal when the directly driving rotating motor rotates. According to the motion parameters measured by the parameters measured by the acceleration sensor and the encoder, the control of the moving platform is realized.

The above is only a preferred embodiment of the patent of the present invention, but the scope of protection of the patent of the present invention is not limited thereto. Equivalent replacements or changes to the technical solutions and their inventive concepts all fall within the scope of protection of the invention patent.

Claims (8)

1. The plane two-degree-of-freedom parallel mechanism control device is characterized in that: the parallel mechanism comprises a parallel mechanism body and a control unit, wherein the parallel mechanism body comprises a movable platform, a static platform, a driven movement branched chain and two driving movement branched chains;

the driven movement branched chain comprises a first support piece, a second support piece, a first rigid primary rod, a second rigid primary rod, a first rigid secondary rod, a second rigid secondary rod and a first connecting rod, wherein the first support piece, the first rigid primary rod and the first rigid secondary rod are sequentially connected, the second support piece, the second rigid primary rod and the second rigid secondary rod are sequentially connected, and the joint between the first rigid primary rod and the first rigid secondary rod is connected with the joint between the second rigid primary rod and the second rigid secondary rod through the first connecting rod;

each active movement branched chain comprises a direct driving rotating motor with an encoder, a third supporting piece, a third rigid primary rod, a fourth rigid primary rod, a third rigid secondary rod, a fourth rigid secondary rod and a second connecting rod, wherein the direct driving rotating motor, the third rigid primary rod and the third rigid secondary rod are sequentially connected, the third supporting piece, the fourth rigid primary rod and the fourth rigid secondary rod are sequentially connected, and the joint between the third rigid primary rod and the third rigid secondary rod is connected with the joint between the fourth rigid primary rod and the fourth rigid secondary rod through the second connecting rod;

the movable platform is in an equilateral triangle shape and is provided with an acceleration sensor, a first side of the movable platform is connected with a first rigid secondary rod and a second rigid secondary rod of a driven movement branched chain, a second side of the movable platform is connected with a third rigid secondary rod and a fourth rigid secondary rod of one driving movement branched chain, and a third side of the movable platform is connected with the third rigid secondary rod and the fourth rigid secondary rod of the other driving movement branched chain;

the control unit is respectively connected with the direct-drive rotating motor and the acceleration sensor;

the encoder is arranged in the direct-drive rotary motor, and the acceleration sensor is arranged at the center of the upper surface of the movable platform;

the static platform comprises a base plate, four supporting feet are arranged at the bottom of the base plate, and a transverse bracket is arranged between every two adjacent supporting feet; the first supporting piece and the second supporting piece of the driven movement branched chain, the direct driving rotating motor of the two driving movement branched chains and the third supporting piece are all fixed on the base plate of the static platform.

2. The planar two-degree-of-freedom parallel mechanism control device of claim 1, wherein: the three sides of the movable platform are respectively provided with two holes, the two holes on the first side of the movable platform are respectively connected with a first rigid secondary rod and a second rigid secondary rod of the driven movement branched chain through a first rotating shaft, the two holes on the second side are respectively connected with a third rigid secondary rod and a fourth rigid secondary rod of one of the driving movement branched chains through a second rotating shaft, and the two holes on the third side are respectively connected with the third rigid secondary rod and the fourth rigid secondary rod of the other driving movement branched chain through a third rotating shaft.

3. The planar two-degree-of-freedom parallel mechanism control device according to claim 2, wherein:

the first support piece is provided with a fourth rotating shaft, the fourth rotating shaft is provided with a first sleeve through a bearing sleeve, one end of the first rigid primary rod is fixed on the first sleeve, the other end of the first rigid primary rod is hinged with one end of the first rigid secondary rod through a fifth rotating shaft, and the fifth rotating shaft is provided with a second sleeve through a bearing sleeve;

a sixth rotating shaft is arranged on the second supporting piece, a third sleeve is arranged on the sixth rotating shaft through a bearing sleeve, one end of the second rigid primary rod is fixed on the third sleeve, the other end of the second rigid primary rod is hinged with one end of the second rigid secondary rod through a seventh rotating shaft, and a fourth sleeve is arranged on the seventh rotating shaft through a bearing sleeve;

the other end of the first rigid secondary rod and the other end of the second rigid secondary rod are hinged with two holes on the first side of the movable platform through a first rotating shaft respectively; the two ends of the first connecting rod are respectively fixed on the second sleeve and the fourth sleeve.

4. The planar two-degree-of-freedom parallel mechanism control device according to claim 2, wherein:

the direct-drive rotary motor is connected with one end of a third rigid primary rod through a flange, the flange is fixed on a rotor of the direct-drive rotary motor, one end of the third rigid primary rod is fixed on the flange, the other end of the third rigid primary rod is hinged with one end of a third rigid secondary rod through an eighth rotating shaft, and the eighth rotating shaft is sleeved with a fifth sleeve through a bearing;

a ninth rotating shaft is arranged on the third supporting piece, a sixth sleeve is arranged on the ninth rotating shaft through a bearing sleeve, one end of the fourth rigid primary rod is fixed on the sixth sleeve, the other end of the fourth rigid primary rod is hinged with one end of the fourth rigid secondary rod through a tenth rotating shaft, and a seventh sleeve is arranged on the tenth rotating shaft through a bearing sleeve;

for one of the active movement branched chains, the other end of the third rigid secondary rod and the other end of the fourth rigid secondary rod are respectively hinged with two holes on the second side of the movable platform through a second rotating shaft; for the other active movement branched chain, the other end of the third rigid secondary rod and the other end of the fourth rigid secondary rod are respectively hinged with two holes on the third side of the movable platform through a second rotating shaft; the two ends of the second connecting rod are respectively fixed on the fifth sleeve and the seventh sleeve.

5. The planar two-degree-of-freedom parallel mechanism control device according to claim 2, wherein:

the first rigid primary rod, the first rigid secondary rod and the first connecting rod form a first composite hinge structure, the second rigid primary rod, the second rigid secondary rod and the first connecting rod form a second composite hinge structure, the third rigid primary rod, the third rigid secondary rod and the second connecting rod form a third composite hinge structure, and the fourth rigid primary rod, the fourth rigid secondary rod and the second connecting rod form a fourth composite hinge structure;

the first rigid primary rod, the second rigid primary rod, the third rigid primary rod and the fourth rigid primary rod have the same length, and the first rigid secondary rod, the second rigid secondary rod, the third rigid secondary rod and the fourth rigid secondary rod have the same length; the distance between the axes of the first composite hinge structure and the second composite hinge structure, the distance between the axes of the third composite hinge structure and the fourth composite hinge structure, the distance between the axes of the first supporting piece and the second supporting piece, the distance between the axes of the direct-drive rotating motor and the third supporting piece and the distance between the axes of two holes on each side of the movable platform are all the same.

6. The planar two-degree-of-freedom parallel mechanism control device according to claim 2, wherein:

the connecting line between the axes of the two holes on the first side of the movable platform, the first rigid secondary rod, the second rigid secondary rod and the first connecting rod of the driven movement branched chain form a first parallelogram structure, and the connecting line between the axes of the first connecting rod, the first rigid primary rod, the second rigid primary rod, the first supporting piece and the second supporting piece of the driven movement branched chain form a second parallelogram structure;

the connecting line between the axes of the two holes on the second side of the movable platform and the connecting line between the second connecting rod, the third rigid primary rod, the fourth rigid primary rod and the fourth rigid primary rod of the active movement branched chain and the axes of the direct driving rotary motor and the third supporting piece form a fourth parallelogram structure;

the connecting line between the axes of the two holes on the third side of the movable platform and the connecting line between the second connecting rod, the third rigid primary rod and the fourth rigid primary rod of the active movement branched chain and the axes of the direct driving rotary motor and the third supporting piece form a fifth parallelogram structure.

7. The planar two-degree-of-freedom parallel mechanism control device of claim 1, wherein: the control unit comprises a computer, a motion control card, a terminal board and a direct-drive rotating motor servo driving unit, wherein the computer is connected with the motion control card, the motion control card integrates the functions of A/D conversion and pulse counting and is connected with the terminal board, the terminal board is respectively connected with an encoder, an acceleration sensor and the direct-drive rotating motor servo driving unit, and the direct-drive rotating motor servo driving unit is connected with the direct-drive rotating motor;

the acceleration sensor measures acceleration signals of the movable platform in two directions on a horizontal plane, the acceleration signals are input into the motion control card through the terminal board to be subjected to A/D conversion to obtain digital signals, and the digital signals are processed by the computer to obtain feedback signals of the movable platform;

the encoder measures an angular displacement signal which directly drives the rotating motor to rotate, the angular displacement signal is input into the motion control card through the terminal board to perform pulse counting to obtain a digital signal, and the digital signal is processed by the computer to obtain an output signal which directly drives the rotating motor;

the computer obtains a control signal according to the feedback signal of the movable platform and the output signal of the direct-drive rotary motor, the control signal is input to the servo drive unit of the direct-drive rotary motor through the motion control card and the terminal board, and the output of the direct-drive rotary motor is controlled to realize the motion control of the movable platform.

8. The control method of the plane two-degree-of-freedom parallel mechanism based on the device of claim 7, which is characterized in that: the method comprises the following steps:

measuring acceleration signals along X, Y directions when the movable platform moves horizontally by an acceleration sensor on the movable platform, and performing kinematic inverse solution on the acceleration signals to obtain angular velocity and angular acceleration component signals of a direct-drive rotating motor;

step two, the analog signal measured in the step one is input into a motion control card through a terminal board to be subjected to A/D conversion to obtain a digital signal, and the digital signal is processed by a computer to obtain a feedback signal of the movable platform;

measuring an encoder of the direct-drive rotary motor to obtain a rotation angle displacement signal of the direct-drive rotary motor, inputting the angle displacement signal into a motion control card through a terminal board to perform pulse counting to obtain a digital signal, and processing the digital signal by a computer to obtain an output signal of the direct-drive rotary motor;

and fourthly, after comparing, processing and analyzing the output signal of the direct-drive rotating motor with the feedback signal of the movable platform by the computer, comparing the output signal with expected movement and position parameters, and then running a corresponding control algorithm to obtain a required control signal, wherein the control signal is input to a direct-drive rotating motor servo driving unit through a movement control card and a terminal board, and the direct-drive rotating motor servo unit controls the output of the direct-drive rotating motor according to the control signal, so that the purpose of controlling the movement of the movable platform is achieved.

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