CN210081785U - A motion detection device for a flexible joint robotic arm - Google Patents

Abstract

The utility model discloses a motion detection device for a flexible joint mechanical arm, which comprises a mechanical arm body part and a detection control part. The mechanical arm body part includes a three-segment arm rod and an end effector; Joint connection, the detection and control part includes a high-speed camera and an acceleration sensor. Through the detection of the camera and the acceleration sensor, the computer generates a control signal to drive the robotic arm to move, so as to transport the load to the designated target position. The utility model adopts the air flotation device to support the manipulator body to be in a floating state, which can simulate the space environment; through multi-sensor fusion, the motion of the manipulator in the load state can be accurately detected and controlled.

Description

A motion detection device for a flexible joint robotic arm

technical field

The utility model relates to the field of motion detection and control of an articulated mechanical arm, in particular to a motion detection device of a flexible articulated mechanical arm.

Background technique

With the development of space technology, artificial satellites play an important role in scientific and technological experiments, weather forecasting, regional tracking and navigation, and communications. more and more attention. The space manipulator is a manipulator mounted on a satellite. It can observe and capture stationary or moving targets in space. It mainly completes tasks such as auxiliary docking, target handling, on-orbit construction, photography, and the capture and release of satellites and other targets It can also be used as auxiliary equipment for astronauts' out-of-vehicle activities, and is a key supporting technology for on-orbit maintenance and construction. Therefore, the research on space manipulators is of special significance.

Before the space manipulator is launched with the satellite, it needs a lot of ground tests to ensure its reliability and stability. Therefore, the ground experiment simulation platform of the space manipulator plays a very important role. In the existing research work on space manipulators, most of the devices do not fully eliminate the influence of friction, which leads to inconsistency with the actual microgravity undamped floating state and affects the experimental results. In addition, for the convenience of fabrication and experimentation, most of the experimental devices are replaced by small mechanical arm devices that have been greatly reduced. The replacement devices are quite different from the actual large-size space robotic arms in terms of inertial characteristics and control characteristics. , resulting in the loss of representativeness of the experimental results to a certain extent. Therefore, in the ground research of space manipulators, it is particularly important to create a frictionless microgravity floating environment and use equal or approximately equal scale manipulators.

Utility model content

In order to overcome the shortcomings and deficiencies of the prior art, the utility model provides a motion detection device for a flexible joint mechanical arm. The microgravity environment of the simulated space manipulator is fully considered, and the motion detection and precise control of the manipulator under load are realized through multi-sensor fusion.

The utility model adopts the following technical solutions:

A motion detection device for a flexible joint manipulator, comprising a manipulator body part and a detection control part;

The body part of the mechanical arm includes a three-segment arm rod and an end effector. The three-segment arm rod is an upper arm, a forearm and a wrist. One end of the upper arm is connected to a shoulder joint turntable through a shoulder joint, and the shoulder joint turntable is fixed on the shoulder joint. On the test bench, the other end of the upper arm is connected to one end of the forearm through the elbow joint, the other end of the forearm is connected to one end of the wrist through the wrist joint, and the other end of the wrist is installed with the end effector through the rotating joint, and the end effector is installed at the other end of the wrist. The elbow joint and the wrist joint are fixed on the experimental bench through the joint support frame, and the joint support frame is provided with an air flotation device, and the air flotation device is connected with the pneumatic circuit to realize the arm rod working in a floating motion state;

The detection and control part includes a high-speed camera, an acceleration sensor, a charge amplifier, a visual marker, a motion control card and a computer, the computer is connected to the motion control card, the charge amplifier is connected to the motion control card, and the acceleration sensor is arranged on the The middle position of the arm rod, the acceleration sensor detects the vibration signal of the arm rod, inputs the charge amplifier, and enters the computer through the motion control card. At the top of the elbow joint, the visual landmark is within the field of view of the high-speed camera, and the high-speed camera captures an image containing the visual landmark and inputs it to the computer;

The detection and control part also includes a servo motor driver and a direct-drive rotary motor driver. The computer obtains control signals according to the signals detected by the high-speed camera and the acceleration sensor, and outputs the control signals to the direct-drive rotary motor driver, the servo motor driver and the pneumatic circuit respectively. , drive the end effector, arm rod and joint support frame to move, and further control the robotic arm to reach the target position.

The shoulder joint, the elbow joint and the wrist joint have the same structure, and are composed of a DC servo motor, a harmonic reducer and a connecting flange.

The air flotation device is composed of three air flotation pads.

The high-speed camera is installed above the center line in the length direction of the experimental platform through the camera bracket, and is used to detect and identify the position information of the three joints of the arm rod.

The pneumatic circuit includes an air pump, a pneumatic triple piece, a two-position three-way valve, a three-way pipe joint and a four-way pipe joint connected in sequence, and also includes an on-off valve drive circuit connected with the two-position three-way valve. The on-off valve drives the The circuit is connected with the motion control card.

The rotary joint connected to the end effector includes a direct drive rotary motor connected to a direct drive rotary motor driver.

The end effector is a four-finger jaw.

The joint support frame includes an elbow joint support frame and a wrist joint support frame, and the elbow joint support frame and the wrist joint support frame have different heights.

The beneficial effects of the present utility model:

(1) The utility model utilizes the air film formed by spraying pressurized gas from the air flotation pad to support the manipulator body, which avoids its direct contact with the experimental bench, and makes the system in a frictionless suspension state, thereby better simulating the unobstructed space Floating state;

(2) The present utility model detects and controls the motion information of the manipulator by combining the visual sensor and the acceleration sensor, and detects and controls the motion of the manipulator during the load handling process through multi-sensor fusion, which improves the accuracy;

(3) The shoulder joints, elbow joints and wrist joints of the space manipulator in the utility model all adopt the flexible joints of the harmonic reducer, the harmonic transmission structure is compact, the volume is small, the weight is light, the transmission ratio is large, the bearing capacity is large, and the transmission accuracy is high. High, smooth motion, fast and accurate dynamic response;

(4) The utility model adds a rotating joint at the connection between the wrist and the end effector. When the end effector clamps the target load, it can be adjusted to control the end effector to rotate to the optimal clamping posture, which can improve the accuracy of the target object. The success rate and firmness of gripping.

(5) The utility model can simulate and realize the precise control of the space manipulator to carry the load to the target position and other related operation tasks, and provides a reference scheme for each module such as sensing, drive, motion planning, control, etc., which can be used as the space manipulator. The ground simulation experiment platform provides a reference for the research and application of space manipulator related fields.

(6) Three harmonic flexible joints are used in the robotic arm of the present invention, and the device can also be applied to the research on the flexible motion characteristics of the flexible joint robotic arm under load.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the utility model.

FIG. 2 is a front view of the apparatus of FIG. 1 .

FIG. 3 is a top view of the apparatus of FIG. 1 .

FIG. 4 is a schematic structural diagram of the utility model.

Figure 5 is an exploded schematic diagram of the elbow joint structure.

Detailed ways

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

Example

As shown in FIG. 1-FIG. 4, this embodiment provides a motion detection device for a flexible joint robotic arm based on vision and acceleration sensors, the device includes a robotic arm body and a detection control unit;

The dotted line connection in Figure 1 indicates the connection between the various devices, the direction arrow indicates the transmission direction of the detection and control signal flow, and only one of the sensor and driver connections is selected for illustration;

The body of the robotic arm includes three sections of arm rods, an upper arm 5, a forearm 8 and a wrist 12, and an end effector 15. The upper arm is mounted on the shoulder joint turntable 2 on the experimental bench 1 through the shoulder joint, and the forearm passes through the elbow joint 6. It is connected with the upper arm, the wrist is connected with the forearm through the wrist joint, and the end effector is connected with the wrist through the rotating joint 13 .

The three flexible joints of the shoulder joint, the elbow joint and the wrist joint are mainly composed of a servo motor, a harmonic reducer and a connecting flange, and the rotating joint connecting the end effector is composed of a direct drive rotating motor and a mounting flange.

The harmonic reducer used in the flexible joint of the manipulator relies on the continuous elastic deformation of the flexible wheel to transmit torque and motion. The contact method between the flexible wheel and the steel wheel is surface contact, and the number of teeth meshing at the same time is large, so the bearing capacity is relatively high. High, the tooth surface wears evenly, and the backlash of the flex wheel and the steel wheel changes with the load. When the load of the flex wheel is high, it can achieve high-precision meshing without backlash, with high transmission precision and high transmission efficiency. , The hysteresis is small and the transmission is stable.

The structure of the three flexible joints is the same. Take the elbow joint at the connection between the upper arm and the forearm as an example. The exploded diagram of the elbow joint structure is shown in Figure 5. The servo motor 33 is connected with the keyway of the harmonic reducer 35 through a flat key. The locking screw is locked, and is fastened with bolts through the connecting flange 34 to form a joint assembly. One end of the joint assembly is connected and fastened with bolts through the connecting flange and the joint mounting hole 32 on the arm joint boss, and the other end of the joint assembly is connected by bolts. The upper output flange of the harmonic reducer and the mounting hole in the middle of the end of the arm are fastened with bolts. The upper and lower ends of the two arm joints are respectively equipped with a joint upper end cover 36 and a joint lower end cover 31. It is useful to paste on the joint upper end cover Visual markers for high-speed camera recognition4.

An acceleration sensor 9 is arranged at the middle position of each arm rod, which is used to identify the acceleration motion information of the three-section arm rod. The elbow joint is fixed on the experimental bench through the elbow joint support frame 7, and the wrist joint is fixed on the experimental bench through the wrist joint support frame. 11. It is fixed on the test bench. Three air-floating pads are installed at the bottom of the two joints. The three air-floating pads are connected to the pneumatic circuit. The air-floating pads are inflated to make the robot arm float on the marble surface of the test bench.

The pneumatic circuit is used to continuously supply air to the air flotation pads at the bottom of the two joint support frames. The pneumatic circuit consists of an air pump 25, a pneumatic triple piece 26, an on-off valve drive circuit 27, a two-position three-way valve 28, and a three-way pipe joint 29. , four-way pipe joint 30, the air pump and pneumatic triplet are connected in sequence, and connected to the input port of the two-position three-way valve, the on-off of the air circuit is controlled by the switch valve drive circuit, and the output port of the two-position three-way valve Connect one port of a three-way pipe joint as the input, the other two ports of the three-way pipe joint are connected to one port of a four-way pipe joint, and the other three ports of the two four-way pipe joints are connected with the elbow joint support frame in turn. , The three air-floating pads at the bottom of the wrist joint support frame are connected, and the pressurized gas provided by the pneumatic circuit forms a thin pressure air film between the bottom of the air-floating pad and the marble surface through the internal passage of the air-floating pad, so that the mechanical arm In a frictionless suspension state, simulating an undamped floating environment in space;

The detection control part includes a computer 24 , a motion control card 23 , a charge amplifier 22 , a servo motor driver 21 , a direct drive rotary motor driver 20 , and an on-off valve drive circuit 27 .

The high-speed camera 19 is installed in the middle of the length direction of the experimental platform 1 through the camera installation truss 17. The camera installation plate 18 is installed in the middle of the cross bar of the camera installation truss, and the high-speed camera 19 is installed on the cross bar of the truss through the installation plate. The selection of the camera and lens of the high-speed camera, as well as the setting of the installation position, etc., ensure that the entire experimental bench is within the field of view of the high-speed camera; the middle of the segment arm;

The computer is respectively connected with the charge amplifier, the servo motor driver, the direct drive rotary motor driver and the switch valve drive circuit through the motion control card, the charge amplifier is connected with the acceleration sensors on the three arm rods, and the switch valve drives The circuit and the two-position three-way valve are connected in the pneumatic circuit, the servo motor driver is connected with the servo motors at the three flexible joints, and the direct-drive rotary motor driver is connected with the direct-drive rotary motor at the rotary joints.

The working process of the utility model:

Step 1: Input the load handling target position information in the computer, detect the positions of the visual markers on the three flexible joints of the robotic arm through a high-speed camera, and extract the relative position information between the robotic arm and the target position through the image processing algorithm in the computer;

Step 2: The computer preliminarily plans the control signals required by each arm and the joint through the algorithm, and transmits it to the servo motor driver through the motion control card to drive the rotation of the servo motor, so that the mechanical arm moves in the direction of the specified target position;

Step 3: The acceleration sensor detects the acceleration motion information of each manipulator rod in real time, the encoder built in the servo motor detects the rotation information of the motor in real time, and the high-speed camera detects the relative position change of each flexible joint of the manipulator in real time, and all three kinds of motion information are transmitted. to a computer;

Step 4: According to the obtained signals of the acceleration sensor, the encoder and the high-speed camera, the computer uses the corresponding motion control algorithm to solve the corrected motion control signal by fusing the multi-sensor information, and further feedbacks and controls the rotation of the joint servo motor;

Step 5: By fusing multi-sensor information and real-time position information and motion information feedback, the control signal is continuously modified to drive the movement of the robotic arm, and finally the end effector can accurately transport the load to the target position, and complete the precise transport task of the robotic arm to the load. .

In this embodiment, the geometric dimensions of the experimental bench 1 are 3180mm long x 2580mm wide x 800mm high, and the base of the experimental bench is assembled from three aluminum profiles with lengths of 1500mm, 1200mm, and 800mm. It is made of two 1200mm aluminum profiles in the width direction. Each joint of the profiles is fixed by angle iron; the pedestal has two layers of support, and the top is installed with a metal plate. The metal plate consists of two pieces of size: The 2580mm×1590mm stainless steel plates are spliced together. The edge of the metal plate is provided with a rib with a height of 100mm to prevent the mechanical arm from slipping. Multiple marble plates are laid flat on the metal plate to form a flat surface, and the gaps between the marble plates are sealed by sealing materials. .

The materials of the upper arm 5, the forearm 8, and the wrist 12 are the same, and they are all 7075-T7651 aluminum alloys commonly used in spacecraft, with a density of ρ=2820kg·m ^-3 . The wall metal cylinder has a size of 150mm in outer diameter and 15mm in wall thickness, and the lengths of the arms are 1000mm long for the upper arm, 800mm long for the forearm, and 500mm long for the wrist.

The servo motors 33 at the three flexible joints of shoulder joint 3, elbow joint 6 and wrist joint 10 are all servo motors produced by Yaskawa Servo Motor Co., Ltd., and the harmonic reducers 35 at the flexible joints are selected from Hamernaco (Shanghai) Co., Ltd. ) Harmonic reducer produced by ) Trading Co., Ltd., and the servo motor driver used by the three joint servo motors are also products of Yaskawa Servo Motor Co., Ltd. The specific combinations are:

The shoulder joint selects Yaskawa SGM7A-15AFA61 servo motor, with a rated output power of 1.5kW; the supporting servo drive model is SGD7S-120A30A002, and the maximum applicable motor capacity is 1.5kW; the harmonic reducer selection model is CSG-45-100 -LW, the reduction ratio is 1:100;

Yaskawa SGM7A-04AFA61 servo motor is selected for the elbow joint, with a rated output power of 400W; the supporting servo driver is SGD7S-2R8A30A002, and the maximum applicable motor capacity is 0.4kW; the harmonic reducer is selected as CSG-25-100- LW, the reduction ratio is 1:100;

The wrist joint uses Yaskawa SGM7A-01AFA61 servo motor with a rated output power of 100W; the supporting servo driver is SGD7S-R90A30A002, and the maximum applicable motor capacity is 0.1kW; the harmonic reducer is selected as CSG-17-100- LW, the reduction ratio is 1:100.

The direct drive rotary motor 14 at the end effector rotating joint 13 is the direct drive rotary motor model ADR110-A75 produced by Singapore Jacobs, with a rated torque of 1.9Nm; the supporting direct drive rotary motor driver is selected The servo unit produced by Yaskawa Servo Motor Co., Ltd. is SGDV-2R8A; the end effector 15 is the PZV series four-finger gripper of SCHUNK, Germany; the load 16 is a square iron block load with a geometric size of 56mm×56mm×70mm , the load mass is about 1.7kg.

The height of the elbow joint support frame 7 is 189mm, the height of the wrist joint support frame 11 is 336mm, and three air-floating pads of the model AL-60-HD+G produced by the German Aerolas Company are installed at the bottom of both, and the working surface diameter is 60mm , the recommended maximum load is 800N, and the three air-floating pads can support a maximum load of 2400N, which is enough to support the robotic arm joint.

The acceleration sensor 9 is a piezoelectric three-way acceleration sensor of model 8688A10 produced by Kistler Company of Germany, with an acceleration detection range of ±10 g, a sensitivity of 500 mV/g, and a frequency response of 0.5 to 5000 Hz.

The height of the high-speed camera installation truss 17 is 2000mm, and it is installed at the midpoint of the length direction of the test bench; the high-speed camera 19 is a high-speed camera with the model FASTCAM-SA2 from Photron Corporation of Japan, which is equipped with a high-level fusion of ultra-high resolution The latest cutting-edge C-MOS image sensor with high speed, high speed, high definition and high sensitivity, the shooting frequency can reach 1080 frames per second under 2048×2048 pixels, AC power supply voltage 100V～240V, weight 6.9kg, choose Ricoh Japan The company's lens, the model is FL-CC0814-2M, the focal length is 8mm, the size is Ф33.5mm × 28.2mm, the mass is 63g, and the entire test bench is guaranteed to be within the field of view of the high-speed camera.

The charge amplifier 22 selects the YE5850 type charge amplifier of Jiangsu Lianneng Electronics Co., Ltd.; the motion control card 23 selects the DMC-2x00 digital motion controller produced by the American GALIL company, which provides a standard PCI bus interface; the CPU model selected for the computer 24 is core76650U2. 2GHz, memory 4G, there is a PCI-e slot in the motherboard, which can install a motion control card 23.

The air pump 25 selects an air compressor with a model of FB750D0-30A65 produced by Shanghai Jaguar Compressor Manufacturing Co., Ltd., the input power is 2.4kW, the rotational speed is 1380rpm, and the rated volume flow rate is 204L/min; the pneumatic triplet 26 is composed of an air filter ( Model AF30-03), pressure reducing valve (model AR25-03) and oil mist separator (model AFM30-03) are assembled together with a pressure gauge (model: G36-10-01), Produced by Japan SMC Pneumatic Company; two-position three-way valve 28 is a three-way control valve with model VPA342-01A-F, produced by Japan SMC Pneumatic Company; a three-way pipe joint 29 and two four-way pipes in the pneumatic circuit The joint 30 is assembled by using the KB series piping components produced by Japan SMC Pneumatic Company, that is, assembled by selecting 1 KBP plug, 1 KBH internal joint, and 3 KBV elbow components; on-off valve drive circuit 27 Please refer to the utility model patent with the Chinese patent number 200810198032.1 and the title of “Plunger Type Double Rod Air-hydraulic Cylinder and Air-hydraulic Joint Control Position and Speed Servo Control Device”, in which the on-off valve drive circuit 27 is described. illustrate.

The above-mentioned embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited by the described examples, and any other changes, modifications, Substitution, combination, and simplification should all be equivalent substitution methods, which are all included in the protection scope of the present invention.

Claims (8)

1. A motion detection device of a flexible joint mechanical arm is characterized by comprising a mechanical arm body part and a detection control part;

the robot arm comprises a robot arm body part and a robot arm body part, wherein the robot arm body part comprises three sections of arm rods and a tail end effector, the three sections of arm rods are respectively an upper arm, a forearm and a wrist, one end of the upper arm is connected with a shoulder joint rotary table through a shoulder joint, the shoulder joint rotary table is fixed on an experiment table, the other end of the upper arm is connected with one end of the forearm through an elbow joint, the other end of the forearm is connected with one end of the wrist through a wrist joint, the other end of the wrist is provided with the tail end effector through a rotary joint, the elbow joint and the wrist joint are fixed on the experiment table through a joint support frame, the joint support frame is provided with an air floating device, and the;

the detection control part comprises a high-speed camera, an acceleration sensor, a charge amplifier, a visual marker, a motion control card and a computer, wherein the computer is connected with the motion control card, the charge amplifier is connected with the motion control card, the acceleration sensor is arranged in the middle of an arm rod, the acceleration sensor detects a vibration signal of the arm rod, inputs the vibration signal into the charge amplifier and inputs the vibration signal into the computer through the motion control card, the high-speed camera is arranged above the experiment table, the visual marker is arranged at the top ends of a shoulder joint, a wrist joint and an elbow joint and is in the visual field range of the high-speed camera, and the high-speed camera shoots an image containing the visual marker and inputs the image into the computer;

the detection control part also comprises a servo motor driver and a direct drive rotating motor driver, the computer obtains control signals according to signals detected by the high-speed camera and the acceleration sensor, and the control signals are respectively output to the direct drive rotating motor driver, the servo motor driver and the pneumatic circuit to drive the tail end effector, the arm rod and the joint support frame to move, so that the mechanical arm is further controlled to reach a target position.

2. The device for detecting the motion of a flexible joint mechanical arm according to claim 1, wherein the shoulder joint, the elbow joint and the wrist joint have the same structure and are all composed of a direct current servo motor, a harmonic reducer and a connecting flange.

3. The apparatus as claimed in claim 1, wherein the air-floating means is composed of three air-floating pads.

4. The device for detecting the movement of a flexible joint mechanical arm according to claim 1, wherein the high-speed camera is mounted above a midline in the length direction of the laboratory table through a camera support and is used for detecting and identifying the position information of three joints of the arm.

5. The device as claimed in claim 1, wherein the pneumatic circuit comprises an air pump, a pneumatic triplet, a two-position three-way valve, a three-way pipe joint, a four-way pipe joint, and a switching valve driving circuit connected to the two-position three-way valve, and the switching valve driving circuit is connected to the motion control card.

6. The motion detection apparatus of a flexible joint robot arm of claim 1, wherein the revolute joint coupled to the end effector comprises a direct drive rotary motor coupled to a direct drive rotary motor driver.

7. The motion detection apparatus of a flexible joint robot arm as claimed in claim 1, wherein the end effector is a four finger gripper.

8. The device of claim 1, wherein the joint support comprises an elbow support and a wrist support, and the elbow support and the wrist support have different heights.

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