CN109910061B

CN109910061B - Separated magnetic double encoder

Info

Publication number: CN109910061B
Application number: CN201910188291.4A
Authority: CN
Inventors: 梁正
Original assignee: Beijing Kingkong Technology Co ltd
Current assignee: Beijing Kingkong Technology Co ltd
Priority date: 2019-03-13
Filing date: 2019-03-13
Publication date: 2021-03-09
Anticipated expiration: 2039-03-13
Also published as: CN109910061A

Abstract

The separated magnetic double encoder uses two groups of separated magnetic sensitive elements to respectively measure magnetic field information on the magnetic rings, delivers the magnetic field information to a subsequent processing circuit for calculation to obtain the angular positions of the two magnetic rings, can calculate the theoretical and measured difference values of the two encoders under a certain ratio to calculate the external torque, and finally interacts with an upper computer through a group of communication lines, so that the physical space structure and the circuit distribution structure of the double encoder are simplified, a better double encoder system is obtained, and a better design is provided for the structure and the control of a robot.

Description

Separated magnetic double encoder

Technical Field

The invention relates to a device for measuring position and torque, in particular to an encoder device for measuring rotation.

Background

While the application field of robots is increasing, cooperative robots are being used in more light industrial production as automated labor for performing cooperative work with humans. The new application field also provides higher requirement indexes for the cooperative robot, namely the cooperative robot needs low professional technical requirements and high safety when cooperating with people.

The practice of easy operability means that the robot does not rely on complicated programming to give orders, and the robot can teach the mechanical arm through the form of dragging, and the process of teaching requires the robot to have extremely sensitive perception ability to the dragging of external force. Meanwhile, high safety is realized when the robot collides with the outside, the robot is ensured to stop immediately and cannot continue to work to select destructive injury to human bodies or other external objects, and the high perception capability of the robot to the external unpredictable force is also required.

It can be seen that the biggest difference between a cooperative robot and a conventional robot is that it needs to possess sensitive sensing capability for dynamic and static external force. The motion of each degree of freedom of the cooperative robot is generated by an actuator at each joint of the cooperative robot, and the actuator is an integrated structure integrating core elements such as a motor, an encoder, a speed reducer and the like.

External force applied to the robot in the space can directly or indirectly act on the joint actuator, and for example, the six joints of the six-axis robot can sense the force from six degrees of freedom in the space. The external force sensing capability of the robot is actually required to be possessed by the actuator.

However, if the actuator is used as a force output device to sense external force, a special design in structure and algorithm is required, and the existing solutions are: the method comprises the following steps of current calculation, torque sensor calculation, strain gauge calculation and dual encoder calculation, wherein the following advantages and disadvantages of the schemes are as follows:

and (3) current calculation: when the motor output is disturbed by an external force, the locked-rotor current of the motor increases, and the torque is calculated from the current increment without modifying the structure, but with low accuracy.

Torque sensor calculation: the torque sensor is additionally arranged at the output end of the actuator, so that the cost is high and the algorithm difficulty is high.

And (3) strain gauge calculation: a plurality of groups of strain gauges are attached to the harmonic flexspline to measure torque, the structure is extremely complex, and the calibration difficulty is high.

Dual encoder calculation: and a high-resolution encoder is additionally arranged to measure the change of the position of the output end for calculating the torque, so that the cost is low and the precision is high.

The dual-encoder strategy has more excellent cost and precision in sensing the external torque, namely, the dual-encoder strategy means that two encoders are arranged in the actuator, and the required arrangement space is further increased. For the robot, the compact structure and the excellent external force perception sensitivity are important design of the cooperative robot at present or in the future.

Disclosure of Invention

The invention designs a double-encoder structure based on a separated magnetic encoder. The design integrates the two separated magnetic encoders, further reduces the space occupation and cost of the double encoders, and reduces the complexity of the communication system of the actuator.

The separated magnetic encoder measures the magnetic field generated by the measured magnetizing device by a plurality of magnetic sensitive elements distributed in the space of the encoder body, and then delivers the measured data to a subsequent processing circuit to calculate the relative position of the measured magnetizing device and the encoder body in the space. The use of a separate measurement scheme may make hollowing of the encoder possible.

The invention discloses an encoder structure based on the principle of a separated magnetic encoder, and simultaneously, the two sides of a PCB are used for distributing magnetic sensitive elements of two separated magnetic encoders on two sides of the PCB respectively, namely, the front axial space of the PCB and the back axial space of the PCB are used in the axial space.

Meanwhile, to measure the rotation position data of the two shafts, two magnetic rings are required to be fixedly installed with each shaft respectively, when the shafts rotate, the magnetic rings rotate together, and the two groups of magnetic sensitive elements in one circle can measure the corresponding magnetic field data respectively and deliver the measured magnetic field data for subsequent processing.

In the aspect of data processing, the magnetic sensitive elements on two sides are collected and processed in a single chip microcomputer, so that the data processing structure is simplified. After the rotation ratio of the two encoders is configured, the invention can directly carry out theoretical calculation to obtain the current external torque for output.

In terms of communication, when a dual-encoder structure of the original two encoders is used, as shown in fig. 1, a driver needs to communicate with the encoder 1 and the encoder 2 respectively to obtain an angular position of each encoder, and then the external torque is obtained after calculation. The invention can be seen in fig. 2, the driver communicates with the encoder directly through a set of communication paths, which can transmit a plurality of data according to the difference of communication instructions: for example, the position data of the two encoders and the calculated external torque are respectively obtained, so that the number of layout lines in space is saved, and the external torque data is more conveniently and directly provided.

Drawings

Fig. 1 is a communication diagram of a structure composed of two encoders and a driver.

FIG. 2 is a communication diagram of the split magnetic dual encoder and drive of the present invention.

FIG. 3 is a cross-sectional view of a split magnetic dual encoder with radially disposed magnetic rings in accordance with the present invention.

FIG. 4 is a cross-sectional view of a split magnetic dual encoder with the magnetic ring axially disposed in accordance with the present invention.

Detailed Description

The invention relates to a separated magnetic double encoder, which is provided with two groups of measured devices of the encoder and an information acquisition and processing unit device, namely, the separated magnetic double encoder consists of two measured devices (magnetic rings) of the encoder and an encoder body, and the magnetic rings can be arranged at the axial opposite position or the radial opposite position of the encoder body.

As shown in fig. 3, the left magnetic sensor space 2 and the right magnetic sensor space 3 are installed on two sides of the PCB 1, these three parts and other circuits and structural elements on the PCB constitute the encoder body, and the magnetic ring 4 and the magnetic ring 5 are located inside the encoder body at radial opposite positions, or outside the encoder body at radial opposite positions.

After the magnetic ring 4 and the magnetic ring 5 are respectively connected to the corresponding shafts, when the magnetic ring 4 rotates, the plurality of magnetic sensitive elements in the spatial position 2 of the magnetic sensitive elements acquire the radial magnetic field changed when the magnetic ring 4 rotates, and then the data are sent to a subsequent processing circuit of the encoder body; when the magnetic ring 5 rotates, the radial magnetic field around the magnetic ring can be changed, and the changes can be collected by a plurality of magnetic sensitive elements in the spatial position 3 of the magnetic sensitive elements and sent to a subsequent processing circuit, and finally, calculation is carried out in a single chip microcomputer.

As shown in fig. 4, the left magnetic sensor spatial position 2 and the right magnetic third element spatial position 3 are installed on two sides of the PCB board 1, and these three parts are the same as those shown in fig. 3, and together with the other elements on the PCB board, form the encoder body, but different from these two sides, that is, the magnetic ring 4 and the magnetic ring 5 are located on the opposite axial positions of the encoder body.

After the magnetic ring 4 and the magnetic ring 5 are respectively connected to the corresponding shafts, when the magnetic ring 4 rotates, the magnetic field information in the space close to one side of the encoder body can be changed, and the plurality of magnetic sensitive elements in the space position 2 of the magnetic sensitive elements can measure the information and send the analog information to a subsequent processing circuit; when the magnetic ring 5 rotates, the magnetic field information in the space close to one side of the encoder body can be changed, the magnetic sensitive elements in the spatial position 3 of the third magnetic element can measure the magnetic field information, and the analog information is sent to a subsequent processing circuit and finally delivered to the same single chip microcomputer for processing.

The magnetic sensitive elements in the space of the magnetic sensitive elements in fig. 3 and 4 are required by a separated magnetic encoder, a plurality of magnetic sensitive elements are distributed in the space for measuring the magnetic field, and the specific circumferential distribution of the elements is determined according to the requirement of a subsequent algorithm.

The magnetic sensitive elements on each side of the PCB 1 belong to a group respectively, the magnetic sensitive elements are circumferentially distributed on the surface of the PCB, and the intervals of the magnetic sensitive elements are selected by a subsequent algorithm so as to calculate angle data in a matching mode. The structure can be matched with the magnetic ring for measurement, and the encoder can be in an aerial structure, so that more flexible structural application is obtained. The data collected by these magnetic sensitive elements will be delivered to the subsequent processing circuits, such as MUX, op-amp, ADC, etc., which are all finally calculated in a single chip, i.e. the single chip can calculate the current angle data of two encoders at the same time.

When the encoder communicates, as shown in the topology of fig. 2, the encoder may receive or transmit information to the upper control system directly through a set of communication circuits.

Meanwhile, the double-encoder system can directly output theoretical torque parameters, and the theoretical angle ratio of the two encoders at the moment needs to be configured in the upper computer or the FLASH thereof in the initial state. When the input side encoder rotates 100 times as in the control of the cooperative robot actuator, the output side encoder rotates 1 time, and by the ratio, the angle data of the input side encoder can be obtained through measurement, and then the theoretical output side encoder angle is calculated, so that the theoretical output side encoder angle is compared with the output side encoder angle obtained through measurement, and a difference value is obtained, and the difference value can be proportionally corresponding to the external stress of the cooperative robot actuator. The driver can obtain the data through the communication bus, and then the driver can obtain more accurate external stress data by combining with the current measurement of the driver.

This two encoder systems of disconnect-type magnetism, disconnect-type subsection have obtained hollow structure, make the system possess more excellent structure overall arrangement, and its two encoder systems had both reduced the occupation space who uses, had retrencied communication system again, and the promotion that can be very big uses the performance and the design of two encoder structures.

Claims

1. The separated magnetic double encoder is characterized by comprising two groups of separated magnetic sensitive elements, corresponding magnetic rings and a processing circuit chip, wherein the two groups of separated magnetic sensitive elements and the corresponding magnetic rings are arranged, the processing circuit chip is used for measuring two groups of relative positions of the magnetic rings and the encoder body in space, the two groups of magnetic sensitive elements are respectively distributed on two sides of a PCB, the encoder body is formed by the two groups of magnetic sensitive elements, a circuit and a structural element on the encoder PCB, the separated magnetic sensitive elements of each group are distributed on the PCB in a circumferential mode, distribution intervals are selected by a subsequent algorithm to be matched with the subsequent algorithm to calculate angle data, the ratio of the two groups of angle data is.

2. The split magnetic dual encoder as recited in claim 1, wherein the magnetic ring is mounted axially opposite or radially opposite the encoder body, respectively.

3. The split-type magnetic dual encoder as claimed in claim 1, wherein the data measured by the two sets of split-type magnetic sensitive elements are processed by a single-chip microcomputer.

4. The split magnetic dual encoder according to claim 1, wherein the parameter configuration and the angle data output of both encoders are communicated to the upper computer by a set of communication lines.