CN103240743B - System and method for improving performance of incremental code disc - Google Patents

Abstract

The invention discloses a system and method for improving the performance of an incremental code disc. On the basis of the robot computer system, a single-chip microcomputer system is added to realize performance improvement. The robot computer system is used to control the operation of the robot and use the incremental code disc to detect the current position information of the robot joints. It sends the current position information of the robot joints to the single-chip microcomputer system when the robot finishes working, and from the The single-chip microcomputer system receives the current position information of the robot joint; the single-chip microcomputer system is used to detect the pulse information sent by the incremental code disc after receiving the current position information of the robot joint sent by the robot computer system, and update it according to the pulse information The current position information of the robot joint. The above-mentioned system disclosed by the present invention can accurately obtain the current position of the motor at any time, realizes the absolute counting of the incremental code disc, and can meet the requirements of the manufacturer for the low cost and high performance of the robot system.

Description

System and method for improving performance of incremental code disc

technical field

The invention belongs to the field of robot automation, and in particular relates to a system and method for improving the performance of an incremental code disc.

Background technique

Robot manipulation refers to the movement of the end tool in space through some mechanism. In order to meet the actual production needs, the end tool should move according to the determined trajectory, that is, control the pose of the robot end tool at each moment, which needs to be realized by controlling the accurate position of each joint of the robot at any time. Therefore, it is of great significance to accurately record the position of the motor.

There are many methods for detecting the position of servo motors, among which photoelectric encoders are the most widely used in robot control. Photoelectric code discs are usually divided into absolute code discs and incremental code discs according to the different signals generated by the work. Among them, the motor position signal generated by the absolute code disc is unique, and the position of the motor can be known at any time. The absolute code disc has strong anti-interference characteristics and high reliability, but because its output signal is relatively complex, it brings difficulties to the design of the signal processing circuit. In addition, the cost of the absolute code disc is also high. The incremental code disc outputs quadrature pulses when the motor rotates, and the counting device processes and calculates its position. When the encoder is stationary or the system is powered off, the position information is recorded by the internal memory of the counting device. For servo motors using incremental code discs, when the system is powered off, the motor must not have any vibration, otherwise, the zero position memorized by the counting device will be offset, and this offset can only be confirmed after the wrong production result occurs. You know, this is not allowed to happen in the industrial field.

To sum up, the position information of the absolute code wheel can be read directly at any time, but the cost is high and the hardware circuit is complicated. For the incremental encoder, when the motor restarts after power failure, or the motor rotates abnormally during power failure, such as the brake failure, the actual position of the motor is not easy to know. Therefore, for a servo motor using an incremental encoder, an external system is required to record the position of the motor when the upper computer is powered off, otherwise it would be cumbersome to recalibrate the position of the motor every time it is turned on, and sometimes it is even unfeasible. In view of the wide application of incremental code discs, it is of great significance to overcome the shortcomings of incremental code discs.

Contents of the invention

In view of this, the present invention proposes a system and method for improving the performance of an incremental code disc. The above-mentioned system proposed by the present invention is installed on the basis of the original robot system, and the position of the motor is recorded by the system when the upper computer is powered off, and the absolute counting function of the incremental code disc can be realized.

The performance improvement system for incremental code discs disclosed by the present invention includes:

The robot computer system is used to control the operation of the robot and use the incremental code disc to detect the current position information of the robot joints. It sends the current position information of the robot joints to the single-chip microcomputer system when the robot finishes working, and from the The single-chip microcomputer system receives the current position information of the robot joint;

The single-chip microcomputer system is used to detect the pulse information sent by the incremental code disc after receiving the current position information of the robot joint sent by the robot computer system, and update the current position information of the robot joint according to the pulse information.

The method for improving the performance of an incremental code disc disclosed by the present invention includes:

Step 1, the robot computer system uses the incremental code disc to detect the position information of the robot joints;

Step 2, the robot computer system sends the current position information of the robot joints to the single-chip microcomputer system, and ends the work of the robot;

Step 3. After the single-chip microcomputer system receives the current position information of the robot joints sent by the robot computer system, it detects the pulse information of the incremental code disc;

Step 4, updating the current position information of the robot joints according to the detected pulse information;

Step 5: The robot starts working again, and the computer system of the robot acquires the current position information of the joints of the robot from the single-chip microcomputer system.

The beneficial effect obtained by the present invention is to propose a system and method for recording the position of the motor when the upper computer is powered off:

Advantage 1, the absolute counting function relative to the code disc can be realized, and the robot system does not need to be re-calibrated every time it is powered on;

Advantage 2, adding a single-chip microcomputer system to the robot system, it is convenient and quick to realize the function upgrading of the original system;

Advantage three, low cost, simple structure, high reliability;

Advantage 4, the system has low power consumption and adopts advanced power management scheme. No need to replace the battery, convenient for users;

Advantage 5, wide applicability, for different types of code discs, it can be modified by using the corresponding code disc interface.

Description of drawings

Fig. 1 is a structural block diagram of a robot system in the present invention;

Fig. 2 is a schematic diagram of the working principle of the power management module in the present invention;

Fig. 3 is a schematic diagram of the principle of incremental code disc pulse counting in the present invention;

Fig. 4 is a schematic diagram of the realization principle of the code disc signal processing module in the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

Fig. 1 shows a structural block diagram of a robot system with an incremental code disc performance improving device in the present invention. This robot system comprises as shown in Figure 1: robot 1, robot joint 2, motor 3, motor controller 4, incremental code disc 5, robot computer system 6 and single-chip microcomputer system 7; Described robot computer system 6 and single-chip microcomputer The system 7 together constitutes a device for performance enhancement of incremental code discs.

The single-chip microcomputer system includes: a CPU, a code disc signal processing module 8 , a power management module 9 and a data communication module 10 . Wherein, the robot computer system 6 adjusts the motor 3 at the robot joint 2 to be at the zero position when starting up, and the robot computer system 6 controls the rotation angle and speed of the motor 3 at the robot joint 2 through the motor controller 4 during normal operation, and the incremental code The disk 5 records the relative position of the motor 3 at the robot joint 2 as a feedback signal.

The single-chip microcomputer system 7 preferably uses TI's MSP430G2553 as the CPU, and the code wheel signal processing module 8, the power management module 9 and the data communication module 10 constitute peripheral circuits. The code disc signal processing module 8 is used to detect and record the pulse signal sent by the incremental code disc 5, and calculate and store the relative position information of the corresponding joint according to the detected pulse signal; the power management module 9 Responsible for converting the power supply voltage into the level required by the single-chip system chip, and realizing the switching between the single-chip system 7 between the robot system power supply and the dual power supply of the rechargeable battery; the data communication module 10 is used to realize the single-chip system 7 and the robot computer system 6 Communication.

When the robot system is powered off, the robot computer system 6 transmits the current position information of the motor 3 at the robot joint 2 places to the single-chip microcomputer system 7, and sends a start counting command; 7 Receive the position information at this time, and send the end counting and clear the current position information command.

Fig. 2 shows a schematic diagram of the structure and working principle of the power management module in the present invention. As shown in FIG. 2 , the power management module includes: a charging circuit 11 , a battery part 12 , a photoelectric isolation 13 , and a level conversion chip 14 . Wherein, the charging circuit 11 adopts a dedicated charging module, which is used to charge the battery part 12; the battery part 12 preferably adopts a 1000mAh rechargeable battery, which is used to supply power to the single-chip microcomputer system 7 after the robot computer system 6 is powered off; Photoelectric isolation 13, it is used for the electrical isolation of robot computer system 6 and single-chip microcomputer system 7, guarantees safe and reliable; The supply voltage is converted to the level required by the microcontroller system.

It can be seen that the power management module has two functions. The first is that it can realize dual power supply management, switching between the power supply of the robot system and the power supply of the rechargeable battery. When the microcontroller detects that the robot system is powered on, the robot system supplies power to the microcontroller system and charges the battery; when it detects that the robot system is powered off, the battery supplies power to the microcontroller system. The second is level conversion, which can convert the power supply voltage to the level required by the CPU and chip in the single-chip microcomputer system to ensure the normal operation of the system. In addition, a large-capacity capacitor is installed in the power supply circuit to ensure continuous and stable voltage when the power supply is switched; the battery capacity should be selected to ensure that the robot system can supply enough for the normal operation of the single-chip system during power failure.

Fig. 3 shows a schematic diagram of the pulse counting principle of the incremental code disc in the present invention. As shown in Figure 3, the incremental code disc 5 generates two pulse signals A and B with a phase difference of 90 degrees, wherein the pulse signal A is used to indicate the position change of the motor, and the pulse signal B is used to indicate the position of the motor. turn. Assuming that B is low level when the pulse signal of channel A rises, it means that the motor 3 is rotating forward at this time; on the contrary, if B is high level when the pulse signal of channel A is rising, the motor is reversed at this time. Although there will be systematic errors in this method, such as individual pulses cannot be captured, since the motor has both forward and reverse rotations, there will be no progressive errors in one direction, and there will be no problems in a short time.

Fig. 4 shows a schematic diagram of the implementation principle of the code wheel signal processing module 8 in the present invention. As shown in FIG. 3 , the code wheel signal processing module includes: a pulse detection function module 15 , a pulse recording function module 16 and a position information storage module 17 . Wherein, the pulse detection function module 15 is used to detect the A-way pulse signal of the incremental code disc 5 when the single-chip microcomputer system 7 is powered by the battery part 12, and after detecting the A-way pulse signal, wake up The CPU of the single-chip microcomputer system 7 makes it run at full speed; the pulse recording function module 16 is used to record the two-way A and B orthogonal pulse signals output by the incremental code disc 5 when the single-chip microcomputer system 7 runs at full speed. Described pulse recording function module 16 comprises number signal port 18 and direction signal port 19, and described number signal port 18 is used for capturing the rising edge of A road pulse signal, and record pulse number, and according to the recorded pulse number The number and the number of digits of the incremental code disc 5 are converted into the position information of the motor. Wherein the number of digits of incremental code disc 5 is known by its nameplate, and is stored during programming. For example, there is an N-bit code disc, that is, the number of pulses generated by one rotation is 2 ^N , if the number of pulses recorded by the number signal port 18 is n, then it can be known that the motor rotation angle is . The direction signal port 19 is used to read the level of the B-channel pulse signal at this time, and use it to judge the direction of the motor. Wherein, the pulse detection function module 15 and the pulse recording function module 16 are realized by the IO port of the MSP430G2553 MCU system 7. The position information storage module 17 is used for storing the current position information of the motor, and is realized by the internal memory of the single-chip microcomputer system 7, that is, the MSP430G2553 single-chip microcomputer.

The following describes in detail the operation process of the above-mentioned robot system with the incremental code disc performance improving device.

1) When the robot computer system 6 was working normally, the single-chip microcomputer system 7 was in a low-power dormant state; when the robot computer system 6 finished working, it sent a wake-up signal to the data communication module 10 of the single-chip computer system 7, and transmitted Current position information of robot joint 2.

2) After the robot computer system 6 is powered off, the single-chip microcomputer system 7 switches its power supply, and its power supply is transferred to the battery part 12 by the robot computer system 6, and the single-chip microcomputer system 7 is in a low power consumption state ready to count.

3) Due to abnormal rotation of the motor caused by brake failure or other circumstances, the incremental code disc 5 will output two orthogonal pulse signals of A and B as interrupt signals. When the pulse detection function module 15 of single-chip microcomputer system 7 detects described A, B two-way pulse signal, make it run at full speed, and enter interrupt service subroutine, and then pulse recording function module 16 realizes to A, B two-way orthogonal record of the pulse signal, and constantly refresh the motor position information in the position information storage module 17. In addition, according to whether there is a pulse signal, the single-chip microcomputer system 7 selects a full-speed operation or a low-power operation mode to ensure a longer battery operation.

4) When the single-chip microcomputer system 7 is programmed, the model of the incremental code disc is stored, and the number of digits of the incremental code disc 5 can be known, and then the pulse information is converted into a position change, and the position information of the joint 2 is continuously updated. Due to the limited operating speed of the single-chip microcomputer system 7, in order to ensure the measurement accuracy of the position of the robot joint 2 and the safety of the robot 1, when the relative position recorded by the single-chip microcomputer system 7 exceeds its capability, such as a large number of pulses are lost, the range is exceeded, and the internal program conflicts, etc., When the robot computer system 6 is turned on, it will receive a re-zero instruction from the single-chip microcomputer system 7.

5) When the robot computer system 6 starts working again, the single-chip microcomputer system 7 transmits the position information of the joint 2 to the robot computer system 6 . Thus, the robot computer system 6 can start working directly without recalibration. After the single-chip microcomputer system 7 uploads the relative position information, it is in a dormant state and waits for the command of the robot computer system 6 . At the same time, the single-chip microcomputer system 7 switches the power supply, and the robot robot system 6 supplies power for the single-chip microcomputer system 7, and charges the battery part 12 through the charging circuit 11 .

The above-mentioned system proposed by the present invention makes full use of the counting function of the robot system itself during work, coordinates through serial port communication, and records the position of the motor at different times with the single-chip microcomputer system. The single-chip microcomputer system is used to record the abnormal small rotation of the motor during the power-off period of the robot, and the single-chip microcomputer with a low computing speed can meet the requirements. It is worth emphasizing that this system can fully improve the performance of the system without making any changes to the robot system itself. It has obvious advantages in terms of power consumption and cost, and can effectively meet the needs of low-cost and high-performance products in the robotics field. .

The above-mentioned system disclosed by the present invention has the following advantages: 1) it can be used for different types of code discs, only the data acquisition interface needs to be replaced, and the hardware circuit and software program have high versatility, so the application range is wide and the reliability is high; (2) the system It is aimed at the abnormal rotation of the motor after the robot system is not working, and the requirement for the computing speed of the CPU is not high, and the cost of selecting a single-chip microcomputer is low; (3) The orthogonal pulse counting method adopted will not produce progressive errors.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. A system for improving the performance of an incremental code disc, comprising: a robot computer system, which is used to control the operation of the robot and utilizes the incremental code disc to detect the current position information of the robot joints, when the robot finishes working Send the current position information of the robot joints to the single-chip microcomputer system, and receive the current position information of the robot joints from the single-chip microcomputer system when the robot starts to work; The single-chip microcomputer system is used to detect the pulse information sent by the incremental code disc after receiving the current position information of the robot joint sent by the robot computer system, and update the current position information of the robot joint according to the pulse information. 2. The system according to claim 1, wherein the single-chip microcomputer system includes a CPU, a code disc signal processing module and a data communication module, and the code disc signal processing module is used to detect that the incremental code disc sends The pulse information is calculated and stored as the relative position information of the robot joints according to the pulse information; the data communication module is used to realize the communication between the single-chip microcomputer system and the robot computer system. 3. The system according to claim 2, wherein the single-chip microcomputer system also includes a power management module, which includes a charging circuit, a battery, a photoelectric isolation device and a level shifter; the charging circuit is used for the The battery is charged, and the battery is used to supply power to the single-chip microcomputer system after the robot computer system is powered off; the photoelectric isolation device is used for the electrical isolation of the single-chip computer system and the robot computer system; Or the power supply voltage provided by the battery is converted into the level required by the microcontroller system. 4. The system according to claim 2, wherein the pulse information includes two pulse signals, wherein one pulse signal is used to indicate the position variation of the robot joint, and the other pulse signal is used to indicate the turning direction of the robot joint . 5. The system according to claim 4, wherein the code disc signal processing module includes a pulse detection function module, a pulse recording function module and a position information storage module, wherein the pulse detection function module is used to detect increments The pulse signal sent by the type code disc to represent the position change of the robot joint; the pulse recording function module is used to record two pulse signals, and convert the two pulse signals and the digits of the incremental code disc to obtain the The current position information of the robot joints; the position information storage module is used to store the current position information of the robot joints. 6. The system according to claim 1, characterized in that, when the robot is working normally, the single-chip microcomputer system is in a dormant state; after the robot finishes working, the single-chip microcomputer system runs at full speed. 7. The system according to claim 3, characterized in that, when the robot is working normally, the computer system of the robot supplies power to the single-chip microcomputer system; The power supply of the single-chip microcomputer system. 8. A method for improving the performance of an incremental code disc, comprising: Step 1, the robot computer system uses the incremental code disc to detect the position information of the robot joints; Step 2, the robot computer system sends the current position information of the robot joints to the single-chip microcomputer system, and ends the work of the robot; Step 3. After the single-chip microcomputer system receives the current position information of the robot joints sent by the robot computer system, it detects the pulse information of the incremental code disc; Step 4, updating the current position information of the robot joints according to the detected pulse information; Step 5: The robot starts working again, and the computer system of the robot acquires the current position information of the joints of the robot from the single-chip microcomputer system. 9. The method according to claim 8, wherein the single-chip microcomputer system includes a full-speed operation mode and a low-power consumption operation mode, and after detecting the pulse information of the incremental code disc, it enters the full-speed operation mode, otherwise in low-power run mode. 10. The method according to claim 8, wherein when the current position information detected by the single-chip microcomputer system exceeds its capability, when the robot restarts to work, an instruction to reset the current position information to zero is sent to the robot computer system.