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Ackermann model mobile robot odometer calibration method

A mobile robot and calibration method technology, applied in the field of Ackerman model mobile robot odometer calibration, can solve the problems of assembly error, reduce the diversity of robot motion forms, low efficiency, etc., so as to eliminate the interference and motion forms of artificial ranging. The effect of diversification and improving calibration efficiency

Active Publication Date: 2020-12-18
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In SLAM technology, the pose estimation of the mobile robot is particularly important. However, due to the assembly error of the mobile robot, the gap between the teeth, and the slippage of the wheels during the movement, the mobile robot often uses the odometer information to estimate the pose. There is a relatively large error, so it is particularly important to calibrate the odometer
[0003] Most of the existing odometer calibration methods are aimed at the two-wheel differential mobile robot driven by two motors. The robot structure is relatively simple, and manual distance measurement is often used when measuring the relevant distance. The accuracy is low, and the robot is often scheduled to run during calibration. Trajectories reduce the diversity of robot motion forms, which are often quite different from the actual motion conditions, and different motion types often produce different errors, which makes the calibration results not very universal and the efficiency is relatively low.
At the same time, the structure of the Ackerman model is relatively complex, which is obviously different from the two-wheel differential mobile robot. Therefore, the calibration method for other models of mobile robots may not be applicable to the robot of this model.

Method used

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  • Ackermann model mobile robot odometer calibration method
  • Ackermann model mobile robot odometer calibration method
  • Ackermann model mobile robot odometer calibration method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] A method for calibrating the odometer of an Ackerman model mobile robot, the operation steps are as follows:

[0041] (1) Obtain the real corner of the mobile robot during motion through the IMU installed on the mobile robot;

[0042] (2) Calculate the motion speed of the mobile robot by the number of pulses per unit time of the wheel encoder, and integrate the speed to obtain the motion distance of the mobile robot within a certain time interval;

[0043] (3) According to the moving distance of the mobile robot and the rotation angle of the mobile robot obtained by the IMU, the estimated displacement of the mobile robot is obtained by using the dead reckoning algorithm;

[0044] (4) Tracking a single characteristic corner point in the environment by lidar, obtaining its distance and angle relative to the mobile robot at the two sampling times, combined with the IMU rotation angle, and using geometric derivation to calculate the real displacement of the mobile robot;

...

Embodiment 2

[0048] This embodiment is basically the same as Embodiment 1, and the special features are as follows:

[0049]In the present embodiment, in the step (3), the steps of obtaining the estimated displacement of the mobile robot are as follows:

[0050] (3-1) Get the motor speed ω m , then the moving linear velocity of the mobile robot body is v c =r·ω m ; where r is the wheel radius of the mobile robot;

[0051] (3-2) Integrate the speed of the mobile robot to obtain the movement distance s in a given time interval;

[0052] (3-3) Take the midpoint of the connection line between the rear wheels of the mobile robot as the reference point O, and move the reference point from A(x, y) to B(x', y') around point O;

[0053] (3-4) According to the dead reckoning algorithm: Where s is the moving distance of the car within a given time, θ 1 ,θ 2 are the attitude angles of the car during the two sampling times;

[0054] (3-5) Calculate the displacement of the mobile robot based on...

Embodiment 3

[0067] This embodiment is basically the same as the above-mentioned embodiment, and the special features are as follows:

[0068] In this example, figure 1 Is the schematic diagram of the mobile robot motion environment. It is required that in this environment, there is only one corner point within the detectable range of the lidar for the lidar to track. figure 2 It is the dynamic model of the Ackerman model mobile robot. The lidar and IMU can be installed on the head and tail of the robot along the central axis of the robot. image 3 It is a schematic diagram of the laser measuring the displacement of the mobile robot. According to the two sampling, the displacement of the mobile robot is estimated. Figure 4 It is a schematic diagram of the dead reckoning of the Ackerman model mobile robot. Using the encoder and IMU information, the pose of the mobile robot at the two sampling times is estimated. Figure 5 It is the data processing flow of the odometer calibration of th...

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Abstract

The invention discloses an Ackermann model mobile robot odometer calibration method, which comprises the following steps: respectively installing a wheel type encoder, a laser radar and an IMU on a mobile robot, obtaining the speed of the mobile robot through the wheel type encoder installed on a motor, and obtaining the movement distance of the robot through integrating the speed; acquiring a rotation angle of the mobile robot within a certain period of time through the IMU; and obtaining the distance and angle of the angular point relative to the mobile robot at different sampling moments through a single angular point in a laser radar tracking environment; and calculating estimated displacement and real displacement of the mobile robot according to the acquired related data, obtaining an error coefficient, and completing odometer calibration of the mobile robot. According to the present invention, the robot odometer calibration is completed by utilizing the high-precision characteristics of the IMU and the laser radar, the pose estimation precision of the robot in the moving process is improved, and the precision of the mobile robot during mapping, positioning and navigation isfurther improved. The method is applied to the technical field of simultaneous positioning and map construction of the mobile robot.

Description

technical field [0001] The invention relates to the field technology of the odometer calibration of a mobile robot, in particular to a method for calibrating the odometer of an Ackerman model mobile robot. Background technique [0002] With the rapid development of computer technology, machine vision, artificial intelligence and other technologies, mobile robots have also been more in-depth research and increasingly widely used. In the field of national defense, drones and unmanned vehicles are used for reconnaissance, intelligence collection and tracking; in the field of logistics, AGV cars have become an important part of the intelligent logistics system. In the service field, various cleaning robots, welcome robots, catering robots, shopping guide robots and medical robots have also been launched one after another, and SLAM technology, one of the supporting technologies, is also developing continuously. In SLAM technology, the pose estimation of the mobile robot is parti...

Claims

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Application Information

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IPC IPC(8): G01C25/00
CPCG01C25/00G01C25/005
Inventor 范文强徐嘉骏辛绍杰
Owner SHANGHAI UNIV
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