阅读说明：本技术 一种基于imu和码盘融合的车辆定位方法 (Vehicle positioning method based on IMU and coded disc fusion ) 是由 许文渊 祝露峰 任卓恒 何韵 邓盛兰 杨芬 许天宏 于 2019-12-25 设计创作，主要内容包括：本发明涉及车辆、系统定位技术领域,具体公开了一种基于IMU和码盘融合的车辆定位方法,包括如下步骤,包括如下步骤,步骤1,启动系统；步骤2,获取码盘数据,计算当前位置和航向角θ；步骤3,获取IMU数据计算当前航向角；步骤4,以码盘的x,y坐标和IMU的航向角为基准,进行位置更新。本发明使用码盘和IMU相结合的方法来组成定位系统,计算过程简单,避免繁琐的计算,相较于视觉里程计方法,计算效率得到提高,达到实时性的要求。(The invention relates to the technical field of vehicle and system positioning, and particularly discloses a vehicle positioning method based on IMU and coded disc fusion, which comprises the following steps of 1, starting a system; step 2, code disc data are obtained, and the current position and the course angle theta are calculated; step 3, obtaining IMU data and calculating a current course angle; and 4, updating the position by taking the x and y coordinates of the code disc and the course angle of the IMU as the reference. The positioning system is formed by combining the coded disc and the IMU, the calculation process is simple, complicated calculation is avoided, the calculation efficiency is improved compared with a visual odometer method, and the real-time requirement is met.)

1. A vehicle positioning method based on IMU and code disc fusion is characterized in that: comprises the following steps of (a) carrying out,

step 1, starting a system;

step 2, code disc data are obtained, and the current position and the course angle theta are calculated;

step 3, obtaining IMU data and calculating a current course angle;

and 4, updating the position by taking the x and y coordinates of the code disc and the course angle of the IMU as the reference.

2. The IMU and codewheel fusion based vehicle alignment method of claim 1, wherein: and step 3, specifically, acquiring the attitude and calculating a course angle by using inertial navigation.

3. The IMU and codewheel fusion based vehicle alignment method of claims 1 or 2, wherein: in step 2, the turning distance delta d of the left wheel and the right wheel of the vehicle is set according to the wheel type mileometer of the two wheels of the vehicle_rL、Δd_rRSetting the wheel center as M_rAt an instantaneous velocity v_rThen the following formula is satisfied

4. The IMU and codewheel fusion based vehicle alignment method of claim 3, further comprising: in step 3, letIs t_mThe attitude quaternion of the moment is abbreviated as Is t_m-1The attitude quaternion of the moment is abbreviated as When n is the reference coordinate system, b is from t_m-1Time t_mThe number of the transformed quaternion of (a),using the angular velocity of rotation of the carrier coordinate system relative to the navigation coordinate systemNote η_mIs from t_m-1Time t_mThe equivalent rotation vector of the time carrier coordinate system b relative to the navigation coordinate system n satisfies the following formula

Technical Field

The invention relates to the technical field of vehicle and system positioning.

Background

The orientation method of the robot has two major difficulties: precision and real-time. The traditional odometer-based orientation method causes inaccurate orientation due to abnormal conditions such as slippage and the like of the robot during traveling; the existing orientation system mainly comprises an orientation system based on a wheel type odometer, an orientation system based on an IMU, an orientation system based on a GPS and an orientation system based on a visual odometer, but has the following defects:

1. disadvantages of wheel-odometer-based orientation systems: the wheel-type odometer-based orientation system obtains the movement information of the robot through an odometer to calculate the current posture of the robot. But the wheel type odometer has poor orientation effect due to low coded disc precision and the phenomenon of skidding and side turning of the wheel.

2. Disadvantages of IMU based orientation systems: the IMU-based orientation system obtains acceleration information of the robot through the IMU, and then integrates to obtain the current posture of the robot. But since its attitude angle is integrated, it will cause its error to increase over time, and its orientation will be less accurate over long movements of the robot.

3. Disadvantages of GPS-based orientation systems: the GPS-based orientation system is used for positioning and orientation by receiving signals transmitted by satellites through a computer. However, GPS is subject to signal limitation, and when the signal is blocked or reflected, the accuracy is severely degraded, especially when the robot cannot realize positioning and orientation in an indoor closed environment.

4. Disadvantages of the visual odometer-based orientation system: the orientation system based on the visual odometer is used for matching the acquired images and then estimating the motion parameters of the robot according to the motion change of the feature points. The method has the disadvantages that the visual odometer usually adopts a sparse feature point matching technology, and when the detected feature points are few, mismatching is easily caused. Matching is also difficult when scene changes are large. Moreover, it takes more time to process the visual image, and it is difficult to meet the requirement of real-time performance.

Disclosure of Invention

The invention aims to provide a vehicle positioning method based on IMU and code disc fusion.

In order to achieve the above object, the basic solution of the present invention provides a vehicle positioning method based on IMU and code wheel fusion, comprising the following steps,

step 1, starting a system;

step 2, code disc data are obtained, and the current position and the course angle theta are calculated;

step 3, obtaining IMU data and calculating a current course angle;

and 4, updating the position by taking the x and y coordinates of the code disc and the course angle of the IMU as the reference.

Further, step 3 is specifically to obtain the attitude and calculate the heading angle by using inertial navigation.

Further, in step 2, the turning distance delta d between the left wheel and the right wheel of the vehicle is set according to the wheel type mileometer of the two wheels of the vehicle_rL、Δd_rRSetting the wheel center as M_rAt an instantaneous velocity v_rThen the following formula is satisfied

Further, in step 3, letIs t_mThe attitude quaternion of the moment is abbreviated as Is t_m-1The attitude quaternion of the moment is abbreviated as When n is the reference coordinate system, b is from t_m-1Time t_mThe number of the transformed quaternion of (a),using the angular velocity of rotation of the carrier coordinate system relative to the navigation coordinate systemNote η_mIs from t_m-1Time t_mThe equivalent rotation vector of the time carrier coordinate system b relative to the navigation coordinate system n satisfies the following formula

The invention has the following advantages:

(1) the positioning system is formed by combining the coded disc and the IMU, the calculation process is simple, complicated calculation is avoided, the calculation efficiency is improved compared with a visual odometer method, and the requirement on real-time performance is met.

(2) The invention uses a method of combining the code disc and the IMU to form an orientation system, and obtains the optimal orientation result in a combination mode. Compared with a method of simply using an odometer and an IMU, the precision is improved.

(3) The invention uses the method of combining the code disc and the IMU to form the directional system, has lower manufacturing cost compared with methods such as a visual odometer, a GPS and the like, and meets the requirement of manufacturing a low-cost robot.

(4) The invention uses the method of combining the code disc and the IMU to form the orientation system, and has simple calculation process and high calculation efficiency in the course of calculating the course angle, thereby meeting the requirement of real-time property. And obtaining an optimal result by combining the obtained course angles, and obtaining a high-precision orientation result.

Drawings

FIG. 1 is a logic block diagram of a vehicle positioning method based on IMU and codewheel fusion in accordance with the present invention;

FIG. 2 is a graph of the comparison of the computational efficiency of the method of the present invention and the visual odometry method;

FIG. 3 is a graph of the average error versus wheel odometry method of the present invention.

Detailed Description

The following is further detailed by the specific embodiments: