Quintic curve path planning method and lane center line maintenance method

A path planning and lane line technology, applied to motor vehicles, two-dimensional position/channel control, vehicle position/route/height control, etc., can solve the problem of large steering wheel swing, poor cubic curve following performance, and vehicles that cannot follow the preset Tracking and other problems, to achieve the effect of continuous and smooth curvature changes, high real-time performance, and reduced dimensionality and difficulty

Active Publication Date: 2020-03-27
纽劢科技(上海)有限公司
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Problems solved by technology

[0004] The difficulty of the path planning algorithm is to design a trajectory model so that the model can meet the conditions for the vehicle to change from the current attitude to the target attitude. Most automatic driving systems use the cubic curve model as the trajectory model, which is better than the automatic driving of Mingkoya University in Japan. The path planning curve hermit curve used in the open source project autoware simulator is this cubic curve model. The trajectory model of the cubic curve requires the trajectory curve to satisfy the position of the starting point and the end point tra

Method used

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  • Quintic curve path planning method and lane center line maintenance method
  • Quintic curve path planning method and lane center line maintenance method
  • Quintic curve path planning method and lane center line maintenance method

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Embodiment 1

[0033] First, the path planning step is performed, see figure 1 The state models of the starting point S and the ending point T of the vehicle described in this embodiment, as well as the trajectory model path(x) and the lane line model are all represented by the vehicle body coordinate system, and the coordinate origin of the vehicle body coordinate system is at the two rear wheels of the vehicle. The midpoint of the line, the rear wheel connection is the y-axis of the vehicle body coordinate system, looking from the midpoint of the rear wheel connection midpoint to the front wheel connection midpoint, the left is the positive direction of the y-axis of the vehicle body coordinate system, and the y-axis The vertical forward direction is the positive direction of the x-axis of the vehicle body coordinate system, that is, the direction from the midpoint of the rear wheel connection to the midpoint of the front wheel connection; the instantaneous motion characteristics of the veh...

Embodiment 2

[0064] Trajectory planning during automatic driving requires clear lane lines to be realized, and the vehicle body will become unstable when the lane lines are suddenly invisible. This embodiment combines the quintic curve planning method described above to realize the maintenance of the lane centerline. Keep the car body stable when the lane line is suddenly invisible.

[0065] Step 1: Track the feature points of the lane line, calculate the quality of the received lane line as poor quality, and discard the calculated lane line data as poor quality, specifically including the following steps 1.1-1.8.

[0066] Step 1.1. The algorithm runs in a fixed cycle, and the running cycle is H Hz, which means it runs every 1 / H second.

[0067] Step 1.2, in the t-th planning period, the center line of the lane is represented by a cubic curve (y=f t (x)=c 3 x 3 +c 2 x 2 +c 1 x+c 0 ).

[0068] Step 1.3. In the t-th planning cycle, calculate the set of feature points in the local coo...

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Abstract

The invention relates to the technical field of automatic driving, in particular to a quintic curve path planning method and a lane center line maintenance method. The invention comprises the following steps of adopting a quadruple (x, y, r, k) in a vehicle body coordinate system of a vehicle to describe a state model of the vehicle, and position limitation, curvature limitation and attitude limitation conditions of a track starting point S are set; setting a position limit, a curvature limit and an attitude limit condition of a track end point T; and solving the n-order curve model meeting all the limiting conditions in the step a and the step b, wherein n is a positive integer greater than or equal to 5. The path obtained through the method not only meets the pose condition of the starting point, but also gives a limiting condition to the curvature of the track of the starting point, and the smoothness of steering control of the vehicle is guaranteed. The following performance is very good, step jump of steering wheel control is avoided, and a real vehicle test verification result also shows that when automatic driving control is carried out according to the method, the comfortof riding experience of people is not obviously different from the control effect of a human driver.

Description

technical field [0001] The invention relates to the technical field of automatic driving, in particular to a quintic curve path planning method and a lane centerline maintenance method. Background technique [0002] An important task in automatic driving is to enable the computer to replace the human to automatically control the steering wheel of the vehicle, so as to ensure that the vehicle can automatically drive on the road with a reasonable and safe position and posture. The most typical function in the L3 automatic driving application scenario is lane keeping. This function requires the vehicle to be in the middle of the lane and drive along the direction of the lane line. In most lane keeping application scenarios, the vehicle is required to It is necessary to configure an image sensor or other positioning sensors to detect the current position and attitude of the vehicle. For example, some image sensors can detect the shape model of the lane line of the vehicle's lane...

Claims

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Application Information

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IPC IPC(8): G05D1/02
CPCG05D1/0253G05D1/0214G05D1/0221G05D1/0276G05D2201/02Y02T10/40
Inventor 王希平吕强
Owner 纽劢科技(上海)有限公司
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