CN109947104B

CN109947104B - Automatic tracking method for unilateral roundabout

Info

Publication number: CN109947104B
Application number: CN201910236983.1A
Authority: CN
Inventors: 邱成杰; 蔡昌春; 刘皖熠; 刘乘杰
Original assignee: Hohai University HHU
Current assignee: Nanjing Tianzheng Industrial Intelligent Technology Research Institute Co ltd
Priority date: 2019-03-27
Filing date: 2019-03-27
Publication date: 2021-12-21
Anticipated expiration: 2039-03-27
Also published as: CN109947104A

Abstract

The invention discloses a single-side roundabout automatic tracking method, which belongs to the field of automatic driving. The method includes the following steps: sequentially switching the smart car from a normal state to an unlocked state, a loop strategy state, an in-loop tracking state, and a normal state to complete a round-the-island automatic tracking process. Compared with the traditional threshold-triggered and directional turn-around tracking algorithm, the present invention can reflect road information more accurately and in real time, so that the tracking of the smart car is more stable, smooth and precise.

Description

Automatic tracking method for unilateral roundabout

Technical Field

The invention relates to the field of intelligent automobile automatic driving, in particular to a unilateral roundabout automatic tracking method.

Background

In recent years, an intelligent automobile tracking algorithm based on electromagnetic induction is widely applied. However, the identification and processing of the specific paths still remains in the preliminary stage of comparison. With the popularization of intelligent automobiles, more and more roads are opened to the intelligent automobiles, and the development of an automatic tracking algorithm of a special path becomes a very difficult problem. In addition, with the sophistication of traffic systems and the advancement of related electronic technologies, there will be an ever-increasing market for the identification and tracking of specific routes.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a single-side rotary island automatic tracking method which is used for solving the problem that the existing algorithm in the prior art cannot accurately identify and track a single-side rotary island.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a single-side rotary island automatic tracking method comprises the following steps,

and switching the intelligent automobile from the conventional state into an unlocking state, a ring strategy state, a ring tracking state and a conventional state in sequence to complete the automatic tracking process of the ring island.

Further, the process of switching into the unlocked state includes:

obtaining a weighted accumulated value of the inductance pair, and judging whether the size of the weighted accumulated value meets an annular island unlocking threshold value;

converting the running state from the conventional state into an unlocking state;

further, the process of switching into the ring policy state includes:

obtaining a weighted accumulation value of the inductance pair, and judging whether the change trend of the weighted accumulation value meets the requirement that a saddle point appears after the change trend rises to a peak value;

confirming the existence of a roundabout and a roundabout point;

and switching the running state from the unlocking state to the ring strategy state.

Further, the process of switching into the in-loop tracking state comprises:

switching to a tracking inductance pair, and detecting an electromagnetic signal of the overlapped electromagnetic signal in the backward facing ring;

the tracking inductance pair comprises a horizontal inductance pair I and a horizontal inductance pair II;

processing the sampling data of the horizontal inductor pair two to obtain a difference ratio and using the difference ratio as the deviation of an automobile direction ring, so that the automobile moves away from a tangent part of a circular island and a straight road along the magnetic field of the ring-shaped lead;

detecting to obtain the difference ratio sum of the horizontal inductance to one;

judging whether the difference ratio sum of the horizontal inductance to one is stable, reaches a normal value and meets the curvature deviation requirement;

and switching the running state from the loop strategy state to the in-loop tracking state.

Further, the process of switching to the normal state includes:

obtaining a weighted accumulated value of the inductance pair, and observing the trend of the weighted accumulated value;

judging whether the weighted accumulated sum value has magnetic field abnormality or not, and eliminating the abnormal magnetic field value after a peak value, a saddle point and a second peak value appear in sequence;

obtaining a position away from the rotary island;

and switching the running state from the in-loop tracking state to the normal state.

Further, the threshold value for leaving the rotary island is a stable value on a conventional single-line straight track.

Further, the inductance pair comprises a horizontal inductance pair and a vertical inductance pair;

the inductance pair comprises a horizontal inductance pair one and a horizontal inductance pair two.

The method can be realized by arranging the following modules on the intelligent automobile:

a control zone bit adjusting module: dividing a circular island tracking strategy into four parts, and unlocking corresponding state zone bits through continuous trigger conditions;

a timeout correction module: the timer interruption is started in the normal running process of the program, and through the accumulated calculation of the running period, when the accumulated value exceeds a specified threshold value, the current state flag bit is eliminated and the current state flag bit returns to the state 0, so that the program card is prevented from influencing the triggering of the next roundabout in a certain state, and the running stability of the algorithm is effectively improved;

an in-loop control policy module: the control scheme for in-loop control uses cascaded PID control essentially the same as for normal operating conditions, with the difference that the control in-loop requires a faster response to expectations, i.e. the proportional parameter is larger, and the settling has less impact on system stability, i.e. pure P control can be used, than PID control for normal operating conditions.

Compared with the prior art, the invention has the following beneficial effects:

when the electromagnetic tracking-based tracker faces the path of the single-side rotary island, the method can realize accurate and effective actions such as fast ring entering, stable operation, accurate ring exiting and the like by carrying out state recognition on the processing of the sampling value of the sensor and controlling and switching in different stages.

Drawings

FIG. 1 is a logic diagram of the algorithm in actual operation;

FIG. 2 is an electromagnetic look-ahead diagram for use with the present algorithm;

FIG. 3 is a schematic diagram of the electromagnetic guideline used in the present algorithm;

FIG. 4 is a schematic diagram of the control strategy state switching points within a ring of the present algorithm;

fig. 5 is a diagram of the effect of policy switching during actual operation of the algorithm.

Reference numerals: 1. a first position; 2. a second position; 3. position three; 4. a fourth position; 5. position five; 6. a first operational amplifier circuit; 7. a second operational amplifier circuit; 8. a third operational amplifier circuit; 9. a vertical inductor; 10. a first horizontal inductor; 11. a vertical inductance; 12. and a second horizontal inductor.

Detailed Description

The invention is further described below. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in fig. 1, a single-sided circular island automatic tracking method includes the following steps,

The process of switching into the unlocked state comprises the following steps:

and converting the running state from the normal state to the unlocking state.

Specifically, the method comprises the following steps: the pair of horizontal inductors are horizontally distributed on the left end and the right end of the foresight with the same vehicle width in parallel to the ground and used for detecting abnormal values of a magnetic field in the horizontal direction around the rotary island; the pair of vertical inductors are distributed on the left end and the right end of the equal vehicle width in a manner of being vertical to the ground upwards and used for detecting abnormal values of the magnetic field in the vertical direction around the rotary island.

The process of switching into the ring policy state comprises:

confirming the existence of a roundabout and a roundabout point;

Observing the vertical inductance in the process from the unlocking state to the loop strategy state, and comparing the measured values of the left vertical inductance and the right vertical inductance to obtain whether the specific position of the loop island is positioned on the left side or the right side of the loop point;

the process of switching into an in-loop tracking state comprises:

In the process from the ring strategy state to the in-ring tracking state, the inductors used for tracking are correspondingly and horizontally distributed on two sides of the forward-looking central line and used for accurately finding the fork positions of the overlapped electromagnetic lines, and the position difference ratio of the ring island and the deviation are led to point to the ring through the state. The sum of the inductance difference at two ends of the tracking state in the trigger ring is generally a deviation value on an equal-curvature curve in a conventional single-wire state, and the value needs not to change greatly in a certain period.

The in-loop tracking state must be triggered on the premise that the loop policy state is triggered.

The process of switching to the normal state comprises the following steps:

obtaining a position away from the rotary island;

The same operating strategy as in the conventional state is used in the in-loop tracking state, and the weighted accumulated sum of the inductance pairs is detected and the trend thereof is observed. And (3) when the magnetic field abnormality is detected, and the peak value, the saddle point and the second peak value appear in sequence, the abnormal magnetic field value disappears, the position of the intelligent automobile leaving the rotary island is obtained, and the normal operation is switched.

And the deviation of the direction loop is adjusted by using low-pass filtering in the section state, so that the condition of secondary loop feeding is ensured not to occur. The threshold value of the out-loop is a stable value of the intelligent vehicle on a conventional single-line straight track, and can be adjusted up and down according to specific needs, but the maximum value is smaller than fifty percent of the second peak value.

The inductance pair mentioned hereinabove includes a horizontal inductance pair and a vertical inductance pair;

The weighted accumulation values are obtained by a horizontal inductance pair and a vertical inductance pair.

The judgment conditions presented above all enter the next step when the conditions are satisfied.

As shown in fig. 2, the electromagnetic look ahead of the intelligent automobile is provided, wherein an operational amplifier circuit i 6, an operational amplifier circuit ii 7 and an operational amplifier circuit iii 8 are arranged on the electromagnetic look ahead; the operational amplification circuit is used for carrying out proportional amplification on the signals acquired by the inductor; the vertical inductor 9 looks ahead vertically and is used for detecting a curve; the horizontal inductor I10 is used for conventional tracking in parallel; the vertical inductor 11 is vertically upward and used for detecting the position of the rotary island; and the horizontal inductor two 12 is close to a prospective center line and used for detecting the loop island bifurcation electromagnetic field.

The four inductors are provided with a same inductor symmetrically at prospective symmetrical positions, so that four pairs of inductors are formed, namely a vertical inductor pair, a horizontal inductor pair I, a vertical inductor pair and a horizontal inductor pair II.

As shown in fig. 3 and 4, the diagram is a circuit diagram of the intelligent automobile circular island tracking, and an acute angle of the diagram is a forward direction of the intelligent automobile tracker, and the intelligent automobile firstly moves to a position 1 in a normal state; then, the tracking device continues to advance to a second position 2 where the tracking device enters an unlocking state from a conventional state; then reaching the position three 3, which is the optimal ring entering position, namely a switching point of the state unlocking state entering the ring strategy state; then, the position is determined for entering the ring at the position of the fourth 4, and the tracker confirms that the tracker enters the ring island by itself through the point, namely, the switching point from the ring strategy state to the ring inner tracking state; finally position five 5 is reached, i.e. the loop point is confirmed, which confirms that the tracker has left the loop island, i.e. the switching point of the intra-state tracking state to the normal state.

As shown in FIG. 5, a waveform diagram of the status of the successful operation of the tracker at the operation speed of 2.4M/S in the rotary island is shown, which shows the dynamic conditions of the status flag, the weighted monitoring value, the normal control deviation and the in-loop control deviation in the whole rotary island motion process.

An application of an intelligent automobile tracking method based on electromagnetic tracking. The most common method is to perform induction sampling on an alternating current electric wire with determined frequency and amplitude by using an I-shaped inductor to an electromagnetic induction theorem, and then convert the induction sampling into a deviation amount of the moving device central line relative to a path central line through an operational amplification circuit and a related algorithm. At present, the method is mainly applied to the fields of intelligent automobiles, unmanned aerial vehicles and the like. Electromagnetic tracking techniques have been described in general terms in the literature.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. A single-side rotary island automatic tracking method is characterized in that: the method comprises the following steps of,

switching the intelligent automobile from a conventional state into an unlocking state, a ring strategy state, a ring tracking state and a conventional state in sequence to complete a ring island automatic tracking process;

the process of switching into the unlocked state comprises the following steps:

the process of switching into the ring policy state comprises:

confirming the existence of a roundabout and a roundabout point;

switching the running state from the unlocking state to a ring strategy state;

the process of switching into an in-loop tracking state comprises:

switching the running state from the loop strategy state to an in-loop tracking state;

the process of switching to the normal state comprises the following steps:

obtaining a position away from the rotary island;

2. The method of claim 1, wherein the method comprises: the threshold value leaving the rotary island is a stable value on a conventional single linear track.

3. The method of claim 1, wherein the method comprises:

the inductance pair comprises a horizontal inductance pair and a vertical inductance pair;