阅读说明：本技术 一种基于双pid控制算法的下层控制器控制策略 (Lower-layer controller control strategy based on double PID control algorithm ) 是由 金晓峰 姜赟程 刘兆勇 沈继伟 于 2019-10-18 设计创作，主要内容包括：本发明涉及一种基于双PID控制算法的下层控制器控制策略,其特征在于：具体控制策略如下：S1：根据上层ACC控制器计算得出的期望加速度进行判断,进行加速控制或者减速控制；利用加减速切换机制进行变速保障无顿挫；S2：将实际加速度与期望加速度差值作为系统误差,计算出控制量进行控制,加速与减速控制分别采用两套不同参数的PID控制；S3：保障S1中加减速切换顺畅及无顿挫杆,设定有前车车速或期望车速与自车车速之差的死区,超出死区进行加速或减速状态的重置；本发明中采用两套PID控制模型并联调控,通过考虑到期望加速度与实际加速度之间的时间延长和增益,解决驾驶员因加速过程中产生顿挫感的舒适性问题。(The invention relates to a control strategy of a lower-layer controller based on a double-PID control algorithm, which is characterized in that: the specific control strategy is as follows: s1: judging according to the expected acceleration calculated by the upper ACC controller, and performing acceleration control or deceleration control; the acceleration and deceleration switching mechanism is utilized to carry out speed change guarantee without pause; s2: calculating a control quantity by taking the difference value of the actual acceleration and the expected acceleration as a system error, and controlling the acceleration and the deceleration by respectively adopting two sets of PID (proportion integration differentiation) controls with different parameters; s3: ensuring smooth acceleration and deceleration switching and no pause and pause bar in S1, setting a dead zone with the difference between the speed of the front vehicle or the expected speed and the speed of the self vehicle, exceeding the dead zone and resetting the acceleration or deceleration state; according to the invention, two sets of PID control models are adopted for parallel regulation, and the comfort problem of the driver caused by pause and frustration in the acceleration process is solved by considering the time delay and gain between the expected acceleration and the actual acceleration.)

1. A lower-layer controller control strategy based on a double PID control algorithm is characterized in that: the specific control strategy is as follows:

s1: judging according to the expected acceleration calculated by the upper ACC controller, and performing acceleration control or deceleration control; the acceleration and deceleration switching mechanism is utilized to carry out speed change guarantee without pause;

s2: calculating a control quantity by taking the difference value of the actual acceleration and the expected acceleration as a system error, and controlling the acceleration and the deceleration by respectively adopting two sets of incremental PID (proportion integration differentiation) controls with different parameters;

s3: in S1, the switching between acceleration and deceleration is smooth and no pause or pause is ensured, a dead zone with the difference between the vehicle speed of the front vehicle or the expected vehicle speed and the vehicle speed of the self vehicle is set, and the reset of the acceleration or deceleration state is carried out beyond the dead zone.

2. The lower-layer controller control strategy based on the double PID control algorithm according to claim 1, wherein: in the step S1, when the acceleration value is positive, performing an accelerator opening PID control; when the expected acceleration is negative, the deceleration control judges the numerical value of the expected acceleration, and carries out master cylinder pressure PID control or idle speed control through engine dragging.

3. The lower-layer controller control strategy based on the double PID control algorithm according to claim 1, wherein: the acceleration and deceleration switching mechanism in the step S1 is as follows: when the expected acceleration is a negative value, switching to a deceleration state, and setting a minimum deceleration value; when the expected acceleration is zero, the opening degree of the accelerator is in a step-type steep drop, and the minimum value is 0.88 times of the minimum threshold value; when the desired acceleration is positive, the acceleration state is switched to the acceleration state, and the maximum acceleration value is set.

4. The lower-layer controller control strategy based on the double PID control algorithm according to claim 1, wherein: in S3, if the difference between the preceding vehicle speed or the desired vehicle speed and the vehicle speed is within 1kph, the deceleration control is not triggered, the engine torque is gradually decreased, and the vehicle speed is maintained and is close to the desired vehicle speed.

5. The lower layer controller based on the double PID control algorithm according to claim 1, wherein: in step S1, when the acceleration state is switched to the deceleration state, the engine and the brake are not damaged, and the acceleration control is reset, or vice versa; in order to ensure driving comfort, the engine torque is not directly set to zero, but the acceleration control is reset, the engine torque is linearly reduced in a stepped manner until reaching the minimum engine torque threshold value, and the engine torque enters a braking and decelerating state; the conditions for triggering the reset are the following three: desired acceleration, reset command of dead zone, lower controller switch.

Technical Field

The invention relates to the technical field of control of a self-adaptive cruise underlying controller, in particular to a control strategy of an underlying controller based on a double-PID control algorithm.

Background

Advanced Driver Assistance Systems (ADAS) have been a popular topic since the 90 s of the 20 th century. The ADAS system not only does not provide a warning signal to the driver when the vehicle is off the current lane or in danger of a collision, but also can subjectively intervene in the handling of the vehicle by controlling steering, braking and throttle with the support of the chassis-by-wire system.

An adaptive cruise control system (ACC) is one of the subfunctions among the major functions of an ADAS system. The ACC is intelligent cruise control produced based on a sensor recognition technology, and aims to automatically control through longitudinal motion of a vehicle, so that fatigue of a driver caused for a long time is relieved, driving safety is guaranteed, and auxiliary driving support is provided for the driver in a simple mode. When the distance between the vehicle and the front vehicle is too small, the ACC control unit can appropriately brake the wheels and reduce the output power of the engine through the coordinated action of the anti-lock brake system, the brake-by-wire system and the engine control system, so that the vehicle and the front vehicle can always keep a safe distance.

Disclosure of Invention

The invention aims to provide an ACC lower layer controller control strategy based on a double-PID parallel control algorithm, and the ACC lower layer controller control strategy can solve the problem of comfort of a driver due to pause and frustration in an acceleration process through time extension and gain between expected acceleration and actual acceleration.

In order to solve the technical problems, the technical scheme of the invention is as follows: a lower-layer controller control strategy based on a double PID control algorithm is characterized in that: the specific control strategy is as follows:

s1: judging according to the expected acceleration calculated by the upper ACC controller, and performing acceleration control or deceleration control; the acceleration and deceleration switching mechanism is utilized to carry out speed change guarantee without pause;

s2: calculating a control quantity by taking the difference value of the actual acceleration and the expected acceleration as a system error, and controlling the acceleration and the deceleration by respectively adopting two sets of incremental PID (proportion integration differentiation) controls with different parameters;

s3: in S1, the switching between acceleration and deceleration is smooth and no pause or pause is ensured, a dead zone with the difference between the vehicle speed of the front vehicle or the expected vehicle speed and the vehicle speed of the self vehicle is set, and the reset of the acceleration or deceleration state is carried out beyond the dead zone.

Further, in S1, the acceleration control is performed to perform the accelerator opening PID control when the desired acceleration value is positive; when the expected acceleration is negative, the deceleration control judges the numerical value of the expected acceleration, and carries out master cylinder pressure PID control or idle speed control through engine dragging;

further, in S1, the deceleration switching mechanism is: when the expected acceleration is a negative value, switching to a deceleration state, and setting a minimum deceleration value; when the expected acceleration is zero, the opening degree of the accelerator is in a step-type steep drop, and the minimum value is 0.88 times of the minimum threshold value; when the desired acceleration is positive, the acceleration state is switched to the acceleration state, and the maximum acceleration value is set.

Further, in S3, if the difference between the preceding vehicle speed or the desired vehicle speed and the vehicle speed of the host vehicle is within 1kph, the deceleration control is not triggered, the engine torque is gradually decreased, and the vehicle speed is maintained and is close to the desired vehicle speed.

Further, in step S1, in order to ensure that the acceleration state is switched to the deceleration state, the engine and the brake are not damaged, and the acceleration control is reset, and vice versa; in order to ensure driving comfort, the engine torque is not directly set to zero, but the acceleration control is reset, the engine torque is linearly reduced in a stepped manner until reaching the minimum engine torque threshold value, and the engine torque enters a braking and decelerating state; the conditions for triggering the reset are the following three: desired acceleration, reset command of dead zone, lower controller switch.

The invention has the advantages that:

1) the invention adopts two incremental PID control models for parallel regulation, and PID control has the advantages that: the principle is simple, and the use is convenient; the adaptability is strong; the robustness is strong, the control quality of the method is not sensitive to the change of the controlled object, and the method is very suitable for the environment with severe environment; by considering the time extension and the gain between the expected acceleration and the actual acceleration, the actuator needs the increment of the control quantity, and the incremental PID control has the best effect, thereby solving the comfort problem that the driver feels jerky in the acceleration process.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic engine torque diagram of a dual PID control algorithm based underlying controller control strategy according to the present invention.

FIG. 2 is an interactive logic diagram of the upper and lower ACC controllers based on the control strategy of the lower controller with dual PID control algorithm.

FIG. 3 is a control logic diagram of a lower-level controller control strategy based on a dual PID control algorithm according to the invention.

Detailed Description

The following examples are presented to enable one of ordinary skill in the art to more fully understand the present invention and are not intended to limit the scope of the embodiments described herein.

As shown in fig. 1 to fig. 3, a control strategy of a lower-layer controller based on a dual PID control algorithm is as follows:

s1: judging according to the expected acceleration calculated by the upper ACC controller, and performing acceleration control or deceleration control; the acceleration and deceleration switching mechanism is utilized to carry out speed change guarantee without pause;

s2: calculating a control quantity by taking the difference value of the actual acceleration and the expected acceleration as a system error, and controlling the acceleration and the deceleration by respectively adopting two sets of PID (proportion integration differentiation) controls with different parameters;

s3: in S1, smooth acceleration and deceleration switching and no pause bar are ensured, a dead zone with the difference between the vehicle speed of the front vehicle or the expected vehicle speed and the vehicle speed of the self vehicle is set, and the reset of the acceleration or deceleration state is carried out beyond the dead zone.

In S1, when the acceleration control is positive at the expected acceleration value, carrying out PID control on the accelerator opening; when the expected acceleration is negative in the deceleration control, the master cylinder pressure PID control or the idling control is carried out through the dragging of an engine;

the deceleration switching mechanism in S1 is: when the expected acceleration is a negative value, switching to a deceleration state; when the expected acceleration is zero, the opening degree of the accelerator is in a step-type steep drop, and the minimum value is 0.88 times of the minimum threshold value; when the desired acceleration is positive, the acceleration state is switched to, and the throttle maximum threshold is set.

In S3, if the difference between the preceding vehicle speed or the desired vehicle speed and the vehicle speed is within 1kph, the deceleration control is not activated, the engine torque is gradually decreased, and the vehicle speed is maintained and is close to the desired vehicle speed.

In step S1, when the acceleration state is switched to the deceleration state, the engine and the brake are not damaged, and the acceleration control is reset, or vice versa; in order to ensure driving comfort, the engine torque is not directly set to zero, but the acceleration control is reset, the engine torque is linearly reduced in a stepped manner until reaching the minimum engine torque threshold value, and the engine torque enters a braking and decelerating state; the conditions for triggering the reset are the following three: desired acceleration, reset command of dead zone, lower controller switch.

The principle of the invention is as follows: inputting a simulated expected acceleration value as a positive value, and controlling the acceleration by a lower layer controller through controlling the torque of the engine, wherein the lower layer controller gradually reaches the expected acceleration value but does not exceed a maximum threshold value; the acceleration state can be judged according to the actual acceleration curve.

Inputting a simulated expected acceleration value to be a negative value, carrying out deceleration control by a lower-layer controller through controlling the dragging of an engine or the pressure of a master cylinder, carrying out brake when the torque of the engine reaches a minimum threshold value, adjusting the magnitude of braking force according to the difference between the expected deceleration and the actual deceleration, and reaching the expected deceleration in a short time without exceeding the maximum braking force; the deceleration state may be determined based on the actual deceleration state.

It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.