CN107463098B - Intelligent trolley speed control method and device based on quadratic function - Google Patents

Abstract

The invention discloses an intelligent trolley speed control method based on a quadratic function, which comprises the following steps: constructing a quadratic function between the speed of the intelligent trolley and the steering pulse quantity of the steering engine; acquiring a quadratic term coefficient, a first-order term coefficient and a constant of the quadratic function according to the acquired steering engine steering pulse quantity left limit value, steering engine steering pulse quantity right limit value, maximum driving speed and safe driving speed to obtain an initial expression of the quadratic function; and debugging the quadratic term coefficient, the primary term coefficient and the constant according to the running state of the intelligent trolley, and obtaining a final expression of the quadratic function between the speed of the intelligent trolley and the steering pulse quantity of the steering engine. The invention provides a speed control method for expressing the change relation of real-time speed of an intelligent trolley along with steering pulse quantity of a steering engine by a quadratic function; and only one parameter needs to be adjusted during debugging, so that the parameter setting time is greatly shortened, and the parameter setting efficiency is improved.

Description

A quadratic function-based intelligent car speed control method and device

technical field

The invention relates to the technical field of intelligent control, in particular to a method and device for controlling the speed of an intelligent car based on a quadratic function.

Background technique

In the race, the smart car has to pass various complex road elements such as straights, corners, big S-curves, small S-curves, crosses, right angles and roundabouts. In order to ensure that the smart car runs smoothly on the entire track, it is necessary to set the upper limit safe speed of the track on different track elements. The purpose of the speed control of the smart car is to make the smart car show different characteristics on different track elements, that is, it can give an appropriate speed on different track elements, including: the smart car is as strong as possible when entering the straight. Accurate acceleration characteristics; can accurately and smoothly track the path at the maximum safe speed when driving in a curve, so that the car can pass the track at the fastest speed without overshooting the track or pressing the line of the track . In the process of speed control, the relationship between the speed and the steering pulse amount of the steering gear is very important. In the case of a certain steering gear steering pulse amount, too fast speed may cause the smart car to rush out of the runway, and too slow speed will fail to turn successfully. corner. There is no good method in the prior art that can directly correlate the speed of the smart car with the steering pulse amount of the steering gear.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to propose a method and device for controlling the speed of an intelligent car based on a quadratic function, which directly correlates the real-time speed of the intelligent car with the steering pulse amount of the steering gear.

Based on the above purpose, a quadratic function-based intelligent car speed control method provided by the present invention includes:

Build a quadratic function between the speed of the smart car and the steering pulse amount of the steering gear;

Obtain the left limit value of the steering gear steering pulse amount, the right limit value of the steering gear steering pulse amount, the maximum driving speed and the safe driving speed of the smart car;

The quadratic term coefficient, the linear term coefficient and constant to obtain the initial expression of the quadratic function;

The smart car is driven according to the initial expression, and the quadratic term coefficient, the linear term coefficient and the constant are adjusted according to the driving state, and the final expression of the quadratic function is obtained.

Further, the acquisition of the left limit value of the steering gear steering pulse amount, the right limit value of the steering gear steering pulse amount, the maximum driving speed and the safe driving speed of the intelligent car includes:

Obtain the pulse amount in the sampling period when the steering gear of the smart car is set to the left limit turning angle, as the left limit value LEFT_max of the steering gear steering pulse amount;

Obtain the pulse amount in the sampling period when the steering gear of the smart car is set to the right limit turning angle, as the right limit value RIGHT_max of the steering gear steering pulse amount;

Obtain the maximum speed that the smart car can reach when the smart car travels smoothly on a straight road, as the maximum speed Speed_fast;

Obtain the speed at which the smart car travels inscribed along the centerline of the smallest circular track when the steering gear of the smart car is set to the left limit turning angle or the right limit turning angle, as the safe driving speed Speed_safe;

Wherein, the left limit value LEFT_max of the steering pulse amount of the steering gear and the right limit value RIGHT_max of the steering pulse amount of the steering gear are equal in magnitude and opposite in direction, that is: LEFT_max=-RIGHT_max.

Further, according to the left limit value of the steering gear steering pulse amount, the right limit value of the steering gear steering pulse amount, the maximum driving speed and the safe driving speed, the quadratic term coefficient of the quadratic function is obtained, The coefficients and constants of the first-order term are obtained to obtain the initial expression of the quadratic function, including:

According to the three points of (left limit value of steering pulse amount of steering gear LEFT_max, safe driving speed Speed_safe), (0, maximum driving speed Speed_fast) and (right limit value of steering pulse amount of steering gear RIGHT_max, safe driving speed Speed_safe) three points are obtained by fitting. The quadratic term coefficient, linear term coefficient and constant of the quadratic function are used to obtain the quadratic function, and the quadratic function is:

Wherein, SPEED(t) is the speed of the smart car, and PWM(t) is the steering pulse amount of the steering gear;

Obtain the left limit value LEFT_max of the steering pulse amount of the steering gear, the right limit value RIGHT_max of the steering pulse amount of the steering gear, the maximum travel speed Speed_fast and the initial value of the safe travel speed Speed_safe and substitute them into the quadratic function to obtain The initial expression of the quadratic function.

Further, debugging the quadratic term coefficient, the linear term coefficient and the constant according to the driving state of the smart car, to obtain the quadratic function between the speed of the smart car and the steering pulse amount of the steering gear. The final expression includes: fine-tuning the value of the maximum driving speed Speed_fast according to the driving state of the smart car, obtaining the quadratic term coefficient and the final value of the constant, so as to obtain the speed and rudder of the smart car The final expression of the quadratic function between the steering pulse quantities.

Further, the initial value of the maximum traveling speed Speed_fast is the limit speed of the motor of the smart car multiplied by 80%.

The present invention also provides a quadratic function-based intelligent car speed control device, comprising:

The building block is used to construct the quadratic function between the speed of the smart car and the steering pulse amount of the steering gear;

The acquisition module is used to acquire the left limit value of the steering pulse amount of the steering gear, the right limit value of the steering pulse amount of the steering gear, the maximum driving speed and the safe driving speed of the smart car;

A function generation module, configured to obtain the quadratic term of the quadratic function according to the left limit value of the steering pulse amount of the steering gear, the right limit value of the steering pulse amount of the steering gear, the maximum travel speed and the safe travel speed coefficients, linear coefficients and constants to obtain the initial expression of the quadratic function;

A debugging module, configured to make the smart car drive according to the initial expression, and debug the quadratic term coefficient, the linear term coefficient and the constant according to the driving state, and obtain the final expression of the quadratic function .

Preferably, the acquisition module is further used for:

Obtain the pulse amount in the sampling period when the steering gear of the smart car is set to the left limit turning angle, as the left limit value LEFT_max of the steering gear steering pulse amount;

Obtain the pulse amount in the sampling period when the steering gear of the smart car is set to the right limit turning angle, as the right limit value RIGHT_max of the steering gear steering pulse amount;

Obtain the maximum speed that the smart car can reach when the smart car travels smoothly on a straight road, as the maximum speed Speed_fast;

Obtain the speed at which the smart car travels inscribed along the centerline of the smallest circular track when the steering gear of the smart car is set to the left limit turning angle or the right limit turning angle, as the safe driving speed Speed_safe;

Wherein, the left limit value LEFT_max of the steering pulse amount of the steering gear and the right limit value RIGHT_max of the steering pulse amount of the steering gear are equal in magnitude and opposite in direction, that is: LEFT_max=-RIGHT_max.

Preferably, the function generation module is further used for:

According to the three points of (left limit value of steering pulse amount of steering gear LEFT_max, safe driving speed Speed_safe), (0, maximum driving speed Speed_fast) and (right limit value of steering pulse amount of steering gear RIGHT_max, safe driving speed Speed_safe) three points are obtained by fitting. The quadratic term coefficient, linear term coefficient and constant of the quadratic function are used to obtain the quadratic function, and the quadratic function is:

Wherein, SPEED(t) is the speed of the smart car, and PWM(t) is the steering pulse amount of the steering gear;

Obtain the left limit value LEFT_max of the steering pulse amount of the steering gear, the right limit value RIGHT_max of the steering pulse amount of the steering gear, the maximum travel speed Speed_fast and the initial value of the safe travel speed Speed_safe and substitute them into the quadratic function to obtain The initial expression of the quadratic function.

Preferably, the debugging module is further used for:

According to the driving state of the smart car, fine-tune the value of the maximum speed Speed_fast to obtain the quadratic term coefficient and the final value of the constant, so as to obtain the difference between the speed of the smart car and the steering pulse amount of the steering gear The final expression of the quadratic function of .

Preferably, the initial value of the maximum travel speed Speed_fast obtained by the function generation module is the limit speed of the motor of the smart car multiplied by 80%.

As can be seen from the above, the method and device for the speed control of an intelligent car based on a quadratic function provided by the present invention propose a speed control that expresses the relationship between the real-time speed of the intelligent car and the steering pulse amount of its steering gear through a quadratic function. method; a qualitative and quantitative debugging method for the coefficients of the quadratic function is proposed, only one parameter needs to be adjusted, which greatly shortens the parameter tuning time and improves the efficiency of parameter tuning; the method has good adaptability and can be adjusted according to the steering of the vehicle. The speed can be adjusted dynamically to a certain extent, so that the speed of the car can well match the steering of the intelligent car; the method is simple and easy to implement, and can reduce the loss of the vehicle during the debugging process and reduce the design cost.

Description of drawings

Fig. 1 is the variation curve of the speed with the steering gear steering pulse amount according to the embodiment of the present invention;

2 is a flowchart of a quadratic function-based intelligent car speed control method according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a quadratic function-based intelligent car speed control device according to an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities with the same name but not the same or non-identical parameters. It can be seen that "first" and "second" It is only for the convenience of expression and should not be construed as a limitation to the embodiments of the present invention, and subsequent embodiments will not describe them one by one.

The present invention uses a quadratic function to represent the curve function that the speed changes with the change of the steering pulse amount of the steering gear. Since the most critical factor affecting the speed is the degree of deviation of the center line of the track, but due to some special track elements such as The processing of the cross, the roundabout element and the roundabout element is not processed according to the position of the center line seen, but according to the special turning of an element. But what is certain is that in order to make the smart car pass the track faster and safely, when the steering amount of the steering gear is the largest, the speed should be the smallest; when the steering amount of the steering gear is zero, the speed should be the largest, considering that The smoothness of the speed change, as shown in Figure 1, gives three points to fit the coefficients of the quadratic function.

FIG. 2 is a flowchart of a method for controlling the speed of an intelligent car based on a quadratic function according to an embodiment of the present invention. The embodiment of the present invention discloses a method for controlling the speed of an intelligent car based on a quadratic function, comprising:

S101, constructing a quadratic function between the speed of the smart car and the steering pulse amount of the steering gear.

S102, obtain the left limit value of the steering gear steering pulse amount, the right limit value of the steering gear steering pulse amount, the maximum driving speed and the safe driving speed of the smart car.

S103, according to the left limit value of the steering pulse amount of the steering gear, the right limit value of the steering pulse amount of the steering gear, the maximum driving speed and the safe driving speed, obtain the quadratic term coefficient and the linear term of the quadratic function coefficients and constants to obtain the initial expression of the quadratic function.

S104: Debug the quadratic term coefficient, the linear term coefficient and the constant according to the driving state of the smart car, and obtain the quadratic function between the speed of the smart car and the steering pulse amount of the steering gear final expression.

As another embodiment of the present invention, step S102 obtains the left limit value of the steering gear steering pulse amount, the right limit value of the steering gear steering pulse amount, the maximum driving speed and the safe driving speed of the smart car, including:

S201: Obtain the pulse amount in the sampling period when the steering gear of the smart car is set to the left limit turning angle, as the left limit value LEFT_max of the steering gear steering pulse amount.

S202: Obtain the pulse amount within the sampling period when the steering gear of the smart car is set to the right limit turning angle, as the right limit value RIGHT_max of the steering gear steering pulse amount.

S203: Obtain the maximum speed that the smart car can reach when the smart car runs smoothly on a straight road, as the maximum running speed Speed_fast.

S204, acquiring the speed at which the smart car travels inscribed along the centerline of the smallest circular track when the steering gear of the smart car is set to the left limit turning angle or the right limit turning angle, as the safe travel speed Speed_safe.

Among them, since the capability of the steering gear of the smart car is symmetrical, the left limit value LEFT_max of the steering pulse amount of the steering gear is equal in magnitude and opposite in direction to the right limit value RIGHT_max of the steering pulse amount of the steering gear, that is: LEFT_max=-RIGHT_max. The sequence of steps S201-204 can be modified arbitrarily.

As another embodiment of the present invention, in step S103, obtaining the said steering gear according to the left limit value of the steering pulse amount of the steering gear, the right limit value of the steering pulse amount of the steering gear, the maximum travel speed and the safe travel speed The quadratic term coefficient, linear term coefficient and constant of the quadratic function are obtained to obtain the initial expression of the quadratic function, including:

S301, according to three points (left limit value of steering pulse amount of steering gear LEFT_max, safe traveling speed Speed_safe), (0, maximum traveling speed Speed_fast) and (right limit value of steering pulse amount of steering gear RIGHT_max, safe traveling speed Speed_safe) Combine the quadratic term coefficients, linear term coefficients and constants of the quadratic function to obtain the quadratic function, where the quadratic function is:

Wherein, SPEED(t) is the speed of the smart car, and PWM(t) is the steering pulse amount of the steering gear. (left limit value of steering gear pulse amount LEFT_max, safe driving speed Speed_safe), (right limit value of steering gear steering pulse amount RIGHT_max, safe driving speed Speed_safe) means when the steering gear of the smart car is set to the left limit turning angle LEFT_max or the right limit turning angle At RIGHT_max, the smart car is at the safe speed Speed_safe. (0, the maximum speed Speed_fast) indicates that the smart car is at the maximum speed Speed_fast when the smart car does not deflect while driving on a straight road.

S302: Obtain the initial values of the steering gear steering pulse amount left limit value LEFT_max, the steering gear steering pulse amount right limit value RIGHT_max, the maximum travel speed Speed_fast, and the safe travel speed Speed_safe, and substitute them into the quadratic function , obtain the initial expression of the quadratic function.

Among them, the initial values of the left limit value LEFT_max of the steering pulse amount of the steering gear and the right limit value of the steering pulse amount of the steering gear RIGHT_max are related to the performance of the steering gear, and are the physical parameters of the steering gear, which are easy to measure; the maximum speed Speed_fast is According to the capability of the motor, the tires of the smart car, and the material properties of the track, the safe speed that can be reached with the maximum steering capability of the steering gear; in a specific embodiment, the initial value of the maximum speed Speed_fast is the speed of the smart car. The limit speed of the motor is multiplied by eighty percent. Therefore, once the wheel, steering gear and field materials are determined, it is also easy to determine the value. It is therefore only necessary to determine the safe driving speed Speed_safe.

The specific method for determining the safe driving speed Speed_safe is to estimate the maximum safe speed of the smart car on a small circular track. In a specific embodiment, the radius of the small annular racetrack is 50cm. When measuring, set the steering gear of the smart car to a fixed left limit turning angle or right limit turning angle; when the car runs at a slow speed, the car can turn a circle with a small radius; as the speed increases, the intelligent The radius of the ring run by the car is getting larger and larger; when the ring run by the smart car is just tangent to the center line of the track, when the car can run smoothly without sideslip, write down the speed value at this time as the safe driving speed Speed_safe . This is because if the smart car runs inside the ring, the safe driving speed will not be fully utilized, the car will not run out of the highest speed, and it will not complete the race at the fastest speed; When the safe speed is exceeded and the unstable speed is reached, the car is very prone to sideslip or even pressing the line or rushing out of the track.

以及所述常量Speed_fast的最终值，从而得到所述智能小车的速度与舵机转向脉冲量之间的二次函数的最终表达式。首先，由于一次项系数为0，不需要进行调试；二次项系数与常量只包含了Speed_fast、Speed_safe和舵机左、右极限能力LEFT_max和RIGHT_max，其中LEFT_max和RIGHT_max，与具体舵机性能有关，是舵机的物理参数，Speed_safe是根据电机的能力和小车轮胎以及地面材料特性测试出来的以舵机最大转向能力所能走出的安全速度，所以一旦车轮、舵机和场地材料确定，也是比较确定的量，所以只需要根据情况来修改Speed_fast的值。结合MATLAB进行分析，如果直道飞车，则减小Speed_fast的值，减小到智能小车能够在所有赛道跑得好的状态就是直道时在赛道中间快速前行，入弯能够迅速且平稳减速，出弯能够迅速且平稳的加速通过各种曲线型赛道，当通过十字时仍然能快速通过，入环岛时能平稳迅速减速，出环岛能够迅速加速时即得到二次函数的最终表达式。由于本发明实施例在系数调试时只需要针对一个系数即Speed_fast进行调试，故可以大大缩短参数调整的时间，提高整体整定参数的效率。Further, after obtaining the initial expression of the quadratic function, it is necessary to debug each coefficient, so as to obtain a better function representing the relationship between the speed and the steering pulse amount of the steering gear. In this embodiment, in step 104, the quadratic term coefficient, the linear term coefficient and the constant are adjusted according to the driving state of the smart car to obtain the speed of the smart car and the steering pulse amount of the steering gear The final expression of the quadratic function between , including: according to the driving state of the smart car, fine-tuning the value of the maximum driving speed Speed_fast to obtain the quadratic term coefficient

and the final value of the constant Speed_fast, so as to obtain the final expression of the quadratic function between the speed of the smart car and the steering pulse amount of the steering gear. First of all, since the coefficient of the primary term is 0, no debugging is required; the coefficients and constants of the quadratic term only include Speed_fast, Speed_safe and the left and right limit capabilities of the steering gear, LEFT_max and RIGHT_max, of which LEFT_max and RIGHT_max are related to the specific performance of the steering gear. It is the physical parameter of the steering gear. Speed_safe is the safe speed that can be reached with the maximum steering capability of the steering gear based on the capability of the motor, the characteristics of the car tires and the ground material, so once the wheel, steering gear and site materials are determined, it is also relatively certain. , so you only need to modify the value of Speed_fast according to the situation. Combined with MATLAB for analysis, if the car is flying on a straight, reduce the value of Speed_fast to the point where the smart car can run well on all tracks, that is, when the straight track is in the middle of the track, it can quickly and smoothly decelerate into the corner. It can quickly and smoothly accelerate through various curvilinear racetracks when exiting a corner. When passing a cross, it can still pass quickly. When entering a roundabout, it can decelerate smoothly and quickly. When it can quickly accelerate out of a roundabout, the final expression of the quadratic function can be obtained. Since only one coefficient, Speed_fast, needs to be debugged in the embodiment of the present invention, the parameter adjustment time can be greatly shortened, and the overall parameter adjustment efficiency can be improved.

The embodiment of the present invention also provides a quadratic function-based intelligent car speed control device, including:

The building module 10 is used to build a quadratic function between the speed of the smart car and the steering pulse amount of the steering gear.

The obtaining module 11 is used to obtain the left limit value of the steering pulse amount of the steering gear, the right limit value of the steering pulse amount of the steering gear, the maximum driving speed and the safe driving speed of the smart car.

The function generation module 12 is used to obtain the quadratic function of the quadratic function according to the left limit value of the steering pulse amount of the steering gear, the right limit value of the steering pulse amount of the steering gear, the maximum travel speed and the safe travel speed term coefficients, linear term coefficients, and constants to obtain the initial expression of the quadratic function.

The debugging module 13 is used to debug the quadratic term coefficient, the first-order term coefficient and the constant according to the driving state of the smart car, and obtain the relationship between the speed of the smart car and the steering pulse amount of the steering gear. The final expression of the quadratic function.

Preferably, the acquisition module 11 is further used for:

The pulse amount within the sampling period when the steering gear of the smart car is set to the left limit turning angle is obtained as the left limit value LEFT_max of the steering gear steering pulse amount.

The pulse amount within the sampling period when the steering gear of the smart car is set to the right limit turning angle is obtained as the right limit value RIGHT_max of the steering gear steering pulse amount.

The maximum speed that the smart car can reach when the smart car runs smoothly on a straight road is obtained as the maximum running speed Speed_fast.

When the steering gear of the smart car is set to the left limit turning angle or the right limit turning angle, the speed at which the smart car travels inscribed along the center line of the smallest circular track is obtained as the safe travel speed Speed_safe.

Wherein, the left limit value LEFT_max of the steering pulse amount of the steering gear and the right limit value RIGHT_max of the steering pulse amount of the steering gear are equal in magnitude and opposite in direction, that is: LEFT_max=-RIGHT_max.

Preferably, the function generation module 12 is further used for:

Perform fitting according to three points (LEFT_max, Speed_safe), (0, Speed_fast) and (RIGHT_max, Speed_safe) to obtain the quadratic term coefficient, linear term coefficient and constant of the quadratic function, and obtain the quadratic function, so The quadratic function is:

Wherein, SPEED(t) is the speed of the smart car, and PWM(t) is the steering pulse amount of the steering gear;

Obtain the left limit value LEFT_max of the steering pulse amount of the steering gear, the right limit value RIGHT_max of the steering pulse amount of the steering gear, the maximum travel speed Speed_fast and the initial value of the safe travel speed Speed_safe and substitute them into the quadratic function to obtain The initial expression of the quadratic function.

Preferably, the debugging module 13 is further used for:

According to the driving state of the smart car, fine-tune the value of the maximum speed Speed_fast to obtain the quadratic term coefficient and the final value of the constant, so as to obtain the difference between the speed of the smart car and the steering pulse amount of the steering gear The final expression of the quadratic function of .

Preferably, the initial value of the maximum travel speed Speed_fast obtained by the function generation module 13 is the limit speed of the motor of the smart car multiplied by 80%.

The method and device for speed control of an intelligent car based on a quadratic function of the present invention proposes a speed control method in which a quadratic function is used to express the relationship between the real-time speed of an intelligent car and the steering pulse amount of its steering gear; The qualitative and quantitative debugging method of the term coefficient only needs to adjust one parameter, which greatly shortens the parameter setting time and improves the efficiency of parameter setting. This method has good adaptability and can dynamically adjust the speed according to the steering degree of the vehicle, so that the car The speed of the smart car is well matched with the steering of the smart car; the acceleration and deceleration effect of controlling the smart car is better, and the smart car can be controlled to accelerate smoothly and quickly when entering a corner, and accelerate smoothly and quickly when exiting a corner according to the needs of the smart car; this method is simple and easy to implement, and can Reduce the loss of the vehicle during the debugging process and reduce the design cost.

Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is only exemplary, and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples; under the spirit of the present invention, the above embodiments or There may also be combinations between technical features in different embodiments, steps may be carried out in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Additionally, well known power/ground connections to integrated circuit (IC) chips and other components may or may not be shown in the figures provided in order to simplify illustration and discussion, and in order not to obscure the present invention. . Furthermore, devices may be shown in block diagram form in order to avoid obscuring the present invention, and this also takes into account the fact that the details regarding the implementation of these block diagram devices are highly dependent on the platform on which the invention will be implemented (i.e. , these details should be fully within the understanding of those skilled in the art). Where specific details (eg, circuits) are set forth to describe exemplary embodiments of the invention, it will be apparent to those skilled in the art that these specific details may be made without or with changes The present invention is carried out below. Accordingly, these descriptions are to be regarded as illustrative rather than restrictive.

Although the present invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations to these embodiments will be apparent to those of ordinary skill in the art from the foregoing description. For example, other memory architectures (eg, dynamic RAM (DRAM)) may use the discussed embodiments.

Embodiments of the present invention are intended to cover all such alternatives, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A method for controlling the speed of an intelligent trolley based on a quadratic function is characterized by comprising the following steps:

constructing a quadratic function between the speed of the intelligent trolley and the steering pulse quantity of the steering engine;

acquiring a left limit value of steering pulse quantity of a steering engine, a right limit value of steering pulse quantity of the steering engine, a maximum driving speed and a safe driving speed of the intelligent trolley;

acquiring a quadratic term coefficient, a first-order term coefficient and a constant of the quadratic function according to the steering engine steering pulse quantity left limit value, the steering engine steering pulse quantity right limit value, the maximum driving speed and the safe driving speed to obtain an initial expression of the quadratic function;

enabling the intelligent trolley to run according to the initial expression, debugging the secondary term coefficient, the primary term coefficient and the constant according to a running state, and obtaining a final expression of the secondary function;

the method for acquiring the steering pulse quantity left limit value, the steering pulse quantity RIGHT limit value, the maximum driving Speed and the safe driving Speed of the intelligent trolley comprises the steps of acquiring the pulse quantity in a sampling period when the steering engine of the intelligent trolley is set to be a left limit corner, taking the pulse quantity as L EFT _ max of the steering pulse quantity left limit value, acquiring the pulse quantity in the sampling period when the steering engine of the intelligent trolley is set to be a RIGHT limit corner, taking the pulse quantity as RIGHT _ max of the steering pulse quantity RIGHT limit value, acquiring the maximum Speed which can be reached by the intelligent trolley when the intelligent trolley stably drives on a straight road, taking the maximum driving Speed Speed _ fast, acquiring the Speed which the intelligent trolley drives along the central line of a minimum circular track when the steering engine of the intelligent trolley is set to be the left limit corner or the RIGHT limit corner, and taking the Speed as the safe driving Speed Speed _ safe, wherein the steering pulse quantity left limit value L EFT _ max of the steering engine is equal to the steering pulse quantity RIGHT limit value RIGHT _ max, and the directions are opposite, namely L EFT _ max is-RIGHT _ max;

the obtaining of the quadratic term coefficient, the first order coefficient and the constant of the quadratic function according to the steering engine steering pulse quantity left limit value, the steering engine steering pulse quantity right limit value, the maximum driving speed and the safe driving speed includes:

fitting according to three points (steering engine steering pulse left limit value L EFT _ max, safe driving Speed _ safe), (0, maximum driving Speed _ fast) and (steering engine steering pulse RIGHT limit value RIGHT _ max, safe driving Speed _ safe) to obtain a quadratic term coefficient, a first order term coefficient and a constant of the quadratic function, so as to obtain the quadratic function, wherein the quadratic function is as follows:

speed (t) is the speed of the intelligent trolley, and PWM (t) is the steering pulse quantity of the steering engine;

and acquiring initial values of the steering engine steering pulse quantity left limit value L EFT _ max, the steering engine steering pulse quantity RIGHT limit value RIGHT _ max, the maximum driving Speed and the safe driving Speed safe, and substituting the initial values into the quadratic function to obtain an initial expression of the quadratic function.

2. The intelligent vehicle speed control method based on the quadratic function according to claim 1, wherein the step of debugging the quadratic coefficient, the first order coefficient and the constant according to the driving state of the intelligent vehicle to obtain a final expression of the quadratic function between the speed of the intelligent vehicle and the steering engine steering pulse quantity comprises the steps of: and finely adjusting the numerical value of the maximum driving Speed _ fast according to the driving state of the intelligent trolley to obtain the quadratic coefficient and the final value of the constant, so as to obtain a final expression of a quadratic function between the Speed of the intelligent trolley and the steering pulse quantity of the steering engine.

3. The quadratic function-based smart car Speed control method according to claim 1, characterized in that the initial value of the maximum travel Speed _ fast is a limit Speed of a motor of the smart car multiplied by eighty percent.

4. The utility model provides an intelligent vehicle speed control device based on quadratic function which characterized in that includes:

the building module is used for building a quadratic function between the speed of the intelligent trolley and the steering pulse quantity of the steering engine;

the acquisition module is used for acquiring a steering engine steering pulse quantity left limit value, a steering engine steering pulse quantity right limit value, a maximum driving speed and a safe driving speed of the intelligent trolley;

the function generating module is used for acquiring a quadratic term coefficient, a first-order term coefficient and a constant of the quadratic function according to the steering engine steering pulse quantity left limit value, the steering engine steering pulse quantity right limit value, the maximum driving speed and the safe driving speed to obtain an initial expression of the quadratic function;

the debugging module is used for enabling the intelligent trolley to run according to the initial expression, debugging the secondary term coefficient, the primary term coefficient and the constant according to a running state and obtaining a final expression of the secondary function;

the acquisition module is further used for acquiring pulse quantity in a sampling period when a steering engine of the intelligent trolley is set to be in a left limit corner as a steering pulse quantity left limit value L EFT _ max of the steering engine, acquiring pulse quantity in the sampling period when the steering engine of the intelligent trolley is set to be in a RIGHT limit corner as a steering pulse quantity RIGHT limit value RIGHT _ max of the steering engine, acquiring the maximum Speed which can be reached by the intelligent trolley when the intelligent trolley runs stably on a straight road as the maximum running Speed Speed _ fast, and acquiring the Speed of the intelligent trolley running internally along the central line of a minimum circular track when the steering engine of the intelligent trolley is set to be in the left limit corner or the RIGHT limit corner as the safe running Speed Speed _ safe, wherein the steering engine steering quantity left limit value L EFT _ max is equal to the steering pulse quantity RIGHT limit value RIGHT _ max of the steering engine in size and opposite in direction, namely L EFT _ max is-RIGHT _ max;

the function generation module is further used for fitting according to three points (steering engine steering pulse quantity left limit value L EFT _ max, safe driving Speed _ safe), (0, maximum driving Speed _ fast) and (steering engine steering pulse quantity RIGHT limit value RIGHT _ max, safe driving Speed _ safe) to obtain a quadratic term coefficient, a first-order term coefficient and a constant of the quadratic function, and obtaining the quadratic function, wherein the quadratic function is as follows:

speed (t) is the speed of the intelligent trolley, and PWM (t) is the steering pulse quantity of the steering engine;

and acquiring initial values of the steering engine steering pulse quantity left limit value L EFT _ max, the steering engine steering pulse quantity RIGHT limit value RIGHT _ max, the maximum driving Speed and the safe driving Speed safe, and substituting the initial values into the quadratic function to obtain an initial expression of the quadratic function.

5. The intelligent cart speed control device based on quadratic function according to claim 4, characterized in that the debugging module is further used for:

and finely adjusting the numerical value of the maximum driving Speed _ fast according to the driving state of the intelligent trolley to obtain the quadratic coefficient and the final value of the constant, so as to obtain a final expression of a quadratic function between the Speed of the intelligent trolley and the steering pulse quantity of the steering engine.

6. The intelligent vehicle Speed control device based on quadratic function according to claim 4, characterized in that the initial value of the maximum driving Speed _ fast obtained by the function generation module is the limit Speed of the motor of the intelligent vehicle multiplied by eighty percent.

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