CN114637296B - Tracking control system and control method for PRT vehicle - Google Patents
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Abstract
The invention belongs to the field of unmanned track traffic, and particularly relates to a tracking control system and a control method of a PRT vehicle. The control system includes: a positioning information acquisition unit, a vehicle information calculation unit, an offset information calculation unit, a PID control unit, and a steering actuation unit; the offset information calculation unit is used for calculating the physical state information and the positioning information; obtaining the transverse movement deviation of the vehicle, and sending the transverse movement deviation to the PID control unit; according to the invention, the vehicle is controlled in a tracking way by only using one control parameter of the transverse movement deviation (transverse movement amount), so that the vehicle can be ensured not to have mutually contradictory lever effects in the tracking running process, and the vehicle vibration caused by the control overshoot can be avoided; the tracking control of the vehicle can be made smoother.
Description
Technical Field
The invention belongs to the field of unmanned track traffic, and particularly relates to a tracking control system and a control method of a PRT vehicle.
Background
The personal rapid transit system (Personal RapidTransit, PRT for short) is a public transportation system with small traffic volume, can be used as a passenger transportation vehicle in airports, parks and scenic spots, and belongs to a novel rail transportation system. The PRT vehicle is a non-contact railway vehicle, adopts rubber wheels to run, is not constrained by a solid track, belongs to a non-complete constraint system, and has high nonlinearity. The fundamental task of autonomous vehicle tracking is to travel according to a given trajectory with as little deviation as possible, according to a given speed. Specifically, on a straight line, the device has the capability of keeping running in the center of a road, and can resist external interference factors such as crosswind and the like; the curve has the capability of smoothly passing through the curve, and the error of the off-track can be controlled to be small when the vehicle runs on uneven or differently attached road surfaces. According to the vehicle motion characteristics, the tracking control task is divided into two parts: the transverse control of the vehicle tracking track and the longitudinal control of the vehicle running speed are ensured.
The whole vehicle controller (Vehicle Control Unit, VCU for short) is used as a central control unit and is the core of the whole vehicle control system. In the PRT vehicle, the VCU plans a future driving path according to the line information acquired by the sensor, calculates the rotation angle and the rotation speed of each wheel, and releases an actuating signal to the steering motor and the hub motor, thereby realizing vehicle tracking. The tracking algorithm is a decision planning technology for vehicle operation, the VCU is the brain of the PRT vehicle, and the VCU is the main body for calculation and realization of the tracking algorithm.
In PRT vehicles, there is only one actual controllable variable in a set of steering mechanisms, the steering motor. In the prior art, two feedback variables are often used as inputs to a control system, one output variable is used to act, and in the control theory, the control mode forms an over-constraint system. Based on this, the steering control system must determine who is the primary and who is the secondary lateral movement amount (distance deviation) and heading angle deviation (angle deviation) in operation. However, there is a possibility that there are two control target conflicting postures regardless of the priority control of the traversing amount, which requires the vehicle to move leftward, i.e., to turn counterclockwise, or the priority control of the heading angle deviation, such as when the heading angle deviation is counterclockwise (ψ < 0) in fig. 1 when the vehicle is running on the right side of the track (Δy > 0), which is contradictory in eliminating the tracking deviation. Further analysis shows that when the vehicle is turned clockwise to reduce the heading angle deviation or turned counterclockwise to reduce the traversing amount, the other deviation cannot be reduced at the same time, which means that when the vehicle returns to the initial stage on the track, the residual angle deviation is always present, and then the traversing amount is continuously over-regulated in the process of eliminating the angle deviation. In the process of eliminating the angle deviation and the lateral displacement deviation, the overshoot is caused, so that the vehicle shake motion is caused. The publication number is: the chinese patent of CN112486156a proposes an automatic tracking control method that achieves tracking control of virtual rail vehicles by distance deviation and angle deviation. The virtual railway vehicle is controlled through the angle deviation and the distance deviation, so that when the vehicle returns to the initial stage on the track, the angle residual deviation is always generated, and then in the process of eliminating the angle deviation, the transverse movement amount is continuously over-regulated, so that the movement of the vehicle is unstable. In the process of eliminating the angle deviation and the lateral displacement deviation, control targets of the angle deviation and the lateral displacement deviation can be in conflict, and mutually contradictory 'lever effect' exists, so that overshoot can be caused to cause the vehicle to vibrate.
Disclosure of Invention
The invention aims at: aiming at the problems that in the prior art, the PRT vehicle is controlled through course angle deviation and traversing deviation, in the process of eliminating angle deviation and traversing deviation, control targets of the angle deviation and the traversing deviation are in conflict and have mutually contradictory lever effect, thereby causing overshoot and causing vehicle vibration movement, the tracking control system and the control method of the PRT vehicle are provided.
To achieve the above object, a first aspect of the present invention provides a tracking control system of a PRT vehicle, the control system including: the control system comprises: a positioning information acquisition unit, a vehicle information calculation unit, an offset information calculation unit, a PID control unit, and a steering actuation unit;
the positioning information acquisition unit is used for acquiring the positioning information of the current vehicle and the virtual track and sending the positioning information to the offset information calculation unit;
the vehicle information calculating unit is used for calculating physical state information of the vehicle and sending the physical state information to the offset information calculating unit;
the offset information calculation unit is used for calculating a pretightening point according to the physical state information, obtaining the transverse movement deviation of the vehicle based on the pretightening point and the positioning information, and sending the transverse movement deviation to the PID control unit;
the PID control unit is used for obtaining the shaking torque of the steering motor of the vehicle based on the lateral movement deviation;
the steering actuation unit controls the vehicle to perform steering based on the yaw torque. Further, the control system further includes: a differential control unit;
the differential control unit is used for controlling the rotation speeds of the inner side wheels and the outer side wheels when the wheels turn when the vehicle turns;
and the differential control unit acquires the physical state information, the positioning information and the current vehicle running speed fed back by the vehicle in real time, and obtains the rotating speeds of the inner wheels and the outer wheels when the vehicle turns.
Further, the offset information calculating unit is configured to calculate a pre-aiming point according to the physical state information and the positioning information, and obtain a lateral movement deviation of the vehicle based on the pre-aiming point and the predicted track information of the vehicle.
Furthermore, the positioning information acquisition unit acquires the positioning information in a camera acquisition mode, a magnetic nail navigation mode or a laser radar sensing positioning mode.
Meanwhile, a second aspect of the present invention provides a control method for the above-described tracking control system, the control method comprising:
the control method comprises the following steps:
step 3, obtaining the transverse movement deviation of the vehicle according to the physical state information and the positioning information;
step 4, PID control is carried out on the transverse movement deviation to obtain the shaking torque of the steering motor of the vehicle;
and 5, controlling the steering of the vehicle through the shaking torque.
Further, the physical state information includes: the mass of the running part of the vehicle, the moment of inertia of the running part of the vehicle, the distance between the center of the front wheel and the mass center of the vehicle and the distance between the center of the rear wheel and the mass center of the vehicle;
the step 3 comprises the following steps:
step 300: obtaining the mass m of the running part of the vehicle b Moment of inertia I of running gear bz Distance l of front wheel center to vehicle center of mass f Center distance l of rear wheel from center of mass of vehicle r The method comprises the steps of carrying out a first treatment on the surface of the And substituting the following formula to obtain the distance l between the pre-aiming point of the front wheel of the vehicle and the mass center of the vehicle gf Distance l from vehicle rear wheel pre-aiming point to vehicle mass center gr ；
Step 301: according to the distance l between the pre-aiming point of the front wheel of the vehicle and the mass center of the vehicle gf VehicleDistance l of rear wheel pre-aiming point from mass center of vehicle gr And obtaining a front wheel pre-aiming point and a rear wheel pre-aiming point with the mass center position of the vehicle, and combining the positioning information to obtain the transverse movement deviation of the vehicle.
Wherein, the front wheel pre-aiming point and the rear wheel pre-aiming point are both in the length direction of the vehicle mass point, so the distance l between the front wheel pre-aiming point and the vehicle mass center can be realized gf Distance l between vehicle rear wheel pre-aiming point and vehicle mass center gr And determining the positions of the front wheel pre-aiming point and the rear wheel pre-aiming point. The distance difference between the pre-aiming point and the pre-set track in the width direction of the vehicle is the transverse movement deviation.
Further, in the step 4, the shaking torque M of the steering motor is obtained by the following formula Ψ ；
Wherein the coefficient K P Is a proportional coefficient for adjusting the convergence speed of the traversing deviation e (t), a coefficient K D Is a differential coefficient for reducing overshoot during convergence of the traversing deviation e (t).
Further, the method further comprises:
and respectively obtaining the rotating speeds of the inner side wheels and the outer side wheels when the vehicle turns according to the physical state information, the positioning information and the current vehicle running speed fed back by the vehicle in real time.
Further, the wheel speed v on the inner side of the vehicle when the vehicle is turned is calculated according to the following formula i Wheel speed v on the outside when the vehicle is turning o ；
Wherein R is the turning radius, v is the running speed of the vehicle, and a and b are half of the transverse and longitudinal spans of the vehicle.
Further, in the step 1, the positioning information is obtained by a camera acquisition mode, a magnetic nail navigation mode, or a laser radar sensing positioning mode.
In summary, due to the adoption of the technical scheme, the beneficial effects of the invention are as follows:
1. according to the invention, the vehicle is controlled in a tracking way by only using one control parameter of the transverse movement deviation (transverse movement amount), so that the vehicle can be ensured not to have mutually contradictory lever effects in the tracking running process, and the vehicle vibration caused by the control overshoot can be avoided; the tracking control of the vehicle can be made smoother;
2. in the preferred embodiment of the invention, the speed threshold of the next time frame is designed through the geometric logic relation between the vehicle and the preset track, so that the running stability of the vehicle can be further improved, and the stability of the vehicle tracking control can be further improved.
Drawings
FIG. 1 is a schematic diagram of a control target collision situation in the prior art;
FIG. 2 is an overall architecture diagram of a tracking control system provided in an exemplary embodiment of the present invention;
FIG. 3 is an overall logic diagram of a control method provided by an exemplary embodiment of the present invention;
FIG. 4 is a schematic view of a vehicle driving state at a certain point in time in an exemplary embodiment of the present invention;
FIG. 5 is a schematic illustration of various types of vehicle steering provided by an exemplary embodiment of the present invention;
FIG. 6a is a schematic diagram of a vehicle steering implemented in one instance of an exemplary embodiment of the invention;
FIG. 6b is a schematic diagram of a vehicle steering implemented in one instance of an exemplary embodiment of the invention;
FIG. 7a is an exploded view of a vehicle steering maneuver in one instance of an exemplary embodiment of the present invention;
fig. 7b is an exploded view of a steering action of a vehicle in one instance of an exemplary embodiment of the invention.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Example 1
FIG. 2 illustrates a tracking control system for a PRT vehicle in an embodiment of the present invention, including: a positioning information acquisition unit, a vehicle information calculation unit, an offset information calculation unit, a PID control unit, and a steering actuation unit;
the positioning information acquisition unit is used for acquiring the positioning information of the current vehicle and the virtual track and sending the positioning information to the offset information calculation unit, and the positioning information acquisition unit acquires the positioning information in a camera acquisition mode, a magnetic nail navigation mode or a laser radar sensing positioning mode. The offset information calculation unit is used for calculating a pretightening point according to the physical state information, obtaining the transverse movement deviation of the vehicle based on the pretightening point and the positioning information, and sending the transverse movement deviation to the PID control unit; the vehicle information calculating unit is used for calculating physical state information of the vehicle and sending the physical state information to the offset information calculating unit; the vehicle information calculating unit can calculate the mass center position of the vehicle based on the built-in model of the unit through weight information of each part fed back by the vehicle sensor in real time.
The physical information includes: the mass of the running part of the vehicle, the moment of inertia of the running part of the swing head, the distance between the center of the front wheel and the mass center of the vehicle, the distance between the center of the rear wheel and the mass center of the vehicle and the position of the mass center of the vehicle;
the offset information calculation unit calculates the distance between the front wheel pre-aiming point of the vehicle and the vehicle mass center and the distance between the rear wheel pre-aiming point of the vehicle and the vehicle mass center based on the mass of the vehicle running part, the running part shaking moment of inertia, the distance between the front wheel center and the vehicle mass center and the distance between the rear wheel center and the vehicle mass center;
and obtaining a front wheel pre-aiming point and a rear wheel pre-aiming point according to the distance between the front wheel pre-aiming point of the vehicle and the mass center of the vehicle, the distance between the rear wheel pre-aiming point of the vehicle and the mass center of the vehicle, and combining the positioning information to obtain the transverse movement deviation of the vehicle.
And sending the traversing deviation to the PID control unit; the PID control unit is used for obtaining the shaking torque of the steering motor of the vehicle based on the lateral movement deviation; the steering operation unit controls the vehicle to perform steering based on the yaw moment, and corrects a route.
Further, the control system further includes: a differential control unit; the differential control unit is used for controlling the running speed of the vehicle when the vehicle stably runs; the differential control unit acquires the physical state information, the positioning information and the current vehicle running speed fed back by the vehicle in real time to obtain the maximum running speed of the vehicle; and controlling the running speed of the vehicle at the next moment of stable running based on the maximum running speed of the vehicle.
Further, the control system further comprises a switch for turning on or off the differential control unit.
The present embodiment also provides a control method applied to the above-mentioned tracking control system, and when a flowchart thereof is shown in fig. 3, a second aspect of the present invention provides a control method for the above-mentioned tracking control system, the control method comprising:
the step 2 specifically includes: acquiring weight information of each part fed back by a vehicle sensor in real time and parameter information stored in a memory in advance; calculating the mass center position of the vehicle based on a preset model;
step 3, according to the physical state information, the positioning information and the vehicle predicted track information fed back by the vehicle in real time, obtaining the transverse movement deviation of the vehicle; wherein the physical state information includes: the mass of the running part of the vehicle, the moment of inertia of the running part of the vehicle, the distance between the center of the front wheel and the mass center of the vehicle and the distance between the center of the rear wheel and the mass center of the vehicle;
further, the step 3 specifically includes:
step 300: obtaining the mass m of the running part of the vehicle b Moment of inertia I of running gear bz Distance l from front wheel center to vehicle center of mass f Center distance l of rear wheel from center of mass of vehicle r The method comprises the steps of carrying out a first treatment on the surface of the And substituting into:
obtaining the distance l between the pre-aiming point of the front wheel of the vehicle and the mass center of the vehicle gf Distance l from vehicle rear wheel pre-aiming point to vehicle mass center gr The method comprises the steps of carrying out a first treatment on the surface of the Wherein the vehicle running gear mass m b Moment of inertia I of running gear bz All are constant, and specific values can be obtained when the PRT vehicle leaves the factory. In the invention, the running part is a front wheel and a rear wheel; unlike available automobile, the present invention has steering wheels, i.e. front and back wheels. Combining the front and rear wheels into one running portion solves the problem of tracking of a pair of two front and rear wheels, taking the other side into account, as well as the same. For example, when a vehicle runs four wheels, the front two wheels are certainly deflected to a certain side (left or right) of each preset track at the same time, the angles are the same, and the rear wheels are the same; namely, the movement tracks of the left and right running parts are the same.
Step 301: according to the distance l between the pre-aiming point of the front wheel of the vehicle and the mass center of the vehicle gf Distance l between vehicle rear wheel pre-aiming point and vehicle mass center gr And obtaining a front wheel pre-aiming point and a rear wheel pre-aiming point with the mass center position of the vehicle, and obtaining the transverse movement deviation e (t) of the vehicle according to the preset track information of the vehicle. In this step, for example, when there are 2 steering mechanisms in the vehicleEach steering mechanism obtains sideslip deviation control by the nearest pretightening point; namely, the front wheel steering mechanism is controlled by the transverse movement deviation obtained by the front wheel pre-aiming point, and the rear wheel steering mechanism is controlled by the transverse movement deviation obtained by the rear wheel pre-aiming point;
in the invention, the front wheel pre-aiming point and the rear wheel pre-aiming point are both in the length direction of the vehicle mass point, so the distance l between the front wheel pre-aiming point and the vehicle mass point can be realized gf Distance l between vehicle rear wheel pre-aiming point and vehicle mass center gr And determining the positions of the front wheel pre-aiming point and the rear wheel pre-aiming point.
The transverse distance between the preset aiming point and the preset track when the transverse deviation is generated is the transverse deviation; the prior art is that a traversing deviation e (t) (also called a traversing amount) of a vehicle is obtained through a pre-aiming point (also called a tracking point); as shown in fig. 4, fig. 4 shows a vehicle running state diagram at a certain time; the transverse movement deviation (instantaneous value) delta y can be obtained by assuming the front wheel pre-aiming point and the rear wheel pre-aiming point as wheels to be wheel positioning points and by the wheel positioning points (pre-aiming points) and the preset running track 1 、△y 2 . The traversing deviation can be obtained from the pre-aiming point in a variety of ways in the art, only one of which is enumerated here and the remaining ways are not repeated.
Step 4, PID control is carried out on the transverse movement deviation to obtain the shaking torque of the steering motor of the vehicle; and by: formula (VI)
Obtaining the oscillating torque M of the steering motor Ψ The method comprises the steps of carrying out a first treatment on the surface of the Wherein the coefficient K P Is a proportional coefficient for adjusting the convergence speed of e (t), coefficient K D Is a differential coefficient for reducing overshoot during e (t) convergence. The PID used in this embodiment, unlike the PID control commonly used in the industry, requires only proportional (P), derivative (D) and no integral (I) control (eliminating accumulated errors) for the virtual rail vehicle. Because the control system generates a return steering motion when the vehicle is off track, no additional traversing is required when the vehicle returns to the track centerlineThe amount is used to offset steady state deviation, and if integral control exists, the vehicle can generate certain overshoot and even reverse lateral movement amount. Preferred values of the proportional coefficient and the differential coefficient in this embodiment are: k (K) P ＝4800，K D ＝4000。
And 5, controlling the steering of the vehicle through the shaking torque.
Further, the method further comprises:
and respectively obtaining the rotating speeds of the inner side wheels and the outer side wheels when the vehicle turns according to the physical state information, the positioning information and the current vehicle running speed fed back by the vehicle in real time. The wheel speed v on the inner side of the vehicle when steering is calculated according to the following formula i Wheel speed v on the outside when the vehicle is turning o ；
Wherein R is the turning radius, v is the running speed of the vehicle, and a and b are half of the transverse and longitudinal spans of the vehicle.
The vehicle transverse and longitudinal spans are the geometric parameters of the vehicle, and the geometric parameters are directly stored in the memory of the VCU of the vehicle when the vehicle leaves the factory.
Further, in the step 1, the positioning information is obtained by a camera acquisition mode, a magnetic nail navigation mode, or a laser radar sensing positioning mode.
The vehicle needs to pass through the curve, and the tire is required to drive the vehicle to swing and turn. The existing vehicles mainly have three steering modes, namely self-guiding of the vermicular sliding force of the railway vehicles, differential steering of the caterpillar tracks of the tanks, and steering angle guiding of the wheels of the automobiles. As shown in a part a of fig. 5, the guiding mechanism of the railway vehicle is creeping force guiding, a head shaking attack angle is continuously generated in the guiding process, and the wheels are accompanied with transverse movement, so that the wheels are coupled to form snaking movement; as shown in part b of fig. 5, the guiding mechanism of the tank is that the rotation speed difference on the left side and the right side generates reverse motion to form a rotation moment, the steering process does not have meandering motion, and the steering process is only turned by the relative motion of wheels on two sides, and the steering process has larger abrasion due to the lack of the effect of a steering angle; as shown in part c of fig. 5, the PRT vehicle is steered by smoothly passing the curve with the adaptive curve radius adjusting the rotational speed of the wheels on both sides after the wheel is steered in a rolling direction. The PRT vehicle can be regarded as a combination of railway vehicles and tank steering by utilizing a steering angle and a rotating speed difference through curves, wherein the steering angle is an active factor of steering, the rotating speed difference is a follow-up factor of wheel rotation angle, the speed difference is formed in a self-adaptive way based on an energy minimum principle, and the tire abrasion of the vehicle in the steering process can be reduced.
The control system and the control method provided by the invention can be understood as two parts of 'kinematic feedforward and tracking deviation feedback' as a whole. In the 'kinematic feedforward' part, the invention performs kinematic feedforward control based on the geometric relationship between the vehicle and the road to obtain the vehicle motion optimal solution range, thereby enabling the motion and tracking control of the vehicle to be smoother.
In the tracking deviation feedback part provided by the invention, in order to solve the over-constraint problem that the control system has two inputs and only one output in the existing tracking control method, the invention does not adopt a combined positioning mode of the transverse movement quantity and the course angle deviation, but adopts a tracking deviation positioning mode of the transverse movement quantity corresponding to the steering wheel one by one.
The motion of the vehicle can be decomposed into transverse movement and shaking movement through a curve, and the direct control of the tire to perform transverse movement is not realistic, so that the actuation output of the control system is realized by means of the shaking movement of the wheels, which is similar to a traditional automobile. The front pre-aiming point and the transverse movement amount of the front wheel are in linear correlation, so that the front/rear pre-aiming point tracking function is directly realized by the fact that the wheels adjacent to the front/rear pre-aiming point are respectively responsible for one-to-one correspondence. As shown in FIG. 6a, when there is a positive traversing amount (Deltay > 0) of the pre-aiming point, the tracking control system outputs a counterclockwise head-shaking moment (M) to the wheel through the running part Ψ Less than 0), the wheels are forced to rotate anticlockwise, the lateral movement amount is gradually reduced, and the wheels are straightThe amount of lateral movement to the pre-aiming point disappears Δy=0), the larger the lateral movement amount is, the larger the shaking moment of the actuation output is. Vice versa, as shown in fig. 6 b.
In the invention, the swing control torque of the wheel steering motor is not influenced by steering angle and is completely determined by the adjacent pre-aiming point: the positive traversing (Deltay > 0) produces a negative yaw moment (M) Ψ < 0), a negative traversing amount (Deltay < 0) generates a positive panning torque (M) Ψ > 0), the tracking bias of each pretighted spot position can be made to converge at the same time. Although this control lacks course angle parameters, the tracking method can eliminate the course angle deviation of the vehicle, as shown in FIG. 7a, and the opposite lateral movement delta y of the front and rear wheels is generated 1 ＜0，Δy 2 When > 0), the running part and the track have negative attack angle with the tangential direction of the intersection point, namely the course angle deviation is negative ψ < 0, and the negative traversing amount (deltay) of the front wheel is known from the mapping relation between the traversing amount and the shaking torque 1 < 0) to produce a positive shaking torque (M Ψ1 > 0), the wheel rotates clockwise, and the amount of positive lateral movement (deltay) of the rear wheel 2 < 0) to generate a negative shaking torque (M Ψ2 And less than 0), the wheels rotate anticlockwise, the front wheel and the rear wheel form a right splayed gesture in the figure, the running part swings clockwise under the action of driving force, the running part moves along the track direction, and the wheels have a tendency to return to the track. Similarly, when the heading angle deviation is positive (ψ > 0), as shown in fig. 7b, the above-mentioned physical quantities are reversed in positive and negative directions, the front and rear wheels form a "splay" posture, the running part can also run along a curve, and the wheels have the capability of eliminating the lateral movement. Since the PRT vehicle can correct the route only by steering the vehicle, in this embodiment, the analysis of the curve can be applied to the analysis of the route correction as well as the analysis of the curve.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (8)
1. A tracking control system for a PRT vehicle, the control system comprising: a positioning information acquisition unit, a vehicle information calculation unit, an offset information calculation unit, a PID control unit, and a steering actuation unit;
the positioning information acquisition unit is used for acquiring the positioning information of the current vehicle and the virtual track and sending the positioning information to the offset information calculation unit;
the vehicle information calculating unit is used for calculating physical state information of the vehicle and sending the physical state information to the offset information calculating unit;
the offset information calculation unit is used for calculating and obtaining a pretightening point according to the physical state information, obtaining the transverse movement deviation of the vehicle based on the pretightening point and the positioning information, and sending the transverse movement deviation to the PID control unit, and comprises the steps of obtaining the running part quality m of the vehicle b Moment of inertia I of running gear bz Distance l of front wheel center to vehicle center of mass f Distance l of rear wheel center to vehicle center of mass r The method comprises the steps of carrying out a first treatment on the surface of the And substituting the following formula to obtain the distance l between the pre-aiming point of the front wheel of the vehicle and the mass center of the vehicle gf Distance l from vehicle rear wheel pre-aiming point to vehicle mass center gr ；
The PID control unit is used for obtaining the shaking torque of the steering motor of the vehicle based on the lateral movement deviation;
the steering actuation unit controls the vehicle to perform steering based on the yaw torque.
2. A PRT vehicle tracking control system according to claim 1, wherein,
the physical state information includes: the mass of the running part of the vehicle, the moment of inertia of the running part of the swing head, the distance between the center of the front wheel and the mass center of the vehicle, the distance between the center of the rear wheel and the mass center of the vehicle and the position of the mass center of the vehicle;
the offset information calculation unit calculates the distance between the front wheel pre-aiming point of the vehicle and the vehicle mass center and the distance between the rear wheel pre-aiming point of the vehicle and the vehicle mass center based on the mass of the vehicle running part, the running part shaking moment of inertia, the distance between the front wheel center and the vehicle mass center and the distance between the rear wheel center and the vehicle mass center;
and obtaining a front wheel pre-aiming point and a rear wheel pre-aiming point according to the distance between the front wheel pre-aiming point of the vehicle and the mass center of the vehicle, the distance between the rear wheel pre-aiming point of the vehicle and the mass center of the vehicle, and combining the positioning information to obtain the transverse movement deviation of the vehicle.
3. The PRT vehicle tracking control system of claim 1, characterized in that the control system further comprises: a differential control unit;
the differential control unit is used for controlling the rotation speeds of the inner side wheels and the outer side wheels when the wheels turn when the vehicle turns;
and the differential control unit acquires the physical state information, the positioning information and the current vehicle running speed fed back by the vehicle in real time, and obtains the rotating speeds of the inner wheels and the outer wheels when the vehicle turns.
4. A PRT vehicle tracking control system according to any one of claims 1 to 3, characterized in that the positioning information acquiring unit acquires the positioning information by using a camera acquisition mode, a magnetic nail navigation mode, or a laser radar sensing positioning mode.
5. A control method for a tracking control system of a PRT vehicle according to any one of claims 1 to 4, characterized by comprising:
step 1, acquiring positioning information of a current vehicle and a virtual track;
step 2, acquiring and calculating physical state information of the vehicle;
step 3, obtaining the transverse movement deviation of the vehicle according to the physical state information and the positioning information;
the physical state information includes: the mass of the running part of the vehicle, the moment of inertia of the running part of the vehicle, the distance between the center of the front wheel and the mass center of the vehicle, the distance between the center of the rear wheel and the mass center of the vehicle and the vehicle;
the step 3 comprises the following steps:
step 300: obtaining the mass m of the running part of the vehicle b Moment of inertia I of running gear bz Distance l of front wheel center to vehicle center of mass f Distance l of rear wheel center to vehicle center of mass r The method comprises the steps of carrying out a first treatment on the surface of the And substituting the following formula to obtain the distance l between the pre-aiming point of the front wheel of the vehicle and the mass center of the vehicle gf Distance l from vehicle rear wheel pre-aiming point to vehicle mass center gr ；
Step 301: according to the distance l between the pre-aiming point of the front wheel of the vehicle and the mass center of the vehicle gf Distance l between vehicle rear wheel pre-aiming point and vehicle mass center gr Obtaining a front wheel pre-aiming point and a rear wheel pre-aiming point with the mass center position of the vehicle, and combining the positioning information to obtain the transverse movement deviation of the vehicle;
step 4, PID control is carried out on the transverse movement deviation to obtain the shaking torque of the steering motor of the vehicle;
in the step 4, the shaking torque M of the steering motor is obtained through the following formula Ψ ；
Wherein the coefficient K P For the proportionality coefficient, useIn adjusting convergence speed of the traversing deviation e (t), coefficient K D Is a differential coefficient and is used for reducing overshoot in the convergence process of the traversing deviation e (t);
and 5, controlling the steering of the vehicle through the shaking torque.
6. A control method according to claim 5, characterized in that the method further comprises:
and respectively obtaining the rotating speeds of the inner side wheels and the outer side wheels when the vehicle turns according to the physical state information, the positioning information and the current vehicle running speed fed back by the vehicle in real time.
7. A control method according to claim 6, wherein the wheel speed v on the inside of the vehicle when the vehicle is turned is calculated according to the following formula i With wheel speed v outside when the vehicle is turning o
Where R is the turning radius, v is the vehicle travel speed, a is half the vehicle transverse span, and b is half the vehicle longitudinal span.
8. The method according to any one of claims 5 to 7, wherein in step 1, the positioning information is obtained by a camera acquisition method, a magnetic nail navigation method, or a laser radar sensing positioning method.
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