Bridged trackless train and steering control method thereof

Abstract

The invention relates to a bridging type trackless train which comprises a plurality of vehicles, a plurality of rotary supporting devices, a plurality of bridging train bodies and a steering control unit. Wherein the vehicle running at the first position is called as a pilot vehicle, the other vehicles are called as following vehicles, and all the vehicles have a steering function; the front end and the rear end of the bridging vehicle body are installed between two adjacent vehicles through the rotary supporting devices respectively and can do yawing motion and pitching motion around the vehicles. The steering of the pilot car is manually controlled; the steering of the following vehicle is controlled by the steering control unit, so that each vehicle runs on the same track; the historical turning angle of the steering shaft of the pilot vehicle is recorded, the turning angle is transmitted to the steering shaft of each following vehicle in a delayed mode according to the distance between each following vehicle and the pilot vehicle and serves as the feedforward steering control quantity of each steering shaft, and the feedback control quantity is calculated based on the track deviation between the front vehicle and the rear vehicle to obtain the feedback steering control quantity of each steering shaft. And steering control can be efficiently and accurately carried out on each following vehicle. On the basis of ingenious combination of the leading vehicle, the bridging vehicle body, the steerable following vehicle and other components and an innovative train steering control method, train steering can be efficiently and accurately controlled, front and rear vehicles can be kept in the same track to automatically run in rows, the train motion characteristics and mechanical characteristics can be optimized, and the train steering control method is suitable for large-scale popularization and application. The sideslip and rollover risks of the train are reduced, and safe and stable operation of the trackless train is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle engineering, and in particular to a bridge-type trackless train and a steering control method thereof. Background Art

[0002] As we all know, the transportation efficiency of railway trains (trains) is dozens of times that of cars, while the transportation cost is less than one-tenth of that of cars; if trackless trains can automatically run in a line on the same track as tram trains, their transportation efficiency can be increased exponentially and transportation costs can be reduced.

[0003] In existing railway trains, the upper car body is arranged above the front and rear bogies, and the upper car body and the bogie are connected by a bolster. When the train turns, each bogie is constrained by the track and turns along the track, and each upper car body swings around the corresponding bogie along the corresponding bolster; the bogie does not have an active steering function, and its steering is controlled by the train track; and, in general, the slope and curvature of the train track are very small, and the motion relationship between the upper car body and the bogie is relatively simple. However, on the one hand, trackless trains have no tracks, and it is impossible to constrain the vehicle's steering through mechanical tracks; on the other hand, the actual operating conditions of trackless trains are more complicated, and the operating parameters such as the turning curvature, road slope, and flatness are quite different from the relevant parameters of rail trains, and there is a more complex relative motion relationship between the various components of the train. Therefore, the body structure of rail trains is difficult to transfer to trackless trains.

[0004] Existing automobile trains are generally composed of a tractor and multiple trailers, but the trailers are not equipped with steering axles. When the train is running, it is difficult for the front and rear vehicles to run on the same track. Moreover, the vehicles are connected by an articulated mechanism with only one articulated kinematic pair. Simply adding a steering axle to each trailer will change the motion model and freedom of motion of the train mechanism, making it difficult for it to run normally. Therefore, there is no mature technical solution to this problem in the prior art.

[0005] In order to make each follower vehicle in a trackless train run along the track of the lead vehicle, trajectory following control algorithms such as LQR and MPC are usually used in the prior art. This type of algorithm calculates and controls the steering angle of each follower vehicle based on the driving track of the lead vehicle. However, this type of method has problems such as large consumption of computing resources and long system delay. Patent CN105857394B, a trackless train steering control device and control method thereof, proposes a steering control method that, when each follower vehicle reaches the historical position of the first vehicle, makes its steering wheel angle equal to the historical angle of the first vehicle at the historical position. Although this method solves the problems of high computing power requirements and system delays, it is obviously an open-loop control method that lacks feedback control, which will cause the trajectory deviations of each follower vehicle to continue to accumulate.

[0006] In order to solve the above technical problems, the present invention proposes a bridge-type trackless train, which can effectively make up for the shortcomings of the prior art. After searching, no technical solutions identical or similar to the present invention were found. Summary of the invention

[0007] The purpose of the present invention is to provide a bridge-type trackless train and a steering control method thereof, which can ensure that each vehicle in the train can flexibly turn and automatically travel in a line on the same track through the optimized design of the structural device, and can also increase the load, reduce the cost, optimize the force characteristics, and ensure the safe and stable operation of the train; at the same time, solve the problems of high steering control computing power requirements, long delay and lack of feedback control in the prior art.

[0008] The specific technical solution of the present invention is a bridge-type trackless train, which is creative in that it includes a plurality of vehicles, a plurality of slewing support devices, a plurality of bridge-type vehicle bodies and a steering control unit; wherein the vehicle running in the first position is called a pilot vehicle, and the remaining vehicles are called following vehicles; All vehicles in the train have a steering function; wherein the steering of the pilot vehicle is manually controlled by the driver, and the steering of the following vehicles is controlled by the steering control unit, and each of the following vehicles is kept on the same track as the pilot vehicle.

[0009] The bridge car body is connected to two adjacent vehicles in front and behind through two sets of the front and rear slewing support devices; the function of the slewing support device is to connect the corresponding vehicle with the bridge car body and enable the bridge car body to perform relative yaw and pitch movements around the corresponding vehicle; for example, when a train enters a curve from a straight road, a yaw angle change will occur between the relevant vehicle and the bridge car body, and relative yaw movement will occur during the process; when a train enters a ramp from a horizontal road or a train travels on a bumpy road, a pitch angle change will occur between the relevant vehicle and the bridge car body, and relative pitch movement will occur during the process; the function of the slewing support device is to adapt to the above-mentioned relative movement between relevant components of the train and ensure stable operation of the train; The bridge vehicle body is also used to carry people or goods, and the specific form can be a passenger car or a freight car, or a freight chassis, a liquid storage tank body, etc.

[0010] In the horizontal projection plane, a bridge-type trackless train of the present invention can be regarded as a motion mechanism, wherein the pilot vehicle, the following vehicle, and the bridge vehicle body can be regarded as motion components, and the slewing support device and the instantaneous center of rotation speed of the vehicle can be regarded as low-pair motion pairs; assuming that the train includes a total of n vehicles, then corresponding to n-1 bridge vehicle bodies, each vehicle corresponds to a speed instantaneous center, a total of n low-pair motion pairs, and each bridge vehicle body corresponds to two slewing support devices, a total of 2 (n-1) low-pair motion pairs; according to the degree of freedom equation of the planar motion mechanism, the degree of freedom F of the train motion mechanism is: F=3(n+n-1)-2(n+2n-2)=1; It can be known from the principle of mechanism movement that if the degree of freedom of the movement mechanism is equal to the number of the driving components, the movement mechanism can maintain a coordinated and stable movement relationship; in the present invention, the degree of freedom of the train movement mechanism is 1, and its driving component is the pilot car, and the number is also 1. Therefore, the bridge-type trackless train of the present invention can obtain appropriate degrees of freedom of movement based on the ingenious structural design, has inherent stability, and can maintain a coordinated and stable movement relationship.

[0011] The bridge car body is connected to the front and rear vehicles through the front and rear two sets of the slewing support devices. During the movement of the train, the two sets of the slewing support devices often cannot run on the same track, and there is a certain degree of track deviation. The bridge car body can adapt to the track deviation through yaw movement; from the geometric relationship, it can be seen that the longer the length of the bridge car body, the smaller its yaw angle relative to the front and rear vehicles; when there is a force between the front and rear vehicles, based on the principle of force decomposition, it can be seen that the smaller the yaw angle, the smaller the lateral component of the vehicle, and the more stable the vehicle; in specific engineering practice, the actual length of the bridge car body can reach several meters, or even dozens of meters, which is usually much larger than the value of the track deviation, so that the size of the yaw angle can be effectively controlled, and then the lateral force of the vehicle can be controlled, effectively improving the stability of the vehicle and the train.

[0012] Therefore, the technical solution of connecting the front and rear vehicles through the bridge body and the slewing support device in the present invention can enable the train to obtain appropriate freedom of movement, maintain a coordinated and stable movement relationship, and improve the force characteristics of the train, thereby enhancing the safety and stability performance of the train; at the same time, since each of the following vehicles has a steering function, the steering of each of the following vehicles is controlled by the steering control unit, which can effectively control the trajectory deviation between the vehicles and make them travel on the same trajectory.

[0013] When the steering control unit is working, it first calculates the driving trajectory of the lead vehicle based on the lead vehicle coordinate system, and then controls the steering of each follower vehicle according to the trajectory deviation between each follower vehicle and the lead vehicle, so that each vehicle can travel on the same trajectory like a train.

[0014] Preferably, the pilot vehicle has multiple axles, wherein the front axle is a steering axle and the remaining axles are non-steering axles; when the bridge body is connected to the pilot vehicle, the corresponding slewing support device is located between the front axle of the pilot vehicle and any non-steering axle to ensure that the bearing force acts between the steering axle and the non-steering axle of the vehicle, thereby ensuring the stability of the vehicle.

[0015] The following vehicle has more than one non-steering axis; if the following vehicle is provided with multiple non-steering axes for reasons such as improving load-bearing capacity, each non-steering axis has a center point, and there are multiple corresponding center points. Let the geometric center of the multiple center points be O. At this time, a non-steering axis is virtualized through point O and parallel to any non-steering axis. The virtual non-steering axis is called an equivalent non-steering axis. It is not difficult for technicians in the field of vehicle engineering to understand that the motion constraint effect of the equivalent non-steering axis on the following vehicle is roughly the same as the motion constraint effect of all the non-steering axes of the following vehicle on the following vehicle; if the following vehicle has only one non-steering axis, the equivalent non-steering axis coincides with the non-steering axis.

[0016] Each following vehicle can be connected to at most two front and rear bridge bodies, corresponding to two sets of slewing support devices for connection, and the two sets of slewing support devices should be symmetrically arranged along the equivalent non-steering axis of the following vehicle; according to the principle of vehicle motion, the extension line of the equivalent non-steering axis should pass through the instantaneous center of velocity of the vehicle. Combined with simple geometric relationships, it can be seen that when the front and rear two sets of slewing support devices are symmetrically arranged along the equivalent non-steering axis, the turning radius of the two sets of slewing support devices is the same, and the corresponding motion trajectories are similar. At this time, the angle between the bridge body and the following vehicle is small; when there is a force between the bridge body and the following vehicle, its lateral component force is small, which can effectively prevent the vehicle from experiencing dangerous conditions such as wheel skidding or even rollover, thereby improving the safety and stability of the train.

[0017] Preferably, an optional technical solution for the following vehicle is that it includes multiple axles, and only the front axle has a steering function, and the remaining axles are non-steering axles, and the steering control unit controls the steering of the following vehicle by controlling the steering axle.

[0018] Preferably, the slewing support device includes a yaw bearing, a pitch axis, two pitch bearings, and two pitch bearing seats.

[0019] The pitch axis is fixed to the outer ring of the roll bearing, and its axis is orthogonal to the rotation axis of the roll bearing; the inner rings of the two pitch bearings are respectively fixed to the two sides of the pitch axis, and their outer rings are respectively fixed to the two pitch bearing seats.

[0020] Obviously, the slewing support device, based on the combined design of the yaw bearing and the pitch bearing, can adapt to both the relative yaw movement and the relative pitch movement between the bridge body and the corresponding vehicle, thereby ensuring the normal running of the train.

[0021] Preferably, a yaw angle measuring device is also installed on the slewing support device, which is used to measure the relative yaw angle between the bridge vehicle body and the corresponding vehicle, and then obtain the relative position relationship between the vehicles through the train dimension chain; the steering control unit can use the relative position relationship to obtain the trajectory deviation between each following vehicle and the pilot vehicle, and control the steering of each following vehicle accordingly, so that each vehicle travels on the same trajectory.

[0022] The yaw angle measuring device includes an angle encoder, a bracket, a coupling, and a pin; the stator of the angle encoder is fixedly mounted on the inner ring of the yaw bearing through the bracket, and the rotor of the angle encoder is connected to the pin through the coupling; the pin is fixed to the pitch axis and fixed to the outer ring of the yaw bearing through the axis; and the angle encoder and the pin are coaxial with the yaw bearing.

[0023] As mentioned above, the slewing support device can adapt to the relative yaw motion and relative pitch motion between the bridge body and the corresponding vehicle, and in fact also limits other relative motion degrees of freedom, such as relative roll motion and relative translation are constrained; the slewing support device makes the relative motion relationship between the bridge body and the corresponding vehicle relatively simple, avoiding the relative motion relationship being too complicated; it is conducive to accurately measuring the relative yaw angle between the bridge body and the corresponding vehicle and obtaining the relative position relationship between each vehicle in combination with the train dimension chain; under the existing technical conditions, the measurement accuracy of the relative yaw angle can easily reach 0.01 degrees; based on simple trigonometric geometric relationships, it can be seen that if the total length of the train is 30 meters, it includes three bridge bodies, the corresponding lateral positioning error between the vehicles is at the millimeter level, and the corresponding longitudinal positioning error can be ignored, which fully meets the centimeter-level positioning accuracy requirements of the present invention.

[0024] Preferably, another optional technical solution for the following vehicle is that the following vehicle is provided with a swing-arm steering device and one or more non-steering shafts, but no steering shaft; the steering control unit controls the steering of the following vehicle by controlling the swing of the yaw steering device; the steering of the following vehicle requires a large steering torque, and the swing-arm steering device can provide a relatively long steering arm and drive the vehicle to steer based on the lever principle; since the following vehicle does not need to be provided with a steering shaft, the vehicle cost and body weight can be greatly reduced, and the vehicle structure can be optimized, but the steering control difficulty of the corresponding steering control unit will be increased.

[0025] Preferably, the swing arm steering device includes a steering swing arm, a steering motor, a steering gear and an arc-shaped rack; the steering swing arm is columnar, and its two ends are respectively fixedly mounted on the frame of the following vehicle and the steering motor; the steering gear is fixedly mounted on the rotating shaft of the steering motor; the arc-shaped rack is fixedly mounted on the bottom of the bridging vehicle body and meshes with the steering gear.

[0026] The steering control unit controls the swing of the swing arm steering device by controlling the rotation angle of the steering motor, and controls the steering of the following vehicle.

[0027] Preferably, the bridge car body also includes a number of universal wheels; the universal wheels are installed under the bridge car body and play a supporting role, which can share the load of the rotating support device to improve the carrying capacity of the bridge car body; when the universal wheels are installed on both sides of the bridge car body, the left and right swing of the bridge car body can also be effectively controlled during the movement of the train, thereby improving the stability of the train.

[0028] The present invention also proposes a steering control method for a bridge-type trackless train; in order to control each following vehicle to travel along the trajectory of the pilot vehicle, the prior art usually adopts trajectory tracking control algorithms such as LQR and MPC, which can calculate the steering control parameters of the steering shaft of each following vehicle based on the trajectory of the pilot vehicle, such as the feedforward value and feedback value of the angle, speed, and torque, but such algorithms have complex calculation processes, large computing power requirements, and long system delays; Southwest Jiaotong University has proposed a new steering control method for trackless trains (patent CN105827394B), which attempts to record the historical angle of the steering wheel of the leading vehicle and delay the transmission of the angle to the corresponding steering shaft of the following vehicle according to the distance between each following vehicle and the pilot vehicle, and perform steering control on it accordingly. Although this method avoids the complex calculation process, it is an open-loop control method and lacks a feedback control process, which will lead to the continuous accumulation of trajectory deviations of the front and rear vehicles.

[0029] In order to overcome the above technical problems, the present invention proposes a novel steering control method for a trackless train.

[0030] Based on the classical control principle, the steering control of each following vehicle should include feedforward control and feedback control. The technical concept of the present invention is that the feedforward control does not need to be obtained by complex algorithms such as LQR and MPC, but directly uses the historical steering control parameters of the pilot vehicle and is obtained based on the distance delay between each following vehicle and the pilot vehicle; and the feedback control parameters are obtained based on the trajectory deviation between the front and rear vehicles. This can reduce computing power requirements and system delays, and can also achieve closed-loop control, improve the accuracy of trackless train steering control, and reduce the trajectory deviation between the front and rear vehicles. Specifically as follows, The steering control method of a following vehicle FV has the following steps: S1, Initial setting When the vehicles in the trackless train are in the same straight line, let the distance between the steering axis of the following vehicle FV and the steering axis of the leading vehicle be DFV; Let DS be a constant greater than 0, and define DS as the mileage step length; Assume N is a natural number, N=int(DFV / DS)+1; that is, the steering axis of the following vehicle FV differs from that of the leading vehicle by approximately N-1 mileage steps DS; when the mileage of the leading vehicle increases by N-1 mileage steps DS, the steering axis of the following vehicle FV reaches the historical position of the steering axis of the leading vehicle; Let M be a natural number, and M>N; Let DM be a sliding array of length M, which contains M vector data; each vector data includes three dimensions: angle A, speed V, and torque T, and their initial values ​​are all set to 0; let K be a natural number; let the vector value of the Kth vector data in the sliding array DM be DM[K]; S2, record the historical steering parameters of the steering axis of the pilot vehicle into the sliding array DM; When the mileage of the pilot car increases by DS, the data in the sliding array DM moves backward by one position, that is, from back to front, so that DM[K+1]=DM[K]; The steering parameters of the steering axis of the pilot vehicle K at the current moment, the three-dimensional vector (A, V, T) consisting of the steering angle A, speed V, and torque T, are recorded in the first bit of the sliding array, that is, DM[1]=(A, V, T); If the sliding array DM slides N-1 times, the value of DM[1] is transferred to the Nth bit of the sliding array DM, and its value is recorded as DM[N]. At this time, the steering shaft of the following vehicle FV should reach the position of the steering shaft of the leading vehicle at time K. Under ideal conditions, the steering control quantity such as the steering angle of the steering shaft of the following vehicle FV should be equal to DM[N], that is, equal to the steering control quantity when the steering shaft of the leading vehicle is at the same position. Under actual working conditions, due to various factors, there will be a certain deviation between the actual position of the steering shaft of the following vehicle FV and the position of the steering shaft of the leading vehicle at time K. In order to accurately control the trajectory of the following vehicle FV, a feedback control quantity should also be added when controlling the steering of its steering shaft. DM[N] is set as the feedforward control quantity of the steering shaft of the following vehicle FV. S3, based on the trajectory deviation between the following vehicle FV and the leading vehicle, calculate the feedback value SP of the steering control parameter of the steering axis of the following vehicle FV; wherein SP is also a three-dimensional vector, including three dimensions of the steering angle AP, the rotation speed VP, and the torque TP, that is, SP=(AP, VP, TP); in the prior art, the more classic feedback control quantity acquisition algorithm is the PID algorithm, and its calculation and parameter adjustment process are relatively mature, and the computing power requirement is low, and the system delay is small. The specific algorithm is a mature technology and will not be described in detail here; S4, control the steering control parameter SFV of the steering axis of the following vehicle FV, where SFV is a three-dimensional vector, including the three dimensions of the steering angle AE, the rotation speed VE and the torque TE, that is, SFV=(AE, VE, TE); SFV includes the feedforward control quantity DM[N] and the feedback control quantity SP; That is, SFV = DM[N] + SP; S5, return to S2.

[0031] The present invention proposes a novel trackless train and a steering control method thereof. Compared with the existing technical solutions, the present invention can effectively optimize the motion characteristics and force characteristics between the vehicles and the bridge bodies in the train, so that the train system can obtain appropriate motion freedom and coordinated stable motion relationship, and can effectively prevent the vehicle from skidding and rolling over, thereby ensuring the safe and stable operation of the train. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the assembly structure of a bridge-type trackless train according to the present invention; Figure 2 This is a schematic structural diagram of the following vehicle provided with a steering shaft in the present invention; Figure 3 This is a schematic diagram of a motion model of a bridge-type trackless train according to the present invention; Figure 4 When the bridge vehicle body is provided with universal wheels, a schematic structural diagram of a bridge-type trackless train of the present invention; Figure 5 This is a schematic structural diagram of the slewing support device in the present invention; Figure 6 This is a structural schematic diagram of the following vehicle provided with the swing arm steering device in the present invention; Figure 7 The present invention is a flow chart of a steering control method for a bridge-connected trackless train.

[0033] Among them: 1. Pilot vehicle, 2. Follower vehicle, 3. Slewing support device, 4. Bridge vehicle body; 21, steering axis, 22, non-steering axis, 23, equivalent non-steering axis; 31. roll bearing, 32. pitch axis, 33. pitch bearing, 34. pitch bearing seat; 41. Universal wheel; 5. Swing arm steering device, 51. Steering swing arm, 52. Steering motor, 53. Steering gear, 54. Arc rack. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with specific embodiments: Combination Figure 1 , Figure 2As shown, a bridge-type trackless train includes a plurality of vehicles, a plurality of slewing support devices 3, a plurality of bridge-type vehicle bodies 4 and a steering control unit; the vehicle in the first position is called a pilot vehicle 1, and the other vehicles are called following vehicles 2; in this embodiment, there is a pilot vehicle 1, three following vehicles 2, and three bridge-type vehicle bodies 4, and the bridge-type vehicle bodies 4 are used for loading goods and are freight carriages; The front axle of the pilot vehicle 1 is a steering axle 11, and the rear axle is a non-steering axle 12, and the steering is manually controlled by the driver; the front axle of the following vehicle 2 is a steering axle, and the steering control unit controls the steering of the following vehicle 2 by controlling the steering of the steering axle 21, so that each following vehicle 2 travels along the trajectory of the pilot vehicle 1; in order to improve the load-bearing capacity, the following vehicle 2 is provided with two non-steering axles 22, whose center points are A1 and A2 respectively, and the geometric center of A1 and A2 is set as O, and a non-steering axle is virtualized through point O and parallel to any non-steering axle 22, and the virtual non-steering axle is called an equivalent non-steering axle 23; it is not difficult for technicians in the field of vehicle engineering to understand that the motion constraint function of the equivalent non-steering axle 23 on the following vehicle 2 is substantially the same as the motion constraint effect of the two non-steering axles 22 on the following vehicle 2, so it is called an equivalent non-steering axle; The bridge body 4 is connected to the top of two adjacent vehicles in front and behind by two sets of the slewing support devices 3. When the bridge body 4 is connected to the pilot vehicle 1, the slewing support device 3 is located between the steering shaft 11 and the non-steering shaft 12 of the vehicle, so that the load of the bridge body 4 on the vehicle acts between the two shafts, thereby ensuring the stability of the vehicle. Each of the following vehicles 2 can be connected to at most two front and rear bridge bodies 4, corresponding to two sets of slewing support devices 3 for connection, and the two sets of slewing support devices 3 should be symmetrically arranged along the equivalent non-steering axis 23 of the following vehicle 2; Combination Figure 1 , Figure 2 , Figure 3 As shown, it is not difficult for technicians in the field of vehicle engineering to understand that, according to the vehicle motion model, the extension line of the equivalent non-steering shaft 23 should pass through the instantaneous center of velocity O1 of the vehicle. Combined with simple geometric relationships, it can be seen that when the front and rear sets of the slewing support devices 3 are symmetrically arranged along the equivalent non-steering shaft 23, their turning radii r1 and r2 are the same, and the corresponding motion trajectories are similar. At this time, the angles A and B between the bridge body 4 and the following car 2 are relatively small; since each following car 2 and the pilot car 1 travel on the same trajectory, the motion trajectories of the front and rear ends of the bridge body 4 connected to the pilot car 1 and the first following car 2 are similar. From the geometric relationship, it can be seen that the angle C between the bridge body 4 and the pilot car 1 is also relatively small; when there is a force between the bridge body 4 and the vehicle, for example, when the pilot car 1 brakes urgently, the lateral component of force between the bridge body 4 and the vehicle is relatively small, which can effectively prevent the vehicle from experiencing dangerous conditions such as wheel skidding or even rollover, thereby improving the safety and stability of the train.

[0035] Combination Figure 2 , Figure 4 As shown, even if the slewing support device 3 used to connect the bridge car body 4 and the vehicles is not symmetrically arranged along the equivalent non-steering axis 23, when the train turns, even if there is a track deviation between the front and rear slewing support devices 3 connected to the bridge car body 4, since the length of the bridge car body 4 is usually much larger than the track deviation, based on the geometric relationship, it can be seen that the angle between the bridge car body 4 and the front and rear vehicles will not be too large. When there is a force between the bridge car body 4 and the vehicle, its lateral component is still small, and the risk of the train sliding and rolling is also small; in addition, in order to improve the carrying capacity of the bridge car body 4 and facilitate the disassembly and assembly between the bridge car body 4 and the train, a number of universal wheels 41 are provided under the bridge car body 4; when the train is running, the universal wheels 41 only play a supporting role, do not play a motion constraint role on the train, and do not affect the normal running of the train; as shown in FIG. Figure 4 As shown, the structure of the bridge vehicle body 4 is a freight chassis. When the slewing support device 3 is arranged at the front and rear ends of each vehicle, the pilot vehicle 1 and the following vehicle 2 can also have more carrying space, thereby improving the train carrying efficiency.

[0036] The function of the slewing support device is to connect the corresponding vehicle with the bridge body and enable the bridge body to perform relative yaw motion and relative pitch motion around the corresponding vehicle; for example, when the train enters a curve from a straight road, a yaw angle change will occur between the relevant vehicle and the bridge body, and relative yaw motion will occur during the process; when the train enters a ramp from a horizontal road or the train travels on a bumpy road, a pitch angle change will occur between the relevant vehicle and the bridge body 4, and relative pitch motion will occur during the process.

[0037] like Figure 5 As shown, the slewing support device 3 includes a yaw bearing 31, a pitch axis 32, two pitch bearings 33, and two pitch bearing seats 34; The pitch axis 32 is fixed to the outer ring of the roll bearing 31, and its axis is orthogonal to the rotation axis of the roll bearing 31; the inner rings of the two pitch bearings 33 are respectively fixed to the two sides of the pitch axis 31, and their outer rings are respectively fixed to the two pitch bearing seats 34; when connecting the bridge body 4 and the vehicle, the inner ring of the roll bearing is fixed to the bridge body 4, and the outer ring of the pitch bearing 32 is fixed to the vehicle through the pitch bearing seat 34.

[0038] The slewing support device is also equipped with a yaw angle measuring device for measuring the relative yaw angle between the bridge vehicle body and the corresponding vehicle; Figure 5As shown, the yaw angle measuring device includes an angle encoder 35, a bracket 36, a coupling 37, and a pin 38; the stator of the angle encoder 35 is fixedly mounted on the inner ring of the yaw bearing 31 through the bracket 36, and the rotor of the angle encoder 35 is connected to the pin 38 through the coupling 37; the pin 38 is fixed to the pitch axis 32, and is fixed to the outer ring of the yaw bearing 31 through the axis; the angle encoder 35 and the pin 38 are both coaxial with the yaw bearing 31.

[0039] like Figure 6 As shown, another optional technical solution of the following vehicle is that the following vehicle is provided with two non-steering shafts 22 and a swing arm steering device 5, but no steering shaft, and the steering of the following vehicle is controlled by the swing arm steering device 5; the swing arm steering device 5 comprises a steering swing arm 51, a steering motor 52, a steering gear 53 and an arc-shaped rack 54; the steering swing arm 51 is columnar, and its two ends are respectively fixedly mounted on the frame of the following vehicle and the steering motor 52; the steering gear 53 is fixedly mounted on the rotating shaft of the steering motor 52; the arc-shaped rack 54 is fixedly mounted on the bottom of the bridge vehicle body 4 and meshes with the steering gear 53; The steering control unit controls the swing of the swing arm steering device 5 by controlling the rotation angle of the steering motor 52, thereby controlling the steering of the following vehicle.

[0040] The present invention also includes a steering control method for a bridge-connected trackless train; in the present invention, the pilot car is manually driven and its steering is manually controlled; the steering shaft of the pilot car is equipped with an EPS electronic assisted steering system, and when the driver performs a steering operation, the EPS provides steering assistance, and can detect and record its turning angle, speed and torque; the steering shaft of each following car is also equipped with an EPS electronic assisted steering system, and the steering of each following car can be controlled by inputting control parameters such as turning angle, speed, torque, etc. to the EPS; like Figure 7 As shown in FIG. 1 , the steering control method of a following vehicle FV in a train includes the following specific steps: S1, Initial setting When the vehicles in the trackless train are in the same straight line, let the distance between the steering axis of the following vehicle FV and the steering axis of the leading vehicle be DFV; Let DS be a constant greater than 0, and define DS as the mileage step length; Let N be a natural number, N=int(DFV / DS)+1; Let M be a natural number, and M>N; Let DM be a sliding array of length M, which contains M vector data; each vector data includes three dimensions: angle A, speed V, and torque T, and their initial values ​​are all set to 0; let K be a natural number; let the vector value of the Kth vector data in the sliding array DM be DM[K]; S2, record the historical steering parameters of the steering axis of the pilot vehicle into the sliding array DM; When the mileage of the pilot car increases by DS, the data in the sliding array DM moves backward by one position, that is, from back to front, so that DM[K+1]=DM[K]; the mileage value of the pilot car can be obtained by the odometer; At the current time K, the EPS electronic assisted steering system of the pilot vehicle reads the steering parameters of the vehicle's steering axis, including the steering angle A, speed V, and torque T, and records the three-dimensional vector (A, V, T) composed of them into the first bit of the sliding array, that is, DM[1]=(A, V, T); Set the feedforward control amount of the FV steering axis of the following vehicle to DM[N]; S3, based on the PID algorithm and the trajectory deviation between the steering axis of the following vehicle FV and the steering axis of the leading vehicle, calculate the feedback control quantity SP of the steering axis of the following vehicle FV; wherein SP is also a three-dimensional vector, including three dimensions of angle AP, speed VP, and torque TP. That is, SP = (AP, VP, TP); S4, controlling the steering control parameter SFV of the steering axis of the following vehicle FV, where SFV is a three-dimensional vector including the three dimensions of the steering angle AE, the rotation speed VE and the torque TE, that is, SFV=(AE, VE, TE); Let SFV = DM[N] + SP Send SFV to the EPS electronic assisted steering system installed on the steering shaft of the following vehicle FV, and control the steering of the vehicle; S5, return to S2.

Claims

1. A bridge-type trackless train, characterized in that: The system comprises a plurality of vehicles, a plurality of slewing support devices, a plurality of bridge vehicle bodies and a steering control unit; the vehicle in the lead is called a pilot vehicle, and the other vehicles are called following vehicles, and all vehicles have a steering function, wherein the steering of the pilot vehicle is manually controlled by a driver, and the steering of the following vehicles is controlled by the steering control unit, and each of the following vehicles is made to travel along the trajectory of the pilot vehicle; The bridge car body is connected to two adjacent vehicles in front and behind through two sets of front and rear slewing support devices; the function of the slewing support device is to connect the corresponding vehicle with the bridge car body so that the bridge car body can perform relative yaw and pitch motion around the corresponding vehicle to ensure the safe and stable operation of the train; the bridge car body is also used to carry people or goods.

2. A bridge-type trackless train according to claim 1, characterized in that: The pilot vehicle comprises a plurality of axles, wherein the front axle is a steering axle and the other axles are non-steering axles; when the bridge vehicle body is connected to the pilot vehicle, the corresponding slewing support device is arranged between the front axle and any non-steering axle of the pilot vehicle; The following vehicle has more than one non-steering axle; when the following vehicle has multiple non-steering axles, the geometric center of the center point of each non-steering axle is set to O, and a non-steering axle is virtualized through point O and parallel to each non-steering axle, and the non-steering axle is called an equivalent non-steering axle; each following vehicle can be connected to at most two of the front and rear bridge bodies, corresponding to two sets of slewing support devices for connection, and the two sets of slewing support devices should be symmetrically arranged along the equivalent non-steering axle of the following vehicle to optimize the motion characteristics and mechanical characteristics of the train.

3. A bridge-type trackless train according to claim 1, characterized in that: An optional technical solution for the following vehicle is that it includes multiple axles, and only the front axle has a steering function, and the other axles are non-steering axles. The steering control unit realizes steering control of the following vehicle by controlling the steering of the steering axle.

4. A bridge-type trackless train according to claim 1, characterized in that: The slewing support device includes a yaw bearing, a pitch axis, two pitch bearings, and two pitch bearing seats; The pitch axis is fixed to the outer ring of the roll bearing, and its axis is orthogonal to the rotation axis of the roll bearing; the inner rings of the two pitch bearings are respectively fixed to the two sides of the pitch axis, and their outer rings are respectively fixed to the two pitch bearing seats.

5. A bridge-type trackless train according to claim 4, characterized in that: A yaw angle measuring device is also installed on the slewing support device, which is used to measure the relative yaw angle between the bridge body and the corresponding vehicle; the yaw angle measuring device includes an angle encoder, a bracket, a coupling, and a pin; the stator of the angle encoder is fixedly mounted on the inner ring of the yaw bearing through the bracket, and the rotor of the angle encoder is connected to the pin through the coupling; the pin is fixed to the pitch axis and fixed to the outer ring of the yaw bearing through the axis.

6. A bridge-type trackless train according to claim 1, characterized in that: The bridge vehicle body also includes a plurality of universal wheels; the universal wheels are installed under the bridge vehicle body and play a supporting role to improve its carrying capacity and increase its stability.

7. A bridge-type trackless train according to claim 1, characterized in that: Another optional technical solution for the following vehicle is that the following vehicle is provided with a swing arm steering device and one or more non-steering shafts, but no steering shaft; and the steering control unit controls the steering of the following vehicle by controlling the swing of the swing arm steering device.

8. A bridge-type trackless train according to claim 7, characterized in that: The swing arm steering device comprises a steering swing arm, a steering motor, a steering gear and an arc-shaped rack; the steering swing arm is columnar, and its two ends are respectively fixedly mounted on the frame of the following vehicle and the steering motor; the steering gear is fixedly mounted on the rotating shaft of the steering motor; the arc-shaped rack is fixedly mounted on the bottom of the bridge vehicle body and meshes with the steering gear; The steering control unit controls the swing of the swing arm steering device by controlling the rotation angle of the steering motor, and controls the steering of the following vehicle.

9. A steering control method for a bridge-connected trackless train based on any one of claims 1 to 6, characterized in that: Steering control method of a following vehicle FV; According to the control principle, the steering control quantity of the FV steering axis of a following vehicle should be composed of feedforward control quantity and feedback control quantity. The specific steps are as follows: S1, Initial setting When the vehicles in the trackless train are in the same straight line, let the distance between the steering axis of the following vehicle FV and the steering axis of the leading vehicle be DFV; Let DS be a constant greater than 0, and define DS as the mileage step length; Let N be a natural number, N=int(DFV / DS)+1; Let M be a natural number, and M>N; Let DM be a sliding array of length M, which contains M vector data; each vector data includes three dimensions: angle A, speed V, and torque T, and their initial values ​​are all set to 0; let K be a natural number; let the vector value of the Kth vector data in the sliding array DM be DM[K]; S2, record the historical steering parameters of the steering axis of the pilot vehicle into the sliding array DM; When the mileage of the pilot car increases by DS, the data in the sliding array DM moves backward by one position, that is, from back to front, so that DM[K+1]=DM[K]; The steering parameters of the steering axis of the pilot vehicle at the current time K, the three-dimensional vector (A, V, T) consisting of the steering angle A, speed V, and torque T, are recorded in the first bit of the sliding array, that is, DM[1]=(A, V, T); Set the feedforward control amount of the FV steering axis of the following vehicle to DM[N]; S3, based on the trajectory deviation between the following vehicle FV and the leading vehicle, calculate the feedback value SP of the steering control parameter of the steering axis of the following vehicle FV; wherein SP is also a three-dimensional vector, including three dimensions of the steering angle AP, the rotation speed VP, and the torque TP, That is, SP = (AP, VP, TP); S4, controlling the steering control parameter SFV of the steering axis of the following vehicle FV, where SFV is a three-dimensional vector including the three dimensions of the steering angle AE, the rotation speed VE and the torque TE, that is, SFV=(AE, VE, TE); Let SFV = DM[N] + SP; S5, return to S2.

Images