Vehicle position determination method and device

Abstract

The invention provides a vehicle position determination method and device. The method comprises the following steps: step 1, establishing a global coordinate system and a vehicle motion model; 2, the slope variation of vehicle mass center movement is determined according to a first preset relational expression; and step 3, determining the current position of the vehicle according to the slope variation. According to the invention, the system error is reduced, and the accuracy of vehicle position prediction is improved, so that the reliability of the parking system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of parking, and in particular to a method and device for determining a vehicle position. Background Art

[0002] With the rapid development of parking technology, the method of determining the position of the vehicle has become a research object for technicians in this field. At present, the method of determining the position of the vehicle mainly obtains the mileage of the two wheels on the rear axle through the wheel speed sensor of the vehicle body system, and uses the dead reckoning method to locate the vehicle. The dead reckoning method calculates the vehicle body azimuth angle increment and the rear axle midpoint position increment through the running process of the left and right wheels in a unit time, and accumulates the vehicle body azimuth angle increment and position increment respectively, and finally obtains the position of the vehicle relative to the starting state.

[0003] However, the above method of obtaining the mileage of the two wheels on the rear axle through the wheel speed sensor of the vehicle body system will produce large errors, mainly including errors caused by system errors and signal delays, which makes the calculated vehicle position information differ greatly from the actual position information of the actual vehicle, resulting in the actual parking position of the vehicle after parking is completed. It is far from the theoretical position of the vehicle body. Summary of the invention

[0004] The present invention provides a vehicle position determination method and device, aiming to solve the defects in the prior art, reduce system errors, improve the accuracy of vehicle position prediction, and thus improve the reliability of the parking system.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] One aspect of the present invention provides a method for determining a vehicle position, comprising:

[0007] Step 1: Establish a global coordinate system and vehicle motion model;

[0008] Step 2: determining the slope change of the vehicle's center of mass motion according to the first preset relationship;

[0009] Step 3: Determine the current position of the vehicle according to the slope change.

[0010] Specifically, the step 2 includes:

[0011] Step 201, determining the steering ratio of the vehicle;

[0012] Step 202: Obtain the current rotation angle of the steering wheel, and determine the wheel rotation angle according to a preset rotation angle formula;

[0013] Step 203: Determine the slope change of the vehicle's center of mass motion according to the first preset relationship.

[0014] Specifically, the preset rotation angle formula is:

[0015] θ W =θ S / m.

[0016] Among them, θ W is the wheel rotation angle, θ S is the current rotation angle of the steering wheel, and m is the steering ratio.

[0017] Specifically, the first preset relationship is:

[0018]

[0019] Among them, Δk is the slope change, r is the wheel radius, θ W is the wheel steering angle.

[0020] Specifically, the step 3 includes:

[0021] Step 301, obtaining the initial slope and initial position of the vehicle's center of mass;

[0022] Step 302, obtaining the change of the vehicle on the x-axis of the global coordinate system;

[0023] Step 303: Determine the current position of the vehicle according to the second preset relationship.

[0024] Specifically, the second preset relationship is:

[0025]

[0026] Among them, (x c ,y c ) is the current position, (x0, y0) is the initial position, k0 is the initial slope, Δk is the slope change, and Δx is the change of the vehicle on the x-axis of the global coordinate system.

[0027] Another aspect of the present invention provides a vehicle position determination device, comprising:

[0028] A slope determination module, and a coordinate system module, a motion model module, and a position determination module connected thereto;

[0029] The coordinate system module is used to establish a global coordinate system;

[0030] The motion model module is used to establish a vehicle motion model;

[0031] The slope determination module is used to determine the slope change of the vehicle's center of mass movement;

[0032] The position determination module is used to determine the current position of the vehicle.

[0033] Specifically, the slope determination module includes:

[0034] A wheel rotation angle unit, and a steering ratio setting unit, a steering wheel angle obtaining unit, and a slope determining unit connected thereto;

[0035] The steering ratio setting unit is used to determine the steering ratio of the vehicle;

[0036] The steering wheel angle acquisition unit is used to acquire the current rotation angle of the steering wheel;

[0037] The wheel rotation angle unit is used to preset a rotation angle formula to determine the wheel rotation angle;

[0038] The slope determination unit is used to determine the slope change of the vehicle's center of mass movement.

[0039] Specifically, the location determination module includes:

[0040] A position determination unit, and an initial information acquisition unit and a component acquisition unit connected thereto;

[0041] The initial information acquisition unit is used to acquire the initial slope and initial position of the vehicle's center of mass;

[0042] The component acquisition unit is used to acquire the change amount of the vehicle on the x-axis of the global coordinate system;

[0043] The position determination unit is used to determine the current position of the vehicle.

[0044] The beneficial effects of the present invention are as follows: the present invention constructs the relationship between the steering wheel rotation angle and the wheel rotation angle by determining the steering ratio, then establishes the relationship between the wheel rotation angle and the slope change of the vehicle movement, and then determines the position coordinates of the vehicle at the next moment according to the initial position information of the vehicle. Compared with the prior art solutions, the present invention reduces the system error, improves the accuracy of vehicle position prediction, and thus improves the reliability of the parking system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of a vehicle position determination method of the present invention;

[0046] Figure 2 is a schematic diagram of a vehicle motion model of the present invention;

[0047] Figure 3 is a schematic structural diagram of a vehicle position determination device of the present invention;

[0048] Figure 4 is a structural schematic diagram of a slope determination module of the present invention;

[0049] Figure 5 It is a structural schematic diagram of the position determination module of the present invention. DETAILED DESCRIPTION

[0050] The following specifically describes the embodiments of the present invention in conjunction with the accompanying drawings, which are only for reference and illustration and do not constitute a limitation on the scope of patent protection of the present invention.

[0051] In the process described in the specification, claims or drawings of the present invention, the serial numbers of each step (such as step 10, 20, etc.) are included. The serial numbers are only used to distinguish the steps, and the serial numbers themselves do not represent any execution order. It should be noted that the descriptions such as "first" and "second" in this article are only used to distinguish the description objects, etc., and do not represent the order of precedence, nor do they mean that "first", "second", etc. are different types.

[0052] Example 1

[0053] like Figure 1 As shown, this embodiment provides a method for determining a vehicle position, including:

[0054] Step 1: Establish a global coordinate system and vehicle motion model.

[0055] In this embodiment, the origin O of the global coordinate system XOY is the center of mass of the vehicle. Figure 2 As shown, the vehicle motion trajectory can be regarded as the motion of the center of mass O on the trajectory curve l.

[0056] Step 2: Determine the slope change Δk of the movement of the vehicle mass center O according to the first preset relationship.

[0057] In this embodiment, step 2 includes:

[0058] Step 201: Determine the steering ratio m of the vehicle.

[0059] In this embodiment, the steering ratio shown is the ratio between the vehicle steering wheel rotation angle and the wheel rotation angle.

[0060] As an example of an implementable embodiment, the steering ratio m in this embodiment is 8:1.

[0061] Step 202: Get the current rotation angle θ of the steering wheel S , determine the wheel rotation angle θ according to the preset rotation angle formula W .

[0062] The rotation angle formula is a function of the steering wheel rotation angle.

[0063] In this embodiment, the preset rotation angle formula is:

[0064] θW =θ S / m.

[0065] Among them, θ W is the wheel rotation angle, θ S is the current rotation angle of the steering wheel, and m is the steering ratio.

[0066] Step 203: Determine the slope change Δk of the movement of the vehicle mass center O according to the first preset relationship.

[0067] In this embodiment, the first preset relationship is:

[0068]

[0069] Among them, Δk is the slope change, r is the wheel radius, θ W is the wheel steering angle.

[0070] Step 3: Determine the current position of the vehicle according to the slope change Δk.

[0071] In this embodiment, step 3 includes:

[0072] Step 301: Obtain the initial slope k0 and initial position (x0, y0) of the vehicle's center of mass O.

[0073] Step 302: Obtain a change Δx of the vehicle on the x-axis of the global coordinate system.

[0074] Step 303: Determine the current position of the vehicle (x c ,y c ).

[0075] In this embodiment, the second preset relationship is:

[0076]

[0077] Example 2

[0078] like Figure 3 As shown, this embodiment provides a vehicle position determination device, including:

[0079] A slope determination module, and a coordinate system module, a motion model module, and a position determination module connected thereto;

[0080] The coordinate system module is used to establish a global coordinate system;

[0081] The motion model module is used to establish a vehicle motion model;

[0082] The slope determination module is used to determine the slope change of the vehicle's center of mass movement;

[0083] The position determination module is used to determine the current position of the vehicle.

[0084] like Figure 4 As shown, in another embodiment of the present invention, the slope determination module includes:

[0085] A wheel rotation angle unit, and a steering ratio setting unit, a steering wheel angle obtaining unit, and a slope determining unit connected thereto;

[0086] The steering ratio setting unit is used to determine the steering ratio of the vehicle;

[0087] The steering wheel angle acquisition unit is used to acquire the current rotation angle of the steering wheel;

[0088] The wheel rotation angle unit is used to preset a rotation angle formula to determine the wheel rotation angle;

[0089] The slope determination unit is used to determine the slope change of the vehicle's center of mass movement.

[0090] like Figure 5 As shown, in another embodiment of the present invention, the location determination module includes:

[0091] A position determination unit, and an initial information acquisition unit and a component acquisition unit connected thereto;

[0092] The initial information acquisition unit is used to acquire the initial slope and initial position of the vehicle's center of mass;

[0093] The component acquisition unit is used to acquire the change amount of the vehicle on the x-axis of the global coordinate system;

[0094] The position determination unit is used to determine the current position of the vehicle.

[0095] The vehicle position determination device described in this embodiment is used to run the vehicle position determination method described in Example 1. Its working process is as described in Example 1 and will not be repeated here.

[0096] The above disclosure is only a preferred embodiment of the present invention, which cannot be used to limit the scope of protection of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for determining a vehicle position, characterized in that: include: Step 1: Establish a global coordinate system and vehicle motion model; Step 2: determining the slope change of the vehicle's center of mass motion according to the first preset relationship; Step 3: Determine the current position of the vehicle according to the slope change.

2. The vehicle position determination method according to claim 1, characterized in that: The step 2 comprises: Step 201, determining the steering ratio of the vehicle; Step 202: Obtain the current rotation angle of the steering wheel, and determine the wheel rotation angle according to a preset rotation angle formula; Step 203: Determine the slope change of the vehicle's center of mass motion according to the first preset relationship.

3. The vehicle position determination method according to claim 2, characterized in that: The preset rotation angle formula is: i W =θ S / m. Among them, θ W is the wheel rotation angle, θ S is the current rotation angle of the steering wheel, and m is the steering ratio.

4. The vehicle position determination method according to claim 3, characterized in that: The first preset relationship is: Among them, Δk is the slope change, r is the wheel radius, θ W is the wheel steering angle.

5. The vehicle position determination method according to claim 4, characterized in that: The step 3 comprises: Step 301, obtaining the initial slope and initial position of the vehicle's center of mass; Step 302, obtaining the change of the vehicle on the x-axis of the global coordinate system; Step 303: Determine the current position of the vehicle according to the second preset relationship.

6. The vehicle position determination method according to claim 5, characterized in that: The second preset relationship is: Among them, (x c ,y c ) is the current position, (x0, y0) is the initial position, k0 is the initial slope, Δk is the slope change, and Δx is the change of the vehicle on the x-axis of the global coordinate system.

7. A vehicle position determination device, characterized in that: include: A slope determination module, and a coordinate system module, a motion model module, and a position determination module connected thereto; The coordinate system module is used to establish a global coordinate system; The motion model module is used to establish a vehicle motion model; The slope determination module is used to determine the slope change of the vehicle's center of mass movement; The position determination module is used to determine the current position of the vehicle.

8. The vehicle position determination device according to claim 7, characterized in that: The slope determination module comprises: A wheel rotation angle unit, and a steering ratio setting unit, a steering wheel angle obtaining unit, and a slope determining unit connected thereto; The steering ratio setting unit is used to determine the steering ratio of the vehicle; The steering wheel angle acquisition unit is used to acquire the current rotation angle of the steering wheel; The wheel rotation angle unit is used to preset a rotation angle formula to determine the wheel rotation angle; The slope determination unit is used to determine the slope change of the vehicle's center of mass movement.

9. The vehicle position determination device according to claim 8, characterized in that: The location determination module comprises: A position determination unit, and an initial information acquisition unit and a component acquisition unit connected thereto; The initial information acquisition unit is used to acquire the initial slope and initial position of the vehicle's center of mass; The component acquisition unit is used to acquire the change amount of the vehicle on the x-axis of the global coordinate system; The position determination unit is used to determine the current position of the vehicle.

Images