CN112034733A - A city simulation method of quadrotor UAV based on Unity3D - Google Patents

Abstract

The invention discloses a city simulation method of a quadrotor unmanned aerial vehicle based on Unity3D, comprising the following steps: S1, building a quadrotor unmanned aerial vehicle model, sensors, urban streets, buildings, environments and human and animal models based on Maya software; S2 、 Import the Maya software model into the Unity3D software, and use the Unity3D software for real-time rendering; S3, use the physics engine in Unity3D to develop the dynamic model of the quadrotor UAV; use the dynamics model and motor characteristics of the quadrotor UAV to develop four Static model of rotor UAV; use laser and collision detection to develop ultrasonic sensor, infrared sensor, lidar sensor and camera sensor; S4, acquire sensor data, and realize the flight of quadrotor UAV in urban environment according to the given task Mission simulation. The invention has the advantages of omnidirectional simulation, flexible online modification and configuration, real-time interaction and the like.

Description

A city simulation method of quadrotor UAV based on Unity3D

technical field

The invention relates to the technical field of unmanned aerial vehicle simulation, in particular to a city simulation method of a quadrotor unmanned aerial vehicle based on Unity3D.

Background technique

With the continuous maturity of Micro-Electro-Mechanical System (MEMS) technology, the weight of the MEMS-related navigation system for UAVs has dropped significantly. At the same time, with the vigorous development of microelectronics technology, UAV technology has developed rapidly. Various consumer-grade multi-rotor drones have entered ordinary life. Various enterprise-level drones are active in various fields such as aerial photography, inspection, agriculture, disasters, meteorology, surveying and mapping, mineral exploration, and logistics. However, in the complex urban environment due to the influence of the flow of people and vehicles, there are risks and task implementation failures in UAV operations. In the process of urban UAV development, building a near-real urban environment for UAV simulation has become an urgent need to solve. The problem.

The existing solution for the simulation of quadrotor UAV is introduced in Song Kai's paper "Design and Implementation of Quadrotor UAV Simulation Training System Based on Unity3D" based on the thrust and control torque generation principle, attitude and implementation of quadrotor UAV. Position dynamics and motion laws, establish four-rotor UAV flight control laws, and realize flight control and training. However, this scheme is only used as a flight training system for a quadrotor UAV, which lacks the interaction of the environment and the development of sensors, and the model of the scheme is fixed and cannot be changed according to requirements. More importantly, the scheme is a single simulation only For the quadrotor flight training simulation, the multi-UAV cooperation and other aspects are not considered.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a Unity3D-based quadrotor unmanned aerial vehicle city simulation method capable of all-round simulation, flexible online modification and configuration, and real-time interaction.

For achieving the above object, the technical scheme provided by the present invention is:

A method for urban simulation of quadrotor UAV based on Unity3D, including the following steps:

S1. Build quadrotor UAV models, sensors, city streets, buildings, environments, and human and animal models based on Maya software;

S2. Import the Maya software model into the Unity3D software, and use the Unity3D software for real-time rendering;

S3. Use the physics engine in Unity3D to develop the dynamic model of the quad-rotor UAV; use the dynamic model and motor characteristics of the quad-rotor UAV to develop the static model of the quad-rotor UAV; use the laser and collision detection to develop ultrasonic sensors, Infrared sensors, lidar sensors and camera sensors;

S4. Combine the established urban environment, obtain sensor data, and realize the flight mission simulation of the quadrotor UAV in the urban environment according to the given task.

Further, in the step S1, the construction process of the quadrotor UAV model includes four parts: a quarter of the fuselage adopts a cylindrical basic body to stretch, shear, and move the vertices to construct an oblate sphere;

The arm part adopts a cylinder, select the connection surface of the cylinder and the connection surface of the fuselage respectively, use the bridge tool to construct the arm shape of the machine arm, and then use the extrusion and moving tools to adjust the shape of the machine arm;

The motor part is constructed with a cylinder;

The propeller adopts a cylinder, and the basic shape of the propeller is cut on the side of the cylinder by using a polygon cutting tool, and the construction of the propeller is realized by using an extrusion tool;

The tripod is constructed with two rectangles;

The laser sensor is built with two cylinders with different radii, and the camera is built with a rectangle and a cylinder;

Human and animal models are constructed using surfaces, rectangles, and cylinders.

Further, the step S2 specifically includes:

S2-1, Unity3D imports the model built by Maya software;

S2-2, setting of environmental factors of terrain construction and wind;

S2-3, the addition of model materials, the addition of collision types, and the Shade Lab language for real-time rendering environments.

Further, in the described step S3, the specific process of utilizing the physics engine in Unity3D to develop the dynamic model of the quadrotor unmanned aerial vehicle is as follows:

The dynamics model of the quadrotor UAV is:

Pulling force: F _i = _ki ω ² _i (i=1, 2, 3, 4);

第i个螺旋桨的转速平方；k _i : i-th propeller tension coefficient,

The square of the rotational speed of the i-th propeller;

Control amount: vertical lift control amount: U ₁ =F ₁ +F ₂ +F ₃ +F ₄ ;

Roll control amount: U ₂ =2(F ₁ -F ₃ );

Pitch control amount: U ₃ =2(F ₁ -F ₄ );

Yaw control amount: U ₄ =F ₁ +F ₂ -F ₃ -F ₄ ;

偏航角yaw；Rotation angle: θ: roll angle roll; Φ: pitch angle pitch;

yaw angle yaw;

d：旋翼中心到无人机坐标系x轴的垂直距离，k₁₁：横滚角速度系数，I_x：无人机x轴的转动惯量；

d: the vertical distance from the rotor center to the x-axis of the UAV coordinate system, k ₁₁ : the roll angular velocity coefficient, I _x : the moment of inertia of the UAV x-axis;

I_y：无人机y轴的转动惯量，k₂₂：俯仰角速度系数；

I _y : the moment of inertia of the y-axis of the drone, k ₂₂ : the pitch angular velocity coefficient;

I_z:无人机z轴的转动惯量，k₃₃：偏航角速度系数；

I _z : moment of inertia of the z-axis of the drone, k ₃₃ : yaw angular velocity coefficient;

Movement model:

m: mass of the drone, k _x : air resistance coefficient in the x-axis direction, _ky : air resistance coefficient in the y-axis direction, k _Z : air resistance coefficient in the z-axis direction, ɡ: gravitational acceleration coefficient;

The dynamic model of the drone utilizes rigid body simulation in the physics engine provided by Unity3D.

Further, the specific implementation process of step S4 includes the following six parts:

S4-1. Receive flight mission:

S4-2. Obtain the coordinates of the collision between the laser ray and the object and the image captured by the camera and save it;

S4-3. Use the situation sorting method to fuse the data of the IMU and each sensor, and prioritize the data collected by multiple sensors according to the weather conditions of the urban simulation scene. For example, due to rainy weather, the camera is easily disturbed by rain, so Lower the priority of camera data, and lidar data will have the highest priority. Set scoring coefficients for all priorities, and conduct reliability evaluation and fusion of collected sensor data according to the current sorting status;

S4-4. Use the dynamic model of the UAV and the PID control algorithm to control the position and attitude of the UAV, and control the UAV to reach the designated mission point;

S4-5. Judgment of the end of the flight mission;

S4-6, the drone returns.

Compared with the prior art, the principle and advantages of this scheme are as follows:

1) For the model simulation of the quad-rotor UAV, this scheme divides the quad-rotor UAV model into two parts: a dynamic model and a static model. Use the physics engine to realize the dynamic model, and use the dynamic laws and electrical characteristics to realize the static model. The fusion simulation of the two aspects will be able to fully simulate the dynamic and electrical characteristics of the quadrotor UAV.

2) For the configurability of the model, this solution integrates Maya software and Unity3D software, uses Maya software model construction and Unity model online import, realizes flexible online modification and configuration of the model, and can flexibly configure the urban simulation environment.

3) For environmental interaction, this solution uses ray and collision detection to simulate common sensors for UAVs such as ultrasonic sensors, infrared sensors, lidar sensors, camera sensors, etc., to realize the perception simulation and real-time interaction of quadrotor UAVs in urban environments.

4) In view of the single existing simulation function, this scheme modularizes the characteristics of each part of the model, such as the static model of the UAV, and the characteristics of the sensor model, and provides a configuration interface. Various modules can be used to realize various types of simulation of quadrotor UAV in urban environment.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the services required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

FIG. 1 is a flowchart of a method for urban simulation of a quadrotor UAV based on Unity3D of the present invention.

Detailed ways

Below in conjunction with specific embodiment, the present invention will be further described:

As shown in FIG. 1 , a method for simulating a city of a quadrotor UAV based on Unity3D described in this embodiment includes the following steps:

S1. Build quadrotor UAV models, sensors, city streets, buildings, environments, and human and animal models based on Maya software, including:

S11: Four-rotor UAV, sensor physical model construction;

S12: Construction of urban buildings such as buildings, street lamps, and models of urban trees, flowers, and lakes;

S13: Construction of urban human model and animal model;

More specifically, the construction process of the quadrotor UAV model consists of four parts: a quarter of the fuselage uses a cylindrical primitive to stretch, shear, and move the vertices to construct an oblate sphere;

The arm part adopts a cylinder, select the connection surface of the cylinder and the connection surface of the fuselage respectively, use the bridge tool to construct the arm shape of the machine arm, and then use the extrusion and moving tools to adjust the shape of the machine arm;

The motor part is constructed with a cylinder;

The propeller adopts a cylinder, and the basic shape of the propeller is cut on the side of the cylinder by using a polygon cutting tool, and the construction of the propeller is realized by using an extrusion tool;

The tripod is constructed with two rectangles;

The laser sensor is built with two cylinders with different radii, and the camera is built with a rectangle and a cylinder;

Human and animal models are constructed using surfaces, rectangles, and cylinders.

S2. Import the model of the Maya software into the Unity3D software, and use the Unity3D software for real-time rendering; this step specifically includes:

S2-1, Unity3D imports the model built by Maya software;

S2-2, setting of environmental factors of terrain construction and wind;

S2-3, the addition of model materials, the addition of collision types, and the Shade Lab language for real-time rendering environments.

In the above, the model import is to open the outline view in the Maya software, select the exported object, send it to Unity, and save it in the Unity project.

The construction of the terrain is to create the ground in the Unity3D software, and set the length, width, height and surface texture of the ground in the description interface of the ground. The undulation of the terrain can be set with the height brush, and the grass or pavement on the ground can be achieved with maps.

The real-time rendering of the environment is done by writing Shade Lab programs, including: Shade root command, Properties attribute command, Subshader command, Subshader Tags command, Pass command, Fallback command, Category command.

S3. Use the physics engine in Unity3D to develop the dynamic model of the quad-rotor UAV; use the dynamic model and motor characteristics of the quad-rotor UAV to develop the static model of the quad-rotor UAV; use the laser and collision detection to develop ultrasonic sensors, Infrared sensors, lidar sensors and camera sensors;

Among them, the specific process of using the physics engine in Unity3D to develop the dynamic model of the quadrotor UAV is as follows:

The dynamics model of the quadrotor UAV is:

Pulling force: F _i = _ki ω ² _i (i=1, 2, 3, 4);

第i个螺旋桨的转速平方；k _i : i-th propeller tension coefficient,

The square of the rotational speed of the i-th propeller;

Control amount: vertical lift control amount: U ₁ =F ₁ +F ₂ +F ₃ +F ₄ ;

Roll control amount: U ₂ =2(F ₁ -F ₃ );

Pitch control amount: U ₃ =2(F ₁ -F ₄ );

Yaw control amount: U ₄ =F ₁ +F ₂ -F ₃ -F ₄ ;

俯仰角pitch；

偏航角yaw；Rotation angle: θ: roll angle roll;

pitch angle pitch;

yaw angle yaw;

d：旋翼中心到无人机坐标系x轴的垂直距离，k₁₁：横滚角速度系数，I_x：无人机x轴的转动惯量；

d: the vertical distance from the rotor center to the x-axis of the UAV coordinate system, k ₁₁ : the roll angular velocity coefficient, I _x : the moment of inertia of the UAV x-axis;

I_y：无人机y轴的转动惯量，k₂₂：俯仰角速度系数；

I _y : the moment of inertia of the y-axis of the drone, k ₂₂ : the pitch angular velocity coefficient;

I_z:无人机z轴的转动惯量，k₃₃：偏航角速度系数；

I _z : moment of inertia of the z-axis of the drone, k ₃₃ : yaw angular velocity coefficient;

Movement model:

m: mass of the drone, k _x : air resistance coefficient in the x-axis direction, _ky : air resistance coefficient in the y-axis direction, k _Z : air resistance coefficient in the z-axis direction, ɡ: gravitational acceleration coefficient;

The dynamic model of the drone utilizes the rigid body simulation in the physics engine provided by Unity3D;

Laser and collision simulation Ultrasonic sensors, infrared sensors, lidar sensors, and camera sensors use ray and collision detection to get the position where the ray collides with the object in a callback function.

S4. Combine the established urban environment, obtain sensor data, and realize the flight mission simulation of the quadrotor UAV in the urban environment according to the given task. The specific process is as follows:

S4-1. Receive flight mission:

S4-2. Obtain the coordinates of the collision between the laser ray and the object and the image captured by the camera and save it;

S4-3. Use the situation sorting method to fuse the data of the IMU and each sensor, and prioritize the data collected by multiple sensors according to the weather conditions of the urban simulation scene. For example, due to rainy weather, the camera is easily disturbed by rain, so Lower the priority of camera data, and lidar data will have the highest priority. Set scoring coefficients for all priorities, and conduct reliability evaluation and fusion of collected sensor data according to the current sorting status;

S4-4. Use the dynamic model of the UAV and the PID control algorithm to control the position and attitude of the UAV, and control the UAV to reach the designated mission point;

S4-5. Judgment of the end of the flight mission;

S4-6, the drone returns.

The above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of implementation of the present invention. Therefore, any changes made according to the shape and principle of the present invention should be included within the protection scope of the present invention.

Claims (5)

1. A city simulation method of a quad-rotor unmanned aerial vehicle based on Unity3D is characterized by comprising the following steps:

s1, constructing a four-rotor unmanned aerial vehicle model, a sensor, a city street, a building, an environment, a human model and an animal model based on Maya software;

s2, importing the Maya software model into Unity3D software, and performing real-time rendering by utilizing Unity3D software;

s3, developing a dynamic model of the quad-rotor unmanned aerial vehicle by using a physical engine in the Unity 3D; developing a static model of the quad-rotor unmanned aerial vehicle by utilizing a dynamic model and motor characteristics of the quad-rotor unmanned aerial vehicle; developing an ultrasonic sensor, an infrared sensor, a laser radar sensor and a camera sensor by using laser and collision detection;

and S4, acquiring sensor data by combining the established urban environment, and realizing flight task simulation of the quad-rotor unmanned aerial vehicle in the urban environment according to a given task.

2. The city simulation method for quad-rotor unmanned aerial vehicle based on Unity3D according to claim 1, wherein in step S1, the construction process of the quad-rotor unmanned aerial vehicle model comprises four parts: one quarter of the machine body adopts a cylindrical basic body to stretch, cut and move the vertex to construct an oblate sphere;

the horn part adopts a cylinder, the connecting surface of the cylinder and the connecting surface of the machine body are respectively selected, the horn shape of the horn is constructed by using a bridging tool, and then the horn shape is adjusted by using an extruding and moving tool;

the motor part is constructed by a cylinder;

the propeller adopts a cylinder, the basic shape of the propeller is cut on the side surface of the cylinder by a polygonal cutting tool, and the propeller is constructed by an extrusion tool;

the foot rest is constructed by two rectangles;

the laser sensor is constructed by two cylinders with different radiuses, and the camera is constructed by a rectangle and a cylinder;

human and animal models are constructed using curved surfaces, rectangles and cylinders.

3. The city simulation method for quad-rotor unmanned aerial vehicles based on Unity3D according to claim 1, wherein the step S2 specifically comprises:

s2-1 and Unity3D are imported into a model constructed by Maya software;

s2-2, setting of environmental factors of terrain construction and wind power;

s2-3, adding model materials, adding collision types and rendering environment in the Shade Lab language in real time.

4. The city simulation method of quad-rotor unmanned aerial vehicle based on Unity3D according to claim 1, wherein in step S3, the specific process of developing the dynamic model of quad-rotor unmanned aerial vehicle by using the physics engine in Unity3D is as follows:

the dynamics model of the quad-rotor unmanned aerial vehicle is as follows:

tension force: f_i＝k_iω² _i(i＝1，2，3，4)；

k_i: the coefficient of tension of the ith propeller,

the square of the rotational speed of the ith propeller;

control amount: vertical lift control: u shape₁＝F₁+F₂+F₃+F₄；

Roll control amount: u shape₂＝2(F₁-F₃)；

Pitch control amount: u shape₃＝2(F₁-F₄)；

Yaw control amount: u shape₄＝F₁+F₂-F₃-F₄；

Rotation angle: θ: a roll angle roll;

a pitch angle pitch;

yaw angle yaw;

d: perpendicular distance, k, from rotor center to x-axis of coordinate system of unmanned aerial vehicle₁₁: coefficient of roll angular velocity, I_x: the rotational inertia of the x-axis of the unmanned aerial vehicle;

I_y: moment of inertia, k, of the unmanned plane y axis₂₂: pitchingAn angular velocity coefficient;

I_zrotational inertia k of the z-axis of the unmanned aerial vehicle₃₃: a yaw rate coefficient;

and (3) motion model:

m: mass of unmanned aerial vehicle, k_x: coefficient of air resistance, k, in the x-axis direction_y: coefficient of air resistance, k, in the y-axis direction_z: z-axis coefficient of air resistance, Ag: a gravitational acceleration coefficient;

the dynamic model of the drone utilizes rigid body simulations in the physics engine provided by Unity 3D.

5. The city simulation method of quad-rotor unmanned aerial vehicle based on Unity3D according to claim 1, wherein the specific implementation process of step S4 includes the following six steps:

s4-1, receiving a flight mission:

s4-2, acquiring and storing the coordinates of the collision of the laser ray and the object and the image shot by the camera;

s4-3, fusing data of the IMU and each sensor by using a situation sorting method;

s4-4, controlling the position and the posture of the unmanned aerial vehicle by using a dynamic model and a PID control algorithm of the unmanned aerial vehicle, and controlling the unmanned aerial vehicle to reach a specified task point;

s4-5, judging the ending of the flight mission;

s4-6, and returning the unmanned aerial vehicle.

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