阅读说明：本技术 一种车载式无人机自主充电平台 (Vehicle-mounted unmanned aerial vehicle autonomous charging platform ) 是由 张毅超 张真睿 汪菊南 尹一凡 诸兵 于 2021-08-10 设计创作，主要内容包括：本发明公开了一种车载式无人机自主充电平台,属于无人机技术领域；包括车顶机库,在其内安装的起降凸台和四旋翼无人机,以及无人机和起降凸台配套的充电接口装置,且起降凸台底部设有电磁铁阵列,用于紧紧吸附无人机支腿；所述无人机包括控制器,控制器分为位置控制器和姿态控制器,通过计算无人机产生的合外力大小和合外力矩分别控制无人机的位置镇定和姿态稳定；在该自主充电平台还搭有电路系统,无人机充电时,控制器每隔0.1s测量电压,间接获得充电电路的通断信息,如果充电电路断开,控制器控制无人机重新调整位姿,直至充电线路重新闭合继续充电。本发明降低了对无人机位姿精准度的要求,提高了自主降落的鲁棒性和成功率。(The invention discloses a vehicle-mounted unmanned aerial vehicle autonomous charging platform, belonging to the technical field of unmanned aerial vehicles; the unmanned aerial vehicle landing system comprises a vehicle roof hangar, a take-off and landing boss and a quad-rotor unmanned aerial vehicle which are arranged in the vehicle roof hangar, and a charging interface device matched with the unmanned aerial vehicle and the take-off and landing boss, wherein an electromagnet array is arranged at the bottom of the take-off and landing boss and used for tightly adsorbing legs of the unmanned aerial vehicle; the unmanned aerial vehicle comprises a controller, the controller is divided into a position controller and an attitude controller, and the position stabilization and the attitude stabilization of the unmanned aerial vehicle are respectively controlled by calculating the closed external force and the closed external moment generated by the unmanned aerial vehicle; the circuit system is also arranged on the autonomous charging platform, when the unmanned aerial vehicle is charged, the controller measures voltage every 0.1s to indirectly obtain on-off information of the charging circuit, and if the charging circuit is disconnected, the controller controls the unmanned aerial vehicle to readjust the pose until the charging circuit is closed again to continue charging. The invention reduces the requirement on the pose accuracy of the unmanned aerial vehicle and improves the robustness and the success rate of autonomous landing.)

1. A vehicle-mounted unmanned aerial vehicle autonomous charging platform is characterized by specifically comprising a vehicle roof hangar and a take-off and landing boss, a quad-rotor unmanned aerial vehicle and a charging interface device which are arranged in the vehicle roof hangar;

the top of the take-off and landing boss and the bottom of the unmanned aerial vehicle are respectively provided with a male connector and a female connector of a charging interface device, and when the quad-rotor unmanned aerial vehicle stops on the take-off and landing boss, autonomous charging is carried out; meanwhile, the charging interface adopts a partition conductive design; the positive electrode area and the negative electrode area are symmetrically distributed and are respectively provided with a conductive area and an insulating area; wherein the positive electrode area of the female head is 135-degree conductive and 45-degree insulating, and the conductive area of the male head is complementary with the conductive area; and vice versa;

the top of the take-off and landing boss is provided with a characteristic marker for image recognition, and the characteristic marker is used for visual positioning of the tail end of the quad-rotor unmanned aerial vehicle; the bottom of the unmanned four-rotor plane is provided with an annular groove for fixing the position of the landing leg of the unmanned four-rotor plane; an electromagnet array is arranged in the annular groove and used for adsorbing the unmanned aerial vehicle supporting legs with iron sheets, so that male and female heads of the charging device are in full contact, and the charging efficiency is ensured;

the quad-rotor unmanned aerial vehicle comprises a controller, wherein the controller is divided into a position controller and an attitude controller;

the position controller is as follows:

f is the magnitude of the resultant external force generated by the quad-rotor unmanned aerial vehicle; k is a radical of_xA feedback coefficient that is a position tracking error; e.g. of the type_xIs the position tracking error; k is a radical of_vA feedback coefficient that is a velocity tracking error; e.g. of the type_vIs the velocity tracking error; k is a radical of_iA feedback coefficient that is a tracking error; e.g. of the type_iAn integral term for the tracking error; sat_σIs a saturation function;for the ground inertial frameA third shaft;second derivative of the ideal position signal; r is a rotation matrix of the quad-rotor unmanned aerial vehicle and is a unit orthogonal matrix;

the attitude controller is as follows:

m is a combined external moment generated by the quad-rotor unmanned aerial vehicle; k is a radical of_RFeedback coefficients for attitude tracking errors; e.g. of the type_RIs the attitude tracking error; k is a radical of_ΩA feedback coefficient being an angular velocity tracking error; e.g. of the type_ΩIs the angular velocity tracking error; k is a radical of_IFeedback coefficients for attitude tracking errors; e.g. of the type_IAn integral term of the attitude tracking error; r_cIs a desired attitude matrix; omega_cA desired angular velocity; j is a rotational inertia matrix of the quad-rotor unmanned aerial vehicle;

when the quad-rotor unmanned aerial vehicle charges, the controller measures voltage every 0.1s to indirectly obtain on-off information of the charging circuit, and if the charging circuit is disconnected, the controller controls the unmanned aerial vehicle to readjust the pose until the charging circuit is closed again to continue charging.

2. The vehicle-mounted unmanned aerial vehicle autonomous charging platform of claim 1, wherein a storage battery is further arranged in the vehicle roof hangar to provide power for the take-off and landing bosses.

3. The vehicle-mounted unmanned aerial vehicle autonomous charging platform of claim 1, wherein the charging interface device is in an inverted cone shape, and a rubber cushion pad is installed at a cone tip.

4. The vehicle-mounted unmanned aerial vehicle autonomous charging platform of claim 1, wherein the lifting bosses have an outer shape conforming to an inner contour of the four-rotor unmanned aerial vehicle legs, and no gap is formed, so that the unmanned aerial vehicle can be firmly parked on the bosses.

5. The vehicle-mounted unmanned aerial vehicle autonomous charging platform of claim 1, wherein a circuit system of the autonomous charging platform comprises a power module, a communication module, an electromagnet array module, a control module and a unmanned aerial vehicle-lithium battery load;

the communication module is a communication medium between the control module and the quad-rotor unmanned aerial vehicle; the control module controls the electromagnet array module to be switched on and off according to the charging condition of the quad-rotor unmanned aerial vehicle;

the control module takes Arduino UNO as a main control board, a pin GND of the UNO is connected with the negative pole of 5v direct-current voltage of the power module, and a pin Vin is connected with the positive pole of 5v direct-current voltage; the analog pins A0 and A1 are respectively connected with two ends of the small resistor R1; the digital pin D0 is connected to the input anode of the electromagnet array module, pin D1 is connected to the input port of the communication module, pin D2 is connected to the output port of the communication module, and the UNO is grounded to the electromagnet array module and the communication module.

6. The vehicle-mounted unmanned aerial vehicle autonomous charging platform of claim 5, wherein the specific process of the circuit system for charging the quad-rotor unmanned aerial vehicle is as follows:

firstly, when the quad-rotor unmanned aerial vehicle stops on a take-off and landing boss for autonomous charging, the communication module outputs a high-level signal of 'request for charging', and the high-level signal is transmitted to a main control board UNO of the control module through a digital pin D2;

then, the master control board UNO calculates the voltage difference value between two ends of a small resistor R1 read in from the pins A0 and A1, judges whether the voltage difference value is 0, and if the voltage difference value is 0, the situation that the female head and the male head are in poor contact or in reverse connection is indicated, sends a non-contact low-level signal to the communication module from the D1 port of the digital pin to indicate the unmanned aerial vehicle to readjust the pose; otherwise, the voltage difference is not 0, which indicates that the female head and the male head are in good contact and are not reversely connected, namely, the lithium battery of the unmanned aerial vehicle is connected into the charging circuit, and then the charging is started; meanwhile, the UNO sends an electrifying signal to the electromagnet array module through the pin D0, and the electromagnet array firmly adsorbs the unmanned aerial vehicle;

when the unmanned aerial vehicle finishes charging or artificially interrupts charging, the communication module sends a low level signal of 'stopping charging', and the low level signal is transmitted to the main control panel UNO through a digital pin D2; the UNO sends a power-off signal to the electromagnet array module through a pin D0, and the electromagnet array stops working; after the electromagnet array module is demagnetized, the main control board UNO sends a 'takeoff enabling' signal to the communication module through the pin D1, and then the unmanned aerial vehicle freely takes off and lands.

Technical Field

The invention belongs to the technical field of unmanned aerial vehicles, and particularly relates to a vehicle-mounted unmanned aerial vehicle autonomous charging platform.

Background

In recent years, unmanned aerial vehicles are more and more widely applied in production and life, such as pesticide spraying, logistics dispatching, military investigation and other fields; however, the unmanned aerial vehicle generally has the problem of short endurance time, so that the development of an autonomous charging technology of the unmanned aerial vehicle is necessary.

Existing autonomous charging devices can be classified into wireless type and contact type; the mechanical structure required by the wireless charging mode is simple, but the charging efficiency is low; the contact charging mode has high efficiency, but needs a more complex mechanical structure and has higher requirement on positioning accuracy.

Simultaneously, current unmanned aerial vehicle charging device most charges for fixed base station, and this type of basic station is often bulky, is restricted by the position of basic station simultaneously, and unmanned aerial vehicle comes and goes the in-process of basic station and wastes a large amount of electric energy, therefore adaptability and flexibility are relatively poor. And vehicular charging device can compensate these defects, and the device is small can place in the roof, consequently has very strong flexibility, provides the charging platform that removes to the unmanned aerial vehicle of field work, reduces unnecessary electric energy waste.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the vehicle-mounted unmanned aerial vehicle autonomous charging platform which is used for flexibly charging the unmanned aerial vehicle and has high efficiency.

The vehicle-mounted unmanned aerial vehicle autonomous charging platform comprises a vehicle roof hangar, a take-off and landing boss, a charging interface device and a quad-rotor unmanned aerial vehicle;

the car roof hangar is internally provided with a take-off and landing boss and a storage battery, and the storage battery provides a power supply for the take-off and landing boss; the top of the take-off and landing boss and the bottom of the unmanned aerial vehicle are respectively provided with a male connector and a female connector of a charging interface device, and when the quad-rotor unmanned aerial vehicle stops on the take-off and landing boss, autonomous charging is carried out; the charging interface device is in an inverted cone shape, and a rubber cushion pad is arranged at the conical tip;

meanwhile, the charging interface adopts a partition conductive design; the positive electrode area and the negative electrode area are symmetrically distributed and are respectively provided with a conductive area and an insulating area; the positive (negative) electrode area of the female head is 135 degrees conductive and 45 degrees insulating, and the conductive (insulating) area of the male head is complementary with the conductive (insulating) area.

The top of the take-off and landing boss is provided with a characteristic marker for image recognition, and the characteristic marker is used for visual positioning of the tail end of the quad-rotor unmanned aerial vehicle;

the appearance of the take-off and landing boss is consistent with the inner contour of the four-rotor unmanned aerial vehicle support leg, no gap exists, and the unmanned aerial vehicle can be guaranteed to be firmly stopped on the boss.

The bottom of the lifting boss is provided with an annular groove for fixing the position of the landing leg of the quad-rotor unmanned aerial vehicle; the electromagnet array is arranged in the annular groove and used for adsorbing the unmanned aerial vehicle supporting legs with the iron sheets, so that the male heads and the female heads of the charging device are in full contact, and the charging efficiency is guaranteed.

The quad-rotor unmanned aerial vehicle comprises a controller, wherein the controller is divided into a position controller and an attitude controller;

the position controller is as follows:

f is the magnitude of the resultant external force generated by the quad-rotor unmanned aerial vehicle and is used for realizing position stabilization; k is a radical of_xA feedback coefficient that is a position tracking error; e.g. of the type_xIs the position tracking error; k is a radical of_vA feedback coefficient that is a velocity tracking error; e.g. of the type_vIs the velocity tracking error; k is a radical of_iA feedback coefficient that is a tracking error; e.g. of the type_iAn integral term for the tracking error; sat_σIs a saturation function;for the ground inertial frameA third shaft;second derivative of the ideal position signal; r is a rotation matrix of the quad-rotor unmanned aerial vehicle and is a unit orthogonal matrix;

the attitude controller is as follows:

m is a combined external moment generated by the quad-rotor unmanned aerial vehicle; k is a radical of_RFeedback coefficients for attitude tracking errors; e.g. of the type_RIs the attitude tracking error; k is a radical of_ΩA feedback coefficient being an angular velocity tracking error; e.g. of the type_ΩIs the angular velocity tracking error; k is a radical of_IFeedback coefficients for attitude tracking errors; e.g. of the type_IAn integral term of the attitude tracking error; r_cIs a desired attitude matrix; omega_cA desired angular velocity; j is four rotor unmanned aerial vehicle's inertia matrix.

The circuit system of the vehicle-mounted unmanned aerial vehicle autonomous charging platform comprises a power supply module, a communication module, an electromagnet array module, a control module and an unmanned aerial vehicle-lithium battery load;

the communication module is a communication medium between the control module and the quad-rotor unmanned aerial vehicle; the control module controls the on-off of the electromagnet array module according to the charging condition of the quad-rotor unmanned aerial vehicle.

The control module takes Arduino UNO as a main control board, a pin GND of the UNO is connected with the negative pole of 5v direct-current voltage of the power module, and a pin Vin is connected with the positive pole of 5v direct-current voltage; the analog pins A0 and A1 are respectively connected with two ends of the small resistor R1; the digital pin D0 is connected to the input anode of the electromagnet array module, pin D1 is connected to the input port of the communication module, pin D2 is connected to the output port of the communication module, and the UNO is grounded to the electromagnet array module and the communication module.

When the quad-rotor unmanned aerial vehicle charges, the controller measures voltage every 0.1s to indirectly obtain on-off information of the charging circuit, and if the charging circuit is disconnected, the controller controls the unmanned aerial vehicle to readjust the pose until the charging circuit is closed again to continue charging.

The specific working process is as follows:

firstly, when the quad-rotor unmanned aerial vehicle stops on a take-off and landing boss for autonomous charging, the communication module outputs a high-level signal of 'request for charging', and the high-level signal is transmitted to a main control board UNO of the control module through a digital pin D2;

then, the master control board UNO calculates the voltage difference value between two ends of a small resistor R1 read in from the pins A0 and A1, judges whether the voltage difference value is 0, and if the voltage difference value is 0, the situation that the female head and the male head are in poor contact or in reverse connection is indicated, sends a non-contact low-level signal to the communication module from the D1 port of the digital pin to indicate the unmanned aerial vehicle to readjust the pose; otherwise, the voltage difference is not 0, which indicates that the female head and the male head are in good contact and are not reversely connected, namely, the lithium battery of the unmanned aerial vehicle is connected into the charging circuit, and then the charging is started; meanwhile, the UNO sends an electrifying signal to the electromagnet array module through the pin D0, and the electromagnet array firmly adsorbs the unmanned aerial vehicle.

When the unmanned aerial vehicle finishes charging or artificially interrupts charging, the communication module sends a low level signal of 'stopping charging', and the low level signal is transmitted to the main control panel UNO through a digital pin D2; the UNO sends a "power off" signal to the electromagnet array module via pin D0 and the electromagnet array stops operating. After the electromagnet array module is demagnetized, the main control board UNO sends a 'takeoff enabling' signal to the communication module through the pin D1, and then the unmanned aerial vehicle freely takes off and lands.

The invention has the following advantages:

1) the vehicle-mounted unmanned aerial vehicle autonomous charging platform has the advantages of being capable of being carried on various vehicle types, strong in universality and capable of achieving quick maneuvering deployment, and a vehicle roof hangar is based on a vehicle-mounted trunk.

2) The vehicle-mounted unmanned aerial vehicle autonomous charging platform is characterized in that the charging interface device has a special appearance and an electrode partition design, the requirement on the pose accuracy of the unmanned aerial vehicle is lowered, the rigor of the docking condition of the charging device is lowered, and the robustness and the success rate of autonomous landing are improved.

3) Compared with a wireless charging device, the charging device has higher charging efficiency; compared with a contact plug-in type, the novel butt joint device is small in size, simple in butt joint action, high in reliability and long in service life, and a complex mechanism is avoided.

4) The utility model provides a vehicular unmanned aerial vehicle is charging platform independently, charging circuit's design can prevent positive negative pole reversal, has improved the security of charging process.

5) The utility model provides a vehicular unmanned aerial vehicle platform that independently charges, charging circuit's design can realize the real-time supervision to the charged state, can independently judge to charge unusually and make unmanned aerial vehicle readjust the position appearance, and is closed again until the charging circuit, has improved the success rate and the intelligent level of independently charging.

6) The vehicle-mounted unmanned aerial vehicle autonomous charging platform adopts the unmanned aerial vehicle control algorithm based on the nonlinear model of the four-rotor system, avoids errors caused by local linear approximation of a conventional method, and solves the control problem of a large attitude angle.

7) The utility model provides a vehicular unmanned aerial vehicle is platform that independently charges, external interference external force and the outer moment of interference have fully been introduced to unmanned aerial vehicle control algorithm, have stronger interference killing feature for unmanned aerial vehicle can adapt to the complicated external environment when descending.

Drawings

Fig. 1 is a schematic structural diagram of a vehicle-mounted unmanned aerial vehicle autonomous charging platform according to the present invention;

fig. 2 is a schematic diagram of a take-off and landing boss adopted by the vehicle-mounted unmanned aerial vehicle autonomous charging platform;

fig. 3 is a top view of a take-off and landing boss adopted by the vehicle-mounted unmanned aerial vehicle autonomous charging platform of the present invention;

fig. 4 is a schematic diagram of a charging device adopted by the vehicle-mounted unmanned aerial vehicle autonomous charging platform of the invention;

fig. 5 is a schematic diagram of a female head of a charging device adopted by the vehicle-mounted unmanned aerial vehicle autonomous charging platform of the invention;

FIG. 6 is a schematic diagram of a circuit system employed by the vehicle-mounted autonomous charging platform of the present invention;

fig. 7 is a flowchart of the operation of the control module in the circuit of the vehicle-mounted autonomous charging platform according to the present invention;

fig. 8 is a schematic diagram of a dynamic model of a four-rotor built by the invention.

Detailed Description

The invention will be described in further detail below with reference to the drawings and examples of embodiment.

The invention relates to a vehicle-mounted unmanned aerial vehicle autonomous charging platform, which comprises a vehicle roof hangar 1, a take-off and landing boss 4, a charging interface device 5 and a quad-rotor unmanned aerial vehicle 3, wherein the vehicle roof hangar is provided with a plurality of charging interfaces;

the car roof hangar 1 is internally provided with a take-off and landing boss 4 and a storage battery 2, and the storage battery 2 provides a power supply for the take-off and landing boss 4; male joint 5-1 and female joint 5-2 of the interface arrangement that charges are arranged respectively to take off and land 4 tops of boss and 3 bottoms of unmanned aerial vehicle, and the complete match of public female appearance profile for the two can in close contact with, guarantee that four rotor unmanned aerial vehicle 3 berths the reliability of independently charging on take off and land boss 4. The car roof hangar bottom plate 1-3 is arranged with electric and data circuit, and is equipped with corresponding interface to connect with the inside of the car.

The car roof garage 1 is based on a car roof luggage box, a top cover of the car roof garage is divided into a front part 1-2 and a rear part 1-1, and the front part 1-2 and the rear part 1-1 are respectively opened and closed by adopting a rotary type and a pull-slide type, as shown in figure 1. Front top cover 1-2 adopts "rotation type" to open, until perpendicular with bottom plate 1-3, blocks the disorderly air current in roof for unmanned aerial vehicle, improves pneumatic environment, reduces the interference of wind field to unmanned aerial vehicle. The rear top cover 1-1 is opened in a sliding mode, so that the flying space of the unmanned aerial vehicle and the sight line of a camera are not shielded, and the visual identification of the unmanned aerial vehicle during flying and landing is facilitated.

The roof hangar 1 can be installed on the tops of various vehicles, can be detached when not in use, and has the characteristic of modularization. The car roof hangar is divided into a closed state and an opened state, and when the unmanned aerial vehicle is parked in the car roof hangar for charging, the hangar is closed; when the unmanned aerial vehicle takes off and lands, the hangar is opened.

When the quad-rotor unmanned aerial vehicle 3 stops on the lifting boss 4, autonomous charging is carried out; the charging interface device 5 is in a reverse taper shape, when the unmanned aerial vehicle 3 independently lands, if the position slightly deviates from the position right above the lifting boss 4, the male head 5-1 on the unmanned aerial vehicle 3 can slide into the center along the conical wall of the female head 5-2 by means of gravity, the requirement on position accuracy is lowered, and the fault tolerance is improved. The taper point of the charging interface device 5 is provided with a rubber cushion pad, so that the impact force during butt joint of the male connector and the female connector is reduced.

As shown in fig. 2, the outer contour of the landing boss 4 is consistent with the inner contour of the unmanned aerial vehicle leg 3-1, and no gap exists, so that the unmanned aerial vehicle 3 can be firmly stopped on the landing boss 4. The bottom of the take-off and landing boss 4 is provided with an annular groove 4-1, so that the unmanned aerial vehicle supporting legs 3-1 can be clamped in the annular groove, and the positions of the unmanned aerial vehicle supporting legs are further fixed.

As shown in fig. 3, electromagnet arrays 4-2 (only one is marked in fig. 3) are arranged under the annular groove 4-1, and can be firmly attached to iron sheets on the unmanned aerial vehicle supporting legs 3-1, so that the male heads 5-1 and the female heads 5-2 are fully contacted. Prevent because the vehicle jolts, unmanned aerial vehicle 3 breaks away from take-off and landing boss 4. The electromagnet 4-2 is of a power-off magnetic type, when the unmanned aerial vehicle stops, the electromagnet is magnetic without being electrified, and when the unmanned aerial vehicle takes off, the electrified magnetism disappears, so that power loss is reduced.

As shown in fig. 3, a characteristic marker 4-3 for image recognition is arranged at the top of the landing boss 4, and is used for guiding the visual navigation and positioning of the tail end of the unmanned aerial vehicle. After the characteristic markers are shot by an airborne camera of the unmanned aerial vehicle, the relative position and the posture of the unmanned aerial vehicle and the take-off and landing boss are judged through a machine vision algorithm, and the unmanned aerial vehicle is guided to be aligned to the center and land.

As shown in fig. 4 and 5, the charging interface adopts a special partition conductive design; the positive electrode area and the negative electrode area are symmetrically distributed and are respectively provided with a conductive area and an insulating area; the positive (negative) electrode area of the male head is electrically conductive at 45 degrees, the rest part of the male head is insulated, and the conductive (insulated) area of the female head is complementary with the conductive (insulated) area of the female head. The positive (negative) pole area of the female head has 135 degrees of conduction and 45 degrees of insulation, and the conductive (insulation) area of the male head is complementary with the conductive (insulation) area. The positive (negative) pole of the male head and the positive (negative) pole of the female head can be charged as long as a contact area exists, so that the unmanned aerial vehicle has forward and reverse 90-degree angle redundancy, the rigor of the butt joint condition is reduced, and the fault tolerance is greatly improved.

In order to improve the safety and the intelligence level of the autonomous charging process, a circuit system is designed, as shown in fig. 6, and comprises a power supply module, a communication module, an electromagnet array module, a control module and an unmanned aerial vehicle-lithium battery load;

the power module provides 4.2v direct current voltage for unmanned aerial vehicle lithium battery charging, provides 5v direct current voltage simultaneously and supplies power for control module, communication module and electromagnetism array module. The input end of the power supply module is a 12v storage battery, and the +5v direct-current voltage is output through the LM2596 DC-DC voltage transformation module; then the DC voltage of 4.2v and the maximum charging current of 1A are output through a TP4560 lithium battery charging module.

The communication module is a communication medium between the control module and the quad-rotor unmanned aerial vehicle;

the control module controls the on-off of the electromagnetic array (electromagnet rated voltage +5v) according to the charging condition of the quad-rotor unmanned aerial vehicle. When the unmanned aerial vehicle is charged on the take-off and landing platform, the electromagnetic array module is electrified; when the unmanned aerial vehicle takes off from the take-off and landing platform, the electromagnetic array module is powered off.

In order to prevent the reverse connection of the positive electrode and the negative electrode, a diode is connected to a positive charging branch of the lithium battery. When the lithium battery is correctly connected with the charging device, the diode is forward biased, and the lithium battery is normally charged; when the lithium battery is reversely connected with the charging device, the diode is reversely biased at the moment, the charging circuit is disconnected, and the reverse connection of the positive electrode and the negative electrode is avoided.

As shown in fig. 6, the control module uses Arduino UNO as a main control board, a pin GND of the UNO is connected with a negative electrode of 5v direct-current voltage of the power module, and a pin Vin is connected with a positive electrode of 5v direct-current voltage; the analog pins A0 and A1 are respectively connected with two ends of a small resistor R1 (with the resistance value of 0.1 omega); the digital pin D0 is connected to the input anode of the electromagnet array module, pin D1 is connected to the input port of the communication module, pin D2 is connected to the output port of the communication module, and the UNO is grounded to the electromagnet array module and the communication module.

The control module has a work flow as shown in fig. 7: firstly, when the quad-rotor unmanned aerial vehicle stops on a take-off and landing boss for autonomous charging, the communication module outputs a high-level signal of 'request for charging', and the high-level signal is transmitted to a main control board UNO of the control module through a digital pin D2;

then, the main control board UNO calculates the voltage difference value between two ends of a small resistor R1 read in from the pins A0 and A1, judges whether the voltage difference value is smaller than 10mv, and if the voltage difference value is smaller than 10mv, the pin D1 sends a non-contact low-level signal to the communication module to indicate the unmanned aerial vehicle to readjust the pose; otherwise, the female head and the male head are well contacted and are not reversely connected, namely, the lithium battery of the unmanned aerial vehicle is connected into the charging circuit, and then charging is started; meanwhile, the UNO sends an electrifying signal to the electromagnet array module through the pin D0, and the electromagnet array starts to work to firmly adsorb the unmanned aerial vehicle.

When the unmanned aerial vehicle finishes charging or artificially interrupts charging, the communication module sends a low level signal of 'stopping charging', and the low level signal is transmitted to the main control panel UNO through a digital pin D2; the UNO sends a "power off" signal to the electromagnet array module via pin D0 and the electromagnet array stops operating. And 5s of time delay, after the electromagnet array module is demagnetized, the main control board UNO sends a 'takeoff enabling' signal to the communication module through the pin D1, and the unmanned aerial vehicle freely takes off and lands.

The circuit can realize the real-time monitoring of the charging state: when four rotor unmanned aerial vehicle charge, the controller measures the voltage at small resistance both ends every 0.1s, indirectly obtains charging circuit's break-make information, if charging circuit disconnection (for example charging device contact failure, reversal), controller control communication module instructs unmanned aerial vehicle readjustment position appearance, and is closed again until the charging line, unmanned aerial vehicle continues to charge.

For a quad-rotor unmanned aerial vehicle, the controller design of the quad-rotor unmanned aerial vehicle is based on local linear approximation of a dynamic model. And when four rotor unmanned aerial vehicle tracked moving platform, its gesture change is great, no longer satisfies the condition of linearization, and traditional controller design can bring very big error. In addition, the unmanned aerial vehicle can be interfered by an irregular wind field when flying outdoors, and can collide with a charging device in the landing and charging processes, so that higher requirements on the robustness and the anti-interference capability of the controller are provided. Aiming at the problems, the invention designs a corresponding control algorithm.

(1) Dynamic modeling of four rotors:

as shown in FIG. 8, the inertia system fixed on the ground is setConstruction machine system with four rotor centroids as coordinate originsFirst and second body axesIn the plane formed by the four rotors, and a third body axisPerpendicular to this plane and pointing downwards.

And defining an unit orthogonal matrix R of the four rotors to realize the transformation of vector coordinates from a machine system to an inertia system. The mass and moment of inertia matrix of the four rotors are recorded as m and J respectively, the position and the speed of the four rotors in an inertia system are x and v respectively, the angular speed in the machine system is omega, and the distance from the center of mass of the four rotors to a motor is d. The lift force generated by the ith motor is f_iGenerating a reaction torque of tau_iAnd τ_iAlong the edgeDirection of motor speed is omega_i. The magnitude of resultant external force generated by the four rotors is f, and the resultant external moment is M, wherein M is [ tau ]_x τ_y τ_z]^T. The four-rotor layout is in an X shape, and the following relation can be obtained according to the control distribution matrix of the four rotors:

wherein c is_TAnd c_MThe lift coefficient and the torsion coefficient of the four rotors are respectively.

For the sake of controller convenience in the following, a cross-product matrix symbol is defined, which satisfies for two vectors x, y:

wherein if x ═ x₁ x₂ x₃]^TThen, then

The following gives a dynamic model of the quadrotors and introduces an external disturbance force Δ to ensure the disturbance resistance of the control law_xAnd disturbance moment delta_R。

(2) Controller design

And designing a controller according to a four-rotor dynamic model, wherein the controlled quantity is the magnitude f of the combined external force and the combined external moment M. To avoid errors due to near linearization at the equilibrium point, the controller directly processes the non-linear model containing the interference signal. Meanwhile, the design of the whole controller is finished in an inertial system without involving the expression of an Euler angle, so that the singularity problem caused by the Euler angle under the condition of large mobility can be avoided; the controller is a nonlinear geometry controller.

The controller can be divided into two parts, firstly, the external moment M is combined in the design to achieve posture stabilization, and secondly, the external force magnitude f is combined in the design to achieve position stabilization. The method comprises the following specific steps:

design of position controller

Let the given smoothed ideal position signal be x_d(t), defining position and velocity tracking errors as:

e_x＝x-x_d，

integral term for simultaneous definition of tracking error

Wherein, c₁Is a selected normal number.

Defining a saturation function sat_σ

Defining a desired poseAnd desired angular velocity:

wherein the content of the first and second substances,each feedback coefficient is a positive number; k is a radical of_xA feedback coefficient that is a position tracking error; e.g. of the type_xIs the position tracking error; k is a radical of_vA feedback coefficient that is a velocity tracking error; e.g. of the type_vIs the velocity tracking error; k is a radical of_iA feedback coefficient that is a tracking error; e.g. of the type_iAn integral term for the tracking error;second derivative of the ideal position signal;

for b_1cIn order to ensure that the orientation of the expected gesture is the same as the direction of the expected motion trail, the gesture is taken

Design position controller

The following are parameter selection parts:

let Ψ (R (0), R_c(0))＜ψ₁＜1,||e_x(0)||＜e_max，||Δ_x||≤δ_x。

The parameters are selected to meet the following conditions:

(1)k_iσ＞δ_x

note the book

The parameters need to be satisfiedWherein λ_mRepresenting the minimum of the matrix eigenvalues.

Second attitude controller

The attitude tracking error is first defined as follows:

wherein V is the inverse transformation of the fork-by-matrix symbol ^:

e_Ω＝Ω-R^TR_dΩ_d

defining the integral term of the attitude tracking error:

designing an attitude controller:

wherein each control parameter is a positive number and satisfies the following condition:

remember | | (2J-tr [ J ]]I)||||Ω_d||＜B₂

The parameters satisfy:

wherein λ_mRepresenting the minimum value of the eigenvalues of the matrix, λ_MRepresents the maximum value of the matrix eigenvalues.

The specific work flow of the vehicle-mounted unmanned aerial vehicle autonomous charging platform is as follows:

(1) tracking phase

In the tracking stage, the unmanned aerial vehicle is far away from the take-off and landing boss, and GPS navigation is adopted. The unmanned aerial vehicle establishes communication with a vehicle where the charging platform is located, informs a driver of properly reducing the vehicle speed and keeping constant-speed straight running; and simultaneously acquiring GPS information of the vehicle, calculating relative speed and direction by combining the GPS information of the vehicle, and controlling speed difference to approach the charging platform.

(2) Visual search phase

When the unmanned aerial vehicle arrives near the charging platform, the car roof hangar is opened, the airborne camera enters a visual search state, and characteristic patterns on the lifting boss are searched. After the unmanned aerial vehicle recognizes the characteristic pattern, the relative position and posture of the unmanned aerial vehicle and the lifting boss are adjusted through a machine vision algorithm, and the center of the unmanned aerial vehicle is aligned.

(3) Landing stage

And finally, slowly descending the unmanned aerial vehicle, and continuously adjusting the posture according to a machine vision algorithm so that the positive and negative electrodes of the charging interface male and female connectors are aligned. Simultaneously, the electro-magnet in the annular groove also further drags guide unmanned aerial vehicle landing leg to the correct position. After the landing is successful, the unmanned aerial vehicle starts to charge, and the roof of the car roof garage is closed.