Lightweight operation method for agricultural phenotype acquisition holder system

Abstract

The invention belongs to the technical field of intelligent agriculture, and particularly relates to a lightweight operation method for an agricultural phenotype acquisition holder system. Comprising the following steps: S1, carrying out mass and position calibration on various sensors, connecting pieces and accessories mounted on a holder, and establishing a multi-source load mass distribution model; s3, modeling gravitational torque caused by the eccentric load; s4, introducing a disturbance perception and feed-forward compensation mechanism; s5, constructing a control parameter adaptive adjustment mechanism considering the stability precision and the energy consumption level; and S6, establishing a determination and closed-loop maintenance mechanism of a lightweight operation state. The equivalent rotational inertia and the driving burden are remarkably reduced, the attitude adjustment energy consumption is effectively reduced, the energy utilization efficiency is improved, the dynamic response performance and the attitude stability quality of the system are improved, and the adaptive capacity and the operation reliability under the multi-sensor cooperative working condition are enhanced; and the comprehensive performance of the system is improved on the premise that the structural strength is not obviously reduced.

Description

Technical Field

[0001] This invention relates to the field of smart agriculture technology, specifically to a lightweight operation method for an agricultural phenotyping gimbal system. Background Technology

[0002] As agricultural robot technology develops towards high-throughput phenotypic data acquisition, mobile data acquisition platforms are gradually shifting from single-sensor systems to multi-source sensor collaborative operation modes. To acquire multidimensional growth information of crops, the platform needs to simultaneously carry visible light imaging equipment, multispectral imaging equipment, laser ranging equipment, and thermal imaging equipment, and the spatial arrangement of these devices has considerable uncertainty.

[0003] Existing agricultural phenotyping gimbal systems are typically designed with structural strength and drive capability configured based on a fixed load assumption. However, during actual operation, due to sensor replacements, adjustments to installation locations, and environmental disturbances, the system load distribution exhibits significant time-varying characteristics. This load variation alters the dynamic parameters of the gimbal system, causing a discrepancy between the model established during parameter tuning and the actual operating state, thereby reducing the effectiveness of attitude stabilization control.

[0004] Furthermore, traditional lightweight designs often focus on structural weight reduction, such as using high-strength lightweight materials or optimizing structural topology. However, in the complex environment of agriculture, simply relying on structural weight reduction may lead to a decrease in system stiffness or insufficient impact resistance, making it difficult to meet the requirements for long-term stable operation. Therefore, from the perspective of synergistic optimization of system dynamics and control strategies, achieving lightweight operation by adjusting mass distribution and controlling energy output has become an important technical approach to improve the performance of agricultural phenotyping equipment. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0007] A lightweight operation method for an agricultural phenotyping gimbal system includes the following steps:

[0008] S1: Perform mass and position calibration on various sensors, connectors, and accessories mounted on the pan-tilt unit, and establish a multi-source load mass distribution model. Assume the system includes... The load unit, the first The mass of each unit is The position vector in the gimbal coordinate system is The total mass of the combined system is:

[0009]

[0010] The overall center of gravity coordinates of the system are:

[0011] ;

[0012] S2: Calculate the equivalent rotational inertia for the roll axis, pitch axis and yaw axis respectively;

[0013] S3: Modeling the gravitational torque caused by eccentric load: When the distance from the equivalent center of gravity of a certain load combination to the axis of rotation is d, and the attitude angle is θ, the gravitational disturbance torque is expressed as:

[0014]

[0015] g is the acceleration due to gravity;

[0016] S4: Introducing disturbance sensing and feedforward compensation mechanism: Let the linear acceleration vector measured by the chassis IMU be a. b The coordinate transformation matrix corresponding to the current attitude of the gimbal is R. bg Then, the equivalent disturbance acceleration in the gimbal coordinate system is expressed as:

[0017]

[0018] If the radius vector of an equivalent load relative to the rotating axis is r, then the inertial torque caused by the disturbance can be approximately expressed as:

[0019]

[0020] In the control implementation, this disturbance torque is added as a feedforward term to the control input, resulting in:

[0021]

[0022] Among them, u fb For the feedback controller output, K g To compensate for the feedforward gain due to gravity, K d For perturbation feedforward gain;

[0023] S5: Construct an adaptive adjustment mechanism for control parameters that balances stability, accuracy, and energy consumption.

[0024] S6: Establish a mechanism for determining and maintaining lightweight operating conditions in a closed-loop manner.

[0025] As a preferred embodiment of the lightweight operation method of the agricultural phenotyping gimbal system described in this invention, the specific method of S2 is as follows: taking a certain rotating axis k as an example, if the shortest distance from the i-th load unit to the axis is r... ik Then the equivalent moment of inertia of the shaft is:

[0026]

[0027] Among them, J k0 This represents the moment of inertia of the gimbal body corresponding to this axis.

[0028] As a preferred embodiment of the lightweight operation method of the agricultural phenotyping gimbal system described in this invention, the specific method of S5 is as follows: taking the improved cascaded PID as an example, the outer loop position controller determines the position based on the angle error e. θ Generate target angular velocity ω r The inner loop speed controller is based on the speed error e ω The discrete form of the generated actuator control quantity is written as:

[0029]

[0030]

[0031] To avoid excessive accumulation of integrals during small-angle adjustments, and to further introduce an energy consumption constraint term, the motor output power per unit time is approximated as:

[0032]

[0033] The control energy consumption within one work cycle is:

[0034]

[0035] The optimization objective for the control parameters is expressed as:

[0036] .

[0037] As a preferred embodiment of the lightweight operation method of the agricultural phenotyping gimbal system described in this invention, the specific method of step S6 is as follows: the system uses an equivalent inertia J k eccentricity d, peak driving torque τ max Energy consumption per unit cycle E c and attitude steady-state error |e θ | As a comprehensive evaluation indicator, the system is considered to be in a lightweight operation state when the following conditions are met:

[0038]

[0039] in, These are preset thresholds.

[0040] Compared with the prior art, the beneficial effects of the present invention are: (1) Significantly reducing the equivalent moment of inertia and driving load: By optimizing and controlling the spatial installation position of the multi-source sensors, the mass distribution radius in each rotation axis direction is reduced, thereby effectively reducing the equivalent moment of inertia of the system. The output torque required by the drive actuator to achieve the same attitude control accuracy is significantly reduced, the peak load and continuous operating current of the motor are reduced, the thermal load level of the drive system is reduced synchronously, and the overall operation is more stable and reliable.

[0041] (2) Effectively reduce attitude adjustment energy consumption and improve energy utilization efficiency: This invention combines disturbance feedforward compensation with control parameter energy consumption constraints, which significantly reduces the ineffective adjustment amount output by the feedback controller, thereby reducing control energy consumption per unit operation cycle while ensuring attitude stability accuracy. Compared with traditional control strategies that only aim to minimize error, this invention can achieve "low-energy stable control", demonstrating a lightweight effect from the system operation level.

[0042] (3) Improve the dynamic response performance and attitude stability of the system: Due to the reduction of equivalent inertia and the early compensation of disturbance torque, the dynamic lag phenomenon of the gimbal system when subjected to vehicle vibration or ground disturbance is significantly reduced, the attitude adjustment overshoot and adjustment time are reduced, and the closed-loop response of the control system is faster and more stable, thereby improving the image acquisition clarity and data validity.

[0043] (4) Enhance the adaptability and operational reliability under multi-sensor collaborative working conditions: By establishing a lightweight operating state determination and closed-loop maintenance mechanism, the present invention enables the system to automatically maintain a better dynamic state when the sensor is replaced, the installation position is adjusted, or the working environment changes, thereby avoiding the decline in control performance or drive overload caused by changes in load parameters, thus improving the long-term stable operation capability of agricultural phenotyping equipment.

[0044] (5) Achieving comprehensive system performance improvement without significantly reducing structural strength: This invention does not rely solely on structural weight reduction, but achieves unified driving and control of lightweighting through mass distribution regulation and control strategy optimization. This enables the system to achieve lower energy consumption, higher stability and longer service life while maintaining necessary stiffness and impact resistance, and has good engineering promotion value and industrial application prospects. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0046] Figure 1 This invention provides a lightweight operation method for an agricultural phenotyping gimbal system, which uses a multi-source load mass and spatial installation location calibration diagram.

[0047] Figure 2 The diagram shows the equivalent rotational inertia calculation of each rotating axis in a lightweight operation method for an agricultural phenotyping gimbal system according to the present invention.

[0048] Figure 3 This is a force analysis diagram of the rotating shaft of a lightweight operation method for an agricultural phenotyping gimbal system according to the present invention.

[0049] Figure 4 This is a schematic diagram of the disturbance sensing and feedforward compensation mechanism of a lightweight operation method for an agricultural phenotyping gimbal system according to the present invention. Detailed Implementation

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0051] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0052] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0053] The purpose of this invention is to provide a lightweight operation method for an agricultural phenotyping gimbal system. This method elevates "lightweighting" from a geometric and material-level concept to a comprehensive optimization goal encompassing dynamics and control. By establishing a load mass distribution model, an equivalent moment of inertia model, an eccentric gravitational moment model, and a control energy consumption evaluation model, the method achieves adaptive lightweight operation of the gimbal system under different sensor combinations, operating postures, and external disturbances. This invention aims to protect not only the adjustment scheme for a specific structural position, but also the methodological approach of "reducing drive load and control energy consumption through dynamic adjustment of mass distribution and linkage control strategies." This technical approach differs fundamentally from existing solutions that simply reduce weight, isolate vibration, or rely on feedback control, possessing a stronger creative foundation and higher engineering applicability.

[0054] To highlight the theoretical basis of this invention, the lightweight objective can be formally represented as a multi-constraint optimization problem. Let the total mass of the system be... The mass of the i-th load unit is Its perpendicular distance relative to a certain axis of rotation is Then the equivalent moment of inertia in the direction of that axis can be expressed as:

[0055] (1)

[0056] in, Let be the inherent moment of inertia of the gimbal body relative to this axis. As can be seen from this equation, even with the total mass... The size remains the same; the size can be reduced simply by adjusting the installation position. It can still significantly reduce Therefore, this invention defines the lightweight objective as minimizing the overall cost function under constraints:

[0057] (2)

[0058] in, For equivalent rotational inertia, For the peak drive torque of the actuator, Energy consumption is controlled within a unit operating cycle, and the weighting factor is used. The objective function embodies the core of the invention's creativity, which distinguishes it from existing solutions. Instead of focusing solely on minimizing structural mass, it aims to minimize the three elements of inertia, peak torque, and energy consumption in a coordinated manner.

[0059] The steps of this invention include not only sensor quality modeling, center of gravity position adjustment and attitude control, but also the establishment of a unified mathematical description framework around equivalent inertia, gravitational torque, disturbance compensation and control energy consumption, so as to ensure that the method has a clear technical implementation path and verifiable engineering effects.

[0060] Specifically, a lightweight operation method for an agricultural phenotyping gimbal system includes the following steps:

[0061] S1, please refer to Figure 1 The mass and position of various sensors, connectors, and accessories mounted on the pan-tilt unit are calibrated to establish a multi-source load mass distribution model. The system includes... The load unit, the first The mass of each unit is The position vector in the gimbal coordinate system is The total mass of the combined system is:

[0062] (3)

[0063] The overall center of gravity coordinates of the system are:

[0064] (4)

[0065] This model allows for real-time assessment of the spatial bias of load combinations, serving as the basis for subsequent inertia calculations and center of gravity adjustment. The key to this step lies not in simple weight measurement, but in constructing a parameterized mass distribution expression oriented towards the dynamics of the rotating axis, providing a quantitative basis for lightweight operation.

[0066] S2, please refer to Figure 2 The equivalent moments of inertia are calculated separately for the roll, pitch, and yaw axes. Taking a certain rotating axis k as an example, if the shortest distance from the i-th load unit to this axis is r... ik Then the equivalent moment of inertia of the shaft is:

[0067] (5)

[0068] Among them, J k0 This represents the rotational inertia of the gimbal body corresponding to this axis. It can be seen that when the arrangement radius of the sensor relative to the rotation axis decreases, the equivalent inertia faced by the drive system decreases synchronously. This is precisely the theoretical starting point for the "dynamic mass distribution control" of this invention to achieve lightweight operation.

[0069] S3, please refer to Figure 3 The gravitational torque caused by eccentric load is modeled. When the distance from the equivalent center of gravity of a certain load combination to the axis of rotation is d, and the attitude angle is θ, the gravitational disturbance torque can be expressed as:

[0070] (6)

[0071] Where g is the acceleration due to gravity. If d approaches zero, the gravitational torque disturbance decreases synchronously, and the output of the actuator used to counteract the static off-center load decreases accordingly. Therefore, this invention, by setting an adjustable mounting structure in the X, Y, and Z directions, controls p c Spatial control is employed to minimize d, thereby reducing gravitational torque, continuous drive current, and motor heat generation. This approach differs from directly increasing motor margin or improving control gain; instead, it achieves drive weight reduction by minimizing the source of disturbance torque itself.

[0072] S4, please refer to Figure 4 To reduce control energy consumption under dynamic operating conditions, a disturbance sensing and feedforward compensation mechanism is introduced. Let the linear acceleration vector measured by the chassis IMU be a. b The coordinate transformation matrix corresponding to the current attitude of the gimbal is R. bg Then, the equivalent disturbance acceleration in the gimbal coordinate system can be expressed as:

[0073] (7)

[0074] If the radius vector of an equivalent load relative to the axis of rotation is r, then the inertial torque caused by the disturbance can be approximately expressed as:

[0075] (8)

[0076] In the control implementation, this disturbance torque can be added to the control input as a feedforward term, resulting in:

[0077] (9)

[0078] Among them, u fb For the feedback controller output, K g To compensate for the feedforward gain due to gravity, K d The disturbance feedforward gain is used. In this way, the feedback controller no longer bears the entire disturbance suppression task alone; instead, the feedforward channel preemptively cancels measurable and estimable disturbances, thereby reducing the output peak and ineffective regulation of the feedback loop, achieving the effect of "lightweight control." The paper has verified that the combination of dual feedforward and improved cascaded PID can improve dynamic response and reduce overshoot, providing engineering feasibility support for the method steps of this invention.

[0079] S5 constructs an adaptive adjustment mechanism for control parameters that balances stability, accuracy, and energy consumption. Taking the improved cascade PID as an example, the outer loop position controller adjusts the parameters according to the angle error e. θ Generate target angular velocity ω r The inner loop speed controller is based on the speed error e ω Generate actuator control input. Its discrete form can be written as:

[0080] (10)

[0081] (11)

[0082] To avoid excessive integral accumulation during small-angle adjustments, this invention adopts the "integral separation + integral limiting + error zero-crossing reset" concept from the improved cascade PID controller, and further introduces an energy consumption constraint term. Let the motor output power per unit time be approximately:

[0083] (12)

[0084] The control energy consumption within one work cycle is:

[0085] (13)

[0086] The optimization objective for control parameters can be expressed as:

[0087] (14)

[0088] The objective function is designed to constrain attitude error (first term), control energy (second term), and control output rate of change (third term) to avoid large excitations and frequent adjustments. This objective function demonstrates the invention's further innovation compared to existing control schemes: it does not simply aim to minimize tracking error, but incorporates "low-energy stable control" as part of the control law design.

[0089] S6 establishes a mechanism for determining and maintaining a lightweight operating state. The system uses an equivalent inertia J. k eccentricity d, peak driving torque τ max Energy consumption per unit cycle E c and attitude steady-state error |e θ | As a comprehensive evaluation indicator, the system can be determined to be in a lightweight operation state when the following conditions are met:

[0090] (15)

[0091] in, These are preset thresholds. If any indicator exceeds the limit, the system re-executes the quality distribution adjustment or control parameter optimization steps. This forms a complete closed-loop method flow, enabling the invention to move beyond static design and become a sustainable, adaptive, and lightweight operation method oriented towards the entire operation process.

[0092] Example

[0093] In a mobile phenotyping platform for facility agriculture, the pan-tilt system is equipped with an imaging unit integrating a multispectral camera, a thermal imager, and a data storage module. The imaging unit is mounted on the pan-tilt axis support via an adjustable slide rail, and its initial combined load has a total mass of approximately 4.8 kg. Before system operation, the mass and spatial position of each load unit are calibrated, and a mass distribution model is established. Calculation results show that, in the initial installation state, the equivalent moment of inertia along the pan-tilt axis is approximately 0.42 kg·m².

[0094] During the lightweight operation and control process, the system first moves the imaging unit about 60mm in the direction of rotation axis by adjusting the slide rail, thereby reducing its effective radius. At the same time, the installation structure is locally optimized. After the structural weight reduction and mass distribution optimization are combined, the total mass of the gimbal assembly load is reduced to about 4.3kg, and the equivalent rotational inertia in the pitch axis direction is reduced to about 0.31kg·m², with an inertia reduction of about 26%.

[0095] During actual operation, the chassis inertial measurement unit acquires vehicle vibration acceleration information in real time, and the disturbance feedforward compensation is generated by attitude transformation and superimposed on the output of the improved cascade PID controller, so that the actuator only needs to output a small adjustment torque to maintain attitude stability.

[0096] The results of the greenhouse mobile operation test show that after adopting the lightweight operation method of the present invention, the peak current of the gimbal drive motor is reduced from about 3.6A to 2.8A, the average energy consumption per unit operation cycle is reduced by about 18%, the attitude adjustment overshoot is reduced by about 30%, and the image acquisition stability is significantly improved, which verifies the lightweight operation effect of the method of the present invention under multi-sensor collaborative working conditions.

[0097] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A lightweight operation method for an agricultural phenotyping gimbal system, characterized in that, Includes the following steps: S1: Perform mass and position calibration on various sensors, connectors, and accessories mounted on the pan-tilt unit, and establish a multi-source load mass distribution model. Assume the system includes... The load unit, the first The mass of each unit is The position vector in the gimbal coordinate system is The total mass of the combined system is: ； The overall center of gravity coordinates of the system are: ； S2: Calculate the equivalent rotational inertia for the roll axis, pitch axis and yaw axis respectively; S3: Modeling the gravitational torque caused by eccentric load: When the distance from the equivalent center of gravity of a certain load combination to the axis of rotation is d, and the attitude angle is θ, the gravitational disturbance torque is expressed as: ； g is the acceleration due to gravity; S4: Introducing disturbance sensing and feedforward compensation mechanism: Let the linear acceleration vector measured by the chassis IMU be a. b The coordinate transformation matrix corresponding to the current attitude of the gimbal is R. bg Then, the equivalent disturbance acceleration in the gimbal coordinate system is expressed as: ； If the radius vector of an equivalent load relative to the rotating axis is r, then the inertial torque caused by the disturbance can be approximately expressed as: In the control implementation, this disturbance torque is added as a feedforward term to the control input, resulting in: Among them, u fb For the feedback controller output, K g To compensate for the feedforward gain due to gravity, K d For perturbation feedforward gain; S5: Construct an adaptive adjustment mechanism for control parameters that balances stability, accuracy, and energy consumption. S6: Establish a mechanism for determining and maintaining lightweight operating status.

2. The lightweight operation method of an agricultural phenotyping gimbal system according to claim 1, characterized in that, The specific method of S2 is as follows: Taking a certain rotating axis k as an example, if the shortest distance from the i-th load unit to the axis is r ik Then the equivalent moment of inertia of the shaft is: Among them, J k0 This represents the moment of inertia of the gimbal body corresponding to this axis.

3. A lightweight operation method for an agricultural phenotyping gimbal system according to claim 1, characterized in that, The specific method of S5 is as follows: Taking the improved cascaded PID as an example, the outer loop position controller determines the angle error e based on the angle error e. θ Generate target angular velocity ω r The inner loop speed controller is based on the speed error e ω The discrete form of the generated actuator control quantity is written as: To avoid excessive accumulation of integrals during small-angle adjustments, and to further introduce an energy consumption constraint term, the motor output power per unit time is approximated as: The control energy consumption within one work cycle is: The optimization objective for the control parameters is expressed as: 。 4. A lightweight operation method for an agricultural phenotyping gimbal system according to claim 1, characterized in that, The specific method of S6 is as follows: the system uses an equivalent inertia J k eccentricity d, peak driving torque τ max Energy consumption per unit cycle E c and attitude steady-state error |e θ | As a comprehensive evaluation indicator, the system is considered to be in a lightweight operation state when the following conditions are met: in, These are preset thresholds.

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